DENVER — Hard rock mines would have to find the money up front to show they have the ability to assure that any water supplies are protected from contamination under a bill that won preliminary approval in the Colorado House on Wednesday.

The measure, HB1113, stems from issues with abandoned mines throughout the state that have led to contamination of Colorado's water supplies, not the least of which was the dramatic spill in the Animas River from the long-closed Gold King Mine in 2015.

While the measure doesn't address similarly abandoned mines, one of its sponsors said it is an attempt to prevent future mishaps with active mines.

"Up until now, people can self-bond," said Rep. Barbara McLachlan, D-Durango. "They can put the money down and promise that they will pay to clean up the water after their mining operations are finished. In many, many cases they go bankrupt before they can actually clean up the mine, and you the taxpayers are left with the bill of cleaning it up." 

Under current law, mining companies can submit audited financial statements to show they have the financial wherewithal to deal with any environmental issue from their operations, and can handle proper reclamation when those operations cease.

But several companies either have walked away without doing any reclamation or went out of business and had no way to pay for the cleanup. As a result, there are more than 23,000 abandoned mines in the state, according to the Colorado Geological Survey.

The bill, which requires a final House vote before heading to the Senate, would eliminate the audited statement and require new mining permits to include sufficient bonds to handle reclamation costs. Active mines that used audited statements to get their permits would have a year to establish a bond.

McLachlan, who introduced the bill with Rep. Dylan Roberts, D-Avon, pointed to the Summitville Mine in the San Luis Valley as an example. That closed gold mine became a Superfund site because of environmental damage in the 1980s from byproducts that leaked into the Alamosa River.

"Summitville is one we're going to be starting to pay $2.2 million," McLachlan said. "This company went in and they showed all the paperwork saying they had the money to clean this up, but by the time the mine was done, they went bankrupt and we the taxpayers have to pay."

Supporters of the measure say the Colorado Mining Association no longer opposes the bill, but some lawmakers still questioned it.

While Rep. Marc Catlin, R-Montrose, said the state should support more mining in Colorado, if for no other reason than to stop supporting questionable mining practices in other countries, Rep. Kimmi Lewis, R-Kim, said she opposes the measure because one mining company asked her to do so.

"That one independent business owner who owns that mine, I'm going to stand with them," she said. "And I'm going to remind you all ... how much we need those small independent business owners."

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