operations

The Minto underground mine uses primarily long-hole open stoping. Access to the underground workings is via a single service and haulage ramp. Crushing, grinding and flotation is used to produce copper concentrates with gold and silver credits. The gold and silver at Minto has been sold in a streaming transaction to Wheaton Precious Metals (formerly Silver Wheaton) for the life of the mine.

Run-of-mine ore is stockpiled on surface depending on the copper grade of the material. A loader transports the stockpiled material to the primary crusher which feeds a gyratory crusher. The crushed product is then fed to a conventional grinding and flotations circuit to produce a bulk copper concentrate. The concentrate is thickened and filtered to produce product suitable for transport. The product has historically been transported by truck to Skagway, Alaska for export.

The Minto Mine commenced commercial production in October 2007 at 1,800 tonnes per day with a four year mine life, at the time. The mine is accessible via the Klondike Highway to the Minto Landing on the east side of the Yukon River, where the mine has historically operated a barge across the river in the summer months and constructs an ice bridge for accessibility during the winter months. For approximately six weeks in each of Spring and Fall there is no access to the mine via ground transportation so concentrate was produced and stored on site until the river becomes accessible.

The Minto deposit is spread over a series of high grade areas interspersed with large deposits of low grade material. The mine plan was designed for the highest grade deposits to be mined sequentially in a series of small pits supplemented with additional ore from underground.

In 2017, Minto extended its mine life through mid-2021 based on commodity price improvement and a renegotiated gold stream. The decision to extend the mine life resulted in several mine plan sequencing changes.

In October 2018, Minto was placed on temporary care and maintenance to preserve it's value while Capstone continues to explore value maximizing alternatives. Refer to October 11, 2018 news release for more details.