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RULE 2 - PERNUTS <br />2.05.3 -1\12 Mine Plan Map. the location of the five identified golden ea��le nests are in the proximity <br />of the initial ,atcroads developed by continuous miner methods. PSCM will consult With CPW <br />prior to initiation of underground ininniO activities with regard to initloation Of potential Subsidence <br />affects specific to the PSCNI area. Consultation will OCCUr prior to March of year 2 of operation at <br />PSC'NI. This year is based on the anticipated schedule proposed In Section 2.05.3 Operation Plan. <br />Greater Sandhill Crane Protection Measure (GSCPNI). <br />To prevent or limit impacts to an} nesting greater sandhill cranes that are discovered on or �\ithin <br />one mile of the PSCM surface disturbance area PSCM «ill: <br />GSCPN1 1 - If possible. locate Surface disturbance areas and access roads at least 0.5 mile (0.8 knl) <br />from all known nest sites and nesting habitat (see Table 2.04.11 -T5 in Section 2.04.11 for all <br />(Treater sandhill crane nest locations). <br />Stream Depletion Calculations — Windy Gap Process <br />PSCM has evaluated plans for water use at the PSCM in order to develop a simplified water balance <br />and resultant estimate of'potential stream depletion evaluation under the Windy Gap process. Major <br />assumptions used include the following: <br />• The lllajorlty of mule inflows are froin deep bedrock formations that are not contributory to <br />stream flow in the Yampa River. <br />S • Mine lnflox\s are based on the inaxilnU1n amount of «atcr predicted at 26 months during the <br />permit terns (see Section 2.05.6(3)(iii)). <br />• The SUrfaCe moisture loss is based on a ina\lniurn estimate of Surface moisture 01 3.0 <br />percent for 2 million tons per year of coal production. <br />• Water use for dust control at surface facilities. including haul roads, assumes 20,000 gallons <br />per day and one -half the amount is evaporated. <br />• Evaporation was calculated from Ponds 002, 003. 004. PECOCO, both coal stockpile sumps <br />and both portal sumps using an annual lake evaporation rate for Hayden, Colorado of 2.206 <br />feet per year. <br />The amount of water that could be depleted from the overlying alluvium along Grassy and Little <br />Grassy Creeks was calculated as follows: <br />Vertical (normal to the bedrock bedding planes) flow of groundwater from the alluvium along <br />Grassy and Little Grassy Creeks to the mine workings could occur while the mine workings below <br />the alluvium are dewatered and drawdown is present in the bedrock between the mine and the <br />alluvium. A steady -state flow groundwater rate can be estimated using the following equation <br />(Freeze and Cherry, 1979): <br />Q = K A (/ — /ai) /L <br />where: Q = volumetric flow rate <br />K = vertical hydraulic conductivity <br />A = cross - sectional area of flow (area of alluvium in contact with bedrock) <br />h, = head in mined area <br />Midterm Review 2.05 -67 Revision 04/2013 <br />