2020-03-24_PERMIT FILE - C1981019A (2)

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RULE 2 PERMITS wells A-7 and A-8 reveal a water table that is at least 10 feet below ground surface. Based on field and monitoring data, the West Fork Good Spring Creek is not an alluvial valley floor. The area of Wilson Creek below the Lower Wilson Mine and extending north about four miles is an area that was formerly described as a potential AVF and was mapped as such by some (OSM, 1985). This area was subjected to a flooding and mass -wasting event that downcut the alluvium 20 to 30 feet below the former surface and left two narrow terraces 20 to 30 feet above Wilson Creek on either side of the creek. These terraces are generally no wider than 100 feet and in many places are much narrower than 100 feet. A monitoring well in this section (well MW -95-03) was installed to the base of the alluvium at the mouth of the unnamed drainage holding the Lower Wilson expansion area. This well, installed during the summer of 2005, is 57.34 feet deep and encountered angular "clinkers" and no stream -rounded alluvium. The well had 3 feet of water in August 2005, but contained only a few tenths of a foot of water in September and October 2005. This indicates that the alluvium in the terraces is dry and is not sub- irrigated. The narrow width and fragmented nature of the minimal flat land, depth to groundwater, and impracticality of irrigating or mechanically farming this stretch of Wilson Creek indicates that it does not qualify as an alluvial valley floor. However, mining will in no way adversely affect the ability to irrigate or farm any agriculture or potential agriculture area, including this area. Water Quality and Quantity Since 1974, Colowyo and other private and governmental groups (VTN, BLM, and USGS) have collected samples of water flows and water quality. The results of all this work is summarized in section 2.04.7. Aerial Photograph Analysis Aerial photographic coverage of the permit area and adjacent area has been complied by the OSM in Denver, Colorado. The photographs are infrared and show the late summer and fall season differences in vegetative growth between upland and valley floor areas. Good Spring Creek appears in the aerial photographs to possibly be an alluvial valley floor. Effects on Essential Hydrologic Functions Based on information accumulated, the effects of mining on any alluvial valley floor which exist in the general area would be minimal. Because of the undefined perched existences and limited amounts of bedrock groundwater in the area to be mined, the planned mining will not directly impact any alluvial valley floor. Any water recharge of the nearby drainages and unconsolidated material from the mine would be negligible in comparison with the overall natural flows of the streams recharged in areas above the operation. The flood plains of Good Spring Creek, portions of Wilson Creek, and lower Taylor Creek may meet the geomorphic criteria and flood irrigation requirements of an alluvial valley floor. Runoff from the mining operations drains into these floodplains. Therefore, Colowyo has taken and will take appropriate measures to protect surface water. This includes designating stream buffer zones and installing sedimentation ponds on the drainages from disturbed areas feeding into surface water features (see Hydrology maps l0A and 11A). The overall role of the floodplains in collecting, storing, regulating and yielding water for agricultural activities has been unchanged and is anticipated to be unaffected by the mining operations. South Taylor/Lower Wilson — Rule 2, Page 89 Revision Date: 4/7/17 Revision No.: RN -07