Laserfiche WebLink
1.3.2 Wetlands <br /> Wetlands on the Cross Mine property are primarily associated with Coon Track Creek, which is a narrow <br /> and well-defined channel that flows through the length of the property and drains the entire Cross Mine <br /> area watershed. Coon Track Creek is a tributary of Beaver Creek, which flows into Middle Boulder Creek <br /> above Barker Reservoir. Coon Track Creek exhibits steady low flows year-round below the mine site due <br /> to discharges from the Cross and Caribou mines, with high flows during snowmelt runoff. <br /> Waters of the U.S., including associated wetlands,were surveyed within the proposed site boundary and <br /> plotted by a Professional Wetland Scientist for Walsh Environmental using a Trimble XT(hand-held GPS <br /> unit with ESRI ARC Pad mobile mapping software) and total 1.94-acres(84,506 sq. ft.).A Jurisdictional <br /> Determination was approved by US Army Corps of Engineer(USACE) on February 7, 2008. GIR is in the <br /> process of mapping the wetlands around Coon Track Creek; however,this will not occur until early <br /> summer of 2021. GIR will provide the new Jurisdictional Determination and the approval letter when <br /> completed. GIR received a letter of USACE No Permit Required Verification from the USACE stating that <br /> a 404 permit is not required for the road over the wetlands and creek. This letter is provided in <br /> Attachment II (USACE 2021). <br /> 1.3.3 Surface Water Quality <br /> Water quality varies throughout the Boulder Creek Watershed, but is generally best in higher elevations <br /> where there is less human activity. Water quality declines downstream because of increased human <br /> impact and longer contact time with soil and rock. Surface water from snowmelt and groundwater that <br /> flowed through unreactive geology generally has low concentrations of dissolved solids and minerals. <br /> Overall,the chemistry of Boulder Creek at higher elevations is consistent with weathering of the <br /> crystalline rocks and historical mining does not appear to have contributed to metal loading in the creek. <br /> Analytical results show that metal concentrations (arsenic, cadmium, chromium, copper, lead, nickel, <br /> silver, and zinc) are all below 1 mg/L. Low sulfate concentrations could be derived from minor <br /> dissolution of pyrite (Verplank et al.2000). <br /> The waste rock is primarily composed of gneiss and quartz monzonite.These materials have been <br /> analyzed for leachability and acid production by DRMS-approved methods.The results of the analyses <br /> demonstrated the materials are non-acid producing and non-metals leaching. Due to the nature of the <br /> waste rock generated by mining operations, significant impact to ground water quality is not expected. <br /> Coon Track Creek is characterized by steep side slopes and a rocky channel bottom. In the upper and <br /> mid-reaches of the creek,the presence of wetland habitat is nominal and only extends beyond the <br /> banks in a few isolated, low-lying areas. Five man-made, plastic-lined ponds flank the north and west <br /> sides of the mining complex.The pond fringes are devoid of vegetation. Below the mine structures,the <br /> creek meanders along a narrow ravine before exiting the property through a Boulder County maintained <br /> culvert under the Cross Mine access road. Wetland habitat associated with the downstream reaches is <br /> limited to the riparian corridor and to a wet meadow area on the north bank that is situated just east of <br /> Pond #2 and extends into the adjacent aspen woodland. <br /> 14 <br />