The Constitutional Tribunal of Peru is to issue a ruling in late March on the case involving the municipal government of Cajamarca and the Yanacocha mining company about a city regulation that bans the exploitation of the gold and copper ore of Quillish hill. The conflict began in October 2000 when the municipality of Cajamarca, in the northern sierra, declared Quillish hill a protected reserve, saying the area is the source of the subterranean waters that supply the city and would be contaminated by mining operations.

In a public hearing before the Tribunal, Yanacocha avoided giving an in-depth response to the matter, but challenged the authority of the municipal council to create protected areas, saying that power belongs to the national government.