Vermiculite is the mineralogical name given to hydrated laminar magnesium-aluminum-ironsilicate which resembles mica in appearance. All vermiculite ores contain a range of other minerals that were formed along with the vermiculite in the rock. Vermiculite ores from some sources have been found to contain asbestos minerals but asbestos is not intrinsic to vermiculite and only a few ore bodies have been found to contain more than tiny trace amounts.
Vermiculite mines are surface operations where ore is separated from other minerals, and then screened or classified into several basic particle sizes. Vermiculite is found in various parts of the world. Locations of the predominant commercial mines are in Australia, Brazil, China, Kenya, South Africa, USA and Zimbabwe.When subjected to heat, vermiculite has the unusual property of exfoliating or expanding into worm-like pieces (the name vermiculite is derived from the Latin 'vermiculare' - to breed worms). This characteristic of exfoliation, the basis for commercial use of the mineral, is the result of the mechanical separation of the layers by the rapid conversion of contained water to steam. The increase in bulk volume of commercial grades is 8 to 12 times, but individual flakes may exfoliate as many as 30 times. There is a color change during expansion that is dependent upon the composition of the vermiculite and furnace temperature.
Where does the asbestos come from and why is it a health concern?
Vermiculite ores often contain a range of other minerals including, in somecases, asbestos. Asbestos is not a major contaminant, and only a few ore deposits
have been found to contain more than trace amounts of asbestos minerals. However,
exposure to airborne asbestos particles has been linked to respiratory ailments including
cancer, and various organizations is concerned about the increased risk to consumers and
workers from use of asbestos-contaminated vermiculite products.
What To Do If You Suspect You Have Been Exposed To Asbestos
Asbestos related illnesses are usually associated with frequent and prolonged exposure to asbestos. The time it takes to develop a disease from exposure to asbestos is usually long - up to decades. However, some steps you can take if you have concerns about exposure to asbestos are:- Talk to your health care provider.
- Avoid or minimize further exposure to any form of asbestos.
- Stop smoking and avoid second hand tobacco smoke and other irritants that could affect your lungs. Exposure to cigarette smoke and asbestos greatly increases your chances of developing lung cancer.