Biox® Tank Farm Design (Runruno)


The BIOX® process is an environmentally friendly process used by GoldFields in the refractory of gold ore in the metallurgical extraction stage. This process uses 3 types of bacteria which accelerate the oxidation of the sulphides in gold ore to free the gold. A large volume of air is pumped through the slurry using spargers to supply the bacteria with enough oxygen and carbon dioxide for the oxidation reactions and cellular growth of the bacteria.
A Solid model of a Biox tank
The reactors are constantly cooled by circulating water in cooling coils as the oxidation reactions are exothermic and the slurry temperature needs to be kept at an optimum temperature. An agitator mixes the low pH and high temperature slurry to ensure thorough penetration and even concentration of the active elements.

AXIS Mechanical Design was contracted by Contromation Energy Services to design 8 BIOX® reactor tanks with their top structures which are interconnected with platforms, walkways and launders in the Runruno BIOX® plant in the Philippines. Harsh environmental conditions provided some unique challenges to the project such as a site that is located near active fault lines and temperatures above 40 degrees Celsius in the summer months.

The 4 Primary and 4 Secondary BIOX® tanks had to conform to universally accepted Codes and National Codes which included: The design of the plant consisted of the following subsystems: 3D CAD models were built of the tank, top structure, baffles and the sparger and Finite Element Analyses were done to verify their design for the loads as described as above. A shell model was also built for the tank and the top structure to more accurately analyze the seismic loads acting on the tank and top structure. The models were built using SOLIDWORKS 2012 and the analyses were performed using SOLIDWORKS SIMULATION 2012. A complete detailed report on the design and the results found and a set of fabrication drawings was supplied to the client within the project deadline. Similar Projects that Axis Mechanical Design has successfully completed includes: