Vermiculite

For more than 80 years Vermiculite has been widely used in the industrial, horticultural, agricultural and construction industries. It is the mineralogical name for the substance hydrated, laminar magnesium-aluminium-iron silicate, that to the untrained eye, appears to be mica. It is found in many parts of the world, primarily Australia, Brazil, Zimbabwe, USA, South Africa, Kenya and China.

Vermiculite mines are invariably surface operations where the ore containing vermiculite has to be separated from other minerals and then screened and classified into several common particle sizes. When vermiculite is subjected to heat it expands into pieces that have worm like appearances. This rather unique feature lends itself to its name that is derived from the Latin word for breeding worms, vermiculare. It is caused by the separation of its layers reacting to the fast conversion of water into steam, a feature that lends itself to its commercial use.

The benefits of vermiculite are as follows:
- The balancing of soil temperature fluctuations through its insulation properties
- Its ability to retain air
- It is free from insects, weeds and disease
- If kept dry it does not deteriorate while in storage
- A capacity for high cation-exchange
- Has low alkalinity
- Makes re-wetting easier
- An ability to absorb excess nutrients
- It is non-irritant and non-abrasive
- Has a high water holding ability
- Not a fire hazard nor does it have any known toxicity
- It is sterile and inorganic

Vermiculite uses include the following:
- Acoustic panels
- Refractory insulation
- Open fireplaces
- Fireproofing of pipes and structural steel
- Automotive brake linings
- Floor and roof screeds as well as insulating concrete
- A highly absorbent packing material
- Waste water treatment
- Provision of a smooth base for in-ground swimming pools as an ingredient in Portland cement as a base for swimming pool vinyl liners
- As commercial hand warmers
- Facilitating the incubation of reptile eggs
- Light-weight insulative concrete
- Insulation for AGA cookers
- Ember simulator in gas fireplaces

Vermiculite is a perfect mineral to assist in the germination of seeds as it has very high water holding capacities and aeration properties. These features make it ideal as a medium that has direct contact with seeds.

Although vermiculite is a mineral that has a versatile role to play in industry it has suffered from readily available substitutes, such as perlite, that does a similar job but is cheaper. However, it is still a mineral that has considerable value in today's modern industrial economy, especially in the sense of it being used as a lightweight insulating material in the construction industry.

There are few vermiculite mining operations in the south west Pacific region but there is the potential to develop an economic mine in New South Wales, north of Fifield in the Tottenham area, where there are two large deposits. The NSW deposit of vermiculite was discovered in 1991 at Hillview, near Tottenham. This resource has been published as being 12.5 million tonnes grading at 33 percent vermiculite, along with another deposit at nearby Tigers Creek, that has a reported resource of 4.8 million tonnes grading at 34 percent. The oldest vermiculite mine still operating in Australia is the Mud Tank Mine near Alice Springs in Central Australia. In recent years the Mud Tank Mine has produced around 12,000 tonnes of vermiculite each year.