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By Christopher Jon Preston

This paper describes a type of ammonium nitrate (AN) produced in a patented experimental atomization/aerodynamic process. This AN exhibits outstanding properties for use as a main ingredient to a new family of AN-based commercial explosives. Micro-particle ammonium nitrate (MP-AN) is produced by atomizing either an 83% or 85% AN solution which has been doped with a two component surfactant NSol 1000 (NSol). NSol imparts some water-resistance as well as provides a means of increasing density and bulk strength. Increased detonation velocities, well in the range of emulsion explosives, can be achieved. The maximum manufacturing temperature is less than 100°C. The methodology has the potential of being environmentally friendly since any effluent can be recycled back into a make-up tank to be re-used by the closed loop method. The process has a small footprint.

Jan 1, 2015

By Kennedy G. L, Evans D. G

The development of the carbonization of brown coal briquettes to produce a hard char suitable for use in place of imported hard coke has continued in Victoria, and an experimental carbonization plant has recently been commissioned at Morwell by the Gas and Fuel Corpora.tion to assess the prospects for the commercial production and marketing of hard char in Victoria. The char offers advantages in its very low ash content and its uniform lump size, while the indications are that it could be marketed at a price competitive with that of imported hard coke. The hard char is unique amongst metallurgical fuels in combining a high reactivity with high physical strength, and research by the University of Melbourne into its utilization in foundry cupolas for melting iron has shown how modifications could be made to take advantage of these properties. An 18 inch experimental cupola has been built to test in practice the predictions made from this fundamental research.INTRODUCTIONSteady development has continued in Victoria from the promising laboratory researches at the University of Melbourne which were reported to the 1955 Annual Conference of The Institute (Worner, 1956). This work had shown that a hard lump char could be produced by the high temperature carbonization of standard industrial briquettes by careful control of the heating conditions, and that the special briquetting techniques adopted in Germany were unnecessary with Yallourn brown coal. Continuation of this research has led to the refinement of carbonization techniques and has increased the strength of the char until it has equalled that of conventional metallurgical cokes.

Jan 1, 1960

By J. D. Law

The presence of long-lived radionuclides presents a challenge to the management of radioactive wastes. Separation of the radionuclides from the waste solutions has the potential of significantly decreasing the costs associated with the immobilization and disposal of the waste by minimizing waste volumes. Several solvent extraction processes have been developed at the Idaho National Engineering and Environmental Laboratory for the separation of transuranic elements (TRUs), 90 Sr, and/or 137 Cs from acidic radioactive waste solutions. The TRUEX and POR processes for the separation of TRUs, the SREX process for the separation of 90Sr, the cobalt dicarbollide process for the separation of 137Cs and and a universal solvent extraction process for the simultaneous separation of TRUs, 90Sr, and 137Cs have all been developed in centrifugal contactors using actual liquid radioactive waste solutions and simulated dissolved calcine waste solution. In addition, the behavior of metals with each of the solvent extraction processes was evaluated. This article summarizes the most recent results of the each of the flowsheet demonstrations and provides Information on the centrifugal contactor equipment used for the testing.

Jan 1, 1999

By Wils L. Cooley

Two major grounding topics are covered: mine ground systems and ground-check monitors. Performance characteristics of ground-check monitors for high-voltage surface mine distribution cables and low-voltage underground mine trailing cables are evaluated. Over 20 commercially available monitors are studied to determine their utility. Several monitoring concepts are incorporated into an unusual monitor design, the prototype of which is described in detail. A comparative study of the effectiveness of several alternate methods of grounding surface mine equipment supports the system currently proposed by MSHA. An instrument design to measure earth voltage gradients is described, as well as an instrument design for measuring the effectiveness of dc haulage current return systems. An extreme analysis is made of techniques for measuring earth resistivity and resistance of safety ground beds. Electrolytic corrosion studies of earth electrodes are reported extensively also.

Jan 1, 1979

By S. H. Ash

NO MORE important question has come before the coal-mining industry in many places, especially in the anthracite region of Pennsylvania, than prevention of stream pollution by mine drainage. Available information on acid mine drainage in the anthracite region of Pennsylvania indicates that a pollution problem must be solved in any program of anthracite mine drainage. The major problem concerns satisfactory disposal of the daily average mine-water discharge of 327,000 gallons per minute (g. p. m.), or 472 million gallons per day (g. p. d.), containing a free-acid load of 431 tons or a total acid load of 934 tons a clay as H2S04. This report indicates the scope of the problem and gives some suggestions concerning its solution.

Jan 1, 1951

By M D. Hannington

On the southern flank ofLihir Island, a group of three volcanic cones were discovered at water depths from 1000 - 1500 m. The volcanoes are located in a narrow zone of recent seismic activity and elevated heat flow (up to 100 mW/m2). The recovered rocks consist of fresh alkali-olivine basalts, clinopyroxene-rich basalts, and porphyritic phlogopite basalts. One of the volcanoes has a recently erupted ejecta blanket (recovery of warm ash!), containing a suite of abundant mafic to ultramafic xenoliths. These xenoliths appear to represent a unique cross-section of subduction-modified mantle material sampled by volatile-rich primary fore-arc magma during its ascent to the seafloor. The most spectacular finding was the discovery of an active hydrothermal system with associated vent fauna and mineralization at Edison Seamount, and the recovery of unusually gold-rich (up to 43 ppm Au) hydrothermal precipitates in 1050 m water depth at the top of Conical Seamount, only 25 km south of the world-class epithermal Ladolam gold deposit on Lihir. The discovery of submarine hydrothermal vents associated with highly alkaline, quartz-undersaturated fore-arc volcanics represents a significant departure from similar hydrothermal systems on the mid-ocean ridges and in back-arc basins. The high gold grades in hydrothermal precipitates at Conical Seamount may indicate the first documented example of a shallow-marine epithermal system analogous to those known on land, and has important implications' for the gold potential of submarine arc environments.

Jan 1, 1995

By Y. Özçelik

Rocks show a variety of engineering and physical properties that affect typical quarry operation such as diamond wire cutting in the marble quarry. The physical and mechanical properties of rocks depend on their mineralogical and petrographical characteristics. The purpose of this study is to investigate the effects of mineralogical and petrographical properties of a rock, such as grain size and mineral content, and how these affect the wearing of diamond bead and cutting rate in a diamond wire cutting operation in a marble quarry. Statistical analysis is used to carry out the study. Three different rock types were examined, namely, hard rock (andesite) and softer rocks like limestone and marble. The study revealed that the mineralogical and petrographical properties of the rocks, such as percentage of quartz, biotite, plagioclase, matrix minerals, and opaque minerals, are important. In addition, the grain size of quartz and plagioclase in andesitic rocks and calcite grain size for carbonate rocks significantly influenced the wear rate and cutting rate in diamond wire cutting operations.

Jan 1, 2005

The recent paper by Bain (1981) contains an unfortunate, and potentially misleading typographic error. On page 9, second paragraph, Bain states that, "some samples of drill core from the (Candlow) Formation ... contain up to 90 ppm gold and 2 000 ppm arsenic". The gold value should read 90 ppb. In fact, in the original version of the paper (Bain, 1980), the gold value quoted was actually 60 ppb.Bain also refers briefly to some geochemical data which is attributed to me, and which I feel require some clarification.In addition, the paper contains some factual errors relating to the occurrence of carbonate and potential host rocks to Carlin-type gold deposits in the Candlow Formation.

Jan 1, 1981

By R. Scott

This article describes and evaluates the establishment of Kuyasa Mining including the search for a suitable deposit, the ongoing lack of finance, and market constraints. Despite the dramatic initial growth and success of their Ikhwezi Colliery near Delmas, Mpumalanga, Kuyasa?s experiences offer some sobering arguments for significant changes to mineral rights ownership, the attitude of financial institutions and government policy if South Africa is to have a dynamic and successful junior and small-scale mining sector.

Jan 1, 1998

By J. Krzyzanowska

Paper written on project work carried out in partial fulfilment of Bachelor of Engineering-Mining Venetia Mine, an open-pit diamond mining operation in the Limpopo Province of South Africa, currently has a mixed haul truck fleet consisting of Caterpillar 785B and C; 789C; modified 793D and 793D. Even in an ideal situation these trucks have different cycle times, which causes queuing at the loading area and their different speeds cause bunching on the ramps, leading to higher overall cycle times and lower productivity. This problem was identified but the root causes of the problem were not investigated and quantified. A time and motion study on the haul trucks was thus undertaken to measure actual cycle times and compare them to ideal cycle times as well as to observe any reasons for deviations. Ideal cycle times are partly evaluated on the basis of simulation and partly from production optimization expert input. Several areas that affect production were identified and these include: haul road conditions, the control room, dispatching programme and dispatching data management, as well as truck-shovel matching. The investigation was important in establishing control parameters for haul fleet operation since time spent queuing is production time lost, which defers waste tonnes to later in the life of mine, thus decreasing the tempo at which kimberlite is exposed.

Jan 1, 2007

By T Sprague, D Pateman

"The Gosowong Gold Project is owned and operated by PT Nusa Halmahera Minerals (PT NHM), an Indonesian company 75 per cent owned by Newcrest. It is located on Halmahera Island, in the North Maluku Province of the Republic of Indonesia, approximately 2450 km north-east of the national capital, Jakarta (Newcrest, 2017).Kencana is one of two underground gold and silver mines at the Gosowong Operation where ground conditions vary from competent to very poor. Development headings occurring in poor rock mass conditions require high capacity ground support including long tendon cable bolts. Manual installation of cable bolts in these development headings has been a time consuming process due to borehole collapse, blockages requiring subsequent re-drilling and a minimum eight hour grout curing time interval. The installation of cable bolts including the setting, plating and tensioning can impact the critical path for development heading advance resulting in development cycle delays.A review was conducted by PT NHM on current industry practices for alternatives to manual cable bolting. PT NHM subsequently approached Minova to assist with the development and trialling of self drilling anchors (SDAs) installed using jumbos with a rapid setting pumpable resin, CARBOTHIXTM. A series of system development trials were conducted and a reliable bolting system was developed utilising the existing jumbo drilling fleet with minimal required modifications.The system developed was a ‘one pass’ bolting process to install and grout SDAs using a two component resin with a remote, mechanised system. Improvements achieved from the system include: eliminating hole closure issues and more immediate support in poor rock mass effectively reducing personnel exposure to poor ground conditions by removing the requirement to access the drive backs reducing grout set time with full installation times for 6 m SDAs averaging 25 min.The resin grouting system has now been successfully implemented to effectively manage areas of poor ground conditions and to accelerate advance rates in high priority headings.CITATION:Pateman, D and Sprague, T, 2017. Development and implementation of a long tendon bolting system utilising resin grouting technology, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 79–84 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 16, 2017

By H. Utsunomiya, J. Su, K. S. Tamimi, S. Yue, M. Sanjari, L. Kestens, Hara, A. S. Kabir, R. Petrov

Manufacturing of thin sheet is difficult in industries. Some approaches, such as small-draft multi-pass rolling, intermediate annealing, isothermal rolling and high-speed rolling were proposed to overcome the deformability. In this study, different rolling speeds from 15 to 1000 m/min were employed to twin rolled cast AZ31B magnesium alloy to different reductions. The results show thatAZ31B sheets rolled at 15 m/min and 100 °C has fractured for reductions of more than 30% per pass. However, by increasing the rolling speed to 1000 m/min the rollability was improved significantly and the material can be rolled to reductions of more than 70% per pass. The high speed and heavily deformed materials are fully recrystallized even at 100 °C.

Jan 1, 2014

By Keith Bowers, Frank Mimnagh, Eddie Woods

The CTRL London Tunnels The Channel Tunnel Rail Link (CTRL) London Tunnels comprise 36km of internal diameter bores that were driven by Earth Pressure Balance (EPB) Tunnel Boring Machines (TBMs). The tunnels were constructed between the autumn of 2002 and the spring of 2004. The permanent works also included the 1.1 km long station box at Stratford, five ventilation shafts of depths between 30 and 54 m, 29 cross passages and various large diameter sprayed concrete lined connecting tunnels. The tunnels were driven under densely populated areas of north and east London, as depicted in Figures 1 to 4. Under the parliamentary CTRL Act the project had obligations to make

Jan 1, 2005

The analysis of in-mine grounding systems began with an extensive literature search which is still in progress. About a dozen articles have been found which deal directly with grounding problems on low voltage power systems or mine power systems. These systems have special grounding problems because normal load currents can be nearly as large as many types of fault currents. Information has been collected on the influence of cable spacing) conduit geometry, location of nearby conducting structures, etc., on the magnitude and path of fault current. Many other articles have been found which are less directly related to mine ground system analysis. The in-mine ground system analysis team has also inspected portions of two mine power systems to become familiar with the practices used in grounding. One electrical engineer and several other mine personnel have been interviewed concerning mine power system grounding practice. Already several aspects of the mine grounding system have been marked as requiring special attention.

Jan 1, 1975

By John D. Campbell

"IS YOUR MANAGEMENT CONTROLLOOP FUNCTIONINGMineral processors make use of hundreds of control circuits in their mills, process plants, smelters and refineries, to optimize throughput and recovery and minimize cost. This afternoon, I would like to discuss what is probably the weakest circuit in any mineral processing operation - the management control loop.In their recent book ""The Winning Streak"", Goldsmith and Clutter describe extensive research on unsuccessful companies. They conclude that ineffective control, which does not immediately identify the problems, is one of the main failings of unsuccessful companies.We will look at the three key components of control which, from the manager's point of view, ensure that the loop is complete. These three are:• measuring what's happening,• assessing its significance, Rnd• altering performance.If we compare management control to process control as shown in this first figure, ""We see that parameter sensing by the analyzer in a process circuit is analogous to performance monitoring by management in a responsibility centre. The analyzer senses temperature, pressure, flow, weight or some surrogate indicator such as colour to indicate ion concentration. For manage1nent, the performance to rnonitor is dependent upon the objectives of the responsibility centre, and the key factors which affect these objectives."

Jan 1, 1985

By Sydney H. Ball

It is a peculiar anomaly that while the world uses the term "rich as a gold mine" as the superlative figure of speech descriptive of wealth, the shares of gold mines are not as popular investments in America as certain of them should be. One of the most able of Manhattan's bankers is a director in an investment trust with a portfolio the value of which has gone the way of other such portfolios. Luckily a couple of years ago a few hundred shares of Homestake were purchased, and since then the trust has not only received therefrom satisfactory dividends but has benefitted from a large appreciation in their value. At each directors' meeting, however, the banker in question, Cato-like, suggests the sale of these shares, gold shares being, in his opinion, too speculative to be included in the portfolio of any trust. A short time ago the financial pages of one of our great metropolitan papers featured an article listing the corporations still paying dividends at the 1929 rate. Gold-mining shares were, the article stated, excluded, although in reality every gold mine on the New York Stock Exchange paid higher dividends in 1932 than in 1929. This 'Alice in Wonderland' treatment of the gold-mining shares is admittedly a bit confusing to those of us who believe that the shares of certain gold-mining companies have a rightful place in any well diversified portfolio. It should, however, here be recorded that whereas, fifty years ago, in America, gold-mining shares were considered by the public as instruments of nefarious gambling, now shares of the better gold mines are sought by astute investors. In England for well over a generation their value as sound investments has been widely recognized.

Jan 1, 1933

By F F. Pitard, K J. Ehrig

The Olympic Dam iron-oxide copper-gold (IOCG) uranium-silver deposit is second in size only to Norilsk, the gigantic metalliferous deposit. Olympic Dam is the largest publicly declared uranium, fifth largest copper and third largest gold resource. The deposit is typified by texturally destructive brecciation and intense iron metasomatism of the Roxby Downs Granite, bedded clastic facies rocks and mafic-ultramafic dykes. The deposit contains over 100 minerals. Copper mineralisation consists of chalcopyrite, bornite and chalcocite. Uraninite, coffinite and brannerite are the dominant uranium-bearing minerals. Gold mineralisation consists of electrum, tellurides and Au-Cu alloys. Hessite is the major silver-bearing mineral. The economic minerals are disseminated throughout the breccia matrix where the average grain sizes of the Cu-sulfide, uranium, gold and silver minerals are ~50, 20, <5, <5 microns, respectively.A significant number of sampling theory-based test programs have been completed since the mid-1990s to establish sampling nomographs, select appropriate sampling (ie split versus chip and interval lengths) and sample preparation protocols, quantify the errors associated with each subsampling stage, determine the practical uncertainty limits of Olympic Dam matrix-matched standards, and identify improvement opportunities related to the ongoing assaying quality assurance / quality control (QA/QC) program. Invaluable knowledge and unexpected insights gained from sampling studies at Olympic Dam have helped to improve our understanding of the distribution of economic and deleterious elements within the Olympic Dam deposit.CITATION:Ehrig, K J and Pitard, F F, 2017. Underground bulk sampling, uniform conditioning and conditional simulation – unrealistic expectations?, in Proceedings Eighth World Conference on Sampling and Blending , pp 21–28 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By Glenn E. Craig

The practical and effective pulp distributor here presented is believed to be of a completely new and innovative design. It was developed at the San Nicolas Plant of the Marcona Mining Company in Peru, where it has been thoroughly plant tested using iron ore slurries of a particularly abrasive nature. It has proven to be superior to the apparatus originally installed, or to any observed in operation elsewhere. In plant practice the capacity and efficiency of many process units such as screens, magnetic separators, and jigs are strongly affected by the loading pattern, and for better results the flow of pulp must be proportioned across the receiving lip in equal quantities per unit width. The distributors originally installed on the drum magnetic separators in San Nicolas proved to be unsatisfactory, and several trial modifications failed to show any improvement. As is usually the case, feed rates were being steadily increased, and appreciable losses to tailings resulted. A check of the distributors on the market discloses no reasonable substitute, so efforts were directed toward devising an entirely new type. Required was a positive type of action which would guarantee that the pulp flow be spread equally along the length of the drum. Discussion As indicated, the motivation for development was simple necessity. The plant in San Nicolas crushes, grinds, and concentrates magnetic iron ores of a particularly abrasive nature, and depends largely on magnetic separation to obtain a marketable product. Feed to the numerous drum magnetic cobbers and finishers varies from rod mill discharge at a nominal minus ten mesh to a ball mill fine grind of seventy percent minus three hundred and twenty-five mesh. Operational factors affecting the magnetic separators were well controlled,

Jan 1, 1971

Currently an Australian Standard for tunnel fire safety is being developed for road and rail tunnels. Other local guidance relating to tunnel fire safety that has recently become available includes publications by both the Roads and Traffic Authority and RailCorp of New South Wales. Internationally, the World Road Congress has completed its 2004 - 2007 cycle, which has resulted in a number of publications. International developments in rail guidance include a new European Standard regarding fire safety in railway tunnels that will come into effect in July 2008. In addition, the National Fire Protection Association committee NFPA 130 are in the process of revising their standard for fixed guideway transit and passenger rail systems, which is due for publication in late 2009. This paper outlines the status of these and other recently published relevant local and international fire safety guidelines and their implications for tunnel projects in Australia.

Jan 1, 2008

By W. H. Schiffbauer

The U. S. Bureau of Mines has been investigating methods and technology that, when applied to existing continuous coal mining machines, may improve production and safety. Toward those goals, a microcomputer network has been designed that provides automated control and monitoring of all mining machine systems using a single twisted pair cable (two conductor stranded wire twisted together to provide a level of noise rejection). The network also provides -connections for intelligent sensors and systems for navigation and diagnostics. The flexibility of the network is demonstrated in that features can be added and removed without redesigning the whole system. A general description of the network's integration to a Joy' 16CM, Joy 14CM, Jeffrey 102, and a custom built auger machine is provided. The microcomputer networks for the Joy 16CM and the Jeffrey 102 have been installed onboard the mining machines and have been extensively tested at the Bureau of Mines test facility. The Jeffrey 102 system has also been tested in an actual highwall coal seam. Both systems have performed satisfactorily. The microcomputer networks for the Joy 14CM and the Auger Miner have been tested and await installation on the respective machines.

Jan 1, 1990