Site Selection, Design, and Reclamation of the Winding Gulf Refuse Pile, Raleigh County, West Virginia

Abstract

The Winding Gulf refuse pile is an abandoned coal refuse facility which stores about 505,000 cubic yards of coal refuse. The pile was placed indiscriminately across a small stream valley as the Beckley coal seam was mined in the area from the 19209s to the 19509s. Since it blocks the natural drainage of a small watershed, this non-engineered structure has been categorized by the West Virginia Department of Natural Resources as being of “high hazard potential.” This has necessitated relocation of the refuse material. Field observations and subsurface drilling performed by the authors indicate the material to be fairly uniform in nature and composition. Results of a washability study indicate that about 50 percent of the pile material can be recovered as a salable product if the pile was reprocessed at a separation gravity of 1.6. The separated coal product would have a heating value of 13,500 BTU/lb. and an ash content of 9.5 percent. The refuse remaining after reprocessing would be disposed of at a new site. Engineering tests on the separated refuse show it to be a well to poorly graded sand and gravel with non-plastic fines. Laboratory densities range from 91 pcf to 115 pcf. Specific gravity ranges from 1.85 to 2.30. Direct shear test results show friction angles between 33 degrees and 42 degrees with little or no cohesion. Triaxial tests on two samples show effective friction angles of 19 degrees and 14 degrees and effective cohesion of 1,080 and 1,025 psf, respectively. Slake durability tests indicate high to very high resistance to slaking. Design of a new refuse facility at a newly selected site was accomplished using the “REAME” computer model developed by Huang. The “REAME” program analyzes embankment slopes for different conditions using the Simplified Bishop Method of Slices. Based on stability analyses, an embankment containing three lifts, each 50 ft high and placed at 2.5 to 1 slopes, has been recommended. The proposed embankment design also includes plans for diversion drainage.