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EFCI <br />Page 2 <br />June 13, 2014 <br />well penetrating and screened within the coal zone rises to a level significantly above that of the coal <br />seam. The interbedded mudstones and siltstones located above and below the coal act as aquicludes and <br />greatly restrict vertical groundwater movement. in a confined saturated zone /aquifer such as is the case <br />with the Jack O'Lantem and Red Arrow coal seams, the water entering the well screen rises as much as <br />several hundred feet above the perforated interval of the well. This was verified in the recent DRMS <br />Groundwater Review for the Southfield Mine, where available water level information was plotted on <br />cross - sections for wells completed in the Red Arrow and Jack O'Lantern coal seams. In all cases the <br />information showed potentiometric head at levels in excess of 100 feet above the perforated interval of <br />the well, and in some wells much greater than that depending on the depth of overburden and <br />confinement. <br />When an area is mined using room and pillar technique and retreat mining, the in -situ groundwater <br />conditions are greatly altered. The existence of the mine workings will permanently modify the pattern of <br />ground water flow. The flooded mine constitutes a region of essentially infinite permeability that will <br />tend to cause ground water to preferentially pass through the workings. The coal mining area gob that is <br />left behind after the coal is removed, is highly fractured and rubblized. The mined out area is no longer <br />under semi - confined or confined conditions. The hydrostatic pressure created by the overlying confining <br />beds no longer exists in the gob area of an underground coal mine, due to the disruption of the confined <br />conditions and the high level of porosity and permeability created by removal of the coal and rubblization <br />of the roof material and surrounding strata. If and when, the mine -inflow water reaches the area of the <br />mine that the steel casing of MW -NW is installed, the water would not rise into the casing above the level <br />of the roof due to the lack of pressure head. <br />Removing the blockage in the well would be beneficial so that the assumptions regarding whether or not <br />the mine is dry or saturated in this section of the mine could possibly be verified. MW -NW is located at <br />an up gradient region of the underground mine workings, with the dip of the coal seam away from MW- <br />NW to the northwest. The lowest point elevation in the mine is at 5265 feet, which is significantly below <br />the level of the bottom of the MW -NW steel casing. <br />Bishop - Brogden Associates, Inc. of Denver, CO has concluded through research and modeling that water <br />in the mine will not reach the observation point elevation for the MW -NW well for over 100 years after <br />the year 2000. These conclusions may be verified by removal of the blockage in MW-NW. <br />Thank you for your ongoing cooperation, and please contact us with any questions. <br />Sincerely, <br />`David'Berry <br />Dire�for, Coal Mine Regulatory Program <br />