Exploration carried out by Erdene over the past four years has established Altan Nar as a significant new carbonate base metal gold system. Exploration work on the entire exploration 100% Erdene-owned license, specifically the 2013 through 2016 programs, including mapping, geochemical and geophysical survey programs, and a multi-stage scout and resource delineation drilling program, has greatly expanded the areas of known mineralization with 18 target areas now documented over a 5.6 kilometre long area.
Previous work has included extensive mapping, soil geochemical surveys, rock chip sampling and geophysical surveys and the work of several experts in epithermal deposits who focused on the style and paragenesis of mineralization, spectral analysis of alteration mineralogy, structural geology and drilling (122 diamond drill holes totaling 18,987 metres).
In Q4 2016, Erdene identified a previously untested high-grade core in the central portion of the Discovery Zone, one of the 18 targets. That discovery was further delineated in Q2/Q3 2017, with drill results including:
- TND-101: 15 metres of 52.3 g/t gold, 125 g/t silver, and 5.3% combined lead-zinc
- TND-104: 8 metres of 6.1 g/t gold, 92 g/t silver, and 1.45% combined lead-zinc
- TND-105: 14 metres of 7.9 g/t gold, 44 g/t silver, and 1.8% combined lead-zinc
- TND-110: 20 metres of 10.3 g/t gold, 37 g/t silver, and 1.7% combined lead-zinc
Erdene announced a maiden resource estimate for Altan Nar in March 2015 incorporating results from 71 diamond drill holes totalling 10,819 metres. Subsequently, between Q3-2015 and Q4- 2017, the Company completed an additional 51 diamond drill holes totaling 7,782 metres. The post-2015 drilling focused on expanding existing resource boundaries in the Discovery Zone (“DZ”) and Union North (“UN”) deposits, as well as expanding and exploring for additional mineralization within the remaining 16 target areas throughout the 5.6 kilometre trend, and resulted in the discovery of a high-grade central core in the DZ area while outlining additional resources in the peripheral targets. An updated Resource Estimate was announced on May 10, 2018 (click here) which reported a 208% increase in the Indicated Gold Equivalent (“AuEq”) resource and a 172% increase in the Inferred AuEq resource;
- Indicated Resource of 452,900 ounces (“oz”) AuEq averaging 2.8 g/t AuEq and Inferred Resource of 277,100 oz AuEq averaging 2.5 g/t AuEq, within a total resource of 5.0 million tonnes (“Mt”) Indicated and 3.4 Mt Inferred.
- Indicated Resource includes 317,700 oz gold (at 2.0 g/t gold), 31,600 tonnes (“t”) zinc, 29,000 t lead, and 2.35 million oz silver, while the Inferred Resource contains 185,700 oz gold (at 1.7 g/t gold), 23,700 t zinc, 22,300 t lead, and 865,900 oz silver.
- AuEq grade increased by 12% in the Indicated category, and 19% in the Inferred category.
- Gold grade increased by 18% in the Indicated category, and 13% in the Inferred category.
- Approximately 90% of the Mineral Resource is within 150 metres of surface with all zones open along strike and at depth.
Erdene has completed follow-up metallurgy (leach test recoveries of up to 96% over 48-hrs) and hosted several independent consultants to assist in on-going interpretation, including: Dr. Jeffrey Hedenquist, a leading expert on epithermal gold systems; Mr. Imants Kavalieris, a specialist in alteration studies of epithermal and porphyry systems; and Dr. Armelle Kloppenburg, an experienced structural geologist.
Altan Nar is considered to be a carbonate-base metal gold (“CBMG”) deposit, and is characterized by multiple, sub-parallel, moderately- to steeply-dipping, epithermal vein and breccia zones that in all cases remain open at depth and along strike. CBMG deposits are a sub-class of epithermal deposits that include the most prolific gold producers in the southwest Pacific Rim including well-known deposits such as Barrick Gold’s Porgera mine (Papua New Guinea), Rio Tinto’s formerly producing Kelian mine (Indonesia), and Continental Gold’s Buritica project (Columbia). CBMG deposits generally occur above porphyry intrusions in arc settings and typically contain gangue of a carbonate, base metal mineral assemblage and form as fracture/vein/breccias. Altan Nar has this typical gangue mineral assemblage. Mineralized zones in these deposits are commonly restricted to fault/fracture zones and also within phreatomagmatic breccia zones or pipes that may extend for more than 500 metres vertically as at the former-producing Kelian mine.
The Altan Nar license has a 1% net smelter returns royalty (“NSR Royalty”) in favour of Sandstorm Gold Ltd.