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By M. J. Reasor, M. DiMatteo, J. M. Antonini, K. Van Dyke, Z. Ye

"The inhalation of silica has been shown to produce a dramatic inflammatory and toxic response within the lungs of humans and laboratory animals. A variety of cellular and biochemical parameters are used to assess the silica-induced lung injury. The purpose of this paper is to introduce the use of luminok:Jependent chemiluminescence as a new method to study inflammation in both phagocytic cells and lung tissue recovered from silicaexposed animals. Chemiluminescence, or the emission of light, accompanies the release of reactive forms of oxygen when phagocytic cells are challenged. In this study, male Fischer 344 rats were intratracheally instilled with either silica (10 mg/100 g bw) or saline vehicle. One day after the instillations. a marked increase in the chemiluminescence was observed in the lung tissue and bronchoalveolar lavage cells recovered from the silica- treated animals when compared with the saline controls. The light reaction was markedly decreased by either superoxide dismutase or N-nitro-Larginine methyl ester hydrochloride. Superoxide dismutase is involved in the enzymatic breakdown of superoxide anion. while N-nitro-L-arginine methyl ester hydrocholoride, a nitric oxide synthase inhibitor, prevents the formation of nitric oxide. When superoxide anion and nitric oxide react. they form the highly oxidizing substance peroxynitrite. This study then implicates peroxynitrite as an agent that may be responsible for some of the oxidant lung injury that is associated with silica exposure. The use of luminol-dependent chemiluminescence may prove valuable as a method to measure the earliest events in the inflammatory process. and may be an adjunct in studying the mechanisms that produce inflammation. - Environ Health Perspect 102(Suppl 10):37-42 (1994) IntroductionResearch on inflammation has not produced a method that links the initial events of the process to the controlling events. Rather, a variety of parameters are measured that are the result of and not the basis of the inflammatory reaction. Parameters such as tissue weight, edema, blood flow, enzyme and protein release, or production of metabolites (prostaglandins, leukotrienes) have been used extensively. A method is needed that could be applied to cells of a particular type, groups of cells of different types, and even tissue, in an attempt to study the kinetics of the inflammation as well as being sensitive enough to monitor the early events of the process . Since inflammation is so complicated, the relationship between the control of the initial events and the oxidation process has never been explained nor studied in any derail."

Dec 1, 1995

By Mao Chen, Baojun Zhao, Xiangfeng Cheng, Zhixiang Cui, Leonel Contreras, Anh Nguyen

Smelting is an important process in copper production to produce matte and slag.The slag,containing about 1–12% Cu can be further processed to recover the copper contaminated, but recycle of the slag concentrate reduces overall productivity and efficiency of the operation. The best solution is to minimize the copper loss to the slag. The entrained matte droplets in copper smelting slag may originate from a few sources. The present study aims to investigate possible copper matte loss mechanisms by visualization of room temperature experiments and high-temperature examination. It is believed that the gas bubbles from the matte phase disperse the matte droplets into the slag causing entrained matte in slag. Analyses of quenched slags from industrial operation and laboratory experiments confirmed that matte droplets in the slag are extensively associated with the gas bubbles. Water model is used to simulate the procedure and the bubble behaviors at the liquid-liquid interface are observed experimentally with a high-speed camera.

Mar 1, 2017

By Rey B. Marquez

This paper introduces and outlines the implementation of Reliability Centered Maintenance (RCM) at Phelps Dodge Hidalgo Inc. By using a disciplined approach to the everyday maintenance functions, a proactive strategy is being developed which "raises the bar" for plant maintenance. The main objectives are: integration of Operations and Maintenance partnerships, transformation of maintenance practices from a reactive to proactive mode through the introduction of a progressive Predictive/Preventive Maintenance program (PDM/PM) paradigm changes, increased management support of maintenance functions, introduction of new indices and root cause analysis, updated; training, and definition of RCM components. RCM is the vehicle being utilized to reach the higher level of equipment availability and utilization. However, the ultimate goal is to venture beyond RCM and into the new frontier of Total Maintenance Management (TMM).

Jan 1, 1998

By Robert J-M Ethier

"Sequential blasting has been introduced at Mines Gaspe to reduce the harmful effects associated with the instantaneously primed blasting method. Three stages of modifications had been tried to improve this method: trials of a rectangular pattern instead of the square one, trials of lengthened hole collars at the perimeter of the blast and trials of increased inter-row delay intervals from 35 to 50 ms. Results showed that improvements to the instantaneously primed blasting method were limited by the probability of increasing the number of bootlegs.Doing these modifications allowed the definition of a general approach to improvements before the sequential blasting method was introduced. This general approach included: planning of the mining sequence, following up on the drilling, loading and tying-in of each blast, compiling and evaluating blast results, comparing results from one bench to the other and moving along with one change at a time. This approach has permitted the successful introduction of the sequential blasting method in two steps: trials of blast by rows of delayed holes and trials of hole-by-hole blasts. The optimum result has been analyzed by high-speed camera and by computer blast simulations, The actual optimum sequential blast is obtained with a CORDLINE priming system using period 15, permitted in a large drilling pattern, with an intersequences delay interval of 230 ms and an inner-sequences delay interval of 50 ms.While these modifications were being introduced, a careful study of the drilling and blasting costs was made, which showed a sharp reduction of drilling cost per tonne. Even though there was an increased use of packaged slurry the blasting cost per tonne also dropped. The reduction in cost per tonne was explained by the fact that the average energy factor was maintained while the blasting pattern was expanded.The sequential blasting method, successfully introduced at Mines Gaspe, permits blasts of better quality, reduces the drilling requirements by more than 30% and helps to achieve improved productivity while minimizing costs."

Jan 1, 1984

By Neill T. J, Howarth D. F, Malcolm J. McPhersqn

For many years Isa Mine has seen the need for a continuous mining machine which will economically cut hard rock. Tunnel borers are unsuitable due to the size and inflexibility of the machine and the shape of excavation mined. The design of roadheader type machines will not permit the use of the necessary cutting technology. in 1983 a joint project was undertaken by The Robbins Company and Mount Isa Mines Limited to develop and to trial a machine suitable for cutting hard rock in an operating mine. The project was based on the proven technology of raiseboring applied to horizontal development. The Mobile Miner was fabricated and trialled in a disused quarry in the U.S.A. during early 1984. Following these trials, the machine was transported to Mount Isa and commenced mining in September that year. The initial duty was to continue the development of a decline commenced by conventional mining for a conveyor system to serve the deeper southern areas of the 1100 copper orebody. This system will permit direct tipping of copper ore to a new crusher complex and conveying of the - crushed ore approximately 2 kilometres to the central hoisting shaft facilities. The Robbins Mobile Miner MM120-3001 uses a vertical rotating cutting wheel mounted on a horizontal swinging boom to excavate a nominally rectangular shaped heading. The cuttings are collected on an apron and conveyed back through the machine. The resulting excavation is smooth-walled with no blasting damage to the surrounding rock. This provides a safer working environment than does conventional drill and blast development mining. Ground support requirements are considerably reduced.

Jan 1, 1986

By George W. Maynard

(Pittsburg Meeting, March, 1910.) AT the Pittsburg meeting of the Institute, May, 1879, I made the first announcement in America of the results obtained by Sidney Gilchrist Thomas and Percy C. Gilchrist, ill their efforts to eliminate phosphorus in the manufacture of steel in the Bessemer converter and the open-hearth furnace.1 The first published statement in an American newspaper was a reprint of the first Thomas-Gilchrist paper, 2 which I sent to J. C. Bayles, at that time the editor. At the suggestion of many friends who were present at the Pittsburg meeting, and others who are cognizant of the beginnings of the process in the United States, and for the information of the younger generation of the iron and steel fraternity, I have thought it eminently proper that the history of the process in detail should be given where I made the first announcement and where the process has had its largest development. During my residence in England, from April, 1873, to February, 1879, and as a member of the Iron and Steel Institute since 1874, I was present at many of its meetings during those years. At nearly -every meeting the burden of discussion was the question of the use of pig-iron containing phosphorus in the. manufacture of steel by the Bessemer or the open-hearth process. In my biographical notice of Thomas;3 read at the New York meeting of, the Institute, February, 1885, I show that the working-out of the process was not a hap-hazard or accidental inspiration, but the culmination of many years of investigation of experiments and theories which had been carried on and advanced by chemists and metallurgists at home and abroad. 1 Trans., viii., .5 (1879-80). 2 The Iron Age, vol. 22, No. 17, p. 3 (Oct. 24, 1878). 3 Trans.. xiii., 785 to 791.

Jul 1, 1910

By R. O. Burt

The Tanco pegmatite is located in the Bird River greenstone belt of south-eastern Manitoba approximately 160 km northeast of Winnipeg (Figure 1). The orebody was discovered in 1929 and subsequently attempts were made to exploit it for tin by Jack Nutt Mines Ltd. and later in the middle 1950's by Montgary Oil Ltd., who extensively developed but did not produce from its lithium deposits. In 1966 systematic investigation of the pegmatite as a potential source of tantalum led to the founding of Tantalum Mining Corporation of Canada Ltd. (TANCO), and production of tantalum concentrates from the Bernie Lake mine commenced in 1969. Tanco's currently jointly owned by Hudson Bay Mining and Smelting Co., Cabot Corporation, and the Province of Manitoba.

Jan 1, 1988

By U. Paakkinen, P. Eerola

In connection with theoretical studies of the dynamics and control of the flotation process, flotation cells and circuits at the Pyha- computer control of selective Cu - Zn - Fe sulfide flotation in the latter half of 1969. In this paper, the practical conclusions of these studies, conducted through simulation techniques, are summarized. The application of these results for control purposes implies a knowledge of the dependence of the flotation rate coefficients and the grade of concentrate on several factors, including aeration rate, froth depth, and reagent consumption. The relationships found in laboratory and plant scale tests are described. Off-line optimization studies, based on the relation- ships, are also described. The proposed steps in executing the computer control schedule are presented. In the first stage, a stabilizing control will be carried out using feed-back loops. A feed-forward control system which utilizes simple process models will also be tested. After these elementary stages, a proposed mathematical model of the circuit will be checked out and implemented with computer- run, plant-scale process tests. Off-line simulation will be continued in advance development of the control system. As a final step in the program optimal control of the process will be carried out through this model.

Jan 1, 1969

By Eyers G. C

Long Shaft was initially developed using a rail haulage system on every working level comprising battery electric locomotives and granby trucks loaded by rail mounted rocker shovels. Production was commenced using conventional hand held cut and fill mining methods. In an effort to improve productivity and reduce operating costs a mechanised cut and fill stoping method evolved to suit the wider sections of the orebody. To further improve productivity and reduce costs the mechanised levels of the mine are progressively being redeveloped to enable the use of trackless diesel haulage equipment. An added benefit of trackless haulage equipment will be the ability to place development mullock into stopes as Fill.

Jan 1, 1988

By Ray W. Ballmer

Historically, Bingham is a rail pit, starting with steam locomotives in 1906 and converting to electric locomotives in 1923. Ore production was maintained through an effective utilization of available rail equipment. From time to time as it became necessary to deepen the pit and as stripping ratios increased, various studies were made on alternate material haulage systems. Utilization of diesel locomotives, conveyor belts, and trucks have all been subjects of study, however, conversion from rail haulage utilizing electric locomotives could not be justified. Because of the gradual decline in ore grade, a program was approved in 1963 to raise ore production to 108,000 tons per day. This was designed to return copper production to the 1950 level. Attainment of this production level by expansion of the rail system had definite limitations and built-in inflexibility. Track and trolley wire relocation causes shovel down time in excess of that required for normal maintenance. Instability of the dumps and the resulting additional track maintenance increases greatly as the volume of waste material to be handled daily expands.

Jan 1, 1965

By A. K. Snelgrove

At a time when water resource planning is proceeding on a continental scale, such as the proposed $100 billion North American Water and Power Alliance, which would redistribute water among three nations, including seven provinces of Canada, 35 of the United States, and three States of Mexico, the selection of a single river basin for study may seem to require an apologia. None is offered because of ( 1) the magnitude of the Indus , itself a part of the great Indo-Gangetic Plain drainage system, with Himalayan sources, upon which the thickly populated northern sub-continent of Indo-Pakistan depends for agriculture and hydroelectic power; (2) the extraordinary problems created by dismemberment of the world?s largest irrigation system through legal beheading of the Eastern Waters under the Indus Waters Treaty of 1960; and (3) the herculean effort to contain the twin encroachments of waterlogging and salinization in a basin which faces a shortage of fresh water. The British irrigation system of barrages and canals on the Indus was a venture admirable in conception. Unfortunately, it is now a legacy burdened with unwanted consequences, due to interference with the hydrological regimen, particularly the rise of water table occasioned by leakage.

Jan 1, 1967

By E. R. Olson

The introduction gives not only a historical background but also touches on shaft sinking and surface construction and gives some general information on the Potash Conservation Regulations which the Saskatchewan government introduced in 1969. It also gives information on the corporate and local organization of Alwinsal Potash.

Jan 1, 1972

By D. J. M. Farnsworth

Since the 1.940's, the bulk of the ore production from the Sullivan Mine has come from pillars. These pillars, located from 100 to 2000 feet below surface, have been subjected to considerable ground pressure. Mining techniques were adopted to minimize the problems of deteriorating ground conditions. These techniques included an orderly sequential blasting of pillars along a retreat front, stage blasting of tall pillars in horizontal slices and utilization of broken pillars as "buffers". The latter two techniques involved leaving substantial tonnages of broken ore in place for as long as 4 years. Rapid oxidation of metal sulphides, with attendant heat and noxious gas generation, had occurred in a few very localized areas of the mine associated with a major water course. However, in a very short period starting in 1972, sulphide fires spread to several of the large blocks of broken ore that had been left inactive for lengthy periods. There proved to be no feasible method of extinguishing these fires, except by complete removal of the burning ore. The attendant problems of handling large tonnages of burning ore have had considerable negative impact on the mine operation. The chemical reactions involved in these sulphide fires have been studied by the mine staff to determine the conditions necessary for' initiation and propagation of the tires. Techniques to safely and efficiently handle hot ore have been implemented and refined. Lastly, and most important, mining methods at the Sullivan Mine have been revised to ensure that additional fires do not occur.

Jan 1, 1977

Dr David Dekker discussed the importance of a multidisciplinary approach to automation, the infrastructure required to support automation, and selecting the equipment for automation. Dekker stressed that automation involves a number of technologies. The mining industry is currently about part-way through the evolutionary process of achieving a fully integrated automation system. He pointed out that the final stages require parallel development of infrastructure such as mine communications. Technologies required for automation Automation systems consist of three parts: the gathering of information, the processing of that information, and taking action.

Jan 1, 1997

By Betty L. Gibbs

The ultimate objective of mine design is to determine the development and untilization of mining resources. Computer Aided Design (CAD) and automated mapping are becoming very popular in engineering and in mining. Any computer program which produces a design or model with the interaction of an engineer can be considered computer-aided design (CAD), but' the term CAD is often associated with interactive graphic design and mapping capabilities. Graphics can be effectively used to describe and model two-or-three dimensional mine workings, orebodies, and geologic structures. Interactive computer graphics is applied to mine design with a combination of deposit modeling techniques and the use of AutoCAD for interactive graphics and mapping. The combined system can perform a large part of the calculations and drafting work for geologic and mining design. Using computer calculation and graphics techniques, comparisons of alternatives, can be made quickly.

Jan 1, 1989

By Jack Craft

Local Environment Atmospheric conditions (or lack thereof) Drilling fluids are impractical Cuttings removal is a major concern Heat dissipation is a major concern Some tried-and-true mechanisms need air to function properly Gravity Low gravity means low downforce Microgravity means even less downforce Regolith Local dust may be highly abrasive Packaging for Spaceflight System mass is highly constrained The drill must fit within the spacecraft?s launch envelope Power is constrained

May 1, 2013

By James W. Babcock

Introduction Geologic ore deposit models are key to any exploration program. In the search for ore deposits, the geologist first tries to understand the genesis of known ore bodies. During reconnaissance and evaluation of a prospect, a valid exploration model of a known ore body can help the explorationist focus on critical geologic attributes of the target area. Exploration models can conserve exploration funds that might otherwise be spent collecting data not critical to delineating an ore body. This article examines the benefits of using models, factors to be considered in developing models, and examples of the way recent models have evolved. New exploration concepts and techniques are developed in response to increased competition in the mining industry. New techniques can give an exploration group a slight edge that may translate into a discovery. Mine geology staffs may find previously unlooked for extensions to the ore body by applying new genetic concepts. When all appropriate techniques are applied to exploration and mining efforts, greater efficiency and increased profits may result. Before the 1950s, scientists speculated on the genesis of ore deposits and other natural phenomena. But they presented their results as if universal and final, even though they applied to only a few deposits. Because it did not provide sufficient criteria to distinguish the genetic processes, the classic conflict between hydrothermalists, epitomized by Lindgren, and nonhydrothermalists did not help the minerals explorationist much. Important information about individual ore deposits, such as age of the host rocks and mineralization, composition of the mineralizing fluids, and separation of mineralizing and nonmineralizing events in the paragenetic sequence, could not be gathered with past equipment and methods. But these early concepts of ore genesis contained excellent empirical observations, perhaps the most useful parts of these hypotheses. Through the years, prospectors have found most of the ore deposits in the world using direct observations and their collective empirical wisdom - an empirical model. The geologist's contribution becomes increasingly important after the more obvious surficial ore deposits have been discovered. In Europe and North America that time has arrived. With the introduction of sophisticated equipment and matching techniques in the 1950s in geochronology, geochemistry, geophysics, remote sensing, and computers, many previously equivocal genetic questions can be resolved. This proliferation of highly technical data has allowed the construction of many well-founded genetic models.

Jan 12, 1984

By R. O. Burt, R. W. Bruce

"IntroductionGravity concentration, the separation of two or more minerals due to the difference in their relative specific gravity and usually in a fluid medium, is the oldest recorded form of mineral processing.The principles of gravity concentration were known to, and practiced by, the ancients and Hoover's commentary to De Re Meta/lied'' notes many early references.Over the centuries, as direct smelting ores became more and more uncommon, the mineral processing industry developed and along with it many varied methods of concentration. Gravity concentration declined rapidly in importance in the early twentieth century, and it is only in the last decade that its advantages are being re-evaluated.A significant proportion of ores are processed by gravity; a large proportion being in the iron and coal industries<'>, or in the treatment at very high volume of relatively coarse alluvial deposits. The tin dredges of South East Asia and Beach sand plants of Australia are prime examples.An indication of the broad application of gravity concentration is the variety of minerals presently recovered. A list is given in Table 1; this list is not exhaustive.Principle of Gravity ConcentrationGravity concentration methods separate minerals of different specific gravity by their relative movement in response to gravity and one or more other forces, the latter often being the resistance to motion offered by a viscous fluid, such as water or air.The relative movement of minerals to one another is achieved by a variety of methods. These are: separation in a fluid of intermediate density (heavy media separation); by stratification (such as in jigging); in a flowing fluid (cones, spirals, sluices etc.) and with a horizontal shear (shaking tables etc.)."

Jan 1, 1989

Are you afraid of the dark? Of course not, at least not since you were about six years old, anyway. But early man was - afraid of the dark, and he had good reason to be. Since he had no illumination other than fire and moonlight, he was at a disadvantage when it came to mixing it up with some of his fellow creatures. Sabre-toothed tigers, for example, could probably see quite well In the dark, and they were very real enemies. Sabre-toothed tigers haven&apos;t been seen in mining country for some time now; but it&apos;s st111 dark In a mine and, make no mistake about it, there are still enemies in the dark. The enemies are all the things that can injure you if they are not seen. Modern mines can be safe places to work for the trained miner who follows good work practices. But there are mining machines that make sabre- toothed tigers look like pussycats, and if you can&apos;t see well enough they can be ten times more dangerous.

Jan 1, 1976

INTRODUCTION The preceding chapters have brought us to a point in the mineral appraisal process where the composited sample values can now be used to estimate the grade and tonnage of the total mineral deposit. There are many techniques whereby drill hole composites and/or other sample data are used to assign grade and estimates to the surrounding rock. Matheron and his students have properly called such techniques extension functions. Before embarking upon a detailed discussion of extension functions, it is necessary that we take time to consider the concept of geostatistics as advocated by George Matheron who developed the "Theory of Regionalized Variables," which he published in 1962 (Matheron, 1971). The concept of regionalized variables has important application in the techniques of mineral appraisal. The position or location of a mineral sample within a deposit can be almost as important as its value. Geostatistics, when defined as "the application of the theory of regionalized variables* to the study of mineralized volumes of rock," takes into consideration the position as well as the magnitude of the value of the sample. The principles of geostatistics, as outlined by Matheron, represent a major step forward in the mineral evaluation process, because they provide a sound theoretical and practical basis for quantifying the geological concepts of (1) area of influence of a sample, (2) the continuity or lack of continuity of mineralization within the ore body, and (3) the lateral changes in mineralization according to the trend direction of an ore body and its orthogonal components; or in other words, a measure of the anisotropy of the deposit. Royle (1971) has defined the objects of geostatistic as being: "1. To estimate the most likely value of blocks of ore, or the values of the whole deposit; and 2. to estimate the errors of such estimates. This latter is important as, in addition to providing a check on unwarranted optimism, it shows where more valuation work may be needed." Because of the great importance of these concepts in mineral evaluation, an introduction into the theory of regionalized variables, and the study of a practical approach to its application is outlined here. REGIONALIZED VARIABLES VS. RANDOM VARIABLES Classical statistics, as discussed in earlier chapters, grew out of the study and application of probability theory. Probability is concerned with the outcome of random events and therefore classical statistics is built upon the theory of random variables, i.e., the probability of independent events. The validity of most statistical inferences depends upon sample randomness being assured for unbiased results. Where independent events cannot be assumed the results of statistical inference becomes suspect. On the other hand, geostatistics is concerned with variables that have position in space as well as magnitude, hence the term regionalized variables. Mineral deposits are not the only field to which the theory of regionalized variables is applicable. Many natural phenomena that demonstrate a relationship between change in magnitude and position in space are amenable to application of geostatistical techniques. Mineral deposits vary greatly in their geosta-

Jan 1, 1980