The decision making check-list and hierarchy of information for process and plant design is generally wide-ranging and complex._x000D_
The nature of grades, mineralisation and ore types in an ore body, its mine development sequence, and the body of results from metallurgical and physical test work present complex and competing influences on flowsheet development, values for design, equipment selection, plant efficiencies and operating strategy. The challenge is how to manage all these variables, to understand their impacts on performance, and how best to provide a cost-effective plant design and robust process that meets daily/weekly/monthly operating objectives._x000D_
Throughput, production and grade or product specifications need to be met._x000D_
The ore body is not average; its range of metallurgical and physical characteristics may be moderately to highly variable._x000D_
This paper assesses some of the key competing influences and conflicting issues in design and equipment selection, and their effect on production and performance expectations._x000D_
FORMAL CITATION:McLean, E, 2011._x000D_
We're metallurgists, not magicians!', in Proceedings MetPlant 2011, pp 374-390 (The Australasian Institute of Mining and Metallurgy: Melbourne).