History of Our Plant

The discovery of silver in the Town of Cobalt in the early 1900s gave birth to many mines. Small operators had no refining, smelting or even milling facilities and relied exclusively on major mining companies for those services. Shippers of ore had no method of ensuring quality and representative sampling and accurate assaying of their production. This resulted in questionable premium formulas for product received.

In 1909, two engineers named Campbell and Deyell designed a method of sampling ores and concentrates. Through a process of comminution or fragmentation, they brought ores to a uniform blended mesh size allowing representative sampling and accurate assaying of large volumes of ores. Extracted metallic silver was poured into bullion bars and sold on the market.

The testing operation was successful until 1917 when failing silver prices slowed the flow of feed and made the enterprise uneconomical. There were many operators left in the area who still needed the service. As a consequence, the mining industry asked the provincial government to operate the plant. The industry's efforts were rewarded and the government assumed control through its Temiskaming and Northern Ontario Railway in 1919. In 1921, two years later, the Ontario Department of Mines (now MNDM) established the Temiskaming Testing Laboratory (TTL) in Cobalt to provide a specific service to the mine operators of the area. Because few of the individual mines were large enough to justify the cost of operating their own assay offices and other specialized equipment, it was decided that these services could be performed for all of them at a minimal cost. Since then it has been operated as a service to government agencies, exploration and mining companies. The TTL has maintained an excellent reputation for its bulk sampling and processing of ores, particularly silver ores.

The PolyMet facility was first constructed in September 1913, on the charred ground where the Cobalt Hotel once stood, at a cost of $37,000. The first level of the building contained a farmer's market that opened onto the station grounds. In May 1914, the four-storey concrete structure was completed. The bottom floor still contained a market hall and the main floor, which was entered from Presley Street, housed the municipal offices with council chambers, a courthouse, and a jail. On the top floor was a large assembly and dance hall complete with dressing rooms. The square tower on the southeast corner housed the town bell and was also used for drying the fire hoses. In 1941, the original Temiskaming Testing Laboratories, whose building had recently burned down, re-established in the quarters it occupies today on Presley Street in Cobalt. The building was extensively renovated and updated over the years by the Ministry of Northern Development & Mines as a technically advanced bulk sampling and testing station for minerals and precious metals.

The laboratory assayed and sampled all the high-grade ores and concentrates, shipped them to the smelters on behalf of the producers, and performed other similar services to keep the mines operational. In the 1990s the Ontario government decommissioned the operation due to reduced silver mining activity in the area, which no longer adequately supported its presence in the area. The Ministry of Northern Development and Mines has since relocated its public services assay laboratory to Sudbury, Ontario, now operating under the name of Ontario Geoscience Laboratories.

Polymet Labs Inc. purchased the former TTL building in August 2000 and began its operation as an Assay Laboratory and Bulk Sampling, Crushing, Grinding, Processing, Upgrading and Smelting Plant.