Capstone Mining Corp. Oct. 11 reported that its Minto Mine in the Yukon produced 3,400 metric tons of copper during the third quarter, a 23 percent drop from the 4,400 metric tons produced there during the second quarter, and a 38 percent decline from the 5,500 metric tons produced in the first quarter.

The company attributes this drop in copper production to mine sequencing changes to support ext...