The Fifth Circuit Court of Appeals is reviewing a contract dispute between a U.S. chemical manufacturer and a Mexican mining company that centers on licensing obligations for the international sale of sodium cyanide used in gold and silver extraction operations.

In *Cyanco International, L.L.C. v. Minerales de Occidente, S.A. de C.V.*, the appeals court is examining whether the parties properly fulfilled their regulatory obligations under a supply contract for sodium cyanide, a chemical essential to heap-leach mining operations. The case was filed Jan. 29, 2026, and stems from an appeal of a Southern District of Texas ruling in favor of the Mexican mining company.

Cyanco International, a producer of sodium cyanide, had contracted with Minerales de Occidente ("Minosa"), an open-pit heap-leach mining company, to supply the mining firm's annual requirement of sodium cyanide. The chemical is commonly used in gold and silver mining operations to extract precious metals from ore through a leaching process.

The dispute arose when regulatory compliance issues emerged regarding the proper licensing for international transport and use of the chemical. Both parties were required to maintain appropriate export and import licenses under Bureau of Industry and Security regulations due to the controlled nature of sodium cyanide.

The Fifth Circuit's review will determine whether the lower court correctly interpreted the contractual obligations and regulatory compliance requirements that governed the commercial relationship between the U.S. manufacturer and Mexican mining operation.