Laserfiche WebLink
auv~ u~ nuvnw G LL Ji r 14 •a~0 ~ -7FITZ$Z7 3Fll\ ~CORO" <br />the mine is between 10'4 and 10'5 centimeters per second <br />(~/s) - <br />• Hedrock is homogenous and isotropic <br />• Each mine cut will be reclaimed prior to the next 5-year <br />phase of mine development. However, a final calculation <br />was performed to determine the maximum range oP pumpages <br />which would be required to dewater the entire mine pit <br />assuming no reclamation. <br />• Discharge to the open mine pits will occur from all <br />directions under a constant hydraulic gradient ranging <br />between o.06 and o. 1. This range in hydraulic gradient <br />was determined from preliminary 2-dimensional model runs <br />of the cone of influence perpendicular to the northern <br />most mine cut. <br />The following is a summary of projected mine dewatering rates <br />which incorporate the assumption listed above. Hydraulic <br />conductivity (K) and gradient (i) were varied to provide a <br />realistic range of dewatering rates. <br />SUMMARY OF PROJECTED DEWATERING RATES (GPM) <br />K= l x 10~, i= 0.1 K l x 10"5, i 0.06 <br />5 Years 208 12 <br />10 Yeara 138 19 <br />15 Years 164 10 <br />20 Years 170 13 <br />25 Years 177 11 <br />25 Years' 268 16 <br />Assuming No Reclamatioh <br />The above estimated dewatering rates indicate that pumping rates <br />required to meet dewatering objectives should never exceed 300 gpm <br />over the 25-year life of the mine. The above estimates are based <br />on limited results of packer testing performed by Fox and <br />Associates (1985) and Morrison-Knudsen Corporation (MK) (1991). It <br />was assumed that underlying bedrock formations (shale, sandstone <br />and limestone) are isotropic and homogenous. If the underlying <br />bedrock is found to be significantly fractured, dewatering rates <br />~~ J! 6 <br />2 <br />