A Practical Approach to Mine Equipment Sizing in Relation to Dig-Limit Optimization in Complex Orebodies: Multi-Rock Type,Multi-Process,and Multi-Metal Case     

Julian Ramirez Ruiseco  Mustafa Kumral 《Natural Resources Research》2017,26(1):23-35

Equipment sizing is a developed field of mining engineering, which considers all aspects related to productivity, and grade distribution. Current methods of equipment sizing consider block dilution, but do not analyze the impact of the selectivity changes on practical dig-limits. This research analyzed the impact of varying equipment sizes on a highly variable three destination, Au and Cu bench, in a sulfide/oxide deposit. The study shows that selectivity sizing profit and size relationships are nonlinear, and exhibit severe break points if insufficiently selective equipment is used. The proposed technique can be used for sizing mine equipment in complex deposits.  相似文献   

REE fractionation and Ce anomalies in weathered Karoo dolerite   总被引：1，自引：0，他引：1  

Julian S. Marsh 《Chemical Geology》1991,90(3-4):189-194

Analyses of samples from a weathering profile on Karoo dolerite allow elements to be divided into three groups depending on their behaviour. Si, K, Na, Mg, Ca, Sr, Ba and V are mobilized and removed from weathered products. Fe, Al. Ti, Zr, Hf, Zn, Cu, Sc, Co and Ni are immobile. REE, Y, and to a lesser extent Cr, are mobile and redistributed within the profile without a net loss of these elements from the profile. Large positive Ce anomalies are developed in oxidized weathered products by preferential leaching of the other REE's. Negative Ce anomalies and REE enrichment is a feature of less altered dolerite.  相似文献   

Information infrastructure for Australia’s Integrated Marine Observing System     

Marton G. Hidas  Roger Proctor  Natalia Atkins  Julian Atkinson  Laurent Besnard  Peter Blain  Philip Bohm  Jon Burgess  Kim Finney  Dan Fruehauf  Guillaume Galibert  Xavier Hoenner  Jacqui Hope  Craig Jones  Sebastien Mancini  Benedicte Pasquer  David Nahodil  Kate Reid  Katherine Tattersall 《Earth Science Informatics》2016,9(4):525-534

Australia’s Integrated Marine Observing System (IMOS, imos.org.au) is research infrastructure to establish an enduring observing program for Australian oceanic waters and shelf seas. The observations cover physical, biological, and chemical variables to address themes of multi-decadal ocean change, climate variability and weather extremes, boundary currents and inter-basin flows, continental shelf processes and ecosystem responses.IMOS observations are collected by national facilities based on various platform types and operated by partner institutions around the country. In this paper we describe the infrastructure and workflows developed to manage and distribute the data to the public. We highlight the existing standards and open-source software we have adopted, and the contributions we have made. To demonstrate the value of this infrastructure we provide some illustrations of use and uptake.All IMOS data are freely and openly available to the public via the Ocean Portal (https://imos.aodn.org.au). All IMOS-developed software is open-source and accessible at https://github.com/aodn.  相似文献   

Weighted merge context for clustering and quantizing spatial data with self-organizing neural networks     

Julian Hagenauer 《Journal of Geographical Systems》2016,18(1):1-15

This publication presents a generalization of merge context, named weighted merge context (WMC), which is particularly useful for clustering and quantizing spatial data with self-organizing neural networks. In contrast to merge context, WMC does not depend on a predefined (sequential) ordering of the data; distance is evaluated by recursively taking neighboring observations into account. For this purpose, WMC utilizes a weight matrix that describes the neighborhood relationships between observations. This property distinguishes WMC from existing approaches like contextual neural gas (NG) or the GeoSOM, which force spatially close observations to be represented by similar prototypes, but neglected the similarity of the observations’ neighborhoods. For practical studies, WMC is combined with the NG algorithm to obtain weighted merging NG (WMNG). The properties of WMNG and its usefulness for clustering and quantizing spatial data are investigated on two different case studies which utilize an simulated binary grid and a real-world continuous data set.  相似文献   

The two basic components of the interstellar neutral hydrogen and its relation with the galactic structure     

Ramon Julian Quiroga 《Astrophysics and Space Science》1975,35(1):67-80

The two basic components of the neutral hydrogen, cool dense clouds merged in a hotter tenuous medium, are studied using 21 cm absorption data of the Parkes Survey. The mean parameters obtained for the typical clouds next to the galactic plane are τ_p = 1.7, velocity half-width=3.3 km s^?1. Their temperatures areT _sc ≥40 K with a meanT _sc =63±12 K and the obtained hot gas density isn _HH=(0.15±0.05) atom cm^?3. Theoretical analysis following Giovanelli and Brown (1973) reveals that the pressure equilibrium condition (n _HH+2n _e )·T _SH≈n _HC·T _sc is compatible with the quoted values if it is assumed that the cosmic abundances in the interstellar medium are below the adopted normal solar abundance. This lack of heavy elements suggests accretion to grains which is consistent with the observed narrow concentration of the dark matter on the galactic layer (≤100 pc halfwidth). The same pressure condition leads to a mean cool cloud density ofn _HC～30 atom cm^?3 and a hot gas temperature ofT _SH～10 500 K. Comparison with data from Hii regions suggests that the cool clouds are somewhat denser and less extensive than such regions. An explanation for it is the expansion that the Hii regions went through in their origin. Comparison with 21 cm emission data shows that the cloud galactic layer is only about a quarter as thick as the hot gas layer. All the present results suggest that only such clouds can be spatially related with the typical I population associated with the spiral structure.  相似文献   

Ocean bottom seismograph     

T. J. G. Francis  I. T. Porter  R. D. Lane  P. J. Osborne  J. E. Pooley  P. K. Tomkins 《Marine Geophysical Researches》1975,2(3):195-213

The ocean bottom seismograph described in this paper has been developed primarily for recording earthquakes on the mid-oceanic ridges. The instrument is suitable for dropping onto the most rugged areas of the ocean floor. Acoustic tracking with the ship's precision echo sounder enables it to be located there relative to both the topography of the sea bed and the ship. The outputs of a 3-component seismometer and a hydrophone are recorded in FM form on a low-power magnetic tape recorder designed specifically for the instrument.  相似文献   

A four-component ecosystem model of biological activity in the Arabian Sea   总被引：1，自引：0，他引：1  

Julian P. McCreary  Jr  Kevin E. Kohler  Raleigh R. Hood  Donald B. Olson 《Progress in Oceanography》1996,37(3-4)

A coupled, physical-biological model is used to study the processes that determine the annual cycle of biological activity in the Arabian Sea. The physical model is a system with a surface mixed layer imbedded in the upper layer, and fluid is allowed to move between layers via entrainment, detrainment and mixing processes. The biological model consists of a set of advective-diffusive equations in each layer that determine the nitrogen concentrations in four compartments: nutrients, phytoplankton, zooplankton and detritus. Coupling is provided by the horizontal-velocity, layer-thickness, entrainment and detrainment fields from the physical solution. Surface forcing fields (such as wind stress and photosynthetically active radiation) are derived from monthly climatological data, and the source of nitrogen for the system is upward diffusion of nutrients from the deep ocean into the lower layer. Our main-run solution compares favorably with observed physical and biological fields; in particular, it is able to simulate all the prominent phytoplankton blooms visible in the CZCS data. Three bloom types develop in response to the physical processes of upwelling, detrainment and entrainment. Upwelling blooms are strong, long-lasting events that continue as long as the upwelling persists. They occur during the Southwest Monsoon off Somalia, Oman and India as a result of coastal alongshore winds, and at the mouth of the Gulf of Aden through Ekman pumping. Detrainment blooms are intense, short-lived events that develop when the mixed layer thins abruptly, thereby quickly increasing the depth-averaged light intensity available for phytoplankton growth. They occur during the fall in the central Arabian Sea, and during the spring throughout most of the basin. In contrast to the other bloom types, entrainment blooms are weak because entrainment steadily thickens the mixed layer, which in turn decreases the depth-averaged light intensity. There is an entrainment bloom in the central Arabian Sea during June in the solution, but it is not apparent in the CZCS data. Bloom dynamics are isolated in a suite of diagnostic calculations and test solutions. Some results from these analyses are the following. Entrainment is the primary nutrient source for the offshore bloom in the central Arabian Sea, but advection and recycling also contribute. The ultimate cause for the decay of the solution's spring (and fall) blooms is nutrient deprivation, but their rapid initial decay results from grazing and self shading. Zooplankton grazing is always an essential process, limiting phytoplankton concentrations during both bloom and oligotrophic periods. Detrital remineralization is also important: in a test solution without remineralization, nutrient levels drop markedly in every layer of the model and all blooms are severely weakened. Senescence, however, has little effect: in a test solution without senescence, its lack is almost completely compensated for by increased grazing. Finally, the model's detrainment blooms are too brief and intense in comparison to the CZCS data; this difference cannot be removed by altering biological parameters, which suggests that phytoplankton growth in the model is more sensitive to mixed-layer thickness than it is in the real ocean.  相似文献   

Time-resolved optical spectroscopy of AM Her X-ray sources     

M. Mouchet  S. F. Van Amerongen  J. M. Bonnet-Bidaud  J. P. Osborne 《Astrophysics and Space Science》1987,131(1-2):613-624

We present high-time resolution spectroscopy of two AM Her sources E1405-451 and E1013-477. For E1405-451, the Balmer emission lines profiles can be divided into a narrow component and a broad one. The amplitudes of the radial velocity curves of these components are respectively 265±30 km/s and 390±50 km/s. The orientation of the column determined from polarimetry is not compatible with the broad component being formed in the lowest parts of the column. Photometric and spectroscopic results on E1013-477 do not confirm the previous reported 103 min. period. Rapid variability (<1.5h) as well as long term modulation (>3.3h) is present in these data.Paper presented at the IAU Colloquium No. 93 on Cataclysmic Variables. Recent Multi-Frequency Observations and Theoretical Developments, held at Dr. Remeis-Sternwarte Bamberg, F.R.G., 16–19 June, 1986.  相似文献   

Resumption of mass accretion in RS Oph     

H. L. Worters  S. P. S. Eyres  G. E. Bromage  J. P. Osborne 《Monthly notices of the Royal Astronomical Society》2007,379(4):1557-1561

The latest outburst of the recurrent nova RS Oph occurred in 2006 February. Photometric data presented here show evidence of the resumption of optical flickering, indicating re-establishment of accretion by day 241 of the outburst. Magnitude variations of up to 0.32 mag in V band and 0.14 mag in B band on time-scales of 600–7000 s are detected. Over the two-week observational period, we also detect a 0.5 mag decline in the mean brightness, from   V ≈ 11.4  to 11.9, and record   B ≈ 12.9 mag  . Limits on the mass accretion rate of     are calculated, which span the range of accretion rates modelled for direct wind accretion and Roche lobe overflow mechanisms. The current accretion rates make it difficult for thermonuclear runaway models to explain the observed recurrence interval, and this implies average accretion rates are typically higher than seen immediately post-outburst.  相似文献   

The Swift gamma-ray burst GRB 050422     

A. P. Beardmore  K. L. Page  P. T. O'Brien  J. P. Osborne  S. Kobayashi  B. Zhang  D. N. Burrows  M. Capalbi  M. R. Goad  O. Godet  J. E. Hill  V. La Parola  F. Marshall  A. A. Wells 《Monthly notices of the Royal Astronomical Society》2007,374(4):1473-1478

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