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By James M. Reichman

Waterjet assist of mechanical cutters has been demonstrated in a variety of laboratory studies as well as on field equipment. As this technique becomes more widely accepted, it will be necessary to develop methods of minimizing the horsepower and water requirements. In machines such as roadheaders, continuous miners, and longwall shearers, the use of waterjet assist can be optimized through the development of phasing valves. Phasing valves will allow only the cutters in contact with the rock to be assisted. Since only 30 - 40% of the cutters are in contact with the rock, the saving power is significant. Flow Industries has developed a phasing system for use on roadheading machines. This system allows the operator extensive control of the angle of assist as well as the quadrant being assisted. This system could be greatly simplified for production machines and adapted for use in continuous miners and longwall machines.

Jan 1, 1985

By Vincent A. Scovazzo

Benchmarking is a business management process that seeks improvement through the study and reapplication of practices conducted by industry leaders. This discussion presents objectives and organization of benchmarking applied to mining geomechanics. Similar procedures have been successfully applied to mining companies, laboratories, and research organizations involved in mining geomechanics throughout the world. Benchmarking is a structured process that allows an organization to learn from the "best" in the field. The objectives of benchmarking vary depending on the company's targeted areas for improvements. Typical goals include ground control cost reduction, enhanced safety, optimization of geotechnical staffing, development of state-of-the-art design procedures, or the adoption of the "best in the field" geotechnical data management. Once the objective of the study is established and the practices and procedures to be benchmarked are identified, a benchmarking team is formed from internal and outside specialists. Benchmarking in geomechanics is fundamentally different than in most other fields because of the effects of local geologic conditions and regulations, both of which must be understood by all on the benchmarking team, before a comparative analysis can be made.

Jan 1, 2000

By William C. Geitz, Dan Fitzgibbon

Lightning has always posed a serious threat to blasting operations, especially within the mining and construction industries. In recent years, technological advancements in communications systems and microprocessors have significantly improved the accuracy and efficiency of lightning detection and warning instrumentation. These advancements have increased the availability of highly reliable, accurate and affordable systems for use within the explosives arena.

Jan 1, 1991

Jan 1, 1915

By R. G. Hamm

A brief outline covering the shovels and draglines in use in the open-pit mines of Western Canada, including British Columbia, Alberta and the Yukon, is given, followed by the procedure for the selection of the correct wire rope for each application. Such fa ctors as wire rope constructions, lay directions and types of cores are mentioned. Once the correct wire rope has been selected, there are variousfactors that can affect the service fife ofthe rope and the reduction ofdown-time during rope change-overs. Factors such as hairpin winding, types of Becket loops, and shovel drum and bail adaptors are described.

Jan 1, 1979

By Charlie Wyche

Principal mineral products in the Dominion of Fiji were gold, silver, pit and quarry construction materials, and cement. In 1981, the combined value of these commodities accounted for about $11.6 million,2 over 85% of the total value of mineral output. Production of cement, sand and gravel, and quarry products increased substantially above the 1980 level. Mining bated on gold production was decreasing, and employment in the industry was declining. The better grade deposits in the one active mine were worked out, and only another 10 years' production at current rates was estimated to remain. While the high world gold price of 1979-80 led to intensive exploration, there has been little sum.

Jan 1, 1983

By Harry Perry

One of the most notable achievements of the iron and steel industry in the United States in this century has been the general increase in productivity of individual blast furnaces and the reduction in coke rate. Most of the improvement in furnace operations has occurred within the past decade. During this time the output of the average furnace increased about one-third, while fuel rates decreased from 15 to 20 percent. For example, in 1949, the iron and steel industry produced 811.2 short tons of pig iron per blast-furnace day with a coke rate of 1,870.4 pounds per ton of pig iron, By 1960, the average production of pig iron per blast-furnace day had risen to 1,182.4 tons, while the coke rate had decreased to 1,497 pounds per ton of pig iron. These figures are averages for the entire industry; many furnaces produced over 2,000 tons per day and one furnace, operating on pellets, reached 2,700 tons of pig iron per day, Coke rates of individual furnaces varied, but some furnaces operated on less than 1,200 pounds per ton of pig iron. The significance of this decrease in coke rate is shown clearly when data on pig-iron production and coke consumption in 1959 are compared with 1948. In 1948, 57.3 million short tons of coke was charged into blast furnaces to produce 60.1 million tons of pig iron; in 1959 only 47.6 million tons of coke was needed to produce 60.2 million tons of pig iron. Thus, in 1959, nearly 10 million tons less coke was required to produce about the same amount of pig iron as was produced in 1948.

Jan 1, 1962

By Paley N, Cameron A, Townson P

Although blasthole deviation is a problem which can seriously affect blasting operations, there is little practical emphasis on controlling this deviation and no practical emphasis on understanding its practical behaviour. The most common way of dealing with it involves tight control over drill set up and surveying hole paths. The surveying might involve simple collar location and inclination measurement to estimate the hole's actual path. At best, some operations routinely survey hole paths after all holes in a stope have been drilled. In addition, although there is an expectation that holes will deviate, there is no planning for this behaviour in order to reduce its impact on the blast. Design decisions are invariably made with the assumption that holes are straight. If and when surveys reveal problems it is possible only to adjust charging and initiation to 'work around them'. In extreme cases the drill might be recalled to fill in gaps. The lack of planning and the lack of understanding are doubtlessly linked.A model is presented that will predict the expected path of a drill hole. By knowing how a selected few holes deviated it is possible to make a good estimate of the deviation of other holes in the same rock mass. After minimal calibration the model can be used to increase the amount of information for a given amount of surveying or the amount of surveying can be reduced while maintaining the same level of knowledge of blasthole deviation. Equally important is the ability to plan for the deviation in future drilling through altering the initial collar angles or drilling from different locations. It is the authors' hope that planning for hole deviation becomes as much a part of the design process as planning for detonator delay scatter and explosive performance variation.

Jan 1, 1992

By Larry M. Southwick

Extraction of gold and other metals from ores suspended in liquid slurries often involves gases (such as oxygen) as a participant in the reaction. An important factor then in setting the rate of extraction can be mass transfer of the gas into the liquid and/or solids. A number of recent studies have indicated that as solids loadings increase, mass transfer rates of gas into solid-liquid mixtures decreases. This would seem to imply that lower solids loadings would be beneficial to increased reaction rates. However, since it is the solids which are being reacted, a most intriguing paradox is created. More solids should lead to more surface area to react, but it seemingly also provides less gas to react. So is the reaction faster or slower as solids loadings increases? The creation of this paradox is imbedded in how mass transfer and reaction data is collected and measured, how it is analyzed and correlated, and finally on the rate controlling steps in the reaction. An alternative analysis of these studies is presented which clarifies and eliminates the paradox. The analysis applies to water slurries as used in gold or other metal leaching processes or in bio-hydrometallurgy, as well as to molten metal/solid/gas mixtures such as might be encountered in submerged gas injection.

Jan 1, 1999

The Navajo Nation is the largest Indian tribe in the United States and occupies a reservation encompassing about 16 million acres in northeastern Arizona, southeastern Utah, and northwestern New Mexico, with three satellite reservations in western and west-central New Mexico. Coal mining is conducted on a commercial scale at four large surface mines: two are in northeastern Arizona and the other two are in western and northwestern New Mexico. The principal coal-bearing region in Arizona is the Black Mesa coal field, which underlies about 3,200 square miles in the northeastern part of the state. The Black Mesa coal field lies within the boundaries of the Navajo and Hopi Indian Reservations and makes a significant contribution to the economies of both tribes. Coal reserves in this field are estimated to be 352 million tons, less than one-tenth of one percent of U.S. coal reserves. This coal was first mined by prehistoric Indians as fuel for cooking and heating. It has been estimated that the Indians removed more than 100,000 tons between 1300 and 1600 A.D. The coal-bearing region of the Navajo Reservation in New Mexico is located in the San Juan Basin. The Navajo Mine, which supplies coal for the Four Comers Power Plant, is located in this area. The Office of Surface Mining's Albuquerque, New Mexico, Field Office is responsible for regulating mining and reclamation on Navajo land. The Navajo Abandoned Mine Land Program was approved May 16,1988.

Jan 1, 1992

By E. T. Turkdogan, J. H. Swisher

bi the fivst part of the paper results ave given on the rate of decarburization of Fe-C melts ln CO2-CO atmospheres at 1580°C. The rate -controlling step is believed to he that irvlloluing dissociation of curbotz dioxide on the suvfuce of the melt. 4 genevral reaction mechanistm is poslnlated jor gels-t11eta1 veactions oc-curit~g on the surface of iron coutcotamncited with chemi-sovbed osygesL. Oxygen the present work on decavbuvization of liquid iron and previous studies on the kinetics of nitrogen absorption and desorplion are discussed in terms of the postulated mechanism, ManY of the early studies of rate of decarburization of liquid steel were of an exploratory nature and laboratory exppriments carried out pertained to open-hearth or oxygen steelmaking processes. References to previous work on this subject may be found in a literature survey made by Ward. Using more sophisticated experimental techniques, several investigators have recently studied the kinetics of decarburization of molten Fe-C alloys in oxygen-bearing gases. For example, Baker et al2.' reported their findings on the rate of decarburization of liquid iron, levitated by an electromagnetic field, in carbon dioxide-carbon monoxide-helium atmospheres. In these levitation experiments the samples used were small in size, e.g., -0.6-cm-diam spheres weighing -0.7 g, and the rates were measured for decarburization from about 5 to 1 pct C at 1660°C. The rates obtained under their experimental conditions were considered to be controlled primarily by gaseous diffusion through the boundary layer at the surface of the levitated melt. Parlee and coworkers3 measured the rate of absorption of carbon monoxide in liquid iron. The rates were found to follow first-order reaction kinetics, yielding a reaction velocity or a mass transfer coefficient in the range 0.2 to 0.4 cm per min. The coefficient was found to decrease with increasing carbon content of the melt. These investigators attributed the observed rates to the transfer of carbon or oxygen through the diffusion boundary layer adjacent to the surface of the melt. In the work to be reported in this paper, an attempt has been made to study the kinetics of gas-metal surface reactions involved in the decarburization of liquid iron. EXPERIMENTAL The experiments consisted of melting 80-g samples from an Fe-1 pct C master alloy in an induction furnace and decarburizing in controlled CO2-CO mixtures at 1 atm pressure and 1580°C. The master alloy was prepared by adding graphite to electrolytic "Plastiron" melted in racuo. None of the impurities in the master alloy exceeded 0.005 pct. The reacting gases were dried by passage through columns of anhydrone; in addition, CO2 impurity in carbon monoxide was removed by passage through a column of ascarite. A schematic diagram of the apparatus is shown in Fig. 1. A 1.25-in.-diam recrys-tallized alumina crucible containing the sample was placed inside a 3-in.-diam quartz reaction tube, all of which was surrounded by an induction coil. A 450-kcps induction generator was used as the power source. Water-cooled brass flanges, which contained the gas inlet, gas exit, and sight port, were sealed to the top of the reaction tube with epoxy resin. The reacting gases were metered with capillary flowmeters and passed through a platinum wire-wound alumina preheating tube, 0.25 in. ID and 11 in. long. The gases were preheated to about 1300°C. A disappearing-filament optical pyrometer was used to measure the melt temperature. The pyrometer was initially calibrated against a Pt-6 pct Rh/Pt-30 pct Rh thermocouple. The temperature was controlled to within +10°C by manually adjusting the power input to the induction coil. In a typical experiment, an 80-g sample of the master alloy was melted in a CO2-CO atmosphere having pcO2/pco = 0.02 and flowing at 1 liter per min. A negligible amount of carbon was lost and no significant reduction of alumina from the crucible occurred during melting, e.g., 0.005 pct Al in the metal. After reaching the experimental temperature of 1580°C, the gas composition was changed to that desired for a particular series of decarburization experiments. The duration of the transient period for obtaining the desired gas composition at the surface of the melt was about 20 sec . The flow rate of the reacting gas was maintained at 1 liter per min. After a predetermined reaction time, the power to the furnace was turned off. During freezing, which took about 10 sec, the amount of gas evolution was not sufficient to result in a significant loss of carbon. The samples were analyzed for carbon by combustion and in a few cases they were analyzed for oxygen by the vacuum-fusion method. RESULTS A marked increase in the rate of decarburization of iron with increasing pcO2/pco ratio in the gas stream is demonstrated by the experimental results given in Figs. 2 and 3 for pco2/pco ratios from 0.033 to 4.0. In one series of experiments, denoted by filled triangles in Fig. 2, the reacting gas was diluted with argon (48 vol pct) resulting in a slower rate of decarburization. Samples from two series of experiments with pco2/pco = 0.033 and pco2/pco = 0.10 (with argon dilufion) were analyzed for oxygen. In these Samples the oxygen content increased with reaction time

Jan 1, 1968

By G. Pan

A geostatistical approach is proposed for the design of infill drilling programs. The method consists of the following four major steps: developing geological favorability models, delineating mineralization and ore envelopes, classifying resource potentials, and designing infill drilling patterns. Geological modeling develops the permissible geological zones in which infill drilling is designed. Modeling mineralization and ore envelopes establishes criteria on the potential blocks to be drilled. The blocks that are included within the ore envelopes are considered in the infill drilling. The following four types of resource potentials are used in this analysis: measured, indicated, possible and barren. Blocks in the indicated category are the top targets to be confirmed in infill drilling. Blocks of possible resources may be considered exploration targets. The algorithms involved in the analysis include indicator favorability analysis, indicator kriging and ordinary kriging. A case study on a gold deposit of the Carlin type is presented to demonstrate the methodology. The deposit was originally delineated by a sparse drilling program with about 230ft of average spacing. The infill drilling design, based on the new method, suggests a significant reduction on the number of holes from a regular-grid infill drilling pattern.

Jan 1, 1996

By Frans van Grunsven, Cees van Rhee, Geert Keetels

One of the obstacles during the initial phases of project development is the assessment of the environmental impact. Mining residue, consisting of fine seafloor sediments, are to be discharged subsea to mitigate the impact of these suspended particles. In order to test the effectiveness of discharging in proximity of the seabed, a numerical model is developed within the open source software package OpenFoam. Dedicated laboratory experiments for numerical model validation are discussed within this paper. INTRODUCTION Siltation is considered one of the major pressures on the environment for a seabed mining operation. Siltation is defined as the pollution of water by a high concentration of suspended sediments like clay or silt. This can be caused by two main activities during the mining process: the spill loss during the excavation and the return flow of undesired seafloor sediment after ore filtration on the ship. In a concentrated cloud, these fine particles form a so-called turbidity plume. Prediction of the size of these plumes and the created layer thickness of deposited sediment is a crucial part of the environmental impact assessment. The challenge in predicting the behaviour of these plumes is found in the wide range of scales involved in the process. At the point of origin, the turbidity plumes spread mainly under the influence of turbulent whirls created by an initial momentum and a buoyancy difference due to the presence of the suspended sediment particles. If carried by ambientcurrents, these plumes can spread for several kilometres before blending in the background.

Jan 1, 2018

By L. Kaufman

A range of processing conditions and compositions have been evaluated in order to optimize the properties of TiB2-(Ni,Cu) composites for application as a non-sparking tool material for use in coal mining operations. Fifty billets containing from 70 to 9S weight percent titanium diboride were hot pressed at 3000 psi between 2400°F and 2650°F. Samples which were cut from these billets were used to measure hardness, bend strength and impact strength so that composition/processing optimization could be effected. Eight compositions selected on this basis were evaluated by incendivity tests in order to choose the best composition. The best results were obtained for an 85 w/o TiB2-12 w/o Cu-3 w/o Ni composite hot pressed at 2650°F and 3000 psi. This material appears to be the best choice for fabrication of coal cutter bits to be evaluated in field tests.

Jan 1, 1973

By Lawrence K. Barker

Crude shale oil produced by underground retorting of Green River Formation oil shale was hydrogasified over a cobalt-molybdate-on-alumina catalyst at operating temperatures ranging from 800° to 1,300° F, pressures of 500, 1,000, and 1,500 psig, and a liquid hourly space velocity of 1.02 volumes of oil per volume of catalyst per hour (Vo/Vc/hr). At a temperature of 1,300° F and pressure of 1,500 psig, 94 weight-percent of the liquid feed was converted to gas containing 72 volume-percent methane. With two reactors in series at a temperature of 1,170° F in reactor 1 and 1,260° F in reactor 2 and a pressure of 1,500 psig, 97 weight-percent of the liquid feed was converted to gas with a methane content of 75 volume-percent. Liquefied petroleum gas (LPG) was hydrogasified at operating temperatures ranging from 500° to 1,400° F at a pressure of 500 psig over a cobalt-molybdate-on-alumina catalyst. Similar experiments were made with an empty tubular reactor. The data indicate that gasification reactions in the presence of a cobalt-molybdate catalyst change from predominantly a catalytic (carbonium ion) reaction to predominantly a thermal (free radical) reaction at temperatures greater than 1,100° F. The data also indicate that a reaction temperature of 1,350° F is necessary at the space velocities used in this investigation to make a synthetic natural gas (methane content of 90 volume-percent) from in situ crude shale oil.

Jan 1, 1975

By A. E. Nehrenberg

THE mechanism by which austenite forms in steels has received a great deal of attention in the literature in past years.'-'* Our present knowledge concerning this mechanism has been recently summarized quite concisely by Bain and Vilella,1 while a few years ago the literature was carefully reviewed by Roberts and Mehl.² The consensus is that any ferrite-carbide interface is a potential site for the nucleation of austenite during heating above the Acl temperature, and that the new austenite generally grows freely to produce approximately equiaxed grains, whether the carbides are initially present in the lamellar or the spheroidal form. In the case of eutectoid steels, growth of the new grains of austenite continues until contact is established with other grains. Then growth stops and an initial austenite grain size is established which does not change until the heating is continued to some high temperature at which grain coarsening begins. In the case of pearlitic steels which are not of eutectoid composition, the proeutectoid ferrite or carbide may interfere with the growth of the austenite if the temperature is not above that designated the A63 or the Acm, respectively. Although a large amount of work has been done to establish the mechanism of austenite formation in steels, it became clear to the present author while he was studying the transformation characteristics of a new 0.25 C Mn-Si-Ni-Mo hypoeutectoid steel" that the manner in which austenite grows in steels depends upon some factor, or factors, not previously considered. This was indicated by the fact that when this steel in the spheroidized condition was heated above the Ae1 temperature the new austenite which was formed did not envelop the carbides and grow in an equiaxed manner as described by Bain³ or spheroidized steels. Instead, in this steel, the austenite was observed to grow much more readily in certain directions than in others with the result that at temperatures within the Ac1-Ac³ ransformation range the austenite grains were acicular in shape. The excess ferrite was also found to be acicular with the distribution of these phases being such that a lamellar pattern was developed. This unusual directional growth of austenite in this new steel initially in the spheroidized condition is illustrated by fig. 1. A search of the literature revealed that this type of growth was not necessarily peculiar to this steel for similar microstructures had been observed by other investigators.4-8 However, the full significance of these microstructures does not appear to have been appreciated, and no work has been done to determine the conditions responsible for this directional growth of austenite or to arrive at an understanding of it. It was for this purpose that the work described in the present paper was carried out. Material: During the course of this investigation a total of 15 steels was studied. They consisted of hypoeutectoid, eutectoid and hypereutectoid carbon steels, and hypoeutectoid and hypereutectoid alloy steels, all of which were obtained in the annealed condition from commercial warehouse stock. As received, the carbon and alloy hypereutectoid steels had microstructures which consisted of spheroidal carbides in ferrite, whereas the eutectoid steel and the hypoeutectoid steels were pearlitic. The grades of steel represented were 1050, 1080, 10110, 3310, 4140, 4340, 4615, 6145, 8620, 9260, 9442,

Jan 1, 1951

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Mine Superintendent or Manager. Age 34, graduate mining engineer. Thirteen years' practical mining experience in Canada and United States holding responsible executive positions, mining engineer and mine superintendent. Experience in iron, gold, copper, and pyrite mining. Best references, can go anywhere but prefer location in Canada. At present engaged but desire change. Minimum salary $3600. A-2845. Manager or Superintendent for producing mine or new development. Institute member, 25 years' experience, mining, wet concentration, construction and examination. A-1173. Mining and Metallurgical Engineer. Technical graduate, 11 years' practical experience principally with copper mining, milling, smelting, and electrolytic refining, now holding an engineering executive position, wishes to change to place of more responsibility and opportunity. A-3785. Engineer with 11 years' experience in mining, civil, and industrial engineering, desires to become connected with a strong organization requiring services of thoroughly trained man. Graduated from University in 1909, now employed, having been with present organization nearly 7 years. Available about Sept. 15. A-4071. Metallurgical Engineer, age 31, married, A. M. and Ch. E.; 7 years' teaching and industrial experience, of which 3 ½ have been with electric furnaces. Desires position in investigative or executive work. Minimum salary $3000. A-4176.

Jan 9, 1919

[MINING AND EXPLORATION DIVISION Established as Mining, Geology and Geophysics Division, Sept. 27, 1949 Name changed February 19, 1958. Lyman H. Hart, Chairman Robert J. Lacy, Assistant Chairman Vice Chairmen: John C. Wangaard, Membership J. M. Ehrhorn, Program John G. Hall, Publications C. E. Nelson, Secretary American, Smelting and Refining Co. 120 Broadway New York 5, New York Editor, Rock-in-the-Box: J. W. Chandler.]

Jan 1, 1961

By G. L. Fitzpatrick

A portable optical instrument for performing multispot laser vibrometry is described. The instrument is capable of measuring arrival times, surface motion frequency, and surface velocity and displaying these quantities in various useful ways. Sigma Research is currently pursuing the development of such optical measuring systems for the evaluation of structures in rock by non-contact interferometry methods. This work was sponsored by the U.S. Department of Interior (U.S. Bureau of Mines) under a Small Business Innovation Research (SBIR) contract number J0145075. The goal of the work was to develop a portable tripod mounted measuring system which can be set up at arbitrary distances (up to 30 meters) from a surface and project four in-line laser sample beams on this surface. A light receiving telescope gathers the scattered light from these four spots and provisions are made to mix this light with a reference beam from the laser. Four photodiodes are employed to determine the resultant interference signals which characterize the motion (particle velocity, frequency, amplitude) of the four illuminated spots on the surface under sudy. Information of this type can then be used to characterize the elastic or mechanical properties of the surface in question. In some cases (if more than four spots are involved) this surface information could be back propagated to draw inferences about the internal state of the material volume bounded by this surface.

Jan 1, 1987

By Joram M. Amir

Even when they are cased! [ ] In bored piles, as well as in drilled shafts, and in caissons too, defects will occur! [ ]

Jan 1, 2001