Plume mapping and isotopic characterisation of anthropogenic methane sources

Methane stable isotope analysis, coupled with mole fraction measurement, has been used to link isotopic signature to methane emissions from landfill sites, coal mines and gas leaks in the United Kingdom. A mobile Picarro G2301 CRDS (Cavity Ring-Down Spectroscopy) analyser was installed on a vehicle, together with an anemometer and GPS receiver, to measure atmospheric methane mole fractions and their relative location while driving at speeds up to 80 kph. In targeted areas, when the methane plume was intercepted, air samples were collected in Tedlar bags, for delta C-13-CH4 isotopic analysis by CF-GC-IRMS (Continuous Flow Gas Chromatography-Isotope Ratio Mass Spectrometry). This method provides high precision isotopic values, determining delta C-13-CH4 to +/- 0.05 per mil. The bulk signature of the methane plume into the atmosphere from the whole source area was obtained by Keeling plot analysis, and a delta C-13 -CH4 signature, with the relative uncertainty, allocated to each methane source investigated. Both landfill and natural gas emissions in SE England have tightly constrained isotopic signatures. The averaged delta C-13-CH4 for landfill sites is -58 +/- 3%o. The delta C-13-CH4 signature for gas leaks is also fairly constant around -36 +/- 2 parts per thousand, a value characteristic of homogenised North Sea supply. In contrast, signatures for coal mines in N. England and Wales fall in a range of -51.2 +/- 0.3 parts per thousand to 30.9 +/- 1.4 parts per thousand, but can be tightly constrained by region. The study demonstrates that CRDS-based mobile methane measurement coupled with off-line high precision isotopic analysis of plume samples is an efficient way of characterising methane sources. It shows that iiotopic measurements allow type identification, and possible location of previously unknown methane sources. In modelling studies this measurement provides an independent constraint to determine the contributions of different sources to the regional methane budget and in the verification of inventory source distribution. (C) 2015 Elsevier Ltd. All rights reserved

An early Anglo-Saxon bridle-fitting from South Leckaway, Forfar, Angus, Scotland

[FIRST PARAGRAPH] In February 2003 the Kinnettles Heritage Group made a quite unexpected find during field-walking at South Leckaway farm near Forfar, Angus (NGR NO 4379 4810): the most northerly example in Britain — by about 150 miles — of an Anglo- Saxon object decorated in Salin’s Style I. It lay isolated and face down on the surface. A follow-up field-walk at the end of the month confirmed, partly with the aid of a metal detector, that there were no readily apparent additional pieces of metalwork, associated structures or burial evidence. The find was reported under the Scottish Treasure Trove legislation, duly claimed and allocated in June 2003 to the Meffan Institute, Forfar (part of Angus Cultural Services)

A baseline lunar mine

A models lunar mining method is proposed that illustrates the problems to be expected in lunar mining and how they might be solved. While the method is quite feasible, it is, more importantly, a useful baseline system against which to test other, possible better, methods. Our study group proposed the slusher to stimulate discussion of how a lunar mining operation might be successfully accomplished. Critics of the slusher system were invited to propose better methods. The group noted that while nonterrestrial mining has been a vital part of past space manufacturing proposals, no one has proposed a lunar mining system in any real detail. The group considered it essential that the design of actual, workable, and specific lunar mining methods begin immediately. Based on an earlier proposal, the method is a three-drum slusher, also known as a cable-operated drag scraper. Its terrestrial application is quite limited, as it is relatively inefficient and inflexible. The method usually finds use in underwater mining from the shore and in moving small amounts of ore underground. When lunar mining scales up, the lunarized slusher will be replaced by more efficient, high-volume methods. Other aspects of lunar mining are discussed

Optimization of sulfur production in the Kittilä mine via Deswik software

Abstract. The Kittilä Mine is an underground mine in northern Finland where sulfur content of the ore often restricts gold production. In order to optimize gold production, sulfur content of the ore fed to the mill must remain below a certain limit as to not overload the autoclave process. An analytical look of the mining process was taken to ensure a solid understanding of the planning process for the mine’s particular mining method. Various sulfur prediction methods were analyzed and using statistical analysis it was determined that the Primary Block Model grade estimates were the most effective grades to use in the remainder of the research. Deswik, the software in use for the mine’s planning and production, was then examined and reviewed from a user’s standpoint. Several aspects of Deswik were tested in attempts to create improved production plans regarding the sulfur limits or improved NPV. Throughout the trials, plans which included improved short term results delayed important development through the mine and disrupted steady production through the long term schedule. Other issues were found through trials, including the tendency of the optimization algorithms to take advantage of broken links throughout the task-progression network. The various methods and the corresponding results were compared and the advantages and disadvantages of the Deswik system were assessed

The effects of short delay times on rock fragmentation in bench blasts

Optimized rock fragmentation is essential for minimizing downstream costs to mining operations. Photographic fragmentation analysis, vibration monitoring, and high-speed video all provide measurements of blast effectiveness and supply data that allows operations to modify blasts to achieve downstream goals. This study evaluates the effects of short hole-to-hole delay times on rock fragmentation. Photographic fragmentation analysis and various delay times were used on the same bench blast, the effects of timing on fragmentation were determined. This analysis provides a representative understanding of timing effects on fragmentation in the field, different from previous blast models which either negate the effects of timing or geology. Four test blasts were conducted at a granite quarry in Talbotton, GA. For each test blast, the bench was divided into three timing zones. This allowed for multiple delay times to be evaluated in each shot and it provided visual comparison of the variable face movement and throw. Hole-to-hole delay times included 0 ms, 1 ms, 4 ms, 10ms, 16 ms, and 25 ms across the various zones. The 16 ms and 25 ms times were the baseline times against which the short delay results were evaluated. The 0 ms and 1 ms times included stress wave collision regions, and the 10 ms time was based on the speed of sound in the rock and burden distance. Each blast was monitored using high-speed video and seismographs. Dyno Consult provided additional seismograph and video monitoring, along with bore track and 3D laser profile data. Multiple photographs were taken of each of the zones for WipFrag analysis. Based on the fragmentation analysis the 25 ms and 10 ms delay times resulted in the smallest rock fragmentation, while the 1 ms delay gave the coarsest fragmentation --Abstract, page iii