Book Review: Metallurgical Plant Design

  • By Dean David, Technical Director - Process, Amec Foster Wheeler Australia West

Metallurgical Plant Design by Boom R, Twigge-Molecey C, Wheeler F, Young J. Published by Canadian Institute of Mining, Metallurgy and Petroleum, 2015, ISBN 978-1-926872-27-8

As a first note, this book uses design and project implementation examples from steelmaking and aluminium with a minor contribution from hydrometallurgy. There is little, if any, direct reference to the processing of ores at the mine site (typically in in concentrators and leach plants) and this means it has some limitations in regards to the direct experience of many AusIMM members. For those members in steel and aluminium its case studies and references will no doubt have high value.

As a mineral processor myself, I did have some difficulty following the message when some of the finer details of steel plant design were being discussed. However, this did not occur as often as I feared. The fundamental message as to how process design should be carried out is not compromised greatly if the reader is unfamiliar with the steelmaking world.

The book is written primarily by employees or associates of Hatch. Although I work for a competitor, the majority of the design and management ideas expressed are common with my own organisation and are appropriate guidance for anyone working on design projects. There is a substantial and timely Australian contribution with the Sustainability in Plant Design chapter authored by Philip Bangerter, Dr Glen Corder (both with whom I have worked), Damien Giurco, Ben McLellan and Andrew Murphy.

Interestingly the first full chapter is on Risk Based Design and, from a structure viewpoint, I would have preferred the book to have opened with Chapter 5, which discusses typical Project Development stages. The reference framework discussed in Chapter 5, and used throughout the book, is the Front End Loading (FEL) nomenclature (from FEL1 to FEL4) which runs parallel to the Scoping, PFS, FS and implementation phases followed by many Australian companies and embodied in JORC. My major problem with the FEL concepts when espoused by mining/processing clients is that there is an unrealistic assumption as to how much is able to be ‘known’ in a definitive sense at each stage, especially when exploration drilling is still happening at full pace.

General Risks throughout project life are covered well in Chapter 1 and the Technical Risks are covered in some detail in Chapter 6. However, as an insider on some of the Ni-Laterite history in WA the risk discussion information related to these projects is somewhat superficial and a bit misleading.

Chapter 3 deals with setting up the Business Case for projects and Chapter 4 deals with Site Selection. Both chapters are clearly angled towards steelworks and similar projects that have the ‘luxury’ of sourcing a variety of feedstocks globally and being situated to take advantage of transport, power and markets.

Chapter 7 deals with the complexity of Custom Designed Equipment and has some synergies with the introduction of new technologies or flowsheets in mineral processing plants. In the examples presented it is not often possible (or useful) to pilot the innovation within reasonable cost and schedule, so valuable design phase strategies have been discussed that minimise full scale implementation risk.

Chapter 8 deals with Sustainability issues and is applicable across the full spectrum of resource industry projects. There are useful guidelines, tools and resources identified in the text and I found it an extremely useful read in terms of understanding the interface between major projects and the general population that are (simultaneously) disrupted and served by them. If there is a criticism of this chapter it is that the complexities of the client–engineer relationship are not fully explored. It is this relationship that is the key to ensuring the design (the primary responsibility of the engineer) reflect fully the sustainability demands placed on the project (typically the realm of the client and their separate environmental consultant).

Chapter 9 covers Safety in Design and looks closely at issues under the control of the design engineer. Although steel-focused, the discussion is clearly applicable across all resource engineering projects. One area that I believe could have been dealt with in more detail is the overlap of construction and commissioning activity. For construction teams the parallel initiation of commissioning activity is a fundamental workplace change. The site, or a site component, changes in the space of a day from being somewhat benign steel, concrete, wiring and equipment to being partially energised/operational. Design thought is essential if construction is to continue safely while nearby equipment is active or potentially active.

Chapter 10 covers Plant Layout and Logistics and is, again, steel project focused but has reasonable application across most resource projects. Issues of site characteristics, understanding workflow, 3-D design and understanding how the plant is actually going to operate using simulation are needed on all projects. Of particular note is the influence that uncertain operational outcomes (for example, unplanned maintenance) must have on design thinking. The text describes with clarity why failing to incorporate uncertainty through stochastic modelling results in dangerously incorrect design outcomes.

Chapter 11 is a reasonably comprehensive discussion on Project Implementation and is a good resource for those engineers that are involved in the study phases that may not appreciate what is needed to build a substantial project. The complexity of project implementation, and the associated need for certainty in this phase (FEL4), are clearly demonstrated.

Chapter 12 is titled Looking to the Future but is somewhat a picture of the present. Increasingly out of alignment with the heading, it describes a past project. Upon reading it I felt an opportunity for vision was missed in this chapter.

I do recommend the book to AusIMM members, but on the proviso that the fundamental differences with orebody-based projects are recognised. These include:

  1. The necessity of co-location of plant and orebody for almost all projects
  2. The uncertainty of the plant feedstock, which changes with
    1. ongoing exploration activity
    2. geometallurgical analysis
    3. metallurgical testing
    4. changing mine plans
  3. The above uncertain factors usually mean that at the completion of the PFS (FEL2) the engineering extent is not 10-40per cent (project definition deliverables maturity level in Table 5-1) but is better assumed to be at 0 per cent.
  4. The uncertainty also means that many factors shown in Table 5-1 as Defined (such as plant layout) or Complete (such as P&IDs) are premature at the completion of the FS (FEL3). Attempting to be this advanced in FEL3 invariably results in wasted effort as this detailed work can only be done when all information is available and signed off in FEL4.
  5. Allow for a larger extent of parallel construction and commissioning activity and its associated risks.
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