Buoyed by encouraging results from recent drilling,
Company geologists believe the main bonanza stockwork zone is a breccia pipe, the apex of which is exposed as a topographic high known as Cerro Colorado III. It is one of three similar topographic highs in the region, all of which are found within a hydrothermal corridor about 1.3 km long.
The pipe is believed to have a diameter of about 150 metres and a true thickness of about 50 metres, and is open down-plunge to the east. Intrepid says the topography is conducive to a low stripping ratio, “thereby enhancing the economics of the open-pittable, high-grade zone.”
The company recently drilled eight reverse-circulation holes to test the silver bonanza stockwork exposed during the trenching program at Cerro Colorado III. Four of these holes targeted the main stockwork structure and confirmed a thick zone of continuous, high-grade silver values. The zone adjoins the past-producing San Casimiro silver-lead-zinc mine a mere 500 metres to the north.
Results from the newly dubbed Main zone include: 55 metres grading 305 grams silver per tonne, including 9 metres of 572 grams and 11 metres of 498 grams; 54.5 metres of 170 grams, including 31.5 metres of 268 grams and 30 grams of 116 grams; and 45.5 metres of 449 grams. Three of the four holes intersected mineralization at surface, while the fourth did not return any significant values.
Hole 8 targeted the silver-gold contact on the west side of the stockwork and intersected 7.5 metres of 95.5 grams silver. Holes 5, 6 and 7 targeted a silicified structure adjoining the stockwork to the south, but returned only anomalous values.
President Laurence Curtis said the company is enthusiastic about the results of the first-phase program. “The pipe-like configuration of the bonanza stockwork, together with its high grades and open-pittable potential, will enhance the probability for success of this project,” he stated.
The mineralized breccia is hosted within a package of volcanic and sedimentary rocks that have been intruded by an early-Tertiary granodiorite and dacite porphyry. The pipe has high-grade disseminated and stockwork silver-lead-zinc mineralization. Sulphides consist of pyrite, acanthite, galena and sphalerite, with minor chalcopyrite and chalcocite, occurring in both the pervasive silica-flooded matrix and quartz-barite veins.
The mineralogy is described as “simple”, and preliminary bottle-roll tests have shown more than 88% recovery of silver and gold for material crushed to 80% less than 150 microns.
Surface work at the property continues, and drill roads to San Casimiro, the second gold-silver target, have already been prepared. Previous channel sampling within the mine workings yielded 417 grams silver over 16 metres. Channel samples taken across the structure at the site of the proposed drill pad assayed 358 grams silver over 5 metres, while surface samples near the site assayed 246 grams silver.
In light of isolated samples returning between 3-10 grams gold, the San Casimiro target is believed to host a silver-lead-zinc-gold breccia similar to that at Cerro Colorado III, but with a higher gold content.
The current program will test the down-plunge extension of Cerro Colorado III, as well as the silver-gold zone at San Casimiro.
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