Reclamation

Surface and underground mining of coal can disrupt the pre-mining environment. Vegetative cover must often be removed. Geologic and soil profiles can be overturned so that rich soils are now buried and leachable, lifeless rock is on top. After mining is complete, reclamation of the land is necessary. 

Periodic reclamation may occur at area strip mines, where reclamation activities may follow the advancing strip pit by a specified distance. Alternatively, as may occur with a large open pit, reclamation may have to be deferred to the end of the mining operations where the pit expands with time or is needed to provide space for production and mining support traffic. 

In mountainous areas (such as those in the Eastern United States), mountain top removal sites may be the only flat land, other than river flood plains, suitable for development of homes and town infrastructure. Whatever the intent, reclamation plans must be considered in advance of mining operations. While the real added cost of reclaiming mined land cannot be denied, it is often most cost effective to integrate reclamation into the mining. Where a mining company has not considered such factors as the need for topsoil or burial of salty or acid forming materials, the result has been sites that are difficult to reclaim. 

The choice of post-mining land use (including the type of land ownership) is often a significant factor in reclamation. Land leased from a farmer would often be reclaimed for agricultural use, while government held land in recent years has often been used for parks, recreation, or wildlife habitat. Surrounding land use should be considered since land may often be reclaimed to its former use or to the predominant land use in the immediate area. 

Efforts in recent years have been directed toward the use of recycled material in reclamation. Sewage sludge has been used to add organic material to substitute top soil (Bhumbla, 1992 Logan, 1992). The bacterial content of sewerage sludge is usually not a problem, provided that grazing and human exposure at the site is delayed for several weeks or months after treatment. 

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B. R. White, "Reclamation and Recycling of Propellants and Explosive," ia J TNN TF Safety and Environmental Protection Subcommittee Meeting, Monterey, Calif., May 1988. 

R. A. McKay,M Study of Selected Parameters in S olid Propellant Processing,]et Propulsion Lab, Pasadena, Calif., Aug. 1986 J. L. Brown and co-workers. Manufacturing Technologyfor SolidPropellantIngredients/Preparation Reclamation, Morton Thiokol, Inc., Brigham City, Utah, Apt. 1985 W. P. Sampson, Eow Cost Continuous Processing of Solid Rocket Propellant, Al-TR-90-008, Astronautics Laboiatoiy/TSTR, Edwards AEB, Oct. 1990. 

J. L. Blown and co-workeis. Manufacturing Technologyfor SolidPropellant Ingredients/Preparation Reclamation, Moiton Thiokol, Inc., Brigham City, Utah,... 

L. W. Poultei and co-workeis, S olid Propellant Ingredient Reclamation, CPIA Pubhcation 556, CPIA, Johns Hopkins Urdveisity, Lauiel, Md., Oct. 1990, p. 107. 

Removing suspended inorganic material from waste streams generated in the beneficiation of ores or nonmetalHc minerals, to form a concentrated slurry that can be used for reclamation of mined out areas or other uses and a clarified water that can be discharged or recycled. 

E. A. Nephew, Suface Mining andEand Reclamation in Germany, Oak Ridge National Laboratory Rpt. ORNL-NSE-EP-16, Oak Ridge, Term., 1972. 

Material Control. Production forecasting, scheduling, direct and iadirect material procurement, purchasiag, shipping and receiving, storerooms, storage, surplus equipment, and reclamation of materials are iacluded. 

E. Jackson, MydrometallurgicalExtraction and Reclamation, Ellis Horwood Ltd., Chichester, U.K., 1986. 

A conservative estimate of the total value of the products from the mineral industry is ca 3.9 trillion ia terms of 1992 dollars (4). This estimate does not include the value of products derived from secondary sources such as recycling (qv) or reclamation. Secondary recovery is significant for certain commodities. For example, in 1992 ca 30% of the world steel (qv) production, 46% of the world refined lead output, 15% of the world refined copper (qv) production, and ca 30% of the aluminum (see Aluminumand ALUMINUM alloys) output from the Western world were clearly identified as being derived from scrap. The value of the world mineral commodity export trade in 1992 was ca 616,698 million ia 1992 dollars. This accounted for ca 18% of all commodities exported (4). 

A. E. Zarubiu, Reclamation and Fdevelopment of Walnut and Fruit Forests in Southern Kdrghic a, Israel Program for Scientific Translations, Jemsalem, 1968,... 

The western phosphates are sedimentary deposits in adjoining areas of Wyoming, Idaho, and Utah derived from a former inland sea. They consist of layers of limestone, phosphate, and chert, now budded and faulted so they are rarely horizontal. The phosphate ore is strip-mined using large earth-moving equipment such as shovels, scrappers, dump tmcks, and bulldozers to mine the overburden and phosphate ore. Mining ratios of overburden to metric ton of recovered ore are from 1—3 m /1 (2—4 yd /short ton). The typical mining practice is to remove ore and overburden from a pit in discrete layers (Lifts) of 10—20 m in depth. Overburden from the pit is back-hauled to a previously mined pit. Extensive land reclamation practices are later carried out to return the mine areas to natural states. 

Commercially, a small amount of the 4,4 -MDA is isolated by distillation from PMDA. Depending on the process employed, the removal of MDA can be partial (as is done with the isocyanates) or total. Partial removal of MDA gives some processiag latitude but yields of 4,4 -MDA are reduced. Distillation residues from PMDA manufacture that contain less than 1% MDA pose a disposal problem. Processes for the regeneration of MDA by heating these residues ia the presence of aniline and an acid catalyst have been patented (33—35). Waste disposal of PMDA is expensive and reclamation processes could become commercially viable. The versatility of the isocyanate process, however, can be used to avoid the formation of low MDA content distillation residues. 

The widespread availabiHty of electrical energy completely transformed modem society and enabled a host of breakthroughs in manufacturing, medical science, communications, constmction, education, and transportation. Centralized fossil fuel-powered, steam-turbine-based power plants remain the dominant means of electricity production. However, hydropower faciHties such as the 1900-MW Hoover Dam Power Project located on the Arizona—Nevada border, commissioned by the U.S. Bureau of Reclamation during the 1930s, have also made significant contributions. 

Preparation of Collected Materials. The actual amount of recovered MSW that can be recycled to meet buyers quaUty specifications is highly dependent upon how the material is collected and processed. There are primarily three methods available to collect MSW for recycling mixed waste, waste with commingled recyclables, or waste with separated recyclables. Which method of collection is chosen, in turn, determines the amount of preparation that is needed prior to reclamation and reuse. 

Much of the technology used in the reclamation of metals from metal-bearing wastes was developed by the mining iadustries. The primary means of recycling metal from metal and alloyed scrap is via pyrometaHurgy (see Metallurgy). 

Recovered copper in electronic scrap (old) is small in comparison representing about 14,000 t/yr of copper from 68,000 t/yr of waste (25). Electronic scrap accounts for iron (27,000 t), tin (14,000 t), nickel, lead, and aluminum (6,800 t each), and zinc (3,500 t). Precious metal value, which is the primary economic reason for the reclamation of electronic waste, accounts for 345 t of gold, twice that in silver, and some palladium. 

In spite of these efforts, significant quantities of metal-bearing wastes, ha2ardous or not, continue to be earmarked for disposal rather than reclamation. There are several reasons. Often the wastes are mixed from several process streams, contain relatively low concentrations of many recoverable metals, and may contain high concentrations of water, silicates, and secondary metals, such as calcium and iron. 

American Tire Reclamation, Inc. (Detroit, Michigan) plans to constmct a commercial-size plant to supply a refined version of carbon black and oil produced by pyrolysis of tires. The pyrolysis product improves aging and reduces mtting when added to asphalt (qv) (28). 

Interior Department Interior land management, fish and wildlife. Geological Survey, mines, surface mining and reclamation... 

Sedimentation equipment can be divided into batch-operated settling tanks and continuously operated thickeners or clarifiers. The operation of the former is simple. Whereas use has diminished, these are employed when small quantities of Hquids are to be treated, for example in the cleaning and reclamation of lubricating oil (see Recycling, oil). Most sedimentation processes are operated in continuous units. 

Pretreatment and Reclamation of Dusts, Sludges, and Scales in SteelPlants, Conference Proceedings, McMaster University, Hamilton, Ont., Canada, 1993. 

Health and safety factors in in situ operations are associated with high temperature, high pressure steam, or high pressure air. Environmental considerations relate to air and water quaUty and surface reclamation. In some environmentally sensitive areas such as the oil sands deposits in Utah, environmental considerations may make development unfeasible. 

In the United States, the largest concentration of atmospheric vanadium occurs over Eastern seaboard cities where residual fuels of high vanadium content from Venezuela are burned ia utility boilers. Coal ash ia the atmosphere also coataias vanadium (36). Ambient air samples from New York and Boston contain as much as 600—1300 ng V/m, whereas air samples from Los Angeles and Honolulu contained 1—12 ng V/m. Adverse pubHc health effects attributable to vanadium ia the ambieat air have aot beea deteroiiaed. lacreased emphasis by iadustry oa controlling all plant emissions may have resulted ia more internal reclamation and recycle of vanadium catalysts. An apparent drop ia consumption of vanadium chemicals ia the United States since 1974 may be attributed, in part, to such reclamation activities. 

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