Overburden Chemistry: A Review and Update

Abstract

Surface mining in the western United States involves the identification and handling of unauitable overburden. The ~th~dologies inv~lved in-overburden characterizai:ioll•vary greatly Uong western 1tatea and are 1 Paper presented at the American Society for Surface Miniug and lleclaaation Annual Meetings.

Trace and Minor Elements in Coal

“…Boon et al (1987) noted that most western U.S. coal-mining states now require baseline information on several trace elements, especially selenium, boron, and molybdenum. The release of selenium from coal combustion wastes has caused significant environmental damage (extensive fish kills) at two sites in North Carolina and one in Texas (Shepard, 1987).…”

Environmental Aspects of Trace Elements in Coal

“…However, some sandstones hosting U roll-front type deposits may be very high in concentrations of elements associated with uranium (e.g., Se, Mo, V, As, Cu, and Pb) and reactive sulfide minerals (e.g., pyrite, marcasite, and arsenopyrite) (Boon et al, 1987). These properties may not be independent of each other.…”

“…Perhaps the philosophy Severson and Gough, 1981;Gough, 1984 (Boon et al, 1987). The requirements for sampling replaced overburden range greatly from state to state in the western United States.…”

“…Besides trace element spatial variability, uncertainties exist in proper sampling procedures, sample preparation and analytical methods, suitability criteria for overburden and the mixing and proper placement of unsuitable overburden (Boon et al, 1987). Adapting remote sensing technologies such as AVIRIS (Advanced Visible and Infra-red Imaging Spectrometry), conductivity, resistivity, or electromagnetic geophysical techniques, when correlated with trace-element composition, may become the most cost effective means of describing small-scale spatial variability of replaced overburden and mine soils .…”

“…Fisher, Jr. , pers. The only true measure of bioavailability is, of course, the uptake of trace elements by vegetation (Table 14.6); however, sampling of vegetation to determine chemical quality of cover-soil is usually only performed in the western USA if there is some revegetation failure (Boon et al, 1987). In general past studies have been disappointing because, as we have stated, reclaimed overburden materials are chemically, physically, and biologically much different than mature soils.…”