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By S. Eck

In previous work the influence of the casting speed on the flow field and the shape of the solidification front in an industrial 0.82 x 0.25 x 0.8 m³ bronze caster had been investigated. Both numerical and experimental model represented 1:1 the real caster geometry. A comparison of the results of both numerical and experimental models for the flow during the casting process showed a good agreement in the qualitative velocity fields (flow direction and vortex formation). This work represents a parameter study of the numerical model with variations of the turbulence conditions at the inlet in order to clarify their influence on the flow field in the caster. In order to find the best boundary condition at the inlet, the numerical calculations for water have been compared with the measured flow fields in the water model. The new boundary conditions were then applied to the numerical model of the bronze casting process.

Jan 1, 2009

By R. J. Gunderman

A conventional trailing cable connection box on a continuous mining machine was modified by the addition of two innovative devices. These are a pressure vent to preclude buildup of high pressure due to an explosion in-side the enclosure, and a grommet-type cable entry to simplify and speedup cable entering procedures. The innovative devices were evaluated for eight and one-half months in a working section of an underground coal mine. Laboratory tests before and after the in-mine exposure show no measurable change in the devices. Following the favorable in-mine evaluation, technical performance criteria were defined to serve as the basis of approval for the use of the innovative devices. Additional tests to measure comparable gripping of the cable by asbestos rope, substitution rope materials and by the urethane grommet-type entry were included in this effort. Also, literature for the last 80 years was searched. Comments are provided as to how the innovative devices comply with 30 CFR Part 18.

Jan 1, 1982

By Maral Malekian, Pat Bellett, Eranda Tennakoon, Fernanda Carrea, Moe Momayez

Slope instabilities in open-pit mines pose a safety risk to workers and a financial burden on production. The direct impact of slope stability on safety and production makes slope failure predictions one of the important challenges in the mining industry. Predicting the precise time of slope failure has been the subject of much research in conjunction with the development of innovative monitoring technology designed to prevent sudden failures. This paper investigates the use of AutoRegressive Integrated Moving Average (ARIMA) model to predict the time of slope failure. Input data such as inverse velocity (IV) and dimensionless inverse velocity (DIV) from 20 slope failures were used to train the model predict the failure time. For comparison purposes, the time of slope failure using the traditional inverse velocity method is also provided. We show that ARIMA provides 90% more accurate predictions than the TIV approach.

Jul 12, 2023

By Willy Ank de Morais

O estaqueamento profundo é necessário para obter fundações firmes e confiáveis, mesmo em solos de baixa resistência. Após completar a soldagem entre dois perfis, através do uso de talas, que compõe uma estaca de uma fundação profunda, essa união é inserida, juntamente com o restante da viga, através de uma máquina de estaqueamento. Neste processo a região da emenda pode sofrer choque térmico devido à umidade presente no solo. Este trabalho visa demonstrar a viabilidade da imediata inserção (‘cravação’) no solo de juntas entre perfis de aço ASTM A572 Grau 50, efetuadas através da operação de soldagem com eletrodo revestido (E 7018), simulada através de uma condição de maior criticidade pelo processo de arame tubular.

Oct 30, 2017

By Gary Choate

The work presented in this report represents the background activity which led to the fabrication and testing of a greenhorn and crowd limit switch system for electric shovels. The program began With a literature search and manufacturers product review to gather material as a basis for concept generation. Visits to three open pit mines provided information from operation and maintenance managers which was useful in preparing design concepts. These concepts were evaluated through laboratory tests and engineering analysis to select a final design concept. The resultant greenhorn is four separate shock absorbing pads each enclosed in a housing which bolts to the end of a dipper handle adaptor. The plungers impact against stops mounted to the saddle block. The crowd limit control is a nonmechanical device which senses the location of the dipper and makes appropriate commands to the crowd motor to insure against impacting the greenhorns. The electronic crowd limit control is redundant and indicates malfunction modes. The greenhorn prevents shovel damage in the unlikely event of impact.

Jan 1, 1983

By E. Pizarro, A. Videla, G. Compan

One of the main problems related to mining investment decisions is the use of accurate prediction models. Metallurgical recovery is a major source of variability, and in this regard, the Chuquicamata processing plant recovery was modelled as a function of geomining-metallurgical data and ore characteristics obtained from a historical database. In particular, the dataset gathered contains information related to feed grades, ore hardness, particle size, mineralogy, pH, and flotation reagents. A systemic approach was applied to fit a multivariate regression model representing the copper recovery in the plant. The systemic approach consists of an initial projection of the characteristic grinding product size (P80), based upon energy consumption at the particle size reduction step, followed by a flotation recovery model. The model allows for an improvement in the investment decision process by predicting performance and risk. The final geometallurgical model uses eight operational variables and is a significant improvement over conventional prediction models. A validation was performed using a recent data-set, and this showed a high correlation coefficient with a low mean absolute error, which reveals that the geometallurgical model is able to predict, with acceptable accuracy, the actual copper recovery in the plant.

Jan 1, 2015

By Gustavo Henrique Bolognesi Donato

Ensaios de curva R (J vs. ?a – crescimento dúctil de defeitos) e de propagação de trincas por fadiga (da/dN vs. ?K) são balizados por normas como a ASTM E1820, ISO 12135 e E647, as quais exigem dimensões mínimas para as amostras C(T) ou SE(B) a fim de garantir condições SSY e portanto a validade de K e J. Entretanto, tais exigências usualmente conduzem a dimensões expressivas que dificultam a retirada de amostras de chapas finas ou mesmo de muitas estruturas reais. Como alternativa, estudos de Koppenhoefer e Dodds (1998) e mais recentemente de Shin e Lin (2012) indicaram a possibilidade de uso de amostras em miniatura (inclusive Charpy contendo pré-trinca) para determinação de curvas R e da/dN vs. ?K. As grandes questões são a viabilidade de ensaio de amostras pequenas com repetibilidade e a adequada avaliação dos limites de validade das forças motrizes nestas geometrias, a fim de garantir condições de similitude. Como um passo nesta direção, este trabalho investiga o potencial de amostras Charpy pré-trincadas (10x10x70mm) na determinação de curvas R e da/dN vs. ?K. Inicialmente, ensaios de ambos os tipos foram realizados em amostras de um aço estrutural ferrítico empregando uma máquina universal MTS 810. Apesar das dimensões reduzidas dos espécimes, os ensaios se mostraram viáveis e apresentaram boa repetibilidade e estabilidade dos resultados experimentais. Ainda, boas práticas de ensaio puderam ser estabelecidas para suportar os trabalhos futuros com tais geometrias.

Aug 8, 2018

By Robin B. Dill, Mark Pelletier, Daniel J. Dobbels, Subodh Bhaumik, Daniel J. VanRoosendaal

Although primarily cut-and-cover excavations are required for replacement of the existing elevated I-93 interstate highway through the heart of Boston for the Central Artery/Tunnel (CA/T) project, some mined tunnel construction was also undertaken. The mined tunneling conducted was the 22-m-wide northbound roadway structure which passed below a 20-m-deep operating underground subway station that was built in 1913. The innovative underpinning scheme used to support the subway station during construction resulted in the successful mining beneath the subway station with negligible vertical settlement. Two grouting galleries were carefully mined below the subway structure, and pre-grouting of the granulary, pervious glacial soils and weathered bedrock was carried out from these galleries. The reinforced concrete walls of the underpinning structure were constructed within three stacked drifts that were sequentially mined below each grouting gallery. After 11 cross adits were mined between the grouting galleries, cast-in-place post-tensioned girders that spanned between the stacked-drift walls were constructed to support the subway station. The stacked-drift walls also provided lateral support for the 22-m wide by 29-m long by13-m high opening beneath the girders.

Jan 1, 2001

By Sanford J. Douglas

This publication describes a study by the Federal Bureau of Mines of devices and methods used for testing and splicing 4,160-volt and 440-volt cables and for providing ground-fault protection for 440-volt circuits, as developed and used by the electrical staff of the Tecumseh coal mine, an open-pit operation at Boonville, Ind. The testing and ground-fault devices described should find ready application in other open-pit mines, and, with suitable modifications for voltages involved, in underground mining. The devices and testing methods are based on sound engineering principles and are time-tested and economically feasible, Four devices are used: A high-voltage tester, and a low-voltage high- current tester, both for testing 4,160-volt cables; a tester for 440-volt cables; and, electronic ground-fault protective device for 440-volt cable circuits. All the cable testers and the grounding device were designed and built at the mine from standard parts. They are inexpensive, dependable, and job tested, An attempt has been made here to describe them in enough detail so that interested persons can assemble duplicate units.

Jan 1, 1960

By C Nyoni, T Nguyen, C R. W Seymour, G D. Dempers

Unplanned dilution directly adds cost to production from mining, milling, tailings disposal and administration. Additionally, unplanned dilution decreases the productivity, profitability and may affect the planned life of mine. Identifying and quantifying the potential for unplanned dilution allows optimisation of the mining plan and mining practices to minimise the adverse impact on productivity and the cost of production. The Dilution Rating System (DRS) has been developed to more accurately predict dilution thickness and the variable potential for dilution, from individual stopes to life of mine planning. The DRS utilises the methodology developed for the Mining Rock Mass Model (Seymour et al 2007, Jenkins et al 2009) to generate a three-dimensional dilution rating model, which is then calibrated against stoping performance. Dilution can be predicted more accurately and the parameters affecting dilution can be determined and minimised through improved mining techniques, for example blasting and ground support design. Potential high dilution areas can be identified in the planning stages of the mine and systems put in place to mitigate the risk of excessive dilution. This paper presents the methodology used to develop the DRS and then successfully predict dilution for both the hangingwall and footwall of stopes at the Gara Gold Mine. This has enabled the expected dilution to be more accurately predicted and mitigated where possible thus reducing unplanned dilution.

Mar 15, 2021

By John C. Machisak

THIS PUBLICATION presents injury experience and employment data for the nonmetal mining industry in the United States for 1960. Data for the mines and mills are presented separately, as shown in the list of tables. The Bureau of Mines is authorized to send questionnaires to the nonmetal mining industry for their voluntary submission of injury and employment data. As the information submitted contributes largely to the promotion of safety in the industry, special effort has been made to ma e these questionnaires as complete as possible.

Jan 1, 1963

Talvivaara deposits, Kuusilampi and Kolmisoppi, comprise one of the largest sulfide nickel resources in the world with 642 Mt in Measured and Indicated Resource categories. TalvivaaraÆs preferred extraction technology is bioheapleaching, which is already widely used for other metals, notably copper and gold. The company has demonstrated the viability of bioheapleaching technology for the extraction of nickel using the Talvivaara ore. The leaching process is heat generating and therefore suitable for the subarctic climatic conditions. The planned annual metal production is 33 000 t of nickel, 60 000 t of zinc, 10 000 t of copper and 1200 t of cobalt. Talvivaara deposits are well-suited for open pit mining due to a thin overburden, favourable resource geometry and a low waste to ore ratio. The ore is relatively low-grade, but well suited to bioheapleaching due to its high sulfide content. Bioheapleaching is a process whereby metals are leached from ore as a result of bacterial action. The bacteria used in the Talvivaara bioheapleaching process are endemic to the area and therefore well adjusted to the prevailing environmental conditions. The solution is collected at the bottom of the heaps and either re-circulated through the heap or fed to metal recovery. In metal recovery, nickel, copper, zinc and cobalt are precipitated from the pregnant leach solution and filtered to produce saleable metal products. After the metals are removed, the solution is further purified and returned to irrigate the heaps. Mining, bioheapleaching and metal recovery techniques for the Talvivaara mine have been tested in a 17 000 t on-site demonstration trial during 2005 and 2006. Subsequent construction of the mine started in 2007 and commercial production in the fourth quarter of 2008.

Jan 1, 2009

Many states rely upon the Pennsylvania 1957 “Gas Well Pillar Study” to evaluate the coal barrier surrounding gas wells (Commonwealth of Pennsylvania, 1957). The study included 77 gas well failure cases that occurred in the Pittsburgh and Freeport coal seams over a 25-year span. At the time, coal was mined using the room-and-pillar mining method with full or partial pillar recovery, and square or rectangle pillars surrounding the gas wells were left to protect the wells. The study provided guidelines for pillar sizes under different overburden depths up to 700 ft. The 1957 study has also been used to determine gas well pillar sizes in longwall mines since longwall mining began in the 1970s. The original study was developed for room-and-pillar mining and could be applied to gas wells in longwall chain pillars under shallow cover. However, under deep cover, severe deformations in gas wells have occurred in longwall chain pillars. Presently, with a better understanding of coal pillar mechanics, new insight into subsidence movements induced by retreat mining, and advances in numerical modeling, it has become both critically important and feasible to evaluate the adequacy of the 1957 study for longwall gas well pillars. In this paper, the data from the 1957 study is analyzed from a new perspective by considering various factors, including overburden depth, failure location, failure time, pillar safety factor (SF), and floor pressure. The pillar SF and floor pressure are calculated by considering abutment pressure induced by full pillar recovery. A statistical analysis is performed to find correlations between various factors and helps identify the most significant factors for the stability of gas wells influenced by retreat mining. Through analyzing the data from the 1957 study, the guidelines for gas well pillars in the 1957 study are evaluated for their adequacy for room-and-pillar mining and their applicability to longwall mining. Numerical modeling is used to model the stability of gas wells by quantifying the mining-induced stresses in gas well casings. Results of this study indicate that the guidelines in the 1957 study may be appropriate for pillars protecting conventional gas wells in both room-and-pillar mining and longwall mining under overburden depths up to 700 ft but may not be sufficient for protective pillars under deep cover. The current evaluation of the 1957 study provides not only insights about potential gas well failures caused by retreat mining but also implications for what critical considerations should be considered to protect gas wells in longwall mining.

Jul 28, 2020

Investigation on Comprehensive Utilisation of Nickel Slag from JNMC

Sep 13, 2010

By D. W. R. Haysom

"I AM CONSCIOUS of the honour you pay me by having invited me to address you on the subject of the Rehabilitation of the Sydney Steel Corporation. The true architect of the revival and rehabilitation is Robert Burns Cameron. Because of the numerous myths which have grown up around what seems to be the miracle of the revival of the Sydney Steelworks, I propose to go back to the time when they came under the full control of the Province, on the 1st of January, 1968. Late in 1967, the decision was taken by Premier G. I. Smith to keep the Steel Plant running for at least another year, in an endeavour to see whether the enormous losses being sustained by Dosco could be reduced to a level which would permit their continuing operation. When that decision was taken, Dosco was to continue management until the 30th of April, 1968, and in the intervening period, the Provincial Government would seek management of the right calibre to ensure that an objective view of the Steelworks operations could be secured. By a combination of circumstances which can only be described as most felicitous, the man selected for the task was R. B. Cameron. He very quickly determined that to permit Dosco to continue management of the Steelworks until April 30 could only result in heavy losses to the Province and a consequent deterioration in the already critical financial position and a declining morale of the worke"

Jan 1, 1972

By Charles Pol Vuillier

Piling work for modification to the Charles Grimes Bridge in Melbourne, Australia required piles to be installed through 15 to 20 m thickness of very soft to soft silty clay overlying 10 m of stiff clays and sands in turn overlying siltstone. The presence of an old sewer founded at depth in the soft clays demanded that vibrations be kept to a minimum. Two pile type were used by Vibro-pile (Australia) to provide the client with the most economical piling price. The two pile types were CFA piles of 750mm diameter founded in the weathered rock and a full displacement concrete injected screw pile developed by Vibro-pile called the "Z" pile, founded on the rock. The development and features of the "Z" pile are briefly discussed, including the perceived applications and advantages of the pile type. On board instrumentation comprising a computer was used to monitor all aspects of the construction. The rig instrumentation provided an important quality control measure that gave confidence in the pile installed. Pile performance was proved on the cast in situ piles by dynamic load testing methods. Initially tests performed with a 120 kN drop hammer, which was not capable of mobilising the required loads. The performance was then satisfactorily proved by using a drop hammer of 20 tonne mass delivering blows drop heights of 1.5m. Low strain integrity tests on a number of piles were also used to confirm the structural integrity of the piles.

Jan 1, 2000

By Bright Oppong Afum, Kojo Boakye, Kwaku Boakye

This research developed and simulated a novel multi-indicator Fatigue Detection and Alert System (FDAS) designed to enhance fatigue detection accuracy in mining environments. The system integrates a comprehensive set of inputs: eye blink rate, eye closure duration, yawning frequency, distraction levels, Pre-shift Check-in Scores (Self-report) and Electroencephalography (EEG) Levels. Using MATLAB’s Fuzzy Logic Rule Viewer (FLRV) and Simulink, simulations demonstrated the FDAS’s robust ability to process these diverse physiological and behavioural indicators accurately. It effectively classified operator fatigue into low, moderate, and high fatigue levels, consistently providing appropriate outputs and corresponding intervention recommendations across various mixed-signal scenarios. The system achieved a calculated accuracy of 85.19% across 27 test entries, with a standard deviation of approximately 1.8459, confirming its reliability for real-time fatigue monitoring. These findings highlight the significant potential of this fuzzy logicbased approach to proactively identify early signs of fatigue, substantially enhancing safety and operational efficiency in demanding mining operations.

Feb 22, 2026

By B Johansson

The mining industry needs to recruit young talented people. An important task therefore, is to create future attractive mining workplaces that engage and motivate young people to work within the industry. Our intention with this article is to illustrate a possible way forward for the mining industry to form such workplaces. We discuss different aspects of an attractive workplace and summarise our findings in a specification of basic demands dealing with safety, physical and psycho-social work environments and social responsibilities.

Nov 22, 2011

By D S. Clarke, K B. Sporli

The Thames Goldfi.eld has been a major gold resource in the west of the Coromandel Peninsula, New Zealand, with the Waiotahi quartz vein system forming a large part of the field. Mineralisation is hosted by hydrothermally altered Miocene andesitic volcanic rocks. Both massive columnar-jointed and fragmental volcanic rocks are present. The vein system is dominated by the steeply dipping NE striking Waiotahi-Cambria vein, and associated splays. Hydrothermal alteration increases in intensity from isolated blocks of propylitic altered andesitic material, into the intensely clay altered equivalent. Low rank propylitic alteration is typified by chlorite, calcite and pyrite, with local illite or epidote. Clay alteration is characterised by illite, quartz, kaolinite and pyrite. While broadly forming halos around veining, intense clay alteration also occurs in strongly jointed portions of the hostrock.   Vein textures and the intense illitic clay alteration at Thames are similar to those in some of the other epithermal gold deposits of the Coromandel Volcanic zone, and in deposits of the Philippines, all related to andesitic terranes. Possible causes for textures and alteration being different in these deposits from the more classic Quartz-Adularia-Illite type epithermal systems may be that cooling/mixing rather than boiling dominates fluid evolution. Kaolinite may be also be a product of either of these different fluid types, or has resulted from overprinting of an illitic assemblage by downward percolation of acidic fluid.

Jan 1, 1991

By M. Jaffe

The data developed in this study establishes the technical and economic feasibility as well as the improved health and safety characteristics of a novel mining concept. The mining concept is a modified longwall technique using prestressed tendons for roof control, longhole blasting for fragmentation, and remote mucking. The technical feasibility was found to be dependent on the state of the art, while economic feasibility was found to be dependent on particular minerals and on supply and demand. Since these two conditions are not necessarily coincident in time the data is presented in the report in a manner that enables the mining engineer to perform a rapid preliminary technical and economic analyses for a specific property.

Jan 1, 1977