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By P B. Hills

Increasingly over the past couple of decades, the importance of understanding the in situ stress regime in underground hard rock mines has become accepted by all. Providers have responded to this requirement and various techniques for undertaking the measurements have been honed while others have slipped from use. It is a simple, though not inexpensive task to engage a provider to undertake the require measurements, and a comprehensive report will ensue. So, what has actually been obtained? What should the geotechnical engineer do next? What tools are necessary to do so? Regardless of the method of measurement, the report will describe the location of the measurement site and describe the basis of the methodology used in undertaking the measurements and a log of the measurement program. Finally, it will include the results, which should incorporate the normal and shear stress components of the full stress tensor. Ground control management plans (GCMP’s) and stress summary reports and spreadsheets prepared by site geotechnical engineers always include the magnitude, trend and plunge of the principal stresses. Remarkably few site-based summaries include the full stress tensor. This is a significant gap as the full stress tensor is vital for any further data manipulation. However, without the algebraic tools to undertake those manipulations, their value is diminished. This paper seeks to provide a checklist of ideas to be considered. It provides commentary on the options available to dissect the stress measurement report and ensure that the maximum possible value is derived from it. The manipulation and presentation of component stress data is also discussed. The various methods of stress measurement are not the focus of the paper but some of the strengths and weaknesses of them over which the site geotechnical engineer has some control, are highlighted.

Nov 29, 2022

By O. C. Gaspar

The mineralogical and textural characteristics of the volcanogenic massive sulphide ores from the Aljustrel and Neves-Corvo deposits have been studied by ore microscopy techniques since 1977. Several ore types have been recognized, and the ore paragenesis, ore textures, and behaviours of different ore types during grinding and concentration processes, have been determined. An ore classification was established for use in metallogenetic studies, ore reserve calculations, selectivity during mining, and control of the ore beneficiation processes. In addition, an empirical method was developed for supplying, on time, the qualitative and semi-quantitative information needed for processing the Aljustrel ores and for optimizing the Neves-. Corvo copper and tin concentrators.

Jan 1, 1991

By Lucas Sanches Magalhães

A utilização de resíduos industriais é dificultada, na maioria das vezes, pela presença de determinados elementos, como por exemplo, o ferro, justificando assim a sua remoção. Dentro deste contexto, o objetivo deste trabalho foi estudar a sulfatação de um resíduo proveniente da flotação de um minério de ferro e subsequente lixiviação deste resíduo sulfatado. A composição mineralógica da amostra inicial foi obtida por DRX e MEV sendo possível identificar quartzo (SiO2), hematita (Fe2O3) e muscovita (KAl2Si3AlO10(OH,F)2). De acordo com a análise química, os teores dos elementos principais foram: Fe (12,65%), S (4,02%), e Al (0,62%). Na sulfatação, realizada à 250ºC durante 4 horas, foi estudada a influência da relação ácido sulfúrico/amostra (0,1:1; 0,2:1; 0,7:1; 0,8:1; 0,9:1 e 1:1) na extração do ferro. A lixiviação foi conduzida com 5% de sólidos do material sulfatado, sendo avaliada a interferência da temperatura de lixiviação (25°C e 90°C) e do tempo de duração dos ensaios (15min, 30min, 60min, 120min, 180min e 240min). Pelos resultados obtidos observou-se que o tempo de lixiviação foi um parâmetro insignificante. A máxima extração de ferro foi encontrada sulfatando o resíduo na relação ácido/amostra 1:1 e posteriormente realizando a lixiviação deste resíduo sulfatado a 90°C por 30 minutos, alcançando 85,64% de extração do Fe.

Aug 17, 2017

By Abrahan Barriga

The present study demonstrates the feasibility of the ultrafine grinding and atmospheric leaching process applied to refractory gold concentrates from Salave Project located in northern Spain. At bench scale, it was found acceptable sulfide oxidation was about 84-85% and CIL gold recoveries between 95-96% applying specific energy consumption between 30 and 60 kWh/t during ultrafine grinding. The atmospheric oxidation of the sulfide concentrate was controlled between pH 4.4 and 4.8 with a mixture 90/10 of CaCO3/NaCO3 with residence time of 48 hours for the atmospheric oxidation and 30 hours residence time for the CIL process.

Sep 30, 2022

By C. A. Hartnagel, D. H. Newland

Most of the petroleum produced in New York State is obtained by flooding; that is, water drive. No important oil fields have been developed during the past 30 years, nor does there seem much hope that the productive oil areas will be substantially enlarged in the future. There is some prospect that additional supplies may be obtained by deeper drilling, but deep tests for gas to the Oriskany sandstone in some of the oil-producing areas have been without results so far as any discoveries of oil are concerned. Although the flooding method had been made legal in 1919, and some floods had been in operation previous to 1921, that year marks the beginning of a rapid increase in oil production by the new method. The flush production of oil in New York was in 1882, shortly after the discovery of the Richburg pool in Allegany County. The oil production in that year amounted to 6,685,000 bbl. The 1937 production of 5,478,000 bbl. was the largest since the flush production of 55 years ago. The effectiveness of water-flooding for increasing oil production from the old New York fields is shown in Table 1. Table 1.—Production of Oil in New York since 1921 Year Barrels Year Barrela 1921 988,000 1929 3,377,000 1922 1,000,000 1930 3,647,000 1923 1,250,000 1931 3,363,000 1924 1,440,000 1932 3,508,000 1925 1,695,000 1933 3,181,000 1926 2,242,000 1934 3,804,000 1927 2,603,000 1935 4,236,000 1928 3,377,000 1936 4,633,000 1937 5,478,000 The area of the New York oil fields is about 60,000 acres. It has been estimated that not over one-fourth of the area is being flooded. Very little of flooded territory has ceased to produce. Some leases flooded by the early, less scientific methods are being again subjected to the water

Jan 1, 1938

By Ping Zhang, Shahram Mozaffari, Andreas Ylmefors

The risk associated with mining induced seismicity and the related rock bursts has become one of the major threats to the safety and sustainability of mining at the Kiirunavaara mine. The causes of mining induced seismicity at the Kiirunavaara mine are very complex and have affected our understanding on the source mechanisms of seismicity and further the mitigation of the seismic risk. Detailed analysis of historical mining induced seismicity at the Kiirunavaara mine was conducted. The focus of this analysis was placed on the classification of large seismic events and the evaluation of the influential factors on the classified seismic events. 145 events with local magnitude larger than 1.5 that occurred between January 1, 2011 and March 31, 2021 were analyzed. For this analysis, seismic events located in the hanging wall were not included, as these have not been observed to cause large damages to the mine itself. It was found that the magnitude of the events had good correlation with the stress change in relation to the production location. The seismic events were classified as mining-front associated, ore-pass associated, mining-front and ore-pass associated and others, according to their hypocenter location. Most of the mining-front associated events, concentrated around the production levels and slightly above and below them, generally correlated with shear cracks, and most of them occurred when the ore flow between two production levels started. The numerical modelling showed that slip of the geological discontinuity, due to unclamping between hanging wall and footwall, could be the major causative mechanisms, which further supports this finding. The ore-pass associated events are located close to the ore passes. Large seismic events located between ore passes have the source mechanism of both fault-slip and non-shear, but events located at the outer side of ore passes were all fault-slip type. By checking with the ore pass scanning data, it was concluded that the most of the events located between ore passes could be pillar bursts. An elastic core concept has been then used to define a critical pillar width. The paper is not intended to be prescriptive but rather to initiate discussion of the possible classification of seismic events at the Kiirunavaara mine and to present new perspectives of the causes of the seismicity for improving the present seismic risk management.

Apr 26, 2022

By André Xavier, Edim Bahamonde

En las últimas décadas ha habido un aumento del otorgamiento de concesiones mineras por parte del Estado peruano; sin embargo, paralelamente se ha incrementado el número de conflictos sociales. Ante este panorama, es necesario promover la participación de las comunidades a través de la conformación de comités de monitoreo ambiental participativo, como una herramienta que fortalezca las relaciones de confianza entre las empresas mineras, las comunidades y el Estado, de manera que se genere progreso en la línea de los Objetivos de Desarrollo Sostenible. Este estudio presenta los casos de los comités de monitoreo ambiental participativo de Orcopampa (Arequipa), Juprog (Ancash) y Mallay (Lima), como referentes de buenas prácticas que aportan al mejoramiento de la prevención de conflictos socioambientales.

Sep 20, 2019

By Robert Stefanko

The Federal Coal Mine Health and Safety Act of 1969 had far reaching effects upon many aspects of mining, ventilation being no exception. In this paper, good ventilation procedures are briefly reviewed, and attention is focused on the changes brought about by the new Act. By way of illustration the ventilation system for a typical Pittsburgh Block system is developed and the requirements of the fan determined. This is then solved by an available computer program, and the application is evaluated. Figure 1 represents a projected system for a coal property 1 by 3 miles in plan at a depth of 1000 feet with a coal thickness of 6 feet and desired daily tonnage of approximately 7200 tons on a two-shift basis. Only one half of the mine is shown (north area) with a mirror image mining arrangement to be developed concurrently for the south area. Six working units are projected, three in each area, one on pillar extraction, another developing panel entries and a third on main entry development. A two-split system is used for each working section so that the continuous miner and bolting crews each have a separate split of air, and no equipment need pass through a line brattice. The old requirement of 6000 cfm at the last open crosscut has been increased to 9000 cfm, and for the first time a minimum quantity (3000 cfm) is stipulated at the face thus requiring either line brattice or an auxiliary fan. With the respirable dust requirement limited to 3 mg/m3, the use of a blower system is precluded and exhaust systems are virtually the only choice. Maintaining the line brattice within 10 feet of the working face at all times as required by the new law has a definite effect on the mining cycle and is most difficult at best. In the highly gaseous Pittsburgh seam located in south-western Pennsylvania and northern West Virginia quantities of 20,000 cfm per split are not uncommon to maintain the methane percentage below the required l%

Jan 1, 1972

By John A. Herbst

Plantwide control of mineral processing operations has long been sought for its potential benefits. These benefits include minute-to-minute optimization, reacting to disturbances in ore characteristics and equipment status as they happen and the coordination of all unit operations in pursuit of the highest performance level. However several difficult challenges have kept us from fully realizing those benefits. One of these challenges has been to provide fairly complete quantitative descriptions of Unit operations to account for critical interactions within and 'between unit operations. In some cases we understand the physics and chemistry very well and can incorporate that 'knowledge into phenomenological models. In other cases our knowledge is incomplete, so we must rely on other forms of knowledge such as fuzzy logic or neural nets. Another challenge to be met has been to simultaneously compute a large number of manipulated variables. In the past this challenge was met by optimizing only unit-by-unit, rather than on a global basis to significantly reduce the number of variables. In this paper, a procedure that globally optimizes one or two important variables is outlined. This procedure comes much closer to true plantwide optimizing control while remaining computationally feasible. Finally, another major challenge is to choose a meaningful global objective that can be calculated With the models and can be effectively optimized. Financial goals seems to be the objectives of choice. This paper discusses recent progress In overcoming the challenges and illustrates a promising approach which is being pursued at :Mexicana de Cobre's 'La Caridad copper ore concentrator. At M de C, advanced ,control strategies have been 'installed one at a time in the crushing, grinding and flotation sections. During this period, the throughput of La Caridad, Mexico's largest copper concentrator, 'increased from 76;000 tpd to 90,000 tpd. Plantwide integration is expected' to gain an additional 3% improvement in profitability.

Jan 1, 1996

By David A. Campbell

There has been a long history of ironmaking on the North East coast of England centered around the River Tees. The industry developed here because of the availability of good coking coals to the North in Co. Durham, and the discovery in 1851 of ironstone in the nearby Cleveland Hills, South of the .River. Cleveland ironstone is relatively poor in quality, with an iron content not exceeding h% and high proportion of sulphur and phosphorous. The iron exists in chemical association with alumina and silica, and physical beneficiation processes involve a serious loss in iron unless the upgrading is limited, when the economics of the process become doubtful. Over the years, richer foreign ores have replaced the local ironstone, and the last operating mine was closed in 1964.

Jan 1, 1982

By L. A. Baker

The presence of goethite in a hematite ore has been shown to strongly affect the time of heating to the firing temperature. The investigation of spalling of single pellets and of packed beds has enabled free water and goethite spalling to be identified as separate phenomena. In addition, it has been shown that even for an 18 inch deep bed of green balls the free water and goethite drying periods can be considered separately. Based on this observation, a method of predicting production rate and hood temperature profile is presented. The method required knowledge of the ore goethite content, ore grind and the green pellet bulk density. Laboratory results were found to be in good agreement with actual plant practice and have led to improved process performance.

Jan 1, 1972

By Robert W. McKibbin

The Bureau of Mines conducted laboratory tests to determine the slurry transport and deposition properties of coal waste. A 188.5-ft pipe test loop was constructed with instruments to measure density, flow, and power and discharge, suction, and differential pressures. A 20-ton ample of Western coal waste was crushed and screened to 100 pct minus 1/2 in. Eight loop tests using this graded waste were run at slurry densities ranging from 1.15 (25 wt-pct solids) to 1.46 (60 wt-pct sol-ids) 0 The resultant friction-'pressure gradients ranged from 0,06 to 0.24 ft of water per foot of 4-in standard steel pipe. Particle-size degradation was significant.. In a typical loop test lasting 25 min, the minus 200-mesh fraction increased from 19 pct to 34 pct. Deposition tests showed that without the use of a flocculant, the slurries would not dewater when left to stand for 1 week. With flocculant, additional water was releas2d; however, the settled slurries remained thixotropic. Further testing is necessary to determine their suitability for use as backfill material in active mines.

Jan 1, 1983

By S Q. Zhao, J H. Wei

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Xitieshan lead-zinc deposit is located in the north margin of the Qaidam Basin, Qinghai Province, China. It is one of the largest massive sulfide deposits in China and is supposed to be of the sedimentation-exhalation (SEDEX) type. Based on the main ore mineral and sulfur isotopic compositions in sulfides found in the wall rock, the S of the deposit is considered to originate from the mantle, but the fluid potentially mixed with sea water during the hydrothermal circulation exchange. The study of lead isotopes shows that the metallogenic material is characterised by the mixture of orogenic and upper crust sources. The lead isotopic signature of the wall rock is similar to that of the ore, which shows synsedimentary characteristics. According to the composition of the rubidium and strontium isotopic signature, the value of 87Sr/86Sr is lower than the average value of that in the crustal rock, which is larger than that of the mantle. Hence, the metallogenic materials of this deposit mainly originate from the crust, which is related to materials of volcanic rocks activation and migration of the deep hot circulating water. The process of the metallogenic fluid circulation shows continuous interaction with crustal material and lead to continuous enrichment of the ore forming fluids. From the study of the fluid inclusion microthermometry of the ore and the associated minerals combined with the C, H-O, Si isotopes, it is believed that the metallogenic fluid is mainly coming from the mantle or the deep magma chambers. The rising deep fluid then mixes with the sea water. The carbon dioxide escaping and mixing with sea water during the hydrothermal exhalation process leads to the rapid precipitation of the hydrothermal fluid to deposit metal. That is proposed as the principal formation mechanism of the Xitieshan deposit. Further studies are proposed, including obtaining geochronology data from this deposit.CITATION:Zhao, Z X, Wei, J H, Liang, S N and Zhao, S Q, 2015. Advances in research on metallogenic mechanisms for the Xitieshan sedimentation-exhalation lead-zinc deposit, Qinghai Province, China, in Proceedings PACRIM 2015 Congress, pp 487–494 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By John Ward Smith

Variations in specific gravity of oil retorted from oil shales of the Eocene Green River Formation in northwestern Colorado were evaluated statistically, demonstrating that these variations are very strongly associated with stratigraphic position and less strongly but still significantly associated with geographic location. Specific gravity of oil retorted from these oil shales apparently varies with the carboxyl group content of the oil shale's organic matter. Higher temperatures accompanying increasing depth of burial probably progressively decarboxylated oil shale's organic matter producing the decrease of oil specific gravity associated with deeper stratigraphic position. The geographically associated oil-gravity variations were probably produced by regional variation in the original thickness of late Cenozoic extrusive rocks once overlying the Green River Formation.

Jan 1, 1966

By Margaret R. Egan

The Bureau of Mines experimentally burned Pittsburgh Seam coal and other combustible materials found in mines in order to obtain a better knowledge of their emission products. These experiments were conducted in the Bureau's intermediate-scale fire tunnel, which simulates environ-mental conditions in underground mines. Smoke characteristics, gas concentrations, mass loss, and ventilation were measured. From these values, heat-release rates, particle sizes, obscuration rates, combustion yields, and production constants were calculated. This information was sought as part of a comprehensive study of combustible materials that will ultimately advance the design of more efficient fire detection and suppression systems. The coal combustion measurements presented in this report, together with previous analyses of wood and transformer fluid fires form a data base by which future studies of other mine combustibles can be compared.

Jan 1, 1987

By K. R. Koch

Although some of the platinum(II/IV) and rhodium(III) chemistry is considered ?old? and well-known, the application of modern multinuclear NMR spectroscopic methods to this chemistry in solution reveals new details about their rich and relevant solution chemistry. In this paper we will briefly illustrate that the highly-sensitive 195Pt NMR shielding is an excellent probe to explore aspects such as solvation, ion-pairing, and the hydrolysis chemistry of inter alia [PtCl6-n(H2O)n]n-2 (n=0-5). Moreover the novel use of 35Cl/37Cl and 18O isotopes effects as unique NMR ?fingerprints? leading to a new and unambiguous method of chemical speciation of the numerous possible PtII/IV and RhIII complexes present in halide-rich aqueous solutions. In the case of Rh(III) chemistry a new, direct speciation distribution diagram has been established for [RhCln(H2O)6-n]3-n complexes (n = 3-6) in HCl solution at 292 K with these methods.

Jan 1, 2012

By Alexandre Carvalho Martins

Este trabalho tem por objetivo apresentar o projeto de modernização do sistema de supervisão da Mina, Britagem e Concentrador I da unidade de Germano da Samarco Mineração. A principal motivação que levou a Samarco a modernização do sistema de supervisão foi o fato da aplicação atual já estar saturada, dificultando novas implementações, além de já apresentar limitações no diagnóstico de defeitos e intertravamentos. Na solução implementada, destaca-se a estratégia de virtualização adotada, o sistema para cadastramento e modificação em tempo real das entidades do CLP e as funcionalidades para gestão de alarmes.

Jul 30, 2018

By Thomas O. Llewellyn

This U.S. Bureau of Mines (USBM) report presents a concise review on sources, processes, supply, and historical use patterns of domestic cadmium. It also covers a preliminary estimated cadmium material flow for the year 1989. This preliminary study contains information on cadmium and cadmium-bearing products in the United States. The data in this report were obtained from both published and/or unpublished sources of information. However, in order to estimate the fate of cadmium in each operation or application stage, some assumptions, judgments, and correlations were made by the USBM in an attempt to determine the material flows losses.

Jan 1, 1994

By Sérgio de Azevedo Penchel Júnior

A Votorantim Metais possui dois Smelters de Zn situados no estado de Minas Gerais, Brasil, um na cidade de Três Marias e outro na cidade de Juiz de Fora. A unidade de Juiz de Fora tem se caracterizado ao longo dos anos pela mudança de estratégia no que diz respeito a obtenção de matérias-primas, buscando oportunidades em materiais secundários ricos em Zn, em substituição ao concentrado de Zn, tornando-se ao longo do tempo cada vez mais uma unidade recicladora. O cemento é um material gerado na Hidrometalurgia do Zn, mais precisamente na etapa de purificação, e é composto basicamente por Zn, Cu, Cd, Co, Pb e Tl. A solução purificada, produzida após esta etapa é direcionada a eletrólise para produção de zinco eletrolítico. Atualmente em Juiz de Fora, todo cemento gerado é destinado a uma área específica da hidrometalurgia para seu tratamento e recuperação de Zn e Cd. Os demais metais são perdidos e dispostos na barragem de rejeitos. Na planta de Três Marias não existe área específica para tratamento desse material, e dessa forma, todo ele é estocado em depósito especial. O objetivo desse estudo é avaliar e propor uma rota alternativa de processo que permita uma maior recuperação de metais dos cementos de TM e JF, utilizando os ativos da planta de tratamento de cementos de JF levando dessa forma a redução da geração de resíduos enviados para as barragens de uma forma economicamente viável.

Aug 17, 2017

8053. Andreev, B. A. Zakashanakii, M. S., Samsonov, N. N., and Fotiadi, E. E. A Textbook of Gravitational -Surveying, (in Russian). Gosgeolizdat, Moscow-Leningrad, 1941, 432 pp. This textbook was written at the suggestion of-the faculty of geophysical exploration of the Leningrad Mining Institute. It contains two parts: (1) Theory and technique, and (2) Applications to geology and exploration. The features bringing; the text up-to-date include: (a) Description of the principal modern gravimeters; particular attention to the method of simultaneous oscillation of 4 pendulums; (b) discussion of the aperiodic oscillation of torsion balances; outline of the construction of variometers Z -20 and Z-40; (c) material for aid in interpretation, such as reference-charts, formulas with their derivation, atlas of theoretical curves, and examples of interpretative calculations; (d) considerations in the planning of surveys and the densities of various rocks; and (e) detailed analysis of significant examples. The text is provided with a bibliography, V. S.

Jan 1, 1946