Orsu Metals Corporation (TSX-V: OSU) (“Orsu” or the “Company”) is pleased to announce positive cyanidation test results for oxide samples from Adit 5 and Kozie prospects at the Sergeevskoe Gold Project in Russia.
- At Adit 5, sampleTR5-17-1, grading 1.75 g/t Au, showed an 85.17% to 95.30% recovery of gold.
- At Kozie, sample TR2-17-2, grading 3.02 g/t Au, demonstrated gold recoveries of 91.72 % to 92.32%.
Dr. Alexander Yakubchuk, Director of Exploration of Orsu commented: “Our cyanidation tests for samples with oxide mineralization collected from Adit 5 and Kozie prospects achieved excellent recoveries of gold varying from 85% to 95%, depending on rock fractions, and amenability of oxide to heap leaching. Orsu is designing a 2018 exploration programme aiming to estimate mineral resources in oxide and sulfide material.”
The license of the Sergeevskoe Gold Project occurs immediately east from the Alexandrovskoe open pit and gold plant owned by Zapadnaya Gold Mining Ltd and to the west from the Klyuchevskoe gold license owned by Sun Gold Mining (Figure 1). The Klyuchevskoe (Klyuchi) gold deposit represents a +6 Moz gold endowment (see Orsu press-release dated September 21, 2016). Orsu owns a 90% interest in the Sergeevskoe Gold Project (see press release December 1, 2017).
As part of its 2017 exploration works, Orsu collected two samples from oxide material at Adit 5 and Kozie prospects for cyanidation tests. The samples consisted of rock fragments, 50 mm in size and smaller. The tests included studies of physical properties as well as bottle roll and percolation column cyanidation. The study was conducted at the SGS Vostok Limited (“SGS”) laboratory in Chita, Russia, which is independent from Orsu. SGS subcontracted a mineralogical study to the Institute of Mineralogy, Uralian Branch, Russian Academy of Sciences in Miass, Russia, which is also independent from Orsu.
Figure 1. An outline of the 7.6 sq km Sergeevskoe license area with location of principal gold prospects and two adjacent open pits.
Sample TR5-17-1 (94.74 kg) was collected from Trench S23TR17-5 (Fig. 1; see press release November 13, 2017) at the Adit 5 prospect. Mineralogical analysis identified that rocks consist of quartz, tourmaline and potassic feldspars. The rock is strongly oxidized, with abundant kaolinite and goethite. There is free gold up to 0.1 millimetre (“mm”) in size. The relic sulfides are mostly pyrite and subordinate arsenopyrite. SGS assayed 1.75 g/t Au and 1.32 g/t Ag in sample TR5-17-1, with 2.8% Stotal, 0.1% Ssulfidic, 0.15% Ctotal, and <0.05% Corganic. The oxidation state of sample TR5-17-1 is 99%.
Sample TR2-17-2 (80.52 kg) was collected from Trench SKZTR17-2 (see press release November 9, 2017) at the Kozie prospect. Mineralogical analysis identified quartz, tourmaline and potassic feldspar. Due to oxidation, the sample comprises 10.6% of kaolinite and 1.6% of goethite. The sulfides are mostly pyrite, oxidized into goethite, and rare arsenopyrite. Sample TR2-17-2 also contains free gold up to 0.1 mm in size. SGS assayed 3.02 g/t Au and 1.72 g/t Ag in this sample, with 1.55% Stotal, 0.15% Ssulfidic, 0.12% Ctotal, <0.05% Corganic. The oxidation state of sample TR2-17-2 is 90%.
Mineralization in samples TR5-17-1 and TR2-17-2 has low concentration of base metals (zinc, lead, copper, nickel) totalling 0.11% and 0.063%, respectively. They reveal low concentrations of arsenic and antimony.
In sample TR5-17-1, SGS measured a specific gravity of 2.58 t/m3 in all analyzed rock fractions, and density of stacked heaps is variable from 1.50 to 1.85 t/cubic meter for fractions -20 mm, -10 mm to -5 mm. The porosity varies from 41.8% in fraction -20 mm to 28.29% in fraction -5 mm.
In sample TR2-17-2, SGS measured a specific gravity of 2.75 t/m3 in all analyzed rock fractions, and density of stacked heaps is variable from 1.56 to 1.46 t/m3 for fractions -20 mm, -10 mm to -5 mm. The porosity varies from 43.3% in fraction -20 mm to 46.9% in fraction -5 mm.
Bottle roll tests
Bottle roll cyanidation tests were conducted over 48 hours for variable rock fractions . In sample TR5-17-1, the recovery into solution was:
- 73.70% for gold and 37.77% for silver from rock fraction -20 mm;
- 70.27% for gold and 54.09% for silver from rock fraction -10 mm;
- 86.59% for gold and 55.09% for silver from rock fraction -5 mm;
- 87.84% for gold and 67.33% for silver from rock fraction -1.75 mm;
- 93.13% for gold and 81.19% for silver from rock fraction -0.075 mm.
In sample TR2-17-2, the recovery into solution was:
- 83.94% for gold and 45.37% for silver from rock fraction -20 mm;
- 85.38% for gold and 68.19% for silver from rock fraction -10 mm;
- 85.23% for gold and 60.68% for silver from rock fraction -5 mm;
- 85.82% for gold and 63.22% for silver from rock fraction -1.75 mm;
- 89.73% for gold and 67.94% for silver from rock fraction -0.075 mm.
SGS concluded that gold in the analysed samples is mostly in free form, with very good recoveries amenable to heap leaching. Most gold is recoverable into solution during a period of 8 hours.
Percolation column tests
The cyanidation tests in percolation columns were performed for rock fractions -20 mm, -10 mm and -5 mm. The internal diameter of the percolation columns was 0.1 m for each fraction. The columns were filled up to 0.9-1.6 m. The columns were equipped with the sorption device for continuous sorption of gold onto China-made carbon ХНСР 20.
For sample TR5-17-1, the recovery of metals onto activated carbon during a period of 36 days was:
- 85.17% for gold and 73.08% for silver from rock fraction -20 mm;
- 93.91% for gold and 73.84% for silver from rock fraction -10 mm;
- 95.30% for gold and 77.59% for silver from rock fraction -5 mm.
For sample TR-2-17-2, the recovery of metals onto activated carbon during a period of 36 days was:
- 91.72% for gold and 62.95% for silver from rock fraction -20 mm;
- 92.32% for gold and 69.09% for silver from rock fraction -10 mm;
- 92.23% for gold and 69.31% for silver from rock fraction -5 mm.
Gold and silver are irregularly distributed in rock fractions. In sample TR5-17-1, most gold occurs in fraction -1.7+0.075 mm. In sample TR2-17-2, most gold was recovered from fraction -19.5+9.5 mm. Most gold was recovered from fine fractions, with sharp increase in recoveries from fraction -0.075 mm. This indicates that most gold is free and is in fine fractions.
Phase analysis showed that in sample TR5-17-1 there is 95.31% of gold that can be solved into cyanide. In sample TR2-17-2, there is 92.06% of gold that can be solved into cyanide.
This release and the technical data reported have been reviewed and approved by Alexander Yakubchuk, Director of Exploration of the Company, also a Qualified Person as defined in NI 43-101.
Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.
This news release contains forward-looking statements that are based on the Company’s current expectations and estimates. Forward-looking statements are frequently characterized by words such as “plan”, “expect”, “project”, “intend”, “believe”, “anticipate”, “estimate”, “suggest”, “indicate” and other similar words or statements that certain events or conditions “may” or “will” occur. Such forward-looking statements involve known and unknown risks, uncertainties and other factors that could cause actual events or results to differ materially from estimated or anticipated events or results implied or expressed in such forward-looking statements. There may be other factors that cause actions, events or results not to be as anticipated, estimated or intended. Any forward-looking statement speaks only as of the date on which it is made and, except as may be required by applicable securities laws, the Company disclaims any intent or obligation to update any forward-looking statement, whether as a result of new information, future events or results or otherwise. Forward-looking statements are not guarantees of future performance and accordingly undue reliance should not be put on such statements due to the inherent uncertainty therein.
For further information, please contact:
Alexander Yakubchuk, Director of Exploration, Orsu Metals Corporation
Doris Meyer, Corporate Secretary, Orsu Metals Corporation
Tel: +1-604-536-2711 ext 6