Small-scale mining, also known as recreational mining, refers to a variety of types of mining operations ranging from gold panning as a weekend hobby, using a sluice box, or operating a suction dredge to mine for gold at the bottom of a streambed.
Suction dredging is a relatively new mining method that uses a suction dredge machine – similar to a large underwater vacuum cleaner – to suck material up from a river or stream bottom. The machine runs the material through a separation system to recover the valuable materials, and then jettisons the sediment and gravels back into the water as tailings or spoils.
Gold panning or the use of sluice boxes most often has a negligible effect on the surrounding land, water and wildlife. Suction dredging, on the other hand, can damage streams and impair fish and other aquatic life.
Aquatic Ecosystem Impacts
Suction dredge operations can harm important fisheries by destroying fish eggs, degrading spawning sites, and harming the aquatic insects that fish eat.
Salmon and other fish use the bottom of streams to lay their eggs. Salmon bury their eggs in gravel nests at the bottom of a stream. Other fish, like whitefish, spawn in the stream and their eggs settle to the streambed where they remain on the gravel surface throughout the incubation period.
A suction dredge pump vacuums water and gravel through the nozzle and hose at 9 to 10 feet per second. Fish eggs taken up with the gravel cannot survive the battering and pounding that comes with moving through the hose. Spawning success may also be affected if the fish lays its eggs on unstable dredge tailings. Stability is critical to spawning success of many fall-spawning species.
Further impacts to fish may occur when the silt and gravel that runs through a suction dredge flows downstream and settles among the gravel and rocks in the streambed. Too much silt and sand make it difficult for the salmon to dig suitable nests to spawn and can smother fish eggs already deposited on the bottom of the stream. Aquatic insects, which fish eat, also have difficulty living in heavily silted streams.
Recreational Mining and the Law
Under current law, small mining operations are exempt from the $155 claim maintenance fee. This waiver applies to anyone that holds 10 or fewer claims. In order to receive the fee waiver, annual assessment work must be performed on the claims.