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By D Reid, A Fourie, J Ayala

This paper discusses cone penetration test correlations for loose gold tailings that were developed within a critical state soil mechanics framework. The development of a new calibration chamber for cone penetration testing that consists of a modified triaxial cell is described. Some of the early development and commissioning issues that were encountered, as well as the solutions adopted are outlined, including the system to prepare the samples and to acquire high-quality data from the testing. Also, the triaxial laboratory testing required to achieve the critical state line is described, including some of the basic precautions considered necessary as good practice. Additionally, the system adopted for volume tracking of the calibration chamber sample is described, which is essential for ensuring a reliable state parameter comparison against the acquired cone penetration test data. Finally, some laboratory test data from the calibration chamber is plotted against the soil behaviour type charts currently available from various authors.

Jul 1, 2021

By Arthur Laing

"IT is indeed a pleasure to have the opportunity of addressing this group today. Not only does it give me the opportunity of meeting with representatives of what is considered by many to be the most dynamic segment of industry in Canada today, but it also allows me to talk about a subject of para-mount interest to myself, the development of the North, and to explain, if even only briefly, some of our beliefs and hopes in this regard.It is inconceivable that all lands north of the 60th parallel, representing 35 per cent of Canada's total land area, which we believe contain a great natural resource potential, will remain as an undeveloped portion of Canada. The re-sources are there, although the people and private industry are as yet not there in sufficient numbers.It has been estimated that in the west and north of Canada there are 1.6 million cubic miles of sedimentary rocks. Of this figure, 342,-000 are thought to lie in Alberta, 115,000 in British Columbia and about 1 million cubic miles are thought to lie in Canada's northern regions, the bulk in the Arctic Islands. On the basis of apparent volumes of sedimentary rock, we estimate that as much as 13 billion barrels of petroleum may lie beneath the permafrost of the North-west Territories, another 3 billion barrels in the Yukon Territory and 33 billion barrels in the Arctic Islands. This is, indeed, a rich and elusive prize, and one which must be sought with a view to fulfilling demands on the production of petroleum."

Jan 1, 1966

By W. Spencer

An examination is made of quality standards in castings produced by the South African foundry industry, and some examples are given of the consequences of poor quality to the user. Corrective measures are suggested.

Jan 1, 1981

By Braden Lusk

The problem of predicting damage in densely developed areas due to incidental or malicious explosions is one of considerable importance to local, state, and federal governmental bodies. The difficulty of making such a prediction is confounded by the urban canyon phenomenon as the shock wave intensifies or rarefies depending upon the particular arrangement of buildings. The specific method detailed herein used a Computational Fluid Dynamics solver, ANSYS AUTODYN, to operate on Geographic Information Systems data, ArcGIS, which captured the geospatial relationship between the various buildings in downtown Oklahoma City, prior to the Murrah Building bombing. The model of Oklahoma City was first developed using the building footprints and elevations provided by the ArcGIS database. Due to the sheer size of the problem, the model was then subdivided into annular zones of increasing distance from the center of the blast. Each subsection was then solved using an Euler model in a cascading fashion with the output of the preceding model forming the input of the present model. To further reduce computational time, the size of the Euler nodes was increased at each stage as the section area increased. Due to the loss of precision in capturing peak pressure values when using larger size nodes, it was necessary to perform a transformation on the results using one dimensional wedge calculations with higher precision. The Murrah Building bombing event was an excellent case study due to its available ArcGIS data and the level of documentation of damage to surrounding structures due to the blast. The results from the staged CFD calculation were then used to develop a damage potential contour map. The documented incidents of damage in the area surrounding the Murrah building were then compared to the model generated damage potential contour map. Copyright ©

Jan 1, 2010

By G. R. Yourt

"Generally speaking the usual approach for controlling dust is three-fold:1. Suppress the formation of dust at the source.2. Confine dust that cannot be suppressed.3. Dilute and remove dust that cannot be confined.This discussion will be concentrated on the second approach, namely, confining and disposing of dusty air.Dust BehaviourBefore delving into actual design principles a brief discussion on behaviour of dust should be helpful. For prevention of silicosis only respirable dust, ranging in size from < 0.5 to 5u needs to be controlled. As particles of this size have insignificant mass and momentum they follow air movements very closely. Consequently if contaminated air around dust sources is confined within enclosures and leakages maintained, strongly indraft dust is automatically controlled and capture velocities are of no concern.Dust SourcesAt metal mining operations ore is prepared for wet concentration by crushing it to mostly <3"" in size. This usually involves a jaw crusher, one or two cone crushers, one or more screens and several conveyors. Dust is actually produced only by the crushing action but it is liberated also when numerous fine particles contained in the ore stream are dispersed by surges and vibration at the discharge of the crushers, screens and headpulleys of conveyors. Furthermore, dust is dis¬persed when the slime adhering to the underside of the return portion of belts becomes dry and is rendered airborne by vibration and by cleaning floors especially where the slime has dropped."

Jan 1, 1971

By R. V. Ramani, A. S. C. Owili-eger

The quantity of methane emitted into the mine atmosphere and the movement of gas through solid coal and the adjoining country rock are dependent on the physical properties of the medium, boundary con¬ditions, the initial gas pressure distribution, and the combination of natural and mining factors. Functional relationships between these factors are not yet known. Consequently, the development of rigorous mathematical models to predict methane flow into the mine air is difficult and to date no model has been reported which is capable of such a function. Thus far, empirical formulas available for the calculation of gas quantity released from underground sources require too much his¬torical data, not currently available. Again, these estimations are at best only crudely approximate. The numerical methods available have not been made practical enough for industry wide application. Therefore, the development of a relationship amenable to numerical analysis and practical enough for use in the industry would provide the flexibility lacking in analytical approaches. The mathematical models given in equations (7) and (8) are further attempts in presenting practical models for predicting the quantity of methane emission into the mine environment. Equation (7) is the steady state model and equation (8) is the unsteady state model.

Jan 1, 1974

By William E. Greenawalt

IN these days of special legislation for the benefit of various industries one might well consider one branch of human endeavor intimately associated with engineering-that of patents and patent litigation. It is estimated that 85 per cent of all industries in the United States are based directly or indirectly on patents. Most inventors are engineers, and most patent litigation pertains to the engineering industries. It is fitting, therefore, that engineers should be vitally interested in discussing patent affairs, particularly as inventors are not a professional group, and invention is mostly a transitory phase incident to the development of specific industrial problems.

Jan 1, 1937

By K. S. Raja, M. Misra, S. K. Mohapatra

"Ordered arrays of TiO2 nanotubular photocatalysts were prepared by a simple anodization process. Band gap states of the TiO2 were altered by controlling the anodization electrolyte composition and thermal annealing conditions that resulted in enhanced photo activity. These nanotubes were used for reducing CO2 to methanol either by photochemical or photo electrochemical routes. Pd nano-particle loaded TiO2 nanotubes were employed for photochemical reduction of CO2 to methanol that showed a conversion rate of 12 x 10-3 mol m- 2h-1. Carbon modified TiO2-xCx type nanotubes were used as photo anode and Ti as cathode for photo electrochemical reduction of CO2. The potential of Ti cathode was maintained at -0.5 V SCE. The formation rate of methanol was determined as 13 x 10-3 mol.m-2h-1.1. IntroductionGlobal warming due to emission of carbon dioxide is a serious environmental concern. The atmospheric concentration of CO2 is about 384 ppm by volume and about 3 x 1012 tonnes by weight. Burning of fossil fuels and deforestation are the leading causes for increase in the anthropogenic CO2. More than 32 x 109 tonnes of CO2 are released per year (based on 2006 data) worldwide from the fossil fuel. Pumping CO2 from the fossil fuel power plants into deep ocean basin is one of the most discussed disposal options. The other potential option is converting this green house gas into valuable fuels.Carbon dioxide feed stock can be converted into fuels of solid, liquid or gas phase by chemical, electrolytic, photocatalytic and photo-electrocatalytic methods. Reduction of CO2 to fuel form of any phase requires energy. The reduction process should be energy efficient so that we do not spend more energy and emit more (indirect) CO2 in the process of converting CO2. From this point of view, conversion processes occurring at room temperature look attractive.Electrolytic conversion of CO2 into various forms such as methane1, ethane2, ethylene3, methanol4,5, ethanol6, n-propanol, formic acid7, and formaldehyde has been widely reported. The standard equilibrium potential (at pH: 0) for reduction of CO2 to methanol is 0.14 VSHE and to methane is 0.2 VSHE which is thermodynamically more favorable than hydrogen reduction. However, the gas phase reduction is kinetically complex requiring effective electrocatalyst. The major issues with electrolytic conversion of CO2 to useful products are:"

Jan 1, 2010

By D J. Williams, S Islam

Worldwide production of black coal amounts to about 8 billion tonnes. Perhaps 20% of this annual production is washed to improve its quality, generating perhaps 250 million tonnes of coal tailings annually, generally in the form of a slurry. The coal tailings slurry is typically thickened to about 25% solids by mass prior to disposal to a tailings storage facility (TSF), and hence comprise mostly water (about 85% by volume), plus sand, silt and clay-sized mineral particles and carbonaceous material. While the tailings settle and consolidate on deposition in the storage facility, their high moisture content makes them prone to run-out should the tailings dam fail, and makes rehabilitation of the tailings difficult. Hence, it is important to understand the consolidation and shear strength of coal tailings. Laboratory consolidation testing of coal tailings from a slurry to a soil-like state has been carried out in a purpose-built, large-scale, slurry consolidometer, instrumented with load cells and pore water pressure (PWP) transducers. Laboratory vane shear testing of coal tailings produced at different gravimetric moisture contents has also been carried out. The test results have allowed a regression model to be developed relating the peak vane shear strength of the coal tailings to their gravimetric moisture content.CITATION:Islam, S and Williams, D J, 2018. Consolidation and shear strength of coal tailings slurries, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 62–71 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By AIME AIME

MINING geology was granted two sessions, Wednesday morning and afternoon, Feb. 17. The morning session, at which H. Foster Bain presided. first considered Paul M. Tyler&apos;s paper, "Economic Notes on Steel-making Alloys." The elements used in these important alloys are chromium, manganese, molybdenum, nickel, phosphorus, silicon, titanium, tungsten and vanadium. Edward Sarnpson and C. K. Leith asked whether chromite concentrates could be used, Mr. Tyler replying that they could if not too high in iron. G. W. Pawel said that they were used at Niagara Falls, nlixecl with coarse ore. In reply to a question asked by A. O. Hayes, Mr. Tyler said that molybdenum had not affected the price of tungsten. After this discussion, E. S. Moore&apos;s paper on nickel was considered. H. Foster Bain thought that nickel is well controlled and in good hands, technically and politically. The popular stainless steel in America is the 18:8 Cr-Ni metal. In Germany a Cr-Mn steel has possibilities. It is easy to make, cheaper. has better workability, will stand 85 per cent reduction between heats.

Jan 1, 1932

By Andrew S. Prokopovitsh

The Bureau of Mines is concerned with all the approximately 60 industrial minerals, although its research program currently is focused on 10 of them--bauxite, chromite, clay, manganese, phosphate, potash, refractories, sulfur, titanium, and zirconium. To alleviate reliance on imported materials, particular attention is directed to those minerals having a potential for production from domestic resources. Another important consideration is environmental problems associated with the production of industrial minerals, principally in mining and mineral processing operations, The Bureau also is looking at the opportunities to substitute more abundant minerals for scarce raw materials such as rutile, fluorspar, and bauxite. In its overall minerals surveillance, the Bureau&apos;s mining and metallurgical research and development are coordinated with its minerals information activities from which reviews, projections, and forecasts identify the potential for critical disruptions and short supply situations.

Jan 1, 1975

By Girley Ferreira Rodrigues, Crocce Denise Romano Espinosa, Victor Bridi Telles, Eduardo Junca, Jorge Alberto Soares Tenorio

"Steel sector is responsible for the generation of solid waste, liquid and gaseous effluents. The Solid waste are mainly composed of slag, dust, sludge and scrap. The industry generates approximately 650kg of solid waste per tonne of steel. Approximately 10% of this waste is in the form of dust and mud. The basic oxygen furnace dust is a waste generate by steel sector. Each tonne of produced steel generates 10 to 20 kg dust. Thus, the aim of this paper is study the reduction of pellets made with BOF dust using hydrogen and study kinetic during the reduction. The tests were performed in a netzsch thermobalance to obtain the data of lost mass. This loss mass is coming from iron oxides present in the BOF dust.IntroductionThe generation of solid waste is a problem for many companies in the steel sector. The main solid wastes generated are slag, dust, sludge and scrap [1]. Beyond solid waste liquid and gaseous effluents are also generated.The basic oxygen furnace is responsible for 60% of all steel produced. This sector is the second largest generator of solid waste from an integrated steel mill, contributing with 27% of solid waste generated in a plant ( 5-7 million tons of waste generated annually worldwide) [2,3,4]."

Jan 1, 2013

By Frederic Benard

Recovery of selenium and tellurium at Copper Cliff by the Ontario Refining Co. has been previously described by the writer.l During 1935 a new building was erected to house this operation and description of the new plant and process form the subject of this paper. The building, of modern steel and tile construction, covers an area of 5900 sq. ft. with a volume of approximately 166,000 cu. ft. The large monitored center bay is flanked by two smaller outside bays, one of which is devoted to the tellurium section. All equipment, ceilings and upper walls, are treated with aluminum paint, giving good illumination and facilitating good housekeeping, essential from a health standpoint in handling material of this nature. Equipment Layout and type of equipment conforms to the requirements of the process as described below. In the selenium section, storage tanks, neutralizing tanks and precipitators are of steel construction, lead-lined and arranged for gravity flow (Fig. 1). The neutralizing tanks are equipped with water-cooled lead coils for controlling solution temperature, agitation being accomplished with compressed air. The precipitators are provided with mechanical agitators, and sulphur dioxide is introduced into the solution through 1/2-in. lead pipes leading from a manifold attached to the cover of the precipitator. Each precipitator has internal cooling coils and an air-jet exhauster to carry off fumes. Neutralized solutions are filtered in a 29-plate wooden filter press using heavy cotton duck as a filter medium, forced feed being maintained by a Welmet centrifugal pump. Dilute solutions are concentrated by evaporation in a vacuum evaporator, constructed of cast hard lead. Heat is supplied by an outside steam chest operating under 15 Ib. steam pressure. The solution is circulated through the steam chest by a pump of antimonial lead at a rate approximating 400 cu. ft. per min. The evaporator is evacuated by a water-jet condenser that creates a vacuum of 26 in. of mercury under normal operating conditions. The capacity of the vessel is 60 cu. ft. and the rate of evaporation 25 cu. ft. per hour.

Jan 1, 1943

By Frederic Benard

Recovery of selenium and tellurium at Copper Cliff by the Ontario Refining Co. has been previously described by the writer.l During 1935 a new building was erected to house this operation and description of the new plant and process form the subject of this paper. The building, of modern steel and tile construction, covers an area of 5900 sq. ft. with a volume of approximately 166,000 cu. ft. The large monitored center bay is flanked by two smaller outside bays, one of which is devoted to the tellurium section. All equipment, ceilings and upper walls, are treated with aluminum paint, giving good illumination and facilitating good housekeeping, essential from a health standpoint in handling material of this nature. Equipment Layout and type of equipment conforms to the requirements of the process as described below. In the selenium section, storage tanks, neutralizing tanks and precipitators are of steel construction, lead-lined and arranged for gravity flow (Fig. 1). The neutralizing tanks are equipped with water-cooled lead coils for controlling solution temperature, agitation being accomplished with compressed air. The precipitators are provided with mechanical agitators, and sulphur dioxide is introduced into the solution through 1/2-in. lead pipes leading from a manifold attached to the cover of the precipitator. Each precipitator has internal cooling coils and an air-jet exhauster to carry off fumes. Neutralized solutions are filtered in a 29-plate wooden filter press using heavy cotton duck as a filter medium, forced feed being maintained by a Welmet centrifugal pump. Dilute solutions are concentrated by evaporation in a vacuum evaporator, constructed of cast hard lead. Heat is supplied by an outside steam chest operating under 15 Ib. steam pressure. The solution is circulated through the steam chest by a pump of antimonial lead at a rate approximating 400 cu. ft. per min. The evaporator is evacuated by a water-jet condenser that creates a vacuum of 26 in. of mercury under normal operating conditions. The capacity of the vessel is 60 cu. ft. and the rate of evaporation 25 cu. ft. per hour.

Jan 1, 1943

By Rosewell H. Johnson

Discussion of the paper of ROSWELL H. JOHNSON, presented it the San Francisco meeting, September, 1915, And printed in Bulletin No. 102, June, 1915, pp. 1291 to 1294. WILLIAM A. WILLIAMS, San. Francisco, CaI.-A sliding. scale of royalties was proposed to the Department of the Interior in connection with the fixing of royalties to be charged upon oil leases made on the Osage Reservation in Oklahoma. The possibility of evasion and difficulty of enforcement required close inspection to satisfy all interests, particularly in connection with the exemption from royalty on oil to equal maintenance and interest on the junk. Mr. Johnson discusses the block method, the period method, and the cumulative method, and favors the adoption of the cumulative method with a proviso that the wells should be permitted to be pumped until the gross income is as low as the maintenance cost, which would mean exemption from royalty on the smallest wells. He recommends that depth be the variable factor upon which the sliding royalty is based and suggests that on partially developed territory in the Osage, the royalty be one-sixth for oil wells averaging less than 2,000 ft. in depth, one-eighth for wells from 2,000 to 3,000 ft., and one-twelfth above 3,000 ft.; for the rest of the Osage he suggests one-eighth above 2,800 ft. and one-twelfth below that depth. The net result, if Mr. Johnson&apos;s suggestions had been accepted in the Osage, would have been to reduce the then existing rate of royalty and considerably increase the cost of administration. The difficulties in determining the size of wells to be exempt and the possibility of obtaining oil at different depths in the same well might lead to complications which are avoided by charging a flat royalty as now universally charged throughout the United States. It is not uncommon to reduce the royalty when the production of the wells becomes unprofitable at an existing rate of royalty, accomplishing very much the same results as Mr. Johnson has attempted to accomplish by the cumulative royalties, and probably in a manner far more satisfactory to the operator and the lessor. A. C. MCLAUGHLIN, San Francisco, Cal.-The net revenue of the well depends, first, on the cost of production; second, on the amount of oil produced; therefore it would be impossible under Mr. Johnson&apos;s system to set a royalty which would be fair to all concerned. If it is impossible to set it at the beginning, it is certainly further impossible to do it from day to clay. I think it is entirely impracticable of application.

Jan 12, 1915

By Axel Preusse

Stowing or waste fill is common in the German mining industry since the beginning of mining activities, With increasing mechanization, flat and gently inclined seams (0 -- 18) were mined. These mines were located within the densely populated areas close to important infrastructures such as industrial complexes, roads, highways, railroads, rivers and canals. These buildings and infra¬structures were rarely protected against subsidence influences and other ground movements and dump capacities close to the mines were exhausted. For subsidence reasons and because of the low dump capacities pneumatic stowing methods were continuously developed and used in German longwalls until 1997. Due to techni¬cal standards and because of some restrictions pneumatic stowing in Germany is only used at a minimum seam thickness of 2.00 m and average costs of this method are $20 - 30 per ton. A significant reduction of the disturbance potential and by that a decrease in expenses for subsidence regulations due to reduced subsidence and ground movements could not be achieved. In this paper the experiences with pneumatic stowing in the Ger¬man mining industry are described. Possible subsidence reduction and economic aspects of pneumatic stowing are taken into account.

Jan 1, 2002

By Frank McKinley

This paper discusses the basic requirements covering the area between the initial discovery of a deposit and a decision as to whether or not the deposit will support an economically sound mining venture. The procedure for gaining the necessary information and the sequence of steps is in .some respects parallel to gaining like information on deposits other than the sand type. For the sake of simplicity the stages and sequence are presented as follow: first, the initial reconnaissance drilling; second, the exploration drilling to permit initial ore body estimates; third, metallurgical testing; fourth, the estimate of plant and operating costs; and last, the economic balance. The objective of the reconnaissance drilling is to collect sufficient information to reach a decision as to the advisability of further exploration or the abandonment of the area. This initial phase will comprise, in addition to some drilling, a thorough reconnaissance of the area, a study of the best geological and topographic maps of the region, and a study of any literature available, all under the guidance of a geologist.

Jan 1, 1958

Thermodynamics and kinetics? of the removal of Va elements (As,Sb,Bi) from copper were investigated 1n the fire relining by alkaline carbonate fluxes such as Li 2co3 , Na 2CO3 and K2CO3. The distribution coefficients of As, Sb and Bl between alkaline carbonate fluxes and mo) ten copper were ?obtained at 1200°C under the different oxygen potentials. As and Sb were easily removed from copper to fluxes as pentavalent oxide form. On the other hand, Bi was hardly removed except by a Ll2CO3 flux. The removal rates of Va elements from copper were also measured In the temperature range of 1150°C.- 1250°C. The removal rates of As and Sb were much higher than that of Bi. The removal rates of Va elements showed the same order of the distribution coefficients. The removal rate could be expressed by following equation. (1).

Jan 1, 1987

By Marco Zurco, Claudia M. Mendez, Alicia E. Ares, Carlos E. Schvezov, Carlos M. Rodriguez

"Zinc-Tin alloys were solidified in horizontal form and the obtained results were analyzed. During solidification the distribution of temperatures were measured by using thermocouples located strategically along the length of the samples. From the measured temperatures the following parameters were derived; the local temperature gradient, the cooling rate and the velocities of the liquid and solids fronts. Comparing the structure of the samples and the values of these parameters it was found that the temperature gradient reaches minimum values of as low as - 0.6 °C/cm, and velocities of the fronts of around 0.1 cm/s. In addition, the grain size was measured along the samples. The results are presented and discussed in the frame of the results previously obtained for other alloys.IntroductionGenerally solidification leads to two types of grain morphologies: columnar and equiaxed. The origin of each one has been the subject of numerous theoretical and experimental researches in the field of metallurgy for many years [1-7]. The columnar-to-equiaxed transition, CET, is considered as an object of high technological relevance with respect to the directional solidification of metallic alloys. This structure transition may be sharp or gradual and it has been reported to be dependent on thermal conditions associated with the casting process, including melt convection, heat transfer coefficients at the metal-mold interface, growth rates, thermal gradients, cooling rates, transport of solute, alloy composition, melt superheat, mold temperature, mold design, casting size, casting geometry, and the concentration of nucleating particles. As a consequence, it is critical for industrial applications to understand the physical mechanisms which control this transition during solidification. Many studies highlight the importance of the relative growth of the equiaxed and columnar grains and develop expressions or numerical procedures to describe a criterion for the CET. A number of experimental investigations reported in the literature suggest that the CET occurs when GL in the melt reaches a minimum critical value [5-7]."

Jan 1, 2012

By Babak Mamaqani, Pirooz Barar

Regional Connector Transit Corridor (RCC) is part of the Los Angeles metro expansion project under construction which adds three new stations into the system. PB&A was responsible for the design of the support of excavation (SOE) systems for two stations, 2nd/Broadway and 2nd/Hope, in RCC. In this paper, challenges and lesson learned from SOE design of 2nd/Broadway station with a main focus on underpinning design are discussed. 2nd/Broadway station required to cut and cover excavation of 500 ft long by almost 100 ft deep, underneath 2nd Street. SOE systems consisting of drilled soldier beams with tiebacks and/or struts. The main challenge in 2nd/Broadway station was to underpin the LA Times building which was partially protruded into the station. A chellenging underpinning system consisted of concrete panels and ground anchors was designed to support the building surcharge and prevent settlement. The underpinning system was designed based on METRO design criteria and the deflection was evaluated by Finite Element Analysis (FEA) program, PLAXIS 2D. A maximum deflection of 0.4 inches was calculated to occur at the top of the underpinning system. Data from settlement and tilt sensors showed minimal movements which aligned with PLAXIS outputs. PROJECT DESCRIPTION The Regional Connector Transit Corridor (RCC) is Los Angeles Metro’s ambitious Light Rail Project. It runs under the City’s main thoroughfares, Flower and 2nd Streets, and when complete will alleviate traffic and parking congestion in downtown Los Angeles. The Regional Connector will connect thousands of residents living in the bedroom communities of the Inland Empire and Long Beach to their jobs Downtown. The rail line will serve 1.9 miles, using the $1.756 Billion budget to construct the underground rail line, including 3 new stations, at 2nd & Hope Street, 2nd & Broadway, and 1st St. & Central Ave (Fig. 1).

Jan 1, 2019