O'Brien 637 ha
Cadillac, PQ Canada
Development - Preliminary Economic Assessment published in December 2015
5 potential plants for custom milling within 75km of the project*
*See metallurgical testing section below
The O’Brien project is located in the Abitibi region in northwestern Québec, on provincial highway 117, about halfway between the towns of Rouyn-Noranda and Val-d’Or. This project also contains the contiguous Kewagama property of Radisson located immediately to the east. Gravel roads provide easy access to the properties.
The O’Brien project is located in the central part of Cadillac Township, Abitibi, in the heart of one of the most productive gold mining camps in Canada, the Cadillac Mining Camp, which boasts over 45 million ounces of gold (produced and in reserves and resources) and 3 mines presently in commercial production.
O'BRIEN project - sensitivity at other cut-off scenarios (April 2015)
· The Independent and Qualified Persons for the Mineral Resource Estimate, as defined by NI 43-101, are Pierre-Luc Richard, P.Geo., M.Sc. and Alain Carrier, P.Geo., M.Sc., of InnovExplo Inc., and the effective date of the estimate is April 10, 2015.
· Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability.
· The resource model includes the previously named 36E and Kewagama zones. The historical O’Brien mine area is not included in this resource as it is not compiled nor validated at the time this estimate is being published. The model includes 56 gold-bearing zones; not all of which include resource at the official cut-off grade. A dilution envelope was also modelled, but no resource at the official cut-off grade is being reported for said envelope.
· Results are presented in situ and undiluted.
· Sensitivity were compiled at 2.0, 2.5, 3.0, 3.5, 4.0 and 5.0 g/t Au cut-off grades. The official resource is reported at 3.5 g/t Au cut-off grade.
· Cut-off grades must be re-evaluated in light of prevailing market conditions (gold price, exchange rate and mining cost).
· A fixed density of 2.67g/cm3 was used for all zones.
· A minimum true thickness of 1.5 m was applied, using the grade of the adjacent material when assayed, or a value of zero when not assayed.
· High grade capping (Au) was done on raw assay data and established on a sector basis (Western zones: 65 g/t, Eastern zones: 30 g/t, Western dilution zone: 3.5 g/t Eastern dilution zone: 4.0 g/t).
· Compositing was done on drill hole intercepts falling within the mineralized zones (composite = 0.80 m).
· Resources were evaluated from drill hole using a 2-pass inverse squared distance (ID2) interpolation method in a block model (block size = 3 m x 3 m x 3 m).
· The inferred category is only defined within the areas where blocks were interpolated during pass 1 or pass 2. The indicated category is only defined in areas where the maximum distance to closest drill hole composite is less than 20m for blocks interpolated in pass 1. Reclassification was conducted locally in order to respect CIM guidelines.
· Ounce (troy) = metric tonnes x grade / 31.10348. Calculations used metric units (metres, tonnes and g/t).
· The number of metric tonnes was rounded to the nearest hundred. Any discrepancies in the totals are due to rounding effects; rounding followed the recommendations in NI 43-101.
· InnovExplo is not aware of any known environmental, permitting, legal, title-related, taxation, socio-political, marketing or other relevant issue that could materially affect the Mineral Resource Estimate.
Historical inferred mineral resources (Charlton, 1995)
These “resources” are historical in nature and should not be relied upon. It is unlikely they conform to current NI 43-101 criteria or to CIM Standards and Definitions, and they have not been verified to determine their relevance or reliability. They are included in this section for illustrative purposes only and should not be disclosed out of context.
|Old O'Brien mine
LONGITUDINAL SECTION O'BRIEN PROJECT
metallurgical testing 36e area - 2014
11.13 g/t Au is the average grade obtained from the sample used for testing
Average recovery of 59.2% of the gold contained in the ore by gravity concentration calculated from the twelve (12) gravity concentration tests
Total recovery of 93–94% achieved by combining flotation or cyanidation with gravity concentration
The material used for the metallurgical testing was pulp from 36E area drill core. It consisted of composite core lengths from the main structures of 36E area (structures No. 1–6 and 8). The sample totalled 61 kilograms and had an average grade of 7.26 g/mt (0.212 oz/st) Au. Therefore, the grade of the material selected for metallurgical testing was very similar to the grade of the resource categories.
However, the average grade of gold recovered from the material tested was 11.13 g/t Au, with variations ranging from 7.47 to 14.59 g/t, which is nearly 56% higher than the grade of the sample prepared for these tests. Given the large amount of free gold in the sample used, the nugget effect may be responsible for this significant difference.
A first series of tests studied metallurgical recoveries that could be achieved with gravity separation. These tests produced a concentrate grading from 18,158 to 20,968 g/t Au, with recoveries in the order of 50–60% of the gold from the ore. The degree of grinding ranged from 58 to 80% minus 200 mesh; recovery improved as the grind became finer.
Subsequently, two processing circuits were considered. First, gravity concentration (Knelson concentrator and Mozley table) followed by flotation of the pulp of this concentrate in open and closed circuits. Gravity concentration produced a concentrate grading from 10,263 to 62,143 g/t Au, recovering from 54–67% of the gold from the ore. Flotation produced a concentrate grading 91 to 120 g/t Au. For most of these tests, a total recovery (gravity concentration and flotation) in the order of 93% to 94% was achieved. Some concentrates were analyzed for arsenic, producing results of about 12% As.
The second circuit consisted of gravity concentration (Knelson concentrator and Mozley table) followed by cyanidation of the pulp of this concentrate. Gravity concentration produced a concentrate grading from 25,598 to 30,508 g/t Au, recovering from 58–60% of the gold from the ore. A total recovery (gravity concentration and cyanidation) ranging from 90% to 93% was thus obtained.
For most tests, the degree of grinding used was 65–66% minus 200 mesh, a grind that is considered fine enough for this type of ore. In addition, reagent consumption, for both flotation and cyanidation, was similar to industry standards.