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Exhibit 71 Hydrologic Characterization South of the Divide Area and Monitoring Plan 18 <br />4.3.1 Upper North Fork Drainage Basin Surface Water Monitoring Stations <br />4.3.1.1 Deep Creek <br />Deep Creek is a perennial stream drainage that drains the Box Canyon mine panel area and the east side <br />of the SOD and West Flatiron azeas. The Upper Deep Creek monitoring station is located up-gradient of <br />the Box Canyon mine panel area (mine panels 14 - 17 and 22 - 24) and the West Flatiron area. The <br />Lower Deep Creek monitoring station is located down-gradient of the SOD area and is directly east of the <br />Box Canyon panels (Map 1). The flow monitoring at the Deep Creek monitoring sites will be changed <br />from continuous flow recording to instantaneous recording three times a year, in 2006. This change is <br />being made for two reasons: mining in this area is nearly complete and the Deep Creek stream channel is <br />highly variable, resulting in continuous flow data that are unreliable and do not represent actual <br />conditions. <br />4.3.1.2 Box Canvon <br />Box Canyon is an ephemeral stream drainage. The upper reach of the drainage is typically dry and the <br />lower reach of the drainage only flows during storm events and during the spring months in above <br />average precipitation years. The Box Canyon monitoring station is located at the mouth of the drainage <br />and was established to monitor the area down-gradient of the Box Canyon panel area (Map 1). <br />4.3.1.3 North Fork Upper <br />The North Fork of the Gunnison River is a major perennial stream that drains the northern mine azea. The <br />North Fork Upper monitoring station is located up-gradient of the WEM facilities area and up-gradient of <br />the WEM discharge points (Map 1). The underground mine water discharge flows into Sylvester Gulch <br />then into the North Fork of the Gunnison River. The mine surface water runoff is treated and routed to <br />holding ponds and is then discharged to the North Fork of the Gunnison River, if necessary. All of the <br />WEM water dischazge occurs between the North Fork Upper and North Fork Lower monitoring stations. <br />4.3.1.4 Svlvester Gulch <br />Sylvester Gulch is an ephemeral stream that drains the north-central WEM area. All the active surface <br />facilities of the mine are located within the Sylvester Gulch drainage basin area including: the main road <br />to the mine facilities from Highway 133, the mine waste dump, the mine shop and offices, the mine <br />portal, the mine ventilation shafts, and the mine water discharge facility. The three monitoring sites in <br />Sylvester Gulch: Upper, Middle and Lower Sylvester Gulch (Map 1), aze designed to monitor areas up- <br />gradient of the mine surface facilities area, areas down-gradient of the mine water discharge point and <br />mine facilities, and areas down-gradient ofthe mine spoils dump, respectively. <br />`J <br />Apri12006 AydroGeo, lnc <br />