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~~~~~~~ <br />C~ <br />APPENDIX II-B-1 <br />FACTORS WHICH DETERMINE THE MINE PLAN, <br />RATE AND PROGRESS OF PRODUCTION. <br />Production and actual recovery of coal reserves depends upon significant factors <br />which are largely beyond the control of the operator. These include (1) Geologic <br />Factors; and (2) Market Factors. <br />DEC ~ 197 <br />IV~IRIEI~ ~t~~~ <br />(DECLAMATION 171~/ISION <br />• <br />1. Geologic Factors. <br />The extreme depth of cover above the mining operations at Coal Basin is a <br />significant determinant of the rate and ratio of production, and requires constant <br />adaptation of the mine plan in response to the actual geologic conditions <br />encountered as mining progresses. <br />Mining methods, design of the mines, productivity and rate of progress are <br />substantially determined by geologic factors, and these factors are dynamic and <br />difficult to predict. At the same time, these factors must be dealt with as they occur. <br />Intense faulting, dikes and igneous intrusions characterize the geology of Coal <br />Basin and, because they are found in both of the coal seams being mined, prove <br />highly disruptive to the progression of mining. Roof control problems, stress zones, <br />and accompanying change in the pitch of the coal bed are commonly associated <br />with such zones. Mine plans, on occasion, must be changed to accomodate such <br />occurences. <br />For example: <br />- Longwall 102 encountered an igneous dike in <br />September of 1985. The dike crossed the face <br />diagonally from east-southeast to west-northwest, <br />and averaged.2 to 4 feet in thickness. <br />- Two dikes 8 - 9 and 4 - 6 feet thick were <br />encountered near the lower end of the Longwall 103 <br />startline entries in later 1985. The thicker dike <br />crossed the longwall panel itself, and had to be cut <br />during the first several weeks of operation. These <br />1 <br /> <br />W <br />.. .~ ....::.. __~. ,~ t Sys': _ _.. - _. _ ..._ ..~.~.-_. _... .:bjrf -'?~~~ u J <br />_..._~ d~- r ~ _ <br />