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Reliability is widely used as a performance indicator of mining equipment to achieve a cost-effective maintenance plan. Reliability is a function of time as well as environmental and operational factors. Applying an adequate model by taking into account the mentioned factors is vital to ensure an accurate estimation of reliability characteristics. The aim of this study is to investigate the application of mixed frailty model to describe both observed and unobserved heterogeneity in reliability analysis of mining equipment. The capability of the model is assessed using field data from a fleet of dump trucks in an open-pit mine. The results indicate that the proposed model is superior to the traditional Cox model when data are heterogeneous.
Nowadays due to the existence of the economic and geological uncertainties and the increasing use of scenario-based project evaluation in the design of open-pit mines, it is necessary to find an exact algorithm that can determine the ultimate pit limit in a short period of time. Determining the ultimate pit limit is an important optimization problem that is solved to define what will be eventually extracted from the ground, and directly impacts the mining costs, revenue, choosing mining equipment, and approximation of surface infrastructures outside the pit. This problem is solved in order to maximize the non-discounted profit under the precedence relation (access) constraints. In this paper, the Highest-Level Push-Relabel (HI-PR) implement
Waste rock dumping is very important in the production planning of open-pit mines. This subject is more crucial when there is a potential of acid-forming (PAF) by waste rocks. In such a type of mines, to protect the environment, the PAF materials should be encapsulated by non-harmful rocks. Therefore, block sequencing of the mined materials should be in such a way that both the environmental and economic considerations are considered. If non-acid forming (NAF) rocks are not mined in a proper time, then a stockpile is required for the NAF materials, which later on would be re-handled for encapsulation of PAF rocks. In the available models, the focus is on either block sequencing or waste dumping strategy. In this work, an attempt has been ma
Block sequencing is of great importance in an open-pit mining operation. Sequencing is usually performed to maximize the net present value (NPV). Also, from the environmental viewpoint, the sequence of dumping mined materials is of significant value in the sulfide mines. The potential acid-forming (PAF) waste rocks in these mines can seriously damage the environment due to the formation of acid mine drainage (AMD). To prevent the exposition of the PAF materials, it is essential to design suitable block sequencing. For this purpose, encapsulation of the PAF rocks by non-acid forming (NAF) rocks should be considered during waste dumping. However, this method can impose unnecessary re-handling costs. This issue is due to the determination of t
Acid rock drainage (ARD), produced from sulfide-bearing mine waste (e.g., waste rock, tailings) at active and abandoned mine sites, continues to be a global concern due to the significant impacts on water, soil, biodiversity, and the creation of public health risks. Many examples demonstrate that it is technically challenging to control and manage ARD, with common methods including costly additive treatments. Instead, an improved approach to ARD management is to minimize opportunities for generation from the outset. In this paper, a new mixed-integer programming (MIP) model is proposed to optimize the placement of waste rock into waste dumps with the objective of minimizing ARD formation. The MIP model considers the net neutralizing potenti
In this research, a rule-based expert system, with a graphical user interface, has been designed and implemented to measure, evaluate and provide a policy of improving mining productivity corresponding to the productivity management cycle. The expert system includes a set of rules related to how to calculate and analyze the productivity gap, and the inference engine is based on the analysis of the leading rules. Major policies are being improved based on quantitative and qualitative indicators. In order to evaluate the effective variables and to determine the relative importance of these policies, a fuzzy inference system based on expert opinions has also been implemented. To evaluate system performance, data from a gold mining complex was
Loading and hauling represent an important part of open pit mines production cycle and account for a considerable share of the total operating cost. The decision making during mine planning requires suitable and quick cost models. This paper intends to develop a model for estimating the capital and operating cost of major loading and haulage equipment used in the open pit mining, applying single (SRA) and multiple regression analysis (MRA). The MRA is based on Principal Component Analysis (PCA). The equipment include classical loading vehicles including hydraulic and cable shovels, wheel loader and backhoe along with rigid rear dump truck. Cost functions are classified on the basis of cost types; ie capital and operating costs. Furthermore,
Introduction: Lifestyle is important in doing healthy behaviors by students as an important part of a community has important role. Measurement tools that are used to determine the achivment of research’s goals in each study need to be evaluated. The aim of this study was to determine the validity and reliability of a healthy lifestyle measurement scale for high school students based on the theory of planned behavior in Iran. Materials and Methods: In this psychometric study, after conducting library studies and using research in the city of Rafsanjan, the initial questionnaire designed and it was used to determine the validity of the tool by face and content validity from the views of 10 high school students and 10 experts in Health educ
Determining the transition limit from the open pit mining to an underground mining method is one of the key decisions where there is the possibility to mine using both open pit and underground mining methods. Transition level is a depth where open pit mining is the best choice above this depth and underground mining is prioritized below it regarding the technical and economic aspects. In the early-stage mine planning studies, including the determination of transition limit, simplicity, practicality, and quickness of decision making are of the requirements, while achieving the acceptable answers is regarded. In this research, a practical approach based on combining Lerchs and Grossman algorithm and the Equilibrium Stripping Ratio (ESR) metho
In the civil and mining projects, blasting operation is important from technical and economical point of view. There are several parameters which affect the result of operation such as desired fragmentation and undesired phenomena, e.g., ground vibration, fly rock, etc. From these parameters, rock mass characterizations can be considered as more influential as compared to the blasting pattern. In other words, it can be said that pattern specifications should primarily be designed according to the rock mass properties to reach the main objective of the operation, i.e., rock fragmentation. Complex nature of the problem needs to implement robust approaches such as artificial intelligence-based techniques. In this paper, an attem
From the viewpoint of safety in underground coal mining, the most suitable mining panel is the one with minimum geological structures, the right machinery, and equipment selection, trained employee, and proficient stope management. Since the ground parameters are uncontrollable and inherent uncertainties exist, a high percent of risk will usually accompany the underground coal mining activities. The main purpose of this study is to present a geological–geotechnical risk assessment model for identification of high risk-prone areas in underground coal mines using an integrated GIS-geostatistics system. Tabas as the first mechanized and largest underground coal mine in Iran was selected as a case study in this study. Gas conte
Failure mechanism of rocks is one of the fundamental aspects to study rock engineering stability. Rock is a material that contains flaws, initial damage, micro-cracks, etc. Failure of rock structure is largely due to tensile stress and was influenced by various parameters. In the present study, the effect of brittleness and loading rate on the physical and mechanical phenomena produced in rock during loading sequences is considered. For this purpose, Acoustic Emission (AE) technique is used to monitor fracturing process of three rock types (onyx marble, sandstone and soft limestone) with different brittleness and sandstone samples under different loading rate. The results of experimental tests revealed that brittleness and loading rate have
Steel Supply Chain using Direct Reduction Method (DRI) includes all activities from supplying iron ore, concentrate, pellet, sponge iron and finally delivering the ultimate commodities to the steel production units. Different complexities and uncertainties of supply chains; such as limitation of suppliers and customers, variety of technical & economical option etc, cause to have a proper management of the supply chain. In this study, a system dynamic approach was used to simulate a dual-echelon of steel supply chain (iron ore-concentrate & concentrate-pellet). Hence, not only this study defines the influence of qualitative and quantitative variables in supply chain management (SCM), but also the interaction between variables and their feedb
Flotation is one of the most widely used operations in mineral processing plants and assumes a significant share of the total milling costs. The purpose of this paper is to introduce a new set of capital and operating cost models for major flotation machines based on the application of single (SRA) and multiple regression analysis (MRA). Thirty-seven major flotation machines were analysed for this purpose. Depending on the machinery type, different technical variables such as diameter, required air flow rate, required floor space, cell volume, required air pressure, and power were considered as predictor variables, individually (in SRA) or simultaneously (in MRA). Principal component analysis (PCA) was used in MRA due to the high correlatio
Cut-off grade and capacity of processing plant are two factors influencing the design and the feasibility study of mine and calculation of these two plays an important role in mining economy. The main purpose of this study is to optimize the cut of grade and production capacity considering price uncertainty, simultaneously. Slight changes on lane algorithm and its formulation as a nonlinear programming problem were done, leading to design a model that can optimize the both factors simultaneously. A heuristic model similar to geometric Brownian model has been used to consider uncertainty in the model. An assumed copper mine data were used to model verification. Solver plugin in excel for model solving was used. Finally, the recommended value