2010-02-05_REVISION - C1996083 (8)

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2.04.7 Hydrology Description • In late 2004, the Operator attempted to drill an exploratory hole from a location approximately 2,500 feet northwest of the approved site. Poor hole conditions were encountered immediately. As depth increased, the rock became more fractured and keeping the hole open became virtually impossible. At a depth of 2,612 feet the core bit was permanently stuck in the hole. All down hole assemblies were twisted off and cemented into the hole. The fractured rock is attributed to both the igneous Iron Point intrusion and depth of cover. Similar drilling conditions are expected at potential monitoring well site DH-68. The Operator does not believe it is economically or technically practicable to install down gradient monitoring wells north of the proposed mine plan area. The rugged terrain limits potential drill sites. The only location where a reasonable depth monitoring well could be constructed is in Hubbard Creek but the UDSA-FS does not want the Hubbard Creek road re-opened. Opening the Hubbard Creek road would be problematic because of public opposition, road slope instability and potential flooding. It is highly unlikely the public will use the deep bedrock groundwater located north of the proposed mine plan area. It is simply too expensive to install a domestic or livestock well at such extreme depths. The poor water quality would also discourage public use. The lack of deep bedrock groundwater monitoring data is somewhat mitigated by the highly unlikely public use of the water. • Based on the above discussion, the Operator requests relief from the installation of a down gradient monitoring well for the northwestern mining districts contemplated by PR-10, PR-11 and TR-65. (b) The subsurface hydrologic regime may be divided into four discrete subsystems: 1) the alluvium and terrace deposits associated with the North Fork of the Gunnison River; 2) localized deposits of alluvium-colluvium within the Hubbard Creek, and Terror Creek area; 3) groundwater occurrences within the Mesaverde Formation; and 4) colluvial discharges associated with soil moisture storage in Steven's Draw, C-Gulch and at the head of Freeman, Sheep Corral and Dove Gulches. North Fork of the Gunnison River Alluvium Alluvial fill associated with the North Fork of the Gunnison River and tributary drainages (Terror Creek) have been extensively developed for domestic and agricultural water sources. For a discussion of Alluvial Valley Floors, see section 2.06.8. The State Engineer's records depict 3 registered wells completed within the alluvium located in Sections 14, and 15., T.13 S., R.92 W., 6th P.M. (Bowie No. 1 Mine Area) These wells range from 14 feet to 77 feet deep and typically produce water from 12 feet. The well yield ranges from 5 gpm to 120 gpm with average yields of • approximately 17 gpm. Water quality is highly variable within the alluvial fill. Most wells completed near the river sustain quality adequate for human consumption; however, the higher sulfate and total dissolved solids values are TR-65 2.04 - 25 - 02/10