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By W. Marnette

The copper demand is booming. New epicentres with strong dynamic economic growth have arisen in China and other emerging markets. Furthermore, Europe contributes to higher copper demand due to positive economic growth. China and India are therefore expanding their smelter industries, with the backing of a coordinated policy of global raw material sourcing, which includes investments in raw material deposits and state-run measures to support their international trade and competition. Likewise, Europe faces scarcity of copper raw materials. The copper industry in Europe is historically grown and shows excellence in environmental protection and technical leadership. Recycling has always been an important sector. This reiterates the recycling-know-how which exists in the European sector. However, Europe still relies on importing a considerable amount of raw materials from foreign countries. As a result, the global competition for copper and copper raw materials has increased. Tough competition as regards industrial location and costs, the emergence of corporate concentrations and the use of protectionist trading practices by countries like China and India, which distort the markets, now determine the picture. Hence, a copper smelter in Europe is forced to develop tailor-made concepts to safeguard and improve its international competitive position. It is imperative that this is also flanked by improved conditions on the local level and a European raw material policy which takes account of the changed situation on the world market.

Jan 1, 2007

By R. L. Grayson, Y. J. Wang

An integrated approach to the management of underground coal mine production and cost is presented. A conceptual model for objectively analyzing an underground mine to obtain lower cost and higher productivity from operations is outlined. The model is designed to provide mine managers with a quantitative, decision-assisting methodology that can be used in formulating timely responses to fluctuations in operations. It consists of a productivity fore- cast component, routine use of current resource consumption factors, a linear programming scheduling component, a manpower loading analysis, and an inventory control component. The model is applied to an underground coal mine.

Jan 1, 1990

By J. R. Thoenek S. L. Windes

The amplitudes and frequencies of vibratiolls of a four-story stucco building were measured by specially developed electrocapacitive seismometers. Records were made on three floor levels with as many as 10 seismometers recording simultancously. Sources of vibration were: (1) an electric motor with unbalanced pulley, maximum speed 1800 r.p.m., maximum centrifugal force 90 lb., (2) truck traffic (both solid and pneumatic tires) moving over inequalities in the street in front of the house, (3) falling weights dropped on the street pavement from different heights, (4) miscellaneous sources, including a man jumping on the floor of the house and slamming doors. Tests were made to determine the natural frequencies of floor and wall panels by varying the speed of the unbalanced motor and by exciting the panels with a single impulse. The vibrations recorded were compared to records of vibrations from quarry blasts and it was observed that the vibrations from truck traffic were comparable to those recorded from quarry blasts and in no instance was there any damage to the building. As the tests were all of a negative character as far as damage was concerned, no index of destruction is formulated. Instead, the records are presented simply as vibration measurements obtained in an ordinary house under typical conditions.

Jan 1, 1940

By Dixon CA

In the early 1970s, Jim Walter Resources, Inc. (JWR) embarked on a coal mine expansion program that was unparalleled in the history of the United States. With a small nucleus of people then operating two rapidly depleting captive mines, action was initiated to develop four of the deepest mines in the United States. Because of the depth of these mines, operational and technical problems were anticipated. However, because of the high quality of the coal (Blue Creek Seam), the financial risks involved were acceptable. The total investment to get the expansion program completed (to get the new mines to full capacity) would represent an investment of over US$ 500 million.By the end of the decade of the 1970s, the Company had grown to 2100 employees who were producing 1640,000 tonne of saleable coal per year, a productivity rate of 3.9 tonne per man-shift. This productivity rate was not sufficient to maintain a profitable, viable organisation. Therefore, if the operations were going to survive, it would be necessary to improve productivity tremendously, a task which would tax the resources and imagination of all employees.

Jan 1, 1991

By Andrzej Wala, Waclaw Dziurzynski, Janusz Tracz

Recent advancements in computer hardware have led to the development of new ventilation planning software for PC's. These programs now can be run more quickly and can display their outputs with graphical techniques. Only a few of the existing programs have the capability to display the output data graphically on plotters. Graphical presentation of ventilation simulation data is essential for quick and sure comparisons of alternative analyses. Recently a noticeable growth has occurred in the application of graphics for display and interpretation of the data that have been developed by simulation procedures. The process of mine ventilation network analyses used for planning and design can benefit from this development. The authors describe and present graphics-assisted software that has been developed to work with a mine ventilation simulation program. This software has some of the following features: - graphic editor on screen, - graphical display of output data on screen (EGA, VGA), - graphical display on plotter or printer, - scaling capability (desired part of the entire schematic can be displayed), and - such values as flow, pressure loss, gas concentration for branches, and pressure and elevation at junctions can be presented as labels.

Jan 1, 1991

The process of establishing the design criteria is the key step in commencing a new project.. The method for establishing design criteria and translating them to a workable plant design is described. INTRODUCTION The use of activated charcoal to recover gold from alkaline cyanide leach liquors is the most rapidly expanding technology in hydrometallurgy today. The process, known as carbon-in-pulp (CIP), has replaced countercurrent decantation as the method for recovering gold by cyanidation. Carbon-in-pulp entails mixing activated charcoal with a ground ore-water slurry containing gold cyanide, allowing the charcoal to adsorb the gold, and then mechanically removing the gold loaded charcoal from the pulp. The pulp is sent to tailing disposal and the loaded charcoal is sent for gold bullion production. Activated charcoal's affinity for gold has been docu- mented for over one hundred years. In the first cyanide plants, one of the preferred methods of stealing gold was to place a piece

Jan 1, 1982

By A. D. Cameron

La voladura es una de las primeras operaciones del ciclo de minado y su impacto es fundamental en la productividad y economía de la mina. Por ello, su diseño y su evaluación de resultados debe realizarse considerando el contexto de la operación minera en su totalidad como en términos de productividad y costo. En este sentido, el presente texto señala algunas de las técnicas empleadas para mejorar la optimización del trabajo de voladura, considerando las herramientas de software utilizadas por el ingeniero de voladura como el análisis del diseño, la predicción y medición de los resultados del disparo. La dificultad estriba en poder relacionar los resultados de la voladura, como la fragmentación, dilución y daños, a los parámetros de productividad tales como: el ciclo de minado, el tiempo de limpieza y la producción de la chancadora, etc.. La poca disposición a utilizar las herramientas de diseño y monitoreo disponibles se relaciona a la dificultad de poder cuantificar el impacto de los malos disparos en la marcha económica de las minas.

May 25, 1998

INCREASE OF THE OIL CONSUMPTIONIt is of the greatest interest to study the prospects open today for the petroleum industry by looking back to the past years.The' results for the past 15,years can be said. to be- satisfying; - the develop-ment of the petroleum industry has sustained a very fast tempo and the world consumption of energy has around the years 1960-1961 - reached aòpeak figure.Undoubtedly, the petroleum industry is the principal beneficiary of the growth of world, energy demand. For the caning years a slackening of the rate of expansion is'. likely to be expected; but will. not alter the general trend. This ' slackening of expansion may be explained, partly by a better use of the energy consumed and by the increased use of new types of energy, mainly natural gas.Although.the development of world energy demands follow structural and tech-nical modifications".,-At. can be foreseen, without any doubt, that the petroleum products. consumption. vri 11 be less affected than any other type of energy by this limited reduction in the rate of increase.

Jan 1, 1962

By Bernard H. Hertlein

The introduction of LRFD methods for structural design has been a gradual process by AASHTO, ACI, AISC, ASCE, and the FHWA, which has largely been ignored by the deep foundations industry. In 2007, however, the industry has been obliged to embrace LRFD for any deep foundations on projects involving federal funds. The authors are concerned that the risks caused by the need for, and the difficulty of providing, reliable quality assurance, will result in unnecessarily high safety factors that will defeat part of the purpose of LRFD. A primary attraction of LRFD for owners and engineers alike is that it promises more efficient design, and therefore cost reductions. Unfortunately, a key element of LRFD philosophy is often overlooked - that the applied safety factors can be rationally reduced, often allowing less material to be used, thus saving costs, but only if all the risk factors involved are identified and closely controlled. This means that both the quality of the materials and the quality of the construction work must be adequately monitored, and held to an acceptable standard. In the case of deep foundations, the soil in which the foundation is constructed is also a critical component that must be taken into account in the assessment of risk factors.

Jan 1, 2007

By S. S. Deshmukh

An important element of evaluating a materials- handling system by simulation lies in being able to examine the details of the proposed operation in a fashion which closely approximates real behavior. The added factor of flexibility permits including or deleting those parts of the problem which can be shown to be important or trivial. Used carefully, simulation can match manpower and equipment far more efficiently than conventional calculations. The same is true of interacting equipment systems. This efficiency results from being able to simulate the real fluctuations in a system by using empirical probability distributions compiled from existing operations. Simulation eliminates guessing as to efficiency, absenteeism, bunching, and the broad host of delays that influence productivity and substitutes operating data in place of the usual factors. In this respect, simulation improves detail and confidence in the reliability of engineering estimates.

Jan 1, 1970

At the Kidd Creek mine operated by Ecstall Mining, Ltd. near Timmins, Ontario, Honeywell has installed a sophisticated new quick- thinking computer system that keeps tabs on conditions along three separate processing streams at once and relays continuous 60-second data to the mill operator. Believed to be the first of its kind, the system picks up data from two independent x-ray spectrometers simultaneously. A digital computer from Honeywell's Computer Control Division receives and interprets real-time information gathered by online x-ray analyzers, and the system then advises control room operators of the relative amount of each of five elements at five points in each of the three process streams. The system is reported to provide a quantitative analysis of the five elements at a given point in the process within one minute-which is about 120 times as fast as a chemical laboratory assay could be performed. With this instant data at his command, the mill operator can make timely process adjustments to correct any deviation from optimum flotation results, thus salvaging valuable minerals that would inevitably be lost with slower detection methods. The minerals recovered at Kidd creek are copper, lead, iron, silver and zinc.

Jan 8, 1968

By J. A. Eisele, D. J. Bauer, L. E. Schultze

Approximately 100 million mt of magnetic reject tailings, which contain apatite and about 1% yttrium and rare-earth elements, exist in the eastern U.S. as a result of iron ore mining operations. At the present time, no economic process is available for recovering yttrium from this material. The U.S. Bureau of Mines (USBM) studied the problem to determine if an effective low-cost method could be found, thereby increasing our domestic yttrium reserves. [Fig. 1] is a line drawing of a photograph taken during microprobe analysis of a sample of the tailings, and shows the distribution of yttrium. Typical analysis of this material is 0.14% yttrium and 1.1% rare-earth elements (mainly lanthanum through neodymium). Over half of the yttrium is present as a hydrated Ca-Y silicate deposited along interfaces in the grain structure; whereas, the remainder of the rare-earth elements occur as Ca-Fe-RE silicates. The remaining yttrium and rare-earth elements are in solid solution with the

Jan 1, 1977

By Jerry L. Taylor

Utah Power & Light Company is an electric utility serving approximately 1.8 million people in Utah, Idaho, and waning. In order to supply coal to fuel power plants, Utah Power & Light awns three mines in central Utah. Planning for these mines is aided by a computer program developed by the staff mining engineers. This program, when supplied with the pertinent seam and mining configuration data, calculates the time to mine each section. This allows the planning engineer to estimate accurately the time required to extract pillar sections or develop longwall panels. The program's greatest benefit, however, is its ability to allow the engineer to examine quickly, different combinations of possible mine layouts to determine the most efficient plan. Computer aided mine planning has been used at Utah Power & Light Company since 1979, and has significantly improved the accuracy and quality of mine planning.

Jan 1, 1983

THERE are two general classes of problems in connection with electric furnaces. First, those relating to the best utilization of the electrical power inside the furnace; second, those connected with the bringing of the electrical power to the point where it is to be utilized. Referring particularly to the latter class of problems, many calculations have been made, covering a wide variety of furnaces, to check the electrical capacity and power factor found from test. The following analysis, made for the purpose of determining the maximum capacity and approximate performance of a new furnace, to operate at 160 volts on a 60-cycle circuit, may be of interest. The first characteristic necessary to determine is the inductance, since this is the factor that limits the amount of power which can be put into the furnace. Inductance is calculated from the dimensions of the furnace, according to formulas of the U. S. Bureau of Standards,1 as

Jan 10, 1918

By F. H. McDowell

About a year ago Dr. Raymond, as engineer of Messrs. Cooper, Hewitt & Co., together with Mr. Rothwell, was considering the removal of the ore-floors and pillars from the Peters Mine at Ringwood, N. J., where the limit of profitable working by the old method of mining had been very nearly reached. Mr. Ferdinand Ruttmann was engaged to make the survey which forms the basis of the accompanying diagrams. At first it was thought that some method of mining and filling might be introduced with advantage; but after a careful study of the operations at the Tilly Foster it was decided to adopt the system of stripping.

Jan 1, 1890

Major changes occurred in the management of loss prevention and risk management at operations in North and South America due to increased insurance premiums following the Olympic Dam fire in Australia in 2001. There are many different scenarios on how fires can develop and the estimated maximum losses (EML) those fires can incur. The EML is utilised by insurance companies to determine the cost of insurance premiums. The cost of insurance can be controlled at existing and newly designed solvent extraction (SX) plants by using risk reduction methods and design criteria to limit the fire exposure. A review of data collected during several loss prevention risk assessments can show how a budget can be protected from dramatically increased premiums and see which design of SX plant and fire protection standards best apply to your operations. The paper will investigate the pitfalls of existing materials of construction, capacity, geography, management practices, fire risk minimisation, and fire suppression systems. Intelligent engineering and managerial improvements implemented by the operations in the Americas in the past two years have further minimised the fire potential and benefited companies in insurance renewal negotiations.

Jan 1, 2003

The Tuesday morning session opened at 9:00 a.m. and was presided over by Mr. Homer Hyatt, Safety Director, North American Coal Corporation, Western Division, Castle Gate, Utah. Mr. Hyatt introduced Mr. Richard F. Walker, Vice President, Engineer & Planning, Electric Department, Public Service Company of Colorado, Denver, Colorado. Mr. Walker is a native of the State of Nebraska, a graduate of the University of Colorado with a BSEE degree in 1949. He has been associated with the Public Service Company of Colorado for almost twenty years and in the above capacity for the last one and one-half years. Mr. Walker?s subject was "Our New Plants and Coal. (See index for printed text of Mr. Walker's paper.) Mr. John F. O'Leary, Director, U.S. Bureau of Mines, Washington, D. C. spoke on the ?High Cost of Economy.? Mr. O'Leary graduated from George Washington University in 1950 with a degree in Economics. In 1950, he joined the Bureau of Mines. In 1963 he was appointed Deputy Assistant Secretary, Mineral Resources, U.S. Department of the Interior. In 1967, he was appointed Chief, Bureau of Natural Gas, Federal Power Commission. In 1968, appointed Director, U.S. Bureau of Mines, Washington, D.C.

Jan 1, 1969

By Timothy Stark

At present blasters are strictly liable under tort law for personal injury and property damage caused by ground vibrations and/or air overpressures. The application of strict tort liability to vibration and air overpressure damage has resulted in litigation that has hampered and probably will continue to hamper the blasting industry. There are many case histories in which blasters have been sued for the appearance of cosmetic cracking, some of which have involved frivolous claims and marginal expert testimony (Oriard 1999). This litigation has resulted in additional costs to the blasting and construction industries and the American public because there are usually many plaintiffs involved and each case is usually adjudicated separately instead of under a class-action format. It is proposed herein that blasters not be held liable for vibration or air overpressure damages unless their conduct is proven to be negligent. A number of reasons are presented for raising the legal standard from strict liability to negligence including: (1) improvements in blasting technology that allow blasting to be conducted without substantial risk of damage and if damage does occur it is likely to be cosmetic, (2) establishment of conservative ground vibration and air overpressure damage limits for typical structures, and (3) established industry standards for construction blasting.

Jan 1, 2002

By Admire Chaendera

A gas jet was blown through submerged nozzles to stir the bath in the presence and absence of slag. Mixing and mass transfer rates were then studied. Water and kerosene (10% by volume) were used to simulate the metal and slag phases respectively in the cold model. The mixing time (Tmix), defined at 99.66% bath homogeneity level, increased with bath height and decreased with an increase in the gas injection rate. Its value in the model vessel was related to gas flow rate (Q), bath weight (W), and bath height (H) by, Tmix = 4.39Q-0.73W0.24H1.12. Inclusion of the slag phase increased Tmix by about 16% and the mass transfer parameter, [(Reloc,r)0.25(Ret)0.32], values by about 32%. Mass transfer rates were higher near the bath surface and in the gas-liquid plume region. They increased with gas flow rate but decreased with an increase in bath height. The relationship, K Q0.08, showing derived mass transfer coefficient (K) dependence on the gas injection rate (Q) was established. The proportionality constant in the equation varied with gas flow rate and sample location.

Jan 1, 2006

Alliance Gold Mines was established in the early part of 1994 to acquire the assets of Diamin Resources NL at Maldon, Victoria. These comprised Exploration Licence 3422, some 20 sq km in area and enclosing the main part of the Goldfield, and a CIP plant - with a nominal capacity of 250 000 tpa - which was commissioned in 1988. Between 1988 and 1992 Diamin had mined - by open pit methods - and milled around one million tonnes of low grade gold ore, and recovered 55 000 ounces of gold. By 1992 the known shallow resources had been depleted. Historical gold production from the Maldon field is about 1.75 million ounces, at the surprising average recovered grade of 28 g/t. The last significant mine closed in 1926: since then there has been no comprehensive exploration program, though Lone Star Exploration NL tested part of the field for shallow open-pittable resources in the 1970s and Carpentaria Exploration Company Pty Ltd carried out widely-spaced drilling on the three main reefs from 1979 to 1982. Diamin (1983 - 1994) commenced a careful compilation of old mine records and newspaper clippings, and drilled several cored holes.

Jan 1, 1996