Time and motion study of dumpers and shovel deployed at a shallow depth mine

Jan 2018 / by Debasis Deb and Sreenivasa Rao Islavath

A friable chromite ore body in Sukinda valley, Odisha is being excavated by opencast mining method. Combination of shovel and dumper system is deployed to lift overburden rock and ore body to the dump yard and ore handling plant respectively. Dumpers carrying overburden rocks travel from loading points in the pit to dump yard and others carrying ore travel to ore handling plant for unloading the material and return. A time-and-motion study has been undertaken to understand the pattern of fuel consumption of loaded and empty dumpers so that a proper economical analysis can be carried out while offloading this work to contractors. In this paper, a methodology is established to determine the fuel consumption of loaded dumper for (i) lifting the material from the loading points to the pit top, (ii) traveling of loaded dumper on the surface from pit top to discharge point, (iii) travelling of empty dumpers from discharge point to pit top and (iv) travelling of empty dumpers from pit top to the loading points. In addition, the cycle time and waiting time of shovels are also collected and analyzed based on the different probability distribution functions.

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Evaluation of soil erosion risks in a coal mine based on an integrated extension-cloud model

Jan 2018 / by Li Li, Qiang Yue and Li Shaohong

Soil and water losses have become a serious ecological and environmental problems, and how to scientifically carry out soil and water losses risk assessment on soil erosion prevention and treatment of macroeconomic decisionmaking are very important. Based on the concept of cloud matter element, the associated function and cloud model were used to calculate the association value, then an improved matter-element model of extension cloud combination was established, at last, the evaluation model was introduced into soil and water losses risk assessment. Through the project case in a coal mine shows that the improved evaluation model can get a reasonable risk evaluation result. In practical application, the evaluation result of the extension cloud combination model constructed by classical extension correlation function is closer to the visual statistical value.
Keywords: Fextenics, cloud model, cloud matter element, a coal mine, soil and water losses evaluation

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Phase behaviour and development scheme of near-critical gas condensate reservoir

Jan 2018 / by Bin Nie and Er-peng Li

Combined with fluid data of J gas reservoir in Africa, the phase characteristics of near-critical gas condensate reservoir were studied, and the applicable development technique were analyzed using reservoir numerical simulation. The results show that the near-critical gas has the following characteristics. It has a high content of condensate oil, the sensitivity of phase is strong, and the degree of retrograde condensation is high. Depletion type of recovery results in great loss of condensate oil and poor production, the method of water-oil alternating recovery could control the level of condensate effectively and get a high oil production rate. In addition, it avoids the rising up of water cut too early and quickly in the method of water flooding. Water-oil alternating recovery is the best producing method which combined the advantages of water injection and gas injection. Further study on sensible factors in water-oil alternating recovery indicates that the water/ gas ratio (WGR) has the greatest impact on production effect. When the WGR is too high, injected water will rush into the well bottom too early; when the WGR is too low, the advantage of water injection to displace and provide pressure is lost, and condensate oil production rate cannot be enhanced.
Keywords: Gas condensate reservoir, near-critical, phase behaviour, water-oil alternating recovery

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Key technologies of tight gas reservoir prediction controlled by time-equivalent geological horizons

Jan 2018 / by Yutan Dou, Huaqing Liu, Mengli Zhang and Menggang Zhang

It gets more and more attention for the low permeability tight gas reservoir exploration and development. As we know, resources of tight gas reservoirs in Sichuan basin are very rich, but there are many problems about seismic exploration to the tight sandstone gas reservoirs, especially application of effective reservoir prediction and fluid detection. Therefore, it is one of the points for tight sandstone gas exploration and development that how to find gas reservoirs with the value of industrial productions (sweet spot). Based on the geological features of tight gas reservoirs in Xujiahe of center Sichuan basin, analysis of rock physics and logging interpretations, this paper conducted AVO analysis and analyzed and selected lithology sensitive parameters, and then identified parameters of lithology and hydrocarbon. Moreover, we marked angle limited pre-stack seismic data with calibrated well loggings by seismic-well tie and studied the timeequivalent data. Controlled by time-equivalent geological horizons and rock physics characters, we established the key technologies of effective reservoir prediction and fluid detection in this areas, which are combination of pre-stack reservoir prediction techniques, such as pre-stack elastic parameters crossplot based on “S-wave virtual wells” and lithological facies fluid probability analysis, and fluid detection techniques, such as highlight volumes analysis and pre-stack attenuation in angle domain. The results of drilled wells show our good recommendation for well locations and prove that we accurately predicted the favourable gas reservoir distribution in Xujiahe formation of center Sichuan Basin.

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Structural invulnerability evaluation of complex multi-layer emergency logistics system based on interdependent network theory

Jan 2018 / by Chang Chen, Jikun Guo, Qixin Zhang, Shifu Zhang, Yi Wang and Tengfei Zhang

Emergency logistic system is quite important for natural disaster recue and other unexpected incidents treatment. At present, most relative modelling and analyzing research on logistic network invulnerability is based on a single network, and does not take the interaction between networks into account. This paper proposes the complex multi-layer logistic model consists of command control network, space communication network and physical transportation network based on interdependent network theory. The result of network invulnerability research shows that the three-layer interdependent network model is more precisely and conform to the actual situation of emergency logistic system operation. Moreover, the invulnerability evaluation method proposed in this paper is more accurate and detailed than the traditional method. This conclusion can provide references for the designing of emergency logistics system with better invulnerability and applied to other areas research.
Keywords: Invulnerability evaluation; multi-layer system; emergency logistics; interdependent network theory

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Investigations into the influence of decking on rock fragmentation and ground vibrations by blasting in shallow benches of limestone quarries – a case study

Jan 2018 / by P. Balamadeswaran, Arvind Kumar Mishra, Phalguni Sen and S. Ramesh

In any quarry blasting, rock breakage is considered to be one of the significant components for carrying out the ground preparation to achieve higher production rate and also to sustain productivity. However, the performance of the blasting in terms of controlling environmental effects and the costs involved in the operation determine the profitability and sustainability of the mining company to huge extent. Thus it is necessary to study the existing conditions and accordingly implement the cost-effective technique which may enhance the blast performance with minimizing the environmental effects. Here, the decking practice in the blastholes is one of such costeffective techniques, which is being considered to improve the blast results in the form of improvised fragmentation, effective throw, reduced vibration and less back break. Therefore, a case study involving the deep hole blasts carried out with conventional decking practice in the shallow benches of a limestone quarry located in the state of Tamil Nadu. Using the image analysis software – Fragalyst 4.0, the images of blasted muckpile were then analyzed to determine the mean fragment size and the size distribution of the fragments. It was observed that the deck blasting technique is found to be economical and also reduces the ground vibration considerably. This paper discusses the decking practices that are developed and subsequently implemented in the quarry blasting and finally outlines the recommendations to be taken for improving the performance of blasts in shallow benches of the quarry.
Keywords: Blast design, geology,decking, fragmentation, ground vibration, back break

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Generation and validation of cartosat-1 DEM for northern Aravali range of hillocks, Rajasthan, India

Jan 2018 / by Md. Soyeb Alam, Dheeraj Kumar and Vijay Upreti

Digital Elevation Model (DEM) is a spatial representation of any area or surface in the form of three dimensions (x,y,z) represent the height of the individual points (pixels) of the surface along with x and y rectangular coordinates.DEM is widely used to extract the information from many areas like subsidence/deformation monitoring, updating and preparation of drainage pattern, hydrology and water resource management etc. The selection of DEM (on the basis of accuracy) plays an important role while using it for any particular application. In some application area accuracy of DEM is not a matter of great concern. However, in some application, accuracy of DEM plays a very vital role to derive the required result.. In this study, area of interest belongs to a mineral rich zone, coming under the Khetri copper belt, a part of Northern Aravali range of hillocks in India. This particular belt is predominant with mining activities since late 1960’s. Keeping in view of deformation studies in such area using conventional DInSAR technique, accuracy of DEM (normal baseline > 200 m), should be in higher side to eliminate the local topographic phase completely. Keeping in view of above background, DEMs (relative and absolute) were generated from high resolution Cartosat-1 stereo pair dataset (IRS) using GCPs, without GCPs and GCPs collected with the help of Google Earth. RMS error obtained from different techniques were compared along with SRTM DEM (3 arc second).Vertical accuracy in terms of RMS error has been found in the order of 2.54m, 10.10m, 37.97m and 76.66m for Carosat-1 DEM (GCP collected from GNSS), SRTM, Cartosat-1DEM (without GCP) and Cartosat-1 DEM (GCP collected from Google Earth) respectively.

Validation of high accuracy DEM has been demonstrated in DInSAR processing (using ALOSPALSARSLC dataset) to eliminate topographical phase of the study area.

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