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By J. D. Dixon

This Bureau of Mines report describes the results of an investigation for developing and applying procedures for stabilizing excavations openings in highly yielding ground. The approach developed in this report involves nonlinear modeling of the progressive relaxation of the zones of rock mass around the excavations opening where Coulomb criterion of failure is exceeded. Stresses are calculated by using a computer code; Coulomb-failure condition is examined for both intact rock and joints (using strength parameters [~] and c). The rock mass in the failed zones is relaxed by reducing the Young's modulus of the rock based on an empirical formulation that is a function of the shape of the opening and the extent of the failed zone. In addition, the material in the failed zone is assigned reduced strength paramters 0' and c'. The limiting (or convergent) relaxed zone is obtained through an iterative process by manually changing the rock modulus and the strength parameters between iterations. Support pressures are computed by applying forces normal to the excavation surface. The approach is applied to the analysis of stability and support requirements for an entry in a longwall coal mine.

Jan 1, 1985

By Satya Harpalani

The four most important parameters controlling the flow of gas in coal are the gas content, permeability, diffusion coefficient and cleat characteristics. Estimates of these and, more importantly, a knowledge about the variation in their values over time are required for simulation of long-term gas production. This paper describes experimental techniques to determine each of these, along with their time dependency, under simulated in situ conditions. It is shown that the permeability, diffusion coefficient and the cleat aperture values are not constant as usually assumed to be. There is a significant variation in their values as a result of changes in the microstructure of coal associated with release and flow of gas.

Jan 1, 1995

By K. V. Raj, A. T. Weakley, A. L. Miller, D. A. Parks

Diesel particulate matter (DPM) is a common and well-known health hazard in the mining environment. The current approved method for monitoring both the organic and elemental carbon (OC, EC) portions of DPM is a laboratory method with a turnaround time of approximately one week. In order to evaluate exposure levels and take corrective action before overexposures occur, a portable real-time device capable of quantifying both OC and EC is needed. To that end, researchers from the National Institute for Occupational Safety and Health (NIOSH) designed and tested a device based on narrow bandpass optical filters that is capable of targeting infrared absorbance bands associated with DPM. Five optical bandpass filters were chosen based on previous work quantifying DPM using Fourier-transform infrared (FT-IR) spectrometry. The resulting device, referred to as a filtometer, is optimized to exclusively determine DPM and could serve as a cost-effective, field-portable alternative to laboratory-grade FT-IR analysis and instrumentation. The performance of the filtometer was investigated by calibrating FT-IR data from DPM (dependent variable) to the filtometer spectra (predictor variables) using a partial leastsquares (PLS) and ordinary least squares (OLS) approach. The square of the correlation coefficient and root-mean-square error of cross validation m

Mar 2, 2022

By Paula Rodrigues Caumo

A aterosclerose é um termo geral relativo a diversas doenças relacionadas ao espessamento e perda de elasticidade da parede arterial. Atualmente os maus hábitos alimentares, combinados ao sedentarismo, podem levar a ocorrência de elevados níveis de colesterol na corrente sanguínea. Este fato aumenta o risco de obstrução dos vasos sanguíneos, limitando o fluxo do sangue para o coração. Desta maneira, para desobstruir o vaso sanguíneo e manter o lúmen arterial aberto é colocado um stent. Os stents são redes, normalmente de ligas metálicas, que servem para desobstruir os vasos sanguíneos. O tratamento de doenças das artérias coronárias e periféricas usando stents metálicos tem sido adotado nas intervenções médicas nos dias de hoje. No entanto, surgiram argumentos que indicavam os benefícios de remover o stent após este ter feito a desobstrução, originando desenvolvimento de stents biodegradáveis. Estes exigem propriedades mecânicas adequadas, biocompatibilidade adequada, garantindo uma baixa toxicidade dos produtos de degradação. Com isso, o objetivo deste trabalho é o estudo preliminar sobre stents metálicos biodegradáveis, como ferro puro, magnésio. Além disso, avaliar se os mesmos são adequados para aplicação à stents biodegradáveis, avaliando as propriedades mecânicas dos metais, biocompatibilidade e toxicidade dos compostos degradados ao longo do tempo de implantação.

Aug 17, 2017

By A. G. Journel, CH. Huijbregts

"Centre de Morphologie MathématiqueSpecial problems arise in the evaluation of lateritic-type orebodies (Ni-Co, bauxite) or, more generally, orebodies affected by surface weathering. In this type of orebody, the vertical grade distribution shows, from the hangingwall downwards, a systematic increase followed sometimes by a certain decrease, or vice-versa. These trends appear together with irregular variations from one drill bole to the other.The problem is to characterize a vertical structure that is representative not only of the drill hole but of an entire panel or zone of influence, in order to define mineable thicknesses for given cut-off grades. The vertical grade distribution observed on the drillhole is replaced by a new curve, called 'derive' (drift), which is computed by 'universal kriging'.Once the vertical study is completed, new 'service-variables' are defined in the horizontal plane, such as mineable thickness and the corresponding average grade, economical functions (combination of the grades of several minerals). The local and global estimation of these variables can then be performed by a simple bi-dimensional kriging plan. The global estimation is summed up by several tonnage-cut-off grade curves.The practical valuation according to the above scheme of a New Caledonian lateritic nickel orebody is presented."

Jan 1, 2014

By R. W. Bruce, K. W. Downes

"IntroductionSULPHUR production in Canada from all sources for the year 1953 amounted to about 375,000 tons. Except for 16,000 tons of elemental sulphur derived from natural gas, this production was in the form of by-product pyrites, liquid sulphur dioxide, and sulphuric acid. In the same year, Canadian industry imported 359,000 tons of elemental sulphur from the United States. The cost, including transportation charges, to Canadian consuming plants ranged from $35.00 to $45.00 per long ton, depending upon location.Although most of the sulphur consumed is used in the oxidized form it is often most convenient to buy sulphur in the elemental form, and convert it to sulphur dioxide or sulphuric acid in situ as required. This is because elemental sulphur is easily shipped and stored, weighs only half as much as an equivalent quantity of sulphur dioxide and one-third as much as the corresponding quantity of sulphuric acid, and is readily converted to these forms in a sulphur burner. A process, therefore, which could economically recover elemental sulphur from sulphide ores would be most attractive.Since the turn of the century, notable improvements have been made in extractive metallurgy, but until recently only limited attention has been paid to the possibilities of elemental sulphur recovery. This has been due to the plentiful supplies of cheaply mined Frasch sulphur which have been available on the world markets."

Jan 1, 1955

By E. T. Knight, John D. Gill

IN ITS capacity for service to the public the oil industry is truly gargantuan. But it is only in this respect that the industry is the voracious, many-headed, many-armed and many-handed creature it has been so often painted by those who know it not too intimately and only from the outside. Contrasted sharply with the immensity of the service rendered is the relatively modest share of the national income which has gone to those who provided the tools and the mental and manual labor with which the service was performed. No doubt the relative meagreness of the re- ward was the result of a combination of fortuitous circumstances respecting the nature and accessibility of the industry's raw material and the extensive development and application of the most advanced technology, spurred by an intense competition.

Jan 1, 1940

By B. K. Shibler, I. S. Solet, H. W. St. Clair

"This study was undertaken to provide a more adequate knowledge of the chemistry of the sulfide volatilization process for recovery of tin from low-grade Bolivian ores. The investigation was partly supported by the Department of State under its program for scientific cooperation with South American republics.The results of this investigation demonstrate the conditions under which cassiterite (Sn02) may be converted to stannous sulfide by reaction with pyrite or sulfur vapor. Quantitative data are given on the rate of sulfidization and on the vapor pressure of stannous sulfide.INTRODUCTIONAlthough the United States is the world's largest consumer of tin, virtually no tin ores occur within our national borders. Most of the world's tin supply comes from alluvial deposits in the Far East and in Africa, The major sources of tin ores are Malaya, Indochina, Bolivia, Belgian Congo, Nigeria, Thailand, Burma, China, and the United Kingdom. Bolivia is the only important source of tin in the western hemisphere. It was the chief source of tin f or the United States during World War II. The Government-owned tin smelter at Texas City, Tex., was built primarily for smelting Bolivian ores and depends largely on Bolivian ores for its operation. Bolivia is the only major tin-producing country in which the tin ores occur as vein or lode deposits requiring underground mining. Most of the tin from the Far East and Africa is mined by dredges from alluvial or placer depos its. It is recovered as a high-grade concentrate of cassiterite relatively free from impurities. The tin minerals in the lode deposits are more intimately associated with other minerals and more difficult to separate into a clean concentrate. Furthermore, a large part of the tin in the original ore is lost during concentration. The ores as mined contain only a few percent of tin, so they must be milled to separate the gangue minerals and produce a concentrate containing 30 to 40 percent tin before they are shipped to the smelter. The losses of tin that occur during milling vary from 18 to 65 percent. The average recovery of tin from Bolivian ores is probably 50 to 60 percent."

Dec 1, 1954

By N. A. Karl, D. R. Wilburn

"This summary of international mineral exploration activities for the year 2016 draws upon information from industry sources, published literature, SNL Metals & Mining (SNL), an offering of S&P Global Market Intelligence (New York, NY), and specialists in the U.S. Geological Survey (USGS) National Minerals Information Center. Three types of information are reported and analyzed in this annual review of international exploration: 1) budgetary statistics expressed in U.S. dollars provided by SNL; 2) regional and site-specific exploration activities that took place in 2016 as compiled by the USGS and 3) regional events and legislation that affected exploration activities including economic, social and political conditions, which were derived from published sources and discussions with USGS and industry specialists. Commodity and regional compilations are presented in this summary. Because multiple sources were used to develop commodity and regional compilations, statistics may vary depending on the source and type of data that are being reported. The SNL data summarize budget estimates for worldwide exploration activities in 2016 for 30 nonfuel mineral commodities and metal alloys, based on company surveys. Surveys focused on precious metals (gold, platinumgroup platinumgroup metals (PGMs) and silver), base metals, (cobalt, copper, lead, molybdenum, nickel, tin and zinc), bulk commodities (bauxite, chromite, iron ore, manganese, phosphate and potash) and other commodities (aluminum, antimony, diamond, graphite, heavy-mineral sands, lithium, niobium, rare-earth elements (REEs), scandium, tantalum, tungsten, uranium, vanadium and yttrium). Information on uranium exploration activities was included in SNL’s survey for the first time in 2007. Data on lithium, niobium, phosphate, potash, REE and tungsten were compiled for the first time in 2010, and scandium, vanadium and yttrium were added in 2014 because of their increased topical significance. Since 1999, companies with exploration budgets of $100,000 and greater were included in the SNL surveys. SNL budget estimates exclude coal, and oil and gas. The 2016 SNL mining company survey compilation was reported by SNL to include an estimated 95 percent of the world’s nonfuel mineral exploration budgets. The 5 percent that was not covered was accounted for by companies that chose not to participate in the SNL survey, private companies that do not publish their budget data and government-funded exploration activities."

Jan 5, 2017

By S. Vézina

"Environmental issues have evolved considerably over the last two decades. The main contributing factors, to name a few, have been the changing values of modern societies, the globalization of trade and its linkage to environment, evolution and accessibility of information/ communication technologies, better educated populations, climate change, longrange transport of toxics, and the increasing influence of non-governmental organizations (NGOs) and multistakeholders.As well, environmental management of mining operations had to be realigned in order to meet these new realities and to respond to more elaborated regulations oriented towards sustainability. Environmental management systems (EMS) have been introduced not only to meet the assurance of conformance to regulations but also to prevent pollution and to apply the continuous improvement of mining processes. EMS models have been developed and certification to international standards (e.g. ISO 14 001) is a common practice.Globalization has imposed challenges and additional requirements to environmental management. Developing a mine in emerging countries implies dealing with international agencies, local communities, and a variety of government infrastructures to obtain a “license to operate.” This paper presents the structure of Cambior’s EMS and how it was adapted and implemented in the company’s operations in South America."

Jan 1, 2006

By David A. Monaghan

On January 14, 1974 a fire occurred in the 3 East mains of the Joanne Mine of Eastern Associated Coal Corp. in Rachel, West Virginia. The mine was evacuated without injury and sealed completely at the surface within 24 hours. It was decided by the coal company along with the U, S, Bureau of Mines, the West Virginia Bureau of Mints and MESA that remote sealing of the fire zone would be attempted. This report summarizes the remote sealing effort and those activities directly related to the remote sealing effort. This chapter provides a brief history of previous remote sealing attempts, a description of the recently developed remote sealing system and a description of the Joanne Mine operation as it related to and affected the remote sealing effort.

Jan 1, 1975

By I. L. Grigorova

As a result of the main processes of the limestone treatment ? sawing, buffing and polishing, a technological waste is usually obtained. These final tailings consist of a water suspension with highly variable solid phase content and granulometric composition. Since the waste is conducted to a tailing pool or another place, this leads to environment pollution. In this work the slurry waste generated during the limestone processing in a Bulgarian limestone manufacturing company was characterized. The chemical composition, particle size distribution, solid phase content, whiteness, yellowness, abrasion, specific surface and density were determined. The possibility of obtaining building/construction materials from limestone processing waste was studied in a laboratory scale. The technological tests included thickening, filtration and drying of waste products. Continuous operation laboratory thickener was used. Coagulant Accepta® 8302 (aluminum sulphate solution) and anionic flocculant Magnafloc® 155 were found to be the most effective in the sedimentation of the products. Filtration tests were performed using a laboratory pressure filter. Drying tests were carried out in laboratory facilities using the direct heating method. On the basis of the laboratory results a technology for limestone treatment waste was developed. A production line for building materials from limestone slurry was set up. As a result the manufacturing company has a possibility to use circulating water.

Jan 1, 2014

By Jim Bruce, Peggy Hagerty Duffy, Mary Ellen Large, Allen Cadden

"Over the past 40 years, Deep Foundations Institute (DFI) has executed its mission “to bring together multi-disciplined individuals and organizations to find common ground and create a shared vision and consensus voice for continual advancement in the deep foundations industry”. Like DFI, micropile technology began a significant growth path in the mid-1980s. This paper highlights how DFI’s mission was executed in the deployment and expansion of micropile technology.INTRODUCTIONMicropiles are small diameter foundation elements constructed using specialty drilling and grouting methods. Micropiles have evolved since their introduction into the North American market in the 1970s from being lightly loaded (less than 30 kips) elements used primarily for remedial applications, to today’s high-capacity, often hybridized foundation systems, for both remedial and new-build projects. Micropiles now occupy a substantial market segment in North America.For 40 years, DFI has aimed to be the forum for discussion of all issues related to deep foundations design and construction. DFI now supports 21 technical committees and working groups on all deep foundations technologies and has expanded to include regional chapters in Europe, India and the Middle East.Several key steps are required for the successful execution of DFI’s mission, including identifying a need, engaging dedicated and knowledgeable people, developing effective vehicles and resources for information sharing, cultivating stakeholder contributions and advancements, stimulating influence/impact on deep foundations market, and expanding approaches to continue progress. Pile drivers in New York City (the original organizers of DFI) positively affected their market using these same steps: they recognized a specific need, gathered the people who could affect change, convened a discussion forum (which is common today, but was innovative at the time), defined tasks to address the issues, and influenced their market by improving means, methods and owner perception of their services. These forward thinking, proactive members created a mechanism for communication among all related parties that would advance the profession by improving safety, quality and value of pile driving construction.Micropile technology has evolved in the United States and around the world for the past four decades. The accumulated efforts of DFI and other, similar organizations such as The International Association of Foundation Drilling (ADSC) have contributed to this evolution. The advancement of the micropile industry – and consequently the micropile market – has been intimately tied to the execution of the mission of DFI."

Jan 1, 2017

By J Zhang, R Dimitrakopoulos

A two-stage stochastic mixed integer non-linear program is formulated for a mining complex to optimise strategic and tactical plans. The objective is to find the near optimal decisions for a mineral supply chain in the context with uncertainties in both ore supply and the commodity market (price and demand). The endogenous spot price in the commodity market and long-term sales contracts are considered in the formulation of the mining complex’s optimisation model and an ad hoc heuristic is developed to deal with the throughput – and head-grade-dependent recovery rate in processing plants. Numerical results indicate that the proposed heuristic is effective and efficient in numerical tests. Based on the proposed model and heuristic, a long-term contract design strategy is proposed for making decisions on the contract price and strategic investments. A shadow price based method is also proposed to evaluate the existing mining schedule.CITATION:Zhang, J and Dimitrakopoulos, R, 2014. Optimising a mineral supply chain under uncertainty with long-term sales contracts, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 25–32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By R Williams, M Baxter, D Zink, R Cunningham

The purpose of this paper is to discuss the efficient operation of a tailings dewatering circuit comprising a thickener and filter press through proper control and automation. It is common to see thickeners and filter press circuits each with their own control systems. This can cause multiple issues when trying to increase efficiency and reliability of the tailings management process. By automating the thickener and filter press controls, you are eliminating any delays and inconsistencies caused by human error and process variations. When done properly the system can maintain a consistent product as the feed characteristics change. Previously, operators would have to monitor the process parameters and adjust the system accordingly. This can now be accomplished using state of the art process control equipment that continuously monitors and adjusts critical variables using Programmable Logic Controllers (PLC) and Proportional Integral Derivative (PID) loops. The paper will detail the control theory used to maintain these systems, highlight other benefits of having a fully integrated plant such as predictive maintenance and remote diagnostics as well as present examples of how these have been implemented in field examples.CITATION:Baxter, M, Cunningham, R, Williams, R and Zink, D, 2018. Tailings process optimisation through automation and controls integration, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 416–421 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By Jeannine Wendy Salas Huamán

Dado que la empresa minera tiene como objetivo el fortalecimiento de la responsabilidad social y ambiental para la AID (Puno), se implementa un programa de actividades que responda a la responsabilidad social y ambiental. En ese sentido, el presente texto describe la capacitación como una herramienta de una logística -en tanto se entrene a los pobladores de la AID para que puedan brindar servicios a la minera, se concilie la explotación minera con la población mediante la logística y se establezca una alianza con los pobladores formándolos como proveedores, de forma que se obtenga una ganancia conjunta.

Nov 1, 2013

By Sheshang Singh Chandel, Prvan Kumar Katiyar, Navneet Singh Randhawa, Prince Kumar Singh

Mineral process wastes, such as metallurgical slags nowadays, are of significant metals and materials resources in the circular economy. The usability of iron-making slag is well established; however, steel slag still needs to be utilized due to various physicochemical constraints. In this context, we have reviewed the global steel slag generation, processing, characteristics, and potential application with suggestions for futuristic possibilities to address the technical, economic, and environmental aspects of steel slag recycling. The steel slags inherit characteristics from ore chemistry and their processing routes, which may be Blast Furnace-Basic Oxygen Furnace (BF-BOF) or Direct Reduced Iron-Electric Arc Furnace (DRI-EAF) steel-making routes with/without treatment in a Ladle Furnace (LF). The average generation of slags in BOF, EAF, and LF processes accounts for 110 kg, 70 kg, and 40 kg per tonne of steel, respectively. Considering global steel production of 1878 million tonnes in 2020, the associated slag by-products possess a significant resource of major components like FeO, CaO, SiO2, Al2O3, etc. Selecting a recycling technique depends on the slag's end use, logistics, and physicochemical characteristics. BOF and EAF slag are used ~ 48% in road construction applications and ~ 10% for industrial specific metallurgical use. EAF slag is preferred as cementitious material as compared to BOF. Hot-stage modification of BOF slag has emerged as a preferred method to achieve desired chemical and subsequent mechanical properties for end use. BOF slag has high carbon dioxide sequestration potential for in-plant remediation among steel slags.

Nov 20, 2023

By D. W. Boydell

The response of reclaimed gold tailings to acid leaching was investigated in the laboratory, followed by a pilot-plant program in which the operations of CCD, CIX and SX were tested with plant feed material. These results formed the basis for the design of the extension to the existing uranium plant at Blyvooruitzicht Gold Mine, commissioned in July 1977. This circuit consists of slimes-dam reclamation by bucket-wheel excavator at a rate of 100,000 t solids per month, acid leaching in pachucas, a five-stage CCD washing section, two parallel C1X absorption columns and two elution columns, SX and an ADU precipitation section. Barren solution is recycled to the CCD section as wash and to the repulper at the slimes dam. The performance of the plant during the first year of operation is compared with the predictions on which the plant design was based. Rated capacity was achieved within three weeks of start-up at a nominal dissolved uranium recovery in the ion-exchange section of around 98%. Owing to recycle, the over-all recovery in the ion-exchange and solvent extraction sections is somewhat higher than this figure.

Jan 1, 1979

By Ko-ichiro Ohno

It is recently recognized that the iron reduction and melting as well as the slag separation of a composite of granular iron ore and coal are completed in a very short period of about IO minutes when the composite is rapidly heated up to approximately 1673K. These phenomena are expected to be applied to a new iron-making process. The mechanism of iron ore reduction and iron-slag separation during rapid heating has not yet been revealed and the fundamental research has just started. Carburization of the reduced iron is regarded as one of the most important steps in this process. In the present work, the composite was prepared from four kinds of coal or graphite as a carbon source and electrolytic iron powder as a completely reduced iron ore. The temperature at which the liquid formation and iron carburization occurred was monitored. Direct observation of smelting reduction behavior was made by a confocal laser-scanning microscope combined with the infrared image-heating furnace to clarify the effect of molten ash on iron carburization. It was found that the meltdown temperature of composite became lower as the melting temperature of coal ash decreased. From the observed result, it was presumed that the liquid slag would act as an important media for the carbon transfer from coal to iron. The carburization mechanism during the smelting reduction was estimated as follows. When slag containing iron oxide melted down and contacted carbon, iron oxide in the slag was reduced and the formation of the metallic iron particle as well as the its carburization occurred simultaneously at the slag-carbon interface. Carburized iron particle was carried from slag- carbon to slag-iron interfaces due to the slag convection flow caused by the difference of the interfacial tension between the carbon-slag and iron-slag interfaces. Carburization of reduced iron could proceed with a repeat of the above-mentioned process.

Jan 1, 2003

By J. H. Welsh

This Bureau of Mines report presents guidelines to be considered in the design, installation, and operation of environmental mine monitoring systems in underground coal mines so as to enhance safety in the U.S. mining industry. A review of the current status of mine monitoring in the United States is also provided.

Jan 1, 1987