By 1870, the copper resources had been largely worked out.

Estimates of known and undiscovered copper resources total nearly 60 million metric tons of copper.

This mine is still today one of the world's largest copper resources.

Lesser reasons were to help dispel negative beliefs about the state and to investigate copper resources in the Upper Peninsula.

They found only minor copper resources, rather than the gold they anticipated, and later described the terrain as very rugged.

Msiri's control of south-east Katanga and its copper resources was consolidated.

Extraction of the copper resources was rendered difficult by navigation difficulties at the river's mouth.

By 1857, copper resources became scarce and the area's economic focus shifted to timber harvesting.

Despite over 90 years of intensive exploitation it remains one of the largest known copper resources.

This would be one of the largest copper resources ever found in North America.