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, leach response and environmental impact. 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 are used to generate economic parameters such as throughput, grind size, grade and recovery and return these to the block model.

This is achieved through the application of a six stage “Geometallurgical Framework”.

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
• Maximize the Net Present Value whilst minimizing risk

The Components of the Geometallurgical Framework

Stage 1 – Multivariate Spatial Domain Definition

To define spatial domains with similar geological, geochemical, geophysical, geotechnical, mineralogical and textural characteristics in the ore deposit taking into account the extensive and integrated information from the exploration drillhole database.

Stage 2 – Sample Selection

To select core samples from exploration drillhole intervals spatially and regularly distributed in either single or multiple domains.

Stage 3 – Parameter Determination

To determine the appropriate processing parameters according to the optimum flowsheet design based on the metallurgical testwork from selected core samples of each domain.

Stage 4 – Multivariate Model Definition

To define multivariate domain models that correlate characteristics such as geochemistry, mineralogy and texture with the processing parameters.

Stage 5 – Multivariate Spatial Model Generation

To apply geostatistical methods to populate each domain of the mineral resources model with geological, geochemical, geophysical, geotechnical, mineralogical and textural characteristics and to compute the Net Present Value of each domain taking into account the mineral processing parameters.

Stage 6 – Joint Mining and Mineral Processing Optimization

To optimize the combined geological, mining, mineral processing, environmental, marketing, economics and corporate strategies to maximize the project value while minimizing several sources of uncertainties, taking into account the extensive and integrated information from the mineral resources model.

The integration of these geometallurgical stages into the traditional test work approach is shown below in Figure 1.

Application of Geometallurgy

Geometallurgy compliments, but does not replace, the traditional metallurgical approach during the development and operation of a mine. Geometallurgical information can be used to;

• Inform flowsheet design
• Size equipment
• Assist in plant design
• Optimize mine to plant performance
• Forecast production
• Reduce risk during feasibility, production and operation

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

Requirements for a Geometallurgical Program

• Technical Publications – Digital copies of existing technical reports and published papers regarding the geological, geotechnical, geophysical, geochemical, tectonic, mineralogical and textural information.
  
  
• Drillhole Database – Digital copy of the existing drillhole database containing collar, survey, geological, geotechnical, geophysical and geochemical information along with any other relevant data.
  
  
• Plans, Cross Sections and Perspectives – Digital Copies of any existing plans, cross sections and perspectives including geological, geotechnical, geophysical, geochemical, tectonic, mineralogical and textural information in addition to any other relevant data.
  
  
• Spatial Interpretations & Models– Digital copies of the existing spatial interpretations (strings) and models (wireframes and/or blocks) including geological and structural information.

Key Technical Deliverables

The key technical deliverables are:

• Understanding of the 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 a monthly/quarterly basis at existing operations.
• Capacity to interface plant performance results with mine planning to refine cutoff grade and optimize mine-mill production.

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.