Osisko to 'carpet bomb' Kirkland gold prospect after drilling 128m @ 2.3 g/t Au

Osisko Mining reports discovery of disseminated gold in the Kirkland camp in Ontario in a prospect it is to drill heavily.

SEATTLE, WA (MINEWEB) -

A major drill program is in the works by Osisko Mining following discovery of broad intercepts of disseminated gold in the Kirkland gold camp in a hitherto underappreciated type of mineralization in an otherwise heavily-explored area where there are numerous historic gold prospects.

"From my standpoint it feels like a Canadian Malartic déjà vu," said Robert Wares, Osisko's vice-president of exploration and the leading geologist behind the discovery of the company's Canadian Malartic gold deposit. Wares spoke with Mineweb on Friday afternoon about coming exploration that Osisko - now the subject of a ~C$3 billion hostile takeover bid by Goldcorp - has planned.

Wares described Osisko a 50,000-metre drill program with eight to ten drill rigs that are to grid drill what it now calls the Kirkland project, in Ontario, after it redrilled old ground with fresh eyes for disseminated gold. Through the recent program Osisko hit a pair of 100-plus-metre intercepts, fairly near surface, respectively grading about 0.99 g/t Au and 2.26 g/t Au, assuming a 0.35 g/t cut-off and starting 110- and 40-metres downhole. Intercepts in two other drillholes described by Osisko also hit gold mineralization.

The déjà vu - if far from being understood in terms of scale next to the 10-million-ounce Canadian Malartic gold mine - is this: that in drilling Kirkland, Osisko is on to previously under-appreciated - or totally un-cared for - disseminated gold mineralization in host rock that was nearly completely ignored by companies that explored the property in the past.

Logically in past exploration - during times of much lower gold prices - exploration efforts have focused on high-grade gold in Canadian gold camps known just for that. So in drilling and subsequent assaying in the lab this has meant host rock - outside the veins and veinlets that typically have hosted gold in Kirkland and other Archean gold camps in Canada - was largely ignored and untested. The geologist looking for obvious high-grade potential, thought, "Why bother?"

And rightly so. One-gram per tonne rock didn't hold much sway in the past.

Thus it comes as no surprise that the ground Osisko is taking a fresh look at - near favourable Kirkland camp structures that played a roll in high-grade gold mineralisation - is quite well covered by past drilling. Indeed, Wares confirmed to Mineweb the location of its latest drilling in reference to a recent map with a compilation of past exploration, produced in a 2011 report by Newstrike and Queenston (Osisko acquired the land through its acquisition of Queenston) and emailed to Osisko with a request for an interview.

OSISKO DRILLING

Maybe not the prettiest map, but its the best you'll get right now. Past drilling collars are shown on this map of the area where Osisko made its recent Kirkland discovery of disseminated gold (big arrow). Osisko is to focus its drill efforts on the area beneath, roughly speaking, the blue rectangle. Highway 66 to the north cuts the Commodore deposit. (Credit: Newstrike/Queenston, 2011; additions: Kip Keen)

Osisko's drilling is in the thick of it, as pointed out by the larger arrow on the map (above). Although the new drilling - to come roughly in the area beneath the rectangle of text - will cover well-drilled ground, as Wares noted, Osisko will test the full length of core for gold mineralization unlike its predecessors on the property.

An extensive area appears open to potential bulk mineralization, though only much more drilling can prove if gold in its disseminated form is pervasive. Osisko sees disseminated gold coming in altered zones of volcanic tuffs, or rock, made up of ejected ash and the like from an ancient volcano, that has subsequently been changed beyond recognition from its violent past. Importantly, this target rock type is described in disparate areas at the Kirkland project through former drilling campaigns, much of it within a kilometre radius or so of Osisko's drilling.

(And that said it seems there is potential to apply the model beyond.)

Such rock was described in the best known area of gold mineralization on the property a kilometre northwest of Osisko's drilling in the Commodore deposit. This is the only area where the rock outcrops, Wares says, in a road cut for Highway 66. According to historic estimates from the 1990s, Commodore holds about 670,000 tonnes @ 2.4 g/t in resources.

The target rock was also described in initial drilling during the 1940s on the property when trace gold was first noted in a zone about a half-kilometre to the east of Osisko's latest drill program. And, not surprisingly, the area that Osisko has drilled showed some potential in the past - though it was looked over. Inco, Wares said, drilled it in the 1960s and 1970s and it cut some lower grade gold over about 30 metres.

With a new model for gold mineralization at Kirkland, Osisko's drillhits appear to be the first indication of broadly mineralized gold zones in the 100-metre range, (though, it should be cautioned, deposit shape is poorly understood so far.) Now there is really little else to do but drill. And lots. As at Canadian Malartic, geophysics aren't helpful to Osisko in identifying disseminated gold targets at the Kirkland project - where there is also little outcropping rock - given low sulphides with about one-percent pyrite.

"We'll carpet bomb this with drilling," Wares said.