In this article, the team at Hetherington will explore all facets of diamond mining – from the geological basics about diamonds, through to the future of diamond mining in Australia.
A diamond is pure crystallised carbon. On a global level, diamonds are most commonly clear, though they do have a number of coloured variants, including pink, golden and blue, and even rarer designations including champagne, cognac and violet. Diamond is rarer than most other minerals, which along with its qualities is one of the key determinants of its value.
Diamonds form up to 150 to 200 kilometres underground where the extreme temperatures result in the crystallisation of carbon. Subsequently, they rise with magma towards the surface in ‘pipes’, which may then erode, leaving behind deposits. These deposits vary in quality, though even low quality diamonds have their applications.
As everyone knows, diamonds are common in jewellery, particularly engagement rings. They are therefore the boon of the jewellery trade and mining operations find most of their clientele in this space. However, diamonds also have a number of other applications. Lower class diamonds go to industrial applications that many people may not know about.
Low-grade diamonds may be used for shaping metal alloys that are used within machines. For example, they may be used for incredibly fine, precision tool tips. The ability of diamond to be so fine and precise in its cutting ability is also helpful for electrical and engineering purposes.
Diamonds are also utilised for drilling bits in mineral explorations (including oil, gas and other minerals), being able to withstand and break through materials that would otherwise be rebuffed. They are even used for drilling masonry, cutting roads, and as saw blade tips used in intense applications such as concrete or building stone.
Diamonds are useful for these purposes largely because of their incredible hardness (accordingly, they are measured along the Mohs scale of hardness). They are the hardest mineral on earth found naturally, and boast a melting point of 4000 degrees Celsius, which is two and a half times the melting point of steel.
Diamonds are also broken down as compounds or powders which are then useful for graceful and fine finishing, the sort that may appear or be necessary within jewel bearings, airplane engines and ceramics.
Diamonds are mined around the world. Many countries in Africa have large-scale diamond deposits, including South Africa, Botswana, Congo, Zimbabwe, Namibia and Angola. India historically produced many diamonds but outside of Africa the main countries in the present day are Canada, Russia and Australia.
The first Australian diamonds were located in New South Wales mid-way through the 19th century. However, as exploration techniques became more sophisticated, varied diamond pipes were located in Ellendale and Argyle in the late 1970s, in the Kimberley region of Western Australia.
Exploration methods had to adapt to the terrain; miners were lowered off of river mouths to explore for diamonds in the north-east Kimberley in shark cages to protect them from crocodiles. The persistent search soon paid off and uncovered the ‘Argyle pipe’, which turned out to the world’s premier diamond deposit (for a long time producing a third of supply). Furthermore, the same mine produced 90 per cent of the world’s supply of pink diamonds.
Diamond mining requires significant excavation and displacement of ore, with up to 250 tonnes needing to be excavated on average to produce one pure, jewellery-grade 200mg diamond. In time, exploration became more sophisticated and started to embrace creek sediment sampling, X-ray technology, helicopter-surveying and other methods, allowing for greater return on investment.
With the excavation required, mining operations may be either open-cut or subterranean, and the Argyle operation transitioned to block cave methods in 2013. The excavated ore is generally crushed and then washed in drums prior to being fed down vibrating conveyers which assist in separating the diamonds.
Subsequently, before use, diamonds must undergo processing. However, diamonds are not always processed by the mining corporation. They may be sold rough or uncut.
In a historically significant turn of events, the Rio Tinto Argyle mine – which had produced over 865 million carats of rough diamonds over 37 tears – ceased operations in November 2020. However, there are many plans afoot to recommence large-scale diamond mining in Australia, for example in the Ellendale site in the Kimberley.
Similarly, many mining corporations are undertaking significant exploration operations to uncover Australia’s next big diamond find. There is at present a significant opportunity to establish status as Australia’s key diamond mine and to support the world’s demand.
The mining lawyers and environmental consultants at Hetherington have supported many clients through the legal aspects of mining, including tenement compliance, mining approval, mining development consent, tenement management, mine work health and safety, environmental compliance, establishing a program of work or mining operation plan, and more.
With three offices spread across the country, our mining law firm is positioned to ensure the successful operation of your mining operations through sound legal advice and representation, whether you are opening Australia’s next large-scale diamond mine or mining for many of the other natural resources our wonderful country has to offer.