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By R. H. Nafziger

The Bureau of Mines evaluated 18 domestic titaniferous materials with widely varying compositions, mineralogy, and physical properties in electric-arc furnaces, Techniques were devised to recover both the titanium and iron values contained in these materials so that the reliance of the United States on foreign sources of higher grade ilmenites and rutile might be decreased. Most of the tested titaniferous materials responded well to lower grade or byproduct reductants, such as bituminous coals, charcoal, and coke breeze. Sufficient slag fluidity was realized by maintaining from 8 to 12 wt-pct iron in the slags; no contaminating fluidizers were required. Fluid slags containing up to 79, 70, and 54 wt-pct Ti02 were realized from east coast ilmenites, a rock ilmenite, and a titaniferous magnetite ore, respectively. A carbon-lined furnace shell is recommended for minimum slag contamination. Good results also were obtained during extended submerged-arc furnace tests.

Jan 1, 1980

By Takao Oishi, Go Ohara, Toru Kitazaki, Masahiro Tanaka

"The High Pressure Acid Leach (HPAL) plant for nickel-cobalt mixed sulphide production at Coral Bay Nickel Corporation (CBNC) in the Philippines has been in operation since 2005 with a capacity of 10,000 t/year of nickel. Subsequent to the commissioning of the second plant in 2008, the production capacity increased to 22,000 t/year of nickel (Llerin et al., 2011). CBNC’s annual nickel production reached more than 24,000 tons of nickel in 2014. The concepts to achieve this capacity are the high availability and the reciprocally flexible operation of both plants. The availability depends on some factors, such as the control of impurities in the process and the equipment condition, to mention a few. In the HPAL process, it is not only the autoclave operating conditions that affect nickel extraction but also the impurities in the ore greatly influence it. The major element in the ore is iron and most of this iron is precipitated as Fe2O3, while the rest remains as Fe2+ or Fe3+ sulphate in solution. These ions in solution reduce the availability, so it is important to control the formation of iron ions by controlling the impurities in feed ore as well as the HPAL conditions. This paper presents the general HPAL process and the behaviour of impurities, focusing on iron behaviour in the HPAL process.INTRODUCTIONCoral Bay Nickel Corporation ProfileCoral Bay Nickel Corporation (CBNC) was founded on April 2002, as a joint venture of four companies; namely, Mitsui Corporation (18%), Sojitz Corporation (18%), Nickel Asia Corporation (10%) and Sumitomo Metal Mining Corporation (SMM) with a controlling stake of 54%. Aside from its capital share, Nickel Asia Corporation also supplies the ore and limestone for the High Pressure Acid Leach (HPAL) plant located in Rio Tuba, Philippines, as shown in Figure 1 (Tsuchida, 2008). The objective of the CBNC project is to produce 22,000 t/year (original design) of nickel and 1,500 t/year of cobalt, as sulphide, by the treatment of nickel laterite ore which is a low grade nickel oxide ore in the Philippines (Mines and Geosciences Bureau, 2014). The sulphide product has been exported as a raw material to the SMM Nickel Refinery in Japan for 30 years. The product of this plant, a mixed (Ni/Co) sulphide, is shipped to the SMM’s Nickel Refinery in Niihama, Japan. SMM Corporation provides the technology and management personnel to the plant. SMM Corporation also supplies the sulphuric acid, which is the main reagent for the HPAL process."

Jan 1, 2016

By H. Attia, S. Engin

This paper presents a practical approach for determining the optimal spindle speed and the depth of cut in a milling operation within the ever-increasing economic and technical constrains. Analytical modeling and experimental work has been carried out to predict chatter in such operations. The stability lobes determined from this analysis were then used as a constraint in the optimization of the cutting process. The optimal cutting conditions are determined for two different objectives: maximum metal removal rate and minimum cost per unit. It is demonstrated that this approach can be generalized to impose multi-level constrains, e.g., surface integrity and machining accuracy. The approach presented in this work was examined and validated on three NC milling machines. The productivity improvement, cost reduction, while respecting part quality requirements, is demonstrated.

Jan 1, 2006

By C. L. Lin

Transformation of linear grade distribution to volumetric grade distribution has been used to estimate the actual mineral liberation during wet, batch, ball mill grinding of a copper ore. The degree of liberation based on the multicomponent-multisize grinding liberation model using volumetric grade is lower than the apparent degree of liberation estimated from using King's linear intercept model.

Jan 1, 1987

By P. Harris, N. Heywood

An existing 1 800 m long pipeline, which carried waste mica slurry from kaolin processing, is to be recommissioned. The mica solids throughput is to be substantially increased from 5.2 t/h up to a maximum of9.53 t/h, but with a typical throughput of around 7.5 t/h. Because of this throughput increase, it was unclear whether the existing 80 mm diameter pipe would be adequate. In addition, the pipe route is to be extended by 250 m to 2 050m, and its elevation at discharge to settling lagoons increased from 66.2 m to 80 m. The pipeline hydraulics of waste mica slurry were investigated for the 80 mm diameter pipe using the Saskatchewan Research Council?s (SRC) Two-Layer Flow Model, for the maximum mica solids throughput of 9.53t/h. The pipe operating velocity was compared with the predicted deposit velocity for several mica concentrations, ranging from 20% to 50% by weight. Estimates were made of the total differential pressure across the proposed2 050 m long pipeline, as well as the power imparted to the slurry by the pump, and the specific energy consumption (SEC). Two pipe diameters were assumed: 80 mm when no mica wall deposit is present, and 70 mm when there is a 5mm mica wall deposit. This parameter has a significant effect on the determination of the appropriate pipe operating conditions. For the pipe operating velocity to remain adequately above the deposit velocity (and therefore for the heterogeneous flow pattern to prevail in either horizontal or inclined pipe), it was concluded that if the newly commissioned pipeline contains no mica wall deposit, the pipe should initially be operated at a mica concentration of between 20% and 25% by weight, probably with a target mica concentration of about 23%. A 23% mica

Jan 1, 2007

By Walter Fuchs

It is now generally conceded that coal is the product of deposition and transformation of debris of forests and swamps.29 Ample data are available to illustrate the metamorphosis of biochemical substances through biological action; other data show the progressive regional metamorphism existing in coal beds;25 and numerous examples of change effected by intrusion of igneous dikes into coal deposits have been established.23 However, often the relative importance of the biological and the geological factor in determining the character of the various natural coals is a debatable question. Since both biological and geological factors are ever present in nature, the problem, at first glance, would appear to resemble certain probability problems: specifically the simultaneous toss of two coins, with the biological factor as heads and the geological as tails. The probability is 2:I for the combined effect of both factors, as compared to the exclusive effect of either one, if the a priori probability is the same for each factor. This condition can be analyzed by a thermodynamic treatment of data, which may be obtained from a consideration of pertinent biological, chemical, geophysical and geological facts. Synopsis of Biological and Chemical Facts The biosphere is not sterile; i.e., microorganisms are always present. Microor- ganisms have been established in the ocean deep, under the ice of the polar regions, in the sand of the deserts, and in swamps far below the surface. The various biological media may be acid, neutral, or alkaline, and they may or may not be readily accessible to air. Microorganisms are encountered almost everywhere, except where the temperature is not within the range tolerable by microbial life. Of course, with changing conditions, the type of microorganisms will change. All chemical products of life—proteins, fats, carbohydrates, lignins, waxes, resins— may serve as a habitat of microorganisms. In the decomposition of a medium, some microorganisms macerate organic matter mechanically and remove certain constituents for their own nutrition; others decompose a large part of the organic matter but may leave certain constituents undecomposed. Some attack only certain specific ingredients of the organic matter. All of them build up cell substance. The nitrogen content of the medium largely determines the degree of decomposition. Below 1.7 per cent nitrogen, growth of microorganisms and hence decomposition of organic material is retarded; consequently organic material will accumulate.17,32 Such accumulations of organic material may give coal eventually. Coals differ in type and rank. The nature of the original vegetation and the conditions attending the transformation of the accumulated debris determine the type of coal such as bright, splint, cannel, and algal or boghead coals. Chemical analysis of representative samples of a given type of

Jan 1, 1942

By H. William Ahrenholz

Many technical meetings were attended by mining people during the past year in which rock mechanics was either the main subject for discussion or was a prominent part of the program. Several universities continued to offer short courses in the applications of rock mechanics for practicing mining engineers. At the beginning of the year, the AIME Committee on Rock Mechanics achieved standing-committee status. It is to assume responsibility for coordinating all AIME activities in this area. Eleven professional societies are now participating in a newly formed Intersociety Committee for Rock Mechanics. AIME and its constituent societies has three representatives. Delegates from the Intersociety Committee will serve on the U.S. National Committee for Rock Mechanics which is being formed by the national Academy of Sciences.

Jan 2, 1967

By Littlewood E

We offer these notes as a practical contribution. All the arguments we advance have been tested by practical experience.In its preparation we realised that our subject was one of such importance and covered so wide a field that, dealt with by one of us alone, it might easily have been too much for him, so we have endeavoured, by mutual criticism and advice and a pooling of ideas, to bring forward a few points that may be of advantage to members. If any of the paper is of benefit to mining on the "Golden Mile," or elsewhere, we shall feel amply repaid for our efforts.It is obvious to all that the longer the machine is working productively per shift the greater the return, to all concerned; the machine-man himself and the company. Furthermore, if a man commences a shift with a definite objective in view; for instance, to bore and fire a specific cut, which he recognizes will give him a good financial return, then that man will exercise all his capabilities to attain that objective.In this paper we hope to demonstrate the value to the machine-man of the knowledge of the capabilities of each hole he bores, so that he will be enabled to utilize his drilling time to the greatest advantage. Also, we hope to show that such drilling time can be advantageously extended.After the war, with the influx of new men to the industry, some education on the finer points of machine work may be desirable, and any instruction in this branch must stress the realization of the value of each hole.We realise that most of those present have a sound workable knowledge of machine-mining, and we are not trying to teach anyone the fundamentals of machine work, but we would like to bring to their attentIon some of the finer points which we believe are very important.The machine-man has control of gear of a capital value of over £150, and the use or misuse of that material has a direct bearing on working costs. Therefore it is imperative that the capital outlay is gainfully employed.A "bogger" in charge of a 5/- shovel engaged unproductively is bad enough. How much worse for £150 worth of gear to be not fully productive.Figs. 1 and 2 demonstrate angles of break, and the full realization of the importance of this angle is essential to our paper. Although these Sketches are two-dimensional, we hope they will be sufficient to demonstrate our meaning. We will pass over them as briefly as possible.Fig. 1 shows three holes asked to perform an identical task.(a) 7-ft. hole bored 2 ft. into solid ground-will not come out.(b) 4-ft. hole bored 1 ft. from solid ground-will come out easily.(c) 5-ft. hole bored to solid ground-the best that can be expected under general conditions encountered.The angle of break is a right-angle, normal to direction of hole.

Jan 1, 1944

By E. G. Beinlich

The continuing search for faster, safer, and more economical methods of excavating underground openings has led the staff of the Mather mine of the Negaunee Mine Co. directly to mechanical boring of raises and drifts. The mine is located within the city limits of Negaunee and Ishperning in the eastern portion of the Marquette Iron Range in the Upper Peninsula of Michigan. It is owned jointly by McLouth Steel Corp., Bethlehem Steel Corp., Republic Steel Corp., and The Cleveland-Cliffs Iron Co., who also serves as the operating agent. A total of 2,400,000 tons of iron ore averaging over 60% Fe is mined annually by the block-caving method. This provides feed for the Pioneer pellet plant at Eagle Mills where 1,450,000 tons of pellets are produced yearly with the remaining tonnage being sold as coarse ore. Technical staff of Cleveland-Cliffs have long realized that improved methods of advancing raises and drifts were a necessity if underground mining of iron ore was to survive the transition period in the steel industry's requirements from direct-shipping ore to pelletized ores. For this reason, the Mather mine embarked upon an experimental raise-boring program with a prototype machine in 1961. Improvements since that time in equipment and practice have resulted in the acceptance of mechanical boring of raises as a standard development tool and a vital link in the fulfillment of an orderly development schedule. Advancement of large-diameter openings such as main-level drift headings by mechanical methods in the harder, more competent types of rock has developed more slowly in the mining industry due to the need for more compact and portable machinery and improved bit technology. Many of the obstacles have been overcome by the manufacturers, and in March 1967 it was decided to proceed with a program to bore approximately 4000 ft of 13-ft-diam drift in the Mather graywacke footwall rock.

Jan 1, 1970

By Y. Miron

Previous studies at the Bureau of Mines outlined the hazards of ammonium nitrate-fuel oil (AN-FO) mixtures in the presence of pyrite-bearing ores. The recent trend in the mining industry to strengthen AN-FO by the addition of aluminum metal raised the question regarding the effect of aluminum in AN-FO in the presence of pyrite-bearing ore. Laboratory work, similar to that done previously, demonstrated that the temperature of a self-sustaining reaction in the presence of AN-FO ore-aluminum is not lower than that for a comparable AN-FO-ore mixture. However, as might be expected from known thermochemical data, once initiated, the resulting reactions between AN-FO, aluminum, and pyrite are much more vigorous than those observed for AN-FO and pyrites alone. The temperature required to produce a self-sustained reaction for the combinations tested in this study is 250°±20° F while in the previous Bureau study, reactions were noted, in some instances, at 150° F. The different pyritic ores may be the cause of this variation.

Jan 1, 1976

By A. Y. Senchenko, Y. V. Kulikov

"The most common technique for selection of grinding equipment is the Bond method implying determination of a ball mill work index (BWi). The method is perfect for greenfield projects where a ball mill must be sized to grind an ore to 80% passing 75-100 µm. Finer grinding will require application of specific correction factors to a standard equation since initially the method was not designated for sizing of fine (minus 75 µm) grinding mills. Significant issues are related to selection of grinding equipment for treatment of originally fine materials when the standard procedure is not applicable. In 1984, Levin published his special technique titled as “A proposed test for the determination of the grindability of fine materials”, where he offered to use the standard Bond ball mill for determination of a specific grinding energy. However, this method did not meet with wide recognition. In 2017, Institute TOMS under guidance of JKMRC’s specialists performed a testwork aimed at verification of a new universal technique for determination of grindability of initially fine materials. An object was to test three aged tailings samples for the subsequent modelling of comminution circuit and evaluation of potential throughput of the existing ball mills with final grind size of ?80 passing 53 µm. In parallel with development of the universal approach, TOMS’ specialists carried out tests according to the Levin method in order to compare the data resulted from two methods. The results from lab ball mill testing on three products following the alternative test methods are presented in this paper along with the testing methodology and results analysis. Specific energy was calculated for regrinding of the materials to the required size. Difference of the examined methods and assessment of their applicability for sizing of full-scale equipment are explored."

Jan 1, 2018

By Harry Roe

THE power drag scrapers and the slackline cableway excavator have been called "long-range excavators." Broadly, their field of usefulness is restricted to work in which their long range of action permits them to operate economically, and which other, possibly more conventional, excavating units cannot do. Both of these machines dig or lift material and transport it to a clumping point. They combine these two functions in a single machine, nearly always in a single straight-line motion. FIG. I.-SIMPLE FORM OF POWER DRAG SCRAPER. The purpose of this paper is to examine the important features that distinguish the machines in this group from each other, as well as from other groups.

Jan 1, 1937

By A. Raman, P. P. Singh

The constitution of the La-Rh system was studied by powder X-ray diffraction, metallopaphic, and differential thermal analysis techniques and an equilibrium diagram is presented. Eleven intermediate phases occur in the system and the crystal structural data for nine of them were determined. La3Rh crystallizes in an orthorhombic structure of undetermined type, whose unit cell is obtained by doubling the 'a; and 'c,,' edges of an FesC type unit cell. The other intermediate phases of the system are LarRh-3( undetermined structures also occur in the system. LaRh, undergoes a polymorphic phase transformation at 1240°C. LaRh3 and La2Rh7 also exhibit polymorphisnz. The phases Laah and LazRh7 melt congruently. The latter undergoes a eutectoid transformation into LaRh, and Rh at 1205°C. Laah3 is formed by a peritectoid reaction between Laah and La,Rh,,. The other Phases result from peritectic reactions between the liquid and the adjacent rhodium-rich phases. The intermediate Phases of the La-Rh system are compared with those of the La-Co and La-Ni systems. DURING the course of a detailed investigation to study the occurrence of CrB, FeB, A1B2, and related structures in the rare earth alloys it was found that much information is lacking for the rare earth noble metal systems. Although the structures of several rare earth alloys containing the noble metals at the AB and AB2 stoichiometries have been reported, the occurrence of related structures at other stoichiometries has not been studied. We have initiated a project to study the crystal structural features of selected rare earth-rhodium alloys and to map the equilibrium diagrams of representative systems with conventional methods. The results of our investigation in the La-Rh system are presented in this paper. Two phases were known in the La-Rh system. LaRh has the CrB-type structure.' LaRhz is a MgCu2-type Laves phase.z EXPERIMENTAL PROCEDURE Alloys weighing less than 1 g were prepared from commercially pure lanthanum (99.9 pct +), supplied by Lunex Company, Pleasant Valley, Iowa, and rhodium (99.92 pct +), supplied by Engelhardt Industries, Newark, N.J., in a conventional arc melting furnace under argon atmosphere. The buttons were turned upside down and remelted three times to insure homogeneity in the samples. Since negligible loss of material was encountered during melting, a chemical analysis of the alloy buttons was not undertaken. Powder specimens for X-ray diffraction studies in the as cast state were then prepared. The buttons were wrapped in thin molybdenum foils and homogenized by heating in vacuum at suitable high temperatures for more than 1 week. They were then broken into three or four pieces for annealing experiments. The pieces were wrapped in molybdenum foils and annealed at various temperatures in evacuated quartz capsules. The annealing was carried out for 2 hr at or above 1200°C, 1 day at temperatures close to llOO°C, 2 days at 1000°C, and for 1 week at temperatures below 1000°C. After annealing the alloy pieces were again broken and powder specimens for X-ray diffraction were prepared. The powders of the lanthanum rich alloys with more than 80 at. pct La were prepared by filing. The filings were sealed in molybdenum tubings and stress-relieved at 600°C in vacuum. It was not deemed necessary to stress-relieve the powders of the other alloys, since the alloys were very brittle and were ground easily. POWDER X-RAY DIFFRACTION X-ray diffraction photographs of powders (-325 mesh size) of the alloys in the as cast and annealed states were prepared in a Guinier-de Wolff focussing camera with copper K, X radiations. These patterns were studied to identify the stoichiometries and the crystal structures of the intermediate phases. The lattice parameters of the phases were calculated after minimizing the differences between the observed sin2 6 values, calculated from the diffraction angles 8, and the sin2 8 values, calculated using approximate lattice constants obtained from a few lines. These differences were minimized manually to less than 0.0005. The latLice constants are judged to be accurate to *0.005A for values less thp about 10A and to k0.01~ for values greater than 10A. The relative intensities of the lines were calculated using a computer program written by Jeitschko and Parthk.~ No attempt was made to refine the atomic positional parameters in the phases. METALLOGRAPHY The phase equilibria in the investigated alloys in the as cast and annealed states were also studied by metallographic examination. The polished specimen surfaces were etched with 10 pct picric acid in alcohol (alloys up to 25 pct Rh), concentrated picric acid (from 25 to 37.5 pct Rh), 2 pct nital (40 to 50 pct Rh), 10 pct nital (from 50 to 66.7 pct Rh) and with concentrated 48 pct HF for the other rhodium-rich alloys. Selected microstruture~ were then photographed using a Po-laroid Land camera. THERMAL ANALYSIS Differential thermal analysis of the alloys was carried out in DTA-668 Stone differential thermal ana-

Jan 1, 1970

By R. G. Swanton

The Bureau of Mines is investigating the leaching of phosphate values from Florida phosphatic clay wastes using sulfuric acid (H2SO4) as the leaching agent and methanol as the solvent. Acid-alcohol leaching studies were done using pure crystalline apatite to investigate potential causes for low extractions. It was found that a barrier layer formed on the surface of the apatite. Initial discovery of the barrier layer was made by analyzing pure apatite samples before and after leaching using an optical microscope. Subsequent Fourier Transform Infrared (FT-IR) analyses proved the coating was calcium sulfate hemihydrate (CaSO4-1/2H2O) and that unreacted apatite existed beneath the coating. Scanning electron microscope (SEM) photographs depict the CaSO4-1/2H2O morphology as long slender crystals adhering to the apatite surface. It was also shown that grinding the leached tailings and leaching again in the H2SO4-methanol system resulted in additional phosphate extraction.

Jan 1, 1991

The following comment has been received from Mr A. D. Osche* on the above paper, which was published in the Journal in October 1977 (vol. 78, no. 3, pp. 51-62). Obituary: T. K. Prentice The Institute records with deep regret the death on 30th January of its senior surviving Past President, Mr Thomas Kennedy Prentice, at the age of 83. Book reviews R. A. Rich, H. D. Holland, and U. Petersen. Hydrothermal uranium deposits. (Developments in Economic Geology, vol. 6). Amsterdam, Elsevier Scientific Publishing Co., 264 pp. with 77 illustrations and diagrams, 30 tables. U.S. $34,75. M. David. Geostatistical ore reserve estimation. Amsterdam, Elsevier Publishing Company, 1977. 364 pp. World mineral industry The Australasian Institute of Mining and Metallurgy is celebrating its sesquicentenary in 1979. A conference will be held in Perth from 13th to 18th August, 1979, as part of the celebrations, the theme being 'Australia's Role in the World Mineral Industry'. Engineering teaching staff UNESCO has extended its technical assistance to the Venezuelan government in the training of engineers to suit the rapidly developing economy of the country. UNESCO vacancy Vacancy for a post of expert under the UNDP. (1) Title of post: Expert in metallurgical engineering. (2) Duty station: Instituto Universitario Politecnico of Ciudad Guyana (Venezuela). Shell Design Awards The annual Shell Design Awards, organized by the Design Institute and sponsored by Shell South Africa (Pty) Ltd, focus attention on achievements in South African design.

Jan 1, 1978

By David L. Veith

Caustic scrubbing followed by silica flotation with cationic ether primary amine proved effective in upgrading commercial magnetic concentrates to supergrade products containing 2 percent SiO2, or less. Samples representing 41 million long tons per year of commercial magnetic concentrates from the Lake Superior region were tested by the Bureau of Mines. Bench-scale and pilot plant research indicated an estimated potential of 32 million long tons per year of superconcentrates to be available. Two pilot plant investigations yielded superconcentrates containing 1.1 and 1.9 percent SiO2 that were derived from commercial concentrates containing 7.0 and 4.2 percent SiO2, respectively. Corresponding iron recoveries were 90 and 93 percent at reagent costs of just over 33 cents per long ton of superconcentrates produced. Additional sources evaluated on a bench scale resulted in iron recoveries of 72 to 95 percent in products containing 1.7 to 2.0 percent Si02. Although reagent cost ranged up to 60 cents per long ton of superconcentrate, it is probable that these costs would be reduced in plant applications where benefits are derived from material and reagent recycle.

Jan 1, 1974

By Lawrence Devon Smith, Keith Spence, William Roscoe

"In March 2003 the CIM Council adopted and approved the document “Standards and Guidelines for Valuation of Mineral Properties” as developed by the Special Committee of the Canadian Institute of Mining, Metallurgy and Petroleum on Valuation of Mineral Properties (CIMVal). The document is referred to as the CIMVal Standards and Guidelines. The document evolved from a specific recommendation by The Mining Standards Task Force (MSTF) of the Toronto Stock Exchange and the Ontario Securities Commission in its Final Report (January 1999) that the CIM form a committee of valuation practitioners to review and advise on approaches to valuation of Mineral Properties. The CIMVal Standards and Guidelines are organized into two parts: •,Standards which are general rules in the Valuation of Mineral Properties. The use of the Standards is mandatory if the Valuation Report is stated to follow CIMVal (although not mandatory in the sense of having regulatory authority). Definitions are given at the beginning of the Standards. •,Guidelines which elaborate on the Standards and, while not mandatory, provide guidance and best practices which are highly recommended to be followed in the Valuation of Mineral Properties.CIMVal specifies requirements for the Qualified Valuator who has the responsibility for choosing the appropriate approaches and methods for the valuation of mineral properties. With regard to the specifics of the application and practice of valuation approaches and methods, CIMVal directs the Qualified Valuator to the large body of published papers, published valuations, presentations and court judgments to guide his or her choice. This is also the approach taken by VALMIN (Australia) and SAMVAL (South Africa). To facilitate the dissemination of industry practice, the CIMVal Committee organized a “Valuation Day” at the CIM Annual General Meeting in Toronto (Mining Millennium 2000), on March 8, 2000. Industry experts presented papers on valuation of Mineral Properties which were subsequently published in a proceedings volume and individually ad technical papers in the CIM Bulletin. The Management and Economics Society of CIM has continued to identify and publish papers on valuation in the CIM Bulletin and Magazine. The present document gathers in one place the CIMVal Standards and Guidelines, the papers from the 2000 Valuation Day, and a number of subsequent papers that illustrate industry practice for the valuation of mineral properties."

Jan 1, 2003

By S. E. Knalafalla

The availability of a fluid whose gross behavior sharply changes in a magnetic field without affecting its rheologic characteristics has been recently demonstrated. A colloidal solution of a ferrimagnetic material, such as magnetite, in a liquid that is immiscible with and lighter than water is projected for use in selective separation of particles according to their density spectrum in a continuous fashion. Magnetic levitation forces were created as an antigravity field when the fluid was properly placed in an inhomogeneous magnetic field. Five spherical non¬magnetic objects with densities ranging from 2.70 to 11.35 gram cm ' were made to float or submerge at will in a 0.96-gram cm-3 density fluid placed at vertical magnetic field gradients ranging from 0.2 to I kilooersted cm-1. The magnetic levitation farce in dyne cm-3 was found to vary linearly as a function of the object-fluid density mismatch with a slope equal to one g, the acceleration due to gravity.

Jan 1, 1972

By J. Rao Mokka

Extensive exploration has resulted in delineation of a massive sulfide district on the north flank of the east-central Alaska range. The district covers approximately 400 square miles and contains numerous stratiform; transported and some replacement type sulfide deposits ranging in size from less than 1 million tons to 20 million tons. Five types of ores were sampled for the study. Mineralogical analysis revealed that the minerals are too fine grained for conventional grinding and beneficiation. Hydrometallurgical studies were con-ducted using ferric chloride as a lixiviant. Ore microscopic studies as well as electron microprobe analyses of minerals in the raw samples and leach residues explained the low recoveries for certain elements as well as sources of impurities that need to be eliminated from the process streams.

Jan 1, 1991

By Brian Wingfield, Rick Givens, Greg Williams

Many technological advancements have been made in explosive products and applications over the last 15 years resulting in productivity and cost gains. However, the applications of total energy (engine horsepower) in the majority of rotary drilling technology, has remained virtually unchanged over that period. While advancements have been made in components, efficiency, and types of hydraulic systems used on drills, the application of current hydraulic technology to improve drilling productivity has not been interactive with end users. This paper will investigate how traditional design assumptions, regarding typical application of horsepower in current rotary drill systems, can actually limit productivity.

Jan 1, 1996