Work History
Staked as Greg cl (Y32767) in Jul/69 by Atlas Exploration Ltd for the Hess Project (Atlas, Quebec Cartier Mining Company, Phillip Brothers (Canada) Ltd) which carried out prospecting and geochemical sampling later in the year.
Restaked as Plata cl 1-280 (Y68588) and Inca cl 1-32 (Y68955) in August and Sep/72 following detailed prospecting by a joint venture between Dynasty Exploration Ltd (80%) and Atlas Exploration Ltd (20%), which carried out grid soil sampling, geological mapping, geophysical test surveying, hand trenching and drilled 6 holes (400.8 m) in 1972; construction of a winter road, a bush airstrip 10 km to the south, and 25 km of tote road on the claims plus grid soil sampling, detailed mapping and bulldozer trenching in 1973; staked Plata cl 281-288 (Y85186) in Sep/73; and further trenching in 1974. Atlas changed its name to Cima Resources Ltd in 1974 and Dynasty changed to Cyprus Anvil Mining Corporation in 1975.
A. Harman and Z. Lavoie, under an agreement with Cyprus Anvil, mined and shipped about 81.6 tonnes of hand cobbed ore to the Trail smelter in 1976. The Spis cl (YA42179) was tied on to the northeast in Aug/80 by the Argent Project (Rio Alto Exploration Ltd, Radex Resources Ltd, ABM Mining Group Inc, Ebony Resources Ltd and Welcome North Mines Ltd), which carried out geochemical soil sampling later in the year.
Control of the Plata property was acquired by Dome Petroleum Ltd in 1981. In 1983, the property was sold to Dawson Eldorado Gold Exploration Ltd and Silvercrest Resources Corporation, which mined 450 tonnes from open cuts and shipped it to a smelter. Most of the 1 360 tonnes mined and smelted in 1984 was mined from the Plata 2 Vein, while the remainder came from the nearby Inca vein system.
Between Nov/84 and Feb/85, Dawson Eldorado drove a 260 m crosscut about 100 m vertically below the 2 Vein open pit in a joint venture with AVF Group (Primary Exploration Ltd and Royal Bank Venture Capital Ltd) and drilled 13 holes in 1985. Dawson Eldorado changed its name to Dawson Eldorado Mines Ltd in 1985 and optioned the property to Pacific Trans-Ocean Resources Ltd, which drilled holes (670 m) on the #4 Vein and mined 74 tonnes from the Plata #6 Vein and 40 tonnes from the Plata #4 Vein in 1987. Dawson Eldorado transferred the Plata claims to Gold City Resources Inc in Aug/91. Gold City transferred the Plata claims to Avanti Minerals Ltd in Aug/93 and in Dec/94 Avanti Minerals Ltd transferred the Plata claims to Avanti Minerals (1994) Inc.
A private company, Big Blackfoot Mine Inc, subsequently acquired control of the claims and optioned a 70% interest in the property to Yukon Gold Corporation in Jul/96 and drilled 6 holes (750 m) later in the year. Big Blackfoot Resources Ltd acquired Big Blackfoot Mines in Oct/96. Yukon Gold changed its name to Alliance Pacific Gold Corporation in Jun/97, which drilled 16 percussion holes (200 m) over the following winter. The company later changed its name to International Alliance Resources, before dropping the option in Dec/2000.
Big Blackfoot then optioned the property to Copper Ridge Explorations Inc in May/2001 and after Copper Ridge dropped the option, to First Star Innovations Inc. in Apr/2003.
Strategic Metals acquired the property in 2007. Strategic Metals flew and airborne magnetic and VTEM survey over the entire property in 2007. Rockhaven Resources Ltd. bought the Plata and Inca properties from Strategic Metals in exchange for stock in Rockhaven's company in 2008. Rockhaven's 2008 exploration program included diamond drilling (4113 m in 51 holes), excavator trenching and a VTEM geophysical survey primarily targeting the Plata thrust fault. Drilling expanded the area of known mineralization within the Plata thrust fault 500 m down-dip and 850 m along strike. A new surface showing of gold and silver rich material was also discovered through trenching.
Rockhaven's 2009 program consisted of excavator trenching and diamond driling (346.6 m). The drilling tested an area between the P-3 and P-4 veins, located 300 m apart, which confirmed the continuity of mineralization between the two veins.
In March 2011, Silver Predator Corporation optioned the property from Rockhaven and drilled 2565.56 m in 17 holes. Seven holes were directed toward the P-6 Zone, five holes targeted the Aho Zone, four holes were directed toward the P-2 Zone, and one hole was collared at the P-12 Zone. Drilling at the P-6 Zone returned encouraging results, including 1655 g/t silver over 1.0 m, 846.5 g/t silver over 1.3 m and 699.0 g/t silver and 0.72 g/t Au over 1.53 m. Drill holes targeting the P-2 Zone yielded intercepts of up to 1060 g/t silver and 3.86% zinc over 0.87 m and 110 g/t silver and 39.77% zinc over 0.93 m. Silver Predator later dropped the option.
In October 2015, the Plata property was transferred back to Strategic Metals. In 2017, Strategic did some road upgrading at the site.
Capsule Geology
The more than 14 veins comprising the Plata occurrence occur over a 2 by 5 km area. Two types of veins are present, both hosted in fault or fracture zones cutting the structural fabric in Proterozoic and/or Lower Cambrian limestone, quartzite and shale and unconformably overlying Devonian shale and chert. The Plata 1,2,3,5 and 6 Veins, and many other minor occurrences, occupy NE or NW-striking fracture sets in the structural hanging wall of a major thrust fault. The mineralized veins consist of galena and sphalerite in a siderite gangue. Silver occurs in tetrahedrite-rich sections associated with galena. Silver to lead ratios are highly variable, ranging from 1:1 to 10:1 over short distances on a single vein.
Most of the exploration, development and production has been concentrated on a galena-rich section of the 2 Vein. This deposit occurs along the southwest-plunging contact between Late Proterozoic limestone and overlying Devonian shale. The exploration adit intersected the vein about 100 m below and some distance to the northeast of the mining bench. The adit and subsequent underground drilling intersected five weak vein zones mineralized with siderite and sphalerite.
The 4 Vein occupies a major gently southwest-dipping thrust fault that is associated with a 1 to 3 m wide quartz feldspar porphyry dyke of probable mid Cretaceous age. Mineralization consists of disseminated pyrite, arsenopyrite, tetrahedrite and other sulphosalts in a massive white quartz gangue. Lenses of massive pyrite-pyrrhotite-galena-sulphosalt are also present. Specimens of the latter material range up to 20.9 g/t Au and about 6800 g/t Ag.
The 1983 shipments, which were mined mainly from the 2 Vein and partly from material stockpiled in 1973 from 5 and 6 Veins, averaged 4 050 g/t Ag and 59.3% Pb. The 1984 shipments from the 2 Vein averaged 5656 g/t Ag and 70% Pb while the 1987 shipment graded about 6 900 g/t Ag. The 1976 shipment was mined from Veins 1, 22, 6 and reportedly averaged about 7 700 g/t Ag and 80% Pb. Metallurgical testing showed the flotation of the galena-rich mineralization in the 2 Vein would produce a 92% recovery but that the complex Ag-Au ore in the 4 Vein was not amenable to flotation.
Drilling in 1996 on the 4 Vein and its downdip extension, intersected quartz-sulphide mineralization in hole Plata-2 that assayed 17.14 g/t Au and 4.5 g/t Ag over 2.1 m. Reserves for the 4 Vein in Nov/96 were reported as 453 592 tonnes grading 3.77 g/t Au, 376.71 g/t Ag and 10% combinded Pb-Zn.
In 2009, one of two drill holes completed between the P3 and P4 veins returned an assay of 360.00 g/t Ag, 3.29 g/t Au, 1.98% Pb and 4.17% Zn over 1.64 m.
Various historical resource estimates are quoted in reports, probably from internal company reports, none of which are NI 43-101 compliant.
