The fire service worked through the night to assist with the pumping of toxic water from a disused mine near Truro.
Pumps are currently at full capacity at Wheal Jane. Levels are still rising, but at a slower rate than yesterday.
There are fears that rising levels could pollute the nearby river and Fal Estuary, a marine special area of conservation, although there has been no pollution so far.
More top news
A man who disguised himself in a chilling clown mask while committing armed robberies at Beefeater restaurants in Devon has been jailed.
Jazzie Watson was sentenced to at least 11 years in jail for stabbing his half brother Shamus McNama to death after an argument.
A huge fire which broke out at the start of the month and could be seen from across Cornwall is not being treated as suspicious.