Mineral Park Land Co. v. Howard, 172 Cal. 289, 156 P. 458 (Cal. 1916)
Mineral Park Land Co. v.
Does the doctrine of impossibility/impracticability excuse a promise to take all needed gravel from a particular tract when a substantial quantity of the remaining gravel is submerged and can be obtained only at an excessive and unreasonable cost not contemplated by the parties?
Performance may be excused where, although not physically impossible, it is impracticable—i.e., it can only be accomplished at an excessive and unreasonable cost or difficulty that was not within the contemplation of the parties at the time of contracting. As the court stated, a thing is impossible in legal contemplation when it is not practicable; and a thing is not practicable when it can only be done at an excessive and unreasonable cost. Excuse does not apply where the contract allocates the relevant risk to the obligor or where the increased burden reflects only ordinary or foreseeable difficulties or market fluctuations.
Yes. The contractors were excused from taking the submerged gravel because performance, while physically possible, would have required excessive and unreasonable expense beyond the parties' contemplation; thus, the duty to take that portion was discharged. They remained liable only with respect to the gravel they actually removed.
Mineral Park is a leading early American case articulating impracticability as a form of legal impossibility. It signals that literal physical impossibility is not required; an extreme and unreasonable increase in the cost or difficulty of performance, going to the basic premise of the bargain and not allocated by the contract, can discharge a duty. The decision paved the way for the Restatement (Second) of Contracts § 261 and UCC § 2-615, and it remains a go-to precedent to contrast ordinary cost overruns (which do not excuse performance) with truly extraordinary contingencies that undermine the parties' basic assumptions.