Confirmation of the upside-down drop shape theory in gravity flow and development of a new empirical equation to calculate the shape

Jin, Aibing; Sun, Hongbing; Wu, She–Ching; Gao, Yongtao

doi:10.1016/j.ijrmms.2016.12.005

Cited by 29 publications

(15 citation statements)

References 8 publications

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“…Empirical research in bulk extraction (caving and open stoping) mining methods has tended towards improvements in efficiency or mine design. Prior empirical investigations have focused on ore dilution, draw control, stability, or safe and efficient caving initiation (Matthews et al 1980;Pakalnis 1986;Rech and Watson 1994;Swart and Handley 2005;Capes et al 2007;Brunton et al 2010;Jin et al 2017). Surface subsidence, which lends itself well to empirical research due to the ease of accessibility and availability of various measurement methods, has also been extensively researched empirically (Lupo 1996;Henry et al 2004;Villegas et al 2011;Chen et al 2013;Woo et al 2013;Wettainen and Martinsson 2014).…”

Section: Empirical Research In Miningmentioning

confidence: 99%

Mining-Induced Deformation in the Malmberget Mine

2019

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The Norra Alliansen orebody of the Malmberget sublevel caving mine consists of iron ore interspersed with biotite schist and granitic inclusions. The schist is squeezed between the ore and the host rock and in direct contact with the ore along the majority of the length of the footwall. The schist exhibits high deformation when exposed to stress. SMART cable bolt roof deformation measurements are re-analyzed to draw conclusions regarding the patterns of deformation in the mine. Each bolt's head is placed at the origin of a spherical coordinate system and the radius and inclination angle between the bolt and every production blast occurring during the bolt's recorded lifetime are calculated. The deformation experienced by each instrument is investigated by comparing the long-term recorded movements with the developed geometric variables. Patterns of deformation magnitude and rate are found with respect to production-blast distance and inclination angle, instrument location, rock quality designation, and likely mining-induced stresses. Results show that deformation magnitude tends to be higher when driven by production blasting occurring on the production level above the instrumentation when accounting for the effects of distance, but average deformation magnitude for very-near production blasts tends to be higher than that for production blasts occurring directly above the instrument. Correlations also exist between the measured RQD, estimated rockmass parameters, and the measured deformation. Empirical evidence allows the identification of six scenarios which account for 91% of the recorded high-deformation-rate events. These scenarios help determine which production activities are most likely to cause high deformation rates.

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Section: Empirical Research In Miningmentioning

confidence: 99%

Mining-Induced Deformation in the Malmberget Mine

2019

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“…''Marked particles'' are often used in physical tests to characterize the shape of the TCD (Wang et al 2015d(Wang et al , 2019aZhang et al 2018a). Marked particles refer to numbered markers (the same materials as the top coal and gangue) that correspond to unique coordinate-related information to characterize location (Jin et al 2017). Figure 10 illustrates some typical layouts of marked particles in physical tests (Wang et al 2015d(Wang et al , 2019aZhang et al 2018a).…”

Section: D Modelmentioning

confidence: 99%

“…It is an underground mining method that uses gravity to exploit massive, steeply dipping ore bodies located at a considerable depth. Many studies on top coal drawing mechanisms often use gravitational flow in block caving for reference (Wang et al 2015d;Jin et al 2016Jin et al , 2017Song et al 2018;Song and Konietzky 2019). This study reviews and summarizes of top coal drawing mechanisms in LTCC excluding those based on gravitational flow in block caving.…”

Section: Introductionmentioning

confidence: 97%

Drawing mechanisms for top coal in longwall top coal caving (LTCC): A review of two decades of literature

Wang

Yang

Wei

et al. 2021

Int J Coal Sci Technol

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This review details the state of the art in research on top coal drawing mechanisms in Longwall top coal caving (LTCC) by examining the relevant literature over the last two decades. It starts with an introduction of the brief history and basic procedures of LTCC. The framework of research on the drawing mechanism, basic concepts, and some theoretical models of LTCC are detailed in sect. research framework of top coal drawing mechanism. The authors note that the Top coal drawbody (TCD), Top coal boundary (TCB) and Top coal recovery ratio (TCRR) are key factors in the drawing mechanism. The Body–boundary–ratio (BBR) research system has been the classic framework for research over the last 20 years. The modified Bergmark–Roos model, which considers the effects of the supporting rear canopy, flowing velocity of top coal, and its shape factor, is optimal for characterizing the TCD. A 3D model to describe the TCB that considers the thicknesses of the coal seam and roof strata is reviewed. In sect. physical testing and numerical simulation, the physical tests and numerical simulations in the literature are classified for ease of bibliographical review, and classic conclusions regarding the drawing mechanism of top coal are presented and discussed with elaborate illustrations and descriptions. The deflection of the TCD is noted, and is caused by the shape of the rear canopy. The inclined coal seam always induces a larger TCD, and a deflection in the TCD has also been observed in it. The effects of the drawing sequence and drawing interval on the TCRR are reviewed, where a long drawing interval is found to lead to significant loss of top coal. Its flowing behavior and velocity distribution are also presented. Sect. practical applications of drawing mechanisms for LTCC mines 4 summarizes over 10 cases where the TCRR of LTCC mines improved due to the guidance of the drawing mechanism. The final section provides a summary of the work here and some open questions. Prospective investigations are highlighted to give researchers guidance on promising issues in future research on LTCC.

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“…Researchers have been trying to model the flow of material and how it can impact the production in cave mining for almost three decades. Numerical models [1,4,5]; pilot tests [6,7] and full scale experiments [8][9][10] have been used to study the flow of the material. Pilot models have many limitations and in most cases cannot describe the behavior of the flow.…”

Section: Firouz Khodayari and Yashar Pourrahimian*mentioning

confidence: 99%

Production Scheduling in Block Caving with Consideration of Material Flow

Pourrahimian¹

2017

AMMS

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Block-cave mining has become more popular in the last few years and the trend is expected to continue. The operating costs in this mining method could be as low as foropen-pit mining; however, production scheduling for such an operation is complicated, mainly because of the production uncertainties resulted from the material flow. The material flow uncertainties should be considered in the production schedule to be able to achieve a realistic mine plan. This research uses stochastic optimization for production scheduling in block-cave mining; the proposed model maximizes the net present value of the mining project while minimizing the production-grade deviations from a target grade. Some scenarios are considered to capture the material flow uncertainties. Testing the model for a real case block-cave mining operation shows that the proposed model can take the material flow uncertainties into the production schedule to achieve more reliable plans; the optimum production schedule is accomplished based on different scenarios which can happen in the real operations. The model also calculates the optimum height of draw as part of the optimization.

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Confirmation of the upside-down drop shape theory in gravity flow and development of a new empirical equation to calculate the shape

Cited by 29 publications

References 8 publications

Mining-Induced Deformation in the Malmberget Mine

Mining-Induced Deformation in the Malmberget Mine

Drawing mechanisms for top coal in longwall top coal caving (LTCC): A review of two decades of literature

Production Scheduling in Block Caving with Consideration of Material Flow

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