~ 

ASARCO 'iii GRUPO MEXICO 

July 11, 2013 

Sent Email and Certified Mail 

Certified Mail No.: 7011 3500 0003 5438 8053 

Mr. Thomas Webb 

U.S. EPA, Region IX 

Planning Office, Air Division 

75 Hawthorne Street (AIR-2) 

San Francisco, CA 94105 

Re: 	 Response to·EPA Information Request dated June 27,2013 

ASARCO LLC - Hayden Operations 

Dear Mr. Webb: 

This letter responds to the U.S. Environmental Protection Agency, Region IX ("EPA") 

request to ASARCO LLC-Hayden Operations ("Asarco" or "Hayden") dated June 27, 

2013, in which EPA seeks additional information to assist it in performing a best 

available retrofit technology ("BART") analysis pursuant to the regional haze rule and its 

pending partial approval and partial disapproval of the Arizona State Implementation 

Plan ("SIP"). In its letter, EPA states that it is evaluating whether planned upgrades at 

the Hayden Smelter for purposes of complying the 1-hour S02 National Ambient Air 

Quality Standards ("NAAQS") may meet the requirements for BART. 

EPA has established a deadline for this response of July 12, 2013 for all control options 

that were "considered" (defined as "contemplated ... through any planning process 

resulting in any written analysis") during Asarco's extensive design review for the 

Hayden Smelter's planned converter retrofit project ("CRP"), which is the project that 

Asarco has identified to assist in ensuring compliance with the 1-hour S02 NMQS. 

Asarco has provided the information that it can in the time available, but it has focused 

its efforts on those options that its design engineer, Gas Cleaning Technologies, LLC 

("GCT"), identified as potentially applicable to the Hayden Smelter. 

Asarco is providing information responsive to each of EPA's requests. In addition, 

because EPA indicated that it is seeking to conduct its own BART determination, 

Asarco is providing a summary BART determination that it had started, but discontinued 

after the Arizona Department of Environmental Quality ("ADEQ") expressed its 

understanding that EPA was looking to defer the S02 BART determinations to the 1­

hour S02 NMQS implementation. We have included and slightly updated that 

100 Hayden Avenue. P.O. Box 8 • Hayden Arizona 85135 Telephone: 520.356.7811 
Response to EPA Information Request dated June 27,2013 

A8ARCO LLC-Hayden Operations 

July 11, 2013 

Page 2 

discussion for EPA's consideration. Asarco acknowledges that it is not as complete as 

it could be, but there was not time to complete the analysis at Asarco's preferred level of 

detail in the time provided. 

Asarco's Response to EPA Information Request 

Asarco has reprinted each part of EPA's information request in boldface type. Asarco's 

response appears in regular type. 

1. 	 Identify and describe any design improvements, upgrades to existing 

equipment, or new equipment which A5ARCO, or an entity working on 

behalf of A5ARCO, has considered that have the potential to increase the 

quantity of converter 502 emissions that are captured and vented to 

primary and secondary converter hooding. 

Asarco response: 

Asarco contracted with GCT to identify design improvements and upgrades to existing 

equipment or new equipment that have the potential to increase the quantity of 

converter 802 emissions that are captured and vented to primary and secondary 

converter hooding. GCT undertook a comprehensive study and considered the 

following modifications referred to as the Converter Retrofit Project or CRP: 

• 	 a converter process change to replace the existing five converters with three 

larger converters, allowing one converter blowing instead of two at a time. 

• 	 installing new tighter primary and secondary hoods to fit the new converters 

and provide greater capture efficiency. 

• 	 sending secondary hood exhaust from the blowing converter to the acid plant 

to increase sulfur fixation. 

• 	 modifying the converter primary gas system to suit the new converters and 

improve hood capture efficiency by installing individual spray coolers and a 

common ESP to' reduce system air infiltration. 

Both GCT and Asarco view the items above as one solution considered. The individual 

modi'fications cannot really be broken down into individual capture contributions since it 

is not practical to do anyone modification without the other modifications. 

Asarco has also considered EPA's suggestion that total flow to the acid plant be 

increased. This solution is not technically appropriate for the present equipment 

configuration because there is not sufficient strong 802gas to effectively operate 

additional acid plant capacity without increasing overall smelter capacity. The proposed 

CRP balances the existing strong 802gas generation capacity with acid plant capacity, 

which is preferable to an unbalanced system. Because additional acid plant capacity 

would not be helpful, no further work was carried out on this alternative. 
Response to EPA Information Request dated June 27,2013 

ASARCO LLC-Hayden Operations 

July 11, 2013 

Page 3 

a. 	 For each item identified in No.1 above, please include the estimated 

quantity of 502 that would be captured by the primary and secondary 

converter hoods following implementation of said item. Please 

provide this. estimate in terms of tons/year, as well as maximum Ib/hr 

and maximum Ib/day. 

Asarco Response: 

The CRP is expected to increase the amount of S02 captured by the primary and 

secondary hoods on a PTE long-term basis by 58 tons/yr from 166,085 to 166,143 

tons/yr. Most irrlportantly, it is expected to increase the amount of S02 captured by the 

primary and secondary hoods that is sent to the acid plant for S02 control from 143,849 

to 165,205 tons/yr. 

As noted above, the CRP is a holistic solution for sulfur capture and fixation that is not 

easily split among its various components. For purposes of air permitting, Asarco has 

developed the following estimates. These estimates differ slightly fron1 the design 

specifications set forth in the preceding paragraph due to the interactions between the 

pieces of equipment and rounding differences. 

o 	 Total S02 for converting and anode operations was estimated as follows. 

Using an assumed 60/40 split of sulfur loss in flash versus converting (and 

subsequent) operations, and deducting sulfur from anode operations, this 

results in the following emissions captured: 

• 	 Total tons S02 converting and anode operations =693,500 tons 

concentrate/yr * 0.3 S * 0.4 converting/anode ops fraction * 2 S to 

S02 = 166,440 tons/yr 

• 	 Total tons S02 anode operations =600 anode tons/day * 0.41 

Ib/ton * 365 days/yr * 1 ton/2000 Ibs =44.9 tons/yr 

• 	 Total tons S02 for converter operations = 166,440 - 44.9 = 

166,395.1 tons/yr 

• 	 Total tons S02 for converter secondary operations =693,500 

concentrate tons/yr * 0.3 S * 0.0025 converter secondary ops * 2 S 

to S02 =1040.3 tons/yr 

• 	 Total tons S02 for converter blowing operations =166,395.1 ­

1040.3 = 165,354.8 tons/yr 

o 	 Approximate primary hood capture. After CRP implementation, the 

primary hood system should achieve a conservative design capture rate of 

97%, with a short term worst case capture rate of 93% and a best case 

rate approaching 100% (used 99.9%). 

• 	 Tons/year = 160,394.2 (165,354.8 tons/yr * 0.97 capture) 

• 	 Max Ib/hr: 63,400 (from GCT) 
Response to EPA Information Request dated June 27, 2013 

A8ARCO LLC-Hayden Operations 

July 11, 2013 

Page 4 

• 	 Design Ib/hr (970/0): 36,619.7 (160,394.2 tons/yr * 2000 Ib/8760 hr) 

• 	 Max Ib/day: 881,000 (from GCT) 

• 	 Design Ib/day (970/0): 878,872.8 (36,619.7 * 24) 

o 	 Approxinlate secondary hood capture. After implementation, the 

secondary hood system should achieve a conservative design capture 

rate of 97% for blowing emissions, with a short term worst case capture 

rate of 93% for blowing emissions, and 900/0 capture of converter 

secondary operation emissions. 

• 	 Tons/year: 5,748.1 ((165,354.8 * (1-0.97 primary capture) * 0.97 

secondary capture (blowing errlissions) + 1040.3 tons * 0.90 

capture (converter secondary» 

• 	 Max Ib/hr: 4607.4 ((63,400 Ib/hr * (1-0.93) capture blowing Ib/hr * 

0.99 capture) + (1040.3 ton/yr converter secondary * 0.9 capture * 

2000 Ibs/8760 hrs) 

• 	 Design Ib/hr (970/0): 1,312.4 (5748.1 tons/yr * 2000 Ib/8760 hr) 

• 	 Min Ib/hr (930/0): 1,267.0 (165,354.8 tons/yr * (1-0.97 primary 

capture) * 0.93 secondary capture * 2000 Ibs/8760 hrs) + (1040.3 

ton/yr converter secondary * 0.9 capture * 2000 Ib/8760 hrs) 

b. 	 For each item identified in No.1 above, please also include the 

estimated quantity of 802 that would be left uncaptured by the 

primary and.secondary hoods following implementation of said item. 

Please provide this estimate in terms of tons/year, as well as 

maximum Ib/hr and maximum Ib/day. 

Asarco Response: 

The CRP is expected to decrease the amount of 802 not captured by the primary and 

secondary hoods on a PTE long-term annual basis by 58 tons/yr from 310 to 252 

tons/yr. Most importantly, it is expected to decrease the amount of 802 not captured by 

the primary and secondary hoods and sent to the acid plant by 21,356 tons/yr "from 

22,546 to 1,190 tons/yr, primarily by routing secondary hood emissions during blowing 

to the acid plant instead of the secondary hood baghouse. 

As noted above, the CRP is a holistic solution for sulfur capture and fixation that is not 

easily split among its various components. For purposes of air permitting, Asarco has 

developed the following estimates. These estimates differ slightly from the design 

specifications set forth in the preceding paragraph due to the interactions between the 

pieces of equipment and rounding differences. 

• 	 Approximate primary hood loss. After implementation, this should achieve a 

conservative design capture rate of 970/0, with a short term worst case capture 

rate of 930/0. 
Response to EPA Information Request dated June 27,2013 

ASARCO LLC-Hayden Operations 

July 11 , 2013 

Page 5 

o 	 Tons/year: 4,960.6 (165,354.8 tons/yr * (1-0.97) (to secondary hoods) 

o 	 Max Ib/hr (at 93%): 2,642.7 (165,354.8 tons/yr * (1-0.93 capture) * 2000 

Ibs/8760 hrs) 

o 	 Design Ib/hr (at 97%): 1,132~8 (165,354.8 tons/yr * 0.03 capture * 2000 

Ibs/8760 hrs) 

o 	 Max Ib/day (at 930/0 for 3 hours): 31,716.9 (21 hr * 1,132.8 Ib/hr + 3 hr * 

2,642.7Ib/hr) 

o 	 Design Ib/day (at 97%): 27,187.2 (24 hr * 1,132.8 Ib/hr) 

• 	 Approximate secondary hood loss. After implementation, this should achieve a 

conservative design capture rate of 97%, with a short term worst case capture 

rate of 93% plus 900/0 capture of converter secondary operations. 

o 	 Tons/year: 252.8 (4960.6 tons/yr blowing * (1-0.97 secondary capture) + 

1040.3 * (1-0.9» (to tertiary) 

o 	 Max Ib/hr (at 930/0): 103.0 (1132.8 Ib/hr * (1-0.93 secondary capture) + 

1040.3 * (1-0.9) * 2000 Ibs/8760 hr) 

o 	 Design Ib/hr (at 97%): 57.7 (252.8 tons/yr * 2000 Ibs/8760 hrs) 

o 	 Max Ib/day: 2,090.7 (103.0 Ib/hr * 3 hr/day + 57.7 Ib/hr * 21 hr/day + 

1040.3 ton/yr secondary * (1-0.9 secondary capture) * 2000 Ibs/8760 hr * 

24 hr/day) 

o 	 Design Ib/day (at 970/0): 1,385.2 (252.8 tons/yr * 2000 Ibs/8760 hr * 24 

hr/day) 

c. 	 For each item identified in No.1 above, please include the 

supporting calculations used to determine the quantity of 502 

captured by the primary and secondary converter hoods following 

the implementation of said item. If such calculations are available in 

an electronic format, such as a spreadsheet program like Excel or 

process simulator output, provide the supporting calculations in said 

electronic format. 

Asarco Response: 

Asarco's revised spreadsheet page for S02 emissions for the pending CRP permit 

application (as revised) is attached. This provides the basic numbers used above. The 

93% values were derived by substituting them in lieu of the 970/0 values shown. 

Calculations are shown above. This was done by hand. Some numbers were provided 

by GCT and are mostly identified as such. 

As noted above, the CRP is a holistic solution for sulfur capture and fixation that is not 

easily split among its various components. For purposes of air permitting, Asarco has 

developed the preceding estimates. These estimates differ slightly from the design 

specifications set forth in the preceding paragraphs due to the interactions between the 
Response to EPA Information Request dated June 27, 2013 

ASARCO LLC-Hayden Operations 

July 11, 2013 

Page 6 

pieces of equipment and rounding differences. They also differ slightly from those 

previously submitted to AOEQ and will be updated in a supplemental application. 

d. 	 For each item identified in No.1 above, please provide the purchased 

equipment cost, installation costs, and operating and maintenance 

costs associated with said control option. 

Asarco Response: 

The total installed (supply plus installation) cost for the considered solution is 

$95,700,000. Operating and maintenance costs are expected to be similar to current 

operation. 

2. 	 Identify and describe any design improvements, process improvements, or 

new equipment which A8ARCO, or an entity working on behalf of A8ARCO, 

considered that have the potential to capture converter 802 emissions that 

are not able to be captured by the primary or secondary converter hoods. 

Asarco Response: 

For improvements to capture S02 emissions that are not able to be captured by the 

primary and secondary converter hoods, we have considered partial enclosure of the 

converter aisle and installation of tertiary hoods along the roofline above the three new 

converters that will be exhausted directly to the smelter stack using 10 fans. 

a. 	 For each item identified in No.2 above, please include the estimated 

quantity of 802 that would be captured by said item. Please provide 

this estimate in terms of tons/year, as well as in terms of Ib/hr and 

maximum Ib/day. 

Asarco Response: 

Asarco did not separately consider partial building enclosure and tertiary ventilation, but 

looked at them as a combined system to improve emissions capture from converter 

fugitives that cannot be captured by the primary and secondary hooding systems. On 

an annual basis, the new tertiary hoods are expected to capture 240 tons/yr, or 95% of 

the S02 that would escape the new primary and secondary hoods. The maximum daily 

capture rate would be 2091 Ib/day, with a maximum hourly capture rate of 103 Ib/hr. 

For air permitting purposes, Asarco has estimated the amount of S02 that would be 

captured by the building enclosure and tertiary ventilation are as follows: 

• 	 Tons/year: 240 tons/yr ('from GCT) 

• 	 Max Ib/hr: 103 Ib/hr (from GCT) 
Response to EPA Information Request dated June 27,2013 

A8ARCO LLC-Hayden Operations 

July 11, 2013 

Page 7 

• 	 Design Ib/hr (97% secondary hood): 54.8 (240 tons/yr * 2000 Ibs/8760 hr) 

• 	 Max Ib/day (at 93%): 2091 Ibs/day (from GCT) 

b. 	 For each item identified in No.2 above, please include the estimated 

quantity of 502 that would be left uncaptured by said item. Please 

provide this,estimate in terms of tons/year, as well as in terms of 

maximum Ib/hr and maximum Ib/day. 

Asarco Response: 

Asarco did not separately consider building enclosure and tertiary ventilation, but looked 

at them as a combined system to improve emissions capture from converter fugitives 

that cannot be captured by the primary and secondary hooding systems. On an annual 

basis, the expected rate of 802emissions not captured by the new tertiary hoods would 

be 12 tons/yr, or 5% of the 802that would escape the new primary and secondary 

hoods. The maximum daily 802 emissions rate not captured by the tertiary hoods would 

be 105lb/day, with a maximum hourly 802 rate not captured by the tertiary hoods of 17 

Ib/hr. 

For air permitting purposes, Asarco has estimated the amount of 802 that would not be 

captured by the building enclosure and tertiary ventilation as follows: 

• 	 Tons/year: 12 tpy (from GCT) 

• 	 Max Ib/hr (93% secondary hood): 17 Ib/hr (from GCT) 

• 	 Design Ib/hr (97%): 1132.8 Ib/hr * (1-0.97) control * 0.05 not captured + 1040.3 

ton/yr secondary * (1-0.9 control) * 0.05 not captured * 2000 Ibs/8760 hr =2.9 

Ib/hr 

• 	 Max Ib/day: 105 Ib/day (from GCT) 

c. 	 For each item identified in No.2 above, please include the 

supporting calculations used to determine the quantity of 502 

captured by implementation of said item. If such calculations are 

available in an electronic format, such as a spreadsheet program like 

Excel, or process simulator output, provide the supporting 

calculation in said electronic format. 

Asarco Response: 

Asarco's revised spreadsheet page for 802 emissions for the pending CRP is attached. 

This provides the basic numbers used above. The 930/0 values were derived by 

substituting them in lieu of the 970/0 values shown. This was done by hand. Other 

values were provided by GCT. Calculations are shown in the answers above, where 

available. 
Response to EPA Information Request dated June 27,2013 

A8ARCO LLC-Hayden Operations 

JuIy 11, 2013 

Page 8 

As noted above, the CRP is a holistic solution for sulfur capture and fixation that is not 

easily split among its various components. For purposes of air permitting, Asarco has 

developed estimates. These estimates differ slightly from the design specifications set 

forth in the preceding paragraphs due to the interactions between the pieces of 

equipment and rounding differences. 

d. 	 For each item identified in No.2 above, please provide the purchased 

equipment cost, installation costs, and operating and maintenance 

costs associated with said control option. 

Asarco Response: 

The total installed (supply plus installation) cost for the CRP solution is $13,400,000. 

Annual operating and maintenance costs are expected to be approximately $300,000. 

3. 	 Please identify and describe any control options that ASARCO considered 

for controlling 502 emissions that are captured by items identified in No.2 

above. 

Asarco Response: 

For 802 control options for Item 2, A8ARCO has not considered any 802 control 

options for the new tertiary hoods due to the very low 802 concentration and emissions 

rate. 

a. 	 For each control option identified in No.3 above, please include an 

estimate of the control effectiveness of the option, as well as an 

estimate of the post-control 502 emission rate. Please provide these 

estimates on a long-term (annual) basis, as well as on a short..term 

basis (maximum 1-hr average and maximum daily emission rate). 

Asarco Response: 

Not applicable. 

b. 	 For each control option identified in No.3 above, please include the 

supporting calculations used to determine the post-control 502 

emission rate. Please provide this information in an electronic format 

that may be edited by a spreadsheet program such as Excel or 

comparable software. 

Asarco Response: 

Not applicable. 
Response to EPA Information Request dated June 27, 2013 

A8ARCO LLC-Hayden Operations 

July 11 , 2013 

Page 9 

c. 	 For each control option identified in No.3 above, please provide the 

purchased equipment cost, installation costs, and operating and 

maintenance costs associated with said control option. 

Asarco Response: 

Not applicable. 

4. 	 Identify and describe any control option that ASARCO, or an entity working 

on behalf of ASARCO, considered for controlling S02 emissions captured 

and vented to secondary converter hooding. 

Asarco Response: 

For 802 control options for controlling 802 emissions captured and vented in secondary 

converter hooding, the considered solution in the CRP is to send the secondary hood 

exhaust on the blowing converter to the existing acid plant for sulfur fixation as included 

in Item 1. 

a. 	 For each control option identified in No.4 above, please include an 

estimate of control effectiveness, as well as an estimate of the postcontrol S02 emission rate. Please provide these estimates on a long· 

term (annual) basis, as well as on a short-term basis (maximum 1·hr 

average and maximum daily emission rate). 

Asarco Response: 

The CRP solution is expected to control 84% of all 802captured by the converter 

secondary hoods, reducing the average 802emissions rate from the secondary 

baghouse from 5,748 to 936 tons/yr. The maximum daily emissions rate from the 

secondary bag house would be 5,000 Ib/day, and maximum hourly emissions rate would 

be 360 Ib/hr. 

b. 	 For each control option identified-in No.4 above, please include the 

supporting calculations used to determine the post-control S02 

emission rate. Please provide this information in an electronic 

format that may be edited by a spreadsheet program such as Excel 

or comparable software. 

Asarco Response: 

8ee attached spreadsheet. 
Response to EPA Information Request dated June 27, 2013 

ASARCO LLC-Hayden Operations 

July 11, 2013 

Page 10 

c. 	 For each control option identified in No.4 above, please provide the 

purchased equipment cost, installation costs, a.nd operating and 

maintenance costs associated with said control option. 

Asarco Response: 

The cost for implementing this solution is included in the Item 1 cost ($95,700,000) and 

cannot be done independent of the Item 1 solution. 

5. 	 Identify and describe any improvements or upgrades to the acid plant that 

A8ARCO, or an entity working on behalf of A8ARCO, considered for 

reducing 802 emissions from the acid plant. 

Asarco Response: 

For improvements to the acid plant, ASARCO has considered no modifications to 

reduce S02 emissions from the acid plant. As brief analysis is presented in the 

preliminary BART analysis presented below. 

a. 	 For each item identified in No.5 above, please include the estimated 

802 emission rate of the acid plant following implementation of said 

item. Please provide this estimate in terms of tons/year, as well as in 

terms of maximum Ib/hr and maximum Ib/day. 

Asarco Response: 

See preliminary BART analysis below. 

b. 	 For each item identified in No.5 above, please include the 

supporting calculations used to determine the estimated 802 

emission rate associated with implementation of said item. If such 

calculations are available in an electronic format, such as a 

spreadsheet program like Excel, or process simulator output, 

provide the supporting calculations in said electronic format. 

Asarco Response: 

See preliminary BART analysis below. 

c. 	 For each item identified in No.5 above, please provide the costs, if 

estimated, of purchasing, implementing, and operating said item. 

Asarco Response: 
Response to EPA Information Request dated June 27, 2013 

ASARCO LLC-Hayden Operations 

July 11, 2013 

Page 11 

See preliminary BART analysis below. 

6. 	 For each unit comprising the BART-eligible source that was included in 

model runs used to determine ambient S02 impacts, please list the source 

parameters that characterized the unit in the model runs, including: 

a. Source location in either UTM coordinates or latitude and longitude. 

Please specify the datum. 

b. Base elevation. 

c. For point or pseudopoint sources, include the stack height, stack 

diameter, exhaust temperature, and exit velocity. 

d. For area sources, include the initial vertical dimension, or the initial 

depth, of the area source plume, the release height above ground, 

and the dimensions of the area source (either x-side and y-side for 

polygons, or radius for circular). 

e. For volume sources, include the initial lateral dimension, initial 

vertical dimension, and release height. 

f. In instances where multiple versions of source parameters may have 

been used to characterize a unit, include all versions of the source 

parameters. 

Asarco Response: 

Asarco treated all emissions from the converter aisle (converters #1-#5) and anode 

furnaces (#0-#2) as being emitted from the BART-eligible units (converters #1, #3-#5 

and anode furnaces #1 and #2) because not all converters or anode furnaces can 

operate at a single time, yet it is conceivable that only BART-eligible units could be 

operating at a single time (although even then it is unlikely that four converters would be 

in operation). With this understanding, Asarco relied upon the original WRAP modeling 

work (to verify archived model accuracy) and then used revised values. 

The original WRAP model inputs are enclosed as Attachment 6-1. Note that the X and 

Y coordinates are given in Lambert Conformal Conic (LCC-X) km and Lambert 

Conformal Conic (LCC-Y) km respectively. Based on the best information available to 

Asarco, the LCC-X and LCC-Y were derived from UTM 12 NAD 83 coordinate system. 

It appears that ENVIRON (the WRAP modeler) converted the emissions points listed as 

"Fugitive" to equivalent circular diameters of approximately the same size shown in the 

revised Asarco model inputs. 

The revised Asarco model inputs are enclosed as Attachment 6-2. 

ASARCO Preliminary S02 BART Analysis 

A. Process Description 
Response to EPA Information Request dated June 27,2013 

ASARCO LLC-Hayden Operations 

July 11, 2013 

Page 12 

Production of copper from sulfide ores, typically containing less than 1% copper, 

requires beneficiation of the ore through crushing, grinding and froth flotation. Such 

separation process liberates copper-bearing minerals from the host rock and yields a 

mineral-enriched material that typically contains 20 to 30 percent copper, commonly 

referred to as "concentrate". The concentrate must be further processed by smelting to 

produce usable copper. 

The Hayden copper smelting process includes 3 steps: smelting concentrate in the 

INCO Flash Furnace to produce molten matte, converting matte to blister copper, and 

fire refining blister copper to produce anodes for electrolytic refining. Concentrate is 

combined in the bedding plant with siliceous flux and recycled process materials, and 

the resultant furnace feed is dried in the fluid-bed dryers. The dried feed is introduced, 

along with combustion oxygen, into an INCO oxygen flash furnace where iron and sulfur 

in the feed combust, or "flash" in the high-temperature, oxygen-rich furnace 

atmosphere. The resultant molten material collects at the bottom of the furnace as a 

"bath" where it naturally separates into two layers, matte and slag. This smelting 

process eliminates approximately 60 percent of the iron and sulfur in the concentrate. 

Iron oxidizes and combines with silica flux to form a molten slag, and sulfur oxidizes to 

sulfur dioxide gas (S02), which is sent through a gas cleaning system and then to the 

acid plant to be made into sulfuric acid. The copper-rich layer, matte, is tapped from the 

furnace and directed via ventilated launders into ladles that are staged below the 

furnace floor. Matte typic~lIy contains 45 to 65 percent copper. Once the ladles are 

filled, they are moved into the converter aisle for crane transfer to the converters. The 

slag is skimmed into a slag pot for movement to the slag cooling or deposition area. 

The Hayden Smelter utilizes five Peirce-Smith furnaces to convert matte to blister 

copper. Overhead cranes transfer the matte-filled ladles from the flash furnace to the 

converters. Converting consists of blowing air or oxygen-enriched air through the 

molten bath and adding siliceous flux and other copper-bearing materials at various 

times during the process to control bath temperature and to facilitate the chemical 

reactions that allow the formation of an iron/silica slag. A typical cycle converts ten 

ladles of matte to four ladles of blister copper (980/0 to 99% pure copper). 

Each converter at the Hayden smelter is equipped with primary and secondary hooding 

systems. The primary hooding system is designed to capture the S02-containing gases 

that are evolved while the converters are blowing or "rolled-in". These gases are routed 

through a gas cleaning system to remove particulate matter before reporting to the acid 

plant for conversion to sulfuric acid. The acid plant tail gas reports to the center of the 

facility's 1,OOO-foot stack. The secondary hooding system is designed to capture 

fugitive gases and particulates that escape the primary hoods or are emitted when the 

converter is "rolled-out" for skimming and charging. Gases that are collected by the 

secondary hoods are directed to a baghouse for particulate matter removal before being 

exhausted to the atmosphere via the annulus of the facility's 1 ,OOO-foot stack. 
Response to EPA Information Request dated June 27,2013 

ASARCO LLC-Hayden Operations 

July 11,2013 

Page 13 

B. BART-ELIGIBLE UNITS ANALYSIS 

Based on EPA's Guidelines for BART Determinations Under the Regional Haze Rule, 1 

ASARCO LLC ("Asarco") has reviewed the Hayden Smelter's individual primary 

smelting units to determine whether they are BART-eligible consistent with the Act's and 

the Guidelines' requirements. Under the Act and Guidelines, once a source is 

determined to be BART-eligible, the start-up dates of each BART emission unit must be 

identified.2 In general, a unit that was "in existence" on August 7, 1977, but not "in 

operation" before August 7, 1962, is a BART-eligible unit. 

The best general reference for the construction dates of the potentially BART-eligible 

equipment at the Hayden Smelter is Attachment "C" to Asarco's Title V Operating 

Permit No. 1000042. This permit lists the following equipment and dates: 

Unit I nstallation Date BART-eligible? 

2 x Concentrate Dryers 1983 No, post 1977 

1 x Inco Flash Furnace 1983 No, post 1977 

5 x Converters Various See below 

2 x Anode Furnaces (#1 and #2) 1971 Yes 

1 x Anode Furnace (#0) 2001 No, post 1977 

Acid Plant 1983 No, post 1977 

The concentrate dryers, INCO flash furnace and acid plant were installed as part of a 

single modernization effort that occurred after the BART applicability date and were, 

accordingly, not "in existence" on August 7, 1977 as that term is defined in the BART 

regulations and Guidelines. 3 

Asarco agrees that anode furnaces #1 and #2 were installed in 1971, operating no later 

than 1973, and are BART-eligible units.4 Anode furnace #0 was installed in 2001 and is 

not BART-eligible because it was not "in existence" during the BART-eligibility period.s 

The converters present a more complex picture. Based on a historical narrative 

authored by E. S. Godsey, Asarco commenced operation of the Hayden Smelter in 

1912 with two converters, and operated with three converters of various sizes and 

configurations between the years of 1913 and 1966. Recent research of engineering 

and purchasing records indicates that one of the existing converters, #2, pre-dates the 

140 C.F.R. Part 51, App. Y [hereinafter Guidelines]. Asarco notes that the Guidelines are guidelines only and that 


the State retains discretion to weigh the five BART factors as it sees fit. Guidelines, § I.F.l. 


2 Guidelines, § II.A.2. 


3 Permit 1000042, Attachment "C"; see also Guidelines, § II.A.2. 


4 Permit 1000042, Attachment "C".. 


s Permit 1000042, Attachment "C"; see also Guidelines, § II.A.2. 

Response to EPA Informa~ion Request dated June 27,2013 

ASARCO LLC-Hayden Operations 

July 11, 2013 

Page 14 

The converters present a more complex picture. Based on a historical narrative 

authored by E. S. Godsey, Asarco commenced operation of the Hayden Smelter in 

1912 with two converters, and operated with three converters of various sizes and 

configurations between the years of 1913 and 1966. Recent research of engineering 

and purchasing records indicates that one of the existing converters, #2, pre-dates the 

BART-eligibility period, and that one converter was added and three converters were 

replaced with larger units during the BART-eligibility period. At this time, Asarco 

believes that the following units are BART-eligible: 

• 	 Converter #1 - Installed in 1966. BART-eligible. 

• 	 Converter #2 - Purchased and installed in 1949/50 and still operating. Not BARTeligible. 

• 	 Converter #3 - Replaced a 10'x26' unit with a 13'x33' unit in 1965. BARTeligible. 

• 	 Converter #4 - Replaced a 13'x30' unit with a 13'x33' unit in 1966. BARTeligible. 

• 	 Converter #5 - Replaced a 13'x30' unit with a 13'x35' unit in 1975. BART­


eligible. 


A copy of the purchase order for converter #2 is attached. Accordingly, anode furnace 

#1, anode furnace #2, converter #1, converter #3, converter #4 and converter #5 are the 

only BART-eligible units. 

C. SUBJECT TO BART ANALYSIS 

Asarco acknowledges that ADEQ and the Western Regional Air Partnership (WRAP) 

modeled the Hayden Smelter during development of the Section 308 Regional Haze 

State Implementation Plan (SIP). Based on that modeling, the Hayden Smelter was 

shown to be "subject to BART" because it caused a visibility impact of greater than 0.5 

dv at the most affected Class I area. While Asarco believes that the WRAP modeling 

effort used inappropriate potential to emit, rather than "steady-state operating conditions 

during periods of high capacity utilization" as recommended by the Guidelines] 6 Asarco 

concedes that the Hayden Smelter's converters #1, #3, #4, #5 and anode furnaces #1 

and #2 are subject to BART for S02. NOx and PM BART were previously addressed in 

prior State and EPA actions. 

D. S02 BART ANALYSIS 

Step 1: Identify the Existing Control Technologies in Use at the Source 

According to Air Quality Permit 1000042, issued by ADEQ on October 9, 2001, the 

Asarco Hayden smelter has installed and operates the following control technologies on 

6 Guidelines, § IILA.3, Option 1 (2). 
Response to EPA Information Request dated June 27,2013 

ASARCO LLC-Hayden Operations 

July 11, 2013 

Page 15 

the equipment subject-to-BART: 

Converters #1-#5 

Primary Hoods routed to Acid Plant 

Secondary Hoods routed to Secondary Hood Baghouse 

Anode Furnaces #1-#2 

No controls 

Substantial upgrades to the air pollution control equipment for the BART-eligible units 

have been installed since August 1977. According to ADEQ's Final Hayden Sulfur 

Dioxide Nonattainment Area State Implementation and Maintenance Plan, dated June 

2002, prior to 1971, all smelting operations process gasses from the facility were 

emitted into the atmosphere after electrostatic precipitators removed the particulate 

matter from the gases. In 1971, however, the company installed an acid plant as an 

S02 control for primary converter gases. According to sulfur balance information from 

the time period, S02 en1issions from the facility were well in excess of 100,000 tons per 

year. 

In 1983, the company undertook a series of additional improvements, including the 

replacement of twelve multiple-hearth roasters and two reverberatory furnaces, 

replacing them with an INCO Flash smelting furnace. At the same time, Asarco installed 

a 650 ton per day oxygen plant that would enrich the smelting process gasses. Based 

upon this addition, the company was able to replace the existing single contact acid 

plant with a new double-contact acid plant. The emissions reductions resulting from 

these projects were estimated to be 63,584 tons per year of S02. According to 

ASARCO's calculations, the double-absorption acid plant recovers 99.81 percent of the 

S02 emissions that are vented to it. 

In 1998, ASARCO made a modification to the smelter's existing gas handling system, 

and installed an $18.4 million wet gas handling system. This modification allowed the 

flash furnace off gas to be treated at temperatures that are less than 2000 F, 

approximately 4000 F less than the previous system. Due to the lower temperatures, 

the volume of gas being vented from the flash furnace was reduced, enabling the acid 

plant to provide additional ventilation to the converters. This additional ventilation 

allowed the secondary hoods to capture more S02 emissions from the converter 

building. 

Steps 2-3: (2) Identify all available retrofit control technologies with practical 

potential for application to the specific emission unit for the regulated 

pollutant under consideration; and (3) eliminate all technically infeasible 

control technologies. 

In the Section 308 Regional Haze SIP, ADEQ determined that the Kennecott Utah 
Response to EPA Information Request dated June 27,2013 

ASARCO LLC-Hayden Operations 

July 11, 2013 

Page 16 

Copper Corporation's continuous production of blister copper is a fundamentally 

different process from the process employed by Asarco's Hayden Smelter. ADEQ has 

also determined that BART does not contain a requirement that the source be 

redesigned when the Agency considers the available control alternatives. As a result, 

ADEQ concluded that it is not necessary to consider the use of Kennecott Utah Copper 

Corporation's process as a potential BART alternative. Section 308 SIP, § XII.C, at 88. 

EPA concurred with this determination. 77 Fed. Reg. 75704, 75726 (Dec. 21, 2012). 

Asarco also concurs. 

Evaluation ofpossible control technologies. The following technologies are 

potentially available for S02 control from the Converters and Anode Furnaces: 

Double contact acid plant (existing) 

Wet scrubbing 

Dry scrubbing 

According to ADEQ's Final Hayden Sulfur Dioxide Nonattainment Area State 

Implementation and Maintenance Plan, dated June 2002, the process changes and 

installation of air pollution controls through the years has resulted in an increased 

overall S02 control efficiency at the Hayden primary copper smelter. Since the 1970s, 

the S02 control rate has risen from approximately 32%) to approximately 42% with the 

installation of the double contact acid plant in the mid-1980s, to approximately 92%) as a 

result of the wet gas handling system and related improvements. Conversely, estimated 

S02 emissions from the facility fell from approximately 200,000 tons per year in the 

early 1970s, to less than 25,000 tons per year at the current time. 

Asarco will consider the possible applicability of adding scrubbing to the Acid Plant tail 

gas, the Secondary Hood Baghouse exhaust, and tertiary ventilation gases in this 

preliminary BART analysis. 

Technical feasibility. All of the technologies identified above were judged to be 

potentially feasible of application to the Converter primary gas stream, except for dry 

scrubbing. There is no known application of dry scrubbing downstream of an acid plant 

and the wet, acidic atmosphere would render a bag house (used to collect the dry 

scrubbing sorbent) ineffective. Dry scrubbing is thus deemed technically infeasible for 

installation post-acid plant. In addition, dry scrubbing is deemed technically infeasible 

for application as a supplementary control for the existing Secondary Hood Baghouse 

because of the conversion of reagents to gypsum and subsequent interference with 

resmelting baghouse dusts. 

Acid plants are not technically feasible for the Converter secondary gas stream, the 

Anode Furnaces, or a tertiary ventilation system due to the low concentration of S02 

present (estimated to be well below 1% ). 
Response to EPA Information Request dated June 27, 2013 

ASARCO LLC-Hayden Operations 

July 11, 2013 

Page 17 

Wet scrubbing and dry scrubbing are judged techniC(ally infeasible for tertiary ventilation 

of the Converters or for the Anode Furnaces because the concentration is too low «20 

ppm S02) for effective scrubbing. 

Step 4. Ranking of Control Effectiveness. 

Asarco's technical experts were not able to identify any control technology that would 

result in more substantial S02 emission reductions than the present double absorption, 

double contact acid plant. While Asarco has identified a change in converter technology 

that could result in decreased S02 emissions-replacement of the current five variablysized converters with three identically-sized converters to allow more balanced 

operation-wholesale replacement of the process source is inconsistent with "best 

available retrofit technology," which unambiguously allows only control technology that 

"retrofits" existing process equipment, not replacing existing process equipment. 

Similarly, changing the Hayden smelter from a five converter operation to a three 

converter operation constitutes a redesign of the source. Redesign is not required. 7 

Because the double contact acid plant is the best available technology and it is already 

applied, no further consideration of wet scrubbing or dry scrubbing, which cannot 

achieve equivalent results, is required.s 

The remaining technologies under consideration are: 

Primary Off-gas: 	 Double Contact Acid Plant, 98.8% control (already in place) 

Tail gas wet S02 scrubbing (supplemental control), 90% 

Secondary Off-gas: 	Wet S02 scrubbing, 85% control 

Steps 5-7. (5) Evaluate energy and non-air quality environmental impacts; (6) 

Evaluate visibility impacts; and (7) select BART. 

In these steps, Asarco evaluates energy, non-air quality environmental impacts, cost, 

and visibility impacts and based upon that analysis, recommends BART. 

Primary Off-gas. Asarco already has in place the most effective technology, a doublecontact acid plant. In the proposed rule to approve in part and disapprove in part the 

Arizona Regional Haze SIP, EPA questioned whether the Hayden Acid Plant was 

operating at optimum levels and questioned whether control levels at other industry acid 

plants might achieve higher levels. Finally, EPA questioned whether ADEQ's 

application of NSPS Subpart P adequately addressed all gases putatively controlled by 

Subpart P. Asarco responded to those questions in its comments. See Asarco 

7 40 C.F.R. Part 51, App. 7, § IV.D.l(5). 

8 Guidelines, § IV.D.I (9) 
Response to EPA Information Request dated June 27, 2013 

ASARCO LLC-Hayden Operations 

July 11, 2013 

Page 18 

comments, dated March 6, 2013, a copy of which is included in Attachment BART-1 and 

which is hereby incorporated into this analysis. 

In its analysis, Asarco det~rmined that the double contact acid plant remains the best 

control technology for control of strong acid gas streams; that other types of acid plants 

do not provide meaningful guidance on what Asarco should be able to achieve based 

on differences in the nature of the various processes, inputs, and operating variabilities 

(as EPA also determined in the Background Information Document for NSPS Subpart 

P), and that the NSPS Subpart P limit of 650 ppm. represents the best limit that is 

consistently achievable given natural process variability and degradation of catalysts 

over time. Because Asarco believes that the uncontroverted record is clear that a 

double contact acid plant is the best control for a strong gas stream, further analysis is 

not required. Asarco will continue to maintain and operate is double contact acid plant 

consistent with the enforceable limits and monitoring conditions of NSPS Subpart P, 

which it hereby recommends be adopted as BART. 

Asarco did consider the possibility of adding a tail gas scrubber to the acid plant. The 

estimated cost of such a unit is approximately $13 million. In addition, an annual 

$350,000 in operating expense is anticipated. Based upon these expenses, which 

amount to an annualized cost of $1,000,000, and assuming that the wet scrubbing 

achieved 90% control of the 507 tons emitted from the Acid Plant9 (only roughly 

240/1060 of this S02, or 114.8 tons is attributable to BART-eligible units), 10 the cost 

exceeds $9500/ton for the 103 tons removed. Wet scrubbing would require 

approximately 75 gallons/minute of water, amounting to roughly 121 acre-feet/annum, a 

considerable expenditure of water in an arid environment. Similarly, wet scrubbing 

would generate large volumes of wastewater and sludge, requiring substantial 

additional expense to manage and treat. 

Asarco did not evaluate the cost in $/dv given the high cost on a $/ton basis. 

Based on all of these considerations, Asarco believes that the Acid Plant represents 

BART for the primary off-gas stream because it represents the best current technology 

and that add-on technologies do not achieve substantial visibility improvements, yet 

represent a substantial increase in operating cost, consume valuable landfill space, and, 

for wet scrubbing, large qU,antities of precious water in an arid environment. Asarco 

finds that the costs and landfill capacity consumption outweigh the small visibility gain. 

BART is therefore selected as no further control beyond the existing double 

contact acid plant at NSPS Subpart P limits of 650 ppm. Additionally, Asarco 

recommends that the NSPS Subpart P continuous emissions monitoring, 

recordkeeping and reporting provisions be adopted to ensure adequate 

enforceability. 

92002 Emissions from 2002 Emissions Inventory. Highest during 3 year period 2001-2003, 

10 AP-42, Chapter 12.3, Table 12.3-3 
Response to EPA Information Request dated June 27, 2013 

ASARCO LLC-Hayden Operations 

July 11, 2013 

Page 19 

$28 million, exclusive of th~ cost of a booster fan and possibly a new or modified stack 

to handle wet discharge gas. In addition, an annual $8-9 million in operating expense is 

anticipated. Based upon these expenses, which amount to an annualized cost of $9.4 

million (assuming only $8 million in annual cost), and assuming that the wet scrubbing 

achieved 85% control of the 16,391 tons emitted from the Secondary Hood Baghouse,11 

or 13, 932 tons/year, the cost exceeds $675/ton. Wet scrubbing would require 

approximately 75 gallons/minute of water, amounting to roughly 121 acre-feet/annum. 

Wet scrubbing would generate large volumes of wastewater and sludge, requiring 

substantial additional expense to manage and treat. Further, because Asarco currently 

recycles these dusts to the process, either additional cost to dry the material and return 

it to the process or to dispose of the material, including lost copper recovery, would 

need to be added to the cost of control. 

Alternatively, Asarco is working on the CRP. The CRP would reduce emissions to the 

Secondary Hood Baghouse to 936.2 tons (potential to emit) versus 2,459 tons/year 

(projected actual) emissions from the wet scrubbing alternative. The CRP is able to 

achieve additional reductions by balancing converter gas generation better with flash 

furnace gas generation and fully utilizing existing Acid Plant capacity. The CRP 

constitutes a "beyond BART" control because it requires a change in plant con'figuration 

(replacement of the five existing converters with three new, slightly larger converters to 

allow the balancing described above). 

Asarco did not conduct modeling of the visibility impact in light of the higher emissions 

reductions anticipated from the proposed CRP. 

In light of the proposed CRP, which would eliminate the need for the wet scrubbing, and 

after considering the adverse energy, water and sludge impacts caused by 

implementing a wet scrubbing system, Asarco believes that the existing Acid Plant 

represents BART for the primary and secondary off-gas streams because it represents 

the best current technology and that add-on technologies do not achieve substantial 

visibility improvements, yet represent a substantial increase in operating cost, consume 

valuable landfill space, anq, for wet scrubbing, large quantities of precious water in an 

arid environment. Asarco 'finds that the costs and landfill capacity consumption 

outweigh the likely visibility gain. BART is therefore selected as no further control 

beyond the existing double contact acid plant at NSPS Subpart P limits of 650 

ppm. Additionally, Asarco recommends that the NSPS Subpart P continuous 

emissions monitoring, recordkeeping and reporting provisions be adopted to 

ensure adequate enforceability. 

Tertiary Ventilation. Given the absence of any technically feasible S02 controls, 

BART is determined to be no additional control. 

112002 Emissions from 2002 Emissions Inventory. Highest during 3 year period 2001-2003. 
Response to EPA Informa·tion Request dated June 27, 2013 

ASARCO LLC-Hayden Operations 

July 11, 2013 

Page 20 

Anode Furnaces. A review of EPA's RACT/BACT/LAER Clearinghouse (RBLC) 

revealed that there are no air pollution control devices that have been approved for 

anode furnace operations. Other S02 controls are not feasible given the low 

concentration of S02 is the gas stream. Given the absence of any technically 

feasible 502 controls, BART is determined to be no additional control. 

Asarco appreciates the opportunity to provide this explanation of its plans and analyses 

for the Hayden Smelter to EPA. Based upon the best available information, the 

proposed CRP is the best, if not the only, effective alternative for S02 emission control 

from the Hayden Smelter. Adoption of the CRP will achieve superior results to those 

that can be achieved through the BART process. Given that Asarco wishes to proceed 

with the CRP as expeditiously as possible, Asarco does not believe that a BART 

determination is necessary or appropriate. 

Please contact me at 520-356-3284 if you have any questions concerning this 

response. 

Sincerely, "­

/ . ./ ~?CNVL t: j

Jack Garrity 

Technical Services Manager 

JG/rcg 

Attachment - CD 

REnviro/AIRlHayOps/Smelter/OtherCorres/BART/EPARFI6.27.13/AsarcoResponsetoEPAJuneRFI7.11.13