Australia’s Identified Mineral Resources
The National Classification System for Identified Mineral Resources has been used by the Australian Government since 1975 for classifying mineral resources for regional and national assessments. It provides a long-term view on what is likely to be available for mining.
The National Classification System uses two general criteria for classifying Australia’s national inventory of mineral resources:
- the geological certainty of the existence of the mineral resource, and
- the economic feasibility of its extraction over the long term.
The National Classification System (See Appendix 2) uses reports on mineral resources published by companies using the JORC Code (or equivalent foreign codes) and, to a lesser extent, confidential information, to compile national totals for the resource classification categories set out in Table 3. Both the National Classification System and the JORC Code are based on the McKelvey resource classification system used by the USGS. Thus Australia’s national system is compatible with the JORC Code and remains comparable to the USGS system, as published in the annual USGS Mineral Commodity Summaries.
Economic Demonstrated Resources (EDR) is the category used for the national totals of economic resources and provides a basis for meaningful comparisons of Australia’s economic resources with those of other nations. The Commodity Summaries section provides a snapshot of key facts and figures for the 35 mineral commodities covered in AIMR 2021, including EDR, Ore Reserves, production, rises and falls and world rankings.
Estimating the total amount of each mineral commodity likely to be available for mining over the long term (EDR) is not a precise science. The long-term perspectives presented herein take account of the following:
- Ore Reserves reported in compliance with the JORC Code (or equivalent foreign codes) will all be mined, but they only provide a short-term view on what is likely to be available for mining.
- Most current Measured and Indicated Resources reported in compliance with the JORC Code are also likely to be mined.
- Some current Inferred Resources will be transferred to Measured and Indicated Resources and Ore Reserves.
- New discoveries will add to the resource inventory.
In addition, some resources that, all being equal, would normally be considered EDR are not accessible because of environmental, legal or military land-use restrictions. Thus Table 3 also lists Accessible Economic Demonstrated Resources (AEDR). Of the 35 mineral commodities assessed in this publication, only black coal, brown coal, gold, mineral sands, platinum group elements and uranium have EDR that is considered inaccessible.
Over time, all of Australia’s current EDR of gold, silver, tin, zinc or any number of other commodities will be mined. At first glance, this statement might seem somewhat paradoxical because not every deposit that contributes to the national EDR will have all of that individual EDR brought into production. Indeed, some deposits currently contributing to EDR will never produce any metal. However, the National Classification System is not designed to be used for individual mine assessments. Instead, it is a way of estimating regional and national totals. So, from an aggregated point of view, it is a reasonable proposition that, eventually, all of the current EDR (and more) will be mined. Twenty years ago, gold for example, had an EDR of 4,959 t; since 2000, Australian mines have produced 5,710 t of gold.
Australia is yet to run out of EDR because, to use JORC Code terminology, as individual Ore Reserves are depleted, Measured and Indicated Resources are reassessed into Proved and Probable categories, Inferred Resources are worked on to bring them to Measured and Indicated status and new drilling at existing mines as well as new greenfield discoveries add to the resource inventory. In addition, extractive technologies improve over time and if a commodity becomes rare then the laws of supply and demand result in previously subeconomic deposits becoming profitable. Thus EDR fundamentally differs from Ore Reserves under the JORC Code because it is not meant to provide a picture of what is currently commercial to mine but rather an outlook on what is likely to be available for mining over the long term, i.e., of opportunity for supply at regional and national scales.
Table 3. Australia's Identified Mineral Resources as at December 2020.
|Demonstrated Resources||Inferred Resources2||Accessible EDR3||Mine Production4||Economic Resources5||Mine Production6|
|Contained iron||Mt Fe||27,553||1,781||426||40,549||27,553||571||87,000||1,500|
|Contained P2O5||Mt P2O5||178||91||0||388||178||n.a.||n.a.||n.a.|
|In situ||Mt K2O||42.5||260.6||0||1073.4||42.5||0||n.a.||n.a.|
|Rare Earths30||Mt oxide||4.20||4.24||34.74||23.49||4.20||0.02031||116||0.24|
t = tonne; kt = kilotonnes (1,000 t); Mt = million tonnes (1,000,000 t); Mc = million carats (1,000,000 carats); GL = gigalitre (1,000,000,000 L); n.a. = not available; PGE = platinum group elements (platinum, palladium, osmium, iridium, ruthenium, rhodium).
Where an element symbol follows the unit it refers to contained metal content.
Trends in EDR
Australia’s EDR of the following mineral commodities increased significantly (up 5% or more) during 2020: antimony, cobalt, lithium, molybdenum, platinum group elements, potash, scandium, tantalum, tungsten uranium and vanadium (Table 4). Only the EDR of in situ brown coal decreased significantly (down 5% or more) in 2020. All other mineral EDR stayed within +/-5% of the previous year’s estimates (Table 4).
Australia’s EDR of a range of mineral commodities have undergone significant and sometimes dramatic changes since Geoscience Australia, and predecessor organisations, began keeping systematic records more than 40 years ago. These changes can be attributed to one, or a combination, of the following factors:
- Increases in resources resulting from discoveries of new deposits and delineation of extensions at known deposits.
- Depletion of resources as a result of mine production.
- Advances in mining and metallurgical technologies, e.g. carbon-based processing technologies for gold have enabled economic extraction from low-grade deposits that were previously uneconomic.
- Adoption of the JORC Code for resource classification and reporting by the Australian minerals industry and the subsequent impacts on re-estimation of Ore Reserves and Mineral Resources to comply with the requirements of the JORC Code. The impacts of the JORC Code on EDR occurred at differing times for each of the major commodities.
- Significant changes in the prices of mineral commodities driven largely by both escalating and cooling demand from China over the past two decades.
Table 4. Changes in Australia's EDR from 2019 to 2020.
|Contained iron||Mt Fe||24,508||27,553||12%|
|Contained phosphate||Mt P2O5||178||178||0%|
|Rare Earths1||Mt oxide||4.03||4.20||4%|
t = tonne; kt = kilotonnes (1,000 t); Mt = million tonnes (1,000,000 t); Mc = million carats (1,000,000 carats); PGE = platinum group elements (platinum, palladium, osmium, iridium, ruthenium, rhodium).
Where an element symbol follows the unit it refers to contained metal content.
EDR = Economic Demonstrated Resources.
Geographical distribution of EDR
Most bauxite EDR are attributable to Queensland and Western Australia (Figure 2) where the giant deposits in Cape York and the Darling Range, respectively, dominate. Similarly, Australia’s enormous iron ore EDR are geographically concentrated in the Pilbara region of Western Australia. Western Australia also holds almost all of nickel and diamond EDR, though the latter is mostly attributable to the Argyle mine which closed in November 2020. Manganese ore EDR are found in Western Australia and the Northern Territory. On the other side of the country, almost all black coal EDR are located in Queensland and New South Wales (Figure 2). Gold, silver, lead, zinc, copper, uranium and mineral sands are dispersed across the country (Figure 2).