River Mining

Mining the precious habitat native salmon, steelhead and cutthroat trout need to successfully reproduce

When gold is found in stream beds, it's because it's washed there from the surrounding land. Because gold is heavy it tends to settle in low gradient stream reaches. This is where in-stream gold mining operations are often concentrated.

Impacts of instream dredge mining on otherwise pristine low gradient salmon and steelhead spawning habitat.

However, these same low gradient reaches are usually the most biologically productive within a stream system. They're limited in number and area and are where the bulk of salmon and steelhead spawning takes place. The low gradient reaches of a stream are also the most sensitive and easily impacted.

We need to be protection and preserving fresh water habitat not mining it

Fragile yolk-sac fry.

Miners are using various sizes gasoline powered motorized suction dredges (essentially large vacuums) to mine the bed and banks of rivers and creeks for gold. They're subject to few regulations but chafe at those. On National Forest and BLM land miner's are not even required to notify the managing agency unless the believe their mining actives might cause harm.

One of the restrictions imposed is the instream work period. Miners and agency officials claim that in-water work periods address concerns that salmon and steelhead eggs, developing embryos and tiny hatchling fish could still be in streambed gravels. This is a simplistic view and can be argued, because when a fishes eggs are in the gravel and emergence is dependent on water temperatures and many other variables.

Salmon hen digging a redd (nest) with her tail, while the male hangs around ready to fertilize the nest. 

Anatomy of a redd

A redd is the nest native fish construct (to exacting specifications) usually in low gradient stream reaches. The diagram below of a redd show that the stream bed gravels have been sorted in layers and size. This occurs over seasons of high flows.

The natural sorting of gravels results in streambed stability. The reproductive success of the salmon or steelhead depends on this stability and other natural nuances of a spawning area. These include the right amount of flow through the gravels to provide adequate oxygen but not so much that the nest is destroyed and eggs and tiny hatchlings are crushed or set adrift to become food for someone else,

Suction dredge mining destroys the the stability and exacting conditions required for successful reproduction to occur.. If the gravels of the redds are unstable and move during high flows, the tiny eggs or hatchlings that are in the gravel will be washed out from the protection of the nest and destroyed.

Bulldozing the nursery

Even if true, that the tiny hatchlings are out of the gravel, the miners and agency logic still fails. Would it be ok to bulldoze incubators and nurseries in a hospital maternity wing when there are no babies present? No.

And while it’s less likely that salmon eggs and yolk-sac fry will be in the gravel during the in-water work periods, the tiny juvenile fish still inhabit these areas, where their ability to grow, gain strength and escape predators is critical in their struggle to survive and reproduce—and they’re not the only inhabitants of the biologically important streambed. Read more about science and impacts of suction dredge mining.

Stream ecosystems are more complex than we think

Life cycle of native naturally reproducing anadromous fish,

In the 1990s a famous forest ecologist told the President of the United States that:

“Not only are forest ecosystems more complex than we think; they are more complex than we can think."

He was paraphrasing pioneering plant ecologist Frank Egler, who assisted Rachel Carson with her seminal book, “Silent Spring.”

Stream ecosystems are no less complex than forest ecosystems. Yet streambeds—where life itself begins for the wild salmon and trout we prize—are treated as if they’re little more than assortments of rock by miners—and unfortunately by many land and resource managers.

Definitive studies

Salmon egg and tiny hatchling.

Miners often claim their instream mining is good for fish and that there's no definitive studies showing impacts to salmon from suction dredge mining. Yes well, there were no definitive studies showing that the Deepwater Horizon oil rig in the Gulf of Mexico would explode and look where that got us.

Most prominent scientists in the fields of fisheries and stream ecology believe there are impacts and peer reviewed studies published in scientific journals raise serious doubts about the practice.

Read "Effects of Suction Dredging on Streams" in Fisheries, the journal of the American Fisheries Society.

Is mining the highest and best use of our streams and river?

Chetco River steelhead caught and released.

There are stresses on our rivers and the priceless wild salmon and trout that inhabit them we can do little to control.  In-stream mining is not one of them. Both Federal and State agencies have the authority to regulate mining.

 It’s being done in neighboring Idaho. It's being done in California. And the land managing agencies have the authority to require miners to demonstrate they have an actual right to mine under the Mining Law.   However, right now in Oregon mining is treated as the highest and best use of our streams and rivers, even congressionally protected National Wild and Scenic Rivers.


See also The Science post.