Bob Barron steadies the straps before the hauling begins. PHOTO
BY BILL SILER
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Unburied Treasure
by Robert J. Barron
A large group of spectators waited for the U.S. Army
Corps of Engineers’ tug and barge at the Lilly Pond dock inside the breakwall
of the Portage Canal North Entry in Michigan’s Upper Peninsula.
A flatbed semitrailer truck waited, too, to carry to its new home the spectacular
curiosity that the crowd anxiously wanted to see.
No wonder the interest. How often is an almost 20-ton boulder of nearly
pure natural copper pulled from the bottom of Lake Superior? Almost never,
I can tell you from personal experience. I’m the one who found this copper
chunk ... and it took 10 years, a mountain of forms, part of a federal
grant and a U.S. Army Corps crew to raise it.
But first I had to find it....
For well over a century, the Keweenaw Peninsula served
as home to a multi-billion dollar copper industry. The roots of mining
here, though, go back even further, thousands of years. Native people first
discovered the nearly pure copper and silver deposited in fissure veins
within the local basalt matrix. The malleable copper was easily shaped
into valued tools. Along the sparsely vegetated shores of Lake Superior
and the inland lakes of the post-glacial period, the ancients mined the
red metal - some believe for about 10,000 years - and it was traded in
a huge area of North America and perhaps beyond.
As both a diver and an amateur geologist, I always knew I’d have an excellent
chance of discovering copper, silver and associated minerals if I could
just spend a summer diving on exposed basalt reefs in Lake Superior offshore
along the Keweenaw Peninsula. In 1991, I got the chance to test my theory.
Usually, Lake Superior warms enough for wet-suit diving by mid-July, when
I had time off. The area that I wanted to cover would be too large to simply
swim through. What I needed was a reliable crew member to tow me around
the Eagle River Shoals of Great Sand Bay on a 60-foot ski rope behind my
little 14-foot open boat. Don Kauppi of Copper Harbor, always interested
in trying something new, agreed to team up for the summer.
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In theory, we should discover all decent-sized fissure veins of copper
as long as we paralleled the shore and the basalt reef. The theory held
and within a few hours of “trolling,” I had crossed several veins of copper
littered with pieces of native metal. Here was a discovery for which those
early native and European prospectors might search their entire lives.
I was awed by the knowledge that human hands had never touched these copper
specimens.
Each time we went out, we found new copper veins - some with minute attachments
of silver. Then one day, Don towed me over a nicely sculpted piece of copper
about 6 feet long and 3 feet high. What a beauty! As per my standard procedure,
I let go of the tow line and trailed the vein. Loose copper ran richly
along its length. As I followed the vein toward open water, I scanned for
more metal. There remained only about 50 yards of exposed basalt before
the vein would dip into the deeper sands and sediments of the lake bottom
and disappear from sight.
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A variety of copper crystal forms can be found in abundance in the Upper
Peninsula, like these twinned tetrahexahedral crystals in the A.E. Seaman
Mineral Museum taken from the Central mine, Keweenaw County.
PHOTO BY GEORGE W. ROBINSON
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Suddenly, I lost sight of the vein under some boulders. Well, that’s the
end of that, I thought. Then I noticed the edge of something flat and large,
not a normal boulder. It was copper! An enormous hunk of pure metal - well
camouflaged by a layer of the brownish organic material covering the lake
bottom.
As I hovered over it, I tried to estimate its length. Any diver will tell
you that your mask magnifies underwater objects. So this must be smaller
than I’d first thought. But a few minutes of examination had me shooting
to the surface faster than normal (looking back, I’m glad I was in only
30 feet of water). I shouted excitedly to Don. When he came close enough
to decipher my clamoring, Don knew it was something big. But as we headed
home for the day, he doubted that my descriptions could be accurate.
The next day we went back, tape measure in hand, and I carefully measured
the copper - 19 feet long, more than 8 feet wide and averaging 18 inches
thick.
Wow! A copper “nugget” weighing about 20 tons and apparently detached from
the vein. Now, could we get it out?
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Bob Barron, discoverer of an enormous copper boulder under
Lake Superior along Michigan’s Keweenaw Peninsula, gets a look at his 17-ton
baby as it’s brought aboard a U.S. Army Corps of Engineers vessel.
PHOTO BY JIM JACKMAN
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First we needed salvage permits from the Michigan Department of Natural
Resources and the U.S. Army Corps of Engineers. Don and I set to work filling
out forms. Several weeks and many phone calls later the disappointing decision
came through: leave the copper on the bottom as part of a newly enacted
underwater preserve meant to protect the few remaining shipwrecks that
dot the Keweenaw Peninsula. This great blow killed my hopes to raise my
copper treasure.
Five years later, in 1996, I started a new job designing exhibits for the
A.E. Seaman Mineral Museum on the campus of Michigan Tech University (MTU)
in Houghton. One day I mentioned our copper discovery to Stan Dyl, director
of the museum. I asked if I could use the museum as leverage to re-apply
for salvage permits.
Stan thought it was an excellent idea. The copper boulder could become
part of the museum’s collection, where it would be properly curated and
put on display.
Nearly five more years of persistence and processing secured the proper
permits. The DNR - the owner of my discovery - agreed to lend the copper,
more or less permanently, to the museum.
From the Corps of Engineers I needed more than a permit. The Corps’ barge,
frequently at work in our area, could raise the copper’s tonnage.
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