DENVER -- Drilling will begin next week to relieve water pressure from behind an old mining tunnel near Leadville.

Final plans are under way for a pipeline that will transfer 1 billion gallons of contaminated water to a filtration plant. The water will ultimately be released into the Arkansas River.

Congress, in the meantime, is taking a closer look at legislation that would force the Bureau of Reclamation to accept responsibility for the site and commit to its cleanup.

The price tag could reach $40 million.

"We think the time for studies has passed. We know what we have to do and we are intending to move forward with our legislation and see it become law," said Rep. Mark Udall.