Laserfiche WebLink
• II.l.a Assessment of Construction of Mine Entries and Coal <br />Mining <br /> Although the permeability of the F Seam and <br /> overlying strata is very low and the quantity of <br /> water stored in these units is also low, water from <br /> these strata will occasionally seep into the mine. <br /> The Mt. Gunnison No. 1 Mine MRP (p.2-352) estimates <br /> that the rate of seepage will increase as mining <br /> progresses to a maximum of about 45 gallons per <br /> minute (gpm) about five years after initiation of <br /> mining operations and that a steady-state rate of <br /> seepage will eventually be attained. This estimate <br />• was based on cautious assumptions so as not to <br /> underestimate the expected mine water inflows. The <br /> inflows were estimated using the theory of non- <br /> steady flow to a well of constant drawdown in an <br /> extensive aquifer (Jacob and Lohman, 1952). The <br /> estimates were carried out for assumptions .of <br /> confined and unconfined conditions. The other <br /> assumptions were that: <br /> 1. Significant hydrologic connection will occur <br /> with any overburden aquifers present up to 100 <br /> feet above the top of the F seam. Aquifers over <br /> 100 feet above the F seam are not likely to be <br /> affected. <br />• M <br />b <br />f <br />h <br /> em <br />er o <br />2. Aquifer coefficients of the Barren <br />t <br />e <br /> Mesaverde Formation have been determined from <br />-30- <br />