Metallurgy – Oxidized Deposit, Getty North
Metallurgical test work confirmed the amenability of the oxidized copper deposit to leaching. The samples tested were representative of the oxidized zone within the deposit from the surface to a depth of approximately 132 m (435 ft). This confirmed the positive results of the more extensive previous column leach tests conducted on a bulk sample of oxidized ore obtained from the surface of the deposit. Leaching test work on a bulk sample from the Getty North Deposit achieved a copper extraction of 82.5% over a period of 120 days.
Assay results and metallurgical testing confirmed that the oxide zone is from 86% to 96% oxidized and that this mineralization is readily leachable. These tests yielded recoveries from 67.5% to 92% of the total copper, depending on the size of the material, grade, and ratios of sulfide to oxide mineralization. Column tests demonstrated copper recovery of at least 80% is possible within 80-100 days by conventional heap leaching.
Considerable bench scale testing at SGS Lakefield Research, using simulated Continuous Vat Leach methods indicated recoveries similar to those achieved in heap leach tests, but achieved the same results in less than 72 hours compared to 80 – 100 days in column leach tests. This small footprint of the Continuous Vat Leach plant makes it possible to operate year-round regardless (“CVL”)of climatic conditions.
A follow up program in a continuous vat leaching pilot plant at SGS Lakefield Research confirmed recovery of copper in the 75% range in less than 72 hours and that the CVL pilot plant could be scaled-up to a commercial sized plant.
The pilot plant test yielded cathode copper plates that graded 99.97% purity.
Metallurgy -Sulphide Deposit, Getty North
A flotation test on a 27 m (88 ft) composite sample of drill core resulted in a copper concentrate containing 33.8% copper (Cu) at recovery of 96.6%. The concentrate also contained 2.37 g/t gold (Au) and 123 g/t silver (Ag). The test also indicated that additional cleaning of the concentrate could result in a higher-grade concentrate containing 39% Cu while maintaining good recovery rates. These results demonstrate that the copper sulphides respond very favourably to conventional flotation methods.
Types of Copper Mineralization
Types that may be amenable to types of open pit production include:
- LEACH ROCK: Well mineralized rock from the near-surface oxidized copper deposits suitable for processing by either heap leaching or continuous vat leaching.
- DUMP LEACH ROCK: Permanent dump leach of low-grade mixed oxidized and sulphide mineralization.
- MILLING ROCK: Well mineralized rock containing copper sulphides, which can be processed by a conventional flotation concentrator.