Search Documents

By Patrick R. Stephenson

The Australasian Code for Reporting of Mineral Resources and Ore Reserves (the ?JORC Code?) has been operating successfully for 14 years, and has an ancestry dating back over 30 years. Together with complementary developments in stock exchange listing rules, the Code has brought about substantially improved standards of public reporting by Australasian mining and exploration companies. The Code is regarded as a world leader in its field, and has been used as a basis for the development of resource/reserve reporting standards in other countries. The reasons for its success are varied, foremost amongst them being its adoption in full by the Australian and New Zealand Stock Exchanges, and the ability and willingness of mining industry organisations to bring Competent Persons to account when necessary. The latest revision of the JORC Code was undertaken in 2002/03, based in part on releases of upgraded reporting standards in Canada, United Kingdom/Western Europe and South Africa, and the 2003 edition is expected to be released mid-year. Two of the more significant changes are: the introduction of a requirement for a Competent Person to be responsible for the documentation upon which Exploration Results are reported; and inclusion in the definition of a Competent Person of a reference to ?Recognised Overseas Professional Organisations?, being overseas professional organisations to which Competent Persons may belong for the purpose of preparing documentation for the submission of reports to the Australian Stock Exchange.

May 1, 2003

By Ian S. Ross

The emphasis in this paper is focussed on dry bulk car go or the same cargo converted to slurry form for ease of handling. It is this type of cargo which is of primary interest to the mining industry whose products it represents to a large extent. The design problems associated with the handling of liquid bulk and of unitized cargo are sufficiently different to be treated separately. This paper then will consider the port handling facilities of dry bulk commodities as part of a system consisting of (1) the movement of products to the port area, (2) the movement of products out of the port area and (3) the handling of products within the port area itself. Expanding within these three components of the total transportation system, the paper will discuss the various difficulties encountered concerning the mode of transport into the port area and the method of handling product from transport to stockpile. Secondly, and before discussing the port area itself and in order to complete the conditions under which the port must operate, the movement of products out of the port area will be covered dealing with such items as the accommodation of the ship, problem associated with the very large ships, optimum berthing arrangements and the need to consider the various costs associated with the vessel. Finally the paper will review within the port or interface area such items as stockpiles, method of recovery, inventory control and an outline of the common design difficulties encountered. In all cases the relative influence on the total transportation costs of each of these dry bulk transportation system components will be considered.

Jan 1, 1972

The Anglo Platinum Mogalakwena North concentrator was one of the first three hard rock mineral processing applications to utilise a HPGR circuit in preference to a SAG milling circuit. This was driven by the extreme competence of the ore that had given rise to throughput issues on the original South Plant. Despite more than adequate capacity and performance of the individual comminution units, the circuit has struggled to obtain full design capacity. A thorough review of the integrated performance of the circuit revealed a wide range of bottlenecks and underutilised parts of the circuit arising from design issues. Interestingly, the major opportunities lie in materials handling issues and mismatch of loads about the circuit. This paper presents the high-level outcomes and the associated opportunities, and is pertinent to all HPGR circuit designs.

Jan 1, 2012

By H. C. Morehead

The United States Cement, along with other industries, is being devastated by an unprecedented penetration of domestic markets by imported products. The overriding questions are: 1. Have foreign manufacturers improved their processes to an extent they can outperform U.S. producers in their home markets? 2. Is it gross inefficiency on the part of the U.S. producers that is allowing foreign producers to be capable of replacing a local U.S. producer in his normal home market? 3. Is there a combination of the first two questions that economically justifies this type of market overrun? The answer is a simple NO!. In a fair trade market atmosphere, U.S. producers are definitely competitive.

Jan 1, 1985

By Serge Rudchenko

A study to determine the potential use of retaining structures in open pit backfilling. Research and review of the open pit mine environment, mine waste disposal, and past and current use of retaining structures. A development of specific structures, the culvert/ tunnel concept, and an anchor block retaining concept. The cost benefit of retaining structures used for in-pit backfilled waste.

Jan 1, 1981

By W. Dan Walker

In an effort to keep mine hoist accidents to a minimum and to impart to managers and workers the essential elements that enter into safe installation and maintenance of hoisting equipment, the Bureau of Mines presents this Information Circular as a guide. Hoisting of men and materials is an essential operation in many mines and has become so commonplace that some persons are likely to ignore day-to-day inspections or become lax in the operating phases. With proper maintenance and operation, hoists can be exceptionally safe. However, lack of strict attention can invite tragedy or costly shutdowns.

Jan 1, 1961

By By the staff of Gold Fields of South Africa

A diamond-drilling programme conducted from 1971 to 1973 by the Phelps Dodge Corporation revealed three complex sulphide ore-bodies in the highly folded Namaqualand mobile belt on the farm Aggeneys, some 65 km west of the small town of Pofadder on the road to Springbok in the northwestern Cape. Of these, the Broken Hill occurrence is the most promising.

Jan 1, 1980

By van der Walt TJ, van Deventer JSJ, Reuter MA

Owing to their complexity, many metallurgical processes are difficult to model fundamentally, and as a result more attention has been focused on the use of artificial intelligence techniques to simulate these processes. In this paper recent advances in the use of neural nets to model processes not amenable to conventional methods are discussed. These include the application of a new modelling methodology based on the use of neural nets for the dynamic simulation of metallurgical processes, the use of conventional techniques in conjunction with neural nets to simulate gravity separation circuits, as well as the detection of gross errors in variable measurements by means of a neural net representation of the relation between measurement and constraint residuals.

Jan 1, 1993

By H. J. Struth

AN unusual engineering achievement in the Gulf Coast last year was the drilling of a wildcat well in the swamps of Louisiana, using direct current. More unusual was the fact that it was necessary to house a diesel engine and generator on a barge in order to supply power. The remoteness of the well made it necessary to transport living quarters and drilling equipment to the location by means of barges, and involved the digging of a canal from a lake to the location, approximated one mile. The drilling equipment used on this well consisted of two generating units, each having one 210-hp. six-cylinder @$-in. bore type VDMA, 600 r.p.m. diesel engine, direct connected to a type CD-169, 125-kw., 250-volt direct current generator, which in turn is direct connected to a type CD-105, 15-kw. 250-volt exciter. One of these motors operates the draw works, one the mud pump, and one a duplicate spare. The generating equipment on the barge was approximately 250 ft. from the derrick, the control wires being brought from the derrick to the generator barge enclosed in a standard fire hose. This is an original idea for confining the con- 11.01 wires in one cable; obtaining minimum space and ample protection. Both control and power lines were suspended on poles. This well was at Lake Grande Ecaille Dome, which was located by seismograph in 1928. Fig. 1 shows the derrick, power barge and living quarters where direct G. E. current was used with rotary drilling equipment.

Jan 1, 1932

By Jason Swartz, Gerardo Gomez, Henry Leighton

San Antonio has experienced sustained growth for decades, putting increased pressure on existing wastewater infrastructure. In June 2013, San Antonio Water System (SAWS) reached a Consent Decree agreement that requires significant improvements to the wastewater system over a 10-year period to reduce Sanitary Sewer Overflows. One of the critical projects was the W-6 Upper Segment Tunnel project to reduce sanitary sewer overflows on an existing sewer main running through Lackland Airforce Base. The replacement project consisted of a new tunnel nearly 29,000 LF of primarily 104" FRP. The project also includes nine shafts and multiple trenchless crossings to make near surface connections to the new works.

Jun 23, 2024

By Jorge Madias

Neste trabalho se leva a cabo uma revisão da literatura sobre defeitos em beam blanks. O foco é no mecanismo de formação e as soluções propostas para diminuir sua ocorrência. Os defeitos superficiais incluidos são as trincas longitudinais e transversais, bleeding, pinholes e escória. Os defeitos internos levados em conta são os blowholes, as trincas centrais e as trincas nas pontas das abas. A revisão incluie as técnicas utilizadas para pesquisar os defeitos: caracterização metalográfica, CFD, modelagem termodinâmica e termomecânica, etc. As medidas adotadas estãorelacionadas a mudanças no sistema de lingotamento (por exemplo o design da vâlvula submersa), design do molde, mudanças e regulação do resfriamento secundário, suporte dos veios.

Oct 30, 2017

By H. Reginald Hardy

This report describes the results of a research project carried out to investigate the feasibility of using transducer arrays, located on surface or in shallow boreholes, above an active coal mine to detect and locate the source of underground microseismic activity which normally occurs during mining. The initial stage of the project involves the design and development of a self-contained mobile microseismic monitoring facility capable of use in remote field locations. Following this a variety of transducers, and transducer field installation techniques were investigated to obtain optimum sensitivity and high signal-to-noise characteristics. Preliminary efforts were also undertaken to develop semi-automated techniques for analysis of microseismic field data. Using the facilities and techniques developed field studies were carried out at a number of surface locations over a central Pennsylvania coal mine operating at depths of the order of 500 feet. In particular studies were con-ducted over a previously mined development area, troubled by extensive problems of roof instability, and over two longwall panels during mining. Although many of the field studies were carried out during the development stage of the project, results in general have been most encouraging. Limited results were obtained over the development area, however excellent microseismic signals, correlating with underground strata instability, were detected over both long-wall areas, proving the general feasibility of surface monitoring techniques. More recent studies, carried out as part of a subsequent project, and utilizing modified geophone installation techniques at a third longwall site, have verified explicitly the feasibility of measuring underground microseismic activity from surface locations. Sections of typical field data are included in this report along with a brief review of the studies carried out at each of the field sites. Detailed analysis of data obtained at the second and third longwall test sites will be presented in a later report.

Jan 1, 1974

By Clyde E. Williams, V. N. Krivobok, C. H. Herty

THE extreme effect of the depression on the steel industry is well illustrated by the fact that the amount of iron ore shipped from the Lake Superior district was the lowest in 47 years. Something over 3 1/2 million tons of ore was shipped in 1932, compared with over 65 million tons in 1929. It is not surprising then that practically no advancement in iron ore beneficiation has been made. Improved research and development work, however, was continued at the Michigan College of Mines in the survey of the lean iron ores of Michigan with reference to the possibility of their concentration; at the University of Minnesota in its large-scale jigging studies of Lake :Superior ores; and at Battelle Memorial Institute in the development of improved jigging of iron ores. The successful operation of the new Hadsel mill at a gold property in California gave such low grinding costs on a quartz ore as to give much encouragement in the iron ore industry for a cheapening of the cost of grinding lean ores for concentration.

Jan 1, 1933

By Harry R. Nicholls

A simple economical method has been developed for determining the in situ longitudinal and shear velocities in rock from which its elastic constants can be calculated. By detonating small charges of high explosives in shallow drill holes near a free surface, both longitudinal and shear waves were generated simultaneously. Accelerometers and velocity gages mounted to the rock surface were used to record the arrival time for both waves over travel path lengths from 50 to 450 feet, Measurements were made in two rock types. From the arrival time measurements, the longitudinal and shear wave velocities were calculated. From these velocities and the density of the rock, the elastic constants were calculated. The dynamic elastic constants of drill core samples of the two rock types were determined in the laboratory by the resonant-frequency method, The lab- oratory and in situ elastic constants are compared and significant differences noted. In general, there is less spread in the in situ data than in the laboratory data, and Poisson's ratio does not fall outside the theoretical limits for the in situ data as is often the case for laboratory-determined elastic constants.

Jan 1, 1961

By L. J. E. Hofer

THIS BULLETIN analyzes and summarizes research at the Bureau of Mines dealing with the preparation, properties, and reactions of iron carbides in the period 1948-60, part of which was sponsored by Wright Air Development Laboratories. The objective was to develop better catalysts for the synthesis of methane and higher hydrocarbons from hydrogen and carbon monoxide. The investigations resulted in the first adequate characterization of epsilon iron carbide, which later proved to be an important intermediate in the tempering of martensite in steel. At temperatures near 170° C, the carbon in carbon monoxide reacts nearly quantitatively with finely divided alpha iron to form an iron carbide in which the metal atoms occupy the positions of the close packed hexagonal arrangement with lattice parameters of ao=2.754 A and co=4.349 A. The carbide has a composition within 2 atomic percent of that required for the formula Fe2C, a Curie point of about 370° C, a specific magnetization of 160.4 ergs per gauss-gram Fe at 50° C, and a ferromagnetic moment of 1.70 Bohr magnetons. Epsilon iron carbide can be converted to chi iron carbide by thermal treatment at 343° C for about 70 hours. The chi iron carbide so formed has a Curie point of 247° C, a specific magnetization of 142.5 ergs per gauss-gram Fe at 50° C, a ferromagnetic moment of 1.72 Bohr magnetons per iron atom, and a paramagnetic moment of 5.5 Bohr rnagnetons per iron atom. Direct synthesis of this carbide from carbon monoxide at 240° C indicates a composition within 7 atomic percent of that required for Fe2C. Chi iron carbide can be converted to cementite at 550° C in about 315 minutes. The theta iron carbide so prepared has a Curie point of 210° C, a specific magnetization of 147.3 ergs per gauss gram Fe at 50° C, a ferromagnetic moment of 1.72 Bohr magnetons per iron atom, and a paramagnetic moment of 3.9 Bohr magnetons per iron atom. Pure chi iron carbide reacts to form theta iron carbide by the elimination of free carbon. In the presence of an excess of free iron in intimate contact with the carbide, chi iron carbide reacts with the free iron to form theta iron carbide. The second reaction proceeds at an appreciable rate at 320° C and can be used to snythesize finely divided theta iron carbide with no free-carbon impurity at low temperatures. The ease of the reaction in the presence of free iron suggests that chi iron carbide is an intermediate in the tempering of epsilon iron carbide to theta iron carbide as it proceeds in steels. Experiments on carbon steel show that the magnetic moment of the iron atoms in martensite is about 2.2 Bohr magnetons per atom, a value approximately the same as that of the iron atoms in alpha iron. The Curie points of epsilon iron carbide, chi iron carbide, and theta iron carbide were found -in various specimens of tempered steel to be 10° to 20° C lower than normal values. This shift is probably the result of manganese in solid solution. Preparations of various compositions of epsilon iron carbonitrides show many effects of extensive isomorphism between epsilon iron carbide and epsilon iron nitride. The action of carbon monoxide on finely divided alpha iron at 400° C results in free carbon deposits containing filaments about 0.1 micron in diameter and several times as long. The filaments are characterized by nuclei of dense material located midway from each end of the filament. Although carbiding to near completion at 240° C over periods of about 300 hours produces a preparation containing no appreciable percentage of epsilon iron carbide, very brief periods of carbiding of the order of a minute result in the formation of detectable epsilon iron carbide even at temperatures as high as 325° C. The data indicate that epsilon iron carbide is an intermediate in the formation of chi iron carbide during its formation from carbon monoxide in the gas phase. Attempts to convert cementite to chi iron carbide by cold work increased the Curie point but did not change the X-ray powder diffraction pattern.

Jan 1, 1966

By Z. Jun, L. Kerning

Jinlong copper smelter and refinery, originally designed for 100,000tpa primary copper and started up in 1997, has been expanding its capacity on the basis of operational optimization and by modifying its facilities. Currently it is producing 210,000tpa primary copper, and the new phase of expansion project with a target capacity of 350,000tpa primary copper is ongoing. This paper reviews problems and improvements made with operation and equipment in the past years. Recent plant operation is briefly described. The expansion projects completed are summarized and the ongoing expansion project is present.

Jan 1, 2007

By E. De Souza

The instrumentation and monitoring of rock behaviour have played an important and necessary role in the practice of potash, rocksalt, gypsum, trona and coal mining. The art of rock instrumentation applied to soft rock and coal mining has progressively evolved over the past years and will surely continue to advance at a faster pace in the future as a result of the technological revolution we experience today. The development of sophisticated mine-wide data communications systems is being used for instrumentation and sensor automation, and laser, sonar and geophysics technology are being continuously adapted for rock monitoring purposes. In this paper, the author provides an overview of typical rock instrumentation used today and offers some views of the progressive evolution in rock mechanics instrumentation sophistication and design.

Jan 1, 1998

By Jim Excell, Jim Rothwell, Mike Rylati

"LocationThe Ekati Diamond mine is located at Lac de Gras, Northwest Territories.Brief Description of OperationBHP Diamonds Inc. has developed Canada's first diamond mine in the Northwest Territories (NWT), Canada. BHP Diamonds Inc. is part of the BHP World Minerals Division ofBHP Minerals. The project is a joint venture between manager and operator BHP (51%) and the Blackwater Group (49%). The Blackwater Group comprises Dia Met Minerals Limited, Charles Fipke and Stewart Blusson.Production at the NWT diamonds project began in October with the mine officially opened October 14, 1998. The project is situated on an 853 000 acre claim block located in the Lac de Gras region of the NWT. It is about 300 km northeast of Yellowknife and 100 km south of the Arctic Circle. The seasonal winter ice road to the Echo Bay Lupin mine passes along the eastern margin of the project area. This allows road access each year from mid-January to mid-April. For the remainder of the year, the project is accessible only by air.HistoryIn 1980, Charles Fipke traced indicator minerals east from the Mackenzie River area. He discovered indicator minerals in the Lac de Gras area and staked mineral claims in 1989. A joint venture was formed between BHP and Dia Met in 1990, and in 1991, the first diamonds in the NWT were discovered at Point Lake by BHP and Dia Met. This initiated the largest staking rush in Canadian history. The joint venture launched an aggressive exploration program.Koala, Fox, and Leslie were identified in 1992 as potentially economic pipes.As soon as the project's potential was established, it was recognized that an enormous amount of work had to be completed in several areas before a mine could be developed, namely: technical evaluation of the resources; environmental and socio-economic evaluation to procure the necessary permits for the development; and engineering design to optimize mining and processing of the resource and to comply with specific environmental requirements."

Jan 1, 2000

By M. S. Moats, W. C. Hartzell

The stable domestic supply of gallium, indium, and germanium has been identified as a critical need for the United States. Electric arc furnace dusts, processed to recover zinc, produce a residue that could be a potential source of these critical materials. An industrial zinc leach residue was characterized to determine its particle size, chemical composition, and predominant mineral phases. Heated, atmospheric, agitated leaching using sulfuric acid and hydrochloric acid was examined to determine the extractions of gallium, indium, and germanium as a function of concentration and temperature. Extractions of gallium were found to be similar to iron in all experiments. The maximum percentage of Ga, Ge, and In leached into solution were 71%, 63%, and 48%, respectively.

Feb 1, 2023

By George L. Richert

The Minas de Matahambre is situated on the north coast of Cuba, in the Province of Pinar del Rio, approximately 150 miles west of Havana. This nine is the only producer of copper in Cuba, and has been worked for the past 15 years. In 1921 the property was affiliated with The American Metal Co., Ltd., and has been worked by them since that time under the direction of Mr. D. D. Homer, General Manager. Extracts from P. D. Wilson's ?Preliminary report on the geology at Minas de Matahambre? have been freely used in this report.

Jan 1, 1929