About the New NPDES Permit

    During mining, the area that is being mined may become contaminated. The new permit slightly expands the farthest extent that contaminants are allowed to migrate – known as the capture zone – but it establishes points of compliance that must maintain background levels. OHA and our consultants provided extensive comments to Ecology concerning the proposed changes to the map of the capture zone for the mine. Ecology expanded the area that is allowed to be contaminated on most of the east side of the mine. The southeast portion was a hard fought concession the company received in the penalty settlement agreement, which Ecology justified because they had made an error in approving a dewatering well outside the capture zone in that area. Ecology reduced the size of this expansion from what was in the draft permit, so that additional monitoring could be put on Crown’s private land. OHA had hoped that Ecology would acknowledge the mistake and take actions to correct that error, instead of adding another mistake by incorporating the additional area into the capture zone, thereby increasing the area of contamination. Instead, the capture zone was made larger to account for this well’s influence in drawing contaminants away from the mine. OHA called for adequate compliance monitoring in the southeast portion of the mine, outside the capture zone, to ensure that the capture zone is maintained. 


Above: The near-surface expression of a fault (shown in bold brown above) is within the expanded capture zone, and is now allowed to be contaminated. The fault may carry water outside the capture zone and it may be difficult to control the movement of contaminants within the fault. However, the new permit requires that contaminants be controlled to maintain clean water outside the capture zone.

The northeast section was approved because the water quality “points of compliance” are still outside the capture zone area depicted on the map. OHA is concerned about the northeast section because there is a fault in this area that creates a preferential flow path in the mine vicinity, which already seems to feed contamination to areas outside the capture zone. The change puts the near surface expression of the fault inside the expanded capture zone; if it is allowed to be contaminated, it may be difficult to control contaminant movement within the fault, and therefore to maintain clean water outside the capture zone.

Although the mine has pumped massive amounts of groundwater from Buckhorn Mountain so they could mine, this has not been sufficient to keep mine contaminants from escaping into the environment. Now with the new permit issued, it should be universally understood that all mine contaminants must be captured and treated before they are discharged, and that no amount of inadvertent discharge from the mine is permitted.

The new permit contains separate compliance standards for surface and ground water, since background levels for each were different. This stands to reason since groundwater is usually in contact with mineralized rock for longer periods of time than is surface water, and concentrations of major elements and metals can be higher in groundwater as a result. Seeps and springs could have been added to either table, and Ecology chose to incorporate them with the groundwater data. OHA pushed for surface and groundwater to be given their own compliance standards, which reflect what the levels would naturally be, and we are glad to see this issue handled appropriately in the new permit.

In summary, the new permit increases environmental protection in some key areas while making other areas more vulnerable. Even though the surface expression of the capture zone was expanded, which increases the area that is allowed to be contaminated, the introduction of points of compliance for maintenance of the capture zone is a big improvement. The permit requirement that background water quality levels must be met is a major improvement. This requirement applies both to treated water and to water quality outside the capture zone, and will continue as long as treatment is necessary. Hopefully this will bring Buckhorn groundwater and streams back to the same levels found prior to mining. OHA applauds these changes and yet remains concerned that even with the generous interim limits, unless the company takes immediate and significant actions, the new standards will be difficult to achieve.

To read the remainder of the NPDES Overview, please see page 5 of the Fall 2013 Buckhorn Bulletin


(Left to right: Aerial of Buckhorn Mine; mine and waste rock; 2011 landslide in Gold Bowl Creek; culvert with sediment)