The Minto mine, located in the Selkirk First Nation’s Territory in central Yukon, has ceased operations, TSX-V-listed owner Minto Metals announced on Saturday, stating that it had handed over care and control of the site to the Yukon government.

The company’s statement did not provide much detail about its decision to halt operations, besides CEO Chris Stewart expressing disappointment at the decision and stating that the market would be updated regarding its future “as soon as possible”.

"Ceasing operations at the Minto mine was an extremely difficult and disappointing decision, that was not taken lightly. We are acting responsibly in coordination with the Yukon government to avoid any damage to the environment.”

Minto noted that it had invested a significant amount of money into improving the water treatment plants at the mine, doubling its water treatment capacity. As a result, both plants are currently operating at full capacity for spring freshet.

Yukon Energy, Mines and Resources Minister John Streicker said in a statement on Saturday that the government had hired JDS Mining as the contractor to ensure environmental protection was maintained at the site.

Minto was issued an inspector’s directive last month to take action to prevent overfilling of the tailings storage facilities at Minto during the spring snow melt. The company was ordered to begin transferring water into one of the previously mined openpits if available storage capacity in the tailings management facility dropped below 300 000 m³.

"While transferring water to this pit is not part of the current water licence, the risk is low as it was previously mined, and offers the best choice to protect the integrity of water and tailings storage facilities in advance of the spring snow melt," Streicker said at the time.

Minto previously said that it was in a much better position this year to handle excess water that would be received during the spring freshet.

Last year, more than 1.4-million cubic metres of water was discharged, which constitutes more than double what was cumulatively discharged over the prior seven years. The snowpack last season was 417% above normal.

Meanwhile, London-listed Pembridge Resources has warned about its ability to continue as a going concern, following the suspension of the Minto mine.

The company has been informed that Minto is unlikely to be in a position to repay about C$2-million, C$250 000 of which is payable in instalments during the remainder of 2023.

The Minto receivable is considered critical to the cash flow of Pembridge for the next 12 months, noting that it has $350 000 of short-term liabilities and $126 000 of cash as at today.

The investment in Minto and the Minto receivable represents more than 90% of the company's assets.  

Minto CEO and chairperson Gati Al-Jebouri has resigned from his position of director and chairperson of the audit committee of Minto on May 12, owing to the conflict of interest arising from the fact that the company has a claim against Minto.

"It is very disappointing that Minto has been unable to raise capital and that Minto has suspended operations as of May 13, 2023. Minto is unlikely to be able to repay Pembridge as scheduled, despite all the support provided to Minto by its shareholders, including Pembridge.

“As a result of this material uncertainty to the company, the board has no option but to carefully assess the financial viability of the company, consider delisting from the London Stock Exchange as well as obtain appropriate professional advice on the restructuring and insolvency options available.  

"The board will consider every feasible option available to ensure that any losses are minimised for all creditors and other stakeholders of the company,” said Al-Jebouri.

The mine opened in 2007 and has produced about 500-million pounds of copper since then.