Geometallurgy Overview

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WHAT IS GEOMETALLURGY Geometallurgy is the geologically informed selection of a number of test samples to determine metallurgical parameters and the distribution of these parameters through an orebody using an accepted geostatistical technique to support metallurgical process modelling.

The distribution can be influenced by the geological structure of the ore body, in that the lithology can have an affect on some of the parameters.

Geometallurgy quantifies the variability of the ore deposit in terms of process parameters such as ore hardness, flotation kinetics and leach kinetics. The data is then applied to the deposit block model or the mine plan, typically through use of geostatistics.  After this, geometallurgically enabled mathematical models, “GEMs™“,for grinding and flotation are used to generate economic parameters such as throughput, grind size, grade and recovery and return these to the block model.  The models currently available, FLEET® (Flotation Economic Evaluation Tool) and CEET® (Comminution Economic Evaluation Tool) are capable of handling large data sets in an operational secure environment.

Geometallurgy complements, but does not replace, the traditional metallurgical approach during the development and operation of a mine (Figure 1). Geometallurgical information is used to inform flowsheet design size equipment assist in plant design optimize plant and mine to plant performance forecast production reduce risk during feasibility, preproduction and operation.

THE BENEFITS OF GEOMETALLURGY
Geometallurgy significantly reduces the impact of spatial uncertainty in mine planning because it documents the variability in a deposit. This lowers project risk by enabling:

• rigorous documentation of geological and mineralogical impact on metallurgical performance and grindability
• plant design that recognizes the inherent variability of the deposit
• forecasting of production parameters such as plant throughput, grade, recovery, P80 and concentrate grade on a quarterly or yearly basis, with a statistical confidence interval
• optimization of  plant performance with respect to ore variability
• effective mining of the ore over the entire mine life
• optimized mine resource and plant performance

WHAT PROJECTS BENEFIT MOST FROM A GEOMETALLURGICAL APPROACH?
Geometallurgy is a cost-effective technique used to characterize ore variability during any stage of exploration, development or operation. It is well suited to:

• Highly variable or strongly zoned deposits
• Several close deposits that will be milled together
• Remote or deep deposits that are readily drilled but not easily bulk sampled
• Projects requiring complex or new metallurgical approaches
• Brownfields or sight-of-mine exploration and expansion projects that exploit new, deeper or adjacent reserves
• Projects with significant legacy drill core that are being reevaluated due to new economic circumstances

THE COMPONENTS OF GEOMETALLURGY
As seen in Figure 2, geometallurgy consists of several component activities including

• Sampling
• Variability testwork, using standardized, low-cost tests that require a small sample volume
• Related data collection and correlations
• Addition of data into block model or mine plan
• Geostatistical data handling
• Process modeling

KEY TECHNICAL DELIVERABLES

The key technical deliverables are:

• Understanding of linkages between geology, mineralogy and metallurgical performance
• Robust flowsheet that will effectively process ore over life-of-mine
• Optimized sizing of plant equipment given ore constraints, operational costs and physical constraints
• Capability of predicting and modeling plant performance within known statistical parameters.  Can generate average expected recoveries, grade, throughput, P80 and concentrate grade values on a block-by-block or year-by-year basis.
• Ability to forecast and reconcile production on monthly/quarterly basis at existing operations
• Capacity to interface plant performance results with mine planning to refine cutoff grade and optimize mine-mill production

GEOMETALLURGICAL ACTIVITIES DURING PROJECT DEVELOPMENT The geometallurgical approach can be implemented as an integral part of Greenfields development of a mine, starting during reserve development (i.e. with conceptual metallurgical studies) and as part of prefeasibility and feasibility studies and on into operations (Figure 3) Existing operations requiring production forecasting support (Figure 3)

GEOMETALLURGICAL DELIVERABLES
The table below presents the deliverables and benefits associated with each component activity.

EXPERTISE
SGS is the market leader in using geometallurgy. For 5 years we have been actively developing and applying this approach to project development. We typically run 12-15 programs a year for projects at any stage of development or large and small companies throughout the world and share our intellectual expertise in this field with many global companies.  We currently are subcontracted to perform production forecasting at 5 mines producing gold, copper or iron ore.