Limestone additions to affect changes in loading to remediate acid mine drainage
- Univ. of South Carolina, Columbia, SC (United States)
All things being equal, the acid potential of pyritiferrous rock naturally outstrips the rate of alkaline production due to the differences in solubilities and rates of pyrite reaction and bicarbonate dissolution. Thus, mixtures of acid and alkaline waters produced by the two chemical systems usually result in net acid conditions when the blending of these two water types takes place. The study area watershed was indirectly impacted by mineral mining when pyrite-rich tailings were transported downstream and deposited. The acidity produced by the tailings deposits varied from 50 to 200 mg/l and, based on detailed field traverses, the area of the deposits was approximately 1672 m{sup 2}. The strategy was to generate at least four times more flow through alkaline material than the acid horizons, thereby, adjusting alkaline loads to neutralize the acid drainage. A blanket application of imported limestone, 8 cm thick and covering approximately 6690 m{sup 2} was placed during June and July, 1995, near the headwaters and removed from the acid producing areas. To date we have seen the acidity levels reduced to about 45 mg/l, As designed, the critical placement of the limestone blanket is intended to affect the quality of (1) run-off, (2) near surface interflow and (3) groundwater. The effects of acid rain, coupled with the time necessary for impacts to take place on the groundwater and vadose zones, suggests that at this time, only the run-off component is reporting to the stream and that more time is needed for the flow path to become sufficiently alkaline and effect the drainage quality.
- OSTI ID:
- 588860
- Report Number(s):
- CONF-9605286-; TRN: 98:001296-0061
- 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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