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By Martin D. Larisch, Ronald Damen

The design and construction of temporary working platforms for cranes and piling rigs is a high-risk activity. It requires the careful selection of the appropriate input parameters to obtain the correct load cases, as well as the application of robust and reliable design methods to assess the required thickness and stiffness of the working platform. The document introduces some of the most common and most relevant guidelines for working platform design which are currently used in Australia and New Zealand. The authors will also discuss the basic assumptions and considerations about load transfer from construction plant, debate ground risk, compare the applicability of different design methods for various ground conditions and suggest some common verification methods for working platform certification.

May 1, 2022

By Kermit Reins

The most recent modernization phase of the wire rod mill at Sterling Steel involved installation of a pre-finishing mill, using a Morgan Vee Mini-Block, a new water box and shear with utility systems and automation. The new mill configuration adds more stands to the mill for better drafting and is designed to improve finished product quality by providing a more uniform entry temperature, better control of the feed section into the No-Twist® mill as well as enhanced surface quality. The new shear improves cut length accuracy as well as decreases the amount of trimming to reduce yield loss. This paper explains the changes made in the mill and the features of the new equipment and automation.

Aug 17, 2017

By Henry N. Doyle

One can hardly discuss coal pneumoconiosis unless it is placed in the context of the total pneumoconiosis problem in the mining industry. However, it might be well if first we defined a few terms, since it has been my experience that the use of the word pneumoconiosis frequently causes con- fusion among those who are not familiar with the term. Pneumoconiosis comes from two Greek words meaning lung and dust. Hence, the word pneumoconiosis simply means dusty lung, or dust on the lung. There are many forms of the disease, some of which are disabling and some are not. Among the many dusts which cause pneumoconiosis might be included silica, asbestos, coal, talc, iron ore, and many other mineral dusts. Silicosis is a specific form of pneumoconiosis. It is caused by the inhalation of excessive amounts of silicon dioxide in the form of crystalline quartz. The disease is manifested by nodulation of the lungs which is apparent on an X-ray film. Continued exposure to silicon dioxide causes the nodules to grow and ultimately large areas of the lung become scar tissue which pre- vents the lung from performing its physiologic function. In its more advanced stages, there is a significant loss of pulmonary function which accounts for

Jan 1, 1966

By Ellis S. Hertzog

The data published in this retort cover only one phase of a special study of tile physical and chemical properties s of only Alabama coals made by the Bureau of Mines. In addition to determinations of friability, the survey included determinations of grindability, B.t.u. value, and ash-fusion temperature. Assay distillation tests, both for high- and low-temperature carbonization, and proximate and ultimate analyses were made also. However, this preliminary paper is concerned only with the results of friability tests and is issued to expedite the release of this information to the public. The friability, test measures the liability of a coal to break into smaller pieces when subjected to repeated handling, as occurs in the mining, preparation, and transportation operations. Friability depends on many physical characteristics of the coal that vary not only between different seams but also in the same seam. The laboratory methods of determining friability have been developed to give a practical means of estimating degradation of size. So far as is known to the authors, no data on the friability of Alabama coals have ever been published. This caper makes available for the first time fairly comprehensive3 information on this subject. Because the procedure for the tumbler test for determining the friability of coal is relatively new to the coal operators, the authors Lave included a, complete description of it in this report.

Jan 1, 1938

By W. G. Sandell, G. M. Potter

"As a part of the wartime activities of the Bureau of Mines, metallurgical services were extended to other Government agencies engaged in purchasing and stock-piling some of the more critical and strategic materirals. At the request of George A. Easley, representative of the MetalsReserve Company, beneficiation studies were made on a sample of complex tin-tungsten ore from the Urania mine in Bolivia, South America.The low-grade Urania ore (1.9 percent Sn and 1.55 percent W03) contained a very complex of cassiterite and scheelite with iron sulfidesand quartz. The problem involved in concentrating this ore was the removal of sulfides and silica by stage flotation and gravity concentration for the production of a marketable tin-tungsten concentrate. The sulfides and primary quartzite were readily rejected, but the secondary quartz was intimately associated with cassiterite, and ultimate recovery depended on treatment of minus 560-mesh (theoretical) sizes.The ore was amenable to concentration by ore dressing. Seventy percent of the tin and 83 percent of the tungsten were recovered in a product that assayed approximately 20 percent Sn and 20 percent W03 and that met grade ""F"" specifications of the Metals Reserve Company for mixed tin-tungston concentrates."

Feb 1, 1948

By A. F. Ogg

The installed world steel capacity remains 20% above the present world steel demand. Energy costs have risen enormously in recent years, as illustrated in Figures 1 and 2. The role of the sinter plant is becoming more exacting as it becomes vital to minimize energy consumption. Continuous grate sintering, although pioneered in the United States, has always been the second grade burden preparation route, due to the predominance of easily up- graded ores which were more readily agglomerated by pelletizing. To achieve blast furnace performance up to best world standards, sinter of consistent high quality must be produced with virtually no atmospheric pollution. The plants must be capable of achieving this demanding level of quality whilst utilizing high proportions of revert materials, iron ore concentrates and fluxes . However, with the present difficult economic climate in the iron and steel industry, the economic production of sinter and ultimately steel is becoming increasingly important. The iron and steel industry is looking closely at costs and is identifying the need for sinter plants that will cope with a wide range of sintering materials to give the cheapest blend at varying output levels dependent upon demand. In order to meet these requirements, sinter plant builders are designing plants with particular attention on flexibility.

Jan 1, 1980

By Gary P. Thomason

We have all heard a great deal about how various projects were financed or certain companies were successful in obtaining a bank loan. There are many more projects and companies who fail to get the money they need. At least a portion of these failures, and a large percentage of the frustrations connected with even the successful financings, are a result of not understanding the process of obtaining money. Recent years have seen a proliferation of sources available to finance minerals operations, but let me assure you that these represent only a minor portion of the minerals financing market. The fundamental source of borrowed money to almost all minerals related companies remains the banks. Therefore, understanding the "Loan Approval Process" can easily mean the difference between getting the money or not. In the following pages I hope to provide some insight into what I define as the loan approval process. Having pre-offered my definition, I intend to delineate the various stages of the process and the planning and information I believe should be contained in each. My ultimate goal is to help you think like a banker and, in so doing, stay on top of the process so that you can successfully obtain the funding necessary for your projects.

Jan 1, 1983

By P. A. Lilly, W. Sarunic

In most cases, slope movement monitoring data are collected on a temporal basis and displacement or velocity is plotted against time in order to assist the engineer to make judgements about slope behaviour. Once an unusual behaviour pattern has been established, the data are then analysed to estimate when the key inflection points occur in the data, when the slope movements start to accelerate and, ultimately, when the slope is expected to collapse. The identification of these inflection points is sometimes difficult to achieve with the naked eye. This paper presents the application of a trend analysis technique, known as cusums, to assist in this process. The authors have presented a range of data from various real life examples which highlight the effectiveness of the cusums technique. A key aspect of the cusums technique is the use of a constant (K) against which data trends are assessed. This constant is best derived from slope performance data at each site, as each rock mass will behave in its own unique way. The authors have experienced slopes that have had threshold values ranging from 0.1mm/day through to 10mm/day, and therefore a conservative approach should be adopted when assessing the performance of slopes.

Jan 1, 2006

By D. Harrington

Approximately 6,000 coal mines are operated in the United States. All of them have in some degree the elements that are likely to contribute to an explosion, hence it is surprising that explosion disasters are not more frequent and that many mines have been operated for years and finally worked out and abandoned without experiencing an explosion. The absence of coal-mine explosions does not always indicate that effective efforts have been made to prevent them but rather that the nine has been fortunate in that the combination of circumstances necessary to cause an explosion has not existed. In view of present knowledge of the methods of preventing explosions, disasters are inexcusable and discredit the mining industry. The methods of preventing mine explosions are known to experienced, well-informed persons engaged in coal mining, yet despite this knowledge far to many coal-mine operators continue to use practices and methods that they should know have resulted in numerous explosions. Moreover, many mine workers persist in following past procedure irrespective of consequences and in breaking safety rules or indulging in practices almost certain eventually to result in disaster. Continued failure to apply known common-sense methods of accident and explosion prevention unquestionably will cell for ultimate enforcement of law.

Jan 1, 1940

By James G. Mock

The choice of equipment to be applied to a given installation by the Application Engineer begins with the data as presented to him by the user. This point in the relationship establishes a communication link, which will decide whether or not the correct piece of Overhead Equipment is applied at the most economic advantage to the user. The role played by the user cannot be minimized. No one knows better than he, just what work he expects to accomplish with this piece of machinery. However, all too often, he oversimplifies the requirements, and along with minimal crane and building parameters, merely refers to one of the following crane classifications as defined by The Crane Manufacturing Association of America, as shown in Figures 1, 2, 3, 4, 5, 6 and 7. This approach places the ultimate user in an unfair position, since he has then assumed the status of the machinery designer and must, therefore, assume the responsibility of the success or failure of the operation of that piece of machinery. If the user selects a Class "C" crane for his job requirement, when actually a Class "B" crane can adequately handle the work load, he is not offering the most economic solution to his company and added little to the cranes service capabilities.

Jan 1, 1973

By Wallace Macgregor

The direct investment role of Middle Eastern oil producing countries in future world-wide mineral development probably will be a limited one for the next five years. Their needs and their longer range economic objectives substantially preclude any such risk taking ventures. There is, of course, the possibility of political in- vestment. One hears many rumors and doomsday calculations of what the Arabs might do with the rising accumulation of surplus funds. Up to now, this kind of investment has been more in rhetoric than in money. For the most part, oil producing countries of the Middle East have been, and will be, investing surplus funds with strong emphasis on the preservation of capital. They will seek security first and yield second just like any other prudent investor. In several respects, this is regrettable. A direct infusion of risk capital into mineral development, especially in the Third World countries, is a constructive way of enhancing their earning power which many desperately need just to stave off starvation. It would also be a good way of eliminating material shortages in the industrialized world. Most important of all, it would help to ultimately reduce inflation without imposing the hardship of recession. So why isn't it done?

Jan 1, 1975

By M. K. Mishra, U. M. R. Karanam

Relative to slender pillars, larger size pillars exhibit improved strata control. Fly ash, though traditionally treated as a waste product, is emerging as an alternate engineering material. This paper deals with the development of a strong fly ash composite material with additives. The geotechnical properties of this fly ash composite were determined and used to trap model core pillars, which resemble squat pillars. The trapped samples were tested under uni-axial loading in the laboratory and the results showed higher load-bearing capacity of the model core pillars. The reinforced fly ash composites provide lateral confinement and exhibit improved post- failure behaviour of the model cores.

Jan 1, 2008

The wealth of a nation can be measured many ways, but one of the most important measures is its natural resources, particularly minerals. Minerals provide the foundation upon which economic prosperity and defense preparedness rest. Assessing our energy and mineral resources and assuring their development is in the best interests of all our people continues to be an important national goal. Since its founding in 1910, the U.S. Bureau of Mines has established itself as the world's premier minerals information and research agency. Its authoritative, comprehensive data and pioneering research have contributed significantly to a strong U.S. mineral position in the world.

Jan 1, 1990

By Mark S. Sanders

There is a growing awareness among mining professionals that the human factor plays a significant role in safety and productivity. Since the 1960's, the science of human factors, or ergonomics, has been making inroads into the mining industry, and a considerable amount of research has documented human-factor-related mining problems and solutions. This Bureau of Mines report is directed toward summarizing the application of human factors to improving safety, productivity, and the general physical and psychological working conditions of miners. The aim of this report is to familiarize the readers with the role of human factors in the mining industry and the benefits that can accrue by systematically applying available human factors principles and data. The text contains 10 chapters dealing with human, equipment, and environmental factors. Each chapter builds on the previous chapter; therefore, it is recommended that the chapters be read sequentially However, if the report is used as a supplemental text, say in a mining safety course, chapters can be assigned in any order to supplement other readings.

Jan 1, 1988

By Paul M. Hall

In the last several years, the coal mining industry has made significant changes in the design of longwall mining systems to make them more productive. Some changes, such as increasing the length of the coal faces and increasing the capacity of the face conveyors, have resulted in problems with achieving sufficient motor torque to start and operate the longwall face conveyors. Other changes, such as increasing the size and/or decreasing the percent impedance of longwall power center transformers, have resulted in problems with the short-circuit currents on the transformer secondaries exceeding the interrupting ratings of the molded case circuit breakers used to protect the secondary circuits. A survey of 24 longwall mining systems in northern West Virginia was conducted to investigate both problems. The results of the survey are presented and analyzed. Several recommended solutions to the problems are presented to enable the coal mining industry to design safe and productive longwall mining systems.

Jan 1, 1982

By P Vasconcelos, X D. Deng

Numerous supergene manganese oxide deposits are developed inSouth China as a result of weathering of a thick sequence of Paleozoic marine Mn-bearing sedimentary rocks, consisting mainly of limestones, cherts and black shales that were intensely folded and faulted due to multiple episodes of tectonism since the late Triassic. The ore minerals are dominantly pyrolusite, cryptomelane, nsutite, lithiophorite and braunite. The supergene manganese ores contain Mn ranging from 20 to 44 wt per cent; manganese oxide deposits derived from cherts and black shales also contain recoverable levels of Co, Ni, Cu, Pb and Zn. 40Ar/39Ar dating of potassium-bearing manganese oxides reveals that extensive supergene manganese ore formation started at least in the earliest Miocene and persisted to the Present. Ages of the deposits show a close correlation to tectonic stability, with the oldest in tectonically quiescent areas and the youngest in active areas that have subjected to continuous uplift and thus significant denudation. The prolonged wet and hot climate since Oligocene and the balance between weathering and erosion, which is parameter to the tectonic stability, are the ultimate controls on the formation and distribution of South China supergene manganese oxide deposits. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By J. K. Lemley

The human element in large measure dictates success in contracting relationships. Because of our professional backgrounds, we view contracts primarily as either engineers, contractors or owners. A beneficial contractual environment--one in which decisions, risks and benefits are shared--demands equal consideration of all three points of view. Most of the older cities in the United States, for example, suffer from bad contracts--generalized, patched-together documents that represent an accumulation of modifications originally written to compensate for specific situations that have occurred over the years. Because such documents lack coherence, they often present conflicting instructions which lead to defensive, ultimately destructive attitudes among the parties involved in the day-to-day administration of the project. Good contract development begins with a strong central philosophy to which the details of the contract can be related. First, the owner should establish a comprehensive philosophy in which risks between the parties are identified. Following this, a specific contract document can be written to satisfy this established philosophy. The contrast between two opposed contractual situations, NYC Water Tunnel Number Three and the Seabrook Nuclear Power Plant Cooling Water Tunnels, illustrates how comprehensive, well-written contracts--contracts which share both risks and benefits--provide the basis for achieving quality construction that will reward engineer, contractor and owner.

Jan 1, 1983

By Warren E. Morrison

This study was prepared in response to the need for a series of data that reflect the basic flow pattern of energy resources in the United States. To effectively measure and analyze energy,2 it is necessary to prepare balances that reflect both production and consumption, and the various forms energy resources take at different stages of utilization. Before energy can be measured it must also be put into a common unit. In this study the common unit us d is the British Thermal Unit (Btu). The ideal point to survey energy is at the stage of final ultimate use, representing the useful work derived from the interaction of energy inputs and the prime mover. Unfortunately this concept of efficient or useful work from energy output cannot readily be measured in the aggregate. With the present available official data, energy measurement can be carried to the point of calculation of net inputs of energy3 into the economy at various stages of utilization. However, preparation of energy balances, on a net basis is hampered by the fact that this can only be done for years when the censuses of Mineral Industries and Manufactures are taken, usually at 5-year intervals.

Jan 1, 1964

By J. Fellowes, V. Landais, J. Robson, J. Carr

"Aerospace Al-Zn-Mg-Cu (7xxx) alloys are known to be susceptible to environmentally assisted cracking (EAC). This phenomenon has been studied intensively for many decades, leading to empirically adopted methods to mitigate this problem through overaging and composition design. In parallel, many theories have been developed to explain EAC in 7xxx, but none is yet universally accepted. Today, a number of emerging techniques offer potential to shed new light on EAC in 7xxx. The purpose of the present paper is to demonstrate how X-ray tomography (XCT) combined with electron microscopy can be used to identify the true crack path in 3-dimensions, and hence identify material for site specific electron microscopy analysis. Composition mapping over large areas to high accuracy has been performed using a modern electron microprobe analysis system. This has been combined with transmission electron microscopy to investigate local composition in matrix and precipitates at high resolution. This combination of techniques across length scales offers the potential to provide new insights into the links between local composition, microstructure, and EAC resistance.INTRODUCTION Environmentally-assisted cracking (EAC) is a phenomenon which dramatically decreases the performance of metals and can cause premature failure of large structures. Observed in situations where components were not subjected to critical loads and no widespread corrosion was involved, this type of brittle failure is extremely difficult to predict. The EAC designation covers a number of phenomena, e.g. stress corrosion cracking (SCC), hydrogen embrittlement (HE), corrosion fatigue (CF), etc. Initially identified in steels, EAC can also affect other metals such as high-performance aerospace aluminium alloys, and this phenomenon has been a concern for industries for decades. Extensive research has been conducted on the effects of various environments (moist air, saline water, dry hydrogen gas, etc.) on microstructures and crack propagation, however no consensus has been reached and the exact nature of the mechanisms that control EAC is still being debated (Birnbaum & Sofronis, 1994; Gangloff, 2007; Holroyd & Scamans, 2013; Lynch, 2012; Oriani, 1972; Scamans, Alani & Swann, 1976, Young & Scully, 2002)."

Jan 1, 2018

By P. Scinto, P. Hudson

"Modern day ore bodies are becoming increasingly harder, more abrasive and lower grade. The Mako deposit is located in Senegal and consists predominantly of primary mafic and felsic lithology that are both very competent and very abrasive ores (Axb < 30, BWi >20 and Ai >1.0). The deposit was initially discovery in 2010 and the Toro Gold management team fast tracked the Mako Project through development and into production to achieve its first gold pour in January 2018. The comminution circuit comprises primary crushing single stage SAG milling with recycle crusher (1oCR SS-SAC). The mill reached design throughput and grind size seven weeks after first ore. The Mako project marks another successful international application of single stage milling, which represents a simple and easy to operate comminution circuit for small-to-mid size projects with a low capital cost. This paper describes the ore interpretation, comminution modelling, grinding circuit selection and design, as well as an overview of the commissioning and ramp-up of the mill.INTRODUCTION The Mako Gold Project is operated by Toro Gold Ltd., which holds a 90% interest in the project. The project is located in south-eastern Senegal in the Kedougou region, close to the Gambia river and township of Mako. The Mako deposit lies in the “Kenieba Window” of eastern Senegal and western Mali, which hosts a number of gold mining operations and development projects. The Mako Gold Project has an estimated life of 8 years with overall recoverable gold estimated at 924 koz. The process plant is designed to treat 1.8Mt/a of ore and produce 128 – 143 koz of gold per annum. Lycopodium Minerals Pty Ltd (Lycopodium) was appointed to provide feasibility studies and EPCM services for the greenfield project. Forming part of consultancy services provided by Lycopodium, Orway Mineral Consultants (OMC), a subsidiary of Lycopodium, was involved in the design, commissioning, ramp up and ongoing post commissioning support of the comminution circuit."

Jan 1, 2019