Laserfiche WebLink
8.0 PRECIOUS METALS RECOVERY FACILITY <br />The existing precious metals recovery facility is located on the south side of the AGVLF and <br />designated as the AGADR Facility. A new SGADR complex will be constructed at the SGVLF <br />to provide gold recovery for pregnant solution from the SGVLF. Both facilities are shown on <br />Drawing C -4 with additional information provided in the following discussions. <br />The new SGADR facility will process pregnant solutions from the SGVLF in the same manner <br />as the existing AGADR at the AGVLF. The ADRs receive the pregnant solution from the VLFs, <br />remove the gold in the solution by adsorption onto activated carbon, strip the gold from the <br />activated carbon to create a concentrated gold solution (desorption), and recover the gold in an <br />electrowinning circuit. Each step is explained in more detail in the following discussion. <br />Pregnant solution is pumped from the PSSAs to the ADR facilities. The pregnant solution is <br />pumped to a series of carbon columns The number of carbon columns are different for the <br />SGADR and the AGADR as explained in Sections 8.1 and 8.2, respectively. The carbon <br />columns consist of multiple tanks in series that are partially filled with activated carbon. The <br />pregnant solution flows by gravity through these tanks and the gold in the solution adsorbs (or <br />attaches to the surface) of the activated carbon. The carbon is advanced from the lowest (last) <br />tank in the series to the highest (first) tank and is then pumped to the stripping circuit. The <br />carbon at this point is referred to as loaded carbon. <br />After the gold is removed from the solution, that solution known as "barren solution" is pumped <br />through filters to remove any small carbon particles and then to a barren solution storage tank. <br />From the barren solution storage tank, the amount of sodium cyanide and pH is adjusted in the <br />solution and the solution is recycled or pumped to each respective VLF where it starts the <br />process over by percolating through the ore material to again become "pregnant solution" or <br />solution laden with gold. Note that both ADR facilities operate at an average 16,000 gpm <br />throughput. The loaded carbon is washed with a dilute hydrochloric acid solution to remove <br />scale and then transferred to a stripping vessel. The stripping vessel uses a solution of hot water, <br />sodium hydroxide, and sodium cyanide to strip the gold from the activated carbon creating a <br />concentrated gold solution. <br />The dilute hydrochloric acid solution is drained from the acid wash tank and the solution is <br />neutralized with sodium hydroxide in a neutralization tank and returned to the VLF in the barren <br />solution. The stripped carbon is sent back to the carbon columns for reuse or sent to the carbon <br />regeneration kiln for re- activation and then back to the carbon columns. <br />Cripple Creek & Victor Gold Mining Company <br />Cresson Project Mine Life Extension 2 <br />8 -1 <br />