An injection technique for in-situ remediation of abandoned underground coal mines

Conference · Thu Dec 31 04:00:00 EST 1998

OSTI ID:361690

Canty, G A; Everett, J W ^[1]

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1. Univ. of Oklahoma, Norman, OK (United States). Dept. of Civil Engineering and Environmental Science

Remediation of underground mines can prove to be a difficult task, given the physical constraints associated with introducing amendments to a subterranean environment. An acid mine abatement project involving in-situ chemical treatment method was conducted by the University of Oklahoma. The treatment method involved the injection of an alkaline coal combustion by-product (CCB) slurry into a flooded mine void (pH 4.4) to create a buffered zone. Injection of the CCB slurry was possible through the use of equipment developed by the petroleum industry for grouting recovery wells. This technology was selected because the CCB slurry could be injected under significant pressure and at a high rate. With higher pressure and rates of injection, a large quantity of slurry can be introduced into the mine within a limited amount of time. Theoretically, the high pressure and rate would improve dispersal of the slurry within the void. In addition, the high pressure is advantageous in fracturing or breaking-down obstructions to injection. During the injection process, a total of 418 tons of CCB was introduced within 15 hours. The mine did not refuse any of the material, and it is likely that a much larger mass could have been added. One injection well was drilled into a pillar of coal. Normally this would pose a problem when introducing a slurry; however, the coal pillar was easily fractured during the injection process. Currently, the pH of the mine discharge is above 6.5 and the alkalinity is approximately 100 mg/L as CACO{sub 3}.

• OSTI ID: 361690
• Report Number(s): CONF-9805185--
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ABANDONED SHAFTS
ACID MINE DRAINAGE
ASHES
COAL MINING
FLUID INJECTION
MITIGATION
PERFORMANCE
REMEDIAL ACTION
UNDERGROUND MINING
WASTE PRODUCT UTILIZATION