A review of Interior Department land-use records by the Environmental Working Group showed that there is considerably more acreage under lease for oil and gas development than there is for hard-rock mining in the Three Rivers Withdrawal, signed by Norton on Sept. 11.

Within five miles of the river, there are eight times as many acres under lease for oil and gas development than for mining, the group found.

“The Norton announcement thus protects the land from the wrong environmental threat entirely,” the study stated.

The order that Norton signed prohibited hard-rock mining on 200 miles along the banks of the Colorado, Green and Dolores rivers in southeastern Utah. But the secretary's directive did not affect 103 existing hard-rock mining claims on 3,300 acres of the river canyons. Nor does it affect 11 oil and gas leases on 5,776 acres of the river corridor.

Three days before Norton signed the withdrawal, the Bureau of Land Management auctioned off oil and gas leases on roughly 5,000 acres in the area surrounding the rivers.

Calls to the Interior Department seeking comment were not immediately returned Thursday.

The Three Rivers decision allows drilling as little as 1,300 feet from the rivers, and the Environmental Working Group says it does not consider noise pollution and water quality threats.

Norton signed the Three Rivers Withdrawal nearly 18 months after it was submitted to the department for her signature. Conservationists questioned if the timing was an effort to help downplay anti-environmental policies of the Bush administration.