BOISE, Idaho — The state Land Board has unanimously agreed to renew a lease and permit for a Grangeville company that mines gravel for a two-week period each winter from the bed of the Salmon River.

The decision by the board Tuesday gives Kaschmitter Enterprises Inc. permission to remove gravel for the next five years from a dry area of the riverbed downstream of Riggins.

The lease and permit were first issued by the state in 1955 and renewed periodically every five years.

But this time, environmentalists, anglers and rafting outfitters urged the board to delay approval and require more study of the operation and its impact on the river, fish and recreation.

Jonathan Oppenheimer, of the Idaho Conservation League, told the board Tuesday that too few studies have been done to gauge the effect gravel mining has had over the decades on water quality and downstream spawning beds for threatened salmon species. He also suggested that operating a gravel mine in the middle of the Salmon River sends the wrong signal about the state's commitment to protecting resources.

"The Salmon River is one of Idaho's most beloved treasures, and we ask you to protect the river in keeping with its iconic status," Oppenheimer told the board.

The Idaho Department of State Land recommended renewing the lease and stream channel alteration permit.

Eric Wilson, mineral programs manager for the agency, said there was no data submitted during the public comment period showing the operation has had a negative impact on the streambed or recreational values. He said gravel mining occurs during the winter months, long after the summer floating and fishing season. High flows from spring runoff typically deposit new gravel in the location where the mining occurs.

Tim Kaschmitter, owner of the mining company, said his crew is careful each season to avoid causing damage to the riverbed, water quality and vegetation along access points.

"We only spend a couple of weeks physically pulling the material out from below the high water mark," Kaschmitter said. "We pretty much limit our access to a just couple of different points to limit impact on vegetation."

The board includes Gov. C.L. "Butch" Otter, Attorney General Lawrence Wasden, Secretary of State Ben Ysursa, Superintendent of Public Schools Tom Luna and State Controller Donna Jones.