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New Horizon Adjacent North Ground Water Monitoring Holes <br />180 Day Report <br />2.) <br />Four holes were drilled at each of the three sites. One of these holes at each of the sites <br />was drilled as a pilot hole and logged with geophysical tools. The other three holes were <br />constructed as groundwater monitoring holes. At each site, one monitoring hole was <br />constructed in the overburden above the coal zone, another within the coal zone, and the <br />third below the coal zone. <br />All holes were drilled using a truck-mounted rotary drill rig. The pilot holes were drilled <br />to a diameter of 5-5/8" and were drilled through the Nucla Seam, a thin coaly shale seam <br />usually found between 15 and 30 feet below the Upper and Lower Dakota seams which <br />are the seams targeted for mining. <br />Each monitoring hole was drilled to a diameter of 6-3/4". Once drilled, the hole was <br />cased with 4" schedule 40 PVC casing. In the case of the holes that monitor water above <br />the coal zone, the total depth of the holes was several feet above the Upper Dakota (UD 1) <br />seam. The lower ten feet of casing in each monitoring hole was mill-slotted PVC. <br />Above the slotted casing, a soft-formation packer was placed on the casing and 3/8" <br />bentonite pellets were poured down the annulus on top of the packer to an elevation of <br />ten feet above the packer. Drill cuttings were then shoveled on top of the bentonite <br />pellets to a depth of five feet from the surface. Concrete (sakrete, dry mix) was used to <br />grout from the surface to the top of the drill cuttings. <br />The holes monitoring groundwater within the coal zone were drilled to the bottom of the <br />Lower Dakota (LDx) seam. Slotted casing was used from the total depth to the top of the <br />UD1 seam. A soft-formation packer was installed above the slotted casing and 10 feet of <br />bentonite chips filled the annulus above the packer. Drill cuttings were placed in the hole <br />to a depth of five feet from the surface. The final five feet was grouted with concrete. <br />The holes completed below the coal zone were drilled to a depth of fifteen to 30 feet <br />below the LDx seam. Slotted casing was used from the total depth to just below the <br />bottom of the coal seam. A soft-formation packer was placed just below the bottom of <br />the lower seam and 3/8" bentonite pellets were poured in to a depth of several feet above <br />the UD1 seam. Drill cuttings were placed in the hole to a depth of five feet from the <br />surface. The final five feet was grouted with concrete.