The approach presented in Golder’s HMP-AMP Supplement would not be effective in detecting impacts to groundwater levels, slope stability, or erosion. OHA implored Ecology to provide oversight when faced with poorly planned monitoring proposals, so that environmental damage does not result and to avoid the illusion that useful monitoring is being performed.
OHA explained that adequate monitoring is critical, including baseline monitoring, to ensure that changing conditions are detected early and operational adjustments are made, if needed, to protect the environment. Unfortunately, the HMP-AMP Supplement Plan lacks the detail required to ensure this would occur. Two of the main outfalls for the Buckhorn Mine had significant failures due to excessive discharges. The Supplement Plan should specify that if groundwater levels reach threshold levels, discharges should be reduced or cease.
Currently, there is no permitted discharge of treated mine water in the Bolster Creek drainage or on the west side of Buckhorn Mountain. While the new NPDES permit changes contaminant limits in surface and groundwater outside the mine to reflect background levels (conditions that existed prior to mining), the mine is allowed to discharge treated water at a higher water quality effluent limits for nitrate. These levels could degrade water quality in surface water, including at SW-14, and groundwater at MW-18 on the west side of the mine. The permit modification should include changing the Mine Water Treatment Plant effluent limit for nitrate to the groundwater limit outside the capture zone, which is 1.33 mg/l nitrate+nitrite as N.
While OHA supports the use of adaptive management, Crown has failed to implement adaptive management to adequately analyze the effectiveness of its actions, or to adapt its actions in light of new information. In fact, this failure has and continues to result in damage to the environment. Unpermitted discharge from mine facilities continues to contaminate ground and surface water outside the capture zone. Ecology should take a conservative approach when considering potential impacts. In the case of Outfall 006, such an approach would include: (i) evaluating the effects of maximum outfall discharge on downgradient waters and slope stability, and (ii) defining baseline and operational monitoring locations and frequency in a manner that is protective of the environment. These actions should occur before the outfall is approved.
NPDES Permit Modification Compliance Limits: Issues
OHA also expressed concern that some specific monitoring compliance locations may have NPDES limits that exceed baseline water quality values. We recommended that modifications be made to the NPDES permit so that NPDES compliance criteria more accurately reflect background water quality conditions in specific monitoring locations for specific constituents. OHA recommended that Ecology address these issues in a republished modification of the NPDES permit, since this would constitute a major change from the January 22, 2014 draft modification. Ecology published a second draft permit modification on March 5, 2015, which includes NPDES compliance criteria in specific monitoring locations for specific constituents that more accurately reflect background water quality.