Laserfiche WebLink
area just east of the plant and adjacent to Coal Creek ( See <br /> Exhibit II-B-7 ) . Coal refuse has been deposited at this <br /> site continuously since 1961 . It is estimated that the <br /> refuse pile now contains about 1 . 5 million cubic vards of <br /> refuse and its maximum height is approximately 130 feet <br /> Recent sitL- inspections at the refuse pile show no indica- <br /> tions of failure , or sloughing . *Mid-Continent has been <br /> developing s long range plan for expanding the coal refuse <br /> disposal site . The study methods , considerations and <br /> conclusions follow . <br /> The initial effort was the examination of the <br /> present refuse pile by the :Morrison Knudsen Industrial and <br /> Mining Engineering group to determine its physical character- <br /> istics stability , hydrological conditions and base geometry • See <br /> Appendix II-B-7 . <br /> From field observations in test pits and literature searches <br /> it was determined that the original pile was stable with the <br /> required minimur: factor of safety . It was also calculated <br /> that a 300 slope angle would be satisfactory for a pile <br /> depth of 350 feet and a 370 slope angle would be satisfac- <br /> tory for a depth of up to 300 feet . In each case the <br /> minimum safety factor from sloughing was about 1 . 5 . <br /> A field investigation program was initiated <br /> in June 1977 to develop additional and more reliable informa- <br /> tion . <br /> The program consisted of drilling , trenching , <br /> collecting samples , measuring in-sits material density and <br /> `J subsequent laboratory geotechnical testing of samples rro.m <br /> *See further explanation on next page <br /> ,. -71- <br />