Abstract: A process is described for maintaining the proportions of each coal in a coal blend at a desired level. The process involves(1) making a spectral analysis, preferably by infrared spectrometry, of at least one sample of the coal blend, the sample having known desired proportions of each coal,(2) making a spectral analysis of the coal blend sample of unknown proportions of each coal,(3) comparing the spectral analyses of steps (1) and (2), and(4) upon noting a significant difference between the spectral analyses of steps (1) and (2), making adjustments to achieve a final coal blend having proportions of each coal closer to those of the blend of known desired proportions of each coal. The relationship of the aromatic to aliphatic groupings is preferably determined by spectral analysis of each coal sample.This process is particularly useful on-line in the production of blast furnace coke of high strength and high stability.