Laserfiche WebLink
1 <br />1 <br />1 <br />1 <br /> <br /> <br /> <br />1 <br /> <br />intercept it. As it turned out, the hole was never encountered in the workings. As required by <br />CMLRD, a new hole was drilled and completed in the 'lower sandstone facies'. From the time the <br />new hole was completed, the water levels in this hole have fallen. During May 1986, mining in gate <br />road 2nd East intercepted an exploration hole, (21012-9) that had been drilled in 1978. This hole <br />had been plugged with heavy mud but leaked from both the mine roof and floor when the hole was <br />intercepted. Water flow from the hole in the roof was about 3 gpm (gallons per minute) and was <br />plugged with a packer. The flow from the hole in the floor was on the order of 1 gpm and was <br />plugged by pumping an expanding grout into the hole. This exploration hole is located about 1500 <br />feet from 2-17L and the leak in the floor may have reduced the piezometric pressure in the 'lower <br />sandstone facies° at 2-17L During March of 1987, another exploration hole (21012-10) was <br />intercepted by mining in gate road 3rd East. This hole also leaked at about the same rate from roof <br />and floor. The hole in the roof was plugged with expanding foam grout. The hole in the floor was <br />plugged with Portland Cement pumped down a one inch line to about 100 feet. The leaks in both <br />21012-9 and 21012-10 are probably responsible for the fall in water levels detected at 2-17L during <br />the fourth water year. Mining of LW-1 approached tc within 500 feet of this hole in February 1988. <br />During this monitoring period, the water level remained beyond the capability of the monitoring <br />equipment (deeper than 300 ieet). Perhaps the combination of leaking exploration holes and floor <br />cracking as coal was removed by the ingwall have reduced the piezometric pressure enough to <br />drop the water level below 300 feet. Monitoring of this hole will continue to see if it recovers. <br />' Monitor holes 2-7L and TW2-7L are on the same location and apparently also responded to the two <br />leaking exploration holes. Longwall panel 3 was mined past this location in April 1990 and the water <br />level has since dropped below 300 feet. Longwall panel 4 was mined past this location in August <br />1991. The water level in these two holes remained below 300 feet during this monitoring period. <br /> <br />t <br /> <br />1 <br /> <br />1 <br /> <br />Monitor hole 36-2L showed a drop of 46.5 feet during this period. Monitor hole 35-4L dropped <br />below 300 feet during this period. As noted previously, both of the locations are being approached <br />by mining activity and declines in the piezometer levels were anticipated as a result. <br />Monitor hole 4-20L showed a relatively static water level during this monitoring period. <br />The response of 'lower sandstone facies' monitoring holes 2-17L, 2-7L and TW2-7L to mining and <br />leaking exploration holes indicates the area of influence in the °lower sandstone facies' is larger than <br />that in either the °upper sandstone facies' or the "siltstone-coal facies". However, the response of <br />these monitoring holes to low flows of about 1 gpm in the leaking exploration holes further indicates <br />the low water flow characteristics of the "lower sandstone facies'. <br />From the baseline data, all three zones should be classified as °aquitards° in that they will yield <br />water but at very slow rates. Mining in the D Seam so iar has encountered only small flows of water <br />10 <br /> <br />