MPCA Report

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Package 1

U.S. TACONITE IRON ORE INDUSTRY

Part 1. Introduction

Iron ore is mined and processed in the U.S. mainly on the Mesabi Range of northern Minnesota 

and the Marquette Range of the Upper Peninsula of Michigan.

Mesabi Range

The Mesabi Range, shown in Figure 1 and located approximately 65 miles north of Duluth, MN, 

consists of a belt of (the Animikie Biwabik) iron formation of approximately 120 miles long 

from Grand Rapids to Babbitt with a thickness of 400 to 750 feet. The iron-ore material that is 

mined, concentrated, and pelletized is magnetite (Fe3O4), or magnetic taconite.

There are two types of magnetic taconite: 1) magnetite associated with minnesotaite, 

stilpnomelane, and cherty quartz with minor greenalite and carbonates, and 2) magnetite

associated with iron amphiboles (grunerite, cummingtonite, actinolite), pyroxenes, garnet, 

fayalite, and finely granular quartz. The first type occurs westward from near Aurora, where five 

taconite mining and processing companies (Ispat-Inland Steel Mining Company, EVTAC 

Mining, U.S. Steel Minnesota Ore Operations, Hibbing Taconite Company, and National Steel 

Pellet Company) are located. The second type is found from Aurora eastward, in an area where 

the iron formation has been metamorphosed by the intrusion, on the south, of the Duluth Gabbro. 

Northshore Mining Company and LTV Steel Mining Company are located in this area. See 

Table 1 for facility locations.

The difference in ore type affects grinding circuit design. According to one facility, a typical east 

Mesabi magnetic taconite concentrate ground to 90% finer than 325 mesh (43 m) contains 

about 8% slica. Half of the total silica is in the 10% by weight +325 mesh portion. Currently, a 

flotation step is added to further remove silica to make a marketable taconite concentrate for 

standard or fluxed pellet production. At a west Mesabi facility, ore ground to 75% finer than 325 

mesh is all that is required. No flotation step is needed for further silica removal, in order to 

make a marketable taconite concentrate for standard pellet production.

The difference in ore type also affects crushing circuit design. At the west Mesabi facility

mentioned above, single stage crushing (gyratory crushers) is used ahead of single stage 

autogenous (using large pieces of the ore to grind/mill the smaller pieces) grinding, although 

grinding is now enhanced with pebble crushers. Most facilities, especially those at the eastern 

end of the Mesabi Range, use three or four stages of crushing, followed by rod and ball grinding 

mills.

The difference in ore type is also apparently relevant to the content of mercury and fine mineral 

fibers in the taconite ore processed on the Mesabi Range, and hence also the emission rates of 

these constituents.
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Marquette Range

The Marquette Range is located in the northern part of the Upper Peninsula of Michigan with its 

eastern end 10 miles west of the Lake Superior port of Marquette. The range is approximately 30 

miles long and 6 miles wide, including from east to west the towns of Palmer, Negaunee, 

Ishpeming, Humboldt, Republic, and Michigamme. Figure 2 shows the location of the 

Marquette Range in relation to the Mesabi Range as well as other iron ore deposits currently not 

being mined.

Empire Iron Mining Partnership at Palmer and Tilden Mining Company at Ishpeming are the two 

facilities currently operated on the Marquette Range. The Empire plant uses magnetite to make 

pellets, and the Tilden plant uses both hematite (Fe2O3) and magnetite. In the finished (fired) 

pellets, magnetite is converted to hematite.

Taconite Pellets - Basics

Taconite concentrate pellets, or taconite pellets for short, are of 3/8 to 1/2 inches in diameter, 

made of taconite concentrate with a binding agent (e.g., 10 to 20 lb of powdered bentonite per 

ton of concentrate) and other additives and heat hardened at about 2400 °F. Taconite pellets have

an iron content of about 65% by weight.

Iron making blast furnaces have used taconite pellets for decades, because of their requisite 

strength, consistency in size and chemical composition, and optimum metallurgical properties. If 

taconite concentrates, which are very fine particles, were used instead to build the burden of a 

blast furnace, they would be blown out of the furnace before the metallurgical process starts. The 

physical strength of taconite pellets also facilitates transportation and handling.

Pellet Types

There are basically two types of pellet products -- standard pellets (SP), often called “acid” 

pellets in the past, and fluxed pellets. Fluxed pellets contain a certain amount of fluxstone 

(limestone and/or dolomite) in addition to all the constituents of standard pellets.

Fluxed pellets of equal to or greater than 1.0 basicity ratio can be called fully fluxed pellets 

(FFP). As an industry convention, the basicity ratio is a mass ratio of several of the pellet 

constituents defined as (CaO + MgO)/(SiO2 + Al2O3). Energy demand in the pelletizing process 

for fully fluxed pellets is increased due to the added calcination requirement for the fluxstone. 

Auxiliary burners are usually added to the pelletizer (agglomerator or indurating furnace) in order 

to make fully fluxed pellets. As a result, FFP production leads to higher emissions of air 

pollutants than SP production.

Fluxed pellets of less than 1.0 basicity ratio, or partially fluxed pellets (PFP), do not require 

auxiliary burners. The difference in emissions between PFP and SP production is often not 

apparent.

The various pellet products are made to meet the blast furnace operator’s requirements. Blast 

furnace operators can build their burden with FFP without adding any more fluxing agent. 
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Alternatively, they can build their burden with PFP or SP while also adding some additional 

fluxing agents.

Pellet chips (PC) are broken pieces of fired pellets. They can be sent back to the balling process, 

after regrinding, and remade into furnace feed (unfired pellets or “green” balls). Pellet chips can 

be sold as feed to sinter plants.

Types of Pelletizers

The U.S. taconite iron ore industry uses three types of pelletizing machines or processes: straight 

grate (Figure 3), vertical shaft (Figure 4), and grate-kiln (Figures 5A and 5B), with their 

respective first units installed in 1954, 1957, and 1963. Based on published production data for 

1995 through 1997, 63.0% of the total U.S. pellet production is made with the grate-kiln 

pelletizers, 24.5% with the straight grate pelletizers, and 12.5% with the vertical shaft pelletizers. 

An industry profile is provided in Table 2.

In the vertical shaft furnace (Figure 4), the feed (wet green balls) are distributed evenly over the 

top of the slowly descending bed of pellets (1 to 11⁄2 inches per minute, or about 4 hours of 

residence time in the furnace). Gravitational force and actions of the chunkbreaker create the 

downward displacement movement of pellets. A rising stream of hot gas of controlled 

temperature flows counter to the descending bed of pellets. Fuel combustion chambers supply

hot gas midway between the top and bottom of the furnace. The oxidation of ferrous iron (Fe+2) 

in the pellets, which is an exothermic or heat releasing reaction, also contribute to heating the 

pellets above the oxidation zone. (According to one facility, a rule of thumb is that, for each 

percent increase in ferrous iron, approximately 25,000 BTU less fuel is need to process each 

long ton of pellets at its straight grate pelletizer, which is discussed in the next paragraph.) The 

oxidation of ferrous iron occurs for pelletizing magnetite, but not hematitic or limonitic ores. 

The vertical shaft furnace did not pass feasibility testing for making fluxed pellets, which have 

higher energy demand than standard pellets. The furnace was considered more energy efficient, 

however, than the straight grate pelletizer of the 1950s, before the improvements and retrofits for 

heat recuperation were made to the straight grate pelletizer and also before a new type of 

pelletizer, the grate-kiln system, entered the taconite ore processing industry. During a recent 

stack test, a typical vertical shaft furnace made fired pellets at a rate of 54 ton/hour with heat 

input of 25 million Btu/hr and a waste gas flow rate of 43,200 ft3/min (at dry, standard 

conditions).

In the straight grate machine (Figure 3), a continuous bed of agglomerated green pellets is carried 

through different temperature zones with upward draft or downward draft blown through the 

pellets on the metal grate. Pellet residence time inside the machine is about 40 minutes. Fuel 

combustion chambers supply hot flue gas to a zone in the middle portion of the machine 

(combustion zone). (In order to make fully fluxed pellets, auxiliary burners need to be added to 

the preheating zone.) Fired pellets are cooled on the remaining portion of the machine. To 

protect the metal grate and other parts of the machine, about 20 percent of the cooled, fired 

pellets are used to make a hearth layer at the bottom and two sides of the pellet bed. In a recent 

stack test of a four-stack (see more description in the next paragraph) straight grate machine, the 
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machine made fully fluxed pellets at a rate of 377 ton/hour with heat input of 183 million Btu/hr 

and an exhaust gas flow rate of 148,000 ft3/min per stack (at dry, standard conditions).

For the straight grate machine, used process gas consists of exhaust gas from the updraft drying 

zone and exhaust gas closer to the firing zone. The former can be called “hood exhaust” and the 

latter “windbox exhaust.” For many straight grate machines, both hood exhaust and windbox 

exhaust are directed to one common header. The common exhaust header has one “hot side” 

inlet to receive windbox exhaust and one “cold side” inlet to receive hood exhaust. From the 

common exhaust header, the exhaust gas is vented through four parallel stacks, which are 

outfitted with air pollution control equipment. For some older machines, two separate common 

headers are used to vent hood exhaust and windbox exhaust. The hood exhaust header vents 

through three stacks, and the wind exhaust (often referred to as “waste gas”) header vents 

through two stacks.

The grate-kiln system actually consists of a traveling grate, a rotary kiln, and an annular cooler 

(Figures 5A and 5B). Pellet residence time inside the system is about 55 minutes (less than 10 

minutes in the grate, about 20 minutes in the kiln, and about 30 minutes in the cooler). The 

grate-kiln system does not need a hearth layer for the grate, which handles only drying and 

preheating. The rotary kiln does not need a hearth layer, either, because it is lined with refractory

material. One waste gas stack, or two side-by-side waste gas stacks, are used for the grate-kiln 

system. In a recent stack test, a grate-kiln system made fully fluxed pellets at a rate of 459 

ton/hour with heat input of 221 million Btu/hr and a waste gas flow rate of 340,000 ft3/min 

through the waste gas stack (at dry, standard conditions). In another recent stack test, a different 

grate-kiln system, installed with two waste gas stacks, made partially fluxed pellets (no auxiliary

burner at the preheating zone in the grate) at a rate of 697 ton/hr with heat input rate of 233 

million Btu/hr and a waste gas flow rate of 232,000 ft3/min per stack (at dry, standard 

conditions).

The annular cooler for the grate-kiln system was installed originally without any gas cleaning 

equipment for the cooler vent stack. Recent stack testing has found that the operator would need 

to be very careful in process control for the cooler vent stack to be in compliance with state rules 

on particulate emissions without adding any gas cleaning equipment. One reason is that more 

additives are now used than before in making the green balls, thus demanding more energy in 

induration. An example would be the calcination required as an integral part of the production of 

fully fluxed pellets. The pellet now reaches its peak temperature in the cooler, instead of the 

kiln, as originally designed. This adds thermal buoyancy to the airborne particulates entrained 

into the gas stream through the stack. Various efforts are being made, include adding a wet 

scrubber by one facility to control some part of the dusty area near the vent stack entrance. Initial 

testing has shown that this wet scrubber addition was sufficient to bring the main cooler stack 

back into compliance with Minnesota emission limitations.

It should be noted that, since the fired pellets have traveled through the combustion zone in the 

kiln, where the flue gas flows countercurrent to the fired pellets, only small quantities of volatile 

hazardous air pollutants are expected to be emitted from the cooler vent stack. No stack test had 

been conducted to validate this expectation, as this report was being finalized. On the other 
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hand, stack testing results did show that the particulate emissions from the cooler vent stack tend 

to be coarse in size, limiting impact on ambient air quality due to rapid settling.

It is very common to use intermediate cyclones to clean the gas stream in the straight grate and 

grate-kiln pelletizers, as it is ducted to various locations in the grate. The cyclones protect the 

blades of gas movers (fans) and recover good materials (particles of high iron content). Inclined 

plates are also used along with periodic water wash to remove “solid spills” under the grate to 

recover the iron units. These measures also help reduce dust loading near the waste gas stack, 

even though they are not considered air pollution control equipment.

Pelletizing Process

Pelletizing is a high temperature process with air in excess. The process is responsible for the 

largest portion of emissions of air pollutants from any individual taconite ore mining and 

processing facility. Natural gas is commonly used as the primary fuel for pelletizing. Distillate 

fuel oil is often used as a back up fuel, especially during natural gas curtailment in winter. Other 

types of fuel, e.g., coal, petroleum coke, and sawdust, are also being used.

Many factors can significantly influence the emissions from the pelletizing process. Take the 

binding agent (binder) for example. The majority of taconite concentrate pellets are made with 

bentonite clay as a binder. Many alternatives have been tried to replace bentonite clay for cost 

control and silica reduction reasons. However, most alternative binders are still not as strong as 

bentonite clay in maintaining dry strength of the green ball (unfired pellet). During a very brief 

time span in the pelletizer, when the moisture has evaporated and the small taconite concentrate 

particles have not fused together on the green ball surface, a green ball incorporated with an 

alternative binder can be more vulnerable to disintegration. Another example of a process 

parameter that affects air emissions is the intensity of heating. If the green ball, incorporated 

with either bentonite clay or an alternative binder, is not subjected to sufficiently high heat flux 

after the moisture has evaporated, it’s vulnerability to disintegration can increase as well. 

Disintegration of green balls and/or pellets often leads to a surge in the emission of particulate 

matter (PM) from the waste gas stack.

Over the years, efforts have been made to recuperate some of heat loss associated with the 

various hot air streams associated with the pelletizers. For grate-kiln and straight grate 

pelletizers, most of the hot air in the cooling zone for fired pellets is directed to combustion zone 

and/or preheat and drying zones of the pelletizer. At the waste gas stack, the gas stream does not 

have much thermal energy to be recovered (gas temperature ranges from 100 to 150 °F for a 

stack controlled with a wet scrubber or a wet wall electrostatic precipitator, and from 200 to 300 

°F for a stack controlled with a multiclone or a simpler device). For the vertical shaft furnace, 

some heat recovery has been achieved by adding a concentrate slurry scrubbing unit (heat 

exchanger) to the existing top gas multiclone (stack gas temperature ranges from 125 to 150 °F 

with the heat exchanger, and from 230 to 300 °F without the heat exchanger).

There are many perspectives that can be used to evaluate the pelletizing operations at the 

different facilities. One simple way is to divide a facility’s annual indurating energy

consumption by its annual pellet production (million BTU/ton pellets fired), which is given in the 
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ninth column of Table 2. From 0.277 million BTU/ton pellets fired for Hibbing Taconite 

Company to 0.668 million BTU/ton pellets fired for Northshore Mining Company, one should 

begin to appreciate the significant energy usage difference among the individual facilities. Most 

of the difference is attributed to a combination of the following: process equipment age, 

equipment retrofits, pellet products made, ore characteristics, process control, and operator’s 

training and skills.

In general, a well managed pelletizing process, coupled with appropriate air pollution control 

equipment for waste gas cleaning, can attain and maintain compliance with existing emission 

limitations established in a facility’s operating permit or applicable state rules.

Taconite Mining and Processing

As stated previously, pelletizing is responsible for the largest portion of the emissions of air 

pollutants from a taconite ore mining and processing facility. However, a taconite ore mining 

and processing facility has unit processes other than just pelletizing. Some of these other 

processes such as mineral liberation and taconite concentrating are upstream of pelleting, while 

others such as pellet product storage and shipping are downstream of pelltizing. Figure 6 is a 

process diagram for a taconite ore mining and processing facility that uses the grate-kiln 

pelletizer to make fully fluxed pellets. The following describes mineral liberation, taconite 

concentrating, pellet product storage and shipping.

Liberation – The first step in processing crude taconite ore is crushing and grinding. The ore 

must be ground to a particle size sufficiently close to the grain size of the ironbearing mineral to 

allow for a high degree of mineral liberation and removal of the waste material (gangue). Most 

of the taconite used today requires very fine grinding.

The grinding is normally performed in successive stages of dry crushing, followed by wet 

grinding in rod mills and ball mills. Gyratory crushers are generally used for primary crushing, 

and cone crushers are used for secondary and tertiary fine crushing. Intermediate vibrating 

screens remove undersize material from the feed to the next crusher and allow for closed circuit 

operation of the fine crushers. The rod and ball mills are also in closed circuit with classification 

systems such as cyclones. An alternative is to feed some coarse ore directly to wet or dry

semiautogenous or autogenous (using large pieces of the ore to grind/mill the smaller pieces) 

grinding mills, then to pebble or ball mills.

Ideally, particles of iron minerals and barren gangue should be removed from the grinding 

circuits as soon as they are liberated, with larger particles returned for further grinding.

Concentrating – As the iron ore minerals are liberated by the crushing steps, the ironbearing 

particles must be concentrated. Since only about 33 percent of the crude taconite becomes a 

shippable product for iron making, a large amount of gangue is generated. Magnetic separation 

and flotation are most commonly used for concentration of taconite ore.

Magnetite is concentrated by magnetic separation since most of the recoverable iron is magnetic. 

The crude ore may contain 30 to 35 percent total iron by assay, but theoretically only about 75 
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percent of this is recoverable magnetite. The majority of the remaining iron is discarded with the 

gangue.

Nonmagnetic taconite ore (hematite and liminite) is concentrated by froth flotation or by a 

combination of selective flocculation and flotation. The method is determined by the differences 

in surface activity between the iron and gangue particles. Sharp separation is often difficult.

Various combinations of magnetic separation and flotation may be used to concentrate ore 

containing various iron minerals (magnetite and hematite) and wide ranges of mineral grain 

sizes. Flotation is also often used as a final polishing operation on magnetic concentrates.

Pellet Product Storage and Shipping – Fired pellets, just leaving the pelletizer, are conveyed to 

stockpiles for cooling and storage. Most pellet products are transported to blast furnaces in the 

Great Lakes region by ships, which are loaded at Duluth, Silver Bay, Taconite Harbor, Escanaba, 

and Marquette at the shorelines of Lake Superior and Lake Michigan. Except for Northshore 

Mining Company, which is located on the shore of Lake Superior, the remaining taconite 

facilities use the railroad to transport their pellet products to the ports.

In the winter, the Great Lakes are closed, and most pellets are stockpiled on site at the facilities 

or at the docks to wait for the next shipping season. A portion of the pellets produced on the 

Mesabi Range is shipped by railroad trains to other locations, for which transportation is carried 

out all year round.

Simplification of Process Reference -- The process diagram for a taconite mining and processing 

facility can be simplified, for the purpose of estimating HAPs emissions, as “at-pellet firing” and 

“off-pellet firing” processes. For a grate-kiln pelletizer, drying and preheating of green balls in 

the grate, and pellet induration in the rotary kiln and the part of pellet coolers near the kiln are the 

“at-pellet firing” processes. Blasting in the mine pits, crude ore crushing, crushed ore grinding 

and concentrating, fired pellet cooling and handling (transfer, stockpiling, and loading out) are 

the “off-pellet firing” processes.

HAPs Emissions at Pellet Firing

Two categories of hazardous air pollutants (HAPs) are emitted from the pelletizer’s waste gas 

stack(s). The first is related to metal and non-metal elements naturally associated with taconite 

ore and other solid materials and fuels fed into the pelletizer. Emissions of most of these 

elements can be determined with stack testing using Reference Method 29 (manganese, arsenic, 

lead, nickel, chromium, selenium, antimony, cadmium, mercury, cobalt, and beryllium). 

Emissions of hydrogen chloride and hydrogen fluoride, or acid gases, also have been determined 

with stack testing.

The second category of HAPs emitted includes products of incomplete combustion (PICs), which 

are compounds in the gaseous state. Formaldehyde has been found through stack testing. 

Hexane, benzene, and toluene were found to be below respective detection limits, but are 

suspected to be present.
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HAPs Emissions from Off-Pellet Firing Processes

The blasting operation can be omitted for HAPs emission estimation, because, while blasting 

may be a very significant event on a short-term time scale, it does not cause any significant air 

quality impact on an hourly basis in the taconite mining area. Blasting is conducted one to three 

times a week, depending on the facility. The blasting methods and technologies currently used in 

the taconite mining industry include most, if not all, of the following: 1) engineering a blast hole 

pattern to minimize the amount of blasting agent used and maximize fragmentation, 2) stemming 

blast holes to direct energy release horizontally, 3) computerizing blast hole delay to further 

enhance fragmentation, and 4) conduct blasting only when local meteorological conditions are 

acceptable. Federal and state rules do not allow blasting, when there is a temperature inversion 

in the atmosphere or when wind conditions would, with blasting, create excessive air shock 

(overpressure).

Stack testing has not been conducted specifically for determining HAPs emissions from offpellet firing processes. However, chemical analysis has been performed on various materials for 

element composition. Assuming that the particulate matter (PM) emitted from the off-pellet 

firing processes has the same element composition as the feed to the processes, emissions of the 

Reference Method 29 elements can be estimated. Based on this assumption, PM emissions from 

off-pellet firing processes, available from Emission Inventory databases maintained at Minnesota 

Pollution Control Agency and from taconite facilities in Michigan, can be used for the HAPs 

emission estimation.

Preliminary review of HAPs emissions indicated that approximately 10% of the total facility

HAPs emissions could be attributed to off-pellet firing processes. This suggests that attention 

should be focused on the pelletizing process in HAPs emission estimation for the taconite ore 

mining and processing industry.

Part 2. Individual Facilities

Below is a brief description and history for individual taconite ore mining and processing 

facilities in Minnesota, in the descending order of production rates as shown in Table 2.

U.S. Steel Minnesota Ore Operations (Minntac)

Currently the largest taconite pellet producer in the U.S. with the latest reported plant capacity of 

15.3 million long tons (17.14 million tons) per year, the Minntac pelletizing facility was built in 

three successive steps. Becoming operational in October 1967, Step I consists of taconite 

processing lines (or agglomerator lines as called at Minntac) 1, 2, and 3, each of which is rated at 

2 million long tons of fired pellets per year (1 long ton is equal to 2240 lbs.). Step II was built in 

1972, consisting of lines 4 and 5. Step III was built in 1978, consisting of lines 6 and 7, which 

are capable of firing with coal at the rotary kiln (other lines were designed to burn natural gas and 

fuel oil). Each line of Step II and Step III is rated at 3 million long tons of fired pellets per year. 

Lines 1 and 2 are no longer operational. Thus, the original capacity estimate for the overall plant 

remains about 14 million long tons (15.68 million tons) per year, which is very close to the 

average annual production level (15.55 million tons) shown in Table 2. Due to continuing 
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process changes, the overall plant capacity can change from one year to the next in the taconite 

processing industry.

Over a period from 1987 to 1989, auxiliary burners were added to the traveling grate section of 

lines 3 through 7, achieving the capability of making fully fluxed pellets. During this period, 

main burners of Step II and Step III were modified to accommodate sawdust firing. Nearly 400 

emission units are listed in Minntac’s Part 70 permit application.

Mining

Minntac mines the crude ore with the current, conventional methods and technologies of the 

taconite mining industry. A significant distinction between Minntac and the other taconite mines 

is the practice of direct loading of rail transportation units (trains) instead of trucks in some parts 

of the mine. However, planning is under way to phase out the rail transport and to replace it 

completely with truck hauling.

Crushing

Minntac uses a three-stage crushing system. The first and second stages are single pass. A 

screen after each second stage and each third stage crusher sends the fine (minus 0.5 inch) 

material directly to the Concentrator. The third stage screen takes oversize material and returns it 

in closed circuit to the third stage crushers for further size reduction. A separate fluxstone 

(limestone and dolomite) unloading facility is located at the crushing plant for transferring the 

fluxstone from the common carrier railroad to the Concentrator.

Concentrating

Minntac’s concentrating process lines use a conventional three-stage grinding system, which 

consists of one rod mill and two ball mills. Each ball mill operates in closed circuit with a 

material classifier so that the oversize material returns to the ball mill until the optimum particle 

size is achieved. A magnetic separator follows each grinding mill to reject the non-iron bearing 

particles (tailings) from the grinding system. Finally, each grinding line uses fine screens to 

return any remaining large iron bearing particles to the second ball mill. Following the grinding 

and magnetic separation section, the concentrate is delivered to a flotation system for the final 

silica reduction. One grinding line is reserved for fluxstone grinding. The ground concentrate 

and the ground fluxstone slurries are delivered separately to the Agglomerator.

Agglomerating (Balling and Pelletizing)

The fluxstone slurry is metered into the concentrate slurry at a specific ratio. Following 

agglomeration in balling drums, five grate-kiln systems are used for indurating the pellets. 

Figures 5A and 5B show a schematic of the grate-kiln system at Minntac. Natural gas burners in 

the traveling grate preheat furnaces supplement the kiln burners for the total thermal requirement. 

Natural gas is the primary fuel in the kiln burners. Sawdust is co-fired with natural gas in three 

kilns. Pulverized coal is an alternative fuel in the two other kilns. Fuel oil No. 2 is an alternative 

in all five kilns. Waste gas stacks are equipped with a wet scrubber at Lines 4 through 7 and with 

“drop out boxes” (gravity collectors as indicated in Table 2) at Line 3. Heat recuperation is 

facilitated at Lines 4 through 7 to move hot air from the annular pellet cooler to the drying zone 

in the grate. Line 3 is not retrofitted with heat recuperation.
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Hibbing Taconite Company (HTC)

The latest plant capacity of HTC is reported as 8.0 million long tons (8.96 million tons) per year. 

HTC uses Dravo/Lurgi traveling grate pelletizing machines at its processing facility. Figure 3 is 

a schematic of such a pelletizer. HTC’s Lines 1 and 2 started up in 1976 with a total annual 

capacity of 5.4 million long tons of pellets. Line 3, with an initial annual capacity of 2.7 million 

long tons of pellets, was added in 1979, thus making the overall plant capacity of 8.1 million 

long tons (9.07 million tons) per year. Continuing improvements over the years may have 

increased the overall plant capacity to 8.3 million long tons of fired standard pellets (9.30 million 

tons) per year, which is very close to the average annual production level (9.19 million tons) 

shown in Table 2.

Mining

Over 56 million tons of material must be mined annually to provide crude ore for current pellet 

production at full capacity. HTC uses 170 and 240 ton capacity trucks to haul crude taconite ore 

from mine pits to the processing plant. Mining tasks consist of overburden removal, drilling, 

blasting, and removal of waste rock and crude taconite ore from the pits.

Rotary drills are used to bore 16” holes to a depth of about 55 feet. Less than one-half pound of 

explosives is used in blasting for each ton of broken taconite ore. In-pit crude ore loading is 

performed with 18 and 33 cubic yard shovels.

Crushing and Concentrating

Crude ore, containing about 20 percent magnetic iron, is delivered to two 60 × 109 inch gyratory

crushers for size reduction to 10 inch chunks, which are conveyed to a 450,000 ton capacity

stockpile. Unlike some other facilities, HTC uses this single stage crushing.

From the stockpile, crushed crude ore is conveyed into one of nine 36 foot diameter autogenous 

grinding mills, each of which is equipped with two 6,000 HP motors. Water is added and as the 

ore tumbles it reduces itself in size to 75 percent finer than 325 mesh (43 m). Autogenous 

grinding is now enhanced with use of pebble crushers. Following two stages of wet magnetic 

separation, without any flotation step, a concentrate averaging 66 percent iron is delivered to the 

pellet plant.

Pelletizing

In the pellet plant, the concentrate is thickened. Vacuum disc filters reduce the concentrate’s 

moisture content to 9 percent. About 10 pounds of bentonite clay is added to one ton of moist 

concentrate. Large rotating drums are used to roll the resultant material into “green balls.”

The unfired balls are next conveyed into one of three straight grate furnaces and heat hardened at 

about 2450 oF. The final product, a pellet averaging 66 percent iron, has physical characteristics 

such as size and durability that make it well suited for the iron making blast furnaces.

LTV Steel Mining Company (LTVSMC)
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With latest reported plant capacity at 8.0 million long tons (8.96 million tons) of standard pellets 

per year, the LTVSMC facility has operated on a continual basis since start-up in 1957. The 

average annual production, shown in Table 2, is 8.56 million tons. It is not unusual for a plant to 

produce more pellets in a year than originally expected (plant anticipated production rate is 

reported at the beginning of the year).

Founded as Erie Mining Company, LTVSMC was one of the first taconite production facilities 

on the Mesabi Range and in the iron mining industry as a whole. The pellet plant was expanded 

in 1967. LTVSMC ownership (including controlled-lease) includes approximately 65,000 acres 

(the largest track of land among taconite facilities in Minnesota), a company-owned railroad 

(approximately 74 miles in length to Taconite Harbor on Lake Superior), and a steam electric 

generating station and a dock facility at Taconite Harbor. LTVSMC remains a competitive 

taconite pellet producer, mainly because it generates its own electricity (slightly more than its 

own consumption), and it owns its railroad for transporting pellets to Lake Superior.

Mining

Millions of tons of overburden (rock and other surface material) must be removed before drilling 

and blasting can be performed. More than 28 million tons of magnetic crude ore are mined each 

year to meet current production needs. Holes of about 16 inches in diameter and 45 feet in depth 

are drilled into the taconite ore. Explosives are pumped into the holes, and blasts are fired to free 

the magnetic taconite ore.

Electric shovels with up to 33 cubic yard buckets load the crude ore into 170 and 240 ton haulage 

trucks, which transport the ore to loading pockets (including two Super Pockets), where it is 

transferred to 85 ton rail cars for transportation to the coarse crusher.

Crushing and Concentrating

In the first two stages of coarse crushing, crude ore is reduced from “run-of-mine” size to 6 inch 

size by 60 inch and 36 inch gyratory crushers. Two additional fine crushing stages use cone 

crushers to further reduce the material to about one inch. The crushed ore is then conveyed to the 

quarter-mile-long concentrator.

Rod mills are used to grind crushed ore to nominal size of less than 1⁄4”. Ball mills are used to 

further reduce it to pass 10 mesh. Magnetic separation, hydraulic classification and silica 

flotation are used to make final concentrate. Before concentrate slurry goes to the vacuum disc 

filters from the thickener, it is pumped to the heat exchanger on top of 12 pelletizing furnaces 

(Figure 7) to recover some heat in the pelletizer’s waste gas, or “top gas” as it is called at 

LTVSMC. As this report was being finalized, LTVSMC had agreed to add heat exchangers or 

auxiliary emission control equipment to the remaining 12 pelletizing furnaces.
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Pelletizing

In the pellet plant, the concentrate slurry is thickened and vacuum filtered. The resultant 

concentrate, with about 10 percent moisture and 67 percent iron, is mixed with bentonite clay and

rolled into “green balls” in balling drums.

The green balls are charged at the top and descend through 24 vertical shaft furnaces, as shown in 

Figure 4, where they are heat hardened at 2350 oF. Discharged pellets are screened and 

transferred on conveyor belts to stockpiles for cooling prior to shipping.

All 24 furnaces are equipped with a multiclone for primary cleaning of top gas. The retrofit for 

heat recuperation of top gas of 12 furnaces (Figure 7), which resulted in lower particulate 

emissions, is like a spray tower except that the scrubbing media is not pure liquid but taconite 

concentrate slurry. About 25 percent of the total air enters the furnace through the hot-gas inlet 

around 2350 oF. Pellets in this zone of the furnace reach temperatures of 2400 oF or higher due 

to the exothermic conversion from magnetite to hematite. The remaining 75 percent of the 

furnace air enters via the cooling-air inlet. Discharged pellets are at about 700 oF, and top gas 

temperature is below 400 oF before it reaches the multiclone.

EVTAC Mining, LLC

On December 1, 1996, EVTAC, a recently established Minnesota limited liability company, 

acquired the Thunderbird Mine and Fairlane Plant facilities from Eveleth Mines, a partnership. 

EVTAC and Northshore are the only two companies that have the pelletizing facility apart from 

the mining facility. The Thunderbird Mine is located at Eveleth. The Fairlane Plant is located 

near Forbes, 10 miles south of the Thunderbird Mine. Railroads, one of which is ten miles long 

and the other twelve miles long, connect the two separate facilities.

The facilities were built in 1965 with the Fairlane plant having one pelletizer capable of making 

1.7 million long tons (1.90 million tons) of fired standard pellets per year. Production capacity

was expanded in 1976 with installation of another pelletizer capable of making 3.7 million long 

tons (4.14 million tons) of fired standard pellets per year. The overall plant capacity is 5.4 

million long tons (6.05 million tons) per year. The average annual production, shown in Table 2, 

is 5.69 million tons. It appears that the concentrator is the bottleneck for the overall plant 

production.

On February 15 1999, EVTAC decided to idle Line 1 by May 31, 1999, and to focus on 

continuing and enhancing taconite pellet production with Line 2. This action was similar to the 

one taken by National Steel Pellet Company in January 1980. Based on published production 

data from 1995 through 1997, Line 1 made about 45% of the pellets Line 2 did, while Line 2 

consumed about 45% of the energy Line 1 did. Being an old line, Line 1 is not retrofitted for 

heat recuperation. With Line 1 shut down, the latest plant capacity is reported as 3.5 million long 

tons (3.92 million tons) per year.
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Mining and Coarse Crushing

Taconite ore can be mined from the North and South Mines, though the South mine has been 

inactive for more than 5 years. The mining operations include the removal of overburden 

material, removal of waste rock material, and the mining of taconite ore. Crude taconite ore is 

loaded onto trucks and hauled to either the North or South Crusher (also inactive the past 5 years) 

areas for primary and secondary crushing. Crushed ore is then loaded onto railcars and 

transported to the Fairlane Pant for further processing.

Fine Crushing and Concentrating

Fine crushing is performed with third and fourth stage crushers at Fairlane Plant. Coarse tailings 

are hauled away by trucks and used as construction material for the tailings basin sidewalls. Fine 

tailings are pumped in slurry form to the tailings basin. Grinding and magnetic separation are 

wet operations. Flotation is not used at EVTAC.

Pelletizing

At the pellet plant, the concentrate is mixed with various additives to produce a mixture, which 

can be formed into green balls in a balling drum. For many years, EVTAC has used organic 

binders as an alternative to bentonite clay. There are five balling lines upstream of Line 1 

pelletizer (“etco,” as it was referred to in old documents) and seven balling lines upstream of 

Line 2 pelletizer (“exco”).

EVTAC uses the grate-kiln pelletizers. Line 1 pelletizer is fired with natural gas. Line 2 can be 

fired with coal-petroleum coke blend fuel or natural gas. Like other taconite facilities, fuel oil is 

used as backup fuel, when there is a natural gas curtailment during the winter. Waste gas stacks 

of Lines 1 and 2 are cleaned with venturi wet scrubbers, not venturi-rod wet scrubbers commonly

used in other taconite facilities.

National Steel Pellet Company (NSPC)

In August 1997, NSPC became the first taconite mining and processing company to receive a 

Title V permit. The permit authorizes operations of Phase II equipment and a portion of the 

Phase I equipment. NSPC has received MPCA approval for a fugitive emission control plan and 

an operation and maintenance plan for its air pollution control equipment.

NSPC is a wholly-owned subsidiary of National Steel Corporation. The current company

structure emerged after a year-long Company lockout from August 1, 1993 through late in 

August 1994. Employees, now also owners of the company, participate in NSPC’s decision 

making process.

Phase I of the NSPC facility started up in June 1967, with a rotary hearth pelletizing process, 

which had never been tried before. After many months of unsuccessful operation, a more 

conventional grate-kiln system was installed (the period for construction was from September 

1968 to March 1969). In 1977, Phase II expansion added another grate-kiln system. Phase I

pelletizer was shut down in January 1980 and written off in 1983, according to Skillings Mining 

Review (July 25, 1998).
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NSPC has shown its ability to operate a grate-kiln pelletizer well above design capacity, based on 

production data from 1967 through 1998. The maximum annual production for the Phase I, 

reached in 1971 (the second full calendar year after the grate-kiln system’s installation), was 2.81 

million long tons (3.15 million tons) of fired standard pellets. The maximum annual production 

for Phase II, reached in 1998, was 5.29 million long tons (5.92 million tons) of fired partially

fluxed pellets. This is an increase of 88 percent from the annual production of Phase II in 1979 

(the second full calendar year after the installation of Line 2), which can be estimated as about 

2.81 million long tons (3.15 million tons) of fired standard pellets. NSPC is well known in the 

taconite industry for repeatedly achieving annual, single-line production records. The latest plant 

capacity is reported as 5.3 million long tons (5.94 million tons) per year.

Mining

Mining activities include overburden removal, drilling, blasting, and removal of waste rock and 

crude taconite ore. NSPC blasts waste rock one to five times per year and crude ore once per 

week during daylight hours. Crude ore is hauled by trucks to the primary crushers.

Crushing and Concentrating

Similar to HTC, NSPC crushes crude ore in a single stage. Chunks of crude ore as large as 5 feet 

are reduced to 6 inches in size or smaller by one of the two gyratory crushers.

Crushed ore, minus six inches in size, is charged with forged steel balls, into 7 or 8 of 10 

grinding lines, each equipped with a 27-ft diameter wet semi-autogenous grinding (SAG) mills 

and Derrick screens, that are active at any one time. When reduced to about the consistency of 

sand, the material is drawn out of the mills as a slurry. The remaining part of the concentrating 

circuit includes cyclones, hydroseparators, wet magnetic separators, ball mills, and screens. 

Flotation is not used at NSPC.

Pelletizing

In the pellet plant, about 16,000 long tons (near 18,000 tons) of pellets are made daily.

After the dewatering step with vacuum disc filters, the concentrate (filter cake) is added to 

bentonite clay, or an alternative binder, and other additives such as fluxstone. The moist, solid 

material forms “soft” or “green” pellets in any one of the eight balling drums (12’ in diameter 

and 33’ in length). NSPC is permitted to make semi-fluxed pellets with fluxstone content up to 

1.5 percent by weight. Fired pellets are screened to remove fine particles.

Phase II pelletizer is fired with natural gas as the primary fuel and distillate oil as the backup fuel. 

Each of the two waste gas stacks is equipped with a multiclone.

Northshore Mining Company (NMC)

NMC, formerly known as Reserve Mining Company, operates a taconite mine at Babbitt and a 

processing plant at Silver Bay. A 47-mile rail road links the mine to the plant (Figure 1). The 

Silver Bay plant is the oldest one in the U.S. taconite processing industry. Furnaces 1 through 6 
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were built in 1954 (Table 2), each of which was designed to make about 1 million long tons of 

pelleters per year. Furnaces 11 and 12 (manufactured by Arthur G. McKee Company, second 

generation of straight grate furnaces) were built in 1962, each of which was designed to make 2 

million long tons of pellets per year. The tailings basin (“Mile Post 7”) was designed to handle 

the 10 million long ton production level.

The latest plant capacity, with Lines 6, 11, and 12 in active production, is reported as 4.7 million 

long tons (5.26 million tons) per year. The first load of taconite pellets was shipped out of the 

plant on September 13, 1956. Figure 8 shows the history of NMC’s pellet production.

In the 1970s, federal and state court decisions made the Reserve Mining Company change some 

of its production practices. Lake dumping of tailings was changed to on-land disposal at Mile 

Post 7, and most air pollution control measures at the Silver Bay plant were upgraded. Then, 

Furnaces 1 through 4 were shut down in 1981 (and removed in 1998), and Furnaces 5 and 6 were 

shut down in 1982. In 1986, Reserve filed for bankruptcy. Cyprus Amax Minerals Company

was the successful bidder for the Reserve assets.

Cyprus Northshore Mining Corp. resumed pellet production in 1990. In June 1995, Furnace 6 

returned to production to supplement Furnaces 11 and 12. On June 30, 1994, Cleveland-Cliffs 

purchased Cyprus Northshore Mining Corp. and renamed it Northshore Mining Company. 

NMC’s existing mining and processing operations are summarized in Figure 9. The reader can 

compare it to Figure 6 to learn from different process designs.

Since 1998, NMC has proposed to replace the idle, yet still permitted Furnace 5, with a pig iron 

production line. The proposed project, already submitted for environmental review, consists of 

raw material handling processes, two Rotary Reduction Furnaces (RRFs), one Submerged Arc 

Furnace (SAF), three off-gas conditioners (boilers, one for each furnace), and product handling 

processes. NMC is calling the project its direct reduced iron (DRI) project.

Mining

In the Reserve years, much of the overburden at the Babbitt Mine was removed. After blasting, 

crude ore is truck hauled to the coarse crushers for primary and secondary crushing. Crushed 

crude ore is transported by railcars to the Silver Bay plant for subsequent crushing and further 

processing.

Crushing and Concentrating

As mentioned at the beginning of this Package, the type of magnetic taconite near NMC’s 

Babbitt Mine and LTVSMC’s facility is different from others on the Mesabi Range. According 

to NMC, the crude ore is harder at the eastern part of the Mesabi Range than at the western part, 

demanding more energy in crushing and grinding for NMC. Dry cobbers (dry magnetic 

separators) were added as an additional removal step.

At the concentrator, rod mills and ball mills are used for fine grinding. Each grinding step is 

followed with magnetic separation. The concentrating process ends with an amine flotation step.
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Pelletizing

NMC is the only taconite plant that makes fully fluxed pellets (FFP, Table 2) without the need to 

add auxiliary burners to the pelletizer (straight grate type). Fluxstone content in the fired pellets 

is about 4.95% at NMC, compared to 8.15% at U.S. Steel Minntac and 10.7% at Ispat-Inland 

Steel Mining Company.

Furnaces 11 and 12 have been retrofitted with heat recuperation. Being older, Furnace 6 does not 

have heat recuperation. Unlike HTC’s pelletizers (Figure 3), each of NMC’s Furnaces 11 and 12 

have two common headers, one of which is connected to three hood exhaust stacks, and the other 

is connected to two waste gas stacks. All five pelletizer stacks are outfitted with wet wall 

electrostatic precipitators (WWESPs).

Ispat-Inland Steel Mining Company

Formerly known as Inland Steel Mining Company or the Minorca Mine, the facility received its 

present name just before January 1, 1999. Ispat-Inland is the smallest taconite pellet producer in 

the U.S. taconite industry with one straight grate pelletizer. However, it does make fully fluxed 

taconite pellets (Table 2). The latest plant capacity is reported as 2.8 million long tons (3.14 

million tons) per year.

Mining

After overburden and rock are stripped and trucked to stockpiles, taconite ore is drilled, blasted, 

and trucked to the processing plant. Unlike other facilities which have a complex system of 

haulage roads, Ispat-Inland has one 9 mile long, unpaved haulage road linking the mining areas 

to the processing plant.

Crushing and Concentrating

Taconite ore is crushed to football size chunks in the primary crusher and moved by conveyor 

belt to an intermediate stockpile. Fine ore results from second and third stage crushing. Then 

rod and ball mills grind the fine ore to face powder size to facilitate magnetic separation of ironbearing particles from waste material (tailings).

Balling

Different from other facilities, Ispat-Inland uses balling discs, rather than balling drums, to make 

green balls from moist concentrate. Discs take much less space than drums do. However, they

present a challenge in size control of green balls (unfired pellets). Fluxstone (limestone and/or 

dolomite) is crushed and ground. It is then mixed with taconite concentrate and a binding agent. 

It is rolled into marble size green balls with the balling discs.

Pelletizing

Pellets are heat-hardened at 2400 oF in a straight grate furnace fired with natural gas (distillate 

fuel oil is used as a backup fuel). Originally, Ispat-Inland’s pelletizer was very similar to the 

pelletizers used at Hibbing Taconite Company (Figure 3). In order to make fully fluxed pellets, 

the pre-heating zone was modified to add auxiliary burners. All four stacks of the pelletizer are 

controlled with wet scrubbers.
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Package 2

EMISSIONS OF HAZARDOUS AIR POLLUTANTS AND PM10

FROM U.S. TACONITE IRON ORE INDUSTRY

Existing emission testing results, material composition data, pellet production, and indurating 

fuel usage data from the seven companies in Minnesota establish a broad information base for 

emission estimates presented in this package. The two companies in Michigan also provided 

relevant process and emission information. See Table 3 for a summary description of past testing 

of the taconite facilities.

Based on calculations made with existing information, each of the nine U.S. taconite mining and 

processing facilities emits more than 25 tons of all hazardous air pollutants (HAPs) combined, as 

shown in Table 4. This information was shared with all parties -- industry representatives, 

consultants, and staff of the Minnesota Pollution Control Agency (MPCA), Michigan 

Department of Environmental Quality (MDEQ), and the United States Environmental Protection 

Agency (EPA) -- at meetings and/or telephone conferences. It was also made available to local 

government representatives and the general public.

Current air pollution control measures, which have been used primarily for PM emission control, 

have some widely different effects on HAPs emissions from taconite ore mining and processing 

facilities. For acid gases such as HCl and HF, wet control devices such as wet wall electrostatic 

precipitators and venturi-rod wet scrubbers have the capability of reducing HCl and HF 

emissions substantially, if the pH of the scrubbing liquid is maintained properly. In an 

engineering test at Northshore in January 1992, control efficiency for HCl or HF was determined 

to vary from 74% for one run to 97% for another run. Dry control devices such as multiclones 

and gravity collectors can be assumed to have no control of acid gas emissions. This is 

supported in part by the August 1999 engineering test conducted at National Steel Pellet 

Company. It is well known and verified by the testing summarized herein that venturi-rod wet 

scrubbers and ESPs – wet or dry type – are more effective and efficient than multiclones and 

gravity collectors for PM emission control.

Products of incomplete combustion (PICs) such as formaldehyde, benzene, toluene, and hexane 

do not appear to be affected by current air pollution control devices. Volatile elements such as 

mercury, arsenic, selenium and cadmium have shown a more complex picture on control 

equipment effects.

Although boiling point temperatures for the volatile elements in pure substance (or element) 

form are lower than the peak gas stream temperature in the pelletizer (2400 oF), they are higher 

than the waste gas temperature at the stack (from 100 to 300 oF). Past testing of one straight 

grate and three grate-kiln pelletizers showed the following: more than 96 percent of the mercury

captured with the Method 29 sampling train was found in the “back half,” more than 90 percent 

of the arsenic captured was found in the “front half,” cadmium captured in the “front half” 

ranged from 52 through 86 percent, and selenium captured in the “front half” ranged from 75 
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through 90 percent. This suggests that mercury is likely emitted in the vapor phase (“elemental 

mercury”), while arsenic, cadmium, and selenium are likely emitted with particulate matter (PM).

Some of the current PM/PM10 emission control measures can be considered as effective 

surrogate control measures for more than 95 percent, by weight, of the elements for Reference 

Method 29. This estimate is based on a preliminary level of review of the data and the following 

assumptions: 1) only mercury and selenium are emitted in the vapor phase and all other Method 

29 elements are emitted as PM; and 2) past Method 29 testing results are representative of 

current pelletizing operations.

For this reason, stack testing results for emissions of particulate matter (PM) and particulate 

matter of 10 m or smaller (PM10) have been reviewed. Figures 10 through 12 show controlled 

PM10 or PM emissions (individual run data) associated with wet scrubbers, electrostatic 

precipitators, and multiclones for the taconite pellet indurating process. (Data for Line 3 of U.S. 

Steel Minntac are placed in Figure 12, even though its waste gas stack is equipped only with 

“drop boxes,” instead of a multiclone. The drop boxes are also called gravity collectors, as 

shown in Table 2.) The curves plotted in Figures 10 through 12 represent Minnesota’s PM rule 

and are used as a benchmark. In general, if the average data point from a three-run test is below 

the curve in either one of the charts (a) and (b), the test is concluded to be in compliance with the 

PM rule. Table 5 provided the complete concentration data presented in chart (b) of Figures 10 

through 12.

It should be noted that the benchmarks are not meant to suggest a particular formulation for 

emission limits, which may be used for the taconite MACT standard. It should also be pointed 

out, that Northshore Mining Company’s processing plant is subject to modeling based PM 

emission limits for all stacks, which are more stringent than the Minnesota’s PM rule. The air 

quality dispersion modeling was performed in the permitting process to authorize the resumption 

of pellet production at NMC’s plant in 1990.

The MPCA has been working with the facilities that use grate-kiln pelletizers (U.S. Steel 

Minntac, EVTAC, and National Steel Pellet Company) to bring the cooler vent stack PM 

emissions into compliance with the state’s PM rule. The original designer of the process 

equipment did not incorporate installation of any dust collector for the vent stack of the annular 

pellet cooler. Current operational practices (fully fluxed pellet production, alternative binders, 

and/or increased production rate) appear to have increased the PM emissions from this stack.

For the remaining part of Package 2, information will be presented for individual facilities in the 

following order. 1) If HAPs emission factors have been derived from a facility’s own stack 

testing, a summary of the HAPs testing results will be presented. 2) If material composition has 

been analyzed for a facility, a summary of the analysis will be presented. 3) HAPs emission 

estimates will be presented, whether emission factors are source-specific or derived from HAPs 

testing elsewhere in the industry. 4) PM10 or PM testing results in recent years will be presented.

Of all HAPs, mercury is the most tested one. All nine taconite facilities have conducted mercury

emission testing at the pelletizer waste gas stack(s). Some facilities tested twice or three times. 
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Some facilities also performed a mercury mass balance for the pelletizing process to compare 

with the stack testing results. Mercury analysis of materials was also reported by most facilities 

in Minnesota. Many of these voluntary efforts in Minnesota were made in the wake of a report to 

the Minnesota Pollution Control Agency for Minnesota legislators on the mercury atmospheric 

emission from the state’s taconite pellet production (CMRL industry report, dated September, 

1997). As of October 1999, the MPCA has provided the EPA three mercury mass balance 

reports (including the CMRL industry report) and nine mercury stack test reports (including one 

for the speciated mercury testing conducted at Hibbing Taconite Company from September 29 

through October 2, 1998).

As indicated in Package 1, mineral fibers (iron amphiboles – grunerite, cummingtonite, actinolite 

– and others) are found in ore deposits on the Mesabi Range east of Aurora (Figure 1 & Table 1). 

The Clean Air Act, as amended, lists “fine mineral fibers” as a hazardous air pollutant in Section 

112 (b)(1). However, it is not clear if the amphibole fibers found at the eastern end of the Mesabi

Range fall under the federal definition of fine mineral fibers, as far as regulatory applicability is 

concerned. Public concerns on potential health implications of mineral fibers have largely been 

associated with Northshore Mining Company, especially its proposed new taconite ore 

processing technology – direct reduced iron (DRI).

DRI, including other variants of this technology, have been suggested as a way to add value to 

the current taconite concentrate pelletizing technology. In addition to the proposed DRI project 

by Northshore Mining Company, a new steel mill -- incorporating taconite mining and 

processing and direct reduction technology (Minnesota Iron and Steel Company) has commenced 

the first stages of environmental review (Minnesota Department of Natural Resources is the 

responsible government unit). Inland Steel Mining Company and National Steel Pellet Company

have proposed their own DRI projects over the last few years but failed to get corporate funding.

U.S. Steel Minnesota Ore Operations (Minntac)

Minntac has made great efforts to generate its own mercury emission estimate for the pelletizing 

process. The CMRL report’s mercury mass balance study was followed with an improved mass 

balance study by the CMRL staff and concurrent stack testing using Reference Method 29 for 

mercury. The resultant mercury emission estimate is used where appropriate.

As shown in Table 3, Minntac has not conducted stack testing for any other HAP. The total 

HAPs emission estimate, of 342 tons of HAPs per year as shown in Table 4, is attributed mainly

to the use of emission factors generated from other taconite facilities. Table 6 details HAPs 

emission estimates for pellet firing processes. Table 7 details HAPs emission estimates for offpellet firing processes.

Figure 5B shows the gas and pellet flows of the grate-kiln system at Minntac. For grate-kiln 

system of higher capacity (for example, EVTAC’s Line 2 or NSPC’s Phase II), the waste gas 

stream is split into two, side-by-side, stacks.
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The emission estimate for hydrogen chloride (HCl), in Table 6, needs some explanation. 

Fluxstone has been suggested as the major source of chlorine (Cl) to the pelletizer. One would 

suspect taconite ore as another possible source of chlorine. For pelletizers which have wet 

control devices for the waste gas stream, the following linear regression equation can be used to 

estimate controlled emissions of HCl.

EHCl = 0.00448 + 0.09407  Rfluxstone [1]

Where EHCl is the predicted controlled emission factor, lb HCl/ton pellets fired;

Rfluxstone is the mass fraction of fluxstone in the fired taconite pellet.

Figure 13 is a graph of the equation and the data points resulting from four stack tests. The 

regression model has an R2value of 0.591 and an adjusted R2value of 0.386. The slope has a pvalue of 0.231. The intercept has a p-value of 0.332. Statistically, equation [1] is not a good fit 

because of limited stack testing data. An alternative HCl emission estimation method would be 

to use an EHCl value of 0.01776 lb HCl/ton pellets fired, obtained from stack testing at Inland in 

June 1997. This alternative method would lead to a slightly inflated emission estimate for 

Minntac and very significant over-estimations for other facilities that do not have the high 

fluxstone usage that Inland has.

For pelletizers which have dry control devices for the waste gas stream such as Minntac’s Line 3, 

HCl emission estimate can be made with results of stack testing conducted at National Steel 

Pellet Company in August 1999, 0.03096 lb HCl/ton pellets fired.

The emission estimates for “metals” (the elements determined with Reference Method 29) atpelletizing, shown in Table 6, need some further clarification. While most metal emission 

factors have been developed from stack testing conducted at pelletizers that are equipped with 

wet control devices, additional metal emission factors have been generated from the August 1999 

stack testing at National Steel Pellet Company, which uses dry control devices (multiclones) for 

waste gas cleaning. For Minntac’s Lines 4 through 7, metal emission estimates are calculated 

with the emission factors associated with wet control devices. Metal emission estimates for Line 

3 are calculated with the emission factors developed from the NSPC stack testing results.

Table 7 also deserves some discussion. As stated in Package 1, for off-pellet firing processes, the 

PM emitted into the air is assumed to have the same element composition as the feed, so that 

emissions can be estimated by multiplying the PM emissions by the proper composition data. 

Since the available element composition data is limited to several solid materials, PM emissions, 

obtained from the MPCA’s Emission Inventory, are divided into several groups (for example, 

ore, bentonite, greenballs, fired pellets, and fluxstone unit processes). Since Minntac does not 

report composition data, for each group, composition data available from other mines are 

averaged and used for emission estimation for the off-pellet firing processes at Minntac.

The data in Table 7 show that PM emissions for off-pellet firing processes vary widely from one 

facility to another, and from one year to the next for the same facility. There are reasons for 

these variations. PM emissions are no longer used to calculate emission fees, thus they are not 
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verified by MPCA staff. In addition, MPCA staff made some policy changes during 1995-1997 

regarding reported efficiency values for air pollution control devices for the Emission Inventory. 

Regardless of emission fee calculation and allowed control efficiency values in reporting, 

facilities such as Minntac that use three or four stage ore crushing circuits generally emit more 

PM than those using one stage ore crushing for that part of the overall ore processing operation.

From the three annual sums of element emission estimates (1995, 1996, and 1997) in Table 7, the 

median value, 24.9 ton HAPs/year of 1995, is selected as the total HAPs emission estimate for 

off-pellet firing processes at Minntac. This is less than the “metals” emission estimate from the 

pelletizers, 54.6 ton/year, in Tables 4 and 6.

It should be emphasized that, except for mercury, HAPs emissions may have been over-estimated 

for Minntac. This, however, follows the conservative conventions in regulatory applicability

determination, when there is little source-specific emission information.

Finally, source-specific stack testing results of PM10 emissions at the pelletizers’ waste gas stacks 

are presented in Table 8. (The data in Table 8 reflect “total catch,” which consists of “front 

half” and “back half.”) The information in this table has been used in Figures 10 and 12 as well 

as Table 5, in a general discussion of potential HAPs emission control by means of controlling a 

surrogate air pollutant. The reader is reminded that Minntac’s Lines 4 through 7 are equipped 

with venturi-rod wet scrubbers to control particulate emissions from each waste gas stack, and 

Line 3 is equipped with only “drop boxes” (gravity collectors, as called in Table 2) for particulate 

emission control at the waste gas stack.

Reference Method 5, which is for PM sampling at point sources, is used at Minntac’s Lines 4 

through 7 to provide, in the MPCA’s view, a conservative estimate of the “dry catch” or “front 

half” data for PM10. The MPCA’s view is based on a recent testing study conducted by a testing 

company for the MPCA on particulate matter testing methods at selected emission sources 

including a taconite pelletizer. Reference Method 202 is used to assess the “condensibles” or 

“back half” data. These two methods generated PM10 emission estimates for Lines 4 through 7 

with adequate data quality. Since Line 3 does not have as good a control device as a venturi-rod 

wet scrubber, Reference Method 201A was used, instead of Method 5, to get a realistic estimate 

of the “dry catch” or “front half” data for PM10. The reader will find similar situations later in 

the tabulated PM10 data of LTV Steel Mining Company and National Steel Pellet Company.

Hibbing Taconite Company (HTC)

HTC is one of the best tested facilities in the industry, as shown in Table 3. Emissions of 

mercury and other metals were determined by Braun Intertec during June 1994 performance test 

using Reference Method 29 (Table 9). HTC also analyzed the composition of some solid 

materials related to taconite pellet production (Table 10). MPCA staff has just completed a 

review of a speciated mercury emission study done for HTC by the University of North Dakota 

Energy & Environmental Research Center (the testing period was from September 29 to October 

2, 1998).
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The resultant emission factors for total mercury emissions are close to each other, with 12.4 

nanogram of mercury per gram of pellets fired (ng/g) from the 1998 test and 11.4 ng/g from the 

1994 test. The mass ratio of ng/g in SI units is equivalent to “parts of mercury per 1 billion parts 

of pellets fired, by weight (ppbw),” which should not be confused with a concentration unit of 

“parts of a pollutant per 1 billion parts of fluid, by volume (ppbv).” Furthermore, “ppb” is used 

in this report for the mass ratio expressed in “ppbw,” to simplify presentation in the text and the 

tables.

Test runs were from 120 to 150 minutes for the 1998 test, and 60 minutes for the 1994 test. All 

four stacks of Line 2 were tested in 1998, while two of the four stacks of Line 1 were tested in 

1994. The 1998 test found that greater than 94 percent of the mercury emitted from the stacks 

were in element form (Hg0), with the remaining part as oxidized mercury (Hg2+) and very little 

bound with particulate matter. Assessment of mercury control efficiency of the venturi-rod wet 

scrubbers was attempted during the 1998 test by sampling at the two inlet ducts of the common 

exhaust header, in addition to the sampling of the four stacks. An estimate of 20 to 30 percent 

was made for the control efficiency of total mercury. This, however, should be used with 

caution, because a scientifically acceptable assessment on mercury control efficiency requires six 

sampling trains be placed for simultaneous sampling at the four stacks and the two inlet ducts. 

The 1994 test did not involve any inlet sampling.

Stack testing for the products of incomplete combustion (PICs), hydrogen chloride (HCl), and 

hydrogen fluoride (HF) was conducted at HTC, although the detection limits in chemical analysis 

were higher than desired for this review for some pollutants (Table 11). The HCl emission data 

contributed to the linear regression model, equation [1] and Figure 13, which made it possible to 

estimate HCl emissions from some untested facilities.

With all the underlying source-specific information, HAPs emissions estimates for HTC may be 

of the highest quality for the entire taconite mining and processing industry. Table 12 shows 

HAPs emission estimates for at-pellet firing processes. Table 13 summarizes HAPs emission 

estimates for off-pellet firing processes. The total HAPs emission estimate for HTC, as shown in 

Table 4, is 32.6 ton per year. This is the lowest HAPs emission estimate among the nine taconite 

ore processing facilities in the U.S. Still, it is greater than the threshold value of 25 tons per year 

for a major HAPs emission source. Thus, all taconite ore processing facilities in the U.S. should 

be considered as major sources for HAPs emissions.

PM emission testing was done thoroughly at all three pelletizers at HTC in 1994 using Reference 

Methods 5 and 202. Since all pelletizer stacks were controlled with wet scrubbers, the testing 

results provide conservative estimates for PM10 emissions. Line 2 was again tested in July 1999. 

Table 14 presents the testing results.

As shown in Figure 3, straight grate pelletizers have at least four stacks. Sometimes, a straight 

grate facility would choose to conduct stack testing at some of the stacks in order to save testing 

cost. However, HTC often conducted stack testing at all four stacks. Since stack variation is 

different from one pollutant to another, HTC’s approach of testing all stacks has been required 

for compliance testing and should be encouraged for voluntary testing.
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LTV Steel Mining Company (LTVSMC)

LTVSMC participated in the 1997 CMRL industry study for mercury atmospheric emissions 

using a mass balance approach. The MPCA review of the study report suggested an emission 

factor of 1.91 ppb by weight of pellets produced for mercury emissions from the vertical-shaft 

furnace top gas. The emission factor was the average value of 2.25 ppb calculated for a furnace 

without heat recuperation and 1.58 ppb calculated for a furnace with heat recuperation. Direct 

stack testing at the furnace without heat recuperation, conducted on April 15, 1998, resulted in an 

emission factor of 4.33 ppb.

LTVSMC has conducted stack testing for benzene, toluene, hexane, and formaldehyde (Table 

15). Among the three taconite facilities, which conducted stack testing for these products of 

incomplete combustion (PICs), LTVSMC used the lowest detection limits in the chemical 

analysis. No stack testing was conducted for the elements of Reference Method 29 (“metals”), 

hydrogen chloride, or hydrogen fluoride.

Table 16 shows HAPs emission estimates for LTVSMC’s taconite pelletizers. Notice that, like 

in Table 6 for U.S. Steel Minntac, the metals emissions are calculated with different emission 

factors, depending on whether a wet control device is used for waste gas cleaning. Recall that all 

24 pelletizers are equipped with a multiclone for top gas cleaning, 12 of which are added with a 

heat exchange (concentrate slurry scrubbing), somewhat similar to wet scrubbing. Metals 

emission estimates for off-pellet firing processes are given in Table 17. The total HAPs emission 

estimate for LTVSMC, summarized in Table 4, is 169 ton per year.

PM10 emission testing results at LTVSMC’s pelletizers’ top gas stacks are shown in Table 18. 

The information in this table has been used in Figures 10 and 12 as well as Table 5.

As indicated in Package 1, mineral fibers (iron amphiboles – grunerite, cummingtonite, actinolite 

– and others) are found in ore deposits on the Mesabi Range east of Aurora (Figure 1 & Table 1). 

LTVSMC and NMC’s Babbitt Mine are in this area. LTVSMC closed its Dunka mine, which is 

east of Babbitt and known to contain mineral fibers; however, fibers are also found in ore from 

LTVSMC’s eastern mining areas.
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EVTAC Mining, LLC

Emission rates of mercury and other elements were determined through stack testing using 

Reference Method 29 at EVTAC’s Fairlane Plant in 1997. At the same time, the Coleraine 

Minerals Research Laboratory performed a mercury mass balance study. Mercury emission 

factor from stack testing is 11.16 ppb by weight of pellets fired, compared to 10.48 ppb from the 

CMRL study. These values are the average of both pelletizer lines. Table 19 gives the stack 

testing results. Table 20 shows some composition data provided by EVTAC.

No stack testing was conducted at EVTAC for benzene, toluene, hexane, formaldehyde, 

hydrogen chloride, or hydrogen fluoride. Highest values of relevant emission factors from other 

taconite facilities were used. HAPs emission estimates for the pelletizers are shown in Table 21. 

Notice that metals emission estimates are calculated from line-specific emission factors, shown 

in Table 19, weighted with line production data. HAPs emission estimates for off-pellet firing 

processes are summarized in Table 22. The total HAPs emission estimate for EVTAC, 

summarized in Table 4, is 74.9 ton per year.

PM testing results with Reference Methods 5 and 202 are given in Table 23, as conservative 

estimates of PM10 emissions. The information has been used in Figure 10 and Table 5. As noted 

previously, Line 1 has one waste gas stack and Line 2 has two, side-by-side waste gas stacks. 

Figure 5(b) shows the relative location of the waste gas stacks to the rest of the grate-kiln system.

National Steel Pellet Company (NSPC)

NSPC is the facility that has done the most recent HAPs testing. The August 1999 stack testing 

results are summarized in Table 24. Because NSPC uses dry control (multiclones) for waste gas 

cleaning, acid gas (HCl and HF) emissions are very high, while other HAPs emissions are low 

(Tables 25) due to the use of source-specific emission factors. Table 26 provides estimates of 

HAPs emissions from off-pellet firing processes. The total HAPs emission estimate for NSPC, 

summarized in Table 4, is 248 ton per year.

NSPC has conducted stack testing for PM10 emissions from one of the two pelletizer’s side-byside waste gas stacks using Reference Methods 201A and 202. Testing results are given in Table 

27. The information has been used in Figure 12 and Table 5.

Northshore Mining Company (NMC)

Because the processing plant is on the shore of Lake Superior with a state highway (Minnesota 

Highway 61) running through the middle of the plant as well as its past practice of tailings 

disposal in Lake Superior, NMC has been under public scrutiny for many years. The recent DRI

proposal has renewed public attention, especially with the issues of emissions of fine mineral 

fibers and mercury.

While the stack testing and ambient monitoring results of mineral fibers generated by Northshore 

are of limited use to the other taconite companies in the U.S., NMC has conducted three stack 
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tests for metals (mercury and others) emissions using Reference Method 29 and generated useful 

composition data for various materials. Table 28 shows Reference Method 29 testing results at 

NMC’s pelletizers. Table 29 summarizes composition data from NMC. It should be noted that 

metals testing was also conducted at gas stream inlets (common exhaust headers) during each 

stack test to assess collection efficiency of air pollution control equipment. However, because of 

data quality problems, inlet testing or collection efficiency of metals are not presented in this 

Package. (These subjects, especially mercury, are among the most important ones for the 

proposed DRI project; a complete analysis on control equipment performance for mercury 

emissions should include the gas stream, liquid stream, and the captured solid stream -- NMC 

uses “wet-walled EPSs.”)

NMC and Hibbing Taconite Company are the two taconite companies that generated their own 

HAPs emission information (emission factors and material composition data). As indicated 

before, each of NMC’s Furnaces 11 and 12 have two common exhaust headers, one of which is 

connected to the three hood exhaust stacks, and the other is connected to the two waste gas 

stacks. Typically, NMC would conduct stack testing at one of the three exhaust hood stacks and 

one of the two waste gas stacks. Additional stacks were sometimes probed for flow distribution 

only. It also should be noted here that, inlet sampling for collection efficiency assessment at 

NMC’s Furnace 11 or 12 is more likely to succeed at the hood exhaust common header than at 

the waste gas common header, based on the flow balance seen in recent testing results. The 

problem may be attributed to inlet turbulence.

Table 30 shows stack testing for formaldehyde, benzene, toluene, and hexane, all products of 

incomplete combustion (PICs). Table 31 shows stack testing for hydrogen chloride (HCl) and 

hydrogen fluoride (HF). The hydrogen chloride emission data from NMC serve as the two data 

points in the middle of the chart of Figure 13, making it possible to generate a linear regression 

model for predicting HCl emissions from the untested taconite facilities.

Table 32 summarizes HAPs emission estimates for the pelletizers at NMC. Table 33 gives HAPs 

emission estimates from off-pellet firing processes. The total HAPs emission estimate for NMC, 

summarized in Table 4, is 78.6 ton per year.

Table 34 provides stack testing results for PM emissions (Reference Methods 5 and 202 or a 

Minnesota method for “back half” -- organic wet catch). It should be noted that NMC’s 

operating permit has an emission limit of 0.01 gr/dscf for PM at the pelletizer stacks, which are 

controlled with wet walled electrostatic precipitators (WWESPs). This is more stringent than the 

state’s PM rule (Minn.R. 7011.0735).

Ispat-Inland Steel Mining Company

Ispat-Inland has not tested for emissions of products of incomplete combustion (benzene, 

toluene, hexane, and formaldehyde). However, stack test information for other HAPs, PM, and 

PM10 can be found in two testing reports.
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In June 1997, Inland conducted a voluntary test at all four stacks of the pelletizer for emissions of 

hydrogen chloride (HCl), hydrogen fluoride (HF), and PM10. Table 35 shows testing results from 

the test.

In July 1994, Inland conducted an engineering test at Stack D, one of the four stacks of the 

pelletizer, for emissions of multiple metals, PM, hydrogen chloride (HCL) and fluorides. The 

reader is reminded of the previous discussion (last paragraph in the section for Hibbing Taconite

Company), in which testing all four stacks would be preferred. Table 36 summarizes the testing 

results. Table 37 shows composition data of samples of ore composite, green balls, and fired 

fluxed pellets.

Stack D is one of the two “windbox exhaust” stacks at the “hot side” of the common exhaust 

header (Figure 3). Thus, company personnel considers it the dirtiest stack. Whether the 

information in Tables 35 and 36 justifies such labeling is subject to each individual’s opinion. 

For this reason, emission factors for HCl and fluorides in Table 36 are used in subsequent 

emission estimation calculations (Tables 38 and 39).

With the HCl emission data (of HTC, NMC, and Ispat-Inland shown in Tables 11, 31, and 37) 

the detail of linear regression model analysis -- equation [1], which has been shown in Figure 13 

-- can be presented, as in Table 38. Please recall that the resultant equation can be used only for 

pelletizers with wet control devices for waste gas cleaning. For pelletizers with dry control 

devices, the August 1999stack testing results from National Steel Pellet Company should be 

used, instead.

Table 39 gives HAPs emission estimates from Ispat-Inland’s pelletizer. Table 40 summarizes 

HAPs emission estimates for off-pellet firing processes. The total HAPs emission estimate for 

Ispat-Inland, summarized in Table 4, is 52.3 ton per year.
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Package 3: Bibliography, Tables & Figures

Bibliography

1. Lankford, William T., Jr.; Samways, Norman L.; Craven, Robert F.; McGannon, Harold E. 

(Editors). The making, shaping and treating of steel. 10th edition. United States Steel. 

1985 Association of Iron and Steel Engineers.

2. Skillings, David N. North American iron ore industry. Skillings’ Mining Review, last weekly

issue in July, 1996, 1997, and 1998.

3. Agglomeration special short course. Society of Mining, Metallurgy and Exploration (SME) 

Minnesota Chapter, Duluth, MN, April 13, 1999.

4. Jiang, Hongming; Wu, Chun Yi; Biewen, Todd. “Metals emissions from taconite ore 

processing facilities in Minnesota.” A paper presented at Emission Inventory: Living in a 

Global Environment, an international symposium organized by Air & Waste Management 

Association, December 8-10, 1998, New Orleans, Louisiana. (Mr. David Z. Skolasinski, of 

Cliffs Mining Services Company provided Hongming Jiang with the industry’s comments in 

his letters dated November 17 and November 20, 1998. The comments were received after 

the paper was finalized.)

5. Potts, Raymond D. Induration of taconite pellets using grate-kiln system at Minntac. 

Skillings’ Mining Review, August 17, 1991.

6. Minnesota Pollution Control Agency Air Emission Inventory Database. Reports for 1995 

through 1997 provide detailed indurating fuel usage and particulate matter (PM) emission 

data for the seven taconite companies.

7. Jiang, Hongming. Personal communication with the nine companies on fluxstone usage in 

taconite pelletizing process. January-February 1999.

8. Jiang, Hongming. Personal communication with Dennis Wagner on the designed capacities 

of the pelletizers and the fluxstone contents for the hydrogen chloride stack testing in 1992 

and 1998 at Northshore Mining Company. September 1999.

9. Jiang, Hongming. Personal communication with Gustav Josephson on the fluxstone content 

for the hydrogen chloride stack testing in 1997 at Inland Steel Mining Company. September 

1999.

10. Engesser, John; Niles, Harlan B. Mercury emissions from taconite pellet production. A 

report submitted to the Minnesota Pollution Control Agency from Coleraine Minerals 

Research Laboratory (CMRL), Natural Resources Research Institute, University of Minnesota

Duluth, September 1997.

11. Jiang, Hongming. Mercury atmospheric emissions from taconite pelletizing process. An 

office memorandum to Edward Swain, Ph.D., Multimedia Integration Unit, Environmental 

Research and Reporting Section, Environmental Outcomes Division, Minnesota Pollution 

Control Agency, September 15, 1998.
MPCA Report

Page 28

12. Jiang, Hongming. Ambient air monitoring for mineral fibers near Northshroe Mining 

Company: How to evaluate the concentration data from statistical perspectives? An office 

memorandum to interested parties. February 26, 1999.

13. Direct reduced iron (DRI) modification: Documentation of emission calculations. Prepared 

for Northshore Mining Company by Barr Engineering Company. October 1998.

14. Morey, Glenn B. Chemical composition of the eastern Biwabik iron-formation (early

Proterozoic), Mesabi Range, Minnesota. Economic Geology, 1992, 87, 1649-1658.

15. Morey, Glenn B.; Lively, R.S. Background levels of mercury and arsenic in paleoproterozoic 

rocks of the Mesabi Iron Range, northern Minnesota. Minnesota Geological Survey, 

Information Circular 43. University of Minnesota, St. Paul, 1999. Web site: 

http://www.geo.umn.edu/mgs.

16. Air toxics: Hazardous emissions from coal combustion. Clean Coal Today (a newsletter 

about innovative technologies for coal utilization). U.S. Department of Energy, Office of 

Fossil Energy. Issue No. 25, Spring 1997. DOE/FE-0215P-25.

17. Moore, Michael P. A timeline of Minnesota’s iron ore industry. An exhibit presented at a 

conference sponsored by the University of Minnesota, February 28 and March 1, 1995. 

University of Minnesota Office or Research and Technology Transfer.

18. Interpoll Laboratories. Results of the MPCA particulate and PM10 comparative evaluation 

study. Prepared for Stuart Arkley, Minnesota Pollution Control Agency. Report Number 9-

12423. June 14, 1999.

19. Bartlett, Robert V. The Reserve Mining Controversy: Science, Technology, and 

Environmental Quality. Indiana University Press, 1980.

20. Bastow, Thomas F. “This Vast Pollution...” United States of America v. Reserve Mining 

Company. Green Fields Books, Washington, DC. 1986.

21. Weiss, Norman L. (Editor). SME Mineral Processing Handbook. Volume 2. Section 20 

(Iron Ore). Published by Society of Mining Engineers of the American Institute of Mining, 

Metallurgical, and Petroleum Engineers, Inc. New York, NY. 1985.

22. U.S. Environmental Protection Agency. Compilation of Air Pollutant Emission Factors. AP42, fifth edition. Volume I: Stationary Point and Area Sources. Section 11.23. 1995.

23. Guthrie, George D.; Mossman, Brooke T. (Editors). Health Effects of Mineral Dusts. 

Review in Mineralogy, Volume 28. Mineralogical Society of America. 1993.
MPCA Report

Page 29

Table 1. U.S. Taconite Iron Ore Facility Location*

State Company Mine Pelletizing Plant

Minnesota National Steel Pellet Company Keewatin

Hibbing Taconite Company Hibbing

U.S. Steel Minnesota Ore 

Operations (Minntac)

Mt. Iron

EVTAC Mining, LLC Eveleth Forbes

Ispat-Inland Steel Mining Co. Virginia

LTV Steel Mining Company Hoyt Lakes

Northshore Mining Company Babbitt Silver Bay

Michigan Tilden Mining Company, LC Ishpeming

Empire Iron Mining Partnership Palmer

* Companies from top down are listed in the order of the westernmost to the easternmost.
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Table 2. U.S. Taconite Iron Ore Industry Profile1

Company Production,2

106tons/yr

Pelletizer

Type

Year(s) Built Primary 

Product3

Second. 

Prod.4

Process Chemicals 

Used5

Emission Control for 

Waste Gas Stacks6

Energy Used,7

106 Btu/ton

Primary Fuel Secondary 

Fuel

USS Minntac 15.55 Grate-kiln 1967

1972

1978

SP, FFP DS,

Flot, SM,

Frz

1 unit: GC

2 units: WS

2 units: GC-WS

0.560 Natural gas 

and/or 

Gas/Sawdust

Coal at Lines 

6&7; fuel oil at 

others

Hibbing Tac 9.19 Grate 1976, 1979 SP Frz 3 units: WS 0.277 Natural gas Fuel oil #2/#6

Empire 9.11 Grate-kiln 63, 66, 75, 80 SP, FFP Flot, Filt 4 units: DESP 0.482 Natural gas Coal

LTV 8.56 Vertical 

shaft

57, 62, 67 SP PC Flot, CA,

Filt

15 units: M

12 units: M-WS

0.459 Natural gas Fuel oil #6

Tilden 7.06 Grate-kiln 1974

1978

SP, FFP Flot 2 units: DESP 0.589 Natural gas Coal

EVTAC 5.69 Grate-kiln 1965

1976

SP, PFP PC DS, WS, CA,

SM, Frz

2 units: WS 0.499 Natural gas & 

coal/coke

Fuel oil

National 5.65 Grate-kiln 1967, 1977 SP, PFP SM 2 units: M 0.386 Natural gas Fuel oil

Northshore 4.52 Grate 1954, 1962 SP, PFP, FFP PC Flot, CA, Filt 4 units: WESP 0.668 Natural gas Fuel oil

Ispat-Inland 3.02 Grate 1976 SP, FFP PC DS, Flot, CA, Filt 1 unit: WS 0.474 Natural gas Fuel oil

Total 68.35

Footnotes: 1. Except for the data on production and energy used, the information in this table was provided by David Z. Skolasinski, Chair, Taconite Industry MACT Work 

Group, April 9, 1999.

2. Average production data of 1995 through 1997, as published in Skillings Mining Review, a trade journal. The average production of 7.06 million tons per year 

for Tilden in this period consisted of 5.04 million tons of hematite FFP per year, 2.02 million tons of magnetite FFP per year, and no SP.

3. SP is for standard pellets (no fluxing additives); FFP is for fully fluxed pellets (greater than 1.0 basicity ratio); PFP is for partially fluxed pellets (equal to or 

less than 1.0 basicity ratio).

4. PC is for pellet chips, a substitute for iron ore sinter feed.

5. Chemicals listed here are not merely limited to the pelletizing process. DS is for dust suppressants; Flot is for flotation process chemicals; SM is for slag 

modifier agents; Frz is for freeze conditioning agents; Filt is for filtration enhancement chemicals; CA is for chemical agglomeration agents; WS is for water 

softeners.

6. This column lists air pollution control equipment for the waste gas stacks. Dash between symbols means control equipment in series. M is for multiclone(s); 

WS is for wet scrubbers; DESP is for dry electrostatic precipitators; WESP is for wet electrostatic precipitators; GC is for gravity collectors (“drop boxes”). 

Although 15 units are listed here with symbol M for LTV, only 12 units were involved in production in recent years. Pelletizers with multiclone or drop box 

control contribute to less than 15% of the entire industry’s production, based on average data from 1995 through 1997. This includes 8.3% from National Steel 

Pellet Company’s Phase II (multiclones), 4.2% from the 12 LTV units (multiclones), and 2.4% from USS Line 3 (drop boxes).

7. This is a simplified, annual indurating energy consumption normalized to annual production based on average data from 1995 to 1997. Detailed data on pellet 

product types, fuel types, or specific lines used are not reflected in this column. The column is for a facility level overview of the indurating energy usage only. 

The data for Empire and Tilden were for one recent year, not averaged from 1995 to 1997.
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Table 3. Taconite facilities: HAPs emission testing status

Pelletizer 

type; % ind. 

production1

Facility; % 

industry 

production

Tested for 

PICs? 2

Tested for HCl 

and HF?

Tested for 

Metals?

3

Tested for 

mercury?

Grate-kiln; US Steel; 22.8% No No No Yes

63.0% of all Empire (MI); 13.3% Yes No Yes Yes

facilities’ Tilden (MI); 10.3% No No Yes Yes

production EVTAC; 8.32% No No Yes Yes

National; 8.27% Yes Yes Yes Yes

Straight- Hib Tac; 13.4% Yes Yes Yes Yes

grate; 24.5% Northshroe; 6.62% Yes Yes Yes Yes

Ispat-Inland; 4.42% No Yes Yes Yes

Verticalshaft; 12.5% LTV; 12.5% Yes No No Yes

Sum: 100% 100% --- --- --- ---

1. Production data for 1995 – 1997 are taken from Skillings Mining Review, a trade journal.

2. Products of incomplete combustion, which include the four compounds – formaldehyde (HCHO), benzene, 

toluene, and hexane – that were suspected to be present in the pelletizer’s waste gas stream.

3. These are metal and non-metal elements emitted from the pelletizer’s waste gas stack(s), which are determined 

using Reference Method 29 – Antimony (Sb), Arsenic (As), Beryllium (Be), Cadmium (Cd), Chromium (Cr), 

Cobalt (Co), Lead (Pb), Manganese (Mn), Mercury (Hg), Nickel (Ni), and Selenium (Se). All the tested 

facilities in Minnesota also reported element composition information for concentrate, fired pellets, coal, etc.
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Table 4. HAPs emission estimates for regulatory applicability determination1(unit: ton/yr)

Facility HF HCl2 HCHO3

3 PICs 4 Metals @o5 Metals @p6 Total HAPs

National 158 87.5 0.780 0.605 1.13 4.03 252

Northshore 12.7 17.4 32.9 4.57 8.38 2.61 78.5

Hibbing 1.81 18.1 1.34 8.18 0.136 3.04 32.6

Ispat-Inland 3.82 26.8 15.6 4.60 0.532 0.980 52.3

LTV 95.3 56.7 1.33 3.79 11.7 5.58 174

EVTAC 16.0 14.6 30.8 9.10 2.72 1.59 74.8

U.S. Steel 84.7 110 94.6 27.9 24.9 9.84 352

Empire (MI) 12.2 30.3 2.20 1.85 0.948 0.932 48.4

Tilden (MI) 9.45 30.8 2.55 1.45 0.455 0.826 45.5

Sum 394 392 182 62.1 50.9 29.4 1110

Rank 35% 35% 16% 6% 5% 3% 100%

1. This table is an integral part of Package 2 and should be used along with the text of Package 2. Emission 

estimates were calculated for a facility using its own testing data. If it does not have HAPs testing data, the 

worst values of the testing data from other facilities are used to calculate the emission estimates.

2. Chlorine (Cl) is thought to come from fluxstone and taconite ore. A linear regression model of HCl emissions 

on fluxstone content was developed from stack testing data. The model was used to estimate HCl emissions 

from pelletizers at untested pelletizers with wet control for waste gas cleaning. For those with dry control, 

results from an August 1999 stack test at National Steel Pellet Company should be used, instead.

3. Formaldehyde, one of the four products of incomplete combustion (PICs).

4. The three other PICs are benzene, toluene, and hexane. All were found below detection limits, but were 

suspected to be present.

5. These are estimates of the emissions of the Reference Method 29 elements for off-pellet firing processes. They 

were calculated from PM emissions reported to the state’s emission inventory and available element 

composition data. No attempt was made to verify the reported PM emissions.

6. These are elements emitted from the pelletizer’s waste gas stack(s), which are determined using Reference 

Method 29 – Antimony (Sb), Arsenic (As), Beryllium (Be), Cadmium (Cd), Chromium (Cr), Cobalt (Co), Lead 

(Pb), Manganese (Mn), Mercury (Hg), Nickel (Ni), and Selenium (Se). Symbol “<” (less than) is used, because 

some of the elements were found below detection limits in emission testing.
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Table 5. Concentration data from existing stack testing results 1

Gas flow, 

dscfm

Loading, 

gr/dscf

Gas flow, 

dscfm

Loading, 

gr/dscf

Gas flow, 

dscfm

Loading, 

gr/dscf

Gas flow, 

dscfm

Loading, 

gr/dscf

Wet scrubbers PM10 control performance – data points plotted in Figure 11(b)

116900 0.0140 140700 0.0090 151700 0.0130 282378 0.0071

117600 0.0089 141327 0.0071 152300 0.0054 283006 0.0067

118800 0.0090 141400 0.0077 153700 0.0054 283687 0.0076

124500 0.0037 143473 0.0107 153800 0.0181 291402 0.0185

125200 0.0050 143700 0.0132 156800 0.0101 295241 0.0177

126200 0.0056 144600 0.0027 158600 0.0098 296681 0.0171

126200 0.0025 144634 0.0076 159700 0.0149 298179 0.0216

126300 0.0074 144969 0.0100 160000 0.0085 305001 0.0216

129400 0.0059 145207 0.0147 163800 0.0123 305961 0.0213

131700 0.0137 145900 0.0079 164700 0.0057 309551 0.0181

132700 0.0052 146700 0.0045 165400 0.0072 323559 0.0194

136300 0.0039 146900 0.0168 170600 0.0101 348649 0.0145

136700 0.0053 147135 0.0198 171300 0.0108 433690 0.0085

137000 0.0080 148009 0.0196 174200 0.0075 452410 0.0095

137000 0.0053 148200 0.0122 175000 0.0127 452858 0.0110

137200 0.0084 149200 0.0064 175200 0.0071 456712 0.0106

138928 0.0074 149200 0.0134 176000 0.0082 463696 0.0091

139000 0.0038 149600 0.0071 179000 0.0117 464145 0.0112

139500 0.0056 150321 0.0092 270438 0.0129 469552 0.0112

140090 0.0075 150400 0.0132 270920 0.0092 471755 0.0074

140600 0.0102 151200 0.0085 271351 0.0118 486968 0.0118

Electrostatic precipitators’ PM control performance – data points plotted in Figure 12(b)

52507 0.0095 61671 0.0366 63698 0.0093 72787 0.0107

52937 0.0091 61752 0.0458 63717 0.0093 73133 0.0075

52961 0.0062 61764 0.0059 63727 0.0079 73739 0.0094

56129 0.0069 61812 0.0104 64551 0.0398 268604 0.0067

56134 0.0068 61825 0.0101 65952 0.0100 304507 0.0089

56746 0.0055 62059 0.0275 66236 0.08222307235 0.0124

58484 0.0087 62062 0.0073 68343 0.0093 309457 0.0149

60125 0.0066 62176 0.0118 69067 0.0089 310075 0.0158

60661 0.0064 62321 0.0085 69343 0.0118 311932 0.0038

60740 0.0064 62512 0.0062 69427 0.0243 315844 0.0084

60998 0.0058 62573 0.0065 69437 0.0062 318262 0.0057

61258 0.0309 62729 0.0324 70134 0.0114 527086 0.0066

61312 0.0052 63577 0.0097 70315 0.0102 527779 0.0028

61536 0.0099 63698 0.0077 71070 0.0303

1. The benchmark PM concentration curve, also plotted in charts (b) of Figures 10 through 12, is generated from 

(gr/dscf) = 1.76 (dscfm)-0.324. Minn.R. 7011.0735 also specifies 0.100 gr/dscf for 7000 dscfm or less, and 0.020 

gr/dscf for 1000000 dscfm or more. Tabulated in this table are individual run data.

2. This is the only data point that is above the benchmark PM curve. See Figure 12(b).
MPCA Report

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Table 5. Concentration data from existing stack testing results 1(Continued)

Gas flow, 

dscfm

Loading, 

gr/dscf

Gas flow, 

dscfm

Loading, 

gr/dscf

Gas flow, 

dscfm

Loading, 

gr/dscf

Gas flow, 

dscfm

Loading, 

gr/dscf

Multiclones’ PM10 control performance (no enhancement) – data points “+” in Figure 13(b)

46945 0.0704 57296 0.1220 254977 0.0227 303314 0.0769

49099 0.0707 242840 0.0281 255129 0.0246 323362 0.0740

50134 0.1068 243330 0.0278 257601 0.1942 324473 0.0718

51599 0.0571 244830 0.0214 257654 0.1501 356930 0.3974

52410 0.0691 247815 0.0438 259967 0.2047 362663 0.2849

54388 0.1212 251145 0.0266 299513 0.0574

55806 0.0689 252076 0.0322 300352 0.0554

56772 0.0628 253275 0.0385 300650 0.0547

Multiclones’ PM10 control performance (with enhancement) – data points “” in Figure 13(b)

35542 0.0817 37513 0.0889 38691 0.0952 45663 0.0311

36713 0.0768 38074 0.0277 39047 0.0271 46059 0.0169

37221 0.0456 38340 0.0384 40362 0.0195 46934 0.0150

1. The benchmark PM concentration curve, also plotted in charts (b) of Figures 10 through 12, is generated from 

(gr/dscf) = 1.76 (dscfm)-0.324. Minn.R. 7011.0735 also specifies 0.100 gr/dscf for 7000 dscfm or less, and 0.020 

gr/dscf for 1000000 dscfm or more. Tabulated in this table are individual run data. Data for gravity collectors 

(“drop boxes”), used at Line 3 of U.S. Steel Minntac, are lumped with the multiclone data for convenience.
MPCA Report

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Table 6. HAPs emission estimates for Minntac’s taconite pelletizers 1

Pollutant Emission, 

ton/year

Emission 

factor

E.F. unit Emission factor source

Products of incomplete combustion based on annual heat input of 8,702,767 MMBtu/yr

Benzene < 8.98 < 0.00206 lb/MMBtu HTC 7/96

Toluene < 9.98 < 0.00229 lb/MMBtu HTC 7/96

Hexane < 8.98 < 0.00206 lb/MMBtu HTC 7/96

Formaldehyde 94.6 0.02173 lb/MMBtu NMC 10/95

Emissions which are related to production level--15,554,268 ton pellets/year & 8.15% fluxstone usage

Hydrogen chloride 110 From regression equation2and NSPC 8/99

Hydrogen fluoride 84.7 0.00562 lb/ton pel. NMC 1/92; NSPC 8/99

Metals at-pellet firing 3 Emission 

factor

E.F. unit Emission factor source

Antimony, Sb <0.189 < 13.3 ppb pellets Ispat-Inland 94

Arsenic, As 3.20 208 ppb pellets EVTAC L2 97

Beryllium, Be < 0.018 < 1.26 ppb pellets NMC 94

Cadmium, Cd 0.038 2.68 ppb pellets Ispat-Inland 94

Chromium, Cr 1.02 67.0 ppb pellets NMC 5/98

Cobalt, Co < 0.025 < 1.40 ppb pellets EVTAC L1 97

Lead, Pb 2.09 147 ppb pellets Ispat-Inland 94

Manganese, Mn 2.06 107 ppb pellets Ispat-Inland 94

Mercury, Hg 0.082 From direct stack testing & mass balance study

Nickel, Ni 0.837 57.2 ppb pellets EVTAC L2 97

Selenium, Se 0.271 13.5 ppb pellets NMC 5/98

1. The algebraic symbol, “<” (less than), indicates that the emission factor was developed from a stack 

test for which the mass recovered was below the detection limit for that air pollutant.

2. See equation [1] in the Package 2 text, which is applied to Lines 4 through 7 (venturi-rod wet 

scrubber controlled pelletizers). HCl emission factor from National Steel Pellet Company, 0.03096 

lb/ton pellets fired, is applied to Line 3 (dry control – drop boxes or “gravity collectors,” Table 2).

3. Reference Method 29 is the stack testing method for the elements listed here. Two sets of emission 

factors are used. Listed here is the first set (for example, less than 13.3 parts of antimony in weight 

per 1 billion parts of pellets fired), which was applied to Lines 4 through 7. The second set, also in 

units of ppb of pellets fired, is taken from the August 1999 stack testing at National Steel Pellet 

Company (see Table 24). The second set of emission factors was applied to Line 3. About 89.5% 

of pellets are produced from Lines 4 through 7 from 1995 to 1997.
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Table 7. HAPs emission estimation for off-pellet firing processes at Minntac 1

Process group2 Ore Bentonite Greenballs Fired pellets Fluxstone Ore Bentonite Greenballs Fired pellets Fluxstone Year total

Year PM from Emission Inventory,3ton/year Sum of element emissions for process groups, ton/year 

1995 4269 24.6 1088 1619 139 22.2 0.013 1.04 1.64 0.029 24.9

1996 3453 18.1 651 1595 106 18.0 0.010 0.623 1.61 0.022 20.2

1997 12611 26.3 1599 6756 261 65.6 0.014 1.53 6.83 0.053 74.0

Element Composition of elements, ppm by weight Individual element emissions, ton/year ‘95; sum:

4

Antimony, Sb 8.07 1.00 4.41 0.414 0.417 3.44E-02 2.47E-05 4.80E-03 6.70E-04 5.81E-05 4.00E-02

Arsenic, As 14.7 3.31 12.1 4.88 3.60 6.28E-02 8.15E-05 1.31E-02 7.91E-03 5.02E-04 8.44E-02

Beryllium, Be 2.12 2.25 0.420 0.742 0.230 9.04E-03 5.55E-05 4.57E-04 1.20E-03 3.21E-05 1.08E-02

Cadmium, Cd 1.05 0.233 0.280 0.028 0.050 4.48E-03 5.74E-06 3.05E-04 4.53E-05 6.97E-06 4.84E-03

Chromium, Cr 23.5 5.80 24.2 23.6 2.27 1.00E-01 1.43E-04 2.64E-02 3.82E-02 3.16E-04 1.65E-01

Cobalt, Co 10.0 3.23 3.83 7.06 0.67 4.25E-02 7.96E-05 4.17E-03 1.14E-02 9.30E-05 5.82E-02

Lead, Pb 13.1 34.4 2.53 0.580 1.97 5.61E-02 8.47E-04 2.76E-03 9.39E-04 2.74E-04 6.09E-02

Manganese, Mn 5107 479 903 968 193 2.18E+01 1.18E-02 9.83E-01 1.57E+00 2.70E-02 2.44E+01

Mercury, Hg 5.06 0.012 0.130 0.002 0.007 2.16E-02 2.98E-07 1.41E-04 3.24E-06 9.76E-07 2.17E-02

Nickel, Ni 7.04 5.83 3.43 5.64 2.00 3.01E-02 1.44E-04 3.73E-03 9.13E-03 2.79E-04 4.33E-02

Selenium, Se 10.8 0.267 3.53 0.280 0.233 4.61E-02 6.56E-06 3.84E-03 4.53E-04 3.25E-05 5.04E-02

Data source 5(a) (b) (c) (d) (e)

1. Since average composition data are used (see footnote 4 below), tracking of values of below detection limits is difficult. Thus, the algebraic symbol “<”, which is used in 

Table 6 (see footnote 1 of Table 6), is omitted.

2. Process group is used here to simplify data presentation. The ore group includes coarse and fine crushing. The fired pellets group includes pellet stockpiling & loadout.

3. PM emissions, reported to the Emission Inventory, are not verified by MPCA staff.

4. Sum of element emissions in 1995 for off-pellet firing processes is presented in Table 4. Individual element emissions for 1996 or 1997 are omitted to save space. All 

calculations were made using spreadsheets.

5. Composition data listed in this table are the average values reported by non-Minntac facilities. (a) For the ore group, the composition data are provided by Northshore Mining, 

Hibbing Taconite, Ispat-Inland, EVTAC, and Minnesota Geological Survey. (b) For the bentonite group, the composition data are provided by Northshore Mining and 

Hibbing Taconite. (c) For the greenballs group, the composition data are provided by Northshore Mining, Hibbing Taconite, and Ispat-Inland. (d) For the fired pellets group, 

the composition data are provided by Northshore Mining, Hibbing Taconite, Ispat-Inland, and EVTAC. (e) For the fluxstone group, the composition data are provided by 

Northshore Mining and Hibbing Taconite.
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Table 8. PM10 stack testing results for Minntac’s pelletizers 1

Line 5 (Methods 5 & 202; 9/4/97)2 Run 1 Run 2 Run 3 Average

Mass recovered, ug 36700 30100 25000 30600

Sample gas volume, dscf 51.63 41.44 34.47 42.51

Stack gas flow, dscfm 452858 469552 464145 462185

Isokinetic variation, % 93.9 99.0 99.9 97.6

Stack emission, lb/hr 42.58 45.11 44.53 44.07

Concentration, gr/dscf 0.01097 0.01121 0.01119 0.01112

Feed, long ton/hour 526 523 513 521

Pellets, long ton/hour 395 392 385 391

Line emission factor, lb/ton pellets fired 0.09637 0.10269 0.10333 0.10080

Notes: Stack gas flow has been corrected as per Minntac letter of 5/25/99; this is an 

engineering test; MPCA review letter is dated 10/29/97.

Line 7 (Methods 5 & 202; 9/3/97) Run 1 Run 2 Run 3 Average

Mass recovered, ug 60400 59000 48000 55800

Sample gas volume, dscf 43.20 46.84 50.97 47.00

Stack gas flow, dscfm 298179 323559 348649 323462

Isokinetic variation, % 98.3 98.2 99.2 98.6

Stack emission, lb/hr 55.15 53.91 43.43 50.83

Concentration, gr/dscf 0.02158 0.01944 0.01453 0.01852

Feed, long ton/hour 530 531 531 531

Pellets, long ton/hour 398 398 398 398

Line emission factor, lb/ton pellets fired 0.12387 0.12086 0.09737 0.11403

Notes: This is an engineering test, reviewed by MPCA (10/29/97).

Line 5 (Methods 5 & Minn.R.; 4/28/93) Run 1 Run 2 Run 3 Average

Mass recovered, ug 20800 21000 24200 22000

Sample gas volume, dscf 33.89 35.80 35.08 34.92

Stack gas flow, dscfm 452410 463696 456712 457606

Isokinetic variation, % 97.7 100.7 100.1 99.5

Stack emission, lb/hr 36.73 35.98 41.68 38.13

Concentration, gr/dscf 0.00947 0.00905 0.01065 0.00972

Feed, long ton/hour 488 462 476 475

Pellets, long ton/hour 366 347 357 357

Line emission factor, lb/ton pellets fired 0.08960 0.09271 0.10423 0.09551

Notes: The PM part of the test is complied (conc.) with state’s PM rule (MPCA, 2/16/94).

1. Feed-to-pellets conversion is assumed to be 0.75.

2. Method 5 is for “front half” or “dry catch” for PM. It is often used to get a conservative 

estimate for PM10 emissions at wet scrubber or ESP controlled waste gas stacks (Lines 4 

through 7), where Method 201A (the reference method for dry catch of PM10) cannot be 

used due to high moisture content of the gas stream. Method 202 is for “back half” or the 

condensibles. In the past, “back half” was sometimes analyzed as per Minn. R. 7005.0500, 

and the result was termed “organic wet catch.”
MPCA Report

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Table 8. PM10 stack testing results for Minntac’s pelletizers 1(Continued)

Line 4 (Methods 5 & Minn.R.; 4/27/93)2 Run 1 Run 2 Run 3 Average

Mass recovered, ug 30100 28300 17200 25200

Sample gas volume, dscf 54.83 37.02 35.96 42.60

Stack gas flow, dscfm 433690 486968 471755 464138

Isokinetic variation, % 97.5 99.1 99.4 98.7

Stack emission, lb/hr 31.49 49.24 29.85 36.86

Concentration, gr/dscf 0.00847 0.01180 0.00738 0.00922

Feed, long ton/hour 505 495 495 498

Pellets, long ton/hour 379 371 371 374

Line emission factor, lb/ton pellets fired 0.07424 0.11843 0.07178 0.08815

Notes: The PM part of the test is complied (conc.) with state’s PM rule (MPCA, 2/16/94).

Line 3 (Methods 201A & 202; 6/16/98)3 Run 1 Run 2 Run 3 Average

Mass recovered, ug 440300 321900 446800 403000

Sample gas volume, dscf 34.99 33.10 33.68 33.92

Stack gas flow, dscfm 257601 257654 259967 258407

Isokinetic variation, % 104.7 105.0 104.5 104.7

Stack emission, lb/hr 428.8 331.4 456.2 405.5

Concentration, gr/dscf 0.19419 0.15008 0.20473 0.18300

Feed, long ton/hour 282 282 283 282

Pellets, long ton/hour 212 212 212 212

Line emission factor, lb/ton pellets fired 1.8101 1.3992 1.9190 1.7095

Notes: This is a voluntary test, reviewed by MPCA (9/22/98). Fluxed pellets were made.

Line 3 (Methods 201A & 202; 3/25/94) Run 1 Run 2 Run 3 Average

Mass recovered, ug 160500 154500 144700 153233

Sample gas volume, dscf 33.47 31.00 31.10 31.86

Stack gas flow, dscfm 323362 303314 324473 317050

Isokinetic variation, % 87.1 94.6 85.7 89.1

Stack emission, lb/hr 205.1 200.0 199.7 201.6

Concentration, gr/dscf 0.07400 0.07691 0.07180 0.07424

Feed, long ton/hour 311 313 318 314

Pellets, long ton/hour 233 235 239 236

Line emission factor, lb/ton pellets fired 0.78515 0.76054 0.74759 0.76443

Notes: This is an engineering test, not reviewed by MPCA. Standard pellets were made.

1. Feed-to-pellets conversion is assumed to be 0.75.

2. Method 5 is for “front half” or “dry catch” for PM. It is often used to get a conservative 

estimate for PM10 emissions at wet scrubber or ESP controlled waste gas stacks (Lines 4 

through 7), where Method 201A (the reference method for dry catch of PM10) cannot be 

used due to high moisture content of the gas stream. Method 202 is for “back half” or the 

condensibles. In the past, “back half” was sometimes analyzed as per Minn. R. 7005.0500, 

and the result was termed “organic wet catch.”

3. The waste gas stack at Line 3 is controlled with gravity collectors (see Table 2).
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Table 8. PM10 stack testing results for Minntac’s pelletizers 1(Continued)

Ln.3 (Meth's 201A & Minn.R.; 6/23/93)2 Run 1 Run 2 Average

Mass recovered, ug 425000 295200 360100

Sample gas volume, dscf 23.02 11.47 17.24

Stack gas flow, dscfm 362663 356930 359797

Isokinetic variation, % 98.8 100 99.4

Stack emission, lb/hr 886 1216 1051

Concentration, gr/dscf 0.28492 0.39735 0.34113

Feed, long ton/hour 306 302 304

Pellets, long ton/hour 230 227 228

Line emission factor, lb/ton pellets fired 3.4457 4.7921 4.1189

Notes: This is a contractor study - no MPCA review. Fluxed pellets were made.

Line 3 (Methods 201A & 202; 4/27/93) Run 1 Run 2 Run 3 Average

Mass recovered, ug 118000 109700 116000 114567

Sample gas volume, dscf 32.87 30.93 31.20 31.67

Stack gas flow, dscfm 300352 300650 299513 300172

Isokinetic variation, % 97.7 95.5 94.7 96.0

Stack emission, lb/hr 142.6 141.1 147.3 143.7

Concentration, gr/dscf 0.05540 0.05473 0.05738 0.05584

Feed, long ton/hour 292 289 293 291

Pellets, long ton/hour 219 217 220 219

Line emission factor, lb/ton pellets fired 0.58148 0.58103 0.59849 0.58700

Notes: This is an engineering test, not reviewed by MPCA. Fluxed pellets were made.

1. Feed-to-pellets conversion is assumed to be 0.75.

1. Method 5 is for “front half” or “dry catch” for PM. It is often used to get a conservative 

estimate for PM10 emissions at wet scrubber or ESP controlled waste gas stacks, where 

Method 201A (the reference method for dry catch of PM10) cannot be used due to high 

moisture content of the gas stream. Method 202 is for “back half” or the condensibles. In 

the past, “back half” was sometimes analyzed as per Minn. R. 7005.0500, and the result was 

termed “organic wet catch.” The waste gas stack at Line 3 is controlled with gravity 

collectors (see Table 2).

3. The waste gas stack at Line 3 is controlled with gravity collectors (see Table 2).
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Table 9. Line 1 Reference Method 29 testing at HTC (6/28/1994) 1

Stack A Stack D

Common data Run 1 Run 2 Run 1 Run 2

Sample volume, dscf 105.64 139.42 65.08 66.64

Stack gas flow, dscfm 157900 170800 149500 155400

Line rate, ton pellets/hr 390 344 390 344

Antimony, Sb Line emission factor (EF): < 1.06E-06

Mass recovered, ug < 0.40 < 0.40 < 0.40 < 0.40

Stack emission, lb/hr < 7.89E-05 < 6.47E-05 < 1.21E-04 < 1.23E-04

EF, lb/ton pellets fired < 2.02E-07 < 1.88E-07 < 3.11E-07 < 3.58E-07

Arsenic, As Line emission factor (EF): < 1.91E-04

Mass recovered, ug < 58.2 < 269 < 16.3 < 24.0

Stack emission, lb/hr < 1.15E-02 < 4.36E-02 < 4.95E-03 < 7.40E-03

EF, lb/ton pellets fired < 2.95E-05 < 1.27E-04 < 1.27E-05 < 2.15E-05

Cadmium, Cd Line emission factor (EF): < 2.51E-06

Mass recovered, ug < 0.799 1.69 1.46 0.18

Stack emission, lb/hr < 1.58E-04 2.74E-04 4.45E-04 5.65E-05

EF, lb/ton pellets fired < 4.05E-07 7.98E-07 1.14E-06 1.64E-07

Chromium, Cr Line emission factor (EF): < 8.14E-06

Mass recovered, ug < 1.90 < 4.20 < 2.92 < 3.25

Stack emission, lb/hr < 3.76E-04 < 6.81E-04 < 8.87E-04 < 1.00E-03

EF, lb/ton pellets fired < 9.64E-07 < 1.98E-06 < 2.28E-06 < 2.92E-06

Cobalt, Co Line emission factor (EF): < 1.17E-05

Mass recovered, ug < 4.39 < 4.39 < 4.39 < 4.39

Stack emission, lb/hr < 8.68E-04 < 7.11E-04 < 1.33E-03 < 1.35E-03

EF, lb/ton pellets fired < 2.23E-06 < 2.07E-06 < 3.42E-06 < 3.94E-06

Manganese, Mn Line emission factor (EF): 2.07E-04

Mass recovered, ug 12.30 245.90 72.20 32.00

Stack emission, lb/hr 2.43E-03 3.98E-02 2.19E-02 9.87E-03

EF, lb/ton pellets fired 6.24E-06 1.16E-04 5.63E-05 2.87E-05

Mercury, Hg Line emission factor (EF): < 2.27E-05

Mass recovered, ug < 6.21 < 4.28 < 9.69 < 11.14

Stack emission, lb/hr < 1.23E-03 < 6.94E-04 < 2.94E-03 < 3.44E-03

EF, lb/ton pellets fired < 3.15E-06 < 2.02E-06 < 7.55E-06 < 9.99E-06

Nickel, Ni Line emission factor (EF): 1.46E-05

Mass recovered, ug 10.07 7.14 3.65 3.71

Stack emission, lb/hr 1.99E-03 1.16E-03 1.11E-03 1.14E-03

EF, lb/ton pellets fired 5.11E-06 3.37E-06 2.85E-06 3.33E-06

Selenium, Se Line emission factor (EF): < 1.07E-05

Mass recovered, ug < 3.98 < 9.29 < 2.44 < 2.68

Stack emission, lb/hr < 7.87E-04 < 1.51E-03 < 7.41E-04 < 8.27E-04

EF, lb/ton pellets fired < 2.02E-06 < 4.38E-06 < 1.90E-06 < 2.40E-06

1. There are four stacks for Line 1, Stacks A through D. Only Stacks A & D 

were tested with two runs at each stack. Line emissions are assumed to be 

equal to twice the amount from Stacks A & D combined. The algebraic 

symbol “<” for mass recovered means that it was under the detection limit.
MPCA Report

Page 41

Table 10. Element composition analysis from Hibbing Taconite Company (ppm by weight) 1

Material Antimony Arsenic Beryllium Cadmium Chromium Cobalt Copper 2 Lead Manganese Nickel Selenium

Sb As Be Cd Cr Co Cu Pb Mn Ni Se

Taconite 0.84 13.21 1.2 0.03 49.7 6.1 21.9 1.3 3119 4.3 < 0.3

Std pellets 0.42 9.26 1.0 < 0.02 4.4 2.5 3.0 1.1 700 4.1 < 0.3

Limestone 0.19 1.32 0.4 0.11 1.8 0.9 2.9 3.6 494 3.3 < 0.3

Bentonite 1.09 5.84 2.2 0.25 9.9 5.6 7.7 34.9 597 8.9 < 0.3

Tails 1 1.05 12.36 1.1 0.04 55.8 3.0 15.2 1.7 4767 3.0 < 0.3

Tails 2 0.90 11.58 1.1 < 0.02 55.8 5.8 13.2 1.0 4822 4.5 < 0.3

Conc 1 0.21 9.36 0.6 < 0.02 32.3 2.6 2.4 0.8 801 < 2.1 < 0.3

Conc 2 < 0.06 10.46 0.7 < 0.02 24.3 2.7 1.6 0.6 719 2.6 < 0.3

Conc < 0.06 8.83 0.9 < 0.02 29.3 2.6 1.9 0.6 669 < 2.1 < 0.3

Tails < 0.06 15.75 1.2 < 0.02 55.1 6.6 9.8 0.6 4391 3.6 < 0.3

Greenballs 0.52 11.98 0.7 < 0.02 26.0 1.7 1.7 1.1 685 < 2.1 < 0.3

Std pellets 0.19 8.67 0.9 < 0.02 26.3 2.1 5.9 0.6 632 < 2.1 < 0.3

1. Test date: March 1997. The algebraic symbol, “<” (less than), indicates that the mass used in the analysis was below the detection limit.

2. Copper is not listed as hazardous air pollutant. However, it is of concern to the Great Lakes program.
MPCA Report

Page 42

Table 11. Performance testing of products of incomplete combustion and hydrogen chloride and hydrogen fluoride at HTC (July 1996) 1

Pollutant Parameter Stack E Stack H Line 2

Common to 3 PICs below: Run 1 Run 2 Run 3 Run 1 Run 2 Run 3 Run 1 Run 2 Run 3 Unit

Sample volume, dscf 2.211 2.053 1.9854 2.1824 2.1978 2.2304 89.7 98.1 95.3 MMBtu/hr, input

Stack gas flow, dscfm 153,859 150,923 155,375 162,633 156,364 165,694

Benzene Mass recovered, ug < 5 < 5 < 5 < 5 < 5 < 5 < 0.00206 lb/MMBtu for Line 2

Stack emission, lb/hour < 0.046 < 0.049 < 0.052 < 0.049 < 0.047 < 0.049 < 0.191 < 0.191 < 0.202 lb/hour for Line 2

Toluene Mass recovered, ug 7.2 5.3 5.8 < 5 < 5 < 5 < 0.00229 lb/MMBtu for Line 2

Stack emission, lb/hour 0.066 0.052 0.060 < 0.049 < 0.047 < 0.049 < 0.231 < 0.197 < 0.218 lb/hour for Line 2

Hexane Mass recovered, ug < 5 < 5 < 5 < 5 < 5 < 5 < 0.00206 lb/MMBtu for Line 2

Stack emission, lb/hour < 0.046 < 0.049 < 0.052 < 0.049 < 0.047 < 0.049 < 0.191 < 0.191 < 0.202 lb/hour for Line 2

HCHO Sample volume, dscf 55.17 57.04 57.14 55.23 54.40 54.26

Stack gas flow, dscfm 151,887 156,181 156,152 165,692 162,516 162,033

Mass recovered, ug 68 72 65 62 65 62 0.00105 lb/MMBtu for Line 2

Stack emission, lb/hour 0.025 0.026 0.023 0.025 0.026 0.024 0.099 0.104 0.096 lb/hour for Line 2

Common to HCl & HF: Run 1 Run 2 Run 3 Run 1 Run 2 Run 3 Run 1 Run 2 Run 3

Sample volume, dscf 48.22 47.88 47.45 48.65 48.56 48.17 391 439 438 ton pellets/hour

Stack gas flow, dscfm 156,575 157,072 156,598 164,647 158,589 159,679

HCl Mass recovered, ug 1337 1234 1337 535 617 679 0.00395 lb/ton pellets fired for Line 2

Stack emission, lb/hour 0.574 0.536 0.584 0.239 0.267 0.298 1.63 1.60 1.76 lb/hour for Line 2

HF Mass recovered, ug < 60.0 < 54.8 < 60.0 57.9 147 200 < 0.00039 lb/ton pellets fired for Line 2

Stack emission, lb/hour < 0.026 < 0.024 < 0.026 0.026 0.064 0.088 < 0.103 < 0.175 < 0.228 lb/hour for Line 2

1. There are four stacks for Line 2, Stacks E through H. Only Stacks E & H were tested. Line emissions are assumed to be equal to twice the amount from Stacks E & H 

combined. The algebraic symbol “<” for mass recovered means that it was under the detection limit. Test date: July 16-17, 1996.
MPCA Report

Page 43

Table 12. HAPs emission estimates for HTC’s taconite pelletizers 1

Pollutant Emission, 

ton/year

Emission 

factor

E.F. unit Emission factor source

Products of incomplete combustion based on annual heat input of 2,547,672 MMBtu/yr

Benzene < 2.63 < 0.00206 lb/MMBtu HTC 7/96

Toluene < 2.92 < 0.00229 lb/MMBtu HTC 7/96

Hexane < 2.63 < 0.00206 lb/MMBtu HTC 7/96

Formaldehyde 1.34 0.00105 lb/MMBtu HTC 7/96

Emissions which are related to production level--9,187,733 ton pellets/year

Hydrogen chloride 18.1 0.00395 lb/ton pel. HTC 7/96

Hydrogen fluoride < 1.81 < 0.00039 lb/ton pel. HTC 7/96

Metals at-pellet firing 2 Emission 

factor

E.F. unit Emission factor source

Antimony, Sb < 0.005 < 0.530 ppb of pel. HTC 6/94

Arsenic, As < 0.875 < 95.3 ppb of pel. HTC 6/94

Beryllium, Be < 0.012 < 1.26 ppb of pel. NMC 94

Cadmium, Cd < 0.012 < 1.25 ppb of pel. HTC 6/94

Chromium, Cr < 0.037 < 4.07 ppb of pel. HTC 6/94

Cobalt, Co < 0.054 < 5.83 ppb of pel. HTC 6/94

Lead, Pb 0.864 94.0 ppb of pel. HTC 5-10/94

Manganese, Mn 0.952 104 ppb of pel. HTC 6/94

Mercury, Hg 0.114 12.4 ppb of pel. HTC 9-10/98

Nickel, Ni 0.067 7.32 ppb of pel. HTC 6/94

Selenium, Se < 0.049 < 5.35 ppb of pel. HTC 6/94

1. The algebraic symbol, “<” (less than), indicates that the emission factor was developed from a stack 

test for which the mass recovered was below the detection limit for that air pollutant.

2. Reference Method 29 is the stack testing method for the elements listed here. See Table 9 for 

HTC’s emission factors. As an example, for antimony, the emission factor is 0.53 parts of the 

element in weight per 1 billion parts of pellets fired. Lead (Pb) emissions were determined in 

several stack tests conducted at HTC from May through October 1994. Beryllium emission factor 

was obtained from Northshore Mining Company’s 1994 stack testing results.
MPCA Report

Page 44

Table 13. HAPs emission estimation for off-pellet firing processes at Hibbing Taconite Company

Process group1 Ore Bentonite Greenballs Fired pellets Fluxstone Ore Bentonite Greenballs Fired pellets Fluxstone Year total

Year PM from Emission Inventory,2ton/year Sum of element emissions for process groups, ton/year 

1995 12.2 2.72 78.6 55.1 0.039 0.002 0.057 0.038 0.136

1996 11.5 3.76 52.9 51.8 0.037 0.003 0.039 0.036 0.114

1997 13.5 4.13 95.0 49.0 0.19 0.043 0.003 0.069 0.034 0.000096 0.149

Element Composition of elements,3

ppm by weight Individual element emissions, ton/year ‘95; sum:

4

Antimony, Sb 0.84 1.09 0.52 0.305 0.19 1.02E-05 2.96E-06 4.09E-05 1.68E-05 7.08E-05

Arsenic, As 13.2 5.84 11.98 8.97 1.32 1.61E-04 1.59E-05 9.41E-04 4.94E-04 1.61E-03

Beryllium, Be 1.20 2.2 0.7 0.95 0.4 1.46E-05 5.98E-06 5.50E-05 5.23E-05 1.28E-04

Cadmium, Cd 0.03 0.25 < 0.02 < 0.02 0.11 3.65E-07 6.80E-07 1.57E-06 1.10E-06 3.72E-06

Chromium, Cr 49.7 9.9 26.0 15.4 1.8 6.04E-04 2.69E-05 2.04E-03 8.46E-04 3.52E-03

Cobalt, Co 6.1 5.6 1.7 2.3 0.9 7.41E-05 1.52E-05 1.34E-04 1.27E-04 3.50E-04

Lead, Pb 1.3 34.9 1.1 0.85 3.6 1.58E-05 9.49E-05 8.64E-05 4.68E-05 2.44E-04

Manganese, Mn 3119 597 685 666 494 3.79E-02 1.62E-03 5.38E-02 3.67E-02 1.30E-01

Mercury, Hg 0.11 0.0121 0.13 0.002 0.007 1.34E-06 3.29E-08 1.02E-05 1.10E-07 1.17E-05

Nickel, Ni 4.3 8.9 < 2.1 3.1 3.3 5.22E-05 2.42E-05 1.65E-04 1.71E-04 4.12E-04

Selenium, Se < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 3.65E-06 8.16E-07 2.36E-05 1.65E-05 4.46E-05

Data source for Hg Ispat-Inland NMC Ispat-Inland NMC NMC

1. Process group is used here to simplify data presentation. The ore group includes coarse and fine crushing. The fired pellets group includes pellet stockpiling & loadout.

2. PM emissions, reported to the Emission Inventory, are not verified by MPCA staff.

3. Except for mercury, composition data in this block are provided by HTC (Table 10). For mercury data source, NMC means Northshore Mining Company.

4. Sum of element emissions in 1995 for off-pellet firing processes is also shown in Table 4. Those for 1995 & 1997 are omitted here to save space. All calculations were made 

using spreadsheets.
MPCA Report

Page 45

Table 14. PM10 stack testing of HTC’s pelletizers (Methods15 & 202)

Line 1 (gas fired) 2 Run 1 Run 2 Run 3 Average

Stack A Mass recovered, ug 14400 25100 24900 21467

Sample gas volume, dscf 44.18 43.08 43.22 43.49

Stack gas flow, dscfm 125,200 118,800 117,600 120,533

Isokinetic variation, % 101.7 103.5 104.1 103.1

Stack emission, lb/hr 5.40 9.16 8.96 7.84

Concentration, gr/dscf 0.00503 0.00899 0.00889 0.00764

Line, long ton pellets/hr 283 383 382 349

Stack ems/Line, lb/ton 0.01703 0.02134 0.02095 0.01977

Stack B Mass recovered, ug 25470 36426 16227 26041

Sample gas volume, dscf 47.05 40.16 48.61 45.27

Stack gas flow, dscfm 137200 116900 132700 128933

Isokinetic variation, % 103.4 101.1 107.1 103.9

Stack emission, lb/hr 9.82 14.0 5.86 9.90

Concentration, gr/dscf 0.00835 0.01400 0.00515 0.00917

Line, long ton pellets/hr 371 378 372 374

Stack ems/Line, lb/ton 0.02364 0.03313 0.01406 0.02361

Stack C Mass recovered, ug 21840 16804 12836 17160

Sample gas volume, dscf 45.81 46.55 52.05 48.14

Stack gas flow, dscfm 126300 126200 139000 130500

Isokinetic variation, % 106.2 106.0 105.9 106.0

Stack emission, lb/hr 7.96 6.03 4.53 6.18

Concentration, gr/dscf 0.00736 0.00557 0.00381 0.00558

Line, long ton pellets/hr 379 367 375 374

Stack ems/Line, lb/ton 0.01876 0.01466 0.01080 0.01474

Stack D Mass recovered, ug 18935 10886 25188 18336

Sample gas volume, dscf 49.47 45.60 48.62 47.89

Stack gas flow, dscfm 129400 124500 137000 130300

Isokinetic variation, % 106.5 102.8 103.4 104.2

Stack emission, lb/hr 6.55 3.93 9.39 6.62

Concentration, gr/dscf 0.00591 0.00368 0.00800 0.00586

Line, long ton pellets/hr 377 382 381 380

Stack ems/Line, lb/ton 0.01552 0.00919 0.02200 0.01557

Line Sum Line emission, lb/hr 29.7 33.1 28.7 30.5

Line EF, lb/ton pellets 0.07495 0.07833 0.06781 0.07370

1. Method 5, used for “front half” or “dry catch” of PM, is used to get a conservative 

estimate for PM10 emissions. Method 202 is for “back half” or “condensibles.”

2. Test dates: May 10 through 12, 1994.
MPCA Report

Page 46

Table 14. PM10 stack testing of HTC’s pelletizers (Methods15 & 202) (Continued)

Line 2 (gas fired) 2 Run 1 Run 2 Run 3 Average

Stack E Mass recovered, ug 42800 75200 38200 52067

Sample gas volume, dscf 45.94 49.01 47.60 47.52

Stack gas flow, dscfm 148705 151988 149838 150177

Isokinetic variation, % 98.0 102.3 100.8 100.4

Stack emission, lb/hr 18.33 30.85 15.91 21.69

Concentration, gr/dscf 0.01438 0.02368 0.01238 0.01681

Line, long ton pellets/hr 371 372 373 372

Stack ems/Line, lb/ton 0.04410 0.07404 0.03807 0.05207

Stack F Mass recovered, ug 38300 28000 25300 30533

Sample gas volume, dscf 48.20 48.31 49.40 48.64

Stack gas flow, dscfm 154454 155359 154403 154739

Isokinetic variation, % 99.0 98.7 101.5 99.7

Stack emission, lb/hr 16.23 11.91 10.46 12.87

Concentration, gr/dscf 0.01226 0.00894 0.00790 0.00970

Line, long ton pellets/hr 338 371 368 359

Stack ems/Line, lb/ton 0.04288 0.02866 0.02538 0.03231

Stack G Mass recovered, ug 23000 18500 22100 21200

Sample gas volume, dscf 54.03 54.86 54.86 54.58

Stack gas flow, dscfm 172111 174093 173255 173153

Isokinetic variation, % 99.6 100.0 100.4 100.0

Stack emission, lb/hr 9.69 7.77 9.23 8.90

Concentration, gr/dscf 0.00657 0.00520 0.00622 0.00600

Line, long ton pellets/hr 370 368 367 368

Stack ems/Line, lb/ton 0.02339 0.01884 0.02246 0.02156

Stack H Mass recovered, ug 15400 23500 19100 19333

Sample gas volume, dscf 53.02 52.97 52.58 52.86

Stack gas flow, dscfm 169233 166183 165589 167002

Isokinetic variation, % 99.4 100.9 100.5 100.3

Stack emission, lb/hr 6.50 9.75 7.96 8.07

Concentration, gr/dscf 0.00448 0.00685 0.00561 0.00564

Line, long ton pellets/hr 322 328 367 339

Stack ems/Line, lb/ton 0.01803 0.02655 0.01936 0.02131

Line Sum Line emission, lb/hr 50.8 60.3 43.6 51.5

Line EF, lb/ton pellets 0.12840 0.14809 0.10527 0.12726

1. Method 5, used for “front half” or “dry catch” of PM, is used to get a conservative 

estimate for PM10 emissions. Method 202 is for “back half” or “condensibles.”

2. Test dates: July 11 through 14, 1999.
MPCA Report

Page 47

Table 14. PM10 stack testing of HTC’s pelletizers (Methods15 & 202) (Continued)

Line 2 (gas fired) 2 Run 1 Run 2 Run 3 Average

Stack E Mass recovered, ug 8700 7400 15000 10367

Sample gas volume, dscf 49.32 46.55 43.54 46.47

Stack gas flow, dscfm 144600 126200 136700 135833

Isokinetic variation, % 95.6 95.4 95.8 95.6

Stack emission, lb/hr 3.37 2.65 6.23 4.09

Concentration, gr/dscf 0.00272 0.00245 0.00532 0.00350

Line, long ton pellets/hr 359 359 360 359

Stack ems/Line, lb/ton 0.00839 0.00660 0.01545 0.01015

Stack F Mass recovered, ug 14287 15624 21159 17023

Sample gas volume, dscf 48.55 45.46 50.77 48.26

Stack gas flow, dscfm 146700 137000 149200 144300

Isokinetic variation, % 98.7 97.4 97.7 97.9

Stack emission, lb/hr 5.71 6.23 8.22 6.72

Concentration, gr/dscf 0.00454 0.00530 0.00643 0.00543

Line, long ton pellets/hr 375 351 349 358

Stack ems/Line, lb/ton 0.01360 0.01584 0.02104 0.01683

Stack G Mass recovered, ug 26804 38601 17540 27648

Sample gas volume, dscf 45.99 48.79 50.27 48.35

Stack gas flow, dscfm 140700 148200 152300 147067

Isokinetic variation, % 99.3 98.5 98.7 98.8

Stack emission, lb/hr 10.8 15.5 7.03 11.1

Concentration, gr/dscf 0.00899 0.01221 0.00538 0.00886

Line, long ton pellets/hr 361 364 367 364

Stack ems/Line, lb/ton 0.02683 0.03805 0.01710 0.02733

Stack H Mass recovered, ug 30781 34101 40152 35011

Sample gas volume, dscf 46.61 53.58 45.09 48.42

Stack gas flow, dscfm 140600 158600 131700 143633

Isokinetic variation, % 99.2 100.6 101.0 100.3

Stack emission, lb/hr 12.3 13.4 15.5 13.7

Concentration, gr/dscf 0.01019 0.00982 0.01374 0.01125

Line, long ton pellets/hr 278 374 367 340

Stack ems/Line, lb/ton 0.01360 0.01584 0.02104 0.01683

Line Sum Line emission, lb/hr 32.2 37.7 37.0 35.7

Line EF, lb/ton pellets 0.06241 0.07633 0.07464 0.07113

1. Method 5, used for “front half” or “dry catch” of PM, is used to get a conservative 

estimate for PM10 emissions. Method 202 is for “back half” or “condensibles.”

2. Test dates: May 10 through 12, 1994.
MPCA Report

Page 48

Table 14. PM10 stack testing of HTC’s pelletizers (Methods15 & 202) (Continued)

Line 2 (oil fired) 2 Run 1 Run 2 Run 3 Average

Stack E Mass recovered, ug 17800 24600 12000 18133

Sample gas volume, dscf 48.87 49.35 47.93 48.72

Stack gas flow, dscfm 139500 141400 136300 139067

Isokinetic variation, % 103.8 103.4 104.1 103.8

Stack emission, lb/hr 6.72 9.32 4.51 6.85

Concentration, gr/dscf 0.00562 0.00769 0.00386 0.00573

Line, long ton pellets/hr 329 324 329 327

Stack ems/Line, lb/ton 0.01824 0.02569 0.01225 0.01873

Stack F Mass recovered, ug 28408 35238 18310 27319

Sample gas volume, dscf 51.68 54.02 52.39 52.70

Stack gas flow, dscfm 151200 156800 153700 153900

Isokinetic variation, % 100.5 101.3 100.2 100.7

Stack emission, lb/hr 11.0 13.5 7.11 10.5

Concentration, gr/dscf 0.00848 0.01007 0.00539 0.00798

Line, long ton pellets/hr 329 324 329 327

Stack ems/Line, lb/ton 0.02984 0.03728 0.01928 0.02880

Stack G Mass recovered, ug 49365 28611 19717 32564

Sample gas volume, dscf 50.96 51.95 53.46 52.12

Stack gas flow, dscfm 159700 160000 164700 161467

Isokinetic variation, % 94.6 96.2 96.2 95.7

Stack emission, lb/hr 20.5 11.7 8.03 13.4

Concentration, gr/dscf 0.01495 0.00850 0.00569 0.00971

Line, long ton pellets/hr 329 341 337 335.6667

Stack ems/Line, lb/ton 0.05554 0.03052 0.02129 0.03578

Stack H Mass recovered, ug 42496 36010 27614 35373

Sample gas volume, dscf 53.22 55.01 56.45 54.89

Stack gas flow, dscfm 163800 170600 174200 169533

Isokinetic variation, % 95.5 94.8 95.3 95.2

Stack emission, lb/hr 17.3 14.8 11.3 14.4

Concentration, gr/dscf 0.01232 0.01010 0.00755 0.00999

Line, long ton pellets/hr 329 341 337 336

Stack ems/Line, lb/ton 0.04696 0.03868 0.02986 0.03850

Line Sum Line emission, lb/hr 55.5 49.3 30.9 45.2

Line EF, lb/ton pellets 0.15057 0.13217 0.08269 0.12181

1. Method 5, used for “front half” or “dry catch” of PM, is used to get a conservative 

estimate for PM10 emissions. Method 202 is for “back half” or “condensibles.”

2. Test dates: June 29 through 30, 1994.
MPCA Report

Page 49

Table 14. PM10 stack testing of HTC’s pelletizers (Methods15 & 202) (Continued)

Line 3 ( gas fired) 2 Run 1 Run 2 Run 3 Average

Stack J Mass recovered, ug 44474 61161 43719 49785

Sample gas volume, dscf 51.30 52.25 51.81 51.79

Stack gas flow, dscfm 149200 153800 151700 151567

Isokinetic variation, % 101.1 100.5 100.4 100.7

Stack emission, lb/hr 17.1 23.8 16.9 19.3

Concentration, gr/dscf 0.01338 0.01807 0.01302 0.01482

Line, long ton pellets/hr 391 389 388 389

Stack ems/Line, lb/ton 0.03907 0.05466 0.03896 0.04423

Stack K Mass recovered, ug 49898 29802 28130 35943

Sample gas volume, dscf 65.63 64.63 60.60 63.62

Stack gas flow, dscfm 179000 175200 165400 173200

Isokinetic variation, % 107.8 108.4 107.7 108.0

Stack emission, lb/hr 18.0 10.7 10.2 12.9

Concentration, gr/dscf 0.01173 0.00712 0.00716 0.00867

Line, long ton pellets/hr 389 397 397 394

Stack ems/Line, lb/ton 0.04132 0.02403 0.02284 0.02940

Stack L Mass recovered, ug 58799 46895 44906 50200

Sample gas volume, dscf 54.05 54.78 52.31 53.71

Stack gas flow, dscfm 146900 150400 143700 147000

Isokinetic variation, % 108.2 107.1 107.0 107.4

Stack emission, lb/hr 21.1 17.0 16.3 18.2

Concentration, gr/dscf 0.01679 0.01321 0.01325 0.01442

Line, long ton pellets/hr 395 387 398 393

Stack ems/Line, lb/ton 0.04778 0.03929 0.03661 0.04123

Stack M Mass recovered, ug 52466 43260 33600 43108

Sample gas volume, dscf 63.86 62.00 62.88 62.91

Stack gas flow, dscfm 175000 171300 176000 174100

Isokinetic variation, % 107.3 106.4 105.1 106.3

Stack emission, lb/hr 19.0 15.8 12.4 15.8

Concentration, gr/dscf 0.01268 0.01077 0.00825 0.01056

Line, long ton pellets/hr 392 389 393 391

Stack ems/Line, lb/ton 0.04332 0.03629 0.02826 0.03596

Line Sum Line emission, lb/hr 75.3 67.3 55.8 66.2

Line EF, lb/ton pellets 0.17149 0.15428 0.12668 0.15082

1. Method 5, used for “front half” or “dry catch” of PM, is used to get a conservative 

estimate for PM10 emissions. Method 202 is for “back half” or “condensibles.”

2. Test dates: September 27 through October 12, 1994.
MPCA Report

Page 50

Table 15. Performance testing for PICs at LTV Steel Mining Company 1

Common to all compounds listed below: Run 1 Run 2 Run 3 Average

Stack gas flow rate, dscfm 38,443 39,397 38,116 38,652

Heat input rate, MMBtu/hr 25 25 25 25

Common to 3PICs listed below:

Sample gas volume, dscf 0.726 0.710 0.728

Benzene Mass recovered, ug < 2.1 < 2.1 < 2.1

Stack emission, lb/hr < 0.015 < 0.015 < 0.015

Line emission factor, lb/MMBtu < 0.00059 < 0.00062 < 0.00058 < 0.00060

Toluene Mass recovered, ug < 2.1 < 2.1 < 2.1

Stack emission, lb/hr < 0.015 < 0.015 < 0.015

Line emission factor, lb/MMBtu < 0.00059 < 0.00062 < 0.00058 < 0.00060

Hexane Mass recovered, ug < 2.6 < 2.6 < 2.6

Stack emission, lb/hr < 0.018 < 0.019 < 0.018

Line emission factor, lb/MMBtu < 0.00073 < 0.00076 < 0.00072 < 0.00074

HCHO Sample gas volume, dscf 49.65 52.02 51.05

Mass recovered, ug 290 100 110

Stack emission, lb/hr 0.030 0.010 0.011

Line emission factor, lb/MMBtu 0.00119 0.00040 0.00043 0.00067

1. There is only one top gas stack. Test date: November 21, 1995. The algebraic symbol “<” 

for mass recovered means that it was under the detection limit.
MPCA Report

Page 51

Table 16. HAPs emission estimates for LTVSMC’s taconite pelletizers 1

Pollutant Emission, 

ton/year

Emission 

factor

E.F. unit Emission factor source

Products of incomplete combustion based on annual heat input of 3,930,631 MMBtu/yr

Benzene < 1.17 < 0.00060 lb/MMBtu LTVSMC 11/95

Toluene < 1.17 < 0.00060 lb/MMBtu LTVSMC 11/95

Hexane < 1.45 < 0.00074 lb/MMBtu LTVSMC 11/95

Formaldehyde 1.33 0.00067 lb/MMBtu LTVSMC 11/95

Emissions which are related to production level—8,559,040 ton pellets/year & 0% fluxstone usage

Hydrogen chloride 56.7 From regression equation2and NSPC 8/99

Hydrogen fluoride 95.3 0.00562 lb/ton pel. NMC 1/92; NSPC 8/99

Metals at-pellet firing 3 Emission 

factor

E.F. unit Emission factor source

Antimony, Sb < 0.082 < 13.3 ppb pellets Ispat-Inland 94

Arsenic, As 1.72 208 ppb pellets EVTAC L2 97

Beryllium, Be < 0.009 < 1.26 ppb pellets NMC 94

Cadmium, Cd 0.016 2.68 ppb pellets Ispat-Inland 94

Chromium, Cr 0.537 67.0 ppb pellets NMC 5/98

Cobalt, Co < 0.018 < 1.40 ppb pellets EVTAC L1 97

Lead, Pb 0.923 147 ppb pellets Ispat-Inland 94

Manganese, Mn 1.61 107 ppb pellets Ispat-Inland 94

Mercury, Hg 0.043 5.02 ppb pellets LTV 4/1998 & 5/2000

Nickel, Ni 0.398 57.2 ppb pellets EVTAC L2 97

Selenium, Se 0.221 13.5 ppb pellets NMC 5/98

1. The algebraic symbol, “<” (less than), indicates that the emission factor was developed from a stack 

test for which the mass recovered was below the detection limit for that air pollutant.

2. See equation [1] in the Package 2 text, which is applied to 12 of the 24 furnaces that use concentrate 

slurry scrubbing at the waste gas stream. HCl emission factor from National Steel Pellet Company, 

0.03096 lb/ton pellets fired, is applied to the remaining furnaces.

3. Reference Method 29 is the stack testing method for the elements listed here. Two sets of emission 

factors are used. Listed here is the first set (for example, less than 13.3 parts of antimony in weight 

per 1 billion parts of pellets fired), which was applied to the 12 furnaces with slurry scrubbing. The 

second set, also in units of ppb of pellets fired, is taken from the August 1999 stack testing at 

National Steel Pellet Company (see Table 24). The second set of emission factors was applied to 

the 12 furnaces without slurry scrubbing. In 1997, approximately 66.89% of pellets were produced 

from the furnaces with the slurry scrubbing retrofit.
MPCA Report

Page 52

Table 17. HAPs emission estimation for off-pellet firing processes at LTVSMC 1

Process group2 Ore Bentonite Prod handl Ore Bentonite Prod handl Year total

Year PM emissions,3ton/year Sum of element emissions, ton/year

1995 347 15.2 9792 1.80 0.008 9.90 11.7

1996 162 11.6 2582 0.844 0.006 2.61 3.46

1997 340 13.9 10334 1.77 0.01 10.45 12.2

Element Composition, ppm by weight Individual element emission, ton/yr ’95 sum 4

Antimony, Sb 8.07 1.00 0.414 2.80E-03 1.52E-05 4.05E-03 6.86E-03

Arsenic, As 14.7 3.31 4.88 5.10E-03 5.02E-05 4.78E-02 5.30E-02

Beryllium, Be 2.12 2.25 0.742 7.34E-04 3.42E-05 7.27E-03 8.03E-03

Cadmium, Cd 1.05 0.233 0.028 3.64E-04 3.54E-06 2.74E-04 6.42E-04

Chromium, Cr 23.5 5.80 23.6 8.15E-03 8.79E-05 2.31E-01 2.39E-01

Cobalt, Co 10.0 3.23 7.06 3.45E-03 4.90E-05 6.91E-02 7.26E-02

Lead, Pb 13.1 34.4 0.580 4.55E-03 5.22E-04 5.68E-03 1.08E-02

Manganese, Mn 5107 479 968 1.77E+00 7.26E-03 9.48E+00 1.13E+01

Mercury, Hg 5.06 0.012 0.002 1.75E-03 1.83E-07 1.96E-05 1.77E-03

Nickel, Ni 7.04 5.83 5.64 2.44E-03 8.84E-05 5.52E-02 5.78E-02

Selenium, Se 10.8 0.267 0.280 3.74E-03 4.04E-06 2.74E-03 6.49E-03

Data source 5(a) (b) (c)

1. Since average composition data are used (see footnote 4 below), tracking of values of below detection limits is 

difficult. Thus, the algebraic symbol “<” is omitted in this table.

2. Process group is used here to simplify data presentation. The ore group includes coarse and fine crushing. 

The fired pellets group includes pellet stockpiling and loadout.

3. PM emissions, reported to the Emission Inventory, are not verified by MPCA staff.

4. Sum of element emissions in 1995 for off-pellet firing processes is also shown in Table 4. Those for 1996 and 

1997 are omitted here to save space. All calculations were made using spreadsheets.

5. Composition data listed in this table are the average values reported by non-LTVSMC facilities. (a) For the 

ore group, the composition data are provided by Northshore Mining, Hibbing Taconite, Ispat-Inland, EVTAC, 

and Minnesota Geological Survey. (b) For the bentonite group, the composition data are provided by 

Northshore Mining and Hibbing Taconite. (c) For the fired pellets group, the composition data are provided 

by Northshore Mining, Hibbing Taconite, Ispat-Inland, and EVTAC.
MPCA Report

Page 53

Table 18. PM10 testing results for LTVSMC’s pelletizers’ top gas stacks 1

E2 (Methods 201A & 202; 4/14/98)2 Run 1 Run 2 Run 3 Average

Mass recovered, ug 164,900 134,300 228,500 175,900

Sample gas volume, dscf 35.98 29.44 33.02 32.81

Stack gas flow, dscfm 49,099 46,945 50,134 48,726

Isokinetic variation, % 110.8 117 108.8 112.2

Stack emission, lb/hr 29.77 28.33 45.89 34.66

Concentration, gr/dscf 0.07073 0.07040 0.10679 0.08264

Pellets, long ton/hour 48 48 48 48

Line emission factor, lb/ton pellets fired 0.55368 0.52693 0.85185 0.64415

Notes: This was a voluntary, gas fired test. MPCA review letter is dated 6/9/98.

E2 (Method 5 & 202; 11/18-19/97) Run 1 Run 2 Run 3 Average

Mass recovered, ug 254,919 246,021 138,126 213,022

Sample gas volume, dscf 32.24 31.32 30.96 31.51

Stack gas flow, dscfm 57,296 54,388 55,806 55,830

Isokinetic variation, % 93.8 99.4 95.7 96.3

Stack emission, lb/hr 59.93 56.51 32.93 49.79

Concentration, gr/dscf 0.12202 0.12122 0.06885 0.10403

Pellets, long ton/hour 45.34 45.08 45.19 45.20

Line emission factor, lb/ton pellets fired 1.1801 1.1193 0.65070 0.98336

Notes: This was a voluntary, gas fired test. MPCA review letter is dated 2/20/98.

E2 (Method 5 & 202; 11/18/97) Run 1 Run 2 Run 3 Average

Mass recovered, ug 124,605 150,584 136,506 137,232

Sample gas volume, dscf 33.69 33.61 33.55 33.62

Stack gas flow, dscfm 51,599 52,410 56,772 53,594

Isokinetic variation, % 99.6 103.2 94.1 99.0

Stack emission, lb/hr 25.24 31.06 30.55 28.95

Concentration, gr/dscf 0.05708 0.06914 0.06279 0.06300

Pellets, long ton/hour 45.49 45.47 45.53 45.50

Line emission factor, lb/ton pellets fired 0.49548 0.60991 0.59919 0.56819

Notes: This was a voluntary, fuel oil fired test. MPCA review letter is dated 2/20/98.

1. All furnaces are equipped with a multiclone for top gas cleaning. Top gas cleaning is also 

enhanced for Furnace F3 (with a heat exchanger) but not for Furnace E2.

2. Method 5 is for “front half” or “dry catch” for PM. It is often used to get a conservative 

estimate for PM10 emissions. Method 202 is for “back half” or “condensibles.”
MPCA Report

Page 54

Table 18. PM10 testing results for LTVSMC’s pelletizers’ top gas stacks 1(Continued)

F3 (Methods 5 & 202; 11/20/97)2 Run 1 Run 2 Run 3 Average

Mass recovered, ug 236,456 261,817 202,258 233,510

Sample gas volume, dscf 41.03 42.46 40.64 41.38

Stack gas flow, dscfm 37,513 38,691 36,713 37,639

Isokinetic variation, % 99.2 99.5 100.4 99.7

Stack emission, lb/hr 28.60 31.56 24.17 28.11

Concentration, gr/dscf 0.08894 0.09516 0.07680 0.08697

Pellets, long ton/hour 47.87 48.18 47.65 47.90

Line emission factor, lb/ton pellets fired 0.53338 0.58483 0.45287 0.52369

Notes: This was a voluntary, gas fired test. MPCA review letter is dated 2/20/98.

F3 (Methods 5 & 202; 11/20/97) Run 1 Run 2 Run 3 Average

Mass recovered, ug 103,550 119,990 207,672 143,737

Sample gas volume, dscf 41.62 40.61 39.23 40.49

Stack gas flow, dscfm 38,340 37,221 35,542 37,034

Isokinetic variation, % 98.4 98.9 100.1 99.1

Stack emission, lb/hr 12.62 14.55 24.89 17.35

Concentration, gr/dscf 0.03840 0.04560 0.08169 0.05523

Pellets, long ton/hour 47.89 47.98 48.04 47.97

Line emission factor, lb/ton pellets fired 0.23525 0.27071 0.46256 0.32284

Notes: This was a voluntary, fuel oil fired test. MPCA review letter is dated 2/20/98.

F3 (Methods 5 & 202; 7/14/95) Run 1 Run 2 Run 3 Average

Mass recovered, ug 74,424 54,807 74,446 67,892

Sample gas volume, dscf 41.41 43.40 42.40 42.40

Stack gas flow, dscfm 38,074 40,362 39,047 39,161

Isokinetic variation, % 99.3 98.2 99.1 98.9

Stack emission, lb/hr 9.05 6.74 9.07 8.29

Concentration, gr/dscf 0.02774 0.01949 0.02710 0.02477

Pellets, long ton/hour 52.03 51.76 52.03 51.94

Line emission factor, lb/ton pellets fired 0.15533 0.11630 0.15562 0.14242

Notes: This was an engineering, gas fired test. MPCA review letter is dated 12/5/95.

1. All furnaces are equipped with a multiclone for top gas cleaning. Top gas cleaning is also 

enhanced for Furnace F3 (with a heat exchanger) but not for Furnace E2.

2. Method 5 is for “front half” or “dry catch” for PM. It is often used to get a conservative 

estimate for PM10 emissions. Method 202 is for “back half” or “condensibles.”
MPCA Report

Page 55

Table 19. Reference Method 29 testing at EVTAC’s Pelletizers (Nov. 18-20, 1997)

Line 1 Stack 2A of Line 2

Common data Run 1 Run 2 Run 3 Run 1 Run 2 Run 3

Sample volume, dscf 83.22 86.37 86.91 97.06 95.41 101.03

Stack gas flow, dscfm 281,548 283,684 283,540 285,199 282,314 292,425

Line rate, ton pellets/hour 225 241 241 522 554 468

Antimony, Sb Line 1 emission factor: < 2.79E-06 Line 2 emission factor:1

 < 2.09E-06

Mass recovered, ug < 1.5 < 1.5 < 1.5 < 1.5 < 1.5 < 1.5

Stack emission, lb/hour < 6.71E-04 < 6.52E-04 < 6.47E-04 < 5.58E-04 < 5.67E-04 < 5.63E-04

EF, lb/ton pellets fired < 2.98E-06 < 2.71E-06 < 2.69E-06 < 1.07E-06 < 1.02E-06 < 1.09E-06

Arsenic, As Line 1 emission factor: 1.08E-04 Line 2 emission factor: 3.88E-04

Mass recovered, ug 60.5 58.2 54.8 367.1 151.4 312.0

Stack emission, lb/hour 2.71E-02 2.53E-02 2.36E-02 1.37E-01 5.73E-02 1.17E-01

EF, lb/ton pellets fired 1.20E-04 1.05E-04 9.82E-05 2.62E-04 1.03E-04 2.26E-04

Beryllium, Be Line 1 emission factor: 3.26E-07 Line 2 emission factor: 5.01E-07

Mass recovered, ug 0.161 0.176 0.190 0.436 0.179 0.456

Stack emission, lb/hour 7.21E-05 7.65E-05 8.20E-05 1.62E-04 6.77E-05 1.71E-04

EF, lb/ton pellets fired 3.20E-07 3.18E-07 3.41E-07 3.11E-07 1.22E-07 3.31E-07

Cadmium, Cd Line 1 emission factor: 2.76E-06 Line 2 emission factor: 2.40E-06

Mass recovered, ug 2.794 1.238 0.268 2.518 1.658 1.010

Stack emission, lb/hour 1.25E-03 5.38E-04 1.16E-04 9.36E-04 6.27E-04 3. 78E-04

EF, lb/ton pellets fired 5.55E-06 2.23E-06 4.80E-07 1.79E-06 1.13E-06 7.33E-07

Chromium, Cr Line 1 emission factor: 7.93E-06 Line 2 emission factor: 3.48E-05

Mass recovered, ug 4.549 4.199 4.009 53.139 9.119 12.339

Stack emission, lb/hour 2.04E-03 1.82E-03 1.73E-03 1.98E-02 3.45E-03 4.62E-03

EF, lb/ton pellets fired 9.04E-06 7.58E-06 7.18E-06 3.79E-05 6.22E-06 8.95E-06

Cobalt, Co Line 1 emission factor: < 2.79E-06 Line 2 emission factor: < 1.51E-06

Mass recovered, ug < 1.5 < 1.5 < 1.5 0.916 < 1.500 0.856

Stack emission, lb/hour < 6.71E-04 < 6.52E-04 < 6.47E-04 3.41E-04 < 5.67E-04 3.21E-04

EF, lb/ton pellets fired < 2.98E-06 < 2.71E-06 < 2.69E-06 6.53E-07 < 1.02E-06 6.21E-07

Lead, Pb Line 1 emission factor: 2.46E-05 Line 2 emission factor: 2.70E-05

Mass recovered, ug 17.26 12.72 9.27 23.46 10.94 23.40

Stack emission, lb/hour 7.72E-03 5.53E-03 4.00E-03 8.72E-03 4.14E-03 8.77E-03

EF, lb/ton pellets fired 3.43E-05 2.30E-05 1.66E-05 1.67E-05 7.47E-06 1.70E-05

Manganese, Mn Line 1 emission factor: 6.92E-05 Line 2 emission factor: 7.16E-05

Mass recovered, ug 40.99 38.05 32.05 71.38 37.18 45.49

Stack emission, lb/hour 1.83E-02 1.65E-02 1.38E-02 2.65E-02 1.41E-02 1.70E-02

EF, lb/ton pellets fired 8.15E-05 6.87E-05 5.74E-05 5.09E-05 2.54E-05 3.30E-05

Mercury, Hg Line 1 emission factor: 2.55E-05 Line 2 emission factor: 2.12E-05

Mass recovered, ug 14.3 13.9 12.8 15.10 15.64 15.00

Stack emission, lb/hour 6.40E-03 6.04E-03 5.52E-03 5.62E-03 5.92E-03 5.62E-03

EF, lb/ton pellets fired 2.84E-05 2.51E-05 2.29E-05 1.08E-05 1.07E-05 1.09E-05

Nickel, Ni Line 1 emission factor: 6.57E-06 Line 2 emission factor: 1.06E-04

Mass recovered, ug 3.093 3.023 4.523 99.853 40.903 87.223

Stack emission, lb/hour 1.38E-03 1.31E-03 1.95E-03 3.71E-02 1.55E-02 3.27E-02

EF, lb/ton pellets fired 6.15E-06 5.45E-06 8.11E-06 7.12E-05 2.79E-05 6.33E-05

1. A factor of 1.967 is used for Line 2 emission factor calculation with data for stack 2A. The factor was 

obtained by gas flow comparison between 2A (tabulated above) and 2B (272,885, 272,885, and 286,164).
MPCA Report

Page 56

Table 20. Composition data from EVTAC (ppm by weight) 1

Element Rod mill feed Concentrate Fired pellets

Antimony, Sb 12 22 17

Arsenic, As 15 6 9

Beryllium, Be 5 9 6

Cadmium, Cd < 0.5 < 0.5 < 0.5

Chromium, Cr 24 80 124

Cobalt, Co 48 89 61

Lead, Pb 20 38 27

Manganese, Mn 3900 850 940

Mercury, Hg < 10 < 10 < 10

Nickel, Ni 13 4 5

Selenium, Se < 5 < 5 < 5

1. Test date: June 1994. The algebraic symbol, “<” (less than), 

indicates that the mass used in the analysis was below the detection 

limit.
MPCA Report

Page 57

Table 21. HAPs emission estimates for EVTAC’s taconite pelletizers 1

Pollutant Emission, 

ton/year

Emission 

factor

E.F. unit Emission factor source

Products of incomplete combustion based on annual heat input of 2,834,396 MMBtu/yr

Benzene < 2.93 < 0.00206 lb/MMBtu HTC 7/96

Toluene < 3.25 < 0.00229 lb/MMBtu HTC 7/96

Hexane < 2.93 < 0.00206 lb/MMBtu HTC 7/96

Formaldehyde 30.8 0.02173 lb/MMBtu NMC 10/95

Emissions which are related to production level--5,685,120 ton pellets/year & 0.70% fluxstone usage

Hydrogen chloride 14.6 From linear regression model 2

Hydrogen fluoride 16.0 0.00562 lb/ton pel. NMC 1/92

Metals at-pellet firing 3 Line 1, ppb Line 2, ppb Data source

Antimony, Sb < 0.007 < 1.40 < 1.04 EVTAC 11/97

Arsenic, As 0.863 53.9 194 EVTAC 11/97

Beryllium, Be 0.001 0.163 0.250 EVTAC 11/97

Cadmium, Cd 0.007 1.38 1.20 EVTAC 11/97

Chromium, Cr 0.076 3.97 17.4 EVTAC 11/97

Cobalt, Co < 0.005 < 1.40 < 0.753 EVTAC 11/97

Lead, Pb 0.075 12.3 13.5 EVTAC 11/97

Manganese, Mn 0.202 34.6 35.8 EVTAC 11/97

Mercury, Hg 0.064 12.7 10.6 EVTAC 11/97

Nickel, Ni 0.217 3.28 53.2 EVTAC 11/97

Selenium, Se 0.077 13.5 13.5 NMC 5/98

1. The algebraic symbol, “<” (less than), indicates that the emission factor was developed from a stack test for 

which the mass recovered was below the detection limit for that air pollutant.

2. See equation [1] in the Package 2 text for detail of the linear regression model.

3. Reference Method 29 is the stack testing method for the elements listed here. Except for selenium, for which 

stack testing results from Northshore Mining Company were used, the emission factors for Lines 1 and 2 can be 

found in Table 19. As an example, for antimony, the emission factor is less than 1.40 parts of the element in 

weight per 1 billion parts of pellets fired (ppb of pellets) for Line 1 and less than 1.12 ppb of pellets for Line 2. 

To calculate metals emission estimates, the line-specific emission factors were weighted with line production 

data. Based on the production data from 1995 through 1997, Line 1 was assumed to produce 30% of the pellets

from the two-line, EVTAC facility. Also note that an EVTAC’s decision to idle Line 1 by May 31, 1999 did 

not affect the above HAPs emission estimates, which are based on average production and emission data from 

1995 to 1997.
MPCA Report

Page 58

Table 22. HAPs emission estimation for off-pellet firing processes at EVTAC

Process group1 Ore Greenballs Fired pellets Fluxstone Ore Greenballs Fired pellets Fluxstone Year total

Year PM from Emission Inventory,2ton/year Sum of element emissions for process groups, ton/year

1995 409 255 643 0.040 1.66 0.283 0.775 2.598E-06 2.72

1996 404 239 369 0.040 1.64 0.267 0.445 2.598E-06 2.35

1997 787 187 1582 0.090 3.19 0.208 1.91 5.846E-06 5.30

Element Composition of elements, ppm by weight Individual element emissions, ton/year ’95 sum3

Antimony, Sb 12 22 17 0.530 4.91E-03 5.60E-03 1.09E-02 2.12E-08 2.14E-02

Arsenic, As 15 6 9 1.69 6.14E-03 1.53E-03 5.79E-03 6.74E-08 1.35E-02

Beryllium, Be 5 9 6 1.380 2.05E-03 2.29E-03 3.86E-03 5.52E-08 8.20E-03

Cadmium, Cd < 0.5 < 0.5 < 0.5 0.305 2.05E-04 1.27E-04 3.22E-04 1.22E-08 6.54E-04

Chromium, Cr 24 80 124 6.15 9.83E-03 2.04E-02 7.98E-02 2.46E-07 1.10E-01

Cobalt, Co 48 89 61 7.85 1.97E-02 2.27E-02 3.92E-02 3.14E-07 8.16E-02

Lead, Pb 20 38 27 1.25 8.19E-03 9.67E-03 1.74E-02 5.00E-08 3.52E-02

Manganese, Mn 3900 850 940 35.5 1.60E+00 2.16E-01 6.05E-01 1.42E-06 2.42E+00

Mercury, Hg < 10 < 10 < 10 0.058 4.09E-03 2.55E-03 6.43E-03 2.32E-09 1.31E-02

Nickel, Ni 13 4 5 7.75 5.32E-03 1.02E-03 3.22E-03 3.10E-07 9.56E-03

Selenium, Se < 5 < 5 < 5 2.50 2.05E-03 1.27E-03 3.22E-03 1.00E-07 6.54E-03

Data source EVTAC 11/97 (Table 19) NMC

1. Process group is used here to simplify data presentation. The ore group includes coarse and fine crushing. The fired pellets group includes pellet 

stockpiling and loadout.

2. PM emissions, reported to the Emission Inventory, are not verified by MPCA staff.

3. Sum of element emissions in 1995 for off-pellet firing processes is also shown in Table 4. Those for 1996 and 1997 are omitted to save space. All 

calculations were made using spreadsheets.
MPCA Report

Page 59

Table 23. PM10 stack testing of EVTAC’s pelletizers (Methods 5 & 202) 1

Line 1 (Test date: 11/21/97) Run 1 Run 2 Run 3 Average

Mass recovered, ug 18,500 17,300 16,600 17,467

Sample gas volume, dscf 37.52 37.57 37.99 37.69

Stack gas flow, dscfm 283,687 282,378 283,006 283,024

Isokinetic variation, % 99.2 99.8 100.7 99.9

Stack emission, lb/hr 18.50 17.20 16.36 17.35

Concentration, gr/dscf 0.00761 0.00711 0.00674 0.00715

Line rate, long ton pellets /hour 213 213 226 217

Line emission factor, lb/ton pellets fired 0.07756 0.07210 0.06462 0.07143

Notes: This was an engineering, gas fired test; MPCA review letter is dated 6/5/98.

Stack 2A (Test date: 11/21/97) Run 1 Run 2 Run 3 Average

Mass recovered, ug 53,400 56,300 58,100 55,933

Sample gas volume, dscf 48.24 49 48.59 48.61

Stack gas flow, dscfm 296,681 295,241 291,402 294,441

Isokinetic variation, % 98.4 100.5 100.9 99.9

Stack emission, lb/hr 43.44 44.87 46.09 44.80

Concentration, gr/dscf 0.01708 0.01773 0.01845 0.01776

Line rate, long ton pellets /hour 489 489 489 489

Line emission factor, lb/ton pellets fired 0.15864 0.16386 0.16831 0.16360

Notes: This was an engineering, solid fuel (coal & petroleum coke blend) fired test; MPCA 

review letter is dated 6/5/98. It was assumed that Line 2 emissions = 2×Stack 2A emissions.

Line 2 (Test date: 12/3-4/96) Run 1 Run 2 Run 3 Average

Stack 2A: Mass recovered, ug 69,100 56,700 65,600 63,800

Sample gas volume, dscf 49.3 48.41 47.58 48.43

Stack gas flow, dscfm 305,001 309,551 305,961 306,838

Isokinetic variation, % 98.7 95.5 94.9 96.4

Stack emission, lb/hr 56.55 47.96 55.80 53.44

Concentration, gr/dscf 0.02163 0.01808 0.02128 0.02033

Line rate, long ton pellets /hr 526 526 526 526

Stack 2B: Mass recovered, ug 35,700 25,600 32,600 31,300

Sample gas volume, dscf 42.83 42.96 42.74 42.84

Stack gas flow, dscfm 270,438 270,920 271,351 270,903

Isokinetic variation, % 96.7 96.8 96.1 96.5

Stack emission, lb/hr 29.82 21.36 27.38 26.18

Concentration, gr/dscf 0.01286 0.00920 0.01177 0.01128

Line rate, long ton pellets /hr 519 519 519 519

Line emission factor, lb/ton pellets fired 0.14728 0.11815 0.14182 0.13575

Notes: This was a solid fuel (coal & petroleum coke blend) fired test, requested by MPCA (the 

review letter is dated 6/5/98). Line 2 emissions = Stack 2A emissions + Stack 2B emissions.

1. Method 5, used for “front half” or “dry catch” for PM, is used to get a conservative estimate 

for PM10 emissions. Method 202 is for “back half” or “condensibles.”
MPCA Report

Page 60

Table 24. HAPs Stack Testing1at National Steel Pellet Company in August 1999

Waste Gas Stack 2A Waste Gas Stack 2B

Method 29, 8/10/99 Run 1 Run 2 Run 3 Run 1 Run 2 Run 3

Sample volume, dscf 84.04 82.69 84.38 77.90 76.40 76.30

Stack gas flow, dscfm 254,200 248,523 254,354 255,934 250,497 250,430

Line rate, ton pellets/hr 749 749 749 749 749 749

Antimony, Sb Line emission factor (EF): 3.93E-06 lb/ton pellets

Mass recovered, ug 14.9 1.00 1.00 1.53 1.000 2.26

Stack emission, lb/hr 0.00596 0.00040 0.00040 0.00066 0.00043 0.0010

EF, lb/ton pellets fired 7.96E-06 5.31E-07 5.32E-07 8.87E-07 5.79E-07 1.31E-06

Arsenic, As Line emission factor (EF): 3.72E-04 lb/ton pellets

Mass recovered, ug 311 374 341 325 341 318

Stack emission, lb/hr 0.124 0.148 0.136 0.141 0.148 0.138

EF, lb/ton pellets fired 1.66E-04 1.98E-04 1.82E-04 1.89E-04 1.97E-04 1.84E-04

Beryllium, Be Line emission factor (EF): 1.17E-06 lb/ton pellets

Mass recovered, ug 0.766 0.852 0.812 1.17 1.39 1.25

Stack emission, lb/hr 0.00031 0.00034 0.00032 0.00051 0.00060 0.00054

EF, lb/ton pellets fired 4.09E-07 4.52E-07 4.32E-07 6.79E-07 8.05E-07 7.24E-07

Cadmium, Cd Line emission factor (EF): 7.11E-07 lb/ton pellets

Mass recovered, ug 0.758 0.568 0.560 0.704 0.647 0.597

Stack emission, lb/hr 0.00030 0.00023 0.00022 0.00031 0.00028 0.00026

EF, lb/ton pellets fired 4.05E-07 3.01E-07 2.98E-07 4.08E-07 3.75E-07 3.46E-07

Chromium, Cr Line emission factor (EF): 1.08E-04 lb/ton pellets

Mass recovered, ug 73.2 80.1 68.1 122 123 113

Stack emission, lb/hr 0.029 0.032 0.027 0.053 0.053 0.049

EF, lb/ton pellets fired 3.91E-05 4.25E-05 3.62E-05 7.08E-05 7.09E-05 6.56E-05

Cobalt, Co Line emission factor (EF): 6.74E-06 lb/ton pellets

Mass recovered, ug 6.11 4.69 5.21 7.47 6.12 6.60

Stack emission, lb/hr 0.0024 0.0019 0.0021 0.0032 0.0027 0.0029

EF, lb/ton pellets fired 3.26E-06 2.49E-06 2.77E-06 4.33E-06 3.54E-06 3.82E-06

Lead, Pb Line emission factor (EF): 5.90E-05 lb/ton pellets

Mass recovered, ug 45.1 51.4 51.8 51.1 60.2 58.1

Stack emission, lb/hr 0.018 0.020 0.021 0.022 0.026 0.025

EF, lb/ton pellets fired 2.41E-05 2.73E-05 2.75E-05 2.96E-05 3.49E-05 3.37E-05

Manganese, Mn Line emission factor (EF): 7.04E-04 lb/ton pellets

Mass recovered,ug 445 478 399 830 820 778

Stack emission, lb/hr 0.178 0.190 0.159 0.36 0.36 0.34

EF, lb/ton pellets fired 2.37E-04 2.54E-04 2.12E-04 4.82E-04 4.75E-04 4.51E-04

Mercury, Hg Line emission factor (EF): 1.98E-05 lb/ton pellets

Mass recovered, ug 14.0 20.6 16.7 17.5 19.3 18.9

Stack emission, lb/hr 0.0056 0.0082 0.0066 0.0076 0.0084 0.0082

EF, lb/ton pellets fired 7.48E-06 1.09E-05 8.86E-06 1.01E-05 1.12E-05 1.10E-05

1. This is the latest stack testing for HAPs emissions from the pelletizer from the entire industry.
MPCA Report

Page 61

Table 24. HAPs Stack Testing1at National Steel Pellet Company in August 1999 (Continued)

Waste Gas Stack 2A Waste Gas Stack 2B

Method 29 (Continued) Run 1 Run 2 Run 3 Run 1 Run 2 Run 3

Nickel, Ni Line emission factor (EF): 4.94E-05 lb/ton pellets

Mass recovered, ug 168 19.5 20.3 29.1 19.1 16.5

Stack emission, lb/hr 0.067 0.0077 0.0081 0.013 0.0083 0.0071

EF, lb/ton pellets fired 8.97E-05 1.03E-05 1.08E-05 1.69E-05 1.11E-05 9.53E-06

Selenium, Se Line emission factor (EF): 1.02E-04 lb/ton pellets

Mass recovered, ug 95.4 96.2 94.7 87.3 87.3 88.6

Stack emission, lb/hr 0.038 0.038 0.038 0.038 0.038 0.038

EF, lb/ton pellets fired 5.09E-05 5.10E-05 5.04E-05 5.06E-05 5.05E-05 5.13E-05

PM (front half) Line emission factor (EF): 9.03E-01 lb/ton pellets

Mass recovered, ug 557700 688500 580700 990500 1038800 968600

Isokinetic variation, % 101.6 102.3 101.9 100.3 100.6 100.5

Stack emission, lb/hr 223 274 232 430 451 421

Concentration, gr/dscf 0.1024 0.1285 0.1062 0.1962 0.2098 0.1959

EF, lb/ton pellets fired 2.98E-01 3.65E-01 3.09E-01 5.74E-01 6.01E-01 5.61E-01

Waste Gas Stack 2A Waste Gas Stack 2B

Method 26A, 8/11/99 Run 1 Run 2 Run 3 Run 1 Run 2 Run 3

Sample volume, dscf 41.66 41.66 41.60 38.70 38.44 38.12

Stack gas flow, dscfm 248,828 252,969 253,317 254,637 254,733 251,045

Line rate, ton pellets/hr 749 749 749 749 749 749

HCl Line emission factor (EF): 3.10E-02 lb/ton pellets

Mass recovered, ug 13700 13700 13900 13400 15200 13300

Stack emission, lb/hr 10.8 11.0 11.2 11.7 13.3 11.6

EF, lb/ton pellets fired 1.44E-02 1.47E-02 1.49E-02 1.56E-02 1.78E-02 1.55E-02

HF Line emission factor (EF): 5.59E-02 lb/ton pellets

Mass recovered, ug 24500 25500 25500 24100 26400 24400

Stack emission, lb/hr 19.4 20.5 20.5 21.0 23.1 21.3

EF, lb/ton pellets fired 2.58E-02 2.73E-02 2.74E-02 2.80E-02 3.09E-02 2.84E-02

Cl2 Line emission factor (EF): < 4.46E-07 lb/ton pellets

Mass recovered, ug < 0.20 < 0.20 < 0.20 < 0.20 < 0.20 < 0.20

Stack emission, lb/hr < 1.58E-04 < 1.61E-04 < 1.61E-04 < 1.74E-04 < 1.75E-04 < 1.74E-04

EF, lb/ton pellets fired < 2.11E-07 < 2.14E-07 < 2.15E-07 < 2.32E-07 < 2.34E-07 < 2.33E-07

1. This is the latest stack testing for HAPs emissions from the pelletizer from the entire industry.
MPCA Report

Page 62

Table 24. HAPs Stack Testing1at National Steel Pellet Company in August 1999 (Continued)

Waste Gas Stack 2A Waste Gas Stack 2B

Others, 8/12/99 Run 1 Run 2 Run 3 Run 1 Run 2 Run 3

Sample volume, dscf 43.32 42.00 43.42 38.80 39.17 38.55

Stack gas flow, dscfm 257,226 260,312 258,814 262,212 257,287 256,680

Moisture, volume, wb 13.2% 11.2% 13.0% 12.2% 13.2% 12.2%

Heat, n.g., MMBtu/hr 212 180 200 212 180 200

Formaldehyde (Method 0011 – SW 846). Line emission factor (EF): 7.15E-04 lb/MMBtu

Mass recovered, ug 81 83 77 88 84 88

Stack emission, lb/hr 0.063 0.068 0.061 0.079 0.073 0.078

EF, lb/MMBtu 2.99E-04 3.78E-04 3.03E-04 3.72E-04 4.06E-04 3.87E-04

Benzene (Method 18) Line emission factor (EF): 4.17E-04 lb/MMBtu MW: 78.113

Conc., ppbv (wet) 7.2 35 11 4.6 5.2 3.0

Stack emission, lb/hr 0.026 0.125 0.040 0.017 0.019 0.011

EF, lb/MMBtu 1.23E-04 6.94E-04 1.99E-04 7.90E-05 1.04E-04 5.33E-05

Toluene (Method 18) Line emission factor (EF): 9.78E-05 lb/MMBtu MW: 92.140

Conc., ppbv (wet) 1.0 7.9 0.78 0.82 1.9 0.49

Stack emission, lb/hr 0.0043 0.0332 0.0033 0.0035 0.0081 0.0021

EF, lb/MMBtu 2.01E-05 1.85E-04 1.66E-05 1.66E-05 4.49E-05 1.03E-05

Hexane (Method 18) Line emission factor (EF): < 3.91E-05 lb/MMBtu MW: 86.177

Conc., ppbv (wet) < 0.96 0.93 < 0.96 < 0.96 < 1 < 0.98

Stack emission, lb/hr < 0.0038 0.0037 < 0.0038 < 0.0038 < 0.0040 < 0.0038

EF, lb/MMBtu < 1.81E-05 2.08E-05 < 1.92E-05 < 1.80E-05 < 2.21E-05 < 1.92E-05

1. This is the latest stack testing for HAPs emissions from the pelletizer from the entire industry.
MPCA Report

Page 63

Table 25. HAPs emission estimates for NSPC’s Phase II pelletizer 1

Pollutant Emission, 

ton/year

Emission 

factor

E.F. unit Emission factor source

Products of incomplete combustion based on annual heat input of 2,181,102 MMBtu/yr

Benzene 0.455 0.0042 lb/MMBtu NSPC, August 1999

Toluene 0.107 0.00010 lb/MMBtu NSPC, August 1999

Hexane < 0.043 < 0.00004 lb/MMBtu NSPC, August 1999

Formaldehyde 0.780 0.00072 lb/MMBtu NSPC, August 1999

Emissions which are related to production level—5,651,147 ton pellets/year & 1.05% fluxstone usage

Hydrogen chloride 87.5 0.03096 lb/ton pel. NSPC, August 1999

Hydrogen fluoride 158 0.05594 lb/ton pel. NSPC, August 1999

Metals at-pellet firing 3 Emission 

factor

E.F. unit Emission factor source

Antimony, Sb 0.011 1.97 ppb of pel. NSPC, August 1999

Arsenic, As 1.05 186 ppb of pel. NSPC, August 1999

Beryllium, Be 0.0033 0.583 ppb of pel. NSPC, August 1999

Cadmium, Cd 0.0020 0.355 ppb of pel. NSPC, August 1999

Chromium, Cr 0.306 54.2 ppb of pel. NSPC, August 1999

Cobalt, Co 0.019 3.37 ppb of pel. NSPC, August 1999

Lead, Pb 0.167 29.5 ppb of pel. NSPC, August 1999

Manganese, Mn 1.99 352 ppb of pel. NSPC, August 1999

Mercury, Hg 0.056 9.92 ppb of pel. NSPC, August 1999

Nickel, Ni 0.140 24.7 ppb of pel. NSPC, August 1999

Selenium, Se 0.287 50.8 ppb of pel. NSPC, August 1999

1. The algebraic symbol, “<” (less than), indicates that the emission factor was developed from a stack 

test for which the mass recovered was below the detection limit for that air pollutant.

2. Reference Method 29 is the stack testing method for the elements listed here. The emission factors 

(for example, 1.97 parts of antimony in weight per 1 billion parts of pellets fired) are derived from 

the August 1999 stack testing shown in Table 24.
MPCA Report

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Table 26. HAPs emission estimation for off-pellet firing processes at NSPC 1

Process group2 Ore Bentonite Greenballs Pellets hdl Ore Bentonite Greenballs Pellets hdl Year total

Year PM from Emission Inventory,3ton/year Sum of element emissions for process groups, ton/year

1995 142 65.0 537 1364 0.74 0.035 0.515 1.380E+00 2.67

1996 55.6 32.0 234 597 0.29 0.017 0.224 6.037E-01 1.13

1997 99.6 65.2 12.7 22.1 0.52 0.035 0.01 2.231E-02 0.59

Element Composition of elements, ppm by weight Individual element emissions, ton/year ’96 sum4

Antimony, Sb 8.07 1.00 4.41 0.414 4.48E-04 3.21E-05 1.03E-03 2.47E-04 1.76E-03

Arsenic, As 14.7 3.31 12.1 4.88 8.18E-04 1.06E-04 2.82E-03 2.92E-03 6.66E-03

Beryllium, Be 2.12 2.25 0.420 0.742 1.18E-04 7.20E-05 9.83E-05 4.43E-04 7.31E-04

Cadmium, Cd 1.05 0.233 0.280 0.028 5.84E-05 7.46E-06 6.55E-05 1.67E-05 1.48E-04

Chromium, Cr 23.5 5.80 24.2 23.6 1.31E-03 1.85E-04 5.67E-03 1.41E-02 2.13E-02

Cobalt, Co 10.0 3.23 3.83 7.06 5.53E-04 1.03E-04 8.97E-04 4.21E-03 5.77E-03

Lead, Pb 13.1 34.4 2.53 0.580 7.30E-04 1.10E-03 5.93E-04 3.46E-04 2.77E-03

Manganese, Mn 5107 479 903 968 2.84E-01 1.53E-02 2.11E-01 5.78E-01 1.09E+00

Mercury, Hg 5.06 0.012 0.130 0.002 2.81E-04 3.87E-07 3.04E-05 1.19E-06 3.13E-04

Nickel, Ni 7.04 5.83 3.43 5.64 3.92E-04 1.86E-04 8.04E-04 3.37E-03 4.75E-03

Selenium, Se 10.8 0.267 3.53 0.280 6.00E-04 8.52E-06 8.27E-04 1.67E-04 1.60E-03

Data source 5(a) (b) (c) (d)

1. Since average composition data are used (see footnote 4 below), tracking of values of below detection limits is difficult. Thus, the algebraic symbol 

“<”, which is used in Table 6 (see footnote 1 of Table 6), is omitted.

2. Process group is used here to simplify data presentation. The ore group includes coarse and fine crushing. The fired pellets group includes pellet 

stockpiling and loadout.

3. PM emissions, reported to the Emission Inventory, are not verified by MPCA staff.

4. Sum of element emissions in 1996 for off-pellet firing processes is also shown in Table 4. Those for 1995 & 1997 are omitted here to save space. 

All calculations were made using spreadsheets.

5. Composition data listed in this table are the average values reported by non-NSPC facilities. (a) For the ore group, the composition data are 

provided by Northshore Mining, Hibbing Taconite, Ispat-Inland, EVTAC, and Minnesota Geological Survey. (b) For the bentonite group, the 

composition data are provided by Northshore Mining and Hibbing Taconite. (c) For the greenballs group, the composition data are provided by 

Northshore Mining, Hibbing Taconite, and Ispat-Inland. (d) For the fired pellets group, the composition data are provided by Northshore Mining, 

Hibbing Taconite, Ispat-Inland, and EVTAC.
MPCA Report

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Table 27. PM10 testing results for NSPC’s Phase II pelletizer 1

Stack 2A (Method 201A&202; 10/22/97) Run 1 Run 2 Run 3 Average

Mass recovered, ug 62,800 49,500 59,400 57,233

Sample gas volume, dscf 39.38 33.66 34.4 35.81

Stack gas flow, dscfm 255,129 254,977 251,145 253,750

Isokinetic variation, % (MPCA calc.) 98.0 98.5 99.4 98.6

Stack emission, lb/hr 53.82 49.60 57.36 53.59

Concentration, gr/dscf 0.02461 0.02269 0.02665 0.02465

Line rate, 2long ton pellets/hour 622 622 622 622

Line emission factor, lb/ton pellets fired 0.15461 0.14249 0.16479 0.15396

Notes: This was an engineering, gas fired test. MPCA review letter is dated 12/12/97.

Stack 2B (Method 201A & 202; 8/1/97) Run 1 Run 2 Run 3 Average

Mass recovered, ug 84,600 94,000 71,300 83,300

Sample gas volume, dscf 33.92 33.10 34.22 33.75

Stack gas flow, dscfm 253,275 247,815 252,076 251,055

Isokinetic variation, % (MPCA calc.) 94.3 98.9 94.4 95.9

Stack emission, lb/hr 83.56 93.09 69.47 82.04

Concentration, gr/dscf 0.03849 0.04383 0.03215 0.03816

Line rate, 2long ton pellets/hour 622 622 622 622

Line emission factor, lb/ton pellets fired 0.24005 0.26743 0.19958 0.23569

Notes: This was an engineering, gas fired test. MPCA review letter is dated 10/15/97.

Stack 2B (Method 201A&202; 10/12/94) Run 1 Run 2 Run 3 Average

Mass recovered, ug 39,500 38,500 30,100 36,033

Sample gas volume, dscf 21.66 21.35 21.75 21.59

Stack gas flow, dscfm 242,840 243,330 244,830 243,667

Isokinetic variation, % 107.9 107.5 107.9 107.8

Stack emission, lb/hr 58.58 58.04 44.82 53.81

Concentration, gr/dscf 0.02814 0.02783 0.02136 0.02578

Line rate, long ton pellets/hour 618 618 618 618

Line emission factor, lb/ton pellets fired 0.16927 0.16771 0.12950 0.15549

Notes: This was an engineering, gas fired test. MPCA review letter is dated 12/6/94.

1. Phase II pelletizer has two stacks, 2A and 2B. For all the tests in this table, line emissions is 

assumed to be twice the stack emissions determined.

2. A conversion factor of 0.74 was assumed to estimate line production rate of fired pellets 

from the reported pelletizer feed rate of green balls.
MPCA Report

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Table 28. Reference Method 12 testing at Furnace 12 of Northshore Mining Company 1

Stack Hood exhst (1 of 3 stacks) Waste gas (1 of 2 stacks) Stack Hood exhst (1 of 3 stacks) Waste gas (1 of 2 stacks)

Test date: September 16-17, 1998 (three 2-hour runs)

Common data Run 1 Run 2 Run 3 Run 1 Run 2 Run 3 Run 1 Run 2 Run 3 Run 1 Run 2 Run 3

Sample, dscf 84.43 89.57 87.97 81.14 82.02 83.67 Cobalt, Co

Stack, dscfm 65474 67095 65368 61387 60998 62112 Mass recv,ug Bad data from waste gas samples

Ton pel./hr 210 210 210 217 217 217 Stack, lb/hr made it impossible to generate line emission factor

Multiplier 22.934 2.000 EF, lb/ton pel

Antimony, Sb Line emission factor: 1.12E-07 lb/ton pellets fired Lead, Pb Line emission factor: 4.57E-05 lb/ton pellets fired

Mass recv,ug 0.162 0.070 0.063 bad 0.040 0.006 Mass recv,ug 18.65 18.55 15.84 22.89 19.29 27.19

Stack, lb/hr 1.66E-05 6.94E-06 6.19E-06 3.93E-06 5.89E-07 Stack, lb/hr 1.91E-03 1.84E-03 1.56E-03 2.29E-03 1.90E-03 2.67E-03

EF, lb/ton pel 7.90E-08 3.30E-08 2.94E-08 1.81E-08 2.71E-09 EF, lb/ton pel 9.10E-06 8.74E-06 7.40E-06 1.06E-05 8.74E-06 1.23E-05

Arsenic, As Line emission factor: 9.93E-06 lb/ton pellets fired Manganese, Mn Line emission factor: 1.32E-04 lb/ton pellets fired

Mass recv,ug 5.034 5.385 8.116 2.177 0.648 1.557 Mass recv,ug 30.69 21.81 185.9 9.217 22.16 41.17

Stack, lb/hr 5.16E-04 5.34E-04 7.98E-04 2.18E-04 6.37E-05 1.53E-04 Stack, lb/hr 3.15E-03 2.16E-03 1.83E-02 9.22E-04 2.18E-03 4.04E-03

EF, lb/ton pel 2.46E-06 2.54E-06 3.79E-06 1.00E-06 2.94E-07 7.04E-07 EF, lb/ton pel 1.50E-05 1.03E-05 8.69E-05 4.25E-06 1.00E-05 1.86E-05

Beryllium, Be Line emission factor: < 1.02E-06 lb/ton pellets fired Mercury, Hg Line emission factor: 9.81E-07 lb/ton pellets fired

Mass recv,ug 0.580 0.739 0.667 < 0.023 < 0.026 0.263 Mass recv,ug 0.368 0.268 0.267 0.700 0.534 0.608

Stack, lb/hr 5.95E-05 7.32E-05 6.56E-05 < 2.30E-06 < 2.56E-06 < 2.58E-05 Stack, lb/hr 3.77E-05 2.66E-05 2.62E-05 7.01E-05 5.25E-05 5.97E-05

EF, lb/ton pel 2.83E-07 3.48E-07 3.12E-07 < 1.06E-08 < 1.18E-08 < 1.19E-07 EF, lb/ton pel 1.79E-07 1.26E-07 1.25E-07 3.23E-07 2.42E-07 2.75E-07

Cadmium, Cd Line emission factor: 2.96E-06 lb/ton pellets fired Nickel, Ni Line emission factor: 1.86E-05 lb/ton pellets fired

Mass recv,ug 2.829 1.480 0.861 0.710 0.528 0.513 Mass recv,ug 6.826 8.947 13.91 0.669 6.119 9.163

Stack, lb/hr 2.90E-04 1.47E-04 8.46E-05 7.11E-05 5.19E-05 5.04E-05 Stack, lb/hr 7.00E-04 8.87E-04 1.37E-03 6.70E-05 6.02E-04 9.00E-04

EF, lb/ton pel 1.38E-06 6.97E-07 4.02E-07 3.27E-07 2.39E-07 2.32E-07 EF, lb/ton pel 3.33E-06 4.22E-06 6.50E-06 3.08E-07 2.77E-06 4.15E-06

Chromium, Cr Line emission factor: 8.42E-05 lb/ton pellets fired Selenium, Se

Mass recv,ug 51.20 43.49 58.95 6.896 12.33 23.10 Mass recv,ug Samples were not analyzed

Stack, lb/hr 5.25E-03 4.31E-03 5.79E-03 6.90E-04 1.21E-03 2.27E-03 Stack, lb/hr for this element

EF, lb/ton pel 2.50E-05 2.05E-05 2.76E-05 3.18E-06 5.59E-06 1.04E-05 EF, lb/ton pel

1. There are three hood exhaust stacks connected to a common exhaust header, and two waste gas stacks connected to another common exhaust header. Samples for laboratory analysis were taken from 

one of the three hood exhaust stacks and one of the two waste gas stacks for all three tests presented in this table. Line emission factors were then generated by summing of stack emissions multiplied by 

the proper multipliers. In general, the multiplier is assumed to be 3 for the hood exhaust stack emission and 2 for the waste gas stack emission.

2. For this particular test, the other two hood exhaust stacks were probed for gas flow rates to actually determine the multiplier for the hood exhaust stack emission.
MPCA Report

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Table 28. Reference Method 12 testing at Furnace 12 of Northshore Mining Company 1(Continued)

Stack Hood exhst (1 of 3 stacks) Waste gas (1 of 2 stacks) Stack Hood exhst (1 of 3 stacks) Waste gas (1 of 2 stacks)

Test date: May 19-21, 1998 (three 1-hour runs)

Common data Run 1 Run 2 Run 3 Run 1 Run 2 Run 3 Run 1 Run 2 Run 3 Run 1 Run 2 Run 3

Sample, dscf 40.83 40.93 40.27 42.03 40.68 41.01 Cobalt, Co Line emission factor: < 2.44E-06 lb/ton pellets fired

Stack, dscfm 63097 63467 62167 64670 64820 66546 Mass recv,ug < 0.5 < 0.5 < 0.5 < 0.5 < 0.5 < 0.5

Ton pel./hr 205 205 205 222 222 222 Stack, lb/hr < 1.02E-04 < 1.03E-04 < 1.02E-04 < 1.02E-04 < 1.05E-04 < 1.07E-04

Multiplier 23 2 EF, lb/ton pel < 4.98E-07 < 5.00E-07 < 4.97E-07 < 4.59E-07 < 4.76E-07 < 4.84E-07

Antimony, Sb Line emission factor: < 9.77E-06 lb/ton pellets fired Lead, Pb Line emission factor: 9.49E-05 lb/ton pellets fired

Mass recv,ug < 2 < 2 < 2 < 2 < 2 < 2 Mass recv,ug 24 21 21 13 15 18

Stack, lb/hr < 4.09E-04 < 4.10E-04 < 4.08E-04 < 4.07E-04 < 4.22E-04 < 4.29E-04 Stack, lb/hr 4.91E-03 4.31E-03 4.29E-03 2.65E-03 3.16E-03 3.86E-03

EF, lb/ton pel < 1.99E-06 < 2.00E-06 < 1.99E-06 < 1.84E-06 < 1.90E-06 < 1.94E-06 EF, lb/ton pel 2.39E-05 2.10E-05 2.09E-05 1.19E-05 1.43E-05 1.74E-05

Arsenic, As Line emission factor: 2.27E-05 lb/ton pellets fired Manganese, Mn Line emission factor: 9.86E-05 lb/ton pellets fired

Mass recv,ug 6.9 6.1 6.2 1.7 1.4 2.6 Mass recv,ug 18 11 17 19 18 46

Stack, lb/hr 1.41E-03 1.25E-03 1.27E-03 3.46E-04 2.95E-04 5.58E-04 Stack, lb/hr 3.68E-03 2.26E-03 3.47E-03 3.87E-03 3.79E-03 9.87E-03

EF, lb/ton pel 6.87E-06 6.10E-06 6.17E-06 1.56E-06 1.33E-06 2.52E-06 EF, lb/ton pel 1.79E-05 1.10E-05 1.69E-05 1.75E-05 1.71E-05 4.46E-05

Beryllium, Be Line emission factor: < 1.46E-06 lb/ton pellets fired Mercury, Hg Line emission factor: < 2.60E-06 lb/ton pellets fired

Mass recv,ug < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 Mass recv,ug < 0.8 < 0.4 < 0.4 < 0.8 < 0.4 < 0.4

Stack, lb/hr < 6.13E-05 < 6.15E-05 < 6.13E-05 < 6.11E-05 < 6.32E-05 < 6.44E-05 Stack, lb/hr < 1.64E-04 < 8.20E-05 < 8.17E-05 < 1.63E-04 < 8.43E-05 < 8.59E-05

EF, lb/ton pel < 2.99E-07 < 3.00E-07 < 2.98E-07 < 2.76E-07 < 2.85E-07 < 2.91E-07 EF, lb/ton pel < 7.97E-07 < 4.00E-07 < 3.98E-07 < 7.35E-07 < 3.81E-07 < 3.88E-07

Cadmium, Cd Line emission factor: 4.68E-06 lb/ton pellets fired Nickel, Ni Line emission factor: 1.79E-05 lb/ton pellets fired

Mass recv,ug 0.8 1.0 1.0 1.0 1.0 1.0 Mass recv,ug 5 2 2 2 2 10

Stack, lb/hr 1.64E-04 2.05E-04 2.04E-04 2.04E-04 2.11E-04 2.15E-04 Stack, lb/hr 1.02E-03 4.10E-04 4.08E-04 4.07E-04 4.22E-04 2.15E-03

EF, lb/ton pel 7.97E-07 9.99E-07 9.95E-07 9.19E-07 9.51E-07 9.69E-07 EF, lb/ton pel 4.98E-06 2.00E-06 1.99E-06 1.84E-06 1.90E-06 9.69E-06

Chromium, Cr Line emission factor: 1.34E-04 lb/ton pellets fired Selenium, Se Line emission factor: 2.70E-05 lb/ton pellets fired

Mass recv,ug 35 35 39 12 11 17 Mass recv,ug 7.6 7.1 7.2 3.0 2.9 2.3

Stack, lb/hr 7.15E-03 7.18E-03 7.96E-03 2.44E-03 2.32E-03 3.65E-03 Stack, lb/hr 1.55E-03 1.46E-03 1.47E-03 6.11E-04 6.11E-04 4.94E-04

EF, lb/ton pel 3.49E-05 3.50E-05 3.88E-05 1.10E-05 1.05E-05 1.65E-05 EF, lb/ton pel 7.57E-06 7.10E-06 7.16E-06 2.76E-06 2.76E-06 2.23E-06

1. There are three hood exhaust stacks connected to a common exhaust header, and two waste gas stacks connected to another common exhaust header. Samples for laboratory analysis were taken from 

one of the three hood exhaust stacks and one of the two waste gas stacks for all three tests presented in this table. Line emission factors were then generated by summing of stack emissions multiplied by 

the proper multipliers. The multiplier is assumed generally to be 3 for the hood exhaust stack emission and 2 for the waste gas stack emission.

2. For this particular test, the generally assumed multipliers were used.
MPCA Report

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Table 28. Reference Method 12 testing at Furnace 12 of Northshore Mining Company 1(Continued)

Stack Hood exhst (1 of 3 stacks) Waste gas (1 of 2 stacks) Stack Hood exhst (1 of 3 stacks) Waste gas (1 of 2 stacks)

Test date: May 24-26, 1994 (three 1-hour runs)

Common data Run 1 Run 2 Run 3 Run 1 Run 2 Run 3 Run 1 Run 2 Run 3 Run 1 Run 2 Run 3

Sample, dscf 45.00 46.40 47.56 46.61 45.18 45.19 Cobalt, Co Line emission factor: < 2.52E-06 lb/ton pellets fired

Stack, dscfm 61729 62123 63041 61911 62396 62023 Mass recv,ug < 0.6 < 0.6 < 0.6 < 0.6 < 0.6 < 0.6

Ton pel./hr 213 213 213 213 213 213 Stack, lb/hr < 1.09E-04 < 1.06E-04 < 1.05E-04 < 1.05E-04 < 1.10E-04 < 1.09E-04

Multiplier 23 2 EF, lb/ton pel < 5.12E-07 < 4.99E-07 < 4.94E-07 < 4.95E-07 < 5.15E-07 < 5.12E-07

Antimony, Sb Line emission factor: < 1.26E-04 lb/ton pellets fired Lead, Pb Line emission factor: 3.23E-05 lb/ton pellets fired

Mass recv,ug < 30 < 30 < 30 < 30 < 30 < 30 Mass recv,ug 8.9 11.0 12.0 2.6 3.6 3.8

Stack, lb/hr < 5.44E-03 < 5.31E-03 < 5.26E-03 < 5.27E-03 < 5.48E-03 < 5.45E-03 Stack, lb/hr 1.61E-03 1.95E-03 2.10E-03 4.57E-04 6.58E-04 6.90E-04

EF, lb/ton pel < 2.56E-05 < 2.50E-05 < 2.47E-05 < 2.48E-05 < 2.58E-05 < 2.56E-05 EF, lb/ton pel 7.59E-06 9.15E-06 9.89E-06 2.15E-06 3.09E-06 3.24E-06

Arsenic, As Line emission factor: 1.13E-04 lb/ton pellets fired Manganese, Mn Line emission factor: 5.31E-05 lb/ton pellets fired

Mass recv,ug 44.0 23.0 54.0 7.9 8.9 3.4 Mass recv,ug 7.7 7.9 11.0 25 19 11

Stack, lb/hr 7.98E-03 4.07E-03 9.47E-03 1.39E-03 1.63E-03 6.17E-04 Stack, lb/hr 1.40E-03 1.40E-03 1.93E-03 4.39E-03 3.47E-03 2.00E-03

EF, lb/ton pel 3.75E-05 1.91E-05 4.45E-05 6.52E-06 7.64E-06 2.90E-06 EF, lb/ton pel 6.57E-06 6.57E-06 9.06E-06 2.06E-05 1.63E-05 9.38E-06

Beryllium, Be Line emission factor: < 2.52E-06 lb/ton pellets fired Mercury, Hg Line emission factor: 3.63E-06 lb/ton pellets fired

Mass recv,ug < 0.6 < 0.6 < 0.6 < 0.6 < 0.6 < 0.6 Mass recv,ug 0.21 0.18 0.49 0.43 4.30 0.36

Stack, lb/hr < 1.09E-04 < 1.06E-04 < 1.05E-04 < 1.05E-04 < 1.10E-04 < 1.09E-04 Stack, lb/hr 3.81E-05 3.19E-05 8.59E-05 7.56E-05 7.86E-04 6.54E-05

EF, lb/ton pel < 5.12E-07 < 4.99E-07 < 4.94E-07 < 4.95E-07 < 5.15E-07 < 5.12E-07 EF, lb/ton pel 1.79E-07 1.50E-07 4.04E-07 3.55E-07 3.69E-06 3.07E-07

Cadmium, Cd Line emission factor: < 3.36E-06 lb/ton pellets fired Nickel, Ni Line emission factor: 5.15E-04 lb/ton pellets fired

Mass recv,ug < 0.8 < 0.8 < 0.8 < 0.8 < 0.8 < 0.8 Mass recv,ug 41 77 140 110 240 180

Stack, lb/hr < 1.45E-04 < 1.42E-04 < 1.40E-04 < 1.41E-04 < 1.46E-04 < 1.45E-04 Stack, lb/hr 7.44E-03 1.36E-02 2.45E-02 1.93E-02 4.38E-02 3.27E-02

EF, lb/ton pel < 6.82E-07 < 6.66E-07 < 6.59E-07 < 6.61E-07 < 6.87E-07 < 6.83E-07 EF, lb/ton pel 3.50E-05 6.41E-05 1.15E-04 9.08E-05 2.06E-04 1.54E-04

Chromium, Cr Line emission factor: 1.10E-04 lb/ton pellets fired Selenium, Se Line emission factor: 1.54E-05 lb/ton pellets fired

Mass recv,ug 19 23 34 22 35 25 Mass recv,ug 2.1 2.6 2.6 6.2 5.3 5.1

Stack, lb/hr 3.45E-03 4.07E-03 5.96E-03 3.87E-03 6.39E-03 4.54E-03 Stack, lb/hr 3.81E-04 4.60E-04 4.56E-04 1.09E-03 9.68E-04 9.26E-04

EF, lb/ton pel 1.62E-05 1.91E-05 2.80E-05 1.82E-05 3.00E-05 2.13E-05 EF, lb/ton pel 1.79E-06 2.16E-06 2.14E-06 5.12E-06 4.55E-06 4.35E-06

1. There are three hood exhaust stacks connected to a common exhaust header, and two waste gas stacks connected to another common exhaust header. Samples for laboratory analysis were taken from 

one of the three hood exhaust stacks and one of the two waste gas stacks for all three tests presented in this table. Line emission factors were then generated by summing of stack emissions multiplied by 

the proper multipliers. The multiplier is assumed generally to be 3 for the hood exhaust stack emission and 2 for the waste gas stack emission.

2. For this particular test, the generally assumed multipliers were used.
MPCA Report

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Table 29. Element composition analysis from Northshore Mining Company (ppm by weight) 1

Material Antimony Arsenic Beryllium Cadmium Chromium Cobalt Lead Manganese Mercury Nickel Selenium

Sb As Be Cd Cr Co Pb Mn Hg Ni Se

Bentonite < 0.4 0.6 2.46 0.23 3.6 2.2 35.9 494 0.0121 2.5 < 0.2

Bentonite 1.52 3.49 2.1 0.22 3.9 1.9 32.5 345 6.1 < 0.3

Coal < 0.06 2.37 0.7 0.11 4.5 1.9 1.2 61 < 2.1 < 0.3

Coal < 1 < 1 2.06 < 0.5 7.8 13.8 1.3 10 0.0579 13.4 4.7

Coal ash 1.0 13.9 8.91 0.61 82.9 49.9 27.6 198 0.0242 51.6 8.9

Coal ash 1.42 11.21 6.3 1.81 74.0 29.6 40.4 180 57.4 6.2

Coarse tails 0.47 23.72 2.5 < 0.02 57.4 8.4 0.8 4813 3.7 < 0.3

Concentrate 0.21 5.07 0.6 < 0.02 41.5 9.3 < 0.5 919 6.4 0.4

Dry cob tails 0.23 37.08 1.7 < 0.02 56.4 6.1 0.8 3284 2.9 < 0.3

Fine tails 0.08 14.06 2.0 0.03 51.8 8.5 0.7 3811 2.8 < 0.3

Flux conc < 0.4 1.8 0.43 < 0.03 35.8 6.9 0.3 1821 0.0028 6.7 < 0.3

Flux pellets < 0.3 1.4 0.80 < 0.03 11.2 12.2 0.3 1347 0.0010 8.2 < 0.2

Flux stone 1.0 6.8 0.09 < 0.01 3.3 < 0.3 1.2 55 0.0070 0.6 < 0.1

Green balls 0.72 4.00 0.5 < 0.02 45.7 8.9 < 0.5 945 7.8 < 0.3

Lime stone < 0.06 2.67 < 0.2 0.03 1.7 < 0.8 1.1 31 < 2.1 < 0.3

Pellets, fired 0.66 3.69 0.6 < 0.02 42.1 9.4 0.6 814 8.3 < 0.3

Plant feed 3.62 7.54 2.2 < 0.02 47.0 8.7 < 0.5 2578 3.5 < 0.3

Starch binder < 0.06 2.24 0.4 0.13 < 0.6 1.0 1.4 23 2.6 < 0.3

Starch binder < 0.3 < 0.4 < 0.02 0.06 2.1 0.4 0.4 31 0.0011 0.9 < 0.2

Std conc 1 < 0.4 2.3 0.56 < 0.03 29.2 12.1 < 0.3 1568 0.0029 8.3 0.6

Std conc 2 < 0.3 1.2 0.37 < 0.02 43.1 9.9 < 0.2 1487 0.0032 11.7 < 0.3

Std pellets < 0.5 1.4 0.41 < 0.05 34.0 9.1 0.3 1347 0.0030 5.5 < 0.3

1. Data were collected March 1994 and March 1997. The algebraic symbol, “<”, indicates that the mass used in the analysis was below the detection limit.
MPCA Report

Page 70

Table 30. Testing for products of incomplet combustion at NMC’s Furnace 12 1

Line heat input 155 million Btu/hour

Multiplier 3 (1 of 3 hood exhaust stacks) 2 (1 of 2 waste gas stacks)

Common:23 PICs Run 1 Run 2 Run 3 Run 1 Run 2 Run 3

Sample volume, dscf 0.706 0.681 0.679 0.729 0.697 0.689

Stack gas flow, dscfm 68200 67800 67800 66100 63200 63200

Benzene Line emission factor: < 0.00098 lb/MMBtu

Mass recovered, ug < 2.4 < 2.4 < 2.4 < 2.4 < 2.4 < 2.4

Stack emission, lb/hr < 0.031 < 0.032 < 0.032 < 0.029 < 0.029 < 0.029

Toluene Line emission factor: < 0.00098 lb/MMBtu

Mass recovered, ug < 2.4 < 2.4 < 2.4 < 2.4 < 2.4 < 2.4

Stack emission, lb/hr < 0.031 < 0.032 < 0.032 < 0.029 < 0.029 < 0.029

Hexane Line emission factor: < 0.00106 lb/MMBtu

Mass recovered, ug < 2.6 < 2.6 < 2.6 < 2.6 < 2.6 < 2.6

Stack emission, lb/hr < 0.033 < 0.034 < 0.034 < 0.031 < 0.031 < 0.032

Formaldehyde Line emission factor: 0.02173 lb/MMBtu

Sample volume, dscf 58.01 58.07 57.92 54.48 52.41 51.86

Stack gas flow, dscfm 68201 68266 67832 66087 63202 62266

Mass recovered, ug 2700 2900 2700 6300 5700 7500

Stack emission, lb/hr 0.420 0.451 0.418 1.011 0.909 1.191

1. Test date: October 12, 1995.

2. There are three hood exhaust stacks connected to a common exhaust header, and 

two waste gas stacks connected to another common exhaust header. Samples were 

taken from one of the three hood exhaust stacks and one of the two waste gas stacks 

for all three tests presented in this table. Line emission factors were then generated 

by summing of stack emissions multiplied by the proper multipliers. The multiplier 

was assumed generally to be 3 for the hood exhaust stack emission and 2 for the 

waste gas stack emission.
MPCA Report

Page 71

Table 31. Stack testing for HCl and HF at NMC’s Furnace 12

Run 1 Run 2 Run 3 Run 1 Run 2 Run 3

Test date: Nov. 3, 1998 (Line prod. rate: 259 ton pellets/hour)

Multiplier 13 (1 of 3 hood exhaust stacks) 2 (1 of 2 waste gas stacks)

Sample volume, dscf 45.22 45.18 45.94 36.73 37.73 37.52

Stack gas flow, dscfm 69700 70391 70388 57928 57030 56964

HCl Line emission factor: 0.00614 lb/ton pellets fired

Mass recovered, ug 1615 1395 1235 1874.6 1654.6 1804.6

Stack emission, lb/hr 0.329 0.287 0.250 0.391 0.331 0.362

HF Line emission factor: 0.00186 lb/ton pellets fired

Mass recovered, ug 694 776 711 63 108 96

Stack emission, lb/hr 0.141 0.160 0.144 0.013 0.022 0.019

Test date: January 1992 (Line prod. rate: 284 ton pellets/hour) 2

Specific test date Jan. 7, 1992 Jan. 8, 1992

Sample volume, dscf 44.77 44.77 44.69 44.00 44.47 44.11

Stack gas flow, dscfm 60200 60200 60200 58700 58700 58700

HCl

Mass recovered, ug 8227 4988 4782 1142 1100 1142

Stack emission, lb/hr 1.463 0.887 0.852 0.201 0.192 0.201

HF

Mass recovered, ug 737 1464 1938 1948 1369 3106

Stack emission, lb/hr 0.131 0.260 0.345 0.344 0.239 0.547

Specific test date Jan. 9, 1992 Summary for

Sample volume, dscf 45.28 44.64 44.70 line emission factors:

Stack gas flow, dscfm 62500 62500 62500

HCl Line emission factor: 0.00768 lb/ton pellets fired

Mass recovered, ug 492.6 683.9 858.7

Stack emission, lb/hr 0.090 0.127 0.159

HF Line emission factor: 0.00562 lb/ton pellets fired

Mass recovered, ug 1158.3 1895.4 2106.0

Stack emission, lb/hr 0.212 0.351 0.390

1. There are three hood exhaust stacks connected to a common exhaust header, and 

two waste gas stacks connected to another common exhaust header. Samples were 

taken from one of the three hood exhaust stacks and one of the two waste gas stacks 

for all three tests presented in this table. Line emission factors were then generated 

by summing of stack emissions multiplied by the proper multipliers.

2. This testing work was the earliest found in the MPCA file. The hood exhaust stack 

appeared to be tested twice (1/7/92 & 1/9/92), while the waste gas stack was tested 

only once (1/8/92). Line emission factors resulted from averaging the data from all 

three days of testing.
MPCA Report

Page 72

Table 32. HAPs emission estimates for NMC’s taconite pelletizers 1

Pollutant Emission, 

ton/year

Emission 

factor

E.F. unit Emission factor source

Products of incomplete combustion based on annual heat input of 3,023,583 MMBtu/yr

Benzene < 1.48 < 0.00098 lb/MMBtu NMC 10/95

Toluene < 1.48 < 0.00098 lb/MMBtu NMC 10/95

Hexane < 1.61 < 0.00106 lb/MMBtu NMC 10/95

Formaldehyde 32.9 0.02173 lb/MMBtu NMC 10/95

Emissions which are related to production level — 4,524,800 ton pellets/year

Hydrogen chloride 17.4 0.00768 lb/ton pel. NMC 1/92

Hydrogen fluoride 12.7 0.00562 lb/ton pel. NMC 1/92

Metals at-pellet firing 2 Emission 

factor

E.F. unit Emission factor source

Antimony, Sb < 0.285 < 63.0 ppb of pel. NMC 5/94

Arsenic, As 0.255 56.3 ppb of pel. NMC 5/94

Beryllium, Be < 0.006 < 1.26 ppb of pel. NMC 5/94

Cadmium, Cd 0.011 2.34 ppb of pel. NMC 5/98

Chromium, Cr 0.303 67.0 ppb of pel. NMC 5/98

Cobalt, Co < 0.006 < 1.26 ppb of pel. NMC 5/94

Lead, Pb 0.215 47.4 ppb of pel. NMC 5/98

Manganese, Mn 0.298 65.8 ppb of pel. NMC 9/98

Mercury, Hg 0.008 1.82 ppb of pel. NMC 5/94

Nickel, Ni 1.164 257 ppb of pel. NMC 5/94

Selenium, Se 0.061 13.5 ppb of pel. NMC 5/98

1. The algebraic symbol, “<” (less than), indicates that the emission factor was developed from a stack 

test for which the mass recovered was below the detection limit for that air pollutant.

2. Reference Method 29 is the stack testing method for the elements listed here. See Table 28 for 

NMC’s emission factors. For example, for antimony, the emission factor is less than 63.0 parts of 

the element in weight per 1 billion parts of pellets fired from the May 1994 test.
MPCA Report

Page 73

Table 33. HAPs emission estimation for off-pellet firing processes at Northshore Mining Company

Process group1 Ore Bentonite Greenballs Fired pellets Coal handl Ore Bentonite Greenballs Fired pellets Coal handl Year total

Year PM from Emission Inventory,2ton/year Sum of element emissions for process groups, ton/year 

1995 966 10.1 58.5 6693 0.06 2.56 0.005 0.059 8.17 3.897E-06 10.8

1996 574 8.30 130 1748 0.03 1.52 0.004 0.132 2.13 1.949E-06 3.79

1997 723 11.2 131 5182 0.57 1.92 0.005 0.133 6.32 3.703E-05 8.38

Element Composition of elements,3

ppm by weight Individual element emissions, ton/year ‘97; sum:

4

Antimony, Sb 3.62 0.96 0.72 0.487 0.53 2.62E-03 1.07E-05 9.42E-05 2.52E-03 3.02E-07 5.24E-03

Arsenic, As 7.54 2.05 4.0 2.16 1.69 5.45E-03 2.29E-05 5.23E-04 1.12E-02 9.60E-07 1.72E-02

Beryllium, Be 2.2 2.28 0.5 0.60 1.38 1.59E-03 2.55E-05 6.54E-05 3.13E-03 7.87E-07 4.81E-03

Cadmium, Cd 0.02 0.23 0.02 0.03 0.31 1.45E-05 2.52E-06 2.62E-06 1.73E-04 1.74E-07 1.92E-04

Chromium, Cr 47.0 3.75 45.7 29.1 6.15 3.40E-02 4.19E-05 5.98E-03 1.51E-01 3.51E-06 1.91E-01

Cobalt, Co 8.7 2.05 8.9 10.2 7.85 6.29E-03 2.29E-05 1.16E-03 5.30E-02 4.47E-06 6.05E-02

Lead, Pb 0.5 34.2 0.5 0.40 1.25 3.61E-04 3.82E-04 6.54E-05 2.07E-03 7.13E-07 2.88E-03

Manganese, Mn 2578 420 945 1169 35.5 1.86E+00 4.69E-03 1.24E-01 6.06E+00 2.02E-05 8.05E+00

Mercury, Hg 0.11 0.0121 0.13 0.0020 0.0579 7.95E-05 1.35E-07 1.70E-05 1.04E-05 3.30E-08 1.07E-04

Nickel, Ni 3.5 4.3 7.8 7.33 7.75 2.53E-03 4.81E-05 1.02E-03 3.80E-02 4.42E-06 4.16E-02

Selenium, Se 0.3 0.25 0.3 0.27 2.50 2.17E-04 2.80E-06 3.92E-05 1.38E-03 1.43E-06 1.64E-03

Data source for Hg Ispat-Inland Ispat-Inland

1. Process group is used here to simplify data presentation. The ore group includes coarse and fine crushing. The fired pellets group includes pellet stockpiling and loadout.

2. PM emissions, reported to the Emission Inventory, are not verified by MPCA staff.

3. Except for mercury, composition data in this block are provided by NMC (Table 29).

4. Sum of element emissions in 1997 for off-pellet firing processes is also shown in Table 4. Those for 1995 & 1996 are omitted here to save space. All calculations were made 

using spreadsheets.
MPCA Report

Page 74

Table 34. PM testing results (Methods 5 & Minn.R. 7005.0500) for NMC’s pelletizers 1

Stack 1104 (waste gas; 7/31/96) Run 1 Run 2 Run 3 Average Remarks

Mass recovered, ug 33300 17300 14100 21567 MPCA review letter

Sample gas volume, dscf 43.40 41.45 41.86 42.24 (9/19/96) recognizes

Stack gas flow, dscfm 62176 60661 61312 61383 the stack tested is in

Isokinetic variation, % 101.9 99.7 99.6 100.4 compliance with the

Stack PM emission, lb/hour 6.31 3.35 2.73 4.13 PM emission limit of

PM concentration in stack gas, gr/dscf 0.0118 0.0064 0.0052 0.0078 0.01 gr/dscf in Permit

Line production rate, ton pellets/hour 311 311 311 311 No. 27A-89-OT-1.

Stack ems factor, lb/ton pellets (line) 0.02027 0.01076 0.00877 0.01327

Stack 1105 (waste gas; 7/31/96) Run 1 Run 2 Run 3 Average Remarks

Mass recovered, ug 18100 15600 16100 16600 MPCA review letter

Sample gas volume, dscf 42.76 41.59 42.11 42.15 (9/19/96) recognizes

Stack gas flow, dscfm 62573 60998 61764 61778 the stack tested is in

Isokinetic variation, % 99.7 99.5 99.5 99.6 compliance with the

Stack PM emission, lb/hour 3.50 3.03 3.12 3.22 PM emission limit of

PM concentration in stack gas, gr/dscf 0.0065 0.0058 0.0059 0.0061 0.01 gr/dscf in Permit

Line production rate, ton pellets/hour 296 296 296 296 No. 27A-89-OT-1.

Stack ems factor, lb/ton pellets (line) 0.01185 0.01024 0.01056 0.01088

Stack 1204 (waste gas; 7/30/96) Run 1 Run 2 Run 3 Average Remarks

Mass recovered, ug 22200 17300 16900 18800 MPCA review letter

Sample gas volume, dscf 39.16 40.47 41.03 40.22 (9/19/96) recognizes

Stack gas flow, dscfm 58484 60125 60740 59783 the stack tested is in

Isokinetic variation, % 99.1 99.6 100.0 99.6 compliance with the

Stack PM emission, lb/hour 4.39 3.40 3.31 3.70 PM emission limit of

PM concentration in stack gas, gr/dscf 0.0087 0.0066 0.0064 0.0072 0.01 gr/dscf in Permit

Line production rate, ton pellets/hour 315 315 315 315 No. 27A-89-OT-1.

Stack ems factor, lb/ton pellets (line) 0.01391 0.01078 0.01050 0.01173

Stack 1205 (waste gas; 7/30/96) Run 1 Run 2 Run 3 Average Remarks

Mass recovered, ug 13600 17000 16800 15800 MPCA review letter

Sample gas volume, dscf 38.31 38.12 38.39 38.27 (9/19/96) recognizes

Stack gas flow, dscfm 56746 56129 56134 56336 the stack tested is in

Isokinetic variation, % 99.9 100.5 101.2 100.5 compliance with the

Stack PM emission, lb/hour 2.66 3.31 3.25 3.08 PM emission limit of

PM concentration in stack gas, gr/dscf 0.0055 0.0069 0.0068 0.0064 0.01 gr/dscf in Permit

Line production rate, ton pellets/hour 318 318 318 318 No. 27A-89-OT-1.

Stack ems factor, lb/ton pellets (line) 0.00839 0.01043 0.01023 0.00968

1. For Furnaces 11 or 12, there are 3 hood exhaust stacks (Stacks 1101, 1102, and 1103; or Stacks 1201, 1202, 

1203) connected to a common exhaust header and 2 waste gas stacks connected to another common exhaust 

header (Stacks 1104 and 1105; or Stacks 1204 and 1205). Minn.R. 7005.0500 is for “organic wet catch.”
MPCA Report

Page 75

Table 34. PM testing results (Methods 5 & Minn.R. 7005.0500) for NMC’s pelletizers 1(Continued)

Stack 601 (Furnace 6; 10/10/95) Run 1 Run 2 Run 3 Average Remarks

Mass recovered, ug 23200 15100 22300 20200 MPCA review letter

Sample gas volume, dscf 37.62 37.61 37.71 37.65 (3/18/96) recognizes

Stack gas flow, dscfm 52507 52961 52937 52802 the stack tested is in

Isokinetic variation, % 99.9 99.0 99.3 99.4 compliance with the

Stack PM emission, lb/hour 4.28 2.81 4.14 3.75 PM emission limit of

PM concentration in stack gas, gr/dscf 0.0095 0.0062 0.0091 0.0083 0.01 gr/dscf in Permit

Line production rate, ton pellets/hour 123 123 123 123 No. 27A-89-OT-1.

Stack ems factor, lb/ton pellets (line) 0.03486 0.02289 0.03370 0.03049

Stack 1104 (waste gas; 1/10/95) Run 1 Run 2 Run 3 Average Remarks

Mass recovered, ug 39100 29600 20900 29867 MPCA review letter

Sample gas volume, dscf 51.28 51.49 51.63 51.47 (5/16/95) recognizes

Stack gas flow, dscfm 69343 69067 69437 69282 the stack re-tested 2is

Isokinetic variation, % 99.5 100.3 100.0 99.9 in compliance with the

Stack PM emission, lb/hour 6.99 5.25 3.72 5.32 PM emission limit of

PM concentration in stack gas, gr/dscf 0.0118 0.0089 0.0062 0.0090 0.01 gr/dscf in Permit

Line production rate, ton pellets/hour 319 319 319 319 No. 27A-89-OT-1.

Stack ems factor, lb/ton pellets (line) 0.02191 0.01645 0.01165 0.01667

Stack 1105 (waste gas; 1/10/95) Run 1 Run 2 Run 3 Average Remarks

Mass recovered, ug 34300 36600 37800 36233 MPCA review letter

Sample gas volume, dscf 51.68 52.66 51.00 51.78 (5/16/95) recognizes

Stack gas flow, dscfm 70316 72787 70134 71079 the stack re-tested 2is

Isokinetic variation, % 101.3 99.7 100.2 100.4 in compliance with the

Stack PM emission, lb/hour 6.17 6.69 6.88 6.58 PM emission limit of

PM concentration in stack gas, gr/dscf 0.0102 0.0107 0.0114 0.01 0.01 gr/dscf in Permit

Line production rate, ton pellets/hour 319 319 319 319 No. 27A-89-OT-1.

Stack ems factor, lb/ton pellets (line) 0.01934 0.02096 0.02154 0.02061

Stack 1204 (waste gas; 1/11/95) Run 1 Run 2 Run 3 Average Remarks

Mass recovered, ug 24000 18400 23300 21900 MPCA review letter

Sample gas volume, dscf 46.63 45.87 46.66 46.39 (5/16/95) recognizes

Stack gas flow, dscfm 63727 62512 63698 63312 the stack re-tested 2is

Isokinetic variation, % 99.8 100.1 99.9 99.9 in compliance with the

Stack PM emission, lb/hour 4.34 3.32 4.21 3.95 PM emission limit of

PM concentration in stack gas, gr/dscf 0.0079 0.0062 0.0077 0.0073 0.01 gr/dscf in Permit

Line production rate, ton pellets/hour 302 302 302 302 No. 27A-89-OT-1.

Stack ems factor, lb/ton pellets (line) 0.01435 0.01097 0.01391 0.01308

1. For Furnaces 11 or 12, there are 3 hood exhaust stacks (Stacks 1101, 1102, and 1103; or Stacks 1201, 1202, 

1203) connected to a common exhaust header and 2 waste gas stacks connected to another common exhaust 

header (Stacks 1104 and 1105; or Stacks 1204 and 1205). Minn.R. 7005.0500 is for “organic wet catch.”

2. The January 1995 performance testing of Stacks 1104, 1105, 1204, and 1205 was a re-test to resolve noncompliance issues associated with previous testing results (see next page). It should be noted that the 0.01 

gr/dscf limit is more stringent than the state’s PM rule.
MPCA Report

Page 76

Table 34. PM testing results (Methods 5 & Minn.R. 7005.0500) for NMC’s pelletizers 1(Continued)

Stack 1205 (waste gas; 1/11/95) Run 1 Run 2 Run 3 Average Remarks

Mass recovered, ug 29700 28100 27300 28367 MPCA review letter

Sample gas volume, dscf 45.96 46.81 45.07 45.95 (5/16/95) recognizes

Stack gas flow, dscfm 65952 63717 63698 64456 the stack re-tested 2is

Isokinetic variation, % 97.4 102.7 101.7 100.6 in compliance with the

Stack PM emission, lb/hour 5.64 5.06 5.10 5.27 PM emission limit of

PM concentration in stack gas, gr/dscf 0.0100 0.0093 0.0093 0.0095 0.01 gr/dscf in Permit

Line production rate, ton pellets/hour 302 302 302 302 No. 27A-89-OT-1.

Stack ems factor, lb/ton pellets (line) 0.01864 0.01673 0.01688 0.01742

Furnace 12 (5/25/94) Hood exhaust stack (1 of 3) Waste gas stack (1 of 2)

(Electrics ON) Run 1 Run 2 Run 3 Run 1 Run 2 Run 3

Mass recovered, ug 20900 29600 31400 124700 93900 79500

Sample gas volume, dscf 44.36 46.34 46.38 48.30 44.79 44.56

Stack gas flow, dscfm 62062 61536 61812 64551 62729 62059

Isokinetic variation, % 95.0 100.1 99.7 103.7 99.0 99.5

Stack PM emission, lb/hour 3.87 5.20 5.54 22.0 17.4 14.6

PM concentration in stack gas,2gr/dscf 0.0073 0.0099 0.0104 0.0398 0.0324 0.0275

Line production rate, ton pellets/hour 271 271 271 269 269 269

Stack ems factor, lb/ton pellets (line) 0.01427 0.01918 0.02042 0.08201 0.06472 0.05449

Line emission factor PM: 0.18802 lb/ton pellets fired from Furnace 12

Furnace 12 (5/24-25/94) Hood exhaust stack (1 of 3) Waste gas stack (1 of 2)

(Electrics OFF) Run 1 Run 2 Run 3 Run 1 Run 2 Run 3

Mass recovered, ug 30000 26200 30700 105100 131300 88200

Sample gas volume, dscf 47.68 47.37 46.83 44.34 44.26 44.06

Stack gas flow, dscfm 63577 62321 61825 61671 61752 61258

Isokinetic variation, % 99.6 101.0 100.6 99.7 99.3 99.7

Stack PM emission, lb/hour 5.29 4.56 5.36 19.3 24.2 16.2

PM concentration in stack gas, gr/dscf 0.0097 0.0085 0.0101 0.0366 0.0458 0.0309

Line production rate, ton pellets/hour 271 271 271 269 269 269

Stack ems factor, lb/ton pellets (line) 0.01952 0.01682 0.01978 0.07194 0.09015 0.06035

Line emission factor PM: 0.20441 lb/ton pellets fired from Furnace 12

1. For Furnaces 11 or 12, there are 3 hood exhaust stacks (Stacks 1101, 1102, and 1103; or Stacks 1201, 1202, 

1203) connected to a common exhaust header and 2 waste gas stacks connected to another common exhaust 

header (Stacks 1104 and 1105; or Stacks 1204 and 1205). Minn.R. 7005.0500 is for “organic wet catch.”

2. With the May 1994 stack testing, waste gas stacks (1104, 1105, and 1204) were found non-compliance with the 

PM emission limit of 0.01 gr/dscf in Permit No. 27A-89-OT-1. Re-test was conducted in January 1995 (see 

previous page). It should be noted that the 0.01 gr/dscf limit is more stringent than the state’s PM rule.
MPCA Report

Page 77

Table 34. PM testing results (Methods 5 & Minn.R. 7005.0500) for NMC’s pelletizers 1(Continued)

Stack 1104 (electrics on; 5/26/94) Run 1 Run 2 Run 3 Average Remarks

Mass recovered, ug 79000 258600 29900 122500 MPCA review letter

Sample gas volume, dscf 50.14 48.54 49.62 49.43 (1/11/95) notes that

Stack gas flow, dscfm 69427 66236 68343 68002 the stack tested 2is not

Isokinetic variation, % 98.7 100.2 99.2 99.4 in compliance with the

Stack PM emission, lb/hour 14.47 46.68 5.45 22.20 PM emission limit of

PM concentration in stack gas, gr/dscf 0.0243 0.0822 0.0093 0.0386 0.01 gr/dscf in Permit

Line production rate, ton pellets/hour 230 230 230 230 No. 27A-89-OT-1.

Stack ems factor, lb/ton pellets (line) 0.06302 0.20330 0.02373 0.09668

Stack 1105 (electrics on; 5/26/94) Run 1 Run 2 Run 3 Average Remarks

Mass recovered, ug 31300 25700 102900 53300 MPCA review letter

Sample gas volume, dscf 51.35 52.87 52.49 52.24 (1/11/95) notes that

Stack gas flow, dscfm 73739 73133 71070 72647 the stack tested 2is not

Isokinetic variation, % 95.2 98.8 100.9 98.3 in compliance with the

Stack PM emission, lb/hour 5.95 4.70 18.43 9.69 PM emission limit of

PM concentration in stack gas, gr/dscf 0.0094 0.0075 0.0303 0.0157 0.01 gr/dscf in Permit

Line production rate, ton pellets/hour 228 228 228 228 No. 27A-89-OT-1.

Stack ems factor, lb/ton pellets (line) 0.02602 0.02058 0.08066 0.04242

1. For Furnaces 11 or 12, there are 3 hood exhaust stacks (Stacks 1101, 1102, and 1103; or Stacks 1201, 1202, 

1203) connected to a common exhaust header and 2 waste gas stacks connected to another common exhaust 

header (Stacks 1104 and 1105; or Stacks 1204 and 1205). Minn.R. 7005.0500 is for “organic wet catch.”

2. With the May 1994 stack testing, waste gas stacks (1104, 1105, and 1204) were found non-compliance with the 

PM emission limit of 0.01 gr/dscf in Permit No. 27A-89-OT-1. Re-test was conducted in January 1995 (see 

previous page). It should be noted that the 0.01 gr/dscf limit is more stringent than the state’s PM rule.
MPCA Report

Page 78

Table 35. Inland’s voluntary stack testing (June 17-20, 1997) 1

HCl and HF

2 Run 1 Run 2 Run 3 Average

Sample volume, dscf

Stack A 47.60 47.92 46.91 47.48

Stack B 46.45 47.39 47.57 47.14

Stack C 48.44 47.67 47.31 47.81

Stack D 48.65 48.56 48.17 48.46

Stack gas flow, dscfm

Stack A 150762 150795 150006 150521

Stack B 149005 151650 150787 150481

Stack C 151818 151455 150446 151240

Stack D 140562 140719 142871 141384

Line rate, ton pellets/hr

Stack A 381 364 364 370

Stack B 384 384 384 384

Stack C 391 391 391 391

Stack D 370 347 370 362

HCl recovered, ug

Stack A 2777 4936 3908 3874

Stack B 6788 5451 5656 5965

Stack C 5245 5759 6171 5725

Stack D 535 617 679 610

HF recovered, ug

Stack A 1053 1474 1158 1229

Stack B 347 347 484 393

Stack C 495 548 611 551

Stack D < 105.3 < 105.3 < 105.3 < 105.3

HCl emission, lb/hr

Stack A 1.163 2.055 1.653 1.624

Stack B 2.880 2.307 2.372 2.520

Stack C 2.174 2.420 2.596 2.397

Stack D 0.2044 0.2365 0.2663 0.2357

HF emission, lb/hr

Stack A 0.4412 0.6136 0.4899 0.5149

Stack B 0.1474 0.1471 0.2031 0.1659

Stack C 0.2052 0.2301 0.2569 0.2307

Stack D < 0.0402 < 0.0404 < 0.0413 < 0.0406

HCl line emission factor 0.01776 lb/ton pellets fired

HF line emission factor < 0.00253 lb/ton pellets fired

1. Testing was conducted when the line was fired with natural gas.

2. Reference Method 26 was used for HCl and HF.
MPCA Report

Page 79

Table 35. Inland’s voluntary stack testing (June 17-20, 1997) 1(Continued)

PM10

2 Run 1 Run 2 Run 3 Average

Mass recovered, ug

Stack A 58200 59300 43400 53633

Stack B 29600 30500 21600 27233

Stack C 27400 21400 23000 23933

Stack D 21200 21300 20000 20833

Sample volume, dscf

Stack A 45.90 46.28 45.49 45.89

Stack B 45.50 43.83 43.89 44.41

Stack C 45.81 46.31 45.14 45.75

Stack D 44.32 43.62 43.62 43.85

Stack gas flow, dscfm

Stack A 148009 147135 145207 146784

Stack B 144969 143473 144634 144359

Stack C 150321 149600 145900 148607

Stack D 138928 140090 141327 140115

Isokinetic variation, %

Stack A 99.8 101.2 100.8 100.6

Stack B 101.0 98.3 97.7 99.0

Stack C 98.1 99.6 99.6 99.1

Stack D 101.7 99.3 98.4 99.8

Stack emission, lb/hr

Stack A 24.82 24.94 18.33 22.70

Stack B 12.48 13.21 9.416 11.70

Stack C 11.89 9.144 9.833 10.29

Stack D 8.790 9.049 8.571 8.804

PM10 conc., gr/dscf

Stack A 0.0196 0.0198 0.0147 0.0180

Stack B 0.0100 0.0107 0.0076 0.0095

Stack C 0.0092 0.0071 0.0079 0.0081

Stack D 0.0074 0.0075 0.0071 0.0073

Line rate, ton pellets/hr

Stack A 381 381 381 381

Stack B 403 403 384 397

Stack C 391 391 379 387

Stack D 370 347 370 362

PM10 line ems factor 0.1399 lb/ton pellets fired

1. Testing was conducted when the line was fired with natural gas.

2. Reference Methods 5 and 202 were used. Method 5 provided conservative estimates for 

PM10 for the “front half,” and Method 202 determined “condensibles” in the “back half.”
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Table 36. Inland’s engineering testing at Stack D (6/29-30/1994) 1

Ref. Method 29: Run 1 Run 2 Run 3 Average

Sample volume, dscf 44.09 42.21 42.64 42.98

Stack gas flow, dscfm 161349 149095 150526 153657

Antimony, Sb Line emission factor: < 2.67E-05 lb/ton pellets fired

Mass recovered, ug < 6 < 6 < 6 < 6

Stack emission, lb/hr < 2.90E-03 < 2.80E-03 < 2.80E-03 < 2.84E-03

Arsenic, As Line emission factor: 2.42E-05 lb/ton pellets fired

Mass recovered, ug 3.7 2.1 10.6 5.5

Stack emission, lb/hr 1.79E-03 9.81E-04 4.95E-03 2.57E-03

Beryllium, Be Line emission factor: < 1.33E-06 lb/ton pellets fired

Mass recovered, ug < 0.3 < 0.3 < 0.3 < 0.3

Stack emission, lb/hr < 1.45E-04 < 1.40E-04 < 1.40E-04 < 1.42E-04

Cadmium, Cd Line emission factor: 5.37E-06 lb/ton pellets fired

Mass recovered, ug 1.9 0.8 0.9 1.2

Stack emission, lb/hr 9.20E-04 3.74E-04 4.20E-04 5.71E-04

Chromium, Cr Line emission factor: 1.59E-05 lb/ton pellets fired

Mass recovered, ug 4.5 3.6 2.6 3.6

Stack emission, lb/hr 2.18E-03 1.68E-03 1.21E-03 1.69E-03

Cobalt, Co Line emission factor: < 1.33E-06 lb/ton pellets fired

Mass recovered, ug < 0.3 < 0.3 < 0.3 < 0.3

Stack emission, lb/hr < 1.45E-04 < 1.40E-04 < 1.40E-04 < 1.42E-04

Lead, Pb Line emission factor: 2.93E-04 lb/ton pellets fired

Mass recovered, ug 68.0 64.7 65.3 66.0

Stack emission, lb/hr 3.29E-02 3.02E-02 3.05E-02 3.12E-02

Manganese, Mn Line emission factor: 2.14E-04 lb/ton pellets fired

Mass recovered, ug 27.4 31.1 86.8 48.4

Stack emission, lb/hr 1.33E-02 1.45E-02 4.05E-02 2.28E-02

Mercury, Hg Line emission factor: 1.06E-05 lb/ton pellets fired

Mass recovered, ug 1.6 2.9 2.7 2.4

Stack emission, lb/hr 7.75E-04 1.35E-03 1.26E-03 1.13E-03

Nickel, Ni Line emission factor: 4.08E-05 lb/ton pellets fired

Mass recovered, ug 9.6 13.1 4.8 9.2

Stack emission, lb/hr 4.65E-03 6.12E-03 2.24E-03 4.34E-03

Selenium, Se Line emission factor: 1.54E-05 lb/ton pellets fired

Mass recovered, ug 3.3 3.4 3.7 3.5

Stack emission, lb/hr 1.60E-03 1.59E-03 1.73E-03 1.64E-03

1. Stack D is at the “hot side” (windbox) of the common exhaust header. Line rate of 

production was 426 ton pellets fired/hour. Line emission factors are calculated 

with a multiplier value of 4 for emission conversion from Stack D to the line.
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Table 36. Inland’s engineering testing at Stack D (6/29-30/1994) 1(Continued)

For HCl & Fluorides: Run 1 Run 2 Run 3 Average

Stack gas flow, dscfm 138119 153177 145425 145574

Ref. Method 26 (HCl) Line emission factor: 0.08049 lb/ton pellets fired

Mass recovered, ug 4217 710 720 1882

Sample volume, dscf 4.114 3.921 4.196 4.077

Stack emission, lb/hr 18.7 3.67 3.30 8.56

R.M.13B (Fluorides) Line emission factor: 1.47E-05 lb/ton pellets fired

Mass recovered, ug 2 7 3 4

Sample volume, dscf 47.21 50.94 50.25 49.47

Stack emission, lb/hr 0.00077 0.00278 0.00115 0.00157

Particulate Matter 2 Line emission factor: 0.1709 lb/ton pellets fired

Mass recovered, ug 55300 43200 43200 47233

Sample volume, dscf 52.09 51.88 50.68 51.55

Stack gas flow, dscfm 151973 150280 147836 150030

Isokinetic variation, % 101.5 102.2 101.5 101.7

Stack emission, lb/hr 21.34 16.55 16.67 18.19

Concentration, gr/dscf 0.01638 0.01285 0.01315 0.01413

1. Stack D is at the “hot side” (windbox) of the common exhaust header. Line rate of 

production was 426 ton pellets fired/hour. Line emission factors are calculated with 

a multiplier value of 4 for emission conversion from Stack D to the line.

2. PM emission rate was determined with Method 5 for both “front half” and “back 

half”. The “back half” was analyzed for “organic wet catch” as per Minn. R. 

7011.0725.

Table 37. Composition analysis from Inland 1

Element Fluxed pellets Green balls Ore composite

Antimony, Sb < 12 < 12 < 12

Arsenic, As < 20.2 < 20.2 < 20.2

Beryllium, Be 1.1 0.06 0.8

Cadmium, Cd < 0.8 < 0.8 < 0.8

Chromium, Cr < 1.0 < 1.0 < 1.0

Cobalt, Co 0.8 0.9 6.9

Lead, Pb < 6 < 6 < 6

Manganese, Mn 330 1080 4700

Mercury, Hg 0.08 0.13 0.11

Nickel, Ni < 0.4 < 0.4 1.5

Selenium, Se < 10 < 10 < 10

1. Samples were collected on 7/1/1994 and analyzed on 7/6/1994, except for 

mercury, which was analyzed on 7/7/1994.
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Table 38. Predicting HCl emissions from fluxstone fraction in fired pellets for some pelletizers 1

Input Data for Linear Regression Regression Statistics

Fluxstone fraction HCl, lb/ton Source Multiple R 0.76876

0 0.00395 HTC96L2 R^2 0.59099

0.01 0.00768 NMC 92 Adj. R^2 0.38649

0.0738 0.00614 NMC 98 Std Error 0.00479

0.10346 0.01776 Inland 97 Observations 4

Analysis of Variance (ANOVA)

df SS MS F Significance F

Regression 1 6.622E-05 6.622E-05 2.8899 0.23124

Residual 2 4.853E-05 2.291E-05

Total 3 0.000112

Coeff Std Error t Stat P-value Lower 95% Upper 95%

Intercept 0.00448 0.00353 1.26983 0.33190 -0.01070 0.01965

Fluxstone fraction 0.09407 0.05533 1.69997 0.23124 -0.14402 0.33215

1. The fitted model presented in detail here is for equation [1] of package 2 of this report. Since the data points 

were for the wet scrubber or wet ESP controlled pelletizers, the fitted model can be applied only to pelletizers 

with wet control devices. Extending the application of the fitted model to pelletizers with dry control devices 

(multiclones or gravity collectors) is not appropriate. For pelletizers with dry control devices, testing results 

from National Steel Pellet Company in August 1999 may be used to derive HCl emission factors.
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Table 39. HAPs emission estimates for Ispat-Inland’s taconite pelletizer 1

Pollutant Emission, 

ton/year

Emission 

factor

E.F. unit Emission factor source

Products of incomplete combustion based on annual heat input of 1,431,704 MMBtu/yr

Benzene < 2.63 < 0.00206 lb/MMBtu HTC 7/96

Toluene < 2.92 < 0.00229 lb/MMBtu HTC 7/96

Hexane < 2.63 < 0.00206 lb/MMBtu HTC 7/96

Formaldehyde 15.6 0.02173 lb/MMBtu NMC 10/95

Emissions which are related to production level—3,020,267 ton pellets/year

Hydrogen chloride 26.8 0.01776 lb/ton pel. Inland 97

Hydrogen fluoride < 3.82 < 0.00253 lb/ton pel. Inland 97

Metals at-pellet firing 2 Emission 

factor

E.F. unit Emission factor source

Antimony, Sb < 0.040 < 13.3 ppb of pel. Inland 94

Arsenic, As 0.037 12.1 ppb of pel. Inland 94

Beryllium, Be < 0.002 < 0.666 ppb of pel. Inland 94

Cadmium, Cd 0.008 2.68 ppb of pel. Inland 94

Chromium, Cr 0.024 7.95 ppb of pel. Inland 94

Cobalt, Co < 0.002 < 0.666 ppb of pel. Inland 94

Lead, Pb 0.443 147 ppb of pel. Inland 94

Manganese, Mn 0.323 107 ppb of pel. Inland 94

Mercury, Hg 0.016 5.31 ppb of pel. Inland 94

Nickel, Ni 0.062 20.4 ppb of pel. Inland 94

Selenium, Se 0.023 7.70 ppb of pel. Inland 94

1. The algebraic symbol, “<” (less than), indicates that the emission factor was developed from a stack 

test for which the mass recovered was below the detection limit for that air pollutant.

2. Reference Method 29 is the stack testing method for the elements listed here. See Table 36 for 

Inland’s emission factors.
MPCA Report

Page 84

Table 40. HAPs emission estimation for off-pellet firing processes at Ispat-Inland 1

Process group2 Ore Bentonite Greenballs Pellets hdl Ore Bentonite Greenballs Pellets hdl Year total

Year PM from Emission Inventory,3ton/year Sum of element emissions for process groups, ton/year

1995 57.8 2.49 41.3 547 0.27 0.001 0.047 2.090E-01 0.532

1996 57.1 2.47 40.8 540 0.27 0.001 0.046 2.064E-01 0.526

1997 123 0.02 33.1 1366 0.58 0.000 0.04 5.225E-01 1.14

Element Composition of elements, ppm by weight Individual element emissions, ton/year ’95 sum 4

Antimony, Sb 12.0 1.00 12.0 12.0 6.93E-04 2.50E-06 4.95E-04 6.56E-03 7.75E-03

Arsenic, As 20.2 3.31 20.2 20.2 1.17E-03 8.24E-06 8.34E-04 1.10E-02 1.31E-02

Beryllium, Be 0.800 2.25 0.060 1.10 4.62E-05 5.61E-06 2.48E-06 6.01E-04 6.56E-04

Cadmium, Cd 0.800 0.233 0.800 0.800 4.62E-05 5.81E-07 3.30E-05 4.37E-04 5.17E-04

Chromium, Cr 1.00 5.80 1.00 1.00 5.78E-05 1.44E-05 4.13E-05 5.47E-04 6.60E-04

Cobalt, Co 6.90 3.23 0.900 0.800 3.99E-04 8.05E-06 3.72E-05 4.37E-04 8.81E-04

Lead, Pb 6.00 34.4 6.00 6.00 3.47E-04 8.57E-05 2.48E-04 3.28E-03 3.96E-03

Manganese, Mn 4700 479 1080 330 2.72E-01 1.19E-03 4.46E-02 1.80E-01 4.98E-01

Mercury, Hg 0.110 0.012 0.130 0.080 6.35E-06 3.01E-08 5.37E-06 4.37E-05 5.55E-05

Nickel, Ni 1.50 5.83 0.400 0.400 8.67E-05 1.45E-05 1.65E-05 2.19E-04 3.36E-04

Selenium, Se 10.0 0.267 10.0 10.0 5.78E-04 6.64E-07 4.13E-04 5.47E-03 6.46E-03

Data source NMC; HTC

1. Since average composition data are used for bentonite, tracking of values of below detection limits is difficult. Thus, the algebraic symbol “<”, 

which is used in Table 39 (see footnote 1 of Table 39), is omitted.

2. Process group is used here to simplify data presentation. The ore group includes coarse and fine crushing. The fired pellets group includes pellet 

stockpiling and loadout.

3. PM emissions, reported to the Emission Inventory, are not verified by MPCA staff.

4. Sum of element emissions in 1995 for off-pellet firing processes is also shown in Table 4. Those for 1996 & 1997 are omitted here to save space. 

All calculations were made using spreadsheets.