Laserfiche WebLink
<br />• properties will also depend on characteristics of the process <br />plant. Our analysis considered a range of properties for the coal <br />waste to allow for variations. Additional testing of the coal waste <br />~ ~ is recommended when coal processing is initiated to confirm the <br />~'~~~ ~ waste properties are within the ranges considered. Construction <br />phase testing is discussed in more detail in following sections. <br />~ The coal waste is derived from a long wall mining method and <br />consists primarily of low quality coal and shale fragments. The <br />results of laboratory testing on both the unprocessed and processed <br />~ coal are presented in Appendix B. The processed and unprocessed <br />waste are coarse-grained materials with little fines (less than 10 <br />• percent). For stability analysis the coal waste was modeled as a <br />cohesionless soil. Direct shear testing indicated peak friction <br />angles of 43 to 53 degrees at various densities and moisture <br />~ contents (fable B-1 ). Proctor, relative density and specific <br />gravity test results were used to estimate probable mo ist unit <br />weights of the coal waste. At 90 percent of maximum Proctor density <br />~ and near-optimum moisture content, moist unit weights of 95 to 111 <br />• <br />• <br />pcf were estimated for unprocessed and processed coal waste, <br />respectively. Properties for coal waste used in the stability <br />analysis were: <br />Friction Angle m -Normal Value 35 degrees, Lower Bound 30 degrees. <br />Cohesion C = 0 psf <br />Unit Weight -Normal Value 100 pcf, Lower bound 80 pcf. <br />10 <br />