Douglas B. Chambers, Leo M. Lowe & Ronald H. Stager

Table 3: Estimated long term radon emissions from uranium tailings sites after decommissioning

	Mill location/ name	Ore grade (%U)	Area (ha)	Flux (Bq m^-2s^-1)	Emission rate^b (MBq s^-1)	Refs.	Comments

Australia	Ranger	0.30	63	0	0	10, 11	Long-term flux based on 12 m rock cover

	Olympic Dam	0.051	720	0.2	1.44	12, 13	Flux estimated for proposed rehabilitation plan

Canada	Key Lake^a	13	24	0	0	2	Tailings water-saturated and covered

	Rabbit Lake	1.9	14	0	0	2	Tailings water-saturated and covered

	Cluff Lake	0.51	29	7	2.03	14	Based on current decommissioning strategy (thickened tailings and 1 m cover)

Namibia	Rössing	0.0298	750	1.2	9.00	15	Based on measurements on uncovered tailings; no reduction for future decommissioning assumed

Niger	Akouta	0.43	50	0.10	0.050	16	Flux estimated for future covered tailings (above a background flux of about 0.05 Bq m^-2). Ore grades based on mill averages to 1996

	Arlit	0.29	50	0.10	0.050	16

UNSCEAR Model				3		1	Area normalised to 210 tU and 1 ha per GW-year

a. Key lake tailings refers to tailings produced from both Key Lake ore and McArthur River ore to be milled at the Key Lake mill (see text) b. The number of significant figures shown should not be considered indicative of the precision of the estimates.