Opinion ID: 771609
Heading Depth: 3
Heading Rank: 1

Heading: Discussion of Mitigating Measures in this EIS

Text: 21 The EIS contains an extensive discussion of the potential effects of the Project on water quality, both in the mine-pit lake and in the ground water. The Forest Service conducted geochemical modeling by computer to predict (a) the quality of water that would accumulate in the pit and discharge from the lake and (b) the potential effects of the discharge. The EIS predicts that the [w]ater that would fill and ultimately discharge from the open pit is predicted to exceed the Washington fresh water chronic criteria for cadmium, copper, lead, mercury, and selenium and the Washington State fresh water acute criteria for silver and selenium. The EIS also concludes: In light of the relatively low flow and short ground water flow path predicted (the pit acts as a ground water sink, except for the extreme northeast corner), seepage from the open pit is expected to have a low overall impact on ground water quality in the vicinity of the pit. Furthermore, due to the biased assumptions used in the pit water quality study, predicted pit lake pollutant concentrations may overestimate the concentrations that would be observed under field conditions. 22 EIS 4.6.3 at 4-49. 23 The EIS discusses monitoring measures that would be required in order to quantify any measurable environmental impacts . . . . Impacts that result in violations of regulatory stipulations would require alterations of Crown Jewel Project operations or additional mitigation actions. Mitigation is discussed separately in section 2.12 of the EIS. The EIS uses a rating system to determine the probable effectiveness in achieving the mitigation measures objectives. Each mitigation measure is rated High (achieves the desired results more than 90 percent of the time), Moderate (achieves the desired results between 75 and 90 percent of the time, or logic dictates that it is more than 90% effective, but no documentation exists), or Low (effectiveness is unknown or unverified, or estimated to be less than 75 percent). The EIS proposes that potential water discharge problems be mitigated in the following manner: 24 Any water discharged from the Crown Jewel Project site, including the mine pit or collection and infiltration ponds, must meet [Washington] water quality permit requirements and federal water quality standards. If water quality requirements are not met, appropriate water treatment would be required. Water treatment may include, but is not limited to: 25 Precipitation and settling using lime, sulfide, ferric ion, and/or flocculents; Filtration; 26 Ion exchange; 27 Reverse osmosis; 28 Electrodialysis; 29 Air stripping; 30 Biological precipitation; or, 31 Passive wetlands. 32 Water quality problems may also be addressed by diverting discharges to the tailings facility (during operations only), or special cap design and construc tion on waste rock disposal areas or tailings pond embankments. 33 If water quality problems develop, then several steps would be taken to achieve compliance. These are: 34 1. Review of environmental impacts with the pos sibility of additional or increased frequency of monitoring; 35 2. Implement an interim (emergency or long term) water management plan to stabilize the situa tion; 36 3. Develop a conceptual engineering design of water treatment system alternatives that would be available to remedy the situation and select the most appropriate design for more detailed engineering; 37 4. The Proponent would prepare a detailed engi neering design of the selected alternative; the agencies would review and revise, as appropri ate, the environmental protection performance security required from the Proponent; 38 5. Undertake appropriate permitting of the selected water treatment system (conduct NEPA/SEPA review as appropriate); 39 6. Construct the selected water treatment system; 40 7. Operate and maintain the water treatment sys tem to meet design goals; 41 8. Monitor the water treatment system for compli ance; and, 9. Achieve a demonstrated `clean closure' or main tain long term (permanent) treatment. 42 Goal: Protect ground and surface water quality in case of unacceptable water discharges. Effectiveness: High 43 EIS 2.12.5.2 at 2-115. 44 The EIS's discussion of the mitigating measures required for the mine-pit lake takes a similar form. The EIS notes that the water in the mine-pit lake would be required to meet Washington State Aquatic Life Water Quality Standards and human health standards. The EIS then lists a nine-step process for BMG to follow in case the mine-pit's water quality exceeds the state criteria for protecting aquatic life or human health. For example, the EIS requires BMG to prepare a conceptual engineering design of water treatment system alternatives that would be available to remedy the situation as prescribed by modeling. The EIS notes that any water treatment system implemented by BMG would be subject to agency review and revision and, possibly, to further NEPA review. The EIS gives those mitigating measures an effectiveness rating of Moderate-High. 45 The EIS also contains a discussion of the possible environmental effects of, and the possible mitigating measures for, the waste-rock dumps. The EIS states that [h]umidity cell tests and confirmation geochemical testing indicated that 5% to 15% of the total waste rock material mined under[Alternative B] would potentially generate acid and leach metals. Potential effects include the leaching of dissolved metals,radionuclides, and nitrate into ground water and increases in sediment loading to streams. A more extensive analysis of the effects of the waste rock, based on computer modeling, is found in section 3.3.3 of the EIS at 3-10 to 3-21. The EIS states that, [i]f needed, an underdrain (french drain) system would be installed to intercept any spring and seep flow from the leaching of waste-rock material. During operations, all water draining from, or through, waste rock areas would be collected in sediment traps. Water collected in the ponds would be allowed to seep into the ground water system if quality is suitable. The EIS concludes that short-term impacts to ground water quality from the waste rock disposal areas are not expected to be substantial. Long-term impacts are expected to be somewhat less than during operations. 46 The EIS discusses, in a format like the one previously described, potential measures to mitigate the adverse effects of the waste-rock dumps: 47 The Proponent would be required to develop a waste rock management plan as part of Crown Jewel Proj ect permitting. This plan would address the potential for formation of acid generating hot spots and pre vention of acid rock drainage. The plan must be approved by the [Washington Department of Ecol ogy], [Washington Department of Natural Resources], BLM, and Forest Service prior to approval of the NPDES permit. The BLM and Forest Service would require this waste rock management plan prior to movement of waste rock as part of the Plans of Operations. 48 EIS 2.12.5 at 2-114. 49 The EIS explains that the waste-rock management plan must contain certain features, such as the procedures that would be used to handle, isolate, encapsulate and/or blend waste rock that exhibits acid generating potential.  Those measures are given an effectiveness rating of High.