Common Banded Coal

Nonbanded coal consistently fine-granular coal essentially devoid of megascopic layers may be interbedded with common banded coal or form a discrete layer at the top or bottom of the seam, or may compose the entire seam formed from natural accumulations of finely comminuted plant detritus and commonly includes a significant amount and variety of remains of pollen grains, spores, planktonic algae, wax and resin granules, as well as other fragments of plants. 

Classification by type differentiates the coals accdg to the proportion of various plant ingredients and accdg to appearance. Standard types used in US include common banded, splint, cannel and boghead coals. 

Following are the definitions of the above terms Common banded is the common variety of bituminous and subbituminous coals it consists of a sequence of irregularly alternating layers of lenses of a homogeneous blk material having a brilliant vitreous luster a grayish-blk less brilliant striated material usually of silky luster and thin bands or lenses of soft powder and fibrous particles, known as (usain or mineral charcoal. The difference in luster of the bands is greater... 

Attrital coal ground mass or matrix of banded coal in which vitrain and, commonly, fusain layers as well, are embedded or enclosed. 

Banded coal coal that is visibly heterogeneous in composition, being composed of layers of vitrain, attrital coal, and commonly, fusain. 

Vitrain shiny black bands, thicker than 0.5 mm, of subbituminous and higher-rank banded coal attributed to the coalification of relatively large fragments of wood and bark and commonly traversed by many fine cracks oriented normal to the banding. 

Standard types used in US include common banded, splint, cannel and boghead coals. 

Banded coal contains visible bands of vitrain, which is the remains of single large fragments of ancient plants (see the earlier text), as well as bands of fusain, the remains of smaller fragments of ancient plants (see earlier text). Non-banded coal, however, displays a uniform texture which appears to be fine-grained, lacks a brilliant luster, and consists of comminuted, compacted sediments derived from plant detritus. This type of coal is much less common than banded coal in North America. There are two major types of non-banded coal cannel coal and boghead coal (Stach et al., 1982). 

Figure 2. Photomicrographs showing some of the common entities found in Antarctic coals reflected light, X 150 A—Vitrinoia with cracks. B—Bright inerts in a mixture of vitrinoids (gray) and clays (black), C—Semifusinoids preserving cellular structure. D—Clay minerals (black) containing thin vitrinoid bands (gray)...

Comparable infrared (IR) spectra of complex organic solids such as coals (Fig. 7) 23), cherts, kerogens, humic substances and some natural polymers have been presented in various publications. They show a limited number of rather broad bands which are due to well defined chemical groups and can often be interpreted by comparison to less complicated spectra. The signals commonly observed in fossil organic matter are as follows (Robin et al., 1977 21), Tissot Welte, 1978 24), Rouxhet et al., 1980 22>, Friedel Carlson, 1972 25)) ... 

Coal is a rock commonly found in nature. Due to its economical value, a significant number of studies are dedicated to this subject [14], A variety of coals are known and they are made from a combination of fine laminae and thicker bands of different kinds of organic matter, which vary in their proportion in different coals. Therefore, coal is not a uniform macromolecular material but its composition is fairly well understood. Coal main... 

The correlation between the total phase enthalpy and the Young s modulus, which is one of the three elastic moduli, is shown in Fig. 6 for various cubic phases, i.e. for the f.c.c. elements Al and Ni (Al), the f.c.c.-ordered NijAl (LI 2), the b.c.c. ordered FeAl, NiAl and CoAl (B2), and the cubic Laves phases CaAlj, YAI2, LaAl2, NbCr2, ZrLaves phases, i.e. there seems to be a common scatter band and the data of some other phases are near this scatter band. It has to... 

The mixed microlithotype clarodurite is intermediate in composition between durite and clarite with the proviso that while the amount of inertinite must be higher than the amount of vitrinite and the individual amounts of vitrinite, exinite, and inertinite should exceed 5%, the name structure also indicates a closer relationship to durite than to clarite. Clarodurite is also a common constituent of humic coals and the contaminants of this microlithotype are clays, pyrite, and siderite (ferrous carbonate). Conversely, duroclarite has maceral proportions that are closer to clarite than to durite. Thus, the proportion of vitrinite must exceed that of inertinite and the proportions of vitrinite, exinite, and inertinite present should exceed 5%. This microlithotype occurs in fairly thick bands and is a common constituent of most humic coals. 

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