Asbestos is the common name for a variety of naturally occurring silicate minerals that are fibrous in structure. This mineral occurs in many parts of the world, the main sites of commercial asbestos mining and production are:
- Canada,
- the Soviet Union, and;
- Southern Africa.
Asbestos containing rock is crushed and milled at the mining site to produce raw asbestos of various grades.
There are six types of asbestos which fall into two category’s of fibre type. The two asbestos fibre types are Serpentine (curly, wavy fibres) and Amphibole (needle like fibres).
Of the six types of asbestos the three most commercially utilised are:
- Chrysotile (White – Serpentine),
- Amosite (Brown – Amphibole), and;
- Crocidolite (Blue – Amphibole).
The other three types of asbestos are amphibole fibre types and are far less common. These are:
- Anthophylite,
- Tremolite, and;
- Actinolite.
Asbestos strands can be split into smaller and thinner fibres during disturbance. Asbestos mined ore will initially divide into visible strands, fibre bundles, and individual fibres.
This splitting can continue on to minute levels of microscopic size. This process is unique to asbestos and is why airborne asbestos is such a problem.
Asbestos fibres can become so small that they remain airborne longer and pass undetected by the respiratory dust defences.
Asbestos would be a great building product were it not for the huge health risks. It has a high resistance to heat and many chemicals and was the building material of choice in the 1960's to the mid '70's in the UK - before the potentially deadly properties of asbestos were known.
Asbestos fibre is mechanically strong and highly resistant to heat and chemical attack. Because of its fibrous nature asbestos fibre can be woven into fabrics and used as reinforcement for cement and plastics.
Asbestos was extensively used as a building material in the UK from the 1950s through to the mid-1980s. It was used for a variety of purposes and was ideal for fireproofing and insulation. Any building built before 2000 (houses, factories, offices, schools, hospitals etc) can contain asbestos.
During this time asbestos was used for a number of jobs such as; floor tiles, pipe lagging, textured paints (Artex), internal partitions, central heating systems, roofs, gutters, rainwater downpipes, cement cladding, fire protection to structural steelwork, fuse boxes, bitumen products and many, many more.
Asbestos materials in good condition are safe unless asbestos fibres become airborne, which happens when materials are damaged.