Geometallurgy, a technique that improves accuracy in mining and the extraction of minerals and which starts during the exploration phase, is becoming one of the most important tools in mine planning, optimising and increasing net present value (NPV) for projects, says geological services company Minrom director Oscar van Antwerpen.

“This is the single most important driver to demonstrate upside potential and attract investment,” he adds.

Geometallurgy is the process of integrating geological, mineralogical and metallurgical information to predict the performance of an orebody during mining and processing and allows for more efficient and cost-effective resource extraction.

While geometallurgy does not replace traditional geological work, it “adds another layer of understanding” to the evaluation process as it affects the ore characteristics of the whole orebody through a superimposition of information onto the 3D geological block model.

“Geometallurgy is an addition to the traditional resource estimation work . . . The resource estimate remains the primary focus, as it forms the foundation for all future mine plans and financial models,” adds Van Antwerpen.

Once the orebody has been characterised, geometallurgy enables the development of a reformatted mine schedule – an integral component derived from sampling and during the resource estimation.

Poor geological modelling, Van Antwerpen cautions, causes many projects across Africa to collapse – evidenced by multiple projects that he has encountered.

“The reason for failure is as basic as junior exploration companies staffing projects with geologists who lack the necessary experience and logging skills to identify a key number of ore characteristics. This results in error propagation which is ultimately carried through to the geological model, influencing the financial assessment and valuation of the deposit”.

He stresses that failure to follow proper exploration protocols and build an appropriate geological model from a valid database creates problems downstream, as inaccurate models lead to erroneous recovery assumptions, inflated grade expectations, inaccurate financial modelling and incorrect production scheduling.



Ore Characteristics

Geometallurgy takes into account not only ore grades but also ore characteristics and behaviour in a processing facility.

“Certain ore types recover well under certain conditions, and geometallurgy enhances operational efficiency by allowing for the planning and scheduling of material based on its processing behaviour and extractability in the process plant,” adds Van Antwerpen.

“The real value comes when a company optimises and reschedules the mine plan, driven by a reduction in both operational expenditure and capital expenditure [capex] costs. We often see an increase in a project’s NPV and a decrease in capital cost estimates when geometallurgy is applied.”

He notes that the geometallurgy approach is assisting with capex estimates upfront, helping to reduce construction costs and overall capital requirements as the technique allows different ore types to be aligned more effectively within the mine plan.



AI Needed for Data

Applying modern geological exploration techniques creates complexities when it comes to database management and assessment owing to the large variety in data types. These complexities and interdependencies are often overlooked or difficult to deduce, and this is where the implementation of machine learning modelling can be used to enhance the understanding and formulation of exploration targets.



While data could be synthesised by humans in the past, decades of mapping, drilling and exploration have produced data volumes too large to process manually, notes Van Antwerpen.

These methods, he believes, are also crucial for junior firms trying to attract investors to a tough market, but into which a lot of funding is allocated. 

“The race is on to determine who will attract the capital in the future, and its sources. You need to support your project with the best possible information and modelling, demonstrating the liquidity and value of your project.”