An analysis of historic production trends in Australian base metal mining

The base metal mining sector, including copper, lead–zinc–silver and nickel, has been a prominent and critical feature of the Australian minerals industry. The various mines and fields have been producers of world significance, including Broken Hill, Mt Isa, Mt Lyell, Olympic Dam, Cobar and Kambalda. The long-term production trends in the base metal sector governing these historic fields remain relatively undocumented. This includes trends in ore grades, mining technique (open cut versus underground), solid wastes produced (tailings and waste rock), technology (e.g., milling) and known economic resources. This paper presents these results for the Australian base metals sector — arguably the first such systematic compilation undertaken. A historical overview is discussed for each major commodity to outline the principal developments and changes for that commodity, followed by the presentation of mining and milling trends. Overall, the key trends are declining ore grades versus increasing metal production and ore milled, and increased open cut mining and associated waste rock (though this latter aspect remains significantly under-reported). The extent of known economic resources has steadily increased for all commodities analysed, principally due to the inclusion of lower grade ores and/or difficult to treat ores (such as nickel laterites) or new deposit discoveries. Based on present mine plans and proposals, future metal production will increasingly shift towards lower ore grades and larger open cut mines to maintain production levels. There are sufficient known economic resources for about three decades or more, providing a basis to sustain the existing base metal industry but beyond this timeframe is difficult to predict. These trends point to the need to accurately report complete data on base metal mining and milling as key inputs into quantifying mineral resource trends as well as the environmental aspects of “sustainable mining”.