Introduction to Geology and Geometallurgy

Transcription

1 Introduction to Geology and Geometallurgy Improving Resource Knowledge to Optimise Minerals Processing: Part 1 Mark Noppe mnoppe@srk.com.au 24 May

2 Why Geology? Improving resource knowledge Rocks and minerals are the basis of all mineral extraction activities An understanding of geology underpins all projects without good geological information, we are just wasting money Linking of geology and metallurgy has long been done empirically and has a long history of collaboration 2 in todays environment it includes all disciplines across the mining cycle

3 Geometallurgy Definition Geometallurgy means different things to different people Geometallurgy is the integration of geological, mining, metallurgical, environmental and economic information to maximize the Net Present Value (NPV) of an orebody while minimizing technical and operational risk Discovery Exploration Assessment Detailed Design Development Production Closure 3 SGS.com

4 Geometallurgy Definition Geometallurgy has reached a maturity beyond its early simplistic geology + metallurgy conception Its application can both maximise value and predict the risks associated with resource development Geometallurgy complements existing approaches to design and optimisation of mining and processing operations 4 Geometallurgy Beyond Conception, S.C. Dominy and L. O Connor, 2016

5 Geometallurgy Definition Key drivers for a Geometallurgical approach Deposits are becoming lower grade, and geologically and/ or metallurgically more complex Orebodies are variable both in terms of grade and metallurgical response this variability is a source of uncertainly that affects plant design, mine design and capital investment decisions Throughputs are increasing and profit margins decreasing, thus financial risk is also increasing Mining project risk needs to be carefully managed for projects to attract funding 5 Geometallurgy Beyond Conception, S.C. Dominy and L. O Connor, 2016

6 Geometallurgy Data Lithology information for ore zones and waste zones/host rocks - mineralogy, alteration, and veining, etc Structural information - faults, foliation, schistocity Geotechnical information Geophysical data - density, magnetics, chargeability Metallurgical data - gravity recovery, flotation recovery, magnetic recovery, crushing work indices, hardness, UCS, grindability indices Interpretations of integrated hyperspectral, digital photos, PIMA and observed geology data Integrated 3-D models created for use for planning and forecasting 6

7 7 Case studies

8 Ni-Sulphide mine, WA The Resource Model was not a good predictor of the actual grade, density and grindability of the ore Poor Resource to Mill reconciliation Mine operations could not rely on the model for short-term production planning 8 Grade control activities identified clear zones of magnesite alteration, not recognised or modelled in the Resource Model When correctly mapped and modelled, the alteration domaining helped improve reconciliation due to Hardness and grindability Bulk density Grade per tonne versus grade per cubic metre

9 Hill End Trial Mining Objectives Improve resource knowledge Improved understanding of grade distribution & geological controls Improve processing knowledge 90.4% recovery from nominal 1 mm grind; Staged grind and Knelson concentration to capture coarse gold; Finish concentration on tables Issues Generally poor reconciliation between face and batch mined grades (drive and stope) Deposit difficult to scale up (mining tonnage constrained, no electricity UG) Trial plant (5 tph) did not easily allow for scaleup testing

10 Hill End Ore Sorting Test Work Ore Sorting Initial evaluation of ore samples - multiple sensing systems tested Gold is in quartz veins hosted by shale i.e. pre-concentration of gold in geologically identifiable host Colour recognition in natural light (quartz ore & shale waste) most effective Test work achieved 75% rejection of unmineralised slate* 95% of gold in quartz retained* Issues Fines would not be sorted proportion unknown Hill End HG (8-12 g/t Au) and LG ( g/t Au) in separate deposits, with different economics * HEG QR 31 January 2011

11 Thank you Mark Noppe 11