The Pittsburgh and Boston Company had the distinction of sinking the very first copper shaft in the Copper Country, into the hard rock along Hay’s Point in Copper Harbor. This early venture was a disaster, costing investors over $20,000 in the process. But they were not deterred, and turned towards a second piece of land south of Eagle River along the great soaring bluffs of the Cliff Range. This second attempt was a different story all-together, resulting in the first profitable copper mine in the Keweenaw. This would be, of course, the famous Cliff Mine.
The Cliff’s success was due mainly to its abundance of mass copper – large single pieces of copper ranging in size from a ton to more then a hundred. Three-quarters of all copper mined at the cliff were in the form of these massive boulders, all of which required very little if any milling before being sent out east to smelters. However copper in a more traditional form was also mined here, which required the construction of a small stamp mill on-site to process it.”