The Boulder Batholith and the Richest Hill on Earth

The ore this panel explains left a lake that has to be held in place. Once the pumps stopped in 1982 the Berkeley Pit rose six to seven feet a year toward 5,410 feet, the level regulators set as the point where pit water could reach Butte's groundwater. On September 30, 2019, under a consent decree, Atlantic Richfield and Montana Resources began treating pit and mine water and releasing it into Silver Bow Creek, the first discharge from the site. The rise stopped short of the line, and the pumping must continue as long as the pit remains.

Where it stands

Worth the stop nearby

• Mai Wah Museum — 3.2 mi
  Two brick buildings left from Butte's Chinatown, and a store whose goods came home after seventy years away.
• Granite Mountain/Speculator Mine Memorial — 3.4 mi
  An overlook above the shaft where the 1917 fire began, and the letters some of the trapped men wrote while they waited.

More markers nearby

• Butte — steps away
• Meaderville — steps away
• The Great Divide Trophy — 9.3 mi
• Keep Watching The Skies! — 15 mi