Great Basin Gold Ltd., (TSX: GBG; NYSE Amex: GBG; JSE: GBG) announces that trial mining in the Blanket Zone above the Main Clementine vein #18 at its Hollister project in Nevada has encountered bonanza grades of gold and silver.
The Company cautions investors and readers that we are making this announcement out of an abundance of concern over interpretation of this information and, as the information may be known locally in the region of the mine site, the Company felt obligated to make it public.
Channel sampling carried out in conjunction with trial mining in the Blanket Zone has encountered the bonanza grades over a strike distance of 170 feet (57 meters).Channel samples taken every 10 feet (3 meters) gave values ranging from a low of 1.5 oz/ton(52.0g/t) Au and 3.2 oz/ton(111.9 g/t) Ag to a high of 2,560.4 oz/ton (88,845.9 g/t) Au and 1,829.8 oz/ton (63,494.1 g/t) Ag over channel widths from 0.3 to 2 feet wide. The current stope is continuously mineralized along its 180-foot (60-meter) length. Diluted over 3.5 feet (the width of the stope development), the average sample values were 66.4 oz/ton (2,404 g/t) Au and 78.5oz/ton (2,723.9 g/t) Ag. Muck piles have also been sampled; grabs are taken over the pile to collect as representative a sample as possible (between 10-15 lb. are collected every 10 feet). The fully diluted value of the muck samples taken from the stope to date averages 22.3 oz/t (773.8 g/t) Au and 23.4 oz/ton (811.9 g/t) Ag.
The Blanket style mineralization at Hollister is typified by very fine grained disseminated gold hosted by tuffaceous horizons in the Tertiary (10-15 million years old) volcanics that lie unconformably on the basement Ordovician (~430 million year old) metasediments. These zones of mineralization are thought to be "mineralization plumes" directly related to the activity of fluid which has focused in structures that control the underlying epithermal quartz - adularia veins, and propagated into the Tertiary volcanic pile.
Blanket mineralization was previously exploited by opencast methods during 1990-1992 by the Touchstone - Galactic Joint Venture. According to historic records, 115,000 ounces of gold were produced by a heap leach operation that treated low grade ore (~0.003 oz/ton or 1 g/t Au). Great Basin modeled all 46 drill intersections above the Tertiary unconformity, and +1 g/t grade shells generally locate above known mineralized quartz - adularia veins. In general, this style has been located in the first ~30 feet (10 meters) above the unconformity, and may have dimensions in excess of 150 feet (50 meters) long and 60 feet (20 meters) wide. Grades from these 46 drill intersections average 0.45 oz/ton Au (15.4 g/t) and 1.7 oz/ton Ag (59 g/t).
Extrapolation of stope 3000N 1E to surface (approximately 200 feet or 67 meters vertically above), places this zone 300 feet (100 meters) west of the historical Clementine mercury mine. It supports the near surface working metal zonation and gold deposition model for the Hollister mine, and indicates additional exploration potential.
Ferdi Dippenaar, President and CEO, commented: "In the past, we have identified the Blanket Zone as a target area worth exploring, and trial mining at the top of vein #18 has turned out to be a great way to test the prospective nature of this style of mineralization. Although we have encountered a limited amount of this high grade material through trial stoping, drilling is underway to determine the full extent of mineralization. More information will be made available as and when it becomes available. Based on our experience in the Main Clementine vein #18, we are evaluating the possibility of returning to previously stoped out areas above the Gwenivere high grade veins."
Phil Bentley, Pr.Sci.Nat. (SACNAS) Vice President for Geology and Exploration for the Company and a qualified person, and Johan Oelofse, PrEng, FSAIMM, Chief Operating Officer for the Company and a qualified person, have reviewed this news release on behalf of Great Basin.
Source: Great Basin Gold Ltd.