2017 Mining History Association

 

ON THE WAY TO THE MHA...
A Visit to the
Kennecott Mines
National Historic Landmark,
Wrangell-St. Elias National Park
And Preserve, McCarthy, Alaska
June 10-14, 2017

 

Johnny and Dawn Johnsson
Dick And Elna Hauck

PHOTO GALLERY 3 OF 6


Narrative continues from Gallery 2…

The mill was fed by two aerial tramways bringing copper ore from 4-5 interconnected mines some 4,000 feet above on Bonanza Ridge.  These mines, the Bonanza, Mother Lode, Glacier, Jumbo, and Erie were linked by a combination of aerial tramways or some 70 miles of underground tunnels and workings.  Miners’ bunkhouses and mine facilities in various stages of condition are way up on the ridge and may be hiked to with or without guides during the tourist season if someone has the ability and time. 

Two aerial tramways from the Jumbo and Bonanza Mines descended to serve the mill complex.  The remains of the tramway terminus mark the beginning of the mill tour descending down through the 14-story heavy timber structure.  You can see the grizzlies where tramway buckets were dumped to feed the two extant Buchanan jaw crushers.  The mill incorporate several conveyors and bucket elevators, but mostly uses chutework to distribute mill feed down through the levels of the gravity concentrator.

Descending further down steep, narrow, and dark stairways we were able to see 400-ton ore bins, a trommel, some of the coarse jigs, and vibrating screens.  Due to safety concerns, not every area of each mill floor is accessible.  You need to have decent mobility, balance, and stamina to take this tour.  Hi-grade ore was hand-picked and sent down steep external chutework for direct shipping to the company smelter in Tacoma, Washington.  Drive belts and pulleys for the Symons Disc Crusher and Traylor Roll Crusher were impressive. 

Narrative continues on Gallery 4…


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The fourteen-story Kennecott Copper Concentration Mill (ca1911) as seen from the north.  The interior of the mill and several other buildings can only be visited on a licensed guided tour (fee charged).  There are steep, dark steps and many tripping hazards in the Mill.  You must be in shape and be careful!

Two aerial tramways brought copper ore from the mines high on the northeast ridge nearly 4000 feet above the Mill. The tramway terminals are on the top of the Kennecott Mill.  The terminal at the right had collapsed after the site was abandoned in 1938.  It is being restored by the National Park Service.



The first tramway transported ore from the Bonanza Mine to this Tramway Terminal (ca1908, modified ca1912).  It is under restoration.


The second Tramway Terminal (ca1912) received the ore from Jumbo and Glacier Mines.


Copper ore in its limestone host rock dropped through 3.5 inch grizzlies into hoppers feeding two Buchanan jaw crushers.  You can see the waffle pattern of the fixed jaw crusher plate.


A view of the drive wheel on a Buchanan crusher.



(Above)  1200 tons per day of rich copper ore containing malachite, azurite, chalcocite, and covellite were processed through the Mill.  The best ore contained 60-65% copper.

(Left)  These massive timbers supported the 400-ton crushed ore bins.  Next the ore was passed through a trommel.  Oversize material went to conveyors where the highest grade ore pieces were hand-picked for direct shipping to the smelter in Tacoma, Washington. 


Unpicked material from the trommel passed to the Symons disk crusher.


Undersize material from the trommel and the ore from the Symons disc crusher were passed over the vibrating screens.  Undersized material from the screens was sent to the concentrating tables.

 

All of the processing equipment in the Mill was operated by belts and pulleys from overhead drive shafts.


Chutes and gravity were used to direct dry ore through the Mill.  Vertical bucket elevators were used to lift dry ore from the crushing area to the vibrating screens.
 

Photos by Johnny and Dawn Johnsson


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