What Happened Here?
The environmental challenges facing Butte, Anaconda, Silver Bow Creek, and the upper Clark Fork River did not happen overnight. They are the result of more than a century of mining, ore processing, and smelting — much of it occurring long before environmental laws existed.
Understanding what happened here helps explain why cleanup is necessary, why it is complex, and why it continues today.
Early Mining and Silver Bow Creek
Mining in the Butte area began in the mid-1800s, following gold discoveries along Silver Bow Creek and its tributaries. Early miners worked placer deposits and shallow lodes, often directly adjacent to streams.
As mining expanded, waste rock, tailings, and process water were commonly discharged into nearby drainages. At the time, this was standard practice across the American West. There were few regulations, and little understanding of long-term environmental or health consequences.
Silver Bow Creek became the natural pathway for these wastes, carrying contaminated sediments downstream.
Learn more about Silver Bow Creek →
The Rise of Copper and "The Richest Hill on Earth"
In 1876, a rich copper vein was discovered at the Parrott Lode. That discovery transformed Butte from a modest mining camp into one of the most important industrial centers in the world.
Over the next decades:
- copper mining expanded rapidly
- mills and smelters were constructed
- railroads and infrastructure followed
By the early 20th century, Butte earned the nickname "The Richest Hill on Earth."
Underground mining extended deeper and farther, eventually creating more than 10,000 miles of underground tunnels and workings beneath the city and surrounding hillsides.
Mining brought jobs, population growth, and wealth. It also generated enormous volumes of waste rock, tailings, and contaminated water.
A City Built Above the Mines
Unlike many mining districts, Butte did not sit beside the mines — it grew directly above them.
Homes, schools, businesses, and neighborhoods were built amid headframes, waste rock dumps, and mine shafts. Families raised children in close proximity to mining activity that had been ongoing for generations.
At the time, the risks associated with metals like lead and arsenic were not fully understood. Contamination accumulated slowly, often unnoticed.
Residential impacts and cleanup →
The Berkeley Pit and a Shift in Mining
By the mid-20th century, much of the easily accessible underground ore had been extracted. Mining operations began shifting from underground methods to large-scale open-pit mining.
In 1957, work began on what would become the Berkeley Pit — a massive open pit visible today from across the region.
As open-pit mining expanded, underground operations were gradually abandoned.
When mining ceased in the early 1980s, the pumps that had kept groundwater out of the underground workings and pit were turned off. Groundwater began filling both the pit and the underground tunnels, reacting with sulfide minerals and creating highly acidic, metal-laden water.
How pit flooding is managed today →
The 1908 Flood and Downstream Impacts
In June of 1908, a combination of heavy rain, warm temperatures, and late snowmelt triggered a massive flood in the Silver Bow Creek drainage.
The floodwaters:
- spread over wide areas
- scoured mine tailings and smelter waste
- carried contaminated sediments far downstream
By the time the flood reached the Clark Fork River near Milltown, contaminated deposits were measured in feet, not inches.
This event spread mining-related contamination well beyond Butte, ultimately affecting areas as far downstream as Missoula.
Smelting, Anaconda, and the Broader Footprint
Mining was only part of the story.
Much of the ore extracted in Butte was transported to smelters in Anaconda, where copper was processed. Smelting generated additional wastes, including slag and airborne contaminants, which affected soils and ecosystems around Anaconda and beyond.
Together, mining and smelting created a regional contamination footprint that extended across watersheds and communities.
From Industrial Legacy to Superfund
By the late 20th century, it had become clear that the environmental impacts of historic mining were extensive and persistent.
Silver Bow Creek was designated a Superfund site in 1983. The surrounding Butte region was added in 1987. Over time, related sites in Anaconda and along the upper Clark Fork River were also addressed under the Superfund program.
Superfund did not cause these problems — it exists because of them.
The goal is not to erase history, but to protect people, restore ecosystems where possible, and ensure that contamination is managed safely for the long term.
What Superfund is — and is not →
Mining Today in Butte
Mining continues in Butte today, but in a regulated, limited form that operates separately from the Superfund cleanup. Modern operations follow environmental standards that did not exist during the historic mining era.