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J <br />.. ~ <br />~ ,~ <br />reduce the amount of water storage in sediment pond(s) and treatment prior to <br />discharging into coal gulch. In addition, the applicant will not extract <br />pillars adjacent to the main mine entries. The barrier pillar between the <br />mine main entry and the panels will remain in place following mining. These <br />procedures will also help minimize impacts to the ephemeral drainages. <br />Stipulation No. 20 <br />IN ORDER TO DETERMINE THE SURFACE EFFECTS OF SUBSIDENCE, A SUBSIDENCE <br />MONITORING PLAN, AS OUTLINED IN FIGURE N0. 1, WILL BE IMPLEMENTED. THE <br />MONUMENTS WILL BE ESTABLISHED AS ILLUSTRATED IN FIGURE N0. 2. <br />ALL MONUMENTS WILL BE SURVEYED TWICE PRIOR TO POSSIBLE SUBSIDENCE. <br />THEREAFTER, SEMI-ANNUAL SURVEYS WILL BE MADE. THIS DATA WILL BE <br />REPORTED GRAPHICALLY AS CROSS SECTIONS AND SUBSIDENCE PROFILES. <br />THE SUBSIDENCE REPORTS WILL BE SUBMITTED TO THE DIVISION ANNUALLY ALONG <br />WITH THE REQUIRED HYDROLOGY INFORMATION DISCUSSED ABOVE. <br />Most Probable Scenario After Coal Gulch Abandonment <br />Subsidence from the proposed Coal Gulch Mine should intercept most of the <br />Cliff House water which is presently flowing into Victory No. 1. This is due <br />to subsidence processes creating secondary permeabilities up-gradient from <br />Victory No. 1, effectively cutting off its recharge. <br />The proposed Coal Gulch Mine will have been constructed in such a way so as to <br />minimize subsidence of the unnamed ephemeral drainage. Pillars will not be <br />removed under any area where the surface elevation is 7,400 feet or less. <br />Therefore, total maximum inflows to the proposed permit area shortly after <br />spring runoff are expected to be 5 gal/min from Victory No. 1, 30 gal/min from <br />proposed Coal Gulch Mine; or 35 gal/min (50,400 g/Day, 0.15 AC FT/DAY). This <br />water would still be of unacceptable quality, approximating present <br />Victory No. 1 discharge quality, and would need to be contained and treated <br />before being discharged into Coal Gulch. <br />During the summer, inflows would probably drop to 1 gal/min or less at the <br />Victory No. 1, and flow 3 to 5 gal/min from the Coal Gulch Mine. <br />There is no present use of water from the upper Meneffee/lower Cliff House in <br />this area, and no springs discharging usable amounts of water down gradient of <br />mining have been identified. The greatest change to the system will be <br />increased permeabilities due to bulking, bed separation, and/or fracturing of <br />the lower Cliff House.. This area of increased permeability will encourage <br />continued ground water flow toward the abandoned mines. The effect of this <br />change in potential to the entire Cliff House system should be minimal, as the <br />major component of flow will still be towards Sheep Springs Gulch. <br />