In the case of Minerals Separation North American Corporation v. Magma Copper Company, the U.S Supreme Court was tasked with determining whether or not Magma Copper Company had infringed upon a patent held by Minerals Separation North American Corporation. The patent in question involved a process for extracting minerals from ores and other materials using oil froth flotation. The court ruled that there was no infringement on part of Magma Copper Company as they were using a different method to extract copper from its ore which did not involve oil froth flotation but rather an acid-leaching process. This ruling clarified that patents cover specific methods and processes, and similar outcomes achieved through different means do not constitute infringement.

In the dissenting opinion for Minerals Separation North American Corporation v. Magma Copper Company, it was argued that the patent in question should not be considered valid as it lacked novelty and inventiveness. The dissenting justices contended that the process described in the patent had been previously known and used, thus failing to meet one of the key requirements for a new invention under U.S. patent law - originality or novelty. They also pointed out inconsistencies between different claims within this same patent which further undermined its validity. Furthermore, they disagreed with majority's interpretation of "prior use", arguing that even if an invention has not been commercially exploited but merely disclosed to public without any restrictions on its use, such disclosure constitutes prior use invalidating any subsequent patents claiming such already publicly available knowledge as their own novel inventions.