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"Here, we statistically proved that giant earthquakes occur at lunar phases specific to each subduction zone. Enough attention during the lunar period, especially when seismicity is occurring, will significantly reduce damage from giant earthquakes. Two case studies in which giant earthquakes occurred after seismicity in dangerous lunar phases were discussed, and the mechanisms underlying why giant earthquakes occur around neap tide at some subduction zones were explained by prohibition of giant earthquake occurrences due to high strain rates at spring tides at N–S subduction zones. The prohibition was statistically proven for uniaxial creep tests on Inada granite with slight stress disturbances. INTRODUCTIONIn previous studies, we showed that from 1900 to present, giant earthquakes (MW ??8) have occurred at lunar phases specific to each subduction zone (Fujii & Ozaki, 2012; Ozaki & Fujii, 2012). Although we later proposed a possible reason for these occurrences, the study lacked statistical analyses (Fujii et al., 2013). Therefore, this paper shows the results of such statistical testing and presents case studies for the Tohoku 2011 and Chile 2014 events, thereby providing updated data on giant earthquakes through July 2014."

Jan 1, 2015

By M. Marchese

It is no secret that scarcity of fresh water is an issue that at a global level in the years to come will have a major impact on the business landscape. A number of projects, beyond the mining sector, could remain on paper only due to this. At the same time, this situation is seeing the rise of new business opportunities, such as development of technologies for more efficient usage of water, water recycling, and desalinization of sea water. Despite that most of Chilean mining facilities are located in the driest area of the world, business has developed strongly and actively for more than a century. However, the negative effect on the water reservoirs and the environment is, lately, resulting in the reduction of the authorized water rights. Holding Water Rights for any given volume does not guarantee that the resource will be available when needed. A recent report from the United Nations on global climate change indicates that global warming can be directly related to changes in the natural and human environment. Chile would not be an exception. The reduction in snow levels in the high Andes and reduced rainfall during the so called "Bolivian winter", have directly affected the replenishing of the underground water reservoirs in the lower parts of the valleys, where most of the extraction of the resource takes place. Mining facilities shall be designed to reduce potential environmental effects, using proven technologies, and considering the best practices available. These measures shall constitute a complete structural framework for the environmental impact assessment (EIA) of the Project. The measures to prevent and mitigate the impacts on the water resources shall be considered during the design stage of a mining project. Current and future mining projects in Chile are conscious that the increasing pressure on the limited water resources is becoming unsustainable, and are already facing the water scarcity and social pressure by implementing sea water desalination plants, including long pressurized pipelines to the mine sites (e.g. Escondida, Candelaria, El Morro, Regalito). This paper presents, in summary, an analysis of the present and potential future scenarios.

Jan 1, 2007

By R. S. Shoemaker, F. W. McQuiston

CARLIN GOLD MINING COMPANY 1974 Operating Data to October MINE LOCATION: 40 miles from Elko, Nevada ORE DESCRIPTION: Gold with minor amounts of mercury occurring in siltstone and carboniferous limey shales. TYPE OF MINE: Open pit ORE HAULAGE TO MILL: By trucks up to a distance of 12 mi1es MILLING CAPACITY: 2500 tons per day ORE GRADE: 0.20 oz per ton oxide ore 0.25 oz per ton carbon type ore PRODUCTS: Gold bullion 993 fineness, by product quicksilver RECOVERIES: Oxide ore 887'0 Carbon ore 83% POWER FOR GRINDING: 7 Kwh/T POWER, other than grinding: 14 Kwh/T WATER SUPPLY: Pumped from wells 2- 112 miles through 13,000 ft of 8" buried pipe 6 ft underground. Consumption 0.60 tons of new water per ton of mill feed. TAILINGS: By 10" woodstave pipe a distance of 2500 ft to mine waste filled dam. RUNNING TIME: 10 ft x 10 ft mill on oxide ore, 98% 7 ft x 8 ft mill on carbon ore, 937'0 Principal causes of lost time, power outages and problems of feeding gaseous chlorine to carbon ore agitators. LABOR, TONSIMAN SHIFT: See detailed data sheet ILL BUILDING DESCRIPTION: Framed structural steel with sandwich type walls of marine plywood, then packaged pre - fabricated insulation and outer sheeting of galvanized corrugated steel.

Jan 1, 1975

By V. I. Lakshmanan

The growing concerns on process efficiency, escalating operating and capital costs along with environmental and social concerns of using conventional technology for extracting gold and titanium dioxide demand an in-depth understanding of the fundamentals and a broader understanding of the various process steps involved. This will allow development of efficient process flowsheet for product recovery and compliance with regulatory guidelines. This paper will discuss our recent developments in mineral processing and hydrometallurgical technologies to recover gold and titanium dioxide from a wide range of feed materials including ores, concentrates and tailings.

Sep 1, 2012

By J. R. Tickner

"Gold is conventionally analyzed using fire-assay or other destructive chemical methods that impose significant sample preparation, OH&S, and skilled labour requirements. Developed over the past 15 years by the CSIRO, PhotonAssay provides a new approach. A high intensity, high-energy x-ray source is used to activate atoms of gold and other elements in bulk mineral samples. The resulting activity is counted to automatically, accurately and rapidly determine metal grade. Samples weighing 0.5–1.0 kg can be measured in a few minutes with minimal preparation. As the method is matrix-agnostic, traditionally hard-to-assay materials such as highly refractory ores, carbon pulps and copper concentrates require no special treatment. We present the status of commercial PhotonAssay systems being developed by Chrysos Corporation. The first unit with a throughput of up to 80 samples per hour is to be deployed in an Australian assay laboratory in late 2017; smaller systems suitable for providing real-time assay directly at the mine-site will be progressively rolled out from mid-2018. Performance results from extensive testing using both mine-sourced and standard reference materials are presented, demonstrating the sensitivity and accuracy of the method. Implications for replacing conventional gold assay in exploration, mining and processing operations are discussed.INTRODUCTION Accurate methods for assaying ore grade are essential throughout the exploration, mining and mineral processing value chain. The discovery and evaluation of new ore deposits, reserve and resource definition, mine operations planning, ore processing, metal accounting and product quality evaluation all rely on accurate measurement of the valuable metal content of bulk materials. The analysis of gold presents particular challenges, stemming from the very low concentrations at which commercial operations run (often part-per-million (ppm), or equivalently one gram-per-tonne levels or below), and the highly heterogeneous nature of many gold deposits. These challenges mean that any analytical method must have high sensitivity and be capable of measuring large-mass samples. The most widely used quantitative analytical method for gold is fire-assay (Hoffman, Clark and Yeager 1998). An initial ore sample typically weighing several kilograms is dried, crushed and pulverized to allow a small sub-sample (10–50 g is common) to be representatively drawn. The sub-sample is mixed with flux, litharge (lead oxide), a reducing compound and other reagents. The mixture is fired at a temperature of 1000–1200°C until molten. After cooling, the slag is removed and the lead button containing any gold present in the sample is remelted in a porous cupel. The lead is absorbed into the cupel, leaving a gold prill which is either weighed directly, or dissolved in acid and analysed via atomic absorption spectroscopy (AAS) or inductively coupled plasma spectroscopy (ICP or ICP/MS)."

Jan 1, 2017

By N. Kubo

Sumitomo Toyo Copper Smelter and Refinery was commenced in 1971, and its production capacity of sulfuric acid was 550tpd at the beginning. In 2001 Toyo Copper Smelter and Refinery projected to expand its copper production capacity to 450,000tpy, and now the project is still in progress. To achieve this expansion project, 4,000tpd of sulfuric acid production capacity is necessary to the acid plant. So as a part of this project, the construction of the new converting and absorbing line and the improvement of the existing converting and absorbing line were carried out from 2001 until 2005. Then the production capacity of these 2 lines has already reached the target, 4,000tpd of sulfuric acid. Moreover, at the design of the new line, we adopted several latest technologies and materials in order to construct the world's leading acid plant. Basing on the operation performance of the new line, we have improved the existing line in 2005. Both of these 2 converting and absorbing lines are working quite well and contribute to big energy saving and excellently stable operation. Cu2007

Jan 1, 2007

By Bijan Taheri, Behrouz Maghsodi, Monireh Heshami, Reza Kohan

A common problem recently encountered with the increase in the rate of input feed at Enrichment Plant 2 of the Sarcheshmeh Copper Complex is the loss of value to the tails, translating to lower recoveries. The feasibility of the direct transfer of part of the high-grade concentrate from rougher stages to an appropriate position along the circuit was studied, and two positions were proposed for direct transfer of the concentrate. One position was the feed flow into cleaner cells, and the other was the feed flow into the recleaner cell. The results indicated that transferring the concentrate from the first unit of the rougher stage to the feed flow into the cleaner cells was feasible, with no limitations, while the second position required the installation of a set of hydrocyclones. It was found that the transfer of concentrate to the proposed positions not only addressed the problem of limited cell capacity, resulting in debottlenecking of the circuit, but also improved metallurgical separation efficiency up to 1.4%.

By Wenxue Chen

This paper presents a new type of bolt with full thread and uniform strength, and fabricated with a Glass Fiber Reinforced Polymer (GFRP) bolt-making machine designed by the authors. The mechanical performance of the new bolt is assessed with strength tests conducted with the bolt in acid, alkaline and saline water conditions, with increasing concentration. The purpose is to test the new GFRP bolt?s mechanical performance in harsh conditions, especially metal mines with acid or alkaline environments. Comparison of the color, weight, size and antistatic ability of the GFRP bolt before and after it is immersion in solution is presented. Changes in tensile and shear strength, torsion, and anchoring force were evaluated in the laboratory. The results show that the mechanical properties of the GFRP bolt are more sensitive in alkaline than in acid and saline water. However, the loss ratio of mechanical properties of the GFRP bolt is very small according to the results of tensile and shear strength, torsion and anchoring force. The new bolt can be useful for applications in acid or other harsh mines.

Aug 1, 2013

By Tim C. Webb

For almost 350 years, industrial rocks and minerals have been produced, used locally and exported from New Brunswick to markets throughout the world. Up until the early 1960s, commodities like grindstone, building stone, gypsum, and limestone served as the foundation of the province's non-fuel mining industry. The importance and high level of activity surrounding industrial rock and mineral development in New Brunswick is reflected in a multimillion dollar industry generating substantial revenue and providing a valuable service to its people. New Brunswick's varied geology is reflected not only by the diversity of industrial rock and mineral resources presently under development but also in several promising exploration and potential development opportunities. The province also hosts several industrial rock and mineral processing facilities, each with established technologies ensuring high-quality products and each with sufficient flexibility to supply customized products for various specialized niche markets. With the imminent availability of natural gas to parts of the province, the prospects for additional value-added processing and re-examination of known, yet presently undeveloped deposits, appear excellent. These variables coupled with the province's advantageous geographical location, highlighting tidewater access to global markets and within one day's trucking distance to a regional market of several million people, guarantee prompt delivery of high-quality products at competitive prices.

Jan 1, 2001

By Andrea Pedroza da Rocha Santos

Neste trabalho, amostras de aço Lean Duplex UNS S32304 foram submetidas à temperatura de 800°C em um forno acoplado a um difratômetro de raios-x durante intervalos de tempo de 30, 60 e 90 minutos. Com o objetivo de analisar em tempo real a transformação das fases constituintes, foram realizadas várias varreduras insitu durante os diferentes tempos de permanência em 800°C deste material. Assim, observou-se a formação da fase sigma neste aço, tanto nos contornos de grão da ferrita como nas interfaces ferrita/austenita. Os valores de fase sigma obtidos para cada tempo de exposição foram calculados através do método de Rietveld sobre cada difratograma obtido e variaram de 11% a 17%. Notou-se que a fase sigma exibiu crescimento contínuo até 60 minutos e variação após este período. Todavia, observou-se que a formação de fase sigma a 800°C ocorre de forma significativa neste material após 30 minutos de aquecimento, o que pode comprometer as propriedades do mesmo.

Aug 16, 2017

By L. Veleva, Garcia. A., G. Perez

Aluminum is a metal used for the transmission of electricity of high voltage, in the construction industry and other areas. In atmospheric conditions aluminum forms an oxide layer (Alz03'H20) as a result of its corrosion, entering the passive state. The oxide layer can be destroyed by the presence of ions (Cr, SOx-n) developing localized (non uniform) corrosion attack by pitting, difficult for evaluation. The concepts of fractals and self-similarity were used in this study for the characterization of the development of localized corrosion. Images obtained with a scanning electron microscope (SEM) of samples of electrolytic aluminum wire that have been exposed during one year in ruralurban and marine-coastal environments of the humid tropical climate of Mexico, have been processed. The development of pitting has been studied as a function of time, making a statistics of the frequency of appearance of pits versus the area occupied by them. The data show that the distribution of the pits follows a power law. Therefore, the concept of self-similarity can be applied for the study of the phenomenon of localized corrosion, describing their development with time.

Jan 1, 2006

By Matheus Sexto Alexandre Pereira

Controle e centralização de informações referentes ao processo industrial são imprescindíveis e considerando-se que na cadeia de suprimento o maior valor agregado costuma estar na produção, faz todo sentido investir em sistemas que possibilitem a otimização do fluxo, controle e qualidade do processo. O novo Sistema de Controle de Panelas (SIPAN) implantado na CSN permitiu monitorar em tempo real todo o ciclo operacional utilizando novas tecnologias de desenvolvimento de software web, além de melhorar o gerenciamento, comunicação com outros sistemas e rastreabilidade de todo o processo. O sistema implementado conseguiu melhorar a qualidade de informação para a equipe tornando mais rápida e assertiva a tomada de decisão.

Jul 30, 2018

By T. Johnson, K. Lambrych, D. Kelley

Materials for construction of equipment used in hydrometallurgical plants are selected based on a combination of their ability to perform as required in aggressive process environments as well as their cost. As a material of construction, fiber reinforced plastic (FRP) has been shown to provide equal if not improved durability relative to alternative materials such as corrosion resistant alloys at a considerably lower cost. This is particularly true in the case of equipment used in acid leaching processes for copper, cobalt, nickel and rare earth elements. The selection and extensive use of FRP over alloys in new hydromet plant construction in North and South America illustrates this advantage of FRP effectively. This paper will compare corrosion performance and cost of plant equipment fabricated with stainless steel alloys and FRP made with Epoxy Vinyl Ester thermoset resins. Real world case histories for FRP piping, storage tanks, extraction vessels, and electrowinning cells combined with laboratory based corrosion studies will be reviewed to demonstrate how FRP materials are selected for hydrometallurgical equipment.

Jan 1, 2015

By Harold J. Schock

The cases of no auxiliary ventilation and ventilation with tubing were mathematically modeled, using a turbulent dispersion model. The scooptram that is used to load is modeled as a variable-speed, variable-strength source of pollutants moving in and out of the dead-ended drift. Model predictions are compared to experimental measurements. A parametric analysis was performed to determine the effect of exhaust pipe location and time spent out of the drift, as well as to determine if a relationship existed between CO2 and NO levels. It was concluded from this analysis that when modeling a load-haul-dump cycle, it is necessary to use a model that has the capability of predicting changes in source strength as well as source location. It was also determined that four relevant factors include effective heading height, apparent longitudinal diffusion coefficient, transverse concentration gradient at the face, and average dispersion width of the exhaust jet. As these factors change with heading geometry and ventilation configuration, they were determined experimentally, Carbon dioxide was used as a tracer to calibrate the model; since, knowing the fuel flow rate, it is possible to calculate CO2 production. The above four factors in the computer model were calculated using a regression analysis, comparing predicted local concentrations to measured local concentrations. The model was then verified after this calibration process using additional experimental results. With the calibrated model, it is possible to predict pollutant concentrations at any location in the heading using an engine map and the previously calculated flow field. A parametric analysis shows that the exhaust pipe location can have a significant impact on operator exposure to exhaust gases. It was also shown that NO concentration varies directly with C02 levels. Predictions using the dynamic model are contrasted with constant source strength (pollutant flow rate) results. An analysis of these predictions for computing time-weighted average NO shows the dynamic model predictions of operator exposure to this pollutant to be less than one-half of the value predicted using a constant source model.

Jan 1, 1981

By Nawal Kishore, Nilesh Pratap Singh, Amit Kumar Verma, Vikram Seervi

In India, demand for coal exceeds its countrywide supply, despite its natural abundance, due to failure to achieve high production targets, especially in opencast mines, which are responsible for 94.98% of total raw coal production within the country. Employment of technological solutions, such as surface miners, is key to achieving higher coal production and productivity in an eco-friendly manner, especially in the populated areas adjacent to the mining zone and, hence, require restricted blasting operations. It eliminates blast hole drilling, blasting, and primary crushing units, thus reducing related environmental hazards like ground vibration and fly rocks. This paper encompasses the applicability, advantages, constructional features, and performance assessment models for each working mode of a surface miner. The current paper discusses the correlation between coal production and key productivity indicators, namely, machine shift-time, pick, and diesel consumption of surface miner in three different geo-mining conditions. Furthermore, relationships between machine shift-time, pick, and diesel consumption of surface miner and coal production were evaluated through bivariate regression analyses along with their coefficient of determination. These key productivity indicators of surface miner follow polynomial relationships with coal production on a daily and monthly basis, having Pearson correlation values from 0.774 to 0.907 and coefficient of determination, from 0.664 to 0.909 in opencast coal mines.

Jan 20, 2023

By Ernest E. Thurlow

The Geology Division of Northern Pacific Railway Company has adapted to its exploration efforts field procedures for geochemical sampling and semi-quantitative analysis which have been developed through research by the U. S. Geological Survey. The sampling is done in conjunction with reconnaissance geologic mapping on aerial photographs or during field checking of maps which have been prepared largely by photogeologic interpretation.. Stream sediment or soil samples are taken and readily soluble combined heavy metals are extracted with ammonium citrate followed by colorimetric titration with dithizone at the sample site. The effectiveness of this approach has been demonstrated both in positive and negative results, thereby assisting in the elimination of large areas of land from further immediate attention and in providing targets for followup exploration. An occasional sample is submitted for spectrographic analysis as a check on the possible presence of other elements of economic significance. Field laboratory procedures are also being implemented for determining molybdenum, mercury, and other metals which may be valuable in themselves or useful as pathfinder elements in outlining mineralized areas. A lead-zinc occurrence in Oregon and a copper deposit in Montana were readily detected and outlined by stream sediment and soil sampling and a heavy metal anomaly that lacks obvious interpretation has been found in northwestern Montana. Detailed mapping and additional sampling are followed by other exploration techniques if warranted.

Jan 1, 1964

By Z. Jing, C. Jun

High-purity Bi2O3 was prepared via extraction-preparation stripping method use BiCl3 leaching solution. Parameters such as oxalic acid concentration, phase ration, aging duration, feeding duration, were examined for their effect on the size and morphology of precipitate. The precipitate was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), particle size analysis, differential scanning calorimetry and thermal gravity analysis (DSC-TGA) and infrared spectroscopy analysis (FT-IR). Bi2O3 was characterized by elements analysis, particle size analysis and scanning electron microscopy (SEM). Bi2O3 product of 680 nm was obtained using 15 g/L oxalic acid, 1/1 phase ration, 0 min aging duration, 0 min feeding duration and calcinating at 500 °C for 2 h.

Mar 1, 2018

By A. Anttila

The grinding mill is probably the most common unit operation used in mineral processing. There is, however, much which can still be done in the way of optimization. This paper discusses the results of a well controlled pilot scale test in which the performance of a tumbling mill with a conventional rubber lining equipped with lifter bars is compared to that with a smooth rubber lining of the magnetic type. The results indicate that the smooth lining is about 14 percent more effective with respect to energy consumption. By optimizing the size of the grinding media, the mill capacity can be increased in many grinding operations. In this specific case the -20 mm ball charge required 26 percent less grinding energy than one with a -30 mm ball charge. The energy savings can. in most cases, be converted to increased capacity. The wear of the grinding media is difficult to assess over a short period test but the results suggest it is somewhat less when a smooth lining is used. The wear of the linings has not been included in this study but it is generally accepted that the use of the magnetic lining reduces the lining costs dramatically. Computer simulation using the Millsoft code, developed by Mishra e.a. confirms and explains the increased effectiveness of comminution when smooth lining and smaller grinding balls are used.

Jan 1, 1998

By D. J. Robertson

"THE copper smelting operation of the Hudson Bay Mining and Smelting Company, Limited, at Flin Flon, Manitoba, generates a gas flow of 350,000 c.f.m. at n.t.p. This gas stream passes to atmosphere through a 20-foot diameter by 250-foot brick stack, carrying with it an appreciable dust burden in the form of metallic oxide fumes. The flow constituents during the period 1952 and 1953 and •before gas filtration was included in the treatment scheme are shown in Table I. This paper describes the gas filtration treatment which was installed in 1957, using glass cloth media to recover this dust burden, and discusses the associated problem as its treatment for recovery of zinc and cadmium.The metallurgical details associated with the problem are illustrated by a description of the material flow sequence of the Company's hydrometallurgical zinc plant and copper smelter. In this ore processing complex, the zinc plant and copper smelter form an integrated unit within which intermediate zincrich products of each operation enter the treatment circuit of the other."

Jan 1, 1960

By H. O. Hoffman, C. D. Demond

There are two methods of determining the fusibility or refractoriness of fire-clays, the theoretical and the experimental. In the former, conclusions are drawn from the chemical composition; in the latter, from the changes which the clay undergoes when subjeoted to intense heat. It is well to use both methods, beginning with the actual heat-test and explaining the results obtained from this by the help of the chemical analysis. In discussing the subject, however, it is better to reverse this order. I. The Theoretical Method.* Leaving out the hygroscopic and combined waters and any organic matter, as not directly affecting the fire-resisting property, the refractory constituents of fire-clay are alumina and silica, and the fluxing constituents magnesia, lime, soda, potash and ferric oxide. According to Bischof,† alumina is the least fusible component, and silica follows close upon it. If, however, a mixture of the two be heated, it will be found that its melting-point is much lower than that of alumina, as a silicate will then have been formed. The way in which silica affects the refractoriness of alumina has been strikingly presented by Seger 1 in a diagram reproduced in Fig. 1. The abscissæ represent the melting-points of Seger cones Nos. 26 to 36 (see p. 55); the ordinates, the relative amounts of alumina and

Jan 1, 1895