Thanks guys for the information.Jukes, Short half life doesn't...

Thanks guys for the information.

Jukes, Short half life doesn't neccessarily mean less dangerous, in fact short half life means if you get a dose, you get a lot of activity delivered very quickly. You really shouldn't be so disrespectful of nasty little alpha emitters like radon gas.

"Nearly a decade has passed since the fourth in a series of studies called Biological Effects of Ionizing Radiation (BEIR) assessed the risks posed by exposure to radon and other alpha emitters in 1988. Radon, a gas emitted into homes from the soil, from water and from building materials, becomes trapped in homes. Its radioactive daughters, the progeny of radioactive decay, are inhaled into human lungs, where further decay results in the exposure of lung cells to densely ionizing alpha particles. On the basis of considerable experience gained by studying health effects in uranium and other miners who worked in radon-rich environments, the radioactive radon progeny were identified as a cause of lung cancer. It has not been clear whether radon poses a similar risk of causing lung cancer in men, women, and children exposed at generally lower levels found in homes, but homeowners are concerned about this potential risk, and the Environmental Protection Agency (EPA) suggests "action levels," concentrations to which citizens are encouraged to reduce their levels of exposure. "

From preface: Health Effects Of Exposure To Radon
BEIR VI (1999)Committee on Health Risks of Exposure to Radon (BEIR VI)Board on Radiation Effects Research Commission on Life Sciences National Research Council

from here, http://books.nap.edu/html/beir6/

some people should take it seriously, especially the 15-20,000 people who the above suggest die each year in the US from exposure to the progeny of radon gas (mostly polonium that does the damage).

Polonium 210 is 250,000 times more toxic than hydrogen cyanide. It might take less than one millionth of a gram breathed in to kill you.

http://en.wikipedia.org/wiki/Polonium#Acute_effects

Kashga,You talk as if Granite is some sort of immutable force. What was it that changed the granite rock of the Yilgarn into 200 plus metre thicknesses of Saprolite and Kaolinite topped with quartzitic sands and concretionary ferruginous duricrust, that make up most of the Avon and Swan Catchment. No Granites on the Swan Coastal plain. Only real exposure of the waters recieved by the Swan and Avon to granites would be via the Darling Scarp and limited outcrops inland. Most if not all the aquifers sit on top of, not in the Granites of the Yilgarn craton of the Swan Catchment area. The Granite forms the aquatard.

With the increased exposure of the granite through greatly expanded fractures, there are going to be alot of alkaline feldspars and silcates available for dissolution. On the way to turning to clay!
The circulating volumes would be quite large in the final scaled up plant I would guess.

HerbieJohnster66, thanks for your response, that is quite a substantial volume of rock fractured. Sounds like there are still quite a few unknowns in the hydrogeology of the project. As you would expect of such a cutting edge project. Coooooooooooooool, I mean Hooooooooooooot stuff!

Cheers

onepot