scholarly journals An investigation of longwall failure using 3D numerical modelling – A case study at a copper mine

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Phu Minh Vuong Nguyen ◽  
Tomasz Olczak ◽  
Sywester Rajwa
Keyword(s):  
Numerical Modelling ◽  
Failure Modes ◽  
Longwall Mining ◽  
Underground Mining ◽  
Copper Deposit ◽  
Ore Deposits ◽  
Mining Method ◽  
Copper Mine ◽  
3D Numerical Modelling

Abstract It is well-known that the longwall mining method (with roof caving) is widely used in underground mining extraction for bedded deposits (e.g. coal) due to its numerous advantages. Generally, this method is not commonly applied for ore deposits such as copper deposit. In Poland, the longwall mining method has been tested for thin copper deposits at the Polkowice-Sieroszowice copper mine (KGHM). Various failure modes were observed during longwall operation in the 5A/1 panel. This paper aims to examine these occurred failures. To do so, an analysis has been conducted using 3D numerical modelling to investigate the failure mode and mechanism. Based on the 3D numerical modelling results with extensive in situ measurements, causes of failure are determined and practical recommendations for further copper longwall operations are presented.

scholarly journals A new automated, safe, environmentally sustainable, and high extraction soft-rock underground mining method

2021 ◽  
Vol 121 (2) ◽  
Author(s):  
A.J.S. Spearing ◽  
J. Zhang ◽  
L. Ma
Keyword(s):  
Coal Mining ◽  
Longwall Mining ◽  
Underground Mining ◽  
Soft Rock ◽  
Ore Deposits ◽  
Mining Method ◽  
Environmentally Sustainable ◽  
Continuous Miner ◽  
Percentage Extraction ◽  
Environmentally Sound

SYNOPSIS Ore deposits are becoming more complex to mine as a result of the exhaustion of surface and other easily mined deposits. There is also increasing socio-political pressure to design more environmentally sound, sustainable, and safe mining practices. Wang and Ma designed a mining method for coal, similar to a modified drift and fill using a continuous miner to take sequential cuts (rooms) that are subsequently backfilled. The authors have modified the concept to make it more autonomous, safer, and less costly using highwall coal mining techniques, modified and adapted for underground applications. The method is more flexible than longwall mining and the percentage extraction would seem to be in the same range. In addition because of the backfilling, surface subsidence would not be a major issue and could be more effectively managed. Keywords: highwall mining, underground coal mining, backfilling, backfill face stability, continuous miner, safety.

scholarly journals Field and Numerical Modelling Investigations on the Stability of Underground Strata during Longwall Workings

2021 ◽  
Author(s):  
G Budi ◽  
Kolikipogu Nageswara Rao ◽  
Punit Mohanty
Keyword(s):  
Numerical Modelling ◽  
Longwall Mining ◽  
High Capacity ◽  
Field Monitoring ◽  
Longwall Face ◽  
Mining Method ◽  
Company Limited ◽  
Extensive Field ◽  
Powered Support ◽  
The Stability

Abstract Understanding the behaviour of underground workings is essential for the success of any mining method. The longwall mining method is one of the predominant underground methods to extract coal. Since 1978, in India, 22 underground coal mines of different collieries have been implemented the mechanized longwall method. SCCL is one of that colliery has mixed working experiences with longwall method in their mines. The longwall faces in GDK-10A, JK-5, and VK-7 of SCCL had produced good results, but the faces in GDK-7, GDK-9, GDK-11A, and PVK-5 had suffered due to the geological disturbances and unavailability of real-time information about the strata behaviour. By addressing the previous experiences of longwall workings, Singareni Collieries Company Limited (SCCL) has implemented a high capacity (1 × 1152T) powered support system in Adriyala Longwall Project (ALP) at a depth of 375m. In this study, extensive field monitoring with different strata monitoring instruments was conducted in ALP to analyze the gate roads convergence, stress variation on longwall and chain pillars at different stages of extraction (i.e., 8m, 25m, 35m, and 45m) and the pressure variation on the powered support systems. It was observed from the results that the convergence in the gate roads was increasing with the advance of the longwall face and the area of exposure. The pressure of the legs on the dip side was less than the pressure of the legs on the rise side, which implies a stable roof condition over the longwall face. To better understand the behaviour of ALP workings, a numerical modelling study with FLAC 7.0 has been conducted with actual physio-mechanical properties. The computed numerical modelling results have been remarkably well in consistent with the field monitoring results. The stability of chain pillars has been estimated at every stage of extraction by the Factor of Safety (FoS) criterion and it was found that the pillars could be ensured stability in longwall workings.

Hierarchical fuzzy-AHP-based multi-criteria decision making approach for selection of underground metal mining method

2021 ◽  
Vol 15 (3) ◽  
pp. 405-420
Author(s):  
Bhanu Chander Balusa ◽  
Amit Kumar Gorai
Keyword(s):  
Decision Making ◽  
Underground Mining ◽  
Fuzzy Ahp ◽  
Hanging Wall ◽  
Ore Deposits ◽  
Mining Method ◽  
Metal Mining ◽  
Extrinsic Factors ◽  
Ore Deposit ◽  
Mining Methods

In the last few decades, many underground mining methods were proposed for extractions of ores. The decision-making for selecting the most suitable mining method for a typical ore depost depnds on various intrinsic and extrinsic factors (intrinsic – dip, shape, thickness, depth, grade distribution, RMR (rock mass rating) and RSS (rock substance strength) of ore, hanging wall, footwall, and extrinsic – recovery, dilution, safety, productivity, flexibility, capital). The present study aims to develop a hierarchical Fuzzy-AHP (FAHP) model for choosing the most suitable underground mining method for an ore deposit. The structure of the proposed hierarchical FAHP model consists of five levels. The level-1 of the hierarchy defines two variables (intrinsic factors and extrinsic factors). These are further classified into quantitative or qualitative nature of variable (listed in level-2). The criteria, sub-criteria, and mining method variables are listed respectively in Level 3, Level 4, and Level 5. For each level of the hierarchy, a fuzzy pair-wise comparison matrices are developed using the corresponding levels’ listed variables. These matrices at each level are subsequently used to determine the local and global weights of each variable. The global weights are used for prioritizing the different mining methods. The proposed hierarchical FAHP model was validated by considering the field data of two different ore deposits in India. The results showed that the most appropriate mining method predicted from the decision-making model and the adopted mining method for extracting the ore deposit are same in two case studied mines.

Ground surface subsidence as effect of underground mining of the thick coal seams in the Jiu valley basin / Osiadanie gruntów wskutek wybierania pokładów o dużej miąższości w kopalniach zagłębia w dolinie Jiu

2012 ◽  
Vol 57 (3) ◽  
pp. 547-577 ◽  
Author(s):  
Ilie Onica ◽  
Dacian Marian
Keyword(s):  
Surface Deformation ◽  
Longwall Mining ◽  
Underground Mining ◽  
Ground Surface ◽  
Surface Subsidence ◽  
Coal Seams ◽  
Elasto Plasticity ◽  
Ground Surface Subsidence ◽  
Time Dependent Analysis

Abstract In the case of the thick and gentle coal seam no. 3 of the Jiu Valley Coal Basin (Romania), the mining methods are by use of the longwall mining technologies with roof control by caving or top coal caving. In this paper, it is presented the analysis of the complex deformations of the ground surface, over time, as a consequence of the coal mining in certain mining fields of the basin. Also, it is analysed the ground surface subsidence phenomenon using the CESAR-LCPC finite element code. The modelling is made in the elasticity and the elasto-plasticity behaviour hypothesis. Also, the time dependent analysis of the ground surface deformation was achieved with the aid of an especial profile function. The obtained results are compared with the in situ measurements data basis.

3D numerical modelling of a pulsed pumping process of a large DNAPL pool: In situ pilot-scale case study of hexachlorobutadiene in a keyed enclosure

2018 ◽  
Vol 214 ◽  
pp. 24-38 ◽  
Author(s):  
Quentin Giraud ◽  
Julio Gonçalvès ◽  
Benoît Paris ◽  
Antoine Joubert ◽  
Stéfan Colombano ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Pilot Scale ◽  
3D Numerical Modelling ◽  
Pulsed Pumping

Effect of blast-induced vibrations on fill failure in vertical block mining with delayed backfill

2014 ◽  
Vol 51 (9) ◽  
pp. 975-983 ◽  
Author(s):  
Muhammad Zaka Emad ◽  
Hani Mitri ◽  
Cecile Kelly
Keyword(s):  
Numerical Model ◽  
Numerical Modelling ◽  
Numerical Simulations ◽  
Monitoring System ◽  
Ore Deposits ◽  
Mining Method ◽  
Mine Design ◽  
Typical Layout ◽  
Blast Vibrations

Numerical modelling has long been used as a powerful tool for geomechanics mine design and analysis of such problems as ore dilution. Open stoping mining method with delayed backfill is generally employed for mining steeply dipping tabular ore deposits. Several authors reported that consideration of production blast vibrations on adjacent, exposed backfill faces is crucial for the effective backfill design for minimum ore dilution due to fill failure. In this study, it is shown that blast vibrations can be characterized with dynamic numerical modelling. A FLAC3D dynamic numerical model has been developed for a typical layout of a secondary stope that is being mined next to a previously mined and backfilled primary stope. The numerical simulations are validated by comparing predicted failure geometry with laser-surveyed stope profiles obtained with a cavity monitoring system. It is shown that blast-induced vibrations can be a primary cause for wedge-type failure of the backfill face.

Numerical Modelling and Assessment of Excavation Damaged Zone around the Underground Excavations: A Case Study

2006 ◽  
Vol 324-325 ◽  
pp. 77-80 ◽  
Author(s):  
Deng Pan Qiao ◽  
Zong Sheng Zhang ◽  
Shu Hong Wang ◽  
Ya Bin Zhang
Keyword(s):  
Rock Mass ◽  
Stress Field ◽  
Numerical Modelling ◽  
Underground Mining ◽  
Rock Masses ◽  
Stress Concentrations ◽  
Anisotropic Rock ◽  
Excavation Damaged Zone ◽  
Damaged Zone

This paper presents a study on the quantification of the degree of damage from the microseismic event data, for assessment of excavation damaged zone of anisotropic rock in Jinchuan mine and presents numerical simulation and prediction on the deformation and failure of the rock masses surrounding laneway under rock mass properties and excavating conditions. Following an introduction to the engineering geology and mechanical properties of the rock mass in the Jinchuan mine areas, this paper reveals the features of the measured in situ stresses and puts emphasis on an analysis of the mechanism of underground opening and damage induced by the underground mining. Stress and AE redistribution induced by excavation of underground engineering results in the unloading zone in parts of surrounding rock masses. A micromechanics-based model has been proposed for brittle rock material undergoing irreversible changes of their microscopic structures due to microcrack growth. A systematical numerical modeling analysis method was completed. Based on numerical modelling, a series of predicting curves for rock mass response and deformation are obtained, which provides the basis of guiding the design and construction of anisotropic rock cave in Jinchuan mine. The use of the in situ stress field results in enhanced modeling of the stress concentrations and potential failures at the mines has also been reviewed. Knowledge of the prevailing rock stress field at the mines is a critical component for such modeling which has led to improved rock mechanics understanding and operations at Jinchuan mines.

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