Coal lithotype classification

It should be pointed out that the lithotype classification for brown coal does not conform to that for black coal. To date, the International Committee for Coal Petrology (ICCP) has not finalized a brown coal lithotype classification however, it is generally agreed that a lithotype classification should be based on macroscopic characteristics that can be determined in open cut faces. This principle has been followed in classifying the Latrobe Valley coals according to a system developed and used by the State Electricity Commission of Victoria (SECV) (25). 

Coal lithotypes are megascopically recognizable components of coal. Several nomenclatures have been used to identify the lithotypes [see Damberger et al. (54) for a review of several common classifications]. Coal lithotypes have fairly distinct maceral compositions, which originate from different combinations of plant materials and evolve along somewhat different paths during coalification. 

Figure 3. Macropetrographical classification of 15 brown coal lithotypes from the Rhenish area. (Reproduced with permission from Ref. 2. Copyright 1981, Schriftleitung Braunkohle.)...

Victorian brown coal occurs in five major lithotypes distinguishable by color index and petrography. Advantage has been taken of a rare 100 m continuous core to compare and contrast chemical variations occurring as a function of lithotype classification. For many parameters there is a much greater contrast between the different lithotypes than there is across the depth profile of (nearly) identical lithotypes. Molecular parameters, such as the distributions of hydrocarbons, fatty acids, triterpenoids and pertrifluoroacetic acid oxidation products, together with gross structural parameters derived from IR and C-NMR spectroscopic data, Rock-Eval and elemental analyses and the yields of specific extractable fractions are compared. 

Table I. Lithotype Classification Typical Characteristics of Air-Dried Coal...

In on effort to establish the mechanism of coal flotation and thus establish the basis for an anthracite lithotype separation, some physical and chemical parameters for anthracite lithotype differentiation were determined. The electrokinetic properties were determined by streaming potential methods. Results indicated a difference in the characteristics of the lithotypes. Other physical and chemical analyses of the lithotypes were mode to establish parameters for further differentiation. Electron-microprobe x-ray, x-ray diffraction, x-ray fluorescent, infrared, and density analyses were made. Chemical analyses included proximate, ultimate, and sulfur measurements. The classification system used was a modification of the Stopes system for classifying lithotypes for humic coals. 

Using polished pellets 1 inch in diameter, a microscopic particle classification analysis for lithotypes, developed for this research by the authors (I), was made of the various coals. Only vitrain, durain, and fusain were counted. Results are presented in Table IV. Standard visual parameters were used for particle identification. An analysis of this type, although not necessarily conclusive, is important for a relative comparison. Results of a check between... 

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