Geologic and petrologic examination of soft brown coals holds large potential for exploration and raw material characterization. Thus, the coal composition can be identified, the micro hardness can be measured and different micro photometric parameters can be quantified. By investigating upgrading products or solid residues it is also possible to receive information about the technological behaviour of special components as well as to reconstruct the process conditions within the reactor and to substitute complex coal chemically analyses.

The Middle Eocene lignites of the Zeitz-Weißenfels coal mining area in central Germany hosted one of the most economically successful lithotypes of lignite deposits utilised in the paraffin industry of the 19th century, i.e. the pyropissite deposits. However, due to their economic significance, these rare lithotypes were almost completely mined out, such that presently only a few remnant deposits are known. Apart from the Zeitz-Weißenfels coal mining district, other pyropissite deposits were also encountered in other lignite mines, for instance, in the Hessian and Subhercynian Basins.

Mand-Raigarh coalfield is one of the largest coalfields in the Mahanadi basin. The Geological Survey of India carried out initial study primarily on exploration. However, detailed petrographic and geochemical characters of the coals have not been done so far. This investigation is an attempt for petrographic and geochemical appraisal of the coals. Moreover, effort is also made for possible interpretation on development of coal facies. The results drawn from 30 composite coal samples suggest coals are rich in vitrinite, with collotelinite as the dominant maceral while liptinite macerals register low concentration. Dominant mineral assemblages found were clay minerals, pyrite was recorded as disseminated, framboidal and euhedral forms, carbonates recorded were mainly siderites. The vitrinite reflectance random (VRo) mean values range from 0.44 % to 0.56 %, and the rank of coal is suggested as high volatile ‘B’ to ‘A’ sub-bituminous in rank. The rock–eval pyrolysis reveal TOC content varying from 37 % to 68.83 %, while low hydrocarbon generating potential is evident from low S2 and T max values. The Hydrogen Index (HI) versus Oxygen Index (OI) plot reveal that the samples belong to Kerogen type—II–III with input dominantly from terrestrial source, some samples also fall in Kerogen type—II domain indicating lacustrine input. Vitrinite reflectance result indicate that the samples are immature and approaching oil window, which is in agreement with data of the Rock–Eval parameters. The gelification index (GI) and tissue preservation index (TPI) indicate that the coal developed in a telematic set up with high tree density. The ground water index (GWI) and vegetation index (VI) demonstrate that the peat developed as an ombrogenous bog.

Helmut Jacob, an internationally known coal and organic petrologist, geologist, and lecturer passed away a year ago on 18 January, 2014 suffering from long health complications in Celle, Lower Saxony, Germany. As a devoted brown coal specialist, he founded the Organic Petrography Research Unit at the Bundesanstalt für Bodenforschung (BfB) (former Federal Institute for Geosciences and Natural Resources) in Hannover. His enormous activities included valuable contributions to the development of nomenclature and classification of brown coals at macroscopic and microscopic scales, carried out firstly within the Nomenclature Commission of the ICCP in the 60s under the leadership of Dr. M. Teichmüller and in the 70s under Dr. M. Wolf, among others. Helmut Jacob also provided important contributions on application of microscopy of briquettes to brown coal briquetting and coking. As a well-known petrologist, he also made substantial achievements in the establishment of nomenclature and classification of solid bitumens.

For coal conversion using pyrolysis or hydrogenation the prediction of the very complex processing behavior of coal is of prime importance. A first approach can be given by a systematic examination of the micropetrography of solid residues. Thereby, a threefold classification could be drawn, distinguishing between components of the original macerals, the coked material and the inorganic residues. In addition to this generally nomenclature, the components can also serve as indicators for the process course and efficiency, and can provide possible indications for process optimization.

This paper entails the results of petrological studies carried out on coal samples drawn from two lower Gondwana coal bearing horizons (Raniganj formation and Barakar formation) of the Singrauli coalfield, Son basin. It emerges from this study that the coals of this basin are banded in nature and are dominated by 'banded dull' and 'dull' components. Further, vitrinite and inertinite are the dominant maceral groups while the macerals of liptinite group occur in relatively low concentration. Chemically, the coals are high in volatile matter and ash contents. The study further reveals that the Jhingurdah top seam of Raniganj formation characteristically has elevated concentration of detrital macerals when compared with the coals of Purewa top, Purewa bottom and Turra seams of Barakar formation. Furthermore, it is evolved that these coals have been generated under a fluvio-lacustrine setting, largely from forest swamp, where an alternate oxic to mildly anoxic moor conditions prevailed.

The Deutsches EnergieRohstoff-Zentrum Freiberg (DER) is a strategic partnership between government, science and industry to develop innovative concepts and technologies for the peak and post oil era. Researchers and practitioners collaborate to develop technical innovations to make the energy sources coal and biomass sustainable and future-oriented. The centre addresses the issues of energy supply, security and sustainability through research into the non-energetic utilisation of coal, where coal is not simply burnt to produce energy, but used as raw material in production processes for chemicals, especially hydrocarbons. Therefore, DER engages in the development of innovative gasification and hydrogenation processes, as bridging technology between conventional fossil energy sources and renewables. The intention of the DER is to achieve technological leadership in the field of non-energetic coal utilisation, and to develop the institution into an international centre of excellence in R&D for the utilisation of coal and recent biomass.

Drilling the Milano mud dome situated in the Olimpi field on the northern flank of the Mediterranean Ridge accretionary complex has documented episodic eruptive activity over the last 1 to >1.5 million years. Mud extrusion is related to backthrust faulting due to subduction of the Africa Plate beneath a relatively rigid backstop of Cretan continental crust. The mud dome is mainly composed of mud breccia with up to 65% of polymictic clasts embedded in a clayey matrix.Previously published results from petrography and new maturity data of both clasts and mud matrix presented here allow us to distinguish between two different areas of provenance: (1) A northern province, characterised by a trimodal maturity distribution of organic material, was found for the majority of the mud breccia matrix samples studied. Similarly, some of the clasts studied show the three vitrinite-reflectance populations. These are carbonate and sandstone clasts, inferred to have been eroded from the upper nappes of the Cretan thrust stack after exhumation in the late Miocene, as well as mudstone clasts. Clay mineralogy of these clasts coincides with earlier results on seafloor samples of a northern provenance, recovered in the Hellenic Trench, (2) A southern provenance is proposed for a second group of clasts with a bimodal maturity distribution, not showing the second population (0.64-0.82% Rm). These clasts are litharenites, calcilutites and calciturbidites of a proposed southern provenance, i.e. North Africa.The presence of huminite in all clast and matrix samples studied (0.26-0.45% Rm) is indicative of a shallow burial history. Estimates regarding the depth of mobilisation of the mud using the regional thermal gradient indicate burial not deeper than 2 km below the seafloor. Organoclastic matrix components mirror the northern clast provenance so that, prior to subduction and subsequent extrusion, deposition of the mud in the Northeastern Mediterranean can be inferred. We propose a model in which sediment from the north was trapped within the forerunner of the Pliny trench; this sediment was deposited above the backstop of the subduction complex, which was later overridden by the accretionary prism as a result of incipient collision; density inversion forces then favoured uprise and extrusion of underconsolidated sediments as mud volcanoes. The mud matrix was probably largely derived from a Messinian succession, although alternatives remain possible. (C) 2000 Elsevier Science B.V. All rights reserved.

Mud volcanism on the Mediterranean Ridge is caused by extrusion of overpressured sediments, with consequent formation of spectacular dome-shaped features composed of mud breccias at the seafloor. The organic material in the mud breccia of the Napoli mud volcano is a mixture of different facies, stratigraphic origin and thermal maturities. One portion is synsedimentary organic material with only minor diagenetic alterations and represents sedimenting material that was embedded into the mud volcano during its extrusion. The mud breccia also contains thermally mature organic material of mainly terrestrial provenance with algae of fresh- and brackish-water origin. Vitrinite reflectance data of this maturity generation range from 0.65 to 0.90% Roil and thus characterize thermally mature source rocks, a rank which is corroborated by fluorescence and molecular characteristics. The predominance of vitrinite in the maceral assemblages and the occurrence of biomarkers of terrigenous origin suggest that the major part of the mud matrix derives from a lacustrine or riverine sedimentary unit in the subsurface, possibly from the Messinian stage. A third generation of organic material includes inertinites and vitrinites of high reflectance, which represent recycled organic matter present in any marine sediment. By use of the Lopatin method for modelling the thermal maturation of hydrocarbon source rocks from the vitrinite reflectance data, we calculated that the depth of mobilization ranges from 4900 m to 7500 m, depending upon the temperature gradient used.

N.m.r. and i.r. spectroscopy as well as fluorescence microscopy are applied to characterize hydrogenation residues of lignite lithotypes. The combination of spectroscopic and microscopic techniques allows a detailed description to be given of coal decomposition during the liquefaction process under several conditions. In particular, different decomposition steps in the coal network can be detected by n.m.r. and i.r. spectroscopy. A quantitative component analysis of the residues is performed using fluorescence microscopy. A new kind of residue constituent is detected indicating mild hydrogenation conditions for lignites. Furthermore, the conversion of the lignite macerals under different hydrogenation conditions is studied to obtain information on the formation of typical residue constituents. The techniques used complement each other and conclusions can be drawn about the hydrogenation process on lignite lithotypes.