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By M. Leva

WITH the development of new processes for the production of synthetic liquid fuels, an extensive literature search was undertaken to uncover fundamental relationships between fluid and heat flows and the operating variables of new types of converters. Examination of published correlations revealed that considerable uncertainty existed in the correlation of the operating variables of such equipment with the pressure drops which could be expected through packed and fluidized systems; correlations proposed in the literature differed from each other frequently by as much as 75 to 100 percent. Because new processes, especially more recent modifications of the original Fischer-Tropsch process, must compete with old, firmly established processes on the basis of unit product cost, the pressure-drop correlations in the literature were considered to be too inaccurate for use in calculating the energy required to pass fluids through packed beds. The following study was begun in 1946 to develop correlations that would be suitable for the design of new equipment in which fluids are brought into contact with granular materials. To arrive at general relationships, systems were chosen that did not involve chemical reactions, and a, particular effort was made to give the correlations only in terms of quantities that are ordinarily available from general process and design specifications.

Jan 1, 1951

Geochemical data on Australian granites and pegmatites, and the mineral components of these rocks, are compared with that obtained in similar studies in the U.S.S.R. and elsewhere.The geochemical character of tin granites and the trace chemistry of their component minerals, particularly biotites, have some significance as ore guides in prospecting for tin.The primary geochemical dispersion of tin can be readily tested both in the laboratory and field by colourimetric methods, after volatilization with ammonium iodide, using modifications of the method described by Wood (1958).Secondary dispersions of tin in residual soils or alluvia can likewise be readly tested by rapid colourimetric methods in the field, but simple hydraulic methods, handling larger sample volumes, give reliable outlines of dispersion patterns.INTRODUCTIONThe search for tin ores, whether lode or placer in type, is usually directed on genetic grounds to country within or adjoining acid intrusives.A long established means of prospecting is to test samples for cassiterite by panning or other hydraulic separation.These methods can be used on crushed lode material or the natural materials from placers.With the advent of new techniques for extraction and for colourimetric analysis for tin (Wood, 1958 and Ross and White, 1961) a means is available for rapid analysis of materials not susceptible to quantitative testing by hydraulic methods because of the fine sizings of cassiterite or the occurrence of tin structurally held in minerals. The new methods thus opened up the field of tin prospecting by extending the search for ore guides to genetically associated rocks and minerals, wall ror-ks of veins and a wider range of superficial deposits.

Jan 1, 1963

By Martti Hagfors

UNDERWATER EXPLOSIONS - Part 6 - EFFCTS OF CYLINDERICAL SHAPE OF CHARGE TO THE RESULTS OF ENERGY MEASUREMENTS OF EXPLOSIVES

Jan 1, 2008

By Les Gutzwiller

Fan applications in the mining industry have changed during the last 70 years. In 1922, J.R. Robinson authored a technical volume entitled Practical Mine Ventilation. At that time, atmospheric control had only recently shifted from natural to mechanical. The large, mechanical draft fans that were used then were centrifugal. The fans ran at low speeds, about300 rpm. Most were steam-engine driven. In the late 1920s and early 1930s, mines became larger, increasing the pressure and volume requirements of the fan equipment. Axial fans were designed to run at much higher speeds (710 to 880 rpm) and were driven by electric motors. They were also smaller and less expensive to install than the cumbersome centrifugal units. However, changes in mining have resulted in progressively higher static-pressure requirements. So centrifugal fans are once again proving to be a good choice.

Jan 1, 1999

By Jon R. Maki

"EVTAC, an iron ore mine in Minnesota, had trouble meeting the customer’s pellet silica requirements. In addition, the mine plan was moving towards a lower grade ore and funding was not available for plant improvements to compensate for the change in ore or improving quality. Small changes to optimize various processing equipment resulted in significant improvements in both quality and productivity; for example, productivity on one mill line increased by 10% while producing lower silica concentrate. This paper will provide the methodology that allowed EVTAC to improve quality and productivity through process optimization with little capital investment.INTRODUCTION EVTAC, an iron ore mine in Minnesota, had trouble meeting the customer pellet silica requirements. In addition, the short-term mine plan was changing to a lower ore grade. Because of limited funds, EVTAC did not have the capital for investing in the plant to compensate for the ore change or to make improvements to lower product silica levels. Small changes to optimize process equipment resulted in significant improvements in quality and productivity; for example, one mill line feed rates increased by 10% while also producing a higher quality concentrate. These changes were sufficient enough to allow the mine to lower the target ore grade beyond their initial goal. At one time, a $3M flotation facility was considered as a way to meet quality with the new ore grade. However, the process changes were able to accomplish the same silica reduction with roughly a $50,000 investment in VFDs for sump controls. This paper will discuss some of the modifications that allowed EVTAC to meet the quality and production objectives with little capital investment. It also discusses the methodology used to make these process improvements."

Jan 1, 2014

By F. B. Samani, B. Stabel

The 1,000 MW Hydro Power Station Masjed-e-Soleiman (formerly called Godar-e-Landar) in Iran is under construction since 1992. The rock engineering aspects of the major underground structure, i.e. the powerhouse cavern shall be reported on in detail. The geotechnical investigations are described and results given. The results of several geotechnical analyses are presented. The designed and executed rock support is given. A description of the monitoring systems and typical measurement results obtained during and after excavation are presented. The lessons learnt during construction of the Stage-I powerhouse cavern were applied on the extension of the powerhouse cavern, which is to house an additional 1000 MW. Details regarding the unexpected behaviour of the Mudstones are given. Die 1000 MW Wasserkraftanlage Masjed-e-Soleiman (vormals Godar-e-Landar genannt) befindet sich seit 1992 in Bau. Dieser Artikel berichtet im Detail über die felsbaulichen Aspekte der Untertagebauwerke, insb. der Maschinenkaverne. Die geotechnischen Untersuchungen werden beschrieben und deren Ergebnisse wie die Ergebnisse verschiedener Berechnungen werden präsentiert. Die geplante und die ausgeführte Felssicherung wird angegeben. Die eingebauten Überwachungseinrichtungen werden beschrieben und typische Ergebnisse während des Aushubs und danach werden dargestellt. Die Erfahrungen beim Aushub der Kaverne der Stufe I wurden beim Entwurf der Kaverne der Erweiterungsstufe II, die weitere 1000 MW beherbergen wird, berücksichtigt. Details zum unerwarteten Verhalten des Schluff-/Tonsteins werden angegeben. La centrale hydroélectrique de Masjed-e-Soleiman (dénommée anciennement Godar-e-Landar), d’une puissance de 1.000 MW, est en construction depuis 1992. Un rapport détaillé sera présenté sur les aspects relatifs à la construction en enrochements de l’aménagement souterrain principal, à savoir la caverne abritant la salle des machines. Une description des investigations géotechniques réalisées y est fournie ainsi que les résultats correspondants. En outre sont présentés les résultats de plusieurs analyses géotechniques. L’ancrage dans la roche tel que projeté et réalisé est présenté. Une description des systèmes de contrôle ainsi que les résultats de mesures typiques obtenus au cours des travaux d’excavation sont donnés. Les leçons tirées lors de la construction de la Phase 1 de la caverne de la salle des machines furent appliquées à l’extension de la caverne de la salle des machines, qui doit abriter une unité supplémentaire d’une puissance de 1.000 MW. Par ailleurs, des détails sont donnés sur le comportement inattendu des argilites.

Jan 1, 2003

By John E. Conley

The need for lightweight aggregate for use in concrete products ,and structures has caused the Bureau of Mines to undertake an investigation to determine the availability of suitable raw materials and to study methods, procedures, and equipment to supply that need. Evidence is at hand to prove that the shortage of lightweight aggregate is nationwide. A survey recently covered in a report (13)5/ by the Construction Branch of the National Housing Agency has pointed out the locations in which lightweight aggregates are produced. A study of this information discloses that the producing centers are widespread, and that certain areas, notably the region east of the Mississippi River, and especially the sections along the Atlantic coast line and the Southeastern States, have only a few such plants. Certainly, many localities are badly in need of installations equipped to provide an ample supply of high-grade lightweight aggregate. The work undertaken by the Bureau of Mines includes investigation of the use of clays, shales, slate wastes, coal-mine wastes, diatomite-clay combinations, and various other 'mineral mixtures as possible raw materials. Likewise, special consideration has been given to the development' of equipment and techniques to produce the lightweight products.

Jan 1, 1949

By Neo Molelekeng, Jocelyn Bouchard, Rebecca Monnapula, Martin Émond

"Xstrata Alloys – Eland Platinum concentrator (South Africa) has recently been commissioned and is now initiating a challenging optimisation program encompassing the entire operation. Process control improvements are key elements of the program and initial results have demonstrated how leveraging from current assets can bring significant improvements through overall reduction of variability. This paper gives a brief overview of the operations and details how Eland is striving to become a top tier leader with advanced regulatory control strategies recently implemented. Results reveal that what can be achieved in a standard control system (PLC or DCS) should not be underestimated as the first interventions led to a steadier operation of the primary ball mill circuit. Following the improvements, significant and sustained reductions of standard variation were observed for key process variables around their set-point: primary ball mill feed rate (72 %), rougher feed density (58 %), and rougher feed flow rate (47 %). A path forward has been identified to tackle further opportunities around the primary grinding circuit: water balance management, throughput optimisation as well as charge and power draw control.INTRODUCTIONThere are numerous approaches to mineral processing plant optimisation. As the benefits of determining the right reagent types, mix, dosage and addition points, or the proper charge of grinding media in a mill are fully appreciated, there is still nowadays some misunderstanding and misconceptions about process control in general and how it can contribute to the whole optimisation process. The confusion between the various disciplines involved, i.e. instrumentation, control system programming, automation and process control, certainly does not serve the best interest of the industry with this regard."

Jan 1, 2010

By G. B. Shea

Among the many engineering problems directly related to conservation in the petroleum industry, that of crude-oil emulsions continues to be important. Emulsions of water and oil always have constituted one of the most serious forms of waste in the oil fields, and the necessity of dehydrating emulsified crude petroleum to obtain marketable or pipe-line oil confronts operators in many fields with a major operating problem. In 1926 the Bureau of Mines published a comprehensive treatise s on oil-field emulsions dealing with field conditions, practical methods of dehydration, and physicochemical characteristics of the formation and resolution of emulsions. Although this bulletin is still available and may be obtained from the Superintendent of Documents, Washington, D. C., and although its contents are a valuable reference on the subject of emulsions, knowledge regarding the physical properties of emulsions and the phenomena of dehydration has increased greatly within the last decade. With the information gained through continued scientific research, substantial improvements have been made in the art of resolving petroleum emulsions. Moreover, in recent years there has been a growing realization of the importance of emulsion-preventive measures that has led to more critical examination of the causes of emulsions and methods of eliminating or at least reducing the degree of emulsification. Conditions causing agitation and commingling of oil and water and the formation of "cut oil" often are within the control of the producer, thereby making it possible to utilize preventive or remedial measures by which emulsification may be minimized or avoided. In fact, many companies have materially reduced their treating costs as a result of careful studies in emulsion prevention and proper handling of "wet" production. Of course, in many instances preventive measures or the correction of conditions causing emulsification cannot be achieved practically or economically, and the emulsions that form must be treated regardless of the care exercised or the money spent in attempting to prevent their formation.

Jan 1, 1939

By W. G. Pariseau

Reliable stress measurement using hollow inclusion gauges and monitoring stress change using borehole stress meters and borehole deformation gauges in anisotropic rock remains a challenge for the rock mechanics community. In this regard, the complex variable method advanced in 1983 for deducing stress in anisotropic rock is flawed and software is privileged. Fortunately, advances in computer hardware and software now enable fast, reliable reduction of hollow inclusion stress measurement data for determining stress in anisotropic rock. Monitoring stress change in anisotropic rock poses a different challenge but is also subject to numerical analysis. Stress measurement using a hollow inclusion (HI) gauge such as the triaxial Australian HI is done in four steps: 1) drilling a measurement hole, 2) installation of an HI, 3) stress relief of the HI by overcoring, and 4) data reduction. The last step, data reduction, is the focus of this work. The process is well-known in linearly elastic, isotropic rock (Worotniki and Walton 1976, Duncan Fama and Pender 1980). However, in case of linearly elastic, anisotropic rock the requisite technology is not readily available. This situation is somewhat surprising because anisotropy is more often the rule rather than the exception, especially in the neighborhood of ore bodies. Rahn (1984) has pointed out the potential for significant errors with neglect of anisotropy and the adverse consequences for engineering design. Amadei (1984) has also pointed out the potential for errors with neglect of anisotropic rock properties in stress measurement. Worotniki (1993) cites other studies that indicate potential for serious errors when doing measurements in anisotropic rock. In both theoretical cases (isotropy and anisotropy), data reduction is essentially a composite of solutions to boundary value problems in linear elasticity. In the finite element approach, the analysis is a simulation of gauge hole drilling, installation and overcoring. Two important advantages with the finite element approach are a more faithful representation of the conditions of HI stress measurement than approximated in theory and the capability for handling rock whether isotropic, transversely isotropic or fully anisotropic

Mar 2, 2022

By J. N. Van der Merwe

"A major shortcoming of the statistical back-analysis of coal pillar strength is that it relies on the asmined pillar dimensions, not taking into account time-related pillar scaling with subsequent reduction in pillar width. The paper describes an investigation where the rate of pillar scaling was applied to the pillars in the databases of failed and unfailed pillars. The reduced pillar sizes were then used in the same method of statistical back-analysis that had been used in the past.This resulted in an equation for pillar strength which predicts significantly greater pillar strength than the previous statistical analyses, which is similar to the strength which had been found earlier by direct testing of large specimens underground. It is concluded that the lower strengths found by previous statistical analyses are due to the incorrect pillar width being used and that by adjusting the pillar sizes to compensate for scaling, more credible results that correspond to direct testing are obtained.As the newly derived strength equation is time-dependent, it follows that the safety factors and probabilities of failure are likewise time-dependant. An equation to determine the probability of failure is also developed. This results in the safety factor being close to unity at a probability of failure of 50%, which is aligned to statistical expectation. IntroductionSince the Coalbrook mine disaster, caused by massive pillar collapse, there have been several attempts at analysing and defining the strength of coal pillars. It was realized in the very beginning that performing classical strength tests on coal specimens in a laboratory and then transferring those results to real coal pillars could not be successful. The scatter of results is one problem and, more seriously, there is a size effect (at least for small specimens) that made the transformation of strength results to much larger coal pillars underground all but impossible.Two main schools of thought then emerged. Some researchers preferred to perform direct strength tests on large specimens underground, while others relied on statistical back-analysis of failed and unfailed pillar cases, attempting to determine the differences in size and shape that would allow a satisfactory prediction of failure. The latter school of thought resulted in the method that was widely accepted by the South African coal mining industry, described in the landmark publication by Salamon and Munro (1967)."

Jul 1, 2019

The problem of separating the constituents of a mixed gas has assumed increasing importance to chemical technology during the last several decades. Metallurgical practice, dealing mostly with the application of gases as fuel, such as for the oxidation or reduction of ores, has not often confronted an important need for such separations. If theory occasionally has indicated advantages in the use of purified or separated gases, as for example the "dry" blast for the iron furnace or oxygen-enriched blast for a variety of smelting operations, the economics of the proposals has not often been satisfactory. It has seemed evident that the practice of the chemical plant was too expensive with regard to installation or material costs, or both, for the needs of the basic smelting industries and indeed was applicable commercially to metallurgical purposes only when the metals in question were especially valuable or pure. This bulletin deals with a new mechanical means of attacking the problem of separation. Although it is improbable that any one type of separation could hope to find universal application, the method described is to be regarded as an alternative to conventional means that has attractive possibilities in certain instances. It extends the number of methods previously available by one that has not before been applied commercially and that utilizes a well-known property of gases that never has received effective technologic attention.

Jan 1, 1940

By Y Öztas, S McKinley, T Baker

The Kisladag Mine, Turkey, is a large porphyry gold deposit which is mined by open pit methods. In operation for over ten years, Kisladag provides an excellent example of how attention to a geologic feature, namely hydrothermal alteration, became a very effective predictive geological tool for planning and operation. The alteration domains were initially used as a geological tool to assist with establishment of resource model domains and to guide delineation drilling, but they were soon recognised to be correlative to geotechnical characteristics (affecting pit slope angles) and metallurgical performance (heap leach recoveries). Recent developments in spectral processing allow the systematic quantification of complex overlapping alteration phases and have greatly improved the ability to rapidly define internally consistent alteration domains for geotechnical and geometallurgical purposes.Alteration at Kisladag comprises a central core potassic (K-feldspar-biotite) zone, a tourmaline-white mica enveloping zone, an advanced argillic lithocap on the deposit’s eastern side and an overprinting pervasive argillic zone. These alteration zones and their distribution were based initially on strictly qualitative, visual mineralogical logging of diamond drill core. With the need for more accurate and consistent identification of the alteration mineral suites, particularly the phyllosilicate phases, logging was augmented by systematic measurement of spectral data using a Terraspec instrument.Recently the Kisladag spectral database (over 85 000 readings) was reprocessed by the newly developed methodology (aiSIRIS™) that allows relative quantification of the spectrally-responsive minerals. Visualising this transformed spectral mineralogy at various mineral concentration thresholds using implicit modelling software (Leapfrog®) led to the creation of consistent mineralogical and alteration domains that are used for the definition of geotechnical and geometallurgical parameters. An implicit modelling workflow enables these domains to be easily updated as new data is collected while maintaining geological integrity of the model.CITATION:McKinley, S, Baker, T and Öztas, Y, 2017. Alteration at Kisladag gold mine, Turkey – a progressive study in geology, geotechnics and geometallurgy, in Proceedings Tenth International Mining Geology Conference 2017, pp 51–62 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By Huw Williams

It is becoming increasingly common practice to re-use existing foundations for new projects, especially on urban sites where geotechnical conditions are congested. A knowledge of the foundation dimensions and capacity is essential for this to take place, however, as-built records are often non-existent. Non-Destructive evaluation (NDE) is now becoming an important tool in assessing old foundation properties and their potential for re-use. Pile dimensions are also critical in the power industry, when they are supporting transmission towers which need to be upgraded, and may carry additional wind loading. This paper describes the application of various NDE techniques that are available and how they can be used to determine pile length, shape and capacity in difficult site conditions, including foundations under structures.

Jan 1, 2006

By Martin J. Pedley

The use of soil nailing has grown steadily in the UK over the last 15 years and it has recently become more popular in the Republic of Ireland. This paper presents three soil nailing temporary works case histories where the technique has been used to support steep excavations in difficult ground conditions. It demonstrates the effectiveness of soil nailing when applied in appropriate conditions. Details of design methods and construction techniques are described and those aspects of soil nailing that will benefit from further study and development are identified.

Jan 1, 2000

For the first time in its history, the George A. Fox Conference let its focus venture away from the friendly confines of the East Coast of the United States to spend part of the one-day conference looking at projects from around the globe. With a record-setting attendance of 377 people, the conference, titled ?Tunneling: An international perspective,? opened with a keynote speech from special guest In-Mo Lee, professor, Korea University in Seoul, South Korea. He is also the president of the ITA-AITES. In a sweeping presentation, Lee walked the packed audience through some of the most fascinating and challenging projects in his home country. Among the projects he spoke about were Korea?s longest railway tunnel, the Solahn Tunnel and the Inje Tunnel, a freeway tunnel that is 11.94 km (7.4 miles) long.

Jan 1, 2012

By Max F. Lee, Warren A. Peck

The applicability of the Q-system [Barton et al. 1974] to Australian underground metal mines is discussed with reference to two common design issues: ground support for horizontal mine development, and assessing the stability of bored raises. Installed ground support in mine development is com-pared to empirical estimates using the Q-system and associated support capacity calculations. Data are graphically presented from 59 specially selected sites at 15 contributing mines. The actual performance of large-diameter raise-bored shafts is also compared to empirical stability assessments using a modified version of Q (Qr, after McCracken and Stacey [1989]). Lower-bound Qr values are plotted against raise diameter for 47 selected sites at 23 mines in Australia and Papua New Guinea. The influence on Q and Qr of some geotechnical aspects of the Australian landscape, the dynamic nature of mines (compared to civil construction), and occupational health and safety regulations are discussed. Stability and support assessments that are based just on Q or Qr are not always conclusive. It is often necessary to consider other rock mass parameters, the regulatory environment, and risk issues. These results are interim; further data collection and analysis are required with regard to comparing actual performance versus empirical assessments.

Jan 5, 2007

This paper describes a mobile laboratory developed specifically for nickel prospecting, and which was designed to be operated by sub-professional staff in remote areas independently of established laboratories. An atomic absorption spectrophotometric procedure was used to determine nickel, cobalt, lead, zinc, and copper ID latentIc and sulphIde samples, with a detection limit better than 25 µg/g for all elements. The procedure was applicable to both soil and drill samples and the accuracy of the procedure, which was ±5 per cent relative at the 1,000 µg/g level was sufficient for the preliminary assessment of mineralized samples and the control of drilling operations. The analytical procedure and the means taken to ensure the necessary reproductibility and accuracy are described. One operator can carry out 400 elemental determinations per 8-hr day at an approximate cdst of 6 cents per elemental determination. The results are returned within a single day, a factor which can contribute materially to the efficiency of drilling operations.

Jan 1, 1970

This briefing was sponsored by the Bureau of Mines to summarize ongoing and recently completed chromium-chromite research and resource assessment activities by the Bureau. Through the series of 18 presentations compiled herein, Bureau personnel covered a wide range of topics including U.S. chromite and chromium trends and usage patterns; foreign and domestic resources; and research activities on mineral characterization and beneficiation, chemical and pryometallurgical processing of chromite and chromium-bearing wastes, new low-chromium alloy and coating substitutes, corrosion- and oxidation-resistant stainless steels, and chromium-containing refractories.

Jan 1, 1986

By J M. Fletcher

The responsibility and scope of the Industrial Engineering Department, as organized at the Jeffrey mine, has been broadened to include any study, project or report that could result in more effective use of men, materials and equipment. Although still emphasizing wage incentives and co t reduction, much more varied work is now done, consistent with the in-.creased complexity of industry. Additional activities now include production, maintenance and inventory control improved job evaluation, packaging, labour utilization studies, technical sales liaison, mining, milling and service department n1ethods, plant layout, and specialized project analysis. Additional techniques include the extensive use of work .sampling and standard data. A recent trend has been toward increased emphasis on industrial relations, both in introducing change to the men and in providing requested explanations to Union stewards and officers. These new responsibilities have resulted in the development of specialists in some rather narrow industrial engineering fields, as well as the necessity for industrial engineering assistance in supervisory and job training.

Jan 1, 1963