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Small-Scale Mineral Prospecting White Paper

Category: Habitat - Guidelines

Date Published: December 2006

Number of Pages: 164

Author(s): R2 Resource Consultants (for the Washington Department of Fish and Wildlife)


In Washington State, activities that use, divert, obstruct, or change the natural bed or flow of state waters require a Hydraulic Project Approval (HPA) from the Washington Department of Fish and Wildlife (WDFW) (Revised Code of Washington [RCW] 77.55). The purpose of the HPA program is to ensure that such activities do not damage public fish and shellfish resources and their habitats. To ensure that the activities conducted under the HPA authority comply with the ESA and to facilitate ESA compliance for citizens conducting work under an HPA, WDFW is preparing a programmatic, multispecies Habitat Conservation Plan (HCP) to obtain an Incidental Take Permit (ITP) from the U.S. Fish and Wildlife Service (USFWS) and National Oceanic and Atmospheric Administration (NOAA) Fisheries Service (known as NOAA Fisheries or National Marine Fisheries Service). WDFW’s objective is to avoid, minimize, or compensate for the incidental take of species potentially covered under the HCP resulting from the implementation of permits issued under the HPA authority. In this context, to “take” means to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect or to attempt to engage in any such conduct (16 U.S.C. 1532(19)).

To evaluate the feasibility of and develop a scientific foundation for the possible HCP, WDFW has commissioned a series of white papers to review and summarize the best available science for up to 21 HPA activities that could be included in the HCP. This white paper addresses the availability of scientific information on one such HPA activity, small-scale mineral prospecting.

The literature review conducted for this white paper identified seven impact mechanisms associated with the operation of small-scale mineral prospecting activities that could potentially affect aquatic species being considered for coverage under the HCP (“potentially covered species”). These mechanisms describe activities and modifications to habitat arising from activities that can be temporary or permanent in duration. The impact mechanisms evaluated in this white paper are:

  • Excavation/entrainment
  • Wading
  • Substrate modifications/channel hydraulics
  • Water quality modifications
  • Channel dewatering/obstructions to passage
  • Prey base alterations
  • Human disturbance

Following a brief description of small-scale mineral prospecting activities and potential impact mechanisms, the 52 aquatic species being considered for coverage under the HCP are described. Based on this information, the risk of direct and indirect impacts to the potentially covered species or their habitats are discussed. In addition, the potential for cumulative impacts is discussed, and the risk for incidental take of potentially covered species is qualitatively estimated. The white paper then identifies data gaps (i.e., instances in which the data or literature are insufficient to allow conclusions on the risk of take). The white paper concludes by providing habitat protection, conservation, mitigation, and management strategies consisting of actions that could be taken to avoid or minimize the impacts of small-scale mineral prospecting. Key elements of the white paper are summarized below.

Activity Description

In 1997, the Washington State Legislature passed Substitute House Bill (SHB) 1565, which defined small-scale mining and prospecting and prohibited any requirement to obtain a written HPA before conducting small-scale mining and prospecting (WDFW 1999). The Gold and Fish Rules and Regulations for Mineral Prospecting and Placer Mining in Washington State (Gold and Fish pamphlet; WDFW 1999) serves as the HPA for mining and prospecting activities that comply with the guidelines of the pamphlet. However, small-scale mineral prospecting activities that do not meet all of the requirements of the Gold and Fish pamphlet can be authorized under other HPA types (e.g., individual HPA or supplemental approval).

Small-scale mineral prospecting and mining was defined as the use of pans, non-motorized sluice boxes, concentrators, and mini-rocker boxes to discover and recover minerals. SHB 1565 also refers to any mining activity that complies with the most current version of the Gold and Fish pamphlet, such as suction dredging. Small-scale mining is defined only by the type of equipment used, without reference to the volume of material sorted. Small-scale mining does not include chemical mining or dredge sizes greater than 4 inches.

Species and Habitat Use

This white paper considers potential impacts on 52 potentially covered species and summarizes the geographic distribution and habitat requirements of those species. That information was used to assess potential impacts on the potentially covered species.

Direct and Indirect Impacts

The available literature, including several specific small-scale mining studies, was reviewed to determine the current state of knowledge regarding direct and indirect impacts on the potentially covered species. Direct impacts can include: (1) mortality from the physical effects of wading or entrainment of early life history stages or eggs; and (2) lower productivity resulting from habitat modifications (e.g., altered streambeds or water quality). Indirect impacts can include changes in food resources and human disturbances.

The various studies documented several types of impacts related to the distance between mining activities, turbidity levels near and downstream of the mining activities, the use of unstable mine tailings by fish for spawning locations, changes in channel morphology, and alterations to prey resources related to suction dredging and sedimentation. This information provided a basis for comparison to current HPA and Gold and Fish pamphlet requirements for small-scale mineral prospecting.

The seven identified impact mechanisms associated with the operation of small-scale mineral prospecting activities that could affect potentially covered species are evaluated in this white paper. Each of the impact mechanisms is briefly described below.

Table ES-1
Principal Impact Mechanisms Evaluated

Impact Mechanism


Excavation/Entrainment All physical disruption of the streambed and removal of organisms from their natural environment. This mechanism includes organism displacement.
Wading Physical abrasion and crushing of organisms underfoot.
Substrate Modifications/Channel Hydraulics Changes in substrate composition (grain size) or morphology that result when channel processes are altered by artificial means (e.g., excavation or deposition). This mechanism includes stranding.
Water Quality Modifications Changes in water quality, primarily in turbidity but also in metallic and hydrocarbon toxins.
Channel Dewatering/Obstructions to Passage Changes that result from altered flow, principally dewatering that occurs due to stream diversion during mining activities; or stranding of organisms due to dewatering, excavation, or placement of spoils. Influence of equipment, dams, or diversion obstructions on migrating species.
Prey Base Alterations Changes to food sources that impact aquatic organisms by altering their prey base.
Human Disturbance The potential for human disturbances (e.g., noise) along the channel during mineral prospecting activities to indirectly displace or disrupt the behavior of potentially covered species.

Cumulative Impacts of Small-Scale Mineral Prospecting

Cumulative impacts can result from small-scale mining in the same location for multiple years or from multiple mining operations occurring within an area. The geographic concentration of the individual HPAs reviewed for this white paper (i.e., a review of a subset of those operations not conducted using the Gold and Fish pamphlet guidelines) demonstrates the potential for significant portions of creeks to be mined and therefore highlights the importance of understanding or recognizing the potential for cumulative impacts to potentially covered species and their habitats.

Data Gaps

The majority of literature focuses on fisheries, water quality, or non-covered species of aquatic invertebrates. Little information was found regarding the direct impacts of smallscale mining on some of the other potentially covered species, including mussels, snails, limpets, and non-salmonid fishes. Additional research is underway concerning the influence of small-scale mineral prospecting on freshwater mussel species, but the information was not available for this review. Additional research needs to enhance the evaluation of the potential for take via direct, indirect, and cumulative impacts of potentially covered species are presented.