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Traditional in situ fan flow test methods under accepted standards require determinations to be made of both static pressures and total pressures during testing. This is to determine the resultant velocity pressures, which are vital in the accurate determination of the final fan airflow. These crucial velocity pressure (Vp) determinations are normally determined using simple manometric instrumentation such as an electronic manometer or an inclined liquid filled manometer. There is relatively little noise or fluctuation in the static pressure determinations and they can be quite easily and accurately recorded. There is almost always considerable fluctuation in the velocity pressure determinations though due to the highly turbulent and irregular velocity profile normally found in such in situ installations. This velocity turbulence means that the recording of such data is subject to random human error as the observer tries to average such fluctuations mentally during the observation period. Worse than this, and in the extreme, the recording of such velocity pressure data could actually easily be misreported if, for some reason, persons chose to do so.The author has devised a field method using highly accurate quartz crystal logging barometers to objectively record these velocity pressures. The method eliminates the ability to either mistakenly or intentionally misreport these crucial velocity pressures and is carried out in parallel with the recognised methodology, so result comparisons can be drawn. As such, a far greater level of confidence can be achieved in the final flow performance results than using the traditional more subjective method. Further to this it is difficult and almost impossible to refute the results using this ancillary substantiation method.The accurate determination of fan flows due to the impost of the carbon tax has taken on much more significance given the financial impacts in Australia at this time. The methodology detailed herein can be applied equally for both fan flow compliance testing and the verification of mine airflow data for greenhouse gas emission evaluations.The paper utilises the results of one 24-point pitot traverse to demonstrate the various findings. These include the very wide range of velocity pressures, which were logged at most of the measuring stations. It also illustrates how the method is utilised and compares the results derived from both this method and the more subjective traditional method along with the benefits of logging the velocity pressure results during the testing process.CITATION:Rowland, J A, 2013. Removing some subjectivity from traditional BS 848 and ISO 5802 in situ fan flow tests, in Proceedings The Australian Mine Ventilation Conference , pp 155-162 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By P. Tracy

An advanced real-time monitoring system, called a "Tapblock Diagnostic System" is under development to help furnace operators manage the operation and maintenance of their tapblocks. The life of a water-cooled tap block in a smelting furnace ranges from several months to several years, depending on the operating conditions. Tapblocks are typically replaced at regular maintenance intervals; a strategy based largely on historical records and not on the actual condition of a particular tapblock. The Tapblock Diagnostic System monitors the tapblock throughout its life and accumulates probable wear events to help the operator assess the residual integrity of the tapblock. Benefits of this system include the ability to provide early warnings of tap block wear to provide improved safety and maintenance planning. Using cooling-water flow together with copper and water temperature measurements, the system performs calculations that compare the present tapblock performance with the expected operating envelope using a multivariate statistical method (Principle Component Analysis). The operating envelope is pre-calculated for a wide range of operating conditions using transient thermal modeling (Computational Fluid Dynamics). A state indicator in the form of a green, yellow and red light is used to inform operators of the tapblock performance and health status.

Jan 1, 2007

By Herman W. Hill

This report summarizes research into the root causes of failures in mine power systems which impact safety and reliability. Abnormally low fault currents, due to arcing faults, self-excited systems, and fallen trolley wires are examined and quantified. The reliability of components which are critical for safety is studied, as well as reliability of components which are crucial to the mining pro cess. Failure rates are found through in-situ tests, accelerated life tests, studies of mine maintenance, and fault-tree analysis. Reliability data is used to predict fatalities and lost-time accidents through computer-aided fault-tree analysis. Analytical support tasks reported include the deriving of trailing-cable ampacities under cyclic loading, and the measurement of connected ground beds.

Jan 1, 1981

By David J. Hoadley

This report describes the development and limited testing of a semi-automatic, raise climber, Compact Service Hoist System designed for stope access in underground metal and nonmetal mines. Demonstrated capabilities of the system include a 1,000-lb payload capacity, control from the traveling cage and from up to three remote stations, operating in vertical or inclined raises 3 ft in diameter and up to 300 ft in length and a travel speed of 50 ft/min. The system has the capability of operating in crooked raises because the conveyance climbs two stationary wire ropes suspended down the raise. The drive unit is electrically powered with power and control signals supplied to the drive unit through an umbilical 'cable also suspended down the raise. The system has been designed for portability, ease of installation and minimum raise development. The hoist has been demonstrated successfully in an above ground test tower. This report provides a detailed description of the hoist design and its demonstrated performance to date.

Jan 1, 1985

By D. J. Charlton

"IntroductionMaintenance is a business, which to be successful, requires good management, systems and reporting. The prime objective of the maintenance management group, be they large or small, must be to anticipate and prevent interruptions in operations by keeping equipment in good mechanical condition. This objective should be carried out at minimum cost consistent with maximum productiveness.The objective of this chapter is to give an insight into the various aspects of maintenance management that must be considered to effectively and efficiently operate a mill complex. The degree to which the maintenance sub-systems are developed in an operating mill will be determined by the size of the mill and the needs of the operation.The criterion of the management system used is that the system serve the operation and not vice versa. The systems presented should be considered as tools and, as with all tools, they must be sharpened and replaced as the need arises or as more effective tools become available.To understand what is involved in maintenance management, it is worthwhile to consider a systems approach to analyzing management problems. This approach was developed by J.A.B. Rae while reviewing maintenance management systems for Cominco Ltd.A very simple system involving managing results and objectives is shown diagrammatically in Figure 1.The systems approach to organizational development involves four basic elements: an objective, a result, an activity and feedback. In the analysis, the activity element is broken down into individual actions that people could be held responsible for. If we introduce the action of operating into the diagram of Figure l, we arrive diagrammatically in Figure 2."

Jan 1, 1989

By Ralph H. Whaite

To assist the anthracite industry obtain technical data on pneumatic packing, the Federal Bureau of Mines imported a pneumatic packing machine from Germany and installed it in a mine of a cooperating company in the Northern anthracite field of Pennsylvania. This report covers the second in a series of experiments in applying pneumatic packing for controlling strata movement (subsidence) above mine workings in the Pennsylvania anthracite region. The first experiment2/ was begun in January 1950, in a section of the mine where about 50 percent of the original coal remained in the form of pillars; since the company did not plan to mine the pillars in this particular area, pneumatic packing of the chamber voids was done for test purposes only. During this initial test the machine was operated on 204 shifts, and 652,400 cubic feet of breaker refuse material (22,834 tons) was packed into the voids of 16 chambers. The work was completed in December 1951.

Jan 1, 1956

By Cleber Caetano Thomazi

Rotary kilns are continuous process equipment used on calcining of nickel ore. The chemical and physical reactions are created by means of heat up the material to predetermined temperatures. Tertiary air fans are attached to the kiln shell to maintain oxidizing/reduction conditions. Special ducts orientate the air flow inside the kiln. In the present work, two types of failure on distinct tertiary ducts mounted on the same kiln are reported. Chemical analysis, hardness test, metallographic and fractographic examinations were carried out. Fabrication related problems and creep were identified as the root causes of damages.

Oct 30, 2017

By T M. Nester, D J. Reardon, A N. Page, B J. Barsanti

The load capacity of a friction bolt has long been regarded as 4 t/m of embedment for ground support design analysis and supported by in situ pull test results. In recent years, the authors have observed lower pull test results or inconsistent results which were rarely sighted in the early 2000s. The lower pull test results indicated in some cases that reliable friction bolt capacity (≥90 per cent of results) is closer to 3 t/m of embedment with some geotechnical engineers adjusting the ground support parameters in the design work accordingly. This can be in contrast with other mines which reliably obtain 4 t/m (or greater) using the same suppliers bolt in similar ground conditions. This raised several questions: • What is the effect of poor installation (bolt twist or bolt hole deviation)? • Does the performance of friction bolts vary in different rock masses? • Does bolt performance vary between suppliers? • What effect does increased jumbo feed/percussion/rotation settings have? • Have the bolt dimensions or steel strip width changed? • Have the physical bolt properties changed? • Have the steel properties changed? This paper was aimed to answer as many of these questions as possible and discuss each variable in detail. This project included friction bolt trials at various mine sites across Australia, multiple friction bolt manufacturers, steel manufacturers and laboratory analysis. The paper also includes discussion on what the authors consider best practice for pull testing. It should be noted, the terms ‘friction stabiliser’ and ‘split set’ used in this paper are used in a generic manner and is not linked to any specific ground support supplier. Whilst its acknowledged within the industry the term split set and friction stabiliser is used interchangeably, the authors acknowledge that the term split set is a trademark of Split Set Mining Systems and has been used in context in this paper.

Nov 29, 2022

By R McDonough

DTL2 contract C916 was awarded in March 2009 for S$340 M. This contract includes two mass rapid transit (MRT) 1100?m long bored tunnels using two slurry tunnel boring machines (TBMs), with an internal diameter of 5.8?m, two cross passages and 135?m of cut-and-cover tunnels The contract also includes the design and construction of a new underground station including station entrances, subway links, architectural finishes and external landscaping. The station, located at Upper Bukit Timah Road near Jalan Jurong Kechil will also double as a civil defence shelter.The works included significant traffic management in a dense urban area in order to create the working areas whilst keeping the requisite number of traffic lanes. This involved numerous utility diversions and included the removal of a 33-year-old pedestrian overhead bridge (POB) over busy Bukit Timah Road. The station and tunnelling works were completed on time, including a ‘dock and dismantle’ TBM retrieval and subsequent breakthrough of the separating wall.This paper will detail the methods and solutions used to construct the tunnels and stations, with a focus on the requirements for construction of the station to be a civil defence shelter if required. This involved solutions to tying reinforcement and placing concrete to high standards in a restricted space, as well as the incorporation of heavy blast doors and other associated protective measures. The efforts of the management team resulted in the project being awarded first prize in the 2011 Land Transport Authority’s Annual Safety Award Convention and being named winner of the Safety and Health Award Recognition for Projects (SHARP) award at the 2011 Workplace Safety and Health (WSH) Awards. As well, McConnell Dowell won a Green and Gracious Builder Award (Excellent Category) from the Building and Construction Authority (BCA).CITATION:McDonough, R, 2014. Design and construction contract C916 Beauty World Station and Tunnels, Singapore, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 411–418 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By J. M. Rios

This paper exposes the reasons that led the Empresa Nacional Minera del Sahara, S.A. (ENMINSA) to the selection of a conveyor belt system for the transport of phosphate rock over a distance of 100 kilometers. ENMINSA was created in 1962, with the main objetive of the exploitation of phosphate rock deposits in the Spanish province of Sahara, in North West Africa. Poor grade outcrops were known previously. A detailed geological research carried over the province led ENMINSA to the discovery of deposits not exposed, and of much higher grade. The sector known as Bu-Craa was chosen as the most promising, and was explored by means of drill holing and shafting. The important amount of information obtained permitted a detailed evaluation of the capacity and grade of the rich ore contained in the Bu-Craa area. Simultaneously with the systematic reconnaissance of the Bu-Craa deposits, ENMINSA developped the study of the technical and economical problems required for the beneficiation of the rock, which comprised five main groups of projects: rock exploitation; beneficiation plant; rock transport from the mine site to the Atlantic coast; storage, handling and loading facilities by the sea- side, and power plant. Once determined the location of the marine loading facilities, which to date are in an advanced stage of construction (figs. 1 and 2), the studies conductive to the selection of the best transport system from the mine to the ocean, along 100 kms. distance were undertaken.

Jan 1, 1968

By B Robertson

Over the 40 years that the author has been engaged in the Australian underground coal mining industry, there has been a continuous improvement in safety performance as the sector has grown in size and productivity. The underground environment hosts many hazards with significant risk profiles that are kept in check by effective health and safety management systems that have evolved largely following major underground disasters. Observations are made on the changes observed for specific aspects of the underground coal sector, with particular reference to ventilation issues, and predications are made as to the needs of the future.CITATION:Robertson, B, 2013. Past achievements and future challenges in the underground coal sector, in Proceedings The Australian Mine Ventilation Conference , pp 27-32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By Chas. F. Jackson

The work of the Mining Division is divided among seven sections, each in charge of a supervising engineer, as follows: 1. Metal-mining methods section, the supervising engineer of which is also supervising engineer of the Southwest Experiment Station at Tucson, Ariz. 2. Metal-mining research section. 3. Nonmetal-mining section. 4. Coal-mining section. 5. Mine-ventilation section. 6. Mineral-industries survey section. 7. Electrical section. The names of the sections indicate broadly the fields covered by each, and in the following, pages the objectives and type of work of each section will be summarized briefly and their active problems listed. The work clone during the fiscal year 1937 will also be summarized.

Jan 1, 1937

By C. H. Hopper

DIAMOND drills have played an important part in the development of mines for many years. Recently. they have also entered the production field arid the use of diamond drills m the primary breaking of ores has become a big branch of the industry. The writer has estimated roughly that the total diamond drilling in Canada during 1942 was 5,625,000 feet, of which 2,250,000 feet, or 40 per cent, was for blast-holes. This accounts for 6,750,000 tons of ore broken, using the conservative factor of 3 tons per foot of hole. Many consider that the use of diamond drills for blast-holes is the most important advance in mine practice of the past decade, and the industry owes a great deal to the staff of Noranda Mines, Limited, for the pioneering they have done in the development of long-hole mining methods and for publishing their results. A great many mines have followed Noranda's lead. At the Waite-Amulet, Aldermac, Flin Flon, Canadian Malartic, Hoyle, and Matachewan Consolidated mines, most of the ore is broken by long-hole blasting. While the mines were developing new methods, the diamond-drill industry was developing mechanically-set bits and better machines. Through the effective use o smaller, cheaper diamonds, as well as more efficient setting, bit costs per foot are only one-half what they were ten years ago. Few people realize that a diamond bit is relatively inexpensive. The common EXT coring bit, for example, contains some 200 small diamonds, weighing altogether about 2.70 carats which, at $3.40 per carat, cost $9.20. After use, the equivalent of about 100 of these diamonds may be recovered. Therefore the true cost of the bit is only $7.00, made up of $4.60, the cost of the diamonds lost, $2.00 for setting, and $0.40 tax. The trend in machines has been toward specialization for the different classes of rock in blast-hole work. Light, high-speed machines have been developed for soft ores and higher powered machines for hard ores.

Jan 1, 1943

By Leijun Li, M. M. Mahapatra

"A three-dimensional finite element model with moving heat source was developed for pulsed-laser powder deposition (PLPD) process. Experiments were conducted to study the repair of superalloy components using the PLPD process. During the experiments, IN 625 powder was deposited on a superalloy substrate similar to IN 738. The process was modeled using three-dimensional finite element analysis. Element birth and death technique was used in the finite element model for simulating the deposition of powder layer on the substrate. A moving distributed heat source was used in the thermal model for realistic simulation of the process. Temperature dependent thermal material properties including enthalpy were used for the powder and the substrate in the transient thermal analyses. The fusion zones and peak temperature distributions of the deposits were predicted from the transient thermal analyses.IntroductionPoor weldability is a critical issue of superalloy repairing. The microstructural directionality of the superalloy components are disrupted when repaired by the fusion welding processes. Currently there is no widely accepted method to economically and reliably repair directionally solidified superalloys components. Pulsed laser powder deposition process (PLPD) is a promising repairing technique as the substrate is not severely affected by the heat source.In this study PLPD technology is used as the tool for superalloy repairing. In most of the land based turbine engines the directionally solidified nickel based superalloy similar to IN 738 [1] is used as the bucket material. The turbine engine blade tips are subjected to a combination of extreme operating conditions and corrosive environment. The tip of the nickel based turbine engine blades can be repaired using IN 625 material as suggested in the literature [1-2]. IN 625 is considered to be ductile and strong enough for the purpose of Ni based turbine engine blade tip repair[1-2]. During the present PLPD investigation, IN 625 powder was used as the deposit material on an experimental super alloy substrate similar to IN 738 superalloy used as the cast superalloy for the turbine engine blades."

Jan 1, 2012

By G. G. Campbell

The Bureau of Mines in cooperation with Quaker State Refining Corp. conducted two underground-combustion oil-recovery experiments in the Venango Second sandstone in the Reno pool, Foster-Rena-Oil City field, Sugar Creek Township) Venango County, Pa.) to determine the applicability of the process for reservoirs producing Pennsylvania-grade paraffin-base crude oil. Tests were terminated when analyses of produced gas showed that a self-sustaining combustion front did not exist. It was thought that insufficient fuel had been deposited in the formation. Laboratory retort tests made after the second field test was concluded showed that crude oil from the Reno area would deposit enough fuel to support combustion if air flux, temperature, and time were maintained within defined limits.

Jan 1, 1967

By R. G. Eggert

"A critical element, as the term has come to be used, provides essential properties to a modern engineered material and is subject to supply risk. The rare-earth elements became perhaps the most prominent of the critical elements in recent years because of their important uses in permanent magnets, advanced lighting, and military materials; the geographic concentration of production in China; and the dramatic run-up in prices in 2010-2011 followed by price collapse between 2011 and 2016. Yet criticality extends beyond the rare earths. What is critical depends on your perspective – who and where you are, and when you ask. This paper reviews the many perspectives on, or faces of, critical elements. It compares and contrasts perspectives of industry (General Electric), national or regional manufacturing sectors (Japan, European Union), emerging energy technologies (as seen by U.S. Department of Energy and, separately, Joint Research Centre of the European Commission) and the world as a whole (as evaluated by academics). This comparison reveals a diversity of not only perspectives but also methodologies and time frames of concern.INTRODUCTIONRare-earth elements appeared prominently in the news in 2010 and 2011 because of the dramatic increase in their prices; their important uses in permanent magnets, advanced lighting, and military materials combined with the geographic concentration of production in China, which reduced export quotas significantly. Rare earths became the most prominent of what have become known as critical elements or materials – that is, those that provide essential properties to modern engineered materials and yet are subject to supply risks.Yet criticality, the state of being both essential and subject to supply risks, extends beyond rare earths. What is critical depends on your perspective. This paper begins by reviewing a little history and presenting a general conceptual framework from which to think about critical materials. It then reviews the many perspectives on, or faces of, critical elements – corporate, national, and global, as well several that focus on emerging energy technologies. The paper concludes with thoughts on what to do to mitigate the potentially negative effects of the supply risks associated with criticality."

Jan 1, 2016

This paper firstly reviews the requirements for container and hopper design for reliable discharge. Discussion is then directed to the evaluation of the consolidation stresses acting in both in both the cylinder and hopper sections during both initial and flow conditions. Here the vast difference, especially in vicinity of the bin outlet, between the initial or filling and flow conditions is highlighted. This vast difference has major design and operation implications. A further major implication is that all bulk solids must dilate to flow. The opportunity to simultaneously attain reliable discharge and partial moisture removal is also examined.The selection of design parameters to maximise the consolidation stresses in both the cylindrical and hopper sections is detailed. In regard to the latter, it is recommended fine coal bins be discharged using low friction lined transition hoppers with large outlet spans. Such outlets will discharge fine coal in a relatively compacted state. This compaction state should exhibit minimum water retention and short term moisture uptake.

Jan 1, 1998

By C. G. Maier

Relatively infrequent use by metallurgists of the term "sponge chromium" as contrasted to more than occasional reference to "sponge iron" may be ascribed to the fact that the former material is not a commercial product, while the latter has been known and used, at least in one form (Swedish sponge iron), for several decades. It is doubtful whether a true sponge chromium ever has been prepared heretofore in the laboratory by more than one or two investigators. Nature presents a much. more difficult problem to the investigator endeavoring to make sponge chromium than pertains to the production of more easily reducible elements such as iron or nickel. Recent widespread interest among metallurgists in the possibilities of powder metallurgy is ample incentive to explore the feasibility of producing pure chromium metal in finely divided form. The shift in terminology of this statement from "sponge" to the "finely divided form" is deliberate in emphasis of distinction between terms that occasionally have been used loosely. It would seem desirable that a uniform usage descriptive of finely divided metals be adopted. While to some it might seem preferable that the terra "powdered" metal be reserved for a finely divided form produced by mechanical means, as, for example, chromium produced by the mechanical comminution of electrolytic sheets or flakes, current usage of the term "powder metallurgy' involves no distinction as to source type of material. It is usually accepted, however, that a sponge metal is one reduced from oxide or other combined form at temperatures below the melting point of metal or oxide so that the particles of metal are pseudomorphic, at least macroscopically, with the source material, and, in consequence of the loss of material without change of external shape of the particles necessarily have an open, porous, or "spongy" structure.

Jan 1, 1942

By André de Almeida Grilo

Correias transportadoras de alta temperatura são ativos críticos para a pelotização devido ao prejuízo que sua falha pode trazer para a produção. Nesse sentido, deve-se avaliar a vida útil da correia em uso, visando, principalmente, auxiliar sua manutenção, e nesse contexto o presente trabalho tem como proposta utilizar a caracterização dos componentes e o estudo da degradação térmica do material da cobertura de correias transportadoras de alta temperatura. As caracterizações foram realizadas de modo comparativo entre três tipos distintos de correias transportadoras de alta temperatura fornecidas para a VALE S.A. Os reforços das correias foram caracterizados por FT-IR para análise qualitativa do polímero. De maneira semelhante, as borrachas foram caracterizadas por meio da análise do produto de pirólise via FT-IR e a densidade de ligações cruzadas por meio da técnica de inchamento do polímero e aplicação da equação de Flory-Rhener, o que ajudou a justificar o comportamento das diferentes marcas de correia perante a degradação térmica, estudada em um trabalho anterior. A partir desses resultados e utilizando dados de variação das propriedades mecânicas do material em função do tempo e temperatura de processo, pôde-se avaliar a taxa de dano causado a cada correia e, aplicando-se dados reais de processo, avaliou-se o desempenho das correias em trabalho.

Aug 8, 2018

By D. F. Hambley

This manual contains a step-by-step procedure for the design of ore passes for open pit mines. The manual is comprehensive and deals with all aspects including location, design, construction and operating considerations. In the construction section, all applicable raising and shaft sinking methods are considered and cost estimates and advance rates provided for each. The design process is divided into several sections - rock flow requirements, support design, dump point design and draw point design. Use of this manual provides open pit planning engineers with a means of designing and assessing the feasibility of ore passes for their operations.

Jan 1, 1983