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By Shailin Lalloo, Allan B. Nesbitt

A fluidised bed was exposed to high gravities by placing it in a centrifuge. The bed expansions were measured and compared with the bed expansions predicted by the Richardson-Zaki model (1954). The Richardson-Zaki model was found to predict effectively the fluidisation behaviour of defined particles in this increased gravity environment.

Jan 1, 2003

By Shailin Lalloo, Allan B. Nesbitt

"Gravity separation by centrifugal equipment, particularly in the mineral processing industry is a novel approach of optimising product recovery. The manufacture and sale of centrifugal equipment by recently established companies is now beginning to have a significant impact on the industry. Some benefits of operating at increased gravity include: reduced environmental issues, a shorter lead time, lower capital cost and improved recoveries of elemental mineral before entering the grinding circuit.Of topical discussion is the use of centrifugal separators for the recovery of less valuable minerals that will form a greater proportion of the feed compared to traditional scalping circuits where the gold content is extremely low. This ultimately results in the centrifugal system having to have a greater mass pull. In addition, the relative density difference between gangue and valuable mineral is likely to be less and therefore modelling and optimisation of this separation process will be necessary. Some researchers have muted using fluidisation models to model the forces present in the separation zone of a centrifugal separator2. It is not unusual for the manufactures of centrifugal separation equipment to use fluidisation terminology to describe what happens in the separation zone. Most fluidisation models are based on the empirical/classic relationship between superficial fluid velocity and voidage postulated by Richardson and Zaki. However, no researcher has proved the effectiveness of this relationship in an increased gravity Environment."

Jan 1, 2003

By John M. Marek, David E. Nicholas

INTRODUCTION The purpose of this article is to outline the data requirements for selecting a proper underground mining method and to discuss the general steps taken in selecting that method. Determining the appropriate mining method is an iterative process that continues throughout the life of a mineral deposit. We will discuss the subject from the standpoint of a feasibility study, where a realistic assessment is necessary in order to determine investment merit. The feasibility stage of a project is that point where the drilling program has defined sufficient geologic reserves to consider mining the deposit but little or no underground development has been done. Primary parameters for consideration in choosing a mining method are 1) geometry of the deposit; 2) distribution of grade; 3) rock mass strength for the deposit, as well as the hanging wall and footwall; 4) mining cost and capitalization requirements; 5) mining rate; 6) type and availability of labor; 7) environmental considerations; and 8) other site-specific conditions. Of these parameters, the first four have the most impact on determining the general mining method to be employed.

Jan 1, 1981

Gold deposits in Eastern China have characteristic of belted distribution. The concentrating belts of gold mineralization are about parallel to the island are belt in Western Pacific Ocean. Gold deposits are mainly concentrated in the aged metamorphic rock series on the upwarping zones and upwarping fault zones, and obviously controlled by the deep fractures and their deriva-tive secondary faults. Gold mineralization had genetic relation to the Mesozoic (especially Yanshan period) magmatic activity. The distribution and genesis of gold deposits can be explained by the assumption of wavy structure. The formation of wavy structure is related to the process of Pacific plate and India plate.

Jan 1, 1990

By J. J. Forbes

THE Federal Coal Mine Safety Act (Public Law 552, 82nd Congress) was approved on July 16, 1952. It incorporates, as Title I, the Coal Mine Inspection and Investigation Act of May 7, 1941 (Public Law 49, 77th Congress), which gave Federal inspectors only the right to enter coal mines for inspection and investigation purposes but no power to require compliance with their recommendations. Title II contains the enforcement provisions of the act; its purpose is to prevent major disasters in coal mines from explosions, fires, inundations, and man-trip or man-hoist accidents. At this point a brief account of events that pre- ceded the enactment of the Federal Coal Mine Safety Act seems appropriate. The hazardous nature of coal mining was recognized by the Federal Government as long ago as 1865, when a bill to create a Federal Mining Bureau was introduced in Congress. Little was done, however, until a series of appalling coal- mine disasters during the first decade of this century provoked a demand for Federal action. As a result an act of Congress established a Bureau of Mines in the Department of the Interior on July 1, 1910. The act made it clear that one of the foremost activities of the Bureau should be to improve health and safety in the mineral industries. One of the first projects selected by the small force of engineers and technicians then employed was to determine the causes of coal-mine explosions and the means to prevent them. By investigations after mine disasters the fundamental causes and means of prevention were soon discovered, and the coal mining industry was informed accordingly. However, despite this knowledge and the enactment of State laws and the Federal Coal Mine Inspection and Investigation Act of 1941, mine disasters continued to occur with disheartening frequency and staggering loss of life. The devastating explosion at the Orient No. 2 mine on December 21, 1951, resulted in the death of 119 men. The Orient disaster rekindled the memory of the Centralia, I11., disaster of March 25, 1947, which caused the death of 111 coal miners. These two tragedies ultimately brought about enactment of the Federal Coal Mine Safety Act.

Jan 1, 1954

By AIME AIME

ORGANIZATION of The Federated American Engineering Societies was effected at the organizing conference of national, local, state and regional engineering and allied technical organizations at the Cosmos Club, Washington, D. C., June 3 and 4. Thus is brought into being the greatest national engineering society in the world. The object of the organization is to further the interests of the public through the use of technical knowledge and engineering experience, and to consider and act upon matters common to engineering and allied technical professions. Prominent engineers from all parts of the country, representing more than 75 engineering societies, with an aggregate membership of more than 125,000, participated in the organization. The constitution as adopted by the conference, calls for the creation of s managing body to be known as the American Engineering Council, and its executive board. The belief was expressed that the entire organization would come to be spoken of as the American Engineering Council. The council is to coordinate the activities of state councils and of local affiliations whenever these activities are of national or general importance or may affect the general interests of engineers. Representation in the council is to be according to membership of the component societies.

Jan 1, 1920

The Federation of Societies of Professional Engineers Our Institute is a member of the Federation and, to give members some idea of the work of the latter body, a few notes are submitted from the Federation's annual report for the year ended June 1973.

Jan 2, 1974

By K. E. Barrett

Exxon owns a uranium mill and holds two mining leases in Live Oak County, Texas, about halfway between San Antonio and Corpus Christi. The properties make up the Felder Uranium Operations which was reopened earlier this year. Exxon held an oil, gas, and other minerals lease on the J. C. Felder tract, which was adjacent to a relatively shallow uranium discovery by Susquehanna-Western, Inc. on the Marrs-McLean lease immediately south of the Felder property. Drilling in 1967 and 1968 confirmed the presence of reduced uranium mineralization in the basal sand unit of the Oakville formation on the Felder tract, which formed the major part of the roll-front deposit. In 1969 Exxon and Susquehanna-Western, Inc. entered into a sale and purchase agreement which provided for Susquehanna to mine and process Felder ore and purchase recovered uranium. Susquehanna moved an alkaline-leach mill from Wyoming, erected it on the Ray Point property, and placed it into operation late in 1970. Susquehanna mined and processed ore from the Felder and McLean properties through March 1973. Susquehanna ceased operations in March 1973. Exxon then acquired the mill and mill property. Exxon also purchased the mineral rights to the McLean lease, re-negotiated a mining lease for that property, and carried out shut-down programs for the mining and mill areas in the fall of 1973. The project was put on a standby basis until late 1973, when Exxon initiated mine feasibility studies for the project. MINE PLANNING EVALUATION The feasibility study for reopening the Felder Project began in late 1975 and was not completed until late 1976. I will discuss several areas of the feasibility study that required additional work prior to making the decision to renew operations. Ore Reserves Preparations for estimating the ore reserves began with the re-evaluation of more than 1500 natural radioactivity logs from exploration and pre-development drilling that had been completed on the property. These gamma ray logs of non-core rotary drill holes were the principal source of data used in making the estimate. Chemical assays of cores from the deposit were also used in the reserve determination. Electric resistivity and self-potential logs were made along with the gamma ray log. In December 1975 an additional core drilling project was undertaken to confirm the in-place density and radiometric equilibrium characteristics of the ore deposits. Comparison of chemical assays of cores with the U308 values calculated from the logs showed that the unoxidized ores were in radiometric equilibrium. In contrast, cores from anomalies occurring in near surface, weathered, and oxidized zones were in radiometric disequilibrium. Several important decisions were made in developing a mine plan or schedule of production from the Felder and McLean ore bodies. Disposal of Produced Mine Water: The ore bodies of the Felder Uranium Project occur at a point below the ground water table. The ore zones to be mined must first be dewatered to allow removal of mineralized material. In the open pit operations, this is accomplished by maintaining a perimeter ditch around the periphery of the open pit, allowing the interior of the pit to drain and collect into a sump and be pumped from the mine. In addition to anticipated water production from future mining operations, approximately 200M gallons of water was contained in three open pits left from prior mining operations. In two of these existing pits, the water was to be removed and disposed to allow for planned backfilling of waste material into these pits. The third pit would also have to be drained to allow continued mining of an area left from the prior operations. Essentially no ground water information was available for this area. The only data available was water production history from Susquehanna's mining operation. Two water wells were drilled early in 1976 on the Felder lease for use in obtaining hydrological data. A long term draw-down test was performed by pumping one water well and measuring water level drawdown in both the pumped well and the observation well. From these data, values for permeability and storage coefficient were calculated. These data were then used in modeling the aquifer to allow calculation of water influx into the mining area versus time. Once a schedule of water production, including the stored volume in the existing pits was calculated, alternate solutions for disposal were evaluated. The first system evaluated was a series of deep injection wells. The wells were designed to inject at a depth of approximately 3500 feet. Again very little information concerning reservoir characteristics of the receiving sand units was known. Using assumed values for reservoir permeability and storage coefficients, an injection well system was designed to allow for disposal of produced mine water. The biggest

Jan 1, 1979

By J. Philip Neal

Feldspar is no example of special mineralization in isolated spots: it can usually be found within a mile or so of almost anywhere. Along with silica sand, it is a major part of our world's total mineral composition. This fact imparts to it an economic status different from a sulfide ore, or potash, or phosphate. While every feldspathic "stringer" does not possess economic potential, the generous distribution does yield a high statistical frequency of good feldspar ore bodies: the adjective "good" being subject to some flexibility of interpretation. The strong chemical bonds of this alkali aluminum silicate give it certain use advantages, but under present technology its individual elements cannot practically be separated to create aluminum, potassium, sodium, silicon - or their oxides. Its present uses rely upon chemical inertness - as in fillers; and on its physical melting characteristics and their effect in glass, enamel, or ceramics.

Jan 1, 1973

Portman Mining Pty Ltd very successfully operated the Ferro GullyNorth Mine in the Hamersley Province of Western Australia to satisfy a contract for the delivery of six million tonnes of iron ore in less than two years to the Mount Newman Mining Co Pty Ltd. The high-grade ore extracted from Ferro Gully North Mine was unusual in that, not only was it within the Joffre Member of the Brockman Formation, but it was rich in red ochreous hematite and martite and very low in phosphorus.

Jan 1, 2001

By Louis A. Carapella, Ralph Hultgren

WHEN F. Heusler1 found in 1898 that certain alloys containing only copper, manganese, and tin were ferromagnetic, the discovery excited a great deal of interest and led to numerous investigations. It was early found that tin could be replaced by aluminum, arsenic, antimony, bismuth, or boron without destroying the ferromagnetic nature of the alloys.2 Copper may also be replaced by silver.3 All these alloys have come to be known as "Heusler alloys." The aluminum alloys apparently were the most magnetic and have been most extensively investigated. However, no agreement has yet been reached as to the source of the ferromagnetism arising from these nonferromagnetic elements. Absence of reliable quantitative data makes speculation hazardous. The value of much of the earlier work was vitiated by lack of necessary precautions against contamination, and by lack of close control of heat-treatment. It was only recently established that in aluminum Heusler alloys" the ferromagnetism arose from a single phase, an ordered body-centered-cubic structure. With modern methods of preparation, heat-treatment, and X-ray examination, it is possible to prepare these alloys without contamination, to heat-treat them intelligently, and to determine what phase or phases are present in the finished sample. In the present investigation, a series of pure alloys in the comparatively neglected copper-manganese-tin system have been prepared, which consist of a single, body-centered-cubic structure (the beta phase) and whose compositions vary within wide limits. The magnetic saturation values of these single-phase alloys have been quantitatively determined, so that considerable data on the effect of composition on the ferromagnetism have been made available. In the course of the investigation some information on the extent of the stability of the beta phase and the nature of phases in adjacent regions of the ternary diagram has been accumulated. Anomalies in earlier data have been explained, and alloys have been prepared that are much more strongly magnetic than any previous Heusler alloys. PREVIOUS WORK In the original work of F. Heusler1 and coworkers,2 a maximum magnetic saturation value of I = 107 was found at the composition Cu6Mn3Sn, while a value for Cu2MnA1 of I = 443 was early measured. Ross and Grays found a second maximum at the composition Cu2MnSn, which was much more magnetic than Heusler's original alloy. F. Heusler6 then reinvestigated the system, confirmed their results,

Jan 1, 1941

By I. H. Keith

INTRODUCTION The following papers describe the extraction of nickel in the form of ferronickel from the Dominican laterites. The Falconbridge process was developed initially in the Falconbridge Metallurgical Laboratories and subsequently in several successive stages of pilot plant operation in the Dominican Republic. In the course of this work we came to believe that there is advantage in piloting on site. Mining, metallurgical and geo-political considerations all have major impact and that belief has been borne out by commercial plant experience. Lateritic nickel ores differ substantially, even within the same orebody, in their amenability to extraction methods. The Falconbridge process takes account of the heterogeneous nature of the deposit. Three years of geological field exploration led to ten years of process development after it was realised that the then known metallurgical processes would not give economical extraction from the Dominican ores. In addition to establishing the viability of a novel pyrometallurgical approach, it was necessary to verify design parameters for a very considerable scale-up to prototype commercial operation. The plant was eventually constructed within the original estimates of time and cost. Unique features contributing to the technical and commercial success of the project are described. Additionally, some bold extrapolation based on pilot plant work, eventually proved to be quite conservative. The mine is not a conventional open pit operation, but is perhaps better characterised as an earth moving job. Novel application of mobile equipment led to great flexibility in the mine, where operation of several mining fronts is essential to maintaining uniformity of ore feed to the plant. The practical aspects of almost total acceptance of the oversize run-of-mine material through a high-capacity unit,

Jan 1, 1979

By R. B. Sosman

INTRODUCTION IT is well known that ferric. oxide, Fe.-,03, is paramagnetic, while magnetite, Fe304, is classed among the highly ferromagnetic substances. But magnetic data on oxides intermediate in composition between Fe-03 and Fe304 have been almost completely lacking. Fe203 and Fe304 form a solid-solution series, according to present evidence.' In this series the properties change continuously from Fe203 toward Fe304, as the percentage of FeO increases from zero toward 31.03, which is the percentage in magnetite. It is possible that there is a break in the series near Fe304, but it has not yet been possible to establish the existence-of such a break experimentally. The occurrence of solid solution ill this series is shown by the dissociation pressure, or oxygen pressure in equilibrium with the oxides, which falls continuously over the range from Fe203 to Fe304. The oxygen-pressure curves at 1,100° and 1,200° are shown in Fig. 1. The existence of solid solution is also demonstrated by the continuous change in optical properties from Fe203 over to a composition containing about 18 per cent. FeO, at which point the opacity of the oxide becomes so great that it is im-possible to obtain measurements at higher percentages of ferrous iron. Natural oxides of iron intermediate in composition between Fe2O3 and Fe304 are much more common than is generally supposed. If a mineral oxide is not strongly attracted by a small hand magnet and if it gives a red streak, it is usually labeled "hematite." If it is strongly attracted by the hand magnet it is usually labeled "magnetite" without further tests. As we shall show later, oxides containing from 1 up to 31 per cent. FeO can be thus erroneously lumped together as "magnetite." It is a fact, nevertheless, that the great hulk of natural oxides of iron lie fairly near either Fe203 Or Fe304 in composition. The reason will be

Jan 6, 1917

"Every year during the Transportation Research Board (TRB) Annual Meeting in Washington D.C., the Federal Highway Administration (FHWA) National Geotechnical Team (NGT) takes time to talk about what we are doing in research, training development and policy support. At times, I have jokingly referred to it as the State of the Program Address, but we do see it as an important opportunity to update our transportation partners on priorities and needs for the program.This update is really a snapshot of the program during the previous year, with a look at projects that are currently active. Activities undertaken by the NGT are funded from multiyear roadmaps maintained by the FHWA program and research offices, and reflect trends and opportunities affecting and influencing transportation geotechnics now and in the future. The roadmaps identify activities in research, development, guidance, technology transfer and training that will be accomplished by the NGT through and beyond FY 2020 in eight broadly-defined focus areas: • Extreme events, geohazards and sustainable geotechnics• Performance management• Reliability-based design and construction• Advanced geotechnical modeling• Alternative delivery methods• Design and construction optimization• Site characterization• Quality assuranceThe process to identify focus areas and to develop activities that will be addressed by the NGT is guided and informed through input from the FHWA NGT members, and considers feedback and input from State Departments of Transportation (DOTs), FHWA Division offices, industry and academia. This process is revisited annually to review not only the activities that are currently funded, or will be funded, but also to review the relevance of the focus areas with respect to the future needs of the FHWA, State DOTs and the transportation community.In 2016, the NGT was successful in delivering several products that will advance the state of the practice and that better support policy. Products developed included research reports, design and construction guidance, and training courses. In 2017, the research and program offices will continue to work on projects that fit within our prioritized plan and that positively impact the geotechnical community as a whole. A listing of recently completed and currently active projects is provided below."

Jan 1, 2017

By Rob Farnfield, Charlie Adhock

The measurement of near-field shock has always been an attractive proposition for those working in the field of explosive and blast performance. The most commonly employed technique involves the use of piezoelectric accelerometers. Although highly effective, these complicated devices are relatively expensive and are often destroyed in the blast event. This paper describes the development and field-testing of a shock sensor of sufficiently low cost to enable it to be routinely used in product blasting. This new device is based on piezoelectric wafer technology and does not require any external signal conditioning. The device is housed in a small cylindrical package with approximate dimensions of 30mm (1.2”) length and 5mm (0.2”) diameter. It has been determined that the most effective way of fixing the device to rock is in a small diameter hole with epoxy glue. Alternatively the sensor can be simply placed in holes filled with either water or bulk emulsion explosive.

Jan 1, 2005

By Cameron A

In recent years there have been significant developments in the tech- nology available for blast monitoring, analysis and simulation. Progress in these areas has been achieved through research conducted by explo- sives manufacturers and independent research groups from universities and mining companies. Miners are increasingly keen to exploit this tech- nology to help them design blasts which make optimum use of explo- sives to produce easily excavated muckpiles for the minimum possible cost. The art of blast design in the future will increasingly depend on an adequate understanding of the nature of the rock mass, the perfor- mance of explosives and the characteristics required of the muckpile to suit the chosen excavation machinery. Despite recent advances in blast simulation and the prediction of blasting performance, the best way to determine how a particular explosive will function relative to other explosives is to conduct properly designed and monitored field trials. This paper discusses recent work at Mount Thorley Colliery which demonstrates that field blasting trials can be monitored and analysed to provide quantitative data on the relative performance of bulk explosives. Techniques used in the trials included the sampling and analysis of explo- sives, insitu measurement of VOD, monitoring of near and far field vibra- tions, high speed and still photography and survey measurement of muckpiles. These techniques provided data for the analysis of throw, swell, fragmentation and burden movement together with data on the consistency and robustness of different explosive products. The blasting trials allowed both the shock and heave energy of various explosives to be observed in the field and led to the derivation of design rules for the use of differ- ent explosives at the mine.

Jan 1, 1988

By Peter Joralemon

I want to limit my remarks to epigenetic ore deposits, but do not necessarily subscribe to the classic theories of hydrothermal ore deposition. I will consider an epigenetic deposit as a primary deposit in which the economic minerals have been introduced subsequent to the formation of the enclosing rock, regardless of the source. Past ore discoveries have been made to a great extent by prospecting techniques that have remained relatively constant over the last many decades. In many cases the discoveries have been enlarged or enhanced with the use of technical tools such as geophysics, but theoretical geology, which should serve as a foundation for exploration, has shown little progress of practical importance since the turn of the century.

Jan 1, 1967

The fifth convention of the National Foreign Trade Council was held in Cincinnati, Apr. 18, 19 and 20. More than one thousand accepted delegates were registered, the American Institute of Mining Engineers being represented by W. L. Saunders and W. N. Thayer. The convention was called to order Thursday morning, Apr. 18, in the convention hall of the Hotel Gibson; by the Chairman, Mr. James .A. Farrel, president of the U. S. Steel Corporation, and was in continuous session for two clays, several group sessions being held simultaneously. The convention adjourned Saturday morning after receiving the report of the central committee. The dominant themes of the convention were: First, "Win the War" and second, "Establish Foreign Trade on a. Firmer Basis." The discussions included textiles, lumber, chemicals, automobiles, finance, and agriculture, and also those things in which mining engineers are particularly interested, metals, oil, and coal. The report of the central committee, which was adopted, recommended the stimulation' of production of all materials required for war purposes; the subordination of all trade that will not impose new and heavy penalties on our adversaries; the maintenance of such foreign trade as will support national credit and supply materials required for military and naval purposes; the continued interchange so far as possible of merchandise and products between the United States and. Latin-America, Asia and Oceania; the immediate increase of tonnage in the north Atlantic; the cheerful and whole-hearted cooperation of importers

Jan 6, 1918

By Bodnaras G. E, Sceresini P. A

The Filblast Cyanidation Process incorporates the advantages of intense high shear mixing, high dissolved oxygen concentration and high pressure to achieve extremely rapid gold dissolution rates. This is made possible by the unique design of the Filblast gas shear reactor. The reactor is a rugged and compact in-line device. The outer casing is protected by a polyurethane coating and the internal parts are of wear resistant polymer. The largest unit built to-date has overall dimensions of 1200 mm length by 300 mm diameter and has a capacity of 150 dry tonnes per hour at 40 - 45 per cent solids. Service life at this throughput is at least three months. The process may further be applied to high temperature leaching of refractory gold ores or other metals. Wear resistant metal or ceramic materials would be employed for this duty. Four mines are currently employing the Filblast Process for treating a variety of ore types ranging from highly reactive, almost impossible to treat, pyrrhotite/arsenopyrite to deeply weathered clay ore which forms a highly viscous pulp. The effect of shear thinning has resulted in improved adsorption kinetics resulting in higher carbon loading and reduced soluble gold loss. Total tonnage treated is approximately four million. Operating costs which include leasing and maintenance charges for the Filblast and pump power costs are about 16 cents per tonne. This is equivalent to about ten per cent of savings. Laboratory scale units having capacities up to 30 litres/min are available for test work but laboratory testing techniques so far developed do not accurately reflect the oxygen and cyanide savings which have been achieved in the plant.

Jan 1, 1994

The Filblast Cyanidation Process incorporating intense high shear mixing, high gas mass transfer efficiency and high oxygen concentrations under conditions of elevated pressure has now been been successfully applied in gold cyanidation mills since May 1993. The first commercial unit had a slurry capacity of 110 cubic metres per hour. Since then 230 and 450 cubic metre per hour units have been installed and a 1000 cubic metre per hour unit has been designed. Laboratory and pilot plant Filblasts have also been built.The reactor is a robust, compact in-line or end-of-line device and may be constructed out of a wide range of materials including wear and corrosion resistant alloys and ceramics. The Filblast Process may be applied to high temperature leaching of refractory gold ores and base metal concentrates.

Jan 1, 1997