malaysian bar to bar lynas? good luck..., page-3

The article said;

Moreover, thorium has an inconceivably long half-life of over 14 billion years, that is, half the atoms in any sample of thorium will decay in that amount of time. Will Lynas Corporation be in existence for as long, to be responsible for the impact of thorium? In this regard, Lynas Corporation, at the very minimum, should provide an environmental bond and obtain insurance coverage for the protection of the community.

ANSWER:
There are several isotopes of radon with varying half lives. Naturally occuring thorium found in rare earth ores decays into radon-220 (also known as thoron). Radon-220 has a half life of only 55 seconds and none of its subsequent decay products are gases. What this means is that any radon released would have decayed within a few minutes and settled close to its source as radioactive dust. This dust then further decays into non-radioactive lead in a matter of hours.

The planned capacity of the Gebeng plant is 22,000 tonnes per year, with thorium content claimed to be 0.16%. This comes to about 35 tonnes of thorium per year. let?s be generous and take it as 100 tonnes. Assuming the unlikely scenario that a whole year?s supply of ore is left lying around exposed in the plant at any one time, we?re looking at less than 5 mg of radon being produced in a whole year. When dispersed into the air, given radon?s very short half life, this is negligible.