REP06591 - Laserfiche WebLink

Home Browse Search

Febn,ary 1999 HG Cml Gm+ltary " ] 998 A>eata/ Redmaxuun Relent ~ Paee f 4.0 HYDROLOGIC MONITORING • 4.1 SURFACE WATER Per the hydrologic monitoring requirements of the existing, valid Permit, HGCC monitors two stream surface water locations, LHG (Lower Hayden Gulch -Hayden Gulch downstream of the mine area at the pemtit boundary) and UHG (Upper Hayden Gulch -Hayden Gulch upstream of the mine area). Both locations have been monitored on a semi-annual basis since 1985. Drawing 2, Hydrologic Monitoring Sites, shows the locations of the surface water monitoring stations. Discharges from sediment ponds 003 and HG-8 are regulated under a National Pollutant Discharge Elimination System (NPDES) pemz;t. Pond outflows are shown on Drawing 2. In addition, HGCC is required to monitor six spoil springs (reclamation spoil spring [RSP]-1 through RSP-6) on an annual basis between April 1 and May 15. Results of the seep monitoring program are summarized in Settion 5.0. In anticipation of the Phase II/Phase III bond release application, HGCC initiated an expanded surface water monitoring program during 1996 and added four monitoring locations to the surface water monitoring network. Drawing 2, Hydrologic Monitoring Sites, also shows the locations of the supplemental program surface water monitoring stations. The four supplemental sites are: • Site HG-15 • Site HG-Trib • Site WF-1 • • Site WF-2 Monitoring stte HG-1S is located on Hayden Gulch approximately 2,000 feet upstream of the confluence with the Williams Fork River. This monitoring station is about 1.5 miles downstream of the mine permit boundary. Site HG-Trib is located on a minor Hayden Gulch tributary. Surface water monitoring site WF-1 is located on the Williams Fork River downstream of Hayden Gulch. Site WF-2 is located on the Williams Fork River upstream of Hayden Gulch. Monitoring station WF-1 was not sampled during the fall 1998 monitoring event. HGCC was unable to contact the landowner for site access permission, consequently, an alternative downstream site identified as WF-P was sampled. Site WF-P is located on the Williams Fork River neaz Pagoda, Colorado and is between two and three miles downstream of WF-1. Water quality data from 1998 indicates that constituent concentrations from surface water monitoring stations were generally within the range of previously observed values, with the exception of total concentrations of aluminum, iron and manganese. On May 7, the two Williams Fork sites (WF-1 and WF-2) had total concentrations of aluminum, iron and manganese that were higher than previotsly reported values. Total suspended solids (I'SS) concentrations were also higher than previously reported values. The elevated total aluminum, iron and manganese concentrations were probably related to the elevated TSS concentrations. Similar total metals concentrations were reported for UHG, HG-Trib and HG-15 in the November 24 samples. TSS concentrations for these samples were also elevated and the higher total metals concentrations can probably be attributed to the higher TSS concentrations. Results of field parameter measurements and surface water sample laboratory analyses for the 1998 surface water monitoring program are included in Exhibit 3, Surface Water and Groundwater Monitoring Data. • Morugnery Watan "!?O. Boz 774018 "Str~vnlaat Spiatys, Cdora~o 80477 "(970J 879-6160 v!~w»u.dxy~~iwavra+n.r e~--.~a.~ )/~N9 b