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Rrrle 1.05 TABLE 2.05-3 SEDfMENT POND CHARACTERISTICS Identification Outfall Location Drainage Runoff Sediment Storage No. Area Volume Volume Capacity' !acres! !acre-feet!' !acre-(earl' !acre-feet) 001 001 Explosives storage area 3.87 0.0 0.0 0.20/0.20 002 002 Landfill area 7.25 0.0 0.0 0.41 /0.41 003• 003 Shoploffice area 25.16 0.01 0.0 1.73/1.73 HG-8• 004 Mine area 320 2.26 0.01 22.1/>17 1. Volumes from 8/20!91 SEDCAD modeling except HG-8, which are hom 4/5/96 SEDCAD modeling; all volumes except HG-8, 24-hour storm event 12.3 inches) 2. First number =design capacity (water + sediment!; second number =availa ble capacity on 7/1/961/5/94 3. Volume from 10-year, 24-hour storm event 11.8 inches) • Ponds approved as permanent impoundments Design standards and performance specifications for the permanent impoundments and drainage ditches are discussed in Section 4.05 of this document. Overburden During reclamation, a focal of 983,000 cubic yards of overburden were backfilled from two . overburden stockpiles into the pit. Approximately 638,000 yards of this material came from the "permanent" overburden dump and 345,000 yards from a "temporary" stockpile. Table 2.05-4 summarizes volumes of overburden moved during final mine closure and reclamation operations. Equipment used for mine backfilling were TS 24 scrapers and D-9 dozers. As previously noted, approximately 7,500,000 yards of excess overburden was placed in a permanent spoil pile located north of the pit area. • TABLE 2.05 OVERBURDEN BALANCE SHEET 1985-1986 Volume Removed Ilcyl From Volume Backfilled To 868,000 cut 12 868,000 cut 11 1,258,000 cut 13 261,000 cut 11 997,000 cut 12 1,504,000 cut 14 345,000 "temp." stockpile 197,000 cut 12 786,000 cut 13 176,000 cut 14 842,000 cut 15 713,000 cut 14 129,000 cut 15 239,000 cut i6 239,000 cut 15 345,000 "Temporary" 138,000 cut 15 stockpile 207,000 cut 18 5,056,000 5.056,000 'tR-6 3 q ~y~y 6 Il~~s~9~ 2.05-5 SuBrarTfAL.