Stope Structure Parameters Research Articles

Enhancing stability graphs for stope design in deep metal mines using machine learning

Stope structural parameters, which are human-controllable, directly impact the safety and economics performance of underground mineral extraction. Current stope design still relies heavily on empirical methods such as stability graphs, due to the complex nature of rock masses and varied stope failure mechanisms. This study aims to enhance stability graphs with machine learning techniques. Firstly, a dataset of 980 records from unsupported stopes was compiled, representing perhaps the largest dataset of its kind so far in the literature. This was achieved through extensive literature review and the collation of an additional 289 records from Chinese mines which were previously not included. An analysis of data reveals that over 90 % of the records fall within a stability coefficient of 0–100 and a hydraulic radius of 0–20 m. Secondly, a stability graphs optimization process was established using Python, eliminating the subjectivity of partitioning. Nine supervised machine learning algorithms were employed and trained to test their performance in partitioning form and predicting accuracy. It was found that the neural network algorithm demonstrated the best overall performance. At last, a neural network with the Keras framework was used to establish a new multilayer perceptron model to generate safety factor probability curves, which were then used to construct the stability graph. To facilitate practical use, mathematical functions fitting safety factor curves within the unstable zone were further formulated. Compared with other empirical stability graphs, our new approach allows designers to more efficiently and reliably select safety factors to determine the stability state according to site specific conditions and technical support systems, thereby providing enhanced guidance for stope design.

Optimization of stope structure parameters by combining Mathews stability chart method with numerical analysis in Halazi iron mine

When employing the open stope mining method for extracting materials in underground mines, it is necessary for personnel and equipment to operate within a specified range of the goaf area, thus, adoption of appropriate mining parameters in the mining field is crucial for promoting safe production practices. In this study, the Harazi iron mine is taken as the research subject, with theoretical analysis combined with numerical simulation that enables the authors to simulate and analyze the width parameter of the mining field. Theoretical analysis utilizing the Matthew stability chart method confirms that the width of the mining field in Harazi iron mine should not exceed 9 m. Based on this finding, the mechanical response characteristics accompanying the mining process at different widths within the mining field limits are analyzed via the Flac3D numerical analysis software. As a result of this analysis, the optimal width of the mining field in Harazi iron mine is determined to be 8 m. The method utilized in this article provides a rational approach to determining structural parameters of the mining field and can effectively aid in promoting mine safety practices.

Stope Structural Parameters Design towards Green and Deep Mining: A Review

A reliable design of stopes is critical to ensure both safety and efficiency in mining operations. The evolving mining methods and technologies as well as increasing mining depth dictate the need to continually improve stope designs. This paper presents a comprehensive review in order to compare and consolidate various stope design methods. This review covers various aspects of stope design, including design principles, factors to consider, and the diverse range of design methods available. The results led to the classification of various methods encompassing engineering analogies, fundamentals, numerical simulations, and industrial tests. Of particular significance, the review furnishes detailed insights into the research conducted on each method, as well as each method’s practical performance in engineering applications. Furthermore, the review highlights the inherent limitations in current design methods and suggests potential avenues for future research. Finally, by comprehensively considering the functional roles and advantages of each design method, it overcomes the limitations of relying solely on a single method for stope structural parameter design, and a general process is proposed.

Design Method and Application of Stope Structure Parameters in Deep Metal Mines Based on an Improved Stability Graph

Deep mining has become an inevitable trend of mining development. Previously conducted studies have established that reasonable stope structure parameters are the premise to ensure the safe and efficient production of deep mines. In order to ensure the safety of deep mining, in this paper, we systematically review the existing stope structure parameter design methods, and then put forward a deep stope structure design method based on the stability of mining rock mass. Based on rock mass quality classification, this method uses a critical span graph and an improved stability graph, and fully considers the influence of joint occurrence and mining stress on the stability of surrounding rock, to design the stope structural parameters. Taking into consideration the deterioration of the quality of deep rock mass, we collect mining data at home and abroad, improve the stability graph, and make it suitable for the design of stope structural parameters with different mining methods. The design process of stope structural parameters is expounded through field engineering cases, and it has specific guiding significance for the design of stope structural parameters in deep metal mines.

Study on Stope Stability in Continuous Mining of Long-Dip, Thin Orebody by Room–Pillar Method

In order to analyze the stability of the stope under continuous mining with the room–pillar method for a kind of orebody with a long inclination, but not deep mining, this paper takes the room–pillar method for the continuous mining of a long-inclination orebody in the Mengnuo Lead–Zinc Mine, Yunnan Province as the research background. On the basis of the analysis of the stope mechanical model of a long, inclined, thin orebody with room-and-pillar mining, based on numerical simulation, the nature of the change in stress, displacement and the plasticity zone of the roof and pillar during continuous mining along the inclination are systematically analyzed. The results show that as the mining depth increases, the roof subsidence of the stope in the middle of the current operation increases. With the continuous mining of the lower middle section, the roof displacement of the stope will continue to increase with the subsequent mining of the middle section until the end of all stope operations, and the roof displacement of the stope has an obvious cumulative effect. The stress on the roofs and pillars increases with the gradual downward movement of the mining in each level, and the distribution of the plastic zone also expands. It shows that the stope structural parameters that are set according to shallow mining cannot fully meet the requirements of stability and safety in mining a deeper orebody. Therefore, for the mining of a non-deep orebody with a greater tendency to extend, the structural parameters of a shallow stope should not simply be used in the mining of a deeper orebody, but the pillar size should be appropriately increased or the spacing between the room and pillar should be reduced to ensure the stability and safety of the continuous stope.

Stability Evaluation and Structural Parameters Optimization of Stope Based on Area Bearing Theory

A reasonable and stable stope structure is the premise of realizing safe mining of underground metal ore. To safely mine the gently inclined medium-thick ore body, stope stability in Bainiuchang Mine was analyzed based on the pillar area bearing theory, and stope stability with regard to nine groups of structural parameters was numerically simulated. The results show that the existing stope structural parameters failed to maintain stability requirements and tended to be exposed to the risk of stope collapse. The middle section of the pillar as well as stope roofs and floors are vulnerable due to tensile stress when mining by open stoping, and the compressive stress concentration is prone to occur at the junction of the pillars, stope side walls, roofs and floors. Shear stress contributes little to pillar failure. The reasonable stope structural parameters of open stoping for the gently inclined medium-thick ore body in Bainiuchang mine are optimized using ANSYS numerical simulation: stope height 4.5 m, pillar diameter 4 m, pillar spacing 7 m and pillar row spacing 8 m. The onsite trial shows that the ore recovery rate reaches 82% under these parameters, which also realizes the equilibrium of safety and economy.

Study on Optimization of Stope Structural Parameters and Filling Scheme of Wawu Phosphate Mine in Yichang City, China

Reasonable stope structural parameters are very important to ensure the safety and efficiency of mining. In this paper, based on the elastic-plastic constitutive model of Mohr-Coulomb strength criterion, the reasonable span and critical span are calculated by using simply supported beam theory and mine room width calculation formula. PLAXIS2D finite element analysis software was used to conduct numerical simulation research on 7 m × 9 m, 5 m × 12 m stope structure parameter schemes and 7 m × 9m, 5 m × 12 m waste rock filling schemes. The optimal structure parameters of the stope were determined based on the calculation and analysis of displacement variation rule, surrounding rock stress distribution and plastic zone. The analysis and simulation results show that Case 1 one-time mining 7 m × 9 m and Case 3 one-time mining 5 m × 12 m, the plastic zone is connected, the simulation calculation is not convergent, and the stope is unstable. Case 2 waste rock filling 7 m × 9 m and Case 4 waste rock filling 5 m × 12 m, the distribution and change of stress, displacement and plastic zone in the goaf under the two cases are compared, and finally the waste rock filling 7 m × 9 m is obtained can improve the economy and safety of mining in the mining area, and verify the feasibility of implementing stope structural parameters and waste rock filling mining system is verified.

Study on Optimization of Stope Structure Parameters for Steeply Inclined Medium-thick Broken Ore Bodies

Study on Optimization of Stope Structure Parameters for Steeply Inclined Medium-thick Broken Ore Bodies

Study on the relationship between slurry film thickness and rheology of fillers based on film theory

The key problem of paste filling technology lies in whether paste can meet the requirements of stope structural parameters on cementing strength, pipe transportation and mining methods on filling performance. The separated paste will cause serious wear and even pipe blockage in the pipeline transportation process. If the paste is separated in the stope, the strength of the filling body will be uneven, and accidents such as delamination and stacking will occur. The occurrence of these situations is extremely unfavorable to the filling operation. Just as the material determines the performance, in order to ensure the paste has excellent filling performance, it is necessary to systematically study the internal relationship between paste filling materials and filling performance. Paste is a complex suspension system composed of aggregate, water, cementing materials and additives. Compared with traditional low-concentration classified tailings slurry, it has the characteristics of wide particle size distribution, high solid content, strong chemical action on particle surface, etc. Under the interaction of these factors, paste presents macroscopic characteristics such as plasticity and stability. These macroscopic characteristics are embodied in rheology, that is, rheological characteristics of paste. The research shows that the rheological properties of paste are affected by the gradation, concentration and cementing material of filling material, and the change of gradation of filling material has the most significant effect on the rheological properties of paste. The change of the micro-level composition causes the change of the rheological properties of the paste on the macro level, thus causing the change of the paste filling performance. In the final analysis, the gradation of the traceable filling material is an important factor that determines the paste filling performance.

Optimization of Stope Structure Parameters Based on the Mined Orebody at the Meishan Iron Mine

Based on the engineering background of the Meishan iron mine with sublevel caving (SLC) method, in this work, we adopted the method for identifying the shape of mined orebody (the original location in blasted slice), which analyzed and determined reasonable stope structure parameters. In the field test, the markers were arranged in the blasted slice, the mined orebody was measured by in situ tests, and reliable data were achieved. The shape of the mined orebody was obtained through this test when the width of drift was 6 m. The mined orebody’s shape was compared with the shape of the isolated extraction zone (IEZ), and the difference increased with increasing height. When the stope structural parameters were determined by the mined orebody, the larger the sublevel height was, the smaller the error was, which was compared with the method using ellipsoid arrangement theory to determine the stope structural parameters. Finally, the reasonable stope structure parameters were optimized. The sublevel height was 22 m, and the drift spacing was 20 m.

Optimization of Structural Parameters of Stope without Sill Pillar in Metal Mine by Computer Numerical Simulation

The determination and optimization of stope structure parameters is of great value in reducing the ore loss and dilution in the mining process, improving the production capacity of the stope, increasing the workload of mining and mining, reducing the investment cost of the mine and improving the mining efficiency. Based on this, this paper first analyses the parameter changes of stope structure parameters without sill pillars in metal mines, and then studies the optimization of structural parameters of stopes without sill pillars in metal mines based on orthogonal test method.

Sensitivity analysis of factors influencing pillar stability in the deep stope of underground salt mine

The orebody and the surrounding rock of underground salt mine are generally divided into soft rock or extremely soft rock. In these mines, the strip room pillar method is primarily used. Continuous pillars with a certain width are left between every two mining strips. These pillars are used to provide support to the overlying surrounding rock. However, the stability of the pillars restricts the stope structural parameters of the mining method. Thus, it is important to first determine the main factors that affect pillar stability and analyze the influence level of these factors. Using a deep mining underground salt mine as an example, the characteristics of pillar instability and the pillar load are analyzed. The safety factor of the pillar refers to the ratio of pillar strength to pillar load, which can be used to quantitatively evaluate pillar stability. Based on the formula of pillar stress and the empirical formula of pillar strength, the formula of the pillar safety factor is deduced. Based on this formula, the primary factors affecting pillar stability are comprehensively analyzed. Moreover, the sensitivities of these factors are compared and analyzed based on the orthogonal range theory. According to the calculation results of the range, the factors influencing pillar stability in the underground salt mine are the mining depth and uniaxial compressive strength of ore, which are the most significant factors, followed by the height and width of pillars, and then the room width and unit weight of the overlying strata, which have relatively small influence. The safety factor of the pillar is positively correlated with the pillar width and uniaxial compressive strength but negatively correlated with the mining depth, pillar height, room width, and the unit weight of the overlying strata. The specific reasons of each factor affecting the safety coefficient are analyzed in detail. The changing trend of the pillar safety factor with various influencing factors can provide an important basis for the optimal design of stope structural parameters and the determination of support scheme.

Optimum Sublevel Height and Drift Spacing in Sublevel Cave Mining Based on Random Medium Theory

Weak rock mass and poor flow of material can cause excessive ore loss and dilution in sublevel caving. This paper proposes a method to establish design parameters for an inclined deposit within a weak rock mass and evaluates its effectiveness through a case study. In order to solve the problem of low production capacity and poor safety conditions of sublevel caving mining at the Yingfangzi silver mine in China and to ensure a smooth production from the refractory ore body, it is necessary to select appropriate stope structure parameters. Based on random medium theory of gravity flow and the improved equation of ore discharge in random medium, an end wall drawing experiment is carried out to determine the optimum design and flow parameters. It was observed from the experiment that, due to the influence of the randomness of particle movement, there is a mismatch in the flow parameter measurement. The flow characteristics and distribution of the marker particles are different from that of the tested particles resulting in large drawbody shape distortion. The study finds that the flow parameters obtained by the new method are more practical and account for drawpoint width and recommends that the new method for determining the sublevel stope height is used when the drawbody is a non-standard ellipsoid. The outcomes have shown a significant reduction in the dilution and improvement in the recovery rates, and the safety and efficiency of mining have been greatly improved.

Optimization calculation of stope structure parameters based on Mathews stabilization graph method

Mathews stability graphic method, based on the rock classification system, measures the stability of the ore roof area of a relatively simple calculation method and provides a theoretical basis for mine rational design stope structure size parameters. In this study, we used a large-scale tungsten mine in Jiangxi Province as the engineering background and performed on-site engineering geological surveys and indoor ore rock mechanics tests in the middle section of mine 417 to obtain multiple engineering quality indicators for the mines and surrounding rocks. The Mathews stability map method and Barton limit span theory were used. The reasonable size range of the exposed face of the stope was calculated by performing theoretical analysis on the ultimate span. Then, FLAC3D calculation and analysis software were used for the simulation of the stope structure, and the most reasonable design of the exposed surface dimension was selected and used as reference for ensuring the safe production of the mine.

Multiple Attribute Decision Making of Stope Parameters Based on SPA-GRA Model

Aiming at the problems of multi-attribute and uncertainty in the selection of stope structural parameter scheme, we proposed a new multi-attribute decision-making model of stope parameters based on set pair analysis and grey relational theory. Based on the SPA-GRA theory, we used the dialectical viewpoint of opposition and unity to combine the determinacy and uncertainty factors, and establish the set pairs between evaluation set and index set respectively. In addition, we quantitatively analyzed the correlation degree of the set pair’s identity, diversity and opposites. Through comprehensively evaluating 6 characteristics of 5 stope schemes, we determined the grade of stope structural parameters and chose the best scheme. The research shows that the evaluation method is used to fully consider the identity, diversity and opposites of the comparison set, which avoids the inevitable one-sidedness in the past evaluation process. It is more objective, comprehensive and reasonable and it can be applied and popularized in the engineering field.

Numerical Optimization of Broken and Difficult for Stope Mining in Underground Metal Mines

In a metal mine, there is a great risk of mining hidden resources caused by unreasonable mining in the early stage. In order to effectively and safely mine this part of the resources, it is based on investigating the current status of mining and delineating the area of instability and collapse, the area is firstly grouted and strengthened and temporarily supported, and then the first mining site and its mining method in the hidden danger area are given. The 3D model of the original goaf was constructed, and the numerical analysis model was introduced and numerical simulation was carried out, the results show that: 1) grouting reinforcement treatment and temporary support measures can effectively control the surrounding rock to continue collapse; 2) the original three-dimensional visualization model of the original goaf can reflect the real situation of the first mining stope; 3) based on the results of comprehensive numerical analysis, the stope structure parameters of the first stope are obtained, the length, width and height are 31×7.5×28.8m and 36×7.5×28.8m, respectively. The optimized result realizes the safe mining of the stope and provides reference and reference for the mining of similar stope.

Digital Precision Design For a Platinum Gold Mine With Deep Ming in South Africa

A platinum mine in South Africa is a deep mining mine that the mining design involves a series of difficult problems, such as high stress, high temperature and high lifting and so on. Choosing the right mining method and developing system is the key technology to solve these problems, and is also an important plan for mining design. First of all, based on multi index factors, 6 mining methods were quantitatively analyzed and scored, and the subleve open stoping method was chosen as the best mining method. In order to ensure the safety of this mining method, the hydraulic radius theory is introduced to analyze stope structural parameters stability. Secondly, with the view of global mining technology, we compared the development system of South Africa, China, Australia and other countries, and compared 6 development options in terms of technical, economic and security factors. The final selection of the development system combines the Chinese and Western design concepts, absorbs the advantages of each other and gets the recognition of the owners. Finally, we optimized the mining block, and carry out the 3D dynamic programming for the development system based on the 5Dplaner software, which realizes the digital precise design for the mine.

Rock Mechanics Characteristics Test and Optimization of High-Efficiency Mining in Dajishan Tungsten Mine

Rock mechanics test is not only the basis for obtaining the mechanical parameters of rock but also an important means for studying rock mechanics and engineering. In this paper, the uniaxial compression deformation test, Brazilian splitting test, and cornea pressure shear test are carried out for rocks in the Dajishan tungsten mine. The basic mechanical parameters such as uniaxial compressive strength, tensile strength, elastic modulus, Poisson’s ratio, and internal friction angle of ore rock and surrounding rock are obtained. Meanwhile, damage characteristics of rock are deeply studied and analyzed under different experimental conditions. According to rock mechanics parameters which are obtained from indoor rock mechanics tests, three design schemes of stope structure parameters are optimized by using the FLAC3D numerical simulation software. On the premise of ensuring the stability of the stope structure, the recovery rate of ore and the production capacity of the stope are taken into consideration. It is suggested that the second scheme should be adopted for mines (18 m for ore room and 7 m for ore pillar), which provides scientific guidance for the safe and efficient mining of mines.

Optimization of Stope Structural Parameters Based on Mathews Stability Graph Probability Model

Strip mining with subsequent filling is one of the main mining methods for gently inclined thin ore bodies. The production process of excavating alternate strips is beneficial to the safety of mining. Reasonable stope structural parameters are key to achieving safe and efficient mining. The Tiaoshuihe phosphate mine of Sanning Mining is taken as an example in this study. Based on precision finite element modeling and simulation, a reasonable width range and the interval value of the strip are determined. A reliable and efficient strip width is calculated by using the probability model of the improved Mathews stability graph method. The results show the following. Firstly, under the geological conditions and backfill environment of the Tiaoshuihe phosphate mine, the reasonable and safe strip width interval is 7–9 m. Secondly, the probabilities of open stope stability with strip widths of 7, 8, and 9 m are 88.55%, 86.76%, and 84.94%, respectively. The reasonable probabilities of stope stability with strip widths of 7 and 8 m are higher than 85%. Thirdly, combining this with the drilling equipment operation parameters, it is suggested that the best strip width is 7 m without increasing the strength of the backfill.

Optimization Research of Stope Structural Parameters in Upward Drift Cut-and-Backfilling Mining Method

Focus on a-400m level stoping in a gold mine, the ANSYS numerical software was used to study the stope structural parameters in upward drift cut-and backfilling mining methods. First, according to engineering experience, the design of stope structural parameters was obtained. Then the stoping process of both the first drift and the second drift was simulated by the numerical software. The vertical maximum displacement and the vertical maximum stress were selected as evaluation indexes for analysis. The result shows that the third project, whose drift width is 4 m and layer height is 3 m, have the best effect with the less displacement and stress compared with other projects.