Goethite: A Common Mineral With a Surprising Role in Australia’s Economy

Goethite is a mineral that may not be very familiar to most people, but it has played a significant role in shaping Australia's history, economy, and culture. It is a form of iron oxide-hydroxide that is often found in soil and sedimentary rocks.

It is also the main component of rust and bog iron ore, which are sources of iron for many industries.

Goethite has been used for thousands of years by various civilizations as a pigment for paint, pottery, and textiles.

In Australia, it has been associated with the Aboriginal culture, the mining industry, and the artistic expression of the land.

Goethite and the Aboriginal culture

(Photo : Ed Ram/Getty Images)

Goethite is one of the minerals that the Aboriginal people of Australia have used for their traditional art and ceremonies.

This, along with other iron oxides such as hematite and limonite, produces a range of colors from yellow to red to brown. These colors are often used to depict the earth, the sun, and the blood in Aboriginal paintings, rock art, and body art.

Goethite is also used to make ochre, a natural pigment that is mixed with water, animal fat, or saliva to create a paint or a paste.

Ochre is used for various purposes, such as decorating objects, marking territory, communicating messages, and expressing identity. It is also considered to have spiritual and medicinal properties and is often applied to the body or the ground during rituals and ceremonies.

Goethite is widely distributed across Australia, and different regions have different types and qualities of goethite.

For example, the Kimberley region in Western Australia is known for its vibrant ochres, which are highly valued by the Aboriginal people.

The ochres are collected from various sites, such as caves, cliffs, and riverbeds, and are often traded or exchanged among different groups.

They are also used to create distinctive styles of art, such as the Wandjina figures, which are ancestral beings that are depicted with large eyes and halo-like headdresses.

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Goethite and the Mining Industry

Goethite is also an important mineral for the mining industry, especially for the production of iron and steel. It is often found in iron ore deposits, along with other minerals such as hematite, magnetite, and siderite.

This mineral can have various textures and compositions, which affect its physical and chemical properties and its suitability for different processes.

For example, goethite can have a hard and vitreous texture, or a soft and ochreous texture, or a mixture of both.

It can also contain impurities such as aluminum, silicon, phosphorus, and sulfur, which can influence its reactivity and quality.

Australia is one of the world's largest producers and exporters of iron ore, and goethite is a major component of Australian iron ore.

According to the CSIRO, Australian iron ore is becoming increasingly goethitic, due to the depletion of high-grade hematite ore and the weathering of existing ore bodies.

This poses a challenge for the mining industry, as goethite ore types can have negative impacts on the various stages of the iron ore value chain, such as mining, beneficiation, agglomeration, and blast furnace.

For instance, goethite ore types can have lower iron content, higher moisture content, lower density, lower hardness, lower magnetic susceptibility, and higher reactivity than hematite ore types.

These characteristics can affect the efficiency, quality, and cost of iron ore production and processing

However, goethitic ore types can also present opportunities for the mining industry, if they are properly understood and managed.

The CSIRO has developed a textural classification scheme to identify and characterize different types of goethite in iron ore and to evaluate their effects on the iron ore value chain.

The textural classification scheme can help the mining industry optimize its production processes, improve its product quality, and reduce its environmental impact.

For example, the textural classification scheme can help the mining industry select the best ore types for blending, adjust the grinding and separation parameters, enhance the sintering and pelletizing performance, and reduce the fuel consumption and slag formation in the blast furnace

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