Geologic ranking

Figure 5. Geologic ranking sheet. This form serves as a general guide for evaluating and recording geologic information on specific sites. See Table II...

High priority sites are those where hazardous materials might accumulate, move readily at shallow depths, or reappear at the surface in concentrated amounts. Low priority sites are those adjacent to lakes, ravines, or on steep slopes and presumed to have been well drained for an extended period. Any large site with known hazardous contents should be evaluated individually and referred to the appropriate agency regardless of its position in the geologic ranking system. 

Seam correlations, measurements of rank and geologic history, interpretation of petroleum (qv) formation with coal deposits, prediction of coke properties, and detection of coal oxidation can be deterrnined from petrographic analysis. Constituents of seams can be observed over considerable distances, permitting the correlation of seam profiles in coal basins. Measurements of vitrinite reflectance within a seam permit mapping of variations in thermal and tectonic histories. Figure 2 indicates the relationship of vitrinite reflectance to maximum temperatures and effective heating time in the seam (11,15). 

Three West Virginia coals were supplied by the West Virgmia Geological Survey (WVGS). The particular coals were chosen on the basis of rank, petrographic composition, and mineral matter content The coals were limited to the bituminous rank since these coals are the most amenable to the NMP solvent extraction process and are mdigenous to the Appalachian region. Some of the coal characteristics are listed in Table 2. 

Bachu S., Bonijoly D., et al. Screening and ranking of sedimentary basins for sequestration of C02 in geological media in response to climate change. 2003 Environmental Geology 44 277-289. 

These rank investigations included not only individual boreholes and shafts but also larger geological cross-sections and whole coal districts, as for instance the Ruhr Basin (18), the Saar Basin (2), and the Basin of Wealden coals in Lower Saxony (28). From such areas rank maps were drawn representing the regional rank changes of one and the same seam. 

Another proof of the importance of temperature is the fact that there is often a strict relationship between the run of isovols and the run of isotherms in deep profiles, both being influenced no doubt by the varying thermal conductivity of the different rocks. The strong influence of temperature on the rank of coal is obvious in the case of contact-metamorphic coals, whose rank increases distinctly when approaching the intrusive body. Apart from these geological observations, all experiments on artificial coalification have shown that temperature is the decisive factor in the coalification process. Thermodynamic and reaction kinetic considerations (9) also support this opinion. 

Geological investigations have shown that undoubtedly temperature has most influence on geochemical coalification. This is proved by such evidence as contact metamorphism of coals, increase of rank with increasing temperature of the earth s crust with depth, increase of rank of the same seam as magma chambers (batholiths) are approached, and relations between the thermal... 

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