Workers early Saturday morning contained a chemical spill at the Kennecott Eagle Mine.
No one was injured after a faulty valve caused a chemical to spill in the water treatment plant.
The mine's water treatment plant stores the chemicals which are used in the treatment process.
The chemical was fully contained within a sealed area, according to Rio Tinto.
"Our team responded promptly, and our environmental safeguards worked properly to protect the environment," said Eagle Mine president Adam Burley.
The company says there is no risk to the environment.