Mining operations

Molybdenum is also recovered as a by-product of copper and tungsten mining operations. The metal is prepared from the powder made by the hydrogen reduction of purified molybdic trioxide or ammonium molybdate. 

Open-arc furnaces Open-celled foam Open-circuit potential Open-mold processes Open-pit mining Operating line... 

There are, however, a variety of other sources of methane that have been considered for fuel supply. Eor example, methane present in coal (qv) deposits and formed during mining operations can form explosive mixtures known as fire damp. In Western Europe, some methane has been recovered by suction from bore holes drilled in coal beds and the U.S. Bureau of Mines has tested the economic practicaUty of such a system. Removal of methane prior to mining the coal would reduce explosion ha2ards associated with coal removal. As much as 11.3 x 10 (400 trillion (10 ) cubic feet or 400 TCE) of... 

Minerals and Metals. HCl is consumed in many mining operations for ore treatment, extraction, separation, purification, and water treatment (see Mineral recovery and processing). Significant quantities are also used in the recovery ofmolybdenum (see Molybdenum and molybdenum alloys) and gold (see Gold and gold compounds). This market consumed about 36 thousand metric tons in 1993. 

Mica mining is subjected to local, state, and federal laws. The Mining, Safety and Health Administration (MSHA) regularly monitors mica mining operations for safety violations. 

In a general sense, however, the term heavy oil is often appHed to a petroleum that has a gravity <20° API. The term heavy oil has also been arbitrarily used to describe both the heavy oil that requires thermal stimulation for recovery from the reservoir and the bitumen in bituminous sand (also known as tar sand or oil sand) formations, from which the heavy bituminous material is recovered by a mining operation. Extra heavy oil is the subcategory of petroleum that occurs in the near-soHd state and is incapable of free flow under ambient conditions. The bitumen from tar sand deposits is often classified as an extra heavy oil. 

Table 7. Environmental Impact of Surface Mining Operations...

Montan Wax. Montan wax [8002-53-7] is derived by solvent extraction of lignite (qv). The earliest production on a commercial scale was in Germany during the latter half of the nineteenth century, and Germany continues to supply the majority of the world s production of montan wax. Montan wax production at Amsdorf is part of a massive coal-mining operation from a continuous vein and raw material is expected to last for decades. Montan wax is also produced in the United States. Imports of montan wax into the United States for the years 1990—1995 are Hsted in Table 1. Germany suppHes over 80% of the montan wax imported into the United States (3). 

The choice of a particular mining method depends on a number of parameters, typically the physical properties of the host matrix, the fiber content of the ore, the amount of sterile materials, the presence of contaminants, and the extent of potential fiber degradation during the various mining operations (33). However, most of the asbestos mining operations are of the open pit type, using bench drilling techniques. 

Mined bismuth in China is a by-product of tungsten mining operations, but most of the bismuth produced in China comes from bismuth concentrates. 

Fig. 2. Typical solution mining operation in a salt dome (9).

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. 

Keep in mind rail tariff breaks for numbers of cars in a string so that the ability to handle the required numbers can be provided. If the operation is large enough, as for large coal mining operations, unit trains (100 cars) are used. 

Three years ago, a fire in a large mining operation resulted in tens of millions of dollars in equipment damage and a half-billion dollar loss from months of lost production. 

Each of four teams for each mining operation consisting of a risk analyst and engineers and o 5erators performed the FRR. The risk analyst provided the FRR expertise and directed the analysis of the operation facility engineers and operators provided operational knowledge and estimated the likelihood of equipment failures and their impact on facility operations. 

Wliile some problems still exist, there is no question that coal mining operations are more efficient and safer for workers and leave less of an environmental footprint than operations several generations ago. As society s demand for energy from coal continues to increase and as coal s price declines (between 1978 and 1996 U.S. mine mouth prices fell from 47,118 to 18..S11 per ton in constant 1996 dollars), there is certain to be even gi eater efforts to limit the environmental impact of mining operations. 

Air and natural gas have also been used as drilling fluids in slim-hole-drilling mining operations, special large-diameter boreholes for nuclear weapons tests, and, more recently, in geothermal drilling operations. 

Effect of Moisture on Explosives Expls are the only energetic materials which can exist in useable form as a w slurry. These materials do not meet Mil specifications, however, they are commercially available and are used as gels in mining operations (Refs 35, 36, 43 44)... 

However, the seriousness of the problem, and its underlying causes, have only relatively recently been addressed by the mining industry (Ripley et al., 1996). As a consequence, many mining operations conducted before the 1980s were not managed to control the deleterious effects of acid drainage. 

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