Diesel Fuel Rebate Scheme - is talc a mineral?

Is talc a mineral for the purposes of determining what constitutes 'mining operations' as defined in subsection 164(7) of the Customs Act 1901 ?

Yes. Talc is a mineral for the purposes of determining what constitutes 'mining operations' as defined in subsection 164(7) of the Customs Act.

Raw talc is extracted from the ground using large mining excavator equipment.

When extracted, the raw talc is in the form of large rocks and/or small boulders.

Talc is a soft, white to green material. It has the formula Mg3Si4O10(OH)2. It does not become plastic nor swell when wetted. It is formed deep below the surface by metamorphic processes when igneous rocks, such as granite, intrude magnesium rich sediments. When exposed by erosion, or by mining, it is found in large coherent masses which will not readily break up. Blasting and impact mining are required to separate the talc masses from surrounding rocks. In order to reduce the talc to an ultrafine grainsize, crushing and grinding is required.

'Mining operations' is an eligible activity for the purposes of the diesel fuel rebate scheme. Paragraph (b) of the definition of 'mining operations' in subsection 164(7) of the Customs Act defines that term as meaning 'operations for the recovery of minerals'.

Subsection 164(7) of the Customs Act defines 'minerals' as:

Minerals in any form, whether solid, liquid or gaseous and whether organic or inorganic, except: (a) sand, sandstone, soil, slate, clay (other than bentonite or kaolin), basalt, granite, gravel or water; or (b) limestone (other than agricultural use limestone).

The above definition contains two tests that must be satisfied in order for talc to be considered a mineral for the purposes of the diesel fuel rebate scheme.

The first test is whether talc is a 'mineral' as that term is commonly understood. The Macquarie Dictionary revised 3rd edition, 2001 The Macquarie Library Pty Ltd, NSW defines 'mineral' as being 1. a substance obtained by mining; ore. Talc clearly meets this definition.

The second test is whether talc is excluded from being a mineral by any of the specific exclusions in the definition. Talc is clearly not sand, sandstone, soil, slate, basalt, granite, gravel or limestone. Therefore, talc is a mineral as defined in subsection 164(7) provided it is not clay.

Some mineralogists classify talc as a clay mineral. However, other mineralogists do not support this classification for the following reasons: • Clay minerals commonly consist of hydrous layer silicates of aluminium. Talc does not contain aluminium. • Clay commonly consists of particles of less than 4 microns. Talc on the other hand is found in large, coherent masses. • Clay commonly becomes plastic and swells when wetted. Talc does not. • Clay is usually formed by surface weathering processes. Talc is generally formed deep under the surface by metamorphic processes.

Given the above arguments, it is accepted that talc is not clay. Therefore, talc is a mineral for the purposes of determining what are 'mining operations' as defined in subsection 164(7) of the Customs Act.