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By T Wettainen, G Shekhar, M Stromsten, B Skawina

The aim of a transportation system in an underground mine is to move the rock masses from one location to another in the most preferable manner by minimising the long and short-term operational costs. A continuous improvement of material transportation systems used in mines generates a need for continuous investigation of the current and new underground transportation systems. In an underground mine, an orepass is a common system used to transfer the material to the lower levels. If this system loses the ability to transport or store the necessary material capacities, it would result in production disturbances. In this paper, discrete event simulation (DES) was utilised to analyse the material inflow and outflow of the orepass systems when subjected to the different conditions. The study presented in this paper is based on the Malmberget mine, the second largest underground sublevel caving (SLC) iron ore operation in the world.

Mar 15, 2021

By Jason J. Ballentine

This case study presents the results of a maintenance review of a soot blower system at a coal fired power generation station. The power generation station was following a ?repair when it breaks? maintenance strategy for its soot blowers. The efficiency losses incurred as a result of failures in the soot blower system and the resulting interruption and out of service time was found to have a significant effect on the plant output. The maintenance strategy for the soot blowers was reviewed using Reliability Cantered Maintenance and lifecycle simulation. This methodology provided visibility to the monetary implications of failures and allowed alternative types of maintenance to be assessed and where justified were added to a maintenance schedule in the Maximo work order management system. By reducing unplanned breakdowns the predicted reduction in efficiency losses was 45%.

May 1, 2007

Silver is one of the three major metals produced from the Broken Hill mines. The accurate determination of the silver in these ores, therefore, is of economic importance.With due appreciation of the divergence of opinion of many who are interested in the subject of the determination of silver, the writer has been prompted to present the results of some recent experiments on silver losses during cupellation and conclusions from these experiments in the present paper. The losses of silver in the fire assay for this metal are due to silver retained in the slag during the fusion or scorification of the ore, and to silver volatilized from, and absorbed by the cupel during the process of cupellation.The literature describing the results of experimental work on silver losses due to the above causes is extensive, and the general conclusion of these experiments is that the silver lost in the slag is small, but that lost by cupellation is larger and more variable.The term cupellation loss in this paper refers to the total cupellation loss, no distinction being made between the absorption and volatilization losses.Volatilization loss is shown by King to be 0.5% of the total cupellation loss and, as it is generally accepted among assayers as being only a small fraction of the cupellation loss (3) (5), it will not receive further consideration in this paper.The factors causing the loss of silver by cupellation and the precautions to be obs~rved to reduce the loss in this operation are described in (1), (2), (3), (4) and (5). The...

Jan 1, 1940

By J. W. Thompson

"The recent discovery and exploitation of petroleum territory have resulted in the enactment of new petroleum laws in most of the South American Republics. The activities in the discovery of these new fields were engendered by the knowledge of the fact that present producing fields must within well defined periods be exhausted. Oil operators were willing to take the initial steps in exploitation in the absence of legislation that applied strictly to petroleum operations. The enactment of modern legislation in many of these Republics encouraging and protect¬ing exploitations may cause tremendous oil activities in these countries, and the results may be comparable with the magnitude of the undertakings and the prestige of the companies now entering this territory.These, oil fields are admirably located for convenient distribution of petroleum by water to all the Nations using oil as fuel for shipping and industrial concerns. The oil markets of the western coast of South America will derive immense benefits from the Panama Canal. This navigation route brings these markets into direct ocean shipment with the Atlantic coasts of the Western and Eastern Hemispheres.One deterrent to oil production in the Republics of South America is the want of inland. transportation facilities, but the recent laws of these Republics without exception provide for acquiring rights of way for pipe lines and other modes of transportation; and doubtless the great interests and. syndicates already operating in these regions will, as production increases, provide ample pipe line transportation sufficient to convey to the coast the oil produced. It way be assumed, from the legal guarantees afforded, and from operating equipment and machinery that are now being concentrated that refineries will be erected at shipping points for the purpose of making these petroleum products accessible to the world."

May 1, 1921

By Walker BV

Mining activity has been an integral component in the New Zealand economy since the early days of European settlement. Recently in common with other Pacific Rim countries there has been a resurgence of investment in gold. A sustained and increasing exploration effort has resulted in the rapid development of alluvial gold mining operations, a number of hard rock gold discoveries, and a general optimism about New Zealand's prospectivity. New Zealand's attitude to mining development, in particular hard rock gold mining is influenced by high environmental values and a concern, largely through absence of examples, that modern mining may not perform to community standards. While these environmental concerns are wide spread there is a growing realisation that gold mining, if properly managed, can take place within acceptable environmental standards and that it has the potential to contribute significantly to New Zealand's economy. New mining developments have an important role to play in this process. The mining industry in New Zealand is now at a crossroads. Having invested substantially and confirmed the potential for gold mining developments it has found itself in a rapidly changing economic environment as the Labour Government puts in place a number of fundamental economic reforms. The reforms are intended to free up the economy removing the rafts of subsidies and protective measures which have stultified initiative and growth. A fundamental reform of the public service has been initiated including corporatisation of trading activities and the establishment of a Department of Conservation to administer estensive areas of Crown land. Both petroleum and mining taxation are being reviewed with the intention of creating a more neutral competitive environment. Mining legislation is also being re-examined with both efficiency and equity objectives. While the current environment is characterised by uncertainty and rapid change, the outcome will be a more market-oriented stable policy environment, to the mutual benefit of the industry itself and the New Zealand Community.

Jan 1, 1987

By Tassos Grammatikopoulos, Sarah Prout, William Mercer, C. Gunning

"The Nechalacho rare metal deposit is located in NWT, Canada. Avalon Rare Metals Inc. is now evaluating processing techniques for recovery of REE to be used in the industry. QEMSCANTM analysis coupled with whole rock, REE, Zr and Nb, and electron microprobe analyses were utilized to identify and quantify the mineralogy of the deposit, and define the REE distribution among minerals. QEMSCANTM mineralogy was performed on fifty intact drill samples using EXPLOMINTM that provided textural information for the mineralization; crushed samples were used to determine the variability of the ore and define REE domains, and composite samples to determine the liberation and association of the REE minerals. The sample matrix predominantly consists of biotite, feldspars, quartz, muscovite/clays, minor chlorite and amphibole, magnetite and hematite and carbonates. REE include in decreasing order of abundance allanite (3.6%), monazite (1.5%), synchysite (0.9%), columbite (0.9%), fergusonite (0.6%), bastnaesite (0.4%), and zircon 11.0%. The majority of the HREE are carried by fergusonite and zircon, and the LREE by monazite, allanite, synchysite and bastnaesite. QEMSCANTM mineralogical data is extremely valuable in assessing the mineralogy of the ore. The data have been implemented in defining the mineralogy of the ore body, support metallurgical test work, predict recoveries and grades, and finally calculate reserves of the deposit.INTRODUCTIONAvalon is in the unique position of owning and developing one of the world’s largest rare earth deposits in the Northwest Territories of Canada.The term Rare Earth Elements (REE) is used to describe the 15 lanthanide elements or metals and, more recently, the metals yttrium and scandium, which display similar physical and chemical properties. REE are not particularly rare and have a similar abundance in the earth’s crust to nickel, tin or tungsten. Unlike these better known metals however, the rare earths have little tendency to become concentrated into commercial ore deposits. When they do become concentrated, deposits of REEs usually display enrichment in one of two groups. The most commonly occurring deposits of REEs contain a sub-group of elements referred to as the “light rare earth elements” (LREEs), which include lanthanum, cerium, praseodymium, neodymium, and samarium. Less commonly, deposits of REEs contain the much more valuable sub-group of elements referred to as the “heavy rare earth elements” (HREEs), which include europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. Yttrium and scandium most commonly occur in association with this second HREE sub-group. Generally, LREEs are produced from the mineral bastnaesite, and the HREEs have been produced from the minerals xenotime and monazite. LREEs continue to be produced from bastnaesite, however in the 1980s, China started production of HREEs from unique laterite clay deposits. China now produces approximately 95% of the world’s rare earths."

Jan 1, 2011

By J P. Barkas

World demand for iron ore is far from peaking, and the substantial price decline that has captivated commentators since early 2014 is not the result of widespread misreading by producers of the prospects for global market growth. Recent price movements provide little useful insight into the industry’s longer-term fortunes, apart from reminding mining companies that their businesses need to be robust against the volatility and inescapable cyclicality of mineral commodity markets. It is timely to take a strategic view of the history and longer-term prospects for the iron ore industry and of Australia’s place in it.CITATION:Barkas, J P, 2015. Perspectives on the long-term outlook for iron ore, in Proceedings Iron Ore 2015, pp 3–6 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By Dimas Henrique Barros Andrade

No cenário atual de empobrecimento da qualidade das matérias-primas carregadas nos altos-fornos, torna-se fundamental compreender os fenômenos que afetam diretamente a estabilidade operacional desses reatores. Este trabalho avaliou uma relação entre queda de pressão e intensidade de irrigação com a intenção de associá-los aos fenômenos de retenção e refluxo que ocorrem na zona de gotejamento de um alto-forno a coque. Não foi possível obter claramente uma relação entre as instabilidades operacionais e a ocorrência de fenômenos de inundação, porque não há uma separação clara entre os dias com e sem as instabilidades operacionais. No entanto, ao longo de um intervalo definido no diagrama, é notável uma maior ocorrência de instabilidades. Analisando os parâmetros, o que tem maior influência na permeabilidade da zona de gotejamento é a distribuição do tamanho do coque, avaliada pelo cálculo do diâmetro harmônico.

Oct 30, 2017

By Richard P. Curtin, John M. Goris, Lewis A. Martin

Cable bolt supports are being recognized as an effective ground control system in under-ground coal mines in North America, and their use has increased considerably during the past few years. The U.S. Bureau of Mines personnel are conducting both laboratory and field tests to evaluate the performance of these supports under a variety of conditions and to establish realistic design guidelines. This paper describes efforts to evaluate the capability of cable bolts to resist the high shear forces often present in longwall operations. Shear tests were conducted on pairs of 0.025 m3 (0.88 cu. ft) concrete blocks having joint surfaces ranging from rough to smooth. Tests were conducted on blocks both with and without reinforcement with 15.2 mm (0.6 in.) diameter steel cables. During each shear test, the loads and displacements along the normal and shear axes, as well as loads on the cable, were monitored. Cableloads were determined using strain gauges attached to the outside surfaces of the barrel-and-wedge anchors used for pretensioning the cables. Test results show that a cable bolt placed across a joint more than doubled shear resistance of shear blocks having both smooth and rough joints.

Jan 1, 1996

By J. B. Austin, R. L. Rickett

MEASUREMENTS Of the rate of decomposition of austenite at constant temperature are commonly represented by plotting the percentage transformed on linear coordinates against time on either a linear or a logarithmic scale, a method that yields a curve that in shape resembles an integral sign (Fig. 1). A graph of this kind is not always convenient because extrapolation to the beginning or end of the transformation, or even interpolation, may be uncertain unless there are a large number of observations, which seldom happens; furthermore, the degree of consistency of a set of measurements is difficult to judge from such a curve. It is desirable therefore to find some mode of plotting, or even better to find a standard variety of graph paper, that gives a straight line instead of the integral shape. The straight line has many advantages; the number of readings required to fix the position of the curve is greatly reduced, interpolation is easy and rapid, extrapolation can be carried out with greater confidence and, finally, the consistency of the measurements is readily estimated from the scatter of the points. The last advantage is particularly valuable when the data are obtained by direct microscopic examination alone, because they are influenced by the skill of the observer in estimating the relative size of areas, possibly also by undetected inhomogeneity of the specimen. A search for ways of representing the observations as a straight line yielded two methods which are described in this paper. The paper also includes an account of some interesting relations brought to light in applying these methods to the available experimental data. Usually the best way to derive such a method of plotting is to base it on established principles of chemistry and physics, as has been done, for example, for the temperature variation of the equilibrium constant of a chemical reaction. But so little is known of the mechanism of the decomposition of austenite, and so little is available in the way of well established background for changes of this kind, that it is simpler to rely upon purely empirical means. The general plan therefore is to study existing data with a view to finding some function of the direct observations that will

Jan 1, 1938

By Lex B. Golden

The purpose of this investigation was to evaluate the corrosion properties of certain alloys of titanium and to compare them with those of unalloyed titanium. Such information should make it possible to determine the desirability of substituting these alloys for commercially pure titanium in certain applications. Titanium-manganese, titanium-chromium-iron, and titanium-vanadium-iron alloys, with 2 types of unalloyed titanium, I consolidated by arc melting and the other by powder-metallurgy techniques, were included in the study. Tests were carried out in sulfuric, hydrochloric, phosphoric, nitric, and mixed acids and in chloride solutions. All solutions were saturated with air.

Jan 1, 1957

By P. Nelson, B. Salt, J. A. Scott, H. Shang

ABSTRACT In a nickel smelting process, large amounts of off-gas emissions are generated, which can cause serious environmental and plant hygiene problems if not properly treated. With increasingly stringent environmental regulations, an enhanced understanding of well-controlled, off-gas cleaning systems is vital. In this paper, dynamic models for an industrial smelter, off-gas system tackling hazardous sulphur dioxide, carbon monoxide, and carbon dioxide are developed using mass continuity, momentum, and energy conservation laws. The effect of air in-leakage is explored under different operating conditions. The developed models provide an enhanced process understanding and a necessary basis for highperformance control analysis of smelter off-gas systems.

Jan 1, 2011

By R. P. Singh

A mine fire model gallery has been designed and constructed on the premises of the Central Mining Research Institute, Dhanbad, India to perform systematic in-depth studies on various aspects of mine fires. The gallery is 65.5 m long and 5.86 m2in cross-section and it is divided into firing and non-firing zones. It is equipped with a computer-aided online telemonitoring system that has 130 sensors, two data loggers and computer peripherals for continuous recording of various fire parameters. A fan to generate airflow through the gallery has been installed at its end. Two sliding doors and one rolling shutter were also provided for sealing and regulation of airflow. Two sets of experiments have been carried out in the model gallery maintaining air velocity of 1 and 1.5 m/s through it. In the experiments, the inner sides of the firing zone, 22 m in length, were lined with a thin layer (8?10 cm thick) of coal slabs. Two fire suppression techniques viz. flushing of liquid nitrogen (LN2) and infusion of high pressure high stability (HPHS) nitrogen foam were tried to quantify their effectiveness under dynamic fire conditions. The paper addresses important design features of the gallery, its instrumentation system, the experimental procedure adopted and important findings from the experiments. It has been observed that the intensity of the fire was very high after one hour of its initiation and continued for 3?4 hours. During the period, frequent backlash with smoke and flame was noticed. The efficacy of the fire suppression techniques has been assessed interms of reduction in temperature, generation rate of CO2and CO, and heat release rate. The study reveals that high pressure high stability (HPHS) nitrogen foam is more effective in controlling open fires than liquid nitrogen is. Keywords: Model gallery, telemonitoring system, velocity, temperature, pressure, gas concentration, intensity, liquid nitrogen, high pressure high stability nitrogen foam.

Jan 1, 2004

By R F. Sandenbergh

Due to environmental considerations, mineral processing plants are increasingly recycling water to decrease the impacts of wastewater on environment and the depletion of fresh water resources. Industrial experience has shown that increasing recycling water in flotation typically negatively impacts the recovery and selectivity, especially in the selective flotation of minerals from complex sulfide ores. The major reason for the reduced selectivity is typically the inadvertent activation of sphalerite or pyrite by the heavy metal ions (HMI) in solution. These HMI are often produced during milling and flotation and absorbed by other minerals. In the normal flotation pH value range (8 - 10), these HMI are often in the form of precipitates or complex ions that may re-appear in solution or become active should conditions favour this. In this paper, microflotation, batch flotation and XPS surface measurement were used to investigate the use of HMI absorbents additions to the pulp to improve flotation selectivity of a complex sulfide ore. It has been demonstrated that HMI removal does improve flotation selectivity by facilitating more effective depression of the sphalerite. Microflotation and XPS surface measurements have shown that HMI absorbents compete with sphalerite to absorb HMI, and thus reduce the surface concentration of HMI on those sulfides. The practical use of HMI absorbents in complex sulfide ore flotation is also discussed.

Jan 1, 2005

By D. Jenkins

THE Franklin Laboratory was designed mainly for the analysis of the products from the two concentrating mills situated at Franklin and Sterling Hill, the most important determinations being the zinc, iron, manganese, lime, moisture and silica contents of the ores. Within the last 4 years, however, it has been found advisable to examine most of our supplies, and therefore additional space and equipment was allotted for the examination of such substances as oils, greases, soaps, alloys, fuels, paints, explosives and water. The building as shown in elevation (Fig. 1) and plan (Fig. 2) consists of a main or routine laboratory, an experimental laboratory, a water FIG. 1.-WEST ELEVATION. analysis room and the other accessories such as stock room, library, sampling and drying rooms and office. The main laboratory is further divided into a balance room and zinc analysis room. As the greater part of our determinations are volumetric, good light is a very important factor and with this in view the interior walls of the building were constructed of white enameled brick laid in Keene cement. These also have the additional advantage that they give a clean and attractive appearance to the room. The windows are large, being 76 by 44 in. and even on very dark days the light is good throughout the whole laboratory. Our zinc titration requires a constant light and as, on many days, especially in winter, the light is variable, we installed two Artificial

Jan 8, 1917

By W. Blum

Progress made in improving the creep resistance of Mg alloys is reviewed with the emphasis on microstructural interpretation. Experimental results on the increase of creep strain with time at constant stress a measured for limited times and strains are displayed in a transparent form as creep rate-strain diagrams from which the minimum creep rate stress is safely derived. In addition, data on the thermal stress component a derived from high-precision a-reduction tests are reported. Within a simple statistical dislocation model these data allow one to quantify the relation between dislocation velocity v and a . In combination with structure evolution laws this relation serves as a basis for modeling the creep rate. New alloys have distinctly higher creep resistance than AZ91 where precipitation hardening plays a minor role. This is due to hardening by intermetallic phases which may form a continuous skeleton along the grain boundaries (e.g. Ca-alloyed AZ91) and/or submicron-sized precipitates within the grains (MRI230D, Mg-Zn-Ca alloys).

Jan 1, 2006

By J. M. Stuve

Low-temperature heat capacities of chiolite (Na5Al3F14) were determined by adiabatic calorimetry in the temperature range 5.8 to 300 K. The derived standard entropy (S°, 298.15) was 115.6 ± 0.2 cal/deg-mole. High temperature enthalpies relative to 298.15 K were obtained by precision drop calorimetry up to 1,000 K. Tables of experimental data and related thermodynamic functions are given for the temperature range of experimental observations.

Jan 1, 1980

By T. B. Williams

Most geologists have felt the need of a longer base than is ordinarily available when using a Brunton compass or other convenient instrument for taking strikes and dips in the field. To overcome this difficulty a lath or stick with straight parallel sides is frequently used. This accessory adds to the accuracy of the work, but it is a decidedly inconvenient one for the geologist to carry, especially if he be heavily loaded or is travelling on horse-back or through thick brush on foot. The writer has abandoned its use in favour of a sturdy two-foot carpenter's rule. The rule preferred is manufactured by J. Rabone and Sons, Birmingham, England. It is provided with a good level-bubble set in one of the limbs, and a scale, of the protractor type, graduated to five degrees through 180 degrees, attached to the main joint at the middle of the rule. (See Figure 1). For an instrument of its kind it is very accurate, and, in addition to the uses mentioned below, it 'is a handy thing to have around any camp. It is frequently used when plotting roughly in the field and for a protractor when one is not available. When not in use it may readily be carried in the top of the high-boot or legging. Ordinary strikes are measured as illustrated in Figure 1, the compass being held against the rule, which is in a horizontal position. Dips may be measured in a corresponding way by holding the Brunton compass against the extended rule, which is thus used merely as a straight edge. It is usually much more convenient, however, to ? use the rule only for this purpose, in which case one foot of the length rests as a straight-edge against the rock surface. This adaption is shown in Figure 2.

Jan 1, 1929

By G. Reinberg, C. D. Clarke

Most underground mining operations are dependent on pumping installations to keep the mine unwatered. The reliability of such installations is obviously of paramount importance. The volume of water to be handled is often considerable, and the total head is relatively high. In these cases, both capital cost and operating expense of the pumping installations will become significant factors in overall mining costs. To insure reliability and to keep efficiencies, and hence operating costs, within acceptable limits it goes without saying that mechanical maintenance of a mine pumping installation must receive scrupulous attention at all times. Large mine pumping installations today almost invariably use multistage centrifugal pumps, since positive-displacement units would not be economically competitive except under very unusual conditions of small volume combined with extremely high heads. Centrifugal pump maintenance, under ideal circumstances, would be confined to parts subject to normal running water, i.e., bearing surfaces, stuffing box packing, and shaft sleeves. Under adverse conditions, however, metal may be lost from the wetted surfaces of a pump by erosive or corrosive action of the pumped fluid, and maintenance costs can easily attain enormous proportions.

Aug 1, 1956

By D. Duvris

The main objective of this work was to quantitatively investigate exhaust emission levels relative to maintenance (service) intervals during the operation of diesel-powered equipment at an underground bauxite mine in Greece. Such emissions depend on a great number of parameters, including the type of engine (technology) and its tuning, the type of work performed (as related to the engine workload), the suggested maintenance intervals, the altitude, the temperature and humidity of the atmosphere in the underground mine, the properties of the fuel and the operator's training and experience levels. The necessary ventilation quantities were calculated based on exhaust gas-concentration measurements and site-specific relationships between pollutants and adjusted air-quality indices. Diagrams comparing the necessary and recommended airflow for several equipment groups, featuring two engine types and different maintenance intervals, are presented.

Jan 1, 2000