Brunswick increases reserves at Halfmile Lake deposit

On the eve of the 40th anniversary of the Bathurst, N.B., base metal discovery, Brunswick Mining & Smelting (TSE) has announced a significant increase in reserves at its Halfmile Lake property, one of the largest undeveloped massive sulphide deposits in the district.

Based on the results of a year-long drill program, funded by Brunswick and carried out by Noranda Exploration, a unit of Noranda (TSE), reserves in the Lower AB zone have been increased by about 20%. They now stand at 7.78 million tonnes grading 3.66% lead, 10.5% zinc, 0.09% copper and 44 grams silver per tonne. Reserves are based on a cutoff of 4.5 metres at 8% zinc. Significant results from this program include: 26.5 metres grading 3.9% lead, 10.2% zinc and 28.5 grams silver in Hole HN93-52(F) and 23.4 metres of 4.3% lead, 13.6% zinc and 36.7 grams silver in Hole HN92-53(C).

Brunswick President John Carrington told The Northern Miner that the company is trying to decide whether an underground exploration program is warranted at this time.

“We are extremely encouraged at this point but there is still some work to do before proceeding underground.”

The project, about 20 km west of the Heath Steele mine, consists of two properties referred to as the Halfmile Lake Central (Conwest) option and the Halfmile Lake South (Falconbridge) option. The property boundary cuts the deposit almost in half.

Brunswick can earn up to a 100% interest in the Central option by making undisclosed cash payments and exploration expenditures before Aug. 31, 1997, subject to a 2% net smelter return royalty escalating to 2.5% after five years of production.

It can earn up to a 100% interest in the South option by meeting certain expenditure commitments before Aug. 30, 1997.

The Halfmile Lake deposit was discovered in 1955 as a result of an airborne electromagnetic survey and a soil geochemical survey. Since the original discovery, several major exploration companies, including Kidd Creek Mines, Mattagami Lake Mines and Billiton Canada, have explored the property. These exploration efforts outlined significant base metal concentrations in the North, Upper AB and Lower AB zones.

Since acquiring the Falconbridge option in July of last year, Noranda has focused its attention on Lower AB.

David Gower, Noranda’s district geologist for the Maritimes, said that although the deposit is somewhat complex, it is still typical of the Bathurst camp. Mineralization is in an exhalitive horizon within an Ordivician-aged sequence of metavolcanic and metasedimentary rocks known as the Tetagouche Group.

The Lower AB zone strikes northeast for 250 metres, dips 50 to 90 to the northwest along a length of 610 metres, and is 4.5-21 metres thick. The sulphide mineral assemblage consists of sphalerite, galena, chalcopyrite, pyrite and pyrrhotite.

To date, Noranda has carried out 14,500 metres of drilling on the deposit, and Gower says drilling continues.