Search Documents

By Gary E. Sherman

To aid the U.S. Army Corps of Engineers in their Resource Development Navigation Study, the U.S. Bureau of Mines (Bureau) examined the potential for mineral development near ten Alaska port sites. This report presents the results for the following four sites: Balboa Bay, Beluga, Lost River, and Point MacKenzie. There are 579 known deposits within the area considered for these ports. The majority of the deposits are located within a highway/railroad corridor examined for the Point MacKenzie port site. Based on the current level of knowledge, coal deposits near the Beluga and Point MacKenzie port sites are most likely to be developed in the near future. This conclusion is based on the fact that coal projects in these areas are actively being pursued for development. The mineral wealth surrounding the four port sites is substantial. Mine models were used to examine the potential for mining tin, gold, silver, copper, and molybdenum. The models were based on published reserve and grade data and therefore do not include proprietary company data which, if available, would likely change the analysis results. Of the models examined, the tin placer mine model developed for the Lost River port site proved to be closest to being economic.

Jan 1, 2011

By E Rubio

El imaginario común sobre la construcción de la minería a cielo abierto es que requiere de equipos pesados para obtener mayores producciones. Sin embargo, la aplicación de este método en los minados de vetas de plata en las minas de Julcani de la Compañía de Minas Buenaventura, resultó de gran aporte. En ese sentido, el presente trabajo describe el proceso técnico de este método de explotación en esta producción de plata, asi como señala los beneficios económicos para la pequeña y mediana minería.

Nov 20, 1972

By Jonathan Baggett, Nino Ripepi, Amin Abbasi, Richard Bishop, Juan Monsalve, John Hole

This work focuses on the operational and safety issues associated with karst voids in large opening underground mines. Issues include water inrush, structural instability, and engineering uncertainty in these environments. Coupled with the fracturing prevalent in folded sedimentary rocks, karst voids are complex and challenging ground-control risks. Traditional methods of predicting karst void locations, such as probe drilling, are impeded by the inconsistent spatial distribution and variable sizes of the features as reported by Li et al. (J Rock Mechan Geotech Eng:232–242, 2010) and Hassan et al. (Procedia Chem 19:737–742, 2016). Ground-penetrating radar (GPR) is a geophysical technique that transmits radio waves into a medium and subsequently detects reflected waves via a receiver. The travel time and energy of received signals are then processed and interpreted. The difference in conductivity and dielectric permittivity between limestone and open karst cavities causes strong reflections. GPR is frequently used as a geophysical surveying technique in several industries; however, there is a lack of published research on underground mining GPR applications as reported by Zhao et al. (2015a; Geophys J Int:62–71, 2015b) and Eskelinen and Pellinen (Constr Build Mater:888–898, 2018). The purpose of this work is to demonstrate the use of GPR in an underground stone mine and to discuss the importance of karst void detection ahead of mining.

Underground mine designs typically try to avoid extraction beneath streams and rivers of any significant size, especially when the overburden rock thickness between the stream bed and the mine is thin. Potential issues with mining beneath streams include excessive groundwater inflow to the mine; weak ground (roof, floor, and pillar) conditions; horizontal stress effects; as well as stream loss and other potential adverse environmental effects. However, there are times when crossing beneath a stream or river is necessary to move into a new area of mineral reserve without creating additional mine access points from the ground surface. Often, stream crossings are completed without thorough assessment, potentially resulting in increased costs, decreased safety, and, in some cases, failure to advance the mine. Selection of the most favorable location(s) to cross the stream must account for numerous factors and the associated assessment often requires a multidisciplinary approach. Stream crossing investigations often require geological, hydrogeological, geotechnical, and geophysical expertise. Phases of stream crossing investigations include desktop evaluation of maps and aerial photography, stream bed observations, drilling, detailed rock core logging, downhole geophysical surveying, hydraulic conductivity testing (packer testing), geotechnical laboratory testing, assessment, and reporting. The deliverables from a stream crossing assessment typically include geological, geotechnical, and hydrogeological characterization of potential stream crossing locations; classification of favorable and unfavorable crossing locations; recommendations for entry design and pillar sizing; and recommendations for if, and how, to conduct pre-grouting activities. Examples of technical aspects of data collection and assessment are provided based on decades of industry experience conducting stream crossing assessments in various underground mining scenarios.

Jul 28, 2020

By Chris Bennett, Drupad Desai, Kirit Mevawala

INTRODUCTION The design/build (D/B) philosophy of contract delivery is neither new nor unusual when it comes to at-grade, elevated or high-rise structures. But when it comes to constructing underground facilities, there were no examples to be followed in early 90sin the continental United States or its territories. When DMJM+HARRIS was selected as general architectural and engineering consultant for the Tren Urbano (TU) project in Puerto Rico, one of the requirements of the Federal Transit Administration (FTA) for funding commitment was to use TU as a demonstration project utilizing design/build contract delivery method. Now fifteen years later, New York City Transit (NYCT) has instituted a similar requirement for their first Tunnel Boring Machine (TBM) contract for the Second Avenue Subway. As with most construction mega-projects, lots of things have happened and there were several lessons learned from the TU experience that are now being applied to Second Avenue. Both of these projects require building tunnels and underground transit facilities in heavily traveled corridors of an urban city, in the vicinity of active business and commercial enterprises. To enhance the challenge, there are noise and vibration sensitive and historic urban receptors either over or along both the transit corridors. Column free Tren Urbano station caverns over18 m (60 ft.) wide were built in soft ground conditions within 3.6 m (12 ft.) of the surface under an aging heavy utility corridor, while NYCT tunnels with station structures stretching the limits of rock caverns to 34.8 m (100 ft.), were planned in rocky geology with the presence of shear and fault zones and some mixed face conditions. BACKGROUND During the early period of design/build experimentation, the speed with which the contract procurement packages could be put together enabled the owners to take advantage of the major efforts underway to rebuild the infrastructure that was suffering from post-World War II neglect. Use of design/build for new starts was unheard of and most of the projects were smaller in nature in order to allow the methodology to be tested. Development of functional design packages with the understanding that the D/B

Jan 1, 2005

By J. B. Fletcher

The Miami mine first started operations in 1910. For convenience, the history of the orebody can be divided into the following categories (Fig. 1): 1) 1910 to 1925: 24.4 million tons of high grade ore, mined by top slicing, sublevel caving, etc. 2) 1926 to 1954: 102 million tons of low grade ore, mined by block caving.

Jan 1, 1961

By K. D. Hester

"1.0 INTRODUCTIONThe uranium industry started in Canada with the reopening of the gravity concentrator at Eldorado's Port Radium mine in the North West Territories in 1942. In 1948, uranium exploration and processing was opened to the private sector, and the Federal government offered special pricing incentives to the industry. Eldorado explored the Lake Athabaska deposits in northern Saskatchewan, and in 1953 opened the Beaverlodge mine. Other mines in the area soon followed. In 1953 also, the deposits in the Blind River - Elliot Lake area and in the Bancroft area of Ontario were discovered. Mines and mills were quickly developed in these areas.Canadian uranium production peaked at 15,900 short tons of U3O8 in 1959. In that year, uranium exports at $300,000,000 exceeded those of all other minerals in value. On October 1, 1959, Canadian uranium operations employed 13,900 people.Up to 1956, it was a seller's market. By 1958, world production of uranium was far ahead of requirements. Accordingly, in November of 1959, the USAEC announced it would not renew it's options for continued delivery of uranium from Canadian mines. This led to the ""stretchout"" of existing uranium contracts, and many mines were shut down (see Table 1) .In the early 1970's, a commercial uranium market seemed to be developing. In Ontario, at Elliot Lake and Bancroft, mines reopened. But competition was coming from the Athabaska basin of Saskatchewan. Currently it is these high grade, open pit deposits of northern Saskatchewan which are in the forefront of Canadian uranium developments. Canadian developments since 1942 reflect the political and market forces, as well as metallurgical progress and changes in environmental standards. This paper attempts to show these process changes in broad perspective."

Jan 1, 1987

By I Thin, L Morizzi, C Seymour, G Mungur

Olympic Dam has been investigating mine design options for the South Mine Area (SMA), which will continue using the existing sublevel open stoping (SLOS) method. The SMA is an undeveloped mining area, located south of the existing underground mining areas currently in production at Olympic Dam. The SMA study reached the stage where geotechnical inputs were required for stope design, infrastructure location and ground support forecasts. A large database of geotechnical data was collected to inform open pit designs for the ODX (Olympic Dam expansion) project (resulting from 659 drill holes). This geotechnical data has since been reprocessed to align with design inputs required for the SLOS mining method. The result has been the construction of a preliminary three-dimensional mining rock mass model (MRMM) that has been incorporated into preliminary stope mine design and infrastructure layout assessments, which have taken into account the predicted prevailing ground conditions.As with any model, it is necessary to improve the confidence in its predictability; therefore the model must be calibrated. The preliminary SMA MRMM was no exception. First pass calibration was possible with results from underground geotechnical window mapping from exposed rock mass conditions in the lateral development and surface geotechnical holes for ventilation shafts.The SMA project continues to advance and has started a program of resource drilling. Selected holes have been identified that target data limited areas. This will ensure that the data gaps are infilled in order to maintain the required data density required to improve the model confidence. In addition, further underground window mapping in the SMA will provide ‘mine scale drill hole’ data that can be used to either update the MRMM or as part of planned future calibration. Stope performance data from stopes will provide further valuable data for calibration purposes.The proposed paper will present the process and findings that have been followed in order to establish a well calibrated geotechnical model that can be used with an acceptable level of confidence in the ongoing refinements of the mine design and planning process for the SMA.CITATION:Thin, I, Morizzi, L, Mungur, G and Seymour, C, 2016. Building and calibration of a geotechnical model for sublevel open stope design at Olympic Dam, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 523–532 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By R. D. Pehlke, J. V. Gluck

AS a portion of a general study of liquid-metal thermodynamics, high-temperature galvanic cells were used to study the effect of added dilute solutes on the activity of zinc in dilute solution with molten bismuth in the range 450° to 650°C. 1,2 The cells were of the type The experimental procedures have been described previously.1 In the course of studies conducted in the bismuth-rich corner of the systems Bi-Zn-Au and Bi-Zn-Cu, marked discontinuities were observed in the electromotive force-temperature relations for a number of the experimental compositions. Above the discontinuity temperatures, the relations, which were linear, exhibited slopes similar to the binary alloy of the same mole fraction zinc, as shown in Figs. I and 2. Below the discontinuity temperatures, the slopes were markedly different, but the relations remained linear. In general, as the amount of the third eletnent was increased, the slope of the lower portion of the relations tended to become less positive. The slopes of electromotive force-temperature relations reflect the entropy of mixing of zinc and, therefore, the occurrence of a discontinuity marks the transition between two different equilibrium situations involving the solution of zinc. A number of other investigators3-5 have used such observations to determine liquidus boundaries in binary alloys. Since the upper portions of the ternary electromotive force-temperature relations of this study had the same slopes as the binary alloys, the discontinuities are interpreted as marking the transition between the single-phase liquid region and the underlying two- and three-phase regions. Reference to the Zn-Bi equilibrium diagram6 confirms that the binary alloys were single-phase liquids at the experimental temperatures. Fig. I shows the electromotive force-temperature relations for the alloys containing Bi-Zn-Au and Fig. 2 shows similar relations for the Bi-Zn-Cu alloys. In the lower portion of each figure, the temperature of the discontinuity is plotted vs the mole fraction of the added solute at the various levels of zinc concentra- tion. Cross-plots from these curves at constant temperature permitted the construction of the partial liquidus surface isotherms shown in Figs. 3 and 4.

Jan 1, 1967

The areas of concern lay in the processing of, and the subsequent hearing into, Waihi Gold's resource consent applications to extend Martha Mine. The proposed amendments to the Resource Management Act 1991 might see the introduction of contestability in the processing of applications - which would have assisted Waihi Gold; and the use of commissioners to hear the applications, with a right of appeal to the Environment Court on points of law only. It is also proposed to have major applications heard directly by the Environment Court. If Waihi Gold's applications had been heard at first instance by the Court, the delays in time and associated costs would have been reduced. However a hearing by commissioners only would not have been satisfactory, there being no right of appeal against the conditions of consent, which if implemented as granted by the Councils would have had a significant impact on the costs associated with the extended project.

Jan 1, 1998

By M. Vandewalle

What separates the support of mining openings from the support of similar civil engineering structures is the fact that mine openings have to survive large deformations as a result of changing stress conditions induced by progressive mining. Steel fibres impart to concrete and shotcrete a high degree of ductility which not only allows the shotcrete and concrete linings to absorb important rock movements but also to increase its bearing capacity by a redistribution of the loads. A range of applications will be discussed technically and economically.

Jan 1, 1998

The objective in control blasting is to reduce overbreak to control the final pit wall slope, shaft, drift, ditch, bench, etc. to the final planned excavation limit.

Jan 1, 1991

By W. A. Young

To initiate this project a critical evaluation of the pre-sent phosphate mining industry in the Western phosphate field was conducted. Mines were visited, mine operators were interviewed and pertinent literature studied. Three phosphate mining enterprises were reviewed and mining cost estimates prepared. The report discusses the present state of phosphate processing, rock alteration and location. New ideas and concepts are proposed to improve the recovery of phosphate rock from the Phosphoria formation. The report evaluates two variations to the present phosphate open pit mining methods, which were developed to improve the economics of mining phosphate and to better accomplish necessary reclamation and accelerate the time for environmental recovery. A material handling system using conveyor haulage will eliminate the need for trucks. Terrace haulback utilizes safety benches to haul and dispose of waste in the mined out pit. Ore will be removed from the pit via an inclined, cable-supported mobile conveyor.

Jan 1, 1980

By Raissa Santos Salgado

O refino primário através dos convertedores BOF representa uma etapa fundamental na fabricação do aço. Em meio a um mercado desafiador e competitivo, estabilidade operacional e inovações são necessárias para alcançar qualidade e preços razoáveis. Com o intuito de estudar o sopro combinado através de um modelo físico, similar com convertedor da thyssenkruppCSA 330t, foi utilizada uma análise visual associada a métodos colorimétricos para mensurar a penetração do jato e a melhor configuração de ventaneiras. Com base nesses métodos, encontrou-se a distância banho-lança que reduz o tempo de mistura com menor probabilidade de slopping. A partir dos resultados obtidos no modelo a frio, os parâmetros foram recalculados para a prática industrial.

Oct 30, 2017

By Shaney Gonçalves Mileipe

No contexto atual, os estudos de engenharia de confiabilidade se tornaram cada vez mais essenciais para o acréscimo de disponibilidade das plantas e estabilidade operacional. Este trabalho tem por objetivo, através da metodologia de análise e solução de problemas (MASP) focada em modos de falhas prioritários, reduzir o tempo de manutenção não planejada do processo de Sinterização da Arcelor Mittal Tubarão. Os resultados obtidos concretizaram um aumento de 2% na disponibilidade da planta após a elaboração de um plano para corrigir os modos de falhas críticos, revelando a importância e o potencial de ganho em se investir em estudos de confiabilidade e registro de falhas.

Oct 30, 2017

By Z Chang, S A. Mrozek

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Antamina, Peru is the largest Cu-Zn skarn deposit in the world. Skarn mineralisation is focused around a multiphase Miocene intrusive complex comprising at least eight distinct phases identified by cross-cutting relationships, including truncated veins, xenoliths and chilled margins. Skarn alteration and mineralisation, as observed in drill core, remain open at depths exceeding 2.2 vertical kilometres.Porphyry intrusions occur as four major phases with subphases (from oldest to youngest): P1 (a, b), P2 (a, b), P3 (a, b) and two dykes of uncertain timing named Oscarina-1 and Oscarina-2. P1a is a hornblende-biotite quartz diorite porphyry with pervasive K-alteration, local endoskarn and 30–40 per cent sheeted quartz veins, all of which obscure original igneous textures. P1b dacite porphyry is a minor unit with <10 per cent phenocrysts and <3 per cent quartz veins. P1b cuts P1a; P2 dykes cut both units. P2a porphyritic biotite quartz monzonite contains K-feldspar megacrysts up to 4 cm long, local K-alteration and 2–80 per cent quartz stockwork veins. P2b biotite monzonite porphyry contains approximately 50 per cent phenocrysts and typically <10 per cent quartz veins. P3a (brown groundmass porphyry) and P3b (coarse phenocryst porphyry) are minor in volume and extent, and both cut P2 bodies. Oscarina dykes comprise two separate but parallel bodies. Oscarina-1 is a feldspar-phyric rhyolite porphyry, while Oscarina-2 is an intensely chloritised andesite porphyry. Oscarina-1 has a U-Pb (laser ablation inductively coupled mass spectrometry (LA-ICP-MS)) age of 10.1 ± 0.1 Ma, whereas P2 U-Pb zircon ages (LA-ICP-MS) range from 10.0 ± 0.2 Ma to 9.9 ± 0.3 Ma.All the intrusive phases contain quartz veins, with P1a and P2a having the most intensive K-alteration and most abundant quartz veins ± endoskarns. Each phase may have contributed to mineralisation at the right depths and within favourable wall rocks (ie marble) during uplift of the Antamina structural block. Therefore, a model of multiple intrusions during continuous uplift explains the vertically extensive (>2.2 km) skarn and mineralisation at Antamina.CITATION:Mrozek, S A, Chang, Z and Meinert, L D, 2015. A model for the intrusive sequence and Cu-Zn skarn formation at the Antamina deposit, Peru , in Proceedings PACRIM 2015 Congress, pp 423–430 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

Northern Iron Ltd (NIL) is an Australian listed company that recently brought the historic Sydvaranger open pit Magnetite Mine (the Project) in Northern Norway successfully back into production. NIL made the decision to operate the Project on an owner mining basis, due to limited large scale mining expertise amongst Norwegian mining contractors, a long mine life, a limited range in planned mining rate and to minimise costs. As a new mine operator in a country where labour practices are strictly regulated, there was the desire to reduce the risk associated employing and managing skilled personnel. This was achieved by coupling the purchase of the required mining equipment from the original equipment manufacturer's (OEM) regional dealers with OEM supported Maintenance and Repair Contracts (MARC). This paper examines the process that was followed to implement an owner mining operation in a short time frame; approximately 12 months from the initial requests for quotation to actual delivery of mining equipment to site, and some of the challenges faced. By following a formal and well-tested process, not only was the implementation achieved in the set time frame, but significant value was added through the cost savings achieved in the equipment purchase price and MARC rates that were negotiated through this process.

May 1, 2010

By Sergio N. Monteiro

Polymeric composites reinforced with natural fibers are increasingly been used in several engineering applications, from automotive parts to building construction elements. In addition to the relatively low cost, the natural fibers are also appraised by their renewable and biodegradable characteristics. Fibers extracted from the crust of coconut fruits, also known as coir fibers have been investigated for a possible use in composite materials. In the present work, the coirfiber/polyester matrix interfacial strength was evaluated by means of pullout tests. The variation of the pullout tensile stress vs. the embedded coir fiber length permitted to determine the critical fiber length and, thus, to calculate the interfacial strength. Observations by SEM complemented the results from pullout tests, indicating that coir fibers have a potential for application aspolymeric composites that could replace conventional materials such as wooden and gypsumpanels.

Jan 1, 2006

There are many ways to classify structural slurry wall elements, but the DFI committee chooses to limit these descriptions to three functional requirements, namely: design function, plan configuration and type of panel reinforcement. (See Figure 1 in Part IV for panel classification). Slurry walls can function as: 1. Curvilinear or linear elements for temporary and/or permanent structures to resist lateral forces transferred from the ground, water, earthquakes and various surcharge loads. 2. Load bearing elements in various plan shapes to resist vertical forces. 3. Combination Elements to resist combined forces under conditions 1 and/or 2. For example, elliptical shafts with various openings for tunnels and conduits have been commonly used for deep excavations.

Jan 1, 2005

Paper written on project work carried out in partial fulfilment of BSc Engineering (Mining) The aim of this project is to determine whether certain pillars occurring within the no. 1 shaft and no. 2 sub-shaft ground are feasible for extraction. The extraction of these pillars is essential in prolonging the life of Kloof Main Shaft as its VCR resource becomes depleted. Extraction of these pillars will require a combination of designs and factors, with rock mechanics and ventilation being the main considerations. Primarily for the pillar extraction, an initial production target of150 kg gold, mine able in one year from commencement of ?opening up? was set. The planned target has been exceeded and the feasible pillars identified are expected to yield an additional 1 390 kg of gold to the shaft?s production profile. However, not all the required ventilation designs have been completed to date, the reason being that at the time of the project, many of the pillar areas were inaccessible and thus ventilation conditions are unknown. This project is therefore an ongoing process and will require further design once all targeted pillar areas have been opened up. A preliminary costing analysis of the pillar mining was performed and it was found that all targeted pillars with the exception of 38?61 pillar are profitable.

Jan 1, 2005