BOISE, Idaho - Monsanto Co., Agrium Inc., and J.R. Simplot Co. will be able to mine phosphate without being forced to restore groundwater beneath their operations to its natural condition, according to a new rule awaiting approval by the 2009 Legislature.

The rule is backed by industry but opposed by environmentalists including the Greater Yellowstone Coalition and Idaho Conservation League, who say it gives mining companies near the Idaho-Wyoming border license to pollute forever.

It stops short of a 2007 draft proposal developed by the Idaho Department of Environmental Quality but never formalized. That would have required companies to clean up groundwater below their mines within eight years of ceasing activities.

According to the new rule, mining companies could pollute groundwater below their extraction, reclamation and tailing activities with high concentrations of naturally occurring elements such as selenium. They would be required to monitor groundwater at so-called "points of compliance" as close as possible to the mining area, to make sure the pollution stayed put.

Jack Lyman, a lobbyist with the Idaho Mining Association, said the new rule would protect groundwater outside mining areas without saddling companies aiming to build new mines or expand existing ones with onerous, unrealistic cleanup mandates.

"We have never asked for the right to mess up someone else's beneficial use of the groundwater," Lyman told The Associated Press on Tuesday. "The department came up with a rule they think is workable, without putting our industry into a difficult situation where we'd be unable to comply."

Efforts to revise Idaho's 16-year-old Groundwater Quality Plan began in 2007 after the Department of Environmental Quality, the mining industry and environmentalists agreed the exemption allowing mines to pollute groundwater in some instances was ambiguous. Mining companies feared uncertainty over cleanup requirements could stifle new projects; environmentalists said vagueness made it easier for companies to pollute.

After more than a year of wrangling, the proposed rule was approved by the Department of Environmental Quality Board earlier this year. It will be taken up by the 2009 Legislature when the session starts Jan. 12. Such rules are rarely rejected, especially after securing board support.

Justin Hayes, with the Idaho Conservation League, contends the state agency "caved in" to industry pressure. Environmental groups are fearful of mining pollution in eastern Idaho, especially after at least four horses and hundreds of sheep died in the late 1990s after drinking selenium-contaminated water from defunct phosphate mines and their waste piles near Soda Springs.

"By its very nature, groundwater doesn't stay in one place," Hayes said. "An aquifer is recharged by rain and snow water, then it moves somewhere else. Aquifers are in motion. Eventually, the contamination is going to move off site."

Jess Byrne, a spokesman for the state agency, didn't immediately return a phone call seeking comment.

Lyman insists environmentalists are exaggerating the danger that mining pollution will migrate. He drew a comparison between the septic tank at his home near Caldwell and open-pit phosphate mines.

"I've never worried about anything I put in my sink showing up a quarter of a mile away on my neighbor's property," Lyman said, adding that just because groundwater below a mine is polluted "does not mean that's going to flow down into Soda Springs, Idaho."