Initial cyanide pre-audit at Dolores Mine, Mexico Initial cyanide pre-audit at Dolores Mine, Mexico Initial cyanide pre-audit at Dolores Mine, Mexico

Initial cyanide pre-audit at Dolores Mine, Mexico

The Dolores gold and silver mine, operated by CM Dolores, is located in the Sierra Madre Occidental mountain range about 250km west of Chihuahua in northern Mexico. The mining company were keen to ensure they were protecting the environment and employees from cyanide, and being compliant with the cyanide code as accredited signatories.

We were commissioned to carry out an initial review of cyanide management at the mine, using the cyanide code as a tool to assess the current status. The processes we audited included a heap leach pad operation (using sodium cyanide) as well as the Merrill Crowe gold separation process. The audit included auditing and testing the emergency response procedures for both human and environmental exposure.

Our pre-audit findings included a number of key recommendations for improving cyanide handling and management. These included making sure correct PPE is worn, establishing an inspection and maintenance programme for the HLP/solution ponds' geosynthetic liners, ensuring legal compliance with Mexican issued permits and licences, and revising the cyanide awareness training records and programme. Implementing these will help the owners of the mine to make sure that key processes are compliant with the cyanide code.