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The Broken Hill orebody ,occurs in the Willyama Complex, a block of Precambrian rocks which have been strongly folded and metamorphosed at moderate to high grade. Although -the origin of the silver-lead-zinc mineralization remains obscure, recent investigations have substantiated the view that the orebody has undergone concomitant high grade metamorphism with the enclosing wallrocks. The mesoscopic structures produced by this metamorphism are described, and the possible processes Telating to their formation are disoussed.In the high grade ore, metamorphic structures which can be recognized are foliation and lineation, wallrock fragments, layering, flow folds, ore breccias, and sulphide bearing veins. These structures can be related to processes involving plastic flow and fluid phase transport of the mineral assemblage. 'In areas of low grade mineralization adjacent to high grade ore, the structures more closely resemble those produced in -the wallrocks-foliatlon, lineation, layering, folds, and sulphide injections. Within areas of high grade ore, lenses and pods of manganese silicates Probably represent original inhomogeneities in the ore, i.e., portions of manganese-rich and sulphide deficient rock which have been metamorphosed to manganese silicates.From the structures displayed, a sequence of events has been established for the plastic flow of ore during deformation.

Jan 1, 1975

By M. Ramström

"In 2002, Atlas Copco Rock Drills AB released the new rig control system (RCS) technology for all of its drill rig types. RCS opened the way for a new generation of computerized drill rigs based on modern, standard PC-computer technology. Drilling accuracy, information logging, reduction in manpower in some types, and serviceability have all taken a quantum leap forward when compared with previous generations of drill rigs. RCS is modularized and distributed by means of CAN-bus technology. This technology, which is well proven in automobile applications, forms the communication backbone of the rig. The modularity facilitates almost unlimited possibilities for the expansion and adaptation of drill rig functions."

Jan 1, 2005

By R. S. Dean

[During t!~c past f isc.~l y~:-.r the Xetzllvz-gicd 3ivi oion has made im- portant contribution-, don,- tlie lines rlictnteil by the Bureau policy of con- servation of domestic rnker~l rcsoul-ces throui;h use. During t!~c past f isc.~l y~:-.r the Xetzllvz-gicd 3ivi oion has made im- portant contribution-, don,- tlie lines rlictnteil by the Bureau policy of con- servation of domestic rnker~l rcsoul-ces throui;h use.]

Jan 1, 1940

By R. S. Dean

[During the past fiscal year the Metallurgical Division has made important contributions along the lines dictated by the Bureau policy of conservation of domestic mineral resources through Its investigations include determining of fundamental data of metallurgically important materials improvement of standard ore-treatment method to eliminate waste and improve the grade or recovery of the products; and development o new metallurgical processes.]

Jan 1, 1940

By W L. Jennings

This paper summarises work undertaken to date as part of an investigation into the mineral resources of the proposedNorth West South Island National Park. The area covered by the proposed national park is underlain by many rock types that have undergone a long and complex history of evolution which has endowed it with some of the best potential for a wide range of different minerals in New Zealand. Many of these minerals occur only in this area or in Fiordland National Park.   The first gold-rush in the area occurred in 1856 and followed the discovery of payable gold at Lightbands Gully, south of Collingwood. The miners first focused on the alluvial deposits but soon shifted attention to lode potential. The total historical gold production for the area may be over 400 000 oz (NZ$250 - NZ$295.6 M at 1993 prices).   In addition to gold, a wide range of other minerals have been reported from the area including molybdenum, copper, nickel, zinc, silver, bismuth, stibnite, lead and antimony. The Onekaka iron-ore deposits have produced small tonnages of ochre and iron-ore at various times. Tungsten, platinoids and other metals have been. given only minor attention. The diverse geology of the Northwest Nelson has resulted in the occurrence of many industrial minerals which have been exploited in generally small-scale operations. Aggregate, chrysotile asbestos, clay, dolomite, marble, limestone, dimension stone, rip-rap, talc-magnesite and wollastonite have all been produced.

Jan 1, 1993

By Joan Weinberg

The economy continued to expand during the third quarter, as real GNP rose at a seasonally adjusted annual rate of 3.8%, up from 2.5% in the second quarter (table 1). Continued job gains (see below), higher incomes, and an increase in installment debt, resulted in a nearly 20% increase in consumer spending on durable goods. Consumer expenditure on nondurables fell slightly, while spending on services continued at a moderate pace. Nonresidential fixed investment climbed nearly 24%, as producers purchased more durable equipment. Residential fixed investment was adversely affected by rising interest rates, which slowed new home construction from January to August, 1987 to a rate 11.2% below a comparable period in 1986. Net exports of goods and services deteriorated slightly, after three consecutive quarters of improvement. The volume of net exports has risen 15% for the year, contributing to economic and employment growth, but large price increases on imports have slowed the improvement in the nominal trade balance. Although U.S. goods have declined in price relative to foreign goods because of the devaluation of the dollar, faster growth in exports is hampered by austerity programs in developing countries, and emphasis in Germany and Japan on curtailing inflation and fiscal deficits.

Jan 1, 1987

By William J. Douglas

This document describes the development of a conventional mining equipment data base, and an approach for conducting industrial engineering studies of arbitrary mining systems employing network techniques. Data was acquired through underground time studies. Each member of a four-man field team was assigned to a specific machine during each shift for which observations were conducted. Using digital wrist watches and networks describing the man-machine interactions, all events occurring luring the course of each shift were recorded on cassette tapes. The tapes were transcribed, coded, keypunched, and validated using computerized editing techniques. The resulting data files were processed to provide statistics relating to activity durations and event frequencies. The results were used to evaluate operator, machine, and system performance for each section which was observed. Equipment, reliability, and maintainability analyses were conducted using the industrial engineering data files in conjunction with historical information collected at the mine site.

Jan 1, 1976

By R. W. Bee

This project, sponsored by the U.S. Bureau of Mines, Division of Environment, addresses two major subjects: refuse removal and subsidence monitoring. The refuse removal task consisted of developing a methodology for selecting the most economical combinations of coal mine breaker refuse and rock banks, disposal sites and material moving systems (trucks, trains, belt conveyers and pipelines). To prepare plans for moving refuse in the Lackawanna Valley of Northeastern Pennsylvania, refuse banks were inventoried, underground disposal sites identified and unit cost data prepared for the various material moving systems. The subsidence monitoring task consisted of defining the phenomenon of coal mine induced surface subsidence, establishing operational requirements, cataloging sensors and techniques to detect and measure subsidence and testing of the most promising techniques (photoelastic patch, tiltmeter, strain gage, microseismic and precise surveying). A preliminary system for a 700 acre area in Scranton utilizing 267 grid sensors, seven microseismic sensors and precise surveying techniques was designed with initial and annual operating costs determined. Two minor tasks supported both main subjects: zoning in the Northern Anthracite Field of Pennsylvania and Technology Transfer of subsidence vulnerability prediction techniques.

Jan 1, 1972

By Y. Luo

"It is generally known that spontaneous combustion potential is a function of coal rank, with low-rank coals having high susceptibility to self-ignition and high-rank coals having low potential. To establish this functional relationship and use it as an engineering tool to identify the propensity of coal to self-heat, both rank and spontaneous combustion potential should be quantified. ASTM D388 is normally used to classify coals by rank, but this classification system can only serve a qualitative analysis. To classify coals by their potential for spontaneous combustion, the self-heating temperature (SHT) method originally developed by the U.S. Bureau of Mines (USBM) was used by Litton and Page (1994) to correlate coal rank with spontaneous combustion potential. In that method, the SHTs of coal determined by an adiabatic experiment are linked with proximate analysis results through a proposed concept known as the “moist fuel ratio.” This ratio is a function of moisture, volatile matter and fixed carbon, all of which have widely different content percentages in different ranks of coal and have strong relationships with coal rank. However, the method is highly empirical, and there is large standard deviation between experimental data and calculated results. The equation correlating the coal quality parameters to determine SHT should be improved with more experimental data.This paper reports on the development of a new system for predicting the spontaneous combustion potential of U.S. coals, based on coal composition data from the U.S. Geological Survey’s coal quality database. First, the user is provided with a quantified classification of coal rank. Second, based on experimental SHT data covering a wide range of ranks from lignite to low-volatile bituminous coal, the original USBM correlation for predicting SHT is improved for the respective rank of coal. The relationship between the rank and SHT of U.S. coals was developed and plotted. The plot diagram can be used for a quick estimate of the SHT of a U.S. coal and as a cost-effective tool for the initial risk assessment of a new mine development."

Jan 1, 2015

By Robert C. Weisner

Current production costs and market conditions in the potash industry of the Carlsbad area were studied to determine the potential values of the potash mineral resource that would be lost or foregone if the Waste Isolation Pilot Plant (WIPP) facility is constructed on the proposed site in that area. The purpose of the WIPP project is to investigate the possibility of developing a nuclear waste disposal plant in the salt formations at the site. Analyses were made of all potash deposits determined to be in the site. Mining and processing under the most favorable recovery systems were considered. Value determinations were based upon estimated operating and capital costs of current mine-mill operations in the Carlsbad area. This study was made for the Energy Research and Development Administration (ERDA) by members of the Federal Bureau of Mines Minerals Availability System staff.

Jan 1, 1979

By Clarence Karr

AN EXTENSIVE characterization was conducted on the neutral oil components in a low-temperature bituminous coal tar. A total of tai individual compounds identified with respect to individual isomers, and at least 55 other compounds were indicated to be present. The amounts were determined in all instances. A comparison of isomeric distribution in the tar with thermo-dynamic equilibrium distribution, and kinetic distributions indicated that the composition of the tar largely reflected the structure of the coal from which it was formed. Detailed descriptions are presented for the separatory and qualitative and quantitative procedures for the characterization of the neutral oil component. These include micro fractional vacuum distillation, displacement liquid chromatography, gas-liquid chromatography, countercurrent distribution, and infrared and ultraviolet spectrophotometry. Descriptions are given for the synthesis of authentic specimens of alkylindenes, The ultraviolet and infrared spectra of 134 polycyclic compounds, ranging from alkylindenes to alkylphenanthrenes, either found in the distillable neutral oil, or thought likely to be present, are also given.

Jan 1, 1967

By K. T. Audt

The Yayoi period, from about 300 B.C. to A.O. 300, represents a time of important changes in Japanese history. During this period the advanced rice culture of the Asian continent was introduced to Japan, along with the techniques of animal husbandry, spinning, bronze casting and metal working(1) . As was the case in the Jomon period (11000 B.C. to 300 B.C.), the Yayoi period is traditionally defined by a particular type of pottery, characterized by the use of the potter's wheel and an extreme simplicity of decoration and form(2) . Pieces of this pottery were found in 1884 in a district of Tokyo, known as Yayoi-Cho, not far from Tokyo University. Within a decade the name Yayoi had come to be used for the period which also saw the first casting of metals in Japan121. During the Yayoi period, the foundation of the ancient Japanese state was laid as the individual small communities were unified and as labour specialization and social levels developed. In fact, the Yayoi may be the true ancestral culture of Japan(3) . However, the origin of the Yayoi is not definitely known. One theory indicates that the Yayoi people may have been driven from the Asian mainland (via Korea) by the dynastic wars that accompanied the unification of China under the Ch'in and Han and that these settlers rapidly displaced the Jomon. Bronze objects and the cultivation of rice may have arrived about the same time - in the third century B.C. Iron was in Japan within another century, but since it rusts badly and disintegrates, only a few small pieces are known from such an early date(4) . After about 50 B.C., the Yayoi cultures of western Japan were in fairly close and regular contact with the continent via Korea(5)

Jan 1, 1999

By K. C. Dean

During the course of the investigation of manganese mineral occurrences in the western United States, the Bureau of Mines collected several lots of ore' from properties in the vicinity of Winkelman, Ariz. As none of the ores would be marketable directly, an investigation was made to determine their amenability to concentration by ore dressing. The Geronimo group of claims is in Pinal County, 8 miles west of Winkelman, Ariz. The manganese oxides occur as cementing material in ore zones of conglomerate. Representative samples of a 2-ton lot of ore cut from outcrops of two lenticular deposits were laboratory-tested. Two 1-ton samples from the Benningfield property were similar in physical characteristics but differed in grade. This claim is 11-1/2 miles south of Winkelman and about 1 mile west of the San Pedro River on the south side of Putman, Wash. The manganese minerals occurred as nodules and lenses, replacing limestone, in a capping over a dark, igneous dike. The North Star group consists of five claims on the west side of the San Pedro River 14 miles south of Winkelman. The ore consists of a low-grade, manganese oxide-calcite occurrence interspersed with stringers of higher-grade material and is present as filling in a fissure zone in porphyry. Two samples were obtained by the examining engineer; one sample represented run-of-mine material, the other represented ore from the vein that could be hand-sorted or selectively mined.

Jan 1, 1952

By Eduardo Simian

El presente texto señala las condiciones adecuadas de las inversiones respecto al cobre en Chile. Así también se define las cinco materias que definen la política del Gobierno para el desarrollo de la industria cuprífera chilena como la idea de refinación, franquicias y garantías de las inversiones, intervención en el comercio, adquisiciones en el país y las sociedades mixtas.

Nov 1, 1965

By Nei Bongiorni Alff de Freitas

O uso de velocidade de onda sônica tem ganhado espaço na estimativa de resistência à compressão uniaxial (UCS) por ser um método mais barato, rápido e não destrutivo em comparação com o método tradicional. No entanto, por ser uma correlação empírica, as equações de correlação geradas variam muito quanto a precisão e necessitam serem aferidas para cada nova localidade geológica estudada. Com o objetivo de alcançar correlações mais precisas, esse artigo utiliza um maior critério de seleção das amostras. Arenitos e conglomerados criteriosamente selecionados resultaram em uma forte correlação com R2=0,99. Dessa forma, se constatou que quanto mais específica for a litologia selecionada, melhor é a correlação obtida.

Oct 30, 2017

By Lu Peiyan

A computation model of soil-pile (wall) interaction under lateral loading is presented in this paper. The model has been applied to some engineering projects, and the comparison between computation result and measured result shows good agreement, so the model is proved to be correct and practical.

Jan 1, 1991

By Juan Mendoza F.

Diversas minas utilizan programas computarizados para resolver obstáculos presentados en las operaciones y así planificar mejor la producción de las mismas. En este sentido, el objetivo del texto señala la aplicación del modelo matemático como herramienta que establece datos a través de un programa de minado óptimo mensual y controla la producción de la mina. El modelo está diseñado para la instalación Data General, modelo eclipse en lenguaje FORTRAM IV y conlleva el proceso de cuatro etapas: control de leyes de producción, control de recursos, control de costos de minado y plan de minado óptimo.

Nov 8, 1982

By Carlos E. Bardález Hoyos

El presente trabajo describe las funciones del ingeniero industrial y su relación con la productividad de la industria minero metalúrgica. Para ello, refiere el concepto de ingeniería industrial y su organización personal e interna y se muestra la conveniencia de contar con un Departamento de Ingenieria Industrial en una empresa minera.

Nov 20, 1978

By R. B. Alke

Request to Mine Beneath Bridge The Jabs Run Bridge is a reinforced portland concrete arch filled bridge located on WV Bouts 7 near Pentress, WV. The bridge has a span of 22.9 m (meters) and a height of 4 m above normal pool elevation to the underside of the center of the arch (See Pig 1). The bridge is a two lane structure with a width of 6.86 m. The structure is over 50 years old Wing been built in 1929 and is owned by the Department (WV Department of Highways).

Jan 1, 1984

THE furnace described in this paper was installed and has been used by the writer for the melting of rich gold-bearing material, and has given complete satisfaction. It may, therefore, prove of interest to other metallurgists who are faced with a similarproblem. A furnace of this type should be most suitable for the reduction of "cyanide preeipitate," "charcoal ash," "anode sludge," &c. formerly the melting was done in fire-clay crucibles, using coke or crude oil as fuel, but this method is costly, slow, and unsatisfactory. A small water-jacketed blastfurnace was also tried on this material after briquetting it, but was discarded in favour of the electric furnace. The furnace may be described as a simple form of the Heroult resistance furnace, with an adjustable upper electrode and a fixed bottom electrode. This is in accordanee with Stansfield's classification of electric furnaces. The heating is mostly due to the resistance offered the current by the molten slag. The melting chamber consists of a steel drum 14 in. in diameter and 21 in. high, and is lined with silica bricks specially made to fit the shell. The internal diameter is G in. The bricks contain 92 % silica, are made from calcined quartzite bonded with fireclay, and are similar in composition to those used for lining steel converters. They are set in a mixture of finely-ground quartzite and clay, and well dried out. The shell is bolted to a steel plate, which forms the decking of a truck running on rails, so that the furnace can be moved under ahood for carrying off the fumes. A cast-iron slag spout is bolted to the shell below the tapping hole, which is 4 in. from the bottom of the shell. Opposite this another hole 1 in. in diameter is drilled through the shell and lining for the passage of the lower...

Jan 1, 1918