Bernic Lake: Discovery & Legacy

January 20, 2021

This article was done in partnership with the Lac du Bonnet & District Historical Society. It appeared in the January 21, 2021 edition of the Lac du Bonnet Clipper.

Ask anyone in Lac du Bonnet and they either work for Tanco, or know someone who does. Located 48 km from Lac du Bonnet, on the shores of Bernic Lake, the Tanco Mine has become one of the area’s main industries.

Township subdivision surveys of the Bird River region were completed through the winter of 1913-1914. On New Year’s Day 1914, two members of the survey crew, Harry E. Beresford and James Nicol, came upon an unnamed lake. The final report sent to Ottawa included the recommendation that this lake be named after the discoverers: BER-NIC. The name wasn’t approved until a new map of the area was issued in 1933.

A few years after the survey, an elderly prospector made a valuable discovery while on a cigarette break. The story goes that, while sitting on a survey mound, he picked up a rock and found it contained a rare mineral. While the name of the prospector and the mineral he found is unknown, his claim energized the mining community.

By the 1920s, John Nutt (of Central Manitoba Mines) sent crews to relocate the Bernic Lake claims. The subsequent discovery of tin led to the creation of Jack Nutt Mines, Ltd. A single shaft, framed with hand-hewn timbers, was dug in 1929 to access a narrow strip of pegmatite (crystallized rock containing minerals). That summer, 100 tons of ore were processed in the small plant and drilling operations found another massive pegmatite deposit 250 feet deep. The mine was forced to close October 1, 1929 as the result of a market crash and uncontrollable flooding in the shaft. The property was abandoned and eventually reverted back to the government.

The Bernic Lake claim was reopened in 1955 when demand for lithium increased. In the late 1950s, Montgary Exploration Ltd., put a shaft down 300 feet to bedrock and branched out over a mile of tunnels. The company spent $2.5 million and saw zero return. In 1962, the mine closed again.

However, the 1960s space race placed greater value on the rare minerals: tantalum, caesium, gallium and others used in electronics and rocket construction, found at Bernic Lake. In 1967, the mine reopened under the Tantalum Mining Corporation of Canada, Ltd. The Nutt shaft was repurposed for ventilation and the majority of the mining was completed under the lake. By September 1969, the plant was fully operational, “mining and milling over 500 tons of ore per day,” with over 90 employees. Their red drums, inscribed with “Tanco, Lac du Bonnet, Manitoba,” were shipped around the world for use in the electronics and aerospace industries.

In 1993, Tanco was sold to the Cabot Corporation. At the time, the mine boasted the largest tantalum reserve in North America, the greatest reserve of high-grade pollucite in the world and the distinction of being Canada’s only spodumene producer. The mine was sold again in 2019 to Sinomine Resources Ltd., based in China. After 91 years of mining the Bernic Lake site, the minerals are in lower concentrations, though Tanco Mine remains operational and is one of Manitoba’s longest-running mines, only behind the Thompson nickel mines.

References:

Aileen Oder, ed., Logs and Lines from the Winnipeg River: A History of the Lac du Bonnet Area (Steinbach, MB: Derksen Printers, 1980), 84-88.

“Low-profile mine boasts international market.” Winnipeg Free Press,June 4, 1988.

“Tanco sold.” The Leader (Lac du Bonnet, MB), February 9, 1993.

Martin Cash. “Chinese company largest cesium supplier after mine sale.” Winnipeg Free Press, August 28, 2019.

“Manitoba Operating Mines.” Manitoba Government. https://www.gov.mb.ca/iem/industry/sector/mines.html