DRILLS 10.4 METRES GRADING 44.0% ZINC IN NEW DISCOVERY OF EXCEPTIONAL ZINC GRADE AT AYAWILCA
Tinka Resources Ltd. (TK.V) has released assay results for seven recent holes from its continuing resource stepout drill program at the company's 100-per-cent-owned Ayawilca project, central Peru. Six holes are reported from the West Ayawilca area (holes A18-117, 120 to 122, 126 and 129) and one from the Central area (A18-127).
Hole A18-129 has intersected exceptional grades of zinc sulphide mineralization at West Ayawilca in a new setting for mineralization at Ayawilca. A mineralized interval of 10.4 metres grading 44.0 per cent zinc occurs within a zone consisting of more than 90 per cent zinc sulphides (sphalerite). This is the highest-grade zinc intersection ever encountered at Ayawilca over a significant interval. The high-grade mineralization occurs immediately beneath phyllite (metamorphic rock) within a repetition of the Pucara limestone formation which is favourable for mineralization and typically found above the phyllite. The mineralized interval is interpreted to be flat dipping and close to true thickness.
This is the first time that Tinka has tested the proposition that there may be a repetition of the mineralized Pucara limestone under the phyllite encountered at the base of most other holes at Ayawilca. It is notable that such an outstanding zinc intercept has been drilled in the first repetition of the Pucara limestone encountered thus far. Additional drill holes are planned to test for the continuation of the high-grade mineralization in this repeated limestone.
The new discovery opens up significant areas of untested potential, both beneath and adjacent to the existing mineral resource. Most of the previous drill holes at Ayawilca were stopped a few metres into the phyllite, which had been considered to be basement. A new interpretation of the geology at West Ayawilca indicated that the favourable limestone unit could be repeated under low-angle thrust faults, a concept that is now corroborated.
Three drill rigs continue to operate at the project 24/7 in the resource expansion program. Two rigs are drilling deep holes at West Ayawilca, while the third rig is at South Ayawilca testing for repetitions of the mineralization beneath the South Ayawilca resource.
Key highlights -- West Ayawilca area
- 11.9 metres at 39.6 per cent zinc, 0.8 per cent lead, 45 grams per tonne silver and 761 g/t indium from 339.4 m depth;
- Including 10.4 m at 44.0 per cent zinc, 0.4 per cent lead, 43 g/t silver and 869 g/t indium from 340.6 m depth.
Shallower intercepts in A18-129 include:
- 21.2 m at 9.0 per cent zinc, 0.1 per cent lead, 13 g/t silver and 53 g/t indium from 260.0 m depth;
- Including 4.2 m at 19.2 per cent zinc, 0.1 per cent lead, 17 g/t silver and 186 g/t indium from 277.0 m depth;
- 6.5 m at 11.0 per cent zinc, 0.1 per cent lead, eight g/t silver and 52 g/t indium from 290.5 m depth.
Other significant recent drill intercepts follow.
- 7.8 m at 8.1 per cent zinc, 5.1 per cent lead and 183 g/t silver from 94.0 m depth.
- 2.4 m at 14.9 per cent zinc, 0.3 per cent lead, 25 g/t silver and 163 g/t indium from 351.3 m depth.
- 1.0 m at 23.7 per cent zinc, 24 g/t silver and 30 g/t indium from 101.1 m depth;
- 1.7 m at 18.9 per cent zinc and 28 g/t silver from 111.5 m depth*;
- 8.7 m at 3.9 per cent zinc, 1.4 per cent lead and 117 g/t silver from 235.7 m depth.
Note: True thicknesses of the zinc intersections are estimated to be at least 85 per cent of the downhole thicknesses, except for vein intercepts where true thicknesses are unknown.
Dr. Graham Carman, Tinka's president and chief executive officer, stated: "The exceptional zinc grade in hole A18-129 is very exciting as it confirms Ayawilca mineralization can be very high grade, while a repetition of the favourable Pucara limestone opens up a new exploration target at depth and also down-plunge of the new intercept. Previously, it was thought that the phyllite metamorphic rock represents a floor to the zinc mineralization. Past drill holes were typically stopped a few metres into the phyllite, and some holes at Ayawilca may have been stopped prematurely.
"The objectives of the drill program are to find additional high-grade zinc resources, as well as to improve the geological understanding of the Ayawilca deposit, which is evolving as more holes are drilled. The three-rig drill program is now focused on testing extensions of the zinc resources at West and South Ayawilca, including deeper repetitions of the limestone-hosted replacement mineralization, as well as possible connections of these areas with Central Ayawilca.
"The three rigs on site are expected to be operating until at least mid-August, 2018, at which time the number of rigs will be reviewed subject to results. Drilling at the zone 3 area, which has been one of our main target areas, will resume later in the year. A preliminary economic assessment is planned for the fourth quarter of 2018."
West Ayawilca geology -- a revised interpretation
The main geological rock units observed at Ayawilca are an upper sandstone (Goyllar group), a limestone (Pucara formation) which hosts most of the zinc mineralization as sulphide replacement of the limestone, and a lower phyllite metamorphic rock (Excelsior group). The observation by Tinka geologists of mineralized limestone underneath the phyllite in hole A18-129 is groundbreaking, as it opens up potential for additional zinc resources beneath and adjacent to the existing resources. Of particular importance is that the repeated section of Pucara limestone in A18-129 hosts much higher-grade mineralization than average, and the predominant zinc species is the relatively low iron ruby sphalerite.
Hole A18-129 intersected 70 metres of Pucara limestone, 10 metres of phyllite and then another 70 metres of limestone before cutting phyllite once again. Tinka geologists believe that the repetition in the limestone is as a result of a low-angle reverse fault which lies at the base of the upper phyllite, forming a thrust slice in the geology at West Ayawilca. Other thrust slices may also occur deeper in the sequence. The faulting is believed to have occurred prior to the zinc mineralization, but the low-angle faults acted as conduits for the mineralization. Zinc mineralization is hosted predominantly in the hangingwall position of the faults. The thrust faulting postdated the folding of the limestone-sandstone sequence which formed the anticline fold at West Ayawilca.
RECENT SIGNIFICANT DRILL INTERCEPTS AT AYAWILCA Drill hole From (m) To (m) Interval (m) Zn (%) Pb (%) Ag (g/t) Indium (g/t) A18-117 94.00 101.80 7.80 8.1 5.1 183 0 including 96.20 101.80 5.60 10.4 4.4 176 0 including 96.20 97.20 1.0 19.9 11.4 389 0 A18-120 293.05 301.80 8.75 3.6 0.1 5 3 and 349.40 353.70 4.30 5.1 0.1 81 274 A18-121 196.00 200.00 4.00 3.1 0.0 4 0 and 274.10 284.10 10.00 4.0 0.0 4 18 A18-122 351.30 353.70 2.40 14.9 0.3 25 163 A18-123 Results awaited A18-124 Results awaited A18-125 Results awaited A18-126 101.10 102.10 1.00 23.7 0.0 24 30 and 111.50 113.20 1.70 18.9 0.1 28 7 and 235.70 244.40 8.70 3.9 1.4 117 0 A18-127 299.40 314.00 14.60 3.9 0.0 3 84 A18-128 Results awaited A18-129 197.60 218.00 20.40 4.2 0.1 7 1 and 260.00 281.20 21.20 9.0 0.1 13 53 including 277.00 281.20 4.20 19.2 0.1 17 186 and 290.50 297.00 6.50 11.0 0.1 8 52 and 339.40 351.30 11.90 39.6 0.8 45 761 including 340.60 351.00 10.40 44.0 0.4 43 869 True thicknesses of the zinc intersections are estimated to be at least 85 per cent of the downhole thicknesses.
Qualified person -- mineral resources
The mineral resources disclosed in this press release have been estimated by David Ross, PGeo, an employee of Roscoe Postle Associates Inc., who is independent of Tinka. By virtue of his education and relevant experience, Mr. Ross is a qualified person for the purpose of National Instrument 43-101. The mineral resources have been classified in accordance with Canadian Institute of Mining, Metallurgy and Petroleum definition standards for mineral resources and mineral reserves (May, 2014). An independent National Instrument 43-101 technical report on the mineral resource estimate for the Ayawilca property, department of Pasco, Peru, has been filed under the company's profile on SEDAR and is available on the company's website.
The qualified person, Dr. Graham Carman, Tinka's president and CEO, a fellow of the Australasian Institute of Mining and Metallurgy, has reviewed and verified the technical contents of this release.
Notes on sampling and assaying
Drill holes are diamond HQ or NQ size core holes with recoveries generally above 80 per cent and often close to 100 per cent. The drill core is marked up, logged and photographed on site. The cores are cut in half at the company's core storage facility, with half-cores stored as a future reference. Half-core is bagged on average over one- to two-metre composite intervals and sent to SGS laboratories in Lima for assay in batches. Standards and blanks are inserted into each batch prior to departure from Tinka's core storage facilities. At the laboratory samples are dried, crushed to 100 per cent passing two millimetres then 500 grams are pulverized for multielement analysis by ICP using multiacid digestion. Samples assaying over 1 per cent zinc, lead, or copper and over 100 g/t silver are reassayed using precise ore-grade AAS techniques. Samples assaying over 200 parts per million tin are reassayed by fusion methods with an AAS finish (method AAS90B).
About Tinka Resources Ltd.
Tinka is an exploration and development company with its flagship property being the 100-per-cent-owned Ayawilca carbonate replacement deposit (CRD) in the zinc-lead-silver belt of central Peru, 200 kilometres northeast of Lima. The Ayawilca zinc zone inferred mineral resource estimate now consists of 42.7 million tonnes at 6.0 per cent zinc, 0.2 per cent lead, 17 g/t silver and 79 g/t indium, and a tin zone inferred mineral resource of 10.5 million tonnes at 0.63 per cent tin, 0.23 per cent copper and 12 g/t silver (Nov. 8, 2017, release).