Allegheny Formation Research Articles

Aspects of rare earth element enrichment in Allegheny Plateau coals, Pennsylvania, USA

The Allegheny Plateau in western Pennsylvania, western Maryland, and northern West Virginia has relatively flat-lying strata with southwest-northeast-trending anticlines cored by splay faults originating from the thrust faults and southeast-northwest-trending lineaments. The lineaments define both the structural relief of the anticlines and the coal rank. Coal rank in the Pennsylvanian Allegheny Group coals is medium volatile bituminous in the region of less-prominent structural relief and low volatile bituminous in the region with more pronounced anticlines.Zinc and Cl exhibit high values in coals in the vicinity of the lineaments. Although coal rank was not a parameter in the Principal components analysis, the highest rank coals clustered together in a quadrant defined, in part, by the Zn concentration. Zinc was selected as a parameter due to its possible link with hydrothermal mineralization and Zr and TiO2/Al2O3 were selected based on their presumed association with detrital mineral influences. The highest rare earths + Y values in benches of the Lower Kittanning coal were found at sites close to the lineaments.Negative or negligible Ce anomalies (δCe) and strongly positive Gd anomalies (δGd) suggest marine or hydrothermal influences and negative Eu anomalies (δEu) along with high TiO2/Al2O3 values suggest a terrestrial input. The plots of δCe vs. δGd and δCe vs. δEu show that the low volatile bituminous coals are segregated from the other coals, suggesting that the factors that influenced coal rank also influenced the distribution of the rare earth elements.

A new dissorophoid temnospondyl from the Allegheny Group (late Carboniferous) of Five Points, Mahoning County, Ohio (USA)

AbstractA small temnospondyl skull from the upper Carboniferous Allegheny Group of Five Points, Ohio, is referred to a new dissorophoid, Palodromeus bairdi n. gen n. sp. The complete skull with mandibles is preserved in counterparts. It is characterized by, (1) elongated slit-like choana; (2) postfrontal, postorbital, and supratemporal bearing a distinct ridge; and (3) reduced parietal only two-thirds the length of the frontal. Phylogenetic analysis confirms a dichotomy between amphibamiforms and olsoniforms and places Palodromeus bairdi n. gen. n. sp. at the base of the olsoniforms, revealing an early stage in the evolution of that clade.UUID: http://zoobank.org/3871e443-7888-4439-a7c1-9463bc4d87ab

Paleohydrology and Machine-Assisted Estimation of Paleogeomorphology of Fluvial Channels of the Lower Middle Pennsylvanian Allegheny Formation, Birch River, WV

Rivers transport sediments in a source to sink system while responding to allogenic controls of the depositional system. Stacked fluvial sandstones of the Middle Pennsylvanian (Desmoinesian Stage, ~310 – 306 Ma) Allegheny Formation (MPAF) exposed at Birch River, West Virginia exhibit change in sedimentary structure and depositional style, reflecting changes in allogenic behavior. Paleohydrologic and numerical analysis were used to quantify geomorphological and paleohydrologic variations reflected by MPAF fluvial deposits with the goal of understanding the controls on resulting fluvial sandstone architecture in these different systems. Channel body geometry, sedimentary structures, and sandstone grain size distribution were used to reconstruct the paleoslope and flow velocity of the MPAF fluvial systems. In order to enhance paleohydrological estimates, machine learning methods including multiple regression and Support Vector Regression (SVR) algorithms were used to improve the dune height, and channel depth estimated from cross-set thickness. Results show that the Channel depths of the lower MPAF beneath the Lower Kittanning coal beds tend to decrease upsection; this decrease may reflect a transition from fluvial systems formed in a humid ever-wet climate to fluvial systems formed in less humid, seasonally wet, semi-arid climate. Paleohydraulic estimations enabled the evaluation of hydraulic changes in the fluvial depositional systems of the Appalachian Basin during the Desmoinesian stage. Paleoslope estimates indicated that the slope was low which indicated that the fluvial gradient response was not driven by the effect of tectonic subsidence or uplift and sea-level change.

Evaluation of stress-control layout at the Subtropolis Mine, Petersburg, Ohio

The Subtropolis room-and-pillar mine extracts the Vanport Limestone (Allegheny Formation, Pennsylvanian System) near Petersburg, Ohio. Strata instability problems associated with excessive concentrations of lateral stress caused the mine operator to implement a change in layout design. This mining method has been identified as a stress control layout and has been used by other underground stone mines in the past with varying degrees of success. Practical experience has shown that entry headings advance in the direction of the principal lateral stress, producing lower stress concentrations with better mining conditions. It is important to minimize stress concentrations along the mining front, so an arrow-shaped advance is recommended. This technique advances more developments (headings) in a “good” direction and reduces developments (crosscuts) in the “bad direction.” As is expected, the stress control layout enhances the potential for shear failures in crosscuts. It is, therefore, important to focus crosscut engineering interventions that either: (a) lower stress concentrations (for example, an arched roof) or (b) enhance strength of the strata containing the shears (for example, rock reinforcement). This study focuses on observing strata conditions on a regular basis and monitoring the response of these strata to changing geologic and mining conditions through 3D Dynamic LiDAR scans.

Characterization and ecological significance of a seed bank from the Upper Pennsylvanian Wise Formation, southwest Virginia

AbstractSoil seed banks are important to the maintenance and restoration of floras. Extant seed banks exhibit unique characteristics with regard to the distribution of seed size and seed density. Seeds were recovered from the Upper Pennsylvanian Wise Formation in southwest Virginia. Structurally preserved seeds were also examined from coal balls of the Pennsylvanian Pottsville and Allegheny Groups, Ohio. The size distribution of the seeds from the Wise Formation is similar to that of structurally preserved seeds of the Upper Pennsylvanian Pottsville and Allegheny Group coal balls. In contrast, the seed size distributions in extant wetland, grassland, woodland and forest habitats are significantly narrower than that of seeds from the Pennsylvanian seed banks. Larger seeds are less dependent on light for germination, and aid in seedling establishment more than smaller seeds, especially in dense stable forests where disturbance events are rare. Large seed size may contribute to increased seed longevity, which reduces the effect of environmental variability on seed germination and development. The significantly larger size of the Palaeozoic seeds may have imparted an advantage for seedling establishment in the dense Palaeozoic forests. The preponderance of large seeds may be a result of the absence of large seed predators (e.g. herbivorous tetrapods), and may have been an evolutionary strategy to minimize damage to the embryo from a predator population dominated by small invertebrates with chewing or sucking mouthparts. The estimated seed density of 192 seeds/m2in the Palaeozoic seed bank falls within the range of modern seed banks, but at the lower end of modern seed bank densities in a variety of habitats.

Physiographic and Anthropogenic Factors Influencing Fish Community Composition in Tributaries to the Youghiogheny River in Pennsylvania

Abstract We evaluated the status of fish communities from 30 first- to fourth-order wadeable Youghiogheny River (YR) tributaries located in the Allegheny Mountain Section (AMS) and Pittsburgh Low Plateau (PLP) physiographic provinces in Pennsylvania. The AMS is underlain primarily by geologic formations dominated by the Allegheny Group, while the Casselman Formation underlies much of the PLP. Streams draining the AMS were primarily forested, low-order (1–2), high-gradient, and poorly-buffered with minimal cultural influences. By contrast, the majority of the PLP was drained by low-gradient, well-buffered, valley streams of order ≥2, with varying anthropogenic influences. In order to characterize connectivity, all streams were sampled from their mainstream junctions to an endpoint 200 m upstream utilizing back-pack electrofishing. A total of 366 fishes representing seven families, 17 genera, and 22 species were collected from AMS streams, while the PLP yielded 2738 fishes representing 8 families, 25 genera...

Analyses of geological and hydrodynamic controls on methane emissions experienced in a Lower Kittanning coal mine

This paper presents a study assessing potential factors and migration paths of methane emissions experienced in a room-and-pillar mine in Lower Kittanning coal, Indiana County, Pennsylvania. Methane emissions were not excessive at idle mining areas, but significant methane was measured during coal mining and loading. Although methane concentrations in the mine did not exceed 1% limit during operation due to the presence of adequate dilution airflow, the source of methane and its migration into the mine was still a concern. In the course of this study, structural and depositional properties of the area were evaluated to assess complexity and sealing capacity of roof rocks. Composition, gas content, and permeability of Lower Kittanning coal, results of flotation tests, and geochemistry of groundwater obtained from observation boreholes were studied to understand the properties of coal and potential effects of old abandoned mines within the same area. These data were combined with the data obtained from exploration boreholes, such as depths, elevations, thicknesses, ash content, and heat value of coal. Univariate statistical and principal component analyses (PCA), as well as geostatistical simulations and co-simulations, were performed on various spatial attributes to reveal interrelationships and to establish area-wide distributions. These studies helped in analyzing groundwater quality and determining gas-in-place (GIP) of the Lower Kittanning seam. Furthermore, groundwater level and head on the Lower Kittanning coal were modeled and flow gradients within the study area were examined. Modeling results were interpreted with the structural geology of the Allegheny Group of formations above the Lower Kittanning coal to understand the potential source of gas and its migration paths. Analyses suggested that the source of methane was likely the overlying seams such as the Middle and Upper Kittanning coals and Freeport seams of the Allegheny Group. Simulated ground-water water elevations, gradients of groundwater flow, and the presence of recharge and discharge locations at very close proximity to the mine indicated that methane likely was carried with groundwater towards the mine entries. Existing fractures within the overlying strata and their orientation due to the geologic conditions of the area, and activation of slickensides between shale and sandstones due to differential compaction during mining, were interpreted as the potential flow paths.

A provenance study of mineral matter in coal from Appalachian Basin coal mining regions and implications regarding the respirable health of underground coal workers: A geochemical and Nd isotope investigation

Abstract This study presents geochemical data produced from the analysis of coal and adjacent rock samples retrieved from coal mining regions in the U.S. to examine mineral matter provenance. Study sites included the Northern Appalachian Basin, where the units of interest were the Lower Kittanning Coal bed, the overlying Columbiana Shale, and the underlying paleosol (Allegheny Formation). Additional study sites were located in the Central Appalachian Basin, where sampling was conducted on strata associated with multiple coal beds of Middle and Lower Pennsylvanian age. The Central Appalachian Basin rock and coal samples were much lower in overall mineral matter and contained very little carbonate (calcite and siderite) or pyrite mineralogy, which was common at the Northern Appalachian Basin sites. Elemental analysis of rock samples indicated a trend of enrichment in Ca, Mg, Mn, Na, and K cations in the immediate overburden compared to the underlying rock in the Central Appalachian Basin. A similar trend was observed in coal related strata from the Northern Appalachian Basin which was attributed to epigenetic marine incursions. Rare earth element (REE) concentrations were determined in the samples, and showed Eu and Ce anomalies when normalized by chondritic values. The total REE content of the overburden is generally less than that of the underlying rock units. Neodymium isotopic analysis of the Lower Kittanning coal, overburden, and paleosol from the Northern Basin indicate partial resetting of the Sm–Nd system close to the time of deposition. The data indicate a common Appalachian source for the clastic mineral matter in the overburden, underclay, and coal mineral matter. The geochemical findings of this study may provide a viable method for distinguishing respirable dust sources in both Appalachian Basins. There are potential applications for this research to aid in the respiratory health of underground coal miners.

Reconnaissance spatial analysis of the hydrogeology of closed underground coal mines

A method is demonstrated to employ combined mapping and field techniques to unravel complexities in the hydrogeology of flooded and unflooded underground coal mines of shallow (120 m, 400 ft) depth. For a study area in the Appalachian coal basin, underground mines, coal outcrop, coal structure, and mine-drainage discharge locations were mapped onto an integrated geographic information system platform. The Upper Freeport coal seam (Allegheny Group) in the study area is relatively shallow (120 m, 400 ft), with many closed free-draining mines and numerous discharges. The mapping of coal outcrop and structure was accomplished using (1) high-resolution aerial orthophotographs, (2) digital outcrop polylines, and (3) a coal-bottom structure surface created by geospatial interpolation of point data mostly abstracted from original mine maps. Mapping results integrated with field measurements of mine-water discharge allow inference of likely pool locations and potential interconnections between underground workings, which are not apparent from mine maps alone. The results are reconnaissance level in that the interpreted pool locations and depths are unconfirmed by drilling or water level measurement; therefore, any action based on such results should be preceded by fieldwork to confirm hypotheses offered by the reconnaissance analysis. Nonetheless, such a preliminary interpretation of hydrogeological conditions based on little or no subsurface (well) water level information may be highly useful for both interpreting subsurface conditions and for planning future research. The technique is based on a combination of mine mapping, digital analysis of geologic structure, and surface reconnaissance fieldwork. Results are directly applicable to areas of reclamation of shallow coal mining where mine closures have resulted in an uncontrolled discharge of mine drainage.

Acid Mine Drainage Flowing from Abandoned Gas Wells

In northwestern Pennsylvania (USA), numerous abandoned natural gas wells are producing artesian flows of Fe-contaminated water. The origin of the polluted water has been generally assumed to be brines from the gas-producing sands. We sampled 20 artesian discharges where iron staining was conspicuous. The waters were not brines, but were more characteristic of acid mine drainage (AMD). The dominant cations were Fe, Ca, and Mg, while the dominant anion was sulfate. The study area has a long history of coal mining in the lower Allegheny formation; however, the coal beds are generally at higher elevations than the discharges. We propose that AMD formed in the coal mines is infiltrating into lower aquifers, moving outside the lateral limits of mining, and using abandoned gas wells as conduits to the surface. While flowing through the underlying sandstones, the AMD chemistry is modified by contact with siderite, the dominant carbonate mineral in this stratigraphy. This would suggest that current remediation strategies that emphasize plugging the pollution-producing gas wells may be ill-advised because the source of the polluted water is more shallow than currently assumed.

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Appalachian Corridor H will pass through Beaver Creek watershed in Tucker County, West Virginia. This is a sensitive area because numerous wetlands and reclaimed mined lands are located in the vicinity of the proposed highway. The West Virginia Division of Highways funded a project to assess the effects of the highway on the watershed. The two major coal beds in the watershed were Bakerstown, a member of the Conemaugh Formation, and Upper Freeport, a member of the Allegheny Formation. Bakerstown was mined and reclaimed in the 1970s, and Upper Freeport was mined and reclaimed in the 1960s. The dominant vegetation on the Bakerstown sites was grasses and legumes with scattered trees, while Upper Freeport sites were uniformly covered with red pine (Pinus resinosa Ait.). In order to document the existing conditions prior to the construction of the highway, a study was initiated to evaluate the properties and genesis of minesoils in the watershed. Six minesoil sampling points were located on Bakerstown sites and six were located on Upper Freeport sites. In addition, six sampling points were located on contiguous native soils. Soil profiles were described and horizons were sampled for laboratory physical and chemical analyses. The native soils were well drained to very poorly drained Inceptisols or Ultisols developed in alluvium or colluvium. Three of the six sampling points had fragipans. Minesoils developing on the Bakerstown sites had A horizons ranging from 3 to 16 cm thick. Sola of these soils ranged in thickness from 15 to 49 cm. Five of the six points had sola ranging from 15 to 33 cm thick. Minesoils on the Upper Freeport sites had A horizons that were 4 to 11 cm thick. Five of the six sampling points had sola ranging from 9 to 35 cm thick. One point had an uncommonly thick solum with Bw horizons described to 99 cm. Minesoils on both sites were classified as Entisols and Inceptisols. Although the depth of minesoil sola forming on the Upper Freeport and the Bakerstown sites was similar, fewer horizons were described per profile in Bakerstown minesoils. We attributed this horizonation difference to differences in parent materials. The rock fragments in Bakerstown minesoils were predominantly sandstones, whereas rock fragments in the Upper Freeport minesoils were a mixture of shale and sandstone.

Palynology of late Middle Pennsylvanian coal beds in the Appalachian Basin

Fossil spores and pollen have long been recognized as valuable tools for identifying and correlating coal beds. This paper describes the palynology of late Middle Pennsylvanian coal beds in the Appalachian Basin with emphasis on forms that assist both intra- and interbasinal coal bed correlation. Stratigraphically important palynomorphs that originate in late Middle Pennsylvanian strata include Torispora securis, Murospora kosankei, Triquitrites minutus, Cadiospora magna, Mooreisporites inusitatus, and Schopfites dimorphus. Taxa that terminate in the late Middle Pennsylvanian include Radiizonates difformis, Densosporites annulatus, Dictyotriletes bireticulatus, Vestispora magna, and Savitrisporites nux. Species of Lycospora, Cirratriradites, Vestispora, and Thymospora, as well as Granasporites medius, Triquitrites sculptilis, and T. securis end their respective ranges slightly higher, in earliest Late Pennsylvanian age strata. Late Middle Pennsylvanian and earliest Late Pennsylvanian strata in the Appalachian Basin correlate with the Radiizonates difformis (RD), Mooreisporites inusitatus (MI), Schopfites colchesterensis– S. dimorphus (CP), and Lycospora granulata– Granasporites medius (GM) spore assemblage zones of the Eastern Interior, or Illinois Basin. In the Western Interior Basin, these strata correlate with the middle-upper portion of the Torispora securis– Laevigatosporites globosus (SG) and lower half of the Thymospora pseudothiessenii– Schopfites dimorphus (PD) assemblage zones. In western Europe, late Middle Pennsylvanian and earliest Late Pennsylvanian strata correlate with the middle-upper portion of the Torispora securis– T. laevigata (SL) and the middle part of the Thymospora obscura– T. thiessenii (OT) spore assemblage zones. Allegheny Formation coal beds also correlate with the Torispora securis (X) and Thymospora obscura (XI) spore assemblages, which were developed for coal beds in Great Britain.

An alternative mineral-based hypothesis for atmospheric CO2-sinks

This paper presents a radically new hypothesis for the well-documented but hitherto not explained carbon sink observed over the Eastern United States. This hypothesis provides evidence for CO2 fixation in minerals, not the ocean or vegetation. From the mineralogical analysis of carbonates and carbonate carbon in some 60 samples of Upper Allegheny formation limestones, coal overburden shales and sandstones, water well precipitates, AMD sludges and down slope seep precipitates, we conclude that precipitation of iron and manganese carbonates may be a significant ongoing process. If the phenomenon is as wide spread as we believe, it likely could be a significant atmospheric CO2 sponge. In the case of the Appalachian coal fields stretching from western PA through parts of OH, WV, KY, etc, there are literally tens of thousands of cubic kilometers of candidate material available for this sponge effect.

Observations on the palynology, petrography and geochemistry of the Western Kentucky number 4 coal bed

Eight bench-column samples of the Western Kentucky Number 4 coal bed, collected from an area along the southern margin of the Western Kentucky Coal Field, were analyzed palynologically, petrographically, and geochemically to document both temporal and spatial variability among these parameters. The Western Kentucky Number 4 coal occurs near the top of the Tradewater Formation, is of Early Desmoinesian age, and is correlative with the lower part of the Allegheny Formation of the Appalachian Basin, and Late Bolsovian strata of western Europe. Palynologically, the coal is co-dominated by spores that were produced by lycopod trees ( Lycospora and Granasporites medius) and tree ferns. Thin-walled tree fern spores ( Punctatisporites minutus, P. minutus, P. rotundus) are more abundant than thick-walled forms ( Laevigatosporites globosus, P. granifer). Calamitean spores ( Calamospora and Laevigatosporites spp.) are locally abundant as is cordaitean pollen ( Florinites). Small fern ( Granulatisporites) and small lycopod spores ( Densosporites, Cirratriradites, Endosporites and Anacanthotriletes spinosus) are present, but occur in minor amounts. Temporal changes in palynomorph composition occur, but are not uniform between columns. Spatial variability among columns is also evident. Petrographically, the coal is dominated by vitrinite macerals, with telinite and telocollinite generally occurring more commonly than desmocollinite and gelocollinite. Basal benches typically contain high percentages of vitrinite; middle benches usually contain higher percentages of liptinite and inertinite. In about half the studied columns, the terminal coal benches show a slight increase in vitrinite. In the study area, the petrography of the Western Kentucky Number 4 coal is more uniform than the palynology. Ash yields and total sulfur contents are temporally uniform in some columns, but variable in others. In the latter case, higher percentages of ash and sulfur occur at the base of the bed and decrease up to the middle of the bed. The terminal benches of these columns often, but not always, show slight increases in ash or sulfur. Both syngenetic and epigenetic forms of sulfur are present in the Western Kentucky Number 4 coal. The high vitrinite contents and moderate to high sulfur contents suggest that the Western Kentucky Number 4 paleomire was mainly planar and rheotrophic throughout its developmental history. Groundwaters carrying dissolved solutes may have helped neutralize the normally acidic interstitial peat waters allowing for the production of sulfide minerals. Several of the columns with high sulfur contents at the base of the bed occur in faulted areas. The faults could have promoted the flow of groundwaters through the peat, providing an increased dissolved load for acid mitigation and sulfide formation. The concentration of sulfur at the base of the bed may be a function of the peat/underclay contact enhancing sulfide formation. The clay layer may also have acted as an impermeable boundary for downward moving groundwaters, causing mainly lateral, rather than vertical movement along the base of the coal bed.

Coalbed methane resource potential and current prospects in Pennsylvania

Coalbed methane gas content analyses from exploratory coal cores and existing data indicate that gas content generally increases with increasing depth and rank. The coal beds studied are from the Main Bituminous field of Pennsylvania (which currently contains 24 coalbed methane pools) and the Northern and Southern Anthracite coal fields. They range from the Middle Pennsylvanian Allegheny Group to the Late Pennsylvanian–Early Permian Dunkard Group. Previous US Bureau of Mines studies revealed gas contents from 0.4 to 13.8 cm 3/g at depths of 99 to 432 m for the bituminous coal beds of the Allegheny Group. More recent core data from the Allegheny Group yielded gas contents from 2.2 to 8.9 cm 3/g at depths from 167 to 387 m. In the Anthracite region of eastern Pennsylvania, the little data that are available show that gas content is anomalously high or low. Gas yields from test holes in eastern Pennsylvania are low with or without artificial stimulation mainly due to the lack of a good cleat system. Overall estimates of coalbed methane resources indicate there may be 1.7 Tm 3 (61 Tcf) of gas-in-place contained in the Northern Appalachian coal basin. The amount of technically recoverable coalbed methane resources is projected by the US Geological Survey National Oil and Gas Resource Assessment Team [US Geological Survey National Oil and Gas Resource Assessment Team, 1996. 1995 National assessment of United States oil and gas resources—results, methodology, and supporting data, US Geological Survey Digital Data Series DDS-30, CD-ROM, Denver, CO, 80 pp.] and Lyons [Lyons, P.C., 1997. Central-northern Appalachian coalbed methane flow grows. Oil and Gas Journal 95 (27) 76–79] at 0.3 Tm 3 (11.48 Tcf). This includes portions of Pennsylvania, Ohio, West Virginia, and a small part of Maryland. Consequently, a mapping investigation was conducted to evaluate the regional geology of the bituminous coal-bearing intervals in southwestern Pennsylvania and its influence on coalbed methane potential. Phase I of this study involved the entire Pennsylvanian coal-bearing interval of southwestern Pennsylvania. Phase II focused on a stratigraphic delineation and evaluation of Allegheny Group coal beds and associated sandstones. Several prospective coal beds and associated facies relationships with channel–fill sandstones were determined. Possible non-coal scenarios for coalbed methane include erosional contacts between coal beds and overlying channel–fill sandstones and areas of stacked channel–fill sandstones. Repetitive sequences of coal accumulation are stacked, commonly with shale interburden, and are also potential coalbed methane targets. Additional Pennsylvania Geological Survey drilling/coalbed methane sampling occurred in Armstrong, Beaver, Cambria, Greene, Lawrence, Somerset, and Washington Counties. Raw coalbed methane desorption data tables/graphical displays of gas contents versus depth, thickness, and time, and average composition and heating values from coal beds of the Allegheny Group to the Dunkard Group are available at the Pennsylvania Geological Survey. Further information on cross-sections, isopleth maps, isopach maps, raw drillhole data, and ownership issues can also be obtained from the same source.

Production characteristics and reservoir analysis of coalbed methane reservoirs

Six Appalachian coalbed methane (CBM) projects are reviewed and evaluated in terms of reservoir engineering techniques and CBM recoverability. These include three non-mine-related projects in the northern Appalachian basin, one non-mine-related, and two mine-related projects in the central Appalachian basin of southwestern Virginia. Generally, low production rates and low CBM reserves are characteristic of the central and northern Appalachian basin; therefore, minimizing production costs is fundamental to the economic success of a CBM project in these regions. Well deliverability is determined through permeability testing and through production data analysis using a reservoir simulator to history match historic production data. All of the non-mine-related projects utilize vertical wells with well spacings of 60 to 100 acre (0.23–0.40 km 2) that produce from multiple coalbeds at depths as much as 762 m. The targets are coalbeds of the Pocahontas and New River Formations and correlative Lee Formation. In the Nora Field of Virginia (Equitable Resources, developer), well spacing is 60 acre (0.23 m 2), and recoverability is high (30–60% of initial gas in place). Well stimulation is by foam or water as the fracture medium. The average gas in place is 675 MMscf well −1, and the expected lifetime of the wells is 30 years. Cost of water disposal is a major economic factor in CBM development in the Appalachian basin. Water disposal is accomplished by using water disposal holes (injection wells) rather than surface water discharged, which is generally not permitted. Water disposal in the central Appalachian basin involves relatively low volumes of water (30 STB day −1, declining to 1 to 2 STB day −1). In the northern Appalachian basin in Indiana County, PA (Belden and Blake, developer), vertical CBM holes penetrate six to eight Allegheny Formation coalbeds. Water and a sand proppant are used for stimulation. Production levels are low (<100 Mcf day −1 well −1). The life of a vertical CBM hole drilled in advance of mining is 3 to 5 years. This type of hole may be converted to a gob hole after mining is completed. Gob gas is recovered mainly from coalbeds above the mined coalbed and has high recoverability of as much as 10 MMscf day −1 well −1. Horizontal CBM holes produce almost pure methane and typically have 1 year of production.

Pennsylvanian continental cyclothem development: no evidence of direct climatic control in the Upper Freeport Formation (Allegheny Group) of Pennsylvania (northern Appalachian Basin)

The occurrence of lacustrine carbonates in the Allegheny Group (upper Middle Pennsylvanian) continental cyclothems of the northern Appalachian Basin has been attributed to climatic alternation of wet (coal deposition) and dry (carbonate deposition) periods. However, we present evidence from facies associations, coal and carbonate petrography, and carbonate stable isotope geochemistry for a uniformly wet climate throughout deposition of one of the earliest continental cyclothems, the Upper Freeport Formation (UFF). We propose a depositional model comprising a large wetland complex drained by an anastomosed fluvial system containing a mosaic of channels, freshwater siliciclastic and carbonate lakes, and peat bogs/swamps on a siliciclastic floodplain. Carbonate phases represent bio-induced precipitates modified by lake dynamics, and not evaporative deposits. Absence of covariant isotopic trends between δ 18O and δ 13C and a relatively small range of δ 18O values (−1.9 to −6.4% PDB), that are close to or lighter than predicted paleoprecipitation for the Pennsylvanian equatorial regions, indicate hydrologically open, short residence time lake systems, in support of our sedimentary model. Combined sedimentologic and isotopic data do not indicate reduced effective moisture (precipitation-evaporation) during intervals of limestone deposition. The UFF lakes developed in a relatively wet climate zone without significant episodic closure due to climatically induced water deficit. Lithologic patterns within the UFF cyclothem are primarily attributed to the evolution of anastomosed fluvial systems controlled by subsidence in an active foreland basin rather than to short-term climatic change or eustacy.

Clinical cardiomyoplasty: Review of the ten-year United States experience

Clinical trials of dynamic cardiomyoplasty were pioneered at Allegheny General Hospital beginning in September 1985. Data from 9 years of experience with the procedure at this institution and more recent data from newer cardiomyoplasty centers have been analyzed for outcome analysis and future trends. Each patient underwent a cardiomyoplasty procedure using the left or right latissimus dorsi muscle. Thirty-four patients were studied at Allegheny: 5 patients implanted with dual chamber pacemakers as single stimulus myostimulators, 11 patients composing the phase I Food and Drug Administration trial of the Medtronic burst myostimulator, and 18 patients entered in the phase II Medtronic trial. Patients from seven additional centers entered the phase II trial in 1991. Fifty-seven patients completed follow-up studies to 1 year after operation in this trial. Operative mortality was 5/57 (11%) in the American phase II group and 5/34 (15%) in the Allegheny group (1/18, 6% for Allegheny phase II). Nineteen patients (19/57, 33%) from the combined phase II population died in the first year, and 10/34 (29%) in the Allegheny study. The predominant cause of postdischarge death was arrhythmia (12/19, 63% American; 7/10, 70% Allegheny). In all groups significant improvement was seen in quality of life and functional class. Phase II patients demonstrated significant increases in ejection fraction and stroke work. Failure to sustain improvement and arrhythmia-related death are complex challenges for this procedure; however, realistic solutions have been proposed and are under investigation.

Subsurface Definition of the Allegheny Group Coalbed Methane Prospect Interval in Southwestern Pennsylvania and New Gas Content Results: ABSTRACT

A preliminary reconnaissance of coalbed methane gas content data from exploratory coal cores and pre-existing data implies that the greater the depth and rank, the greater the total and cumulative gas content. The coal seams studied, ranging in age from the Pennsylvanian-Permian Dunkard Group to the Middle Pennsylvanian Allegheny Group, are from the Main Bituminous Field and two of the anthracite fields. Consequently, the Pennsylvania Geological Survey and the West Virginia Geological and Economic Survey conducted a mapping investigation to evaluate the regional geology of the coal-bearing intervals and its influence on coalbed methane potential. Phase I of this study involved the entire Pennsylvanian coal-bearing interval; Phase II focused on a stratigraphic delineation and evaluation of Allegheny coalbeds and associated sandstones. A variety of cross sections and isopach maps show several prospective coalbeds and facies relationships with channel-fill sandstones. This suggests that some of these sandstones may be traps for coalbed methane. Often overlooked in reservoir characterization is the quality of a coal seam. Coal rank, grade, and type influence the reserves and production of coalbed methane; the higher the rank, the greater adsorptive capacity of the coal. The integration of coal quality with other critical tools of exploration maymore » increase the success rate of finding {open_quotes}sweet spots.{close_quotes} Additional Pennsylvania Geological Survey drilling occurred in Beaver, Lawrence, Somerset, and Washington counties. Gas contents were graphically displayed against depth, thickness, and time for a variety of samples from 21 coal seams; average gas composition and Btu values were determined for selected samples.« less

Late Pennsylvanian climate changes and palynomorph extinctions

A major floral change occurs in the Upper Pennsylvanian strata in the Midcontinent, Illinois basin, and in the northern Appalachian basin of eastern United States. Lycospora spp. (derived from arborescent lycopsids) became extinct along with some other palynomorph taxa. This investigation is concerned with the importance of this major floral change. Samples were studied from western Pennsylvania, eastern Ohio, and West Virginia (from a previous study) cover the stratigraphic interval from the Upper Freeport coal bed, uppermost part of the Allegheny Formation, to the Mahoning, Mason, Brush Creek, Wilgus, and Anderson coal beds in the lower part of the Conemaugh Formation. The floral change occurs either at or below the accepted Desmoinesian-Missourian boundary in the Midcontinent and Illinois basin, whereas in the northern Appalachians this change occurs in the lower part of the Conemaugh Formation, between the Mahoning and Brush Creek coal beds, or when the Mason is present, between the Mahoning and Mason coal beds. With the advent of late Middle Pennsylvanian time, the climate began to change from wet tropical to seasonal tropical. The Middle-Upper Pennsylvanian boundary is the culmination of this drying trend, which was marked by reduction of available water. The peat swamps are interpreted as having changed from the domed type of bog to the planar type under these circumstances. Thus, in general, the coals of the Conemaugh Formation are characteristically much thinner than those of the Allegheny Formation. This was caused by a number of factors including reduced or more seasonal rainfall, decline of arborescent lycopsids, and the increased dominance of herbaceous and fern plants. As a result, there are fewer minable coal beds in the Conemaugh Formation. The first coal bed above the extinction of Lycospora spp. is dominated by the palynomorph taxon Endosporites globiformis which is derived from a heterosporous, herbaceous lycopsid. However, Sigillaria, another arborescent lycopsid, did not become extinct at this time as evidenced by the presence of the palynomorph genus Crassispora which is derived from Sigillaria. The reason for the survival of Sigillaria is not known, but it may have been able to adapt, in a limited fashion, to some sort of specialized microenvironment. The ferns, based on palynomorph occurrence, become numerically more important throughout the balance of the Conemaugh Formation, and dominate the Pittsburgh No. 8 and Pomeroy coal beds in the overlying Monogahela Formation.