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By Larry Schneider

I n the simplest application of a shock tube initiation system, the tubing acts as a “relay line” which passes a detonation signal from borehole to borehole. When the signal arrives at each borehole, it causes the detonator attached to it to fire. Such a single path constitutes a progressive series where each unit must function properly in order to activate the following units. Any application error, malfunction, or mistake in connecting any surface unit will stop the progression of the detonation signal through the system and result in a “cutoff” or misfire of the following charges.

Jan 1, 1995

Minerals processing operations use a significant quantity of fossil carbon to provide energy and as reductant. Greenhouse gas emissions from the use of this fossil carbon contribute to the global increase in anthropogenic CO2 emissions to the atmosphere. In the spirit of fostering thinking about a step change in this situation, this paper explores opportunities for the use of sustainable carbon from biomass sources in a range of mineral processing operations. The exploration shows that many common processes are contenders for fossil carbon replacement and that feasible scientific research by minerals processing technologists would add to deeper understanding of the potential for a sustainable bio-carbon based industry. It is also shown that there are many dilemmas on the social, environmental and economic fronts to be solved before a biomass based industry could become a reality.

Jan 1, 2004

Previous methods for the assessment of the explosive potential of gas mixtures have required the plotting of apeexplosibility diagram. These became cumbersome if a large -number of assessments of various sampling locations over a period of time wererequired. This may make the approach of a dangerous situation more difficult to predict. With the aid of a programmable calculator, a new method for the rapid assessment of the explosibility of coal mine sample gases has been developed. This method does not require that an explosibility diagram be drawn to indicate the explosive status of a gas mixture. Simple Cartesian co-ordinates representing the explosive potential of,mixtures are obtained, which may readily be plotted to show changes with time.

Jan 1, 1981

By Mona M. Fawzy, Ahmed A. Eliwa, Ebrahim A. Gawad, Ahmed H. Orabi, Amal E. Mubark

The growing demand for rare earth elements (REEs) has led to numerous recent studies to recover these elements from various bearing ores and wastes. Therefore, the recovery of REEs from Ras Baroud polymetallic concentrate has been investigated in the current study. Physical beneficiation for the Ras Baroud pegmatite sample was carried out, yielding a concentrate for euxenite (Y), fergusonite (Y), xenotime (Y), monazite (Ce), allanite, thorite, uranothorite and Hf-zircon, which resulted in raising the concentrations of REEs, Th, Zr, U and Ti in the sample. Fusion digestion processes with sodium hydroxide were studied using the conceived predictive diagonal (CPD) technique. The three experimental digestion groups proved the dissolution of 99.9, 95.6, 99.9, 52.5 and 0.47 percent for REEs, Th, U, Ti and Zr, respectively, under fusion conditions of 723 K, 120 min, 1/1.5 ore-to-alkali ratio, and smaller than 100-μm particle sizes. Fusion kinetics, isotherms and thermodynamics were investigated using several suggested models, namely, pseudo reversible first order, uptake general model and shrinking core model, which matched well with the experimental digestion results. Selective recovery of actinide content from the REE content of the digested concentrate chloride solutions was accomplished using solvent extraction with di-2-ethyl hexyl phosphoric acid. About 99.9, 99.9 and 4.2 percent extraction efficiencies for Th, U and REEs were realized, respectively, using 0.3 mol/L solvent concentration in kerosene as a diluent, 1/2 organic-to-aqueous ratio, aqueous pH of 0.2 and contact time of 15 min. Thorium and uranium ions were stripped with 2.5 mol/L sulfuric acid solution with 94 and 98 percent stripping efficiency, respectively. A highly purified REE precipitate was obtained from the raffinate solutions. Zircon mineralization tailings were obtained as a byproduct through the alkaline digestion process.

Oct 1, 2024

By P J. Bangerter, G D. Corder

With the societal desire and drive towards low carbon energy sources, there is a growing awareness of the important role that minerals and metals will play with renewable energy technologies. Copper is an essential metal for technologies that generate energy from renewable sources, in particular for wind and solar photovoltaic energy systems. A recent report (Arrobas et al., 2017) estimated that the median increase in copper demand through to 2050 for wind technologies and for solar photovoltaics would need to be 250% and 300% respectively to meet the goal of a 2°C global temperature increase scenario compared with a 6°C global increase, which is largely an extension of current trends (IEA, 2018). The aim of this extended abstract is to demonstrate with the necessary increase in copper production for renewable energy technologies that sound sustainability performance across the global copper value chain is to the benefit of government, society and industry.CITATION:Corder, G D and Bangerter, P J, 2018. Balancing the benefits and impacts of future copper demand – climate change and arsenic, in Proceedings Life-of-Mine 2018, pp 17–19 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By R. W. Smith

The Bureau of Mines has been engaged in a systematic evaluation of the thermodynamic properties of combustion gases. These studies were designed to provide basic thermodynamic information of high accuracy, facilitating the theoretical study of flame and combustion phenomena.4 This report is the fifth of a series5/ presenting results of the study for particular fuel-oxidant systems. These calculations have as their objective the constant pressure flame temperature of acetylene-air for a range of pressures.

Jan 1, 1954

By Carl-Henrik Knudsen, Rolf Tore Arnesen, Eigil R. Iversen

Recovery of iron and copper from acid mine drainage was studied in pilot scale at a continuous treatment plant at the mine site of the King's mine in Roeros, Norway. The average load on the plant was 1 m3/h. The process tested in this project is a three-step process consisting of: 1) Fe(OH)3 precipitation at pH 3.5, dewatering of iron sludge and transport to ferric chloride plant; 2) after filtration precipitation of residual metals at pH 9, concentration of metal sludge by flotation; 3) extraction of metals from the sludge with sulphuric acid followed by recovery of copper by electrolysis. The copper could be used for local production of different crafts, but this condition needs a further evaluation. The process economy at a full scale plant is evaluated.

Jan 1, 2000

By C. M. Mason

Bureau of Mines studies were made on the sensitivity of several ammonium nitrate-fuel oil (AN-FO) mixtures to bullet impact. The experimental work was done with one military rifle and two high-velocity sporting rifles with a variety of ammunition. For the three rifles used, the order of efficiency in initiating detonation in AN-FO mixtures was 220 Swift >300 Weatherby Magnum >30-&apos;06. The velocity of the bullet was found to be a decisive factor in the initiation. The sensitivity of various materials studied increased as follows: Clay-coated prills with 4 percent oil <fresh surfactant-coated prills with 4 or 6 percent oil <surfactant-coated prills with 4 or 6 percent oil and aged 270 days <crushed prills with 6 percent oil <very low-density, surfactant-coated prills (micronized), with 4 percent oil.

Jan 1, 1963

By James S. Graham

Marine design and construction methods are presented on the caisson foundations for the tower piers at the Brooklyn, Ben Franklin, Delaware Memorial 1st, Tappan Zee, Walt Whitman, Throgs Neck, Verrazano Narrows, Delaware Memorial 2nd, and Newport Bridges. All of the bridges are founded on caissons, bearing on bedrock, soil, or piling. Caissons at the Tappan Zee Bridge are partially supported by piling and partially by buoyant forces. General subsurface conditions for each are provided. The purpose of this paper is inform engineers how bridge foundations using caissons were built over major waterways in the Northeastern USA in the past, anticipating a surge of new bridge construction in the near future.

Jan 1, 2013

By Donald G. Oss

The need for instrumentation and automatic control of the various parameters in the heavy media process of iron ore beneficiation has been apparent for some time. Continued demands for higher grade, competitive products from the Mesabi Range have made it necessary to increase the efficiency of the process in every possible way. A brief review of a typical heavy media flow scheme, as illustrated in. Figure l, might be in order for those not intimately associated with this process of iron ore beneficiation.

Jan 1, 1962

By W. J. Cherones

This paper describes the history of the development and application of the electric mining shovel in open-pit mining, dea1ing particularly with far-reaching advancements in three primary areas: metallurgy, mechanical design and electrical systems. Hoist drives and crowd drives, including the Magnetorque and Electrotorque systems, and the integral propel drive are given close attention.

Jan 1, 1972

By F. Awotwe-Appiah, P. Koshy, A. Y. Fosu, J. Dankwah, J. R. Dankwah

Ghana currently exports its bauxite raw without any value addition. Gradual depletion of high grade bauxite (with high alumina content) and the emergence of low grade bauxite (with high iron oxide content) calls for novel and inexpensive ways to recover alumina from these low grade ores. Bauxite users have indicated their willingness to pay 10% to 50% higher for a corresponding reduction in impurities by a similar amount. This project therefore investigates the carbothermal upgrading of the Ghana Awaso bauxite using waste polypropylene as reductant in a locally designed gas-fired furnace. Composite pellets of low grade bauxite sample (assaying 45% Al2O3) containing pulverised waste polypropylene were formed, oven dried, placed in fireclay crucible and fired for 30 minutes. The magnetic fraction after reduction was separated by a Low Intensity Magnet and weighed. It was observed that up to 97% of the iron oxides (occurring as hematite and goethite) could be separated into the magnetic fraction as magnetite leaving a nonmagnetic fraction with over 98% Al2O3 as opposed to the 45% Al2O3 in the as-received bauxite sample. This research direction provides yet another simple but effective way for simultaneously upgrading low grade bauxite and recycling waste polypropylene, whilst at the same time decreasing the amount of waste material generated as red mud after the Bayer process.

Jan 1, 2015

By James W. Ballard

The facts are generally accepted that an atmosphere containing large quantities of any dust is objectionable to breathe and that some dusts are more dangerous than others. Therefore, knowledge of the composition of dusts is important in evaluating the hazard entailed on exposure. At present, free silica, of which quartz is the most abundant form, is considered one of the most significant dusts, from the standpoint of pneumoconiosis, and one State5/ has established permissible limits of air dustiness on the basis of the free-silica content of rock. The amount of free silica in materials used for rock dusting also has been limited.6/ Determination of free silica or quartz, therefore, is important.

Jan 1, 1940

By Douglas J. Lootens

Geologic mapping was undertaken in the Sierrita Mountains as part of a Doctoral program at the University of Arizona, Tucson. During the study, approximately 35 square miles was mapped in detail, with particular attention given to specific areas of great or significant structural complexity and their relation to mineralization in the vicinity. A combination, of field studies and photogeologic interpretation was used in order to define regional and local structural controls for disseminated copper-molybdenum mineralization in and adjacent to the study area. Gratitude is expressed to the faculty of the University of Arizona, Department of Geology for their assistance in this work and to Bear Creek Mining Company for making numerous reports and drill cores available for study.

Jan 1, 1965

By Shadia J. Ikhmayies

"Cadmium sulfide thin films were prepared on glass substrates by the spray pyrolysis technique at a substrate temperature of 490°C. Some of the films were etched by HC1 in distilled water, others were heat treated in nitrogen atmosphere, and another set of films was first etched by HC1 and then annealed. Room temperature impedance spectroscopy measurements on the films were performed using coplanar geometry in the dark and in room light in the frequency range 20 Hz to 1 MHz. The experimental data were represented by complex plane diagrams and showed one well-defined semicircle in the high frequency region. Hence the equivalent circuit that models the CdS: In thin films was found to be a single RC circuit, which indicates the bulk conduction through the grains. The influence of treatments on the electrical properties was investigated.IntroductionCadmium sulfide (CdS) is a brilliant II—VI semiconductor material with a direct band gap of 2.42 eV at room temperature. It has many outstanding physical and chemical properties, which have promising applications in multiple technical fields including photochemical catalysis, gas sensor, detectors for laser and infrared, solar cells, nonlinear optical materials, various luminescence devices, optoelectronic devices and so on [1]. There are different methods to prepare undoped and doped CdS films, such as rf sputtering [2] chemical bath deposition (CBD) [3], pulsed laser deposition (PLD) [4], and spray pyrolysis (SP) [5-11]. Of these methods, spray pyrolysis represents the less expensive option, and can produce large area high-quality low cost thin films [12]."

Jan 1, 2012

By S Gossmann, J Barlow, S Denner

"Unconventional gas resources, including coal seam gas (CSG) reservoirs, can be located above and below aquifers that provide groundwater for agricultural, industrial, urban and other uses. Development of these resources may, therefore, lead to potential impacts on groundwater supply.Management of reservoir/aquifer interconnections necessitates a program of focused data acquisition. For example, groundwater transfer from shallow aquifers to underlying CSG reservoirs may occur where CSG-containing units subcrop beneath shallow aquifers, possibly at significant distances from operating wells.Arrow Energy is undertaking studies of connectivity between aquifers including an investigation in collaboration with the Queensland Office of Groundwater Impact Assessment to evaluate connectivity between the Condamine Alluvium (CA) and CSG-containing Walloon Coal Measures (WCM).The Condamine Valley hosts highly productive agricultural land with groundwater resources heavily utilised for irrigation. Water demand outstrips available supply and groundwater has been subject to restrictions on further development since the early 1970s. Developments that could have an additional impact on groundwater resources in the CA are of major concern to local landholders. This paper describes: planned field investigations at two sites: 1. Stratheden, where pumping from the WCM will be undertaken 2. Daleglade, where pumping from the CA will occur how the data to be collected from field investigations will be used to refine predictions of flux between the CA and the WCM.CITATION:Denner, S, Gossmann, S and Barlow, J, 2013. Planned field investigation of connectivity between the Condamine Alluvium and Walloon Coal Measures, in Proceedings Water in Mining 2013, pp 91-98 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

By Potter OE

There appears to have been a swing away from the study of mathematics, the physical sciences, foreign languages and the classical humanities subjects by many students in high schools in Victoria. The same trend is believed to be occurring in other states as well. This has the direct result of many students entering tertiary studies inadequately prepared academically. This is particularly true in engineering and commerce. The position as far as postgraduate training in the areas of concern to the minerals industry is critical with almost no Australian nationals undertaking advanced technological studies.

Jan 1, 1981

By James W. Martin, Robert R. Faddick

INTRODUCTION Virtually every sector of society in our country feels the impact of tunnels, either through the transportation of water, commodities, or people. The economic implications are staggering. The Committee on Rapid Excavation (1) reported that during the near future, 1968-1975, underground excavation activity will comprise 946 miles of tunnels (subways: 85 miles; underground urban highways: 123 miles; intercity highway tunnels: 210 miles; water supply tunnels: 528 miles) and 5,119 million tons of crude ore; metals: 874 million tons; nonmetals: 899 million tons; and coal: 3,346 million tons. It is estimated that the cumulative demand for underground excavation in the decade 1970-1979 will be 13 billion dollars for construction-oriented demand and 16 billion dollars for mining-oriented demand. The respective figures for the decade 1980-1989 are estimated at 22 billion dollars and 18 billion dollars. Of the many advantages claimed for tunnels (2, 3, 4, 5) the environmental considerations are becoming increasingly important. Transportation tunnels particularly for rapid transit systems, offer reductions in noise pollution and air pollution while improving aesthetics and optimizing land use (fewer problems of right-of-way and disruption of utilities). Considerable interest has been shown recently in sub-surface construction and mining (6, 7, 8). Recognizing the future demands for tunnels has led to considerable study of methods to improve rates of tunnel advance per day, safety, and the overall economics. The search for higher rates of advance has Led away from what has heap termed conventional methods (drilling

Jan 1, 1974

By W. W. Odell

ONCE it was believed that anthracite or coke were the only fuels generally available and suitable for the generation of water gas, particularly so when this gas was made in the generators of standard carburetted water-gas sets such as are commonly used in the manufacture of city gas. During the past 8 years, practice has changed considerably and it is -now common to find gas plants operating without anthracite or coke and using bituminous coal in the generator. This change in fuel has appreciably increased the marketability and sales of certain coal producers&apos; products; accordingly it is of interest to coal operators and others to know the reason for this change, the present trend in practice and the adaptability of various coals for generation of water gas. This paper briefly discusses these conditions and some of the factors relating thereto. BITUMINOUS COAL NOT IDEAL BUT CHEAPER THAN COKE In spite of many changes which have been made in both process and generating apparatus for using bituminous coal as generator fuel more efficiently, in general it is not an ideal fuel for this purpose. It is supplanting coke because it costs less; it is so much cheaper per ton delivered at the gas works that water gas made therefrom costs less per unit-volume than that made from coke, even though the quantity of generator fuel consumed per therm (100,000 B. t. u.) of gas made is greater with coal. This is the reason why so many city gas plants, as well as others, are using bituminous coal instead of coke.

Jan 1, 1927

By Ben Bowman

For certain ferroalloy furnaces, such as ferrochrome or ferromanganese, there is still doubt about the mechanisms operating under the electrode tips. In this paper a model is built that does not call upon an arc. The medium is best described as an electrically conducting slurry, a mixture of liquids, solids and gas. There are two sources of propulsion, the Lorentz force within the conducting part and buoyancy generated by CO bubbles, creating two opposed poloidal circulation loops, downward below the electrode axis and upward further out.

Jan 1, 2014