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By J Player, P Mikula, G Sweby

A numerical modelling back-analysis exercise was carried out at a WA gold mine at which early signs of seismicity (rock noise, scatts from active faces) were becoming apparent as depth of mining increased towards the 500 m mark. Some strain bursting had occurred and it was necessary to discover what the implications of this were for greater depth. The aim of the modelling was to: 1. Establish a correlation between observed ground conditions and model predicted damage, in overstressed areas of the mine. 2. Use this correlation to forecast rock mass damage and ground control requirements for proposed future stoping panels at greater depth. Good correlation has been achieved between observed rock mass damage, and a 3D Finite-Element RS3 model, run in elastic mode. Two candidate stress field orientations were modelled. The model parameter best fitting the observations was the Strength Factor (SF), the ratio of strength/stress. The good match (correlation coefficient of 0.7) between observed and modelled suggests that the elastic approach is justified for the depth range and rock mass properties analysed. The correlation also enabled a link between observed damage and installed ground support performance. Using the linear best-fit between observed and modelled, a forecasting exercise was carried out using the same RS3 model, modified to include future stoping. The resulting damage and ground support categories were obtained from the modelled SF for each proposed stoping level. Also, a series of generic geometries was assessed to investigate the impact of varying stope face lead/lag distance, sill pillar height and stope pillar size, on ground conditions. The key finding of the generic geometries were: • Ground support schemes have been defined for the expected conditions. • All ore drives are expected to have significant damage in the backs and rehabilitation. • Lead/lag distance not to exceed 10 m. • Sill pillar/level intervals of less than 20 m require an increase in ground support scheme. • Pillar sizes for maintaining footwall and hanging wall stability should be at least 10 m × 5 m.

Nov 29, 2022

By Lee Browne

The transformation of Peru’s Tintaya copper project from a state-owned company to a private company is under way and the results have been successful. Since Magma Copper Co. assumed operating management in December 1994, production and costs have improved dramatically. To understand the transformation of Tintaya, the transformation of Magma Copper must also be understood.

Jan 1, 1996

By M. Tarvainen

"Lately, the development work in closed circuit grinding has mainly been focused on mills and on different types of instrumentation, mathematical models and automation in spite of the fact that the poor efficiency of the classifier is well known. It has also been proven by several investigations that by improving the sharpness of classifier separation, remarkable technical and economical advantages can be achieved. Some attempts to improve the performance of the most common classifier, hydrocyclone, have been made, among them injection of wash water above the spigot cyclone and retreatment of either or both of the products of the primary classifier. No method has been successful enough to achieve general adoption in the industry. The purpose of this paper is to introduce some industrial results achieved by two-stage classification where the coarse product of the turbulent-flow classifier, hydrocyclone, is cleaned in a laminar-flow cone classifier.The main target of the adoption of the two-stage classification circuit it naturally to improve the sharpness of size separation. This again leads to the following advantages in the grinding process:- lower circulating load and increased capacity- lower energy consumptionnarrower size distribution in the fine product- less overgrinding and less slimes- reduced specific surface areaThese improvements, no doubt, reflect on the subsequent concentrating process in the following aspects:the rate of flotation is improved, less reagents and energy is neededthe recovery and grade of valuable minerals in concentrates is improved- savings in dewatering can be expected- less fines in tailings improve the conditions for water recirculation."

Jan 1, 1980

By M A. Jardine, J A. Miller, M Becker, M Harris

"Although the role of texture has been increasingly recognised as a geometallurgical indicator of ore characteristics and their variability, the ability to appropriately quantify and correlate it with metallurgical performance remains an ongoing challenge. In this study, we propose the 3D characterisation and quantification of ore textures from drill core using X-ray computed tomography (XCT) with an appropriate image analysis methodology (grey level co-occurrence matrices, GLCM). This methodology has been specially customised for application of 3D XCT grey-scale volumes. This approach has potential as an online mine site analysis tool providing detailed 3D information on both quantitative texture and simple mineralogy.The approach is illustrated in this paper using drill core samples that were manually extracted from various rock types and textures representing the Nkomati Main Mineralized Zone (MMZ) sulfide nickel ore deposit. A preliminary classification of the samples was performed based on their particle size distribution after laboratory scale rod milling. Accompanying QEMSCAN analyses were also used to guide the interpretation of the grey-scale mineralogy and texture in the 3D XCT volumes. The resultant GLCM produced from quantitative 3D image analysis of the XCT volumes indicated sensitivity to ore variability and was able to capture a simple mineralogy and grain size distribution. The approach holds many possibilities for geometallurgy, of which the potential for automation is promising.CITATION:Becker, M, Jardine, M A, Miller, J A and Harris, M, 2016. X-ray Computed Tomography – a Geometallurgical Tool for 3D Textural Analysis of Drill Core?, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 231–240 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

To reduce the respirable dust generated by auger-type continuous coal mining machines. The Approach: Use water sprays close to the cutting bits on the auger so that coal fragments are thoroughly wetted as they are formed to prevent dust dispersal into the ventilating air. How It Works: The "wet auger" system of dust control uses water sprays distributed on both shafts of auger type continuous miners. This approach has been tested underground by personnel of the Bureau's Twin Cities (Minn.) Mining Research Center on a Wilcox Mark 20 continuous miner, in a cost sharing contract with Buchanan & Sons Coal Company, Inc. Personnel of the Interior Department's Mining Enforcement and Safety Administration collected dust samples and analyzed the data. A test machine was fitted with six sprays on each auger (see Fig. 1). Water flow rates from 8 to 12 gpm at pressures from 90 to 120 psi, or about 8 gallons per ton of coal mined, were required. At these rates of water usage, mining personnel experienced no problems with work-

Jan 1, 1974

By J. A. Cavallaro

The heats of formation of anhydrous barium carbonate (witherite), strontium carbonate (strontianite), and lead carbonate (cerussite) were determined by solution calorimetry. The solution mediums were hydrochloric acid for barium and strontium carbonates and perchloric acid for lead carbonate. The heats of formation at 298.15° K are as follows: BaCO3 -297.5 ± 0.8 kcal/mole; SrCO3 -294.6 ± 0.5 kcal/mole; and PbCO3 -168.0 ± 0.3 kcal/mole.

Jan 1, 1966

By S. C. Carniglia

Bayer-process alumina hydrate becomes in turn the source of a host of special products in addition to the calcines that feed aluminum reduction cells. Though relatively smaller in tonnage, specialty aluminas serve important industrial markets in an exciting and growing variety. Production methods and applications are discussed for: (1) trihydrate as flame retardant in organic materials; (2) high-surface-area transition aluminas as desiccants and scavengers, catalysts and substrates; (3) calcines for industrial ceramics, refractories, and abrasives; and (4) tabular alumina for refractories, bed supports and other uses.

Jan 1, 1977

By Yi Luo

The efforts to mitigate longwall subsidence influences on various residential and farming structures by many coal mining companies have been successful in the recent years (Luo, et al, 2003). The successes were largely dependent on the accurate subsidence predictions, correct assessments of potential influences, appropriate design and implementation of the mitigation measures. However, such efforts for protecting large industrial structures are still very rare. In this paper, the successful assessment and mitigation of the subsidence influences associated with a very intensive dynamic longwall subsidence process on a large workshop are presented.

Jan 1, 2005

By Paulo Sérgio Moreira, Geraldo Lúcio de Faria, Rhelman Rossano Urzêdo Queiróz, Amanda Aparecida Fátima Arruda, Ana Cecília de Carvalho

O objetivo deste trabalho foi avaliar o desempenho em desgaste de camadas espessas de óxidos formadas na superfície do aço inoxidável ferrítico 410D após a sua submissão a tratamentos isotérmicos em atmosfera oxidante. O aço em questão foi estudado no estado de entrega e tratado isotermicamente nas temperaturas de 900°C e 1000°C por diferentes intervalos de tempo. O método de avaliação empregado foi o teste de desgaste micro-abrasivo do tipo esfera presa em placa. Com o desenvolvimento do estudo, foi possível executar análises qualitativas e quantitativas a respeito do comportamento em desgaste do aço inoxidável 410D em função de sua condição superficial, como oxidada ou não. Alterações microestruturais também foram consideradas na discussão dos resultados. Concluiu-se que a camada superficial de óxidos desenvolvida após os tratamentos isotérmicos possui boa aderência e tem potencial para aplicação como camada protetora do aço em aplicações onde a sua resistência ao desgaste seja requerida.

Oct 9, 2019

By Sarah K. DeBono, Alan J. Monaghan, Emmanuel V. Manlapig, Gregory J. Harbort

"The Jameson Cell is a type of flotation machine in which air and pulp are brought together in a vertical tube called a downcomer. Within the downcomer the air and pulp are dispersed into a dense foam of fine bubbles, which creates a favourable environment for bubble-particle collision and subsequent collection of hydrophobic particles. The intense collection zone within the downcomer can be considered similar to the zone between the rotor and stator in mechanical flotation cells.Research into the bubble-particle collision and fluid dynamics of mechanical cells rotor-stator zone has been limited by the difficulty of achieving accurate measurements in production sized machines. With the Jameson Cell the downcomer is largely external and separated from the flotation tank, allowing ready access to the primary contacting zone for measurement and analysis.An investigation has been undertaken into the operating characteristics of the downcomer relating to bubble-particle collision. An effective mapping of the downcomer has been made through measurements of void fraction and bubble size taken across cross sections of the downcomer. Analysis of these measurements has provided an interpretation of the variations in the air and fluid dynamics, bubble size and distribution throughout the downcomer chamber."

Jan 1, 2003

The importance of controlling respirable dust and methane gas levels in underground coal mining cannot be underestimated. While respirable dust can significantly affect the occupational health of underground coal miners, methane gas accumulations pose significant safety concerns for these same workers. Water sprays and machine mounted dust scrubbers offer effective control of respirable dust exposures and methane gas accumulations. Water must not only be applied carefully to avoid dust rollback to the machine operator but must create sufficient turbulence to remove dead zones that could contain high concentrations of methane gas. While the flooded-bed dust scrubber has been generally responsible for decreased worker exposures to respirable dusts, this device has proved effective in controlling methane levels at the face. This paper reviews practical applications of water sprays and dust scrubbers to control respirable dust and methane gas on continuous miner faces.

By Wilton Pacheco de Araújo

A siderurgia gera grandes volumes de escória de aciaria como coproduto e precisa incrementar o aproveitamento desse material em novos processos para evitar a disposição em aterros, aumentando a competitividade do setor. Este estudo tem como objetivo caracterizar a escória de aciaria LD da Usiminas em Ipatinga-MG, buscando avaliar o seu potencial para uso como corretivo agrícola e fonte de nutrientes para agricultura. Foram utilizadas técnicas analíticas tradicionais e microscopia para determinar suas principais características. Os resultados mostraram que uma etapa a mais de separação por peneira (2 mm) no processo rotineiro de remoção de metálicos é possível produzir um produto com características químicas e granulométricas estáveis para se constituir um corretivo agrícola comercial. O material apresenta características superiores aos corretivos tradicionais, pois além de corrigir o pH, fornece nutrientes importantes para a agricultura. O processo mais lento de hidratação dos silicatos e de liberação dos nutrientes pode ser interessante para o fornecimento progressivo desses compostos dando longevidade ao corretivo, reduzindo potencialmente o custo de aplicação.

Aug 16, 2017

By G. Kordosky, A. Feather, M. Virnig, P. Crane

Introduction The post World War II nuclear arms race and interest in nuclear power generation resulted in a significant demand for uranium in the 1950’s. This led to the development of uranium solvent extraction technology and uranium became the first metal to be recovered on a large scale by solvent extraction (SX) (1), interestingly more than 100 years after the extraction of uranium from an acid nitrate solution using diethyl ether was first reported by Peligot.(2) For a variety of reasons discussed elsewhere (3,4) there have been upheavals in the supply demand picture and price for uranium since the 1960’s. (Figure 1) The low price of uranium from the mid 1980’s until 2004 resulted in a depression of new resource exploration and mine development along with uranium mine / mill closures and decommissioning. People with skills in uranium processing could not find suitable employment and many experienced engineers and metallurgists took jobs elsewhere or retired. This resulted in a significant brain drain with respect to uranium processing technology.

Jan 1, 2007

By T. V. Chnyrenkova, J. Troncoso, V. A. Luganov, G. P. Kluev

"Arsenic-gold bearing ores are used as flux in smelting or are leached out with extraction of gold. For decreasing arsenic content in processed materials and for breaking up the lattice and opening up of gold the raw materials are roasted. Some regularity was established for sulfidizing of arsenic bearing compounds in a presence of pyrite and for oxidation of ores and concentrates in the presence of soda.This article analyses the results of laboratory and pilot testing of dissociating and oxidizing roasting of gold-arsenic bearing concentrates. During the dissociation roasting under vacuum arsenic is sublimated into elemental and sulfide forms. This process allows minimizing the negative influence on the environment but requires costly engineering solutions. Roasting in a limited quantity of oxygen in the gaseous phase makes it possible to sublimate arsenic in the form of oxides and sulfides and may be carried out in fluid bed furnaces."

Jan 1, 2003

By H. E. Grier, H. H. Aronson, H. F. Coffer

"Nuclear explosions are currently being planned for use in oil and gas production, the recovery of oil from oil shale, gas storage and copper leaching. The current status of each of these projects is discussed, with emphasis on the economics of each application. The first commercial application of nuclear explosives will be in gas stimulation. Project Gasbuggy will be rapidly followed by two additional shots, also related to gas production. These three events, each in a different formation, will be described in this paper with a discussion on their significance to the world's oil and gas industry. The use of nuclear explosives in oil and gas stimulation should be a standard accepted practice within a few years. Calculations based on explosions in media such as tuff, alluvium, granite and dolomite predict large increases in productivity when nuclear devices are used in tight, thick formations. The broken-up rock resulting from the explosion becomes the new well bore, with a production rate of six to twelve times that of a normally completed well.Also included in the paper is a discussion of the real or possible problems associated with nuclear explosive engineering. The only major foreseeable problem is the seismic shock wave. This limits the size of explosive which can be used near important surface structures. A discussion is included on the radiation problem, which we believe to be largely psychological in the case of contained explosions."

Jan 1, 1968

By Michel Fontaine, Bruno St-Cyr

"The mission of the CENTRE DE RECHERCHE INDUSTRIELLE DU QUEBEC (CRIQ) is to stimulate economic development by guiding businesses in their pursuit of innovation.With a comprehensive approach to their needs, CRIQ provides businesses with expertise based on the most recent developments and insights in the fields of:Research and Development ServicesAutomation and production processesDevelopment of industrial equipmentEnvironmental biotechnologiesTesting and Product Qualification Services Industrial and Technological Information ServicesConsultancy and competitive intelligence servicesIndustrial information bankStandardization ServicesElaboration of standards and product certificationSystems registrationEXPERTISE COMPETENCE, INNOVATIONSince its founding in 1969, CRIQ has been involved in over 100,000 projects. The results of its research and development services have enabled it to build over one hundred pieces of equipment, almost all still in operation today. CRIQ has been and remains the driving force of innovation and expertise on the industrial scene, offering highly competitive solutions to a clientele from numerous industrial sectors.CRIQ became a crown corporation operating on a commercial basis on June 30, 1997. This change in its corporate structure has enabled it to put a marked emphasis on trade and implement an array of new operational practices.The formation of marketing companies with private partners, the opening up to corporate business and international markets, the new directions for internal research and the strengthening of its marketing component are among the activities CRIQ has initiated over the last fiscal year to finally reach its cruising speed."

Jan 1, 2000

By A. M. Ghodgaonkar, P. J. Bhonde, R. D. Angal

Primarily ferrochrome is used to introduce chromium into steels and alloys. Chromium enhances hardness, hardenability, corrosion, abrasion and wear resistance of the steel. High carbon ferrochrome is one the cheapest sources of chromium, which finds large consumption in foundries and steel plants. However, carbon leads to problems viz. weld decay and sensitization of steels at elevated temperature causing catastrophic failure. Thus high carbon ferrochrome which otherwise enjoys financial edge over its low carbon grade is not suitable for final alloying or adjustment of chromium content. Subsequently, its addition burdens a steel maker. Hence, metallurgists around the globe have researched on finding out suitable technique for refining of ferrochrome. Traditional production methods of low carbon ferrochrome have drawbacks i.e. high refractory consumption, losses of chromium in slag and fumes etc-. Later these were overcome by adopting relatively new methods namely, metallothermic reduction, triplex process, vacuum technique to directly produce extra low carbon ferrochrome. Authors have carried SWOT analysis of the aforementioned techniques in the literature. Key Words: Ferrochrome, carbon content, low carbon grade, chromite, sensitization

Jan 1, 2007

By R. G. Burdick

The problems presented by old mine workings affect both present day mining and land development. An automated method of locating these old mines from the surface using electrical resistivity techniques was de-veloped earlier under a Bureau of Mines contract. Subsequent Bureau research has refined the techniques and expanded the area of study to a variety of geologic provinces. During this research, six mining areas in the United States were in-vestigated with the Bureau's automated resistivity method. This report describes the mining areas involved and the results of the resistivity investigations, which showed a high rate of success in detecting old mines. It also describes the field measurement techniques and data analysis procedures.

Jan 1, 1986

By Lynn B. Hales

There is a large economic opportunity associated with improving metallurgical performance in mineral processing plants that use process control. Thus, future control systems will be developed towards more sophisticated user friendly, computer-based systems that use powerful software analysis and control techniques. Auto-tuning, adaptive control and process models will gain expanded use because of their transparent availability to the system designer. Control of individual unit operations will be optimized and coordinated through expert systems that monitor economic conditions and management directives and direct operations accordingly. Plant areas, once considered cost centers, will be integrated into plant-wide control systems for economic control and optimization. This article looks at new control hardware, process sensors, control strategies and software development tools. It also looks at the economics driving the continued development of advanced process control systems. Process control systems routinely used in the mining industry were born when the microprocessor was invented. They have continued along an evolutionary path from vendor specific processing hardware and proprietary operating systems to computer industry standard "open architecture" systems. The many economic forces that drive the development and functionality of these process control systems will cause this evolutionary process to continue. Two of the broadest categories are the needs of the end users and the desire of the system manufacturers to distinguish their products from one another. More

Jan 1, 1994

By Jeanne A. Smith, Suzanne D. Smith

Annoyance, fatigue, and musculoskeletal pain have been reported during prolonged exposures to propulsion-generated vibration in military propeller aircraft1. The objective of this study was to determine the vibration mitigation properties of selected seat cushions and the effects of occupant seating posture during exposure to higher frequency multi-axis vibration associated with military propeller aircraft. Methods A Navy E-2C Hawkeye crew seat was mounted onto the Six Degree-of-Freedom Motion Simulator (SIXMODE). Six seat pan cushion configurations were tested during exposure to an E-2C vibration signal collected in the field1. Seat pan cushions 1 – 5 were used with the original E-2C seat back cushion. Cushion configuration 6 included seat pan cushion 5 with a prototype seat back cushion. Triaxial accelerometer pads were mounted onto the seat pan and seat back cushions to measure the vibration entering the human. Data were collected for seven subjects seated upright with their backs in contact with the seat (back-on) and not in contact with the seat (back-off). Spectral analysis techniques were used to analyze data at the two dominant frequencies associated with the propulsion system (propeller rotation frequency (PRF) ~18.5 Hz, and blade passage frequency (BPF) ~73.5 Hz). Overall accelerations were also calculated between 1 and 80 Hz. Vibration Total Values (VTVs) were calculated using the weighted seat pan and seat back (back-on only) accelerations and compared to the comfort reactions given in ISO 2631-1: 19972. Results In general, the highest accelerations observed at the seat pan occurred in the fore-and-aft (X) direction at both the PRF and the BPF for all cushions and both postures. The most pronounced effect was at the BPF in the X direction, where all configurations showed significantly lower seat pan accelerations than configuration 1 (original E-2C cushion) with the back-on posture. Configuration 5 was the exception with the back-off posture (Fig. 1A, Repeated Measures ANOVA, P<0.05). The most pronounced effect of posture occurred at the PRF in the X direction, where all cushion configurations showed significantly lower seat pan accelerations with the back-off posture (Fig. 1B). All configurations except configuration 2 showed similar VTVs as compared to Configuration 1 (Fig. 2, P<0.05). Configuration 2 tended to show the lowest weighted acceleration levels. The overall VTVs (back-on only, Fig. 2B) showed significantly higher accelerations as compared to both the back-on and back-off seat pan point VTVs (Figs. 2A &

Jan 6, 2006