Laserfiche WebLink
Cottonwood Spring is likely groundwater that is derived from strata shallower than the bedrock that is <br />directly in contact with the backfill aquifer in this area. <br />The Fox Den Spring is located on the eastern flank of Oak Gulch approximately 800 feet north of the <br />nearest upgradient mining activity in the initial cuts of the A East pit. Mining in this area has to date had <br />no obvious effect on flows at this site. Flow from this spring is not expected to be impacted during post- <br />mine conditions. This spring exists near the southern limits of the Third White Sandstone outcrop and <br />has been thought to emanate from the Third White Sandstone. A travertine deposit has been noted to <br />exist on the surface at the site of the Fox Den Spring. This deposit may indicate that water quality from <br />this spring was significantly different in the past for some period, or that the source of this spring is from a <br />deeper aquifer containing more highly mineralized water. Sulfate and TDS concentrations measured at <br />the Fox Den spring are similar to levels documented in Third White Sandstone wells GC-2 and GP-9. <br />A deeper source for the Fox Den spring would require that a permeable zone exists to transmit the water <br />to the land surface. Though no obvious geologic structural features have been identified in the immediate <br />vicinity of the Fox Den Spring, some subtle indications are present. A similar travertine deposit was noted <br />to exist at springs to the east in Flume Gulch (Spring 99-2 and Spring 99-3). The alignment of these <br />springs and the Fox Den Spring roughly paralleled a northwest/southeast trending regional fault system, <br />the Cedar Mountain fault system, north of the project area. This is the dominant geologic feature in the <br />area. The Big Bottom Syncline may have smaller displacements or slips associated with it that could <br />conceivably transmit water. This type of feature could account for flows at the Fox Den Spring. The <br />lithologic units at Trapper have numerous layers of very fine-grained material that would be expected to <br />have sealed any significant vertical fracture zones or displacements. However, a small displacement on <br />the order of tens of feet may have occurred without the extensive sealing or smearing of the fracture zone <br />associated with a larger fault. <br />The springs in Flume Gulch (Spring 99-2 and 99-3) were near the southern limits of saturation in the Third <br />White Sandstone aquifer and were also thought to be discharges from this groundwater system. <br />However, TDS and sulfate concentrations measured at these features occurred at lower levels than those <br />documented at Third White Sandstone wells GC-2 and GP-9. Spring 99-2 flowed from a vertical pipe at <br />an old homestead location. Details regarding the installation of the pipe are unknown, however, field <br />measurements showed the pipe extended down roughly 180 feet from the surface. The H seam is known <br />to lie about 30 feet deep at this location. The structural model for the site indicated the pipe at Spring 99- <br />2 extended nearly to the M seam. Based upon this information it is possible the flow from Spring 99-2 <br />4-238b <br />pp? <br />01(24(09