Restoration | The Ancient Copper Mines of Michigan

Restoration | The Ancient Copper Mines of Michigan

The Ancient Copper Mines of Michigan

In the regions of Isle Royale and Keweenaw Peninsula, Michigan exists the remains of an ancient copper mining operation of almost unbelievable size.

It cannot be understated how large this copper mining operation was. Researchers who’ve looked into the ruins of the mining pits in the area have given estimates as to how much copper was extracted from the roughly 5000 pits that have been identified; 500 million pounds is a figure that’s often accepted, though other researchers have suggested that as much as 1.5 billion pounds of copper was pulled out of the pits in the area [as discussed by Drier and Du Temple in the History channel documentary America Unearthed]. To take into account, as well, farming in the region during the 19th century is thought to have wiped out traces of at least half the pits that once existed. For some perspective, ss put by William P.F. Ferguson, a long-time authority on North America’s ancient mining:

“The work is of a colossal nature, and amounted to the turning over of the whole formation to its depth and moving many cubic acres—it would not be seriously extravagant to say cubic miles—of rock.”

Map of the Michigan mines – Credit: Wikimedia Commons
Remains of a pit – Credit: James Hebert

A major head-scratcher when it comes to this ancient mining operation is that the number of copper tools found in the region, and North America as a whole, is not even remotely consistent with the amount of copper that was pulled from just this region in Michigan. You can take all the copper tools that have been discovered in all of North America and you’re still not even remotely close to the low estimates of what was taken from this area in Michigan: copper was simply an uncommon material amongst the native Americans.

Much of the copper trinkets and items associated with the natives is what’s called float-copper; which is left behind by glaciers and can be found on the surface of the ground. These small amounts of material are then worked through cold-hammering into basic shapes. High-quality copper—as in copper that’s been mined and worked—is substantially more rare, even among the already rare presence of copper throughout native American remains.

This is particularly puzzling because the Chippewa people—the natives who were discovered inhabiting the area by European settlers—had no copper culture and weren’t mining the copper pits that were discovered in their region. These people described a fair-haired race of marine-men as the ones responsible for the pits. There was also a petroglyph of a ship that was found in the area and a walrus-skin bag.

Interestingly, an enormous boom of copper swept through ancient Europe at almost exactly the time when the beginning of the mining in Michigan began. As detailed by the British Museum on a placard in their Bronze age exhibit: “From about 2500 BC, the use of copper, formerly limited to parts of Southern Europe, suddenly swept through the rest of the Continent”. The bulk of the Michigan mining is thought to have begun around 2450 BC.

Petroglyph of ship – Credit: Wakefield

What’s important to note is that, in the region where the mines are found, copper could only have been viably mined from the beginning of summer to early fall due to the severe winters. With the copper mining having been found to have come to an abrupt end at 1200 BC, that means they had roughly 1200 years to remove the copper in the area. If we look at the low estimates for the amount of copper removed, then it would mean that they were removing nearly half-a million pounds of copper every summer for 1200 years straight.

That is an absolutely staggering achievement.

Remains of a pit – Credit: Mineralogical Society of America

It’s truly difficult to imagine how a civilization could have worked so consistently at such a gargantuan scale for that incredible period of time—and again, this is a low estimate; other researchers would suggest that three times as much copper was removed—though, to note, other estimates have also been given for how long the mines were in use, suggesting they were first visited at a much earlier time. Yet, what makes this feat simply mind-blowing for many experts is how advanced the operation was.

The tools alone that have been recovered require consideration due to the immense degree of quality and consistency that can be found throughout them. In discussing this, an expert on the Michigan mines, sa, remarks: “One is involuntarily amazed at the perfection of workmanship and at their identity of form with the tools… The sockets of the spears, chisels, arrowheads, knives and fleshers are, in nearly all instances, formed as symmetrically and perfectly as could be done by the best smith of the present day, with all the improved aids of his art”.

Position of the pits – Credit: Bowen & CO

As well, extremely large amounts of these high-quality tools have been discovered. A 1000 tons were recovered from one dig area on the north shore of Isle Royal, and ten wagon-loads of hammers were taken from a dig near Rockland in 1840.

The miners also somehow located and precisely mined the 5000 pits that have been examined throughout the 150-mile area where they reside, and in nearly all of these cases, the copper would have been underground and extremely difficult to locate. Yet, they somehow managed to find the location of this hidden copper and create sophisticated mining pits; a number of which traveled 60 feet below ground through solid granite. These pits utilized advanced irrigation systems to flush out debris with deep trenches running for hundreds of feet.

Extremely intense heat was utilized at the top of the copper veins to bring the rock to extreme temperatures before it was then doused with water so that it would fracture. Yet how they managed to create and direct such heat may exist as the biggest mystery. Lighting and stoking fires would prove ineffective as only a very small amount of heat from a fire travels down beneath it. What is known is that the workers were also using a specialized super-heated vinegar mixture in the process which is thought to have been a part of their technique to fracture the veins. Still, no one can determine how exactly they managed to do what they did.

Remnants of one of the mines – Credit: James Hebert

The copper that comes from these Michigan mines is of particular interest due to its unbelievable purity. It’s been tested to be 99.92% pure; which is why it’s known to be the purest in the world. Also, taking into consideration the way it was formed to make it this pure, via natural earth mechanisms, it has a very unique signature.

These things are particularly important to note when trying to flesh out where all the copper went to. Such unique features would be hard to safely distinguish after the copper was crafted into a tool, though they would remain clear in the ingots that the workers at the mines would have created outside of the Michigan pits.

The largest discovery ever of copper ingots comes from the Uluburun wreckage; a ship that sank in the late 14th century BC just south of Uluburun in Turkey. Ten tons of the copper ingots were found on the ship, which is more than every other copper ingot in every museum and collection, public or private, combined. As discovered by the Hauptmann study, the ingots composition doesn’t match the composition of what’s expected in ingots crafted in Europe, Africa, or Asia. They were instead found to contain angular-shaped inclusions of iron-silicate as well as isocrite, along with having a unique porous structure, and they were also found to be 99.5% pure; all things which point to the ingots having been created onsite with naturally-formed slag: perfectly consistent with what would be expected of the Michigan ingots.

Copper ingot from Uluburun wreckage – Credit: Museum of Underwater Archaeology

Overall, when looking at the scale, the duration, the consistency, and the extent of the copper mining operation that took place, it only seems reasonable to have been achieved by one or more of the great civilizations that operated out of the near east or Europe, likely a string of similar or chain civilizations that took over after each other: in doing so inheriting the knowledge of the former’s mining resources, routes, and techniques.

A Minoan fresco depicting a settlement and their ships – Credit: Dirk Herdemerten

In regards to who exactly, the Minoans appear to be one of the most likely candidates. They were known to have been incredible seafarers who controlled the copper trade in the Mediterranean thousands of years ago, and they were also known to have been flourishing between 2600 to 1100 BC—the Michigan mines were thought to have been at their height from 2450-1200 BC.

As well, a number of remnants tie them to the Americas. A cave on the Ohio River, known as the Cavern of Glyphs, contains images of clothed figures that researcher Harold T. Wilkins, in describing them, says they, “singularly recall the dress of the Minoans, as seen on the frescoes at Knossos in Crete”. The unique mosaic tile technique used by the Olmecs at La Venta can also be found at Knossos in Crete. Additionally, a pot, exactly matching the style found at Knossos was unearthed in Louisiana. Whether these finds act as true evidence of a Minoan presence in the Americas remains up for debate, though along with the Minoans connections to seafaring and the copper trade and the corresponding dates of their rise and the mines, they would appear to make the Minoans a stronger candidate for being a civilization involved in the Michigan copper trade.

Another piece of evidence is the Newberry tablet; a stone tablet accidentally unearthed by two lumberjacks in Michigan at the end of the 19th century. They decided not to discard it, alerted the man who’s property they were working on, and eventually it began to draw more and more attention to the point where an expert came in. But the expert immediately disregarded it under his rule that there was no trans-Atlantic contact before Columbus. So, the farmer, who’s land it was found on, tossed it into a ditch in his field—where it’s been almost ruined by decades of rain. However, decades later it was recognized, by reviewing pictures of the tablet, that the writing upon it was Linear A; an extremely exotic script only found on the isle of Crete and associated with the Minoans. How two lumberjacks—or anyone—in the 19th century could have gone about forging a script that wasn’t properly known about until the next century and still remains undeciphered today is a very critical question when it comes to the authenticity of the Newberry tablet.

A recreation of the inscriptions found on the Newberry Tablet – Credit: Roger Jewell

One extra boon is that an ancient harbor was discovered in 1922 by William Ferguson on Isle Royale near the north coast—Isle Royale being a major area in the ancient mining operation. What he discovered was the remains of a pier that had measured 1600 feet in length, indicating that it was used by multiple large ships. However, it could have just been 60 feet because the most important detail is that the Native Americans only ever used small canoes: they never built piers.

The general point is that it seems to be well-beyond belief to assume that the small and scattered tribes who existed in the area must have been responsible for the mines based on the refusal to accept that the Americas were not being visited by civilizations before Columbus—despite their being ample evidence suggesting otherwise. The civilizations that existed in the ancient near east and Europe are the only candidates who’d have the power, technology, resources, and purpose for undertaking such an extensive operation.

Remains of a pit – Credit: John Wanserski


Hauptmann, A., Maddin, R., Prange, M., “On the structure and Composition of Copper and Tin Ingots Excavated from the Shipwreck of Uluburun”, American Schools of Oriental Research, Bulletin No.328 pgs.1-30, Nov.2002

Martin, S.R., “The State of Our Knowledge about Ancient Copper Mining in Michigan”, The Michigan Archaeologist, 31 (2-3):119-138, 1995

Martin, S.R., Wonderful Power, The Story of Ancient Copper Working in the Lake Superior Basin, Wayne State Univ. Press, Detroit, 1999 (ISBN 0-8143-2843-1)

Joseph, F. (2016, July 07). Copper Mining in Ancient America. Retrieved January 16, 2018, from

Rydholm, F., “Old World Copper Miners of Ancient Michigan”, The Barnes Review, July/Aug, 2002

Thurner, Arthur W., Strangers and Sojurners: A History of Michigan’s Keweenaw Peninsula, Wayne State University Press, 1994

Hauptmann, A., Maddin, R., Prange, M., “On the structure and Composition of Copper and Tin Ingots Excavated from the Shipwreck of Uluburun”, American Schools of Oriental Research, Bulletin No.328, pgs.1-30, Nov.2002

Courter, Ellis W., “Michigan’s Copper Country”, (State of Michigan Department of Environmental Quality), p. 136-137, 1992

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