BOISE - Phosphate-mining companies want the Legislature to forbid Idaho regulators from forcing them to restore mineral-tainted groundwater beneath their operations to natural conditions once they shutter their mines -- because they say that standard is impossible to meet.

This legislation comes after negotiations at the Idaho Department of Environmental Quality broke down in 2007 amid differences between the industry and environmental groups.

Mining companies such as J.R. Simplot and Monsanto disagreed with draft rules requiring them to clean up groundwater beneath closed mines within eight years.

Meanwhile, environmental groups say mining companies are just trying to get out of requirements that they clean up damage to groundwater beneath open-pit mines in eastern Idaho that dot the Caribou-Targhee National Forest.