Apr 10 2014
Northern Vertex Mining Corp. (the "Company") is pleased to provide a further update on the Company's Phase I - Pilot Plant operations, the first phase of a three phase project development plan for the reactivation of the Moss Mine Gold-Silver project located in Mohave County, Arizona, USA.
Highlights as of April 6, 2014 are as follows:
- Gold recovery rates on Cells 1-5 are 80.51% after an average of 192 days, now significantly exceeding expectations indicated in the Company's Preliminary Economic Assessment ("PEA").
- Gold recovery rates in Cells 6A and 6B are 55.87% after 96 days. These cells are being utilized to further broaden the Company's leach experience on different crush sizes of mineralization and different agglomeration rates.
- Gold dore produced amounts to 3,389 ounces of gold and 13,211 ounces of silver. The average price of gold received to date is $1255.36/ounce. The average silver price received to date is $20.39/ounce. A further 600 ounces of gold and 12,000 ounces of silver are anticipated to be recovered over the next several months.
Dick Whittington, President & CEO Northern Vertex Mining Corp., states, "Gold recoveries are continuing to exceed our expectations and are now well above those assumed in the PEA. The Pilot Plant has enabled us to continue to significantly de-risk the Moss Mine project by stress testing the physical attributes and leach kinetics of our mineralization in an operating environment, something that is pretty unique for a company at our stage of development. This will stand us in good stead as we move towards Phase II and commercial production."
Phase I - Pilot Plant: Metallurgical Findings as at April 6, 2014
Cells 1-5: Cells 1-5 consisting of 81,630 tonnes of mineralized material containing 3656.7 ounces of gold and 36,912 ounces of silver were under continued leaching with results as follows:
- Recovery rates to date are 80.51%.
- Leaching times vary from 218 days for cell 1 to 163 days for cell 5 with average leaching time at 192 days.
- Gold recovery attributed to cells 1 thru 5 totals 2944.4 ounces yielding a pre-completion recovery of 80.51% Au. (Preliminary Economic Assessment is based on 75% gold recovery after 9 months).
- Gold is still being recovered from all 5 cells (i.e. the recovery curve is not yet horizontal).
- Silver recoveries are at 38.72% as gold is being preferentially adsorbed onto the carbon resulting in high silver recycling values in the leach solution.
The material under leach in Cells 1-5 is considered reflective of mineralized material to be crushed, agglomerated and leached going forward. Standard protocols for crushing (95% minus 1/4 inch) were exceeded (+98% was achieved) while cement additions for agglomeration (4 lbs/ton) were met. Three different heap bench heights were tested - 27', 30' and 35' - and both the physical and chemical results of the leach pad continued to exceed expectations at the higher bench heights.
Cells 6A and 6B: Cell 6A (crushed to-1/4 inch, agglomerated and stacked but not subjected to leach solution for 48 days) and Cell 6B (-1 inch, not agglomerated) were first treated with leach solution on January 1, 2014 and consist of 12,730 tonnes containing 702.6 ounces of gold and 8,185 ounces of silver with results as follows:
- Recovery rate for gold to April 6 is 55.87%
- Leaching times of 96 days for both cells apply
- Gold recovery rates are slower than Cells 1-5 but remain in line with laboratory expectations
- Silver recoveries are 12.44%
The material under leach in Cells 6A and 6B is from a wider area of the Phase I pit and is being used to test recoveries from varying crush sizes, further enhancing the contribution and value of the pilot plant phase to the Company's understanding of the leachability of the Moss Mine mineralization as a whole. Different operating and agglomeration protocols were also used.
In the last week of March, a further field test was initiated. An additional 2,964 tonnes grading 0.593 g/t Au and 6.13 g/t Ag of previously crushed, but not agglomerated, -7/16 inch material was added to the heap. On site mini-column testing of this material indicated that 70% recovery could be achieved with adequate percolation rates.
Gold recovery in all cells is anticipated to continue until mid-year.
Gold Processing and Dore Production
Gold dore produced to date amounts to 3,389 ounces of gold and 13,211ounces of silver. The average price received to date is $1255.36 per ounce. The average silver price received to date is $20.39/ounce. The process of loading gold and silver onto activated charcoal on site and shipping to gold processing facilities continues. A further 600 ounces of gold and 12,000 ounces of silver are anticipated to be recovered, processed into dore and sold over the next several months.
Ongoing Activities:
The Company's operations currently focus solely on the leaching of gold from the pilot plant leach pad operation. The Company continues to exercise fiscal responsibility and has reduced costs, corporately and in the field, in order to preserve cash in the current market environment. Work on the Feasibility Study continues with the immediate focus on reviewing and enhancing the Company's block model based on the most recent drilling (see News Release dated October 17, 2013) and additional geological information made available as a result of the Company's Phase I - Pilot Plant operations.
Qualified Persons:
The foregoing technical information contained in this news release has also been reviewed and verified by L.J. Bardswich, P.Eng., General Manager of Golden Vertex Corp. and a Qualified Person ("QP") for the purpose of National Instrument 43-101 (Disclosure Standards for Mineral Projects).
Source: http://www.northernvertex.com/