Search Documents

Sec. 1. The membership of the Institute shall comprise six classes, namely: 1. Members; 2. Honorary Members; 3. Senior Members; 4. Associates; 5. Junior Members; 6. Rocky Mountain Members. All shall be equally entitled to the privileges of membership, excepting that no member of any class whom residence shall be outside of the United States of America, except those residing in Mexico and Canada, shall be entitled to vote. SEC. 2. Members: A person to be eligible for election or transfer into the claw of Member must be at least 27 years of age and must have had at least six years' employment in the practice of engineering, mining, geology, metallurgy, or chemistry, during at least three years of which he must have held positions of responsibility in one or more of these fields. This shall not apply to Rocky Mountain members.

Jan 1, 1939

SEC. 1. The membership of the 'Institute shall comprise six classes, namely: 1. Members; 2. Honorary Members; 3. Senior Members; 4. Associates; 5. Junior Members; 6, Rocky Mountain Members. All shall be equally entitled to the privileges of membership, excepting that no member of any class whose residence shall be outside of the United States of America, except those residing in Mexico and Canada, shall be entitled to vote. SEC. 2. Members: A person to be eligible for election or transfer into the class of Member must be at least 27 years of age and must have had at least six years' employment in the practice of engineering, mining, geology, metallurgy, or chemistry, during at least three years of which he must have held positions of responsibility in one or more of these fields. This shall not apply to Rocky Mountain members.

Jan 1, 1932

By Monique Nykamp

"INTRODUCTIONTerminal 46 is located just south of downtown Seattle, and is one of the Port of Seattle’s busiest container terminals. The Terminal 46 Redevelopment Project was undertaken to replace the existing 15-m-wide (50 ft) cranes along the apron with 30-m-wide (100 ft) cranes, which can unload larger, post- Panamax ships. The project included upgrading the existing waterside crane rail with new piles and constructing a new land-side rail behind the sheetpile bulkhead. The new piles had to be installed adjacent to the existing apron without causing damage, which was a signifi cant geotechnical challenge due to the soft soil conditions at the site. An instrumentation program performed during the test pile program evaluated this challenge and allowed for the development of specifi c production pile installation procedures that had the least possible effect on construction costs and schedule. SITE HISTORYThe site lies along the west side of Elliott Bay, north of the mouth of the Duwamish Waterway. Prior to development, this area was part of the tide fl ats where the Duwamish River drained into Elliott Bay. Prior to 1970, there were several existing timber piers and structures in the area. In the 1970s, the Port of Seattle constructed a 900-m-long (3,000 ft), 30- m-wide (100 ft) apron to support fi ve, 15-m-wide (50 ft) container cranes. The contained backland area was then fi lled with dredged spoils (sand and silt with organics) and the upper 5 to 20 m (16 to 65 ft) backfi lled with sand and gravel.The existing apron was constructed using 0.4 m (16 in) octagonal prestressed concrete piles to support the precast concrete deck and crane rails. The pile-supported bents were spaced at 6.1 m (20 ft), center-to-center, along the longitudinal direction. Pile lengths typically varied from about 20 to 40 m (65 to 130 ft) with 15 to 26 m penetration below mudline (50 to 85 ft penetration). The slope below the apron was constructed at about 1.75 horizontal to 1 vertical to allow for suffi cient water depth for cargo ships. In most areas, a riprap buttress was placed at the toe of the slope. A typical cross section of the apron is shown on Figure 2.Several stability, settlement and pile driving issues arose during the original construction of T-46 (Pita, 1983). Reportedly, movement of the submarine slope occurred during pile driving, resulting in settlement behind the bulkhead. Pile driving reportedly caused settlement of adjacent piles. In addition, some piles were “running” (dropping quickly under one hammer blow) during installation."

Jan 1, 2007

By Monique Nykamp

"INTRODUCTIONTerminal 46 is located just south of downtown Seattle, and is one of the Port of Seattle’s busiest container terminals. The Terminal 46 Redevelopment Project was undertaken to replace the existing 15-m-wide (50 ft) cranes along the apron with 30-m-wide (100 ft) cranes, which can unload larger, post- Panamax ships. The project included upgrading the existing waterside crane rail with new piles and constructing a new land-side rail behind the sheetpile bulkhead. The new piles had to be installed adjacent to the existing apron without causing damage, which was a signifi cant geotechnical challenge due to the soft soil conditions at the site. An instrumentation program performed during the test pile program evaluated this challenge and allowed for the development of specifi c production pile installation procedures that had the least possible effect on construction costs and schedule.SITE HISTORYThe site lies along the west side of Elliott Bay, north of the mouth of the Duwamish Waterway. Prior to development, this area was part of the tide fl ats where the Duwamish River drained into Elliott Bay. Prior to 1970, there were several existing timber piers and structures in the area. In the 1970s, the Port of Seattle constructed a 900-m-long (3,000 ft), 30- m-wide (100 ft) apron to support fi ve, 15-m-wide (50 ft) container cranes. The contained backland area was then fi lled with dredged spoils (sand and silt with organics) and the upper 5 to 20 m (16 to 65 ft) backfi lled with sand and gravel.The existing apron was constructed using 0.4 m (16 in) octagonal prestressed concrete piles to support the precast concrete deck and crane rails. The pile-supported bents were spaced at 6.1 m (20 ft), center-to-center, along the longitudinal direction. Pile lengths typically varied from about 20 to 40 m (65 to 130 ft) with 15 to 26 m penetration below mudline (50 to 85 ft penetration). The slope below the apron was constructed at about 1.75 horizontal to 1 vertical to allow for suffi cient water depth for cargo ships. In most areas, a riprap buttress was placed at the toe of the slope. A typical cross section of the apron is shown on Figure 2.Several stability, settlement and pile driving issues arose during the original construction of T-46 (Pita, 1983). Reportedly, movement of the submarine slope occurred during pile driving, resulting in settlement behind the bulkhead. Pile driving reportedly caused settlement of adjacent piles. In addition, some piles were “running” (dropping quickly under one hammer blow) during installation."

Jan 1, 2007

By H. R. Babitzke, H. Kato, R. E. Siemens, G. Asai

The purpose of this investigation was to develop a wide variety of columbium and tantalum alloys and to determine their suitability for use at elevated temperatures . Sixty - nine columbium and tantalum alloys were investigated . For this study , columbium was alloyed with two or more of the following : nium, tungsten , vanadium , titanium, and zirconium . Tantalum was alloyed with vanadium or hafnium, or hafnium and carbon . The fabricability was determined by an arbitrary procedure . Hardness measurements , elevated - temperature tensile properties , and oxidation- resistance studies were made . Of the alloys studied , Cb - 15 Hf - 5W, Cb - 15Hf - 5W- 10Ti , Cb - 15Hf - 10W- 10Ti , Cb - 10V - 5W, Ta - 30V , and Ta - 20 to 33Hf exhibited excellent high - temperature properties . These alloys were not only easy to fabricate , but they also had good oxidation resistance and excellent high- temperature strength .

Jan 1, 1964

By Jeff Schwoebel, Arcy, D&apos Horner

The Deep Coal Seam Project is a multi- year, large-scale research and development effort between the Gas Research Institute (GRI) and Resource Enterprises, Inc. (REI). The project is being conducted at the Red Mountain Site, a multi-well test site located in the southeastern portion of the Piceance Basin near Collbran in Mesa County, Colorado. The project objective is to develop the drilling, reservoir evaluation, completion and production technology required to produce gas from a thick, deeply buried coal seam. To understand the parameters controlling gas production, project efforts are focused on the Cameo "D" coal reservoir which lies at a depth of about 1707 m (5,600 ft) at the test site. This paper overviews the drilling, testing, completion, and production techniques used on the 1, 2 and 3 Deep Seam wells and implications for resource development.

Jan 1, 1987

By H. E. Parkinson, Y. P. Chugh

About 90 percent of the coal mined underground in the U.S.A. today is mined by the room-and-pillar system. The productivity of the system dropped from about 14,1t per man-day in 1969 to about 7,3 t per man-day in 1978. Since 1974, the U.S. Department of Energy (formerly the U.S. Bureau of Mines) has been engaged in research to improve the production and productivity of the room-and-pillar system. The effort involves the development of integrated, automated, and remote-controlled equipment and systems including remote-controlled continuous miners, automated miner-bolters, automated extraction systems, continuous haulage systems for use behind miners, and remote-controlled equipment for miners, bolters, and shuttle cars. These systems are discussed briefly, the discussion being related primarily to coal winning, although the concepts could be utilized in room-and-pillar systems in mines other than coal mines.

Jan 1, 1981

By Allen F. Agnew

Detailed stratigraphic studies in the Wisconsin-Illinois-Iowa district have made it possible to map the folds and faults that controlled the deposition of the zinc-lead ore. Prospecting on the basis of this mapping and prospecting in lower zones that are potentially ore-bearing have led to discoveries of ore. GEOLOGIC studies for the Federal and State governments in the Wisconsin-Illinois-Iowa zinc-lead district were begun in 1835, and subsequent surveys were made in the three states at intervals until 1916, see Table I. The current study of the district, Fig. 1, by the U. S. Geological Survey was begun in 1942 in the hope that a systematic investigation would help increase production of zinc and lead, then in extremely short supply. Major emphasis of the USGS program was on detailed mapping of the geologic structure and ore deposits. Preliminary maps and reports covering localities of intensive mining activity have been published during the course of this study, Fig. 2. By 1950 the objectives of the study by the USGS were revised; 71/2-min quadrangles of relatively unprospected localities as well as intensively mined localities are now being mapped in Wisconsin. Since 1945 the investigation in Wisconsin has been made in cooperation with the Wisconsin Geological and Natural History Survey, and since 1951 the geologic mapping of areas of particular interest in Iowa has been performed in cooperation with the Iowa Geological Survey. At intervals since 1943 the Illinois State Geological Survey has mapped the geologic structure and ore deposits of localities in the Illinois part of the mining district, see Fig. 2. Geology was applied by mining company personnel as early as 1853, but only sporadically, with periods of greater application between 1890 and 1925. Much of the so-called geologic work was in reality mining engineering. Since 1946 the major mining companies in the district have employed geologists who have successfully applied geologic techniques in the search for ore. History of Mining Occurrence of galena in the district was known as early as 1658 or 1659, when French explorers heard of lead mines that were apparently in the vicinity of Dubuque, Iowa. In 1690 a trading post was established near Dubuque to obtain galena. The first significant attempt at mining by white men took place in 1788 when the Indians granted to Julien Dubuque mining rights for 20 miles along the west side of the Mississippi River, including the vicinity of Dubuque, Iowa. By 1805 lead was being mined near Galena, Ill. In 1819 permanent settlement of the region was begun, and most of the important lead-producing areas had been found by 1830, see Fig. 3. Lead production in the Wisconsin-Illinois-Iowa district between 1830 and 1871 far exceeded that of any other district in the U. S.' Smithsonite was first mined in 1859, and sphalerite was mined as early as 1867. After 1873 the production of sphalerite exceeded that of smithsonite. In 1873 annual zinc production from the district first equaled lead production, and from then until 1893 production of zinc and lead was roughly the same. Since 1893 the ratio of zinc to lead mined has generally ranged between 5:l and 20:l. In 1942 the Wisconsin-Illinois-Iowa zinc-lead district ranked 14th among zinc-producing districts of the U. S. From 1946 until February 1953 the dis-

Jan 1, 1956

By Lala Zhao, Yuemin Zhao, Guangyuan Xie, Chusheng Liu, Chenlong Duan

"Screening is an important means of size classification used on granular or particulate materials. The vibrating modes of screen separator have a great effect on the screening process. Elliptical vibration mode is a complex motion mode which gets the common characteristics of both linear and circular vibration modes. However, the fundamental motion and screen penetration of the particles on the elliptically vibrating screen deck are still poorly understood. A numerical study of the motion of particulates flow along an elliptically vibrating screen deck is presented by means of a three dimensional Discrete Element Method (3D-DEM). The motion characteristic of the particle flow is analyzed at a particle scale. The effects of vibration amplitude, throwing index, vibration direction angle and screen deck inclination angle on the screening process are discussed. The results show that the particles average velocity increases linearly with the increase of vibration amplitude, throwing index and screen deck inclination angle, but decreases linearly with the increase of vibration direction angle. The screening efficiency is highest when the vibration amplitude, throwing index, vibration direction angle and screen deck inclination angle are 4.5 mm, 3.3, 40° and 6°, respectively. This work is helpful for developing a deep understanding of particle motion on the elliptically vibrating screen and for optimizing screen separator designs."

Jan 1, 2014

By Harry Verakis, Thomas Lobb

This paper is a summary and an update of the underground mine blasting accident investigations and studies previously conducted by the Mine Safety and Health Administration (MSHA) and the former US. Bureau of Mines. Blasting accidents are usually a small percentage of the total number of mining accidents. However, blasting accidents continue to occur and the severity of these accidents is disproportionately high with respect to other types of mining accidents. In 2000, about 5.7 billion pounds of explosives were produced in the USA. The mining industry consumed the greatest portion of explosives manufactured for blasting with about 67 percent used for coal mining. Metal and nonmetal mining operations account for about 23 percent of the use of explosives. The use of permissible explosives in underground coal mines continues to decline (3,373,069 pounds for 2000).

Jan 1, 2002

By R. Sakthivel

Blue dust is a high grade soft haematite material containing 96.14% Fe2O3 transformed into magnetite (Fe3O4), when it is subjected to planetary ball milling in the presence of iron powder as reducing reagent. X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM) and Laser particle size analyser have been employed to characterize various samples collected at various milling times to know the phase evolution, particle size distribution and morphology of particles. X-ray diffraction studies reveal the formation of magnetite phase at the optimum milling time of 40 hours. Vibrating sample magnetometry (VSM) study demonstrates, that sample obtained at 40 hours of milling time exhibits saturation magnetisation of 14.757 emu/g whereas the starting material used in this study shows only 1.0425 emu/g. Keywords: Blue dust, reaction milling, magnetite, saturation magnetization

Sep 1, 2012

By John C. Branner

Five of the geologic horizons that yield oil in other parts of the world are represented in Brazil; namely, the Devonian, Carboniferous, Permian, Cretaceous, and Tertiary. Thus far, the first two have shown no evidences of being oil bearing within Brazilian territory. Not enough exploring has been done to permit trustworthy comparisons of the relative importance of the Permian, Cretaceous, and Tertiary as oil-bearing horizons in this country. The most important, indeed almost the only, information available relates to the locations of the areas and to the structural features of the several horizons. The theories regarding the physical conditions under which these rocks were laid down, however, I regard of the utmost importance. Permian Rocks of Permian age cover an enormous area in Brazil, extending from Rio Grande do Sul to Maranhao on the north, and to Matto Grosso on the west. These Permian rocks in many places are known to include oil-bearing shales and in some locations contain small veins of gilsonite. The geologic map of Brazil shows that the Permian area is widely distributed, but there is considerable doubt about the origin of some of the rocks. Some of the lower Permian beds in southern Brazil contain marine fossils, but in Minas no fossils have as yet been found in them, and in Bahia, at only one locality have a few Permian plants been found. Indications of oil have been found in the states of Sa0 Paulo, Parana, and elsewhere farther south, but wells drilled in the Permian of SaO Paulo near the Morro do Bofete did not find oil. One well has been started, by the Brazilian Government, in the Permian of Parana near Marechal Mallet, close to latitude 26" south, but thus far oil has not been found.

Jan 1, 1923

By John C. Branner

Five of the geologic horizons that yield oil in other parts of the world are represented in Brazil; namely, the Devonian, Carboniferous, Permian, Cretaceous, and Tertiary. Thus far, the first two have shown no evidences of being oil bearing within Brazilian territory. Not enough exploring has been done to permit trustworthy comparisons of the relative importance of the Permian, Cretaceous, and Tertiary as oil-bearing horizons in this country. The most important, indeed almost the only, information available relates to the locations of the areas and to the structural features of the several horizons. The theories regarding the physical conditions under which these rocks were laid down, however, I regard of the utmost importance. Permian Rocks of Permian age cover an enormous area in Brazil, extending from Rio Grande do Sul to Maranhao on the north, and to Matto Grosso on the west. These Permian rocks in many places are known to include oil-bearing shales and in some locations contain small veins of gilsonite. The geologic map of Brazil shows that the Permian area is widely distributed, but there is considerable doubt about the origin of some of the rocks. Some of the lower Permian beds in southern Brazil contain marine fossils, but in Minas no fossils have as yet been found in them, and in Bahia, at only one locality have a few Permian plants been found. Indications of oil have been found in the states of Sa0 Paulo, Parana, and elsewhere farther south, but wells drilled in the Permian of SaO Paulo near the Morro do Bofete did not find oil. One well has been started, by the Brazilian Government, in the Permian of Parana near Marechal Mallet, close to latitude 26" south, but thus far oil has not been found.

Jan 1, 1923

By J. M. Campbell, T. S. Buxton

The most widely used methods of predicting the volumetric properties of gas are based on the principle of corresponding states, which asserts that the compressibility factor is a universal function of reduced temperature and pressure. Previous studies have shown that the acentric factor, as proposed by Pitzer, l is an important addition to reduced pressure and reduced temperature as factors affecting the compressibility factor. Results of this study indicate that, if the pseudocritical temperature and pressure used to determine the reduced conditions are adequately predicted, characterization of natural gas-carbon dioxide mixtures with the acentric factor will allow reliable determination of the compressibility factor. Comparisons of predicted and experimental compressibility factors have shown that the pseudo-critical constant rules of Stewart, Burkhardt and Voo 2 are satisfactory for hydrocarbon mixtures. However, these rules fail to predict the pseduo-critical constants for hydrocarbon-carbon dioxide mixtures. Based on graphically determined pseudocritical temperatures for binary hydrocarbon-carbon dioxide mixtures, a correlation which gives the required correction to the Stewart, Burkhardt and Voo rules was prepared and a compressibility factor prediction technique was proposed. To test the proposed technique, compressibility factors for live mixtures of methane, carbon dioxide and either ethne or propane were experimentally determined at 100, 130 and 160F and pressures up to 7,026 psia. The predicted and experimental compressibility factors for these live mixtures had an average absolute deviation of 0.55 percent. INTRODUCTION Two-parameter generalized correlations based on the principle of corresponding states (PCS) are presently available for reliably predicting the compressibility factor of lean natural gas, i.e., natural gas with low concentrations of hydrocarbons heavier than methane. When these same correlations are used for mixtures of natural gas and carbon dioxide, large deviations between actual and predicted compressibility factors are observed. This study was undertaken to provide a means for accurately predicting the compressibility factor for such mixtures. In the past, two avenues of approach have been employed to extend the applicability of the PCS. The first has been to introduce additional parameters. The second has been to develop combination rules for predicting pseudocritical constants which do not suffer from the limitations of the commonly used molal average constants. In this study, both of these approaches have been considered and employed to arrive at a method for predicting the compressibility factor of mixtures of hydrocarbons and carbon dioxide. SELECTION OF A THIRD PARAMETER Failure of the original PCS to predict the compressibility factor for all pure gases, regardless of their mass, shape or polar moment, has led to the introduction of additional parameters into the PCS. Parameters have been introduced to correct for quantum deviations,3-5 non-spherical or globular shapes6-9 and for polar moments.8-12 In addition to these parameters which are based on some microscopic property and intended to correct for some specific cause of deviation, more general parameters based on some bulk property have also been introduced.1913-16 To use additional parameters to correct for each of the possible causes of deviation among the individual constituents of a gas mixture would require a rather complex form of the PCS. To maintain the PCS in as simple a form as possible, it is more desirable to have a single third parameter which is based on some bulk property influenced by several of the factors causing deviations. The third parameter selected for use in this study is a factor originally proposed by Pitzer.9

Continuous improvement has become the watchword of the 1990s for most iron-ore-processing operations. In many instances, this improvement has been achieved through stepwise application of advanced control techniques to optimize operations. The benefits of this stepwise application have been great. However, they have fallen short of the full potential offered by the prospect of overall plant optimization. The successful integration of computers, instrumentation and control software throughout a plant promises to deliver an additional 3% to 5% of productivity in even the best-run plants (Herbst and Bascur, 1984). LKAB is Europe's largest iron-ore producer and a leading implementer of advanced control technology. In the late 1980s, LKAB introduced advanced control in its concentrator at Kiruna, Sweden to improve plant performance through higher productivity, greater efficiency and lower costs at each processing step.

Jan 1, 1995

By L. D. Mullins, H. B. Bradley

Numerous articles have appeared in the literature citing the application of the potentiometric analyzer to cycling operations. Specific information obtainable by a potentiometric analysis, as noted by various investigators, includes: 1. Pattern sweep efficiency for various injection and production rate programs. 2. Injected fluid breakthrough time at production wells. 3. Optimum production and injection rates. 4. Prediction of injection and/or production well locations. 5. History of advance of the in-jected-produced fluid interface. 6. Ultimate life of the reservoir. 7. Ultimate reservoir production. This note describes a procedure for predicting pressure distribution in a gas-condensate reservoir by using the potentiometric analyzer to obtain potential distribution data on an analog model of the reservoir and then applying Muskat's' equations. The method relates the volumetric weighted average datum pressure to the mean potential in the model.

Jan 1, 1958

The papers discussed in the following pages were presented during two sessions of the Geophysics Education Committee of the Mineral Industry Education Division on Feb. 17 and 18, 1941. At the first meeting, to consider the "Influence of Geophysics upon Geology Curricula," this Committee was joined by the Geophysics and Mining Geology Committees of the A.I.M.E., the Society of Economic Geologists, representatives of the American Geophysical Union, and delegates from the Committees on College Curricula and on Applications of Geology of the American Association of Petroleum Geologists. Quentin D. Singewald and Sherwin F. Kelly presided. At the ensuing session, especially emphasizing the integration of geology, physics and chemistry for the solution of earth problems, the joint participants with the Geophysics Education Committee were the Geophysics Committee, and representatives of the American Geophysical Union and of the Committee on College Curricula of the American Association of Petroleum Geologists. Richard M. Field and W. R. Chedsey presided. In the following summary of the discussion at the two meetings, written discussion submitted subsequently is not differentiated from that offered orally at the session. A provisional report of the Geophysics Education Committee was presented at the second session, and some of the following discussion refers to it. This report has not been printed (it is anticipated that a more comprehensive, final one will be rendered at the 1942 annual meeting), but a few mimeographed copies of this provisional report are at the A.I.M.E. headquarters and will be mailed on request. . Dr. W. P. HAYNES presented some notes prepared by Dr. F. H. LAHEE, Chairman of the American Association of Petroleum Geologists' Committee on College Curricula. This Committee's inquiries reveal the general opinion that a four-year academic preparation is inadequate, five or six being advisable. The fundamentals, mathematics, physics, chemistry, and English composition, should be stressed in the first three years, with specialization in the last two or three years. Some companies provide an apprenticeship period, and themselves give additional training.. During academic years more attention needs to be given to engineering training, to field mapping, and in geology to stratigraphy and sedimentation. The amount of mere memory work should be cut, and men trained to observe and reason. Dr. Lahee emphasized the need of more adequate preparation in English composition, because of the inability of many graduates to compose acceptable reports. SHERWIN F. KELLY pointed out that much time in university training, which ought to be devoted to technical subjects, was taken up with English courses. He emphasized that it is the part of the universities to demand of the high schools that the students they send to the university be properly trained to speak and write English. Prof. W. T. THOM protested against the crowding of high-school material into already overcrowded college curricula. C. E. DOBBIN, chairman of the Committee on Applications of Geology of the American Association of Petroleum Geologists, described briefly the work of his committee in publicizing geology, and said that it found a widespread popular interest in the subject but a lack of appreciation of its importance. He recommended that attempts to coordinate the works of geologists and geophysicists be expanded somewhat, toward the further developing and encouraging of a "species of geopolitician" capable of assisting the progress of geology and geophysics by more vigorous advertising of

Jan 1, 1941

By K Williams

Marvel Loch South Pit has had a number of stages of open and underground mining activities before acquisition by Sons of Gwalia. The historical pit had achieved a completed pit depth of 150 metres and the shaft and decline mine had reached approximately 220 metres in depth using open stope mining methods. The various mining methods reflect the various economics and industry practice at the time. The South Pit ore zones are medium grade (~2.5 g/t) but have a regular geometry and large tonnes per vertical metre. A number of studies have been completed up to a pre-feasibility stage looking at options to extend the pit depth and to lower the unit cost of gold production. The options considered were the re-optimisation of the pit to determine further cutbacks or the innovative use of an in-the-wall ramp. The in-the-wall ramp (tunnel) would permit the removal of the in pit ramp to expose additional ore that was within the footprint of the ramp design and to provide the opportunity to increase the final pit depth. Similar mining method has only been used at Three Mile (Coolgardie, WA) and Chalice Mine (Norseman, WA). The tunnel would serve as a gateway for further extension of the south mine and the central ore zone via underground mining methods. The ultimate depth of the South Pit has been extended to 310 metres below surface and significant additional ore has been recovered. This paper will give an insight into the various studies to optimise the Tunnel mining method, the determination of the various tunnel dimensions, and the phases of mining to arrive at the completed design.

Jan 1, 2003

An extensive ferromanganese nodule field south of New Zealand (Fig. 1) has existed beneath the flow of the Deep Western Boundary Current (DWBC) and Antarctic Circumpolar Current (ACC) for at least the past 15 m.y. West of 174°E, between 59°S and 48°S, the field is 300-500 km wide, but east of 174°E, where current flow impinges on the eastern slope of the Campbell Plateau, the field narrows from ca. 200 km at 55°S to ca. 120 km at 51°S. This narrowing coincides with deflection of current flow eastwards, and consequent reduction in bottom-current velocity and eddy kinetic energy. Based on sea floor photographs, dredge samples and 3.5 kHz profile data, six distinct seafloor substrates are delineated, forming broadly parallel zones eastwards from the lowermost Campbell Slope (Fig. 2).

Jan 1, 2003

By M. Nagamori, A. J. Plumpton

"Commercial HCl-leaching of magnesite and serpentine yields highly concentrated aqueous solutions containing 25 mass % to 33 mass % MgCl2. The partial molar enthalpies and heat capacities, the ionic activities of Mg2+ and Cl–, and the Raoultian activity of H2O have been assessed for the concentrated MgCl2-H2O solutions at temperatures of 348 to 373 K. These thermodynamic data are used to calculate the pH of aqueous MgCl2 solutions saturated with a Mg-bearing mineral such as magnesite, serpentine, brucite, forsterite, enstatite or talc. On the basis of these thermodynamic data, technico-economic aspects are discussed as to neutralization with pulverized MgCO3, water evaporation from the MgCl2 solutions, and ore composition including such minor constituents as CaCO3, FeCO3 and Fe3O4. IntroductionA major magnesium electrolytic reduction plant operates in Quebec, where another will begin its production in the year 2000. One uses imported magnesite ore as raw material, while the other will utilize local asbestos tailings (serpentine). Both processes produce a concentrated salt solution of 25 mass % to 33 mass % MgCl2 by leaching the ore with concentrated hydrochloric acid. Thus, the two processes differ mainly in the HCl-leach and related operations. After the HCl-leach of the ore, the serpentine process yields about 25 times more wet cake to filter and wash than the magnesite counterpart. A comparative cost-engineering study with respect to slurry filtration and cake washing has been published elsewhere (Blackburn and Nagamori, 1994). By contrast, the present study considers the thermodynamics and technicoeconomics of the HCl-leach itself for both ores."

Jan 1, 1999