Abstract

BATISTA-RODRIGUEZ, J.A.  and  LOPEZ-SAUCEDO, F.J.. Preliminary assessment of coal blend quality combining gamma-ray spectrometry and magnetic susceptibility: A case study of the Sabinas Basin, Mexico. J. S. Afr. Inst. Min. Metall. [online]. 2022, vol.122, n.4, pp.201-212. ISSN 2411-9717.  https://doi.org/10.17159/2411-9717/1418/2022.

A new methodology is proposed for the preliminary assessment of coal blend quality, which combines gamma-ray spectrometry and magnetic susceptibility measurements. This methodology does not replace the conventional methods of assessing coal quality, but can help to control the quality of the coal blending process, as well as reduce the amount of proximate analysis required and the determinations of calorific value and total sulphur. The methodology includes five steps. First, both geophysical measurements are made with handheld equipment. The samples with magnetic susceptibility < 1 x 10-3 SI are then separated. From these samples, those with total gamma intensity < 20 nGy/h are separated. These samples have a higher calorific value and lower ash and moisture content. To separate the samples of better quality and with lower total sulphur content, in step four the samples with total gamma intensity > 20 nGy/h are separated from those with magnetic susceptibility < 1 x 10-3 SI. This last group includes samples that will cause less total sulphur-related environmental pollution. In the final step, the quality of both radioactive sample groups is corroborated from the calorific value measurement and ash, moisture, and total sulphur contents in at least 10% of all coal blend samples from both groups. In this study, more than 1000 samples were analysed with this new methodology, and the results are remarkably similar to the ASTM classification of the Sabinas Basin coals.

Keywords : coal blend quality; gamma-ray spectrometry; magnetic susceptibility; Sabinas Basin.

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