Effectiveness of Lime Kiln Flue Dust in Preventing Acid Mine Drainage at the Kauffman Surface Coal Mine, Clearfield County, Pennsylvania

Abstract

A careful test of alkaline addition combined with special handling has been performed during mining of 27 acres of coal overlain by slightly to moderately pyritic overburden at the Kauffman Mine. Overburden holes indicate alkaline deficiencies of up to 1090 tons CaCO{sub 3}/acre. Sulfur contents for 1- to 3-foot intervals average 0.26%S and range up to 4.4%. An adjacent min produces severe AMD. Lime kiln flue dust, a waste product, was added in amounts adequate to neutralize maximum potential acidity. High-S zones were special-handled into compacted pods up to 2 ft. thick and covered by about 30% of the total lime requirement. About half the lime was spread on the surface prior to blasting and mixed during subsequent handling; the remaining lime was spread on the pit floor and beneath the topsoil. Over the period up to 1.5 years after mining, water in backfill and monitoring wells has pH of 6 to 7, alkalinity exceeding acidity, and generally low Fe, Al and Mn, indicating that procedure is a success. However, concurrent experiments with 400-ton test cells indicate that prompt addition of lime, and compaction of the material may be crucial for successful results.