Vancouver — Reverse-circulation drilling by
The first eight holes were collared 250-500 metres apart, and four of these yielded encouraging intervals of quartz-alunite-enargite-pyrite-chalcocite. Such mineralization is typical of major “high-sulphidation” gold systems. The mineralization is also associated with a complex system of eruptive breccias and fault structures.
Highlights from the drilling are outlined below:
– The first hole was collared on the western margin of the Filo del Sol diatreme and intersected 4 metres grading 4.92 grams gold and 2 grams silver per tonne from a down-hole depth of 42 metres. Owing to poor drilling conditions, the second hole, collared 250 metres to the east, was abandoned at 168 metres. The final 16 metres ran 0.53% copper, 0.48 gram gold and 2 grams silver.
– Hole 3 was collared about 1 km northeast of hole 2; it cut 2 metres averaging 1.1 grams gold from 14 metres down-hole.
– The best result came in hole 4, which was collared 250 metres east of hole 2 along the eastern margin of the Filo del Sol diatreme. This hole cut 118 metres grading 0.51% copper, 81 grams silver and 0.38 gram gold per tonne, starting at a down-hole depth of 162 metres. This interval included a higher-grade section running 0.55% copper, 192 grams silver and 0.39 gram gold, starting 202 metres down-hole. The hole terminated in mineralization. The last 10 metres graded 0.92% copper, 5 grams silver and 0.67 grams gold.
– Hole 5, was collared about 400 metres south of hole 4 and returned an encouraging 168-metre section averaging 0.86% copper, 33 grams silver and 0.23 gram gold starting at 96 metres down-hole. This included a higher-grade interval averaging 2.20% copper, 4 grams silver and 0.25 gram gold over 32 metres, starting at a down-hole depth of 100 metres.
– Hole 6, collared 250 metres east of hole 4, hit 28 metres averaging 0.53% copper, 4 grams silver and 0.19 gram gold from 92 metres down-hole.
– Hole 7, collared 500 metres east of hole 5 intersected 2 metres grading 0.15% copper, 41 grams silver and 2 grams gold from 128 metres down-hole.
Hole 10 failed to return any significant mineralization.
Rio Tinto Mining & Exploration, a subsidiary of London-based
The major can earn a 51% interest by spending US$10 million on exploration over four years. It can then boost its position to 60% by spending an additional US$5 million.
Tenke, led by the Lundin team, was also responsible for the discovery of the Veladero gold camp, 75 km to the south, and the subsequent US$190-million takeover of Argentina Gold by
In 1999, Tenke put together a package of ground, dubbed the Vicuna project and situated between the Maricunga belt to the north and the El Indio belt to the south. The exploration concessions had been held by
The Filo del Sol target, which measures 1.6 km by 200-350 metres, was discovered last year. It was outlined by geophysics and is said to have geological and geophysical characteristics similar to those of the Veladero deposit. Filo del Sol is hosted in a breccia complex comprising leached opaline silica. Tenke collected 39 soil samples over the target, which carried an average of 0.16 gram gold.
Tenke subsequently added to its position by optioning the Lirio property, which is adjacent to Vicuna, in return for exploration expenditures of US$1.5 million over five years. The company also has the right of first refusal on several properties north of Vicuna, known collectively as Yamiri.
Vicuna hosts a large hydrothermal system with high-sulphidation epithermal alteration and mineralization, as well as porphyry copper and gold mineralization. In addition to the Filo del Sol prospect, Tenke outlined four drill targets spanning 12 km from north to south. These are outlined below:
– Flamenco anomaly — This target represents a breccia complex about 3 km south of the Filo del Sol diatreme. The breccia is intensely deformed by north-northeast-striking faults. Alteration is marked by opaline silica and minor vuggy silica. Lying on the international border, this southernmost target hosts a large gold-in-soil geochemical anomaly, and numerous chip samples returned anomalous gold values. Hole 8 was drilled into this target and cut 82 metres averaging 0.41% copper and 0.16 gram gold.
– North anomaly — This anomaly, situated 7 km north of Filo del Sol, measures 4 km long by 1.5-4 km wide. An alteration zone of steam-leached silica, it contains anomalous mercury and sulphur. Soil geochemical analysis has revealed locally anomalous gold, silver, lead and molybdenum. Rock samples have yielded up to 0.22 gram gold and 93 grams silver per tonne.
– Marancelas breccia — Situated 3 km north of the Filo del Sol diatreme, this anomaly represents a 2-sq.-km alteration zone with widespread silicification and breccias. Soil and chip sampling revealed anomalous gold on the eastern side of the target in an area of quartz-enargite veining.
– Co. Vicuna — This prospect, 1 km south of Filo del Sol, represents a silicified porphyry with multi-stage vuggy silica covering 1.6 sq. km. Recent trenching returned 24 metres grading 1.24 grams gold, 6 metres of 3.04 grams, and 10 metres of 0.93 gram. Cyprus Amax previously tested the porphyry for copper with 16 drill holes. One hole intersected 20 metres grading 1.18 grams gold near the edge of a soil anomaly, starting at a depth of 4 metres. Hole 9 was collared on this prospect and hit 0.19% copper, 1.5 grams gold and 4 grams silver over 4 metres from surface.
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