Laserfiche WebLink
<br />• Frequent bedrock outcrops were identified on the west side of <br />the valley. The slopes of this valley side are steeper than on the east <br />side and much of the ground surface consists of exposed bedrock. Col- <br />luvium, where present, is very thin and loose and it is generally less <br />than 6 inches deep. The soil may be thicker in collection areas at the <br />mouth of larger gullies. The bedrock outcrops are formed by mostly <br />gneiss or granitic rocks; most of the rocks are very hard and apparent- <br />ly highly resistant against weathering. <br />During our mapping program, attention was paid to any potential <br />stability problems not related to mining activity in the area. The <br />study area was carefully inspected and checked for any signs of potential <br />stability problems such as old landslides, rockfall areas, potentially <br />unstable zones, etc. Aerial photographs made available by Cotter <br />Corporation were very helpful in supporting the field mapping. No traces <br />traces of larger scale stability problems such as landslides; or rock- <br />falls that might endanger the stability of the waste piles in the <br />• future were found. The area carries traces of rockfall of a minor <br />scale and there are traces of erosion on the slopes. It is the engineer- <br />ing geologist's opinion that none of these features can influence the <br />existing or future stability of the waste piles unfavorably. <br />3.2 Ground Water <br />Ground water conditons have not been studied in any detail as <br />they have very little influence on the stability of the existing and <br />future waste piles. According to previous studies performed for Cotter <br />Corporation by WATEC (Anticipated Post-Mining Hydrology of the Schwartz- <br />walder Mine, Jefferson County, Colorado, Appendix E-2 of the 1977 Permit <br />Application), there are two aquifers identifiable in the Schwartzwalder <br />Mine area; Quaternary alluvium of Ralston Creek and the Ida~~o Springs <br />Formation aquifer. Of these two, only the alluvial aquifer has an.y <br />importance for the stability of the waste piles. However, potential <br />• <br />-9- <br />