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By A. Fuerst

The recent seismic events have shown that earthquakes have an immense destructive power. Chile was hit in February 2010 with a seismic intensity of 8.8 on the Richter scale, and had loss of about 700 killed persons, while Haiti was hit in January 2010 with 7.0 killing about 220?000 people. The event in Haiti showed that the seismic events can lead to a disaster if no preventive measures are taken. On the other side, the seismic event in Chile has hit a well-prepared country with moderate consequences. The earthquake with 6.6 Richter in Japan in March 2011, have further shown how severe the consequences can be if critical equipment is involved. Fortunately, the equipment in a mine has not the potential hazard as a nuclear power plant. Anyway, we are diligent and it is obvious that the seismic risk may lead to a real disaster even if the probability is small. The GMD is an important component in the grinding circuit of a mine. This paper maps out earthquake-prone areas including expected earthquake magnitude calculated according to relevant standards, focusing mainly on the building code IBC 2009. An overview is provided on how this standard is applied to mining equipment to minimize damage and aid large mills in operation to successfully withstand seismic effects. The differences in stresses and forces on the GMD and foundation are shown based on a turning and stopped mill simulation during an earthquake. The results demonstrate the need to maintain active and operating earthquake detection systems. Aside from detecting an earthquake?s magnitude, the sensor information can also be used to reduce the harmful effects that an earthquake has on mining equipment. As follows the earthquake requirements are defined. The last part of this paper explains how to fullfill these requirements.

Jan 1, 2012

By G Small, A Lazamanana, C Greet

When conducting gold leach tests on free milling gold ores which method is the best, bottle rolls or the stirred beaker test? Recently, a client requested that gold leach tests be conducted using the stirred beaker methodology. When asked why, because the laboratory was set up to conduct tests using the bottle rolls technique the reply was that the stirred beaker leach test would replicate the plant more closely. Not wishing to upset the client, the instructions were followed. However, the opportunity was taken to complete additional tests so that the two leach procedures could be compared. Further, this comparison was completed on two different gold ores as well as a number of different grinding media types.This paper provides a description of the two laboratory techniques employed, and presents the results of these parallel tests. Interestingly, the assertion that the stirred beaker methodology more closely replicated plant performance was not validated. In fact, the results obtained using this procedure were noticeably different from those observed in the plant, with lower recoveries and significantly higher cyanide consumptions. The bottle rolls test however more adequately replicated plant performance in terms of recovery and cyanide consumption. The reasons for this are discussed in the paper.CITATION:Greet, C, Lazamanana, A and Small, G, 2015. Bottle rolls versus stirred beaker leach testing – which is best?, in Proceedings MetPlant 2015, pp 188–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Jorge Castillo

This paper presents a dynamic analyses of heap leach pad stability under high phreatic levels and various levels of seismic loading. The dynamic analysis were conducted as fully non-linear two dimensional analyses with fully coupled liquefaction triggering using the Fast Lagrangian Analysis of Continua (FLAC) computer code. Also, the geotechnical parameters, appropriate earthquake record selection and modification, model calibration, numerical analyses and results are discussed.

Sep 12, 2005

By Sandeep Kumar Jeripotula, Govinda Raj Mandela, Aruna Manglapady

Dumper operators are frequently exposed to whole body vibration (WBV) in surface mines. Surface mining activities involve the amalgamation of comparatively high intensity of vibration and extended exposure durations. Efficient risk reduction mandates knowing of important phases of a task that poses a threat to health of dumper operators. So far in India very limited studies have been reported on WBV exposure with regard to surface mines. This paper evaluates WBV of dumper operators based on ISO 2631-1:1997 Standards and European Union (EU) Directive 2002 for different phases of job cycle. Six dumpers were considered for this study and the vibration measurements were made for all the four phases of the job cycle by placing the triaxial accelerometer on the operator’s seat-surface and at the seat-back, independently. The findings of the study revealed that the haulage task (loaded travel and empty travel) remains the chief contributor to vibration exposure according to seat-surface and seat-back measurements. Maximum frequency weighted root mean square (RMS) of 1.12 m/s2 and 1.09 m/s2 were reported for empty travel task for seat-surface and seat-back measurements, respectively. For seat-surface measurements based on RMS, Z axis remains as the dominant axis of vibration for all the dumpers during haulage task, whereas for seat-back measurements, the dominant axis varies between X and Y. Exposure action value (EAV) based on RMS has exceeded the threshold value of 0.5 m/s2 for all the dumpers during loaded travel and empty travel for seat-surface as well as for seat-back measurements.

By R. J. Hundermark, K. van der Merwe, L. R. Nelson

Taphole integrity is critical to all furnaces, but it is especially important in high intensity electric furnaces processing matte and metal of high superheat. Key furnace dimensions are the electrode proximity to the taphole, hearth sump below the taphole and the shape and location of the taphole in the furnace wall (e.g., circular versus rectangular furnace). In addition, electric furnace power density needs to be matched appropriately to any configuration to achieve operational reliability and furnace integrity. The role of furnace dimensioning is generically reviewed across many pyrometallurgical processes to explore potential impact on furnace taphole performance. Some empirical furnace dimensions and power density ratios of industrial furnaces are then compared to explore to what extent they may indeed influence taphole integrity.

Jan 1, 2015

By E. L. Rawlins

Systematic leakage surveys of natural-gas transmission lines not only aid in the conservation of gas, but can be made to show direct financial returns of large magnitude. 1. Such surveys reveal the actual leakage from the lines, and indicate repairs to be made in order, to eliminate unnecessary waste. 2. Tests on lines, after repairs are made, show the actual saving that has been accomplished. 3. Tests on newly constructed lines reveal the presence of leakage that should be eliminated before the lines are put into service.

Jan 1, 1926

By Nik Sokol, Mike Jaeger, Leo C. Weiman-Benitez

Silicon Valley Clean Water signed a progressive-design-build (PDB) contract with Barnard Bessac Joint Venture (BBJV) to design and construct the Gravity Pipeline tunnel in Redwood City, CA. Owner and Design-Builder teamed with designer Arup to provide a final product: 3.3 miles of 182 in. O.D. precast concrete segmentally lined tunnel with 10 ft. and 11 ft. I.D. Fiberglass Reinforced Polymer Mortar (FRPM) carrier pipe, complete with two FRPM Drop Structures. BBJV and Arup collaborated with SVCW to evaluate alternative design concepts, negotiate an agreeable price and reduce contingencies through a transparent estimating process, and deliver the project ahead of schedule.

Jun 13, 2023

By D. L. Koch, J. W. Tester, L. K. Sinclair

"In this study, hydraulic conductivity (K) geostatistics were used to predict residence time distribution of well-to-well flow. Flow profiles, fracture density measurements, and pumping tests were available from the highly fractured Florence Copper in situ leaching site. The flow profiles were used to establish the statistical distribution and spatial autocorrelation of K. Two tests were used for validation. The first test confirmed that fracture density and K are autocorrelated over similar length scales. In the second test, Monte Carlo flow simulations successfully recreated the results of pumping tests. Flow sim¬ulations were used to stochastically model well-to-well residence time distribution. RÉSUMÉ Dans cette étude, nous utilisons la géostatistique de la conductivité hydraulique (K) pour prévoir la distribution des temps de séjour (DTS) de l’écoulement entre les puits. Des profils de l’écoulement, des mesures de la densité des fractures et des essais de pompage existaient pour le site fortement fracturé de lixiviation in situ de Florence Copper. Les profils de l’écoulement ont permis d’établir la distribution statistique et l’autocorrélation spatiale de K. Deux essais ont servi à la validation ; le premier a confirmé que la densité des fractures et K sont autocorrélés sur des échelles de longueur similaires ; quant au second, des simulations d’écoulements de type Monte Carlo sont parvenues à reproduire les résultats des essais de pompage. Les simulations d’écoulement ont servi à établir un modèle stochastique de la DTS de l’écoulement entre les puits.INTRODUCTION In situ leaching is the circulation of a dilute acid or base solution in the subsurface, via a series of injection and recovery wells, to dissolve a target metal. In situ leach modelling requires forecasting the residence time distribution (RTD) of flow between wells. In fractured formations such as copper porphyry deposits, order-of-magnitude variations in hydraulic conductivity (K) can result in highly channeled flow, resulting in a heavy tailed RTD (Becker & Shapiro, 2003; Kang, Le Borgne, Dentz, Bour, & Juanes, 2015). Channeling through preferential pathways has impacted copper recovery at several past in situ leaching field tests (Cathles, Glenn, Lenzi, Nigrini, Deans, & Huff, 1978; Ahlness & Pojar, 1983; Schmidt, Earley, & Friedel, 1994; Sinclair & Thompson, 2015). The aim of this work is to combine multiple types of hydrogeological measurements to stochastically forecast the well-to-well RTD in fractured rock for the purposes of copper in situ leach modelling."

Jan 1, 2018

By J. L. CAHUTHERS

MANY different methods are used for transporting coal from the working face to the tipple. The common methods are animal haulage, locomotive haulage, conveyor systems, and combinations of these three, supplemented, at times, by the miner pushing his own car. Haulage may also be classified into gathering and main line. Gathering haulage is the collecting of loaded cars to a point whence they are hauled to the tipple. In this there is perhaps more lost-time than on the main line because there are .more units in the operation to be synchronized. Also, conditions on the gathering haul- age, such as bad track, poor timbering, insufficient motive power, etc., cause delays; usually these are corrected on the main-line haulage.

Jan 1, 1931

By V. Gaudreault

Rio Tinto Alcan (RTA) has three smelters that use the Alcoa P155 technology: two in Canada (Grande-Baie and Laterrière, Saguenay, QC) and one in the United States (Sebree, Kentucky). The oldest RTA P155 smelter was built in the 1970s (Sebree) and had an initial current intensity of 155 kA. In the 1990s, RTA installed an amperage booster in Grande-Baie smelter to increase cell productivity. Since then, RTA has continuously pushed the limit of this technology and the target amperage that was 195 kA in 2005 has been increased to 210 kA in 2010.This article describes the successful plant-scale trials to increase current intensity from 195 kA to 210 kA, and the key performance indicator results. It demonstrates RTA's technology leadership to undertake such a development with its Brownfield smelters.

Jan 1, 2011

Carbon sequestration in planted forests provides an immediately available, low cost option to address the greenhouse impacts of coal mining and coal utilisation in a carbon constrained world. In addition, planted forests also offer the opportunity to address other environmental issues, particularly salinity and loss of biodiversity. Given salinity is characteristically associated with agriculture in the 500 to 700 mm rainfall belt, then where such forests can also produce commercial timber products, they offer the additional opportunity to establish new, diversified rural employment in both timber growing and processing. In the majority of Australian catchments affected by salinity, where rainfall is generally less than the 700 mm limit to conventional forestry, and where groundwater reserves are often saline, the objective of achieving economically viable forestry production presents a significant challenge. In 1996, Saltgrow commenced a collaborative breeding program to combine the salt and stress tolerance of E camaldulensis, with the growth rate, stem form and wood properties of the commercial species, E grandis and E globules. This program aimed to produce trees with the potential for commercial rehabilitation of saline landscapes. Results covering a range of site conditions from SaltgrowÆs network of over 100 trials around Australia are presented. The opportunity for commercial plantations integrated with agriculture in low to medium rainfall areas to address salinity and sustainability will be discussed. In addition, the significant potential for partnerships between land-rich, cash-poor farmers, catchment management authorities seeking to invest in public good projects that enhance environmental sustainability, and major carbon producing industries with either mandated or voluntary requirements to curtail net emissions will also be discussed.

Jan 1, 2005

A quantitative chemical model of the rocks of the Broken Hill lode environment is presented to illustrate a stratiform orebody in a meaningful form to scientists interested in environmental control on the chemicalcomposition of sediments.Even though this study was restricted by the narrow range of rock analyses available it is obvious that significant chemical differences exist between the various rock units and also that some association of metallic sulphides with Ca, Mn, Fe, and P is indicated.Correlation of this evidence with that from other mining fields may point out more definite chemical relationships and elucidate the puzzle of the mode of formation of many stratiform orebodies.

Jan 1, 1968

By Walter Pajalich

This Bureau of Mines report is a study of the organizational framework of the ferrous scrap industry, of the products produced, and of the factors affecting the consumption of ferrous scrap by the steel industry. Consumption data from 27 major iron and steel firms in the States of Illinois, Indiana, Iowa, Michigan, Minnesota, and Wisconsin during the period between 1957 to 1962 were grouped by type of iron and steel furnace production facilities to determine consumption pattern for various grades of scrap in comparison to ingot production, hot metal consumption, and home scrap generation. Grades of scrap affected by changes in scrap consumption were determined, and the pattern that emerged was analyzed. Correlation of scrap demand and its effects on scrap prices based on price of scrap receipts of No. 1 heavy melting scrap and No. 2 bundles in the Chicago area for the years 1957 through 1962 indicated that demand trends do not always affect the price of scrap, Past and present technological advancements in steelmaking processes are discussed, and their effects on the scrap industry are analyzed.

Jan 1, 1967

By Gerardo Fuentes

The stoichiometry and kinetics of the hydrothermal reaction of enargite in copper sulphate solutions was investigated in the range 140–300 °C, and particle size under 15 and 50 μm. The stoichiometric experiment was performed at 300 °C, using one gram of sample (96% enargite, 4% tennantite) and 100 mL of copper sulphate solution (10 gpl) at 1.2 pH. Enargite reacted completely after 80 min. A solid product was obtained and characterized by XRD. The main product was chalcocite (M) and some traces of djurleite and chalcocite (Q). Tennantite did not react under these conditions. The kinetic experiments were conducted at 140 °C, 190 °C, 250 °C and 300 °C. From fitted data and Arrhenius equation the calculated activation energy (Ea) was 51 kJ/mol. According to the hydrothermal transformations studied, the reactivity of different phases found in the copper concentrates was bornite > chalcopyrite > covellite > sphalerite > pyrite > enargite > tennantite.

By Alfred Wild

The Kraftile Co. plant, Fremont, Alameda County, Calif.--the largest producer of glazed, structural wall units west of the Rocky Mountains-- maintains modern processing facilities to evaluate and blend a wide variety of clays from several sources to produce quality products. The report desribes the prospecting, exploration, and test methods used to locate raw material sources and covers processing methods, cost factors, and trends. Also, the geologic and ceramic factors are considered in a general discussion of the economics, potentials, and requirements of clays as raw materials for ceramic tile manufacturing.

Jan 1, 1963

By J. Baird

The Sappington Bridge, a steel arch span bridge constructed in 1904 over the Meramec River, was demolished due to its advanced state of deterioration. The demolition was a project to benefit Crawford County, Missouri, the U.S. Army, the Missouri Department of Transportation, and the University of Missouri – Rolla (UMR) was conducted jointly by the UMR Rock Mechanics and Explosives Research Center (RMERC) and the UMR Center for Infrastructure Engineering Studies (CIES). By arrangement with Crawford County, a 55-foot span of the old bridge was brought to the University Structures Laboratory in Rolla, while the longer, 200-foot span of the bridge was demolished using preburning and explosives. Originally, the longer span was to be blown up by C Company of the 5th Engineer Battalion (from Ft. Leonard Wood, Missouri) under the supervision of personnel from UMR. Unfortunately, permission for the operation from the Department of the Army could not be obtained in time to meet permitting requirements for the demolition. Therefore, a commercial demolition contractor was employed to perform the demolition, and to remove the scrap.

Jan 1, 2003

Bacterial Leaching of Complex Polymetallic Sulfide Ore The work described here concerned the study on bacterial leaching of complex sulfide minerals and polymetallic ores operated in shaken flasks and small-scale columns. The bioleaching of jamesonite was not accessible. The iron extraction in pyrrhotite leaching reached 98.2 per cent after 23 days. After 26 days, the zinc extraction of marmatite reached 92.3 per cent while the iron extraction only reached 13.6 per cent. The pulp density had effect on the metal extraction of pyrrhppite and marmatite. For complex polymetallic sulfide ores, after 10 days in shaken flasks, 97.1 per cent zinc extraction was achieved. While after 60 days in small-scale column, the zinc extraction only proceeded to 7.8 per cent; By SEM and EDXA of experimental samples and their leaching residuum, the bioleaching mechanism was discussed.

Sep 13, 2010

By John D. Spencer

Clean energy production from coal, oil, and gas, and the development of these and other energy sources continued to be a major objective of the energy research program of the Bureau of Mines.3 In 1971 increased emphasis was placed on the production of fluid fuels and chemicals from coal. Advances were achieved in the development of the Synthane and Hydrane gasification processes for producing pipeline gas from coal (page 31), and progress was made in research on solid wastes utilization (page 2), and on liquid fuels production from coal (page 37); Coal mine safety, solid waste disposal and utilization, coal preparation and transport, and fundamental research on coal and related products also continued to be the subject of extensive research. Improved methods for extracting petroleum and natural gas without surface and subsurface pollution featured research on these vital fuel and energy sources. This research was highlighted by studies of the fracturing systems of reservoir rocks, including subsurface fracture mapping and new fracturing techniques to achieve optimum production of oil and gas (page 52). Of equal importance were projects on oil recovery by water or gas flooding (page 52), by steam injection (page 57), on the identification of oil spills (page 63), and on means to reduce vehicular exhaust emissions (page 66).

Jan 1, 1972

By Thomas C. Atchison

The purpose of this Bureau of Mines investigation was to measure the amplitude and shape of the strain pulse and the size of the crushed zone produced in a granite by different explosives and to determine how these quantities are related to the detonation properties of the explosives. The reflection theory of rock breakage has shown that the amplitude and shape of the strain pulse incident at a free surface determine the fragmentation and volume of rock broken. Determination of the properties of an explosive that control the characteristics of the strain pulse produced in the rock will help in evaluating explosives for use in blasting. The investigation showed the different explosives produced a twofold variation in the amplitude of the strain pulse but little variation in the shape of the pulse. The explosives also produced a twofold variation in the volume of the crushed zone, but differences among the explosives were more accurately determined by strain-amplitude measurements than by crushed-zone measurements. The peak amplitude of the strain pulse and the volume of the crushed zone correlated with the calculated detonation pressure of the explosive.

Jan 1, 1959

By N. Pajunen

The basic objectives of current EU waste policy are to prevent waste and promote re-use, recycling and recovery to reduce negative environmental impact (2008/98/EC). In this paper, we focus on drivers and barriers for sustainable development by decreasing amount of waste and increasing material efficiency. Main target is to understand what are the most efficient drivers for environmental friendly decision making for reasonable consumption and use of raw materials. Environmental control instruments usually mean those actions the regulatory authority uses to control and limit environmentally harmful behavior of companies. A major change in the environmental control system took place in the 1980s with the focus moving from specific environmental issues to the environment as a whole. The environmental control system i.e. the legal (administrative), economic and informative instruments focuses on prevention. Before and still, the legislation is one of the main drivers in improving material efficiency. In this paper, we focus on drivers and barriers for effective industrial material use, and mainly on drivers. The objective of this study is to analyze how the drivers are working and are there any possibilities to influence on those. Our aim is also to introduce few examples of the existing supply chains and the drivers for better environmental performance and material efficiency. These examples are also compared with ideal reference scenarios. Our main research question in this article is: ?Are the financial issues the most important driver for environmental friendly strategic decisions?? In addition, retell the story from another perspective: ?The most important barrier for environmental friendly innovations seem to be the investment cost, the high risk involved in committing capital to unproven technology.? Other drivers, like the corporate social responsibility, stakeholder pressure, and general public pressure, will also affect the final decision. This article is based on research projects and literature. Keywords: drivers, decision-making, environmental management, saving primary raw material, material efficiency, sustainable production, critical raw materials

Sep 1, 2012