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By R. Carson Dalzell

The use of nuclear fission for chemical process heat offers the special advantage of high temperature, limited only by materials of construction. The process heat may be supplied economically at elevated pressures, since no compression of combustion air is required. For the initial effort in developing a high-temperature reactor, the indirect cycle, using helium as the heat-transfer medium, was chosen. The major problems are the design of high-temperature fuel elements, construction of an exchanger to transfer heat to process streams in the range of 2,500° F., and development of compressors capable of recycling helium at 1,000° F. and above. A conceptual design of a nuclear reactor to furnish process heat for coal gasification has been made. Spherical fuel elements utilizing a graphite structure, impregnated with uranium carbide fuel, were chosen, as spheres offer the possibility of easier loading and unloading of the reactor. Calculations of pressure drop and gas-pumping power for the system are included.

Jan 1, 1959

By Lloyd C. Venburg

Analytical and computer models are used to evaluate information obtained for the design and development of mine water control systems. Geologic, hydrologic, geophysical, biological, and chemical data must be gathered for use during all stages of mine development. Models allow the geohydrologist to use these data to predict the amount of ground-water inflow, the impact of dewatering and stream diversion on the hydrologic regime, equipment needs, and dewatering schedules. Stratigraphic and lithologic changes, faults, recharge and discharge areas, and aquifer parameters should be incorporated into the model to design and develop an effective mine water control system.

Jan 1, 1982

By Ricardo Oliveira Gallart de Menezes, Claudio Gerheim Porto, Reiner Neumann

This study presents the results of the mineralogical characterization of Ti-Zr ore from the Jiboia deposit, located in the municipality of Brejo Grande, Sergipe State, Brazil. The goal is to identify the main Ti, Zr, and REE carrier phases in the different particle size fractions in order to subsidize the development of a cost-effective processing route for the production of heavy minerals concentrate. The mineral resources are estimated at 31.5Mt @ 3.5% of total heavy minerals (THM) for the Jiboia Ti-Zr deposit, of which 5 Mt @ 3.39% THM were classified as measured and indicated. The mineralogy of the heavy mineral concentrate recalculated to 100% is represented by 22% pseudorutile, 20% ilmenite, 15% zircon, 5% rutile, 2% monazite, and 36% gangue. The ore minerals are preferably concentrated in the 150 × 53-μm granulometric fractions, which represents 80% of the THM and only 27% of the ROM (Run-of-Mine) ore. Therefore, by cutting the ore to 150 μm, it is possible to discard 73% of the ROM mass and recover 80% of the THM, including 100% of the zircon and monazite which are the most valuable minerals present in the heavy mineral concentrate. The global recovery of THM starts to decline rapidly in the fractions finer than 106 μm and the mass disposal (tailing) does not follow in the same proportion. Higher zircon contents in the concentrates of the fractions finer than 150 μm imply a significantly lower recovery of heavy minerals like ilmenite, pseudorutile, and rutile that make the fractions coarser than 150 μm.

Jan 9, 2024

By A. T. Yu

As a nation, we have been known as perhaps the most wasteful in history. From the perspective of engineers and builders on the other hand, planned obsolescence and demolition did beneficially pave way for growth and provided environment for new businesses. Recent economic recession and intense competition from overseas, however, have drastically changed the economics. The high cost of capital and the demise of indiscriminate plant expansion have totally altered the way we conduct our business and run our operations. As a response to increasing demands for better efficiency with little or no funding available, everyone is forced to make do and do better with whatever little he has. Today it nay not be an exaggeration to state that modification of existing facilities may have finally emerged as a way of life. This paper will outline examples of how several companies have effectively modified existing facilities to do more and do it efficiently without having to demolish everything and/or to spend a fortune.

Jan 1, 1985

By Janshi Sen

VERTICAL-INTENSITY magnetometers, such as the Hotchkiss Superdip and the Askania vertical field balance, are now [ ] widely used, because vertical-intensity charts give definite information for the location of upper pole, dip and strike, and approximate shape of the deposit. Again, a slow and steady increase of dip over a large area indicates a large deep-lying deposit, while a large dip limited to a small area and falling away rapidly suggests a small and shallow one. The complication comes more from the richness of the ore. A large body of lean ore near the surface might produce the same vertical-intensity chart as a rich ore at depth. This paper presents a method for calculating the maximum depth of a single-pole deposit and another for a two-pole mineral body, by utilizing data of both vertical and horizontal intensities as obtained by a Thalen-Tiberg magnetometer. As shown on the left side of Fig. 1, lean ore, rich ore and a single pole produce the same magnetic field. The depth of the pole, [ ] h, can be calculated from the following relation: [h=a=tan¢=G-F h=aXFy] where G is the vertical intensity at point A due to the pole; F, the horizontal intensity of the same; and a, the distance from the point of maximum vertical intensity or the vertical projection of the pole on the surface to the point of observation A. If an entirely covered deposit is indicated by magnetic measurements and boring cost estimated from the calculated depth is so reasonable as to encourage drilling, the ore should be struck somewhere within the limit of the calculated depth by the borehole. A number of such points as A should be taken for calculation, erratic results should be rejected and the average figure used for cost estimation.

Jan 1, 1944

By T E. Norgate

Salinity in Australia is caused by over irrigation and land clearing for agricultural use over the last 100 years. It is now the biggest threat to the quality of land and water in the Murray Darling Basin and Western Australia. Pumping the saline waters straight into the ocean or transporting the solid residue (mainly sodium chloride) to the ocean after evaporation of the water is expected to cost the taxpayer millions of dollars every year. This paper proposes that the salinity problem of Australia, at least in part, can be converted to an asset rather than a liability if it is exploited and used to make value-added products. The more value made out of saline waters, the more saline water is processed and therefore the more salt is extracted from the land. The value-added products that can be made out of saline waters are numerous and diverse. Rough calculations show that value addition to the saline waters could potentially generate up to $A 200 million per annum business in the Murray-Darling Basin. Although it is a challenge to make cost competitive products and find markets for these products it is possible that up to $A 100 million per year may be gained from import substitution. Value addition to salinity would also reduce the threat on the environment and existing agricultural industry. Investment to add value to salinity will create business in the region, nurture the local small population communities, and increase services and long-term employment.

Jan 1, 2002

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

The Federal Coal Mine Health and Safety Act of 1969 has dictated major changes in mine ventilation with regard to both air quantity and quality. Requirements have also been placed on the ventilation of beltlines, gob and face areas, and air velocities on trolley haulage roads are limited. Escapeways, separate from trolley haulage roads and on an intake split of air, must be maintained continuous to the surface. These and other similar requirements have not only precipitated several modifications to existing ventilation systems but also have greatly increased the complexities of new mine ventilation planning. It is apparent that the use of computers in ventilation system analysis and design is a necessity. SUMMARY Although computer oriented analysis of mine ventilation systems was introduced over two decades ago, it has yet to receive widespread acceptance in the United States. Central to this problem is the fact that, while many computer programs for network analysis have been developed, no attention has been paid to the development of computer input data. Consequently, without this foundation, program applications have been infrequent. This thesis has directly attacked this problem and has presented all pertinent information basic to the development of good computer input data. The areas that were covered include quantity measurement, pressure measurement, fan testing, survey data balancing, and the development of a network schematic from the ventilation survey results. These discussions on data collection and the corresponding reduction to computer coding have been illustrated by an application of a ventilation simulation program to an existing mine in Southwestern Pennsylvania. The use of a ventilation

Jan 1, 1977

By John Brouwer

Through the use of good preventive maintenance procedures in which the work of both production and maintenance personnel is well-coordinated, production downtime can be drastically minimized, and costly repairs and interruptions in planned maintenance and production schedules can be eliminated. There had been some conflict in the past between production and maintenance people over the proper method of achieving maximum machine performance. The usual practice was to operate production equipment at maximum capacity for the longest possible time until breakdown occurred, and then make hurried repairs to get back into production. In most cases, these repairs involved unscheduled work and were thus performed inefficiently. Both production and maintenance have the same objective: to produce a quality product at maximum efficiency and at minimum cost. Preventive maintenance is a common tool available for both production and maintenance personnel to achieve this objective. Actually, one of the main objectives of preventive maintenance is to find any abnormal machine condition that may cause machine failure before a breakdown occurs. This makes it possible to plan and schedule maintenance work with the least amount of interruption and plan production volume with a higher rate of accuracy. Maintenance people prefer to perform this work on a scheduled basis and get away from the "crash" situation that accompanies breakdowns. They thereby increase the utilization of available manpower and machine time, prolong equipment life, and improve maintenance costs.

Jan 1, 1979

By J. S. Roper

"IntroductionSNOW LAKE is situated in northern Manitoba at latitude 54° 55 and longitude 100°, 400 miles northwesterly of Winnipeg, 80 miles northeast of The Pas, 80 miles east of Flin Flon. A 38-mile road from Wekusko, on the Hudson's Bay railway, serves the community.The mine is located in and close to the southern edge of the Precambrian Shield in typical low-relief muskeg and lake country.The Howe Sound Exploration Company, Limited optioned the property from Nor Acme Gold Mines, Limited, after preliminary diamond drilling had outlined two orebodies of low-grade arsenical gold ore.Following the examination and study of geological data and of 50,000 feet of diamond-drill core, and metallurgical tests made during 1942 to 1945, a decision was made to develop the mine and build a 2 ,000-ton mill concurrently. This development has been described by G. C. Lipsey in a paper entitled The Development of a Mining Operation from Diamond-Drill Data which was published in the August. 1952, issue of Mining Engineering.Geological Features of the OrebodiesThe orebodies at Snow Lake occur in volcanic rocks of acid to basic composition and, to a lesser extent, in intrusive hornblendite. The hornblendite is a massive, uniform, .coarse-textured rock except in the immediate vicinity of the ore zone, where it becomes sheared and carbonatized. The acid volcanics have been converted to quartz-garnet-biotite gneiss, and the basic volcanics to amphibolite gneiss. Orebodies have been formed by the replacement of all three rock types."

Jan 1, 1955

By J. M. Gaines, C. H. Herty

IRon oxide (FeO) plays an extremely important part in the manufacture of steel. In the open-hearth furnace and the Bessemer converter it is the chemically predominant compound and controls to a large extent both the operation of the furnaces and the composition and quality of their products. Almost all of the refining action is carried out through the medium of FeO, which oxidizes carbon, manganese, silicon and phosphorus. At the end of any open-hearth or Bessemer heat the steel contains dissolved iron oxide, which must be wholly or partly eliminated. The type of deoxidation product depends on the amount of dissolved iron oxide and on the deoxidizer used. After the heat has been deoxidized and while it is being teemed, iron oxide diffuses from the ladle slag into the metal, causing losses of deoxidizer and increase in iron oxide content of the steel. It is generally believed that non-metallic inclusions are responsible for a great many failures of steel in service and for decreased yield of steel during rolling. The basis of most non-metallic inclusions is dissolved iron oxide. This investigation was undertaken in order to determine the amount of iron oxide that will dissolve in iron under various conditions. Steel-making slags are complex and it has been thought best to determine solubility under simple slags as a first step. The study is being continued under slags whose compositions approach those of operating slags Previous Investigations The solubility of oxygen in iron has been determined by a number of investigators (see Table 1) but their effort's have been directed toward the

By Samanta Neves da Silva

Depósitos estratiformes são característicos por apresentarem irregularidades nos contatos entre minério e estéril, motivo que requer especial atenção no planejamento de lavra. No depósito de Bauxita em estudo, a definição da geometria da camada de minério é realizada por interpretação dos furos de sondagens com espaçamento médio de 200 metros. O modelo gerado dos contatos litológicos, comumente, não incorpora as oscilações em curtas distâncias das elevações (Z) entre furos, o que influencia na fase de modelamento geológico, logo, na previsão dos fatores de diluição e perdas de minério. Este trabalho propõe agregar dados de curta distância, aumentando as informações entre furos de sondagens e, a partir das medidas de cota no topo e base da camada de minério, melhor refletir a geometria do corpo de minério. Assim a metodologia se divide em: criar modelos de superfícies interpoladas irregulares de topo (SIT) e base (SIB), considerando as informações de curta distância; analisar elevações médias em cada superfície, a fim de pressupor superfícies planas de lavra no topo (SPT) e na base (SPB); verificar a amplitude entre essas superfícies - SITxSPT e SIBxSPB, mensurando os fatores de perdas e diluições de minério a partir da diferença entre as elevações. O produto final deste trabalho consistiu da quantificação dos fatores de diluição e perdas de minério, aplicadas ao planejamento de lavra de curto prazo, otimizando o aproveitamento dos recursos e, consequentemente, aumentando a vida útil da mina.

Aug 8, 2018

By Salvatore Fancello, Ferruccio Cribari, Amerigo Tanzi, Mauro D’Angelo, Massimo Lodico, Alessandro Bertero, Eliano Romani, Tommaso Gondolini, Fabio Giannelli

"The new metro line “C” entails the construction and rehabilitation of 24 stations and 21,5 km of metro line, 13 of which carried out underground; the new metro line will improve the transportation system of a congested city such as Rome.The new line “C” of San Giovanni metro station will be constructed adjacent to the existing line “A” of San Giovanni station; the new metro line “C” is deeper than line “A” and will underpass the existing station. The underpass project envisages an Artificial Ground Freezing in order to excavate two new tunnels, while keeping trains running in the safest possible condition.In order to allow trains to regularly run to and from the existing station’s line “A”, a temporary structure for rail support, during excavation of the under-crossing tunnels, was installed and a real-time monitoring system was devised in order to control both soil temperature during freezing activities and the existing station’s behavior. The monitoring system has been one of the key to the success of the project.The excavation of tunnels under the water table, with a hydraulic head of over 10 m in not homogeneous soils having different mechanical properties and permeability and below existing sensitive structures, involves special ground freezing sequences and methods, as well as peculiar drilling systems and operations, such as TDDT (Trevi Directional Drilling Technology).THE NEW “C” LINE OF ROME’S METROThe world’s most complex and extraordinary Metro System is currently being built in the heart of Rome. Its underground route stretches underneath the most important monuments, churches and historical buildings.Rome’s Metro Line C is the longest urban underground railway in Italy and it is the first line in Rome to extend further east to the Great Ring Road, thus bridging the gap between the farthest suburbs and the Historical Centre. It is an original project, carried out mostly underground at a depth of 25/30 metres below road level."

Jan 1, 2016

By Mutmansky J. M, Organiscak J, Qin J, Bhaskar R

The results of a two-year research study into the relationship between quartz dust levels in host material and in respirable dust in continuous mining sections are presented in this paper. The experimental design and sampling procedures for underground data collection are outlined. The sample analysis procedures for quartz determination, the analysis results and conclusions of the study are discussed.

Jan 1, 1988

By William H. Engelleitner

Agglomeration by balling in cylindrical or shallow pan devices dates back to the early part of this century. The first sintering tests conducted by Dwight-Lloyd on nonferrous ores included a mixing step for ore, flux and fuel carried out in a deep pan device similar to the balling pans, or discs, presently in use. Further work directed mainly toward sintering of ferrous and nonferrous ores always included a preparatory step, usually referred to as mixing, agglomerating or green-balling of the ingredients. In the late forties and early fifties two methods of particle preparation prior to firing were in general use. In Europe the balling pan was used predominantly, both as a mixer and as a pelletizer. In the United States many pilot plants and semi¬commercial plants used balling drums. When the first iron ore pelletizing plants were built in this country, the most frequently used device for green-balling was the cylindrical drum. At the same time, the pan device was used both in Europe and the United States for many other materials such as fertilizer, cement, flyash, alumina and copper concentrates, as well as to mix the feed for sinter machines. The difference between these two balling devices - -the drum and the disc - has been the subject of much discussion and is well covered by several papers included in the 1962 publication "Agglomeration' issued by AIMS, based on their 1961 International Symposium held in Philadelphia. (1)

Jan 1, 1965

By S. Mathur

Oxide particles are commonly used as fillers in plastics, paper, rubber etc. (particulate composites). The successful fabrication of such composites is dependent upon the adhesive strength of the filler particles to the matrix. The compatibility of the matrix and the filler particles is generally enhanced by adsorption of surface modifiers such as surfactants and polymers at the particle-matrix interface. In order to develop a scientific basis for selection of appropriate modifiers it is necessary to understand their adsorption mechanism(s). Specifically, adsorption of polymeric additives is attributed to a combination of chemical and electrostatic interactions, hydrogen bonding and van der Waals forces. Hydrogen bonding has been suggested to be the primary adsorption mechanism for non-ionic polymers. However, a literature survey of Poly(ethylene oxide)(PEO)-oxide system suggested PEO, a non-ionic polymer, to be substrate specific. A systematic study was undertaken to investigate the adsorption mechanism(s) of a PEO on oxide particles. It was determined that strong Bronsted acid sites on the surface interact with the ether oxygen, a Lewis base, of PEO to induce adsorption. In this work characterization of PEO binding sites on oxides is reported and the mechanism(s) of PEO adsorption discussed.

Jan 1, 1997

Facies associations in the Okiduse Volcanics, woodlark island, suggest that two major volcanic centres erupted synchronously during the Middle Miocene. These centres are referred to as the Watou Mountain Eruptive Centre and the Uvarakoi Caldera. The Watou Mountain Eruptive Centre, centred on Boganuse Mountain in the Okiduse Range, was a typical, moderate-sized composite volcano (or stratovolcano). The seq-uence is readily divisible into lava (Boganuse lava unit), breccia (Nikuben breccia unit) and epiclastic (Talpas sandstone unit) dominant facies, typical of composite volcanoes. These facies girdle Boganuse Mountain and they are interpreted to represent vent, cone forming and ring plain associat-ions, respectively. These facies indicate a reconstructed volcano of approximately 1,700m height with a basal diameter of 7km. The presence of limited exposures of intrusive associated with the vent facies (Kuike'beimmicrodiorite) suggests that the volcano is only partially dissected. The Uvarakoi Caldera is a felsic volcanic system contrasting with the mafic Watou Mountain centre.

Jan 1, 1994

By JAMES E. TILSLEY

Veins at St. Lawrence near the tip of the Burin Peninsula in southeast New/ oundland have been the major Canadian source of fluorspar. Some 2.8 million tonnes were shipped during the period 1933-1977, mostly from five of the more than forty veir.s known. Most of the veins occur in granite. individual veins may be several km in length, comprising a number of mineable lenses up to 760 m long and 25 111 thick. Fluorite content averages about 50 per cent, but may exceed 90 per cent locally. Quartz, calcite, barite and a few sulphides are the other vein constituents. Jn recent years, gravity concentrates were shipped to a flotation plant at Arvida, Quebec, where the fluorspar concentrate was used as a flux in the making of alum in um. Competition f rom Mexican fluorspar was a major factor in the closure of the mines. Ample reserves are available should economic conditions improve.

Jan 1, 1984

By S. J. Pearce

"INTRODUCTION AND SUMMARYComplaints have been made regarding dust respirators that may be used in coal-mining operations. Some of these complaints may be due to improper use of the respirator, inadequate knowledge of its purpose and mode of functioning, poor choice, poor fitting, or inadequate maintenance. It is hoped that this circular will answer these complaints by discussing the various factors relating to the proper use of dust respirators in general and in coal mines in particular.It is pointed out that dust respirators are not to be used as a substitute for dust-control measures. The construction, functioning, choice, fitting, and maintenance of dust respirators are discussed.FIELD OF USEThe function of the dust respirator is to prevent the wearer from inhaling harmful quantities of dust by removing dust from the air he inhales.A dust respirator is not to be used as a permanent substitute for dust-control measures. It is to be used as a temporary substitute until dust-control measures can be instituted or as a protective means where dust-control measures are impracticable, as in applying rock dust in bituminous-coal mines.The following sections of the ""Federal Mine Safety Code for Bituminous-Coal and Lignite Mines in the United States"" 2/ emphasize the fact that every effort should be made to keep the amount of dust in the air of the working places as small as possible:"

Mar 1, 1950

By Douglas J. Harvey, Chi-Mou Ni

"This paper presents an analysis technique for the solidification of metal castings. This method, based on a modified finite difference scheme with an irregular mesh, is capable of dealing with the complex geometries of castings. The nonlinearities in material properties of specific heat and thermal conductivity, arising from the phase change during solidification, are accounted for in the step-by-step calculations. Two solidification problems are solved with this analysis technique and the calculated results compare satisfactorily with experimental data. IntroductionCasting process design engineers are often faced with the difficult problem of designing castings to be produced porosity-free. Since the solidification of metal is affected by many interacting variables such as the thermal conductivity, density, and specific heat of both the molten metal and the mold, it is easily seen why this is a difficult task.Typically, casting tooling design is an intuitive process which builds on past successful methods. After processing equipment is constructed, trial castings are made and examined for dimensions and integrity. Changes in the tooling are generally required to improve casting soundness or to reduce cycle time. In the permanent mold process, tooling is complex and difficult to alter after initial construction. The water-cooled steel molds are part of the complete automated system. Associated holding furnaces, pouring ladles, casting conveyers, and utility connections all make other than minor adjustments a costly and time consuming task. An analytical method for using the principles of heat transfer for predicting solidification patterns would be of great value in the permanent mold process by minimizing costly changes."

Jan 1, 1986

By L. H. Harrison

In coal mines equipped with electrically driven mechanical mining equipment, the problem of protection for electrical circuits and machinery important, because the hazards of fires and explosions resulting from electrical failures is greater than in most other industries. There is need for better methods and improved protective devices for this service. Studies and tests designed to determine possible value of the short-circuiting contactor as an electrical device for coal mine service were investigated. Preliminary made to determine the operating characteristics of the device, after which tests were made under actual service in three coal mines. Ordinarily, electrical protection in coal mines is divided into three classes, as follows: 1. Overload protection that is intended to protect against damage from overheating and excessive mechanical strain due to overloading. 2. Short-circuit protection that provides a means of de-energizing the equipment instantly when an accidental short circuit occurs in the equipment or on the power system. Short cm protection tends to damage from fires and, explosions resulting in the dissipation of large amounts of electrical energy in a short circuit. 3. Ground fault protection that, in its various forms, is intended, to maintain the frames of electrical equipment at or near the same potential surfaces in contact with the earth for the purpose of safe-guarding human life.

Jan 1, 1951