Mindoro Resources has received excellent final results from extensive metallurgical test work from the Kay Tanda gold-silver prospect, Philippines.

The results are for drill core composites for two different crush sizes from both oxide and mixed (transitional) oxide and sulphide mineralized material.

The independent metallurgical consultant noted that "the heap leach results are remarkably good in all cases, with recoveries (of the coarse crush) only about 10% below the maximum gold recovery achievable by grinding to a fine size."

Results indicate both composites are highly amenable to heap leaching. It appears 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. The test had the objective of evaluating heap leach characteristics of near-surface oxide mineralization, as well as deeper mixed oxide/sulphide (transition) mineralization.

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 82.4% and for silver 32%. Silver recoveries are normally low and in this range for heap leach operations. Gold recovery from the transition material after 23 days was 78.3%, and silver 42%. Both composites are highly amenable to heap leaching.

Because of the encouraging results a further test was run at a very coarse crush size of 50mm, since the coarser the crush, the lower the processing costs. Gold recovery from the coarse oxide material after 70 days was still a very high 80.7% and 29% silver. Gold recovery from the transition material after 70 days was 80.1% and for silver 56%. Since the transition sample contained a high proportion of sulphide-related mineralization, and leached very well, a test is also being carried out on deeper, entirely sulphide-related gold and silver mineralization as well.