Laserfiche WebLink
Christine Johnston, Kent Gorham, Jim Pendleton <br />• September 18, 199b <br />Page 4 <br />4. Assume, conservatively, that mining in the Apache Rocks permit revision area will <br />cause a 100 percent increase in the historic observed. mine inflow rate, jor an <br />additional 16 acre feet per year. <br />S. Historic minting experience at the West Elk Mine indicates (as stated on page 2.05- <br />176) that the annual mine inflow is predominantly a function of the amount of newly <br />opened mine workings and the magnitude and distribution of precipitation. Mine <br />water inflows in the futttre are expected to be similar to historic inflows and <br />substantially below. the estimates provided by previous analytical models. Despite the <br />fact that this is W~'E's basic fording with respect to groundwater inflows, for the <br />purposes of computing a cumulative annual water "loss." WWE is assuming that <br />groundwater inflows double, resulting in an increase groundwater inflow of 16 acre- <br />feet per year. <br />STOCK PONDS <br />• 1. There aze 13 stock ponds located in the Apache Rocks permit revision azea. <br />2. Potential impacts are limited to those ponds that are located above chain or barrier <br />pillars, or at the "margins" (outside edges) of the panels. By super-imposing the <br />stock pond locations on the map of the permit revision azea, there aze two stock <br />ponds, each with a volume of 0.5 acre-feet, that are potentially subject to a surface <br />crack. <br />3. The average annual "risk-based" stock pond loss can be calculated with Equation 3 as <br />follows: <br />(2 ponds) (0.5 AF/pond)(.002) = 0.002 AF =negligible <br /> <br />