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Direct disturbance of surface flow channels may occur through temporary disturbance for construction activities <br />or long -term disturbance for road or railroad crossings. Examples would be the mine road and railroad crossings <br />of Foidel and Fish Creeks. <br />The greatest potential impact to surface flows from this operation is the discharge of mine inflow water. Ground <br />water that flows into the mine is collected in sumps and pumped to the surface, where it is normally diverted to <br />sedimentation ponds or treatment facilities. The potential also exists for direct discharge to area drainages. The <br />relatively continuous inflows discharged to Foidel Creek snake up a significant proportion of the total creek <br />flow, particularly during the period of low flow from September to February. Due to its higher in- stream flows, <br />changes to Fish Creek water quality from discharges from Site 115 will generally be less than those to Foidel <br />Creek. <br />Detention of surface runoff in sedimentation ponds decreases peak flow rates, and reduces the amount of water <br />available downstream. Diversions of overland flow will deprive small areas of water, but will not reduce the <br />amount of water downstream. <br />The quality of surface and ground water could possibly be affected by water handling and treatment methods <br />under the planned operations of the Foidel Creek Mine. Impacts of mining on water quality can be measured by <br />analyzing the data of indicator parameters such as conductivity, total dissolved solids (TDS), total suspended <br />solids (TSS), sodium adsorption ration (SAR), and pH. Mining activities in the permit area will create changes <br />in surface water quality. Mining practices such as removing and stockpiling topsoil, clearing vegetation, road <br />construction, and vehicular travel in disturbed areas may result in the potential for increased erosion. TSS <br />concentrations of streams should not increase because flows from disturbed and reclaimed areas will be treated <br />in sedimentation ponds to meet NPDES effluent limits. The effects of leaching in exposed spoil and waste rock <br />plies, detention of water in sedimentation ponds, and pumping water out of pits and underground mine workings <br />have the potential to increase TDS concentrations and change ionic composition of surface waters. <br />The ongoing and planned underground mining activities have the potential of creating changes in the existing <br />surface water quantity in terms of runoff flows and flow rates including changes in peak flows and low flow <br />conditions. Likewise, these underground mining activities have the potential of producing changes in the <br />existing surface water quality in teens of conductivity, total dissolved solids (TDS), total suspended solids <br />(TSS), ionic composition, sodium adsorption ratio (SAR), pH, and trace metals with iron and manganese, the <br />primary indicators. Water quality impacts will be addressed for all seasonal conditions including both high and <br />low flow conditions. <br />The underground mining and related activities that have the potential of impacting surface water flows and <br />water quality are described below along with an assessment of the nature and magnitude of potential impact. <br />The primary surface water impact will result from the discharge to Foidel Creek and Fish Creek of mine inflows <br />that are collected in sumps and pumped to sedimentation ponds and settling ponds for treatment prior to release <br />or discharged directly to these drainages <br />Imoacts of Direct Disturbance of Surface Flow Channels <br />Direct disturbance of surface flow channels may occur either when temporary construction activities require a <br />stream crossing for installation of pipelines or other utilities, or for long -term road or railroad crossings. In both <br />cases, normal streamflows will not be interrupted and any stream channel disturbance will be mitigated through <br />reconstruction of the natural stream channel and floodplain configuration. <br />Normally, any disturbance in stream channel areas will occur during low -flow periods to minimize disruption of <br />flow. If flow characteristics of the affected channel are ephemeral or intermittent, it may be possible to <br />complete work in the stream channel when there is little or no flow. If any significant flow is occurring during <br />the construction period, flows will be temporarily diverted around the disturbance area during construction using <br />a pump(s) and pipeline. Normal flow will be restored, once construction is completed and the affected channel <br />areas restored. <br />TR13 -83 2.05 -150 11 /03 /14 <br />