SUTTON, Chief Judge. Century Aluminum relies on river barges to obtain alumina ore and other materials that it smelts into aluminum. When the Army Corps of Engineers closed key locks on the Ohio River in 2017 due to low water levels and mechanical breakdowns, Century scrambled to secure other transportation. Century filed a claim with the underwriters of its maritime cargo insurance policy, referred to collectively as Lloyd’s of London, for these unanticipated shipping expenses. Lloyd’s paid the company $1 million under the policy’s Extra Expense Clause but denied coverage for the rest of the claim. The district court granted summary judgment to Lloyd’s. We affirm.