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By B. W. Gandrud

This is the third report published by the Bureau of Mines concerning the washability of Black Creek coal. Both of the former reports5/6/ dealt with the Black Creek coal at the Bradford mine, Dixiana, Ala., near the northeastern extremity of the Warrior field, whereas the present report is based on float-and-sink tests of coal from what is presumably the Black Creek bed near the southern extremity of the field. Although the Yolande Coal & Coke Co., owners of the property at Yolanda No. 6 slope, consider this opening to be on the Black Creek bed, the authors do not feel that there is as yet positive proof that this correlation is correct. There has been little or no development of the Black Creek bed in the Yolande Basin in the past, and a posy-tine identification of the bed at Yolande No. o will have to await further exploration and development. The Yolande No. 6 is an exploration slope 3/4 mile north of Rockcastle, Ala. The slope is approximately 400 feet from top to bottom on a dip of 18° As fax as the authors can ascertain, coal has never been produced commercially from the Black Creek bed in the southwestern part of the Warrior field. Exploration work in the past has indicated that the Black Creek coal in. this area is extremely friable and high in sulfur. Extreme friability would naturally discourage its' use as a domestic and railroad fuel, and high sulfur content would be a disasvantage in its use for coking coal. The present study of this coal has been made with particular reference to sulfur elimination on the assumption that it would make a good coking coal provided enough of the sulfur could be eliminated by washing.

Jan 1, 1939

By N. P. Mahumapelo

This paper is based on a study to determine the potential beneficiation opportunities for marble from Griekwastad in the Northern Cape Province. The marble was characterized mineralogically by X-ray diffraction. Major and trace elements were determined using inductively coupled plasma-optical emission spectroscopy. The sample was crushed, and the crushed material beneficiated by tumbling and polishing. The resulting beads were incorporated into a variety of jewellery and other decorative items. It is concluded that the beneficiation of Griekwastad marble presents a good opportunity for value addition and job creation, provided that an effective marketing strategy for the products can be developed..

Jan 1, 2014

Hydraulic backfill is generally retained in stopes using permeable barricades. Mitchell et al (1975), Mitchell (1992) and Grice (1989) have shown that under normal drainage conditions, barricades experience low levels of loading. Cowling et al (1988) have also shown that barricades are susceptible to piping failures if excess water has ponded on the upper backfill surface and if leakage of backfill from the barricades has occurred. During 1997, six hydraulic backfill barricades failed in four different Australian mines. Fortunately, in each case, the quantity of backfill slurry released was small, and no injuries to personnel nor damage occurred. Detailed investigation of two of the incidents showed that the primary cause of failure could be attributed to the delivery of excess quantities of transport water from the low-density slurry. For each of the incidents investigated there was evidence of the development of piping failures, which resulted in hydrostatic loading conditions on the barricades from the ponded water on the upper backfill surface. The circular failure surfaces in the barricades were characteristic of the application of point loading conditions. This paper discusses the circumstances that led to these incidents and analyses the modes of failure. The standards for the safe operating of hydraulic backfill systems are reviewed along with requirements for ongoing management and control. The design requirements of barricade construction are analysed and some appropriate guidelines introduced.

Jan 1, 1998

By Hugh P. Godard, K. Winslow

"AbstractA number of panels of various aluminum alloys in different combinations and secured by steel and three types of aluminum rivets were exposed underground at two locations in a Northern Ontario gold mine for two years and then examined to determine the extent of corrosion. The results indicate Alcan 65S-T to possess considerable advantages over Alcan 178-T, which has been employed in the construction of light skips and cages with considerable success for almost twenty years. Information on the behaviour of these alloys when used with steel rivets and in mixed combinations with themselves was obtained.IntroductionBy the complete substitution of aluminum alloys for steel in the fabrication of mining skips and cages, their weight can be reduced as much as 50 per cent. Lesser savings are possible though its savings are possible through its plates, doors, reinforcing members, etc. Reduced weight leads to economy through increased hoisting efficiency.For a new installation, the basis of design is the rate of production, which thus fixes the live load to be hoisted per trip. A lighter skip permits the use of a lighter rope and a smaller hoist. In deep shafts with high-speed hoists operated in balance, the power required for accelerating is considerable. The hoist size is determined by the weight of skip, load, and rope plus the force required to accelerate or decelerate these three elements A light skip may result in a considerably lighter rope. This is important because, even though the skip can be completely balanced this is not true of the rope. Partial balancing is possible, but conical hoist drums or other devices for this purpose are costly; thus a smaller rope results in a smaller hoist, with consequent general reduction in cost of the whole installation. A reduction in power consumption is also obtained as a result of keeping to a minimum the amount of unbalanced load and the weight of all moving parts which must be accelerated."

Jan 1, 1950

By Mike Higgins

"Data management is emerging as a major concern for miners. Engineers today are faced with anextensive array of data from varying sources, and are required to consolidate and analyse thisinformation to produce an effective and efficient mine plan. The viability of a mining operation canbe dependent on the outcomes of this process. With so much at stake, it is no surprise that mostengineers prefer a standard approach to blasting which is designed to minimise risk rather thanoptimise performance."

Jan 1, 1998

By D. J. Scarpato

"Slope construction in shale can present some interesting challenges for geotechnical design engineers and contractors alike. There are challenges that can be expected and designed-for; however, all too frequently, such challenges manifest themselves as “surprises” in the field. Common constructability challenges can include those such as drill hole deviation during drilling for controlled blasting; and, excavation slope instability arising from inconsistent perimeter control drilling. Drill hole deviation results from the cumulative effects from both drilling mechanics and rock mass conditions. Once a hole has initiated the deviation trajectory, it is difficult to rectify drill steel position. Although such challenges are not necessarily unique to shale, they are often exacerbated by weak, weathered and transversely isotropic nature of bedrock conditions. All too often, the working assumption is that shale is “soft” and easily excavatable; however, this blanket assumption can prove to be costly. This paper is intended to provide design professionals and contractors with the practical considerations needed to avoid the “surprises” associated with drill hole deviation, and minimize the potential for costly claims.INTRODUCTIONFor all the slopes that have been excavated worldwide, and for such advancements in excavation technology and field characterization, one might be tempted to believe that the industry almost has slope development down to a science. This is frequently not the case, especially for weak/weathered and anisotropic bedrock. Excavation contractors are still pushed to the limits of what their technology can achieve, and engineers are all too often called to the field during construction, to make potentially risky onthe- fly decisions relative to excavatability, short and long-term slope stability, and project safety. Although there have been a host of other research papers and journal articles that have been written on the subject of deviation over the past 30 years (Brown, Geen, Sinha, 1981), the problems associated with drill hole deviation are still all too frequent. This fact is especially true for civil engineering surface excavations in bedrock."

Jan 1, 2015

By Tyler Lahti, Peter Borgacci, Mary Jane Ferraro, Prakash Nadesparan

Toronto Tunnel Partners (TTP), under contract to Metrolinx/IO, is constructing new twin rail tunnels under the Highway 401 & 409 interchange to accommodate additional tracks to support the GO Expansion program for future two-way, all-day service. The new tunnels are being constructed using the Sequential Excavation Method (SEM) and utilize a tunnel pre-support system consisting of a series of 800 mm diameter steel pipes to form a pipe canopy. The pre-support pipes were installed with an Auger Boring Machine (ABM) in four separate headings; one heading from each of the tunnel end portals, and two from a shaft in the middle of the highway. To facilitate the auger boring operation, a custom steel reaction frame was required to counteract the thrust from the ABM at the portals, and a temporary shaft structure was installed in a narrow median space of the highway. The installation of the pipe canopy had to overcome challenges including removal of obstructions, alignment issues, and controlling settlements to the highway surface. This paper discusses the purpose of the pipe canopy, design and installation of the temporary shaft and structures to support the auger boring operation, the experience of the contractor during the installation of the pipes, and brief overview of the experience tunneling below the pipes.

Jun 13, 2021

By G. R. Gardner, D. H. Davis

INCREASING realization of the importance of dust control, and the recommendations of various agencies, have led the mining industry to become actively concerned with this problem. The background and necessity for adequate dust-suppression measures have been discussed in a number of publications, including those of the U. S. Bureau of Mines, and the use of spray water to reduce dust at the face and on roadways has been recommended. The problem resolves itself into obtaining adequate dust reduction at a reasonable cost. Inasmuch as the term "adequate dust suppression" has never been clearly defined, nor have permissible limits of dustiness (in terms of dust count) been established, it is apparent that any method selected may be required to meet additional demands. Until the industry has been given some indication of permissible limits of dustiness, no permanent solution is possible. Progress will be somewhat handicapped until such information is available. In addition, dust reduction must be obtained without the addition of any excessive moisture to the coal, since consideration must often be given to: I. Quality standards, particularly reduction in heat value. 2. Handling characteristics, particularly in regard to unloading from railroad cars and bins. 3. Application of dry methods of coal cleaning. 4. Necessity for fine screening within specified limits of oversize and undersize. Little detailed information is available as to the advantages and disadvantages of the several methods of water distribution, the location and protection of sprays, operating data on pressure, quantity of water, and so forth, and results obtained. In 1940 an investigation was undertaken to determine and evaluate the principal factors involved. This paper constitutes a progress report on this work and cannot in any way be regarded as complete on any one of the several phases. CLASSIFICATION OF DUST SOURCES The various sources of underground dust may be classified as primary or secondary. A primary source is one associated with appreciable degradation of size, that is, where the greater part of the actual fines capable of becoming air-borne dust are produced. A secondary source may be considered as one in which the greater part of the fines have been produced at some previous operation and are in such condition that they can be dispersed as air-borne dust. These conceptions appear to be of practical significance, as experience indicates that when dust is controlled at the primary sources the importance of secondary sources is minimized. For these reasons, investigations to date have been concerned principally with the primary sources of dust, and this paper is concerned particularly with one of these-namely, undercutting. In accord with the foregoing definitions, the sources to which the following opera-

Jan 1, 1942

By G. M. Card, K. D. Card, B. V. Sanford

The Canadian Shield and its extensions are traversed by an orthogonal system of north-west and northeast trending arch-style uplifts. These basement arches were formed by repeated vertical movements along pre-existing structures during compressional and extensional tectonism connected with events in surrounding Proterozoic and Phanerozoic orogens and ocean basins. The arches in?uenced patterns of sedimentation and tectonism in the intervening epicratonic basins andmarginal platforms throughout the Proterozoic and Phanerozoic. Movements on the arch structuresalso triggered minor magmatism and controlled the location and timing of alkalic rock-carbonatite, kimberlite, and related intrusions in the Canadian Shield, the Western Canada Sedimentary Basin, and West Greenland.

Jan 1, 1997

By M. B. Cooke

 An analytical method for the determination of the gum-forming material in gasoline has been developed by the Bureau of Mines, during a study now in progress to determine the best rays for elimination of such constituents from gasoline. This method is similar in principle to that previously described by Smith and Cooke, which involved evaporation of e semple of gasoline in a small glass dish. The evaporation was started on an actively boiling steam bath and completed in an air oven at 105°C. In the improved method described below, the steam bath has been replaced by a steam heated oven in which an inert atmosphere is maintained. Air is ex- cluded from the oven, consequently the precision of the determination is increased. Furthermore, evaporating dishes different from those previously described may be used.

May 1, 1925

By David A. Lipton

In 1980, the U.S. Bureau of Mines conducted a mineral survey of the 23,500 acre Garcia Mountain RARE II area (No. 5107) in the Los Padres National Forest. Bureau of Mines data indicate a low potential fur gold, silver, and mercury resources. Twenty-nine placer samples, representative of small yardages, showed small amounts of gold or other economic mineral values. Mercury deposits in faulted siliceous rocks in the Franciscan Formation occur north of the area. Similar rocks are in the southwest part of the study area, but apparently contain no mercury deposits. Geothermal and oil and gas potential is low.

Jan 1, 1982

By V. F. Zackay, W. A. Goering

ALLOYS of iron and aluminum up to 35 wt pct aluminum are single-phase solid solutions, and are of potentially wide applicability.1-3 In spite of early and continued interest1-4 little progress has been made until recently in the preparation and evaluation of sound alloys containing more than 6 wt pct aluminum. Vacuum-melting techniques for the production of ductile Fe-A1 alloys have been described recently.1-7 A. procedure for air melting these alloys is presented here. Low-carbon iron is induction melted without a slag in a rammed magnesia crucible. At the beginning of melt-down, aluminum pig (99.95 pct Al), charged in a clay-graphite bottom-pouring crucible is placed in a pot furnace at 1800°F. The primary deoxidation of the molten iron after melt-down is effected by the addition of 0.1 pct aluminum and 0.5 pct manganese. (Hilty and Crafts" have reported a significant increase in the deoxidation efficiency of the aluminum and manganese combination over that of the aluminum alone.) A more drastic deoxidation designed to reduce the oxyen content to the lowest possible level is accomplished by plunging metallic calcium to the bottom of the melt. This is done by wiring small cubes of the metal to a steel rod. A circular shield larger than the diameter of the crucible opening is attached to the rod so that any spa'ttering of the molten metal will not endanger the operator. Since the temperature of the molten metal is above the boiling point of calcium, the bath is vigclrously purged by calcium vapor. It is believed that the calcium-vapor treatment permits a homogeneous distribution of calcium in the melt. Owing to the vigor of the reaction the temperature of the molten metal should be kept below 2900°F prior to the calcium addition. A total of 0.05 pct calcium is added in two stages in this manner. The second calcium deoxidation is made just before charging the molten aluminum into the iron, in order that an excess of calcium be present for the remainder of the melt. The aluminum, which has been removed from the holding furnace, is then hydrogen degassed by bubbling chlorine through a quartz tube immersed in the molten aluminum. The hydrogen-chlorine reaction is an exothermic one preventing the solidification of the aluminum during the 5-min chlorination. Approximately 0.1 pct calcium, based on the amount of aluminum, is then added to the aluminum. A further excess of calcium is introduced into the melt in this manner. The oxide dross is removed, fluorspar is added to the molten iron, and the molten aluminum is poured through the fluorspar slag. The fluorspar should be dried thoroughly prior to its use, as any water present will react with the aluminum. Aluminum oxide formed during the pouring operation reacts with the fluorspar slag to form gaseous aluminum fluoride and calcium oxide. A forced-draft ventilating system is required for this operation as aluminum fluoride is toxic. As soon as the molten aluminum has been added, vigorous manual stirring of the melt is required because the slag-aluminum oxide reaction is highly exothermic and tends to take place near the top of the melt. The combination of high temperature and the slagging action of the fluorspar quickly erodes the crucible at the slag line if the aluminum is not stirred uniformly into the melt. It has been found that at least 4 min of manual stirring combined with induction stirring are necessary to ensure homogeneity. The power is shut off 1 min prior to pouring to allow metal and slag to separate. As much slag as possible is removed from the melt, which is then poured directly into cast-iron molds. A mold wash of aluminum oxide is used to prevent ingot sticking. For slab ingots which are to be rolled into sheet, a carbon-tetrachloride vapor atmosphere or a chlorinated-pitch mold wash is desirable, as the aluminum oxide formed in the pouring operation is subsequently removed by the chlorine in the presence of carbon." As in vacuum melting, a pouring temperature of about 2900°F is recommended. Adequate hot-topping is important as iron-aluminum ingots are subject to very deep piping. Ingots are removed from the molds and buried in vermiculite, where they are allowed to cool slowly to room temperature. The ingots are radiographed,

Jan 1, 1959

By K Williams, A Lavrinec, V Gurung, D Ilic

The moisture content of iron ore during handling can range from the dust extinction moisture at the point of arrival at the port to the transportable moisture limit at the point of loading ships for maritime transport. Moisture content and ore composition, specifically fines content, have a large influence on ore flowability. Typically, elevated moisture can result in bottlenecks, downtime and lost productivity due to build-up, conveyor carry-back and blockages, increasing maintenance costs. On the other hand, low moisture can result in increased dust emissions influencing the environmental footprint and product losses. Managing the use of water across the supply chain is therefore critical for service life of equipment, productivity, but also has environmental and social impacts, affecting the social license to operate. Previously, experiments have shown that oscillations induced in iron ore during handling and transport can result in movement of moisture through the ore. This kind of moisture migration depends on the nature of these oscillations, such as the undulation of idlers during conveying, the inherent ore properties and the initial moisture content. Moisture has been observed to move either upwards and/or towards the bottom of the burden. These effects can be exploited to remove excess water from the ore influencing handleability and operation, however, the actual mechanisms of moisture migration are currently poorly understood. The study presented herein involves the use of simulation to examine moisture and ore interactions. Simulations using discrete element method (DEM) and coupled with smoothed particle hydrodynamics (SPH) are implemented to investigate the behaviour of moisture in wet ore in the presence of oscillation. This is conducted at a fundamental level first using glass beads and water which is then compared to iron ore at high moisture content. The results of the modelling are discussed in view of experiments conducted.

Sep 18, 2023

By B. I. Hop

The f10wfield set up by the standard Hydro gas purging unit has been predicted by a numerical model. In addition turbulent trajectories of gas bubbles released from the rotor are predicted. Here the deposition rate of inclusions on the bubble surface is allowed to depend on local conditions. Bubbles passing regions with strong pressure gradients, such as close to the rotor, will experience large slip velocities and large deposition rates. This model can deal with any distribution of bubble sizes and inclusions. The results found from the multidimensional flow predictions are discussed in relation to what can be obtained from a much simpler metallurgical engineering approach. The differences between these two approaches to predict the same process will be discussed. The model predictions are compared to experimental results for removal of SiC-particles from aluminium.

Jan 1, 1996

By Chuck Crowell

ISO Standards ?Provide Information to Address Commercial and Safety Needs for Standardization: ?Definitions and Terminology ?Test Methods ?Performance Criteria ?Conformity Assessment Process ?Developed by Global Experts ?Promote Global Harmonization

May 1, 2013

By T. A. Lloyd

The use of tank cells over the years has provided a means for low cost, space efficient, extra capacity in existing flotation circuits. In some cases, new plants have selected tank cells as the machine of choice. Typical tank cells use high efficiency impellers for mixing, which results in low power draw. Unfortunately, these mixers have poor aerating characteristics that compromise metallurgical performance. This has all changed with Outokumpu's new flotation concepts. Outokumpu has recently developed the HG or High Grade flotation cell that can provide higher recovery with better selectivity while maintaining the simple operation of conventional cells.

Jan 1, 1993

By D. Sethuram, P. G. Koppad, S. Iyengar, R. Shobha

TiB2 and CeO2 particle-reinforced Al6061 hybrid composites were manufactured using stir casting and hot rolling techniques. The base alloy and composites were hot-rolled at 500ºC and a 50% reduction was achieved through 12 passes. The effect of varying TiB2 and CeO2 particle additions on the microstructure and mechanical properties of the Al6061 matrix was studied. Scanning electron microscopy showed uniform dispersion of both the reinforcements, with good interfacial bonding. Microhardness and tensile properties like yield and tensile strength were found to be higher for hybrid composite with 2.5% TiB2 and 2.5% CeO2 compared to Al6061 alloy and other hybrid composites. The increased tensile strength is attributed to good dispersion and interfacial bonding between the particles and Al6061 matrix. Fracture analysis using a scanning electron microscope revealed ductile fracture for the Al6061 alloy and mixed characteristics of ductile-brittle fracture for hybrid composites

Oct 1, 2021

Interest in those physical properties of minerals which might be used to good effect in prospecting is not new. Early in the nineteenth century attempts were made in th'e Cornish mines to measure the natural electric potentials set up by chemical changes proceeding in the lodes. The distortion of the earth's magnetic field by bodies of strongly magnetic iron ore received early recognition in Sweden. Treasure-finders, working on the principle of electrical induction, appear to have been invented about eighty years ago, though were probably not then applied to mineral exploration. By the end of the nineteenth century Eotvos, a Hungarian physicist, had constructed a highly sensitive type of torsion balance capable of measuring the minute distortions in the earth's field of gravitation resulting from variations in the density of the materials composing the crust. During the first decade of this century he demonstrated its value in tracing rock-salt deposits in virtue of their low density compared with the surrounding rocks. Geophysical prospecting began to be recognised as having a very definite value and its development gathered momentum. Its great expansion took place after the 1914-18 war, when its value in oil exploration was amply demonstrated, and this expansion has continued to the present time and shows no signs of abating.Divisions of Applied Geophysics.The four main divisions of applied geophysics are electrical, magnetic gravitational and seismic. With the importance of ores of radio-active metals, one might add to these a radio-active division. The first two are more important to the field of mining, but techniques based on gravitational attraction have their uses in particular cases. Seismic methods are not generally suited to the exploration of metallic ores, but have proved of enormous value in the search for petroleum. With vast quantities of oil as the prize, more money has been lavished on the deve10pment and practice of these methods than on all the others put together.Geophysical Prospecting Methods.Geophysical prospecting methods may be used to detect a mineral deposit directly in virtue of differences in the intensity of some physical attribute common to it and the enclosing country rock. Examples of this are the detection of rock-salt by gravity measurements, or of iron ore by magnetic methods. Of much wider application, however, is the indireot approach in which the aim is to determine, by geophysical means, the geological structures controlling the disposition of mineral deposits. These structures may be partly known from geological work, in which case geophysical methods are useful adjuncts. Where, because of an 'unbroken cover of overburden, no useful geological information presents itself, scout drilling or geophysical prospecting are the only alternatives. Overburden is here intended to mean any covering material not, involved in the structures controlling the mineral deposits. Prospecting for petroleum amounts to the detecting of favourable reservoir structures, and as the chief types of such are the same the world over...

Jan 1, 1950

By Don K. Smith

The northern zone of the Indus Basin comprises a vast area of essentially level land in West Pakistan which is irrigated by means of a complex system of canals that distribute more water to more land than any other irrigation system in the world. In spite of the development of this extensive irrigation system, production of food and fiber has not met the requirements of the country. The major reasons that crop production has not reached anticipated levels are the lack of adequate irrigation supplies and effective subsurface drainage. As a result, yields per acre are among the lowest in the world for areas where irrigation is practiced, and many thousands of acres of valuable crop land have been removed from production or are seriously affected by salinity and waterlogging. To rectify the problems of irrigation supply and drainage the Government of Pakistan has undertaken a program of Salinity Control and Reclamation which is being administered by the Water and Power Development Authority. The Authority retained Tipton and Kalmbach, Inc. , of Denver,, Colorado as Engineers for the program in the northern zone of the Indus Basin. -This program consists of the construction of about 30, 000 irrigation wells to provide drainage for waterlogged lands and full irrigation supplies, including leaching requirements, for; all cultivated lands. The program will ultimately ensure the productivity of 20 million acres and will involve an annual pumpage from ground water storage of nearly 40 million acre-feet of water. The value of the crops produced when the program is in full operation will be 4 to 6 times the value of the crops that could be produced without the benefits of this program.

Jan 1, 1967

By C. K. Kocsis, S. Hardcastle

Mine ventilation, requires electricity to operate the fans and fossil fuel for heating. Typically, this accounts for approximately 40% of the overall underground energy consumption. This is considerable, and one of the major causes of this expense is that most mine ventilation systems are designed for the "worst-case-scenario" with respect to ventilation demand, which is commonly dictated by diesel equipment usage. Once designed, mines tend to operate their ventilation system at this peak level despite their exceeding day-to-day development and production needs due to lack of appropriate ventilation controls. In underground metal mines, TeleminingTM, which includes the tele-remote operation of mobile development and production equipment from surface, will change the mine design criteria including its support infrastructure such as the ventilation system. With the removal of machine operators to surface control rooms, conventional ventilation systems designed to dilute and remove pollutants can become redundant. Depending on the ultimate need for ventilation, its cost in automated mines with tele-remote equipment operated from surface will be lower than the cost of ventilation in conventional mines. These cost savings, which could be significant, would not only come from the ability to reduce the amount of ventilation in the mine, but also through the capacity to automate its distribution. This paper provides an indication of the new airflow requirements in stopes and dead-end developments for the tele-remote and automated mining processes based on climatic modelling. Furthermore, this paper makes a cost benefit analysis by comparing the ventilation system operating cost of a conventional underground metal mine based on the mobile diesel powered equipment design criteria with the newly redesigned ventilation system operating cost of an automated mine based on the "heat management" design criteria.

Jan 1, 2002