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By Mazin Adnan

The 80m high dam at the Peribonka river in the Canadian province of Quebec was designed for the generation of 385 MW of hydro electrical power (Fig.1). The complex ground conditions required the employment of a variety of geotechnical construction methods stretched to limits never experienced before. Innovative grouting and trenching techniques were used for the construction of a plastic concrete cut-off wall down to a depth of about 116m, to cut hydraulic seepage through alluvial deposits forming the dam foundation. The bedrock where the cut-off wall is embedded forms a glacial gully with steeply sloped flanks, which created further challenging conditions. [ ]

Jan 1, 2008

By Wilfrid Comeau

The RICHTER scale is used in classifying earthquake severity. It is an energy scale giving the estimated energy liberated at the source of the earthquake. Earthquake damage on the earth’s surface, for example at the epicenter - spot on the earth’s surface directly above the earthquake, for a given RICHTER number can vary. This depends on the depth of the earthquake focus. Deeper earthquakes will generally cause a lower level of damage at the epicenter but the damage will be spread over a greater area. As mentioned by Randy Wheeler on Blastserve, each successive RICHTER number represents about a 30-fold increase in energy. This scale is open at both ends with “0” RICHTER equal to about 104 Joules. The lowest level detected by sensitive instruments is about 2 on the RICHTER scale or about 107 Joules. The highest-level earthquake detected at 8.9 RICHTER represents a release of about 3 x 101 7 Joules.

Jan 1, 2003

By Dennis N. Poffenroth

One concern of the Mine Safety and Health Administration is the structural integrity of steel wire ropes used on mine personnel hoists and elevators. Failure of such ropes has resulted in loss of life and property. Although thorough and regular visual examinations are performed, hoist ropes may still fail from undetected internal wear, corrosion, and broken wires. To complement visual examinations, nondestructive rope inspection techniques have been developed to determine deterioration and removal criteria. The techniques use electromagnetic and permanent-magnet test instruments designed by a Canadian firm. This paper describes the operating principles, field and laboratory testing of these nondestructive testing instruments, and discusses the feasibility of using this type of testing as a supplement to visual examination and destructive tests.

Jan 1, 1983

By John Frostiak, Lloyd Buckingham, Kenneth G. Thomas, Luis Wilson

"The El Indio roasting facility associated with El Indio Mine in Central Chile has operated since 1981. It is a facility developed to remove arsenic and antimony from gold bearing enargite/pyrite flotation concentrates.The three installed roasters are Nichols Herreschoff units each with 14 hearths and measuring 4.85 metres diameter. Hearths are rabbled by central shaft driven rabble arms. Product is progressively heated to 750°C under neutral to reducing atmospheric conditions to drive off labile sulphur, arsenic and antimony.Ancillary equipment includes skip hoist feed arrangements, water cooled screw conveyors for transporting and cooling calcine, gas cyclones, post combustion chambers, heat exchangers, electrostatic precipitators, bag houses, gas scrubbers and packaging facilities .Operating practices, history, mineralogy and results are reviewed. The improvements to arsenic and antimony extraction, ambiental conditions and environmental achievements are discussed.INTRODUCTIONHistoryThe El Indio property lies in the El Indio belt, a copper, gold and silver area approximately 175 km long by 10 km wide. The property is located in the Andes Mountains of the central part of Chile at latitude 30"" South and 160 km from the sea-side city of La Serena. Plant location is at 3850 meters above sea level.The property currently consists of two underground mines feeding the El Indio plant and an open pit feeding the newer Tambo leach plant. The property has been controlled by a succession of owners (St. Joe Minerals, Fluor, Bond Gold International and Lac Minerals Ltd.) before acquisition by Barrick Gold Corporation in 1994."

Jan 1, 1999

By K Gordon

A methodology for assessment and remediation of acid mine drainage (AMD) developed at the Sullivan Mine in the West Coast Region has been applied to the closed Blackball Mine, Blackball, West Coast Region. AMD from the Blackball Mine has low pH, high acidity, and elevated levels of iron, aluminium, manganese, nickel, zinc and arsenic. The AMD flows at a variable rate (36 - 101 L/s) into adjacent Ford Creek, causing an increase in acidity and trace element concentrations in the creek. To test the effectiveness of treatment with a simple limestone-based treatment system, a column leaching experiment was conducted over a nine day period. The results show effective removal of acidity, reduction in the concentrations of iron, aluminium, manganese and zinc, and production of alkalinity. To determine if this treatment method reduces the toxicity of the AMD to aquatic invertebrates, a 96 hour ecotoxicity experiment was conducted. The results show a significant decrease in mortality in the treated AMD compared to untreated. The column experiment, in conjunction with the ecotoxicity work, suggest that a passive treatment system consisting of a limestone leaching bed and an open limestone channel may be sufficient to treat the AMD from the Blackball Mine. Further work, such as large-scale treatment trials, is recommended.

Jan 1, 2004

By Ray. K. Filip

The concept of installing a steel sheet pile retaining wall into the ground by "pressing" has resulted in the development of various equipment solutions over the last thirty years e.g. Taylor Woodrow ?Pile Master', Giken 'Silent Piler" & Tosa 'Still Worker?. Dawson Construction Plant Ltd (DCP), have recently advanced the pile pressing concept with the introduction of their 'Push-Pull' system. This advancement offers significant improvements in the quality of installation compared with traditional pressing solutions but also greater versatility, higher productivity and, most importantly, generates new opportunities through a wider range of applications for "silent piling'. This paper will focus primarily on the use of the Push-Pull concept in the construction of a unique "integral" bridge in Milton Keynes, England. Finally, the paper touches on the development of quiet, vibration-less pile extraction equipment, which allows steel to be considered the foundation material of choice for truly sustainable construction. It is no longer acceptable to leave unwanted piles in the ground.

Jan 1, 2006

By Hyung Jeek Kim, Jongmin Joo, Jonguk Kim, Jai-Woon Moon, Kyeong-Yong Lee

"Co-rich ferromanganese crusts (Fe-Mn crusts) distributed on seamounts in the western Pacific are potential economic resources for cobalt, nickel, platinum, and other rare metals in the future. Evaluation and selection of a mining site can be established based on abundance and grade of Fe-Mn crusts in the site as well as topography that should be smooth enough for mining operations. Therefore, acquisition of shipboard echo-sounding and acoustic backscatter data are prerequisite to the selection of potential mine sites in addition to visual and sampling operations. Acoustic backscatter data can be used to locate crust-covered areas on a regional scale with the understanding of acoustic properties of crust through its correlation with visual and sampling data.During an expedition that took place from January to March 2014, KIOST collected geophysical and geologic data to assess the resource potential for Fe-Mn crusts on three seamounts (guyots) in the Western Pacific. In OSM11, one of the three surveyed seamounts, three camera tows were performed to observe the distribution of Fe-Mn crusts on the summit and slopes of the seamount. Although sediments of various thicknesses generally cover most of summit region of OSM11, several regions with high backscatter signals occur on the periphery of the summit. The occurrence of Fe-Mn crusts, observed during the camera tows, on those high backscattered regions suggests that the backscatter signals of shipboard multi-beam sonar can reflect changes in the geology of the seafloor from sediment layer to Fe-Mn crust deposits. The Fe-Mn crust deposited around the summit region is worthy of notice because of its topographic characteristics, including shallow depth, flat or gentle inclined surface, and smooth relief, which are more suitable for mining operation compared to the flanks of seamount."

Sep 1, 2014

By P. Hajiani

"It has been shown that the economics of the hydrometallurgy of a rare earth process depend upon the amount of acid needed to extract the metal per unit mass of the ore. In this paper, we show how to save a significant amount of acid treating a low grade ferrocarbonatite and extracting +99% constituent REEs. In order to save the acid, the alkali earth metals, originated from gangue minerals were removed prior to REE leaching. Moreover, the operating conditions of leaching reactor are optimized to leave iron behind and to leach REE selectively and effectively. Consequently, the hydrochloric acid consumption per ton of ore drops significantly compared to other processes.INTRODUCTIONThe viability of an extractive metallurgy process of rare earth elements (REEs) to produce an intermediate mixed concentrate depends upon a low-cost simple flowsheet (Bogner, 2014). It has been known that regardless of the mineral, the acid consumption is intimately associated with the operational cost (OPEX) of any REE project, particularly when the initial REE grade is low. Besides acid, the other reagents consumed in the process impact the OPEX. This makes minimizing acid consumption in an REE method a critical priority. The acid consumption in different projects has been reported to be equivalent of 100 kg to 1000 kg HCl (100%) per tonne of ore (Average: 500 kg/t HCl 100%) (Bogner, 2014). This value is strongly correlated with the grade of REE in the ore and therefore in the pre-concentrate.Previously, it has been stated that the Montviel flotation concentrate requires about 300 kg HCl (100%)/t ore to attain +99% REE recoveries using direct leaching (Yu, Verbaan, Pearse and Britt 2013). Hence, for an ore feed rate of 2500 t/d ROM, a large acid production plant (744 t/d HCl 100%) would be required for acid leaching of such concentrate. The equivalent Chlor-alkali plant is estimated to cost M$ 150 (CAPEX) and may require 100 MW power. Therefore, there is a necessity to improve the extractive hydrometallurgy and to reduce the acid consumption significantly."

Jan 1, 2016

By Rony Yupanqui C

El presente trabajo señala el proyecto de remediación de los relaves mineros realizado en la relavera Ticapampa, ubicado en el Distrito de Ticapampa – Huaráz, región Ancash, con el objetivo de remediar los relaves de TICAPAMPA depositados por más de 30 años y que contaminan al río Santa, fuente principal de irrigación del Valle del Callejón de Huaylas. El proyecto comprende la extracción de contaminantes del pasivo ambiental de Ticapampa a través de la flotación de los sulfuros de fierro, y la obtención de un material inerte (con bajo contenido de sulfuros contaminantes) para la fabricación de productos cerámicos por medio de resinas recientemente desarrolladas.

Sep 12, 2011

By I. A. Kunasz

This paper is not intended to review and re-state general information on lithium, but rather to analyze the paradigm that has caused such a rapid rise in lithium production and the development of new lithium producing centers. Details on pegmatites, brines, concentrate and chemicals are amply covered in a number of publications ? SME?s Industrial Minerals and Rocks, Industrial Minerals, Roskill and a host of other publications. There is no question that the latest interest in lithium has been driven by the potential development of the electric car. This stimulus prompts one to recall two symposia: 1. ?Lithium Resources and Requirements be the year 2000?, organized in 1976 by the U.S.G.S. in Denver (1) and the sequel 2. ?Lithium ? Needs and Resources? at Corning, N.Y. (2).

Jan 1, 2011

By R. G. Vardiman, M. R. Achter

Observations of dislocation structure in niobium are presented using two techniques. Triangular pits developed by electroetching are confined to orientations in the stereographic triangle between the (111) pole and planes of the (1ll) zone and require the presence of carbon. Some unusual electroetching phenomena at other orientations are noted. A chemical etch of dislocations decorated by the addition of carbon to 50 ppm reveals the complete dislocation line structure in a surface layer up to 30 p deep, with a resolution of less than 1 p. This effect is independent of surface orientation. The structure of subboundary nets may be resolved for misorientations up to about 1'. Dislocation structures found in strain anneal grown crystals, such as helices, prismatic loops, and high-density areas, are observed. The measurement of dislocation density is discussed and values obtained in different ways are compared. IN the course of some work on the response of refractory metals to thermal-mechanical treatments, it was desired to examine the defect structure of relatively low dislocation density crystals of niobium in bulk form. Surface and bulk methods for the observation of dislocations have been reviewed by ~melinckx,' and include etch pitting, decoration, and various X-ray techniques. The dislocation line structure has been developed by decoration in a few metals, although observations were limited to certain orientations, or by the coarseness and nonselectivity of the precipitate. The most commonly used technique is etch pitting. In niobium, etch pits have been developed chemically'0," in material of high impurity content and electrolyti-cally'' in relatively pure material. In this paper, etch pits developed electrolytically, and the dislocation line structure of a surface layer developed by decoration and chemical etching, are examined, and observations are presented from both techniques. EXPERIMENTAL METHODS Our starting material was electron-beam-melted niobium, swaged to 4 or -in.-diam rod. Chemical analysis is given in Table I. Single crystals were grown by a strain anneal technique using 1 to 2.5 pct of strain and growth temperatures of 1700" to 2300"~.'~ Some crystals grown by zone melting were also examined. The desired surface orientation was exposed either by spark machining or by sectioning with a cut-off wheel and prepared for etching by electro-polishing.

Jan 1, 1969

By John D. Warne

"INTRODUCTION Initiated as a part of the Bureau of Mines program for development of strategic minerals for national defense, Investigation of the fluorspar deposits of the Northgate area was begun in June 1944 and completed in March l946. Mining Operations were active in the district during most of the period of investigation.The Fluorspar, Fluorine, and Camp Creek mines develop the two more promising vein systems known in the area, the Fluorspar group of claims covering one vein system and the Fluorine and Camp Creek groups the other. Figure 1 shows the location of the properties. The Fluorspar and Fluorine properties were operated (except during the winter months) by the Western Fluorspar Corp. The Camp Creek mine was operated during 1943 and 1944 by Kramer Mines, Inc.The properties were examined April 20 and again November 4 to 12, 1943, by C. R. Wilfley, a Bureau of Mines engineer, who recommended work to determine ore reserves and to serve as a guide for development. Investigations by the Bureau of Mines covered all three properties."

Aug 1, 1947

By McKinnon R. L

Laboratory and field work on the use of wetting agents for suppression of colliery dust is described. Although the results were inconclusive they were not discouraging and further investigation is required. The use of certain wetting agents may constitute a healthhazard.INTRODUCTIONCoal dust presents explosion and health hazards to the coal mining industry. The problem of dust suppression is particularly acute where water alone is unsatisfactory for this purpose. The addition of a surface active agent (wetting agent) to the water should enable the dust particles to be more easily wetted and thus more easily prevented from entering and spreading through the mine atmosphere.Investigations into this effect carried out at The University of Sydney mainly under research grants from The Joint Coal Board (Dawson and Hargraves, 1955; Charlton and Curnow, 1957) are summarized, and information on the possible harmful effects of certain wetting agents is given.Twelve local manufacturers and five importers supplied 52 wetting agents in liquid, solid, powder, and paste form.The active material content varied from approximately 10 per cent to 100 per cent and the cost per pound from 8d. to 14/3.LABORATORY TESTINGPossible test methodsThree methods of laboratory testing were considered.1. The standard method for comparing wetting agents is the Draves test, used in the textile industry on cotton...

Jan 1, 1961

A simple and cost effective technique to increase fragmentation and burden velocities without making major modification to the overall blast design is with ALTERNATE VELOCITY LOADING OR BOOSTERING OF ANFO. The technique requires the placement of a cartridge or slug of explosive, having higher density and detonation velocity than ANFO, every few feet in an ANFO column. The greater the difference in density and detonation velocity of the Alternate Velocity Load to ANFO, the more pronounced are the results. Emulsions were selected as the Alternate Velocity test explosives because they detonate closer to ideal conditions than most other commercial explosives.

Jan 1, 1989

By Ronald Díaz Vásquez

Cerro Corona es un yacimiento porfíritico tipo stockwork con distintas unidades geometalúrgicas y alteraciones producidas por una familia de fallas geológicas que determinaron un tipo de mineralización. A medida que la mina se va profundizando, la roca encajonante será menos alterada. Por tanto, se genera una mayor dureza del mineral, así como problemas con el menor tonelaje de procesamiento. En ese sentido, el presente texto señala una forma de optimizar el procesamiento de minerales de bajo contenido de arcillas y alta dureza, así como la disminución de la malla de voladura.

Nov 1, 2013

By D. Rahal, I. Shah, B. Hines, S. Reddick

"The development of stirred milling technology has proven to be an enabling technology in fine grained metallic deposits. The increased grinding efficiency allows for the economic size reduction required to produce saleable concentrates. This improvement has opened the door to retreatment projects such as reprocessing of historic gold mine tailings. Recently a VXP2500 stirred mill was installed at Casmyn Mining Zimbabwe Turk mine to allow the reprocessing of historic mine tailings. After commissioning, an extensive joint research project between Casmyn and FLSmidth Minerals was conducted to optimize the performance of the mill. This paper outlines the challenges encountered in the optimization program and the outcomes from the joint research project.INTRODUCTION The development of stirred mills has opened up many new opportunities to recover valuable minerals from refractory ores. Stirred mills have already been reported as an enabling technology for the processing of fine grained ores in lead/zinc applications (Pease, Young and Curry, 2005). Historically, conventional ball mills were unable to economically grind material fine enough to produce the required recovery or concentrate grade. This often resulted in the loss of valuable materials to the final plant tailings. The advent of stirred milling has now provided an opportunity which has both economic and environmental benefits, the reprocessing of historic mine tailings. Many tailings stockpiles now contain economic concentrations of gold because of the ability of stirred mills to efficiently and economically grind the tailings to liberation sizes. The primary advantage of reprocessing historic tailings is very low cost processing. Recovering the tailings is usually as simple as pumping the material into the reprocessing circuit. The disadvantage of reprocessing tailings is the low feed grade and greater difficulty in recovery valuable minerals at the same size distribution. The material has already been previously processed so fresh surface area or an increase in metal exposure is required. These are both provided by regrinding the tailings material."

Jan 1, 2014

By Shahriar Vandani, Andy Herlache, Andrew Bro, Wei-Yu Chen

"The Presidio Parkway Project will reconstruct approximately 1.6 miles (2.6 km) of highway, including seven new bridges, three new cut-and-cover tunnels, and a new undercrossing connecting the Golden Gate Bridge to the City of San Francisco, California. The project site is approximately 5.6 miles (9 km) from the San Andreas Fault, capable of producing magnitude 8 earthquakes. Seismic hazards include strong ground shaking, soil liquefaction, ground settlement, and lateral spreading. The Main Post Tunnels (MPT) are two parallel cut-and-cover concrete tunnels approximately 1100 feet (335 m) long. The MPT site underlain by loose sandy soils susceptible to liquefaction and lateral spreading. Excessive racking and permanent displacement due to lateral spreading are identified as the main seismic vulnerabilities. Analyses showed that without ground improvement, tunnel racking of over 5 inches (13 cm) and permanent lateral tunnel displacement of up to 15 feet (4.6 m) could be anticipated. Cement Deep Soil Mixing (CDSM) is proposed to mitigate slope displacements and increase lateral stiffness of the foundation materials to reduce tunnel racking. A series of 2-D fully dynamic time domain analyses were performed to evaluate the performance of CDSM, confirm that performance criteria are met, and optimize the CDSM geometry and replacement ratio. The use of CDSM reduced the permanent tunnel displacement from over 15 feet (4.6 m) to less than 1 inch (2.5 cm). Tunnel racking was also reduced significantly. The adopted analytical approach presented herein can be considered for future tunnel design projects in seismically active areas.Introduction The Main Post Tunnels (MPT) are an integral component of the Presidio Parkway project which will replace the existing facility with a new multi-lane roadway between the Golden Gate Bridge and the City of San Francisco. The MPT are two parallel cut-and-cover concrete tunnels approximately 1100 feet (335 m) in length. As shown on Figure 1, the project site is located in a seismically active area, about 5.6 miles (9 km) east of the San Andreas Fault and 12.5 miles (20 km) west of the Hayward Fault. The San Andreas Fault can generate magnitude 8 earthquakes while the Hayward Fault is capable of producing magnitude 7.3 earthquakes. The design Peak Bedrock Acceleration (PBA) is 0.46g for the upper level design earthquake. The project alignment is shown on Figure 2."

Jan 1, 2014

By J. Wickens

This paper discusses how Bald Mountain Mine dramatically reduced mercury production by treating process solutions with a liquid reagent called UNR 811A. The reagent is marketed by Cherokee Chemical Co., Inc. A summary of the bench tests comparing several different reagents is given. The ensuing plant trial is discussed and results are presented. The plant trial treatment costs are discussed. Finally, potential cost savings are discussed.

Jan 1, 2001

By H. Sato, B. Thornton, K. Nishi, A. Usui

"Northwestern Pacific submarine seamounts are believed to be future marine mining areas of ferromanganese crusts, which contain hi-tech industrial metals, such as Co, Ni, Te, Ti, Pt, and REEs. The Takuyo No. 5 seamount is a member of the Cretaceous super-plume seamounts in the north Pacific, located within a Japanese EEZ (100 nm from the Minami- Torishima Is. or Marcus Is.), and only 300 nm away from the Japan’s Licensed area for exploration of Co-rich ferromanganese crusts under the ISA. This is an on-going program supported by independent academic communities but not a state-run program or managed by private funding.We have observed, sampled, measured, and analyzed the occurrences, distribution, physical properties, and microbiological environments at a selected flat topped seamount named Takuyo No.5 as a model area for scientific study of ferromanganese crusts within the Japanese EEZ. We then characterized crust structures, composition, age, and growth history, resulting in an understanding of the overall nature and distribution of these deposits from wide range of areas, water depths and geological environments. The study started with a ROV (Hyper-Dolphin 3K of JAMSTEC) exploration jointly with universities and national institutions (Japan Agency for Marine-Earth Science and Technology, Japan Oil, Gas, and Metal Exploration Corporation, and Geological Survey of Japan) in 2009 using marine geology vessels, remotely-operated vehicle, an oceanbottom drill machine, deep-tow TV camera, as well as conventional dredges and corers. We have been studying the topography, geology, nature of the bottom material of the seamounts using delicate sampling devices and measurement tools, and characterized the distribution patterns of the metal-rich ferromanganese deposits from chemical, mineralogical, and microbiological points of view."

Sep 1, 2014

By E. Fried

Cemented paste backfill (CPB) is an innovative tailings management method that consists in returning considerable amounts of mine tailings into the underground mine openings. The filled stopes thus participate to the ground support that allows maximizing orebody extraction and a safer environment for the mine workers. There are also significant environmental advantages of using CPB. Indeed, up to 50% of the concentrator tailings can be backfilled, leading to a smaller volume of problematic waste materials to be managed at the surface. Once the CPB is placed, or when the mine is flooded at its end-life, the backfill is subjected to underground water flows that may leach and spread the pollutants (mainly metals, sulphates, and acidity) which can contaminate the underground waters. The aim of this study is to characterize the leaching properties of CPB material and to identify the cement phases that ensure the metal fixation. A laboratory procedure was implemented consisting in the preparation of various paste backfill mixtures using sulphide-rich and sulphide-free materials, different types of binder, and mixing waters having various sulphates, copper and zinc concentrations. After 90-days curing time, the samples were submitted to column leaching tests. The CPB materials were flushed each day with 100 ml of deionised water during 100 days. The collected leachates were then analyzed for pH, Eh, electric conductivity and chemical composition. For some samples, a differential acid neutralisation test was carried out. The objective of this experiment is to dissolve selectively the hydrated phases by adding incremental acid concentrations. By analyzing punctually the equilibrated solutions, the composition of the dissolved phases and their metal content can be estimated. The leaching test results showed that the pH of the leachates remains alkaline during the test period. When the pH decreases under 10 (after 30 days), different behaviours in terms of chemical element release (especially for zinc) were observed. During the test, the oxidation of pyrite seems to slow down, probably due to passivating phenomena. Moreover, the differential acid neutralisation test results allowed a better understanding of the CPB mineralogy and the Zn-bearing cement phases. Zinc and the other metals seem to be fixed within a calcium-magnesium silicate.

May 1, 2007