2014-06-16_HYDROLOGY - P2013002 - Laserfiche WebLink

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Ms. Angela Bellantoni June 9, 2014 Page 2 mile radius are down-gradient of the mine excavation. As a result,there is no potential for the interception of ground water within the mine itself to impact any water supply wells. Available data completed as part of the mine exploratory operations indicate an aquifer is not present at the mine location. Also,the limited ground water development within a two mile radius of the mine suggests that ground water development potential is limited. Similarly,the potential future ground water development at the site is limited because the mine area and neighboring lands consist of BLM lands, mining claims and steep mountain topography. The mine will result in surface and ground disturbance in two drainages tributary to the Arkansas River. The eastern disturbance area at which the mine pad will be located is herein referred to as the Dawson drainage, and the western disturbance area is referred to as the Windy Gulch drainage. As explained below,the baseline monitoring points are focused on down-gradient locations in these two drainages. Both drainages below the mine area are normally dry. We completed a site visit on September 19, 2013, which followed a period of heavy rains and regional flooding in. Colorado. 4.6 inches of rain occurred in the Canon City area within 8 days of the field visit, and 1.0 inch of rain had occurred within 4 days of the field visit'. Nevertheless, the drainages were dry on the day of our field visit. Surface flow in the drainages will probably occur only during precipitation events and during snowmelt periods. We anticipate that for most of the monitoring events, there will be no surface water present at the proposed surface water monitoring points. G and water conditions at the location of the proposed monitoring point are not known because of the lak of borehole data at this location. However, we anticipate that ground water will be encountered at relatively shallow depths because the proposed monitoring points are at the bottoms of mountainous drainages, and we suspect that the ground water surface mimics the ground surface topography. As such, the ground water flow direction is generally from south to north, mimicking the surface drainages. It is possible that the proposed ground water monitoring points will be dry at relatively shallow depths as a result of possible low permeability bedrock conditions. Function of Monitoring Points Prior to the start of mining, the monitoring points are intended to provide baseline data representative of pre-mining ambient conditions for the 15-month baseline monitoring program required by the DRMS permitting process. Data collected from the points will help to establish baseline hydrologic conditions at the mine locations and will generally help to characterize the hydrology at the mine site. During mining, the monitoring points will function in a way that monitors and identifies any change in ground or surface water quality resulting from the mining activity. By identifying changes in water quantity or quality, the monitoring points will function as an early warning system alerting the mine operator if changes in water quality are detected. It is our opinion that the proposed monitoring points are adequate for baseline monitoring purposes for the following reasons: Ground Water Monitoring_Points • The closest water supply wells to either mine disturbance area is approximately 0.65 miles away, and water supply wells are all down gradient of the mine. There are no wells located in the mountain area at which the mine is located. I� t Source:precipitation data from the"KCOCANON"weather station.