Current Issue : July-September Volume : 2022 Issue Number : 3 Articles : 5 Articles
In the process of open-pit mining, the system parameters determine the economic benefit and production efficiency of the mine. Conventional optimization involves building a system model for the process parameters. However, complex large-scale systems such as open-pit mining are difficult to model, resulting in a failure to obtain effective solutions. -is paper describes a system simulation method for the process parameters involved in open-pit mining. -e nature and interaction of each component of the system are analyzed in detail, and the logical flow of each layer of the system is determined. Taking the basic operational linkages of the equipment as the system drivers, we obtained the operational flow of dragline information. -e barycentric circular projection method is used to simplify the control logic of the system, and a system storage state model is constructed to identify dynamic changes in the system and obtain the operation parameters of the dragline. A discrete event system is used for quantitative modeling, and the event step method is employed to advance the simulation process and obtain decision information. Finally, simulations are performed using various system parameters. -e simulation results show that the maximum efficiency is achieved when the dragline height is ∼13 m, giving a capacity of 4276.52m3/h. Error analysis indicates that the modeling error is minimized using a simulation correction coefficient of α � 0.94....
An investigation was conducted to study the viability of using waste paper pulp ash as an alternative material applied as a partial replacement of cement in the manufacturing of concrete and its effect on the properties of concrete, and also, the cost and environmental advantage of using waste paper were examined. Four concrete mixes with 0%, 5%, 10%, and 15% waste paper pulp ash replacement of OPC and PPC for 25MPa concrete were prepared. Based on the results obtained from the research, the highest compressive strength obtained at all test ages, i.e., 3, 7, and 28 days, were, 24.36, 28.35, and 36.83MPa, respectively, with 5% replacement of waste paper pulp ash for OPC, and for PPC, all percentage replacements showed reduction in compressive strength than the control mix. The water absorption of concrete was increased with increasing the percentage of waste paper pulp ash than control concrete. The control concrete clearly has the lowest resistance to 2% sulfuric acid solution compared to blended concrete of OPC-WPPA and PPC-WPPA. The cost comparison indicates that the incorporation of waste paper pulp ash decreases the cost of concrete and WPPA and saves raw materials used in cement and concrete production....
Gas disasters have been affecting coal mine safety production. With the gradual deepening of coal resources development, whether gas extraction meets the standard is particularly important. In view of the low extraction efficiency, through theoretical and numerical simulation combined with field measurement, the upper and lower cross bedding drilling is studied. Through the simulation and comparison of gas pressure at different extraction time and the gas pressure changes when the spacing of boreholes is 8 m, 10 m, and 12 m, the results show that, under the designed parameters, when the pressure value at the middle of the two boreholes starts to be less than 0.74 Mpa, the standard extraction time of the upper and lower cross strata boreholes is 160 days, and the most suitable spacing of boreholes is 10 m. Combined with the actual situation of Baode Mine, the extraction effect of cross drilling and parallel drilling was compared. The research shows that the predrainage effect of cross drilling is obviously better than that of parallel drilling. Cross drilling improves the predrainage effect, prolongs the action time of gas extraction by drilling, and effectively eliminates the risk of coal seam outburst....
After drilling a borehole in the ground and in a rocky environment, the materials around the borehole are crushed and separated in layers from the borehole wall; this causes the borehole cross section to lose its original circular shape, which redistributes stresses and further failure. )is type of episodic failure, which occurs symmetrically and V-shaped on both sides of the borehole and along the minor principal stress, is called breakout. )e dimensions of breakout, i.e., its depth and width, are two important indicators that have recently been used in estimating in situ stresses; however, the dimensions of the breakout area depend on the in situ stresses and mechanical properties of the rock, which have not been well addressed so far. )is paper presents a comprehensive investigation of breakout dimensions using finite element numerical analysis. )e proposed numerical model is based on the equations governing the two-dimensional breakout phenomenon under nonisotropic in situ stresses and plane strain condition. According to the results, increasing the failure function of the area around the breakout tip causes the breakout to expand, until the failure function is less than 1 for all points around the breakout tip, at which point the breakout expansion is stopped and breakout reaches stability. In the other part of the article, using 121 datasets obtained from numerical analysis, an artificial neural network is trained to predict breakout dimensions based on the input parameters of the problem. )emain finding of this section is a model that shows that among the parameters affecting the borehole breakout, the internal friction angle of the rock has the greatest impact on the dimensions of the breakout....
Recycling is among the best management strategies to avoid dispersion of several types of wastes in the environment. Research in recycling strategies is gaining increased importance in view of Circular Economy principles. The exploitation of waste, or byproducts, as alternative aggregate in concrete, results in a reduction in the exploitation of scarce natural resources. On the other hand, a productive use of waste leads to a reduction in the landfilling of waste material through the transformation of waste into a resource. In this frame of reference, the paper discusses how to use concrete as a container of waste focusing on the waste produced in limestone quarries and taking the challenge of introducing plastic waste into ordinary concrete mixes. To prove the possibility of reaching this objective with acceptable loss of performance, the mechanical characteristics of concrete mixed with additional alternative aggregates classified as waste are investigated and discussed in this paper through the presentation of two experimental campaigns. The first experimental investigation refers to concrete made with fine limestone waste used as a replacement for fine aggregate (sand), while the second experimental program refers to the inclusion of three types of plastic wastes in the concrete. Different mixes with different percentages of wastes are investigated to identify possible fields of application. The experimental results indicate that use of limestone quarry waste and use of plastic waste are possible within significant percentage ranges, having recognized a limited reduction of concrete strength that makes concrete itself appropriate for different practical applications....
Loading....