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The water that was discharged from the old abandoned underground coal <br />• mine into the surface pond located in the final pit of the previous <br />surface mining activities was low in pH. Because the old abandoned <br />underground coal mine workings dipped upward away from the entries, <br />there existed the situation of gravity discharge from the abandoned <br />workings. However, the relative shallow dip of the abandoned workings <br />allowed any subsurface water that percolated into the abandoned workings <br />to mix with the remaining coal and cause an oxidation reaction with the <br />pyritic sulfur in the coal to form sulfuric acid, thereby lowering the <br />pH of the water. The pH of the water found in the old pond was field <br />checked several times and found to be 3.0 or below. <br />-`-••°, Peerless Resources, inc. reclaimed the old pond in <br />late 1984 but left a pipe extending out of the abandoned workings for <br />discharge into the sediment pond. The location of this pipe and the <br />discharge point is shown on the revised Mine Facilities Map (Map 12). <br />• The March, 1985 quality measurement of the discharge from this pipe <br />indicates that the pH of this water is now approximately 5.0. Although <br />still somewhat on the low side, this pH reading is considerably higher <br />than the field measurements noted in the old abandoned pond in mid-1984. <br />Peerless Resources, inc. believes that as the abandoned workings are <br />"flushed" over a period of several years, the pH of the water should <br />continue to rise to a more neutral level. Also, as water fills that old <br />workings, the oxidation process with the coal should be minimized or, <br />hopefully, eliminated. <br />Following completion of mining by Peerless Resources, Inc. in the <br />planned Coal Gulch Mine, the portals will be sealed with concrete cinder <br />block retaining walls. Pipes will be left at the top of the entries to <br />allow for both possible methane discharge or subsurface water discharge. <br />As subsurface water accumulates behind the seals of the closed Coal <br />Gulch Mine, the chance for oxidation with the pyritic sulfur in the coal <br />should be minimized. In fact, over time as the old workings are filled <br />• with subsurface water, no or only minor amounts of oxygen should be <br />present. Subsequently, Peerless Resources, Inc. does not anticipate any <br />long-term problem with low pH drainage from the closure of its planned <br />operation. <br />2, u y- l7 A ~~R 0 4 t~~6 <br />