Mindoro Resources has reported high gold recoveries from a third round of metallurgical tests of large diameter drill core composites from both oxide and mixed (transitional) oxide and sulphide mineralized material from the Kay Tanda gold-silver prospect in the Philippines.

The results to date indicate that both composites are highly amenable to heap leaching. It appears that most of the gold occurs in the cracks and fissures in the rocks and is readily accessible to the cyanide solution.  Gold dissolution is rapid and high gold recoveries have been obtained from both composites, and with low cyanide consumption.

Kay Tanda is being evaluated for its open-pit, heap-leach potential. Preliminary bottle roll metallurgical test work on reverse circulation cuttings was largely positive. 

A second round of testing was carried out on a small bulk sample of oxidized mineralized material from a pit and gave excellent results. The current test had the objective of evaluating heap leach characteristics of near-surface oxide mineralization, as well as deeper mixed oxide/sulphide (transition) mineralization.

Two series of testwork were completed on the two composites.  The first test was a bottle roll test on composites at 80% passing a sieve at 75um. This test is required to indicate the maximum gold and silver recoveries obtainable and to compare these with the recoveries obtained by heap leach testing. Very high gold and silver recoveries were obtained from both types of mineralized material. From the oxide material 93.4% of the contained gold and 83.7% of the contained silver was leached and recovered in 48 hours.

From the transition material (mixed oxide and sulphides) 88.6% of the gold and 87% of the contained silver was leached. These are unusually high recoveries, especially for the sulphide-containing material.

For the second round of testing, column tests (heap leach tests) were performed on a crush size of minus 12.7mm, which is close to the lower size limit normally used for heap leaching. Gold recovery from the oxide material after 29 days of leaching was 80.3%. Gold recovery from the transition material after 23 days was 80.6%. Silver recoveries are awaited. Both composites are highly amenable to heap leaching.

Because of the encouraging results a further test was started at a very coarse crush size of 50mm, since the coarser the crush, the lower the processing costs. This work is in progress, and results will be reported on completion. Since the transition sample contained a high proportion of sulphide-related mineralization, and leached very well, a test will also be carried out on deeper, entirely sulphide-related gold and silver mineralization as well.

Mindoro management is most encouraged by the results from Kay Tanda to date and considers them a strong basis for further evaluation of the project's economic potential.