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per year, installation of a ventilation portal along the <br /> outcrop, and an increased inflow constant for unknown <br /> conditions. <br /> On the north side of Jumbo Mountain colluvium from an <br /> ancient landslide that removed the minable portion of the <br /> B-seam lies directly atop the lower portions of the B-seam. <br /> Water could be expected to infiltrate through the colluvium <br /> and migrate from bedrock units into the colluvium, emerging <br /> as springs or seeps down-dip of the proposed mining <br /> The B seam mine will not cause significant hydrologic <br /> impacts to groundwater systems in the five-year permit area <br /> based on the data provided. <br /> The majority of springs (shown on Map 55 and 37A) are <br /> located at or above the F seam outcrop. A few springs have <br /> been identified between the E and F seam outcrops. No <br /> springs have been identified below the E seam outcrop. <br /> Monitoring of springs for baseline data and to assess <br /> impacts of mining in the F seam has been carried out for <br /> the past ten years by MCC. Evidence to date indicates that <br /> mining has very little, if any, impact on spring flows. <br /> The depth of overburden where the B seam will be mined in <br /> the area of the springs ranges from 400 to in excess of <br /> 1,000 feet. Based on experience in the F seam and <br /> geotechnical work, the springs will not be affected <br /> significantly by mining in the B seam under these <br /> overburden depths. <br /> Some inflows to the mine are expected as mining proceeds <br /> under Lone Pine and Gribble Gulches as the valley features <br /> are fracture controlled. Inflows in these areas are <br /> estimated from 2 to 20 gpm. It is anticipated that the <br /> flow will be in the middle or lower end of the range. <br /> If flows into the mine approached the maximum estimated, <br /> 20 gpm, this would only be approximately 14 percent of the <br /> peak spring runoff flow. For this to occur or deplete <br /> spring flow, a direct fracture connection to the mine <br /> workings must occur and remain open. To date, this has not <br /> occurred in Lone Pine Gulch in the F seam under cover as <br /> low as 120 feet. <br /> The water balance will not be significantly affected even <br /> if the maximum estimated inflows occur, since any mine <br /> inflows will ultimately be discharged back to the North <br /> Fork of the Gunnison. <br /> i. Refuse Material Disposal Impacts on Ground Water - <br /> Lower Refuse Disposal Area - Refuse is generated <br /> through the mining process and will be disposed of on <br /> the Lower Refuse Disposal site. The lower refuse <br /> pile is permitted for permanent disposal of 1.09 <br /> million cubic yards of mine development waste, and <br /> sediment pond cleanout material. <br /> To date the lower refuse pile has not impacted the <br /> ground water zone near Sylvester Gulch. Because of <br /> the low permeability of the colluvial soils and the <br /> lack of a ground water table near the surface in the <br /> colluvium, no impacts on ground water are <br /> anticipated. water monitoring well SG-1, located <br /> 31 <br />