The core of the Superfund deal itself, and how it proposes to solve Butte’s lingering environmental problems forever, is really important and complicated, both legally and technically. And no wonder. Three levels of government — the county, state and feds — plus a former oil company, all had to settle their differences, and agree on how to clean up, once and for all, the rest of the environmental bust left behind by Butte’s historic copper mining boom.