Dust, Mine

mineral particles of a useful mineral and/or gangue that are suspended in a mine atmosphere or that have settled in mining excavations. A principal characteristic of the dust is particle size. On particle size depend the rate of reaction with oxygen, adsorbability and electrical properties of the dust, as well as its biological activity.

Mine dust is a major occupational hazard. Some types of dust (coal, schist, sulfur, sulfide) can also, under certain conditions, form an explosive mixture with air. Dust is dangerous because it can damage the lungs and living tissue by coarse-fiber connective tissue; it can also lead to diseases of the upper respiratory tracts, eyes, and skin. Moreover, the dust of minerals containing lead, manganese, arsenic, and other elements is toxic, and uranium and thorium dusts are radioactive.

Dust content in the air is controlled in two ways. On the one hand, dust can be removed from the air through precipitation of dust in filters with determination of the dust’s weight content or through precipitation of the dust on screens with determination of particle size and number of particles. Alternately, photoelectric, electrometric, optical, and radiation methods can be used without extracting the dust from the air; these methods involve determination of the weight content of the dust and the number of dust particles and their size.

The disease pneumoconiosis is mainly associated with the weight of the dust that is inhaled and not with the number of particles; in the USSR, therefore, concentrations of dust in the air are determined by weight. Permissible concentrations in the air of a working zone (up to 2 m above the floor of the excavation) range from 1 to 10 mg/m³; for toxic dust, the range is 0.01 to 6 mg/m³.