Associated Press - November 20, 2009 6:24 PM ET

BOISE, Idaho (AP) - Monsanto Co. is installing a water management system at its southeastern Idaho phosphate mine that's leaking selenium and heavy metals into a tributary of the Blackfoot River.

The company hopes capturing runoff and underground water from the waste rock dump below its South Rasmussen Ridge Mine will remedy leaks that have resulted in Clean Water Act violation notices from the federal Environmental Protection Agency.

Activist groups have demanded Monsanto remedy problems like South Rasmussen's dump before it gets federal approval for a new mine nearby.

The St. Louis-based company says this water management system would have been built regardless of its efforts to mine elsewhere in the region.

Dave Farnsworth, who heads Monsanto's phosphate mining operations in Soda Springs, says "Our engineers have extensively studied this issue, and believe this design will work."

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