I see there's a lot dreamers out there who hope&wish there is a way to operate a mining operation at Pebble without damaging the environment and keeping ZERO-risk to the fishery...
...sorry to tell you there is NO pathway to a big-profit biz-plan that fits any standard economic model.  There is no way you can make enough profit from Pebble to support an office and engineering staff located in any city, not Anchorage or Vancouver or anywhere. The only feasible management office would be a small crew of volunteer students and staff at UAA&UAF.

The only way to operate Pebble is to work it as an environmental cleanup operation slowly over many centuries of time [300+ years]

It can be safely operated by local-Alaskans as a small slow-go surface extraction & cleanup operation using only extreme oversight with top-grade hi-tech equipment. Just for a few hundred fishermen/miners as good-pay local work.

PEBBLE is NOT an opportunity for any outside mining company, invest in asteroid mining.