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STOCK POND T -5 <br />PERMANENT POND DEMONSTRATION <br />In 2004, SCC constructed a stock pond in the middle portion of a permanent channel in the A Pit <br />reclamation and, along with the land owner, believes that the pond should remain permanent. The <br />location of this stock pond T -5 is shown on Exhibit 20 -2, Postmining Topography Map. The purpose <br />of this evaluation is to demonstrate that Stock Pond T -5 meets the design criteria specified in Rule <br />4.05.9 for permanent impoundments. <br />Water Quality <br />This stock pond is located on a permanent channel. There is no indication that the runoff contains <br />potentially acid or toxic forming material that could adversely impact surface water quality. Results of <br />the water sample analyses are attached. The analysis indicates that the water is suitable for the <br />approved post mine land use that includes livestock grazing and wildlife habitat. <br />Water Persistence <br />Observations indicate that this pond holds water year - round. <br />Accessibility <br />This pond is easily accessible to livestock and wildlife. There are no drop offs or excessively steep <br />slopes around the edges of this pond. <br />Capacity <br />The water storage capacity for T -5 is 0.6 ac. ft. Since the capacity is under the 2 ac. ft. limit, the State <br />Engineer's office does not need to review the permanency request and the pond should not have any <br />significant effect on downstream users. A general stability analysis was conducted for stock ponds <br />based on the construction methods and material characteristics. A predicted Factor of Safety of 1.56 <br />was calculated by this analysis. This stability analysis is contained in Attachment 13 -11 and a <br />summary copy is attached. <br />Pond Dimensions <br />The dimensions and capacity for this stock pond are shown in the PAP on Exhibit 13- 27.T5, Stock <br />Pond T -5 Survey. As shown on the as-built drawing, the embankment is 4 feet in height as measured <br />«�.. tlx: i.n e-rt c* the spiEl -3-y; however the pond was excavated to provide fill for <br />the cmbankment. T ncrefore the embankment is less than 5 feet in height from the upstream natural toe <br />of the embankment to the invert of the spil!NNay. 1 tic; combined si%pe of all th:, cmbaa -n nAs do not <br />exceed 5V:1H with no slopes greater than 2H:1V. <br />MR -76 T -5.1 Revised 12/13 <br />