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By R. J. Hickson

The giant El Abra copper mine project under development in Northern Chile will come on stream in early 1997 at a production rate of 500 million pounds of cathode copper annually. Ownership is 51 % Cyprus Amax and 49% Codelco. Cyprus Amax has construction responsibility. Total project cost is $1050 million. El Abra will incorporate latest operational technology with labor efficient practices to achieve world class productivity levels and low initial cash costs of about US $0.35/lb copper. Development procedures for the almost 800 million ton oxide deposit, as well as the hydrometallurgical processes selected for recovery of the copper values are discussed. Construction costs and pertinent technical data are shown.

Jan 1, 1996

By J. J. Sammarco

Computer-aided control of a mining machine pl aces its operator in a safe, remote location, thus reducing health and safety risks, Sensing systems that provide machine position (xy coordinate) and heading (yaw), are extremely useful in aiding remote positioning of mining machines. The U. S. Bureau of Mines has developed two sensing systems for position and heading information: A scanning laser system based on the Lasernet sensor and a mechanical position and heading system based on linear-position transducers. The Bureau is also investigating a system from Honeywell, the modular azimuth and positioning system that employs ring-laser gyroscopes. This paper presents a brief background and status of these sensing systems as applied to the remote positioning tasks of a continuous mining machine. Included are field test results of each system operating in a room-and-pillar research section at a cooperating mine in West Virginia.

Jan 1, 1992

By Low Russell

Mark Westfield, writing in The Australian on 16 May 1994 stated: The role of the independent expert is crucial to Australia's investment system. When it falls down, there can be very dramatic consequences. The scope of these consequences was dramatically illustrated in the decision of Rogers J. at first instance in Cambridge Credit Corporation v. Hutcheson (1983) 8 ACLR 123 when the auditors of the failed company were found liable for breach of contract and faced a damages award of $145 million, well in excess of their insurance cover. No comfort should be sought in the fact that this decision was overturned on appeal, for the result of the appeal rested on whether there had been a causal connection between the breach of contract which had occurred and the loss suffered, rather than on the fundamental principle of auditors' liability. Thus: Those who prepare experts' reports in company cases carry a heavy moral responsibility, whatever their legal duties may be... Unless high standards are observed by those who prepare these reports, there is a danger that systems established for the protection of the investing public will, in fact, operate to their detriment through reliance placed on those reports and on the reputations of those who furnish them. In lending his name, the expert will often, as in this case, be lending a name to conjure With.

Jan 1, 1995

By V. V. Morozov, Ganbaatar Zorigt, Delgerbat Lodoy, Y. P. Morozov

"At the processing plant Erdenet, a new facility for advanced ore diagnostics in-stream (at the conveyor), based on optical analyser of mineral composition, was tested. Such systems provide highly accurate in-stream measurements of ore properties. The system provided information on the ore mineralogical composition, the particle size distribution and the impregnation of minerals. A special flatbed facility for optical spectrum-based estimation of fine-crushed ore has been developed, being incorporated into the existing system of ore sampling and analysis. Application of the flatbed facility renders possible a high accuracy of determining ore mineralogical composition. High precision of the optical spectrum-based estimation is achieved using special devices, installed in the sampling and the sample analysis flow sheet, applied by the technical control department. Modern systems for optical spectrum-based estimation of ore grade provide a basis for effective automated control of ore benefication processes, based on the principle of advanced ore grade control. Process management task of grinding and flotation was to choose options that take into account the composition and grade of the ore coming. The calculation data array comprises consumption of reagents, ore processing, grind size etc. The systems implemented at the processing plant contributed to increasing copper and molybdenum recovery. INTRODUCTION In-stream ore grade analysis is a new trend in effective control of ore benefication processes. This is realised based on radiometric measurements in the X-ray and visible spectrum regions, in which mineral components of the initial ore (Sbárbaro and Villar, 2010) or the benefication products become apparent (Hyotyniemi and Ylinen, 1998; Haavisto and Hyötyniemi, 2010). An important advantage of such methods is in-stream measuring ore parameters, including mass fractions of individual minerals, which makes it possible to use the information obtained in the processes of automated control."

Jan 1, 2018

By J. R. Kadambi, C. Shingote, J. Furlan, R. Ke

"Hydrocyclone separators are widely used in various industrial applications in the oil and mining industries to sort, classify and separate solid particles or liquid droplets within liquid suspensions, which are considered to be multi-phase systems. Numerous valuable studies have been conducted in recent years to investigate the flow fields inside hydrocyclones. However, much of the information regarding the performance of cyclones in the literature has limitations, based in some part on the respective current-available theoretical models, and much of it cannot be considered as completely applicable to most real-world applications; many of the studies investigated the flow fields within extremely simplified hydraulic designs that are not representative of the complex geometries or large sizes which are typical in industry. Therefore, in this study, the two phase flow system inside the actual hydraulic geometry of a milling circuit hydrocyclone was explored with the aid of both computational and experimental techniques (Particle Image Velocimetry). In this study, the flow field with an air core has been investigated; in essence, the research was a two-phase problem, which caused some challenges on both the computational and experimental sides. Two turbulence models were used in the numerical calculations: the Reynolds Stress Model and Large Eddy Simulation. The computational studies are mainly focused on the prediction of the dimensions and shape of the air core. Different section planes of the hydrocyclone were selected as planes of interest and then were divided into several fields of view (FOV) for PIV measurements. Two dimensional experimental velocity vector maps were obtained in each of the fields of view. The computational results were validated globally using pressure and flow rate readings at the boundaries and locally by comparison to the PIV velocity vector maps and profiles. Keywords: Computational fluid dynamics (CFD); Hydrocyclone; Particle image velocimetry (PIV); Reynolds Stress Model (RSM); Large Eddy Simulation (LES). INTRODUCTION A hydrocyclone is a device used to separate a solid-liquid, liquid-liquid, solid-gas, or liquid-gas suspensions into at least two separate density or particle size components. Hence, the flow field of the hydrocyclone is generally considered a multi-phases flow system. Application of hydrocyclones have been used in numerous industries including oil, drilling, metal working, and mineral processing since 1891, when E. Bretney obtained the first patent for the predecessor design of all contemporary hydrocyclones. A modern hydrocyclone typically consists a cylindrical section at the top where the liquid is being fed tangentially, and a conical chamber attached to the bottom of the cylindrical section, as shown in Figure 1. The characteristics of the feed stream that is injected into the cylindrical chamber play a significant role in hydrocyclone operation. The inlet is tangential relative to the cylindrical chamber and hence causes a centripetal force in the flow field which is considered as the primary separation mechanism."

Jan 1, 2017

By J. D. Clendenin

Systematic practices for protecting crops from frost damage began in the United Metes more then 40 years ago when the Weather Bureau Fruit-Frost Warning Service was organized; however, various practices employed in frost protection are centuries old. Although there are areas where little doubt exists as to whether protection is needed, there are also circumstances where there is some doubt as to the need for frost protection. Many factors influence this, including not only critical temperatures but also the maturity dates of the crops relative to marketing. Critical temperatures for frost damage to trees, plants, blossoms, and fruits very with weather, plant variety and nutrition, and stage of growth. In the case of truck crops, a single night of protection from frost injury might yield big dividends with a variety of sweet corn or tomato that matures early while price is high yet be worth very little with a midseason or late-maturing variety. Consequently, it is the individual grower who must decide whether to use frost-protective measures on the basis of his returns, the quantity and quality of his crop, the marketing situation, the sensitivity of his crops to frost damage, and the frequency of damaging frost in his area.

Jan 1, 1955

By Jan M. Mutmansky

Since 1973 when the first edition of the SME Mining Engineering Handbook was published, many significant changes have occurred in the US mining industry. The industry went through a fairly prosperous period immediately after 1973, but then many economic pressures came to bear on mining companies, particularly in the metal and coal branches of the industry. These pressures changed both the mining methods used and the general economics of the mining methods. As a result, the industry today is different in many ways titan it was in 1973. A general summary of some of the more important changes that have come about will be provided here as well as some assessment of the effects of these changes on the choices of mining methods. In the metal mining industry, the most significant trends were increased surface mining, the use of larger and more efficient equipment, and increased technology and automation. The primary impetus for these changes was unprecedented competition from foreign producers. In many cases, this competition came about because of the nationalization of foreign mines and the tendency for these mines to become a source of foreign exchange. Under these circumstances, the mines could be operated even though they were not profitable. As a result, domestic

Jan 1, 2008

By R. J. Kolada

The ventilation systems of coal storage silos are normally capable of rapidly dispersing any accumulations of methane in the atmosphere above the coal pile surface. However, the results of an investigation which is presented in this report show that hazardous concentrations of methane can accumulate within the coal pile. Methane trapped within the coal pile is released into the atmosphere of the loading gallery when coal is discharged from a silo. If the methane released is of a flammable concentration it is necessary to ventilate the gallery to reduce the risk of an ignition. This report proposes a simple test, which, after further investigations may prove to be an effective method to calculate gallery ventilation requirements.

Jan 1, 1985

By W. G. Davenport

Changes in copper extraction from 1960 till today are documented. The top ten changes have been: (a) replacement of reverberatory smelting by high intensity oxygen rich smelting (b) growth of the Outokumpu flash smelting to over 50% of the world's smelting capacity (c) successful development of single furnace coppermaking but only for low slag fall concentrates (d) replacement of the batch Peirce-Smith converter by continuous converting, but only in a few cases (e) increased SO2 capture throughout the industry, mainly-as sulfuric acid (f) development of low initiation temperature `big bight' Cs catalysts for treating the continuous high-SO2 strength gases from continuous smelting/converting (g) complete replacement of reverberatory anode scrap and cathode melting furnaces by the Asarco shaft furnace (h) adoption of stainless steel permanent cathodes and automated stripping technology for electrorefining and electrowinning (i) complete elimination of wire bar casting by continuous bar casting/rod rolling (j) development and adoption of extractants for turning weak impure leach solutions into strong pure electrolytes. It is postulated that the biggest possible change over the next 20 years would be complete replacement of smelting/converting by hydrometallurgical processing. However, this seems unlikely due to copper purity, precious metal recovery, and economic concerns. The increasing value of sulfuric acid to many copper companies gives chalcopyrite smelting/oxide-supergene leaching a nice synergy especially with the energy credits now coming from continuous smelters, and their acid plants.

Jan 1, 1999

By Barton K. Cross

The objectives of this effort were to: 1) Develop and validate start-of-shift operational inspection procedures to be used by operators of mobile, self-propelled equipment used in surface mining operations; 2) Evaluate user acceptance of the developed procedures; and 3) Recommend methods and media for presentation of the developed procedures to the user population. Mobile, self-propelled surface mine equipment requiring start-of-shift inspection was identified. Subsystems amenable to operational inspection were identified. The procedures addressing all safety critical subsystems on each equipment type were then developed and validated. The inspection procedures developed were those that could be performed largely from the operator's station. User acceptance was evaluated during on-site data collection visits to surface mines. Representatives of the user population reviewed the procedures and were then interviewed. Recommendations for the methods and media of presentation to the user population were developed from information obtained in: 1) Review and analysis of instructional technology literature applicable to this area; 2) On-site data collection; and 3) Analysis of the working environment and characteristics of the user population.

Jan 1, 1977

By C. P. Bowie, George L. Gates

"INTRODUCTION Experience in drilling oil and gas wells has shown that the voidance of blow-outs, twist-offs, fishing jobs, loss of circulation, and heaving and caving of shale formations into the drill hole depends largely on how well the drilling-mud fluid serves its purpose. A possible method for the control of the drilling fluids may be seen from a study of the relation between the particle-size distribution and some of the important drilling-fluid properties, such as the ability to build quickly a relatively impervious mud sheath on the wall of the hole in the porous formations penetrated by the bit during drilling operations. In a wartime economy, which urgently requires conservation of steel, proper functioning of the drilling fluid is particularly important because, as Parks 4/ has stated, intelligent use of good drilling fluids makes possible drilling of wells for thousands of feet in open holes without the necessity of setting protective strings of casing to control the movement of salt water, gas, and troublesome formations into the borehole; consequently, especially in deep wells, of proper drilling fluids materially reduces the need for casing and lowers the cost of drilling and completing the wells."

May 1, 1942

By E. R. Cole

This Bureau of Mines investigation was prompted by the need forr a stable anode for electrowinning metals, particularly zinc and copper, from acid solutions. The polarization behavior of Pb-Ag (1 pct Ag) anodes in H2SO4 and fluoride solutions was determined as the first step in the development of such an anode. A Luggin capillary, dc power supply, high-impedance voltmeter, and other equipment standard to an electrochemical laboratory were used in this study. It was determined that during polarization, a relatively hard, stable coating of Pb02 was formed on the surface of the lead-silver anode and the rate of formation of this coating was considerably enhanced by the presence of fluoride ions in solution. Subsequent investigations at the Bureau of Mines Rolla Research Center resulted in the development of a Pb02-coated titanium (Pb02-Ti) anode. Results of this effort were presented in Bureau of Mines Report of Investigations 8111. Additional data resulting from extensive testing of the Pb02-Ti anodes, as well as process improvements and innovations, are included in this report. The anodes were considered generally unsatisfactory for zinc electrowinning because of lower conductivity, higher oxygen overvoltages, and shorter in-cell life as compared with the Pb-Ag anodes now being used in industry. However, the PbO2-Ti anodes were used successfully to oxidize waste chromium solutions and to electrowin copper.

Jan 1, 1981

By Andrew Slifka, Pello Uranga, Douglas Glenn Stalheim

Structural steel final mechanical properties of strength and ductility are predominately generated by the final ferrite grain size/packet size and homogeneity of that ferrite grain size/packet size through the cross-sectional area. Forty to seventy percent of the strength components come from how fine the final cross-sectional ferrite grain size/packet size that can be produced.[1] All the ductility properties of structural steels for a given microstructure are predominately driven by how fine AND homogenous the final cross-sectional ferrite grain size/packet size can be refined.[2,3,4] One key ductility property of structural steels used in construction and energy transmission applications is fatigue. Both low and high cycle fatigue can be realized in these end applications, however, low cycle fatigue is typically the predominate mechanism. In construction applications the environment for fatigue is typically air, such as in wind towers or high-rise building construction. In energy applications, there is an interest in high pressure (5.5 – 21 MPa, 800-3000 psi) gaseous hydrogen as an alternative fuel source to fossil fuels. A project to study the effect of the cross-sectional grain size/homogeneity of a relatively pure polygonal ferrite microstructure on the fatigue performance in air and high-pressure gaseous hydrogen has been developed. This paper will discuss the project strategy, microstructure developed for the project and initial test results.

Oct 1, 2019

By Michael J. Klishis

Accident rates continue to show that underground mining jobs areamong the most hazardous occupations in the United States and roof bolter operators continue to have one of the highest accident incident rates (MSHA, 1991) despite efforts by labor, government, and industry to reduce and eliminate work-related hazards. In the last two decades we have seen technical innovations such as the ATRS, and there has been an increased emphasis on hazard awareness through programs such as MSHA's REAP, but bolter operators continue to be injured and killed. Researchers at West Virginia University examined risk in the roof bolter's job and developed new approaches to accident and injury prevention. The study concentrated on the workers' job performance, machinery and the work environment to identify miner's risk and hazard exposure while bolting.

Jan 1, 1993

By Kengo Usui

The energy consumption of Iron-making, especially Blast Furnace (BF), is very large. In order to maximize the utilization of limited resource, it is essential to reduce energy consumption and recovering waste energy in BF. This paper introduces energy saving equipment based on NSENGI’s over 80 BF construction experiences since 1963. The first is the technology for the Top Charging System for low fuel-rate operation. One of the important factors to achieve such operation, the burden should be charged uniformly. Since 1974, NSENGI have developed and delivered over 80 Top Charging equipments for such purpose and nowadays, developed new type Top Charging equipment with improvement of charging precision. The second is the technology for Solely BFG Operation in Hot Stove, which means no use of other fuel gas such as LDG, COG. It is realized by high combustibility of NSENGI’s Top-Combustion Hot Stove with Metallic Burners, and large amount of heat recovery of Waste gas Heat Recovery system with heat medium. The third is the technology for effective energy recovery in TRT. With NSENGI’s latest Gas Cleaning System “Multi-Vessel Electrostatic Precipitator" (MVEP), TRT will be able to generate higher electrical energy by approx. 30% than that of wet-type. In comparison with dry bag-type, MVEP allows temperature fluctuation which lead to generate higher electrical energy by approx. 10% NSENGI therefore, will be able to accept and meet your request widely.

Aug 1, 2018

By QINGXIANG CAI, Lin Li, PENG LIU, IZHAR MITHAL JISKANI, XIANG LU, Wei Zhou, YONGLI ZHOU

The concept of green mining is to improve the mining industry in a holistic way so that it is safe, efficient, and environmentally sustainable. The purpose of this study was to develop an evaluation index system of green surface mining based on the theory of green grades. The evaluation model is comprised of three attributes (safety, efficiency, and environment), nine criteria, and 35 indicators. The fuzzy comprehensive evaluation method was used to determine the weights of indicators by taking into consideration degree centrality, closeness centrality, and betweenness centrality. Findings indicate that the environment is the most critical aspect of green surface mining, followed by efficiency and safety. The top five ranked green mining success indicators were the application of new technology, starting-off-rate of equipment, science and technology input to total investment, the number of accidents (decreased), and the production (increased). It was observed that more improvements are needed to overcome water, air, waste, and sound pollution. Attention should also be paid to land reclamation and post-mining land uses, which are key factors in green mining. The proposed model can be applied to evaluate and improve the level of green surface mining in other regions. This study provides a tool for decision-makers that can offer technical assistance to green mining.

May 26, 2020

By C L. Briend, O&apos

This paper presents the main features of coal mining in Japan, as determined by the author while attending the International Coal Conference in October of 1963. The general economy of the country is considered, and the requirements for coking coal are outlined. Statistics and comments on production and consumption are then given, with accompanying cost figures, and the characteristics of Japanese coal mining are compared with those of Canada. Mining methods and underground transportation are covered, with emphasis on undersea mining. Finally, a description is given of a visit to the Miike colliery, the largest in Japan. I T was my privilege to attend the International Coal Conference held in Tokyo in October, 1963, to meet many prominent members of the Japan Coal Association and to visit one of the major coal fields. This is probably the reason why I was asked to present this review of the coal situation in Japan. In doing so, it must be pointed out that I am not an expert in coal mining, that my

Jan 1, 1965

By Andreas Orth

Outokumpu Lurgi Metallurgie has developed a process for the calcination and reduction of laterite nickel ore tines where the reduction of iron and nickel to the wustite/metallic states respectively, is performed in a fluidized bed reactor using reduction gas generated very cost effectively from natural gas in an autothermal catalytic reactor. As an option coal can be used as reductant as well as additional fuel. The process of reduction and calcination is very energy optimized. It uses the off gas from the fluidized bed reduction reactor, which still contains energy, to dry and calcine the nickel ore fines in a primary stage circulating fluidized bed (CFB) reactor. The product shows high metallisation of nickel and iron oxides reduced to the wustite stage. This results in considerable energy savings in smelting the prereduced product to ferro-nickel. Alternatively the product can be leached to produce nickel. Laboratory tests showed very high recovery of nickel and cobalt. Keywords: Fluidized Bed, Prereduction, Calcination, Ferro-Nickel

Jan 1, 2004

Jan 1, 1987

By E. Rex, T. J. Goff, W. S. B. van Beek, P. E. Nel

"The PGM smelting industry is known for operating at significant high superheats. Both the slag and matte phases that separate via gravity need to be tapped out of the furnace in a safe and efficient manner, which can be achieved only through sound tap-hole management practices. This paper gives an overview of the tap-hole management approach followed in the operations at Lonmin’s Western Platinum Smelter.Five circular AC furnaces are operated, with each furnace comprising essentially a crucible and auxiliary equipment. Within the crucible, slag and matte tap-holes are situated at different elevations. The slag phase is tapped at a higher elevation than the matte phase. At the three older furnaces, tapping is done by the conventional method of lancing open the tap-hole and closing it with a dolly. However, at the two newer furnaces, tap-holes are opened and closed with the aid of a drill and mudgun.Tap-hole management can be divided in a number of aspects. In order to achieve a safe opening and closure every time, Lonmin distinguishes between three important aspects - the design of the tap-hole system, the operating practices followed, as well as care and maintenance. This paper briefly describes the tapping channel and cooling requirements for handling superheated matte, together with the difference in design of the matte and slag tap-holes. Mention is also made of the importance of auxiliary equipment, which includes the launders, fume extraction, granulation water, and mudgun and drill units. Improvements made to the matte tapblock design are discussed.The monitoring, alarm, and safety systems related to matte and slag tapping are described. Tap-hole life and different wear mechanisms are mentioned. Tapping can be done safely only if the tap-holes and equipment are maintained properly. Mention is made of the tap-hole refractory repair practices, and the improvements made in order to reduce repair time as well as to extend the time between deep repairs. The importance of the correct tap-hole clay selection in order to nurse the tapping channel after each tap is also discussed.The paper finally touches on some research and development work that was done in order to improve the monitoring of the condition of the tapblock by means of fibre optic temperature sensors"

Jan 1, 2014