1997 Mining History Association Field Trip

 

Keweenaw Peninsula Copper Mines

Houghton, Michigan

June 8, 1997
(Reconstructed 2020)

PHOTO GALLERY 1 of 4

 

The dozens of mines of the Michigan Copper Country were located inland along the spine of the Keweenaw Peninsula which juts out into Lake Superior.  Highway 41 from Houghton to Copper Harbor follows trend of the copper lodes.  The processing mills and smelters were located along the Lake Superior shoreline and along the shores of Lake Linden, Torch Lake, and the Portage Channel between Houghton and Hancock.  The first photo gallery, below, starts with the processing sites.  The subsequent galleries cover the mining areas from Calumet, headquarters of the Calumet and Hecla Mining Company, to Copper Harbor and Fort Wilkins, site of the first copper mine. 


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The last steam-driven stamp in the Copper Country at the site of the Ahmeek Mill alongside Torch Lake in Tamarack City.  The Ahmeek was the last and most modern of the ore processing mills.  CLICK HERE TO SEE A CLOSEUP OF THE LAST SURVIVING STEAM STAMP.

The line of stamps at the Ahmeek Mill extended nearly to the shoreline of Torch Lake.  Several other mills were located along Torch Lake including the last mill of the Quincy Mining Company.

The town of Lake Linden was the location of the Calumet Stamp Mill (1891-1944) and the Hecla Stamp Mill (1891-1921).The prominent foundations shown above are the footprints of the original mills. Starting in 1909, additional regrinding and flotation mills plus a leaching plant were added on the shoreline of the lake in front of the Calumet Mill to increase copper recovery from ore and reprocessed tailings dredged from the lake. All of these facilities closed in 1953. (Annotated Google Earth image)

Tailings from the Calumet and Hecla mills were called stamp sands after the steam driven stamp milling process.  After the copper had been recovered, they were disposed into Torch Lake.  The sheer scale of the mills can be appreciated in this 1906 photo taken from the tailings in the lake.  (Courtesy, Library of Congress)


Tailings from the milling process were discarded in Torch Lake.  The lake can be seen behind the base of a Dorr thickener at the Calumet Mill site.  The process flow can be seen below.


The foundations of the steam stamps in the Hecla Mill can be seen at the right.  The row of round objects are the bases of 3-deck Dorr thickeners used to treat the fine particles of pulverized ore.

The flow of the ore through the Calumet and the Hecla Mills started at the upper right where ore brought by trains from the mines was dumped into a rock bin.  The ore was next pulverized by steam stamps.  Copper was recovered using Woodbury jigs and Wilfley shaking tables.    Fine particles called slimes next went to three-decked Dorr thickeners before tailings were disposed in Torch Lake.  Flotation and leaching processes were added to the mills to boost copper recovery as ore grades declined.  (US Bureau of Mines)

 

The Quincy Dredge sits abandoned along the shore of Torch Lake.  As ore grades declined in the mines, the companies dredged and reprocessed the tailings from earlier mills.  Dredging continued for years after the mines were shuttered.

 

The Houghton County Historical Museum is located in an old office building in the park adjacent to the Calumet and Hecla Mills.


Photo Credits: Johnny Johnsson, Mark Langenfeld, and Mike Kaas

CLICK HERE FOR PHOTO GALLERY 2 OF 4



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