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The Leadville Mill M1990-057 <br /> EXHIBIT C—MILL PLAN <br /> Page 4-6 <br /> TABLE 4-3: GRINDING PERFORMANCE CRITERIA <br /> Equipment Performance Value Unit <br /> Fine Ore Bin <br /> Capacity 200 stpd <br /> Ball Mill <br /> F80 12,500 micron <br /> P80 104 micron <br /> B W i 15.45 - <br /> Operating Hours 20 hr/day <br /> Rate(8-hr/day) 18.58 hr/day <br /> Rate(16-hr/day) 11.9 Hr/day <br /> Horsepower 200-250 hp <br /> Horsepower. Max 300 hp <br /> Ball Mill Sump <br /> Flowrate 600 gpm <br /> Residue Time 4 min <br /> Sump Capacity(@90% 2,670 gal <br /> capacity) <br /> Cyclone <br /> Operating Units 2 units <br /> Standby Units 1 units <br /> Flowrate,total 600 gpm <br /> Flowrate, per unit 300 gpm <br /> Thickener <br /> Feed 25% solids <br /> Unit Area 0.12 ftz/tpd <br /> Underflow 40 solids <br /> Diameter 10 feet <br /> LEACH & MERRILL CROWE CIRCUIT <br /> Dissolution of gold (Au) and siler (Ag) using cyanide (CN) was developed in the late- <br /> 19th century. Dissolution occurs as: <br /> 4Au + 8NaCN + 02 + 21-120 --> 4NaAu(CN)2 +4NaOH <br /> Merrill Crowe is a process which uses zinc to precipitate Au and Ag from cyanide <br /> solution using direct reduction reactions as: <br /> 2Au(CN)2 + Zn --> 2Au + Zn(CI)4-2 <br /> 2Au(CN)2 + Zn + 30H-1 --> 2Au + HZn02-1 + CN-1 + H2O <br /> Trommel and crusher circuit equipment performance criteria are shown in Table 4-4. <br />