Search Documents

By S. H. Ash

THE BARRIER-PILLAR SYSTEM in the Lackawanna Basin consists of 93 barrier pillars between Archbald and Taylor, Pa. These pillars affect 48 mines, have a total length of 87 miles, and confine 21 underground pools, which contain more than 10 billion gallons of water. From an investigation of size, position, and condition of the barrier pillars, it is apparent that those concerned are uncertain, not only as to the method by which the sizes of the barrier pillars were determined but also as to the stability of those that may be expected to act as dams. Where a barrier pillar must act as a dam, its failure may result in loss of life, the mine, or both; it would be far better had it not existed and thereby given a false sense of security.

Jan 1, 1952

By J. L. Holman

The Bureau of Mines is conducting research to improve technology for the recovery of strategic and critical metals, such as cobalt, nickel, and chromium, that are lost in bulk and particulate superalloy-type scrap because it has not been possible to process mixed contaminated scrap efficiently. The research approach involves melting and casting mixed superalloy scrap into soluble anodes for electrodeposition of Ni-Co alloys by controlled-potential electrolysis. The initial experimental results described in this report are from electrolytic tests us-ing alloy anodes cast from elemental nickel, cobalt, and chromium, the main constituent metals of superalloys. Baseline data and operating parameters are necessary for Ni-Co and Ni-Co-Cr alloys before detailed experiments can be conducted on the more complex superalloy scrap. This basic research assessed the effects of cathode potential, S04:CI electrolyte ratio, electrolyte pH, stirring rate, deposition time, cathode current density, and chromium concentration on cathode current efficiency, alloy deposit composition, and deposition potential at a cell temperature of 55° C.

Jan 1, 1985

The Purification of Low-Grade Quartz Ore by Flotation and its Mechanism

Sep 13, 2010

TO THE. BOARD OF DIRECTORS AND MEMBERS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS GENTLEMEN Submitted herewith are the report of the Treasurer for the year 1945 and reports for the same year of the following committees: Membership, Admissions, Papers and Publications, Mining and Metallury (Magazine), and Library. In this review of the year by the Secretary reference frequently will be made to the "Paul" Committee and to the "hotter" Committee. The first is the special committee on Divisional Relationships and the second the special Committee on Ways and Means. These two important committees, appointed by President Harvey S. Mudd under authorization of the Board of Directors on March 21, 1945, were composed as follows:

Jan 1, 1946

By Sutham Niyomwas

The Fe-TiC composite powder was synthesized in situ by carbothermal reduction of ilmenite. The standard Gibbs energy minimization method was used to calculate the equilibrium composition of the reacting species. The effects of the reaction temperature (1300 °C - 1500°C) and milling time of precursors on the Fe-TiC conversion and powder morphologies were investigated using XRD and SEM method. The synthesized products showed that composite with iron matrix and titanium carbide as a reinforced phase was formed.

Jan 1, 2006

Implementation of an Energy Efficient Dry Grinding Technology into an Anglo-American Zinc Beneficiation Process

Sep 13, 2010

By Joe Pease

"The demand for minerals and metals is increasing. Head grades of ore bodies are dropping. Remaining ores are becoming finer grained, more complex, and more logistically challenging. Mineral processing – in particular comminution – already consumes a huge amount of energy. But in 20 years’ time, it will require about six times as much energy as today to meet the world’s mineral demand.Unless we do something different.As minerals professionals, it is our job to find that “something different”. The world is relying on us. Of course, we must look for new breakthrough technologies and techniques. We must find them, and we will find them – most likely in surprising areas.But what if we also already know how to make 30-50% improvements to efficiency? Just by using existing technologies, by applying modern analytical techniques, by custom designing our plants, by applying manufacturing principles, by breaking down our management silos between disciplines.The thing is, industry professionals already know this. Yet – in spite of a lot of intelligent people trying very hard – we just can’t seem to make it happen.This discussion considers why, despite our best efforts, we don’t get the best out of what we already have. Why we are wasting energy and money. Once we understand why, we can set about unlocking that value and improving industry productivity and energy efficiency. We will discuss the role that professionals and volunteer professional organisations like CMP and CEEC can play in catalysing the changes."

Jan 1, 2015

Ceremonies for the induction of five mining industry pioneers into the National Mining Hall of Fame will be on Sept. 12, 2009 at the Charles F. Barber Pavilion of the Museum Convention Center in Leadville, CO. The five inductees are: Paul A. Bailey, 82, Richard T. Moolick, 89, William Braden and Alonzo Pawling and Henry Harnischfeger. Paul A. Bailly was president of Bear Creek Mining Co., the U.S. exploration subsidiary of Kennecott Copper, from 1961 to 1967. In 1968, he joined Occidental Petroleum Corp. and was tasked with creating the company?s international mining division, Oxymin, which he led as president through 1983. During his distinguished career, Bailly participated in numerous significant mineral discoveries, developed a new exploration philosophy and made important additions to the mineral exploration literature. William Braden was the first to recognize the immense potential of the El Teniente orebody in Chile. He founded Braden Copper Co. and developed the El Teniente Mine which now, 100 years later, remains the world?s largest underground copper mine. Braden?s endeavor survives to-day as the El Teniente division of the Chilean state copper company, CODELCO. T. (Dick) Moolick established a lasting legacy in the mining industry, first during a 35 year career with Phelps Dodge Corp. and then as the driving force in establishing the National Mining Hall of Fame and Museum in Leadville. The Hall of Fame and Museum ? a monument to the memory of the men and women who pioneered the discovery and development of the United States? natural resources ? has become one of the fi nest museums in the western United States.

Jan 1, 2009

By Ronald M. Lewis

Quadratic functions, Q(hkl), are given to six places in increments of 0.01° for 2? from 00 to 90° for FeKa and from 25° to 180° for FeKa1. The wavelengths used for Fe in the computation are those agreed upon by the Editorial Commission of the International Tables for X-ray Crystallography (1950): FeKa1 1.93597 A.; Feka2 1.93991 A. INTRODUCTION At the Federal Bureau of Mines laboratory, Norris, Tenn. X-ray diffraction crystallography using tubes with iron targets revealed a need for a handy reference for the quadratic functions of iron radiation. The tables presented here were prepared to satisfy that need. The quadratic form Q(hkl) may be expressed in terms of the Bragg diffraction angle 2? and of the wavelength ? as

Jan 1, 1961

By T. B. Acton

There are two types of ore transportation systems in use at Newmont's Magma Copper Co. San Manuel mine in Arizona-rail-mounted, box-type rotary cars and the newer rail-mounted, bottom-dumping ASEA cars. Though the cost per car for the ASEA units greatly exceeds the cost per rotary car, the advantages of the ASEA units, including much faster dump times, have made the ASEA system a successful alternative at the San Manuel mine. The rotary system of ore transportation has been in use at San Manuel since production began in 1956. The system employs 7.9-m3 box-type cars to transport ore by rail to shaft pocket areas. A rotating dumping mechanism turns three cars at a time upside down to empty them, and returns them to an upright position. Trains of 15 cars each are dumped in about six minutes. Each 15-car train is pulled by an 18-t rated trolley locomotive. There are about 400 rotary cars in service at San Manuel and the system is used for the majority of ore haulage. This well-proven rotary method was instrumental in achieving the December 1977 world record of 272 Mt hoisted from an underground copper mine. Magma Copper Co. began using ASEA cars in late 1977. Designed by ASEA of Sweden, the cars are built for San Manuel by Kasper-Hall Manufacturing Co. in Tucson. The cars basic design feature is a hinged floor that opens at the side as the car is pulled through the dump. As it passes over the dump, a fifth wheel attached to the hinged floor (opposite the hinges) travels along a rail in the dump. This rail dips down into the pocket and then returns to track level. As the fifth wheel travels along the rail, the car floor opens, the car dumps, and the floor is then returned to track level. As the car is dumping, the body remains suspended over the pocket by wheel rollers attached to each side of the dump. Trains of 10 cars each are emptied in about 45-50 seconds. Each ASEA train is pulled by an 18-t rated trolley locomotive, adapted at San Manuel to allow it to pass through the ASEA dump. At minimal cost, "wings" are welded to each side of the locomotive. These wings suspend the locomotive over the pocket as the train passes through the dump. Advantages of the ASEA System Major design characteristics of the ASEA and rotary systems are shown in the accompanying table. The comparison points out some of the following advantages demonstrated by the ASEA system. • Faster dumping-An ASEA train dumps in 50 seconds, while a rotary train takes at least six minutes. There is no stopping or starting when dumping an ASEA train. The train enters the dump area, dumps, and leaves in one continuous motion-in contrast to rotary trains which must stop and start five times to dump. With the rotary system, three cars are spotted in the dump mechanism by remote control. When the cars are in place, the train operator activates the dump, the cars are turned over, and then returned to an upright position. This process is repeated until all 15 cars in the train are emptied.

Jan 4, 1980

By Robert F. Randolph

Real-world levels of attenuation from hearing protection devices are usually much lower than the rated values obtained under near-ideal circumstances. The shortfall is even more extreme for earplugs than it is for earmuffs, primarily because of the complicated process of fitting the plugs within the ear canal. This study examines the use of a commercially-available lubricant for hearing aids to determine whether it would facilitate improved fit and attenuation for earplugs. In this experiment, ten participants inserted earplugs with and without using the lubricant. Average attenuation was assessed with the Real-Ear-Attenuation-at-Threshold (REAT) technique, and showed over 5 dB improvement when the lubricant was used. Participants obtained an 85% mastery rate using the lubricant versus a 50% mastery rate without. These results indicate several possible applications for improved earplug performance in real-world settings where hazardous noise is unavoidable and effective hearing protection is necessary.

Jan 1, 2008

By S. Babendererde

The twenty-ninth Sir Julius Wernher memorial lecture of the IMM, presented at Tunnelling '97, London, 2-4 September 1997. The tunnelling industry is well prepared to face the challenge from the population explosion in urban areas in the near future. Many well-established yet redundant concepts are still impeding progress, however, including the prediction of excessive surface ground settlements. The correct selection of TBM can minimise these, and ground deformations can be avoided completely if the appropriate techniques are applied. Advanced techniques have been used in the Tokyo Bay Crossing, where the tunnel lining was installed by robots. Other advanced techniques include the use of a sliding slip form to give temporary support to an extruded tunnel lining, the chemical processing of ground by polymers during earth-pressure balanced tunnelling and the use of electronic monitoring and steering devices in TBMs. There will be challenges to tunnelling in urban environments, as open cut techniques will no longer be tolerated. Two examples of mined stations are briefly discussed

Jun 19, 1905

By Gary A. Kingston

Low-cost hydroelectric energy in the Pacific Nortnwest has been an important factor in the development of a ferroalloy industry. Eleven companies, employing approximately 1,000 persons, produce about 116,000 tons (1954-58 average) annually of ferrosilicon, ferrochromium, ferromanganese, ferrophosphorus, silicomanganese, and ferronickel. About 7,500 tons (1954-58 average) of these ferroalloys is consumed in the Pacific Northwest States of Washington and Oregon; the rest is used principally in other western and mid-western markets. In 1959, the Bureau of Mines began a study to determine the current status and to evaluate the potential of the ferroalloy industry in the Pacific Northwest. The Bureau gathered information from operating alloy plants in Oregon, Washington, Idaho, and Montana; from published materials; and from consumers of ferroalloys.

Jan 1, 1962

By N. B. J. Kieser

Paper presented at the IAGOD international symposium on mineralization related to mafic and ultramafic rocks, held in Orleans, France, 1-3 September 1993. Platinum-group minerals (PGM) in the enriched zone at Dust Mountain occur in two separate parageneses, the first representing primary magmatic PGM and the second primary magmatic PGM that have been reduced to alloys during serpentinisation. Minerals in the first group were unaffected by hydrothermal alteration on account of their textural setting or stable chemical composition. Despite substantial alteration of the serpentinised assemblage, most evidence points to the dominant role of primary magmatic processes in determining PGM occurrence. Several base metals have nevertheless been introduced hydrothermally. With respect to surficial dispersion the single most important paragenetic factor was the reduction of sulphides to alloys, rendering them more susceptible to mechanical erosion and less so to chemical leaching. The different textural setting of Pd-group and Ir-group phases results in different dispersion characteristics, with major implications for stream sediment sampling

Apr 1, 1994

By H. H. Dewing

The Bureau of Mines constructed a process research unit (PRU) to demonstrate new technology for extracting zinc from sphalerite concentrates. Up to 9 kg/hr of sphalerite (ZnS) concentrate was reacted at ambient pressure in the PRU with 80 pct sulfuric acid at 160° to 180° C to produce zinc sulfate and elemental sulfur. The PRU consisted of a three-stage glass reactor system: a 4-liter premix stage in which feed was slurried with 78 to 82 pct H2S04, a 40-liter stirred reactor, and a ISO-liter settling stage in which high reaction conversions were effected and excess H2S04 for recycle was separated from insoluble ZnS04 and sulfur. Evolution of sulfur-containing gases was minimized by sub-surface addition of acid feed slurry to the stirred reactor and by exclusion of air from the reactor to prevent the oxidation of elemental sulfur. Conversion of zinc to zinc sulfate averaged over 99 pct at the optimum acid concentration of 80 pct. Total sulfur losses (primarily S02) were less than 2 pct of the sulfur in the sphalerite. Elemental sulfur remained in the insoluble portion of the settled reactor product after leaching with simulated spent zinc electrolyte containing sulfuric acid. The sulfur residue contained 75 to 89 pct sulfur. Neutral zinc sulfate, required for zinc electrowinning processes, was separated from the sulfuric acid leach solution by crystallization at -15° C as zinc sulfate heptahydrate (ZnS04?7H20). The crystallization operation simultaneously effected a partial concentration of the recycled electrolyte solution by removing water.

Jan 1, 1982

By Jinwu Kang

The hydraulic turbine blade of the matensitic stainless steel (Cr13%,Ni5%,Mo1%) is a kind of large and curved shape, which is susceptible to deformation in both casting and heat treatment processes. The coupling analysis of heat transfer, phase transformation and stress in heat treatment process of the turbine blade for Three Gorges Project is carried out by using Deform-3D software. Its temperature fields, phase fields and stress fields in heat treatment process are obtained. And its deformation is predicted. In the cooling process of normalizing, the blade exhibits relatively large deformation. Based on the stress analysis and deformation prediction in heat treatment process, an algorithm for the determination of reverse deformation of the blade casting in heat treatment process is presented. And the reverse deformation distribution of blade is obtained.

Jan 1, 2010

By G J. Corbett, P Magner, M McKenzie

Structures formed during ductile deformation have been reactivated during the later brittle mineralisation process. Two generations of folding are classified as: early recumbent megascopic FI folds and FI shears which transpose the hinge regions, and later upright F2 folds. S1 is folded about F2 folds which contain axial planar S2 crenulation cleavage. Vergence relationships between S1 and bedding indicate that many of the mineralised structures occupy sites of FI folds which have acted as plumbing systems for later gold mineralisation (eg Blackwater mine). The Globe-Progress gold mineralisation is localised by a major jog formed by sinistral strike-slip movement on two FI fault segments and mineralisation also occurs in smaller jogs along strike (eg Sir Francis Drake, Happy Valley-Merrijigs, Cumberland).   The lodes of ribbon quartz which exploit the FI shears and local bedding planes, are inferred to have mostly formed after the peak of metamorphism, possibly related to the emplacement of Carboniferous granites. This was followed by a sequence of vein deposition and wallrock alteration which consists of quartz-As/Fe sulphides ? carbonate - stibnite ¦ trace base metal sulphides and Bi-sulphosalts ? illitic clay/sericite-chlorite. Gold at Globe-Progress is mainly encapsulated in arsenopyrite. At Blackwater, free high fineness gold occurs in partings in lode quartz with late sericite-chlorite. The above sequence of events is comparable to that encountered in many intrusion-related gold systems throughout the Southwest Pacific region. There is a spatial relationship between gold mineralisation and dykes variably described as diabase, dolerite or lamprophyre. Alkaline rocks occur in many Pacific rim and older goldfields and may possibly be related to a magmatic source for gold mineralisation.

Jan 1, 1997

By Alfred V. C. Meyer

A Blastcorder4 was calibrated on the Bureau of Mines shaking table in the frequency range of 12 to 40 c.p.s. and in the amplitude range' of 0.25 to 1.0 g. The results of this calibration study show that in the frequency range of 12 to 30 c.p.s. the average accuracy of the Blastcorder is approximately ± 0.1 g.

Jan 1, 1962

By Xiao Min You, D. R. Swonbourne

Smelting of Cu anode slimes involves the use of a slag to hold the oxidised Cu, but some Ag is also inevitably oxidised to the slag. The solubility of Ag in sodium silicate slags at 1 100 and 1 150 degrees C has now been determined over a very wide range of oxygen partial pressures. Silver was found to be present in the slags both as neutral atoms and as AgO(0.5). The activity coefficient for atomic Ag was a very strong function of slag composition and temperature, whereas that for AgO(0.5) was much less affected by slag composition and was almost independent of temperature over the limited range examined. The results reveal that the dissolved Ag cannot be fully recovered by reduction of the slag with very reducing gases

Jun 21, 1905

By E. L. Singleton

The Bureau of Mines investigated extraction of aluminum from aluminum-silicon alloys as a means of utilizing domestic aluminum silicate ores for aluminum production. Aluminum was extracted from aluminum-silicon alloys by electrolysis in molten electrolytes of NaCl-KCI-AIC13 and NaCl-KCI-AIF3 in a laboratory-scale cell. Six alloys with aluminum contents ranging from 20 to 87 percent aluminum were tested, and aluminum products of primary grade or better were obtained. More than 80 percent of the aluminum was recovered with current efficiencies as high as 91 percent. Recovery of a metallurgical-grade silicon product from the anode residue by an acid leaching procedure was possible with the 50-50 and 65-35 Al-Si alloys.

Jan 1, 1972