Laserfiche WebLink
February 1998 Hayden Gulch Mine • Phase 1 fr 3 Bond Release Apylscation ~ PaRe I1 <br />from the ponds are less than Colorado Water Quality Control Commission <br />• agricultural standazds. In addition, the pond dischazges have met applicable water <br />quality effluent requirements. The HIA also compared constituent concentrations <br />in the pond dischazge versus Wyoming Department of Environmental Quality <br />(WDE~ guidelines for agricultural uses. While the WDEQ guidelines aze not <br />promulgated in Colorado, they aze widely accepted as guidelines for determining <br />use suitability of surface waters and assessing impacts. Constituent concentrations <br />in the pond discharges were less than the WDEQ agricultural use-suitability <br />guidelines which also indicates that the pond dischazges aze not impacting potential <br />agricultural uses in receiving waters. <br />Hydrologic monitoring also indicates that both ponds maintain a permanent pool. <br />In addition to snow-melt runoff, field observations indicate that both ponds receive <br />inflow from seep azeas. DMG personnel identified a seep area (designated at seep <br />SS-1) in 1996 along the northern boundary of the reclaimed topsoil stockpile "A" <br />azea which is tributary to Pond 003. Monitoring by HGCC personnel indicates <br />that this seep could serve as a permanent water supply source for Pond 003. Several <br />seeps azeas also contribute inflow to Pond HG8, namely RSP-2 and RSP-3. <br />HGCC personnel estimate that seepage inflows to Pond HG8 has averaged 50 <br />gallons per minute during base-flow over the last three or four years. <br />Furure maintenance will be performed on the ponds as necessary, however, to date <br />neither Pond 003 nor Pond HG-8 have required any maintenance activities on <br />pond inslopes, embankments, dischazge structures, or for sediment removal. <br />HGCC has inspected both ponds quarterly, results of which have been included in <br />the Annual Hydrology Reports since 1990. The quarterly pond inspection reports <br />indicate that there are no problems with the ponds. In addition, sediment surveys <br />of the ponds conducted in 1992, 1995, and 1997 indicate that there has been little <br />sediment accumulation in the ponds since the disturbed areas were successfully <br />revegetated. [t is expected that these azeas will not experience significant erosion in <br />the future and that there will be little additional sediment accumulation in either <br />pond. As a side benefit of the shrub augmentation program, pond embankments <br />and inslopes will also be protected with elk-proof fence enclosures through Phase <br />III bond release on the shrub enclosures, thus providing additional erosion control. <br />Following Phase II release, the ponds will no longer be required to serve as <br />sedimentation ponds, therefore monitoring for such criteria will no longer be <br />necessary and HGCC. Following approval by DMG, HGCC will submit a request <br />for inactivation of the CDPS permit with the Colorado Department of Public <br />Health and Environment (CDPHE). <br />1.4 REQUIREMENTS OF PHASE III BOND RELEASE <br /> <br />The following information is submitted to meet the requirements for Phase III Bond Release at <br />the Hayden Gulch Mine. Final reclamation at the mine site was completed in 1987 with the <br />exception of two temporary sediment control structures which were reclaimed during 1996. As <br />recommended in the Bond Release Guidelines, the reclaimed sediment control structure sites <br />were included in the vegetation sampling "universe." <br />Montgomery Watson Americas (dba TerraMatrizJ "P.O. Box 7740]8 <br />Steamboat Springs, Colorado 80477 • (970f 8796260 <br />v ~f)nJ1„e J G J Row1 Rdm Aglruw ~Tm \ffis ] 4 J 6aN Rds"Agl~am1 <br />IRA9l J~ <br />