Predicting washability using a regression of ash content with controlled rock to coal mix ratio specimen used for calibration

¹ University of British Columbia, Norman B. Keevil Institute of Mining Engineering, 6350 Stores Road, Vancouver, BC V6T 1Z4, Canada
² School of Energy and Mining Engineering, China University of Mining and Technology-Beijing, Beijing 100083, China

^* Corresponding author: yiran.zhang@alumni.ubc.ca

Abstract

Accurate information on coal washability characteristics is crucial for optimizing beneficiation processes. This study investigates the use of dual-energy X-ray transmission (DE-XRT) in predicting ash content and specific gravity (S.G.) by employing a structured calibration approach. A total of 36 coal samples from a British Columbia mine were analyzed using DE-XRT, S.G. measurements, and ash analysis. A controlled calibration method was developed by systematically varying rock-coal (rock-ash forming minerals) ratios to establish reliable DE-XRT response trends. Results demonstrated strong correlations between DE-XRT-derived relative density and rock mix ratios, confirming its capability in estimating coal quality. The generated washability curves closely followed traditional sink-and-float results, particularly at higher ash contents, validating DE-XRT's potential in coal sorting. These findings highlight DE-XRT as a viable tool for real-time coal quality assessment during its beneficiation. Future work should focus on refining calibration techniques and improving detection in extreme density ranges to enhance prediction accuracy and sorting efficiency.