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The hole was tested by slug-injection, but results were inconclusive. <br />• The residual head actually increased after injection rather than <br />decreasing (Exhibit 2). <br />HOLE N0. M-2 <br />Drilling <br />This hole was drilled to a total depth of 530 feet. The various coal <br />seams above the Upper Sandstone were encountered in this hole (Exhibit <br />3, Figure 2). Ground water was noted in three distinct zones, 80 <br />feet, 242 feet, and 482 feet (Exhibit 3). Total flow from the three <br />zones under drilling conditions was greater than 300 gpm. <br />Temperature, pH, and conductivity measured during drilling indicated <br />the upper two producing zones have similar water chemistry, whereas <br />the water quality of the deepest zone is slightly different (Exhibit <br />3). <br />• The Colorado Division of Mined Land Reclamation decided the deepest <br />producing zone need not be monitored, because it was between the upper <br />and middle sandstones and, therefore, immune to mining effects. This <br />required that the hole be plugged back to about 340 feet. (This deci- <br />sion was based on the mistaken belief that the main producing zone was <br />the middle sandstone. The 482-foot zone is actually within the Upper <br />Sandstone.) <br />The first attempt at setting a plug was done by running ground (32 <br />feet3) from the bottom of the hole to 415 feet and pouring 100 gallons <br />of cement slurry down the drill pipe to yield a 60-foot thick plug. <br />However, the lowest producing zone was under higher artesian pressure <br />than expected, and the cement plug was washed up the hole suggesting <br />that a shallow zone was taking water produced down hole. <br />n <br />