•Data driven research based on big data is creating an existential challenge in IS research.•There is a need to move beyond “what the big data represents” to the “why it is so”.•Methodological ...adaptations have been proposed in this opinion article for theory building.•Directions are provided for grounding findings to contribute to IS discipline through theory building.•Gaps in existing approaches with guidelines for future research is proposed.
Data availability and access to various platforms, is changing the nature of Information Systems (IS) studies. Such studies often use large datasets, which may incorporate structured and unstructured data, from various platforms. The questions that such papers address, in turn, may attempt to use methods from computational science like sentiment mining, text mining, network science and image analytics to derive insights. However, there is often a weak theoretical contribution in many of these studies. We point out the need for such studies to contribute back to the IS discipline, whereby findings can explain more about the phenomenon surrounding the interaction of people with technology artefacts and the ecosystem within which these contextual usage is situated. Our opinion paper attempts to address this gap and provide insights on the methodological adaptations required in “big data studies” to be converted into “IS research” and contribute to theory building in information systems.
For twenty-five years, Kendall Brown studied Potosí, Spanish America's greatest silver producer and perhaps the world's most famous mining district. He read about the flood of silver that flowed from ...its Cerro Rico and learned of the toil of its miners. Potosí symbolized fabulous wealth and unbelievable suffering. New World bullion stimulated the formation of the first world economy but at the same time it had profound consequences for labor, as mine operators and refiners resorted to extreme forms of coercion to secure workers. In many cases the environment also suffered devastating harm. All of this occurred in the name of wealth for individual entrepreneurs, companies, and the ruling states. Yet the question remains of how much economic development mining managed to produce in Latin America and what were its social and ecological consequences. Brown's focus on the legendary mines at Potosí and comparison of its operations to those of other mines in Latin America is a well-written and accessible study that is the first to span the colonial era to the present.
The global economy threatens the uniqueness of places, people, and experience. In Here and There Bill Conlogue tests the assumption that literature and local places matter less and less in a world ...that economists describe as “flat,” politicians believe has “globalized,” and social scientists imagine as a “global village.” Each chapter begins at home, journeys elsewhere, and returns to the author’s native and chosen region, northeastern Pennsylvania. Through the prisms of literature and history, the book explores tensions and conflicts within the region, tensions and conflicts created by national and global demand for the area’s resources: fertile farmland, forest products, anthracite coal, and college-educated young people. Making connections between local and global environmental issues, Here and There uses the Pennsylvania watersheds of urban Lackawanna and rural Lackawaxen to highlight the importance of understanding and protecting the places we call home.
To improve the recovery ratio of coal resources and stress environment of the roadway, gob-side entries have been widely implemented to numerous coal mines in China. Traditional gob-side entry is ...generally excavated after the gob of the adjacent longwall face is stabilized. To achieve a balance between the seam mining and roadway excavation, numerous mine coals use the method of driving a roadway along the next gob, which heads adjacent to the advancing coal face, and maintaining a narrow coal pillar. Consequently, the dynamic pressure occurs at the gob-side entry; accordingly, the difficulty of roadway maintenance is increased. However, the traditional gob-side entry stability analysis is not applicable to a gob-side entry under dynamic pressure. In this study, the overburden structural model and coal pillar stress model of a gob-side entry under dynamic pressure were established considering the compression load of the immediate roof and gangue and influence law of the cantilever beam length of main roof. Subsequently, thickness, hardness, and deformation of the immediate roof on the stability of the gob-side entry were studied, and the theoretical criterion for the stability of “voussoir beam” structure and coal pillar of the gob-side entry under dynamic pressure were proposed. Based on the geological conditions in tailgate # 110505 of the Yushuling coal mine, reasonable measures were taken considering the aspects of roof cutting and pressure relief, coal pillar design, and surrounding rock reinforcement. After applying the proposed measures, the width of the coal pillar was reduced from 15 m to 4 m. Meanwhile, the grouting cable beam was used to strengthen the roof, and the narrow coal pillar was reinforced by a bidirectional grouting anchor cable was developed. As a result, after the roadway was stabilized, the roof-to-floor convergence and two-side convergence were 268 mm and 105 mm, respectively. Moreover, the stress concentration factor of the coal pillar was 1.20. The stability characteristics of the overburden and coal pillar of the gob-side entry under dynamic pressure were effectively controlled, and remarkable economic benefits were obtained in this coal mine. The techniques proposed for maintaining the stability of the 4 m wide coal pillar and ensuring the bidirectional grouting reinforcement have been successfully applied in a coal mine for the first time, which have high innovation and application values. This study provides a reference for the design and maintenance of the gob-side entry under dynamic pressure.
Backfill-strip mining is proposed as a sustainable mining method to address the shortage of backfill material and high filling costs at present. The overlying strata in backfill-strip mining are ...mainly supported by the combined support pillar (CSP) of the residual coal pillar and the filling body. The stability of the CSP in backfill-strip mining is important to control the surface subsidence and reduce surface environmental damage. The particle flow code (PFC) simulation method is used in this study to investigate the deformation characteristics, failure behaviours, and stress distribution of the CSP for assessing its stability. The different influencing factors of the stability of the CSP, including geological mining factors, backfilling mining techniques, and the sizes of the residual coal pillar and the working face, are discussed. The results show that the shape of the CSP looks similar to a saddle. The vertical stress of the coal pillars is larger than that of the filling body. The subsidence value of coal pillars is smaller than that of the filling body, but the horizontal movement value of the coal pillars is large. Among these influencing factors of the stability, the residual coal pillar width has the greatest influence on the CSP. The different widths of the residual coal pillar lead to changes of the support formation and the bearing stress weight of the CSP, which make a big difference in the stress distribution characteristics, the movement deformation characteristics, and the stability of the CSP. On this basis, the CSP is divided into four types according to the stability and the support characteristics of the CSP, and their deformation characteristics and stability are summarised. The research results are important for guiding the stability assessment of CSP in backfill-strip mining and preventing the subsidence disaster whilst promoting sustainable extraction of coal resources.
In this study, the effect of gradual deterioration on the long-term stability of shallow abandoned room and pillar coal mines is investigated. The conventional Tributary Area Method is adopted and ...modified to take into account the rate of deterioration on the lifetime of pillars. Moreover, a simple quantitative approach is proposed to incorporate the effects of deterioration in numerical modelling. The suggested methods are then used to assess the stability of the shallow abandoned room and pillar coal mines around Dolphingstone village, UK. Results of this study indicate that the gradual deterioration plays a significant role in the long-term stability of shallow abandoned coal mines. The stand-up time of a room and pillar mining panel is also estimated based on the modified Q-system. A good agreement is observed between the results of numerical modelling and the rock mass classification system.
•Post-mining subsidence is a challenging problem in rock engineering.•The modified Tributary Area Method (TAM) was used to estimate the lifetime of pillars.•The effects of gradual deterioration was incorporated in the numerical modelling.•The long-term stability of an abandoned room and pillar coal mine was investigated.•This study showed that deterioration plays a significant role in the long-term stability of mining excavations.
Karstic water damage is one of the main disasters that threatens safe production in coal mines. As coal mining in China moves toward deeper strata, deep karst water disasters caused by mining are ...increasingly common. This paper studies the Jiyang coal mine in Shandong Province, China; conducts an in-depth analysis of the water charging conditions of the Ordovician limestone karst aquifer; determines four evaluation indices of the Ordovician limestone water inrush risk (water yield, water pressure, geological structure complexity and effective aquifuge thickness); and establishes a multifactor model to evaluate the water inrush risk of the Ordovician limestone using multisource information fusion, the water resistance coefficient and the equivalent coefficient. In addition, the floor water inrush risk of the Ordovician limestone during caving mining, strip mining and backfilling mining of the No. 13 coal seam is evaluated in the study area, which is then divided into different zones: a safe zone, a relatively safe zone and a danger zone. According to the evaluation results, the full backfilling mining method with the minimum risk range of water inrush is selected for future mining. Using this method, most of the research area is classified as a safe zone or relatively safe zone, and only a very small area in the south is classified as a danger zone. The threat of Ordovician limestone inrush caused by coal mining is low. The evaluation results of the water inrush risk and optimization of the mining method provide a reference for the prevention and control of mine water damage and can provide guidance for safe coal mining.
We propose here a three-zone conceptual model in overlying strata of a longwall panel that accounts for the coupled behaviour of strata deformation and gas flow. The model comprises a fractured ...gas-interflow zone, a de-stressed gas-desorption zone, and a confined gas-adsorption zone. The fractured gas-interflow zone represents the area where mining-induced cross-strata fractures and bedding separations are well developed with high permeability in both the vertical and horizontal directions. Coal seam gas can easily be released from this lower zone to flow down into the mine workings. The de-stressed gas-desorption zone, which lies above the fractured gas-interflow zone, is another significant gas-producing zone in which strata are highly de-stressed. However, mining-induced fractures in this zone are mainly created in the form of bedding separations, which only increase horizontal permeability, and thus the gas cannot easily flow vertically down to the mine workings. In the upper confined gas-adsorption zone, strata depressurisation is limited; the major proportion of coal seam gas in this zone remains adsorbed and cannot be effectively captured. While both lower zones are the targets of gas drainage, the fractured gas-interflow zone is the main source of ventilation gas emission and the prime area of gas control. We have developed an approach to determine the height of these three zones based on the hypothesis of key stratum in strata movement, and verified the approach using gas drainage experience at a Chinese coal mine. The applications of the three-zone concept in selecting appropriate gas drainage methods for varied mining conditions, assessment of methane recovery efficiency, and gas drainage optimisation and maximisation in a mining district of China are also discussed.
•We characterise coupled strata and gas behaviours in multi-seam mining.•Overlying coal-measure strata are characterised into three zones.•Method of discriminating the zones is developed with key-stratum hypothesis.•The gas three-zone characterisation helps optimise coal mine gas drainage.
Recently, high utility pattern (HUP) mining is one of the most important research issues in data mining due to its ability to consider the nonbinary frequency values of items in transactions and ...different profit values for every item. On the other hand, incremental and interactive data mining provide the ability to use previous data structures and mining results in order to reduce unnecessary calculations when a database is updated, or when the minimum threshold is changed. In this paper, we propose three novel tree structures to efficiently perform incremental and interactive HUP mining. The first tree structure, Incremental HUP Lexicographic Tree (IHUP L -Tree), is arranged according to an item's lexicographic order. It can capture the incremental data without any restructuring operation. The second tree structure is the IHUP transaction frequency tree (IHUP TF -Tree), which obtains a compact size by arranging items according to their transaction frequency (descending order). To reduce the mining time, the third tree, IHUP-transaction-weighted utilization tree (IHUP TWU -Tree) is designed based on the TWU value of items in descending order. Extensive performance analyses show that our tree structures are very efficient and scalable for incremental and interactive HUP mining.
With the third innovation in science and technology worldwide, China has also experienced this marvelous progress. Concerning the longwall mining in China, the “masonry beam theory” (MBT) was first ...proposed in the 1960s, illustrating that the transmission and equilibrium method of overburden pressure using reserved coal pillar in mined-out areas can be realized. This forms the so-called “121 mining method”, which lays a solid foundation for development of mining science and technology in China. The “transfer rock beam theory” (TRBT) proposed in the 1980s gives a further understanding for the transmission path of stope overburden pressure and pressure distribution in high-stress areas. In this regard, the advanced 121 mining method was proposed with smaller coal pillar for excavation design, making significant contributions to improvement of the coal recovery rate in that era. In the 21st century, the traditional mining technologies faced great challenges and, under the theoretical developments pioneered by Profs. Minggao Qian and Zhenqi Song, the “cutting cantilever beam theory” (CCBT) was proposed in 2008. After that the 110 mining method is formulated subsequently, namely one stope face, after the first mining cycle, needs one advanced gateway excavation, while the other one is automatically formed during the last mining cycle without coal pillars left in the mining area. This method can be implemented using the CCBT by incorporating the key technologies, including the directional pre-splitting roof cutting, constant resistance and large deformation (CRLD) bolt/anchor supporting system with negative Poisson's ratio (NPR) effect material, and remote real-time monitoring technology. The CCBT and 110 mining method will provide the theoretical and technical basis for the development of mining industry in China.
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