Rock dust is a pulverized rock, usually

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

, sprayed on walls inside underground

coal mine Coal mining is the process of resource extraction, extracting coal from the ground or from a mine. Coal is valued for its Energy value of coal, energy content and since the 1880s has been widely used to Electricity generation, generate electr ...

s to prevent

coal dust explosion Coal dust is a fine- powdered form of coal which is created by the crushing, grinding, or pulverization of coal rock. Because of the brittle nature of coal, coal dust can be created by mining, transporting, or mechanically handling it. Grinding ...

s. The dust acts as a heat sink, keeps

coal dust Coal dust is a fine-powdered form of coal which is created by the crushing, grinding, or pulverizer, pulverization of coal rock. Because of the brittle nature of coal, coal dust can be created by mining, transporting, or mechanically handling it. ...

levels down, and also prevents the incidence of

black lung disease Black lung disease (BLD), also known as coal workers' pneumoconiosis, or simply black lung, is an occupational type of pneumoconiosis caused by long-term inhalation and deposition of coal dust in the lungs and the consequent lung tissue's react ...

. Rock dust has been used since the early 1900s, but technological improvements have occurred. U.S. federal regulations require that rock dust be applied in all underground coal mine areas to mitigate the propagation of a coal dust explosion. Before September 2010, U.S. federal regulation mandated that the nation's coal mines maintain a total incombustible content (TIC) of at least 65% in nonreturn entries and at least 80% in the return airways. In September 2010, the U.S.

Mine Safety and Health Administration The Mine Safety and Health Administration (MSHA) () is a small agency of the United States Department of Labor which administers the provisions of the Federal Mine Safety and Health Act of 1977 (Mine Act) to enforce compliance with mandatory sa ...

(MSHA) published an emergency temporary standard increasing the total incombustible requirement in intake airways to 80%, effective June 21, 2011. The 65% TIC requirement was based on an average particle size termed "mine-size dust," which was based on an average of representative samples collected from mines in the 1920s. To determine compliance with federal regulation, mine inspectors systematically collect dust samples from sections of underground coal mines and send the samples to the MSHA

National Air and Dust Laboratory National may refer to: Common uses * Nation or country ** Nationality – a ''national'' is a person who is subject to a nation, regardless of whether the person has full rights as a citizen Places in the United States * National, Maryland, ce ...

Mount Hope, West Virginia Mount Hope is a city in Fayette County, West Virginia, United States. The population was 1,125 at the 2020 census. History Early settlers came to Mount Hope to begin mining coal. Coal miners in Mount Hope continued to thrive for about 250 years ...

for analysis of incombustible content.

References

{{reflist Calcium minerals Coal mining