Red Lake, Ont. — The Red Lake gold camp of northwestern Ontario had, over the years, come to look fairly simple: two big mines, one very big orebody, and very little going on outside the fences at Campbell and Dickenson.
That picture was always superficial and inadequate, but recent years have demolished it. Red Lake — thanks to a major discovery by
One of the best examples of the way the “other” Red Lake mines dropped off the radar screen is the camp’s third-largest producer — the Madsen mine, about 8 km southwest of the town of Red Lake. Madsen still had plenty of ore in the ground when it shut up shop in 1976, just before gold prices jumped; but the mine never came back into production, even during the flow-through years in the late 1980s.
Now a joint venture between Saskatoon-based gold producer
Madsen itself produced 2.4 million oz. gold between 1938 and 1976. After production ended, it passed through the hands of several owners, ending up with Red Lake Buffalo Resources in 1988. Red Lake Buffalo changed its name to Madsen Gold in 1991.
Madsen Gold pumped out the workings and started an underground exploration program, which ran through the mid-90s. Claude came to the property in 1998, at the nadir of the junior mining market, taking over Madsen Gold in a paper offer of one Claude share for every 3.5 Madsen shares.
Madsen had assembled a land package in the immediate area of the Madsen Red Lake mine, including four other storied Red Lake names: Starratt-Olsen, Aiken-Russet, Redaurum, and Buffalo Red Lake. Even though the Madsen mine, formerly a 2.4-million-oz. producer, was the focus of Madsen Gold’s efforts and of Claude’s interest, the surrounding properties covered a full section of Red Lake volcanic stratigraphy, and were cut by the northeast-striking Flat Lake-Howey Bay deformation zone — they had significant exploration potential.
That potential was recognized as early as 1999, when consultants for Claude noted a classic feature of Red Lake gold mineralization: deformed contacts between komatiites and basalts of the Balmer Assemblage. But gold prices were low, and Claude had plenty to do at its Seabee mine in Saskatchewan and at the Madsen workings.
But others noticed too, and eventually Placer Dome arrived with an attractive offer for an option deal. For $8.2 million over three years and the commitment to deliver a positive feasibility study after five years, the major would earn a 55% interest in the whole land package.
Even with an obligation to spend $1.2 million in the first year of the option, Placer wasn’t fast out of the blocks; the deadlines under the option agreement were pushed a year onward.
Northern targets
Still, early results from Placer’s airborne geophysics and surface work, which included both conventional and mobile-metal-ion geochemistry on soils, pointed Placer to targets near the northern end of Russet Lake, where the Balmer basalts were sandwiched between komatiite and a talc-carbonate schist. Drilled in 2002, they proved to host quartz-carbonate-tourmaline vein systems with pyrite, pyrrhotite and sometimes visible gold. “All the elements that you see at Campbell and Red Lake are here,” says Philip Olsen, Claude’s vice-president of exploration.
The whole Russet North alteration zone was about 300 metres wide and 900 metres long; grades mostly ran in the 3-gram range over intervals wider than a metre but touched 48.3 grams over a 0.2-metre width in one hole. Placer called the showing “Treasure Box.”
From the start, Placer had made it a practice to drill wide stepout holes at Russet North, setting up new holes 100 metres apart. The company’s thinking was that the Russet North program was an exploration exercise, not an attempt to drill off a resource, and that there was more value in getting an accurate handle on the stratigraphy and structure than there was in blocking out a mineralized zone that might or might not be worth further work.
The result is that a picture is emerging of vein systems largely controlled by a southeast-striking axial-planar cleavage, restricted to the less-ductile basalts. “Almost all the veining seems to occur in the basaltic formations,” says Placer’s Dean Crick, one of the geologists on the project. The cleavage fabric belongs to a second phase of deformation, which refolds around an axis roughly perpendicular to an earlier northeast-striking fold plane.
The drilling pattern adopted in 2003 reflected that knowledge, with some holes testing southeast-striking structures and others poking into an assumed northeast-striking structure oblique to the older fold plane.
Significant grades
Five holes in the 2003 campaign intersected significant gold grades, mostly in vein-type mineralization in the basalts. The veins were typically a metre or better in core length, and grades ran from a gram or so up to 21.1 grams gold per tonne. Four of the five holes showed visible gold. “If we can establish continuity on it then we’ll go to a tighter [hole] spacing and try and get a resource on it,” says Crick.
While concentrating on Russet North, Placer has also done early-stage work on the Starratt-Olsen property, about 2 km southwest of the Madsen mine. Starratt-Olsen is itself a 160,000-oz. producer from the 1940s and 1950s.
Mineralization at Starratt is mainly in sulphide zones, rather than quartz veins, in two previously known gold zones, Devilliers and Creek. A new zone of sheared and altered basalt — traditionally called “tuff” in the area but now thought to be a highly deformed flow rock — was found in Placer’s first pass of drilling, and dubbed the Footwall Tuff.
A couple of zones of quartz veining, with visible gold, were cut in the Devilliers zone, but the bulk of the gold was in sulphide replacements. Grades in the replacement bodies ranged from 1 to 5 grams per tonne over intervals of a fraction of a metre to 8.7 metres. The vein zones in the Devilliers zone were higher-grade, running 3.3 grams per tonne over 2.6 metres and 8.6 grams per tonne over 1.2 metres.
Placer has yet to do any drilling on the Madsen mine site in its joint-venture program, preferring to wait for the results of a three-dimensional compilation of all the mine site data, which were still in the works at the time of The Northern Miner’s visit. The workings at Madsen remain flooded, and Placer still has enough to occupy itself elsewhere on the joint-venture ground.
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