A long-term and ongoing gold technology research program, driven from Australia since 1994, is delivering global outcomes including lower mineral processing costs, improved recovery of valuable metal and significant advances in environmental management. The Project 420 program of technology transfer and improvement is in its sixth iteration and is preparing for a seventh.

The program focuses on a collaborative approach to software modelling in the metallurgy space and at a cost to date of just under Aus$18 million it is conservatively estimated that Project 420 has improved efficiencies and gold processing modelling to save more than Aus$200 million in operational costs over the past two decades, and has identified opportunities for recovery increases and lowering of losses to the tune of Aus$20 million a year.

The project operates under the banner of AMIRA International, the member-based organization of minerals companies and suppliers which has developed, brokered and facilitated collaborative research projects since 1959. AMIRA International has its head office in Melbourne, Australia, and also has bases in South Africa, the USA and Chile.

Project 420 spent its early years under the guidance of the Parker Centre, an Australian Co-operative Research Centre which closed in 2012, and since then it has made its home at Western Australia’s Curtin University, within the university’s Gold Technology Group, under the leadership of Professor Jacques Eksteen.

AMIRA’s managing director Joe Cucuzza says that the benefits and breakthroughs of Project 420 have included development of a suite of software models to simulate and optimize carbon management within carbon-in-pulp and carbon-in-leach circuits, optimization of grind size for gravity and leach recovery, an integrated approach to deportment of gold in operational circuits, a general improvement in recovery of valuable metal, and a better understanding of ore characterization.

In addition, significant inroads have been made in the area of pre-concentration and coarse particle gangue rejection, allowing a fresh look at low-grade ores. The inroads extend to the development of new benign leach reagents such as amino acids for the leaching of gold, silver and copper minerals which AMIRA believes may prove to be transformational for the industry.

Joe Cucuzza says that one sponsor representative reports that in the latest and sixth iteration of Project 420, a single mine-site in South America had utilized the technology to realize more than Aus$6 million a year in cost savings and recovery improvements.

Another sponsor, St Barbara Limited, says that guidance from the Project 420 team has led St Barbara to specific cost-saving initiatives which have delivered company-wide savings of several million dollars over the three-year project term.

“Improved gold processing knowledge by the plant metallurgists, as a result of the on-site workshops, led to better gold leaching, elution and carbon management practices. This resulted in increases in gold recovery and lower plant operating costs,” according to St Barbara’s senior project metallurgist.

Each iteration of Project 420 is for three years with iteration six due for completion at the end of May 2016. A total of 14 member companies across the world have funded the latest program, and they share in the benefits.

Curtin University’s Professor Eksteen says that the current iteration of study is making significant advances in understanding the fundamental issues that affect the flotation of pyrites and the related recovery of gold.

“The success of the project has led to the implementation of a graduate training program. With a focus on technology transfer, tailored training direct to mine-sites is now available to increase the capability of site metallurgists to solve complex hydro-metallurgical problems,” he says.

Under AMIRA’s patronage, industry is now preparing to implement iteration seven of Project 420, with a focus on enhancing gold mining economics to improve processing and extend ore reserves. In doing so, it will have available to it more than 30 years of knowledge and experience, data bases, models and software.

Iteration seven will also focus on reducing the cost of processing lower-grade material and difficult ore types as well as lowering inputs of water and energy, and managing poorer or variable quality water used in minerals processing. It will also focus on improving capital and labour productivity, and maintaining social license to operate.

With 20 years of experience, project economics have cumulatively and dramatically improved. Professor Eksteen estimates that the seventh iteration, due to start in mid-2016, is expected to deliver at least a 15:1 leverage on investment for mine operating partners, and a 30:1 leverage for mine-supply member companies.