X-ray radiation monitor for measuring solids content in fluid fine tailings

The extraction of bitumen from oil sands produces fluid fine tailings (FFT) consisting mainly of water, sands, clay, and residual bitumen. Generally, devices with radioactive sources are used to measure the variation of FFT density or solids concentration inline, but to date there is no suitable device for in situ monitoring in tailings storage facilities such as large tailings ponds. In this study, an alternative method using high-resolution spectrometry based on a low radiation intensity source and a cadmium telluride (CdTe) detector was used to measure the solids content in tailings samples based on X-ray attenuation. The radiation source used in the experiment was a 1 μCi ¹³³ Ba. GEANT4, a Monte Carlo-based simulation code that calculates the transmission of radiation through matter, was used to simulate the results of this study and build calibration curves that can determine the solids content concentration based on measured sample composition. Experiments and simulations were performed on various concentrations of both actual FFT samples from tailings facilities and kaolin as a model material. Good agreement between the experimental and simulation results was observed, paving the way for a potential real-time solids content measurement system that could be deployed over large areas to measure the settling of FFT in tailings ponds.