TORONTO (miningweekly.com) – The damaged semi-autogenous grinding (SAG) mill transformer at British Columbia-based Copper Mountain Mining’s flagship mine was replaced late on Friday and the mill was back in operation by 18:00, a day earlier than expected, the company said on Wednesday.
Site maintenance personnel were able to successfully replace the damaged transformer with identical transformers from ball mill No 1.
Operations over the Canadian long weekend, with the SAG mill and one ball mill, were better than expected and operated at an average rate of 1 100 t/h or an average of 25 400 t/d.
Copper Mountain said the supplier, ABB Transformers, and an independent third-party consultant were evaluating the exact cause of the failure; however, preliminary testing had indicated that damage was limited to one set of coils in the transformer, which could help to reduce the repair time.
The damaged transformer was trucked to ABB's transformer repair facility in Edmonton, Alberta, and ABB had sent a technical specialist from its plant in Italy to oversee dismantling of the damaged transformer, which was scheduled to take place on Tuesday.
ABB's transformer facility had ordered the raw materials necessary to manufacture a replacement set of coils, which would be flown to Edmonton. The repair of the one set of coils was expected to take two-and-a-half weeks.
Copper Mountain had instructed ABB to manufacture a full set of coils for the transformer for an estimated cost of $125 000 to ensure additional coils are on site and available at all times.
CEO Jim O'Rourke on Friday said immediate metal production would be impacted.