bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical heterogeneity among adjacent coal microlithotypes — implications for oil generation and primary migration from humic coal
Authors: Stout Scott A. 
Published: April 2008

Abstract

Laser radiation focused onto a coal polished perpendicular to bedding has been used to thermally extract and pyrolyse the organic matter from three adjacent microlithotypes in a Tertiary, autochthonous, hydrogen-rich, sub-bituminous (early catagenesis/bituminization stage) humic coal from Indonesia. The distribution of hydrocarbons released during laser irradiation are shown to vary on a millimetre scale between adjacent humotelinite-, liptodetrinite-, and resinite-dominated microlithotypes. This variability is not due to varying thermal maturity but rather to (1) the inherent chemical variability of the macerals comprising each microlithotype; and/or (2) the presence of migrated, or non-indigenous, bitumen/oil. Hydrocarbon yields from each microlithotype suggest that primary migration between microlithotypes has occurred. Specifically, long chain
n
-alkanes and isoprenoids, which were most likely generated in the cutinite-derived liptodetrinite-dominated microlithotype (liptoclarite), are much more abundant in the overlying liptinite-free, humotelinite-dominated microlithotype (telite) and in the underlying resinite-dominated microlithotype (resinoclarite). These observations suggest that while the type of macerals plays an important role in the generation of oil within coals, it is the physical association between macerals (i.e. the microlithotypes present) which significantly influences the primary migration of oil within, and expulsion of oil from, coal seams. Thus since coals are extremely variable, both chemically and physically, generalizations suggesting all liptinite-rich humic coals can act as oil source rocks may be misleading. Liptinite-rich humic coals with high concentrations of finely-admixed liptinite and huminite macerals (e.g. liptodetrinite in a humodetrinite and mineral matrix, as would occur in microlithotypes with a detrital origin) may permit both oil generation
and
expulsion. Characteristics of the telite suggest, due to their high absorptive capacities and (micro)-porosity throughout most of bituminization/catagenesis, coals which contain an abundance of massive huminite macerals (e.g. humotelinite or gelinite) may tend to trap hydrocarbons generated from nearby or encased liptinites within their networks. Such macerals (the precursors to desmocollinites in bituminous coals) may become relatively hydrogen rich and often fluoresce under uv light and may not expel hydrocarbons until they are subsequently cracked to gas.
Coal-bearing strata as source rocks — a global overview
Authors: Macgregor Duncan S. 
Published: April 2008

Abstract
Compilation of a global source rock database has shown that coal-bearing sequences are significant oil generators only in very specific and relatively uncommon geological settings. Coals and associated carbonaceous shales are thought to be the primary oil-prone source facies in Australasia and an important secondary source facies in Southeast Asia. In other regions of the world, there is, however, no evidence that they have expelled major quantities of oil. In terms of their contribution to the worldrss petroleum reserves, coal measures are the origin of relatively minor proportions of oil, but of significant amounts of gas. Coal sequences that are believed to have expelled significant amounts of liquid hydrocarbons seem to be restricted to two palaeoclimatic and palaeobotanical ‘fairways’.

1.
Tertiary angiosperm assemblages within 20° of the palaeo-equator.

2.
Late Jurassic-Eocene gymnosperm assemblages formed on the Australian and associated plates.

The reasons for this are not well understood. Multidisciplinary research work is recommended to compare these oil-prone coals with the much greater volumes of apparently gas-prone coals deposited outside these regions.
Fluid flow and heat transfer in sedimentary basins
Authors: Jessop Alan M. , Majorowicz Jacek A. 
Published: April 2008

Abstract
One of the major assumptions underlying the science of geothermics over the last 100 years has been that heat is transported through the Earth’s crust only by conduction, except in the immediate vicinity of active volcanoes. In old shields this assumption may be justifiable, but in sedimentary basins the ability of water to move through permeable aquifers provides a means of heat transport that may under certain conditions be as effective as conduction.
The thermal history of a basin depends on its tectonic origin and the circumstances of its development. The dissipation of excess heat associated with basin formation and the transfer of the continuous heat supply from the basement depend on the thermal properties of the strata and their water content. In some basins widespread contrasts of heat flow are observed, both laterally and vertically, suggesting forced convection by water migration. In basins where part of the surface is above sea-level a hydrological drive may be inferred from the topographic surface. In sub-sea basins this drive is not available in the same form. Nevertheless, patterns of heat-flow variation have been observed for which some form of water flow seems to be the most probable explanation.
A complete quantitative description of the present thermal state has not yet been developed for any basin. Some two-dimensional numerical models have been developed, but, since flow directions may vary between aquifers, three-dimensional models must be the ultimate objective. There is scope to extend such models to the geological past by using palaeotemperature indicators such as vitrinite reflectance and fission-track measurements. So far we have been able to establish only an understanding of the principles and processes that control the thermal state of basins, so that detailed description of small parts or two-dimensional models may be developed.
Earthquakes, strain-cycling and the mobilization of fluids
Authors: Muir Wood R. 
Published: April 2008

Abstract

Employing empirical observations of the hydrological changes that follow major earthquakes, it becomes possible to predict subsurface fluid flows that accompany tectonic activity. Coseismic hydrological changes are found to be critically dependent on the style of fault displacement. Normal faults involve post-seismic compressional elastic rebound and displace large volumes of fluid from the crust: rainfall equivalent discharges have been found to exceed 100 mm close to the fault and remain above 10 mm at distances greater than 50 km; the total volume of water released in two M7 normal fault earthquakes in western USA was 0.3–0.5 km
3
. In contrast, reverse fault earthquakes involve extensional elastic rebound that increases crustal porosity, drawing fluids into the crust. The magnitude and distribution fo the water-discharge for normal fault earthquakes has been compared with deformation models calibrated from seismic and geodetic information, and found to correlate with the crustal volume strain down to a depth of up to 5 km.

These results suggest that fluid-filled cracks are ubiquitous throughout the brittle continental crust, and that these cracks open and close through the earthquake cycle. By repeatedly drawing fluids into microcracks distributed throughout a very large volume of rock, strain-cycling can achieve very significant chemical fractionation. Different classes of tectonics impose particular configurations of fractures and according to the origin of fluid recharge, lead to a range of different types and styles of mineralization. Seismic strain-cycling can also produce primary and secondary oil migration within a single causative mechanism.
Fluid flow in actively deforming sediments: ‘dynamic permeability’ in accretionary prisms
Authors: Stephenson E.L. , Maltman A.J. , Knipe R.J. 
Published: April 2008

AbstractRecent investigations into active accretionary prisms have emphasized both the importance of the deformation/fluid-flow interplay in governing fundamental aspects of prisms and the need for quantitative data on the processes. Even the basic parameter of permeability is little known in this and other geological settings where the sediments are undergoing active deformation. New experimental data are presented which show that permeability during accumulating strain, here called thedynamic permeability, is not a static value but is highly variable. Moreover, microstructural analysis and precise determination of permeant volume reveal that this dynamic permeability is not solely the varying capacity of the deforming medium to transmit fluid, a quantity here called theDarcyan permeability, but includes a contribution to the amount of permeant from the medium itself. In the laboratory experiments this additional contribution, called thedynamic component, arises from pore-volume fluctuations associated with microstructural changes, but in nature there may be further mechanical and chemical effects. Applying conventional methods of permeability determination to an actively deforming sediment will necessarily include this dynamic component in the measurement, a consideration relevant to a variety of geological and engineering situations.
Origin and nature of trace element species in crude oils, bitumens and kerogens: implications for correlation and other geochemical studies
Authors: Filby Royston H. 
Published: April 2008

Abstract

Crude oils and bitumens contain trace elements whose abundances range from less than a part per billion (ppb) to more than several thousand parts per million (ppm). Nickel and vanadium are usually the most abundant metals with values ranging up to 200 ppm Ni and 2000 ppm V. Abundances of other trace elements are generally less than 100 ppm. Nickel and vanadium occur in oils and source-rock bitumens as metalloporphyrins and non-porphyrin species. The nickel and vanadium porphyrins are predominantly DPEP or etio complexes of Ni
2+
or VO
2+
although smaller amounts of benzo and other complex porphyrins are found. The metalloporphyrins are formed during early diagenesis of source rocks and the relative abundances of nickel and vanadium are related to the depositional environment. The origin of the non-porphyrin nickel and vanadium complexes and the complexes of other trace elements in crude oils may be primary or secondary. Primary processes include release of metal complexes from kerogen during categenesis and formation of metal-organic complexes by mineral-kerogen reactions during catagenesis. Secondary processes such as interaction of oils with mineral matter or formation waters during migration, maturation or biodegradation may also affect the concentrations of some elements in crude oils, e.g. Hg.
Organic matter alteration and fluid migration in hydrothermal systems
Authors: Simoneit Bernd R.T. 
Published: April 2008

Abstract

Hydrothermal systems associated with oceanic spreading centres are now recognized as relatively common phenomena, and the organic chemistry occurring there is geologically rapid and novel. Especially in the marine hydrothermal systems at water depths >1.5 km, this chemistry proceeds at high temperatures (up to >400° C) and high pressures (>150 bar) in an aqueous open flow medium. Continental systems may also be of interest, as for example failed or dormant rifts and regions around piercement volcanoes. Organic matter alteration to petroleum hydrocarbons by reductive reactions occurs in hydrothermal systems over a wide temperature window (
c.
60 to >400° C), under high pressure, and in a brief geological period of time (years to hundreds of years). Thus, the products are considered to be in a metastable equilibrium state during their brief formation and residence times at high temperatures. These conditions are conducive to organic chemistry which yields concurrent products by reduction (due to mineral buffering), oxidation (high thermal stress) and synthesis. Therefore, this brief time interval coupled with the wide range of hydrothermal petroleum compositions indicates that organic matter maturation and petroleum generation, expulsion and migration occur as an overlapping continuous process during hydrothermal activity. The behavior of organic matter (CH
4
-C

40
+

) in near to supercritical water, in many cases with associated high concentrations of CO
2
and methane, needs to be further characterized in order to understand the implications of this novel phenomenon in geological and geochemical processes.
What is a mineral resource?
Authors: Riddler G. P. 
Published: April 2008

Abstract
Mineral resource evaluation is one of a whole spectrum of quantitative methods which have been used since biblical times for the purpose of improving the process required to aid problem-solving and to increase the quality of strategic management decisions at all levels. Such evaluation leads to the classification of mineral resources. It is important to have a clear knowledge of how mineral resources are classified and what the classification nomenclature actually means to ensure decisions are based on a sound understanding of criteria applied.
As interest for investment in mineral resource development spreads into Eastern Europe and the former Soviet Union, the need for some form of harmonization in terminology, nomenclature, criteria, as well as the approach to the classification process for the definition of mineral resources has again been highlighted.
The approach to quantitative studies is discussed, and guidelines are given that may improve mineral reserve and resource estimates so that implementation failure of mining projects can be avoided.
Approaches to the classification of mineral resources are reviewed along with the uses made of such mineral resource information.
The argument is put for a standard approach to mineral resource classification and consistency of international nomenclature with a discussion of some of the related problems. Principles are established which may suggest a way forward illustrated by a recent major resource assessment project.
Classification of mineral reserves in the former Comecon countries
Authors: Jakubiak Z. , Smakowski T. 
Published: April 2008

Abstract
Classification of reserves in the former Comecon countries is based on two reference axes: the abscissa represents the degree of reserve identification and the ordinate shows the possibility of economic utilization. Accordingly, reserves are classified as documented and prospective and as economic and uneconomic.

Documented reserves are divided into categories A, B, C
1
and C
2
. The first two of these categories relate only to developed and blocked reserves, with category A being in practical terms restricted to reserves under advanced exploitation, often at a stage nearing exhaustion. Category C
1
comprises reserves which have been identified and examined to such an extent as to enable a positive definition of their suitability for exploitation; these reserves are often in early production phases. Category C
2
relates to reserves which have been identified and documented at a preliminary stage only. Terminology of prospective reserves differs from country to country. In the former USSR and in the majority of other countries that adopted this classification, prospective reserves are divided into categories P
1
, P
2
and P
3
. However, in the classification used in Poland, on which this paper is based, prospective reserves are divided into prognostic reserves in categories D
1
, D
2
and D
3
and theoretical reserves in category E, categories D
1
and D
2
being equivalent to categories P
1
and P
2
respectively and combined categories D
3
and E roughly equivalent to category P
3
. Included in category D
1
are reserves either in areas adjoining documented reserves classified in category C
2
or reserves that occur at depths considered to be uneconomic. Assigned to category D
2
are reserves inferred from surface showings and indirect indications and quantified on the basis of statistical analysis of reserves known in similar mineralized structures in the proximity, whilst category D
3
includes reserves inferred from indirect indications alone. Finally, theoretical reserves E are deducted only from regional structural, lithological, metallogenic and other considerations.

Reserves in categories D
2
and above are divided along the ordinate into economic and uneconomic on the basis of the so-called criteria of balance defined by authorities in charge of the project(s). In centrally-planned economies the selection of these criteria generally reflected prevailing economic policies and priorities rather than profit considerations. Another set of criteria called the criteria of workability is then applied to economic reserves to define mineable reserves and these are called industrial reserves.

Put in the context of the IMM definitions, categories A and B are equivalent to measured mineral resources, categories C
1
and C
2
are broadly comparable to indicated mineral resources, whilst prospective reserves straddle the fields covered by indicated resources and mineral potential. Industrial reserves are comparable to the mineral reserve category as defined by the IMM definitions.
Fault interpretation from coal exploration borehole data using SURPAC2 software
Authors: Gribble P. D. 
Published: April 2008

Abstract
The use of isopach or contour plans for geological surfaces as the basis for fault interpretation of coal data, even when a dense drilling pattern has been applied, is often unsatisfactory. These plans tend to ‘smooth’ or underemphasize the effects of faulting, making assessment of the likely fault pattern difficult.

Within the
surpac2
Software system a series of modelling tools is available to assist with this interpretation process. An appropriately oriented grid is overlain on a digital terrain model (DTM) of the geological surface in question to regularize the data. The dip between data points is calculated, and a model of dip change created using the DTM method. A new contour model, which highlights trends in dip change, is produced, clearly showing likely fault traces and throw. This model may be sectioned to illustrate more graphically the disturbed and undisturbed areas. The fault model is then used as the basis for interpretation, to be compared with other models of the geology, and known local and regional faulting trends. Use of the macro facilities within
surpac2
allows a series of surfaces to be rapidly analysed to build up a picture of likely fault continuity and pattern within the succession.

Once the fault pattern is established, it can then be used elsewhere in
surpac2
for further modelling and evaluation. Application can be simple, such as the formation of boundaries of faulted areas for estimation of mineable coal resource. More complex modelling can be achieved by interaction between geological surfaces and the fault surfaces defined by the interpretation process. A complete model of the faults and their impingement on the coal and associated layers is formed, for further use within the
surpac2
design tools.
Optimal open pit design: sensitivity to estimated block values
Authors: Dowd P. A. 
Published: April 2008

Abstract
This paper discusses two important, and often overlooked, aspects of optimum open pit design: the information and support effects. Pit designs are ultimately based on estimated block grades and, as such, their optimality can only ever be approximate; as the errors of estimation of the block grades increase the pit design will deviate more and more from true optimality. Estimation errors depend on the amount of data available (information effect) and on the size of the block to be estimated (support effect). There is a lower limit to the block size used in grade and revenue block models for pit design and this lower limit is determined by the drilling grid. The use of blocks which are significantly smaller than the drilling grid will produce block models which will yield erroneous pit designs. Geostatistical simulation is used to quantify these effects for a particular case and to demonstrate the most effective way of dealing with small selective mining units at the planning stage.
Dilution in underground bulk mining: implications for production management
Authors: Scoble M. J. , Moss A. 
Published: April 2008

Abstract
The minimization of dilution represents a major opportunity for quality improvement in Canadian underground metal mining. The characteristics of the principal forms of dilution, planned and unplanned, are reviewed. These are controlled by quality factors relating to exploration, mine design and stoping practice. The scope for quality improvement and the need for technology development is analysed in the context of underground bulk mining. The design principles for a production management system which tightly monitors and controls dilution are proposed. This revolves around the reconciliation of accurate and timely data on ore reserves, stope fragmentation, cavity morphology, rockmass integrity, and production statistics. Particular priority will require to be placed on continued sensor development for measurement of cavity geometry, borehole deviation, grade and tonnage. This is intended to exploit a rapidly evolving underground communications technology and forms part of a rationale for future computer integrated mining.
The optimal design of quarries
Authors: Dowd P. A. 
Published: April 2008

Abstract
This paper describes the various general approaches to the optimal design of pits and quarries. Three types of deposit and corresponding numerical models can be distinguished and in each case a particular method of optimization can be used. In the most general case computer methods must be used to construct optimal pit/quarry outlines on the basis of a regular, three-dimensional revenue/grade block model. The paper includes a Fortran algorithm for a simple implementation of the Lerchs-Grossmann method for optimal pit/quarry design.