Dump Stability Research Articles

Enhancement of mechanical stability of waste dump slope through establishing vegetation in a surface iron ore mine

From the perspective of economic and safety, the mechanical stability of a waste dump is crucial; therefore, re-vegetation is considered to be the most pertinent and eco-friendly approach to achieve this goal. However, not many studies address this concern and support the type of vegetation to be carried out on these waste dump slopes. This study has, therefore, explored the possibilities of using local species for the mechanical stability of the waste dump in surface iron ore mine for long-term protection of the environment. Commonly available local species are considered as prospective candidates that can adapt quickly to the climate and fit into the ecosystem, and an in situ test was used to calculate the shear strength of the vegetated waste dump. This test used a customized shear box (0.15 m × 0.15 m × 0.15 m) to evaluate the increased mechanical stability of the vegetated waste dump on the surface iron mine. From the analysis of in situ field data, it is concluded that the mechanical stability of waste dump has significantly improved with a possibility of extending its role toward maintaining long-term stability.

Mechanical characteristics of dip basement effects on dump stability in the Shengli open pit mine in Inner Mongolia, China

For waste dump slopes that form basements, landslides can be prevented by determining a stability evolving law of dynamic development. Keeping this issue in mind, the relationship between the mechanical structure and stability of waste dumps with basements is studied. Three key factors that influence waste dump stability are presented, and judgment criteria for self-locking and unlocking states of dump basements are provided. From the friction coefficient of waste dump basement stability analyses of the Shengli open pit mine, the results indicate that waste dump basements on the right side of fault F8 and on the left side of fault F61 are subjected to self-locking. However, between faults F61 and F8, the basement is subjected to unlocking. Regarding the residual thrusting of unlocking areas, structure and stability optimization schemes for waste dumps in the Shengli open pit mine are provided through a mechanics analysis. Reducing the slopes and basement angles of waste dumps can enhance their stability by increasing basement roughness levels.

Dump Slope Stability Analysis – A Case Study

Abstract: In opencast mining operation, the stability of waste materials stands at high priority from the safety and economic perspective. Poor management of overburden (OB) dump results the instability of slope in an opencast mine. The present paper deals with the stability analysis of dump material of an opencast coal mine at Talcher coal field, Angul district, Odisha, by means of different geotechnical parameters and mineralogical composition affecting the dump slope. The prolonged rainfall in the mining area causes dump failure and loss of valuable life and property. A recent dump failure that occurred in 2013 at Basundhara mines of Mahanadi Coalfields Limited (MCL), Odisha, took 14 lives, and created problems for the mining industry. Most of the dump failure that occurs in the study area are mainly due to increase in pore water pressure as a result of rainfall infiltration. The stability of the waste dump was investigated using the limit equilibrium analysis to suggest an economical, sustainable and safe disposal of the dump in the study area.

Numerical analysis of rainfall effects in external overburden dump

The effect of slope angle for external overburden dump in response to average and heavy rainfall has been analyzed using a two dimensional finite difference method of transient water flow through unsaturated–saturated soil. The external dump stability is evaluated for five geomaterial types on the basis of globally accepted safety factor analysis technique, based on shear strength reduction approach using finite difference method. The results obtained from the finite difference method of analysis indicate that the external dump with more than 30° slope angle is greatly influenced by the rainfall under the studied conditions for geomaterial 3, 4 and 5, whereas dumps with geomaterial 1 and 2 remain safe. The analysis shows that major slope failure is out of preview for the studied rainfall conditions.

Augmenting the Stability of OB Dump by Using Fly Ash: A Geo Technical Approach to Sustainably Manage OB Dump at Jharia Coalfield, India

This paper is mainly focused over the possible utilization of fly ash along with OB dump to enhance the stability of OB dump and thus provide a sustainable approach for better waste management of both these materials simultaneously. Instability of coal mine overburden (OB) dumps is an important problem in most of the coal mines like Jharia coalfields in India. This is mainly occurring due to sliding nature of the rock material, lack of vegetation etc. Numbers of Environmental and health issues are associated with these unstable OB dumps. As it may easily flow with running water can contaminate the nearby water resource as well as carbonaceous content of the dump causes air pollution due to simultaneous combustion. On the other hand management of coal ash that is produced from thermal plants is also an important task. Dumping of fly ash in open may cause number of environmental problems.Various geotechnical and physical parameters such as particle size analysis, specific gravity, density, and friction angle/cohesion test have been performed to check the stability of OB dump and to analyze impacts of fly ash utilization to stabilize the OB dump.

Theory of calculation of the stability of slopes and bases. Stability of dumps

Theory of calculation of the stability of slopes and bases. Stability of dumps

Predictive analysis of slope stability of internal dumps in Tamnava–West field mine after flooding

The article reports the results of estimation of internal dump slope stability in flooded open pit coal mine Tamnava–West Field. The geostatic analysis of stability used methods by Bishop and Morgenstern–Price. The studies confirm that slopes of internal dump are sufficiently stable and sustain stability after drainage of the open pit.

Characterisation of overburden dump materials: a case study from the Wardha valley coal field

Recently, large-scale opencast mining activities in India have led not only to the increased generation of large volumes of overburden (OB) dump materials, but also to the transportation of huge volumes of loose geo-materials from coal faces to areas specifically designated for storing these materials in the form of external or internal dumps. The preparation of large-sized dumps is becoming a challenging task for the mining administration from two important perspectives, namely the limited availability of surface leasehold land for dumping geo-materials, and the associated problems of managing the increasing heights of these geo-structures. Normally, the assessment of stability, and taking proper steps to stabilise these external OB dumps, is a trivial task, but because of the increased risks involved with geo-hazards, the design and monitoring of such dumps is currently becoming critical for the production/operation of any mining organisation. Thus, a knowledge and awareness of the detailed nature and mechanical properties of the selected geo-materials present at these sites is becoming more important for stability assessment of OB dumps. In this study, the collected geo-materials (which are agglomerates of broken rocks and loose soil) were tested to evaluate their geotechnical parameters such as grain size distribution, soil permeability, compaction parameters, shear and normal strength characteristics, etc. These tests show that testing of geo-materials from one site is not sufficient for complete and proper site characterisation that would allow these values to be used subsequently in numerical modelling to quantify the stability of OB dumps. Therefor, it was decided that a geotechnical database for groups of geo-materials needs to be generated for the complete evaluation of OB dump stability for all mine sites in the areas of interest.

A review on dump slope stabilization by revegetation with reference to indigenous plant

The waste, subgrade ROM and fine dumps of iron ore mines are characterized by high rock fragment contents, low moisture retention capacity, higher bulk density, low nutrients, lower pH and elevated metal concentrations. Use of suitable revegetation programme, that require the selection of right type of plants to be used vis-a-vis the site condition and characteristics, can enhance the long-term stability, both mechanical and ecological, of dumps (waste, subgrade ROM and fines) through providing vegetative cover to control soil erosion and gully formation, consolidation of dump top and side surfaces, binding the loose particles through intricate roof system, etc. This paper overviews the roles of revegetation programme that can be used where vegetation is considered to be the long-term answer to slope protection and erosion control. Various revegetation processes like Coir matting, lemon grass, vetiver grass and indigenous plant may find a wide range of usage in iron ore mines for dump stabilization. The Miyawaki method of plantation is more effective than the conventional method of plantation. This will lead to co-existence of plants, and as a matter of fact each plant draws from the other vital nutrients and they grow to become strong and healthy. The Miyawaki plantation technique aims at “survival of the fittest”, and the area which undergone such plantation has an ecology of their own. The indigenous plant has good binding capacity and helps to control soil erosion as well as improve the dump stability. These indigenous plant species include Shorea robusta (Sal), Dalbergia sisoo (Shisham), Karanj and Azadirachta (Neem). The growth of indigenous plants is dependent upon the soil quality as well as the organic matter of the dump material. The leaf debris plays an important role for improving the organic matter of the dump material to successfully implement the revegetation programme.

Evaluation of dump slope stability of a coal mine using artificial neural network

Dump slope stability is critical in the design and operation of any open pit mines having significant impacts on safety and on the economics of an open pit project. The issues related to the stability of dumps is catching attention worldwide from quite some time, which is quite important for the safe working in and around monstrous structures as well as restricted availability of land. In the present paper, artificial neural network (ANN) has been used to calculate the factor of safety of dump slope of a coal mine. A three-layer, feed-forward back-propagation neural network having optimum hidden neurons is used to model. The input parameters are dump slope geometry, geotechnical properties and hydrological conditions have been used to evaluate the stability of dump slope. Six input parameters and one output parameters have been trained using various algorithms. New dump slope data sets have been used for the validation and comparison of the factor of safety of dump slope. Factor of safety has also been determined using numerical modeling technique. Results were compared between factor of safety, calculated from the numerical modeling tool and predicted value of factor of safety by ANN. It was found a very closer agreement between the predicted and calculated values of factor of safety for the dump slope with ANN over numerical modelling.

Soil and Rock Mechanics Investigations for the Assessment of Strata Behaviour of an Opencast Coal Mine

Abstract: The Singareni Collieries Company Limited (SCCL) planned for deepening the Opencast projects from the present depth of 250m to 400m. For successful operation and forecasting of strata behaviour in pre-mining was recognized. In this direction, SCCL had tie-up with CSIRO, Australia to work jointly, with a lead research provider. As part of these studies, to meet the requirement of generating needy data to conduct Numerical Modelling, extensive program was organized to take up different Physico Mechanical Properties (PMP) tests. In light of this, different tests suggested were taken up in SCCL and NIRM laboratories. The data thus generated were analyzed statistically to make use of the same for Numerical Modelling by CSIRO, Australia. The data generated during the course of organizing different tests, are synthesized and discussed in this paper. The paper deals with the methodology evolved in generation of desired soil and Rock Mechanics data to assess the stability of pit slopes, internal dump and OB dumps.

Estimate of stability of overburden dumping on an inclined surface

The author analyzes potential dumping on an inclined surface by small-capacity dump trucks. A mathematical model is developed for FEM analysis of stresses in a dump, using a proprietory method of dump stability estimation. Safe operation of dump trucks Kamatsu MOXY in such conditions is proved. The research findings are used in construction of conveyor hoist in Kachar open pit mine, Sokolov–Sarbai Mining Production Association.

Study of Numerical Simulation in Failure Modes of Waste Dump Slope

Based on the numerical simulation method and a sample slope engineer of waste dump, the failure modes of waste dump slope is analyzed. By means of analyzing working conditions such as different slope angles, single step, many steps, the failure modes of waste dump slope under different working conditions is obtained. The results show that the slope stability of multiple steps waste dump is better than the slope stability of single step waste dump, and the deformation of the slope is small.

Study of Internal Dump Stability of Dudhichua Open Cast Project, Northern Coalfields Limited, India

Dudhichua Open Cast Project is one of the prestigious projects of Northern Coalfields Limited, India; with total mineable coal reserves of approximately 400 million tonnes and corresponding 1,700 million m3 volume of waste rock i.e. overburden material. Accommodating this waste dump masses in the limited space of the de-coaled portion of the quarry is considered as one of the major challenges to the mine operators. It has been reported that this mine is facing frequent slope failures of waste rock dumps which is of great concern to the mine management in view of unsafe working condition. To tackle the above problem, a detailed investigation was carried out to propose a stable dump profile which will cater to the land economics and safety aspects of the mine. A detailed investigation along with recommendation of optimum design for dragline dump profile along with shovel-dumper-dump profile is presented in this paper.

Experimental tests for the assessment of the shear strength of marble waste dumps

The large dumps of waste material called ravaneti from marble quarrying activities in Alpi Apuane basin are distinguished features of the local landscape. They are strongly heterogeneous, never compacted and frequently subject to local instabilities. The access roads to the marble quarries cross the dumps; therefore, it is concern of the local authorities to hinder such phenomena. In this respect it is of paramount importance to evaluate the shear strength of the material comprising the dumps at the proper scale. In this note, the results of in-situ direct shear and tilt tests on samples of metric size are illustrated, together with the interpretation according to a strength criterion relative to rockfills. The results of a series of lab tests on the finer fraction of the waste material are also described and interpreted. Finally, qualitative considerations on the local and global stability of the waste dumps, related to their shear strength, are reported.

Study on Limit Height and its Stability of Open-Pit Dump Based on Basement Bearing Mechanism

This paper, which combines with the actual situation of mine, discusses the limit height and stability of the dump. Based on the basement bearing mechanism and different types of topsoil thickness, a method to calculate the height of the dump is put forward. Since the topsoil of Xichuan dump belongs to the thin type (h< h1+h2), and take into account of dumping technology, the limit height is determined to be 220 meters, which exceed design level (160m). And then, using limit equilibrium method based on Geo-Slope to analyze stability of the slope. The value of slope safety factor is 1.175~1.210, which is in conformity with the basic requirement of safety. In addition, the result also provides the dependable basis for the dump expansion.

Safety Evaluation Technology for Waste Dump Landslide of Open-Pit Mine Based on Fuzzy Mathematics

In recent years, frequent waste dump landslides brought the huge losses. Now, there is no mature theory system about the research on waste dump stability, this paper puts forward a disaster evaluation method for waste dump landslide which bases on fuzzy mathematics principle, the evaluation method is convenient and practical. Firstly, we established evaluation indicator system on the basis of analyzing landslide influence factors; first grade evaluation indicators included engineering geology, hydrogeology, dumping process and other factors; second grade evaluation indicators included geotechnical properties, foundation soft rock, foundation slope, atmospheric precipitation, underground drainage, drainage facilities, dumping way, dumping order, propulsion speed, mining disorderly, blasting vibration and force majeure. Secondly, we used analytic hierarchy process (AHP) to determine the indicator weight. At last, combining with the actual situation of some waste dump and using fuzzy mathematical theory, we had the safety evaluation to waste dump landslides, the result is in good agreement with the actual situation and shows that the method is a scientific guidance to the safety management of the waste dump.

Characteristics, causes and mitigation of catastrophic debris flow hazard on 21 July 2011 at the Longda Watershed of Songpan County, China

Debris flow is a common natural hazard in the mountain areas of Western China due to favorable natural conditions, and also exacerbated by mountainous exploitation activities. This paper concentrated on the characteristics, causes and mitigation of a catastrophic mine debris flow hazard at Longda Watershed in Songpan County, Sichuan Province, on 21 July 2011. This debris flow deposited in the front of the No.1 dam, silted the drainage channel for flood and then rushed into tailing sediment reservoir in the main channel and made the No.2 dam breached. The outburst debris flow blocked Fu River, formed dammed lake and generated outburst flood, which delivered heavy metals into the lower reaches of Fu River, polluted the drink water source of the population of over 1 million. The debris flow was characterized with a density of 1.87∼2.15 t/m3 and a clay content of less than 1.63%. The peak velocity and flux at Longda Gully was over 10.0∼10.9 m/s and 429.0∼446.0 m3/s, respectively, and the flux was about 700 m3/s in main channel, equaling to the flux of the probability of 1%. About 330,000m3 solid materials was transported by debris flow and deposited in the drainage tunnel (120,000∼130,000 m3), the front of No.1 dam (100,000 m3) and the mouth of the watershed (100,000∼110,000 m3), respectively. When the peak flux and magnitude of debris flow was more than 462 m3/s and 7,423 m3, respectively, it would block Fu River and produce a hazard chain which was composed of debris flow, dammed lake and outburst flood. Furthermore, the 21 July large-scale debris flow was triggered by rainstorm with an intensity of 21.2 mm/0.5 h and the solid materials of debris flow were provided by landslides, slope deposits, mining wastes and tailing sediments. The property losses were mainly originated from the silting of the drainage tunnel for flash flood but not for debris flow and the irrational location of tailing sediment reservoir. Therefore, the mitigation measures for mine debris flows were presented: (1) The disastrous debris flow watershed should be identified in planning period and prohibited from being taken as the site of mining factories; (2) The mining facilities are constructed at the safe areas or watersheds; (3) Scoria plots, concentrator factory and tailing sediment reservoir are constructed in safe areas where the protection measures be easily made against debris flows; (4) The appropriate system and plan of debris flow mitigation including monitoring, remote monitoring and early-warning and emergency plan is established; (5) The stability of waste dump and tailing sediment reservoir are monitored continuously to prevent mining debris flows.

Orthogonal Analysis on Factors Influencing Slope Stability of Coal Gangue Dump

In order to analyze slope stability of coal gangue dump in Shanxi Zhangcun, an in-situ push-shear test was carried out to obtain the shear strength indexes of gangue dump and it has been found that soil on top of slope possesses with larger strength than that on the hillside due to natural stacking interaction. Finite element calculation was also built to find that the plastic zone of gangue dump runs through clay layer on foot of dump. This means soil condition plays an important role in slope stability. Single index and multi factors were selected for orthogonal test design. Safety factors of slope stability were evaluated according to finite element strength reduction. Multi-factor sensitivity analysis has been conducted with the result that sensitivity of density of soil, angle of internal friction, angle of slope and cohesion to safety index of slope stability are progressive reduced.

Stability analysis of the waste dump 'Ostreljski planir' of the open pit 'Bor' in a function of water quantity

Stability analysis of the waste dump 'Oštreljski Planir' was carried out using the Geostudio2007 software for critical profiles determined on 3D model of the site in Gemcom 6 software. The influence of water on the stability of dump is defined by varying the coefficient of pore water in disposed material.