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By Marcos Meyer

A pelotização é um processo de aglomeração com objetivo de agregar valor aos finos de minérios de ferro (pellet feed). A partir de 2010, a mina de Brucutu situada no Quadrilátero Ferriferro (QF) passa a ser a maior fornecedora de matéria prima para as plantas de Tubarão / Vitória-ES. O estudo avaliou a performance industrial de duas misturas com alta participação de minério de Brucutu, acima do padrão utilizado na usina de pelotização. Os minérios compostos nas misturas foram caracterizados por análise química, física, mineralógica e microestrutural. O desempenho operacional mostrou superior à mistura padrão utilizada para a produção de pelotas para redução direta, permanecendo com os parâmetros de qualidade consoantes com as especificações do produto final. O conhecimento das características geometalúrgicas destas misturas com minério de Brucutu em maior escala foi de suma importância para adequar o processo e custo das principais operações unitárias da planta envolvida (moagem e forno).

Aug 1, 2018

By Jacob Masliyah, Zhiang Zhou, Tshitende Kasongo, Jianjun Liu, Zhenghe Xu, Jeawon Choung

"Slime coating is a recognized challenge in fine particle flotation, not only in decreasing recovery, but also in reducing the selectivity and hence froth quality. In this presentation, a novel method based on electrophoretic mobility distribution measurement to study slime coatings is described. By measuring electrophoretic mobility distribution of individual minerals and their mixtures, the interactions between these minerals can be evaluated.For illustrative purposes, a model system of fine coals, or oil sands with two different types of fine clays was studied. Flotation tests showed a significant decrease in coal (bitumen) flotation recovery with montmorillonite but not with kaolinite clay addition. When electrophoretic mobility distribution of a fine coal/montmorillonite clay mixture was measured, a single modal zeta potential distribution was obtained, in contrast to a bimodal distribution for fine coalkaolinite clay mixture. This finding suggests a stronger adhesion of montmorillonite than kaolinite clays on fine coal surfaces. In the case of bitumen, the bimodal zeta potential distribution was measured for the mixture of bitumen emulsion and kaolinite or montmorillonite, indicating a weak attraction of the clays by bitumen. In the presence of calcium, however, a single modal zeta potential distribution was obtained in the mixture of bitumen emulsion with montmorillonite but not kaolinite clays. These findings are in excellent agreement with bitumen flotation results, demonstrating that the electrophoretic distribution measurement is a powerful tool to study slime coating phenomenon in a complex fine particle flotation system."

Jan 1, 2002

By Vantuil Manoel Thebas

A automatização do laminador Machine duo reversível de 8 toneladas passa pela determinação da força de laminação em seus cilindros durante processo de deformação da chapa metálica não ferrosa, o que se faz pela medição direta da força nos cilindros do laminador através de um sensor de força ou pelo uso de modelos matemáticos aplicados ao processo de laminação das ligas metálicas. O presente trabalho tem por objetivo o estudo dos modelos de Orowan, Ekelund e Bland & Ford aplicados à predição da carga de laminação de ligas metálicas não ferrosas. Amostras em barras chatas extrudadas com 6,35 mm (14/') de espessura da liga de Alumínio 6063-T5, com 300 mm de comprimento e 50,8 mm (2’) de largura, foram laminadas. Suas dimensões finais foram obtidas por uma escala de medição e paquímetro universal, sendo os dados tratados por rotinas computacionais especificamente desenvolvidas para a implementação dos modelos matemáticos citados. Os resultados deram conta de que a implementação dos modelos de Orowan, Ekelund e Bland & Ford através de rotinas computacionais podem ser muito úteis na predição da carga de laminação de ligas metálicas não ferrosas.

Aug 8, 2018

By Syd Peng, W. B. Guo, F. Du, L. Yang, J. Yw. Cheng

The annual ICGCM China was initiated in 2014. Up to 2023, ICGCM China has been held 9 times. In the 9 conferences during the past 10 years, about 559 papers in 17 topical areas were presented and attendance ranged from 200+ to 400+ each conference. The 42nd ICGCM China was held in Xiangtan, Hunan, China, 10/20–10/22/2023. There were 86 papers presented in 26 topical areas. In addition, an MS and PhD Research Forum was held concurrently with 36 papers presented by MS and PhD candidates in mining engineering from 8 schools. The conference plays an important role in cultivating advanced degree student talents. In this paper, all 559 papers reviewed previously were summarized. In addition, the 42nd ICGCM China is used to illustrate the current and future development trends of coal mine ground control in China. It summarizes the 122 papers (including 36 MS and PhD forum papers) grouping into, and in terms of, 26 topical areas. In addition, its unique and innovative subject areas, short summary of developments as well as conference strengths and shortcomings will also be presented.

Jun 25, 2024

By C. Ringas

Pipelines are used extensively in industry to convey various products. Internal corrosion of pipelines can lead to perforation and leakage of the product. A growing problem, not often accurately recognized, is internal corrosion of pipelines caused by bacteria. Microbiologically-induced corrosion (MIC) refers to corrosion caused by a variety of micro-organisms. This form of corrosion is not widely recognized in many industries, although it is widespread and causes many corrosion problems in pipelines, both internal and external. Sulphate-reducing bacteria (SRB) are responsible for the bulk of the corrosion problems caused by MIC. Corrosion caused by SRB is found extensively in water pipelines conveying raw, potable and waste water, as well as in pipelines conveying slurries. This problem also occurs in pipelines conveying crude oil. This paper describes internal corrosion problems of slurry pipelines caused by bacteria and outlines mitigation methods to improve slurry pipeline integrity, thereby extending the life of such pipeline

Jan 1, 2007

By Douglas Marcel Quatiabara Sander Libardi

O optical televiewer (OPTV) é um dispositivo de perfilagem geofísica que produz uma imagem contínua e orientada da parede do furo de sondagem. Neste trabalho, foram selecionadas perfilagens realizadas em furos de sondagem executados em duas minas que fazem parte da ‘Megaestrutura Gandarela’, localizada na porção centro-norte do Quadrilátero Ferrífero, Minas Gerais. As imagens geradas pela sonda OPTV desempenham um papel auxiliar em campanhas de exploração mineral e também na aquisição de informações geotécnicas. Os dados coletados foram retirados das filmagens realizadas a partir da sonda OPTV e do geoposicionamento oferecido pela sonda. A marcação das estruturas nas imagens de OPTV, a correção da deriva magnética e as análises cinemáticas foram realizadas nos softwares WellCad e Dips. O principal objetivo deste trabalho é efetuar a análise cinemática feita a partir de estruturas marcadas em imagens de OPTV e compará-la com a análise cinemática efetuada a partir das estruturas identificadas no mapeamento geológico estrutural nas minas. O estudo mostrou que as estruturas marcadas com OPTV reproduzem satisfatoriamente as observações do mapeamento geológico estrutural.

Oct 30, 2017

By M. Leslar

Slope monitoring has been an important issue in static terrestrial lidar for some time. Several solutions for monitoring the progress of a slide have been devised over the years. All of these solutions have required users to be in the field operating the lidar equipment. This paper presents a new system developed using the Optech ILRIS-HD or ILRIS-LR lidar and the scripting language of PolyWorks to produce an autonomous slope monitoring system. This system has proven invaluable in detecting and alerting mine workers to potential danger within their mine sites. It has already been deployed in two mine sites and is scheduled to be installed at a third.

Feb 27, 2013

By N. Som

The pile capacity in cohesive and granular soils depends on a number of parameters. The values of these parameters as recommended by Indian Standard Code of Practice vary over wide ranges. A designer often finds it difficult to select appropriate values of these parameters for realistic estimate of a pile capacity. The present paper makes a critical review of the values of the parameters given in Indian Standard Code of Practice and suggests a realistic approach to selecting them in the light of recent research.

Jan 1, 1996

By P. Mousset-Jones

The USBH Mining Systems and Ground Control Generic Research Center funded a project leading to the improved planning of airflow and refrigeration in underground mines experiencing hot working conditions. The project was broken down into approximately five phases: 1. Visiting some of the known hot mines in the U.S. and sending out a questionnaire to determine other mines which might be experiencing hot working conditions in the future. 2. Choosing two mines in which to conduct measurements to determine the insitu rock thermal conductivity and diffusivity, and comparing these values with laboratory determined values. 3. Investigating computer programs available for mine climate simulation, and testing these programs with case study examples from the two mines where the rock thermal properties were measured. 4. Considering improved ways of estimating the wetness factor and experimenting with the use of heat flux meters to more directly measure the rock heat inflow into the airstream. 5. Applying the results of these investigations to simulating the climate for future mine development and production areas at the two- mines. The project is approximately two thirds completed. At the time of writing, the insitu measurements at one of the mines are still being recorded. This paper will be describing the procedures and results of the insitu rock thermal property measurements, and give a brief description of some of the simulated results obtained for a mechanised cut and fill stope case study from the Homestake Gold Hine in South Dakota.

Jan 1, 1985

By J. F. Barkley

[There is a general concept in the, coal trade that the moisture- and ash-free B.t.u. of coal from the same seam, and. surely from the same mine, is substantially a constant; that calculation of the -moisture- and ash-free B.t.u. value from the proximate analysis and B.t.u. determined in the laboratory will reveal whether a coal came from a given area or sears; and that, having this constant, the B.t.u. value of a coal sample can be calculated fairly closely upon a dry or as-received basis from the moisture and ash values of its proximate analysis.]

Jan 1, 1941

By Daniel Antonio Kapper Fabricio

O módulo de tenacidade é um parâmetro que representa a energia absorvida por um material até a ruptura, e é uma variável importante para avaliar se o material sofrerá fratura quando em serviço. A tenacidade é determinada através da área sob a curva tensão-deformação de engenharia, a qual é difícil de ser calculada analiticamente. Assim, o presente trabalho propõe a utilização de métodos numéricos para o cálculo do módulo de tenacidade através de planilhas eletrônicas. Como resultados são apresentados o procedimento desenvolvido e os valores obtidos na estimativa da tenacidade de uma amostra, assim como a comparação do resultado com o valor calculado analiticamente e com o valor calculado através de um método simplificado. Conclui-se que o valor numérico calculado é tão próximo do verdadeiro quanto maior o número de pontos obtidos na curva tensão-deformação de engenharia, viabilizando a utilização desse método na estimativa da tenacidade de uma ampla gama de materiais. Além disso, o método numérico pode ser usado na determinação de outras propriedades calculadas através da área sob curvas.

Aug 7, 2018

By A. M. Kiwior

In 1969, the Congress of the United States declared that "the first priority and concern of all in the mining industry must be the health and safety of its most precious resource - the miner," Therefore, Public Law 91-173, Federal Coal Mine Health and Safety Act of 1969, was enacted. Since haulage accidents account for a high percentage of coal mining accidents, Section 314e, ?Hoisting and Mantrips,? was included in the law. This section states: "Each locomotive and haulage car used in an underground coal mine shall be equipped with automatic brakes, when space permits. Where space does not permit automatic brakes, locomotive and haulage cars shall be subject to speed reduction gear, or similar devices approved by the Secretary which are designed to stop the locomotive and haulage cars with the proper margin of safety."

Jan 1, 1975

By R. Hogg, J. M. Mutmansky, E. Kaya

"Characterization of the size, shape, chemical composition, and mineralogical content of mine airborne dusts generally requires a larger mass of dust particles than is typically collected using traditional sampling devices. In this paper, the general design of a passive dust collector is described and the field results are presented. The collector was constructed of galvanized sheet metal duct with a resin-coated honeycomb to provide an elutriation-type system for particle collection. Several versions of the collector were used in the field portions of the research.The dust samples collected from underground coal mines were found to possess angular particle shapes, relatively consistent size distributions, and elemental compositions that showed relatively little variation, at least for the more prevalent elements. In addition, the distributions of particles sizes obtained from the passive dust collector appear to be similar to those of samples collected at the same time in a conventional personal sampler except that the passive device seems to collect a larger quantity of coarse, nonrespirable particles. Conclusions on the suitability of this dust collector for collecting characterization samples are presented. In addition, the potential for using such a dust collection system for supplying dusts for biomedical research is discussed.INTRODUCTIONRecently, a considerable amount of research effort has been directed toward better understanding of the characteristics of the coal dust generated during the mining process. It is generally believed that dust characteristics play a significant role in the development of Coal Workers' Pneumoconiosis (CWP). In order to effectively protect coal workers from coal dust, it is important to understand the properties of dust, the mechanisms of generation and dust-lung reaction. Conducting research on dust characterization, dust control and the biomedical aspects of dust toxicology generally requires a large sample of airborne coal dust. Unfortunately, current dust sampling instruments are not able to meet this demand because only a few milligrams of dust are collected."

Nov 1, 1995

By K. Boakye

This paper presents the results of a review of historic blast design practices at the Dragon Products Company, LLC (Dragon) Quarry Operation, along with the results of two different blast design vibration monitoring programs. A blast pattern design modification was initiated to determine if production volume per shot could be increased and highwall instability could be decreased. A vibration monitoring program was undertaken to investigate peak particle velocity (PPV) and relate the data to the blastability of the jointed onsite rock mass, utilizing the relationship between PPV and dynamic stress and strain. The Dragon Quarry Operation has historically used a 6-in. diameter, 14-ft by 14-ft production blast pattern, with blast holes loaded manually using cartridge style explosive products. In 2011, Quarry Operations introduced a 6-in diameter, 16-ft by 16-ft production blasting pattern, using pre-mixed, truck-loaded, bulk emulsion/ammonium nitrate/fuel oil (ANFO) blends. This paper summarizes the results of the blast design modifications, the results of the vibration monitoring data, and describes how production blasting and excavation at the Dragon Quarry has benefited from such modifications.

Feb 27, 2013

By R. Q. Honaker, D. P. Patil, A. Sirkeci

Due to increased production of fine coal during mining during this century and inefficient fine coal recovery technologies, a vast reserve of high quality coal currently exists in refuse ponds. A novel fine coal circuit consisting of a hindered-bed classifier, an enhanced gravity concentrator and a flotation column has been evaluated for the recovery of fine coal from refuse ponds. The treatment of a pond derived from Pittsburgh No. 8 seam coal resulted in the production of a premium fuel containing less than 5% ash and a calorific value of about 30,173kJ/kg with 60% mass yield. The results from the treatment of two refuse pond materials will be presented in this publication.

Jan 1, 2000

This volume contains a series of papers describing research conducted by the Bureau of Mines to develop or improve equipment and systems that satisfy the communication requirements of miners doing work related to rail, belt-conveyor, trackless, and hoist haulage systems.

Jan 1, 1977

By Mariana Beatriz dos Reis Silva

A influência do tempo entre passes na evolução microestrutural de dois aços austeníticos, F138 (sem nióbio) e ISO 5832-9 (com nióbio), foi investigada através ensaios de torção a quente em condições industriais. Análises foram realizadas através de microscopia ótica e eletrônica de transmissão, EBSD e microdureza. Menores tempos entre passes produziram menores tamanhos de grãos e de precipitados. Microestruturas mais refinadas induziram a maiores microdurezas. O aço ISO 5832-9 apresentou maior resistência que o F138. Precipitações de TiNbN, após o encharque, e de NbCrN e NbN (5%), durante o processamento, foram observadas no aço ISO 5832-9. Ambos os materiais sofrem recristalização dinâmica, partículas grosseiras (> 200 nm) atuaram como partículas de reforço e partículas menores (< 50 nm) no ancoramento dos contornos de grãos e discordâncias no ISO.

Jan 16, 2018

By D. Bois, P. Keating, J. Lemieux, M. A. Vallée, M. Allard, R. S. Smith, L. Z. Cheng, M. Chouteau, K. Fountain

"A comparison of data from INPUT, GEOTEM, and MEGATEM airborne electromagnetic (AEM) systems over the Aldermac deposit, Québec, Canada, was undertaken to evaluate the relative ef¬ficiency of these systems for the detection of small, deep conductors. The Aldermac orebody was mined between 1933 and 1934 to a depth of 200 m. A deeper mineralized zone was discovered in 1987. The MEGATEMII system was used to acquire 90- and 30-Hz data over the deposit in 2003 as part of a research project. These MEGATEMII data were compared with data acquired by other AEM systems (GEOTEM and INPUT), and the results show that the MEGATEMII response is ten times larger than the other sys¬tems. For the dB/dt response, 30 Hz gives a better signal-to-noise ratio, whereas 90 Hz has a better signal-to-noise ratio on the B-field.The data were evaluated by numerical modeling. The deposit was best represented by a complex mod¬el, comprising two weakly conductive bodies to approximate the alteration halo, two deeper prisms repre¬senting known orebodies, and three bodies ranging in thickness from 3 to 6 m and in resistivity from 12 to 20 ohm·m, representing the chargeable overburden. This implies that the MEGATEMII system is able to see a small conductive body at more than 200 m depth in an area where the response is contaminated by conductive overburden."

Jan 1, 2009

By K. G. Tshilombo

It should be possible to use an oxygen probe to follow iron removal during converting, if local equilibrium is established between iron in the matte and the iron oxides in the fayalitic slag. The oxygen activity is expected to increase strongly as the iron content of the matte decreases (and the iron activity in the matte drops) while the iron oxide activity in the slag remains constant. To test this idea, oxygen activities were measured in synthetic mattes (made up of mixtures of Cu2S, FeS and Ni3S2) when in contact with silica saturated SiO2-FeO slags, and silica and (initially) magnetite saturated SiO2-FeO-Fe3O4slags. The measurements were performed on laboratory scale at 1250°C, using an oxygen probe consisting of an MgO-stabilized zirconia electrolyte and Fe/FeO reference, and containing the sample in a silica crucible. Electrical contact to the matte was by means of a platinum wire. The measured oxygen activity was sensitive to the iron content of the matte, and insensitive to the composition of the gas atmosphere over the melt. The measured oxygen activity was generally close to that predicted by Fact Sage calculations. This indicates that such oxygen activity measurements could be useful to monitor iron removal during converting of nickel-copper-iron mattes.

Jan 1, 2007

By Michael Wieland

The resolving capacity of the thermodynamic work-principal model has been seriously refined over its twelve year history, so a review of the innovations, wrong turns and their rectification is warranted to help future researchers. The work-principal model rests upon the four laws of thermodynamics that drive the universe and relatively few other assumptions: like the removing and imposing of constraints on the quasi-potential to yield trapped minimum key-states that represent the wanted process. The formative research was concerned with the role of ingredient changes, the removal of booster influence and the quench temperature with which to reckon toxic fumes. The transfer of reaction-zone energy as work upon the surrounding rock/water/fixture was not fully rationalized until the notion of reversed-inertial pressure was formulated and determined (for water) with underwater trinitrotoluene (TNT) shots. The rock-water-jelly model incorporated that term into its dynamic pressure formula as a way to represent rock blasts or underwater shots, while the zone of reaction gases remained trapped. The real irreversible thermodynamic process, which yielded the total expansion work, was later complemented with a wholly reversible imaginary process, to form a closed thermodynamic loop, with a remarkable consequence – the determination of the theoretical heave and hence, the undissipated-shock by difference from the total work. With the wholly developed model, it was recently possible to quantify the time retardation of reaction chemistry for non-molecular (mining) explosives, as compared to the rather negligible time-retardation found for the molecular (military) explosives in underwater tests.

Jan 1, 2009