MIDDLE DEVONIAN COAL IN ILLINOIS 



TABLE 2 - CHEMICAL ANALYSIS OF PORTION OF SAMPLE NO. 1 

 (Lab No. C. - 15 776) 





As 

 received 



Moisture 

 free 



Moisture 



and 

 ash free 



Proximate analysis 



Moisture 

 Ash 



.9 

 32.0 



32.3 





Ultimate analysis 

 Total 



Hydrogen 



Carbon 



Nitrogen 



Oxygen 



Sulfur 



Ash 



4.0 



51.7 



.8 



4.3 



7.2 



32.0 



100.0 



4.0 



52.2 



.8 



3.6 



7.2 



32.2 



100.0 



5.9 



77.0 



1.2 



5.2 



10.7 



100.0 



Low— temperature 

 ashing 



Mineral 

 matter 



43.0 







The reflectance of vitrinite grains in oil immersion from Sample no. 1 var- 

 ies between 0.60 and 0.85 percent. The larger vitrinite lenses of more than approxi- 

 mately 100 |jl in diameter have a 0.04 to 0.06 percent higher reflectance than the 

 smaller ones. The average reflectance of all vitrinite macerals measured was cal- 

 culated at R o =0.74 percent, which corresponds to vitrinite reflectance from coal 

 with 14,000 to 14,700 Btu/lb on a moist, mineral matter-free basis (Illinois State 

 Geological Survey unpublished data — high volatile A coal). 



All Pennsylvanian coals in central Illinois have a somewhat lower rank 

 (high volatile C). The gradients of increase of calorific or reflectance values 

 by depth, however, cannot be determined with satisfactory accuracy because of the 

 lack of other samples in the area of these three boreholes. 



The spores in this Devonian coal are very dark. Two kinds could be dis- 

 tinguished: the brownish gray, very dark large spores that have a reflectance (R ) 

 between 0.07 and 0.13 percent (average of 0.11 percent) and the somewhat lighter 

 and usually smaller spores with R between 0.20 and 0.27 percent (average of 0.24 

 percent). The difference of 0.5 to 0.6 percent between the spores and the vitri- 

 nite of this coal is typical for high volatile bituminous coals. In medium and low 

 volatile bituminous coals, spores have only a slightly lower reflectance than vitri- 

 nite s . 



Several small pieces of coal (a total of 9 . 8 g) that had broken off the core 

 of Sample no. 1 were analyzed and submitted for low-temperature ashing to de- 

 termine the minerals in the coal (H. J. Gluskoter, 1965) (table 2). 



Of the 7.2 percent sulphur, probably 5 to 6 percent is pyritic sulphur (py- 

 rite equivalent 9 to 1 1 percent), which must be added to the ash for total mineral 

 matter value. The difference between the approximately 38 percent mineral matter 

 thus calculated and the 43 percent mineral matter measured by low -temperature 

 ashing is primarily due to the loss of CO2 (carbonates.) and SO2 (pyrite) during the 



