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22 SEG NEWSLETTER No 90 • JULY 2012 SEG NEWS SEG GEOMETALLURGY FORUM Geometallurgy – The Journey A lot of what we do in our professional careers is about project. Projects are great. They have a start, a middle, and an end. If things have gone as planned, at the end of this process we have achieved our goals—our targets—and we can feel happy about a job well done. Unfortunately, geometallurgy is not like that. Geometallurgy is a journey or, as I find myself telling people, “it is a commitment.” Of course, the geometallurgical journey can and will be broken into steps or phases that resemble projects, but overall, it is one long journey. The key areas the geometallurgy journey can be subdivided into are the technical journey, the management journey, and the business process journey. It is worth looking at each of these, as they all relate to the successful integration of geo - metallurgy into the business of a mine. THE TECHNICAL JOURNEY One of the key deliverables from a geometallurgical program is a forecast of expected production output on some time basis (such as quarterly, monthly, or if you have been at geometallurgy for a long time, weekly basis). The forecast will be of key concentrator outputs, such as mill throughput, mill primary grind size, recovery of wanted metals, and concentrate grade. This forecast will be based on a model interacting on the block model with expected feed blocks for that time period. This model then calculates the expected outputs based on some independent variables (such as head grade, mineralogical make-up, grindability hardness index). Having made a forecast, we want to know how good our forecast was. Its accuracy is calculated by a reconciliation. We determine the actual throughput, primary grind size, recoveries, and concentrate grade for the target period and compare it with our forecast (actually, the reconciliation process is a lot more complex a process than this, but that is another discussion). We then determine the error band between actual results and forecast and decide if that forecast was good, acceptable, or poor. Then the process gets repeated. We do another monthly or quarterly forecast and reconciliation. Time and time again we repeat this process because stevewilliams@geomettech.com this is essential and this is how we realize the value in geometallurgy. At some point in this repeating cycle we will review our model and our underlying assumptions in the forecast (which could be the independent variables, the domains, or the model itself). These will be reviewed and if through our journey to this point we have learned new things or understood things better, then we may enhance or modify some of these components. The models used to make these forecasts would be expected to evolve and perhaps be radically recast over the life of a mine. Models designed in a mine project’s prefeasibility or feasibility stage of development are often simplistic as they are used only to forecast annual production for the feasibility study. However, it is logical to use these models or some enhancement of them at the commencement of production. Equally, it is logical to expect that these models will be refined, enhanced, or changed over time as more things are learned about the fundamental geological drivers for comminution and flotation or leaching. It is a long way from an acceptable error band on yearly forecasted production to achieving the same error band on monthly forecasted production. Another area that evolves with time is the delineation of the geometallurgical domains. Geometallurgical domains are those zones or areas that have commonality in some aspects of metallurgical performance (such as recovery and/or resultant concentrate grade quality). The domains are made to help us understand a complex geological system by clumping together these areas of similar types of performance. It should also be pointed out that there will be different geometallurgical domains for comminution and for mineral concentration (such as flotation). When a geometallurgy program be - gins, it is impossible to know what and where these geometallugical domains are (because it requires that metallurgical result feedback loop), so inevitably, initial geometallurgical domains are built up from the geological domains of the deposit, but with the application of some geometallurgical principles. The geological domain approach is a good starting place for geometallurgical do - mains but in evitably the geo metallurgical domains will change or evolve from there as we carry on through the mine life. Typically, STEVE WILLIAMS (SEG 2010) with porphyry copper-type deposits, there are fewer geometallurgical domains than geological domians. Some geological domains have very similar metallurgical performance. Eventually, these domains will be clumped together to form the geometallurgical domain. However, for other geological entities, this is not the case. For VMS-type de - posits, the geological domains do not well capture the flotation complexities of these deposits. So, in this case, we may see the evolution of more geometallurgical domains than geological domains, as we try to better describe the metallurgical performance of that deposit. It can thus be seen that the technical world of geometallurgy is a journey, with future learning leading to evolution of models, domains, and key assumptions that change with time. THE MANAGEMENT JOURNEY Geometallurgy crosses boundaries from geology to mine planning to metallurgy. It also touches on areas such as product quality/marketing, projects, and exploration. Given this breadth of reach of geometallurgy, it means that geometallurgy is a mine management theme. Specifically, a mine that is implementing a geometallurgy program cannot just say that “this is a geology task or a metallurgy task.” To do so would not recognize the breadth and value of geometallurgy and would inevitably doom the program to probable failure. There are a number of real management issues relating to the successful implementation of geometallurgy in a mine or mine development project. Some of the key issues include the following: structure, reporting lines, geometallurgy management, reports, decision-making, communication, and language. This list is large, with some real challenges, and as with any of these human issues, particularly as they relate to change (change management), these issues are not addressed once and then resolved. This is a process or a “commitment”! What is important is to
JULY 2012 • No 90 SEG NEWSLETTER 23 recognize the management issues and recognize this as a change management process. Then, the task becomes more defined and the journey can unfold. It is worth commenting on a few of the key issues here. The first issue of structure and reporting lines is challenging without any necessarily right answer. Two structures are commonly seen. Firstly, a project-style geometallurgy team can be formed consisting of key members from geology/mine planning and metallurgy. This team could have a senior manager assigned to that group for guidance and monitoring. This system works if the senior manager then recognizes that he or she is the assigned manager and he/she takes the responsibility to get the buy-in of the other key peer managers in the progress of the geometallurgy program. The second structure that is seen is to have an independent geometallurgy group reporting to senior mine management with clients in geology/mine planning and metallurgy. This structure works as long as the key line groups of geology/mine planning and metallurgy see geometallurgy as important to their objectives. The second very challenging issue faced for geometallurgy is one of communication and language. Geologists, mine planners, and metallurgists are trained differently and use different jargon to communicate their ideas. This presents a real challenge to geometallurgy, which straddles all these technical areas. There is no simple answer to this problem except for time, persistence, and “commitment.” Another journey! THE BUSINESS PROCESS JOURNEY Geometallurgy brings value by allowing for a more holistic view of optimizing mine project economic return. Geomet - allurgy considers not only grade and pit plan but also throughput, recovery, concentrate grade, and quality (and other issues if so configured, such as some environmental impact issues) in determining economic output. After all the results of a particular mining scenario are considered, it is then possible to carry out sophisticated economic optimization processes. Again, this is not just an exercise for mine project feasibility; when incorporated into the mine operations, it becomes a fundamental part of the whole mine business process. This is then a sequence of continuous feedback and economic optimization as the mine is developed. The business process is a journey. The first part of this journey is one of change in the way we make those economic decisions about the mine operation. Here, we have more change management. Overall, geometallurgy is still seen as a technical tool and at its roots, it is technical. However, the value comes from making business decisions based on the information provided by geometallurgy process. The challenge presented to mine operations is to recognize that making these geometallurgically based “optimizing” business decisions is not only how to realize value but also is a necessity for improvement and success. This journey for the business of mining, with a few exceptions, has only just begun. Geometallurgy can bring much additional value to mining operations. How - ever, it is not a project with some quick, identifiable objective. It is a long-term journey. On all the fronts, be they technical, management, or business process, it is a process, a journey, and a commitment. For me as a practitioner, advocate, and leader of geometallurgy, this has also been a journey. Geometallurgy is still relatively new and so is challenged, sometimes treated skeptically, sometimes over-embraced, and definitely still with much learning and evolution ahead. There have been successes and other results that are less encouraging. This is part of what any new management process will go through. 1 SEG NEWS The Australian Institute of Geoscientists with Geoscientists Symposia present SYMPOSIA • Structural Geology and Resources 2012 Kalgoorlie, WA 26th-28th Sept • East Asia: Geology, Exploration Technologies and New Mines 2013 Bali, Indonesia 27th-29th May FIELD TRIPS AND SHORT COURSES 2012 • Yilgarn Field Excursions WA 20th-23rd Sept & 29th-3rd Oct • Porphyry Copper Workshop Perth, WA 21st Sept • Up-skilling Workshop: Structure and Exploration Kalgoorlie, WA 24th & 25th Sept • Non-linear Processes and Non-equilibrium Thermodynamics without Complex Mathematics Workshop Kalgoorlie, WA 29th Sept For details: www.aig.org.au Presenting a paper or sponsorship: Julian Vearncombe: julian@sjsresource.com.au or Trade booths and registration: Jocelyn Thomson: jaytee@iinet.net.au PAID ADVERTISEMENT PAID ADVERTISEMENT
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