Mining Topic: Respiratory Diseases
What is the health and safety problem?
Miners are at risk of developing lung diseases called pneumoconioses because of their regular exposure to airborne dust, and miners who are exposed to exhaust from diesel engines have an increased risk of dying from lung cancer.
The two main pneumoconioses (meaning dusty lung) that affect miners are:
CWP is associated with coal mining, but silicosis can affect workers in many types of mines and quarries, including coal mines.
Other respiratory diseases, such as chronic obstructive pulmonary disease (COPD), may also occur in miners separately from, or in addition to pneumoconiosis.
Pneumoconioses can cause impairment, disability and premature death. Medical treatment is not effective in advanced cases of these diseases, so preventing them – through controlling respirable dust exposure – is essential.
Exhaust from diesel engines has the potential to produce symptoms typical of asthma, and diesel exhaust exposure may contribute to other respiratory symptoms such as increased cough and phlegm. Additionally, miners with five or more years mining experience have an increased chance of dying from lung cancer.
What is the extent of the problem?
In 2010, CWP was the cause or a contributing factor in the death of 486 people. More than $45 billion dollars in federal compensation benefits have been paid to miners with CWP since 1968.
After a long period of decline, an increase in CWP has recently been seen in some areas of the country. A nationwide pneumoconiosis surveillance program administered by the National Institute for Occupational Safety and Health’s (NIOSH) Division of Respiratory Disease Studies identified CWP in 2% of underground coal miners examined during 2007-2011. A newly published report shows that 2% of examined surface coal mine workers—most of whom had never worked in underground mines—had CWP.
The recently published Diesel Exhaust in Miners Study of over 12,000 miners showed a significant increased risk of dying from lung cancer among miners who had ever worked underground. This risk increased as the miners’ exposure to respirable elemental carbon – representing diesel exhaust – increased.
How is OMSHR addressing the problem?
Reducing miners’ exposure to airborne dust directly reduces their risk of developing dust-related respiratory disease.
OMSHR has active programs working to reduce dust exposure to coal miners operating longwall and continuous mining equipment. OMSHR is also investigating how to reduce dust exposure to miners in all commodities who are mobile workers (they don’t have a fixed work position), or who perform work:
- with exploratory and blasthole drills,
- with other surface mining equipment,
- with mills and processing equipment, or
- in operating cabs and rooms.
OMSHR is also assessing the application and performance of engineering controls to reduce diesel exhaust ‘at the tail pipe’ and in areas where miners perform their work.
Finally, OMSHR is continuing work to develop and improve monitors that will provide on-shift information about concentrations of airborne agents so that operators and miners can take steps to quickly correct conditions that could lead to excessive exposures. A summary of OMSHR’s current efforts related to monitoring exposure to dust and toxic substances can be found at: http://www.cdc.gov/niosh/mining/topics/monitoringdust.html.
What are the significant findings?
OMSHR has published resources for the mining industry to assist their effort to control dust and diesel exposure. These include Best Practices for Dust Control in Coal Mining, Best Practices for Dust Control in Metal/Nonmetal Mining, Dust Control Handbook for Industrial Minerals Mining and Processing, and Diesel Aerosols and Gases in Underground Mines: Guide to Exposure Assessment and Control.
OMSHR research has produced a continuous personal dust monitor that can provide an accurate measurement of airborne respirable dust at the end of a mine workers’ work shift, and provides on-shift information that the worker can use to reduce his or her exposure. This instrument has been approved for use as a coal mine dust personal sampler, and is commercially available. Recent MSHA rulemaking specifies this instrument be used to measure dust exposure in certain coal mining operations.
OMSHR has also developed a mobile video exposure monitoring method and software application (Helmet-Cam) that combines real-time exposure data with concurrently recorded point-of-view video to identify exposure sources for mobile workers.
An instrument to monitor personal exposure to diesel exhaust particulate has been developed and demonstrated by OMSHR researchers. This instrument is commercially available.
What are the next steps?
OMSHR is currently evaluating potential dust control technologies such as tailgate spray manifolds on the longwall shearer, improved water sprays on longwall shields, stand-alone dust collectors on continuous mining sections, maintaining the dust control effectiveness of equipment cabs, and the application of optical remote sensing technology to monitor the source and movement of dust over extended areas.
OMSHR has also undertaken development of a methodology that would provide information about a worker’s exposure to respirable silica (quartz) at the end of the work shift. If this approach is validated, the delay in receipt of laboratory results would be eliminated. Removing this delay would allow the employer to more rapidly implement enhanced exposure controls, reducing the risk of silicosis among the exposed miners.
Noteworthy Publications & Products
- A New Leak Test Method for Enclosed Cab Filtration Systems (2012-05)
A new test method has been developed by the National Institute for Occupational Safety and Health (NIOSH) and Clean Air Filter (CAF) for quantifying the outside air leakage into environmental cab filtration systems.
- Best Practices for Dust Control in Coal Mining (2010-01)
This handbook was developed to identify available engineering controls that can help the industry reduce worker exposure to respirable coal and silica dust.
- Best Practices for Dust Control in Metal/Nonmetal Mining (2010-05)
This handbook was developed to identify available engineering controls that can assist underground and surface metal/nonmetal mining operations in reducing worker exposure to respirable silica dust.
- Diesel Aerosols and Gases in Underground Mines: Guide to Exposure Assessment and Control (2011-10)
A comprehensive guide to establish a program to curtail diesel particulate matter emissions, control pollutants after release in an underground mine environment and reduce exposures using administrative controls.
- Dust Control Handbook for Industrial Minerals Mining and Processing (2012-01)
Mined ore undergoes crushing, grinding, cleaning, drying, and product sizing as it is processed, generating harmful dust. This handbook reviews technologies for lowering dust levels below the permissible or recommended occupational exposure limits.
- EVADE Software (2014-08)
EVADE (Enhanced Video Analysis of Dust Exposures) is a software program that is designed for analyzing dust exposure in the mining environment through the simultaneous use of video and real-time dust concentration data.
- Field Assessment of Enclosed Cab Filtration System Performance Using Particle Counting Measurements (2013-09)
This article describes a study where a two-instrument particle counting method was used to examine a new cab filtration system design for underground industrial minerals equipment.
- Handbook for Dust Control in Mining (2003-06)
This handbook describes effective methods for the control of mineral dusts in mines and tunnels. It assumes the reader is familiar with mining. The first chapter deals solely with dust control methods, regardless of the application. It is a brief tutori...
- Laboratory and Field Performance of a Continuously Measuring Personal Respirable Dust Monitor (2006-09)
This report includes the theory of operation, description, and the performance of the Personal Dust Monitor (PDM) compared to gravimetric-based reference dust sampling methods and laboratory verification of the instruments accuracy.
- Reducing Dust Inside Enclosed Cabs (2009-10)
This study Identifies a number of significant factors that determine how effective an enclosed cab will be at protecting a worker.