Silicosis, a debilitating and potentially deadly lung disease, develops through inhalation of excessive levels of respirable crystalline silica dust. In underground coal mines, continuous miner operators have historically been at a high risk of overexposure to silica, with over 25% of compliance dust samples exceeding the permissible exposure limit. Flooded-bed scrubbers are fan-powered dust collectors … Read more
Nitrate is normally present in waters associated with mining as a result of blasting activities using ammonium nitrate or dynamite. It may also be present in groundwater and surface water in agricultural areas from fertilizer use. Nitrate is also normally present in municipal and industrial waste streams after the aerobic degradation of ammonia. The concentration … Read more
Our approach is to let the variability in the samples dictate how many samples should be collected and analyzed, and then to quantify and defend the results by means of standard statistical methods. This approach is illustrated in Figures 1 through 4, in which a distribution of acid-base accounting (ABA) values is shown for increasing … Read more
High-pressure shrouded sprays were first tested on a bench to determine air-moving capability and dust collection efficiency. The bench-scale tests indicated that at 500 psi and above, the dust collection efficiency, when sampled downstream of a water eliminator, was about 99 pct for two types of nozzles. However, for the same water flow, the induced … Read more
The increasing demand for titanium minerals, especially rutile, has sparked interest in the abundant domestic titanium resources of the United States. Although 93 percent of the rutile used in this country is imported, there are porphyry copper deposits in the Western United States that constitute a very large potential rutile resource. Rutile is used to … Read more
Any critical evaluation of the potential for contamination of groundwater by leachates from mining wastes must include consideration of the waste quantities and locations, the physical and chemical characteristics of the waste, and the waste disposal practices. The primary types of solid wastes generated by mining activities include overburden and waste rock from surface mining, … Read more
As discussed previously, the primary types of solid wastes generated by the mining industry are overburden and waste rock from surface mining, waste rock from underground mining, bulk tailings from metal-ore and non-metal mineral beneficiation and milling processes and refuse from coal preparation-plant processes. The methods commonly employed for disposal of these wastes in each … Read more
Each year the mining industry generates tremendous quantities of solid wastes as a byproduct of the mining and concentration or preparation of valuable ores, minerals and coal. In addition, the quantities of these wastes generated on a yearly basis is increasing due to: increased production resulting from rising demand, the depletion of near surface high-grade … Read more
Under its mission to effect pollution abatement, the Bureau of Mines began intensified research seeking means for economically disposing of the large amounts of Florida phosphatic clay wastes and reclaiming the mined land. The clays, which are discharged from the processing plants at about 3 to 5 pct solids , have colloidal characteristics and are … Read more
In the past 25 years there has been a wide expansion of the use of cyanide heap leaching by the mining industry. This process allows profitable recovery of gold and silver from low-grade ore. Heap leach pads are constructed on slight drainage grades and lined with an impervious clay and/or geotextile. Ore is stacked and … Read more