In the case of Black Diamond Coal Mining Company v. Excelsior Coal Company, the U.S Supreme Court was tasked with determining whether a patent for an invention could be invalidated due to prior use or knowledge by others in foreign countries. The Excelsior Coal Company had patented a method for extracting coal from mines and sued Black Diamond for infringement. However, Black Diamond argued that this method was already known and used in England before it was patented in America, thus invalidating the patent claim. The court ruled against Black Diamond stating that under American law at that time, only prior use or knowledge within the United States would invalidate a patent claim. Foreign uses were not considered relevant unless they were also accompanied by publication which made them accessible to American inventors. Therefore, even if there had been prior usage of such methods abroad without any published documents available to US public about these practices; it did not affect validity of patents granted within US boundaries.

The dissenting opinion in the case of Black Diamond Coal Mining Company v. Excelsior Coal Company argued that the majority's decision to uphold a lower court ruling, which found in favor of Excelsior, was incorrect. The dissent contended that there were significant errors made by the trial court and these mistakes should have been corrected on appeal. Specifically, they believed that evidence presented during the trial had not been properly considered or evaluated. They also disagreed with how certain legal principles were applied to this particular case by both the trial and appellate courts. Furthermore, they felt that some aspects of contract law relevant to this dispute had not been correctly interpreted or enforced by either court involved in this litigation process.