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SENECAIIPERMANENT • STOCK POND EVALUATION Seneca Coal Company (SCC) has constmcted 21 temporary stock tanks in the reclaim azeas at the Seneca II mine. SCC has reviewed the need and design for each of these stmctures to determine whether they should be retained as permanent oz be reclaimed. The results of this review indicate that a number of the structures should be reclaimed. STOCK PONDS TO BE RETAINED STOCK PONDS TO BE AS PERMANENT STRUCTURES RECLAIMED T-4, T-8, T-16, T-17, T-20, T-26, T-28, T-29, T-1, T-2, T-3, T-5, T-6, T-7, T-9, T-10, T-11, T-12, T-30, T-31, T-32, T-33 T-13, T-15, T-25, The purpose of this evaluation is to demonstrate that existing stock ponds T4, T8, T16, T17, T2Q T26, T28, T29, T3Q T31, T32, and T33 meet the design criteria specified in the Regulations of the Colorado Mined Land Reclamation Boazd (Ru]e 4.05.9) for permanent impoundments. WATER QUALITY Water contained in the proposed stock ponds will originate as runoff from the Seneca II redamadon azeas. There has been no indication that neither the spofls nor replaced topsoil contain potentially acid or tonic forming material that could adversely impact surface water quality. In addition, water sampling in the azea has not indicated any water quality problems. Therefore, Seneca does not antiapate any problems with water quality. Water sampling conducted during the bond release period will be used to • confirm this. WATER PERSISTANCE Based on quarterly pond inspections all the ponds that will be left as permanent stock ponds contain water most of the spring and summer seasons. Seneca will continue to inspect the stock ponds on a regulaz basis, if inspections show that any ponds remains dry for three (3) years straight they will be reclaimed. ACCESSIBILITY All the stock ponds are easily accessible to livestock and wildlife. CAPACITIES The capacities of all the permanent stock ponds aze less than two aue-feet, therefore there should not be any significant effect on down stream users. POSTMINE LAND USE The proposed/approved pos[mine land use for [he Seneca II mine area is primarily for livestock grazing and secondarily as wildlife habitat. The permanent stock ponds will enhance both pos[mine land uses. POND DIMENSIONS • The dimensions and capacity of permanent stock ponds are shown on the attached stock pond as-built drawings. As shown on the stock pond as-built drawings, all the embankments are less than 5 feet in height as measured from the upstream toe of the dam to the invert of the emergenry spillway. The combined slope of all the embankments is less than SH:1V with no slopes greater than 2H:1V. All the capacities ate less than 2 ac-ft. All the stock ponds have emergenry spillways that consist of a single open channel. None of them have a principal spillway or dewatering pipe.