Mine dust

Group, vapor/dust/mine Categories of approval for specific zones Type(s) of protection the equipment fulfills... 

Rhenium does not occur free in nature or as a compound in a distinct mineral species. It is, however, widely spread throughout the earth s crust to the extent of about 0.001 ppm. Commercial rhenium in the U.S. today is obtained from molybdenum roaster-flue dusts obtained from copper-sulfide ores mined in the vicinity of Miami, Arizona, and elsewhere in Arizona and Utah. 

Care must be taken in handling radon, as with other radioactive materials. The main hazard is from inhalation of the element and its solid daughters which are collected on dust in the air. Good ventilation should be provided where radium, thorium, or actinium is stored to prevent build-up of the element. Radon build-up is a health consideration in uranium mines. Recently radon build-up in homes has been a concern. Many deaths from lung cancer are caused by radon exposure. In the U.S. it is recommended that remedial action be taken if the air in homes exceeds 4 pCi/1. 

Coal-Mine Dusting. A steady market for pulverized limestone is ia dusting coal mines with a noncombustible mineral dust as a federally mandated mine safety requirement. Of aU mineral dusts, limestone is by far the most commonly used (60—75% 0.074 mm (200 mesh)). Consumption ia 1991 was... 

Dispersion staining is useful for rapid deterrnination of refractive index and dispersion. It is appHed most often, however, for needle-in-a-haystack detection of any particular substance in a mixture such as chrysotile in insulation, cocaine in dust samples, quartz in mine samples, or any particular mineral, eg, tourmaline, in a forensic soil sample. 

Before scmbbing procedures were estabUshed for copper ore, most of the rhenium was lost as the volatile (Re202). A small portion, perhaps 10%, was retained in flue dust, which was processed to give the metal. A commercial flotation (qv) process for the recovery of the molybdenite by-product is available that permits a high recovery of molybdenum and rhenium. This process is used at the Caridad copper mine in Mexico. 

Talc is considered a nuisance dust and subject to regulation in the workplace by both the Occupational Health and Safety Administration and the Mine Safety and Health Administration. Eight-hour exposure limits for talc dust are two milligrams of talc per cubic meter. 

The inorganic tin compound that has received the most study from a toxicological viewpoint is stannic oxide. Autopsies performed on workers in the tin mining and refining industry, who inhaled tin oxide dust for as long as 20 yr, disclosed no pulmonary fibrosis (57). Inhalation for long periods produces a benign, symptomless pneumoconiosis with no toxic systemic effects (58). 

Whereas an explosion from methane tends to be localized, it may start coal dust explosions resulting in more widespread injury and loss of life. AH coal breaking operations result in formation of fine coal particles some are controlled with water during the mining operation. Breakage associated with hauling disperses dust, and dust accumulations can be made safe by rockdusting. Powdered limestone is spread over the mine surfaces to cover the dust. 

The Eederal Coal Mine Health and Safety Act set standards for mine ventilation, roof support, coal dust concentrations levels, mine inspections, and equipment. As a part of this comprehensive act, miners must receive medical examinations at employer expense, and payments are made from the U.S. government to miners who caimot work because of black lung disease. 

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