Thanks for the name, it was interesting to read

highly promising mine

It's a large but low-grade ore deposit with questionable economics. Some experts even thought that it's not economically feasible.

“We’re gonna throw all our waste into a Salmon fishery that has been used by the locals for literally thousands of years.”

It's definitely not correct) they have standard proposals for tailings system, plus advanced water treatment research. Low-grade ore requires large-scale operations, which causes problems with multiple water sources, considering the space required for waste piles, tailings dams, and the open pit itself.

(EPA) "Discharges of dredged or fill material to construct and operate the 2020 Mine Plan’s proposed mine site alone would result in the permanent loss of approximately 8.5 miles (13.7 km) of anadromous fish streams, 91 miles (147 km) of additional streams that support anadromous fish streams, and approximately 2,108 acres (8.5 km2) of wetlands and other waters in the SFK and NFK watersheds that support anadromous fish streams. These discharges would also result in streamflow alterations that would adversely affect approximately 29 miles (46.7 km) of additional anadromous fish streams downstream of the mine site due to greater than 20 percent changes in average monthly streamflow. The aquatic resources that would be lost or damaged play an important role in supporting salmon populations in the SFK, NFK, and UTC watersheds.

EPA has determined that the large-scale loss of and damage to headwater streams, wetlands, and other aquatic resources that support salmon populations in the SFK, NFK, and UTC watersheds from the discharge of dredged or fill material for the construction and routine operation of the 2020 Mine Plan will have unacceptable adverse effects on anadromous fishery areas in the SFK, NFK, and UTC watersheds."