St Barbara wants to raise tailings dam at Touquoy gold mine in Nova Scotia

Touquoy gold mine, Nova Scotia: Credit: St Barbara

St Barbara (ASX: SBM) could be forced to suspend operations at the Touquoy gold mine in Nova Scotia soon, should it fail to receive provincial government approval for a proposed tailings capacity expansion by early August. The mine’s current tailings capacity is expected to be exhausted in mid-September 2022.

The Touquoy open pit mine is part of St Barbara’s Atlantic operations that includes three other projects nearby at Beaver Dam, Fifteen Mile Stream and Cochrane Hill. The combined mineral reserves for the Atlantic operations are estimated at 1.6 million oz. at a grade of 1.0 g/t gold. Together they have an estimated mine life to 2030.

The Australian miner first began mining at Touquoy in 2017, reaching commercial production a year after. The processing plant at Touquoy is a conventional carbon-in-leach (CIL) circuit with a nominal capacity of 2 million tonnes per year.

In 2020, St Barbara began the provincial permitting process to convert the Touquoy open pit into a tailings management facility (TMF) upon completion of open pit mining. This longer-term strategy for tailing deposition was implemented to extend the life of the Touquoy mine, following similar paths to Beaver Dam and Fifteen Mile Stream.

However, late in the process, the Nova Scotia Department of Environment and Climate Change (NSECC) sought further clarification on aspects of the in-pit tailings deposition application, which impacted the timeframes for the company’s in-pit tailings solution. At the current rate, construction work on the in-pit tailings infrastructure will not be completed by the time the current TMF capacity is exhausted.

The company therefore elected to make an application to raise the existing tailings dam as an interim solution while the in-pit deposition matter is settled. The capital cost for the tailings lift is approximately $4.2 million and will extend the life of the Touquoy operation until the end of fiscal 2023.

A permit application to lift the dam was then submitted, but the timeframe for a decision was set at early August 2022. Should approval of the permit not arrive by then, there would be insufficient time to allow for the construction of the raise, leading to the Touquoy operation being placed into care and maintenance.

The potential tailings dam raise has alarmed environmentalists, according to reports by CBC, as the industrial permit is considered separate from the normal environmental assessment process. “Raising a tailings dam puts it more at risk of breaking and this decision is going to be made behind closed doors and you’ve really got to question it,” said Karen McKendry, wilderness outreach co-ordinator for the Halifax-based Ecology Action Centre, in a CBC interview.

At of this moment, the Nova Scotia environmental department is still reviewing St Barbara’s proposed interim tailings solution.