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Underground mine stream crossing assessment:A multi-disciplinary approach

International Journal of Mining Science and Technology 2021年第1期31卷 59-65页

作者： Kevin Andrews Steve Keim marshall miller&associates BluefieldVA 24605USA

Underground mine designs typically try to avoid extraction beneath streams and rivers of any significant size,especially when the overburden rock thickness between the stream bed and the mine is *** issues with mining beneath streams include excessive groundwater inflow to the mine,weak ground(roof,floor,and pillar)conditions,horizontal stress effects,as well as stream loss and other potential adverse environmental ***,there are times when crossing beneath a stream or river is necessary to move into a new area of mineral reserve without creating additional mine access points from the ground ***,stream crossings are completed without thorough assessment,potentially resulting in increased costs,decreased safety,and,in some cases,failure to advance the *** of the most favorable location(s)to cross the stream must account for numerous factors and the associated assessment often requires a multi-disciplinary *** crossing investigations often require geological,hydrogeological,geotechnical,and geophysical *** of stream crossing investigations include desktop evaluation of maps and aerial photography,stream bed observations,drilling,detailed rock core logging,downhole geophysical surveying,hydraulic conductivity testing(packer testing),geotechnical laboratory testing,assessment,and *** deliverables from a stream crossing assessment typically include geological,geotechnical,and hydrogeological characterization of potential stream crossing locations,classification of favorable and unfavorable crossing locations,recommendations for entry design and pillar sizing,and recommendations for if,and how,to conduct pre-grouting *** of technical aspects of data collection and assessment are provided based on decades of industry experience conducting stream crossing assessments in various underground mining scenarios.

关键词： Underground mining Geotechnical Stream-crossing Hydrogeology Characterization

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Fundamental behaviours of production traffic in underground mine haulage ramps

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International Journal of Mining Science and Technology 2015年第1期25卷 7-14页

作者： Haviland David marshall Joshua Golder associates Ltd. The Robert M. Buchan Department of Mining Queen’s University

Ramps(or declines) are often used in underground mines to transport ore, waste, materials, and personnel. This paper studies mine ramp productivity and presents results from a set of computer simulations designed to model the fundamental behaviours of ramp haulage systems. Simulations show that, under fundamental assumptions without random disturbances, the haulage system always converges to a periodic behaviour in the steady state, but that productivities vary between equilibria. Simulations also demonstrate how productivity per vehicle does not necessarily decrease as more vehicles are added and,for example, in the five-vehicle case, how a 3.1% improvement can be achieved over the use of four vehicles. The result reveals the inefficiency of commonly-used lockout-style vehicle coordination strategies,and suggests a possible avenue for improving the productivity of haulage ramps by controlling the system to achieve more productive behaviours.

关键词： Underground miningFleet managementDiscrete-time simulationVehicle dispatching

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A multilocus molecular phylogeny for the avian genus Liocichla(Passeriformes:Leiothrichidae:Liocichla)

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Chinese Birds 2015年第3期6卷 140-152页

作者： Herman L Mays Bailey D Mc Kay Dieter Thomas Tietze Cheng-Te Yao Lindsey N miller Kathleen N Moreland Fumin Lei Department of Biological Sciences Marshall University Cincinnati Museum Center American Museum of Natural History Institute of Pharmacy and Molecular Biotechnology Heidelberg University Endemic Species Research Institute Biotechnology Program Loveland High School Institute of Zoology Chinese Academy of Sciences

Background:Historically the babblers have been assigned to the family Timaliidae but several recent studies have attempted to rest the taxonomy of this diverse passerine assemblage on a more firm evolutionary *** result has been a major rearrangement of the group.A well?supported and comprehensive phylogeny for this widespread avian group is an important part of testing evolutionary and biogeographic hypotheses,especially in Asia where the babblers are a key component of many forest ***,the genus Liocichla is poorly represented in these prior studies of babbler ***:We used a multilocus molecular genetic approach to generate a phylogenetic hypothesis for all five cur?rently recognized species in the avian genus *** DNA sequence data was used to construct individ?ual gene trees using maximum likelihood and species trees were estimated from gene trees using Bayesian *** dates were obtained using a molecular clock ***:Molecular data estimate a probable window of time for the origin for the Liocichla from the mid to late Miocene,between 5.55 and 12.87 *** plumage similarities between the insular Taiwan endemic,***,and the continental *** and ***,molecular data suggest that *** is the sister taxon to all continen?tal *** continental Liocichla are comprised of two lineages;a lineage containing *** and *** and a lineage comprised of *** and *** comparatively early divergence of *** within the Liocichla may be illusory due to extinct and therefore unsampled *** and *** are parapatric with a Pleistocene split(0.07–1.88 Ma) occurring between an Eastern Himalayan *** and a Northern Indo?china distributed *** and *** underwent a similar split between the Eastern Himalaya(***) and Central China(***) divided by the Hengduan ***

关键词： Biogeography Himalayas Leiothrichidae Liocichla Phylogenetics Phylogeography Taiwan

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Impact of Compaction Mode on Strength Properties of Sustainable Asphalt Concrete

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Journal of Architectural Environment & Structural Engineering Research 2021年第4期4卷 3-9页

作者： Saad Issa Sarsam Sarsam and associates Consult Bureau SACB BaghdadIraq

Various modes of compacting the asphalt concrete mixture can create mechanically different behaviour of the prepared specimens and can alter its *** attempt has been made in the present assessment to prepare asphalt concrete specimens by implementation of three modes of compaction,the gyratory,the roller,and the marshall *** specimens were prepared at the target bulk density of marshall method at optimum asphalt *** specimens were prepared at 0.5%asphalt below and above the *** specimens have been obtained from the roller compacted slab *** specimens were tested for the marshall stiffness,tensile,and shear *** was observed that at optimum asphalt content,the indirect tensile strength declines by(18.8 and 70.5)%for gyratory and roller compacted specimens respectively as compared with hammer compacted *** optimum asphalt content,the shear strength declines by(70.5 and 82.2)%while marshall stiffness declines by(10.2 and 44.8)%for hammer and roller compacted specimens as compared with that of gyratory compacted *** prepared by gyratory compaction are less susceptible to the change in the testing temperature as compared with other modes of *** is recommended to consider the mode of compaction to suit the required design property of sustainable asphalt concrete mixture.

关键词： Sustainable asphalt concrete Compaction mode Tensile Shear strength marshall stiffness

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