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Touring Colorado’s Argo Gold Mine & Stamp Mill

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The colossal seven-storey Argo Gold Mill -- which opened in Idaho Springs, Colorado on April 1, 1913 -- was once reputed to be the largest gold processing mill in the world. The "Mighty Argo," which could handle up to 300 tons of ore per day, initially processed ore from the Gunnell, Prize, Ophir, and Poco mines and ultimately serviced over 200 mines within Clear Creek and Gilpin Counties.

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Entry and egress from the Newhouse Tunnel portal (later renamed the Argo tunnel), located directly adjacent to the mill, was provided courtesy of a twin 18-inch gauge railway track laid with 30 pound rail for the first 13,100 feet and a single track for the remainder of the distance. Two 7-ton Westinghouse electric locomotives hauled the ore and miners back and forth in 3-ton box cars.

A dedicated 12 inch by 18 inch drainage ditch -- driven on a grade of one-half of one percent -- cut into the tunnel floor was designed to carry water out of the labyrinth of inter-connected mine workings and into the Clear Creek River below. Unfortunately, the continued uninterrupted discharge of acidic, and highly toxic metal-rich water from the 4.16-mile-long Argo mine tunnel, some five decades after the mine closure, necessitated the construction of a dedicated water treatment plant -- situated just to the west of the mill -- which came on-stream in 1998.

The 21,968-foot-long Argo tunnel closed in January 1943, when a powder blast on the lateral to the Kansas shaft flooded the Argo Mine, killing four miners who were working on a tunnel extension. The entrance to the Argo Mine is currently sealed so if you’re anticipating an extensive hard hat-based subterranean adventure this may not be the destination for you.

Visitors to the Argo, which celebrated its 121st anniversary in 2014, can explore the Double Eagle Mine (a short adit situated just above the mill) and then take a self-guided tour through the mill which traces the path of the ore processing operation, from the ore bins and stamp room, descending past classifiers, amalgamation tables and flotation cells to the final cyanide leaching process at the foot of the mill.

The behind the scenes glimpse of the gold and ore processing operation in the venerable and somewhat dilapidated stamp mill is by far the strongest element of the tour, though kids will no doubt enjoy the gold panning when, after a quick crash course in correct panning techniques, they may be lucky enough to hit pay dirt.

Additional Information: Argo Gold Mine & Mill, 2350 Riverside Dr., Idaho Springs, CO 80452 • Tel: (303) 567-2421 • Admission: Adults $16 • Children (6-12) $8 • Children under 6 Free •