Outcome:	1. Environment			Question No: 73
Division/Agency:	Supervising Scientist
Topic:	Ranger uranium mine
Hansard Page ECITA:	100

Senator Eggleston asked:
Can I ask one question here in relation to Ranger?  I understood that yellowcake was not radioactive. Where is the radioactivity coming from?

Answer:
Yellowcake is a uranium-bearing chemical compound that is the penultimate stage in processing of uranium ores to produce a pure uranium oxide product.  The uranium oxide product is also sometimes called yellowcake.  The radioactive element in both is uranium.

In addition to containing uranium, naturally-occurring uranium ore also contains other radioactive elements from the radioactive decay series.  These other elements are removed from the ore in the milling process and incorporated into the mine tailings (waste), which is retained at the mine site.

There are a number of different forms of radioactive decay that different elements and isotopes undergo to produce the ionising radiation that is commonly understood as “radioactivity”.  Included amongst these are alpha, beta and gamma radiation.  These different forms of radiation have different penetrating power.

Alpha radiation has low penetrating power, being stopped by a few centimetres of air, a sheet of paper, clothing or the dead outer layer of skin.  Pure uranium, uranium oxide or yellowcake produces predominantly alpha radiation, so although it is radioactive, virtually all of the radiation produced is blocked by any form of container or isolation leading to a mistaken but understandable conclusion that yellowcake is not radioactive.

The mine tailings contain the radioactive impurities from the ore, which also emit alpha radiation in addition to the more penetrating beta and gamma radiation.

At Ranger these tailings wastes, which contain less radioactivity than the original ore, are being returned to the mined out pits for burial after the uranium is extracted.