Conceptual Engineering Plan and Cost Analysis for Mine Void Stabilization Using One Hundred Percent Coal Combustion By-Product Grout (Using the Allegheny Business Center Site as a Model).

摘要

The AES Warrior Run Power Plant in Cumberland, Maryland generates about 400,000 tons of alkaline coal combustion byproducts (CCBs) per year that are currently being returned to the surface mine that provides coal to the power plant. Nearby, the Georges Creek Coal Basin is underlain by heavily mined coal seams that are subject to ongoing or future land subsidence. The potential for subsidence in the area adversely impacts re-development opportunities for such sites. To illustrate an alternative use of these CCBs, the Maryland Department of Natural Resources (DNR) Power Plant Research Program (PPRP) evaluated the costs to use these CCBs for mine restoration at a model site in the Georges Creek Basin. For this hypothetical project, PPRP illustrates an alternative use of this unique local material that is environmentally and economically beneficial to re-development opportunities for those lands potentially subject to subsidence. The underlying business presumption is that the re-development potential could be enhanced if the risk of subsidence is eliminated, or at least greatly reduced at a reasonable cost. The results of this optimization study can be translated to other sites or areas in the Mid-Atlantic Highlands, where abundant sources of CCBs are readily available. Accordingly, a cost optimization study was developed to evaluate the use of CCBs as an option for backfilling 150,000 cubic yards (yd3) of mine void space. The cost for CCB use is benchmarked against a more conventional geotechnical technology using low density cellular concrete (LDCC), also referred to herein as conventional grout. LDCC was selected as the conventional grout type for this study because of its low strength and low viscosity characteristics, and because it is a commonly selected grout type for underground void filling operations.