Image: Aurizona Gold project: Expansion and restart of a gold operation in Brazil

Minerals & Metals2 min read

Aurizona Gold project: Expansion and restart of a gold operation in Brazil

Maranh√£o State, Brazil
Equinox Gold
2017 - 2019

Ausenco worked with Equinox Gold to expand and restart production at its Aurizona gold processing facility in northeastern Brazil. Our complete EPCM contract began with an optimized flowsheet, a more compact site footprint, and included modification of the CIL circuit and upgrades to the crushing and grinding circuits. The plant was successfully restarted, achieving nameplate capacity within several weeks.

The Challenge

The Aurizona Gold mine is an open pit mine located near Godofredo Viana in northeastern Brazil. Constructed in 2010, the plant operated successfully for four years, treating saprolitic ores. In September 2015, all mining and processing operations were suspended, with facilities placed on care and maintenance status.

In November 2016, a 3rd party contractor completed a pre-feasibility study into an upgrade that would allow the site to process a variety of mill feeds at a nominal rate of 8,000 t/d. In 2017, Ausenco was awarded the EPCM for the expansion and restart. and we committed to finding a better way to efficiently execute the necessary plant upgrades to improve gold recovery.

The project involved repurposing and refurbishing various pieces of existing equipment as well as engineering and managing the installation of a new crushing and milling circuit. The remote location of the site, heavy rainfall and complex logistics of the project added an additional challenge to the project.

The Better Way

Making the best use of existing equipment and facilities on site, our team developed a fit-for-purpose design to provide our client with the greatest value for the lowest capital cost.

Our team began with an optimisation of the flowsheet and site layout for the new expansion circuits within the existing plant footprint, to make the process more efficient and more feasible. A careful audit of existing equipment allowed us to integrate upgrades into existing facilities, using new and refurbished equipment where necessary to increase throughput and recovery rates. To enhance gold recovery, we converted the former CIL circuit to a hybrid leach/CIP circuit. Further upgrades to existing facilities included the crushing, grinding and reagents, along with new processing circuits.

Critical to the success of the restart was our strong commitment to safety. Our leadership teams engaged with the local workforce to build a strong on-site culture of safety across the facility through the implementation of site-specific training, auditing, and reporting systems.

The Outcome

The Aurizona processing plant was successfully restarted in May 2019, achieving nameplate capacity of 8,000 t/d almost immediately.

Our Procurement and Construction teams successfully navigated a number of logistics and equipment delivery challenges arising from significant rainfall during critical construction phases, and a shorter than anticipated dry season. The project was completed on time and on budget.

Our focus on safety training and reporting resulted in more than 1.3 million person-hours without a Lost Time Injury.