Wisconsin Electric Power Co. can’t shake breach of contract claims for entering into a Superfund settlement with the EPA after signing an agreement to conduct a cooperative cleanup study with other parties, the U.S. District Court for the Eastern District of Wisconsin said.

Cliffs Mining Co. may proceed with claims that WEC Energy Group subsidiaries Wisconsin Electric and Wisconsin Gas LLC breached a joint participation and defense agreement by striking a later agreement with the agency, the court said.

Cliffs alleges the companies breached their duty under the 2007 agreement to conduct a common response and to conduct a remedial...