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By J. E. Nesset, W. Zhang, J. A. Finch

Frother influences water recovery through control of bubble size and a chemical effect. De-coupling the two is necessary to establish the extent of the chemistry effect. A setup is described to give steady state water overflow rate (Jwo) along with measurements of bubble size into and on top of the froth. Arguing neither bubble size correlates directly with water overflow, a frother mass balance is solved to estimate the bubble surface area flux in the overflow (Sb0 ). The solution required measurement of frother concentration using TOC analysis and frother adsorption density using surface tension data. The relationship between Jwo and Sbo reveals the frother chemistry effect, quantified for discussion purposes by an equivalent water layer thickness.

Jan 1, 2009

Hydrometallurgy has a history of over 300 years with copper leachingand cementation having been exploited in Spain as far back as 1670.Since then, hydrometallurgy has become an integral, expanding branch of extractive metallurgy. This paper reviews major developments in hydrometallurgy over thepast century with emphasis on recent commercial developments and their impact on the mining and metals industries. The environment in which these developments has taken place has changed significantly in the past two decades and many factors, often non-technical, have emerged as constraints on the operation of existing plants and the expansion and development of new hydrometallurgical operations. Finally, a number of possible new developments that will shape thefuture of hydrometallurgy in the new millennium are discussed,particularly as they relate to the assimilation of technical advances in other areas of science and engineering. The impact of current trends in the education of hydrometallurgists and the provision of research in support of these future developments is also addressed.

Jan 1, 2001

By Renan da Silva Ramos, Caio da Silva Pontes, Leonardo Paraíba Cidrão, Alexandre Bestwina, Vilson Wenis dos Santos Belle, Gabriel Flintz Fraga Marques

A resposta a impacto balístico dos compósitos de alumina com polietileno de ultra alto peso molecular (PEAUPM) com diferentes concentrações relativas de alumina foi investigada. Os testes de impacto foram realizados em velocidade subsônica usando sistema de ar comprimido. As amostras de melhor desempenho foram as A00 e A90, sendo fraca a adesão interfacial entre a matriz de PEUAPM e as partículas de alumina. A profundidade de penetração (PP) em madeira MDF, protegido por um disco feito do compósito, diminuiu com o aumento da concentração de alumina no compósito.

Mar 1, 2019

By P. P. Andrieux

The recovery of the Zone G crown pillar, located between the bottom of the open pit and the top of the underground workings at the Raglan Katinniq Mine in Nunavik, started in the summer of 2008 and should be completed by the end of 2009. This article describes the rock mechanics-based approach implemented to design the recovery of this valuable block of ore. The stereophotography-based ShapeMetriX3D technique was first used to provide a comprehensive assessment of the various joint sets that comprised the pillar. Then, the statistical distributions obtained for the dip, dip direction, spacing and persistence of these sets were used in conjunction with the geometry of the large-scale faults present in the area to build and run a series of explicit rigid numerical models. Each of these models had a slightly different jointing geometry, randomly constructed from these statistical distributions. Incorporating in a properly formulated numerical model the variability of some of the input parameters has allowed the engineering team to assess in a rational and reliable manner the likelihood of success of the proposed mining method and sequence.

May 1, 2009

By F. F. von Glehn

There is no doubt that simulated ventilation networks must be adequately verified before they can be extrapolated and used for predictive purposes. There are two general approaches as to how the verification can be established and these are summarised as follows; The first approach is to measure all individual branches with trailing hoses or barometers to get individual pressure drop and flow per branch and then calculate individual resistance factors for input into the software. The simulator is run, checking that the output makes general sense (check some sensitivities if possible). The network is now considered as verified. The pressure drop to be measured is relatively small and thus it is inherent that the measured set of individual K factors will be imprecise no matter how much care is taken in the measurements and the resultant simulations will inherit the same problem. In the second approach, the network is assembled using estimated (Atkinson) K factors (based on physical features of airway, past experience and catalogued typical K factors). Only the main primary flow rates are measured and hence the relative distribution of the primary ventilation in the main airways is determined (probably about 10 off primary air flow measurements). Main critical pressure differentials at main and booster fans and across critical doors are measured (probably about 6 off primary pressure differential measurements need to be made). The simulator is run and the computer model is used to iterate and select an updated suite of K factors so that the flow balances and pressure differentials are correctly simulated (typically only 2 or 3 iterations are all that is needed). The network is now considered as verified. The pressure differences to be measured will be substantial in absolute terms and can be measured with high precision. Also, because only primary flows are measured, these will generally be measured at higher air speed points and hence improved relative accuracy. This leads to more accurate simulation results. This paper examines the advantages and disadvantages of the two approaches. 1 Background

Jan 1, 2009

By William M. Knuth

The objectives of this study were the evaluation of the technical and economical feasibility of utilizing color and color infrared aerial photography to satisfy some informational needs for pre-mine planning, mine progress monitoring, and reclamation monitoring. Seven aerial data collection missions were conducted within a two year period over strip mine sites in Pennsylvania. Scales of 1:6,000; 1:12,000; 1:24,000; and 1:48,000 were flown on the first aerial mission. The 1:12,000 was chosen as the optimal scale for the remaining six flights. An extensive literature and legislative review and discussions with strip mine operators identified the informational parameters that could possibly be obtained from aerial photography. Interpretability accuracies were evaluated for parameters in the broad categories of land use, soils, water, vegetation, and geology. Seasonal interpretation characteristics were noted for infrared photography. Man hours for photointerpretation and costs of aerial data collection were monitored closely and incorporated into a cost benefit analysis. Those parameters that could be mapped, identified, or measured with accuracies =75 percent were incorporated into a photointerpretation training manual. An additional analysis was performed to determine the applicability of the interpretation methodologies and results developed for Eastern sites to Western surface coal mining sites. In addition, a separate aerial photographic interpretation manual was produced during this contract. It is intended to be utilized by eastern and midwestern surface mine operators and regulatory personnel.

Jan 1, 1978

By H. Tomlinson

This circular is one of a series of papers on coal mining methods and costs which being prepared by the United States Bureau of Mines for the purpose of making available to those interested in the industry a knowledge of the mining methods employed, the places here mechanical and hand loading are practiced, and coat data on the several operations pertaining to the removal of coal from the working faces and its transportation to the tipple for loading into railroad cars. Mining costs are governed by the relative efficiency of the mining method employed. The method is selected for Its adaptability to the local natural physical conditions such as the nature and thickness of the coal bed, its dip, the character of the coal, and the thickness of the overlying strata.

Jan 1, 1930

By Natesa I. Jayaraman

This report describes recent improvements the Bureau of Mines made in the design of its shearer-clearer water-spray system for dust control on lonwgall shearer faces. The improvements were based on findings from a field survey of six mines and laboratory test results. The report in-cludes information on installation and use of the improved shearer-clearer system and describes a field installation and 3-week underground test of the system. The improved shearer clearer, like its predecessor, reduces dust concentrations in the shearer operator's walkway by splitting the airflow on the upwind side of the shearer and confining the dust cloud to the face side of the shearer. The improved shearer-clearer system utilizes more practical-mounting locations for the water sprays and requires less water consumption. In the underground test, the improved system maintained the clean-air split in the walkway up to 40 ft downstream from the shearer. To further improve dust suppression, cooling-water manifolds were relocated into the loading zone. The laboratory and underground tests showed that the improved shearer-clearer system and the techniques described can significantly reduce the respirable dust exposure of shearer operators from shearer-generated dust.

Jan 1, 1985

By Luis Maldonado Zorrilla

El consorcio minero Horizontes (La Libertad, Perú) contiene un yacimiento de rocas intrusivas fragmentadas y alteradas por acción tectónica, que son dífíciles de controlar ante las fuertes convergencias que dañan las labores. Por tal motivo, el sostenimiento de roca de la mina es un procedimiento difícil, lento y complejo que dificulta el trabajo de exploración y explotación del sub-suelo. En ese sentido, el presente trabajo señala una nueva técnica de reforzamiento del sostenimiento de labores principales y zonas de intersección donde se tienen problemas de inestabilidad y riesgo para el personal y equipos a través de inyecciones a presión de un líquido o suspensión (resinas) en las labores subterráneas muy inestables para rellenar los vacíos o discontinuidades del macizo rocoso como las fallas geológicas, diaclasas, juntas, contactos y oquedades.

Feb 1, 2016

By using knowledge-based technology to create a Virtual Mining Enterprise and integrating it with existing technical and financial computer systems, a gold mining company has been able to reduce the time taken to produce a mine plan from 14 weeks to less than one week. Typically, the mine planning process requires circulating and managing large amounts of information. Even with the use of computers in todayÆs business, this is often still a manual process involving file transfers and individualised spreadsheets. Mine planning also involves understanding and managing large quantities of complex and interrelated variables. Added to this is the ever changing dynamics and constraints associated with the business of mining. These issues not only hamper the planning process but also question the validity and usefulness of the mine plans being generated. By integrating the information and knowledge of the numerous departments involved in mine planning into one core Knowledge Base - so called æone version of the truthÆ, - mining companies are able to overcome these pitfalls experienced in traditional planning methods. Once set up, the Knowledge Base creates and runs a virtual mining enterprise with which to visualise and test various scenarios of mining, business and logistical activities. The final output is an optimised enterprise-wide plan with clear and detailed instructions for each of the divisions of the company.

Jan 1, 2000

By C. J. Cohen, L. A. Dahners

"SUMMARYA method has been developed for surveying, drill holes without lowering into the hole any surveying equipment other than an etch tube. The orientation of the rods at the collar of the hole is maintained as the etch tube is lowered. The attitude of the etch ellipse in depth with respect to the rod orientation at the collar can then be observed. This relationship permits the bearing of the hole in depth to he calculated. The rod orientation is maintained during the lowering by means of a pair of alinement clamps. One clamp is fastened to the top of each rod as the rod is coupled and is removed when the alinement has been transferred to the other clamp at the top of the next succeeding rod. A particular advantage of this survey technique is that surveys can be readily made in magnetic country rock.PRINCIPLE OF THE TECHNIQUEAn axial lamina of the column of drill roes is the lamina in which one fiber would be the centerline of the rods. In the new survey technique, the rods are fed into the hole in such a manner that the axial lamina of each successive rod maintains its position at the collar of the hole. In depth, as the rods bend in following the drill hole, the axial laminae also bend. The lamina that was originally vertical will, in general, be tilted away from the vertical. The trace of this lamina is marked on the glass etch tube before the tube is lowered in the hole. The axial lamina that becomes vertical at the survey station is recognized as that axial lamina which contains the long axis of the etch ellipse. The angle between the lamina originally vertical and the lamina vertical at the survey station is thus measurable. When the vertical axial lamina at one survey station has been determined by the etch ellipse at that station, angle R between this lamina and the vertical axial lamina at the next survey station becomes measurable also. By moans of angle R, and dip angles D1 and D2 at the two stations, the change in bearing (z) of the drill hole between the two stations can be calculated."

Aug 1, 1944

Meeting of June 26, 1914.-The President was authorized to appoint Advisory Committees to co operate with the United States Bureau of Mines. The President announced the appointment of Edward H. Benjamin and W. C. Ralston as additional members of the Committee on Arrangements for the San Francisco meeting, 1915. H. T. Van Ells and Judd Stewart were appointed to represent the Institute on a joint committee of several technical societies to consider the standardization of graphical methods for the presentation of statistics. The President announced the appointment of H. Foster Bain to succeed Edward H. Benjamin, resigned, on the Committee of Management of the International Engineering Congress, 1915. The Secretary was authorized to issue a new circular advertising the sale of back Transactions and to sell back Transactions, bound in cloth, at a price of $35 for 46 volumes, provided sufficient orders were received to warrant the special binding. The sum of $177.50 was contributed to the San Francisco Local Section. Upon recommendation of the Committee on Membership, 70 Members, 4 Associate Members and 7 Junior Members were elected to their respective classes; there was also one change of status from Junior Member to Member.

Jan 8, 1914

By H. Hearnden

Whereas in the past, ladles were simply a means of transferring molten products from furnace tapholes to points of discharge be they casting pans or waste dumps, the ladle is now becoming a more integral and versatile piece of equipment in the pyrometallurgical plant. The drive behind this development is the need for continuous improvement in performance where better, faster and cheaper means remaining competitive in the global market. This paper will explore the technologies available for the rendering of a costly and otherwise cumbersome piece of pyrometallurgical equipment more efficient and versatile in adding value to the final product. Essentially it all revolves around heat and more importantly the loss of it when tapping. The common practice is to move the molten product to its point of discharge quickly with the minimum of interruption to prevent skulling and hence the cost associated with clearing it. The advances in Oxy-fuel burners, AC or DC ladle furnaces, converters, gas purging and high velocity, bath injection systems has increased the versatility of processes and enhanced the potential for adding value to intermediate products through down stream practices such as granulation and atomisation.

Jan 1, 2004

By C. W. Owings, L. D. Tracy

"IntroductionMany bituminous coal-mining companies have inaugurated extensive safety Programs, but the failure to have approved or permissible equipment or safe practice in only one part of a mine has resulted in disaster. The necessity of using only equipment bearing the U. S. Bureau of Mines approval plate is emphasized by the fact that many accidents are the direct result of carelessness on the part of trusted employees using non-permissible equipment. A concrete example is found in the case of an explosion on October 26, 1926, in a mine in the Pittsburgh district, Pennsylvania.Story of the ExplosionAt about 10 o'clock on the night of the explosion an examination was made in No 2 butt left and parallel off 7o. 14 north, and was found to be clear of dangerous accumulations of gas. (See figure). Several hours later a crew of two men brought a self-propelling rock-dusting machine within 50 feet of the face of Po. 2 butt parallel before they examined for gas. The machine operator found an accumulation of explosive gas about 18 inches from the roof. He began to wave his arms thoroughly mixing the gas and air. Undoubtedly a highly explosive mixture was created, and as the men attempted to run the machine back to fresh air an explosion occurred.The helper dropped to the floor and was burned about the face and wrists. The machine operator ran down the entry and was more severely burned about the face, neck, and arms. He later developed pneumonia and died. Both men reached the door in the chute between No. 14 and No. 15 north. A pumper, who had felt the rush of air, found the men and helped them to walk outside."

May 1, 1927

By Mazin Adnan

The 80m high dam at the Peribonka river in the Canadian province of Quebec was designed for the generation of 385 MW of hydro electrical power (Fig.1). The complex ground conditions required the employment of a variety of geotechnical construction methods stretched to limits never experienced before. Innovative grouting and trenching techniques were used for the construction of a plastic concrete cut-off wall down to a depth of about 116m, to cut hydraulic seepage through alluvial deposits forming the dam foundation. The bedrock where the cut-off wall is embedded forms a glacial gully with steeply sloped flanks, which created further challenging conditions. [ ]

Jan 1, 2008

By H. T. Kennedy, D. L. Flock

"The project described in this pa-per was undertaken to provide a more thorough understanding of the effect of contamination by drilling fluids on the electrical properties of porous systems. The basic work per-formed was filtration tests on both consolidated and unconsolidated sands and the determination of their resistivity profiles with the aid of screen-type electrodes spaced at convenient intervals along the core.Four drilling fluids were selected, ranging in resistivity from 447.0 ohm-cm. to •5.76 ohm-cm. The permeability of three unconsolidated and four consolidated cores, on which resistivity measurements were made, varied from 1,257 md. to 4,560 md. Five additional cores with permeabilities as low as 49 md. were tested to investigate the effect of permeability on the depth of invasion of drilling fluids.The effect of drilling fluid invasion on resistivity profiles was determined on cores containing brine only, and on those containing 80 to 90 per cent oil and 20 to 10 per cent brine. The study included measurements of (a) clay content of different sections of the core, (b) saturation of the invaded fluids and oil in different parts of the core, and ( c) changes in resistivity as a result of gravitational re-distribution of fluids and diffusion of electrolytes.The data showed that the resistivity of an invaded core is, as was expected, controlled by the resistivity of the filtrate, the resistivity of residual core water, the resistivity of the clay particles, and the amount and distribution of the filtrate, clays, residual oil, and brine. In most cases there was a significant increase in resistivity owing to the presence of clay solids which had invaded the core. The change in resistivity, as a result of the diffusion of salts, was substantial after a period of five hours. There is evidence in some cases that the residual oil and core water saturations of the unconsolidated cores, after substantial invasion, are very low, indicating almost complete displacement by invading fluid."

Jan 1, 1959

Gold rooms represent a high security area and preventing theft is a challenging task. Where gravity concentrates or high value unit intermediate products are present, particular and specific security procedures must be put in place. This paper describes the development and implementation which reflects best practice in gold room security. Procedures involving key holder systems, key locks, swipe cards and double locks preventing any one person having access to the gold room, including specific procedures for gravity gold concentrators, will be addressed. The use of monitoring and how to deal with alarms and potential hold ups will be reviewed. The use of cameras and archival DVD recorders is common in gold rooms. The use of electronic surveillance, movement detectors, seismic monitors and the two person policy and gold room entry procedures are described, including how to deal with visitors. The importance of confidentiality regarding smelting and gold pick-up days, plus strategies employed to minimise storing large quantities of gold on site will be presented. The role of metallurgical accounting in providing quality auditable information and the minimum standards of record keeping required is discussed. The role of the Gold Squad will be outlined. Regular auditing and risk analysis and several case studies are cited where security was deficient or improved.

Aug 1, 2010

By R. R. Seeber

(Pittsburg Meeting, March, 1910.) IN the copper-mining district of northern Michigan a fair-sized mine usually operates two or more shafts along the strike of the lode, these shafts being usually at least 1,000 ft. apart. The tonnage to be hoisted from each shaft is large-from 13,000 to 25,000 tons per month. The hoisting-engines used are generally steam-driven, non-condensing, duplex engines with Corliss valves, supplied by steam from separate boiler-plants where the distance between shafts is great. In an attempt to centralize power-plants and secure central-station economies, the Winona Copper Co. installed an electric hoist of the Ilgner type, with Ward Leonard control. A brief description of this plant has already been published.1 The only point of variation from the simple Ilgner set lies in the connection of two generators to a single induction-motor by flexible couplings. These generators serve motors which operate hoisting-drums at separate shafts, viz., No. 4 shaft, Winona, and No. 1 shaft, King Philip. , The hoist for No. 4 shaft, is about 1,700 ft. from the power-plant, and in this building the motor-generator set is placed. No. 1 King Philip hoist is 1,500 ft. from the motor-generator set. The equipment of the motor-generator set is as follows: In the middle of the set is a 12-pole, 450-h-p., 600-rev. per min., 2,080-volt, three-phase, 60-cycle, variable-speed induction-motor, connected on each side to a 20-ton fly-wheel which is 10 ft. in diameter, and to a 6-pole, 170-kw, 575-volt, interpole, direct-current generator. On each side of the shaft is placed a separate exciter, which delivers current at 125 volts. The lubrication of the four main bearings that support the fly-wheels * Presented also, by mutual agreement, at the meeting of the American Institute of Electrical Engineers, New York, N. Y., Mar. 11, 1910. Engineering and Mining Journal, vol. lxxxviii., No. 3, p. 110 (July 17, 1909).

Sep 1, 1910

By Christophe Bragard

The Los Angeles Metro Eastside Extension light rail project included a 1.5 mile underground segment, which consisted of twin 18'?10" ID tunnels, bored with two EPB-TBMs. One of the major project challenges after the completion of the bored tunnels was the excavation of six cross passages within alluvial geology below the water table and with low ground cover. Sequential excavation methods were employed and this paper details the design, ground treatment, support measures, and construction methods used to mine these cross passages beneath the congested urban streets of the City of Los Angeles.

Jan 1, 2008

By Márcio Zamboti Fortes

A alguns anos os setores residencial e industrial tem se deparado com mudanças de paradigmas que tangem a necessidade de melhorias em suas atividades, com o intuito de desenvolver processos com menor impacto ambiental, sustentáveis e com eficiência energética, objetivando reduzir o consumo de energia elétrica. O uso de tecnologias baseadas em fontes renováveis para a geração de energia elétrica, tais como a solar e a eólica, tem apresentado-se como uma alternativa a ser implementada por estes setores para atender às exigências do mercado, se beneficiando da difusão da tecnologia e uso destes equipamentos, para a consciente utilização da energia elétrica. A instalação e avaliação de novas fontes de geração de eletricidade estão sendo desenvolvidas pelo projeto Cidade Inteligente de Búzios através da implantação de painéis fotovoltaicos e aerogeradores de pequeno porte em unidades consumidoras residenciais, comerciais e industriais e alguns resultados estão apresentados neste texto.

Sep 25, 2017