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By A. A. Abdul-Latif, A. Sahin

"The phosphate deposit, located in the Abu Tartur plateau between the Kharga and the Dakhla Oases in the southern part of the Western Desert of Egypt, is the largest of its kind in the country. The phosphates are found in two horizons referred to as the Lower and Upper Phosphate Horizons within the Late Campanian Sibaiya Formation which belongs to the Nubia Group.This paper presents the results of a geostatistical study on the main phosphorite bed at the base of the Lower Phosphate Horizon which contains almost all the commercial reserves in the area. After semivariogram modeling for the phosphate thickness and accumulation, ordinary block kriging was employed to estimate the values of these variables in blocks of400 m by 400 m dimensions. The kriging results, which are presented in the form of contour maps, can be of considerable use in both future exploration and exploitation of the deposit. The grade-tonnage relationship based on the grade estimates derived from the corresponding thickness and accumulation estimates indicates the existence of 453.9 x 105 tonnes of phosphate above a cut-off grade of 18% P2O5. The mean grade of this tonnage has been estimated to be 25.77% P205"

Jan 1, 1990

By J. B. Morrow

Methods of Coal Preparation Fundamentally, the object of coal preparation is to increase, economically, the value of a fuel by making it more suitable to the uses of the consumer. This can be accomplished in three major ways: 1.Screening or sizing 2.-Mixrng or blending 3.-Cleaning By combinations of any or all of these methods we can prepare coal to meet standard specifications-a process of standardization which is the more desirable the more nearly it approaches the unvarying quality of packaged goods, where the package you buy today and tomorrow is the same as that you bought yesterday. It should be noted that it is readily possible to get good cleaning and still have poor preparation because of faulty screening and mixing, and, on the other hand, it is possible to get a passable grade of cleaning, combined with good screening and mixing facilities.

Jan 1, 1931

By David Runnels

The Mount Wright iron are mine and upgrading plant were brought on line in the fall of 1975. The mine is located near the Quebec - Labrador border some six hundred miles northeast of Montreal. This paper describes the crushing, grinding and concentrating facilities at Mount Wright, and some design: criteria used in equipment selection and flow sheet design. Also mentioned are some "asbuilt" modifications. A brief description of the over-all flowsheet is also included. Introduction IN SEPTEMBER 1970, the Quebec Cartier Mining Company started development of the Mount Wright iron ore mine. The estimated are reserve is in excess of 1,000,000 ,000 long tons of concentrates, with an average crude are grade of 31.5% Fe. The run-of-mine ore is crushed, ground and concentrated to a product having 66% Fe and 5% silica at an annual concentrate production r ate of 18.4 million long tons. The daily production rate of over 50,000 long tons of concentrate necessitates a daily mine output of approximately 250,000 long tons of material, of which 50% is waste.

Jan 1, 1977

By Eugene T. Sheridan

The process of converting coal into coke is known as carbonization. Essentially, carbonization is destructive distillation in which the volatile matter of coal is released when coal is heated above its decomposition temperature and passes through a plastic stage before solidifying and forming coke. The mechanics of coke formation are complex, and the specific properties of certain coals that allow them to "cake" or form coke are still unknown. Coke is a hard, cellular, carbonaceous mass, formed by heating coal in the absence of air. It is porous, irregular in size and shape, and is similar in appearance to wood charcoal. Coke, however, is denser, more porous, and more abrasive than charcoal.

Jan 1, 1965

"INTRODUCTIONThe Kidd Creek Concentrator is located 28 kilometers east of the city of Timmins, Ontario. Two types of ore are treated; 'A' type, a copper-zinc-low silver ore producing copper and zinc concentrates, and 'C' type, a copper-lead-zinc-high silver ore producing copper, lead and zinc concentrates.The ore is processed at a combined rate of 12,400 metric tonnes per day through four parallel grinding and flotation divisions. Three divisions treat the 'A' type ore and the fourth treats the 'C' ore. Each division is fed from its own fine ore bin.This paper reviews the grinding section with specific emphasis on grinding media consumption and the factors affecting it as related to 'A' type ore. At Kidd Creek there was an awareness that grinding media consumption varied on a weekly and monthly basis. The reasons for this variation was usually attributed to ore hardness as evidenced by short term variations in the circuit feedrate and head assays. However, there has been a diversity of opinion published in recent years regarding the factors contributing to steel consumption. This initiated a study of historical Kidd Creek operating data, from the period 1970 to 1986 inclusive, to determine the effect of various operating parameters on media consumption. The results of the study could then be used as a baseline for future media consumption testwork."

Jan 1, 1988

The propensity of coal spontaneous combustion can be evaluated using various laboratory testing methods such as R70 adiabatic tests, thermal gravimetric analyzer (TGA) and critical self-heating temperature (CSHT) methods. Each of the methods has its unique characteristics and index for classifying the propensity of self-ignition of coals. Accountable relationships among the propensity indices of different methods should be established. Using the newly established R and TGA testing setups in our ventilation laboratory, samples from US coal mines have been collected and tested. 70 The TGA is a relatively new quantitative method. A test can be conducted in a relatively short time. The temperature and weight of the sample can be measured with high precision and then used to determine the activation energy of the coal which is a good indicator for potential of self-heating. Under a specific experimental design, the TGA technique could perform the proximate analysis for determining coal quality parameters (e.g., moisture, volatile matter, fixed carbon and ash content). These parameters can be used in an empirical equation for assessing the potential of coal self-ignition. The trend of activation energies determined using TGA techniques and adiabatic tests are reasonably consistent with each other. As a case study, a comparative analysis of these two methods for determining activation energy was made on coal samples collected from Indiana. The kinetics of the spontaneous combustion mechanism has been explained. If the functional groups of a coal are easier to be activated with a small amount of activation energy at a relatively low temperature, the coal will has a higher potential of self-heating. With the kinetic and coal quality parameters determined by the TGA setup, it has been found that the coal with low potential of self-ignition has low self-heating rate, high activation energy and high minimum self-heating temperature.

Jan 1, 2012

By G. R. Hopkins

According to reports received by the Bureau of Mines, Department of Commerce, as of January 1, 1929 there were 413 completed refineries in the United States, with a total daily crude-oil capacity of 3,509,540 barrels. In addition, 14 refineries, with a potential capacity of 99,000 barrels, were being constructed. Of the completed refineries, 341, with a capacity of 3,325,890 barrels, or 95 per cent of the total capacity, were in operation; and 72, with a capacity of 183,650 barrels, or 5 per cent of the total, were shut down. The improved condition of the refining industry in 1928 was indicated in several ways; namely, in an increase in the total capacity of the completed plants, in the opening up of a few plants which were shut down during 1927, in a decrease in the number of plants dismantled, and in an increase in the number of plants under construction. The majority of the refiners have followed a steady expansion program commensurate in most cases with the increase in demand for petroleum products. Obsolete equipment has been dismantled and modern equipment has been installed, with the net result that the total capacity of the completed refineries in the United States has shown a steady increase since January 1, 1918, the date of the first Bureau of Mines survey. Between January 1, 1928, and January 1, 1929, the number of completed plants fell from 423 to 413, but their total capacity increase 259,160 barrels, or 8 per cent. This compares with an increase in runs to stills of domestic and foreign crude petroleum of 10 per cent, and of domestic crude alone of 7 per cent.

Jan 1, 1929

By V. T. McLemore

In-situ leaching (ISL) operations have been proposed to recover uranium from sandstone-uranium deposits in NM. ISL (also known as in-situ recovery, solution mining, solution-leach mining, leach mining) consists of injecting a leaching solution into the mineralized zone through injection wells. The leach solution migrates through the formation, dissolves uranium and is recovered through production wells. The uranium is then precipitated through a conventional uranium recovery system. Several criteria must be met in order for in-situ leaching to be successful, most important is that the ore body must be amenable to chemical leaching. A number of ISL operations have been conducted in NM in the past (Mobil, Crownpoint; UNC-Teton, Section 23; Grace Nuclear, Hook?s Ranch, Seboyeta, Church Rock; Anaconda, Windwhip). Kerr-McGee (later Quivera Mining Co., Rio Algum) successfully produced uranium from mine-water recovery (recirculated mine water) from the Ambrosia Lake mines (mid-1960s to 2002). Despite some difficulties, ISL is a viable alternative to recovering uranium and could be utilized in the Grants district with proper aquifer characterization and monitoring.

Jan 1, 2009

By Xiao Caimei

The method of Substance Flow Analysis (SFA) provides a helpful tool for the study of the industrial metabolism of a certain metal within a regional level, such as copper, lead etc. In this paper the flows and inventory of cobalt in China, 2008, were traced with the STAF model, and the situations of production, fabrication and manufacturing, use and waste management in China were introduced. The result revealed that the resource of cobalt in China was so poor that a large amount of cobalt material or cobalt products needed to be imported, and there was lack of recycling of cobalt resources.0

Jan 1, 2010

Report M48 Tracer tests on furnaces at M etalloys Limited. Report M52 A high-speed, multi-input serial-interfacing system for a computer with simultaneous back-1lP recording on magnetic tape. Report M53 The development of an automatic sample-changer and control instrumentation for isotope-source neutron-activation analysis. Report M69 The determination, by X-ray-fluorescence spectrometry,of tin and tungsten in ores, concentrates, and residues of scheelite, wolframite, and cassiterite. Report M77 Analysis of the results of a marked-ball test in relation to theories of ball wear in rotary mills.

Jan 1, 1983

By William F. List, Marvin A. Schuster

Monolithic electrooptical mosaics of 2500 photo-transistor elements with internal row and surface column interconnections have been fabricated by epitaxial-planar diffsion techniques. Unique access to any elemed of the mosaic is provided through one of the fifty X and one of the fifty Y external leads. The sensor mosaic can be used for imaging applications and has a 1:1 aspect ratio, a resolution of 100 lines per in., a dynamic range in excess of lo3, a sensitivity of 0.5 per pw, element response within a 2:l range over 75 pct of the mosaic, and a minimum detectable signal of the order of 10-' w. Design considerations which ilnpose particclar fabrication yequirements are disctussed along with some of the problems peculiar to the epitaxial and planar-dijfision techniqes by which this device is fabricated. The solid-state silicon monolith has an imaging area of 0.5 by 0.5 in. and an element center -to- center spacing of 0.010 in. J monolithic solid-state electrooptical device has been developed as the photon-sensing mosaic for use in an image-converter system.' This system is the solid-state equivalent of the vidicon and can image radiation in the visible and near-infrared regions of the spectrum. The electrooptical image converter has the desirable size, weight, reliability, and low-power characteristics inherent in solid-state devices. It is read out by direct-wire means rather than by beam-scan techniques. The packaged unit is shown in Fig. 1. A selection of material for the sensor was based on considerations of both reliable fabrication techniques and material spectral response. Silicon was selected both for its response from the lower end of :he visible to the long-wavelength cut-off above 11,000A and for its well-developed epitaxial planar-diffused technology. The electrical image is composed of M x N discrete information bits with each bit emanating from one of the individual phototransistor sensors. The interconnected mosaic concept was introduced to provide a structure which is both manageable in its number of leads and compatible with conventional viewing systems which accept XY data. Interconnections along the Y direction are provided by internally diffused strips, while interconnections along the X direction are formed by vacuum-deposited metal surface bars. Unique access to any individual element of the M x N mosaic is available through one of the M and one of the N external leads. PHOTOTRANSISTOR DESIGN A phototransistor structure2 was selected for the discrete photon detectors of which the mosaic is com- posed. Basically, the mode of phototransistor operation is such that incident quanta are absorbed in the base area of the element where they generate electron-hole pairs. If the electrons are liberated within a diffusion length of the depletion region around the collector junction, they will diffuse to this depletion region and be swept across the junction where they account for a small component of the photocurrent. Similarly, the holes which are created within a diffusion length of the emitter junction will diffuse to this region where they forward bias the emitter and so induce injection of minority carriers into the base. This accounts for the substantial transistor photocurrent. This mechanism of operation implies several design and fabrication goals for the individual sensor elements: high electrooptical conversion efficiency, sufficient carrier lifetime in the base regions, and a maximum volume in which photons can be absorbed within a diffusion length from the depletion layer about the junction. Moderately high transistor gain is desirable to permit readout at low light levels; however, very high gain has a deleterious effect on mosaic dynamic range. The mosaic must also be characterized by good uniformity of element response as well as by good isolation between elements. The above set of conditions imply that junction depths must be optimized with respect to photon ab-

Jan 1, 1967

By Eugene T. Sheridan

The process of converting coal into coke is known as carbonization. Essentially, carbonization is destructive distillation in which the volatile matter of coal is released when coal is he ted above its decomposition temperature and passes through a plastic stage before solidifying and forming coke. The mechanics of coke formation are complex, and the specific properties of certain coals that tallow them to "cake" or form coke are still unknown. Coke is a hard, cellular, carbonaceous mass, formed by heating coal in the absence of air. It is porous, irregular in size and shape, and is similar in appearance to wood charcoal. Coke, however, is denser, more porous, and more abrasive than charcoal.

Jan 1, 1965

By K. Mikulash

"Agnico-Eagle Mines Limited is located at Joutel in North-Western Québec. The mine is about four miles north-west from the town on the left bank of the Harricana River. The present mining is 1,800 feet deep with an extensive geological development below this level.HISTORY The development of the ore body started sometimes in 1967 and then the operation ceased in 1969 and again reopened in 1973 due to higher prices of gold. During these periods of active development, a considerable metallurgical research has been done by different laboratories and research and design companies.The original capacities of the Mill differed as much as 30%. So did the concept of the ore treatment. The original design of the mill was for 200 TPD of ore with straight cyanidation. The problems with low gold extraction, high reagent consumption and poor filtration resulted in a decrease of the expected mill output to an initial 550 TPD with gold recoveries in the order of 40 to 60%.Although the studies and research work done on the ore varied, all of them had a common conclusion: a very fine grind is needed to expose gold. The mining method (sub-level blast hole mining) now provides the ore that differs from that on which the metallurgical test work was conducted and the original capacity calculations had been done.These variations in the concept consequently led to the conclusion that the size of gold is a determining factor for the process.Kilborn Engineering provided the original design with the Leslie Eng¬ineering completing the design. The metallurgical test work has been done by the Department of Energy, Mines & Resources, Lakefield Research of Canada, Kilborn Engineering and Sidam Incorporated.The new flotation section with secondary grinding has been designed and put into operation by the company in December 1975 with the results yet to be evaluated."

Jan 1, 1976

In west-central England, 183 m (600 ft) below the Cheshire Plain, lie the evaporate remains of an ancient sea. Stratified into nine beds of salt separated by marl bands, the deposit stretches roughly 21 x 12 km (13 x 7.5 miles) and contains reserves of rock salt estimated as high as 400 Gt (440 billion st). The Winsford Salt Works, one of England's largest underground mines, extracts the Cheshire salt and sells it for use as animal feed, for application in de-icing programs, and as a key ingredient in sodium fertilizer production and a variety of other industrial processes. Because road de-icing is an important market, demand for Winsford's salt varies with the severity of British winters. Design capacity is 2.25 Mt/a (2.5 million/year). However, production peaked at 2 Mt (2.2 million st) in 1987. Over the past five years, annual production has averaged 1.6 Mt (1.7 million st). Run-of-mine salt averages 92.5% NaCl, mixed with about 5% marl. The marl was formed by deposition of a reddish dust blown into the Cheshire basin from deserts in what is now central Europe. Association with the marl adds color to the salt, producing tea-colored crystals that resemble unrefined sugar. Adaptation of coal mining systems Rock salt mining in the Winsford district began at least as early as 1682. Mining at the current site dates from 1844 but was shut down from 1892 to 1928. In the early 1900s, a series of catastrophic collapses and floods plagued and ultimately shut down then-active Cheshire brine-salt producers. Subsequently, Winsford reopened and began adapting mechanized underground coal mining systems to rock salt extraction.

Jan 1, 1992

By R. W. Michelson

The Bureau of Mines developed computerized mathematical models to estimate the economic availability of Mesabi Range taconite concentrates; these are a quality model, a cost model, and an economic availability model. The quality model evaluates metallurgical test data; the cost model determines iron unit cost from mining and processing cost data; and the economic availability model determines quantity from geologic and ore quality data. By correlating all of the physical resource quality factors and dimensional characteristics with the economic cost factors associated with producing iron ore pellets, these three models combine to establish a final relation between iron ore reserve quantities and iron unit cost.

Jan 1, 1970

By IPMI Educational and Scientific Foundation

It is with great pleasure that we announce the availability of this fourth issue of the IPMI Journal, a publication of the International Precious Metals Educational and Scientific Foundation. This digital peer reviewed publication has been created as a vehicle for the sharing of technical information related to the science and technology of precious metals. Since 1976, the International Precious Metals Institute has championed the exchange of information of critical importance to the precious metals scientific and commercial communities through its various communications vehicles. This has included instructional videos, annual conference symposia, special topic committee meetings, regional seminars, and professional and student achievement awards. Due to the breadth of important topics related to all aspects of precious metals, it has been the vision of the IPMI to provide a publication available to the general public that would become a key source of pertinent topics containing high quality publications by experts in their fields of study. Historically, the IPMI has attracted world renowned experts in many fields (including Nobel Laureates Henry Taube, Ei-ishi Negishi, Robert Grubs, Professor Ben Feringa, and David MacMillan) in the dissemination of discoveries, inventions, and industry proven practices. Such information has a total value greater than the sum of its parts as seemingly unrelated innovations from distinct focus areas can be adapted to solve problems. Because of this important characteristic of information exchange, we have decided to create a digital journal, available to the general public, that will not only communicate state of the art discoveries and sound practices, but will also review historical communications from the IPMI’s archives that have value and use even in today’s environment. On behalf of the members and leaders of the IPMI, we hope you will find value in this new publication.

Dec 1, 2022

By R. Schuerch, C. Cimiotti, G. Anagnostou, J. Nickerson, P. Perazzelli

"This paper presents experiences gained from the construction of the Lake Mead Intake No. 3 project. The 4.7 km long tunnel was excavated with a hybrid TBM (able to operate in both closed and open mode). The tunnel crossed metamorphic and sedimentary rocks under a hydrostatic pressure of about 14 bar. During the excavation of the tunnel the TBM encountered difficult ground conditions caused by a combination of high water pressure, poor ground quality and locally low depth of cover. The adverse conditions required the TBM to be driven in closed mode at very high support pressures (10 – 15 bar) for approximately 60% of the tunnel length. The paper summarizes the main problems encountered during TBM excavation and analyzes the evolution of the TBM parameters over the entire tunnel length. INTRODUCTION The Lake Mead Intake No. 3 project is located approximately 30 km away from the city of Las Vegas in Nevada, USA. The project consists of the construction of a deeper third intake for the biggest reservoir in the United States, which is formed by the Hoover Dam. The construction of the new intake was required due to the constant drawdown of the lake level (more than 40 m in the past 20 years) and the consequent risk that the shallower intakes 1 & 2 may run dry. The project included the fabrication and positioning on the lake bottom of an intake riser, the excavation and lining of a 185 m deep shaft and construction of a 4.7 km long tunnel. One peculiarity of the project is that the water table is located about 140 m above the tunnel elevation (i.e. corresponding to a hydrostatic pressure of 14 bar at the current lake level). The tunnel was constructed using a tunnel boring machine (TBM) able to operate in both open and closed mode (Mc Donald & Burger, 2009). The present paper focuses on the TBM tunneling experience gained from the Lake Mead Intake No. 3 tunnel. The TBM excavation started on December 27, 2011 and finished on December 10, 2014 with the breakthrough to the intake structure at the bottom of Lake Mead. GEOLOGICAL CONDITIONS The assessment of the ground conditions encountered during construction was mainly based upon qualitative descriptions of the tunnel face conditions (during open mode operations) and analysis of the extracted muck (during closed mode operations)."

Jan 1, 2016

By Jiang Diao, Yong Qiao, Xuan Liu, Tao Zhang, Bing Xie

Adding CaO into the vanadium extraction converter is an effective way to decrease the dephosphorization burden in subsequent steelmaking process. The crystallisation process of spinel is one of the most decisive factors in the subsequent extraction. The theoretical calculation results show that the temperature of the peak total crystallization rate will decrease 5K with basicity increasing 0.1. The relation between cooling conditions and grain size of spinels is also discussed. It is found that low cooling rate and high basicity benefit spinel crystal growth. And the non-isothermal crystallization kinetics results indicated that the restriction factors of spinel growth is that solid crystals accept new components from liquid-solid interfacial. While the sample was cooled down to 1250 (1523K) at cooling rate of 5K/min, the crystal growth is consistent with Ostwald coarsening grew up law, and controlled by diffusion of particle.

Jan 1, 2016

By Jan H. Hommen

TRENDS IN MINE FINANCE Reviewing historical trends may help in dealing with future funding strategies. The first trend is the increase in the use of debt to fund corporate America. Surprisingly, when comparing that with other corporates in the global marketplace, the U.S. does not look too poorly. Japanese, in particular, but also German companies, are much more leveraged than their U.S. counterparts. Note that in Japan and Germany the government and the consumer have shown substantial restraints when it comes to credit. Not so in the U.S. where the savings rate (4%) is much lower than that in Japan (20%) and in Germany (14%). As a result, the cost of leverage is substantially lower in Japan and in Germany than in the U.S. Lower debt costs in these countries allows one to obtain more of it for the same price. The close relationships between financial institutions, corporations and governments in Japan and Germany also make the risk of leverage more bearable and understandable. Also note that interest rate volatility in these countries is more subdued. The investor base in common stock is also changing. Private pension funds have been net sellers of equities during the last few years while public pension funds have been net buyers. Individuals are basically out of the market. It is estimated that over $330 billion of equity was retired in the U.S. through 1986-1988. The reasons are well known: restructurings, buy-backs, takeovers, mergers, and buy-outs. This de-equitization is likely to continue as the cost of equity capital is higher than the cost of debt capital, even on a before-tax basis. Because there has been no market for equity since October 19, 1987, junk bonds have replaced equity capital in the corporate finance structure. The non-investor-grade borrower has access to the public markets through high-yielding debt securities that often look like senior equity. Deregulation has also provided 24-hour markets; securitization can now liquify assets that before were rusting on balance sheets; information processing and communication tools give facts that are instantaneously available, creating the need for products to cover risk and exposures unknown before the start of the information and technology explosion. Thus we now have swaps, options, futures, options on futures, caps, as well as program trading, portfolio insurance, index funds, etc. Globalization will be unstoppable. Today's environment demands it. Corporations are now global competitors, even though they may have never shipped a product off-shore. Boundaries are disappearing and impediments have been removed. Stocks can be issued in a global offering with distribution in all major financial centers of the world. The high leverage of Japanese companies has made common stocks very scarce, which with the high savings rate, makes equity capital inexpensive in Japan. If markets were perfect everyone would issue stock in Tokyo and buy it back in New York. This would certainly stop the bleeding on the balance of payments. With the deficit balance of payments in America, it is no surprise that the cost of money is expensive here. The risk-return relationship on U.S. equity is not favorable enough to appeal to Japanese equity investors. The Tokyo-market, helped by a stronger yen, surpassed New York as the most important equity market in the world. The question is, will the Tokyo market hold up when Japanese domestic consumption increases at the expense of savings? In the U.S. debt markets, the plain vanilla debenture is making a comeback after a period of absence. Commercial paper has replaced short term bank borrowings for working capital funding by larger corporations. The banks have made an interesting comeback with loan sale programs that will continue to attract borrowers. There will be a continuing

Jan 1, 1990

Experimentally determined and theoretically explained phenomenon of zonal disintegration of rock around the development working brings about the radical changes in existing ideas about the mechanism of interaction rock massive with engineering constructions.The essence of the phenomenon consists in the fact, that forming of non-elastic deformations zone goes on by way of more intensive deformation and destruction of rock simultaneously in several zones, covering partially or fully output circuit and divided by zones of destructed rock. Under the influence of change of massive strained-deformational condition of depositional rock an accidental deviation of zones of supplementary expansion and compression of rock from the previous positions take place. One can observe multiplicational change of the outline, size and form of all disintegration zones in the time within the area of the working influence at massive. This phenomenon was named "fluctuation of zonal disintegration of sedimentary rock around development working".

Jan 1, 1991