China has strongly advocated the green development concept for cycle economy and ecological economy, which completely brings the new opportunity and challenges for the mineral industry. Therefore, to transform and update the mineral resources industry chain into an eco-cycle industry chain is the development directions for the mining companies. This article proposes the four aspects of economic operation, R&D, industry chain environmental impact and eco-cycle innovation to establish the green evaluation index system via AHP and expert scoring method, and combine with Entropy-TOPSIS model, and we make a case study for listed mining companies in China’s autonomous region. The findings of result analysis are that the construction of eco-cycle industry chain of china autonomous region listed mineral resources companies lies in primary stage, to achieve the transformation of the industry chain is essential, and to establish the concept of green development and increase investment in green technology contributes to the transformation and upgrading of the industry chain.
Keywords: Eco-cycle industry chain, index system, entropy-TOPSIS, mineral resources
To investigate the performance of multi-layer aluminum honeycombs under compression, experiments have been carried out, where crush behaviours were compared between two combinations by using finite element program ANSYS/LS-DYNA, and the validation of the FE model was approved by comparing the simulation result with the data from the experiment. The results show that the forcedisplacement curves of a multi-layer aluminum honeycomb reflect a trend, in which the peak forces decrease gradually with the increase of layers and the plateau stage is getting shorter with the curves becoming increasingly smooth. This trend is viewed as being beneficial to the compressive process when the specimens are fully crushed. The energy absorption is basically linearly proportional to the number of layers. The staggered arrangement should be given priority due to its energy absorption property.
Keywords: Multi-layer, aluminum honeycomb, crush, numerical simulation
Sulige gasfield in Ordos basin develops typical tight sandstone reservoirs with low porosity, low permeability and low pressure, and it is difficult to predict effective reservoirs by post-stack seismic techniques, so the key point for its seismic prediction is to detect effective reservoirs by prestack technology. Based on accurate geological structure and petrol physical analysis, first, we applied seismic waveform cluster technology, constrained by good loggings, in order to classify seismic phases and qualitatively predict formation structures. Then we used cross plot of P-wave and S-wave impedance to predict sandstone formation with great thickness, and used cross plot of elastic parameters from pre-stack joint inversion to predict effective reservoirs (gas-bearing layers). This technology is applied to determine well location and effectively guide well trajectory in addition with 3D visualization technology. This approach has achieved to quantitatively predict gas reservoirs compared to qualitative prediction before.
Keywords: Tight sandstone; pre-stack; effective reservoir; S-wave impedance: Poison’s ratio
configuration in vertical well tubing is proposed. The buckling configuration for the rod string constrained in vertical wellbores is divided into four sections: the bottom and second suspended sections, the middle helical section and the top suspended section. The mathematical model not only includes the bending differential equations above the four sections, the boundary conditions at two ends, but also the continuity conditions at contact points whose positions are variable. The numerical simulation of the entire rod string buckling configuration is realized through transforming the mathematical model into non-linear algebraic equations solved by a genetic algorithm. The simulation results show that the boundary conditions at the two ends have little effect on the helical buckling configuration, but, however, the boundary condition, especially at the bottom, has a considerable effect on the configurations of the suspended sections. Compared to the previous results, the new model provides a more accurate description of rod string buckling and can simulate a more genuine buckling configuration of the rod string in the downhole.
Keywords: Sucker rod string, genetic algorithm, Runge- Kutta, boundary constraint, buckling configuration
Integrating the characteristics of two structures, the combined retaining structure of batter anchor piles and slidresistant piles are applicable to high slope engineering with large horizontal load. This paper employs the finite element software ANSYS and the strength reduction method to explore how the various characteristic parameters of the structure, ranging from the inclination angle of the anchor pile, pile diameter, anchorage depth, to pile spacing, affect slope stability and load bearing properties of the structure. The analytic results show that: the inclination angle of the anchor pile should fall between 20° and 45°, the pile should be driven no less than 8m into the stable rock formation within the theoretical broken angle, but the distance should not be excessively deep, and the pile spacing should be 2~3 times the pile diameter.
Keywords: Batter anchor piles, combined retraining, characteristic parameter, finite element method, load bearing properties
The electrical coal consumption in our country presents non-stationary characteristics of seasonal periodicity and circular trend while seasonal adjustment can decompose this sequence into trend cycle element, season element and irregular component with practical economic meaning. Before seasonal adjustment, we need to eliminate the impact of outlier, workday and leap year in the sequence in original electrical coal consumption and then we can conduct decomposition on the trend cycle sequence after seasonal adjustment applying H-P filtering method. After that, we can select appropriate model to conduct electrical coal demand forecasting based on different characteristics like long-term trend, periodic cycle, seasonal factor and irregular component after decomposition. Through the empirical test of electrical coal consumption in our country for 192 months, the results indicate that the precision has been improved significantly in long-term electrical coal demand forecasting by using the improved seasonal adjustment model and method.
Keywords: Electrical coal demand; time sequence; seasonal adjustment; H-P filter; forecasting
To date, coalbed methane (CBM) explorationhas only achieved a big breakthrough in Fukang-Dahuangshan regions, while CBM exploratory wells in the other regions of the southeast Junggar basin exhibit poor exploration effects. The analysis suggests that three unclear factors, including CBM accumulation process, geological controlling factors and distribution principle of favourable areas, cause the mismatch between CBM exploratory well deployment and practical geological regularity. In this study, the systematic research about three unclear factors has been carried out for the first time. The research shows that the well-developed extruding thrust faults are beneficial to CBM enrichment and preservation in the study area. Sandy roof not only can form tight-sandstone gas reservoir, but also serve as the cap rock for underlying coalbed gases. Liuhuanggou-Fukang regions in the southern Junggar basin and depression regions in the eastern Junggar basin are all hydrodynamic stagnation areas beneficial to CBM enrichment. Seven typical CBM enrichment models are summarized in this study, and they have different development degrees and various controlling mechanism of CBM enrichment. Finally, a suitable mathematical evaluation model for CBM exploration potential is established, and seven prospective targets (e.g. Fukan, Liuhuanggou and Qigu areas, etc.) are selected to be the preferred areas for CBM exploration, and both of them are ordered on the basis of their Ui values. The findings provide the geological basis for future CBM exploration and deployment.
Keywords: Coalbed methane; controlling factor; enrichment model; prospective targets; Junggar basin
A continuous tailings discharge model is proposed to solve the problems of high fluctuations in underflow concentration and relatively low, unstable actual discharge concentration in vertical tailing silos. A mathematical model for continuous tailing discharge was derived based on mass balance equation. A partial differential equation related to the height of the tailing silo in the compression area and tailing slurry concentration was also obtained. Results of the centrifuge and intermittent sedimentation tests show that the effective solid stress equation and solid flux equation correspond with each other. Thus, the relationship between the height of the compression region and the underflow concentration is exponential; subsequently, the exponential equation can be fitted.
Keywords: Consecutive underflow, solid flux density function, effective solid stress, dynamic sedimentation
For weak rock mass with notable rheological property, instability is mostly caused by flowing deformation. As the basis for the design of roadway supporting structure, the rheological parameters of surrounding rocks are of great importance. Unfortunately, the rheological parameters obtained from indoor tests often fail to reflect the geological defects in a large research area due to the impact from constraints of sampling representativeness, sampling disturbance and testing technical level. What is worse, field tests are time-consuming, unrepeatable and costly. To solve these problems, this paper conducts inversion of the rheological parameters of surrounding rocks based on the BP neural network. Taking a mine roadway as an example and considering the vault subsidence data in the entrance section, the author applies FLAC3D in numerical simulation, adopts BP neural network for network learning and sample training, and performs displacement inversion of the rheological parameters of the surrounding rocks in the section.
Keywords: Numerical simulation; creep; BP neural network
To monitor the operation of coal mine safety production, an online learning method of fault identification for coal mine safety production through video probabilistic appearance manifolds is proposed in this paper. For a category of the coal mine equipment safety state, a common representation of the normal appearances of this category would usually be learned off-line. From video monitoring of this category, an appearance model can be learned online through a prior generic model and successive video. The further details, as well as both the normal and abnormal appearances, can be expressed as an appearance manifold. In our algorithm, an appearance manifold would be approximately estimated by a series of sub-manifolds, and each sub-manifold is further refined into a low-dimensional linear sub-space. Thus, the time required for image recognition is reduced to meet the demands of real-time image processing. Through experimental analysis, we can demonstrate that our online learning algorithm method is an efficient method for videobased image recognition, and its application in coal mine safety production has proven to be very effective.
Keywords: Probabilistic appearance manifolds, online learning, image recognition, coal mine