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i <br />THE ALLEN MINE <br />This study was conducted at the Allen Mine, a deep mining operation <br />recovering metalurgical-grade bituminous coal. The mine is located 40 <br />{ miles west of Trinidad, in Las Animas County, Colorado and has been active <br />l in the removal of coal since 1951. This coal is interbedded in marine <br />shale and both are removed during the mining process. The two materials <br />are separated and the shale waste material, commonly called slack, is <br />placed in waste dumps near the mine mouth. <br />J Fifteen years of climatological data has been collected at North <br />Lake, 10 miles north of the mine site. The average annual precipitation <br />l between 1962 and 1976 was 51 cm. During the 3 years of this study preci- <br />pitation ranged from 34.3 cm in 1978 to 50.8 cm in 1919. <br />• - Soil analysis has shown that the waste material contains gravel <br />fragments greater than 2 mm which account for 38 to 69 percent of the <br />waste volume. The remaining volume has been classified in texture as a <br />sandy loam to clay loam. The organic matter content was 1.0 to 2.3 percent. <br />i <br />This value also reflects carbon contamination from the coal in the waste <br />material. The electrical conductivity ranged from 0.8 to 6.7 mmhos/cm and <br />the pH was 8.3 to 8.8. The sodium absorption ratio (SAR) ranged from 15 <br />to 38. The SAR, pH, and electrical conductivity values are all high enough <br />to potzntially inhibit Alan*_ grow*_h. <br />The nine is situated in the valley or the ~urgatcira -fiver. T;~z 'ard <br />adjacznt to the mine in the valley bottcm is in improved ?assure or me_dcws <br />uszd for hay production and livestock grazing. <br />13 <br />