## Facts

- Coeur Alaska, Inc. sought to reopen the Kensington gold mine near Juneau, Alaska, using froth-flotation to separate gold from ore.
- The process generated a slurry of water and finely ground rock, along with processing reagents, proposed to be discharged into Lower Slate Lake in the Tongass National Forest.
- The discharge would deposit approximately 4.5 million tons of tailings and substantially raise the lakebed, with clarified water later released from the lake to a downstream creek.
- The Clean Water Act authorizes permits for discharges into waters through two programs: §404 permits issued by the Army Corps of Engineers for “fill material,” and §402 permits issued by EPA (or authorized states) for other pollutant discharges subject to effluent limitations.
- In 2002, EPA and the Corps adopted a joint regulatory definition of “discharge of fill material” that included “tailings or similar mining-related materials.”
- In 2005, the Corps issued Coeur a §404 permit authorizing the tailings discharge into Lower Slate Lake.
- Environmental organizations challenged the permit, contending the discharge was process wastewater governed by EPA’s §402 program and prohibited by EPA’s §306 new source performance standards for froth-flotation gold mines.
- The district court upheld the permit; the Ninth Circuit reversed and ordered the permit invalidated; the Supreme Court granted review.

## Issues

1. Whether the proposed discharge of mine tailings into Lower Slate Lake was “fill material” regulated under the Corps’ §404 permitting authority or a discharge subject to EPA’s §402 program and effluent limitations.
2. Whether EPA’s §306 new source performance standards for froth-flotation gold mines independently barred the Corps from issuing a §404 permit for the discharge.

## Decision

- The Supreme Court reversed the Ninth Circuit and remanded.
- The Court held the discharge qualified as “fill material” under the agencies’ joint regulatory definition and therefore fell within the §404 permit program administered by the Corps.
- The Court held the Corps’ issuance of a §404 permit did not violate EPA’s §306 performance standards, which the agencies reasonably treated as applicable within the §402 permitting context rather than as an independent bar to §404 permitting.
- Justice Breyer concurred, emphasizing EPA’s ability to revise regulations if the allocation of authority created unacceptable results.
- Justice Ginsburg dissented (joined by Justices Stevens and Souter), reasoning that the discharge should be regulated under §402 and constrained by §306 standards.

## Legal Principles

- When a discharge meets the jointly promulgated regulatory definition of “fill material,” permitting authority lies with the Army Corps of Engineers under CWA §404 rather than with EPA under §402.
- EPA’s §306 new source performance standards for covered industrial categories do not, by themselves, negate a §404 permit for material properly classified as “fill” under the agencies’ regulations.
- Courts generally defer to EPA and the Corps’ reasonable, consistent interpretation allocating authority between the CWA’s §404 and §402 permitting programs where the statute does not clearly resolve overlap.

## Conclusion

The Court upheld the Corps’ authority to permit disposal of mine tailings into a lake under §404 as “fill material,” and accepted the agencies’ interpretation that EPA’s §306 performance standards did not independently bar that §404 permit.


Coeur Alaska, Inc. v. Se. Alaska Conservation Council, 557 U.S. 261 (2009)