Section 17. MINING WASTES
PILOT-PLANT COMPARISON OF VARIOUS MINING
SOLID WASTE RECLAMATION TECHNIQUES
M. Lynn Apel, Environmental Engineer
U.S. Environmental Protection Agency
Industrial Environmental Research Laboratory
Energy Pollution Control Division
Cincinnati, Ohio 45268
Janet Rickabaugh. Research Associate
Department of Civil and Environmental Engineering
University of Cincinnati
Cincinnati, Ohio 45221
It has been estimated that approximately 2.1 billion tonnes (2.3 billion tons) of solid
waste are generated annually by the mining industry, with mineral waste piles currently
covering over 800,000 hectares of land (approximately 2,000,000 acres) and representing
over 30% of the total waste produced in the United States 11 ].
Congress has passed several pieces of environmental legislation regulating the treatment
and disposal of solid wastes representing a danger to public health or the environment. Of
current concern is the 1976 Resource Conservation and Recovery Act (RCRA) and its
subsequent amendments. This legislation has provided the impetus to develop solid waste
disposal techniques that are not only practical and economically feasible but also utilize
recycle and reuse technologies whenever possible.
This study examined two approaches for treating the surface of a disposal area in order
to mitigate metal and acidity loads in the acid mine drainage leachate resulting from an
acidic mine waste. The first approach used digested sewage sludge, agricultural limestone,
and commercial fertilizer to treat the surface of a waste pile in order to neutralize the acidic
waste and resulting drainage and develop a plant growth supporting medium. In this case,
the treated surface may serve as an oxygen barrier and reduce further oxidation of the
Pyrite in the waste material. The second approach involved placing a cover soil layer over
the mine waste to achieve the same goal. In both cases the treated surface was planted with
vegetation.
The objectives of this study included determination of the physical and chemical quality
of leachate generated from test columns containing an acidic mine waste under various soil
amelioration and layering configurations, determination of the quantity of leachate produced relative to water input based on rainfall statistics of the geographical location under
study, and assessment of the vegetative uptake of potentially hazardous materials from
the mine waste.
For this study, a pyrite mine waste from the Contrary Creek, Virginia area was chosen.
This material was highly acidic and represented a worst-case study for control techniques.
Contrary Creek is located in east central Virginia approximately 65 kilometers (40.3 miles)
northwest of Richmond and 120 kilometers (74.4 miles) southwest of Washington, DC.
Contrary Creek is approximately 8 kilometers (5 miles) long and drains an 18 square kilometer area (7 square miles) which includes three abandoned pyrite (iron disulfide - FeS2)
mines and 17 hectares (42 acres) of pyritic tailings that have remained since mining ceased
in the early 1920s [21.
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