Antamina produced an Environmental Impact Study (EIS) that was approved by the appropriate authorities. It was made public and communities in its area of influence were consulted prior to its presentation in March 1988.

Addressing suggestions from the communities, the Government and different organizations, two addendums were subsequently added to the document. The first modifies the access route to the mine. Rather than using the central route through Huascarán National Park, a southern route was proposed that borders the park. Secondly, the transport method for the concentrates was changed to a pipeline rather than trucks, among other changes.

The mitigation measures for possible impact identified by the EIS take into consideration recommended health, safety and environmental protection standards and practices, established by Peruvian legislation, Canadian norms and the World Bank.