A comparative study on kinetics and dynamics of two dump truck lifting mechanisms using MATLAB simscape

In this paper,two lifting mechanism models with opposing placements,which use the same hydraulic hoist model and have the same angle of 50°,have been developed.The mechanical and hydraulic simulation models are established using MATLAB Simscape to analyze their kinetics and dynamics in the lifting and holding stages.The simulation findings are compared to the analytical calculation results in the steady state,and both methods show good agreement.In the early lifting stage,Model 1 produces greater force and discharges goods in the container faster than Model 2.Meanwhile,Model 2 reaches a higher force and ejects goods from the container cleaner than its counterpart at the end lifting stage.The established simulation models can consider the effects of dynamic loads due to inertial moments and forces generated during the system operation.It is crucial in studying,designing,and optimizing the structure of hydraulic-mechanical systems.

Shear resistance characteristics and influencing factors of root-soil composite on an alpine metal mine dump slope with different recovery periods

Artificial vegetation restoration is the main measure for vegetation restoration and soil and water conservation in alpine mine dumps on the Qinghai-Tibet Plateau,China.However,there are few reports on the dynamic changes and the influencing factors of the soil reinforcement effect of plant species after artificial vegetation restoration under different recovery periods.We selected dump areas of the Delni Copper Mine in Qinghai Province,China to study the relationship between the shear strength and the peak displacement of the root-soil composite on the slope during the recovery period,and the influence of the root traits and soil physical properties on the shear resistance characteristics of the root-soil composite via in situ direct shear tests.The results indicate that the shear strength and peak displacement of the rooted soil initially decreased and then increased with the increase of the recovery period.The shear strength of the rooted soil and the recovery period exhibited a quadratic function relationship.There is no significant function relationship between the peak displacement and the recovery period.Significant positive correlations(P<0.05)exists between the shear strength of the root-soil composite and the root biomass density,root volume density,and root area ratio,and they show significant linear correlations(P<0.05).There are no significant correlations(P>0.05)between the shear strength of the root-soil composite and the root length density,and the root volume ratio of the coarse roots to the fine roots.A significant negative linear correlation(P<0.05)exists between the peak displacement of the rooted soil and the coarse-grain content,but no significant correlations(P>0.05)with the root traits,other soil physical property indices(the moisture content and dry density of the soil),and slope gradient.The coarse-grain content is the main factor controlling the peak displacement of the rooted soil.

Rainfall-triggered waste dump instability analysis based on surface 3D deformation in physical model test

Landslide is the second largest natural disaster after earthquake. It is of significance to study the evolution laws and failure mechanism of landslides based on its surface 3D deformation information. Based on the rainfall-triggered waste dump instability model test, we studied the failure mechanisms of the waste dump by integrating surface deformation and internal slope stress and proposed novel parameters for identifying landslide stability. We developed a noncontact measurement device, which can obtain millimeter-level 3D deformation data for surface scene in physical model test;Then we developed the similar materials and established a test model for a waste dump. Based on the failure characteristics of slope surface, internal stress of slope body and displacement contours during the whole process, we divided the slope instability process in model test into four stages: rainfall infiltration and surface erosion, shallow sliding, deep sliding, and overall instability. Based on the obtained surface deformation data, we calculated the volume change during slope instability process and compared it with the point displacement on slope surface. The results showed that the volume change can not only reflect the slow-ultra acceleration process of slope failure, but also fully reflect the above four stages and reduce the fluctuations caused by random factors. Finally, this paper proposed two stability identification parameters: the volume change rate above the slip surface and the relative velocity of volume change rate. According to the calculation of these two parameters in model test, they can be used for study the deformation and failure mechanism of slope stability.

A Predictive Energy Management Strategies for Mining Dump Trucks

The plug-in hybrid vehicles(PHEV)technology can effectively address the issues of poor dynamics and higher energy consumption commonly found in traditional mining dump trucks.Meanwhile,plug-in hybrid electric trucks can achieve excellent fuel economy through efficient energy management strategies(EMS).Therefore,a series hybrid system is constructed based on a 100-ton mining dump truck in this paper.And inspired by the dynamic programming(DP)algorithm,a predictive equivalent consumption minimization strategy(P-ECMS)based on the DP optimization result is proposed.Based on the optimal control manifold and the SOC reference trajectory obtained by the DP algorithm,the P-ECMS strategy performs real-time stage parameter optimization to obtain the optimal equivalent factor(EF).Finally,applying the equivalent consumption minimization strategy(ECMS)realizes real-time control.The simulation results show that the equivalent fuel consumption of the P-ECMS strategy under the experimentally collected mining cycle conditions is 150.8 L/100 km,which is 10.9%less than that of the common CDCS strategy(169.3 L/100 km),and achieves 99.47%of the fuel saving effect of the DP strategy(150 L/100 km).

Volume and Toxic Composition of Leachate from an Open Dump

In Mexico, hazardous and non-hazardous urban solid wastes are commonly disposed of in dumps. Inappropriate waste disposal makes solid waste disposal sites potential sources of pollution and health risks. The objective of the present study was to evaluate the impact of leachate from a dump on surface water systems. Physical, chemical, and bacteriological characteristics and the volume of leachate were measured. The site of study is located in Zinaprcuaro, Michoac^m, Mexico, and was chosen due to the water supplies were in line with the dump, thus conforming a system to test for movement of toxins. Leachate and water from three ponds located at different distances to the dump were sampled during three months of a year to measure physicochemical and bacteriological parameters, according to the standard methods of the American Public Health Association; the concentration of heavy metals was measured by atomic absorption spectrometry. Most characteristics exceed the maximum permissible limits established for the Mexican legislation regarding wastewater discharges and drinking water. Likewise, analysis of variance showed statistically significant differences between concentrations of pollutants in relation to the distance from the dump of sampled sites and with season of sampling, thus confirming the contamination of water by dump leachate.

600WM汽轮机高压主汽门及高压调门DUMP阀故障分析与处理

介绍了DUMP阀的作用、结构原理,结合某电厂高压主汽门、高压调门几次故障案例,分析研究DUMP阀发生故障的原因,并提出相应的处理措施,为类似问题的解决提供了参考和借鉴。

Legacy Gold Mine Sites & Dumps in the Witwatersrand: Challenges and Required Action

Legacy mine shafts and waste dumps in the Witwatersrand continue to create social and environmental challenges for communities, even in areas where gold mining ceased over 100 years ago. The slow pace of eradication of these gold mine shafts and waste dumps (or lack thereof) results in conflict between the communities and authorities, particularly the Department of Mineral Resources and Energy (DMRE) as the relevant authority in the field of environmental management in mining. This paper examines, through a literature review, the past and present legislative framework that resulted in legacy mine shafts and dumps and how communities find themselves living next to these mine sites, which results in social and environmental problems. The paper further explores the governments, particularly the DMRE, proposed initiatives to empower those who intend to extract value from the abandoned mines while curbing the scourge of crime in affected communities.

Cycle Time Analysis of Open Pit Mining Dump Trucks

This study demonstrates a practical cycle time analysis of dump truck haulage system of “Ukhaa Khudag” open-pit coal mine located in Umnugobi Province, Mongolia. It examines the possibility of minimizing the cycle time of the haulage system as well as factors impacting the speed of the dump truck. The current study divides the open pit mine road for the dump trucks into five sections which are bench road, ramp, surface road, dump road uphill, and dump road. Meanwhile, it investigates the influence of the length, the grade, and the rolling resistance of the road section on the cycle time. The data is analyzed using mathematical regression methods via Microsoft Excel program. For each of the five road sections, we compare the statistical calculations of three regression models: linear, quadratic and exponential;thus, a total of thirty regression models are obtained in this research. Accordingly, the cycle time for each road section is predicted by the most accountable model. The loaded and empty direction of the movement is measured and calculated for each road section, and it appears that the difference between the calculated mean value and the actual cycle time of the models is 0.82 seconds with a relative error of 2.51 percent.

中国荷斯坦公牛CN和DUMPS遗传缺陷检测及系谱分析

旨在研究中国荷斯坦牛中瓜氨酸血症(Citrullinemia,CN)和尿苷酸核酶缺乏症(Deficiency of uridinemonophosphate synthase,DUMPS)2种遗传缺陷的携带者比率及系谱来源,并构建更简便的检测方法。本研究通过PCR-RFLP方法对参加我国联合青年公牛后裔测定和良种补贴项目的591头荷斯坦公牛进行了大规模CN和DUMPS的遗传缺陷检测,并构建了奶牛CN隐性有害基因的AS-PCR检测技术。结果,共发现2头CN和1头DUMPS隐性有害基因携带者公牛,携带者比例分别为0.34%和0.17%。经过系谱追溯,2头CN携带者公牛均为澳大利亚公牛Linmack Kriss King-CN后代,DUMPS携带者公牛为美国公牛Skokie sensation Ned后代。基于此,我国有必要尽快建立荷斯坦牛隐性遗传缺陷监控体系并进行系谱标注,通过青年公牛预选和选种选配,避免携带者公牛进入后裔测定和良种补贴项目,以逐步降低我国奶牛群体中隐性有害等位基因频率。

天津地区荷斯坦公牛CVM、DUMPS和CN遗传缺陷检测

本文旨在研究天津地区中国荷斯坦公牛脊椎畸形综合征(Complex?vertebral?malformation,CVM)、尿苷酸合酶缺乏症(Deficiency?of?uridine?monophosphate?synthase,DUMPS)和瓜氨酸血症(Citrullinemia,CN)3种遗传缺陷的携带者比率及系谱来源。通过PIRA-PCR和PCR-RFLP方法分别对天津奶牛发展中心参加全国青年公牛联合后裔测定和国家良种补贴项目的110头荷斯坦公牛进行了CVM、DUMPS和CN三种遗传缺陷检测。共发现6头CVM隐性有害基因携带公牛,携带者比例为5.45%,隐性有害等位基因频率为2.72%。经过系谱分析,其中4头CVM携带者均为美国公牛Carlin-M?Ivanhoe?Bell的后代,另外2头因系谱不完整而无法查询。未检测到DUMPS和CN隐性有害基因携带者。基于此,我国有必要尽快建立荷斯坦牛隐性遗传缺陷监控体系并进行系谱标注,避免携带公牛进入后裔测定和良种补贴项目,以逐步降低我国奶牛群体中遗传缺陷隐性等位基因频率。

Release characteristics and stabilization of heavy metals in antimony tailings in Yunnan Province,China

The pollution caused by the mining and smelting of heavy metals is becoming an increasingly severe environmental problem.In this study,the environmental risks of mine tailings were explored using typical antimony tailings(the depth of the sample taken from the ground to the deepest position of 120 cm)from the Zuoxiguo mine in Yunnan Province,Southwest China.The tailings were examined to explore the geological background,distribution characteristics,and release characteristics of heavy metals.Additionally,stabilizer treatments for heavy metals were investigated in consideration of waste treatment.The results showed that the contents of Sb and As(8.93×103 and 425 mg/kg,respectively)in the tailings were considerably higher than the local soil background values,suggesting that these metals pose a considerable threat to the surrounding environment.The geological background values of Cr,Cd,Pb,Cu,and Zn were relatively low.The results of static release showed that Sb,As,Cd,and Cr leached from the tailings more easily than Cu,Zn,and Pb under acidic conditions(pH=2.98).Geo-accumulation indices and potential ecological risk indices showed that Sb,As,Cd,and Pb were highly enriched in the tailings,whereas Cu,Cr,and Zn contents were relatively low.The single factor ecological risk index of the mining area showed that Sb and As are high ecological risk factors,whereas Cr,Cu,Zn,Cd,and Pb are not.The results of the orthogonal test results showed that by adding 15.0%(m/m)fly ash and 15.0%(m/m)zeolite powder to the quicklime and curing for 28 d,a significant stabilization effect was observed for Sb,As,and Pb.This study helps determine the priority control components for characteristic heavy metals in antimony tailings,and provides valuable insights regarding the formulation of appropriate mitigation strategies.

EFFECT OF DUMP GAP ON TOTAL PRESSURE LOSS IN DUMP DIFFUSER

The dump diffuser is an important component in advanced annular combustor, and its performance affects greatly the fluid field and pressure loss of the combustor. This paper presents the characteristics of the total pressure loss. Experiments and numerical simulations, keeping the inlet March number of prediffuser constant ( Ma =0 20), are carried out to obtain the regularity of the total pressure loss. It varies with the relative dump gap ( δ =1 2～3 0)by changing the position of prediffuser and combustor liner, respectively. Research shows that there exists the minimum total pressure loss ( σ *=1 6%～1 75%) when relative dump gap δ is about 1 8.

Linux Crash Dump的设计与实现

本文介绍了Linux Crash Dump的设计与实现方法。Linux Crash Dump提供了一种保存系统在发生Crash时内存映象的能力。通过对Dump结果的分析,可以有效地帮助诊断系统出错的原因。本文介绍了如何进行Crash Dump,以及Dump的数据的组织和保存方法等。

Dump技术在Solaris系统恢复中的应用研究

对Solaris操作系统核心部分、数据文件部分的备份和恢复方法进行了描述,论述了Dump技术在Solaris系统恢复中的应用。分析表明,Dump技术是Solaris操作系统恢复技术中最为快捷有效的方法之一,它可以使系统快速地恢复正常,保证系统的稳定运行。

Innuendoes of Sterilisation Drilling in Surface Mining Operations—A Case Study

Surface mining operations play a crucial role in meeting the world’s increasing demand for mineral resources for the advancement of technology and debauched expansion of economies. The search for and exploitation of these mineral resources are therefore important for the sustainability of the mineral extraction industry. To this end, efficient mine planning must incorporate sterilisation drilling and effective waste rock management principles in the search and exploitation of these minerals. In this article, sterilisation drilling is being reviewed vis-a-vis the establishment of waste and tailings dump locations, backfilling of open pit excavations and mine closure giving critical attention to the minerals and mining laws of Ghana. Subsequently, a detailed case study of a surface mining operation that successfully incorporated sterilisation drilling in determining waste dump location in its mine planning process has been presented in this study. The findings indicate that the proposed waste dump location could present a potential mining prospect in the future based on enhanced milling capacity/technology and improved mineral commodity price;underscoring the significance of sterilization drilling in the sustainability of the mining industry.

劫持Linux系统调用封杀Core Dump漏洞攻击

Core Dump漏洞影响kernal2.6.13-2.6.17.3的多款Linux操作系统,它可以引发拒绝服务攻击和本地权限提升攻击,危害巨大。恶意进程使用prctl系统调用,通过故意制造Core Dump,可以旁路操作系统安全控制,攻击系统。通过劫持prctl系统调用,对发起系统调用的进程进行行为监视,进而检测攻击,可以有效地阻止和防御攻击的发生。把防御程序编译为可动态插入内核的模块,能在多款受影响的系统上稳定高效地运行。

Prospects of utilization of waste dumped low-grade limestone for iron making: A case study

Low grade dumped limestone sample having high silica of 8.1%, 36.8% CaO, and 3% Al2O3 has been studied with the aim to reduce the silica level to below 3% for its utilization in iron making. Beneficiation study of the sample was initiated with desliming of the feed sample of -100 μm to remove the siliceous ultrafine particles and to improve the feed quality. Flotation study was carried out by column flotation technique varying the collector dosage, superficial air flow velocity and froth depth to assess their effect on silica reduction and CaO recovery. It was observed that increased collector dosage and superficial air velocity increases the recovery of CaO, and increase in the froth depth reduces the mass flow and silica content in the concentrate. The best result was found at 1.25 cm/sec superficial air velocity, 25 cm froth depth, 1.25 kgpt collector dosage and concentrate assayed 47.3% CaO, 2.8% silica with 72% CaO recovery.

Natural vegetation recovery on waste dump in opencast coalmine area

The changes of vegetation compositions, plant species diversity, species important value and succession of plant community were studied on waste dumps in Haizhou opencast coalmine which is located in the west of Liaoning Province, China (41°41(-42°56( N, 121°1(-122°56(E). Four kinds of terraces with different ages (5, 10, 20 and 40 years) were selected for investigation of plants. Total of 63 species of natural colonized plants were recorded on the waste dump and they belong to 23 families. The main families were Compositae (15 species), Fabaceae (11 species) and Leguminosae (8 species), which accounted for 54.0% of total species and play an important role in natural vegetation recovery in waste dump area. The dominant species on 5-, 10-, 20-, 40-year-old terraces were Tribulus terrestris + Echinochloa hispidula + Salsola collina, Echinochloa hispidula + Artemisia sieversiana + Artemisia scoparia, Echinochloa hispidula + Clinelymus dahuricus + Artemisia scoparia + Artemisia sieversiana + Melilotus officinalis, Clinelymus dahuricus+Phragmites communis + Echinochloa hispidula+ Setaria viridis, respectively. According to the important value of species calculated. It is determined that Tribulus terrestris can act as pioneer species on waste dump and Clinelymus dahuricus, Phragmites communis and Echinochloah hispidula are important dominant species in vegetation restoration in Haizhou opencast coalmine. The study results can provide scientific basis for selecting and disposing appropriately plant species and rehabilitating vegetation on waste dumps of coalmine.

Discrete element approach for mine dump stability analysis

Mine overburden dumps have posed significant safety issues in the operations of various unit operations of open pit min-ing especially the external dumps. The external dumps are composed of a mixture of fragmented rocks and loose soil. Their charac-teristic is comparable to heavily discontinuous solid mass. The conventional approach of limit equilibrium methods provide safety factors for the slope but nothing about the stress-strain characteristics of the large dump mass. The designs of dump location and their respective geometry are integrated for the know-how of the stability characteristics of these dumps. The discrete element method uses a circular disk to represent the granular solid mass and their interactions are described by the Newton’s third law of motion. The displacement is described by the sliding of the circular disk. This work is focused on the modeling efficiency of the discrete element methods to represent the behaviour of mine dump masses with the specified joint plane for the limit equilibrium method. The advantage of the work lies on the ease of information retrieval at any point at the dump mass concerning the stress and strain histories, displacement, failures etc. which when integrated produces a better understanding of the stability of the dump masses.

Stability of inner dump slope under coal pillar support:case study in an open‑pit coal mine

The stability of an inner dump slope was investigated under the efect of coal pillar support considering the development position of dumping.Based on the instability mechanism and load distribution characteristics of the supporting coal pillar,the three-dimensional mechanical efects of the supporting coal pillar are characterized.Using the two-dimensional equivalent principle and the residual thrust method,the stability of the inner dump slope was analyzed under the efect of pillar support at diferent dump development positions.The quantitative efects of various factors on the inner dump slope stability were revealed,and the coal pillar shape parameters were optimized through numerical simulations.The results indicate that the slope stability coefcient is linearly related to the top width and height of the coal pillar,slope angle,and base inclination angle,and has an exponential relation with the coal pillar strike length and slope height increment.There are quadratic and absolute value relations with the coal pillar outer and the inner bottom angle,respectively.The top width of the coal pillar in the inner dump of Shengli East No.2 open-pit coal mine should be at a level of+824 m,and the optimal top width and height are 15 and 36.7 m,respectively.The instability mechanism of the supporting and retaining coal pillar obtained by numerical simulations and the stability of the inner dump are in good agreement with the theoretical analysis.Our results provide a theoretical basis for the design,treatment,and safe implementation of similar open-pit mine slope engineering.