The U.S. Supreme Court case Oliver Iron Mining Company v. Lord et al., 1922, revolved around a dispute over the interpretation of a mining lease agreement between the Oliver Iron Mining Company and landowners in Minnesota. The issue at hand was whether or not the company had to pay royalties on iron ore it extracted but did not sell due to its low quality, which made it unsuitable for commercial use. The court ruled in favor of the landowners, stating that under their lease agreement with Oliver Iron Mining Company, they were entitled to receive royalties based on all iron ore removed from their property regardless of its marketability or subsequent use by the company.

In the dissenting opinion for Oliver Iron Mining Company v. Lord et al., Justice Holmes argued that the Minnesota tax law, which taxed iron ore at a higher rate than other real estate property, was not unconstitutional. He disagreed with the majority's view that this constituted a violation of equal protection under the Fourteenth Amendment. Instead, he contended that states have broad discretion in their taxation policies and can classify different types of properties for tax purposes as they see fit. In his view, it is reasonable to consider iron ore as distinct from other forms of property due to its unique characteristics and economic value; thus justifying differential treatment in terms of taxation rates. Furthermore, he pointed out that there are many instances where unequal burdens result from state laws without necessarily violating constitutional principles.