Surface mining

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

Because the ore quaUty is variable, large open-pit mining areas are first identified by general exploration specific mining strips are later identified by further exploration and testing. Surface mining methods are used. The overburden is drilled, blasted, and removed, and the waste from a given strip is dumped into a previously worked-out strip. After removal of the overburden, the exposed caUche is drilled, blasted, and loaded into 80-metric ton tmcks that dehver the ore to a transfer rail station for transportation to the plants. 

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

Brazil. Brazil has two principal crystalline flake mines, a smaller one at Itapecerica and a larger one at Pedra Azul, both in Minas Gerais State. Both mines are owned by Nacional de Grafite Ltd. The ore at Itapecerica averages 20% carbon and is surface mined from a number of pockets spread over an area of ca 129.5 km (50 square miles). The ore at Pedra Azul averages 7% carbon, is larger flaked than the other, and is disserninated in heavily weathered gneissic rock. 

The weighted average values fob underground and surface mines decreased from 28.24/1 iu 1984 to 23.99/t iu 1990 (2). Underground mine prices decreased from 36.66/t to 31.51/t, whereas surface mine prices dropped from 22.70/t to 18.72/t. 

The Department of the Interior is the home of the Bureau of Land Management, the Minerals Management Service, the Office of Surface Mining Reclamation and Enforcement, and the U.S Geological Suiwey (USGS). 

Coal from underground mines is assessed an excise tax of 1.10 per ton, and coal from surface mines is assessed a tax of 0.55 per ton, but in each case, a constraint is added that states that the tax cannot exceed 4.4 percent of the sales price. The receipts from these taxes are allocated to the Black Lung Disability Trust Fund. Monies from this trust fund are used to pay for health benefits to coal miners. 

Installations underground in mines and self-propelled mobile surface mining machinery and its attendant electrical trailing cable. 

Underground mining/cost tonne ore-surface mining cost/ton ore... 

Waste removal cost/tonne of waste in surface mining... 

Mining overburden. After an area of a surface mine has been depleted, it is common practice to return to the mine the earth and rocks (overburden) that were removed to gain access to ore deposits. When the material is returned to the mine site, it is not a hazardous waste under RCRA. 

Figure 4. Comparison of GHG emissions from shale gas and conventional natural gas with low and high estimates of fugitive methane emissions, surface-mined coal, deep-mined coal, and diesel oil time horizon equal to 100 years [27]...

Calcium oxide can be produced from extensive heating of limestone. Primarily composed of calcium carbonate, limestone is extracted from both underground and surface mines and heated to temperatures exceeding 180°F to convert the calcium carbonate into calcium oxide. This thermal decomposition reaction also generates carbon dioxide gas. 

Davison, J., The lambda process - for desulfurization of slurry coal fines prior to combustion, in Eighth Annual Surface Mine Drainage Task Force Symposium. 1987. Morgantown, West Virginia, April 7-8. 

Nuclear power plants are based on uranium mined in surface mines, or by in situ leaching. 

Heinold, D. Smith, D. Finding the weak links. Environ. Protection 2003, 14 (2), 56-65. Munshower, F.F. Microelements and their role in surface mine planning. In Coal Development Collected Papers, Volume IT, Coal Development Workshops in Grand Junction, Colorado and Casper, Wyoming, Bureau of Land Management, July 1983. 

Having noted these technical matters, it should, however, also be observed that the operational flexibility of available processing equipment usually quite subordinates them to coal costs (which represent between 25 and kO per cent of the plant gate costs of the product). Most future conversion plants are therefore likely to use lignites and subbituminous coals which, in Canada as in many other countries, are abundantly available at low cost through surface-mining. 

Resolution of major technical problems of current surface mining technology. 

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