The anatomy of the thousands of miles of tunnels beneath the Butte Hill is daunting to consider and little understood by many. Important details, such as the distinction between the “West Camp” and “East Camp”, can cause consternation for many a curious observer.
The Berkeley Pit and surrounding underground mine workings and bedrock wells are referred to as the “East Camp”, and are separate from the “West Camp”, which is located more to the south and west. The Camps essentially refer to two water systems. In the East Camp, surface and underground water flows to the lowest point in the system, namely, the Berkeley Pit. The West Camp, whose waters never reach the Berkeley, is another story.
The West Camp lies southwest of the Berkeley Pit/East Camp drainage and includes the Travona, Emma, and Ophir mine workings. Just as in the East Camp, the groundwater in this area has been closely monitored since the suspension of pumping in 1982 to ensure that water levels do not rise high enough to significantly impact surrounding aquifers—in this case, 5,435 feet is the magic number.
Since November 1989, pumping operations have kept West Camp water below this level. In the late 1950s, the West Camp mine workings were sealed off from the rest of the shafts and drifts on the Butte Hill by a series of barriers, or bulkheads—some made of wood, some cement.
Three main cement bulkheads block the connections between the Emma in the West Camp and the Original mine in the East Camp at the 1,600-foot level, and between the Emma and Colorado mines at the 1,400- and 1,000-foot levels.
Anaconda Company crews originally installed the bulkheads for two main reasons: 1) there were no plans to continue mining in the West Camp, and 2) they wanted to increase the efficiency of continuing mining operations in the other underground mines of the East Camp and the Berkeley Pit.
The bulkheads allowed the company to eventually reduce the volume of both groundwater pumped out from underground shafts and the area underground that required fresh air to be pumped in. However, even after the bulkheads were installed, water was pumped out of the West Camp Emma shaft until 1965.