Wind Mountain Technical Presentation from Northwest Mining Association Conference December 2011
Fortune River drilled 27 holes (25,965' or 7,914m) over a two-year period, confirming select areas of in-place resource and, in early 2008, discovering a new area of mineralization referred to as the DeepMin target. This new mineralization is located under alluvial cover west of the Wind open pit and in-house estimates (not 43-101 compliant) suggest the mineralization is similar in size and grade to the original deposit. DeepMin is open to the west, south, and at depth, but ranges from strongly oxidized to completely un-oxidized.
An independent 43-101 Technical Report completed in late 2007, prior to discovery of the DeepMin mineralization, estimated a Measured plus Indicated Resource of 406,000 ounces of gold averaging 0.411g/t above a cut-off of 0.257g/t Au, plus an Inferred Resource of 92,000 ounces of gold averaging 0.308g/t Au at the same cut off. Surrounding this remaining resource, but not included as resource, is a large halo of material averaging 0.2g/t Au. Ongoing work by Fortune River suggests this material can be up-graded by either sieving off larger size fractions or by dump loading.
Up-grading can occur because sinter and early silicified rock (prior to main ore stage) was impermeable to gold-mineralizing fluids, except where highly broken; thus, large blocks of such rock have low gold concentrations and exhibit very poor leach recovery. Fortune River's sampling of AMAX's ‘waste' dumps has verified that such up-grading occurred within the upper portions of the dumps as the larger boulders rolled off the dumps and left higher grade material behind. The up-graded portions of the historic waste dumps should contain very profitable ounces because of favorable metallurgical characteristics and very low mining costs, potentially providing significant early cash flow. Verification of this up-grading process may affect how material with sub-ore grades, which would normally be considered waste, can be handled during new mining; this is significant because of the large amount of near-surface sub-ore material delineated to date.
Large un-drilled and under-drilled areas on the property have been identified that could contain additional shallow deposits. Past drilling in some of these areas has intersected mineralization at shallow depths with grades similar to the existing resource. The focus of Fortune River's work to date, however, has been to explore for bonanza-grade ‘feeders' beneath the disseminated mineralization.
The company completed a bulk sampling program with column-leach results from dump material, demonstrates attractive leaching characteristics, with 61% recovery for gold and 15% recovery for silver, low cyanide consumption (0.46 kg NaCN/mt) and low requirements for lime (1.4 kg/mt). The test was performed over a period of 134 days on -150mm (-6 inch) material, which comprises 95% of the original 20-tonne sample.
