ATAC Resources Ltd. is pleased to announce very significant gold results from diamond drilling at its wholly owned Rau property in the Keno Hill District of central Yukon. The discovery lies on the northern edge of the prolific Tintina Gold Province, a belt of mostly intrusion-related gold deposits that stretches across Yukon and Alaska.
Encouraging surface results and visual evaluation of drill core have now been confirmed by assays from core samples that average 1.237 g/t (0.036 opt) gold across a thickness of 68.69 m (225.4 ft). Assays are pending for nine nearby drill holes that cut similar thicknesses of the same type of mineralization. Management is excited about the consistency of mineralization from hole to hole and believes that this is an important discovery with exceptional size potential.
Graham Downs, CEO, states that “ATAC has moved quickly to capitalize on this unique opportunity. The drill program has been extended to continue through fall and we expect to see more than 20 holes completed in this zone before the end of the exploration season. The extended diamond drill program will seek to establish the extent of the zone (which is open to expansion in all directions) and will search for especially high grade areas within it.”
In response to the discovery, ATAC has dramatically expanded its land position by staking an additional 1297 mineral claims in the favourable geological belt. The Rau property now totals 1393 claims covering an area 30 km long and up to 12.5 km wide. The claims extend easterly from the Wind River Trail, a route that has traditionally been used to transport heavy equipment into the district. An access road to the drill area from the closest point on the Yukon highway system would cross gentle terrain and have a total length of 57 km.
The gold mineralization is stratabound and is hosted in porous reefal limestone and dolomite of the Cambrian to Devonian age Bouvette Formation. The mineralized strata are on the outer fringe of a large and well zoned hydrothermal system developed above and around a Late Cretaceous granitic intrusion. The system is roughly centred on a small, poorly exposed intrusive stock that outcrops about 3 km east of the gold zone. Narrow, apparently coeval aplite and pegmatite dykes and sills are found over a much larger area. The intrusions are strongly fractionated, often containing various forms of tourmaline, unusual micas, beryl, garnet and wolframite. Skarns developed near the intrusive centre are irregularly mineralized with scheelite while more distal veins contain lead and zinc minerals.
The gold bearing strata range from about 50 to 90 m thick in drill holes. They are deformed by open, asymmetric folds with northwesterly striking subhorizontal axes. The folds exhibit northeasterly vergence related to two regional-scale southwesterly directed thrust faults that bound the favourable package of rocks. The host rocks are dolomitized and typically contain 5 to 20% sulphide minerals including (in approximate order of abundance) pyrite, arsenopyrite and pyrrhotite. Bismuthinite and scheelite are present in trace to minor amounts. Sulphide minerals occur as coarse disseminations and replacements. Total sulphide content is thus far consistent from hole to hole. The mineralized unit is overlain by a talc altered sequence with minor sulphides on fractures. This unit may have acted as an impermeable cap rock that helped to channel mineralization fluids laterally into the porous underlying dolomite host rocks.
Discovery of the gold mineralization resulted from follow up of a 99th percentile gold value reported by a reconnaissance-scale stream sediment survey. The zone itself was first identified by grid soil sampling, which outlined a 600 m long by 100 to 300 m wide area of largely coincident, very strongly anomalous gold and arsenic values. The geochemical anomaly is open to extension to the northwest. This area has now been grid sampled but results are not yet available. The zone is not conductive but it did show up as a second-order magnetic high on a helicopter-borne VTEM survey. Prospecting located limonite-rich float with occasional residual sulphides in the vicinity of the soil geochemical anomalies, but it has not found the zone in outcrop. In light of drill results, the discovery was very fortuitous because the area of mineralization is much larger than was suggested by surface work. A creek has eroded into the zone where an anticlinal fold brings it close to surface, otherwise the mineralization would have been completely buried. To the southeast and northwest, the fold axis projects under ridges so the mineralized beds are not exposed; to the northeast and southwest the host strata dip beneath cover rocks on either limb of the fold axis.
Eleven holes have so far tested the gold zone, and all but the first hole have cut the mineralized strata. Rau-08-01 was drilled near a ridge crest at the southeast end of the soil anomaly. It appears to have passed above the fold hinge, intersecting only weakly mineralized fractures in hanging wall stratigraphy. The other ten holes have been drilled on two lines: one paralleling the fold axis along the presumed length of the zone and the other aligned perpendicular to the fold axis across the presumed width of the zone. The holes that are located along the length of the fold axis have successfully traced the mineralized zone for a distance of 350 m. The holes drilled across the fold axis have defined an anticlinal axis and are beginning to define a synclinal axis. Unfolded, this section represents about 280 m of mineralized stratigraphy. All but one hole on the north limb of the fold axis had excellent recovery and cored solid, sulphide-bearing rock. The only hole on the south limb (Rau-08-03) intersected deeply weathered, oxidized rocks that yielded poor core recovery. Most material returned from this hole consisted of limonite boxwork or limonite mud. The gold-rich strata remain open to extension in all directions. Plan view maps, a drill cross-section, annotated photos of the drill area and pictures of the core are all available for viewing on the company’s website – www.atacresources.com.
The sample intervals in hole Rau-08-02, which combined to total 68.69 m, individually ranged from 1.00 to 2.23 m in length. The grade of the individual samples ranged from 0.135 to 7.62 g/t gold, with most samples between 0.300 and 1.5 g/t. The average grade of 1.237 g/t gold, which is reported for samples collected from Rau-08-02, was calculated in a weighted manner reflecting variations in sample lengths.
All analyses referred to in this news release were performed at ALS Chemex in North Vancouver, BC. The samples were collected and handled in ways that ensures security, including chain of custody procedures. Blank and standard samples were randomly included in every batch of 20 core samples. Gold analyses involved fire assay followed by inductively coupled plasma-atomic emission spectroscopy. Analyses for other elements on drill core were done by inductively coupled plasma combined with either mass spectroscopy or atomic emission spectroscopy.