Deep Open Pit Mines Research Articles

An analytical approach for evaluation of conveyor exit strategies in open-pit mines

Transportation is the most expensive task in deep open-pit mining operations. An In-Pit Crushing and Conveying (IPCC) system, as an alternative to the conventional shovel-truck system, requires precise planning to avoid wasting high capital expenditures on trucks. The decision to fit a conveyor system into the pit design is challenging and needs to be addressed in the literature. Further optimisation of the IPCC system requires choosing an appropriate conveyor exit strategy. Conveyor exit schemes include a Dedicated Ramp Slot (DRS), an Existing Ramping System, an inclined tunnel and High-Angle Conveyors (HAC). This paper provides an analytical approach to compare the cost of different conveyor exit strategies in open-pit mines. The results indicate that for a depth up to 100 m, the Present Value of Cost (PVC) for the DRS is the least. For the cases deeper than 300 m, the HAC has the least PVC. Sensitivity analysis showed that for the depths between 100 and 300 m, a more accurate and detailed definition of parameters is needed. Besides, in most cases, the HAC provides the lowest payback period and the highest internal rate of return among the alternatives.

Multi-criteria analysis of deep pits sustainable development strategy

Relevance. Long periods of development of steeply dipping deposits necessitate multiple adjustments of mining and technical system throughout an open pit life cycle. The decisions made determine the development strategy of a mining enterprise for a long period. The complexity of making such strategic decisions depends on numerous influencing parameters. These parameters have a different impact, have a variety of units of measurement, target values, and are not only quantitative but also qualitative. There is a need for new approaches to the choice of development strategy of the mining and technical system of an open pit, as well as its main subsystem – the opening-up of an opencast system. It is proposed to base these approaches on multi-criteria decision-making methods that consider many influencing parameters. Aim. Development of a methodology for choosing a strategy for sustainable development of the deep open pit mining and technical system based on multi-criteria decision-making methods and assessment of the opening system parameters. Objects. Mining enterprise, mining and technical systems, opening system. Methods. Literature review, system analysis, multi-criteria decision making. Results. The authors have determined the main strategies for development of the mining and technical system for deep open pits. These strategies aim at achieving the sustainable development of the mining and technical system: adjustment of the current stage mining parameters; transition to a new stage of mining; transition to a combined open-underground mining; mine closure. The key role of the opening system in the structure of the mining and technical system is substantiated to ensure its sustainable development. The authors systematized the main parameters for evaluating the pit opening system and set target values for each parameter. A review of the main multi-criteria decision-making methods used to solve various problems in the mining industry is made. A rank coefficient is proposed for choosing the mining and technical system development strategy. The calculation of this coefficient is based on a combination of the fuzzy AHP and CRADIS multi-criteria methods. A method was developed for selecting a strategy for sustainable development of the mining and technical system of deep open pits. A case study was conducted on the conditions of the Maly Kuibas open pit. The obtained results strongly suggest that the best strategy with the highest ranking is the transition to the combined development method.

Комплексный анализ результатов мониторинга устойчивости уступов карьера с использованием геофизических методов исследования

The Response to challenges related to safety in open-pit mining of mineral deposits is based on continuous monitoring of the pit wall stability as a whole as well as the stability of problematic areas of the pit wall and individual benches. Control of the geomechanical state of the adjacent rock mass using local geophysical methods plays an important role in the overall monitoring of stability of the open-pit elements. The control allows studying in more detail the state of benches and groups of benches in critical areas of the open-pit and developing measures to ensure production safety on this basis. One of the main interdependent factors affecting the pit wall stability is, on the one hand, the size of the disturbed zone that depends on both natural and mining-induced rock fracturing; on the other hand, the level of ground water changing over time depending on the season. The importance of joint account of the factors above has stipulated to propose a comprehensive methodical approach to study water saturation and structural disturbance of rocks in the wall of a deep open-pit. The method consists in periodic, seasonally synchronized, geophysical studies using seismic profiling and GPR sounding and allows identifying the areas of high water saturation and disturbance in the adjacent rock mass. The methodological approach makes it possible to estimate the effect of the main time-varying impact factors (water saturation, natural and mining-induced disturbance, anomalies of physical properties of the rock mass) on the slope stability and provides a scientific and technical basis for developing engineering measures to improve the safety of deep open-pit mining.

Effect of geometric parameters of a restraining embankment on the stabilization of a deep open-pit mine excavation

Effect of geometric parameters of a restraining embankment on the stabilization of a deep open-pit mine excavation

A new model for the economic impact assessment of large-scale and deep open-pit mines

ABSTRACT This study focuses on examining economic impacts associated with deep and large-scale open-pit mining operations, which are often neglected in environmental impact assessments. Using Z-Fuzzy Delphi AHP and scenario-based techniques, 28 economic impacts were classified into seven categories and evaluated for the Sungun Copper mine in northwest Iran. Results indicated that socioeconomic factors had the highest weight (21.4%), while monetary factors had the lowest weight (7.5%). The economic sustainability score for the SCM was calculated to be 2.111, indicating poor economic performance. This research highlights the importance of considering economic impacts in mining operations for sustainable development.

Influence of Recirculation Flow on the Dispersion Pattern of Blasting Dust in Deep Open-Pit Mines.

The recirculation within a deep open-pit mine is a significant factor contributing to the deterioration of the atmospheric environment. However, the underlying mechanisms of how recirculation influences the dispersion pattern of dust clouds within the deep open-pit mine have not been clearly elucidated. In this research, the dispersion patterns of blast dust clouds were investigated in a deep open-pit mine located in northern China. This research initially conducted a similar experiment to verify the existence of recirculation flow in the experimental mine, which can cause dust particles to aggregate toward the upwind slope. In response to the dust pollution issue in deep open-pit mine blasting operations, this study conducted a numerical simulation analysis based on on-site measurement data to investigate the effects of varying natural wind velocity, natural wind direction, and blast location on the diffusion pattern of blasting dust. The results indicate that natural wind velocity (v), natural wind direction (α), and blast location (d) affect the distance between the blast location and the recirculation center point (Drecir), subsequently influencing the diffusion pattern of blasting dust. The recirculation flow effect influences the diffusion of dust toward the upwind slope under smaller Drecir values, leading to widespread and long-term pollution within the mine. Under larger Drecir values, dust diffuses toward the downwind slope with the straight flow of wind, resulting in less pollution within the mine. Through orthogonal experiments, the equation Drecir = -120.61v2 + 237.27v + 0.82d - 0.07α2+ 6.75α + 151.08 was established in this deep open-pit mine, which provides a basis for predicting the diffusion pattern of blasting dust and control strategy in this deep open-pit mine.

Developing a new social impact assessment model for deep open-pit mines

Various open-pit mines, particularly porphyry copper mines, are anticipated to reach depths of more than 1000 m, and short knowledge of social impacts at such depths is a significant challenge for the mining industry's future. In the present study, 37 social impact factors of deep open-pit mines are recognized as the first step for a Social Impact Assessment procedure. As a 37 × 37 matrix for weighting the importance level of each factor will be complicated and unreliable, these factors are classified into 10 categories and weighted using the Z-Fuzzy Delphi AHP technique. 26 experts worldwide were recognized as qualified for the study, among which 14 questionnaires were returned. The Cronbach coefficient was calculated to check the level of uniformity of the questionnaires, and the value was determined to be 0.925 for I (Importance) and 0.911 for R (reliability), which shows a high level of uniformity in the expert's predictions. By applying Z-numbers, and using fuzzy Delphi mathematics, the uncertainty of the experts' opinions was highly reduced. The results showed that the most critical social impact categories in deep open-pit mines are workplace safety (13.8%), employment (10.9%), and revenue generation (10.7%). Next, the social impact factor's score was determined using the scenarios described in this study. Finally, the methodology was applied to the Sungun Copper Mine (SCM) in the northwest of Iran for verification. The Social Sustainability Score (Ss) for the SCM was determined to be 6.364, which shows a medium level of sustainability. Finally, the proposed methodology can be used to determine the social responsibility level of any metal mining project.

Speed Sensor-Aided Navigation Filter for Robust Localization in GNSS-Denied Mining Environments

<h3>Abstract</h3> The automation of mining haulage vehicles has great potential in terms of safety and economy. The performance of autonomous vehicles depends largely on highly accurate vehicle state information. Deep mines are especially challenging, as satellite-based localization methods are reaching their limits. Therefore, we introduce a new navigation filter concept for the precise and robust localization of the haulage fleet that can handle temporary GNSS interruptions in deep open-pit mines. The multi-sensor navigation filter utilizes an inertial measurement unit and is aided by GNSS. We introduce a new optical speed sensor update within the tightly coupled unscented Kalman filter. The speed sensor measures the slip-free two-dimensional speed above ground. The filter was validated with an articulated dumper in a gravel pit. The new filter achieved a mean position error of 0.24 m during a test drive of 190 s with a simulated GNSS outage of 90 s.

Technology of an open pit refinement under limit stability of sides

Purpose. To establish the feasibility of refining deep open-pit mines below the boundary of the use of combined motor-conveyor transport with an increased slope angles of the pit walls using the developed transport unit for reloading rocks to overlying horizons during the reactivation of pillars under transport berms. Methodology. Preparation of a digital block model of the deposit, the elaboration of 3D geomechanical models for the dynamics of mining, 2D and 3D numerical simulation of the rock stress-strain state of the outcrops of opencast workings, mathematical modeling of stepwise ore reserves and mining schedule, patent research and feasibility study. Findings. It is advisable to carry out mining in terms of the marginal rock state with an increase in the slope of the pit sides below the limit of application of the cyclic and continuous method in ultra-deep open pits. Such design of pit sides is achieved when benches are mined from top to bottom within the boundaries of steeply inclined layers with the use of inter-bench loaders of the developed designed in the completion zone. Provisions for the selection and feasibility of using the loader in the deep zone are formulated based on demarcation of application zones of cyclic (road transport) and cyclic-flow (combined road-conveyor transport) technologies. Originality. Schematization of the mining operation was performed based on the calculated values of safety factor of sides, which allows increasing the slope angles of the pit walls of even ultra-deep open pits in the completion zone. It was found that with deepening of mining, the zones of potential sliding move away from the loose overburden to lower ore benches closer to the final depth of the Kacharsky open pit (760 m), but the safety factor corresponds to the required value according to the design standards. Practical value. An increase in the slope of the pit walls in the completion zone can be achieved using the developed loading installation, the main difference of which is that it can be moved without dismantling under conditions of reactivation of transport pillars (with an increase in lifting height by 1.54.5 times compared to the known equipment).

Substantiation of parameters and efficiency of sandwich belt high angle conveyors for deep open pit mines

The article focuses on substantiation of such parameters of heavy-duty sandwich belt high angle conveyors as the belt width to ensure operation without spillage of load, and the hugging pressure with regard to its dependence on the angle and length of the conveyor. It is noted that incorrect estimation of these parameters can lead to the redistribution of forces between the conveying and hugging belts with increasing load applied on the conveying belt. The economic efficiency of the high angle conveyors is considered in comparison to the traditional belt conveyors. It is shown that the cost of a traditional belt conveyor jumps with the increasing height of hoist. It is shown that the operating costs of the sandwich belt high angle conveyors increase almost linearly with an increase in the hoisting height and very slightly depend on the conveyor angle.

Обоснование оптимального уклона крутонаклонных автосъездов для полноприводных автосамосвалов, эксплуатируемых при доработке алмазорудных месторождений

At present, the design depth of open-cast diamond (kimberlite) mines is increasing through introduction of advanced technologies and new mining and transportation equipment. In 2008-2012 the Yakutniproalmaz Institute and the Institute of Mining developed scientific and methodological principles and design solutions for development of the Udachny and Botuobinsky deep open pit mines using steeply inclined ramps and the CAT-740B articulated dump trucks with the capacity of 39.5 tons. Research was conducted to determine the rational slope for articulated dump trucks in the Udachny open pit and to develop guidelines for safe operation of such dump trucks on steep inclines. The performed experiments demonstrated the ability of articulated dump trucks to safely haul rocks with loads that were close to the nominal capacity using ramps with the slope gradients up to 24% in various weather conditions. In spite of a sufficiently large number of studies on justification of parameters of developing deep open pit levels, many questions still require additional research. This is primarily explained by the limited experience of operating articulated dump trucks in Russian deep open pit mines. In this context, the issue of justifying the optimal slope gradients for all-wheel drive models of motor vehicles remains relevant. The authors of the article have analyzed the existing normative documents and methods to determine the rate of longitudinal slopes. As the result of the study, the physical criterion of the least action is proposed as the optimization criterion for the slope gradients of the in-pit roads when operating all-wheel drive dump trucks.

Investigation on flow field characteristics in an open-pit coal mine.

In this paper, the atmospheric flow field characteristics in a deep open-pit mine are investigated numerically and theoretically. A theoretical model on the recirculation length based on the energy equation is used, and a total variation diminishing (TVD) difference scheme with second-order accuracy is used to solve the NS equations with a standard two-equation k-ε turbulence model. The effects of elevated inner dump on the flow field characteristics of the open-pit mine are analyzed detailedly with the same inflow parameters. The results show that a recirculation zone exists in the open-pit mine due to the reflux from the high-pressure zone to the low-pressure zone. As the height of the inner dump increases, the flow becomes more complicated, and the low-pressure zone and the recirculation zone become bigger. The elevated inner dump makes it difficult for the internal fluid to flow to the outside, which results in the increase of the dust concentration. At last, the influences of key parameters on flow filed are conducted by normalizing the depth of the lowest direct current flow on the windward slope. The sensitivity analysis is done by study each influencing factor. This paper offers an effective way to study the flow field characteristics in an open-pit coal mine, which is essential to the dust pollution control of open-pit mine.

Economic evaluation of materials handling systems in a deep open pit mine

Economic evaluation of materials handling systems in a deep open pit mine

Economic evaluation of materials handling systems in a deep open pit mine

Economic evaluation of materials handling systems in a deep open pit mine

Computational tools for the analysis of circular failure of rock slopes

Among other types of failure in slopes created by excavation or filling, circular (also referred to as rotational) type of failure plays an important role in the design and stability analysis of high rock slopes, such as those encountered in deep open pit mines. When a rock slope of significant height involves predominantly one type of jointed rock mass, the scale of the problem is frequently such that the rock mass (intact rock and rock discontinuities) can be regarded as a homogeneous isotropic material. In such case, if the rock slope is unstable and collapse occurs, circular (or rotational) failure as in failed slopes in soils is also observed for the rock slope. One main goal in practical design of deep open pit mines is to determine safe inclination angles for the pit faces to be excavated to avoid failure. Computational tools for quick assessment of the stability conditions, in particular determination of factor of safety and location of the critical circular failure surface, are useful during the preliminary stages of open pit design. Among others, such tools allow the engineer to gain insight in the role that the different variables controlling the problem have in defining the stability conditions for the rock slope. This paper provides first an overview of typical numerical techniques used to assess the stability of high rock slopes. For the case of slopes in rock masses that are assumed to obey the Mohr-Coulomb or the Hoek-Brown failure criteria, the paper discusses how application of transformation rules leads the criteria to be re-casted in dimensionless form, so when these are applied to the solution of slope problems, the results (factor of safety and coordinates that define the location of the critical circular failure surface) can be summarized in dimensionless compact forms. The paper presents then computational tools in the form of dimensionless charts and computer spreadsheets for stability analysis. These are developed from numerical limit equilibrium models that use the mentioned transformation rules. Among others, the computational tools allow the concept of mechanical similarity of rock slopes to be naturally introduced. Finally, the paper presents various rock slope examples that illustrate the use of the computational tools. In these examples, results from limit equilibrium models are also compared with results obtained with full numerical analysis, in particular with finite difference models implementing the shear strength reduction technique.

The Efficient Acquisition of High-Resolution 3D Seismic Surveys for Shallow Open-Cut Mining

Although the seismic technique is becoming an increasingly popular tool for mining its use tends to be restricted to exploration. Although capable of being used to characterize active mining areas, this application has tended to be restricted to underground or deep open-pit mines as acquiring high-resolution data over extensive areas has previously been prohibitively expensive. In this paper we show examples of the impact of high-resolution survey parameters on the resulting processed datasets and describe how such datasets can be acquired in a cost-efficient manner leading to an extensive 3D seismic acquisition programme.

Safe Operation of All-Wheel Drive Articulated Dump Trucks on Large Slopes in Deep Open-Pit Mines

The analysis have been carried out for the production of all-wheel drive articulated dump trucks. The practical experience of operation of dump trucks as open-pit transport has been analyzed. The paper describes the technical characteristics of some models of articulated dump trucks of Russian and Belarusian production. The paper describes the examples of transportation of rock mass at enterprises of Russia and abroad. The paper points up the special aspects for making the organizational, technological and design decisions in the implementation of articulated dump trucks. The paper shows the experience of operation of all-wheel drive articulated dump trucks in open-pit mining. It has been established that articulated dump trucks allow to increase the efficiency of mine development at the stage of construction and commissioning of mining and processing plants, especially in geographically remote and inaccessible territories The measures have been developed for safe operation of all-wheel drive articulated dump trucks in open-pit mining at the development of deep-seated mineral deposits.To implement the program of import substitution of all-wheel drive articulated dump trucks it is necessary to perform market research to study the possible market of consumption of vehicles of this class at open-pit mining operations in order to justify the prospects for provision of the Russian production market.

Multichannel Facility for Bidimensional Measurement of Rock Block Displacements in Deep Open Pit Mines

Multichannel Facility for Bidimensional Measurement of Rock Block Displacements in Deep Open Pit Mines

SLOPE STABILITY ASSESSMENT OF THE SOUTHWEST OVERALL SLOPE OF THE QAJARAN OPEN-PIT MINE BASED ON THE GSI ROCK MASS CLASSIFICATION SYSTEM

The application of assessing the fracturing quality of rock masses based on the classification system for determining the boundary parameters of the Qajaran open-cast mine slope is substantiated. In the certain geomechanical environment, the long-term slope stability of the south-west wall of Qajaran open-pit mine based on the Geological Strength Index (GSI) classification system is estimated. A comparative analysis between the results with other well-known classification systems, such as MRMR, Q-system and RQD, and the outputs of the proposed GSI system is made. A good agreement between the results obtained from Barton’s Q-system and Hoek’s GSI classification systems is found. It is highly desirable to quantify the rock mass based on 2 and/or more classification systems (e.g. Hoek’s GSI and Barton’s Q-system) to provide much more reliable and reasonable estimates. The stability analysis of Qajaran open-pit overall slope at different scales based on the confirmed lower and upper bounds of the GSI classification system and compared with the results of the accepted stability criteria is performed. It has been shown that when there are limited input data of the jointed rock mass in the current geomechanical environment, it is expedient to use Hoek’s GSI classification system to determine the geometric parameters at different scales at the first development stage of the rock slope designs and estimate the stability of the overall slopes of deep open-pit mines based on Hoek-Brown failure criterion.

Mining technology for exploiting deep open-pit mines in Vietnam

Vietnam's open-pit mines have been exploited deeper and deeper. At the end of exploitation, the bottom of the mine is 300÷400 m lower than the sea level. Mining in the deep layers will face a series of difficulties such as seasonal exploitation, high pit bank, large amount of water mud, limited field size, increasing intensity of exploitation on each layer and the whole shore, conditions. The microclimate changes in an unfavorable direction at the bottom of the mine, etc. On the basis of the analysis of the characteristics of the deep layers, experience in exploiting at home and abroad, the article proposes a number of mining technology solutions. Appropriate exploitation at deep open mines such as: Exploiting convex banks, using transport equipment operating on high slope, water mud treatment technology and deep digging seasonally for safe exploitation to ensure mine output, efficiency and maximum resource recovery.