Mine Waste Disposal

Significant volumes of earth must be displaced to mine coal coal mines and the resulting rock waste can disrupt the environment. Furthermore, burning coal releases environmentally harmful chemical compounds into the air. 

Waste material from deep mines derives from the sinking of shafts, roadways, and ventilation tunnels, and extraction of the coal seam. This is then hauled to the surface and dumped locally. Previously, when coal was dug by hand, much of the waste was stored underground in voids. However, the implementation of modern mechanical techniques, particularly with the introduction of coal cutting machines on the coal faces, has dramatically increased the proportion of waste material. 

Another issue related to waste disposal arose because of the oxidation of pyrite that produces acidic compounds, which, with other toxic materials, can be leached into the local water supply. Simultaneously, heat produced from such chemical reactions led to spontaneous combustion of coal particles in the waste tips (Guney, 1968 McNay, 1971). The potential hazards from spontaneous combustion in the spoil heaps can be substantially reduced by controlled tipping, site selection, as well as compaction of waste. 

Surface mining has a greater adverse effect on the surroundings than underground mining operations. 

Area mining occurs on level ground, where workers use excavation equipment to dig a series of long parallel strips, or cuts, into the earth. The overburden is cleared from each cut, and the material (known as spoil) is stacked alongside the long trench. After the exposed coal is shoveled from the cut, workers dump the spoil back into the trench to help reclaim the mined area. 

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Hatch, J. and E. Hayes. "State-of-the-Art Remedial Action Technologies Used for the Sydney Mine Waste Disposal Site Cleanups," In Management of Uncontrolled Hazardous Waste Sites Proceedings, Washington, D.C., 1985, pp. 285. 

Unregulated mining waste disposal (salt mining in the Llobregat basin)... 

Fig. 4. Two contrasting spoil heaps in the Gardanne Coal Basin, Provence, France (a) Unrestored heap near Domaine de la Salle, showing largely bare spoil with characteristic development of scree and rills (cf. Nicolau 2002), with the only vegetation being a few self-seeding Mediterranean pines (b) Restored, thoroughly afforested spoil heap at Meyreuil, barely recognizable as a former mine waste disposal site.

The environmental implications of dedicating a lake to mine-waste disposal can be significant. Mining companies proposing subaqueous disposal in natural water bodies face regulatory hurdles, and in some jurisdictions, disposal of mine wastes in natural water bodies is not permitted. In addition, mine sites may be remote from water bodies that have the size or depth to accommodate the mass of mine wastes generated through... 

The level of natural versus man-made emissions to the environment are of a similar magnitude. SoH erosion is the major contributor of natural emissions with zinc mining, zinc production facHities, iron and steel production, corrosion of galvanized stmctures, coal and fuel combustion, waste disposal and incineration, and the use of zinc fertilizers and pesticides being the principal anthropogenic contributors. 

Sources of lead in dust and soil include lead that falls to the ground from the air, and weathering and chipping of lead-based paint from buildings and other structures. Lead in dust may also come from windblown soil. Disposal of lead in municipal and hazardous waste dump sites may also add lead to soil. Mining wastes that have been used for sandlots, driveways, and roadbeds can also be sources of lead. 

Al T.A., Blowes D.W., Jambor J.L., Scott J.D. 1994. The geochemistry of mine-waste pore water affected by the combined disposal of natrojarosite and base-metal sulfide tailings at Kidd Creek, Timmins, Ontario. Canadian Geotechnical Journal, 31, 502-512. 

Kunze, C., 2003, Handling, treatment and disposal of naturaUy occuring radioactive wastes (NORM) from mining and water treatment. In Hehenstreit, C., Kudelko, J., and Kulczycka, J. (Eds.) Mine Waste Management - Best AvaUahle Techniques, Krakow 2003, p. 186. 

Today, trends in waste disposal have changed markedly, as shown in the table on page 165. The single most common method of disposal is deepwell or underground injection, in which wastes are buried in abandoned mines, caves, or other underground structures, where, the assumption is, they will remain for very long periods. 

Banks, D. 1994. The abandonment of the Killingdal sulphide mine, Norway a saga of acid mine drainage and radioactive waste disposal. Mine Water and the Environment, 13, 35-48. 

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