Open pit

Summary: In this paper, a procedure for analysis and calculation of basic statistics in structural
equation modeling is given. This research gains greater insight into the benefits of structural modeling in
surface water quality. The research shows the effectiveness of this method, its reliability and acceptability.
The model tested gave a practical original multiple regression equation for surface water quality as
a function of several parameters: biological, physicochemical and hydro-morphological, on a projected
expert sample.

Geologic conditions and design requirements around upstream Nachtigal Falls, in Cameroon, for the hydroelectric construction project on the Sanaga River dictated close control of blasting procedures with very precise geometry to obtain safe and economical excavation lines. Various techniques of pre-split blasting were used in the initial stage of all major excavations. Hole diameters for pre-splitting were 89 mm, and hole spacing ranged from 0.8 to 1m. Explosive charges varied from 1 to 7 kg per hole, and the detonating cord linear charge ranged from 12 to 60g. The contour blasting technique is aimed at controlling overbreak and improving remaining slope stability. Over-break or over-excavation needs to be controlled since its occurrence compromises the operations in terms of safety (instability in the remaining slope; loosening rocks that increase the risk for operational people; an irregular free face for subsequent blasting); and costs (need for reinforcement of the remaining rock structure through costly sustainment systems; increase in concrete volumes in civil works). This paper discusses in detail the design and field implementation of pre-split blasts successfully carried out to achieve clean vertical walls in moderately dipping, though complexly sheared and jointed gneiss. Based on the results of the experiments, we were able to design a pre-splitting pattern both experimentally and in a very cost-effective manner. It is felt that the methods developed on this project could have useful applications on other major construction projects.

In recent years, the development of the mining industry in the Republic of Kazakhstan has been accompanied by the commissioning of new underground levels for many existing mineral deposits, which were initially developed through open-pit mining. As the depth of open-pit mining increases, the volume of overburden rises sharply, making open-pit mining unprofitable due to the significant amount of additional mining work required. For this reason, most open-pit mines in Kazakhstan are transitioning to underground mining, or combined mining. Many researchers have examined the timing of this transition and have worked on optimizing it to determine the best economic efficiency and manage risks. However, there is limited information available on how to determine the optimal location for a vertical mine shaft when transitioning from open-pit to underground mining. The purpose of this study is to identify a safe location for a vertical shaft in combined mining operations. Specifically, the study assesses the impact of the open-pit mine on the selection of the mine shaft's location, considering the stress-strain state of the rock mass during combined mining methods. To address these objectives, numerical modeling of the stress-strain state around vertical excavations during combined mining was performed. The results provide a solution to the critical issue of determining the location of the mine shaft in combined geotechnology and lay the groundwork for further research on shaft placement in Kazakhstan. The novelty of this study lies in identifying the shaft location by considering the geometric shape of the open-pit mine and the depth of development.

RESUMEN: Este artículo analiza la viabilidad, planeamiento y diseño de una nueva explotación a cielo abierto de carbón en la mina La Margarita S.A., con recursos carboníferos superficiales calculados en 440.139,7 ton. Se logró dimensionar, diseñar y evaluar económicamente con tres diferentes métodos de explotación: Cortas, Contorno y Terrazas. Para el método de Cortas el Valor Presente Neto (VPN) fue de 817,5 de Contorno 518,5 y Terrazas 645,2 dado en millones de pesos ($) colombianos corrientes del 2004 y la Tasa Interna de Retorno (TIR) para Cortas: 78,33%, Contorno 34,0% y Terrazas 38,62. Estos indicadores sirvieron para seleccionar el método de Cortas, el cual fue ajustado con cierto detalle, ya que fue necesario trabajar conjuntamente dos frentes para hacerlo viable. Como valor agregado para el proyecto se hizo una evaluación general ambiental, que es de vital importancia para la explotación. Se dan recomendaciones para minimizar los impactos más importantes tales como la flora, fauna, aire, suelo, aguas. De cada una de ellas se plantean medidas ya sean de mitigación, control o prevención. Se espera que este trabajo sirva como soporte técnico -económico para el desarrollo de una nueva extracción de carbón a cielo abierto dentro de la mina La Margarita.

This course provides an introduction to the geological resources of mining, covering the initial phases from prospecting to general exploration, detailed exploration, development, and production stages. The Mining Geology Course aims to offer a comprehensive understanding of various mining methods, including surface mining, underground mining, solution mining, and placer mining, specifically designed for undergraduate students. Furthermore, the course will highlight the occurrence of mineral deposits in Ethiopia, along with specific districts that have progressed to the production phase. Additionally, the final section of the course will explore innovative technologies for the exploration and extraction of mineral deposits.

10%, postiglo povećanje vrednosti NPV za 24,77%, a optimizacijom graničnog sadržaja metala u rudi dodatno povećanje vrednosti NPV za 10,07%. Ukupno povećanje vrednosti NPV iznosi 37,34%, što je značajno poboljšanje ukupnih ekonomskih efekata u poslovnom sistemu rudarstvo-metalurgija. Ključne reči: površinski kop, dugoročno planiranje, optimizacija graničnog sadržaja, maksimizacija neto sadašnje vrednosti (NPV).

Purpose. The main purpose of the presented research is to improve the technology of rock destruction by explosion. For this purpose, new methods for creating a differentiated stressed state of a rock massif as well as for constructing borehole charges of explosives have been developed. The methods of research are to analyze of geological data on the iron-ore deposits of Kryvbass, project documentation, production data of the mining enterprises and open pits, scientific publications and their subsequent synthesis and formulation of the developed provisions. Findings. Explosive destruction of the rock massif with the use of vertical slopes of the quarry ledges, with the making of shielding slots, which are created by advanced explosion of special directional charges, as well as the reverse sequence of blasting of the borehole series, provides a reduction in the specific consumption of explosives by 15-17% and substantially increases the uniformity of rock crushing. The originality is ...

In order to improve conveying and crusher throughput performance, major open pit mines are increasingly using high energy blasting. Strict and effective controlled blasting methods are required to protect the integrity of the pit walls from the increasing energy concentration. The M'haoudatt mine lacks pre-split procedures, which has led to unstable slopes and landslides that have increased the strip ratio. In order to correct mining anomalies, this work intends to evaluate presplit practice. The aim of the work is to evaluate the pre-split performance in the M'haoudatt mine through tests carried out on one of the pit benches.

Increasing the diameter of drill holes is an option to increase the tonnage in open-pit mines. This explains the appearance of unexpected disorders during drilling and blasting, the consequences of which classically take the form of both instability in the pit walls and collapses affecting the surface. Here, the phenomena observed are located between the slopes of the M'HAOUDATT pit. The disorders inherent in large-scale mining appear on the pit walls. The company operating the pit exploits the benches only with large diameter drills. The objective of this work is to find an optimal method to minimize the effects of the vibration of the blast on the pit of M'HAOUDATT in order to reward the absence of the Presplitting machines. Proposals to limit the effects of blasting were discussed in two aspects, such as reducing the tonnage of explosive in the holes or finding a way to reduce the diameter of the hole, which is considered inappropriate to create stable fronts. We conclude that it is preferable to play on the diameter of the hole and to concentrate on this direction in order to come up with a method to replace the absence of pre-splitting machines in the mine. The method of borehole diameter reduction is considered new for the pit operators. Therefore, it will not be effective in the test phases despite the relevant results after the front blasting. It is important to note the difficulties of replacing small drilling machines in open-pit mines. The implication is the efficiency of the method, the right way of execution and the training of the mine personnel.

The purpose of this research is to use back analysis for mine waste dump slope stability and to determine the causes of the landslides that occured. The research method that we use is the Limit Equilibrium Method and Probabilistic Analysis with the help of the Rocscience SLIDE2 application. In this case study, it can be seen that the slope has a 1.299 static FoS (Factor of Safety) value. This value is categorized into the safety condition FoS category on slope stability if we referring to FoS classification i.e from Read and Stacey (2009). However, in fact the landslide occur on the slope itself even has a safety FoS category. Therefore probabilistic analysis was carried out to to be follow up with back analysis for the mine waste dump slope in this case study. In the back analysis of the waste dump slope it is assumed the landslide will occur if the FoS value is 1. From the probabilistic analysis, it is found that the closest possibility for the slope landslide failure is when the cohesion and unit weight of the materials decrease to 88.97 kPa and 24 kN/m 3. This shows that the amount of water pressure from the recharge area that supply the slope body can reduce the strength and the slope factor of safety. The material cohesion (c) is reduced by 9.54 % and increase the material unit weight value by 3.52 %.

The purpose of this research is to use back analysis for mine waste dump slope stability and to determine the causes of the landslides that occured. The research method that we use is the Limit Equilibrium Method and Probabilistic Analysis with the help of the Rocscience SLIDE2 application. In this case study, it can be seen that the slope has a 1.299 static FoS (Factor of Safety) value. This value is categorized into the safety condition FoS category on slope stability if we referring to FoS classification i.e from Read and Stacey (2009). However, in fact the landslide occur on the slope itself even has a safety FoS category. Therefore probabilistic analysis was carried out to to be follow up with back analysis for the mine waste dump slope in this case study. In the back analysis of the waste dump slope it is assumed the landslide will occur if the FoS value is 1. From the probabilistic analysis, it is found that the closest possibility for the slope landslide failure is when the cohesion and unit weight of the materials decrease to 88.97 kPa and 24 kN/m 3. This shows that the amount of water pressure from the recharge area that supply the slope body can reduce the strength and the slope factor of safety. The material cohesion (c) is reduced by 9.54 % and increase the material unit weight value by 3.52 %.

In this paper, an interactive planning and scheduling framework are proposed for optimising operations from pits to crushers in ore mining industry. Series of theoretical and practical operations research techniques are investigated to improve the overall efficiency of mining systems due to the facts that mining managers need to tackle optimisation problems within different horizons and with different levels of detail. Under this framework, mine design planning, mine production sequencing and mine transportation scheduling models are integrated and interacted within a whole optimisation system. The proposed integrated framework could be used by mining industry for reducing equipment costs, improving the production efficiency and maximising the net present value.

Rock slope faces typically comprise assemblages of benches intended to catch dislodged rock debris, channel groundwater and rainfall runoff along slope faces, and flatten overall slopes to design angles. Excavation of neat design-width benches is often not achieved as planned. If bench widths are reduced by adverse structure and/or poor blasting, or if their surfaces lack the required gradients for water flow and discharge at selected locations, runoff cascades over bench crests. If sufficient geological defects data exist, then risk of partial to entire bench height and akin berm width instabilities can be statistically quantified. These risks are often rock-type and slope-facing direction-dependent. In existing pits, such risks can also be estimated either by stereo-pair slope photography done from suitable vantage points around the pit or by drone flyover inspection of slope faces, but single-and multiple-event (i.e. progressive failure) structural, and poor blasting, failures are often difficult to distinguish and quantify. Water runoff over bench crests often occurs along major faults and zones of weak ground. Such discharge erodes geological defects to establish narrow slots that rapidly enlarge and coalesce into major V-shape chasms on slopes; with voids at some mines being 150 m along strike, 80 m deep and 300 m high, and with their debris runout exceeding 100 m. To avoid chasms, preventative measures are installed at time of bench mining. Remedial works are undertaken after some erosion occurs. The management decision to install preventative measures is dictated by site-specific experience and based on good appreciation of the safety and mining consequences if slope void development is not prevented. Reinstating bench drainage across large chasms is impossible; water needs diversion around such chasm footprints. Once established, considerable ongoing remedial effort is required to arrest or to retard the rate of chasm expansion. Stability monitoring alone does not solve the problem, but does provide safer working conditions. Examples of defect-controlled bench stability risks are presented. The stability impact of water runoff erosion is illustrated by examples from Australian and overseas mines. The general decision process, use of risk matrices, advantages, disadvantages, and the durability, difficulty and timing of water erosion preventative (geotextile on bench faces and high-density polyethylene, mesh with shotcrete in water drains) and remedial works (void rock backfill, toe buttress, gabion basket wall, pit floor bund and slope cutback) are discussed.

Rock slope faces typically comprise assemblages of benches intended to catch dislodged rock debris, channel groundwater and rainfall runoff along slope faces, and flatten overall slopes to design angles. Excavation of neat design-width benches is often not achieved as planned. If bench widths are reduced by adverse structure and/or poor blasting, or if their surfaces lack the required gradients for water flow and discharge at selected locations, runoff cascades over bench crests. If sufficient geological defects data exist, then risk of partial to entire bench height and akin berm width instabilities can be statistically quantified. These risks are often rock-type and slope-facing direction-dependent. In existing pits, such risks can also be estimated either by stereo-pair slope photography done from suitable vantage points around the pit or by drone flyover inspection of slope faces, but single-and multiple-event (i.e. progressive failure) structural, and poor blasting, failures are often difficult to distinguish and quantify. Water runoff over bench crests often occurs along major faults and zones of weak ground. Such discharge erodes geological defects to establish narrow slots that rapidly enlarge and coalesce into major V-shape chasms on slopes; with voids at some mines being 150 m along strike, 80 m deep and 300 m high, and with their debris runout exceeding 100 m. To avoid chasms, preventative measures are installed at time of bench mining. Remedial works are undertaken after some erosion occurs. The management decision to install preventative measures is dictated by site-specific experience and based on good appreciation of the safety and mining consequences if slope void development is not prevented. Reinstating bench drainage across large chasms is impossible; water needs diversion around such chasm footprints. Once established, considerable ongoing remedial effort is required to arrest or to retard the rate of chasm expansion. Stability monitoring alone does not solve the problem, but does provide safer working conditions. Examples of defect-controlled bench stability risks are presented. The stability impact of water runoff erosion is illustrated by examples from Australian and overseas mines. The general decision process, use of risk matrices, advantages, disadvantages, and the durability, difficulty and timing of water erosion preventative (geotextile on bench faces and high-density polyethylene, mesh with shotcrete in water drains) and remedial works (void rock backfill, toe buttress, gabion basket wall, pit floor bund and slope cutback) are discussed.

With the application of contour blasting's, we manage to make the cutting of the rock mass in the designed line, forming safe benches and slopes, which can resist for a very long time without collapsing and changing their shape. The choice of optimal parameters of the geometry of contour drillings and production drillings enables very good cutting of the rock mass and enables us to have a very good fragmentation of the rock mass, which enables us to make loading and haulage of the rock without any problems. As the optimal parameters of contour drillings and production drillings, for our case are ac= 0.75 [m], bc = 2.8 [m], dhc= 76 [mm], a=2.8 [m], b = 2.8 [m], W = 2.8 [m] dhe dh = 89 [mm].

Criteria or transition indicators to guide the complex decision problem of open pit to underground (OP-UG) transition are currently not well defined and documented as most mines rely on context-dependent experiences of their respective project feasibility teams. This problem is further compounded by the fact that transition indicators such as net present value (NPV), stripping ratio and commodity price are dynamic over time. Therefore, traditional deterministic approaches to solving the OP-UG transition problem cannot fully address the practicalities that mining companies face due to the variability of the transition indicators. This paper therefore reviews the OP-UG transition decision problem from a stochastic perspective. Transition indicators identified from an extensive literature review were used to benchmark four case study mines against one which had recently made the OP-UG transition, subsequently leading to the development of a generic OP-UG transition model for gold mines. The model indicates that depending on the type of deposit, gold mines can prepare to transition when the gold price to cost per ounce ratio is just greater than 2.0; grade is between 4 and 9 g/t, stripping ratio is between 3 and 15 m3/t and NPV is positive for the underground mining option.

Stability of waste dump is now gaining importance due to increasing depth and size of mine. Management of dump nearby mining areas is one of the most critical and crucial task for mine management due to limited land and other governing laws related to environment and forest conservation. In this paper, a study was conducted to establish the effect of slope angle on the stability of waste dump for accommodation of flyash is carried out. Based on numerical simulation, it was found that the dump slope of 60 m height with 36° slope can be critically stable with 20% flyash randomly mixed with overburden materials whereas flatter slopes provide higher factor of safety. Keeping other parameters constant, the optimum slope of 32° is the best possible to accommodate the mine dump for its long term stability. These findings were further supported by study of maximum velocity vectors and shear strain rates in every case and the extent of damage zone due to tensile pull. It is hoped that this t...

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.

Increasing the diameter of drill holes is an option to increase the tonnage in open-pit mines. This explains the appearance of unexpected disorders during drilling and blasting, the consequences of which classically take the form of both instability in the pit walls and collapses affecting the surface. Here, the phenomena observed are located between the slopes of the M'HAOUDATT pit. The disorders inherent in large-scale mining appear on the pit walls. The company operating the pit exploits the benches only with large diameter drills. The objective of this work is to find an optimal method to minimize the effects of the vibration of the blast on the pit of M'HAOUDATT in order to reward the absence of the Presplitting machines. Proposals to limit the effects of blasting were discussed in two aspects, such as reducing the tonnage of explosive in the holes or finding a way to reduce the diameter of the hole, which is considered inappropriate to create stable fronts. We conclude that it is preferable to play on the diameter of the hole and to concentrate on this direction in order to come up with a method to replace the absence of pre-splitting machines in the mine. The method of borehole diameter reduction is considered new for the pit operators. Therefore, it will not be effective in the test phases despite the relevant results after the front blasting. It is important to note the difficulties of replacing small drilling machines in open-pit mines. The implication is the efficiency of the method, the right way of execution and the training of the mine personnel.

This article involves wall control techniques, drilling practices that may lead to over break, causes of over break, and guidelines for presplitting which is the main wall control technique of discussion and possible solutions to the problem. The parameters of drilling and blasting have influence on presplitting outcomes. Those parameters are borehole diameter, explosive strength, powder factor, burden, spacing, stemming length, subgrade drilling depth, boreholes pattern, and the correspondent delay intervals. Presplitting method was used to protect wall from getting damaged due to production blasting operations at north Mara gold mine. Data collection included drilling and charging parameters specifically for presplitting both designed and actual parameters and make comparison to recognize causesof over break associated with presplitting.It has been found that the poor collaring error, uncharged pre-split boreholes and uneven staff off distance from pit wall were the main cause of underperforming pre-split in Gokona pit (North Mara) as a method of wall control. None of the pre-split borehole was drilled in the exact position as planned. Some of the boreholes were not charged for unknown reasons.Comparing actual drilled meters against planned meters to be drilled, only less than 69% was achieved.Therefore, lack of adhering of planned measurement is the main cause of unsuccessful of presplitting as a method of wall control.

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.

The aim of this study is to predict the peak particle velocity (PPV) values from both presently constructed simple regression model and fuzzy-based model. For this purpose, vibrations induced by bench blasting operations were measured in an open-pit mine operated by the most important magnesite producing company (MAS) in Turkey. After gathering the ordered pairs of distance and PPV values, the site-specific parameters were determined using traditional regression method. Also, an attempt has been made to investigate the applicability of a relatively new soft computing method called as the adaptive neurofuzzy inference system (ANFIS) to predict PPV. To achieve this objective, data obtained from the blasting measurements were evaluated by constructing an ANFISbased prediction model. The distance from the blasting site to the monitoring stations and the charge weight per delay were selected as the input parameters of the constructed model, the output parameter being the PPV. Valid for the site, the PPV prediction capability of the constructed ANFIS-based model has proved to be successful in terms of statistical performance indices such as variance account for (VAF), root mean square error (RMSE), standard error of estimation, and correlation between predicted and measured PPV values. Also, using these statistical performance indices, a prediction performance comparison has been made between the presently constructed ANFIS-based model and the classical regression-based prediction method, which has been widely used in the literature. Although the prediction performance of the regressionbased model was high, the comparison has indicated that the proposed ANFIS-based model exhibited better prediction performance than the classical regression-based model.

A rock drilling system always responds to variations in the mechanical properties of the penetrated rock mass. Combining the drill response with a detailed understanding of the drill system has the potential to give a detailed and high-resolution characterisation of the penetrated rock mass along the borehole. This paper analyses 186 boreholes, drilled using a water powered in-the-hole (ITH) drilling technique considering drill parameters; penetration rate, rotation pressure, feed pressure and percussive pressure. In addition, it suggests, calculates and uses a parameter reflecting rock fracturing. Sixty-three of the holes were filmed with a borehole camera to reveal the geo-mechanical features. The results show that the responses from the drill monitoring system can distinguish between solid rock, fracture zones, cavities and damaged rock. The ability to extract this information directly from the drilling operation provides unique prior information and can be useful to adjust production planning before charging and blasting boreholes.

In the Rembas mine pits, the coal exploitation lasts for more than one century. During this period, most of coal reserves have been mined, so there is a need for introduction the new and modern technical solutions, which will enable rationalization of exploitation, higher productivity, safety on operations and better operation conditions with lower investments. In the Rembas mine pits for coal exploitation, the low-productive pillar mining methods are used. During the eighties of the last century in some pits, the mechanized longwall mining method was applied, but the expensive equipment and complex naturalgeological conditions in the area Resava-Moravian coal basin restrict application of this metod. Bad financial situation, as well as the increasingly difficult operation conditions of exploitation, indicate a need to apply some of the methods which would be technically justified, and whose cost of exploitation would be proportional to the possibilities of mine. In this paper, the possibilities for application the shortwall mining methods are considered with their advantages compared to the previously applied mining methods in the Rembas mine.

The purpose of this study is to identify the leading causes of slope instability along a local highway in Anhui, People’s Republic of China. As part of the east expansion project, the mountain range will be excavated to create a two-way, nearly 30 m wide highway. The site’s topography consists of a hill with palm-shaped faces carved from limestone running along its sides. The geological characteristics and slope stability of the research area highlight the possibility of slope failure along both sides of the roadway. Slope stability analysis was performed in order to determine the failure mechanism and create a stable slope. Initial slope characterization and shear properties of the rock were determined by means of fieldwork and laboratory analysis. By causing wedging failure and toppling collapse, the bedding joints and discontinuity orientations increase instability, as determined by a kinematic analysis performed with DIP.6 software. The Limit Equilibrium Method (LEM) of analysis...

h i g h l i g h t s UPSH allows storing (and producing) large amounts of energy in flat regions. UPSH plants interact with the surrounding porous media exchanging water. Water exchanges influence the head difference between reservoirs. Efficiency of UPSH plants is affected by the water exchanges. Higher water exchanges improve the efficiency of pumps and turbines.

Shaft sinking is one of the main parts in underground mine planning. Shaft has various applications in underground mines e.g. minerals exiting flow, gases entrance or exit way, stope developments for exploitation etc. Considering that this section requires an abundance of expenses, management always following the election is the way that both terms have the technical considerations, economic constraints are also considered. Therefore, selecting shaft sinking method is one of the biggest concerns of underground mines management. There are some methods for this purpose including Delphi, ELECTRE, TOPSIS and AHP. This paper intends to use the combination AHP and TOPSIS methods under fuzzy environment in order to choose a ventilation shaft sinking method for Parvade mine located in coal zone of Tabas. The results indicate that RBM method is the most preferable approach, and drilling-blasting, Alimac, and SBM methods are preferred respectively.

Himalayas is one of most seismically active mountain chain in the world. Landsides and the mass wasting are a prevalent phenomenon in this region. There are a considerable number of human populations living in the hilly regions which are under a constant threat of hill slope collapse. The stability assessment of these hills is one of the vital steps to mitigate the danger to this natural calamity. The deterministic factor of safety calculations have been traditionally used for the hazard evaluation of the hill slopes. For the present study, two hill slopes, Chandaak and Chhera, have been selected for probabilistic and sensitivity analysis. These areas were analyzed using limit equilibrium method for calculation of factor of safety and probability of failure. The factors of safety were calculated using Bishop's method of slice. The analysis was done for both dry and saturated conditions. At the same time the sensitivity of each parameter on the factor of safety was analyzed. The ...

RESUMEN: La detección de microsismos debidos al movimiento de los planos de falla en un llenado artificial no es proceso trivial ni sencillo. En este trabajo se presenta una nueva metodología de detección de posibles microsismos (sismos de baja magnitud) producidos por el llenado de la corta de una mina restaurada basándose en los datos registrados por tres sismógrafos situados en diferentes puntos de la zona. Para llevar a cabo esta detección es necesario realizar un preproceso a las señales y un posterior procesado con el fin de aislar aquellos posibles eventos que puedan ser susceptibles de ser catalogados como microsismos. La metodología desarrollada permite la detección de posibles microsismos en la zona de influencia, discerniendo con acierto si los movimientos registrados corresponden a sismos originados en la zona de estudio. Gracias a los resultados obtenidos se puede concluir que la metodología resulta eficaz en su propósito.

Purpose.Development of a new procedure for calculating the density of emulsion explosives (EE), that will allow determining the detonation velocity along the charging length, depending on the inclination of boreholes during ore breaking. Methodology.A calculation method for the redistribution of EE density and mass in boreholes at different angles of inclination has been developed by using the well-known laws of hydrostatics. Measurement of the detonation velocity of the EE Ukrainit-PP-2B was conducted by using the method of polygon experimental tests. The numerical simulation of changes in the detonation velocity of explosives in boreholes was conducted by using the proposed method and established regularities. Findings.Methods of calculation of EE density changing along the charging column length under the action of hydrostatic pressure at different angles of inclination of both ascending and descending boreholes have been developed. Based on experimental data, regularities of det...

This research work assessed the Drilling and Blasting Techniques at the Granite Quarry of AFDIN Construction Company Limited, Katsina State, Nigeria. The objectives of the study were to identify drilling and blasting equipment, find out the drilling pattern and parameters, assess the blasting method and its compliance with safety practices in and around the blast site, and review the impact of the blasting operations on the surrounding environment. The concept of drilling and blasting activities and how they affect the immediate environment were examined. The study assessed quarry activities using field visits and interviews. Equipment identified at the quarry were wagon drill, jackhammer, compressors, rock breaker, excavators and tippers, etc. Also, Atlas Copco YT27 jackhammer was the main tool for hole drilling with either square or rectangular drilling pattern being adopted, and drilling dimensions of 4x5ft or 4x4ft (spacing and burden) were frequently used at the quarry. Hole depths used were 6ft, 8ft, 10ft, and 12ft and drilling bit of 1-inch or 2-inch. The study estimated that 2,088.95 kg of explosives (10% high explosive and 90% low explosive) was used to charge 2000 drilled holes with an average hole depth of 3.65metres and a diameter of 32mm respectively. A total of 7,394 tonnes of granite rock was blasted. Results from immediate blasting at the quarry indicated the presence of dust and fumes within the quarry environment and nearby villages, inhalation of which could lead to serious occupational hazards. Conclusively, explosion sound from blasting and fly-rock fragments were found to have some serious environmental and health effects on both workers and neighbouring communities in terms of noise pollution and vibration effects on structures. Dust suppression of the environment by continuous wetting of the ground and crushing process was recommended to minimise dust generation to protect workers from occupational diseases such as silicosis and Pneumoconiosis. Wearing of personal protective equipment, electric blasting method, corporate social responsibilities to the communities were also recommended.

Failure of overburden dumps is a common problem among major opencast mines across the world. In recent years, as technology advanced, the production capacity of opencast mines increased exponentially, resulting in large overburden dumps prone to hazardous mishaps. Meghahatuburu Iron Ore Mines (MIOM), with an annual capacity of 6.5 million tonnes, is currently facing similar issues with its waste dump. Slope failure in the overburden dump threatens the mine as it can bring the mining activities to a standstill. In this context, the digital surface model of the overburden dump is generated using Total Station and Differential Global Positioning Systems survey data. Further, 22 cross sections are drawn, each 50 meters (m) apart, using Global Mapper v.20 software. The factor of safety of each cross-section is calculated using GeoStudio 2019 Student Version by implementing the Morgenstern-Price method. According to the results, the calculated factor of safety ranges from 1.45 to 6.577 with cross section 7, 8, 11 and 12 showing high vulnerability to slope failure. For the prevention of spoil dump failure, these cross sections were simulated after application of nailing and anchoring. The renewed FoS was calculated and a cost-effective, optimised recommendation plan is suggested.

Ground strata failure is a major hazard for open pit mines as it has the potential to cause damage to property and can result in multiple fatalities. Slope stability radar (SSR) systems are used to continuously monitor pit walls and they can detect slope deformation to sub-millimetre scales. However, geotechnical engineers may have limited prior data to set the required trigger action response plan (TARP) thresholds. As a result, arbitrary values or data from other sites are often used to signify dangerous deformation rates which can ineffectively trigger alarms. Therefore, the primary aim of this investigation was to identify the failure indicator factors which best inform TARP thresholds at a particular mine site. Data from eight open pit failures from the same mine were analysed and then compared with data from other published failures. A secondary aim was to a develop a database of combined failure events that could be used as a reference to set meaningful TARP threshold levels ...

This handbook provides simplified cost models for evaluating underground mines. Regression analysis is used to generate capital and operating cost equations for each model in the form Y = AX B , where Y is the cost estimated and X is the assumed production capacity in tonnes per day. A and B are constants determined by the regression analysis. Equations are developed for operating costs in five subcategories: equipment operation, supplies, hourly labor, administration, and sundries. Subcategories for capital costs are: equipment purchase, preproduction underground excavation, surface facilities, engineering & management, contingency, and working capital. Cost models are developed for eight underground mining methods.

This paper determines the possible modes of slope failure, and the effect of increasing the slope angle of the Amoanda East Pit Wall of Abosso Gold Fields Limited, Damang Mine by 5 o and 10 o from 70 o because the designed slope angle (70 o) will increase ore losses at Amoanda East. The methods employed include field geotechnical mapping of the slope face, and kinematic analysis using DIPS 6.0 software to analyse the modes of failures. Based on the kinematic analysis conducted using the slope angle per design (70 o), it was found that the percentage of toppling, planar and wedge failures obtained were 20.05%, 5.41% and 0% respectively. Also, when the slope angle of Amoanda East Pit Wall was increased by 5 o (75 o) and 10 o (80 o), there was percentage increase in toppling and planar failures of (0.12 and 0.99) % and (2.59 and 4.18) % respectively, with no increment in wedge failure. Hence there is the possibility of planar and toppling failure with no wedge failure occurring at the Amoanda East. It is therefore recommended that, since the percentage increment in toppling and wedge were not significant when the slope angle was increased, the mine should continue to increase the slope angle by 5 o and 10 o from 70 o .

This research study focuses on creating a drill pattern for the Condestable mine, which will allow us to assess the percentage of dilution. For these purposes, we used the Pearse formula proposed in 1955, which allowed us to find the burden and later, the spacing that each drill hole should have in the pattern. Once we had collected all the numerical data, we used the JK SimBlast program to design the proposed drill pattern and analyze the damage zones, the tonnage acquired and the existing dilution. According the results obtained, the smaller the hole diameter, the less dilution will be generated when diversifying the wall and ceiling explosives.

The correct choice of the method of mining is of great importance, because it has a great impact on the total costs in the exploitation of mineral resources. The basic methodology for numerical ranking of mining excavation methods is the Nicholas methodology, according to which mining-geological factors of rock mass are taken into account. This choice of mining method is also called rational mining method selection. In this paper, the methodology according to Nicholas will be applied for the selection of the method of mining excavation for a specific case, according to which it was obtained that the Cut and Fill mining method is the best ranked.

Pump storage hydroelectricity is an efficient way to temporarily store energy. This technique requires to store temporarily a large volume of water in an upper reservoir, and to release it through turbines to the lower reservoir, to produce electricity. Recently, the idea of using old flooded quarries as a lower reservoir has been evoked. However, these flooded quarries are generally connected to unconfined aquifers. Consequently, pumping or injecting large volumes of water, within short time intervals, will have an impact on the adjacent aquifers. Conversely, water exchanges between the quarry and the aquifer may also influence the water level fluctuations in the lower reservoir. Using numerical modelling, this study investigates the interactions between generic flooded open pit quarries and adjacent unconfined aquifers, during various pump-storage cyclic stresses. The propagation of sinusoidal stresses in the adjacent porous media and the amplitude of water level fluctuations in the quarry are studied. Homogeneous rock media and the presence of fractures in the vicinity of the quarry are considered. Results show that hydrological quarry-rock interactions must be considered with caution, when implementing pump-storage systems. For rock media characterized by high hydraulic conductivity and porosity values, water volumes exchanges during cycles may affect significantly the amplitude of the water level fluctuations in the quarry, and as a consequence, the instantaneous electricity production. Regarding the impact of the pumpstorage cyclic stresses on the surrounding environment, the distance of influence is potentially high under specific conditions, and is enhanced with the occurrence of rock heterogeneities, such as fractures. The impact around the quarry used as a lower reservoir thus appears as an important constraining factor regarding the feasibility of pump-storage systems, to be assessed carefully if groundwater level fluctuations around the quarry are expected to bring up adverse effects. Results highlight opportunities and challenges to be faced, to implement pump-storage hydroelectricity systems in old flooded open pit quarries.

Mining is a global activity which is carried out in order to extract valuable metalliferous and non￾metalliferous materials from the earth that are processed and used in our day to day life. In mining,
proper rock fragmentation is critical in order to generate the much-needed income at low
operational costs as well as meeting of production targets. In order for the production targets to be
achieved, the fragmentation of rock should be of the required size. This is important to mining in
that it is the first step in the extraction process by reducing the size of rocks as well as loosening
them in order to be excavated effectively.
This project aims to study the effects of geological condition on blasting and the fragment size
produced by blasting, the case of Nchanga Open Pit Copper Mine in Chingola COP F. In the recent
past, production targets have not been met. This project is aimed at finding the reasons as to why
production targets have not been achieved and to offer solutions to the problem.
Among things that were investigated include the condition of the in-situ rock mass which is among
the major factors affecting the degree of fragmentation. Parameters chosen from the Rock Mass
Rating (RMR) system taken into account include; discontinuity length, strength of intact material,
spacing, weathering, separation and infilling. Geotechnical mapping was done at 145m and 165m
bench to obtain the structural RMR values of the selected site; the value of strength of intact
material was obtained through Uniaxial Compression Strength (UCS) test. After blasting, size of
blasted rock was measured using a foldable meter rule to evaluate the degree of fragmentation.
It was concluded that the major contributor to the low production is the presence geological
discontinuities such as joint and it was established that these discontinuities present in the rock
mass affect the blasting results considerably. Poorer fragmentation results from jointed rocks than
unjointed rocks because of the weakening of stress waves and the escape of gases through joints.
This was concluded after carrying out a time study as well as site observation.
It was finally recommended that a blast design having blast hole diameter of 120mm be used which
produces adequate stemming length of 1.68m that is sufficient to confine the blast energy and
prevent venting of gases in part of the blast hole compared to the 0.22m stemming length which is
not sufficient to do so. This suggested diameter also reduces the blast pattern spacing size from 4.0m to 3.0m which is capable of intercepting wedges of over 3.5m. By implementing this design,
there can be significant improvement in the fragment size distribution being obtained.
It is also recommended to use water gels instead of bulk emulsion due to the fact that water gels
contain less water as compared to emulsions hence minimizing the migration of explosive charge
or better still use plastic liners in blast holes before charging to completely prevent the migration
of bulk emulsion into rock joints

The slope stability of the Itakpe Iron Ore Mine has been carried out using computer software, ROCKPACK III. One hundred and twenty three dip and dip direction values were obtained using compass clinometer. The Itakpe Iron Ore Mine was divided into four benches; 241-258 m, 263-275 m, 276-286 m and 308-312 m. Joints along the discontinuities were mapped. The data obtained were analyzed using ROCKPACK III. The results indicate that the discontinuities within the critical zone are potentially unstable and can lead to planar failure. The Markland test carried out for wedge failure indicates that the intersection of the discontinuities does not fall within the critical zone hence there cannot be any wedge failure of the slope within the level 241-258 m. The presence of discontinuities that plot within the toppling critical zone indicates that there is potential toppling failure on the slope at the 276-286 m level. In addition, the toppling failure test shows the absence of discontinuities that plot within the toppling critical zone and this indicates the absence of potential toppling failure of the slope at the 308-312 m level. The result of the study will be useful to the management of the Itakpe iron ore mine in having a proper understanding of the failure mechanism of the slopes.

During this paper, in order to identify the priority of consideration between the problems of "mining method selection" and "determining transition depth from open-pit to underground mining" an accurate procedure is introduced step by step. First, it is essential to specify if an ore deposit that potentially will have mined by a combined method of open-pit and underground mining. In this case, optimal final open-pit limit and depth must be initially determined. After that, if the rest of deposit below open-pit limit is economically considerable, it is necessary to select the most adequate underground method with emphasis on the high production rate and low cost methods. Then, it is necessary to determine optimal transition depth from open-pit to underground mining considering a crown pillar immediately below open-pit mining. Finally, the procedure with its algorithm was used for an iron ore deposit with the combined mining potential.

Shallow ore deposits are mined by surface methods but a depth is reached in the case of most deposits after which underground methods are applied for the extraction of the remaining ore. The determination of this depth and its analysis is the subject of this paper. In order to determine transition depth from open-pit to underground mining on the basis of the allowable and economically feasible overall stripping ratios, an economic-mathematical equation is first introduced. Using the achieved equation and an analytical procedure on a particular twodimensional hypothetical tabulate deposit, an effective formula is then established. The formula introduced here, together with the procedure adopted, could be used in all similar mining situations by the mining design engineer.

cOnTROL Of denSITy And VeLOcITy Of eMULSIOn eXpLOSIVeS deTOnATIOn fOR ORe bReAKIng purpose. Development of a new procedure for calculating the density of emulsion explosives (EE), that will allow determining the detonation velocity along the charging length, depending on the inclination of boreholes during ore breaking. Methodology. A calculation method for the redistribution of EE density and mass in boreholes at different angles of inclination has been developed by using the wellknown laws of hydrostatics. Measurement of the detonation velocity of the EE UkrainitPP 2B was conducted by using the method of polygon experimental tests. The numerical simulation of changes in the detonation ve locity of explosives in boreholes was conducted by using the proposed method and established regularities. findings. Methods of calculation of EE density changing along the charging column length under the action of hydrostatic pres sure at different angles of inclination of both ascending and descending boreholes have been developed. Based on experimental data, regularities of detonation rate changing from density and charge diameter for EE UkrainitPP2B, varying according to exponential law have been established. The rational initial density of EE UkrainitPP2B has been established for ores breaking by boreholes, which is equal to 800-1000 kg/m 3 , at which the detonation rate along the length of the charge column at different angles of inclina tion of the boreholes is maintained. The obtained results will allow controlling density and detonation velocity during ore breaking. Originality. The density of EE increases in the formed charging column under the action of hydrostatic pressure: in ascending boreholes-from the face, while in descending boreholes-from the brow. practical value. Application of the calculation results of EE density at different inclination angles of boreholes makes it possible to determine in the charge column sections with its critical values more than 1410 kg/m 3 , at which a sharp attenuation of the deto nation rate begins. Consideration of this phenomenon makes it possible to prevent the occurrence of failures at the explosion of charges in boreholes during ore breaking.

In India, majority of coal demand is met by opencast mining production. The continuously increasing demand of coal has led to rapid opencast mining activities with high stripping ratio of 1:12 to 1:15, in turn requiring large quantities of overburden to be mined and its storage poses serious problem. Recently, few dump failures have taken place. Destabilisation of overburden dump hampers the production of the mine. On the other hand, under utilisation of storage capacity of the dump gives rise to additional land requirement. Therefore, for efficient functioning of dump, it is important to optimally utilise its capacity commensurate with stability. In this study, an internal dump at one of the mines of Coal India Limited has been studied. Two different techniques have been used to simulate and analyse the existing dump for its storage capacity and safety. The dump has been optimised maintaining the stability and safety requirements of the slope, and has been studied for its stability using different methods. A comparison of its factor of safety obtained from each method of analysis has been presented. From the study, an increase in the dump capacity of about 14% has been proposed by the numerical modelling technique, which further encourages possible savings in land. Hence, the paper seeks to optimise the existing dump and provide an economical and safe solution to the issues of land acquirement in India for overburden storage.

In the Rembas mine pits, the coal exploitation lasts for more than one century. During this period, most of coal reserves have been mined, so there is a need for introduction the new and modern technical solutions, which will enable rationalization of exploitation, higher productivity, safety on operations and better operation conditions with lower investments. In the Rembas mine pits for coal exploitation, the low-productive pillar mining methods are used. During the eighties of the last century in some pits, the mechanized longwall mining method was applied, but the expensive equipment and complex naturalgeological conditions in the area Resava-Moravian coal basin restrict application of this metod. Bad financial situation, as well as the increasingly difficult operation conditions of exploitation, indicate a need to apply some of the methods which would be technically justified, and whose cost of exploitation would be proportional to the possibilities of mine. In this paper, the possibilities for application the shortwall mining methods are considered with their advantages compared to the previously applied mining methods in the Rembas mine.

Stability of rock cut slopes depends upon the type of material, discontinuity attributes and geometry present in any location. Although, gravity remains the constant important factor in dictating the slope failure but other parameters like shear strength and available shear stress along the slope also decides the stability of the slopes to great extent. The strength of the material comes from the internal bonding between the mineral grains, contact between the particles and the ability of the material to respond to the stress conditions. Variation of these material attributes fluctuate the cohesion and angle of internal friction that constitutes the most important properties in defining the strength of any material. Rock resists shear stress by these two internal mechanisms. Numerical simulation by Finite Element Method technique is attempted for assessing the stability cut slope. An attempt has been made in this study to document the behavior of strength of the material in terms of...

Since 2001, the Hybrid Stress Blast Model (HSBM) project members have developed a software suite to model the complete blasting process from non-ideal detonation to muck pile formation. To preserve the physics and improve solution time, the breakage engine uses a combination of analytical models and 2D axisymmetric finite differences to model near-field crushing, coupled to 3D discrete lattice fracturing and distinct element numerical methods to model throw and muck pile development. The model has been validated by comparison with laboratory and field tests in kimberlite. Multiple blasthole simulations are used to demonstrate how changes to blasting parameters can influence downstream efficiencies. Case studies of wall control blasting show that the presplit design must balance the two opposing effects of increased damage with increased charge and decreasing attenuation of the seismic waves with decreasing charge. Modelling of decoupled explosives needs further development. Reducing...

During this paper, in order to identify the priority of consideration between the problems of “mining method selection” and “determining transition depth from open-pit to underground mining” an accurate procedure is introduced step by step. First, it is essential to specify if an ore deposit that potentially will have mined by a combined method of open-pit and underground mining. In this case, optimal final open-pit limit and depth must be initially determined. After that, if the rest of deposit below open-pit limit is economically considerable, it is necessary to select the most adequate underground method with emphasis on the high production rate and low cost methods. Then, it is necessary to determine optimal transition depth from open-pit to underground mining considering a crown pillar immediately below open-pit mining. Finally, the procedure with its algorithm was used for an iron ore deposit with the combined mining potential.