Dust Sampling 

Instrumentation 

and Methods 

Jay Colinet 

Office of Mine Safety and Health Research 

Senior Scientist 

National Institute for Occupational Safety and 

Health (NIOSH) 

Silica Dust Control Workshop 

Elko, Nevada 

September 28, 2010 
Presentation Outline 

• Current respirable dust standards and sampling 

requirements 

• Dust sampling instruments available for use in 

mining 

• Sampling methods to quantify dust sources 
Dust Standards for Metal/Nonmetal Mining 

(Federal Mine Safety and Health Act of 1977) 

10.0 mg/m3 total airborne dust 

If silica > 1%:

respirable standard = 10 / (% silica + 2)
Gravimetric Dust Sampler 

• Provides time-weighted-average respirable dust concentration 

• Dorr-Oliver cyclone separates respirable and oversize dust 

• Pump operated at 1.7 liters per minute in M/NM mines 
Sampling with Gravimetric Samplers 

• Filter is pre- and post-weighed to 

determine mass gain and is used to 

calculate an average dust 

concentration over sampling period 

• Filter processed using XRD analytical 

technique for silica content (NIOSH 

Method 7500) 

• Sufficient mass must be collected to 

have confidence in measurement 

• NIOSH typically uses multiple 

gravimetric samplers and averages 

data 
personalDataRAM (pDR) 

• Model 1000 AN passive sampler 

• Uses light scattering as 

measurement technology 

• Instantaneous readings 

correlated with time and stored in 

internal memory 

• pDR concentrations impacted by: 

– size distribution of dust 

– composition of dust 

– water mist in air 

• OMSHR adjusts readings with 

ratio obtained from adjacent 

gravimetric samplers 
pDR Field Calibration 

• Divide average gravimetric 

concentration by average pDR 

concentration for same sampling 

period 

• Multiply all individual pDR readings 

by ratio 

• Example: 

 gravimetric average = 1.4 mg/m3

 pDR average = 1.1 mg/m3 

 grav/pDR ratio = 1.4/1.1 = 1.27 

 pDR concentrations * 1.27 = adjusted pDR 

concentrations 
pDR Provides Time Record of Dust Levels 
Personal Dust Monitor 

(PDM) 

• Real-time measurement 

of respirable dust 

• Combines dust sampler 

and cap lamp into one unit 

• Sample inlet is mounted 

on cap lamp 

• Uses mass-based 

measurement to quantify 

dust concentration 

(TEOM) 

• Dust measurements are 

displayed on screen and 

stored internally for later 

analysis 
Principle of Operation

• Exchangeable filter cartridge mounted on 

the end of the tapered element collects 

particles as sample stream flows through 

hollow tube 

• Tapered element oscillates at a known 

frequency, like a tuning fork 

• Frequency changes in direct relation 

to the mass collected on the filter 

• Measurement principle does not respond to

other particle characteristics such as size 

distribution or composition (heated circuit 

removes moisture) 

Tapered 

element 

Flow 
PDM Status 

• Meets NIOSH sampling accuracy 

requirements (NIOSH RI 9669) 

• Equivalency to CMPDSU (gravimetric 

sampler) published in peer-review journal 

• MSHA intrinsic safety approval granted for 

use in underground coal mines 

• New CFR 30, Part 74 rule enacted in 2009 

• Thermo Scientific began delivery of 

commercial units in July 2009 

• Two ongoing NIOSH research efforts 

(software and silica) 
PDM Analytical Software

• Compile output from PDM samplers 

• Provide user-selected summaries for multiple samplers (foreman, 

mine superintendent, etc.) or engineering evaluations 

• Provide graphing capabilities 
PDM Filter Capsule for Maintaining Sample Integrity 

for Quartz Analysis

• Place capsule over PDM filter 

when TEOM unit removed 

from PDM 

• Use capsule as filter removal 

tool and to secure dust 

• Send to lab, remove finger 

tab, ash capsule 

• Plan to conduct mine surveys 

to complete side-by-side 

testing with current silica 

analysis method 
Sampling to Isolate a Fixed Dust Source 
Sampling a Mobile Position 
Using Real-time Data to 

Quant

Sources

ify Multiple Dust 

• Evaluate dust levels during truck 

haulage cycle at an underground 

gold mine 

• Use pDR samplers and time 

study data to quantify dust 

generation for different parts of 

cycle 

– loading 

– hauling full 

– dumping 

– hauling empty 

• Two researchers conducting time 

studies 
Time-weighted-average Dust Contributions 

Dump location had highest dust contribution despite having the 

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

Loading

15%

Tram

Full

22%

Dump

34%

Tram 

Empty

29%

(6.7 mins) 

(3.7 mins) 

(11.4 mins) (4.2 mins) 
Using Real-time Data to Quantify Dust Sources for 

Mobile Workers 

• Evaluate work tasks and associated dust levels for mobile workers 

throughout their shift 

• Merge active pDR 1500 sampling data and video (Helmet Cam) to 

quantify highest sources of dust generation for different tasks 

• Develop controls and/or improved work practices to reduce mobile 

workers’ dust exposure 
Sampling to Isolate an Unconfined Dust Source

A – Ambient sampling location 

 

A 

D 

D 

D D  

Wind direction 

D – Drill sampling locations 
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! 

Questions?? Questions?? 

Jay Colinet 

Office of Mine Safety and Health Research 

NIOSH 

P.O. Box 18070 

Pittsburgh, PA 15236 

412-386-6825 

jcolinet@cdc.gov