Best Practices for Dust Control in 

Metal/Nonmetal Underground Mining 

Greg Chekan 

Mining Engineer 

NIOSH 
Overview 

• Case studies of dust control in largeopening mines: 

– Dump/crusher 

– Production shots 

– Haulage cycle 

– Other sources 
Dust Control in 

Large-opening Mines 

Ventilation 

–Dilute and transport dust from 

mine atmosphere 

–Direct dust away from workers 

 
 

 

 

 

 

 

 

Improvements in Venti

 

lation to Remove 

Harmful Particulate 

Mine-wide – Main fan to 

establish airflow on a 

mine-wide basis 

Local – Booster fans 

for more direct and 

controlled air volume 
Improvements in Ventilation to 

Remove Harmful Particulate 

 

Stoppings – in key 

locations to more 

efficiently direct and 

control airflow 

Long Pillars – reduce 

number of stoppings 
Controlling Dust with Ventilation 

 Dump/Crushing Facility – Local Ventilation 
UNDERGROUND CRUSHERS 

• As mines become 

larger, crusher 

facilities are located 

underground 

• Major point source of 

silica dust requiring 

engineering controls 
Isolate crusher 

from general mine 

air using curtain 

stoppings. 

Use booster fans 

to transport and 

dilute dust. 
Evaluated Two Types of Fans 

Axial Vane Fan 

• 36-inch diameter 

• 50 hp electric 

• 50,000 cfm 

Propeller Fan 

• 60-inch diameter 

• 27.2 hp diesel engine 

• 50,000 cfm 
Main Air 

Return 

Axial Vane or 

Propeller Fan 

 Location of Crusher, 

15 Stoppings, 

and Fans 
Sampling Strategy 

Characterize dust levels 

and distribution around 

the crusher by area 

sampling at six key 

locations 

Sample for three days for 

each fan 

Fan approximately 

100 ft from dump 
Area Sampling 

1- Intake/crusher side 

2 - Dump 

3- Crusher: outside/inside booth 

4- Belt 

5- Return/crusher side 

6- Adjacent entry 

 
Pressurization and Dust Filtration System 

Operator’s Booth

Crusher: 300 hp – 1,000 tph 
Daily Production Per 

Sampling Shift 

Axial Vane Fan Propeller Fan

Shift 

number

1 2 3 1 2 3

Gravimetric 

sampling 

time, min

316 322 298 325 312 297

Measured 

tonnage

3780 3890 3890 3820 3785 3820

 

 
Velocity Measurements 
Axial 

Fan type Vane Propeller

Average air velocity at 

regulator, fpm 690 725

Average Air Velocity Across Dump, fpm 

Left Side Center Right Side 

Avial Vane 240 0 0 

Propeller 240 140 100
Results: 

Gravimetric Samplers 
Respirable Dust Concentrations 

 Gravimetric Sampling: 3-Day Average 
Respirable Silica Dust Concentrations 

 Gravimetric Sampling: 3-Day Average 
Propeller Fan 

vs.

Axial Vane Fan 

Reductions in Dust

3-Day Average

Respirable Dust 

Averaged 16% Reduction 

Respirable Silica 

 Averaged 21% Reduction 
Best Practices 

1. Isolate the dump/crusher/belt from the general mine 

air 

2. Provide ventilation to move dust to return air 

3. Locate booster fans as close to the dump as possible 

for better air movement 

To protect operator 

 

Equip booth with a filtration/pressurization system 
Controlling Dust with Ventilation 

 Production Shots: Mine-wide Ventilation 
Dust Generated by Production Shots 

• Can generate high 

quantities of dust 

depending on number of 

shots 

• Inadequate ventilation 

may cause dust clouds to 

break up and disperse in 

mine 

• Leads to higher 

background levels of 

silica that can recirculate 

in mine atmosphere 
Thermo Scientific’s personalDataRam (pDR) 

• pDR gives the time and 

average concentration 

over logged period 

• The movement of shot 

dust through the mine 

can be monitored and 

evaluated using pDRs 
 Point Source of Dust 

Dust Cloud Signature 

Logged time, known distance, estimate velocity 
Typical Results of Dilution of 

Respirable Dust from Shot Source 

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

400 700 900 1100 1500

Distance from Shot, ft

Concentration, mg/m

3

Concentrations from 

pDR Sampling 
Case Study 

Determine influence of fan and curtain 

installation for improving both ventilation 

and shot dust removal from mine 
Improving 

Mine-wide 

Ventilation

 

 

 

Curtain Stoppings

Propeller Fans 
Objectives 

• Monitor travel path of the dust cloud 

 

• Determine average air velocity based on 

time-to-station dust data 

• Establish the in-mine dust retention time 

– Time required to clear dust from the mine 
Dust 

Sampling 

Position pDRs 

around curtain

perimeter to 

monitor dust 
Initial Test Condition 
Estimated Air Velocities 
Two Hartzell 

high volume/low 

pressure propeller 

fans each rated at 

500,000 cfm

Over 40 curtain 

stoppings around 

perimeter of faces 
Final Test Condition 
Estimated Velocities After Installation of 

Propeller Fans and Curtain Line 
Propeller Fan and Curtain Line 

Air Velocity Enhancement 

 

 Full Curtain 

 Partial Curtain 
Dust Retention Time 

 

120 min 

No Propeller Fans and Partial Curtain Line 

 

20 min 

Propeller Fans and Completed Curtain Line 
Best Practices 

• Install a main fan to establish air circuits on a 

 mine-wide scale 

• Install permanent or brattice stoppings or 

long pillars in key locations throughout the 

mine to more efficiently direct and control 

airflow 

• Use booster fans to assist main fan if needed 
UNDERGROUND GOLD MINE 

SAMPLING TRUCKS 

DURING THE 

HAULAGE CYCLE 
OBJECTIVE: 

BASELINE STUDY 

• Evaluate truck 

driver dust 

exposure 

during haulag

cycle 

• Determine the 

difference in 

silica dust 

levels between

dry and wet 

stopes 

e 
SAMPLING STRATEGY 

• Use gravimetrics 

and pDRs 

• Use pDRs to monitor 

trucks during 

haulage cycle 
SAMPLING STRATEGY 

• Record load, tram, 

and dump times 

• Record tonnage 

• Collect area 

samples at other 

locations in stope 
Booster 

fans 

Dry Stope 

Wet stope 

Long-hole Open Stope
Intake air: 

560 fpm 

180,000 cfm 

Intake air 

supplemented 

by booster 

fans 

Axial vane fan: 

30,000 cfm 
Loading 

Samplers Truck 

Samplers 
Results from 

Gravimetric 

Samplers 
Respirable Dust 

• Intake low 

indicating clean 

air 

• Trucks 1 and 2 

very similar for 

three days 

• Load and dump 

locations were 

highest 

• Day 3: Wet 

muck, high 

concentration at 

some locations 

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

INTAKE TRUCK 1 TRUCK 2 LOAD DUMP RETURN

Concentration, mg/m3

Day 1 -Dry

Day 2 - Dry

Day 3 - Wet
Respirable Quartz Dust

• Trucks 1 and 2 

similar; little 

decrease on 

day 3 

• Quartz 

concentrations 

highest at 

dump 

• No consistent 

pattern 

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

TRUCK 1 TRUCK 2 LOAD DUMP

Concentration, mg/m3

Day 1 -Dry

Day 2 - Dry

Day 3 - Wet
Tonnage Per Sampling Period 

Tonnage loaded

on day 3 was 

almost twice 

the tonnage on 

days 1 and 2 

Day 

Trucks 1 and 2 

Combined 

Tons 

1 - Dry 330

2 - Dry 198

3 - Wet 528
Dry Versus Wet Muck – Respirable Quartz, mg 

• Quartz weight, 

(mg) vs. 

tonnage 

• Trucks 1 and 2:

40% more 

tonnage on 

day 3 

• Wet stope 

produced 28% 

less quartz by 

weight on filter 

0

0.005

0.01

0.015

0.02

0.025

0.03

0

100

200

300

400

500

600

DAY 1 (Dry) DAY 2 (Dry) DAY 3 (Wet)

Quartz, mg

Total Tons Loaded - Trucks 1 and 2 Combined

Average Quartz Weight on Filter, mg - Trucks 1 and 2 Combined

dedaoL snoT
Respirable Quartz 

• Quartz generation mg per 1,000 Tons 

normalized to 

1,000 tons 

• Wet muck: lower 

values at all 

locations 

• Percent Decrease: 

 Truck 1 – 170% 

 Truck 2 – 200% 

 Load – 30% 

 Dump – 280% 

 

0.00

0.05

0.10

0.15

0.20

0.25

0.30

Truck 1 Truck 2 Load Dump 

Quartz, mg/1000 Tons

DAY 1 (Dry)

DAY 2 (Dry)

DAY 3 (Wet)
HAULAGE CYCLE

 1) Loading 

 2) Tramming full 

 3) Dumping 

 4) Tramming empty 

Results from pDR 
Time Study Using pDRs 

• Truck 1 and 2 Dry vs. Wet Stope 

combined 

• Wet stope –

lower dust at 

loading, 

tramming 

 full and 

dumping 

• Trucks 1 and 2 

 32% and 35% 

reduction in 

dust levels, 

respectively 
Time-weighted-average Dust 

Contributions 

Dump location had highest dust contribution despite having 

the shortest duration... (14% time vs. 34% dust) 

(6.7 mins) 

(3.7 mins) 

(11.4 mins) (4.2 mins) 
Best Practices 

To reduce quartz levels: 

• Establish an air circuit with main mine fan 

• Use auxiliary air keeping it as close to the loading 

area as possible 

• Keep muck wet when loading 

• Control haul road dust 

 
Other Dust Sources 

• Scalers 

• Haul road dust 

• Down-hole drills 
Pick type 

harder rock 

Rotary head 

softer rock 
Cutting head 

Floor

Dust 

Sources 
Dust 

Issues

• Visibility 

• Nuisance dust 

>10 microns
Spray 

Systems 

• Spray 

systems 

Sprays must be 

located as close to dust 

source as possible 
500 Gallon 

Tank 

Refill 

2.5 hrs 
Move and dilute 

dust with booster 

fan 

Fan placement: 

Location of face 
Other Dust Sources 

• Scalers 

• Haul Road Dust 

• Down-hole drills 
Haul 

Road Dust Enclosed 

Cab 

...can be a significant source of dust liberation 
Safety Hazards: 

Impair operator’s visibility
Summer

High humidity 

Winter 

Road wetting 

to control dust 

generation 
ROAD WETTING EFFECT

Sampling with pDR 

 

Road Drying Out 

Wet road 
Haul Road Dust Research 

• 80% of dust is not 

respirable, > 10 

microns 

• Dust levels 

diminish 

approximately 50 

feet from source 

• Sampling shows 

that road wetting 

is an effective 

technique when 

practiced as 

required 
Best Practices 

• Road wetting is effective, but continual 

maintenance must be practiced

• Use traffic control as a dust control technique: 

– Max exposure occurs within 4–15 seconds behind a 

haul truck 

– Require trucks to maintain more than 20 seconds of 

separation 

– May result in a 40%–50% reduction in respirable dust 

exposure to the following truck 
Other Dust Sources 

• Scalers 

• Haul road dust 

• Down-hole drills 
Down-hole Drills 

 Ninety percent of 

dust emissions from:

• Drill shroud leakage 

• Drill stem bushing 

leakage 

• Dust collector dump 

discharge 
To Reduce Dust Exposure 

Use booster fans to 

remove dust in poorly 

ventilated benches 
Best Practices 

• Maintain a tight drill deck shroud enclosure with 

the ground 

• Maintain a collector-to-bailing airflow ratio of at 

least 3:1 

• Maintain the dust collector as specified by the 

manufacturer 
Disclaimer 

The findings and conclusions in this presentation are those 

of the authors and do not necessarily represent the views 

of NIOSH. Mention of any company or product does not 

constitute endorsement by the National Institute for 

Occupational Safety and Health (NIOSH). In addition, 

citations to Web sites external to NIOSH do not constitute 

NIOSH endorsement of the sponsoring organizations or 

their programs or products. Furthermore, NIOSH is not 

responsible for the content of these Web sites. All Web 

addresses referenced in this presentation were accessible 

as of the date the presentation was originally delivered. 
Thank You 

Greg Chekan 

E-mail: gcc8@cdc.gov

412-386-6676

Questions?