Towards reducing the physical environmental impact of North American surface coal mines; a review of potential selective overburden handling techniques

Abstract

In North America, coal and lignite are presently extracted from natural materials by a variety of surface mining techniques that are largely dictated by factors such as coal thickness and attitude, overburden characteristics, and geological complexity of the deposit. Although a large variety of techniques are used, they are often similar within certain geographic regions, each being associated with a typical method of overburden handling and one or more major type(s) of physical environmental impact (topographic, stratigraphic and/or geohydrologic). While it is technically feasible to modify current routine overburden handling practice, or to introduce effective novel selective handling techniques in order to reduce subsequent environmental damage within each geographic region, economic factors do not always favour selective methods. Because of the possibility of increased stripping costs, the implementation of any selective overburden placement scheme requires site-specific appraisal of the profitability of the operation. In some situations, however, the use of selective techniques in place of conventional methods can actually be economically superior. The appropriate selective overburden placement schemes that can be applied in the different geographic regions are assessed in this review.