Physical parameters determination for gibbsite – bearing marl, Abu – Thor area, Southwestern, Sinai, Egypt

For the sake of determination of some physical factors for gibbsite – bearing marl, at the area under consideration, a cylindrical tube of length 60 cm and diameter 6 cm was used. This tube contains ten CR-39 detectors of area 1 cm*1 cm fixed on the inner side of the tube in mutual positions of fixed interval distance 5 cm for each. The measured radon gas concentrations ranged from 1027.87 ± 93.32 Bq/m3 to 1712.39 ± 126.19 Bq/m3, the exhalation rate ranged from 3.39E-5 ± 3.08E-6 to 4.66E-5 ± 3.00E-6 mBq/m2s−1. By using the measured value of porosity which is (49.19%), the measured diffusion coefficient was calculated, it ranged from 3.26 E-3 (m2 s−1) to 5.77E-8 (m2s−1) and the diffusion length ranged from 3.63 m to 56.19 m, these values were used to determine the depth of the top of radioactive layer, the obtained results was found to be 1.683 m.