The Berkeley Pit in Butte Montana has a water problem. Though the EPA is involved in treating the water for heavy metals and other pollutants the water increases more than the rate of treatment, and might reach the Clark Fork someday. The Berkeley Pit was at one time perhaps the largest open copper mine in the world. Finding a long-term solution to the problem of treating mining wastewater needs to be found for not just that particular pit- it is a mining problem for communities around the nation and world.
If the polluted water reaches the Clark Fork and Snake, Columbia Rivers drinking and agricultural irrigation water- not to mention fishing, would be adversely impacted. Mining should really be accountable for the lasting damage to aquifers.
If President Trump wants to improve his damaged environmental protection reputation it might be worthwhile fixing the Berkeley Pit problem. I wonder if evaporation with geothermal heat with the vapors absorbed by some substance that could be embedded in concrete at some safe place- such as building a concrete border security wall, would be a cost effective environmental remedy. Of course toxic metals could be removed from the vapor where possible, or the water could flow through a powerful electromagnetic field in pvc pipes with the metals segregated from the water.