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<br />hole was bypassetl by mining. The hole was cemented to prevent rapid discharge of water from the <br />hole into the mine workings. This monitor hole was replaced by drilling and completing a new hole <br />in 1986 in the general vicinity of the other 2-17 holes. <br />The Colorado Mine Land Reclamation Division in October of 1984 relaxed the monitoring requirements <br />for those monitor holes located in Federal Coal leases C-8424 and C-8425 with the stipulation that <br />monitoring would again resume at these holes. The resumption of monitoring at holes located at sites <br />29-4, 30-8, 31-7, 32-7, and 33-8 will begin one year prior to any mining activity in the lease in which <br />the holes are located. DMG's relaxation of monitoring also eliminated water sample collection from <br />all bedrock monitor holes except that water samples will be collected on a biennial basis upon <br />resumption of monitoring. Those samples collected will be analyzed according to the schedule shown <br />in Table II.C-S in Section II.C.2.e. <br />Monitor hole 2-12U is located near the center of longwall panel No. 1. This hole showed a significant <br />drop in water levels that corresponded in time with the passable of the longwall and subsequent <br />subsidence. Subsidence caused cracks, etc. obviously disrupted the "upper sandstone facies" <br />piezometric levels locally. The water level somewhat recovered and appears to have stabilized. <br />However, this data is questionable and 2-12U has been dropped from the monitoring program. <br />Alluvial monitor hole t]al-5 will be monitored monthly for water level and field parameters of pH, <br />conductivity, and temperature. Water samples from Qal-5 will be collected quarterly and analyzed as <br />per Table II.C-8. Water levels of the bedrock monitor holes will be measured quarterly. <br />Nine (9) new alluvial monitoring holes were installed in Red Wash (see Map 137) during the spring <br />or summer of 1986. These holes were installed to monitor water levels during the mining of Longwall <br />Panel No. f. After installation of these holes, water levels were measured once every two months. <br />When the longwall face has advanced to within 200 feet of the Red Wash alluvium, water level <br />monitoring began on a schedule of once every two weeks and continued on this schedule until the <br />longwall face had advanced past the alluvium 400 feet. Thereafter, monitoring resumed at a schedule <br />of once every two months until longwall mining in panel 1 was complete. Results of the Red Wash <br />monitoring have been reported in the Deserado Mine Annual Hydrology Report, and in an Interim <br />Report submitted to CMLRD in November 1987. <br />The purpose of the Red Wash alluvial monitoring program was to determine whether surface flow in <br />Red Wash would be lost to bedrock as a result of subsidence. The major conclusions of the program <br />were: <br />• Surface flow in Red Wash is not lost to bedrock as a result of subsidence <br />• Recharge of the basal alluvium is from the upper sandstone facies (bedrock) and not from <br />infiltration of surface runoff. <br />(Renewal fl2, 5/94) II.C-76 <br />