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In the sixteenth century the Spanish Captain da Alvaro Soavedaro, on a search for the explorer Ferdinand Magellan, came across the main island of New Guinea which he named Isla del Oro (Island of Gold). Since that time exploration for, and mining of, gold has been pursued by many, culminating in . the development of major world-class projects in the latter part of the 20th century. Though various prospectors have panned for gold and small gold mining projects were undertaken through the seventeenth and eighteenth centuries, it was not until the 1880's when mining became a more concerted economic venture. Misima and Woodlark Islands in Milne Bay, Gura-Ackera and Yoada in Oro, and Lakekamu in Gulf Province and Keveri in Central Province were all gold producers by late nineteenth century. It was in the 1920's that corporations began mining in PNG and with the commencement of production at Panguna in Bougainville in 1972 a new era of mega-project mining began.' Today there are two large mining projects producing mainly gold and copper. The first, already mentioned, is Panguna on Bougainville Island. This project has provided Government with $US 475 million in taxes. ok Tedi is the second large mine development located in Western Province. It began production in 1984 with the extraction of the deposit's "gold Cap".

Jan 1, 1987

By J. J. Kanter

A. I. Blank.*-—Mr. Kanter has spoken of failures from causes other than creep itself in metals that are subjected to creep stresses. Would it be possible for the author to enlarge on this very important matter of "cataclysmic types of failures? " J. J. Kanter.—Of course, it is always a delicate matter to discuss specific failures. I would prefer to keep the present discussion on fundamentals and principles. H. L. Burghof.*—Mr. Kanter, I should like to ask what you consider the responsibility of the designer in avoiding stress concentrations that would lead to these types of failures? J. J. Kanter.—lt was my feeling in looking over the papers of this symposium that they were significantly lacking in consideration of what happens to the metals when strained under conditions that lead to rupture. Often creep tests are run that produce only a fractional percentage of the deformation, in several thousand hours. That kind of information gives the designer no assurance whatever that cracks will not result in his structure at points where stress concentrations, and therefore deformation concentrations, exist. I think anyone in this day and age who presents a paper on creep should incorporate with those studies a thorough investigation of creep rupture if it is expected to make an impression upon the design engineer.

Jan 1, 1945

By Yutaka Mochida

OUTLINE Beginning in 1946, a careful geological survey was made of the Tsugaru Straits. In 1964, excavation of the exploratory tunnels were started to observe the characteristics of faults and rock formation directly, and to study construction methods of excavation and sealing water inflow. In March 1971, the investigation stages were over, and in April 1971, the construction project was authorized from the government. The geological features in the straits may be divided into three broad classes. One third consists of andesite on Honshu side. The other two thirds consists of tuff. The middle of the straits consists of tuff, so-called Kuromatsunai-layers. On Hokkaido side, it consists of tuff, called as Kunnui-layers. There are nine noteworthy faults on the route. Prior to the excavation of the main tunnel, the horizontal pilot tunnels and service tunnels are made. Exploratory borings are taken to confirm the geological conditions and the presence of gushing water. Groutings for sealing water inflow are carried out when necessary. In geologically bad conditioned sections such as disintegrated or fractured zones, special methods are applied. In geologically good zones, the tunnels are bored through using the same methods as for a mountain tunnel driving. The pilot tunnel being constructed at the sea bottom is under direct control of the Japan Railway Construction Public Corporation. The service tunnel and the main tunnel are being excavated by contractors.

Jan 1, 1981

By A I. M Ritchie, G P. Timms

Monitoring of water infiltration into WhiteÆs waste rock dump at the Rum Jungle mine site in the Northern Territory, Australia, started in 1983, and has since produced a unique and long-running data set. Following closure of the uranium mining operations at the site, a soil cover was constructed on the dump in 1984 primarily to reduce water infiltration into, and the quantity of low quality effluent out of, the waste material. The performance of the cover in reducing water infiltration has been monitored using ten lysimeters installed across the dump prior to construction of the cover. Over the past eight years or so, the average infiltration rate as measured by the ten lysimeters appears to have risen compared to the early years of monitoring. The significance of this apparent increase is discussed given the variability observed in the data from individual lysimeters, and the variability in the rainfall. Estimates of the infiltration rate as measured by each of the lysimeters are examined using statistical tools. It is concluded that the infiltration rate has increased with time and with increasing rainfall. The increase with time is a stronger factor than the increase with rainfall. It is further surmised that the cover system at the locations of the lysimeters is less effective now at reducing infiltration into the dump than it was when newly installed.

Jan 1, 2003

By M. R. Meyer, W. T. Walter

A great deal is known, in a qualitative sense, about the performance of CMI EB-36 centrifuges. The manufacturer can give reliable guidance for the proper operation of its centrifuges and can give general estimates of expected product moisture and recovery. Quantitative estimates of the effects of changes in the various operating parameters are more difficult to find. The engineer faced with designing a preparation plant may be without the specific data needed to make decisions. For example, to obtain optimum product moisture when drying 9.5 mm X 595 µm (0.4 in. x 28 mesh) coal the centrifuge manufacturer recommends having no more than 5% -595 µm (-28 mesh) material in the centrifuge feed. They know that more -595 µm (-28 mesh)material in the feed will cause higher product moistures, but they usually cannot quantify the increased moisture or describe the shape of the product moisture versus -595 µm (-28 mesh) in the feed curve. This study was conceived to provide quantitative information on the EB-36 centrifuges, focusing on product moisture, recovery, and size degradation. All of the centrifuges tested were Model EB-36 dryers from Centrifugal and Mechanical Industries Inc. (CMI), with feeds in the nominal 9.5 mm x 595 pm (0.4 in. x 28 mesh) range. These are typical centrifugal dryers in this application, and many were available for testing.

Jan 1, 1984

The Institute conducts jointly with the American Society of Civil Engineers, American Society of Mechanical Engineers and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them of certain properties. United Engineering Trustees, Inc. When Mr. Carnegie made his gift which made possible a home for the engineering societies, a separate corporation was organized to act as a holding company and to manage the common property. This was long known as the United Engineering Society, but the name has now been changed. to one which more nearly reflects the real function of the corporation. It holds title to the Engineering Societies Building and to various funds placed in its charge and is managed by a Board of Trustees, of which three are chosen by each of the four societies, American Institute of Mining and Metallurgical Engineers, American Society of Mechanical Engineers, American Institute of Electrical Engineers and American Society of Civil Engineers, which have equal and undivided interests in the property. The land and building cost two million dollars. During the gear 1934, the constitution and By-laws of The United Engineering Trustees, Inc., were thoroughly revised and a better organization of its functions was affected: The Engineering Foundation and the Engineering Societies Library were made "departments? of the United

Jan 1, 1936

By Jerome F. Thomas

The primary purpose of this paper is to review the fire and explosion hazards associated with hydrocarbons heavier than methane. Methane is the classical hydrocarbon encountered in mines whose presence is generally due to bacterial decomposition of organic debris. The higher hydrocarbons are more likely to be found during tunneling when petroleum products either natural or man made are encountered. Fires may be defined as rapid gas phase oxidations accompanied by the rapid evolution of light and heat. Explosions may be defined as uncontrolled fires. The rapidly expanding gases resulting from combustion exceed the speed of sound and generate percussive forces. The essential elements for a fire or explosion are shown on Figure 12: (1) a gas phase explosive mixture and (2) an ignition source. The paper will attempt to review various aspects relative to the explosive mixture; The concentration and composition; Techniques for detection; Techniques for ventilation to reduce concentration below explosive limits. The ignition sources are also listed on Figure 12. An arc originates from an electrical source such as electrical switches, relays and motor brushes. Static electricity can also be an arc source and may be generated by air flowing through rubber bases or a rapidly moving endless belt. A spark is generally associated with abrasion of iron metal. A flame source may be a match, candle. cutting or welding torch, or engine exhaust. If

Jan 1, 1974

By William C. Aitkenhead, John A. Jaekel

Uranium deposits in the Spokane Indian Reservation, as well as those around Mt. Spokane, are essentially low grade, much of the ore containing less than 0.2 pct U808. The Mining Experiment Station of the Division of Industrial Research, State College of Washington, has been engaged in intensive research on the amenability of these low grade ores to froth flotation. The results: successful flotation of autinite, chief mineral constituent. At the outset of this work the goal was a concentrate of 1 pct U308 with a 90 pct recovery from ores containing less than 0.2 pct U3O8. Most of the work has been done on argillite ore from the Midnight mine on the Spokane Indian Reservation. The goal has not been attained using this ore, but samples of the granite ore from Mt. Spokane yielded successful results. For example, a concentrate containing 11.2 pct U308 was produced from a Mt. Spokane high grade ore containing 1.27 pct U3O8 with a recovery of 97.8 pct. Another Mt. Spokane ore yielded a concentrate of 5.0 pct U3O8 from an ore containing 0.13 pct U3O8, with a recovery of 85 pct. This same ore gave a recovery of 93.5 pct when the grade of concentrate was reduced to 2.0 pct.

Jan 1, 1959

By Boyce WH

Earthquakes are the most frightening and devastating natural phenomena known to mankind. They strike without warning and their consequences can be disastrous in terms of the toll of human life, financial crises related to the damage or destruction of man-made structures and the social and economic effects on a wide spectrum of the affected communities in the aftermath of the event. Such situations can be widely attested to by most areas around the Pacific Rim. Indeed, the threat of earthquakes is always imminent because of the geological-tectonic nature of the region as manifested by past experiences. It is patently obvious that earthquake occurrences are not only a geological hazard but also pose a serious social danger. When one considers the 19 September 1985 Mexico (Michoacan) earthquake (Mitchell at al., 1986), the necessity of continuing research is of paramount importance. An estimation . of earthquake risk encompasses both qualitative and quantitative aspects and demands a multidisciplinary research effort integrating seismology, tectonics, geology, enginering, sociology, economics, insurance and governmental policies (Bolt, 1978; Booth, 1984). These roles in mitigating such a hazard have been aptly discussed by Press (1985). A series of discussion papers based on an intergovernmental conference covering the whole scenario were published by UNESCO (1978). A comprehensive case history was provided through a workshop on the 1886

Jan 1, 1987

By Gerrit V. R. Goodman, Edward F. Divers, Charles D. Taylor

Future mining systems will possess the ability to cut from crosscut to crosscut where advances could exceed 30.5 m (100ft). However, limitations arise when ventilating such mining systems. In deep advance mining, there will be no workers at the face to manually advance ventilation tubing or curtain. Additionally, traditional methods provide no means for maintaining face ventilation after the miner backs out. Problems such as these have suggested the need for innovative ventilation methods compatible with deep advance mining systems. The Bureau of Mines is currently considering a number of innovative ventilation schemes. One such method is the use of a jet fan to ventilate a deep cut. A jet fan is simply a freestanding fan using little or no ducting to direct the ventilation flow. Previous testing in large metal-nonmetal mine entries showed that jet fans provided adequate face ventilation for deep advances in large headings. Current testing will determine the application of jet fans in ventilating smaller coal mine entries. Another approach considered compatible with deep advance mining will use either exhausting or blowing tubing that can be remotely extended from crosscut to crosscut. During the mining cycle, such a device would extend automatically as the miner sumps into the face. The Bureau of Mines is considering several different operating designs using this tubing.

Jan 1, 1991

The Institute conducts jointly with the American Society of Civil Engineers, American Society of Mechanical Engineers and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them of certain properties situated at 29 West 39th Street in New York City United Engineering Trustees, Inc. When Mr Carnegie made his gift, "for the erection of a suitable union home" for the engineering societies, United Engineering Trustees, Inc (then United Engineering Society) was chartered un¬der Chapter 703, Laws of the State of New York, 1904, for "the advancement of the engineering arts and sciences in all their branches, and to maintain a free public engineering library " The Corporation was further empowered to acquire real and personal property and to use, maintain and occupy it, with the provision that any building erected by the Corporation shall be used perpet¬ually as a meeting place and headquar¬ters for the Founder Societies Thus the Carnegie gift realized the ideal of bring¬ing the engineering societies together under one roof, and the Corporation through its members nominated in equal numbers by the four Founder Societies had the necessary authority to act for the Founder Societies in their joint in¬terests in owning and operating for them not only Engineering Societies Building, but in the course of time, Engineering Societies Library, and The Engineering

Jan 1, 1952

By Dale R. Ralston, Roy E. Williams, Gerry V. Winter, George L. Bloomsburg

The term unsaturated flow refers to the conditions in which soil pores are filled partially with water and partially with air. This situation constitutes a porous material filled with immiscible fluids. Immiscible fluids by definition exhibit a distinct interface when in contact with each other resulting in a pressure discontinuity across the interface due to surface tension. The fluid that tends to wet the solid particles is called the wetting fluid and the other is the nonwetting fluid. In the air-water sys- tem, air is the nonwetting fluid and water is the wetting fluid. A somewhat analogous fluid system is that in a petroleum reservoir in which there may be up to three immiscible fluids-oil, salt water, and natural gas. The degree of wettability of the fluids is salt water + oil + gas. That is, salt water is the wetting fluid at any interface and oil is the wetting fluid at an oil-gas interface but is the nonwetting fluid at a water-oil interface. Since the oil-water and air- water systems are similar, much of the theory and methods of analyses for the air-water system or unsaturated flow have evolved through the petroleum literature. In the two-fluid system the pressure difference across an interface depends on the size of the pore space in which the interface occurs. The equation commonly used to represent this dependence is

Jan 1, 1986

ALTHOUGH the development of the various flotation processes during the last 8 years has been so revolutionary, this development has been, until recently, entirely confined to the separation of the gangue from the mixed metalliferous sulphides.The desirability of finding some method of separating the independent sulphides from such a miXture, by means of flotation, has long been recognized. ThIS need was emphasized when the slimes resulting from the grinding of Broken Hill sulphide ores were for the first time successfully dealt with by the Mineral Separation Company's process on the Central mine. This process proved the practicability of separating the sulphides of lead and zinc as a mixed concentrate from the gangue present in slime. Although this was a very notable achievement, the process has not been generally used, owing to the mixed lead and zinc concentrates resulting from the treatment being acceptable neither to the zinc nor the lead smelters.Although the introduction of eucalyptus oil in minute quantities as an emulsifying agent has simplified the work of the subsequent tabling of mixed sulphide concentrates, rendering unnecessary the burning off or removal of the oil, there will always be a considerable quantity of slimy product too fine to settle on the moving surface of the concentrating machines, and therefore requiring other means for its division into lead and zinc concentrates.

Jan 1, 1911

By Andrew H. Merritt

INTRODUCTION The prediction of the engineering behavior of a rock mass depends upon the systematic analyses of the results of an exploration program, and upon the recognition of the significant rock properties in the early stages of excavation. The variations in rock properties in different geologic terrains and the state of the geotechnical art preclude complete success in the former case, and we therefore must rely heavily on the experience gained in the latter phase. The geotechnical information obtained from these two phases is only of value to the design engineer when applied to the rock behavior during excavation and subsequent plant operation. Pertinent questions which must be answered include: how does the joint orientation and frequency effect tunnel support and overall cavern stability; how does the depth of surficial soil or weathering effect foundations or slope stability for portal cuts; are there permeable zones within the rock mass that could lead to leakage problems around penstocks and is the material in these zones soluble or likely to pipe in the long term; and does the proposed engineering structure fit the terrain, or will it inevitably lead to problems requiring extensive remedial treatment. During the early stages of construction there are two types of geotechnical information required; actual rock behavior with respect to the original design assumptions,

Jan 1, 1997

By John Cowin, Dan McCutchen

Cowin & Company has specialized in underground construction since 1924. This paper reviews the sinking of two shafts in the Alabama coal fields using bulk-loaded explosives. Each shaft is eighteen hundred feet deep, and their diameters were twenty feet and twenty-three feet. The first consideration in changing to a new explosives system was safety. Safety began with the explosive supplier training the miners in the use of the new system, from explanation of the pumping unit on the surface to hands-on training in the shaft. The considerations covered include establishing a thunderstorm exit plan, and reducing exposure time of the crew to explosives while loading. The system consisted of a specialized pumping unit and an advance emulsion product. Eliminating the need for nitroglycerin based explosives, and reducing sensitivity to mechanical shock were goals that were met. Performance in the shaft and ease of use meant morale of the miners using the system remained high and positive. Performance benefits discussed include reducing the number of holes in the round, and cutting explosives loading time in half. Damage to the ribs of the shaft was greatly reduced, making it safer to work near the ribs on succeeding rounds. Cleaning the bottom before drilling the next round also showed marked improvement. The economics of the system became very apparent when cycle time saved was allocated against fixed cost of sinking these shafts.

Jan 1, 2000

By S Miller, R Smart, J Thomas

Single-addition and sequential net acid generation (NAG) experiments were carried out on natural and prepared samples with varying contents of organic matter and pyritic S. Results show that carbonaceous matter can produce significant quantities of organic acids during peroxide oxidation in the NAG test, which leads to overestimation of acid-forming capacity and misclassification of benign samples as potentially acid forming (PAF). Organic matter effects were most pronounced in samples with low S (less than 0.5 per cent) and total organic carbon (TOC) contents of greater than seven per cent. The single-addition NAG test will tend to overestimate acid potential in samples with little or no pyrite and high organic matter content, potentially leading to sample misclassification. High pyritic sulfur samples tend to show little difference in single-addition NAG acidities with increasing organic matter, and it appears that pyrite is preferentially oxidised by peroxide when present in significant concentrations (greater than one per cent pyritic S). In sequential NAG tests overestimation was greatest in samples with little or no pyrite, but highly carbonaceous (>20 per cent TOC) pyritic samples were affected in later stages as the pyrite was depleted. A modified NAG method is proposed to account for the relative proportions of pyrite derived acidity and organic acidity in a given NAG solution.

Jan 1, 2003

By C. K. Leith

In discussing the subject of mineral exploration, one is tempted to resort to reminiscence. I could tell of many missed opportunities, but I propose rather to outline certain changes in the methods and conditions of exploration which present new problems to the mineral explorers of today. Our subject might appropriately be called The Passing of the Old Time Prospector. The first question that presents itself is whether the job of mineral exploration is not already pretty well finished. The current market surplus of most minerals and the present overcapacity for production, with their attendant financial troubles, naturally raise the question whether the accumulation of reserves has not gone far enough for the present, and whether further exploration should not be left to some future time when consumption shall have caught up. Unquestionably we have gone far in the conquest of our physical environment, and the fear of shortage of minerals is less than formerly. For the time being there is no great need of further supplies for the world as a whole of many of the great essential minerals, coal, oil, copper, zinc, silver, and others. For a few minerals, such as gold and lead, the known future world supplies are not yet large enough. For all minerals the distribution is so unequal among the nations that exploration will continue in deficient areas in the attempt to make nations self-supporting.

Jan 1, 1932

An evaluation was made of the wear and performance characteristics of liter bars, and the cost-life effectiveness of backing materials for rotary-mil liners. In a large run-of-mine mil in which the liter bars were mounted on grid liners of austenitic manganese steel (AMS), the liners had an average life that was five to six times that of equivalent unprotected liners. For a single mil, this is equivalent to annual savings in the cost of materials of up to R320 000, and to a downtime of 100 hours. Of the five materials tested in a large pebble mil grinding quartzitic ore, AMS grids and 'white iron' blocks performed best on a cost-life basis, with possibly improved performance from a real white cast iron. (The 'white iron' was shown by microstructural analysis to contain flake raphite and pearlite, being in reality a grey cast iron.) The high-chromium white iron had by far the longest predicted life, with mild steel a surprising second. Rubber was shown to last well in this type of mil. The wear rates of liners change during their lifetimes. The protective effect of liter bars was clearly illustrated by the reduction of over 40 per cent in the wear rates of the liners when the lifter bars were renewed to a height of 80 mm from a fully worn height of 35 mm.

Jan 1, 1991

By H. R. Ogden, E. S. Bartlett, A. G. Imgram

THE tensile and notch tensile ductile-to-brittle transition characteristics of several refractory metals and alloys have been well documented.1-3 Electron-beam melted tantalum and columbium have been shown to retain excellent ductility at very low temperatures. Some indications of brittle behavior (low ductility and cleavage fracture) were observed with columbium tested at -253oC, but no similar effects were noticed with tantalum. Increasing the interstitial oxygen content in these two materials resulted in the detection of indications of brittle behavior at higher temperatures, although good ductility was retained in both bases at -196°C when they contained about 1 at. pet 0. Detailed descriptions of the impact transition behavior of these two materials at various purity levels have not been available. This technical note describes the effect of interstitial oxygen on the impact properties of wrought, fibered tantalum and columbium and compares the transition behavior to the previously determined tensile transition characteristics. Tantalum and columbium impact specimens with three different interstitial oxygen levels indicated in Table I were tested at temperatures ranging from -196o to 300°C. Oxygen additions were made to 1/2-in.-diam bars of electron-beam melted material in a Seiverts Apparatus. The oxygenated bars were then homogenization-annealed to obtain uniform cross-section hardnesses and swaged to

Jan 1, 1964

By Takeshi Tanaka, Shinya Ono, Tsuyoshi Kato, Masaji Kato, Yuusaku Tominaga

The knowledge of the macroscopic characteristics of a ventilation network is of fundamental importance for taking counter- measures to increase air quantity in-specified branches, such as those corresponding to working faces at advancing entries or longwall panels. Because the ventilation characteristics are inherent properties of each mine, it takes a long time for an engineer to accumulate experience on how a specific regulator may affect the air quantity in a specific branch of a mine with a complicated ventilation system. A computer-simulation training system, based on the macroscopic ventilation characteristics, is presented in this paper. When a trainee selects a specific condition from five regulator option (closed, almost closed, slightly open, half open, open), the change in air quantity for a network branch is indicated by the color allocated to the ratio of the new air quantity to the old or planned air volume. After the ventilation simulation, the colors in the specified branches are defined by using the fuzzy set theory. The trainee continues practicing the selection of closed/open conditions for different regulators until each of the specified branches is displayed in good state of airflow. The ventilation net- work of the Horonai coal mine is used as an example of the training system to control air quantities in six working faces with 33 regulators.

Jan 1, 1996