Abstract: Diffusion process is the main factor that leads to the migration and exhalation of radon in uranium ore. Taking into account the fact that the hazard exists in underground uranium mine and field sampling are rather difficult, it is not conducive to do the laboratory test. In order to solve the above problems, based on the similarity theory, a kind of typical granite was taken as the prototypical model, and the quartz sand, uranium tailings, cement, fine iron powder and silicon powder as the raw materials, three cylindrical uranium-like rock samples with different material ratios were prepared, and the physical and mechanical parameters were then measured. In addition, these samples were sealed in different ways and the corresponding cumulative radon concentrations were measured by closed chamber method. The formula for calculating the diffusion performance of radon is deduced, and the radon diffusion length and diffusion coefficient of the prototype and the samples were calculated. The results showed that the mean similarity ratios of the particle density, compressive strength, tensile strength, cohesion and internal friction angle of the granite rock and quasi-uranium ore were respectively 1.09 ∶1, 3.93 ∶1, 4.28 ∶1, 3.47 ∶1 and 1.00 ∶1, the diffusion coefficient of granite prototype was 0.146×10^-6 m²·s^-1, the diffusion coefficient of quasi-uranium ore was between 0.114×10^-6 m²·s^-1 and 0.594×10^-6 m²·s^-1, and the similarity ratio was between 0.25∶1 and 1.28∶1. Therefore, the third sample of similar materials to some extent can be used to simulate the granite-type uranium rock and can meet the needs of laboratory experiments.

Key words: quasi-uranium ore, similarity theory, radon, closed chamber method, diffusion coefficient