LIVING THE DREAM: EVALUATING THE POTENTIAL EFFECTS OF MINING A WORLD-CLASS MASSIVE SULFIDE DEPOSIT ON WISCONSIN’S WATERS - NOT ONCE, BUT TWICE

Exxon Minerals discovered a large zinc-copper sulfide ore body in Precambrian terrane in northern Wisconsin in 1975 and initiated permitting to mine the orebody in 1976. This part of northern Wisconsin is wet with numerous perennial lakes and streams and many wetlands and seasonal water features. A short time later, Ken Bradbury arrived in Madison to pursue a PhD in hydrogeology at the University of Wisconsin, presumably unaware of how his chosen career path would intersect with the desires of others to mine that orebody.

Ken’s first connection with the Crandon deposit was through his PhD advisor Prof. Mary Anderson, who was helping the state evaluate the proposed permits. When Ken graduated and joined the Wisconsin Geological and Natural History Survey in 1982, he continued to help the state assess potential effects on water resources until Exxon withdrew its applications in 1986. In 1994, Exxon and a Canadian partner initiated a new permitting process for the Crandon deposit and the state quickly retained Ken and the state survey to help with the new review. The second review process lasted until 2003, when the project was sold to two nearby Native American Tribes and withdrawn.

During the first permitting process, two groundwater models were developed to assess the mine inflow, drawdown, and associated effects on area surface waters – one by the proponent and one by the team supporting the state’s review. The second permitting process, with the advancement of groundwater modeling tools, included the development of four model iterations by the proponent, two by the state’s team, and several more initiated by federal agencies, Tribes, and others. Lively discussions with the proponent and others focused on topics of conceptual models, boundary conditions, parameters, and other assumptions about the geologic setting, hydrologic connectivity, and effectiveness of project design features. In the end, results varied by about a factor of three in predicted hydrologic impacts.

Ken’s strong geologic background, expertise in groundwater modeling, thoughtful approach to engaging with others, and strength of character helped the state navigate through two rounds of highly contentious permitting for this orebody rich in minerals important for the transition to a low carbon economy. Ken stepped up to help twice. What will he do if it is proposed a third time?