Laserfiche WebLink
24HG2E27XC Sample Hole(s) Project Plan <br />Minor Revision 320 <br />Page 8 of 11 <br />Mud pits will be designed to contain the run-off from a 25-yeaz 24-hour event and will be <br />constructed in subsoil (native soil). Mudpit designs and calculations for 1.0 foot of <br />freeboard have been previously approved by the CDMG. <br />Water for the drilling operations will be pumped to the drill sites from the mine <br />dewatering polishing pond using high-pressure hose in combination with frac tanks and <br />high-pressure pumps. Mountain Coal Company, L.L.C. owns water rights for these water <br />resources. <br />DRILLING ACTIVITIES <br />Drilling activities for the proposed methane drainage wells will include mobilizing drill <br />equipment to the sites and drilling and setting approximately 40 Feet of 16-inch surface <br />casing into bedrock. The holes will be rotary drilled with a 10-inch diameter hole to the <br />B-Seam, then cased with 7 ID steel casing. A depiction of a typical completed well will <br />be forwarded to the CDMG along with the typical plug and abandonment diagram. <br />MONITORING <br />Currently, MSHA is requiring monitoring and inspection of the wells twice daily after <br />installation. It is anticipated the frequency of monitoring would decrease to a weekly <br />monitoring and inspection of the installation. Routine maintenance will occur to the <br />extent necessary, simultaneous with the weekly monitoring. <br />PROPOSED DRILL HOLE PLUGGING METHODS <br />In accordance with the Coal Program Guidance Document -Methane Drainage and <br />Monitoring Wells, MCC will plug and abandon these MDWs per DMG Rules 2.05.4 and <br />4.07.3 at the minimum. A mechanical packer will be set at the lowest possible point in <br />the well (note that subsidence damage to the casing may preclude access to the entire <br />depth of the casing). Above this packer the hole will be plugged with CDMG approved <br />materials to the bottom of the 5-foot cement surface cap using tremmie line. The top 5- <br />feet of the well below the sub-surface casing cut-off point (3-feet below the surface) will <br />be plugged with a cement cap. The top 3-feet of the casing will then be cut off and the <br />hole filled in with subsoil. A permanent marker shall be installed on top of the plug <br />identifying the well. The pad will then be reclaimed to approximate original contour. <br />The Methane Drainage Well and other drilling experience for Mountain Coal Company <br />has shown that no aquifers have yet been encountered. However, the procedures <br />described above would serve to properly protect any aquifers that would be encountered. <br />