Respiratory diseases affect the structures and organs that are involved in breathing. These include the nose, throat, larynx, trachea, bronchi, and lungs. Miners may develop various occupationally-related respiratory diseases based on the materials they work with and how much exposure they have had to them.

Pneumoconiosis is a general term for diseases of the lungs caused by the inhalation of respirable-sized dusts. Respirable dust is defined as being less than 10 micrometers in diameter, and dust of this size is normally not visible. Airborne respirable dust that is inhaled by miners can be deposited in the lungs and cause damage to the lung tissue. In mining, the cutting, breaking, crushing, drilling, or grinding of coal, ore and surrounding rock produces airborne respirable dust. If sufficient dust is deposited in the lungs and lung damage occurs, a miner can develop pneumoconiosis. Although mild cases of pneumoconiosis may not produce any symptoms, there is a danger that the disease could progress to become disabling or fatal.

Coal Workers´ Pneumoconiosis (CWP), commonly called Black Lung, is a lung disease caused by inhaling excessive amounts of respirable coal mine dust. The likelihood of developing CWP increases with exposure to higher levels of respirable dust in the mine air and more time spent working in coal mining. Since 1970, NIOSH has offered periodic lung examinations to miners through the Coal Workers' X-Ray Surveillance Program. Seven percent of miners examined in the X-Ray Surveillance Program between 2005 and 2009 who had 25 or more years of experience, were diagnosed with pneumoconiosis.

Another form of pneumoconiosis that is of great concern to miners is silicosis, a disabling and often fatal lung disease caused by breathing respirable-sized dust that contains elevated levels of crystalline silica, or quartz. In mining, crystalline silica can often be found in rock strata associated with or surrounding the material being mined. Silica-containing dust is more toxic than coal dust. Of people who died of silicosis during the 1990s, mining machine operator was the occupation most frequently listed on the death certificate.

Other forms of pneumoconioses can be caused by inhaling dusts containing aluminum, antimony, barium, graphite, iron, kaolin, mica, and talc, among other dusts.

Once contracted, pneumoconioses (especially silicosis) cannot be cured, so it is critical to prevent the development of these diseases by reducing the respirable dust exposure of miners.

Miners may also develop chronic obstructive pulmonary disease (COPD) which is a progressive disease that limits the amount of air that can be moved into and out of the lungs. COPD can become a disabling condition.

The work in this topic area is supported by the NIOSH Mining Diesel Monitoring and Control and Dust Monitoring and Control programs. See the NIOSH Mining Products page for software, guides, training materials or other items related to this topic.

Benchmarking Longwall Dust Control Technology and Practices (PDF, 1003 KB, 2011)
The National Institute for Occupational Safety and Health (NIOSH) conducted a series of benchmark surveys at longwall operations across the country to identify current operating practices and the types of controls being used. Gravimetric and instantaneous dust sampling was completed to quantify the dust levels generated by major sources on the longwall section and to identify different control technologies in use today. Substantial reductions in dust levels were realized at sampling locations on the face when compared with ongwall surveys conducted in the 1990s. Results from the underground dust surveys and current longwall dust control technology and operating practices will be discussed.

Field Evaluation of Air-blocking Shelf for Dust Control on Blasthole Drills (PDF, 443 KB, 2011)
In previous studies, an air-blocking shelf has been shown to be successful in reducing respirable dust leakage from the drill shroud in a laboratory setting. Dust reductions of up to 81 percent were achieved with the shelf under operating conditions consisting of a 1.9:1 collector-to-bailing airflow ratio and a 5.1-cm gap between the shroud and ground. Recent research focused on evaluating the shelf on two actual operating blasthole drills, in much more severe environments. In the field, the shelf reduced dust levels in the areas surrounding one operating blasthole drill by 70 percent. Dust reductions measured in the immediate vicinity of the shroud were reduced by 66 percent at one mine and 81 percent at the other mine. These field tests confirm that the air-blocking shelf is useful for reducing respirable dust generation from blasthole drills.