scholarly journals Dynamic capacity balance between stripping and mining of a dragline stripping system

2020 ◽  
Vol 7 (2) ◽  
pp. 380-387
Author(s):  
Shuangshuang Xiao ◽  
Guowei Dong ◽  
Hongsheng Wang
Keyword(s):  
Coal Seam ◽  
System Reliability ◽  
Production Capacity ◽  
Weighted Average ◽  
Generalized Regression Neural Network ◽  
Coal Production ◽  
Average Thickness ◽  
Measurement Methodology ◽  
The Stability ◽  
Coal Seam Thickness

AbstractThe reliability factors of a dragline stripping system were analyzed using system reliability theory to improve its reliability and ensure the stability of surface coal mine production. The relationship between the dragline scheduled stripping volume with both the weighted average thickness of the coal seam and the height of the blast casting bench was derived. The results show that the reliability of the dragline stripping system decreases with the weighted average thickness of the coal seam and increases with a reduced casting blast bench height and monthly raw coal production capacity. Furthermore, the dynamic monthly advance distance of the dragline stripping system was found, a new concept of the dragline stripping system reliability and measurement methodology were proposed, and a prediction model for the dragline production capacity was established using a generalized regression neural network. In addition, the steps and processes of the reliability were improved. The study on the Heidaigou surface mine shows that the height of the casting blast bench should be reduced to 10.5 m when its raw coal production capacity is improved from 20 to 30 Mt/a. During the normal production of surface coal, the system reliability can be improved by dynamically determining the weighted average coal seam thickness, accurately predicting the dragline production capacity, and taking other corresponding measures.

scholarly journals Study on the Stability of the Coal Seam Floor above a Confined Aquifer Using the Structural System Reliability Method

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Haifeng Lu ◽  
Xiuyu Liang ◽  
Nan Shan ◽  
You-Kuan Zhang
Keyword(s):  
Coal Seam ◽  
System Reliability ◽  
Failure Modes ◽  
Water Inrush ◽  
Series System ◽  
Mechanical Parameters ◽  
Structural System ◽  
Key Strata ◽  
Structural System Reliability ◽  
The Stability

A quantitative method of structural system reliability was proposed to study the influence of random rock mechanical parameters and loads on the stability of the coal seam floor above confined aquifers. To obtain the reliability probability of the floor, two modes of water-resistant floor failure were suggested as follows: (1) mining completely removed the water-resistant key strata of the floor. In this case, the failure modes were of three main types: mining failure, confined water intrusion, and combined mining failure and intrusion. (2) Failure modes included shear and tensile failures when the thickness of the key strata was greater than 0. On the basis of the elastic thin plate theory, the performance function that calculates the reliability probability of all modes could be obtained. The failure modes were regarded as the series system. The Monte Carlo method was employed to calculate the reliability probability of each failure mode and series system. The results showed that the random rock mechanical parameters and loads of the key strata significantly influence the antiwater inrush capacity of the floor. In addition, the water inrush coefficient and reliability probability can be simultaneously used as the evaluation indexes of water inrush risk. Both these indexes could improve the assessment of the reliability of the floor.

INTEGRATED APPROACH FOR SELECTING THE EFFECTIVE SCHEME FOR PREPARING THE MINING FIELD

2020 ◽  
Vol 3 (1) ◽  
pp. 100-112
Author(s):  
A.A. BELODEDOV ◽  
◽  
D.N. SHURYGIN ◽  
Keyword(s):  
Mathematical Model ◽  
Coal Seam ◽  
Production Capacity ◽  
Economic Assessment ◽  
Integrated Approach ◽  
Coal Production ◽  
Capital Investments ◽  
Mine Field ◽  
Current State

The analysis is carried out and the problems of the current state of mining in the coal mines of the Russian Donbass are identified. To increase the efficiency of their work, it is proposed to create a mathematical model that allows tracing the probable zones of tectonic disturbance. We apply this technique for the southeastern wing of the inclined part of the mine field of the Sadkinskaya mine. On the basis of the constructed forecast map of coal seam disturbance, we solve the problem of choosing the optimal cutting of a section of a mine field. To do this, we make a technical and economic assessment taking into account such factors as: losses and quality of mined coal, production capacity of the mine and time for preparation and development, volume of capital investments, cost, taking into account costs when crossing disturbed zones.

scholarly journals On the optimal control of coronavirus (2019-nCov) mathematical model; a numerical approach

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
N. H. Sweilam ◽  
S. M. Al-Mekhlafi ◽  
A. O. Albalawi ◽  
D. Baleanu
Keyword(s):  
Mathematical Model ◽  
Optimal Control ◽  
Weighted Average ◽  
Necessary Optimality Conditions ◽  
Numerical Approach ◽  
Population Number ◽  
Infected People ◽  
The Stability ◽  
Novel Coronavirus ◽  
Theoretical Results

Abstract In this paper, a novel coronavirus (2019-nCov) mathematical model with modified parameters is presented. This model consists of six nonlinear fractional order differential equations. Optimal control of the suggested model is the main objective of this work. Two control variables are presented in this model to minimize the population number of infected and asymptotically infected people. Necessary optimality conditions are derived. The Grünwald–Letnikov nonstandard weighted average finite difference method is constructed for simulating the proposed optimal control system. The stability of the proposed method is proved. In order to validate the theoretical results, numerical simulations and comparative studies are given.

scholarly journals Antarctic sea-ice thickness and volume estimates from ice charts between 1995 and 1998

2015 ◽  
Vol 56 (69) ◽  
pp. 383-393 ◽  
Author(s):  
E. Rachel Bernstein ◽  
Cathleen A. Geiger ◽  
Tracy L. Deliberty ◽  
Mary D. Lemcke-Stampone
Keyword(s):  
Sea Ice ◽  
Regional Scale ◽  
Weighted Average ◽  
Ice Thickness ◽  
Average Thickness ◽  
Sea Ice Thickness ◽  
Subjective Analysis ◽  
Stage Of Development ◽  
Volume Estimates ◽  
The Impact

AbstractThis work evaluates two distinct calculations of central tendency for sea-ice thickness and quantifies the impact such calculations have on ice volume for the Southern Ocean. The first calculation, area-weighted average thickness, is computed from polygonal ice features and then upscaled to regions. The second calculation, integrated thickness, is a measure of the central value of thickness categories tracked across different scales and subsequently summed to chosen regions. Both methods yield the same result from one scale to the next, but subsequent scales develop diverging solutions when distributions are strongly non-Gaussian. Data for this evaluation are sea-ice stage-of-development records from US National Ice Center ice charts from 1995 to 1998, as proxy records of ice thickness. Results show regionally integrated thickness exceeds area-weighted average thickness by as much as 60% in summer with as few as five bins in thickness distribution. Year-round, the difference between the two calculations yields volume differences consistently >10%. The largest discrepancies arise due to bimodal distributions which are common in ice charts based on current subjective-analysis protocols. We recommend that integrated distribution be used for regional-scale sea-ice thickness and volume estimates from ice charts and encourage similar testing of other large-scale thickness data archives.

scholarly journals Evaluating irrigated rice yields in Japan within the Climate Zonation Scheme of the Global Yield Gap Atlas

2021 ◽  
pp. 1-12
Author(s):  
S. Ishikawa ◽  
T. Nakashima ◽  
T. Iizumi ◽  
M. C. Hare
Keyword(s):  
Production Capacity ◽  
Aridity Index ◽  
Data Sets ◽  
Yield Gap ◽  
Yield Data ◽  
Irrigated Rice ◽  
Rice Yields ◽  
The Stability ◽  
Temperature Seasonality ◽  
Government Statistics

Abstract The Global Yield Gap Atlas (GYGA) is an international project that addresses global food production capacity in the form of yield gaps (Yg). The GYGA project is unique in employing its original Climate Zonation Scheme (CZS) composed of three indexed factors, i.e. Growing Degree Days (GDD) related to temperature, Aridity Index (AI) related to available water and Temperature Seasonality (TS) related to annual temperature range, creating 300 Climate Zones (CZs) theoretically across the globe. In the present study, the GYGA CZs were identified for Japan on a municipality basis and analysis of variance (ANOVA) was performed on irrigated rice yield data sets, equating to actual yields (Ya) in the GYGA context, from long-term government statistics. The ANOVA was conducted for the data sets over two decades between 1994 and 2016 by assigning the GDD score of 6 levels and the TS score of 2 levels as fixed factors. Significant interactions with respect to Ya were observed between GDD score and TS score for 13 years out of 21 years implying the existence of favourable combinations of the GDD score and the TS score for rice cultivation. The implication was also supported by the observation with Yg. The lower values of coefficient of variance obtained from the CZs characterized by medium GDD scores indicated the stability over time of rice yields in these areas. These findings suggest a possibility that the GYGA-CZS can be recognized as a tool suitable to identify favourable CZs for growing crops.

SUBSTANTIATION FOR SIMPLIFICATION OF CALCULATION MODELS FOR ASSESSMENT OF THE STABILITY OF ROOF ROCKS

2021 ◽  
pp. 25-36
Author(s):  
Oleksandr Ahafonov ◽  
◽  
Daria Chepiga ◽  
Anton Polozhiy ◽  
Iryna Bessarab ◽  
...  
Keyword(s):  
Differential Equations ◽  
Coal Seam ◽  
Cross Section ◽  
Three Dimensional ◽  
Theory Of Elasticity ◽  
Unit Width ◽  
Distributed Load ◽  
The Stability ◽  
Roof Rocks ◽  
Calculation Models

Purpose. Substantiation of expediency and admissibility of use of the simplified calculation models of a coal seam roof for an estimation of its stability under the action of external loadings. Methods. To achieve this purpose, the studies have been performed using the basic principles of the theory of elasticity and bending of plates, in which the coal seam roof is represented as a model of a rectangular plate or a beam with a symmetrical cross-section with different support conditions. Results. To substantiate and select methods for studying the bending deformations of the roof in the coal massif containing the maingates, the three-dimensional base plate model and the beam model are compared, taking into account the kinematic boundary conditions and the influence of external distributed load. Using the theory of plate bending, the equations for determining the deflections of the coal seam roof in three-dimensional basic models under certain assumptions have a large dimension. After the conditional division of the plate into beams of unit width and symmetrical section, when describing the normal deflections of the middle surface of the studied models, the transition from the partial derivative equation to the usual differential equations is carried out. In this case, the studies of bending deformations of roof rocks are reduced to solving a flat problem in the cross-section of the beam. A comparison of solutions obtained by the methods of the three-dimensional theory of elasticity and strength of materials was performed. For a beam with a symmetrical section, the deflection lies in a plane whose angle of inclination coincides with the direction of the applied load. The calculations did not take into account the difference between the intensity of the surface load applied to the beam. Differences in determining the magnitude of the deflections of the roof in the model of the plate concerning the model of the beam reach 5%, which is acceptable for mining problems. Scientific novelty. To study the bending deformations and determine the magnitude of the roof deflection in models under external uniform distributed load, placed within the simulated plate, a strip of unit width was selected, which has a symmetrical cross-section and is a characteristic component of the plate structure and it is considered as a separate load-bearing element with supports, the cross-sections of this element is remained flat when bending. The deflection of such a linear element is described by the differential equations of the bent axis of the beam without taking into account the integral stiffness of the model, and the vector of its complete displacement coincides with the vector of the force line. Practical significance. In the laboratory, to study the bending deformations and their impact on the stability of the coal seam roof under external loads, it is advisable to use a model of a single width beam with a symmetrical section with supports, the type of which is determined by rock pressure control and secondary support of the maingate at the extraction layout of the coal mine.

scholarly journals Stability of Wheat Genotypes by AMMI and Yield Evaluated under Peninsular Zone of India

2021 ◽  
Author(s):  
Ajay Verma ◽  
G.P. Singh
Keyword(s):  
Weighted Average ◽  
Principal Component ◽  
Efficient Estimation ◽  
High Yield ◽  
First Year ◽  
Wheat Genotypes ◽  
Stability Measure ◽  
Linear Behaviour ◽  
The Stability ◽  
Selection Of

Background: Efficient estimation of main and interaction effects under multi environment trials had been carried out by AMMI. Studies with low proportion of the variance explained by first interaction principal component IPCA1 under AMMI analysis had been reported biased interpretation for the stability of the genotypes.Methods: Weighted Average of Absolute scores (WAASB), quantitative stability measure had been recommended for selection of productive genotypes with broad adaptation. The selection of promising genotypes had been assisted by use of superiority index (WAASBY) that considered simultaneous use of yield and stability by allowing variable weighting mechanism for yield and stability.Result: Wheat GW509 and HI1633 genotypes had been identified by stability measure WAASB for the first year. While Superiority index considered stability and high yield settled for HI1633 and Raj4083 genotypes. Analytic measures of adaptability PRVG and MHPRVG observed suitability of HI1633 and Raj 4083. SI expressed positive linear behaviour with yield, MHPRVG and PRVG measures. While stability measure WAASB maintained moderate negative correlation with yield, SI, MHPRVG and PRVG. Wheat genotypes HI1633, HI1641 and HI1646 identified by stability measure for the next year of study. Superiority index selected HI1641, HI1633 and MACS6752 genotypes. SI expressed direct linear relation with yield, MHPRVG and PRVG. Stability measure exhibited indirect relationships with SI, MHPRVG, PRVG and yield Wheat genotypes HI1633, Raj 4083 for first year and HI1641, MACS6752 for the second year of study.

scholarly journals Surrounding Rock Movement of Steeply Dipping Coal Seam Using Backfill Mining

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Wenyu Lv ◽  
Kai Guo ◽  
Jianhao Yu ◽  
Xufeng Du ◽  
Kun Feng
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Surrounding Rock ◽  
Maximum Deflection ◽  
Coal Seams ◽  
Physical Similarity ◽  
Working Face ◽  
Rock Structure ◽  
Backfill Mining ◽  
The Stability

The movement of the overlying strata in steeply dipping coal seams is complex, and the deformation of roof rock beam is obvious. In general, the backfill mining method can improve the stability of the surrounding rock effectively. In this study, the 645 working face of the tested mine is used as a prototype to establish the mechanical model of the inclined roof beam using the sloping flexible shield support backfilling method in a steeply dipping coal seam, and the deflection equation is derived to obtain the roof damage structure and the maximum deflection position of the roof beam. Finally, numerical simulation and physical similarity simulation experiments are carried out to study the stability of the surrounding rock structure under backfilling mining in steeply dipping coal seams. The results show the following: (1) With the support of the gangue filling body, the inclined roof beam has smaller roof subsidence, and the maximum deflection position moves to the upper part of working face. (2) With the increase of the stope height, the stress and displacement field of the surrounding rock using the backfilling method show an asymmetrical distribution, the movement, deformation, and failure increase slowly, and the increase of the strain is relatively stable. Compared with the caving method, the range and degree of the surrounding rock disturbed by the mining stress are lower. The results of numerical simulation and physical similarity simulation experiment are generally consistent with the theoretically derived results. Overall, this study can provide theoretical basis for the safe and efficient production of steeply dipping coal seams.

Estimation of burnt coal seam thickness in central Borneo using JERS-1 SAR data

2003 ◽  
Vol 24 (4) ◽  
pp. 879-884 ◽  
Author(s):  
J. Tetuko S. S. ◽  
R. Tateishi ◽  
N. Takeuchi
Keyword(s):  
Coal Seam ◽  
Seam Thickness ◽  
Sar Data ◽  
Coal Seam Thickness
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