Preliminary metallurgical results for the potential underground high-grade gold mineralization extending east from the proposed open pit, have been received and show excellent extraction of gold using standard processing techniques. New composites were created based on the two (2) predominant gold bearing lithologies in that zone: felsic gneiss and pegmatite. The average head grades were 6.47 g/t Au and 9.52 g/t Au respectively. Metallurgical response of these composites to gravity and whole ore leach (WOL) were determined.
Gravity for the high-grade composites responded extremely well with an average of 60% gold extraction. Leaching was performed at two different grinds ~100 microns and ~60 microns, and in duplicate.
Completed work for the Preliminary Economic Assessment ("PEA") includes metallurgical and comminution testing on the lower-grade zone (open pit). Metallurgical tests include gold extraction from gravity, flotation and leach from different geo-domain composites, fine regrind, settling, and In-Line Reactor (ILR) test work. The comminution test program includes: Drop-Weight Test (DWT), SAG Mill Comminution Test (SMC), Bond Ball Mill Work Index (BWi), Rod Mill Work Index (RWi), Abrasion Index (Ai), Unconfined Compression Test (UCS) and Low Energy Impact Test. These results are providing the input data to perform a series of trade-off studies, in particular to compare the two main process options (gravity, whole ore leach vs. gravity, flotation and leach of flotation residues and reground flotation concentrate). For the low-grade zone, the flotation process route provides slightly better gold recoveries. Final results will be released upon completion.
Mr. Michael Petrina, Chief Operating Officer of Probe, states: "These metallurgical results from the high-grade zone are very encouraging and are not surprising given the amount of visible gold observed in drill cores. These results show an overall increase in gold extraction response. The potential for a simplified flowsheet, where no flotation/regrind option would be required has very positive implications in a potential development scenario. Borden Gold continues to improve in all areas".
The metallurgical testing was carried out under the supervision of BBA Inc. and was conducted by SGS Mineral Services (Lakefield) and Process Research Ortech Inc. (Mississauga). The contents of the above have been approved by Qualified Person Mr. Jacques McMullen, P.Eng of BBA Inc., independent consultants to Probe.
