Shales coaly

If the mineral matter in the coal exceeds about 40%, then the material is referred to as a coaly or carbonaceous shale. If the mineral matter is a finely divided clay, well dispersed in the coal, then the material may be described as a stony coal or bone coal. 

For the samples of high C concentrations, obtained by a chemical enrichment of coaly shales, the technique was developed, which uses in addition the CK analytical line intensity to correct interelernent effects. The application of this correction allowed to reduce errors in determining the studied element concentrations up to an acceptable level. The cai bon content was determined over the range 1 to 100 %. 

Coaly Shale Shale, Black, Rough, Blocky Coal 22.0 77.4... 

Nearly all the coals examined are relatively high in ash. Only two of the samples from the Terrace Ridge area contain less than 20% ash, on a moisture-free basis. Most of the remaining samples from this area range from impure coal to coaly shale. Most of the mineral matter is finely divided (dehydrated) clay, silica, and pyrrhotite. This is an important point since the proximate and ultimate analyses for material that deviates so widely from what is normally considered coal cannot be considered particularly reliable for comparison pur-... 

Clayton J. L. (1993) Composition of crude oils generated from coals and coaly organic matter in shales. In Hydrocarbons from Coal, AAPG Studies in Geology 38 (eds. B. E. Law and D. D. Rice), American Association of Petroleum Geologists, Tulsa, OK, pp. 185-201. 

Also supporting a post-depositional origin for arsenic are geochemical data on shales and sandstones adjacent to As-rich coal beds (J. Hatch and M. Goldhaber, unpublished data). These rocks are low in arsenic and associated elements. The mean arsenic content of sandstones adjacent to the coal beds is 9 ppm (n=20) and the median 5.5 ppm. The mean arsenic content for adjacent non-coaly shales is 20 ppm (n=29), and the median arsenic content is 12 ppm. For comparison, the average arsenic content of sandstones is 1 ppm and shales is 13 ppm (Turekian and Wedepohl, 1961). If as is typical arsenic is transported to the depositional site adsorbed on particle surfaces, it is likely that the adjacent rocks (particularly shales) would be enriched, reflecting the sedimentary erosional source of the arsenic. 

It is likely that a large proportion of the natural gas in these shales evolves from low-rank maturation of the coaly kerogen. 

Characterization of the mineral matter in coal is important for a number of reasons. Because of the way coal must be mined, the mine-run product always includes some rock material other than coal, thereby contributing mineral matter to the mine product. Miners of a thin seam usually have to remove some roof and floor strata. Irregular bodies of roof shale or other rocks frequently occur within coal seams and inevitably become part of the mine product. Some coal seams grade upwards to shale coal or coaly shales so that there is no clear-cut boundary between coal and the roof rocks. In addition, many coal seams contain one or more mineral partings of various thickness so that miners must include these in the mine product. It is best for mining and sales purposes if the amounts, types, and characteristics of these rock materials be known prior to mining in order to properly design the mine and preparation plant. 

III Coals, coaly shales, deltas vascular land-plants 0.7-1.0 >0.1 < 0.02 ... 

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