In January 2000, ADELA was a party in a lawsuit seeking an injunction and annulment of the HCRH exploration concessions. In September of that year, the Costa Rican Constitutional Court ruled in ADELA's favor, and granted an annulment of the four-block HCRH concession. The Court's ruling was based on International Labor Organization Convention 169, "Concerning Indigenous and Tribal Peoples in Independent Countries," to which Costa Rica is bound. The Court later modified the ruling in November 2000, however, and nullified only those blocks affecting indigenous territory.