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_.. <br />~ ~ DESCRIPTIOiI OF THE EXISTING Ef;V[ROiJf1EtIT <br />CLIMATE <br />Rr <br />The climate ~ the Edna piine is typical of semi-arid steppe regions ~,•ith more than half <br />of the annual precipitation, 16 inches, faliiny as snow. The temperatures are cool, <br />61° average mean for August, to cold, 18° average mean for February. Although the <br />regional winds are from the f•Jest, local topography effects both precipitation and winds. <br />n an azr qua 1 ing <br />s.ummarizod Frei~~_. ~, , .__,~ Hi7e~ <br />GEOLOGY n r N r A v C ~~~-j'6.. 0/ <br />The Pittsburg and Midway Co.al~Cnmpany'~ Gdna mine is geographically situated between <br />the drainages of Oak Creek on the East and 'Prout Crock, on the 'rh7st. Topographically, <br />the permit area is dominated by a worth-South trendzng ridye line, r.•ith a steep East <br />facing escarpment ending at Oak Creek, and a more gently [:'est lacing dip slope from <br />the ridge line to Trout Creek nn the ;:'est. Elevation of the area ranges from 7,000 <br />to 7,600 feet. <br />Except for surfical deposits, onlu the coal bearine Cretaceous ;Mesa Verde Grouo out- <br />crops in the permit area. The r/illiarns ForF; Formation and tiie Iles Formation together <br />comprise the Mesa Verde Groun. Tire t:'i 111 ams Fork Formation is separated from the lower <br />Iles Formation by the massive Trout CzceF: Sanrlsr_one Flumher, t•he top of which .`orms the <br />upper limit of the Iles Formation. Tho coals to b~: mined at the Edna site are all <br />situated within the h'illiams ForF; Formation, appro:ri.motely 150-225 feet above the Trout <br />Creek Sandstone. The "mirld_'e ,jroup cea of the lower coal bearing member include, <br />in ascending order, theme[/olf Crud, and Lenr:o:; coals. <br />The major portion of the Edna mL-ra i:^ located nn tiro eastern limb of the Twenty hfile <br />Park Syncline, the axis of i. ;bleb trends northwest from the southernmost boundary of the <br />permit area through C'est Ridge. Two mino•- faults occur in the r~foffat area. <br />Landscape character in and rmar <br />strata followed by differential. <br />thicF;nesses. The southern port <br />large areas of previouslu stria <br />®pp-/n~3 dragline operation. <br />GROUND [•JATER <br />the Erina mine resuiLs mostly from moderate folding of <br />csn::ion or' .nt~~rl.,•xidcd hard and soft lagers of various <br />r~.~n of thr_ mine ;•e Wait area, [;'est Ridge, con s:a is of <br />mined land rd~i ch r~~ma.i::ffD~ss poll cidyes lett by ~A <br />The applz.ca 's ground water investigation zs coot fined in .4ect' -.5.2.3 0~ t <br />applic on. Gro water f1o,~~s through c'~ zn strat.i9ra,(see ~zgure 2.6-I4) <br />a through a vial material in the mrt area. <br />..o rrS <br />The Wadge coal seam Pt~-overburden, and the immrediate underburden am all water- <br />bearing. However, the First rock unit below the Wadge Coal r.~ith any significant poten- <br />4l s N.`J <br />tial as aA,~'"aquiter is the 'Grout cr•,ck Fanristnne. Generally, thr_ h'adyn_ Coal, ttre over- <br />burden, and the immediate undor}>u rdcn all have Iimi tcd ahi li ty to transmit si 9ni fi. cant <br />uantities of water. Aquif<^r properties, as deterrnincd from single-hole performance <br />tests, indzcate transmi ssi vi ty values .in the ran yc of 0.: to 39 ft2/day for the coal anc <br />the overburden and underburden (sco Tah1c 2.6-i3). Thcsc values indi c•~tc that the <br />G w <br />