Value of Information Introduced by a Resource Model Updating Framework

A primary concern of the mining industry is to meet production targets, which are required and defined by customers. Deviations from these targets, in terms of quality and quantity, highly affect the economical aspect. Recently, an efficient resource model updating framework concept has been proposed aiming for the improvement of raw material quality control and process efficiency in any type of mining operation. The concept integrates online sensor measurements, obtained during production, into the resource model. In this way, due to the spatial variability, quality attributes of the blocks that will be produced in the next days or weeks are being updated based on real-time measurements. The concept has been applied in a lignite field with the aim of identifying local impurities in a lignite seam and to improve the prediction of coal quality attributes in neighbouring blocks. This paper investigates the added value of using the resource model updating framework by using the value of information analysis. The expected benefit of additional information (integration of the online sensor measurements into the resource model) is compared to a case where there is no additional information integrated into the process. These benefits are evaluated based on the economic impact determined by applying the resource model updating framework in mine planning.

     

DMS and SO2 at Baring Head, New Zealand: Implications for the Yield of SO2 from DMS

Atmospheric dimethyl sulfide (DMS) and sulfur dioxide (SO₂) concentrations were measured at Baring Head, New Zealandduring February and March 2000. Anti-correlated DMS and SO₂ diurnalcycles, consistent with the photochemical production of SO₂ from DMS, were observed in clean southerly air off the ocean. The data is used to infer a yield of SO₂ from DMS oxidation. The estimated yields are highly dependent on assumptions about the DMS oxidation rate. Fitting the measured data in a photochemical box model using model-generated OH levels and the Hynes et al. (1986) DMS + OH rate constant suggests that theSO₂ yield is 50–100%, similar to current estimates for the tropical Pacific.However, the observed amplitude of the DMS diurnal cycle suggests that the oxidation rate is higher than that used by the model, and therefore, that theSO₂ yield is lower in the range of 20–40%.     

The global distribution of methane in the troposphere

Methane has been measured in air samples collected at approximately weekly intervals at 23 globally distributed sites in the NOAA/GMCC cooperative flask sampling network. Sites range in latitude from 90° S to 76° N, and at most of these we report 2 years of data beginning in early 1983. All measurements have been made by gas chromatography with a flame ionization detector at the NOAA/GMCC laboratory in Boulder, Colorado. All air samples have been referenced to a single secondary standard of methane-in-air, ensuring a high degree of internal consistency in the data. The precision of measurements is estimated from replicate determinations on each sample as 0.2%. The latitudinal distribution of methane and the seasonal variation of this distribution in the marine boundary layer has been defined in great detail, including a remarkable uniformity in background levels of methane in the Southern Hemisphere. We report for the first time the observation of a complete seasonal cycle of methane at the South Pole. A significant vertical gradient is observed between a sea level and a high altitude site in Hawaii. Globally averaged background concentrations in the marine boundary layer have been calculated for the 2 year-period May 1983–April 1985 inclusive, from which we find an average increase of 12.8 ppb per year, or 0.78% per year when referenced to the globally averaged concentration (1625 ppb) at the mid-point of this period. We present evidence that there has been a slowing down in the methane growth rate.Presented at the Conference on the Scientific Application of Baseline Observations of Atmospheric Composition (SABOAC), Aspendale, Australia, 7–9 November 1984.     

Geomagnetic secular variation from recent lake sediments,ancient fireplaces and historical measurements in southeastern Australia

Compilations of historical observations, archaeomagnetic data from ancient fireplaces and palaemagetic results from short cores of sediment from lakes in southeastern Australia, particularly Lake Keilambete, provide a detailed record of the geomagnetic secular variation during the last 3000 years. The independent sets of data are in good agreement if the radiocarbon time scale for the lacustrine record is about 450 years too old. The error is attributed to systematic incorporation of ancient carbon into the lake floor sediments, mainly through erosion of sediment on the crater walls at times of low water level. A significant lag between deposition and the acquisition of stable magnetic remanence is ruled out. Inclination has been abnormally steep during the last 500 years but remained fairly close to the axial dipole field value prior to that. During the last 1000 years the predominant sense of looping of the magnetic vector corresponds to westward drift of the nondipole field. Secular variations on a time scale of ～ 100 years can be resolved by the lacustrine record.     

Promoting planetary science

Mike Hapgood summarizes the RAS's position on planetary sciences in the UK, a subject that delivers world-class results, but needs focused support in order to continue to thrive.     

Ionospheric correction of space radar data

Radar is a critical tool for maintaining knowledge of the many objects in low Earth orbit and thus for maintaining confidence that societies around the world are secure against a variety of space-based threats. It is therefore important to raise awareness that LEO objects are embedded in the envelope of relatively dense plasma that co-rotates with the Earth (ionosphere-plasmasphere system) and thus accurate tracking must correct for the group delay and refraction caused by that system. This paper seeks to promote that awareness by reviewing those effects and high-lighting key issues: the need to customise correction to the altitude of the tracked object and prevailing space weather conditions, that ionospheric correction may be particularly important as an object approaches reentry. The paper outlines research approaches that should lead to better techniques for ionospheric correction and shows how these might be pursued in the context of the EURIPOS initiative.     

Energetic Charged Particles Above Thunderclouds

The French government has committed to launch the satellite TARANIS to study transient coupling processes between the Earth’s atmosphere and near-Earth space. The prime objective of TARANIS is to detect energetic charged particles and hard radiation emanating from thunderclouds. The British Nobel prize winner C.T.R. Wilson predicted lightning discharges from the top of thunderclouds into space almost a century ago. However, new experiments have only recently confirmed energetic discharge processes which transfer energy from the top of thunderclouds into the upper atmosphere and near-Earth space; they are now denoted as transient luminous events, terrestrial gamma-ray flashes and relativistic electron beams. This meeting report builds on the current state of scientific knowledge on the physics of plasmas in the laboratory and naturally occurring plasmas in the Earth’s atmosphere to propose areas of future research. The report specifically reflects presentations delivered by the members of a novel Franco-British collaboration during a meeting at the French Embassy in London held in November 2011. The scientific subjects of the report tackle ionization processes leading to electrical discharge processes, observations of transient luminous events, electromagnetic emissions, energetic charged particles and their impact on the Earth’s atmosphere. The importance of future research in this area for science and society, and towards spacecraft protection, is emphasized.     

Fertile and barren AlCr-spinel harzburgites from the upper mantle: Ion and electron probe analyses of trace elements in olivine and orthopyroxene: Relation to lherzolites

Ion and electron microprobe analyses of twenty-one CrAl-spinel harzburgite xenoliths from southern African kimberlites show two chemical groups. Orthopyroxenes from “fertile” harzburgites have higher CaO (mean of 11, 0.95 wt.%), Al₂O₃ (3.05 wt.%), Cr₂O₃ (0.85 wt.%) and Li (0.8 ppmw) than those from “barren” harzburgites (mean of 10, CaO 0.24 wt.%, Al₂O₃ 1.10 wt.%, Cr₂O₃ 0.35 wt.%, Li 0.3 ppmw). Olivines from all harzburgites have similar chemistry except that mean values of Li and Na are higher for barren than fertile harzburgites (Li 0.9 vs. 0.4 ppmw; Na₂O 16 vs. 7 ppmw). Orthopyroxenes from fertile harzburgites are chemically distinct from those in garne lherzolites from southern Africa and spinel lherzolites from southwest U.S.A., but orthopyroxenes from barren harzburgites are indistinguishable from those in many coarse garnet lherzolites.Chromium, Ca, Ni, Na and Li in coexisting olivines and orthopyroxenes from the above rock types show complex patterns, which for Ca, Cr and Ni can be related to pressure and temperature. Temperatures from an empirically calibrated thermometer based on Ni-Mg exchange between olivine and orthopyroxene, measured modes of harzburgites (fertile, mean of 10: ol 68, opx 31, spinel-silicate intergrowth <0.5; barren, mean of 8: ol 76, opx 23, spinel and spinel-silicate intergrowth 1), and high-pressure experimental studies suggest (a) that harzburgites are residues of partial melting, (b) that barren harzburgites were melted to a greater extent at a higher temperature (though probably at a similar depth) than fertile harzburgites, and (c) that incomplete reequilibration during retrograde metamorphism has led to development of complex inter- and intragranular textures, probably in the range ～700–900°C.