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By Richard J. H. Barclay

The Lac Otelnuk iron property is located in the Province of Québec in the Northern Labrador Trough. The Labrador Trough is an extensive geosyncline of Proterozoic rocks, unconformably underlain by Archean gneisses. The Lac Otelnuk iron property hosts two significant magnetite iron-formation taconite deposits that outcrop, are sub-horizontal and are known to extend for at least 25 kilometres along strike. The host sedimentary rock package that includes a cherty iron formation is weakly metamorphosed to greenschist facies.

May 1, 2007

By Jilai Xue

Oxygen gas bubbles generate on anode during Pb electro-deposition process in PbSiF6-H2SiF6 aqueous solutions at room temperature. Cell voltage varies as the bubbles formed on the anodes surface. The bubble layer on the anode makes a voltage drop that consumes energy in the Pb process, which can be reduced by applying ultrasound on the anode. The effects of ultrasound frequency and anodic current density were investigated with ultrasound on and off, alternatively during the Pb electrode-position process. The removing of the gas bubbles were recorded in association with a drop in the cell voltage. The cell voltage can be lowered by 4% - 6% with ultrasound, which has potential for energy saving in Pb production.

Jan 1, 2010

By Stephen Hardcastle

Supplying ventilation in underground metal mines can be one of the most energy demanding services required to support production activities. Consequently, as energy, in the form of electricity or combustible fuels can be expensive and their unit cost is expected to increase, there is significant interest in reducing the overall demands of a mine?s ventilation system through such initiatives as controlling ventilation based upon demand and exploring other power alternatives to the current usage of the diesel engine in mobile mine vehicles. However, determining the benefit of any energy saving technology is complex and not universal applicable across the industry, consequently they have not been widely adopted. For these technologies to succeed they must be strategically applied based upon sound business cases. The intent of this paper is to provide information on some of the prospective control strategies and their potential impact on the power consumption related to supplying ventilation.

May 1, 2007

By William R. Yernberg

The current state of the copper industry was the topic of discussion at the Copper 99 — Cobre 99conference held Oct. 10 to 13, 1999, in Phoenix, AZ. More than 700 copper-industry engineers, executives, consultants, academics, vendors and other interested parties attended. This successful and well-organized conference was the fourth in a series of international conferences devoted to the mineral processing and extractive metallurgy of copper. The 1999 meeting marked the first time that the conference was held in the United States. The meeting was co-organized by the Minerals, Metals and Materials Society (TMS); the Chilean Institute of Mining Engineers (IIMCH) and the Metallurgical Society of the Canadian Institute of Mining, Metallurgy & Petroleum(CIM). The meeting was also sponsored by The Society for Mining, Metallurgy and Exploration Inc.

Jan 1, 2000

By Jewel Andrew Gomes

Arsenic is considered as one of the toxic materials being controlled by Environmental Protection Agencies in several developed and developing countries. It is found in the nature as constituents of the soil, minerals and also in various organic forms. It enters the air, water, and land from wind-blown dust and gets into water from runoff, leaching, soil erosion and anthropogenically from chemicals used for wood preservation, insecticides, medicine, military purpose, pigments, and electronic circuitries. There are several techniques available for removal of Arsenic, such as coagulation/filtration, lime softening, ion exchange, reverse osmosis, nanofiltration, wet chemical, and electrochemical. Electrocoagulation has been found as one of the most efficient techniques to remove inorganic arsenic with more than 99% efficiency. In this paper, we present our work on electrochemical treatment of both the inorganic and organic arsenic from water using various sacrificial electrode materials, i.e., iron, aluminum, copper, and combination of them. The floc produced by this method has been also characterized using XRD, SEM/EDS, FTIR, and cyclic voltammetry.

Jan 1, 2010

By Carl A. Zapffe, M. Eleanor Haslem

The present investigation has three principal purposes: 1. To develop a method for measuring hydrogen embrittlement that avoids cer, tain errors complicating previously used methods. 2. To explore in a preliminary way some of the fundamental factors controlling embrittlement. 3. To apply the measurements specifically to stainless grades of steel, whose sensitivity or insensitivity to hydrogen embrittlement has never been clearly defined. Selecting a Test Method Hydrogen embrittlement is a condition of low ductility resulting from excessive absorption of hydrogen by the steel at some period in its history, and may be revealed by almost any test involving cold deformation. Tensile tests, impact tests, and bend tests are commonly used for detecting hydrogen embrittlement; although numerous other tests, such as cold-upsetting or extrusion, could be used. The simplicity of using a wire specimen for cathodic and acid pickling tests, and the especial adaptability of the bend test to wire specimens, led to selection of the bend test for the present research. Bend tests usually have been of three general types: (I) fatigue, (2) reversed bend, and (3) single bend. The first two types, though widely used, are inaccurate because their measurements are counteracted by an aging effect; and the third type has not been developed to its fullest utility. The effect of cold-working in removing hydrogen is well known. During a bend test hydrogen can be observed escaping from the convex side simply by coating the specimen with oil; and any technique employing flexing or reverse bending may therefore have its measurements masked because the mechanical action reduces the embrittlement during the test. This factor is so important that even elastic flexing of a hydrogen-charged wire specimen should be avoided before testing if accurate measurements are desired. Developing a Machine for Measuring Hydrogen Embrittlement As for the single-bend test, its theory is good, and recovery caused by mechanical work is kept to a minimum. With a given degree of hydrogen embrittlement, a specimen will break at a given angle if the bending is applied unidirectionally and uniformly. The radius of the bend must be kept constant; and the rate of bending should be a constant, slow enough to allow reading of the breaking angle, and yet rapid enough to prevent significant recovery from the escape of hydrogen during bending. A simple apparatus (Fig. I) was constructed using a type H Foxboro drive unit A, which is a synchronous motor with a gear-reduction ratio of 600 to I. A cord, fixed at one end to a wooden pulley B on the drive shaft of the motor, follows the pe-

Jan 1, 1947

By Carl A. Zapffe, M. Eleanor Haslem

The present investigation has three principal purposes: 1. To develop a method for measuring hydrogen embrittlement that avoids cer, tain errors complicating previously used methods. 2. To explore in a preliminary way some of the fundamental factors controlling embrittlement. 3. To apply the measurements specifically to stainless grades of steel, whose sensitivity or insensitivity to hydrogen embrittlement has never been clearly defined. Selecting a Test Method Hydrogen embrittlement is a condition of low ductility resulting from excessive absorption of hydrogen by the steel at some period in its history, and may be revealed by almost any test involving cold deformation. Tensile tests, impact tests, and bend tests are commonly used for detecting hydrogen embrittlement; although numerous other tests, such as cold-upsetting or extrusion, could be used. The simplicity of using a wire specimen for cathodic and acid pickling tests, and the especial adaptability of the bend test to wire specimens, led to selection of the bend test for the present research. Bend tests usually have been of three general types: (I) fatigue, (2) reversed bend, and (3) single bend. The first two types, though widely used, are inaccurate because their measurements are counteracted by an aging effect; and the third type has not been developed to its fullest utility. The effect of cold-working in removing hydrogen is well known. During a bend test hydrogen can be observed escaping from the convex side simply by coating the specimen with oil; and any technique employing flexing or reverse bending may therefore have its measurements masked because the mechanical action reduces the embrittlement during the test. This factor is so important that even elastic flexing of a hydrogen-charged wire specimen should be avoided before testing if accurate measurements are desired. Developing a Machine for Measuring Hydrogen Embrittlement As for the single-bend test, its theory is good, and recovery caused by mechanical work is kept to a minimum. With a given degree of hydrogen embrittlement, a specimen will break at a given angle if the bending is applied unidirectionally and uniformly. The radius of the bend must be kept constant; and the rate of bending should be a constant, slow enough to allow reading of the breaking angle, and yet rapid enough to prevent significant recovery from the escape of hydrogen during bending. A simple apparatus (Fig. I) was constructed using a type H Foxboro drive unit A, which is a synchronous motor with a gear-reduction ratio of 600 to I. A cord, fixed at one end to a wooden pulley B on the drive shaft of the motor, follows the pe-

Jan 1, 1947

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigation beginning with No. 4251, of which this is the thirteenth. The data are accompanied by maps showing the location of holes drilled and the deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township map. The description of each half township is followed by a description of each deposit developed in that half township. The 14 half-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled on the project, except the deep holes drilled to test the geophysical anomalies. The locations of those holes show on figure 13 in volume 1. The description of the deposits developed is followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated and a table for each half township is given with the discussion covering that area.

Jan 1, 1948

By Francois P. Leroy

In the quest of studying the assigned blocks of seafloor for deep water mining, each member country of the ISA is thirsty for accurate information as to the level of resources available. Manganese nodules represent a large portion of the resources and are as precious as they are hard to locate and harvest. Resolving such challenges is what drives the technology development and yields instruments and products capable of serving this field of research. This presentation will study how manufactures of oceanographic instruments have pushed the technology envelop to in order to transform a collection of sensors and instruments into a seamless and adapted assembly working to serve the researcher and prospector in the challenging field they operate. Deep water data collection is characterized by the following challenges: ? Deployment, recovery and handling of the vehicle ? Producing high resolution at great distances ? Positioning that data with accuracy to relocate Teledyne Marine will present the work performed in its engineering laboratories to produce sub systems and systems now capable of delivering key information necessary to the proper cataloguing and exploitation of deep water mineral mining. Understanding and controlling the alternative resources available to each country will allow better management of current traditional land based minerals.

Jan 1, 2010

By Michael Cooper, Eric Konigsmann, A. Moerman

"A paste backfill plant and underground piping distribution system was commissioned at the Brunswick Mine in June, 1998. Concentrator tailings, composed mainly of pyrite and lesser amounts of silicate minerals with a P80 of 37um (45 YO-20 pm), are pumped to the backfill plant. The backfill plant uses conventional thickening and disc filtering to dewater the solids, which are then mixed with binder in twin screw mixers. The paste is discharged through a gob hopper and one of three boreholes by gravity. Approximately 65% of the concentrator tailings will be placed underground at full production. The remaining thickened tailings will be pumped to an existing impoundment area. Application of paste technology will completely replace the use of cemented rock fill in the mine by the end of 1998.The design capacity of the paste backfill plant is a total of 360 dmtph of cemented paste through two parallel production lines. The plant is highly instrumented and controlled via a hybrid Programmable Logic Controller (PLC-5) and Fisher ProVox Distributed Control System that is in communication with the property information highway. Video and audio signals from the underground system are carried to the surface plant via a leaky feeder communications/fiber optic system.The underground distribution system consists of a network of 200mm diameter boreholes and piping. There are approximately 3.5km of boreholes and 5.5km of piping in the system. To minimize pressures, the greatest piping length from any borehole is approximately 400m with all piping being open-ended. There are no valves in the entire paste distribution system.Construction of the plant, including installation of piping to and from the plant and preparation of the underground distribution system, was completed in less than one year from the time of management approval for the $M 22.3 project."

Jan 1, 1999

By Walter Valery, Peter Radziszewski

"The NewCrest Cadia operation boasts the largest SAG mill commissioned last June 1998. A request was made to shed some more light on possible SAG mill charge behaviour. Three different software were used to simulate SAG mill charge behaviour:Mishra/Rajamanis MillSoft DEM charge motion program, Radziszewskis agglomerated DEM charge motion program and Powell/Nuricks MillTraj outer trajectories program. The contexts simulated are: 20/30 % charge volume, 65/75/85 % critical speed using the Hi-Lo lifter configuration specified for the mill as well as a Hi-Lo 60 degre lifter face configuration. Further, lifter interval was also studied to determine the effect on power draft. Power predictions are compared with those obtained during the commissioning period.INTRODUCTIONThe NewCrest Cadia operation is located outside of Orange, New South Wales, Australia. With proven reserves of 190 million tonnes at a grade of 0.75 g/t Au, the mill was designed to process 17 Mtpa (2065 tph) of ore with an 86% copper and 73% gold recovery. The grinding circuit (Fig. 1, Table I) boasts the largest SAG mill (Fig. 2) and was commissioned last June 1998."

Jan 1, 1999

Discussion of the paper of S. E. Bretherton, presented at the Butte meeting, August, 1913, and printed in Bulletin No. 80, August, 1913, pp. 1481 to 1487. S. E., BRETHERTON, San Francisco, Cal.:-Since preparing my paper, our chemist, F. L. Wilson, has been experimenting with Leadville, Colo., oxidized zinc ore and Leadville zinc sulphides containing lead, operating upon 40-1b. lots at a time. His results on Leadville sulphides are as follows: The raw ore contained a trace of gold, 5.04 oz. of silver, 19.1 per cent of zinc, and 7.24 per cent of lead. After roasting the ore contained a trace of gold, 5.72 oz. of silver, 0.75 per cent of copper, 21.7 per cent of zinc, and 8.29 per cent of lead. The loss in weight by leaching was 38.8 per cent. The extraction was 42.8 per cent of the copper, 80.6 per cent of the zinc, 7.1 per cent of the lead, 0.64 per cent of the silver, and no gold. The little .silver that is extracted would be thrown down with the copper when precipitating it from the zinc and both thrown hack into the residue to be smelted. There would be no trouble in smelting the residue with nearly all the sulphur eliminated and containing less than 7 per cent. of zinc. On zinc carbonates containing silicates the results are not satisfactory. H. O. HOFMAN, Boston, Mass. (communication to the Secretary*) :¬The paper by Mr. Bretherton upon the application of ammonia and carbonic acid to the recovery of zinc as oxide from roasted sulphide ore is of interest to me, as the first installation of the Schnabel process for the extraction of zinc from a mixture of zinc oxide, lead oxide (with some cupric oxide), and pellets of enriched lead, produced in steaming liquated zinc-silver-lead crust of the Parkes process, was made at Lautenthal, Harz mountains, where I was chemist. In that capacity I carried out numerous experiments on the Schnabel process, was active in the erecting of the plant, and later had charge of it. After the Lautenthal plant had been in operation for some time a similar one was built at Hoboken-les-Anvers, but both have been abandoned, as the wet process could not compete with the distillation of the liquated zinc-silver-lead crust, now used universally in the Parkes process.

Jan 11, 1913

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 Donald Leroux, Jean-François Wilhelmy, Ahmed Bouajila

"A young private R & D organization, COREM celebrated its 10th anniversary in 2009. Managed by a consortium of nine mining and metallurgical companies, COREM has the mandate of increasing the competitiveness of its member companies through the development and transfer of mineral processing innovations. Typical technologies developed by COREM include alternative mineral processing techniques, novel operating strategies, innovative sensors and process simulation software. Many of them were developed in partnership with universities and selected research organizations.Because the COREM membership base is broad (from ferrous to base, to precious metal industries), its R & D program must deliver technologies with applications within a wide spectrum of mineral processes. Comminution, physical (gravity and magnetic) separation, flotation, cyanidation, pelletizing and thermal processes are the main topics of the R & D program. A number of new technologies have been developed and transferred to the plants of member companies. These examples of transferable technologies demonstrate the capability of COREM to impact the bottom-line of its member companies.INTRODUCTIONCOREM is a private mineral-processing R & D organization that operates from its own laboratories and pilot-plant with its own staff of professionals and technicians (about 95 persons). It is managed and financially supported by a consortium of nine mining and metallurgical companies and three provincial and federal ministries. The very ‘down-to-earth’ mission statement of COREM is to increase the competitiveness of the mineral processing plants of its members. The eighteen plants upon which the COREM technology development program is currently based can be found in Québec, Newfoundland and Labrador, New Brunswick, the Netherlands and Botswana."

Jan 1, 2010

By M. E. Alam

In the present study, 1.1 volume percent of nano size copper was incorporated into pure tin using hybrid microwave sintering assisted powder metallurgy route. Microwave sintered samples were extruded both at room temperature and at 230 °C. Microstructural characterization studies were conducted on the extruded samples to investigate the distribution characteristics of secondary phase and grain morphology. Room temperature tensile test results revealed that hot extruded Sn-Cu samples exhibited higher strengths (~ 41%, in case of 0.2% yield strength and ~ 38%, in case of ultimate tensile strength) and ductility (~ 15%) when compared to room temperature extruded samples. On the contrary, the tensile properties of pure tin remained independent of extrusion temperature. An attempt is made in this study to correlate the effect of extrusion temperature on the microstructural evolution and tensile properties of Sn-Cu solder.

Jan 1, 2009

By Washington Luiz Mafra

Every year the conventional direct reduction processes ? Midrex and HYL III ? increased their market share in the world steel production, even though they are only economically feasible in countries where natural gas is available at competitive prices. In this context, the new Midrex projects are based on large reactors (Megamod - 1.5 to 1.8 Mt/y of DRI), reduction temperatures of the metallic burden up to 850oC, with bustle gas temperatures between 960oC e 1050oC. Thus, the requirements of metallic burden performance, as well as the evaluating methods, usually based on ISO standards, need to be reviewed. It is well known that the standards usually applied to quality evaluation do not reflect the performance of metallic burden inside the reactors. This paper describes the different methods of evaluating the disintegration under reduction of DR pellets based on ISO 11257 standard. This is the most important method used by pellet producers and customers for evaluating DR feedstocks. The different methodologies tested to evaluate the disintegration under reduction had varying results, evidencing the relevance of the method and the quality of the pellet. Nevertheless, validating the method in an industrial reactor is still fundamental.

May 1, 2007

By Colin Lindsay

"The Collahuasi copper mine, located at an altitude of 4300 meters above sea level in northern Chile, commenced operations late in 1998. The mine is currently the 4‘h largest copper producer in the world and comprises an open pit, a 60,000 tpd sulphide concentrator, a 15,000 tpd oxide heap leach and SWEW plant and a 200 km concentrate pipeline to a port facility.Constructing, commissioning and operating a mine at high altitude presents unique challenges in terms of the performance of both equipment and people. It is important that these be recognized and carefully considered during the feasibility study and the detailed design stages and the success of the Collahuasi project is largely due to this. The plant design incorporates a number of features aimed at mitigating the problems of altitude and the construction methodology also took into account the particular site conditions.This paper discusses the Collahuasi project team’s approach to planning for the remote location and also some of the problems experienced during construction, commissioning and operation.INTRODUCTIONThe Collahuasi mine is located in northern Chile, some 250 km to the south-east of the port of Iquique and 15 km from the Bolivian border. The mine facilities lie between 3800-4300 m above sea level on the Altiplano, the central plateau of the Andes mountains, and cover a total of approximately 95,000 hectares. Although the area is arid, it experiences an average of 150 mm of precipitation annually and weather conditions can be extreme. Temperatures during the day range between -3 to +11 º C and are generally below 0ºC at night, sometimes as low as -20°C. High energy winds are common and humidity is low. Much of the precipitation occurs during the winter as snow but there also occurs a period during the Chilean summer known as the “Invierno Boliviano’’ (or Bolivian Winter) which is characterized by severe electrical storms and rain."

Jan 1, 2001

By O. Rielo, P. Katsabanis

Traditionally fine aluminum is not used in dry commercial explosives due to the hazard associated with aluminum dust explosions during mixing. An industrial process has been developed which enables the safe use of paint grade Aluminum with ANFO. The addition of fine aluminum particles resulted in increased velocity of detonation of ANFO compositions. Velocities of detonation, in 52mm (2 1/16 in.) diameter confined charges were 20% higher than velocities of detonation of straight ANFO. The detonation performance of fine grained ANFO was not benefited by Al at the diameter tested. Furthermore use of larger Al flakes resulted in decreased velocities of detonation. The results are compatible with the experience of Al addition to high explosives. Tests were also conducted using bio-diesel, finding no substantial difference in the performance of AN fuel explosive compositions which used bio-diesel.

Jan 1, 2009

By Linda Gaines

Use of vehicles with electric drive, which could reduce our oil dependence, will depend on lithium-ion batteries. But is there enough lithium? Will we need to import it from a new cartel? Are there other materials with supply constraints? We project the maximum demand for lithium and other materials if electric-drive vehicles expanded their market share rapidly, estimating material demand per vehicle for four battery chemistries. Total demand for the United States is based on market shares from an Argonne scenario that reflects high demand for electric-drive vehicles, and total demand for the rest of the world is based on a similar International Energy Agency scenario. Total material demand is then compared to estimates of production and reserves, and the quantity that could be recovered by recycling, to evaluate the adequacy of supply. We also identify producing countries to examine potential dependencies on unstable regions or future cartels.

Jan 1, 2010

By Tammy G. R. Portela

A comparative characterization of the dimensional and mechanical properties as well as structural aspects of two different types of fibers extracted from the leaves and petioles of the buriti palm tree was performed. A statistical analysis revealed that both types of fibers present a significant dispersion in length and equivalent diameter. However, the corresponding intervals of dimensional variation are sensibly different. The tensile properties showed that both types of fibers display a tendency of higher strength for smaller diameters. Moreover, the fibers extracted from the leaves depict a comparatively lower strength. By contrast, the fibers from the petiole present an average strength sufficiently high for the use as reinforcement of polymeric composites. The structural aspects of tensile-rupture fibers, characterized by scanning electron microscopy, showed marked distinction in the microstructure and fiber behavior of both types of investigated fibers. This could explain the differences in mechanical behavior

Jan 1, 2010