SIMPLE SOLUTIONS 

FOR DUSTY ENVIRONMENTS 

AT METAL/NONMETAL MINES 

REDUCING DUST EXPOSURES 

WHILE IMPROVING ERGONOMICS 

Centers for Disease Contro l

and Prevention 

National Institute for Occupational 

Safety and Health 
Disclaimer 

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Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC). In addition, citations to websites 

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 websites. All web addresses referenced 

in this document were accessible as of the publication date. 

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Suggested Citation 

NIOSH [2021]. Simple solutions for dusty environments at metal/nonmetal mines. By Patts JR, Pollard JP, Cecala 

AB, Dempsey PG, Louk AK, Schall J. Pittsburgh PA: U.S. Department of Health and Human Services, Centers for 

Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication 

No. 2022-107. https://doi.org/10.26616/NIOSHPUB2022107

DOI: https://doi.org/10.26616/NIOSHPUB2022107

DHHS (NIOSH) Publication No. 2022-107

December 2021

This document is in the public domain and may be freely 

copied or reprinted.
Contents

Foreword ....................................................................................................................................................................1

Common Contributors to Dust Exposure ...................................................................................................................2

Musculoskeletal Disorder/Traumatic Injury Risk Factors..........................................................................................3

Ladder Climbing..........................................................................................................................................................4

Manual Palletizing ......................................................................................................................................................5

Screen Changeout ......................................................................................................................................................6

Work Boot Cleanliness................................................................................................................................................7

Hose Handling.............................................................................................................................................................8

Floor Cleaning.............................................................................................................................................................9

Filter Accessibility .................................................................................................................................................... 10

Belt Conveyors......................................................................................................................................................... 11

Enclosed Control Rooms.......................................................................................................................................... 12

Bulk Bagging ............................................................................................................................................................ 13

Broken Bag Disposal ................................................................................................................................................ 14

Additional Resources............................................................................................................................................... 15
Foreword

This booklet, Simple Solutions for Dusty Environments at Metal/Nonmetal Mines, is designed to provide 

examples of the types of solutions that you can use to reduce exposure to dust at surface mines and facilities.

Practical controls are presented that not only lower dust exposures but also reduce the risks for both

musculoskeletal disorders (MSDs) and traumatic injuries (e.g., slips, trips, and falls). Beyond the obvious health 

benefits, it can be easier to justify engineering controls and interventions when greater impact can be achieved.

While traumatic injuries occur suddenly, both MSDs and respirable diseases tend to be the result of cumulative 

overexposures. Exposures both at home and at the workplace can combine and manifest themselves in the later 

years of your career, depending on your exposure rates and cumulative stress.

This booklet provides information based on experience gained within the National Institute for Occupational 

Safety and Health (NIOSH) and highlights solutions that are relatively low in cost and easy to implement. Dust 

control solutions that are practical to maintain have the greatest potential for sustained use and ultimately 

improved mine worker health and safety. The information provided is only a primer on dust control and injury 

prevention at metal/nonmetal mining operations. For more comprehensive coverage of these topics, please 

consult the “Additional Resources” section at the end of this booklet.
2

Common Contributors to Dust Exposure

While any situation that releases dust into the air that workers breathe causes exposure, researchers have 

gained a body of experience (see “Additional Resources” section at the end of this booklet) that points to several 

common contributors, as described below. While this document focuses on respirable dusts, engineering 

controls which are able to reduce these smaller dusts should also work effectively on larger dusts (inhalable and 

thoracic). Throughout this document it can be assumed that “dust” refers to any size range but with an 

understanding that the most damaging health effects are caused by respirable dusts. Taking action to reduce 

emissions from these dust sources can reduce the potential for chronic health impacts from respirable dust 

exposures.

▪ Inadequate Housekeeping can take on many forms and has an impact anywhere that accumulated material

is then released into the air.

- Buildup of material on interior structures (beams, walls, ceilings of indoor enclosures) as well as the

inside of interior structures (equipment cabinets and shelves, etc.)

- Accumulation of spilled material at conveyors, transfer points, etc.

- Excessive material on floors brought in from mobile equipment

▪ Lack of Effective Local Exhaust Ventilation can allow dust to spread throughout the plant.

- Local exhaust ventilation systems that are not operational, missing, blocked, or with holes in ductwork

compromising performance

- Insufficient draw (negative pressure) to carry away dust

- Poorly designed or oriented hoods or inlets too far away from the source

▪ Lack of Total Structure Ventilation may increase dust concentrations in indoor spaces leading to elevated

exposures.

- Fans that are turned off or otherwise not operational

- Fans mounted too low in the building

- Outside air inlets located near dust sources, allowing dusty air to enter the structure

▪ Lack of Effective Enclosure Filtration can lead to dust exposures for workers who spend much of their shift

within enclosed cabs, booths, and control rooms.

- Use of ineffective HVAC (heating, ventilation, and air-conditioning) systems; residential AC units without

adequate filtration

- Use of over-restrictive filters that can reduce airflow and clog too quickly

- Lack of cab pressure monitors that provide real-time feedback on a booth’s seal and system

performance

▪ Poor Worker Practices can lead to unnecessary dust exposures as workers allow their work habits and

behaviors to expose them to respirable dusts.

- Clapping hands to “clean off” gloves

- Allowing one’s face to be too close to dust emissions (while bag tying and sealing, hosing down, etc.)

- Handling of dusty equipment, bags, boxes, screens, etc.

Note: Multiple respirable dust sources can be present simultaneously. This list is not all-inclusive but rather 

serves as a starting point in a complete dust assessment.
3

Musculoskeletal Disorder/Traumatic 

Injury Risk Factors

A musculoskeletal disorder (MSD) risk factor is an action or condition that has been found to contribute to a 

musculoskeletal injury. MSDs may be characterized by discomfort, pain, and limitations in mobility and dexterity 

that may affect a person’s ability to work. Five fundamental risk factors are described below, including 

examples.

▪ Forceful Work is any task or activity where the body must exert high levels of effort.

- Lifting or carrying heavy objects

- Forcefully pulling, pushing, or prying

- Forceful gripping

▪ Poor Posture occurs when workers use any position other than a neutral posture, which makes them less

capable of generating force and may cause pinching of nerves. Poor posture is sometimes also generally

referred to as “awkward” posture.

- Bending over to reach objects below knuckle height

- Twisting the upper body or head

- Working with elbows above the shoulders

- Extended reaches in front of or behind the body

- Kneeling or squatting

- Static posture—even good posture can be harmful when sustained for a prolonged period

▪ Repetitive Work occurs when workers repeatedly use the same muscles and tissues to perform a task or

activity, irritating tendons, increasing pressure on the nerves, and keeping the body from healing properly.

- Pinching bags to seal them

- Manually tightening bolts

- Using mobile equipment controls such as joysticks

- Using manual grease guns

- Extended computer work at stations without concern for ergonomics

▪ Vibration Exposure comes in two forms: hand-arm and whole-body. Vibration exposure can decrease blood

flow, damage nerves, contribute to muscle fatigue, and cause low back pain.

- Driving a haul truck or other mobile equipment on uneven terrain

- Operating a crusher

- Using a jackhammer

▪ Slip, Trip, and Fall Hazards are the second leading cause of injury at surface mines.

- Contaminants on walking surfaces (grease and oils, excessive spillage, etc.)

- Unstable working surfaces

- Inadequate barriers

Note: Multiple MSD risk factors may be present simultaneously. The risk of injury increases as the number of 

risk factors present increases.
4

Ladder Climbing

When a worker ascends or descends a ladder in a dusty environment, dust can be liberated from the ladder as 

the worker grabs or steps on the rungs. This dust can then fall directly into the worker’s breathing zone and

increase his or her dust exposure. Dusty ladders can also pose a slipping and falling risk as settled dust 

decreases the available friction on rungs and railings.

Risk Factors: Dust: inadequate housekeeping; MSD/traumatic injury: slip, trip, and fall hazards

 Photo by NIOSH

Problem: Dust is released into the air from the 

ladder as a worker grabs or steps onto each rung 

during ascent or descent.

Solution: When possible, use angled stairways 

(in blue, right) as opposed to vertical ladders 

(top photo). When floor space is limited, consider 

alternating tread stairs (yellow, left), which offer a 

much smaller footprint while still providing some 

of the ergonomic and safety advantages of 

traditional stairs. An unpublished case study 

suggests that both types of ladders reduce the 

chances of dust being released into the worker’s 

breathing zone.

Additional Improvements: Good housekeeping is vital to reducing workers’ respirable dust 

exposures. Walking surfaces and handrails should be hosed down to reduce dust accumulation.

Use caution on these wetted surfaces until they have dried.
5

Manual Palletizing

During the bag filling process, the exterior surfaces of bags can become contaminated with dust. This dust can 

then be released into the air as the bag is handled by workers manually performing palletizing tasks. Lifting 

and lowering bags frequently can also cause fatigue and lead to injury. Injury risks are increased when the 

locations of the pallets are not ideal or the weight of the bags is excessive. Additionally, the dust that settles 

on the walking surface in the palletizing area can often make the floor slippery, increasing the potential for a 

slip or fall.

Risk Factors: Dust: lack of effective local exhaust ventilation; MSD/traumatic injury: poor posture; slip, trip, 

and fall hazards

 Photo by NIOSH

Problem: Manually palletizing bags often requires

awkward postures. Initially the bags must be placed 

on top of an empty pallet below waist height while as 

the pallet fills, workers may reach with their hands 

above the shoulders to place bags on top of the pallet. 

Soiled bags and bag leakage combined with minimal 

ventilation also expose workers to respirable dust.

Additionally, dust can contaminate worker clothing 

and create a secondary source of exposure.

Solution: Semi-automated systems include workers 

and an automated system to perform the bag stacking 

process. The lift table illustrated in yellow allows the 

bags to remain at approximately knuckle height for 

the worker to stack them, which is the most 

ergonomic loading height. A push-pull ventilation 

system entrains dust released during the stacking 

process into a local exhaust ventilation system, 

keeping it from entering the worker’s breathing zone.

Additional Improvements: Consider using fully automated bagging solutions such as form-fill-seal 

systems that (1) isolate the bag filling to an area away from the worker and (2) eliminate bag 

handling entirely due to fully automated bag forming, filling, sealing, and conveyance. For more

information on form-fill-seal systems, see the following resource:

https://www.cdc.gov/niosh/mining/UserFiles/works/pdfs/2019-124.pdf#page=272
6

Screen Changeout

Screens are used at mineral processing operations to size material, which almost always generates large amounts 

of dust into the work environment, especially during maintenance and changing of screens. Screens must be 

maintained and replaced as needed, and careful attention to this work will reduce the dust hazard to workers. 

The screen frames are heavy, large, and difficult to handle. Also, the used screens must be carefully removed and 

new screens must be stored and installed.

Risk Factors: Exposure to dust: poor worker practices; inadequate housekeeping; MSD/traumatic injury: poor 

posture; forceful work

Photo by NIOSH

Problem: Screen cleanings and changes involve 

exposure to high amounts of dusts. Traditional 

screen decks are large and heavy and require 

repeated unclipping and reclipping; therefore, if 

these tasks are not performed properly, they can 

be a source of dust exposure as well as causing

workers to exert high force, overreach, and work in 

awkward positions.

Photo by NIOSH

Solution: Newer, multi-panel screen decks are 

handled more easily by individual workers. These 

newer decks eliminate the need to perform the 

clipping process, and screen mesh reduces the 

worker’s exposure to dusts. While respiratory 

protection is typically implemented only as a last 

resort when engineering controls cannot be used, 

dust release during screen maintenance can be 

hazardous and difficult to control. Therefore,

respiratory protection should be used when

performing this task.

Additional Improvements: Store new screens where they will be protected from collecting surface 

dust deposits that can further expose workers when they install the screens. Consider using a 

separate work stand outfitted with a local exhaust ventilation system for screen deck maintenance. 

Overhead hoists and lifting devices can reduce strain on workers when installing larger screens.
7

Work Boot Cleanliness

Dirty work boots can be a source of background dust exposure to workers and occurs when a worker walks 

through wet product, overburden, or mud and the material adheres to the work boots. Once a worker’s boots 

are soiled with product, it is then tracked everywhere they go until it either falls off or the boots are cleaned. 

Muddy work boots have also been identified by mine workers as a risk factor for slips and falls during mobile 

equipment ingress and egress.

Risk Factors: Dust: inadequate housekeeping; poor worker practices; MSD/traumatic injury: slip, trip, and fall 

hazards

 Photo by NIOSH

Problem: Soiled work boots can track dirt into the cabs of 

mobile equipment. This leads to the accumulation of dust on 

the cab floors, which can lead to dust exposure while 

operating equipment.

 Photo by NIOSH

Solution: Provide designated walkways and boot brushes at 

mobile equipment parking areas to help workers remove 

contaminants from their boots prior to getting on equipment.

Boot brushes should always be located outdoors to avoid 

exposure to re-aerosolized dust.

Additional Improvements: Designated walkways should be provided and maintained to be free 

from contaminants. Grated metal walkways can be used to help remove accumulations from 

boots and prevent pooling of liquid contaminants.
8

Hose Handling

Handling hoses for washdown or cleanup activities can present a respirable dust hazard, as the hose jacket 

itself can collect dust which is then released as workers slide their hands over it. Long hoses that are typically 

required at mine sites not only acquire more settled dust but put undue strain on the worker’s back due to 

their weight.

Risk Factors: Dust: poor worker practices; inadequate housekeeping; MSD/traumatic injury: poor posture;

slip, trip and fall hazards

Photo by NIOSH

Problem: The large surface area of hose jackets can collect substantial 

amounts of respirable dust and must be directly handled by workers 

when performing washdown operations. Workers often handle the hose 

close to their breathing zone, making the problem that much worse.

Photo by NIOSH

Solution: Before the hose is unreeled, the coiled or rolled hose should be 

sprayed off to knock down and wet any residual dust. Holding the hose at 

an ergonomic position (about knuckle height) will also keep any dust 

released further away from the worker’s breathing zone.

Additional Improvements: Consider using a small horizontal roof or cover over the hose reel to 

reduce the amount of dust that can accumulate on the hose. To reduce muscle strain, consider 

using additional hoses closer to the washdown areas as opposed to fewer hoses that must be 

dragged throughout the plant.
9

Floor Cleaning

Effective housekeeping is vital to ensuring a safe work environment. Because of the traffic that takes place over 

plant floors, effective housekeeping must include the removal of loose material (a future dust source) from the 

floors. Not only does routine cleaning and housekeeping remove accumulations of dust that can be released 

and inhaled, it also removes other contaminants (such as oil, grease, etc.) on walking and working surfaces that 

increase the potential of slips, trips, or falls.

Risk Factors: Dust: inadequate housekeeping; MSD/traumatic injury: slip, trip, and fall hazards

Photo by NIOSH

Problem: Although hosing down working areas is an effective 

means of removing dust accumulation, it should be performed 

at the end of work shifts so that pooled walkways and wet 

surfaces have more time to dry before the next shift is started.

Hoses can pose tripping hazards during use and when not 

properly stored.

 Photo by NIOSH

Solution: Hosing should begin by using a nozzle with a wide fan 

pattern, as shown, to initially wet the material and progress 

towards more narrow streams to push material either towards 

drains or out of the building. Using a concentrated narrow 

stream can cause accumulated dust to become airborne before 

it has become wetted.

 Photo by NIOSH

Solution: For within-shift cleaning, rideable floor sweepers can 

be used to clean dust-laden floors without introducing excess

water than can lead to pooling of liquids and increased slip 

risks.

Additional Improvements: If water sprays are used to hose down areas with accumulated dust, 

ensure that adequate drainage is in place to route the water away from walking areas.
10

Filter Accessibility

Enclosure filtration systems, whether on mobile or stationary equipment, have the potential to greatly reduce 

the dust levels inside the enclosure where workers spend much of their time performing their duties. However, 

these systems are only as good as the initial design, and they require routine maintenance to maintain their 

effectiveness. Careful attention must be given to the design and location of these systems to ensure easy 

maintenance that does not pose a dust or ergonomic hazard in itself.

Risk Factors: Dust: ineffective enclosure filtration; MSD/traumatic injury: poor posture; slip, trip, and fall hazards

 Photo by NIOSH

Problem: The plenums for the ventilation system are

located on top of the structure, requiring a ladder (a 

fall hazard) and potentially exposing the worker to 

deposited dust.

Solution: The illustrated filter system is located at 

waist height in an easily accessible location on the 

side of the booth. Only a simple tool is needed to 

open the filter housing.

Additional Improvements: Consider using MERV 16 filters instead of HEPA filters. For mining 

applications with very high dust levels, MERV 16 filters load less quickly, keeping airflow quantities

high while still having relatively high dust trapping capability. For more information, download this 

infographic: https://www.cdc.gov/niosh/mining/works/coversheet2109.html.
11

Belt Conveyors 

Material spillage along and especially from belt conveyors at transfer points is caused by inadequate material 

control. Not only can this spillage result in increased dust exposures, but manually cleaning spillage can expose 

miners to risk factors for shoulder and back MSDs.

Risk Factors: Dust: inadequate housekeeping; MSD/traumatic injury: forceful work; slip, trip, and fall hazards

Problem: Poor material loading onto a conveyor belt leads to 

spillage and ultimately causes belt damage. Spillage into walkways 

can increase dust exposure, poses a slip and fall risk for nearby 

workers, and eventually must be shoveled away, which can cause 

back strain and exposure to dust.

Solution: Rock boxes can be used to soften the drop and redirect the 

flow of falling material into the center of the belt.

Additional Improvements: To effectively control spillage at transfer points, ensure the following 

requirements: (1) the material is fed to the center of the belt, (2) the vertical fall distance of the 

material is minimized, (3) the transfer material is well contained, and (4) the transfer distance is 

reduced to the extent practicable.
12

Enclosed Control Rooms

Many operations, during processes ranging from primary crushing to loadout, can generate substantial 

amounts of dust. Along with the exposure to dust, workers may also be exposed to high noise levels and 

whole-body vibration, particularly inside enclosed control rooms.

Risk Factors: Dust: ineffective enclosure filtration; MSD/traumatic injury: vibration exposure

 Photo by NIOSH

Problem: Window air conditioners, commonly 

installed in control rooms or operator booths, do not 

provide adequate air filtration. These units are 

typically installed in a rough opening (not sealed) and 

do not have enough airflow (in cubic feet per minute) 

or filtration efficiency (dedicated filter media) to 

reduce respirable dust concentrations. Further, 

control rooms and booths must be sealed and

pressurized to prevent wind-carried dust from 

penetrating, and they must have a dedicated highefficiency air filtration and pressurization system 

installed. Often, control booths are directly mounted 

to decking or structures that vibrate along with the 

crushing operation activities which produces 

substantially more dust inside the booth from the 

vibration.

Photo by NIOSH

Solution: Providing a separate, positively pressurized 

control room for workers can provide substantial

reductions in dust exposures. Moreover, when isolated 

from the surrounding equipment, the worker’s exposure 

to noise and whole-body vibration can also 

be reduced.

Additional Improvements: Consider asking your booth or HVAC system supplier to verify the 

performance of the operator booth. Ask the fundamental question: How well does it protect the 

occupants from dust, and how is that protection measured?
13

Bulk Bagging

Bulk bagging with flexible intermediate bulk containers (FIBCs) is commonly used at many industrial mineral 

operations as they prepare truck shipments to customers. FIBC filling tasks put workers very near the 

loading/transfer point of material. Both dust and ergonomic considerations can be optimized when a full job 

analysis is completed on bagging operations, including bulk bagging practices by workers.

Risk Factors: Dust: poor worker practices; MSD/traumatic injury: poor posture

 Photo by NIOSH

Problem: Tying bag collars can expose workers 

to dust as air is pushed out of the collar area, in 

particular if the collar is in the worker’s 

breathing zone. Note how in the photo the 

collar of the bag is directly in the worker’s 

breathing zone, as indicated by the red arrow.

 Photo by NIOSH

Solution: Bag collars should be tied as much as 

possible away from the breathing zone of the 

worker. The bag collar should be angled away 

from the face and the head should be kept

back and away from the bag. Note how the 

collar in the bag is a few feet away from the 

worker’s breathing zone, as indicated by the 

green arrow.

Additional Improvements: Minimize the fall distance of material to bulk bags when possible to 

reduce dust emissions. Use ergonomic work platforms that raise or lower the bag to the worker’s

comfortable working height and keep the worker’s breathing zone away from the filling area to 

the extent possible. Install a local exhaust ventilation system to capture dust around the material 

transfer point.
14

Broken Bag Disposal

Occasionally bags filled with product break and must be discarded. This can be a significant dust source to 

workers in and around the bag loading and stacking area and can require additional manual handling (lifting, 

carrying) of bags. Bags that break as a result of falling off conveyors can also require lifting from the ground 

while bending and twisting the back, which increases injury risk. The method in which these broken bags are 

disposed of and the careful handling of broken bags by workers will ensure that hazards are minimized.

Risk factors: Dust: poor worker practices, lack of effective local exhaust ventilation; MSD/traumatic injury: 

poor posture

 Photo by NIOSH

Problem: Broken bags discarded into a dumpster can cause 

material accumulation on the dumpster as well as the floor

and serve as a dust source inside the plant. Dust can be 

released in the work environment and can contaminate

multiple workers. Transporting bags to a dumpster is often 

performed manually and increases the risk of 

musculoskeletal disorders.

 Photo by NIOSH

Solution: Broken bags should be handled carefully and, 

when possible taken to a ventilated product recovery 

station or outside the plant.

Additional Improvements: Address bag defects, venting issues, rough handling, etc., and correct the 

circumstances that lead to broken bags. After the salvageable product has been recycled, the empty 

bag with its residue should be placed in a dumpster located underneath a ventilation hood. Ensure 

that workers are trained in proper disposal techniques and that supervisors track the number of 

broken bags so that their occurrence can be reduced. Consider the installation of an optimal design, 

which is an automated system that does not require workers to handle the bags.
15

Additional Resources

The NIOSH Mining Program has a number of resources available relevant to reducing and eliminating dust

exposure, musculoskeletal disorders, and slip, trip, and fall hazards in mine operations.

Dust Control Handbook for Industrial Minerals Mining and Processing

This handbook provides detailed information on control technologies to address all stages of 

the minerals handling process, including drilling, crushing, screening, conveyance, bagging, 

loadout, and transport. The handbook aims to empower minerals industry personnel to apply 

state-of-the-art dust control technology to help reduce or eliminate mine and mill worker 

exposure to hazardous dust concentrations.

Download: https://www.cdc.gov/niosh/mining/works/coversheet2094.html

ErgoMine

This ergonomics audit tool is designed specifically for mining. It includes audits for bagging, 

haul truck, and maintenance and repair operations at surface mining and processing facilities. 

Based on the user’s responses to the audit questions, ErgoMine provides recommendations 

when there is an opportunity for ergonomics improvement. ErgoMine can be downloaded for 

free on Android devices from the Google Play Store.

Download: https://www.cdc.gov/niosh/mining/works/coversheet1906.html

Simple Solutions for Surface Mine Workers

This booklet provides examples of the types of solutions and task design ideas that can be 

used to reduce exposure to risk factors for musculoskeletal disorders and slips, trips, and falls.

Simple Solutions for Surface Mine Workers can be downloaded from the NIOSH Mining 

website. A printed version can also be requested by emailing mining@cdc.gov.

Download: https://www.cdc.gov/niosh/mining/works/coversheet2036.html

Slip, Trip, and Fall Prevention for Mining 

This webpage contains extensive background information and mining-related resources to 

prevent slips, trips, and falls.

Visit: https://www.cdc.gov/niosh/mining/content/STFprevention.html
Promotingproductive workplaces through safety and health research 

DHHS (NIOSH) Publication No. 2022–-107

DOI: https://doi.org/10.26616/NIOSHPUB2022107