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By Earle Schumacher

THE solidus line above the solid solution field in the lead-antimony system was originally determined by Dean and his associates1 from heating curves. They did not regard this line as having been accurately fixed and in their more recent publications2 the curves drawn do not follow closely the original data. The precise location of the solidus line is of importance in the extrusion of lead-antimony cable sheath, as the temperature of the metal in this process must be less than the lowest temperature at which any part of the alloy in the lead-press charge becomes liquid. It is very desirable, however, to operate at as high a temperature as possible, as the rate of extrusion for a given pressure is approximately doubled for an increase of 10° C. in temperature. The precise location of this line is also important, in the investigation of ternary systems of lead, antimony and a third metal. For these reasons, and because of the differences reported in the literature, data were secured on the lead-antimony solidus line by the classical quenching-test procedure.

Jan 1, 1927

By R. H. Atkinson, R. N. Rhoda

An improved technique has been developed for the deoxidation of palladium with aluminum which is especially suitable for use in making small castings with an induction-melting and casting machine. The effect of various crucible linings on the efficiency of the residual deoxidizer and accompanying oxide film in protecting palladium against oxidation during remelting also has been examined; the preferred crucible lining consists of zirconia cement. THE objective of this work was to develop a simple method of deoxidizing induction-melted palladium which would be suitable for use by manufacturers of jewelry and other small castings. In a common method of deoxidizing torch-melted palladium a piece of aluminum foil is dropped on the surface of the molten metal. If a film is present, which is usually the case, it must first be removed by oxidizing the molten metal thoroughly because it would interfere with the entry of the aluminum into the melt. Removal of the film is probably facilitated by a mild fluxing action of the silica crucibles which are used for torch-melting. However, removal of an alumina film from molten palladium in the crucibles normally used for induction melting is a much slower process and it became necessary to modify the de-oxidation procedure. In the modified procedure the charge is simply melted and the desired amount of aluminum, crimped to one end of a tungsten wire, is plunged through the film into the palladium and the wire immediately withdrawn. The trace of tungsten which dissolves along with the aluminum can be avoided, if considered objectionable, by using a palladium wire. In view of the persistence of the alumina film under the conditions of induction-melting it also was decided to ascertain the efficiency of this film in protecting palladium against oxidation during repeated remelting and casting. Melting Equipment and Materials The equipment used for melting and casting consisted of an Ecco GC:6, 6 to 8-kva high-frequency converter and an Ecco M34B centrifugal casting machine. This unit is being increasingly used for making jewelry and dental castings and it also has been found useful in making exploratory melts of a variety of nickel alloys, for which purpose it is well suited on account of its speed of melting and economy of material. A description of the machine and its operation will be published elsewhere.' A common palladium jewelry alloy, 95.5 palladi-um-4.5 ruthenium (referred to as "palladium" in the trade), was selected for the deoxidation tests. It was available as melting stock which had been melted in air to free it from oxidizable impurities, and also as clean scrap from previous melts which had been deoxidized with aluminum. The latter was thought to be typical of clean "palladium" scrap to be found in a manufacturing jeweler's establishment and it is also similar to one brand of "casting palladium." By the same token, the oxidized melting stock corresponds to "casting palladium" after the latter has been melted and thoroughly oxidized: Pure aluminum wire (99.9 pet), 0.032 in. diam; 1 in. = 0.036 g. Scrap tungsten wire, 0.014 to 0.020 in. diam. Argon, commercial water-pumped; 99.9 pet pure Experimental Procedure Samples of about 50 to 75 g of the palladium alloy were melted in a crucible lined with a proprietary refractory alumina cement. Some charges were melted in air, others in argon. The oxidized melting stock was melted and solidified a number of times in order to remove as much oxygen as possible before deoxidizing, but this treatment was unnecessary in the case of scrap. In either case the metal was deoxidized with aluminum (0.01 to 0.05 pet) by the

Jan 1, 1959

By K. Tabra

In a mine operation, the proper strategy to handle residues is one of the main concerns, in particular when dealing with mine/plant liquid effluents. Most active water treatment systems at metal mines rely on standard alkali-addition procedures. However, the increase of mineral prices, stricter environmental standards and high metal content in some effluents, has led to the development of alternative treatment techniques for their removal and/or recovery. This article presents a roadmap to face mine wastewater treatment requirement, with focus on two active treatment strategies: 1) conventional lime-based technology and 2) the use of NaSH or Fe(OH)3 for metal precipitation and separation, including possible valuable elements recovery. The Roadmap consists of 1) Approach to effluent treatment 2) Characterization 3) Precipitation tests 4) Solid/liquid separation tests and 5) Economic analysis.

Feb 27, 2013

By G. L. Smith

The fundamental challenge facing mineral and metal companies is how to create sustainable value while operating within mandated strategic bounds, identified constraints, and variable market and economic conditions. This can be achieved by allowing the fixed physical nature of the mineral asset to drive definition of the optimal technical solution to mining and processing activities, and developing and resourcing a strategically aligned portfolio of production entities that creates flexibility to near- and longer-term business environment shifts, i.e. a production mix that allows variation of output to respond to short term market variation, within a long term context. The practical achievement of this outcome is enabled by the concept of strategic long term planning. The core elements of strategic long term planning in the metals and minerals industry, and the relationship between them, are expanded. The strategic long term planning framework is a logic construct that enables delivery of an optimized, strategically-aligned business plan from the mineral asset portfolio using a set of tools and techniques with a common language, standards, systems and processes to align decisions and actions on a cyclical basis.

Jan 1, 2012

By Joseph J. Zaluski, J. Steven Gardner, Marco M. Rajkovich

The telephone rings at 3:20 a.m. An exasperated voice on the other end says, “There has been a mine explosion at Mine No. 5 and we have not heard from three units of men.” Twenty-three minutes later, the phone rings again and another panicked voice says, “There is something wrong at the slurry impoundment, the pool level has just dropped five feet and we are trying to figure out what is wrong” Thirty minutes later, the mobile phone rings. An excited security guard says, “We have reports of thick black water running down the right fork and left fork of Straight Creek and both seem to be rising in the banks.” If this is not enough excitement, the mobile phone rings again. A stressed company official says, “I just heard a report that black slurry is running out of the portals of XYZ Co. No. 2 Mine, which is adjacent to our No. 5 Mine.” Is this all some kind of dream or nightmare? More importantly, though, if this happens, what do you do? Most people think: “It can’t happen to me.” But mine explosions do happen, slurry impoundments can rupture and creeks can flood with black water causing damage to others, including competitors. A mine’s response must be quick, cool-headed, calculated and effective. This article examines the issues, concerns and ramifications of this hypothetical disaster. The authors then present a systematic crisis-management response.

Jan 1, 2004

By P. den Hoed, R. I. Rambiyana

"Four sulphide minerals - pyrite (FeS2), pyrrhotite (Fe1-xS), pentlandite ([Ni,Fe]9S8), and chalcopyrite (CuFeS2) - contain the base metals and most of the iron in concentrates of platinum group metals (PGMs). In the pyrometallurgical processing of PGM concentrates these sulphides form a matte during smelting, and iron and sulphur are removed from the matte during the converting process. This paper discusses the roasting of Merensky concentrate in air before smelting, with the purpose of reducing the matte load to the converter.Roasting tests were conducted in a bench-scale rotary kiln at temperatures from 350°C to 700°C. The concentrate tested contained 17.4% sulphur and consisted of 23% pyrrhotite, 16% pentlandite, 11% chalcopyrite, and 2% pyrite. The particles were fine (d50 = 22 µm), and all the sulphide particles were liberated. Roasting in air at 550°C and 650°C for 20 minutes removed respectively 60% and 70% of the sulphur. The iron in the sulphides was oxidized to Fe3O4 (magnetite) at temperatures below 500°C and to Fe2O3 (haematite) at temperatures above 550°C. At 700°C the bed sintered and copper oxides formed. At temperatures below 450°C oxidation was incomplete: pyrrhotite remained and only 30% of the sulphur was removed. Smelting tests were conducted to assess matte fall and the deportment of copper and nickel to matte. It was evident that roasting resulted in lower matte falls (a drop of approximately 60%) compared with matte falls from unroasted concentrate. The iron and sulphur levels in the matte were reduced to below 3.5% and 22% respectively.This paper also briefly describes the mechanisms by which pyrrhotite, chalcopyrite, and pentlandite are oxidized during roasting. For chalcopyrite, the mechanism proceeds through an intermediate solid solution phase, which extends from Cu1.02Fe1.04S2 to Cu2.04Fe0.72S2 to a copper-rich solid solution of bornite (Cu4Fe1.4S4-Cu2S). The oxidation of pentlandite proceeds through a monosulphide solid solution (Ni0.39Fe0.53S-Ni0.74Fe0.15S) to a solid solution of heazlewoodite ([Ni,Fe]3}xS2). These mechanisms are explored in relation to chemical thermodynamics and microstructures."

Jan 1, 2015

By J D. St George

In this paper a laboratory investigation into the effect of confining stress, water content and gas desorption on coal permeability is presented. Of major significance is the effect of coal permeability on outburst occurrence and methane production, which is influenced by changes in stress. Test results indicated that the shrinkage of the coal matrix associated with desorption is greater than the coal matrix compressibility which will cause a reduction in the effective stress, hence increasing coal permeability.

Jan 1, 1998

Jan 1, 2007

By E. C. Perkins

As part of a program for developing methods of using domestic titanium deposits, the Bureau of Mines investigated methods for chlorinating titanium slags prepared from titaniferous minerals by electrosmelting. Titaniferous slags were made from ilmenites in the following deposits: Valley County, Idaho; Trail Ridge, Fla.; Aiken, S. C.; and Maclntyre, N. Y.; titaniferous magnetite from Iron Mountain, Wyo., were also evaluated. The tests were made in two chlorinators, a 4-inch and a 36-inch unit. Preliminary testing was done in a 40-millimeter bench-type unit. Chlorine gas was contacted with a loose mixture of titaniferous slag and carbon at a high temperature to form titanium tetrachloride. The moving-bed system used in this work involved a downward movement of feed countercurrent to the chlorine flow, and residues continuously removed from the bottom of the reactor. The performance characteristics of these slags depended on their composition, which varied widely according to the geographic source of the ore. The results showed that all but two of the slags could be chlorinated as effectively as rutile, converting 70 to 80 percent of the titanium to the tetra-, chloride. The two slags that proved difficult were made from New York ilmenite and Wyoming titaniferous magnetite. These slags contained enough magnesium to cause clinkering, which necessitated that the bed be prematurely withdrawn before more than 70 percent of it could react. The iron content of the slags did not interfere with operating the chlorinators. The data from the 4-inch and the 36-inch units were in agreement on the relative amenability of the slags to chlorination.

Jan 1, 1962

By Lam. E. K., J. W. Jarvi, B. P. Bharadwaj

"The Rabbit Lake Operation is located in Northern Saskatchewan on the western shore of Wollaston Lake approximately 800 km north of Saskatoon, Saskatchewan.The Operation is owned by a joint venture of Cameco Corporation and Uranerz Exploration and Mining Limited. Cameco is the operator.The Mill started production in June 1975 under the ownership of Gulf Minerals Canada Limited and over the past twenty years has increased the rated production capacity to over twice the original design.The Mill was originally designed to process 485,000 tonnes per year of ore with an annual production of 2.0 million kg of U308 (yellowcake). During the past ten years changes in ore sources and process modifications have led to increased milling capacity and production targets. The Mill has treated a total of 8.6 million tonnes of ore and produced over 40 million kg of U308 in the twenty year period, despite the shutdown and cutbacks in operating time since 1989.The 1995 tonnage throughput was 206,000 tonnes per year. Annual production though has risen to 3.6 million kg of yellowcake despite the departure from full-time to half-time operation in 1991 (7 up-7 down). The forecast for the coming years will see tonnage rising from 300,000 to 570,000 tonnes, production of 4.5 to 5.4 million kg of yellowcake and an anticipated return in the year 1998 to full time operation.This paper will give a brief history of the Mill and focus on the present flowsheet and recent improvements to the process."

Jan 1, 1996

By P Bergin, J M. Galvin, J Harris, J Li, P Kirsch, M Shi, B Hebblewhite, B Whittaker, R Mitra, D Sprott

Controlling unwanted ground movement is critical in mining as well as many other highly hazardous environments, such as construction and tunnelling. Sharing knowledge about effective hazard management is paramount to improving health and safety and operational outcomes across industries, and some industry sectors have embraced this openness as part of the way that they do business. In 2010, the Australian Coal Association Research Program funded the RISKGATE project to build a body of knowledge for managing a broad range of hazards across mine sites, lease areas and mine infrastructure within a mine-life or product life cycle perspective (eg from exploration through to decommissioning, or design through to operation). The RISKGATE body of knowledge was assembled from Australian coal industry experts through a semi-structured bowtie analysis-based action research workshop cycle. By capturing operational knowledge from industry experts, RISKGATE serves to provide a cumulative corporate memory at a time of high personnel turnover in the coal industry.This paper presents an overview of RISKGATE topics within the geological and geotechnical domain (strata underground, ground control open cut, outburst, coal bumps and bursts, tailings dams and inrush) with a summary of individual topic structures, as well as showing the contrasts and inter-relationships between these ground management topics. The online user can access information about the causes, controls and consequences related to a priority unwanted event (ie the point at which control of energy is lost) and use this information as a prompt for the development of risk assessments, incident investigation, audits of practice/plans/procedures and for training and development.The paper concludes with a discussion of how RISKGATE can be adapted to other mining domains (eg coal outside of Australia, hard rock mining worldwide, construction, tunnelling) and the opportunity for application of this body of knowledge and the RISKGATE action research process for knowledge management in other highly hazardous environments.CITATION:Kirsch, P, Hebblewhite, B, Sprott, D, Harris, J, Li, J, Shi, M, Whittaker, B, Galvin, J M, Bergin, P, Mitra R and Williams, D, 2014. RISKGATE – shared coal mining knowledge for managing risks across ground management, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 247–254 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

Using mines in Canada, Boart Longyear, a leading provider of drilling services and products, has put its Stage 3 Coring Bit to the test and each time the bit has passed the test with great success. After more than a year in the field at a major mine operation in Sudbury, Canada, the Stage3 coring bit broke life records to become recognized as the most productive design in the industry. In addition to the proven advantage seen in regular bit life increases of as much as 300 percent in some cases, the design is quickly being recognized for its cost-saving operational impact. In Sudbury, the mine operation realized actual cash savings of more than C$45,000 within an eight-month period by making the switch to Stage3 bits. For years, the Sudbury Basin team has relied on the Alpha Extended Crown bit with the Express Waterway geometry option, ordering approximately 500 units per year. This 07 COM ECEX configuration performed well in medium-hard, non-abrasive to ultra-hard, non-abrasive formations with an average bit life of 150 m (490 ft). While satisfied with the performance of the Alpha Ex-tended Crown, the team agreed to put the new Alpha Stage3 to the test. Boart Longyear?s field engineers supplied five drill sites with Alpha Stage3 bits in a 07 COM configuration. After thoroughly testing the Stage3, the results were clear. Even with the well-known performance and versatility offered by the previously preferred configuration, the Stage3 set a new standard of bit performance. The new bit maintained its cutting edge for up to three times longer than the Alpha Extended Crown, a significant performance increase when compared to the 07 COM ECEX.

Jan 1, 2009

By Ravichandar. D., K. B. Nagashanmugam, M. S. Pillai

"Blast furnace performance depends strongly on the coke reactivity index(CRI) and coke strength after reaction (CSR) properties. An innovative and cost-effective method, known as the Salem Box Test, has been developed to prevent the mass production of inferior coke unsuitable for blast furnace use. This method consists of coal carbonization on a micro-scale and involves charging approximately 18 kg of coal blend in a stainless steel box, carbonizing it together with coal cake in the plant coke ovens, and testing the coke produced for CRI and CSR to determine its suitability for blast furnace use. Only coal blends that yield coke with CRI <25% and CSR >64% are permitted for mass production, and other coal blends are either rejected or the blending ratios adjusted in an attempt to upgrade them. The experimental results reveal that, for a given coal blend, the quality of coke produced by the Salem Box Test is comparable with that produced by bulk production, indicating that the test is acceptable as a screening tool for regular use. The present paper describes the methodology and application of Salem Box Test to predict the suitability of coke for blast furnace use at JSW Steel Limited, Salem Works (JSWSL), and illustrates its advantages in adjusting the coal blending ratio to produce superior coke, in detecting coal contamination, and in preventing bulk production of inferior coke."

Jan 1, 2015

A detailed study of the capital investment and production cost for copper electrowinning plants shows that significant savings in both can be achieved by increasing the current density. From the economic analysis it is determined that the optimum current density which will result in lowest capital investment and lowest operating cost is between 60 A/sq. ft. and 70 A/sq. ft., or at least three times as high as the Conventionally employed current density. The specific investment, expressed as $/ton-year, is found to be a function of both the current density and plant capacity and has a minimum value at the optimum current density. Empirical equations are developed for the purpose of estimating the capital investment and operating cost for plants of any production capacity operating at any current density.

Jan 1, 1972

By Barry James

Energy, like labour and materials, is one of the basic production inputs in the industrial minerals industry. This paper discusses the significance of the changing energy situation in Canada as it affects the industry. It is apparent that the importance of energy as a management concern has increased considerably since 1973. The importance placed on energy management today will undoubtedly be an important factor in determining company and industry sector strength and profitability tomorrow.

Jan 1, 1978

By Ailton Lopes Junior

O projeto desenvolvido na ITM Samambaia – Itatiaiuçu – MG, de propriedade da Mineração Usiminas, teve como objetivo a implantação de um Sistema de Controle e Supervisão através do fornecimento de todo o equipamento de automação e desenvolvimento dos aplicativos de controle e supervisão. Este projeto torna possível a operação remota de toda a planta, através de uma sala de controle central, bem como, a automatização de processos como sequenciamento de partida e parada, e o monitoramento do funcionamento de todos os equipamentos da planta, além de ferramenta de acesso remoto via internet para monitoração e comando da planta, mediante política de segurança de acesso.

Jul 30, 2018

By R. A. RAGATZ

THE preparation of specimens for microscopic examination from metal articles of relatively large cross-section offers no particular difficulty. It often happens, however, that articles submitted for examination are so thin that specimens satisfactory for microscopic examination can not be successfully pre- pared by the methods commonly employed when working with larger articles. Ordinarily, the preparation of metallographic specimens involves the following operations : (1) cutting the small specimens to be examined out of the larger mass of metal, (2) cleaning and electroplating, (3) mounting to furnish support during the grinding and polishing operations, (4) grinding and polishing to produce a scratch-free surface, (5) etching and drying. All of these operations must be carried out in such a manner that when the specimen is finally examined under the microscope, the structure seen is a true and well-defined representation of the structure that the larger mass of metal possesses at the place where the small specimen was removed. It is important that the deformation involved in cutting out the specimen be as slight as possible, in order that the subsequent grinding and polishing operations will completely eliminate the cold- working effects in the vicinity of the cuts. It is also important that the specimen never be allowed to attain a temperature high enough to alter its structure; the maximum permissible depends on the metal being handled. With some metals, zinc for example, consider- able care must be taken to avoid heating; with other metals, annealed steel -for example, no particular pre- cautions need be observed because there is no tendency for structural change to occur at relatively low temperatures.

Jan 1, 1929

By Mick Fritz, Tom Treleaven

The success of any blast is dependent on the accuracy of the blast design and field controls placed at the shot location. The procedure by which the data is collected and analyzed is paramount to accomplishing the anticipated blast results. lf the geometry of the blast is not measured correctly, then the results will not meet expectations. Measuring the geometry and compensating for bole hole deviations is crucial not only to the lnitlal blast but also for any consecutive blasts. Excessive bore hole deviation can cancel any new technology in use. However the instruments and skills required solving this Issue are readily available.

Jan 1, 1998

By Higgins RJ

Environmental investigations have been undertaken by Ok Tedi Mining Limited (OTML) since 1981 when the Ok Tedi Environmental Study was commenced. Environmental monit- oring and management programmes were implemented in 1983. The programmes included water quality monitoring, river flow and sediment monitoring, surveillance of aquatic biological communities and a health and nutrition survey of the local people. These original programmes have continued, and additional programmes of work have been developed and revised to reflect changing operations and the need to focus investigations on specific areas and issues of concern. In April 1990, following the establishment by the Government of Papua New Guinea (PNG) of environmental management criteria for the Fly River system, compliance monitoring programs were introduced. Details of the compliance and additional monitoring programmes undertaken by OTML throughout the Ok Tedi and Fly catchments, including programmes of investigation in the Fly River estuary, Gulf of Papua and Torres Strait, are presented.

Jan 1, 1991

By Lawrence M. Gochioco

The interpretation of coal seismic data requires a certain precision and accuracy to make the results more reliable. The signature of the seismic wavelet provides a host of valuable geologic information. Subtle features and anomalies, not easily observed in conventional black and white seismic sections, are enhanced through color attribute displays in terms of frequency, amplitude and phase. Coal seam anomalies like sandstone washouts produce a distinct pattern in frequency and amplitude displays due to the change in the net acoustic impedance contrast. Faults produce frequency and amplitude variations due to interference within the Fresnel zone that straddles the fault. The magnitude of displacement is estimated by studying the effects of faults on reflection amplitudes and frequency from computer-generated models.

Jan 1, 1989