The National Environmental Policy Act requires the Forest Service to consider a reasonable range of alternatives that can accomplish the purpose of and need for the proposed action. The Forest Service studied a range of alternatives to the Resolution Copper general plan of operations. Snapshots summarize five action alternatives (out of 30+ considered) at four separate locations, including one location not on Federal land. Note that the Forest Service has identified Alternative 6 (Skunk Camp) – North Option as the Lead Agency’s preferred alternative.
Snapshots - Updated December 2019
A variation of the proposed action described in the May 9, 2016, version of Resolution Copper’s General Plan of Operations, this alternative would include a split-stream tailings processing method with two tailings types.
Shares several similarities with Alternative 2; one key difference is it proposes to reduce the amount of water retained in non-potentially acid generating (NPAG) tailings as well as reduce seepage potential through on-site thickening of NPAG tailings and ‘Thin-lift’ deposition.
The only alternative proposing to use filtered tailings instead of slurry tailings. Conveyors and mobile equipment would mechanically deposit potentially acid generating tailings and non-potentially acid generating tailings in two separate, adjacent tailings storage facilities.
This alternative allows for a comparison of the impacts of slurry tailings if placed in a flatter, alluvial setting instead of an upland wash or canyon.
The location for this alternative would enable use of cross-valley embankments/dams requiring less fill to retain tailings compared to a ring-like impoundment, simplifying construction and operations.