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The delineation of the open-pit mining boundary, particularly in the context of medium to long-term planning, forms the foundation of mining design. However, due to the non-linear and dynamic nature of the economic and technical parameters influencing boundary delineation, determining the optimal mining boundary can be exceedingly challenging. Currently, most boundary optimization methods assume that block parameters remain fixed, which results in enterprises assuming a certain level of risk when facing changes in internal and external conditions. In this regard, this paper introduces the concept of "achievement degree" to reflect the risk associated with the results of boundary design. Using coal prices as an example, this article applies the predicted coal price curve to boundary optimization adjustments by specifying the "achievement degree" requirements for various time periods, thereby facilitating risk-controlled and economically optimal boundary decisions. Taking the illustrative case of an idealized small-scale inclined coal seam open-pit mine, adjustments to the boundary closely track variations in coal prices, further enhancing returns. The results demonstrate that the method proposed in this paper can increase overall revenue by approximately 51.15% within the forecast period, while effectively managing risks. [ABSTRACT FROM AUTHOR]

To address the problem of excessive local secondary stripping between adjacent mining areas in open pit mines caused by internal row raising, a multivariate function was fitted to the model of the main mining seam of Zhundong open pit coal mine in Xinjiang, and the different locations of the end gang of the second mining area were divided into multiple sections at certain step sizes and calculated by integration, resulting in stripping ratios for each section, which were fitted to a stripping ratio curve. The optimal location of the mining area boundary was found to be 55 m westward offset from the mining area boundary in the inner row of the raised section, and numerical simulations based on the strength reduction method were applied to analyse the slope stability of the end gang at this location. The results of the study show that the analysed slope meets the stability requirements and the optimised new boundary avoids the stripping of approximately 65,837,376 m3 of economically unreasonable section. [ABSTRACT FROM AUTHOR]

Reasonable production capacity is related to the economic benefits of an open-pit coal mine. This study analyzes the relationship between the working face length, the annual advancing speed and the production capacity. It constructs a production capacity function relationship model. Take the Baorixile open-pit coal mine as an example. The remaining unmined parts are divided into four regions, and the range of production capacity in each region is analyzed by the established model and the determined respectively. On this basis, three mining district division plans are proposed. By analyzing and comparing the stripping ratio, mining life of the district, fault influence, difficulty of transition connection in the mining districts, the convenience of transportation system layout and other indexes of each plan, Plan 3 is determined to be the optimal plan. The production capacity planning results of each mining district in this plan are as follows: the production capacity of the 3rd mining district is 30–35 Mt/a; the production capacity of the 4th mining district in Region 1 is 20–31 Mt/a, and the production capacity in Region 2 is 24–33 Mt/a; the production capacity of the 5th mining district is 20–27 Mt/a. [ABSTRACT FROM AUTHOR]

As an important link in the complex system engineering project of open pit mining, the quality of the boundary determines the performance of the project to a large extent. However, changes in economic indicators may raise doubts about the optimality of mining boundaries. In this article, a coal price time series forecasting model that considers some amount of redundancy is proposed, which combines an improved sparrow search algorithm (ISSA) and a least squares support vector regression machine regression (LSSVR) algorithm. The optimal values of the penalty factor and kernel function parameter of the LSSVR model are selected by ISSA, which improves the prediction accuracy and generalization performance of the forecasting model. A multistep decision optimization method under fluctuating coal price conditions is proposed, and the model prediction results are applied to the boundary optimization design process. Using the widely applied block model as the basis, a set of optimal production nested pits is obtained, allowing the realm design results to fit the coal price fluctuation trend and further enhance enterprise efficiency. The applicability and effectiveness of this method were verified by taking an ideal two-dimensional model and an inclined coal seam open-pit coal mine in Xinjiang as an example. [ABSTRACT FROM AUTHOR]

At present, the research on goaf at home and abroad mainly focuses on four aspects: detection technology, stability evaluation technology, governance technology and quality control technology. The most important of the above four aspects is goaf detection technology. In order to ensure the accuracy and precision of exploration, many geophysical methods and high-density geological drilling are usually used for exploration. In case of complex terrain, this method will increase the workload rapidly, and can not achieve a good balance between exploration cost and exploration quality. Goaf exploration methods are still in the development stage, and each geophysical exploration method has its limitations. This study makes full use of the existing detection technology to detect the complex mined-out area of East Open-pit Mine, 9 inferred mined-out areas and 9 suspected mined-out areas were found by using 3D seismic exploration method, transient electromagnetic method is used to delineate 223 abnormal areas at different elevations within the exploration range. 58 drilling holes are arranged in the suspected mined-out area of East Open-pit Mine. Combined with geological software, 3D model map of mined-out area is drawn, and the causes of formation of mined-out area are classified and analyzed. Using 3D laser scanning technology to study the visualization of hidden mined-out areas, the hidden mined-out areas are divided into three types through visualization research, and its formation mechanism is analyzed. It can be applied to detection of open-pit mines which have small underground coal mines and many mined-out areas with complex geometric shapes and has great significance to the proposal of stability treatment scheme of mined-out area. The novelty of this study is prove the area, shape, roof thickness and height of the mined-out area by using joint detection method and the hidden mined-out area is visualized by 3D laser scanning technology. [ABSTRACT FROM AUTHOR]

In the initial production phase of an inclined seam opencast mine, due to initial investment and production capacity constraints, zoning or phasing is usually used, resulting in changes in the length of the working line during the transition of the mining area. To simplify the process, this article analyses the changes in the length of the working line during the period of slow gang steering in inclined seam opencast mines. In order to simplify the process, this article analyses the changes in the length of the working line in each period. The relationship between the length of the working line and the realm stripping ratio in the overlapping area of the two mining areas is discussed, and the variation in the realm stripping ratio and the economically reasonable stripping ratio under different working line lengths is illustrated. The advantages and disadvantages of the different optimization options are described. The optimization method was applied to the Zhundong opencast coal mine to calculate the working line lengths for the two stages. The optimized stripping ratio for the second-stage south gang location is equal to the economically reasonable stripping ratio of 3.50 m3/t, which reduces coal compression and improves economic efficiency, and is a guideline for the study of the working line lengths in each stage of the open-pit mine slow gang turning. [ABSTRACT FROM AUTHOR]

In view of the inclined occurrence of coal seam in Heishan open-pit coal mine, in the longitudinal exploitation process of the first mining area, the height of the slope at the west end is increasing, and the occurrence of weak interlayer in the slope is in production. The failure mechanism and stability of the end slope of the inclined composite coal seam, which is typical of the West end slope of Heishan open-pit mine, are studied by means of field investigation, theoretical analysis, limit equilibrium analysis, and numerical simulation. The factors affecting the stability of the western side slope and the potential landslide mode are analyzed. The residual thrust method and simplified Bishop method were used to study the stability of two potential landslide modes on the western slope, and the landslide mode, final slope angle, and slope morphology were determined. FLAC3D was used to simulate the western end of the slope, reveal its landslide mechanism, and clarify the evolution law of the slope rock mass displacement. The results show that the landslide mode at the west end of the first mining area is the combined sliding mode of "cutting and bedding." With the decrease of longitudinal mining depth, the final slope angle functions from 40° to 37°. The stress and strain are concentrated at the weak layer of the coal floor of the western side slope 13-2 and at the foot of the slope. Meanwhile, the failure also occurs inside the slope. The internal cracks connect through the weak layer of the coal floor and slide along the weak layer of the coal floor 13-2. The displacement evolution law of the slope monitoring point shows that the deformation of the slope is mainly horizontal displacement, the maximum displacement deformation is at the foot of the slope, and the degree of displacement deformation of the slope surface is obviously greater than that of the inside of the slope. [ABSTRACT FROM AUTHOR]

Freeze–thaw circulation under different moisture contents is the main influencing factor of the soil strength characteristics at a dumping site. The fine-grained sand materials of an internal dumping site in the Yuanbaoshan open-pit mine of China were selected as the research object; the changes of soil strength and deformation characteristics of 5 types of freeze–thaw (F–T) cycles were studied under 8 types of moisture contents. The stress–strain curve of soil sample shows strain hardening after different F–T cycles. The shear strength of the soil material decreases unevenly with increasing number of F–T cycles, and the greatest decrease in the shear strength occurs after the first F–T cycle. Under the condition of the same F–T cycles, the cohesion and internal friction angle (shear strength parameters) of the soil material decrease nonlinearly with increasing moisture content and decay in the form of a power function. For the same moisture content, the effect of F–T cycling on the internal friction angle of the soil is small, but the cohesion of the soil decreases as the number of F–T cycles increases, eventually stabilising. A quadratic polynomial equation can accurately describe the quantitative relationship between the cohesion and number of F–T cycles, at the same time, the unified regression equations of cohesion, moisture content and F–T cycle are established. The research results provide an important idea for the design of dumps and slope stability analysis, especially for the first year after dumping. [ABSTRACT FROM AUTHOR]

This paper addresses a special truck routing optimization problem in open-pit mines based on the minimization of time-varying transport energy consumption. A mixed-integer programming model is formulated to clearly describe the engineering problem, and a series of constraints are deduced to strengthen the model. To ensure that the model has time-varying characteristics, a method to estimate time-varying parameters is proposed by using pattern recognition and trend surface estimation. This time-varying resistance coefficient is mainly used to describe the process of road damage caused by frequent rolling of heavy trucks on the road surface. At the same time, in order to make the truck routing converge to the optimal energy consumption solution quickly, some definitions and properties are then provided based on stochastic theory, and a strategy to improve the computational efficiency of the model is proposed using these properties. Finally, an improved genetic algorithm is designed to solve the model. The results of experiments show that the proposed algorithm is effective and efficient. [ABSTRACT FROM AUTHOR]

Abstract: 3D geological model of open pit is an information platform in the construction of digital mine, which plays a significant role in the engineering design and production management of open pit. In the AutoCAD 2008 platform, take an open pit for example, it is required to construct a geological database, to construct fault wire-frame model according to the fault lines, to construct a terrain model according to the present situation map of stope and topographic contour map, to construct coal solid model according to the borehole data and interpolation points, and realize a visible display of 3D geological model for the open pit; to construct a block model according to the coal & rock solid model, and add the attribute and assign some value to it, and then apply it to the calculation of stripping and mining quantities of open pit. Compared with traditional calculation method, this method is simple in operation, which enhances its calculation speed and precision. [Copyright &y& Elsevier]

Influenced by seasonal rainfall, the total groundwater inflow at the bottom of open-pit mines exhibits seasonal fluctuations. However, effective methods are lacking for forecasting groundwater inflow because groundwater inflow mechanisms remain unclear, thus hindering targeted seasonal adjustments of drainage measures. Consequently, the drainage capacity may be underutilized and emergency response capabilities may be insufficient. Addressing the aforementioned issues, this study investigated the intrinsic relationship between rainfall and groundwater inflow using seasonal time series analysis and proposes a groundwater inflow prediction model, aiming to explore the inherent correlation between precipitation and runoff. Moreover, seasonal adjustment strategies for drainage measures were explored. The proposed model can enhance the economic viability of drainage projects while ensuring safety. It addresses the key challenge of adapting measures to seasonal variations and provides a conceptual framework for optimizing drainage measures in open-pit mining. [Display omitted] • Considerate the pre-existing soil moisture in surface runoff calculation. • Proposed a rainfall forecasting method based on decomposition-reconstruction. • Derived the formula for the total water inflow at the pit bottom in open-pit mine. • Innovatively propose the seasonal optimization strategy for drainage measures. [ABSTRACT FROM AUTHOR]