High-volume, high-value usage of flue gas desulfurization (FGD) by-products in underground mines: Phase 1 -- Laboratory investigations. Quarterly report, July--September 1995

Efforts primarily focused on Subtask 2.2, Chemical and Mineralogical Characterization and Subtask 4.3, Selection and Testing of Transport System. As part of Subtask 2.2, samples were collected from the Freeman United Crown Mine III FBC disposal facility representing a verity of ages and weathering. A laboratory scale transport system has been built at the CAER to evaluate the potential of pneumatic transport for flue gas desulfurization material (FGDM) emplacement and to provide essential data for the mine emplacement demonstration as part of the Subtask 4.3 effort. The system is modeled after shotcreting systems and has the advantage that the material can be remotely placed without the need for forms. The test program is focusing on determining the pneumatic conditions necessary to maximize the strength of the emplaced FGDM under anticipated mine curing conditions while minimizing dust formation. Work on Subtask 4.1, Mine Selection, also proceeded during the quarter. A new mine site, located in the south-central section of the Pikeville quadrangle, Pike County, Kentucky, was examined for the field study. The proposed fill site is in the Middle Pennsylvanian Breathitt Formation Middle Amburgy coal bed, a coal previously mined by Costain elsewhere on the property. Efforts on Subtask 4.2, Hydrologic Monitoring Plan, focused primarily on theoretical issues concerning the effects of the mining and backfill activity on the ground water and surface water due to uncertainties in the location of the final field site. There are three major concerns about the effects of the mining activity: changes in the ground water flow field, changes in ground water quality, and consequential induced changes on stream flow