Design for radiation protection in the mining of high grade uranium ore

The estimation of external radiation exposures is an important aid in developing radiation protection plans at the design stage of a uranium mine/mill facility, particularly when high grade ore is involved. The principle factors which should be evaluated in the calculation of external exposures are the dose rates at contact with various types of sources, the distances between the source(s) and the work stations, the affect of any proposed shielding and the selection of exposure times workers spend at the various work stations. The last factor is a particularly important consideration for workers who may be exposed to gamma fields from unshielded high grade sources, such as geologists and surveyors, and mill staff who carry out cleanup or maintenance operations