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2.04.7 Hydrology Description <br />In well 2010 -1SS completed in a sandstone water bearing zone located <br />above the B -Seam the average conductivity is 4,125 umhoslcm with a range <br />of 3,800 to 4,500 umhoslcm, the average ph was 12.7 with a range of 12.3 to <br />12.9, average total iron was 1.21 mgll with a range of 0.18 to 5.14 mgll and <br />average manganese was 0.04 mgll with a range of 0.02 to 0.13 mgll for the <br />years 2011 and 2012. <br />The PR -13 mine plan area, west of Terror Creek, has up gradient and down <br />gradient monitoring wells. CWI -58 and CWI -DH -60 are up gradient <br />monitoring wells and 2010 -1 B and 2010 -1 SS are down gradient monitoring <br />wells. See Map 9 for well locations. <br />The down gradient monitoring wells will be mined through during 2015 based <br />on current mine plan timing. Thus the PR -14 mine plan area in federal coal <br />lease COC -75916 will not have down gradient monitoring wells. <br />Replacement down gradient monitoring wells would need to be installed <br />north of the West Fork of Terror Creek with depths exceeding 1,500 feet. <br />The Operator does not believe it is economical or technically practicable to <br />install replacement down gradient monitoring wells at these depths. The <br />discussion above documents the difficultly and expense of installing deep <br />bedrock monitoring wells. <br />It is highly unlikely the public will use the deep bedrock groundwater located <br />north of the west mine plan area west of Terror Creek. It is simply too <br />expensive to install a domestic or livestock well at such extreme depths. The <br />poorwater quality would also discourage public use. Additionally, the USDA - <br />FS manages the land to the north of the west mine plan area. It is unlikely <br />the USDA -FS would approve the installation of a deep bedrock water well on <br />the land it manages. It is over four miles to the nearest private land owner <br />which further reduces the likelihood of public use of the water. The lack of <br />deep bedrock groundwater monitoring data after 2015 is mitigated by the <br />highly unlikely public use of the water. <br />(b) The subsurface hydrologic regime may be divided into four discrete <br />subsystems: 1) the alluvium and terrace deposits associated with the North <br />Fork of the Gunnison River; 2) localized deposits of alluvium - colluvium within <br />the Hubbard Creek, and Terror Creek areas; 3) groundwater occurrences <br />within the Mesaverde Formation; 4) colluvial discharges associated with soil <br />PR -14 2.04-36- 03114 <br />