Mining, environmental concerns

Death Valley, California, has historically been a significant source of both colemanite and ulexite, but mining in the Death Valley National Monument has been forbidden as a result of environmental concerns. In 1986, the American Borate Co. ceased mining in Death Valley, but continues to market ore concentrate from inventory as well as borates and concentrates imported from Turkey. 

Bis(monofluoro)-triazine dyes, 9 473 Bismuth (Bi) 4 1-16. See also Bismuth alloys Bismuth compounds analysis, 4 10 barium alloys with, 3 344 catalyst poison, 5 257t economic aspects, 4 6-9 environmental concerns, 4 10-11 fabrication, 4 4-5 health and safety factors, 4 10-11 manufacture and processing, 4 3-6 mine and refinery production by country, 4 8t... 

Environmental concerns have led to an increased demand for low-sulfur coal, which is concentrated in the West. Also, surface mining, with its higher than average productivity, is much more prevalent in the West than in the East. Although more coal is mined east of the Mississippi than west, the share of western production has increased significantly since 1965, when production of western coal was only 27 million tons (5% of the total). By 1999, western production had increased to 571 million tons (52% of the total). In the period from 1990 to 1998, medium- and high-sulfur coal production decreased from 700 to 636 million tons. 

A principal environmental concern associated with mine wastes results from the oxidation of sulfide minerals within the waste materials and mine workings, and the transport and release of oxidation products. The principal sulfide minerals in mine wastes are pyrite and pyrrhotite, but others are susceptible to oxidation, releasing elements such as aluminum, arsenic, cadmium, cobalt, copper, mercury, nickel, lead, and zinc to the water flowing through the mine waste. 

One of the most serious environmental concerns associated with coal mining is the production of acid mine drainage. Coal mining exposes sulfur-bearing minerals to atmospheric oxygen and water. Pyrite is the principal source of acid production in coal spoils (Rose and Cravotta, 1998). Concerns associated with acidic coal-mine... 

The next major class of flame retardant additives that are nonhalogenated is the phosphorus-based flame retardants, but even these materials have some regulatory environmental concerns.Other nonhalogenated flame retardants that are not phosphorus-based exist, including mineral fillers (i.e., Al(OH)3, Mg(OH)2), expandable graphite, mela-mine, and polymer nanocomposites combined with other flame retardants.Each of these materials has its own advantages and disadvantages, and effectiveness in one polymer system often does not translate into another system. 

Thirty-four minor and trace elements are of potential environmental concern (n ). Sulfur is the element of major concern due to its abundance in flue gases from some coal-burning plants and its subsequent contribution to "acid rain." Sulfur as acidic ions of sulfate can also contribute to pollution of surface water and groundwater. Other elements of greatest concern are As, B, Cd, Pb, Hg, Mo, and Se. With the exception of B and Se, these elements are strongly associated with mineral matter in the coal and are concentrated in waste piles from coal preparation plants. If the waste disposal site is not constructed as a closed system, pollution of nearby groundwater is possible. Boron and Se may contribute to the pollution risk as they are associated with both mineral and organic components. On the other hand, certain coal-mine wastes have potential for recovery of valuable metals such as zinc and cadmium (18). 

Like many mining and refining operations there have been environmental concerns surrounding phosphate mining in Idaho. Until recently the most significant problems had been the air quality of calciner emissions, water quality surrounding waste piles, slight... 

The environmental concern about this element has arisen quite recently, since over half the cadmium ever produced has been refined in the last few decades (Nriagu, 1979). The main sources of Cd contamination in soils are metalliferous mining and smelting, heavy applications of sewage sludge, P-fertilizer and input from atmospheric deposition. 

Besides, Nanzhuang Coal Mine stored the drained methane and then utilized these gases for economic and environmental concerns, and these will be presented in the next section. 

The majority of the primary smelters responding tend to treat secondary materials. In conjunction with environmental concerns and the decreasing net lead mine output during the last ten years, which resulted in difficulties in sourcing adequate supplies of concentrates and led to temporarily high treatment charges, the use of secondary materials was intensively... 

More and more attention is being paid to the recycling of rare earth elements from industrial scrap in order to help secure the supply of these elements, mostly because of their limited occurrence in minable primary resources and also because of the environmental concerns associated with mining and separation operations. The chapter presents a comprehensive review of the... 

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