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By B. Morris

This presentation will describe the process by which the Quebrada Blanca (QB) copper project in northern Chile was financed. It will also show how a relatively junior mining company addressed the problems created by its inability to provide its share of the equity funding and the guarantees required by the project lenders. QB is located in the semi-arid Andean highlands of northern Chile, 170 kilometres southeast of the port of Iquique and 30 kilometres west of the border with Bolivia, at an altitude of about 4,300 metres (14,000 feet). Figure 1 depicts the project's location. The QB orebody is a secondarily enriched porphyry copper deposit containing reserves of 85 million metric tons grading 1.3 percent copper. Underlying the enriched zone is a significant primary ore zone containing several hundred million metric tons grading about 0.5 percent copper. In the late seventies and early eighties Falconbridge and its affiliates spent $20-30 million dollars exploring the deposit and conducting feasibility studies. For a variety of reasons they decided not to develop the property which was returned to its owners, Empresa Nacional de Mineria (ENAMI), which is a Chilean state mining corporation. In 1988 ENAMI announced its intention to privatize the property through a public bidding procedure.

Jan 1, 1993

By G. J. Simandl

"Since the 1980s, China has become the predominant producer of REEs. Recently, it introduced REE export quotas and this started a world-scale REE exploration rush. REE resources are concentrated in carbonatite-related deposits, peralkaline igneous rocks, pegmatites, REE ± P veins, ion adsorption clays, placers, and some deep ocean sediments. REEs could also be derived as a by-product of phosphate fertilizer, U processing, Ti-Zr-bearing placers, and exploitation of Olympic Dam-type sub-type of IOCG deposits. The ideal REE development target would be located in a politically stable jurisdiction such as Canada. REE grade and tonnage, mineralogy, and permissive metallurgy are some of the key technical factors that could be used to screen projects. INTRODUCTIONAccording to the International Union of Pure and Applied Chemistry (IUPAC), the term “rare earth elements” (REEs) encompasses yttrium (Y), scandium (Sc), and the lanthanide series: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). This definition is used throughout this paper.REEs are subdivided into light (LREE) and heavy (HREE) categories. LREEs include, Sc, La, Ce, Pr, Nd, Sm, Eu, and Gd and HREE include Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y. Promethium (Pm) does not occur in nature. Concentrations of individual LREEs in the upper crust of the Earth are comparable to those of base metals. Even the least abundant REE (Lu) is about 200 times more abundant than gold.The production of REEs, reported in the form of oxides (REOs), for 2011 is estimated at 140 000 t (Figure 1a). Although high technology industries can substitute several REEs with other materials, these substitutes are typically more expensive or less effective than the REEs they replace. A number of countries, including the United States, consider several REEs essential for national security, their economy, and a general reduction in green house gas emissions. The forecasted demand for individual LREOs is much higher than that of HREOs (Figure 2). Dy, Eu, Tb, Nd, and Y are essential for the US economy and subject to predicted supply disruptions (U.S. Department of Energy, 2010)."

Jan 1, 2012

By S. N. Titkov

Flotation of halite?new, recently begun to be developed method of processing water-soluble minerals. In the paper the results of studies of the new directions of the application of halite flotation are represented. Studies on the flotation separation of halite and sylvite in the salt solutions of different composition, showed the possibility of the halite flotation realization not only in the carnallite brine (content of salts: MgCl2 25.5% ~ 26.0 %, chlorides of potassium and sodium 5.5% ~ 6.0%), but in the sylvinite brine, which contains 10.5% ~ 10.8% KCl and 20.5% ~ 21% NaCl. On the basis obtained results are carried out experiences on the halite flotation from samples of the converted products of sylvinite ores by flotation method and by the method of the electrostatic separation. It is shown that in all cases it is possible to accomplish effective and selective recovery of halite. The halite recovery into the foam product of flotation makes 80% ~ 90% with an increase in the content of KCl in the cell product of flotation in comparison with a composition of flotation feed: - from the product after the electrostatic separation of ore ? from 76% KCl to 95% ~ 97% KCl; - from the small fraction of ore (- 0.25 + 0 mm) ? from 30% KCl to 60% ~ 64% KCl; - from middlings (intermediate products) of sylvite flotation from 16% ~ 31% KCl to 45% ~ 80% KCl. An increase in the molecular weight of alkylmorpholines increases the selectivity of the flotation separation of halite and sylvite. Halite recovery from small size fraction of ore or/and middling of sylvite flotation with the sub-sequent joint filtration halite product and tails of sylvite flotation allows to reduce considerably expenses for manufacture potash chloride from Pilot-industrial tests for the first time confirmed the possibility of the effective halite flotation in the saturated solutions of chlorides of potassium and sodium (sylvinite brine).

Jan 1, 2014

By X Zhang, B McFadzean, C T. O’Connor, S Pikinini

The Platreef in South Africa contains one of the world’s largest reserves of platinum group elements. One of the major platinum group minerals (PGM) components in this ore is sperrylite (PtAs₂), which has been found to be slow floating compared to the other PGMs. In a study aimed at determining the reasons for the poor floatability of sperrylite and to improve its recovery, tests were carried out to determine the interactions of the mineral with a range of standard and novel collectors. Microflotation tests were carried out to determine the hydrophobicity of the minerals before and after adsorption of collectors. In addition, experiments were carried out to determine the enthalpy and extent of collector adsorption on the minerals and to investigate electrochemical interactions between sperrylite and selected standard collectors. The results indicated that poor collector adsorption was the major cause for the poor floatability of sperrylite. Sperrylite had both poor natural (14.5 per cent) floatability and collector-induced flotation recoveries, the highest recovery of 26 per cent being observed using PNBX collector at pH 9. Moreover, the rest potential tests showed that the interaction of sperrylite with standard collectors such as xanthates was poor. The decrease in potential after the addition of the standard collectors ranged from 7.9 mV to 24.9 mV under alkaline conditions. Furthermore, sperrylite rest potentials remained unchanged with a change in pH from basic to acidic, indicating its resistance to surface alteration. Surface alteration of the minerals is key for the chemisorption of collectors to take place on the mineral surface. This was further emphasised by flotation recoveries at low pH, where only certain collectors responded positively to a decrease in pH and these were shown to have undergone a structural change. This work has highlighted the difficulties associated with sperrylite flotation and provides some direction for future research.

Aug 24, 2022

By Albert Sauveur

IT WAS in June, 1889, that I was first admitted to the society of educated men. The admission ticket had been signed, on the recommendation of my old and beloved teacher, Bobby Richards, by General Francis A. Walker at the time President of the Massachusetts Institute of Technology, an institution familiarly known as M. I. T. I immediately proceeded to take advantage of that privilege by departing for Steelton, Pennsylvania, where I understood I was eagerly awaited by the educated officials of the Pennsylvania Steel Company. I was some. what disappointed at the casualness of my reception and at being tucked away in that preserve closet of steel works known as the chemical laboratory. At Steelton I met Major Bent who was president of the company. When I say "met," that is a figure of speech as my acquaintance with him was confined to my being shown

Jan 1, 1937

By W. R. Reed, G. W. Luxbacher

Mine worker exposure to respirable coal dust and silica dust can result in coal workers’ pneumoconiosis and silicosis which are occupational respiratory diseases that have no cure and are ultimately fatal. In 2021 the Mine Safety and Health Administration reported just over 11,000 operating metal/nonmetal mines with the potential for silica dust exposure for just under 200,000 miners. The National Institute for Occupational Safety and Health (NIOSH) conducts respirable coal and silica dust research associated with mining through its Office of Mine Safety and Health Research. NIOSH respirable coal and silica dust research began under the U.S. Bureau of Mines (USBM), which initially examined silica dust, progressing to include coal dust, with a stronger focus after 1969 with the passage of the Federal Coal Mine Health and Safety Act. A review of extramural research to develop real-time respirable silica dust monitor is presented along with a brief history of silica dust regulation.

Feb 1, 2024

By T Roberts

The transition of mechanical cooling refrigerants from their inception in the 1800s through to the current day has been driven by several factors. Original refrigerants such as sulfur and carbon dioxide, chloromethane and ammonia, whilst effective came with toxicity and/or flammability issues. In 1930 DuPont trademarked a new synthetic refrigerant known as Freon® 12, this development was the introduction of ‘chlorofluorocarbons’ (CFCs).Throughout the 1930s and 1940s additional synthetic refrigerants were developed, namely Freon® 11 and Freon® 22. Due to their non-toxic and non-flammable characteristics, synthetic refrigerants were extensively used for domestic, commercial and industrial applications for the next 60 years.In 1985, one of the first scientific papers suggested a potential mechanism linking CFCs and areduction in the density of the ozone layer. In 1987 the Montreal protocol is ratified; it is the first UN treaty to be ratified by every country on earth. Due to CFC’s ozone depletion potential (ODP), the treaty required the consumption of CFC’s to be reduced by 50 per cent over the next ten years. By 1996 the phase out of CFC’s (Freon® 12) is completed, the phase out of HCFC (Freon® 22) refrigerants comes into effect.On 1 January 2018 the phase down of HFC’s begins. Whilst having zero impact on the ozone layer HFC refrigerants have high global warming potential (GWP). As we transition through the HFC phase down (2018–2035) we are beginning to see the emergence of what some consider to be the fourth synthetic wave, hydrofluoro-olefins (HFO’s). HFO’s and their blends have zero ODP and low GWP’s, ranging from 150 to less than 1. The reduction in GWP with HFO’s typically comes at the expense of flammability, which is not ideal. Each refrigerant has its optimal application, therefor when considering refrigerant choices for mining systems, a complete assessment of the environmental, health and safety, efficiency and commercial impacts should be considered now more than ever.

Oct 12, 2022

"6.1. Mineralogical Techniques ApplicableTo the Platinum-Group Elements6.1.1. IntroductionThe named platinum-group minerals (PGM) usually occur as grains smaller than about 200 microns and, even when present as larger grains as in nuggets, these are often complex multimineral intergrowths. Therefore, the PGM must be examined by microscopic techniques and, because all named PGM are opaque, they are suitable for microscopic study by reflected light. Special techniques for concentrating PGM and preparing suitable polished sections are detailed in Chapter 5. Another characteristic of the PGM is that the majority have very high reflectance at 589 nm, i.e., over 450Jo, but they range from about 38 to 74%. In contrast, micro-indentation hardness has a wider range from - 60 to - 3,000 kg I mm, and the PGM range from brittle to malleable.The small grain-size of PGM imposes certain limitations, or complications, on the usual mineralogical determinative methods of reflectance, micro-indentation hardness and X-ray diffraction. In addition, certain combinations of elements in some PGM render electron-probe analyses difficult. The usefulness and shortcoming of these methods, as applied specifically to the PGM, are discussed in the following sections. These are not, however, meant to be exhaustive descriptions of the techniques, which are fully described in other texts.6.1.2. Micro-Indentation HardnessDetermination of the Vickers Hardness Number (VHN) is discussed in detail in recent publications, such as Bowie and Simpson (1977) and Craig and Vaughan (1981). In addition, the recommendations of the Commission on Ore Microscopy (COM) of the International Mineralogical Association (IMA) are given by Criddle (1980). The usual small grain-size of the PGM, however, precludes the widespread use of this technique and very few PGM have, in fact, had their VHN determined at the COM-recommended standard load of 100 gf (cf. Cabri, 1981b, in Chapter 7). Examination of VHN data reported in the literature reveals that the few PGM whose microindentation hardness has been measured have incomplete VHN data, measured with loads other than 100 gf (Chapter 7). The small grain-size may also result in unreliable VHN data because, even though the correct load may have been applied, a thin grain will give erroneous data due to the matrix, or the grain may even shatter or pop out of the section. On the other hand, micro-indentations may give useful qualitative diagnostic clues. Moncheite, for example, shows fractures near the indentation (Chapter 7, Plate 1). In other cases, intergrown PGM produce different-sized indentations: e.g., froodite-michenerite-gold in Cabri (1972); isoferroplatinumtulameenite in Cabri et al. (1973); michenerite-moncheite in Cabri and Laflamme (1976) and Chapter 7, Plate 1; altaitemichenerite- testibiopalladite in Hudson eta/. (1978) and Plate 1, Chapter 7."

Jan 1, 1979

By Erika Moonin, Jim Nickerson, Claudio Cimiotti, Roberto Bono

"In response to the severe drought on the Colorado River basin and in order to preserve existing water capacity to the Las Vegas Valley, the Southern Nevada Water Authority contracted a new deep-water intake (Intake No. 3) located in Lake Mead. The current project (Contract No. 070F-01-C1) includes 5 km (3 miles) of tunnel with very difficult geological conditions and a 200- m (650-ft) deep shaft and marine works. This paper will present the current status of the design-build contract being constructed by Vegas Tunnel Constructors and the challenges and problems faced and the innovative solutions developed to handle the difficult conditions encountered during tunneling with up to 15 bars of pressure.ProjectbackgroundThe Las Vegas Valley receives the majority of its water from Lake Mead, which is located approximately 30 km (20 miles) east of the Las Vegas, NV metropolitan area. Due to the severe drought that has hit the southwest region of the United States, the water level in Lake Mead has receded from its high water level of 372 m (1,221 ft) above mean sea level (amsl) to a low of 330 m (1,076 ft) amsl in June 2015. Should the lake level continue to fall, at elevation 320 m (1,050 ft) amsl, the current water intakes will not be able to draw enough water to meet the needs of the local area. The risk of losing water capacity has prompted the construction of a new deeper intake. Not only is the new Intake No. 3 situated at a lower elevation in the lake at 262 m (860 ft) amsl, the new Intake No. 3 is also located to draw better quality (Fig. 1).Project challengesThe project has had several difficult challenges to overcome:• The work consisted of a 1.2 kt (1,300 st) structure constructed on a barge and lowered 100 m (330 ft) into Lake Mead anchored with 9,200 m3 (12,200 cu yd) of tremie concrete.• The drill-and-blast starter tunnel was impacted by three inflow events, resulting in a one-year project delay.• One of the main challenges was selecting the tunnel boring machine (TBM) and excavating the tunnel with expected hydraulic head pressure of as much as 17 bar (16 bar was the highest pressure recorded during the drive), crossing faulted areas, low rock cover and the risk of tunnel instability due to direct connection with the lake.• Extensive pre-excavation grouting with a constant head pressure ranging from 12 bar to 15 bar.• Structural repair of the cutterhead in difficult hydrogeological conditions [water inflow of approx. 800 m3/hr (4,000 gpm)].• Complete repair of the cascade sealing system for the main bearing and two replacements of the pinion bearings.• The TBM approach to the intake structure."

Jan 1, 2015

By M. Prasad

Growing concern over increased levels of atmospheric carbon dioxide has prompted new interests in development of materials and techniques for its sequestration. Various research and developmental work on different aspects of carbon capture technology are being extensively carried out worldwide. The main objective of the present work is to synthesize a HAS material having high capacity and robust ability for recycling to capture greenhouse gases with special reference to carbon dioxide (CO2) from the sources from where it is released to the atmosphere. Existing CO2 capture techniques involves the use of solid materials that lack sufficient stability for repeated use or liquid adsorbents that are expensive and require significant amounts of energy. Keywords: greenhouse gases, carbon capture, solid adsorbent, HAS material

Sep 1, 2012

By Samuel B. Christy

Columbia College has the honor of founding the first well-organized School of Mines in America. The University of Michigan, however, shared with her the honor of graduating the first class, in 1867. Prof. Thomas Egleston was the pioneer in the new movement. He drew up the original plan for the Columbia School of Mines in 1863, and was in 1864 appointed its first professor. The Massachusetts Institute of Technology turned out a class of mining students a year later, and others followed in the order of their first graduating class, as shown in Table I., condensed from the Engineering News of August 11, 1892. Besides those mentioned, mining schools have been organized in the States of Arizona and Nevada, and more or less instruction is advertised in connection with other engineering schools. It will be noticed that Columbia easily heads the list with reference to the number of graduates; the Massachusetts Institute of Technology stands second ; the California University third, and then follow Lehigh, Washington University, the University of Michigan, Lafayette College, Michigan Mining School, Missouri, Colorado and the others. The total number of graduates from these 16 schools in 26 years, has been 871, or an average of 33 per year; but as all these schools give a partial education to many who do not graduate, it is probable that from 2000 to 3000 mining students have received from them considerable training. An interesting comparison of the rate of growth of the engineering schools has been recently instituted by the Engineering News, for the period between 1860 and 1892. Table 11. shows that civil engineering had the advantage in numbers from the start, and maintained the advantage until 2890, when it was surpassed by mechanical engineering. The development of the latter course may be said to date from 1880. There are many interesting facts evident in Table 11. It will

Jan 1, 1894

By C. Q. Cupps, R. F. Zaffarano, J. Fry

Reservoir oil analyses from seven wells in the Greater Clareton area have been included in a study of the original characteristics of oil in the Newcastle sandstone reservoir . These data correlated with areal location of the wells show an increase of saturation pressure in a general north - south or downdip direction . The increase amounts to about 500 psi in more than 17 miles , which corresponds to a depth increase of about 1,600 feet . To facilitate application of the data to engineering analyses , average characteristics are given for arbitrary north and south divisions of the 22 - mile - long producing area . The downdip increase of saturation pressure is taken as evidence of updip diffusion of solution gas from a somewhat higher concentration at the bottom of the reservoir . This effect is opposite to that previously observed in two prominent high- relief reservoirs in the Rocky Mountain area . The increasingly greater saturation pressures southward or downdip in the Greater Clareton area suggest a continuing migration of fluids into the structure .

Jan 1, 1964

By S. Banisi, A. Haji-Zadeh, H. Asadi, M. Maleki-Moghaddam

One area in AG/SAG milling field which has received a great attention is the optimization of liner design for any application to increase the availability of mills. The Gol-E-Gohar iron ore concentration plant uses three 9m × 2.05m autogenous mills (AG) in parallel in a dry operation. The AG mill shell is lined with three series (57 cm each) of 36-row liners. Due to large variations in feed characteristics and inadequate blending, the performance of AG mills has been lower than the target value. Therefore, to improve the comminution efficiency, the optimization of the design of AG mill shell liners was applied in this plant. By simulation it was found that increasing the liner lifter face angle from 7 to 30° while maintaining the original lifter height (i.e., 22.5 cm) could provide an appropriate charge trajectory. Measurement of the wear profiles of shell liners indicated that the wear along the liner length was not uniform and the highest wear occurred between 0.5 m and 1.2 m of the mill length. A new liner design was proposed by redistributing the metal from parts with a lower wear rate to the parts with a higher wear rate to arrive at a uniform wear profile along the liner length at the liner removal time. The non-uniform shell liner was constructed and installed in one of the three parallel dry AG mills. It was found that the first and second liner designs increased the mill throughput by 2.6 and 7.5%, respectively. After conversion to SAG milling on the account of liner change, 18% (from 413 to 489 t/h) increase in throughput was realized. It was predicted that the non-uniform liner designs will increase the liner life time by 10% and will reduce the scrap metal from the current value of 59% to 50%.

Jan 1, 2014

By P. Lenegan, R. Masethe, R. I. L. Ferreira

Underground mining in high rock-stress environments can induce unanticipated dynamic rockmass deformation, posing a serious risk to the workforce. Data collected by seismic networks are imperative for the design-as-you-mine process. Often an inappropriate assessment of the seismic hazard is done when unnecessary data are included in analytical techniques, particularly short-term time frames. Depending on the methodology or application of data analysis and interpretation, some of the information may not be relevant and even detract from the objective. By using the spatial event clusters associated with active workplaces to define the shape and size of the polygons for data selection for subsequent analysis, a problematic subjective component can be eliminated. The mining of tabular reefs in South Africa, be they gold- or platinum group metals, is very extensive, and underground workplaces are often widespread. Production stoppages are very costly, especially for marginal mines, so there is just cause not to evacuate an entire operation’s workforce following the occurrence of a large mining-induced seismic event. A rationale based on the damaging peak particle velocities (PPV) of the past seismicity can exclude the unaffected underground personnel and allow a quick orderly withdrawal where required. Micro-deformation may precede rockbursting, which can occur on-shift close to the workface. A mine-wide array of geophones suitable for the accurate location and analysis of seismicity may not be able to detect these higher-frequency emissions. Inexpensive but fit-for-purpose accelerometers, providing real-time, continuous measurement of acoustic rockmass deformation near the workplace, integrated through underground and surface communications networks, are shown to record ‘rock-talk’, clearly distinguishable from the instrument background noise, which can be in the order of hours leading up to an imminent damaging seismic event.

Jan 12, 2025

By M Carr, C Wheeler, M Lurie, B Chen

The demand for steel products in modern society is prompting the iron ore industry to optimise their operations to ensure sustainability of fines and lump products. One of the key components in the iron ore transportation chain are belt conveyors. The energy consumption of modern belt conveyor systems has reduced considerably over the past few decades, however, there is still significant scope for further reductions, especially when heavily loaded long overland belt conveyors are considered. A new rail based continuous bulk material transportation system has been developed by researchers at the University of Newcastle to reduce the energy consumption of heavily loaded and long overland conveyors. The Rail-Running Belt Conveyor technology is a state-of-the-art continuous belt conveying technology which provides an innovative and novel departure from conventional continuous bulk material transportation systems with significant energy and economic benefits. This paper presents an overview of a Rail-Running Belt Conveyor variant which considers an enclosed belt. Enclosed belt conveying has the benefits of encapsulating the bulk material, and thereby reducing dust emissions and moisture ingress, in addition to being able to negotiate smaller radius horizontal and vertical curves leading to greater flexibility. To quantify the primary differences between conventional conveying technologies, the Denver office of thyssenkrupp Industrial Solutions (USA) developed a case study for an 11 km long conveyor. The conveyor design throughput was 2750 t/h and included a small net elevation loss of 10 m. When considering CAPEX the Rail-Running Pipe Conveyor equipment supply cost is approximately 45 per cent of the cost of a conventional pipe conveyor, while savings upwards of US$50M emerge for CAPEX combined with five years of OPEX. The savings vary with the topography and density of the bulk commodity, with iron ore generally showing increased savings because the high bulk density increases rubber losses in conventional conveyors.

Nov 8, 2021

By S J. Chen, N Jiang, Y S. Ding, F X. Li, D W. Yin, F Wang

This study assessed the deformation failure characteristics of rock-coal composites with different height ratios. Uniaxial compression tests were conducted using an acoustic emission monitoring system and XTDIC three-dimensional full-field strain measurement system. The results showed that with the increase in rock-coal height ratios, the uniaxial compressive strength of composite samples increased from 5.26 MPa to 14.61 MPa. The evolution of the deformation localisation zone of the composite samples is closely related to the initiation and propagation of the primary cracks in the coal samples. At the moment when the main fracture of the coal samples occurs, there is a large drop after the peak of the stress-strain curve of the composite samples, and the height of the rock samples increased to varying degrees, which indicated that the failure of the coal samples induced the rebound deformation of the rock samples. With the increase in rock-coal height ratios, the rebound deformation amount of the rock samples decreased from 0.042 mm to 0.008 mm, and the rebound deformation rate decreased from 0.210 per cent to 0.010 per cent. Meanwhile, the rock samples’ rebound deformation releases part of the elastic energy to act on the coal sample, further contributing to the destruction of the coal samples. Compared with single composite coal samples, the coal samples of the composite samples have much more failures. In addition, with the increase in rock-coal height ratio, the input energy density, elastic energy density, post-peak release energy density, and residual elastic energy density of the composite samples increased, the dissipation energy density decreased, and the percentage of pre-peak elastic energy density increased from 98.56 per cent to 99.86 per cent. These results revealed the deformation failure characteristics of rock-coal composite with different height ratios and provided a theoretical reference for understanding the underground dynamic rock failures.

Nov 29, 2022

By T Trott, M Lewis, G Lumley

The analysis of equipment trends in The AusIMMÆs revision of Monograph 19 - Australasian Mining and Metallurgical Operating Practices (AMMOP) (in prep) in the paper by Graham Lumley raised some interesting, and in parts disturbing, trends in the Australian open cut mining industry. According to the Australian Bureau of Statistics (2011) the productivity of the whole mining industry is down by 34 per cent since 2001. In terms of open cut equipment, median output for draglines is down by 15 per cent since 2003, electric rope shovels are down by 41 per cent since 2003, hydraulic excavators are down by 39 per cent since 2008, front-end loaders are down by 39 per cent since 2007 and trucks are down by 41 per cent since 2006. Clearly e boom has not been good for the efficiency of the mines. During this same time, best practice (defined as the average of the top ten per cent by annual output per unit of input) has declined, but not by as much as the median (eg shovels down by eight per cent, excavators down by 19 per cent and FELs down by five per cent). This paper will build on the analysis of AMMOP to understand the differences occurring between median and best practice and identify the factors contributing to the decline in performance. As the industry enters a period of potentially lower prices for commodities and reduced margins, pressure will be brought to bear on mine sites to start moving more with the equipment they have. An understanding of where efficiency has been lost will be a key component in that. The information contained in AMMOP, and the subsequent analysis of that information in papers such as this one, will be crucial to reversing the decline in open cut equipment performance.CITATION:Lumley, G, Trott, T and Lewis, M, 2012. Reversing the trend in open pit mining equipment output, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 75-82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By Peter Riba

Up until ten years ago the industry had arrived at a relatively conventional, and consistent design of coke ovens. Through the years the designers and builders were not being heavily taxed to come up with revolutionary new designs. However, the stimulus for design change was ever present. These stimuli for change are quite important and they are the driving force which produce improvements. The most obvious stimulus to change a design is commercial. To "build a better mouse trap and the world will beat a path to your door" is the well used cliche which best befits this philosophy. As in all businesses, coke oven designs require that all of the considerations, which affect the cost or the desirability of the design, be optimized. One way to increase the desirability of the particular design, 1s to make the design in- expensive to operate. Or, put another way, to increase production for the same operating cost

Jan 1, 1980

By C. S. Harloff, Frank R. Corwin

THE Nichols Copper Co., associated with the Phelps Dodge Corp. and the Calumet & Arizona Mining Co., has constructed at El Paso, Tex., and is now operating a copper refinery with a yearly capacity of 100,000 tons of anodes. Transportation facilities were perhaps the most important of the considerations that led to the selection of this site. The rapid industrial development of the Middle and Far West has increased the consumption of copper there. The advantage of local refining as against shipping the copper to the Atlantic sea- board is apparent. Copper refined in the Southwest is equally competitive for export shipment, either from the Gulf or the Pacific Coast ports. The tonnage of copper produced in the Southwest not only justifies the construction of this plant, but may warrant considerable expansion in years to come.

Jan 1, 1930

By G. Fazel Jahromi

Enargite, known as one of the major arsenic containing copper minerals, with approximately 19% arsenic, introduces challenges to typical processing options. In most hydrometallurgical processing methods, arsenic remediation occurs after the copper recovery in an autoclave or in a stepwise neutralization process. In this study, the in situ precipitation of scorodite was investigated during an atmospheric leaching process in the presence of carbon-based catalysts and chloride media. The effective parameters of initial ferric addition, temperature, catalyst addition, and oxygen sparging rate were studied and the ferric behaviour was monitored during the scorodite precipitation. The most influential parameters on efficient scorodite precipitation are found to be: initial ferric addition, catalyst to concentrate ratio, and temperature. A 99% scorodite precipitation yield was achieved in this process.