Water quality improvements resulting from FBC ash grouting of buried piles of pyritic materials on a surface coal mine
A 37 acre surface coal mine in Clinton County, Pennsylvania, was mined and reclaimed between 1974 and 1977. Buried pyrite-rich pit cleanings and tipple refuse were found to be producing severe acid mine drainage (AMD). The pyritic material is located in discrete piles or pods in the backfill. The pods and the resulting contaminant plumes were initially defined using geophysical techniques and confirmed by drilling. Isolating the pyritic material from water and oxygen will prevent AMD production. A grout, composed of fluidized bed combustion (FBC) ash and water, was used in two different approaches that attempted pyrite isolation. Pressure injecting grout directly into the buried pods to fill the void spaces within the pods and coat the pyritic materials with a cementitious layer was the first approach. In the second approach, pods that would not accept grout because of a clay matrix were capped with the grout to isolate the pyrite from percolating water. The grout was also used in certain areas to blanket or pave the pit floor to prevent dissolution of clays, which are a suspected primary source of high aluminum (Al) concentrations at this site. Monitoring wells have been sampled since 1990 to monitor changes in the water quality resulting from grouting efforts. Grouting occurred during the summers of 1992 and 1993. Statistically significant water quality improvements have been noted as a result of the grouting, although results are varied. Any water quality improvements resulting from the grouting are expected to be permanent because of the nature of the cementitious grout.
- OSTI ID:
- 588791
- Report Number(s):
- CONF-9605286-; TRN: 98:001296-0025
- Resource Relation:
- Conference: 13. annual meeting of the American Society for Surface Mining and Reclamation (ASSMR), Knoxville, TN (United States), 18-23 May 1996; Other Information: PBD: 1996; Related Information: Is Part Of Successes and failures: Applying research results to insure reclamation success; Daniels, W.L.; Burger, J.A.; Zipper, C.E. [Virginia Tech, Blacksburg, VA (United States). Depts. of Crop and Soil Environmental Sciences and Forestry] [eds.]; PB: 889 p.
- Country of Publication:
- United States
- Language:
- English
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