Here Comes The Helmet-CAM 

A Recent Advance In Technology can Improve How Mine Operators Investigat

And Assess Respirable Dust. 

BY Andrew B. tetala and Andrew D. O'Brien 

s on a miner's 

This article describes the latest advancements in technology to improve how mine operators can

investigate and assess the respirable

dust exposure of their workers. Recently, Unimin Corp. and the National

Institute for Occupational Safety and

Health (NIOSH) developed the HelmetCAM technology, a dust exposure assessment tool designed specifically for

the mining industry. 

This assessment technique is performed by having a miner wear a

small video recorder on his or her 

hardhat along with a real-time aerosol 

monitor that is housed in a backpack, 

on a safety belt, or safety vest and 

records the individual's respirable 

dust exposure at two-second intervals. After a miner performs his or her 

job while wearing the unit, the video 

and dust exposure data files are 

downloaded to a computer and then 

merged together using a NIOSH-developed computer software program 

called EVADE (Enhanced Video Analysis of Dust Exposure). 

By providing synchronized playback of 

the merged video footage and logged 

dust exposure data, the EVADE software allows for the assessment and 

identification of key work areas and 

processes, as well as work tasks that 

significantly impact a worker's personal respirable dust exposure. 

The Helmet-CAM respirable dust exposure assessment technology is now 

available for use and allows mining operators to quickly and efficiently identify work tasks, areas and practices 

contributing to respirable dust exposure, as well as to evaluate the effectiveness of implemented control 

techniques aimed at lowering worker's 

exposure to respirable dust. 

Figure 1 - Helmet-CAM setup showing video camera len

hardhat and 10-mm cyclone on backpack shoulder strap Cleft>. and 

video logg·er and pDR-1500 dust monitor in backpack <right>. 

Video L....-....,....---..,..,. 

camera 

lens - 1.1:1111!! 

Cyclone device to 

classify respirable 

particles 

Video camera 

logger 

Backpack to 

house video 

logger and dust 

monitor 

DUST MONITORING 

e

26 ROCKproducts • OCTOBER 2014 www.rockproducts.com 

Mining companies wishing to use this 

new dust exposure assessment technolo&y can purchase a commercially

available video camera and a directreading aerosol monitor to obtain the

necessary data. NIOSH has recently

released a beta version of the EVADE

software and user manual, which

can be downloaded from the NIOSH 

website at: www.cdc.gov /niosh/mining/Worksjcoversheet1867.html. 

Background on Respirable 

oust sampling 

The exposure of miners to respirable

dust, especially respirable dust containing crystalline silica, has been an

area of concern for decades, and the

adoption of permissible exposure limits upon the creation of the 1977 Federal Mine Safety & Health Act only

provided additional reasons to understand exposures and their sources. 

These personal dust sampling trains

are composed of a 10-mm Dorr-Oliver

cyclone, sampling pump calibrated to

1.7 liters per minute (lpm), 37-mm

polyvinyl chloride (PVC) filter, sampling

assembly, and a piece of tygon tubing.

The 10-mm cyclone has a 50 percent 

cut-point at four microns which is intended to replicate the respirable portion of dust that may reach the gas 

exchange region of a worker's lungs. It 

is this respirable dust - the dust that 

reaches the gas exchange region of the 

lungs -that can inflict injury to the lung 

tissue and may negatively impact pulmonary function. 

To perform personal sampling with the 

Dorr-Oliver cyclone, a 37-mm PVC filter 

is attached to the 10-mm cyclone via a 

stainless steel assembly positioned in 

the worker's breathing zone. A sampling pump calibrated to 1. 7 lpm draws 

dust-laden air through the cyclone. The 

respirable portion of dust is deposited 

via impaction on the 37-mm PVC filter 

and the non-respirable fraction (larger 

sized) of dust falls into a grit pot located 

at the bottom of the cyclone. 

The sampling pump is normally attached to the miner's belt and a short

section of flexible tygon tubing is then 

used to connect the sampling pump to 

the sampling assembly. The only significant change over the past few decades 
www.rockproducts.com ROCKproducts • OCTOBER 2014 27 

---------------ROCKPRODUCTS" 

to this sampling setup is in the sampling pumps; they have become smaller, 

lighter, have better battery-life, and are 

constant flow devices whereby the flow 

rate is maintained at the required 1. 7 

lpm flow rate. 

Once sampling is complete, filters are

submitted for analysis to an American

Industrial Hygiene Association (AIHA)

accredited laboratory. The miners' respirable dust concentration is determined by dividing the weight of

respirable dust by the volume of air collected over the period of sampling. 

The weight of respirable dust, reported

in micrograms or milligrams, is determined by pre- and post-weighing the

filter on a microbalance. The volume of

air, reported in cubic meters, is determined via multiplication of the total

sample time (obtained in one-minute

measurements on the sampling pump)

by the flow rate. 

If silica dust is believed to be present,

further analysis of the sample is performed, typically via the National Institute for Occupational Safety and Health

(NIOSH) 7500 method "Silica, Crystalline, by XRD (filter redeposition) .. "

This analytical method permits determination of the weight (and therefore,

percentage) of respirable crystalline silica (RCS) within the sample.

Ultimately; the worker's respirable dust 

concentration is compared to the permissible exposure limit (PEL) to determine

whether the miners' exposure was in excess of the PEL. If worker exposure exceeds 

the PEL, operators should investigate the

causes of the excessive exposure, make corrections, and resample to confirm effectiveness of the corrective interventions. 

Special Challenges

For exposures that exceed the PEL, 

identification of root causes can be

challenging, particularly if detailed operational or operator notes were not

kept. The challenges associated with

root cause identification can be especially difficult for workers who are mobile during their shift because they may

be constantly moving to different work

areas while performing multiple duties

and job tasks throughout the workday. 

In the metaljnonmetal mining industry;

mobile workers have some of the highest

overexposure rates for RCS for all the

various job occupation classifications.

Table 1 lists the overexposure rates of a

few mobile worker job categories for a

10-year period (2003-2012) based upon

MSHA's respirable dust compliance sampling results. In evaluating this data, a difficult challenge is determining the

primary contributors (i.e., tasks or

processes) to the respirable dust exposures exceeding the PEL. 

Over the years, video technology has

been used to evaluate worker exposure

to different types of contaminants, but

these evaluations were always performed with the camera in a stationary

position (Gressel et al., 1992; Rosen et

al., 2005). Unfortunately, these techniques were not applicable for mobile

workers in the mining industry because

of their need to move to various locations throughout the mining operation

to perform their work. 

Helmet-CAM Technology 

The newly developed Helmet-CAM

technology provides a first-person

video display of the job tasks performed by miners along with data on

their respirable dust exposure. In considering both sources of information simultaneously, immediate insight is

gained into work areas and/ or tasks

that contributed to elevated respirable

dust exposures (Cecala et al., 2013). 

Helmet-CAM was developed under a 

co.operative relationship between 

Unimin and NIOSH. The original goal 

was to be able to evaluate a workers' 

respirable dust exposure without the 

need to closely follow a worker and observe or monitor the worker to determine his or her exposure. 

The possibility of combining a small

video camera with an instantaneous

dust monitor to determine a worker's

respirable dust exposure seemed like a

viable methodology. The next step was

finding a means to compare the video

and dust data simultaneously. This led to

the development of the EVADE software,

which merges these two pieces of inforTable 1. Silica overexposure rates for mobile workers in the metal/nonmetal 

industry from MSHA data from 2003 to 2012. 

sand and Gravel Mines Stone Quarries Metal Mining Mines 

occupation %>PEL Total 

samples 

%>PEL Total 

Samples 

%>PEL Total 

samples 

Laborer 15 1187 10 1864 16 120 

Mechanic 4 240 5 365 13 174 

Utility Man 10 435 10 1246 22 72 

Cleanup Man 16 633 11 793 21 80 
Figure 2 - The video taken by Helmet-CAM is in the top right corner

and the respirable dust control graph appears along the bottom of

the screen. Each blue dot on the graph represents a 2-second respirable dust measurement. This Helmet-CAM unit was inside the enclosed cab of a haul truck. 

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28 ROCKproducts • OCTOBER 2014 www.rockproducts.com 

DUST MONITORING 

mation (logged respirable dust data and

video) in a user-friendly format. 

Helmet-CAM is a simple and relatively 

inexpensive technology to set up and 

use. It consists of a lightweight video 

camera, an instantaneous dust monitor, 

and a method for housing these two instruments in a way that allows miners 

to perform their work in a safe and 

unimpeded fashion. Once the video 

footage and dust data are obtained, the 

information is downloaded to a computer and the EVADE software is used 

to merge the video and dust data together, permitting quick and effective 

assessment of the areas, tasks, and 

functions that impacted the miner's 

respirable dust exposure. 

Although there are a number of different types of commercially available 

cameras and dust monitors that can be 

used, we will only discuss the units 

used by Unimin and NIOSH during testing of this new technology. 

Helmet-CAM Components 

The first component necessary to employ

the Helmet-CAM system is a small compact video camera that records the

worker's movements and tasks performed while wearing the system. The

video unit chosen for NI OSH' s testing was 

the POV (point of view) camera by V.I.O. 

This camera lens was attached to the

miner's hardhat using various methods

(flashlight clip, video camera mounting

device, or duct tape). With the V.I.O. unit,

a thin video cable approximately 18 in. in

length connects the video lens to the digital video recording portion of the device. 

The second component of the system is 

the instantaneous dust monitor. NIOSH 

chose the Thermo Scientific pDR-1500 

instantaneous monitor for the HelmetCAM testing. Because this instrument 

was relatively new, NIOSH performed a 

comprehensive laboratory study at its 

Pittsburgh laboratory to ensure that the 

unit provided comparable dust data 

similar to what would be obtained with 

MSHA compliance and in-house gravimetric dust sampling [Reed et al. 2012]. 

The pDR-1500 was also set to a 1.7-lpm 

flow rate, which is the required flow 

rate as established by the American 

Conference of Governmental Industrial 

Hygienists (ACGIH) for the metal/nonmetal industry [Mine Safety and Health 

Administration 1990]. 

The next component for a Helmet-CAM 

assessment is a 10-mm cyclone, placed

on the miner's lapel. This location is 

classified as being within the miner's 

breathing zone and is identical to the 

location used for a gravimetric compliance-type dust sample. 

A short length of conductive tubing is

used to connect the cyclone to the main

body of the pDR-1500 monitor. The instantaneous dust monitor should be

configured to take frequent samples for

testing, which for the NIOSH testing

was on a two-second sampling interval.

The last necessary item is some type of 

method to house the video camera and 

dust monitor to allow the miner to 

perform his or her work safely and 

with minimal interference. The authors recommend providing a number 

of different options to house the instruments (backpack, safety belts, and 

safety vests) and allowing the wearer 

to choose the preferred method. 

Figure 1 shows a typical sampling setup 

using a backpack arrangement with the 

video camera lens on a miner's hardhat 

and the rest of the components housed 

either in or on the backpack. 

Helmet-CAM usage 

One aspect critical to effective use of the 

Helmet-CAM technology is that both the 

video camera and dust monitor need to 

be started at the exact same time because 

there is no adjustment within the EVADE 

software to synchronize the video and 

dust data. 

Once both units are simultaneously 

started, miners should be instructed to 

perform their routine job duties and 

tasks without any changes or deviations 

because they are wearing the device. The 

miner should also be provided with a 

time frame to wear the Helmet-CAM system - usually recommended to be somewhere between two and four hours to 

ensure comprehensive data collection. 

Once the miner returns the system after 

the pre-arranged time period, the video 

and respirable dust exposure data files 

are downloaded to a computer. 

Using the EVADE Software

Once the miner returns from performing his or her work duties, both the dust

monitor and video camera data are 
downloaded to a computer which has 

the EVADE software installed, using a 

specific management site defined 

nomenclature to identify the miner. 

When the EVADE program is opened,

the top menu bar provides the following options: File, Bookmarks, Playback,

View, Options, and Help. The user

chooses "File" and then has the following options: Open, New, Export Bookmarks, and Exit. From this list, the user

chooses the "New" tab and then directs

the software to the location of the video

and dust data files. 

The "New" tab is used when performing

an analysis for the first time. (Note: It is

important that the video file be in either

the avi or mp4 file format, and that the

dust data file be in csv format. The video

file and dust file must also be located in

the same file folder on the computer for

EVADE to successfully merge these two

files.) Once the "EVADE" user's screen appears with the video in the upper righthand portion, the program is ready to be

used to perform the dust exposure assessment (see Figure 2). 

Retrieving Recorded Data

When the "Start" button is activated,

the video starts to play in the upper

right-hand corner of the screen. Across

the bottom of the screen, the dust data

is shown. In the graph, a vertical green

bar is visible in the center of the screen

that shows the exact dust data point

which corresponds with the video data

being shown. 

One extremely useful feature of the 

EVADE software is the zoom function, 

which allows viewing of the dust data 

in a wide spectrum range on the screen 

based on the level of detailed desired. 

By sliding the zoom tab, the viewing 

screen can range from a few seconds to 

multiple hours. 

To allow easily retrievable access to the 

highest exposure data, the EVADE software program automatically creates 

bookmarks for the five highest dust 

concentration peaks, as well offers as 

the option of creating additional bookmarks. Users can easily create and label 

their own bookmarks if they wish. 

These bookmarks are especially beneficial for safety meetings and other presentations, allowing presenters to 

quickly advance to segments of the 

video and dust data to show elevated 

exposures. 

Another method used to advance

through EVADE footage is the "Scroll"

option and "Drag" function. This allows

the user to quickly move through the

footage without having to watch the

data in real-time. A final noteworthy

feature of the EVADE software is the use

of screenshots. 

Screenshots are jpg files that depict exactly what the EVADE screen is showing when the screenshot is created.

These screenshots are especially beneficial for safety meetings and other presentations. The image files can be

inserted easily into Word documents

and PowerPoint presentations, and 

they were used to create the figures 

representing the EVADE software in 

this article. 

There are many additional functions and

options available with this software, and

NIOSH has published a report entitled

"Guidelines for Performing a HelmetCAM Respirable Dust Survey and Conducting Subsequent Analysis with the

Enhanced Video Analysis of Dust Exposure (EVADE) Software" [Reed et al.

2014]. The EVADE software is available

under Helmet-CAM at NIOSH's website:

www.cdc.gov jnioshjmining. 

Validation of Technology 

The initial field test of this new technologywas performed at Unimin's Gore

Facility located in Gore, Va. After anumber of issues were identified and resolved from this field test, NIOSH

performed a number of additional field

studies to evaluate the effectiveness of

the Helmet-CAM technology as a

method of determining elevated respirable dust exposures for miners. 

To date, more than 100 different individuals have worn the Helmet-CAM

unit with only one worker refusing to

continue wearing the unit after about

an hour because he stated that it was

hurting his back. In a number of cases,

after a worker was allowed to view

the EVADE software footage of the

video and respirable dust data merged

together, the worker asked to wear the

unit again on the second day of testing

Figure 3 - Left side shows screenshot of EVADE software of miner performing manual deployment of 

scraper device with high peak in dust exposure shown in the bottom of the screen; right side shows 

photo of new pneumatic system to eliminate worker performing the task. 

www.rockproducts.com ROCKproducts • OCTOBER 2014 29 

---------------ROCK PRODUCTS" 
DUST MONITORING 

in order to perform other duties and 

tasks not performed on the first day. 

case study 

This section details a case study to implement an automated device to remove wet sand when a screening

process was started. When production

was down for an extended period of

time, it was common to encounter wet

material which is problematic for the

screening process. 

Wet or damp material can cause

screens to clog or glaze over. This situation creates undesirable maintenance

and productivity difficulties. Historically, to prevent wet material from

reaching the screening process, a

process helper would manually place a

diverter on the screen house feed conveyor belt until the product was dry. 

With this process helper wearing the

Helmet-CAM technology, it was determined that his respirable dust exposure was greatly elevated while

performing this task. In order to eliminate this respirable dust exposure,

the operator installed an automated

system that allowed the process operator, from his control room, to: (a) determine the moisture content of the

material going to the screen house,

and (b) engage a remote-control diverter to keep wet material from

reaching the screening process. 

Once the material was determined to

be at an acceptable moisture content,

the process operator would remotely

deactivate the diverter and the product would be directed to the screening

house. Figure 3 shows a screenshot o

the process operator's exposure while

performing this task manually, as well

as the new automated device which

eliminated the need to for the worker

to perform the task manually. 

f

Through use of the Helmet-CAM technology, the operator was able to effectively and efficiently determine the

process operator's exposure to respirable dust which resulted in system

automation and reduction of process

operator exposure to respirable dust

30 ROCKproducts • OCTOBER 2014 www.rockproducts.com 

over the course of his shift. 

Through additional field studies, many

other examples of respirable dust reduction were achieved through implementation of engineering, administrative or

work practice interventions. 

conclusions 

Despite developments in technology,

the ability to determine a miner's exposure to various types of respirable

contaminants has not advanced substantively over the past few decades.

With mobile workers performing

many different types of tasks and functions in many different locations

throughout the workday, it can be extremely difficult and resource intensive to determine where a worker is

being exposed to respirable dust

through traditional time study methods. The Helmet-CAM technology has

proven to be a viable tool to perform

this assessment and determine where

and when a mobile mine worker is

being exposed to respirable dust. 

Although this assessment tool was originally developed for respirable dust, it

is in the process of being expanded to

assess other contaminants, and is currently being investigated by NIOSH for

diesel exhaust (elemental carbon),

noise exposure, and chemical assessments. It is envisioned that future versions of the EVADE software may be

able to simultaneously evaluate exposures to multiple contaminants using

the same video footage. . 

f

The Helmet-CAM technology is currently available for the assessment of

worker's respirable dust exposure in

mining. To utilize the technology, an interested mining operation has to purchase a video camera and a real-time

instantaneous dust monitor. The

EVADE software package and user's

manual are available for free at NIOSH's

website, www.cdc.gov jnioshjminingj.

Acknowledgments 

NIOSH would like to thank the following 

companies who participated in testing

the Helmet-CAM technology: Unimin 

Corp., U.S. Silica Co., Badger Mining Co., 

3M Corp., Sidwell Limestone Mine and

Shelly Materials Co. 

Disclaimer 

Mention of any company or product does 

not constitute endorsement by the National Institute for Occupational Safety 

and Health. The findings and conclusions 

in this report are those of the authors 

and do not necessarily represent the 

views of the National Institute for Occupational Safety and Health. + 

Andrew B. Cecala is with NIOSH, Pittsburgh, and Andrew D. O'Brien is with 

Unimin Corp., Winchester, Va. 

References 

Cecala, A.B., Reed, WR, joy, Gj., Westmoreland S.C., and O'Brien, A.B. 2013. HelmetCAM: Tool for Assessing Miners' Respirable

Dust Exposure. Mining Engineering, 65(9):

78-84. 

Gressel, M.G., Heitbrink, WA.,]ensen, P.A., 

Cooper, T.C., O'Brien, D.M., McGlothlin, 

].D., Fischbach, T.]., and Topmiller, ].L. 

1992. Analyzing Workplace Exposures 

Using Direct Reading Instruments and 

Video Exposure Monitoring Techniques. 

Mine Safety and Health Administration 

(MSHA). 1990. Metal, Nonmetal Health 

Procedures Manual (PH90-IV4}, Chapter 

D, Arlington, Virginia. 

Reed, WR., Potts, ].D., Cecala, A.B:, and 

Archer, W]. 2012. Use of the pDR-1500 

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2012 SME Annual Meeting & Exhibit, 

Feb. 19-22, 2012, Seattle, Washington. 

Reed, WR., Kwitowski, A.]., Helfrich, W, 

Cecala, A.B., and joy, ].G. Guidelines for

Performing a Helmet-CAM Respirable

Dust Survey and Conducting Subsequent

Analysis with Enhanced Video Analysis

of Dust Exposures (EVADE) Software.

NIOSH R/9696, 2014, 92 pp. 

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R.D.R., Saamanen, A., Heinonen, K, Riipinen, H., and Paakkonen, R. 2005. A Review ofVideo Exposure Monitoring as an

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