Planning an Iron Ore Mine: From Exploration Data to Informed Mining Decisions

The process of developing an iron ore mine from exploration data through to informed mining decisions provides an example of a Complex Adaptive System. The detailed composition of an ore body (expressed as a “block model” of regularly spaced rectangular blocks) has to be estimated from initially sparse exploration data, based upon a limited number of drill holes. As planning proceeds, the data may be enriched by appropriately selected infill drilling. Once mining commences, the block model is further enhanced by assay results obtained from the ore as it is mined. Ore blocks have to be selected, and then sequenced with the aim of producing a steady flow of ore having consistent marketable grade, consistent not only in iron content but also in the major contaminants, particularly silica, alumina and phosphorus. Information at each stage of planning and implementation is gathered from a range of natural, technical, economic and financial environments, and interpreted through a dynamic network of interactions between these environments. The process is highly adaptive in as much as fairly complete plans must be made before any mining commences, but these plans will require adjustment in response to steadily increasing knowledge of the ore body, unforeseen technical problems and changes in the financial and economic conditions under which the mine is planned and subsequently operated. Central to the planning process is a block model of the prospect, comprising probabilistic data as to the prospect’s composition. The block model is refined as the project develops, enabling partially informed decisions whose outcomes further enhance the block model. This paper tracks the stages of development of the block model and ore selection and sequencing, from exploration through to production, and in doing so examines the complex adaptive features that are likely to be encountered.