2015-04-06_REPORT - C1981022 - Laserfiche WebLink

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to the Rollins Sandstone unit which is located stratigraphically under the footprint of the mining activities. Water in the Rollins Sandstone is confined to limited localized zones that are fractured and /or contained above the Rollins, as evidenced by past water level measurements that are well above the top of the sandstone member. Water quality is poor, with high total dissolved solids as sodium chloride. Inflow and recovery of the water level in the drill holes indicates very low permeability and porosity of the sandstone. The 2012 sampling indicated a substantial drop in dissolved solids, chlorides, etc. These parameters appeared to return to "normal" in 2013. A review of the long term water level appears to show a continuous drop in water level elevation, suggesting low transmissivity of water into the sandstone from the upgradient river. In 2014 the water level was so low there was barely enough to trip the sounder recording the water level. During 2014, there was insufficient water for bottled samples. Generally, the limited water quantity and poor water quality suggests there is limited transmissivity between the North Fork of the Gunnison River alluvium through the Rollins sandstone down- gradient towards the area associated with the Sanborn Creek Mine. SC -3 Well - B -Seam Coal — Sanborn Creek Mine Monitor well SC -3 is located east of the Sanborn Creek reclaimed mine portal area along the entrance to the pre- existing ranch road to Coal Gulch. Monitoring well SC -3 was completed into the B Seam coal. Monitoring data were collected from well SC -3 prior to any substantial mining in the B -Seam of the Sanborn Creek Mine. The SC -3 well is up- gradient relative to the B seam underground mining activities but down- gradient from the North Fork of the Gunnison River The plastic pipe casing is squeezed at the 20 foot level making it difficult to lower a bailer. Using a smaller diameter bailer we have found very minimal water available in the well. In fact there are times when the initial bailing of the well to remove one volume effectively drains the available water. The lack of water in the well and the poor water quality suggests there is little transmissivity and connection between the North Fork of the Gunnison River and the B seam coal at this particular vicinity of the mine. The elevated 2012 levels of zinc and iron appeared to return to "normal" but sulfate seemed to remain elevated. Perhaps the lack of water in the well is skewing the results. Overall depth appears to be "normal ". As the locations of SC -1 and SC -3 wells serve to monitor only the Rollins sandstone and B -seam coal respectively up- gradient of the Sanborn creek mining area, their utility towards the monitoring of the Sanborn Creek mine itself remains somewhat limited. 6.0 Mine Water Information Elk Creek Mine Water The water utilized in the mine continues to be all imported from the alluvial water supply well located near the North Fork of the Gunnison River per the OMLLC water rights and Augmentation Plan. Water that is collected and routed to the underground Elk Creek mine sump 17