The underwater gold rush

The right to dredge part of Idaho’s Salmon River for garnets and gold now belongs exclusively to one man.

That was the decision of the Idaho Land Board last week when it granted Mike Conklin a mineral lease for a half-a-mile stretch of the river below Riggins, a small town near the western border of the state. Conklin plans to scour the riverbed for treasures using a process called suction dredging, a controversial mining practice that has been banned in California because of its negative impacts to water quality and fish habitat.

Conklin isn’t the only prospector in Idaho sucking up a riverbed in pursuit of gold—permits to suction dredge are $10 and the state's department of water resources has issued 700 permits this year. Conklin is, however, the first dredger to lease the mineral rights to a section of river, giving him exclusive access to mine that area. Unlike a permit (which can be purchased much like a fishing license), a mineral lease requires approval by the Idaho Land Board, so Conklin’s request thrust suction dredging into the public eye.

Suction dredging is gaining in popularity as the price of gold has leapt upwards of $1,700 per ounce. Here’s how it works: a powerful under-water vacuum is mounted on a raft, and a scuba diver swims along the bottom of a river with a hose, sucking sediment and gravel into the vacuum. The vacuum separates gold, which is heavier than gravel and other metals, and spits the other materials back into the stream. Suction dredges are popular because they work in deeper rivers and suck up a large volume of the streambed, recovering gold that in the past would have been difficult to find.

Few miners expect large profits from the practice, but enthusiasts say it’s a fun way to spend a weekend in the outdoors and make enough money to pay for gas. Some proponents say the practice actually improves water quality by removing mercury and lead from fishing weights from the streambed.

But many environmentalists disagree with that claim and say the dredges release buried mercury into the water and increase turbidity, coating salmon eggs in silt or inadvertently sucking them up (see “Hobby miners flock to public streams,” HCN 5/1/06). The negative effects of suction dredging on fish are well-documented in peer-reviewed research, and contributed to California’s decision in 2009 to put a moratorium on the process (see “Sucking up gold,” HCN 4/27/11). A rider on this year’s budget extended that moratorium indefinitely, unless the state finds a way to address suction dredging’s environmental impacts.

Just over the border in Oregon, however, suction dredging is allowed as long as miners get a permit and keep a record of their activity. There are restrictions on how much silt miners can churn up, but little enforcement of those rules.

Technically, all suction dredging without a discharge permit is illegal, but the EPA doesn’t enforce the law—yet. The agency is developing a general permit for suction dredge mining in Idaho that it hopes to roll out at the end of this year. Tracy DeGering, an environmental scientist with the EPA, told Earthfix that it’s likely a majority of Idaho Rivers would be closed to mining once the agency issues a general permit.

In the mean time, suction dredge mining continues in Idaho’s rivers and streams, much to the chagrin of Jonathan Oppenheimer, a senior conservation associate with Idaho Conservation League.

“As of right now, there’s no monitoring, no enforcement, there’s rampant violations of state laws (and) federal laws,” he said. “It is the Wild West when it comes to recreational suction dredge mining in Idaho’s rivers and streams.”

Emily Guerin is an intern at High Country News.

Photo of suction dredge on California's Klamath River courtesy Klamath Riverkeeper