Nickel mining in Australia uses both surface and underground mining techniques to extract laterite and sulphide ores of different nickel grades. Nickel mining products for export and local use contribute to the Australian economy. The past decade has seen a rise  in the prominence of nickel mining stocks due to electric vehicles. The Australian nickel sector grew over the past decades and this happened due the discovery of laterite ores in the late 1990s. Australia recorded the world’s largest economic demonstrated resources of nickel. Nickel reserves of 40 and 120 years in nickel sulphide ores and all other nickel ores were recorded. Economic statistics gathered in 2019, depicted Australian nickel production decline relative to 2018. Australia ranks 5th with Canada at a global production scale and come behind Indonesia, Philippines, Russia  and New Caledonia. The article seeks to highlight what nickel is with regards to where and how it is mined in Australia, and the importance of dust control in nickel mines with emphasis on Global Road Technology dust control solutions. 

What is Nickel and where is it found?

Nickel is a chemical element and a transition metal, which is present in ores occurring as both sulfides and laterites. Its uses are in steel, cast iron alloys, coins, batteries. China is the world’s largest consumer of nickel at about 55%. World population of nickel in mines sat at 2.7 million metric tons in 2019. The major countries in nickel mining include Indonesia, Philippines, Russia, and New Caledonia. Indonesia has the largest reserves of nickel, followed by Australia and Brazil. Nickel reserves have the least remaining life years, but nickel is recyclable. Nickel sulfide deposits are more common in countries such as Russia, Australia, Canada and parts of southern Africa. Most nickel laterite deposits are found in Indonesia, New Caledonia, Brazil and the Philippines as result of formation in humid tropical conditions and active plate collision zones. 

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Where is Nickel mined in Australia?

Historically, nickel produced at the Zeehan field in Tasmania was high grade. The rise in nickel mining is attributed to the Kambalda region in the Eastern Goldfields of Western Australia. Nickel ore grades in the 1960s had 4% nickel but within a decade the nickel ore grade in Australia fell to 2%. Over the last 20 years, low grade laterite or sulphide deposits have posted an average ore grade of about 1.2%. Magmatic nickel-copper sulfide deposits formed due to mafic or ultramafic rocks. Formation began in the earth’s magma saturated in sulfide after interaction with crustal rocks. Sulfides have a small volume of the host rocks. Their major mineralogy has pyrrhotite (Fe7S8), pentlandite ([Fe,Ni]9S8), and chalcopyrite (CuFeS2). Mining activities at Mt Keith and Perseverance have grown nickel sulphide production. New mines in Western Australia and Tasmania have driven nickel production. Smaller operations such as Miitel and Wannaway also drove nickel mining. Nickel production at Murrin Murrin and BHP Billiton’s Ravensthorpe mine. Nickel mining growth trends favor lateritic nickel deposits over to sulphide nickel deposits. 

How is nickel mined?

Nickel ores occur as both sulfides and laterites. Sulfide ores contain copper-iron sulfides and  nickel iron sulfides. These sulfide ores produce high grade nickel. Processing of sulfide ores occurs in reverberatory or flash-smelting furnaces and horizontal convertors. Copper and nickel sulfide separation happen via crystallization, grinding and froth flotation.  Copper and nickel sulfides are further refined. Laterite ores (saprolite) produce ferronickel used in steelmaking. Laterite ores (limonite and smectite) make melting-grade nickel. Processing of saprolite involves drying, calcination and smelting. Limonite and smectite processing involves high temperature acid leaching and refining. Sulfide ore processing involves concentrating, smelting and refining. Different compositions and mineralogy use different methods of extraction. Smelting of saprolite ore takes place because of low iron content.  Leaching and refining of smectite ores happens because of high iron content.  Laterites occur near the surface and surface mining methods extract them. Laterites are complex ores. They consist of three nickel-bearing layers. Limonite and smectite layers which occurs near the surface. The saprolite layer occurs below the limonite and smectite layers. Sulphide ores occur in ore bodies formed from the intrusion of molten magma in the mantle of the earth’s crust. Sulphide ores grow from localized metal rich sulphide ore bodies that solidified under hydrothermal leaching and precipitation. It is for this reason that sulphide ore mining happens underground. The dust generation at nickel mines results from crushing or grinding of ore. By-products such as quartz contribute to the dust particles generated from nickel mining. The small nickel-rich particles are ~7.5 mm diameter. Small, low-density particles are richer in nickel than large and dense particles. Crushing and grinding at the correct intensity produces small particles. These particles are rich in nickel and the larger particles that are lean in nickel. 

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Dust generation and best practice controls

Nickel mining generates inhalable and respirable dust particles from many of its mining processes. Dust suppression solutions in Australia are achieved through use of innovative solutions from Global Road Technology for sulphide and laterite nickel ores. GRT Ore-Loc is utilized for bulk material dust control of stockpiles and nickel ore loads. GRT Ore-Loc is a robust, dust suppression polymer that provides excellent surface coating solutions in all ore and material surface types. Haul routes either from underground or in open cut scenarios can be managed with 2 key products – GRT Haul-Loc and / or GRT Wet Loc. Both have ideal application into minimizing water truck utilization and effectively preventing road dust generation. GRT products can be applied across diverse range of industries and deliver better environmental and safety protection as they are non-toxic and non-hazardous and reduce the damage caused by fugitive dust

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