Sumpter Valley Gold Dredge, Mining museum and dredge in Sumpter, United States.

The Sumpter Valley Gold Dredge is a floating gold-mining machine with a dark brown wooden hull and cabin, a tall rusty metal gantry with cables and a hanging hook on top, and a long inclined conveyor covered in pale tarp rising to the left. It dug with large buckets that lifted gold-bearing earth into the machinery, then sent the waste out the back by a stacker. Built on a shallow hull, it carried its own pond of water with it.

Gold was found at Sumpter in 1862, and three dredges worked the valley between 1913 and 1954, together travelling more than 8 miles (13 km) and recovering $10 to 12 million in gold. Sumpter No. 3 was built largely from parts of the first dredge, which had stood idle for ten years. The last dredge closed in 1954 more than $100,000 in debt, having produced $4.5 million at $35 per troy ounce.

The dredge's name comes from Sumpter Valley, where gold was found in 1862 and three dredges worked between 1913 and 1954. A three-man crew ran it, with 17 more for maintenance and office work; most had only the Fourth of July and Christmas off. Workers reported hearing the ghost of Joe Bush when the machine stood idle.

The best way to explore the machine is during daylight, when you can see the details of all the steel parts and mechanisms clearly. It's wise to wear comfortable shoes, as moving around and climbing through the dredge involves uneven surfaces and stairs.

Visitors can see the original bucket-line system, a network of buckets that scooped material from the ground and lifted it into the processing machinery above. This technology was an engineering feat at the time and allowed the dredge to handle tremendous volumes of rock each day.