Treadwell Mine Complex was once the largest low-grade gold mine in the world

Treadwell saltwater pump house as it looked in 2012. A new roof was put on the building in 2013 and the building was secured.

Treadwell was a company mining town just south of Douglas on Douglas Island. Associated with the town was the Treadwell Complex — four interlinked mines strung out along the island’s shore. During its lifetime, the Treadwell Complex was the largest low-grade gold producer in the world, extracting over 3 million ounces of gold.

In addition to production facilities, the complex provided a social community for its employees, including schools, a library, a social club, tennis courts, playing fields, a swimming pool, a well-stocked store and housing. According to Charlotte Mahaffy’s book, “I Remember Treadwell,” the only amenities not offered were bars, churches and fraternal organizations, all of which were available in nearby Douglas.

Treadwell’s history dates back to December 1880 when a group of prospectors sailed along Gastineau Channel and headed for Harrisburg (later renamed Juneau). The group stopped for the night on Douglas Island, three miles shy of Harrisburg. One of the prospectors panned a significant showing of gold from a nearby creek, and the group settled in to mine the creek placers. They named the stream Ready Bullion Creek.

A few months later, they discovered the lode source of the gold. Other prospectors began working Douglas Island, and in May, the Parris lode claim (the progenitor claim for the Treadwell mine) was staked.

In August of that year, John Treadwell, representing a group of San Francisco investors, bought the Parris claim. The next spring, he brought in a five-stamp ore-crushing mill, and, after extensive testing of the ore-body, the Parris Mine, later called the Treadwell, began operating.

The mine was successful. In 1889, it was sold to English investors for a reported $4 million, with Treadwell receiving $1.4 million for his share (after which he returned to California).

Over time, three adjacent mines were added to the operation: the Mexican, the Ready Bullion and the 700-Foot (so named because the claim, wedged in between the Mexican and Treadwell, was only 700-feet wide).

All four mines sank shafts to well-below sea level, with the deepest shaft, at the 700-Foot Mine, reaching 2,000 feet below sea level. And all the mines were linked via below-sea-level tunnels.

The mines had experienced ground instabilities as early as 1909 when a series of played-out stopes (the galleries from which ore was excavated) and supporting pillars in the Treadwell collapsed. In 1916, ground at the Treadwell began subsiding.

In April of 1917, ground subsidence in the vicinity of the Treadwell swimming pool, coupled with an extremely high tide, led to a catastrophic collapse and flooding of the Treadwell, 700-Foot and Mexican mines. Ironically, the Ready Bullion was the only mine spared — because a concrete plug had been installed in the tunnel between the Ready Bullion and Mexican Mine to prevent the other mines from flooding if the Ready Bullion experienced a cave in.

The Ready Bullion continued to operate until 1922. Numerous plans were floated to re-open the flooded mines or bypass the flooded levels, but none came to fruition.

The death knell for the Treadwell Complex came in 1926 when a fire destroyed most the wood frame buildings at Treadwell as well as much of Douglas.

Douglas recovered, but Treadwell did not. Now, only a few concrete structures — such as the saltwater pump house shown in the drawing, scattered concrete foundations, and bits of machinery and pipe — remain.

The Treadwell property is owned by the City and Borough of Juneau. The nonprofit Treadwell Historic Preservation and Restoration Society takes care of the property through a cooperative agreement with the municipality, and it has produced a development and interpretive plan for the site. The society has already stabilized and partially rehabilitated two buildings, installed interpretive signs and provided trail maintenance. The site is open to the public.

Sources:

• “‘History comes alive’: Treadwell preservation vision looks to balance education, recreation.” Alex McCarthy. In Juneau Empire. 10-30-2018
• “I Remember Treadwell.” Charlotte L. Mahaffy. Accra Print. 1983
• “New-look mining building gets a ribbon cutting.” No author listed. In Juneau Empire. 9-18-2019
• “The Juneau Gold Belt: a History of the Mines and Miners.” Earl Redman. Publication Consultants. 1988
• “Treadwell Gold, An Alaska Saga of Riches and Ruin.” Sheila Kelly. University of Alaska Press. 2010
• “Treadwell Mine Historic Site and Trail Plan.” Deborah Mattson. Corvus Design. 2018