Collaborative Mining Sequence Optimization for Multiple Stopes under Intensive Mining

The optimization of a mining sequence not only reduces stress concentration in surrounding rock but also prevents underground debris flows, significantly improving safety. Firstly, the 870–898 m level of the eastern mining area in the Tiaoshuihe phosphate mine was divided into 25 ore blocks, and six different mining sequences were designed for this area. Then, it was calculated that five ore blocks must be processed simultaneously to reach the annual production output. The distances between the five simultaneously mined ore blocks will inevitably affect the efficiency of the equipment for any scheme. So, a collaborative model considering both the area stability and production capacity was established by combining the distance between the centers of the five ore blocks as an index. Differences in stability, deformation, and plastic zone size between the schemes are compared. The calculation results show that a mining scheme with a convex stepped shape produces the best results. These results provide a general method for entropy-based mining sequence optimization and an optimal solution for the Tiaoshuihe phosphate mine.

Research on Optimization of a Solid Filling Mining Face Layout Based on a Combined Clamped Beam Model

Optimizing the mining scheme is an essential work for improving recovery efficiency of filling mining. An optimization equation of mining face width under a gangue mining condition is derived firstly. Then, analysis of the optimization equation of the mining face width is carried out based on the measure data of the F5001 mining face in the Tangshan Coal Mine. At last, the reasonable mining face width is determined combined with numerical simulation. Results show that mining face width and roof subsidence increase with the increase of unit weight and mining depth, but decrease with the increase of the elastic modulus of roof. The maximum width of the mining face is 105 m in Tangshan Coal Mine. When the mining width increases from 66 to 105 m, the increasing percentage of roof subsidence is 15–18%. Roof subsidence is controlled less than 30% of the mining height. The variation range of the maximum roof subsidence is small, which means the mining face width can be designed reasonably through the proposed equation.

A differentially private distributed data mining scheme with high efficiency for edge computing

A wide range of data mining applications benefit from the low latency offered by edge computing. However, edge computing suffers from limited computing resources, which inhibits the applications of the computationally expensive data mining methods. In the edge-cloud environment, usually, the participants turn to collaboratively train machine-learning models that yield more accurate prediction results. However, data owners may not be willing to sharing the own data for the privacy concerns. To handle such disparate goals, we focus on tree-based distributed data mining scheme with differential privacy, which is computationally friendly. The basic idea of our approach is based on a distributed ensemble strategy. Each participant builds an elegant decision model based on their own data, which has a good tradeoff between the computation and the accuracy of the data distribution, and shares it with other participants after being injected with the elaborate noise. Then the useful knowledge transferred from the decision models is acquired by other participants in an adaptive ensemble strategy. Both the theoretical analysis and the experiments show that our scheme provides an efficient data mining manner that can achieve a good prediction accuracy while providing rigorous privacy guarantee over the distributed data.

Modernization of Mining Scheme in Developing Peat Deposit

The article presents the results of the study of a peat deposit development scheme with improved spread parameters. The parameters are improved by forming the spread as moulded particles of a certain shape and size determined by the size of moulding machine grooves and the degree of peat relaxation. To obtain such particles a milling cutter is proposed to be replaced by a moulding mill at the stage of peat deposit milling. When excavated, the peat mass is loosened and fed into a roller moulding machine where the rollers, rotating in opposite directions, capture it and the peat is compressed. The loose structure changes into dense particle-particle packing. The circumferential speeds of roller rotations are equal. A trapezoidal groove profile is chosen for the moulded particles to leave it. The groove depth is 10 mm. The uniformity of the moulded enlarged particle distribution over a drying field is characterized by a spread variation coefficient, which allows the spread quality to be evaluated. The enlarged particle spread is normalized by some cumulative actions characterizing the spread by parameters (the thickness, the average particle size, the size uniformity, the number of layers). Therefore, the drying of enlarged particles is intensified and peat yield per unit area is increased.

Using a Text Mining Approach to Hear Voices of Customers from Social Media toward the Fast-Food Restaurant Industry

Due to the COVID-19 pandemic, the sales of fast-food businesses have dropped sharply. Customer satisfaction has always been one of the key factors for the sustainable development of enterprises. However, in the fast-food restaurant business, gaining the knowledge of customer satisfaction is one of the critical tasks. Moreover, text reviews in social media have become one of important reference sources for customers’ decisions in buying services and products. Therefore, the main purpose of this study is to explore whether customer voices from social media reviews are different during the COVID-19 outbreak and to propose a new method to reduce interpersonal contact when collecting data. A text mining scheme which includes least absolute shrinkage and selection operator (LASSO) and decision trees (DT) are presented to discover the essential factors for customers to increase their satisfaction from unstructured online customer reviews. Finally, three real world review sets were employed to validate the effectiveness of the presented text mining scheme. Experimental results can help companies to properly adapt to similar epidemic situations in the future and facilitate their sustainable development.

Research on Suitable Mining Technology for Placer Titanium Mines in Vietnam

Vietnam has a potential reserve of placer titanium of around 650 Mt. The reserve lays in sandy beaches of the country from Thanh Hoa to Binh Thuan province. Placer titanium mines in Vietnam are different in geological condition, the scale of production, mining method, and environmental protection solutions, etc. Some of them are operating with inappropriate mining technology; therefore, have caused environmental issues and ineffective operation. Consequently, it is essential to have criteria for selecting appropriate mining technology to approach the sustainable development for the mines. Based on categories of geology, the scale of production, mining characteristics, requirements of safety, land reclamation and environmental protection, and mining effect, authors defined the criteria and method for selecting adequate mining technology for the placer titanium mines in Vietnam which aim for better safe, effective and sustainable. The categories to select the appropriate technology for coastal titanium placers in Vietnam including 1- feasible mining scheme, 2- mining procedure, 3- requirement volume of water, 4- slope stability, 5- environmental rehabilitation and reclamation, and 6- economic effect. The result of the application for Nam Suoi Nhum placer titanium mine in Bình Thuan province shows that the most appropriate scheme of this mine is the mining technology of using hydraulic jets, pumping and hauling by pumping mud, processing by spiral screws, and discharging by mud pumping.