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Pumping of water with lime to adjust leach pad pH to 11.0 was started on SW-1 pad Cell # 1 on Tuesday, March 8. Wetting of this bone-dry, 5-meter high heap took five days. Break-through of the solution at the bottom of the heap occurred on Sunday night, March 13. Irrigation of SW-1 pad Cell # 2 began on Thursday, March 17. Cyanide solution was applied to both cells on Monday morning, March 21. Combined, Cells # 1 and # 2 contain 97,000 tonnes of ore from the Creston Pit with 1100 oz. contained gold. Pregnant solution containing low concentrations of cyanide started appearing, as expected, three days after first application, on March 24 (72 hrs).
Solution samples are taken several times per day so that precious metals are detected as soon as they appear at the bottom of the heap; the build-up of metal in solutions will be monitored as the gold content increases over the next several months.
Flow from pad Area 789 was stopped so that operators could clean out the old carbon columns. One-half tonne of new carbon has been loaded into each of the five leach columns. The columns are now ready to receive Pregnant Solution. We expect that the leaching will have enough gold in solution to feed the leach columns by March 29. Once the recovery process starts, gold output will gradually increase for many months ahead.
Cell # 4 is in final stacking (receiving ore from the Creston Pit). All four Cells of SW-2 are being stacked to 10m height. Cell # 4 has 79,000 tonnes with 940 oz. contained gold. Pump and flume installations are nearing completion for this heap now. Wetting of Cell # 4 began on March 25. Cyanide will be added when the heap has been wetted for five days.
For the end of March 2011, we expect 175,000 tonnes of fresh ore under leach on the new pads, with 2000 oz. contained gold.
Bruce Thorndycraft
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