New Mexico Mineral Symposium — Abstracts

For well over a century, the Keweenaw Peninsula has served as a home to a multi-billion-dollar copper industry. The roots of mining go back several thousand years when Native Americans first discovered the nearly pure copper and silver deposited in fissure veins cutting across the Keweenaw Peninsula. Along the sparsely vegetated shores of Lake Superior and inland lakes of the post-glacial period, the Native Americans mined the red metal for possibly 10,000 yrs. The malleable copper was easily shaped into tools and other valued implements and was traded across North America and perhaps beyond.

As an avid scuba diver and mineral collector for over 25 yrs, I was drawn to Lake Superior because mineral collecting for fine specimens on the Keweenaw was becoming an activity of the past. With the closing of many old mines and the crushing of rock piles, it was becoming exceedingly difficult to obtain high-quality specimens. I was spending countless hours sifting through old geology maps of the Keweenaw and studying the copper-bearing series along its length when one day it struck me—why not follow the fissure veins into Lake Superior and see where they cross the offshore shallow reefs? So in the summer of 1991, I concentrated my efforts on a large reef between the old seaports of Eagle River and Eagle Harbor and realized within a short period of time it was well worth the effort.

During July of 1991, I discovered the largest piece of fissure vein copper, 30 ft offshore of Great Sand Bay just northeast of Eagle River, Michigan. It measures 19 ft long, 8 ft wide, and weighs approximately 17 tons. Salvage permits had to be obtained from the Michigan Department of Natural Resources and the U.S. Army Corps of Engineers before the recovery project could begin. We had two nylon straps specially made to support the copper and to prevent damage to the natural color during the lift. A single 20-ton hydraulic jack was used to lift the copper high enough to slide the straps underneath. Then the U.S. Army Corps of Engineers' barge and crane were used to lift the boulder from where it had been resting for thousands of years.

The state-owned boulder now resides in the historic Quincy mine 1894 hoist house just north of Hancock, Michigan, and will be curated by the A. E. Seaman Mineral Museum. It is the largest piece of natural native metal ever recovered from a body of water and resides on probably the largest hydraulic mineral display stand in the world! Hopefully, its final destination will be in the main foyer of the new museum to be located in the blacksmith and machine shops of the Quincy mine complex, which is slated to break ground in 2005.