GOLD AND PRECIOUS METALS — Rubicon tests extension of Red Lake gold trend

A recent drill program in the Red Lake area of northwestern Ontario suggests the structure that plays host to the camp’s two biggest mines has potential to hold more mineralization along strike.

Rubicon Minerals (RMX-V) drilled 11 holes on its main Red Lake property, testing the upper 150 metres of a structural corridor it has dubbed Dorion-McCuaig. The corridor is the northwestern structural extension of the Mine Trend deformation zone that hosts both the Campbell mine of Placer Dome and the Dickenson (Red Lake) mine of Goldcorp. It extends into Red Lake near McKenzie Island.

The 11 holes, which combine for 2,458 metres, encountered mineralized intervals with gold grades higher than 0.5 gram per tonne. Trace-element analyses showed unusually high concentrations of arsenic, antimony, mercury and tungsten, all of which are known to be enriched in rocks around the producing gold deposits on the Mine Trend.

The drill program got its best results at the western end of the deformation zone, in holes drilled from collars on Dorion Island. Hole RL98-03 was drilled northward toward the middle of the deformation zone and cut a 21.2-metre interval of mineralized core grading 0.6 gram gold over its entire length, with a 1-metre length in the interval grading 3.5 grams.

A second hole, RL98-02, was collared about 200 metres east of RL98-03 and drilled northward, cutting 3.3 metres grading 1.8 grams gold.

Two holes, RL98-11 and RL98-12, were drilled to the east-northeast to intersect splay structures in the deformation zone. Hole 98-11 encountered 5.8 metres grading 3.2 grams gold and 98-12 intersected 2.3 metres grading 2 grams.

Hole RL98-08, collared on Dull Island near the eastern end of Rubicon’s property, was drilled southward into the main structure. It cut two zones of mineralization, one grading 3 grams gold over 0.4 metre and another grading 2.3 grams over 0.2 metre.

Three other holes drilled into the zone from small islands between Dorion and Dull Island also found the mineralized structures, encountering lower gold concentrations (between 0.5 and 2 grams).

Rubicon also drilled two holes on the adjacent McCuaig property, where Rubicon has the option to earn a 50% interest from Golden Tag Resources (GPG-V). These holes, with a total length of 575 metres, returned no significant gold values.

The company has identified three possible environments of gold mineralization in the Dorion-McCuaig corridor. Gold is found in siliceous breccias in southeasterly striking “horsetail” splays from the Coniagas fault, the central structure in the corridor. Iron formations north of the fault, which lie between two sequences of volcanic rocks, and quartz-carbonate veins in komatiites that form the footwall of the Coniagas fault, also carry mineralization.

A large part of the mineralization at Campbell occupies the contact between the two volcanic sequences, where shearing has provided plumbing for mineralizing fluids. Hydrothermal alteration is strongly developed in the rocks adjacent to the shears, especially in the ultramafic rocks of the komatiite sequence.

Erratic high-grade gold showings are common along the deformation structures in the Red Lake camp. These showings have frequently developed into more persistent mineralization at depths of roughly 250 to 300 metres. Rubicon’s conclusion is that the mineralized zones it encountered in this shallow drill program may serve as indicators of larger concentrations of gold at depth.

Rubicon is also exploring its Peterson project, 5 km east of the Red Lake mine, where two drill holes intersected multiple zones of mineralization with grades in the 1- to 3-gram range. Cores from these holes also show similar alteration and trace-metal content to the samples from the Dorion-McCuaig corridor.