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By W. E. Roscoe, K. N. Spence

In the Canadian mining industry, there are at present no comprehensive regulations or standards for valuation of mineral properties. In January 1999, the Mining Standards Task Force of the Toronto Stock Exchange and the Ontario Securities Commission recommended that the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) establish a committee to review and advise on approaches and methodologies for the valuation of mineral properties. The authors were subsequently appointed Co-chairs of the CIM Special Committee on Valuation of Mineral Properties (CIMVal). A committee of experts from the mining industry, consulting, financial and legal communities was established with the task of reviewing available information, investigating various valuation methodologies and practices, soliciting input from interested parties, and recommending a Canadian code or standards plus guidelines for the valuation of mineral properties. As an initial stage of its work, the CIMVal Committee organized a one day session at the Mining Millennium 2000 Convention in Toronto in March 2000 on valuation of mineral properties. The 10 invited papers have been published by CIM. As a second stage, CIMVal has requested input and comments from all interested parties. The next stage will be to prepare a preliminary draft with a recommended code or standards and guidelines. This will be circulated for further input and comments prior to revision and publication of another draft. The final CIMVal report should be completed in early 2001. A variety of methods are in common usage for the valuation of mineral properties, depending on the stage of development of the property, the data available and the experience of the valuator. For example, the discounted cash flow method is commonly used for properties in production or at the feasibility stage, but is not generally considered appropriate for exploration properties. Market approaches such as comparable transactions are in wide general use, and various cost approaches are used for exploration properties. The option pricing approach has promise for valuation of marginal properties, but is not commonly used.

Jan 1, 2001

By Jacob Chacko

The Izmit Bay bridge, a 3-km-long suspension bridge crossing of Izmit Bay, Turkey is planned to be constructed in one of the most seismically active places in the world. The site, which has the potential to experience significant earthquakes associated with the relative motion accommodated on the North Anatolian Fault, is underlain by deep deposits of soft soils, and areas of unstable and liquefiable soils. Characterizing the seismotectonic setting, foundation soil conditions, potential fault locations, as well as other geohazards was a critical component for the project concessionaire to finance the project and obtain meaningful bids for bridge design and construction. Given the Build Operate Transfer (BOT) funding mechanism, executing this work in the least possible time was critical to the concessionaire?s financing scheme. Fugro was retained to provide geotechnical, geological, and seismological evaluations for the project region, and to generate data for contractors to develop reliable designs and bids. The uncertainties in these data made it difficult for the BOT concessionaire to finance the project and tender Bridge design and construction. The investment in an early and comprehensive site characterization program to evaluate and quantify those uncertainties allowed the concessionaire to save schedule, provide a robust bid basis to bridge contractors, and persuade banks to finance what was perceived to be a relatively high risk project.

Jan 1, 2011

The processes by which particles and bubbles interact capture many of the central concepts of colloid science and hydrodynamics. This area of research embraces hydrodynamics, interfacial(including capillary) forces, particle and bubble behaviour and solution chemistry. In this review, we discuss collision, attachment and stability efficiencies. We deal with the identification of a flotation ?domain?, the deformation of a bubble surface upon interaction with a solid surface, the kinetics of three phase contact line expansion and the determination of attachment efficiencies through to the direct measurement of bubble-particle interaction forces. We have recently carried out a test of collision theory where the latter embraces both inertial and centrifugal forces. The real challenge is now to quantitatively describe the behaviour of real systems and to incorporate a reliable description of the behaviour of particles in flotation froths. The approach described is very robust when applied to flotation, both from qualitative and quantitative points of view, providing an intellectual foundation for understanding this complex process in separation science and technology.

Jan 1, 1999

By Chris D. Shewmaker

So you want to install 2,600 augered cast-in-place piles, about 155,000 lineal feet, in 33 working days? It can be done. The Public Service Enterprise Group (PSEG) decided to build a combined cycle power plant in Lawrenceburg, Indiana. PSEG selected Fluor Constructors Indiana, L.P. to design and build the plant. Fluor Constructors, in turn, selected Richard Goettle, Inc. to install the piles. The initial plan was to install the 2,600 piles in 33 days, working six (6) ten hour days per week. After successfully installing and performing four pile load tests - up to 300 ton capacity - we set out to complete the work and meet the aggressive schedule. After three weeks of installing an average of 75 piles a day with three drill rigs, Fluor relaxed the schedule because we were so far ahead of their projected construction sequence. We elected to continue drilling on a ten-hour day, five days a week schedule. In all, we installed nearly 2,800 piles, totaling 175,000 lineal feet, in about 47 days.

Jan 1, 2004

By AIME AIME

MANY producers have held that the only workable quicksilver ore is easily recognized by its .cinnabar content. In most cases this is true. A noticeable exception is a. particular opalite deposit where part of the ore now being mined in considerable quantity shows only the yellow mineral, calomel, or its alteration products. This mineral, on exposure to the sunlight, quickly becomes coated with gray or black layers that may be removed by scraping to reveal the yellow mineral beneath. The blackening of this mercuric chloride on exposure to sunlight shows reaction to form metallic mercury, which is usually plainly present in this class of ore.

Jan 1, 1929

By C. S. Brooks

Several of the commonly used methods for deter-mination of effective grain densities of minerals have been evaluated for accuracy and precision, and their applicability to various types of petroleum reservoir minerals tested. Consideration was given to the effect of consolidation, swelling clay, and wettability on these grain-density determinations. Procedures with helium displacement, a modified low-pressure Boyle's law porosimeter, and liquid displacement (water, n-decane, and n-octanol) were tested. The helium-displacement procedure was used primarily as an independent reference for which the effects of fluid-solid interaction, e.g., adsorption and wettability, were negligible. The procedures with the Boyle's law porosimeter and with liquid displacement are the methods in common use. Minerals investigated included calcite, West Texas limestone core samples, California sandstone core samples, and Wyoming bentonite. The number of samples tested, while not large, was adequate to permit application of statistical methods. Grain-density measurements on calcite (Iceland spar) provided a basis of comparison for the accuracy and precision of the procedures under investigation for a material with a high degree of chemical and physical homogeneity and for which fluid-solid interactions were at a minimum. Liquid-displacement procedures (water or n-decane) provided the greatest reliability and precision for measurement of the grain densities of the limestone tested. Gas-displacement procedures (helium or Boyle's law porosimeter) provided the greatest reliability and experimental convenience, if not the greatest precision, for the measurement of the grain densities of the swell- ing clay, Wyoming bentonite, and the shah sandstones which -contained appreciable amounts of swelling, in-terstitial clays. These experiments were designed to evaluate the applicability of the grain-density procedures in common we to some of the less tractable minerals—tight limestones, shaly sandstones, and swelling clays. The results should provide a useful basis for a selection of the method most suitable for application to the various petroleum reservoir minerals encountered and especially for use in the estimation of formation porosity. INTRODUCTION These experiments were undertaken to evaluate the accuracy and precision of several commonly used methods for determination of effective grain densities of minerals, and to test their applicability to various types of petroleum reservoir minerals. Consideration was also given to the effect of consolidation, clay, and wettability on these grain-density determinations. Procedures used included measurements with helium displacement, with a modified low-pressure Boyle's law porosimeter, and with liquid displacement (water, n-decane, and n-octanol). The minerals investigated included calcite, West Texas limestone core samples, California sandstone core samples, and Wyoming bentonite. The accurate determination of the porosity of petroleum reservoir formations, in particular those of low porosity, has received much attention. Both bulk-volume and grain-volume measurements necessary in the evaluation of porosity have been examined by many investigators with the objectives of improving both the accuracy and the precision of these determinations. In this investigation statistical criteria for selection of the most reliable and suitable procedure for use with a given type of mineral are demonstrated. The grain-volume measurement procedures appear to be the most susceptible to improvement.

Jan 1, 1958

By K P. Crameri

The Beta Hunt orebody is situated on the south western limb of the Kambalda dome. It is one of the nickel occurrences in the area which fall into the category of æKambalda Style OrebodiesÆ. These orebodies are renowned as being continuous uniformly mineralised ribbons of nickel sulfide mineralisation. Interestingly, Beta Hunt does not conform to this notion of continuity and uniformity and is in fact highly irregular in its ore distribution due largely to the influence of post depositional structure. In an attempt to understand the ore distribution at delineation stage rather than development stage a detailed footwall topography model is created using all available drilling data. To augment this drilling data, the routine use of downhole EM and borehole radar has been introduced to provide data beyond the confines of the drill core to enhance the geological interpretation of the footwall topography and the distribution of the mineralisation. The implementation of a detailed footwall model and the use of downhole geophysics has proved to be very effective in resolving the orebody complexity issues. Ongoing development of the methods used will continue to refine the interpretation of the geology to enable more efficient extraction of the orebody.

Jan 1, 2006

By Mel Febesh

Working in New York City has become the graveyard of many Foundation Contractors. Varying subsurface conditions require Foundation Contractors to be aware of the conditions at each particular site and have the knowledge and equipment to successfully complete the project. Looking back, we can see that many of the methods and much of the equipment that were commonly used in the past have been replaced with newer methods and equipment, but sometimes the old methods prove to be the most reliable. This paper will describe examples of varying conditions and construction methods in sites that are close to each other. It will also show different construction problems that are encountered when working adjacent to existing subway structures, when excavating below the foundations of adjacent structures and when ground water is encountered.

Jan 1, 2000

By J. Yianatos

The regrinding stage is necessary to achieve the particle size (liberation) for the final upgrade in the cleaning flotation process. At present, vertical mills (Vertimill) are employed at industrial scale, using small steel balls as grinding media. The regrinding process characterization requires mixing regime knowledge along with the mean residence time of the liquid and solid phases. The residence time distribution (RTD) and the actual mean residence time estimations from theoretical relationships are complex due to the presence of three components (solid mineral, balls and water), mass transport characteristics and segregation affecting solid holdup. Therefore, the experimental RTD determination is suitable for industrial mills. In this work, RTD measurements were performed in two different industrial flotation plants. Both plants operate with Vertimills of 1000-1500 HP in the regrinding process with different circuit arrangements according to the plant treatment capacity. The RTD was measured using the radioactive tracer technique. This technique allows for non-invasive tracer detection where the procedure consists of selecting a liquid (Br82 in aqueous solution) or solid (irradiated solid) tracer for RTD data acquisition in real time. The RTD was modelled by the Large and Small Tanks in Series (LSTS) model, which allowed the characterization of the different mixing regimes for both liquid and solids in the regrinding mills. Effective mean residence times in the range 2-11 min were obtained with RTD shapes similar to those obtained in tumbling ball mills. It was found that residence times of liquid and fine particles were similar, which is consistent with results observed in other mixing systems, e.g. mechanical flotation cells. Also, the mean residence times estimated from the RTD allowed the mass balance adjustment to be validated from metallurgical sampling data. RTD estimations are useful for better understanding the Vertimill behaviour and to identify the actual breakage rates. Keywords: vertical mill, residence time distribution, particle size, modeling

Sep 1, 2012

By R. V. Higgins

"INTRODUCTION When nations throughout the world are pitted against each other in a war in which petroleum plays a major role, scientist and engineers of the petroleum industry must give serious thought to ways and means for recover¬ing greater percentages of oil from natural reservoirs than in the past. Petroleum and its products are vital to highly mechanized modern warfare, and the victorious nations will be those whose armies, navies, and air forces are supplied with adequate fuel oil, gasoline, and lubricants until the war is won.Efficient recovery of oil from underground reservoirs depends on many interrelated techniques; evaluation of the producing performance of wells upon the basis of their productivity indexes is one such tool. Oil wells usually yield oil at a maximum rate when first ""brought in"". The rate of production begins to decline soon after the first oil is delivered to the tanks, and although part of the decline usually can be attributed to natural reduction of reservoir pressure as oil and as are withdrawn from the reservoir, a larger proportion frequently is caused by greater saturation of water and as in the producing formation about wells and clogging of the pores of the sands by silt, organic salt, and insoluble hydrocarbons. If the maximum quantity of oil is to be recovered from reservoir sands and rocks by wells, it is then imperative that the ability of wells to produce oil be watched closely and all adverse influences that affect the case with which oil can flow to wells be corrected if possible."

Sep 1, 1942

By W. Zitz

Incorporation of heat exchangers into drilled shaft foundations is a novel approach to both improve the energy efficiency of building heat pump systems and provide necessary structural support using the same construction materials. In an effort to quantify the structural and heat exchange performance of deep foundations used as ground-source heat pumps, two instrumented test foundations were constructed as part of a new construction project in Denver, CO. They will be integrated into the conventional ground-source heat pump system for the building. This paper focuses on the lessons learned from the construction process for these energy foundations.

Jan 1, 2011

Throughout 1992 Pasminco conducted field trials of the Mobile Miner MM130 at Broken Hill. The goal was to develop the machine to achieve acceptable reliability and establish production rates.

Jan 1, 1993

By R. D. Currie

Many coal companies have a system for checking men into and out of the mine , and generally such systems appear to be perfectly sound and adequate . However , when the real test comes at the time of a mine disaster , too often the system is found to have failed , and hours and sometimes days pass before it is known how many men are in the mine and who they are . Most of the systems in use , when properly maintained , are adequate for the routine work of the mine , and some of them may prove adequate at the time of a mine disaster . All systems , however , depend upon proper supervision and strict adherence to the system .

Jun 1, 1930

By R-H Yoon

Increasing the upper particle size limit of flotation would allow operators to increase mill throughput, save operating costs, simplify flow sheets, and increase rate of return. However, coarse particle flotation is difficult for various reasons, of which bubble-particle detachment has been identified as the major limiting factor. In the present work, the process of bubble-particle detachment has been studied by directly measuring the forces required to detach air bubbles from hydrophobic solids. The measurements were conducted using a hanging balance apparatus. The measured forces were converted to detachment energies that can be compared with the work of adhesion, which in turn is a function of hydrophobicity, surface tension and contact area. The results were converted to detachment energies using the Young-Laplace equation for capillarity. In the present work, the solid surfaces were hydrophobised by coating them with octadecyltrichlorosilane and cetyltrimethylammonium bromide. The results show that bubble-particle detachment occurs in two steps. In the first step, air bubbles are deformed, while the three-phase contact (TPC) line is pinned, until contact angle reaches advancing angle. In the second step, the TPC line moves along the surface until solid/air interface is replaced by solid-liquid interface. In general, the energies of detachment measured in the second step are in good agreement with calculated work of adhesion. Thus, the energy required during the first step effectively represents an energy barrier for bubble-particle detachment. It has been found that the energy barrier varies with surface roughness and surface tension. The results of the present investigation suggest, therefore, that coarse particle flotation can be improved by control of particle hydrophobicity, surface roughness, and surface tension.

Jan 1, 2005

By Roman Z. Pyrih

Subsurface migration of cyanide is attenuated by naturally occurring geochemical and biogeochemical processes. Geochemical mechanisms which remove or immobilize cyanide and metal-cyanide complexes include precipitation/coprecipitation, sorption, and volatilization. Geochemical properties of soils and geochemical materials that promote the functioning of these mechanisms include the following: 1) acidic soil pH; 2) presence of illite and smectite clays; and 3) presence of iron hydrous-oxides and organic carbon. Naturally occurring soil microorganisms play perhaps a more important role in attenuating cyanide movement than previously realized. Biodegradation of cyanide is a "renewable" process, limited in its effectiveness by the avalibility of oxygen and micronutrlents (usually phosphate) to the microorganisms.

Jan 1, 1990

By Martin Epner, Eric Gregory

DURING the past decade, considerable work has been carried out on various cermet systems in an effort to produce materials suitable for high-temperature applications in gas turbines. Most of the materials have not, as yet, met the requirements of the engine manufacturers, primarily because of their lack of room-temperature ductility and thermal shock resistance. In the field of tool materials, however, although ductility is still of prime importance, much has been accomplished by improving design parameters and the quality of carbide materials with a view to using cermet compositions successfully. The systems described in this paper were designed primarily for application in this field, although their development was a natural outcome of work on similar compositions designed for high-temperature service. In steel-bonded titanium carbide, the steel binder imparts heat treatability to the system while the carbide provides abrasion and wear resistance. Combining the carbide and the steel matrix in carefully controlled proportions results in a composite material which, when the steel is hardened, has man of the properties of cemented tungsten carbide. In the annealed condition, this material can be readily machined by the conventional chip-removal techniques. Titanium carbide has certain distinct advantages over many of the other carbides when combined with a steel matrix. It is among the hardest of the carbides and is one of the most stable. Liquid iron wets titanium carbide, and this wetting assists in the formation of a dense cermet. Once the composite structure has been formed, the titanium carbide acts as a relatively inert phase during the heat treatment of the matrix. PREPARATION OF ALLOYS The steel-bonded titanium-carbide materials described in this paper were prepared by the liquid-phase sintering technique. The titanium carbide used had an average particle size of 6 to 7 p, a total carbon content of 19.4 pct and 0.35 pct free carbon. This was blended with the elemental metal powders by ball milling them together in a hexane medium. After drying, paraffin wax was added to the blend to provide green strength in the pressed briquettes, and compacting was performed at 15 tsi. Liquid-phase sintering was carried out in vacuum at temperatures which depended on the chemical composition of the system involved, but which were usually around 2640° F. The resultant materials had a density approaching 100 pct of theoretical. The

Jan 1, 1961

By R. Pérez, James A. Finch, F. Tavera, Cesar O. Gomez

"Gas holdup is a variable which affects the operation of flotation columns. On one hand, gas holdup is a function of bubble size (a function of sparger type, frother characteristics and concentration, and air flowrate), tailings flowrate, solids content, and mixing patterns in the collection zone. On the other, gas holdup defines flotation kinetics and carrying capacity. Therefore, gas holdup is a useful variable to control and diagnose the operation of a flotation column, but the lack of a reliable sensor for on-line gas holdup monitoring has prevented its use in industry.This work describes the principle and the practical difficulties associated with the development of a gas holdup sensor based on the measurement of the electrical conductivity of dispersions. Two different approaches have been devised. These approaches will be described and test results presented of prototypes in laboratory and industrial columns.Background.Several years ago, a research program was initiated at McGill to use electrical conductivity as the basis for developing sensors for process measurements in mineral processing. Electrical conductivity is an intensive property which is a function of the concentration of the different phases present in a dispersion. The initial focus was on the detection of the interface between two dispersions with different characteristics (i.e., that between the collection and froth zones in flotation columns or that between clear water and sedimented solids in thickeners). The technique works in this case by searching for the location at which a sudden change in specific conductivity occurs, as a consequence of different gas holdup or solids content, and absolute values of the specific conductivity of the dispersions involved are not necessary1,2."

Jan 1, 1995

By Roberto Maldonado Astorga

El presente texto señala la implementación del modelo de gestión para las operaciones de Volcán Campaña Minera, basado en el Modelo de Gestión de Malcom Baldrige. El modelo tiene el objetivo de establecer un proceso sistemático y estandarizado que asegure la mejora contínua y en línea con la visión de la empresa que apunta al logro de la excelencia operativa. La estrategia se divide en tres módulos: Módulo de Organización, Módulo de Gestión y Módulo de Comunicación. Asimismo se busca, implementar círculos de optimización permanente, monitorear de forma sistemática la ejecución de iniciativas de mejora y seguir el impacto en los indicadores.

Nov 1, 2014

By F. D. Rodriguez, J. Ramirez Cuellar, J. Salinas Reyes, C. Gómez-de-la Garza

The Pickling Line and Tandem Continuous Mill (PLTCM) at Ternium Pesquería Facility with a Five Stands, Six High configuration started in 2013. Manufactured by PRIMETALS, to produce steel to exposed automotive market, Turnkey project, with supervision of best practices from Nippon Steel. The main equipment that the process has are; Laser welding machine, 3 loopers, Scale Breaker, jet Pickling tanks, Inspection Station and COGNEX System Side Trimmer (flying width change), Type of Mill: UCMW(S) Carrousel, 2 Tension Reels. The principals goals are, Simulate production programs, validate materials for thin thicknesses before processing, low Re-welds, optimization use Cognex, good performance in Thickness, flatness and productivity.

Oct 1, 2019

By Persifor Frazer

(Read at the Amenia Meeting, October, 1877.) IT has been the aim of the writer, by measuring his base line on the territory of theoretical chemistry, to attempt to fix by triangulation certain points within the domain of mineralogy. As the barest first experiment in this direction, a few of the hydrated oxides of iron have been selected, their theoretical construction reduced to percentage of the constituents into which the ordinary analytical methods would resolve them, and the results compared with actual analyses compiled from the most reliable sources; the accidental errors being as much as possible eliminated. This method seems to be a simple one and one easily pursued, but, as will shortly appear, it is beset with grave difficulties, all of which the writer does not pretend to have satisfactorily surmounted. In the first place arises the important question, what are we to understand by the hydrated oxides of iron ? In all books of chemistry and lexicons of minerals, the proposition, long ago taught by the earlier chemists, that water might exist in two forms of combination, viz., as water of crystallization or as water of constitution, is tacitly assumed. There is nothing in the principles of the new chemistry which is opposed to this ; for (to carry the mind's eye into .the process of construction of the least units into which a definite chemical compound is capable of being divided without losing its characteristic properties), however unlikely it may seem, it is, nevertheless, possible that a given molecule of iron may, under certain conditions of heat, pressure, etc., attract to itself as many molecules of the water in which it is natant as from the relative size, shape, attractive force, etc. of either, it is capable of taking up, and this complex system of associated molecules might oscillate as a physical unit so long as the conditions on which its existence was dependent remained unchanged. Moreover, it is highly probable that the first effect upon such a molecule produced by physical or chemical forces would be to separate it into two or more simple ones of different kinds, while a further application of these forces might rend asunder the bonds of the simpler compounds themselves.

Jan 1, 1878