Noranda’s Geco seeks prospecting rush

The Geco mine, a profitable zinc/copper producer year in and year out for the past 32 years, faces extinction. Within eight years, the orebody will have been exhausted. And this town, the lifeblood of which has been Geco’s mineral riches and the ripple effect of the nearby Hemlo goldfields, will suffer.

Noranda owns the Geco. From the recent surveys and after ground reconnaissance, diamond drill targets will be tested, probably some time next year.

“We have quite a few anomalies,” said Mine Manager Frank Grebenc. (Since the visit to the property by The Northern Miner, Grebenc has moved to Hemlo Gold Mine’s Golden Giant mine, about an hour’s drive from Manitouwadge.) He said diamond drilling should be under way by next year.

Chief Geologist Hugh Lockwood said any base metal find within a 40-mile radius of Geco would be of extreme interest. “We’re looking for good, high grade sources of ore to feed the mill.”

The airborne surveys tested the main structure that hosted the Willroy, Willecho, and Nama Creek mines, as well as Geco, which is the undisputed granddaddy up here. Lockwood said the surveys also took in heavily granitic areas and remnant greenstone and gneissic rock formations.

Mike Zurowski, vice-president of exploration for Hucamp Mines (COATS), which holds ground adjoining Geco, said that ground surveys were extensive in the late 1950s when Manitouwadge was bustling with exploration activity. Surface drilling was prevalent as well. But he didn’t dismiss the area’s potential despite earlier failed attempts at locating other orebodies.

“The overburden is fairly shallow and there are outcrops. You’re looking for vents that have been punched up through sedimentation,” Zurowski said.

Geologically, the Geco deposit is a volcanogenic massive sulphide deposit on the south limb of an easterly plunging folded sequence of metamorphosed Archean volcanics and sediments. On the north limb of the syncline, deep drilling to 4,000 ft turned up no economic mineralization.

Hopes are diminishing for any further finds accessible from underground workings. Noranda is driving an exploration drift on to the westerly Hucamp ground at the 3850 level underground but diamond drill results have not been encouraging from stations in the 2,000-ft-long drift. “We have cut intersections along the Geco mine horizon, but nothing economic,” Lockwood said.

Geco currently mills at a rate of 4,100 tons per day. As the depletion deadline nears, mill head grades will decline. To delay as long as possible the closure, Geco is gradually increasing daily tonnages to offset declining grades.

To promote exploration, Geco has asked the Ontario Geological Survey to re-map the area using results from its airborne surveys.

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