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By Bruno Lemelin

Falconbridge Ltd Raglan Mine has been in production since 1998 and has produced annually some 900 000T of ore grading 3.1% nickel, 0.9% copper and 0.06% cobalt. The mine is located in Nunavik, Northern Quebec. The current mine life is estimated at approximately 20 years. Reserves are composed of numerous small ore bodies situated across a 65 km strike length. Planning the extraction of the ten small mineralized zones represents a great challenge to optimize. The overall objective is to maximize the company?s return on net assets. Actual planning uses computerized technology tools like Automod and Mine2-4D, and a conventional discounted cash flow method (DCF) of calculating net present value (NPV). The complex setting of Raglan could benefit from advance valuation techniques such as the real options method (RO). This paper will present the characteristics if the mines that make it a good candidate to use RO to gain further insight.

May 1, 2004

By Richard A. Bideaux

With both unit costs per meter and average depth of drilling constantly increasing, there is a strong incentive to maximize the information acquired from drill holes, and then to make this information accessible to the geological staff. The larger the drilling project, the more advantageous computerization of data is over manual methods. The conversion to computer-readable form and the verification of large amounts of drill-hole data can be a substantial data processing task, but once accomplished, the benefits in increased accuracy and speed of interpretation will compensate for the time and effort spent in the work. For an exploration project progressing towards a preliminary feasibility study, about half of both the time and costs for all computer work of the entire feasibility study are devoted to drill-hole data base organization, and maintenance. Once drill-hole results are quantified and verified to be correct, they are immediately accessible and are not subject to further transcription or reinterpretation of errors. To obtain maximum benefits from computer utilization in this area, the drill-hole data base should be set up along with availability of the first data. For some companies, this may initially comprise a large number of purely speculative drill holes on a spacing of perhaps 1 or 2 km. Although few of these drill holes may encounter economic material, thought should be given, at this time, to the variables which will be logged when such material is found. In this way, it should be possible to set up a consistent format into which all future drill-hole information will readily be accommodated. This format may even be carried over into the data base requirements for an operating property.

Jan 1, 1979

By William K. Tolley

The U.S. Bureau of Mines (USBM) is investigating hydrometallurgical processing techniques to recycle metals from semiconductors and other advanced materials. Cadmium and tellurium were recovered from mixed CdTe/CdS scrap produced in the manufacture of thin-film photovoltaic devices. Cadmium and tellurium dissolution was achieved using hydrogen peroxide in dilute sulfuric acid. Leaching the scrap in 2.2 N H2SO4 yielded 99% Cd extraction and 98% Te extraction. Sulfur remained in the leach residue primarily in the elemental form. Elemental tellurium was precipitated from the leach liquor by adding Na2S2O5. Cadmium sulfate was recovered by evaporation. A preliminary process evaluation suggests that the process may have economic potential. Alternative recovery schemes are discussed.

Jan 1, 1995

By A. Sissing

Paper written on project work carried out in partial fulfilment of M.Sc. (Chemical Engineering) degree Thermophilic bioleaching, conducted at temperatures in excess of 65°C, provides considerable benefit over mesophilic bioleaching, particularly through extending the extent of leaching of base metal minerals such as chalcopyrite. Thermophilic bioleaching is facilitated through a group of micro-organisms known as the Archae, well adapted to extreme environment. In order to maximize the space time utilization of the stirred tank reactor in the thermophilic bioleaching process, it is desirable to maximize the loading of the finely divided mineral phase present while not adversely affecting the microbial performance. In this paper, the effect of the loading of the solid particulate phase on the bioleaching performance of Sulfolobus metallicus was studied in a stirred tank reactor. Emphasis was placed on the effect of the concentration of the finely divided solid phase (35 ? 75 µm). A model system comprised of 3% (w/v) pyrite in the presence of varying quantities of quartzite in the range 0 to 24% (w/v) was used to obtain the different solids concentrations. The bioleaching experiments revealed similar bioleaching performance in the presence of 3 to 18% (w/v) total solids. Above 18% (w/v) total solids (15% quartzite loading), bioleaching was impaired progressively with increasing solids concentration. At the highest solids loading studied of 27% (w/v), bioleaching was still observed. In terms of mass transfer, oxygen transfer potential was not significantly influenced in the bioleaching process over the range of solids investigated.

Jan 1, 2003

By Harry Asche

The last 12 months has seen the construction of the first Earth Pressure Balance (EPB) TBM excavated tunnel in New Zealand on the Project Hobson sewer storage tunnel for Watercare Services Limited, with the concurrent excavation of the second EPB tunnel on the Rosedale Outfall project for North Shore City Council. Together these tunnels involve a total length of 6km and follow an 8 year pause in TBM activity in Auckland. TBM performance on these two projects is thus of significant interest as there are four major tunneling projects totaling over NZ$8B being planned for Auckland, in similar ground conditions. Auckland?s bedrock is a weak sandstone/siltstone (East Coast Bays Formation), subject to infilled paleovalleys. The geology in the region has been significantly influenced by volcanic activity; 49 volcanoes are present within 20km of the city centre. The paper describes the design and construction challenges for the projects, including TBM performance, ?sticky spoil? management, and risks associated with basalt lava flows and two paleovalleys. Watercare?s Project Hobson also saw the successful implementation of a Geotechnical Baseline Report?one of the first uses of this type of document in Australasia. Rosedale Outfall is designed for high internal water pressures with varying hydraulic flows, with the risk of exfiltration explicitly addressed.

By T. Tafi

The Ute-Ulay project area is located approximately five miles west of Lake City, in Hinsdale County, Colorado. The Ute-Ulay Mine site is approximately one mile east of the project area. The elevation of the site is 9,200 feet and is adjacent to Henson Creek (Figure 1) [ ] The Ute-Ulay Mining complex is an inactive gold, silver, and zinc mining/milling operation, that operated from the 1880?s until the 1970?s, and sporadically into the late 1990?s. The mining complex comprises several levels of underground mines, a flotation mill, and an abandoned town site. Due to the narrow, steep sided canyon, milled tailings were pumped upstream one mile in a sluice box to a wider section of the canyon, and deposited into five tailings impoundments and one berm located between the impoundments. An estimated 9,000 cubic yards (yd3) of fine grained tailings were located in the impoundments adjacent to the creek. The Ute-Ulay project area consisted of the mill tailings impoundments located upstream from the historic mine.

Jan 1, 2011

By C. Dinis da Gama

Because of the growing importance of back analysis for the interpretation of rock slope failures, particularly in open pit mines, it is suggested a methodologic sequence of activities for dealing with those problems. The principal mathematical tools for the interpretation of the most common mechanisms of slope failures are reviewed, including methods of stress and strain analysis, which seem to be more powerful for parametrization studies, and for developing more realistic explanations of slope behaviour, such as the measurement of displacements. An application of those methods is described, using slope failures detected in a Brazilian uranium mine (Cercado), thus providing reliable shearing strength parameters for the rock mass discontinuites, which were used in the final pit design. The concept of using backanalysis results to supply input data for pit design was implemented by means of the excavation of an experimental trench within mine limits, where specific instruments were installed, and several slope failures were monitored and backanalysed, in order to yield information about sliding mechanisms in the future open pit.

Jan 1, 1983

By Hae-Moon Choi, Sang-Don Lee, Chang-Ha Ryu

The purpose of the study presented in this article is to establish a standard blast pattern to yield optimum blasting performance along with an attempt to reduce a difference between design and construction. A series of test blasts were carried out at two tunneling sites of Central Inland Highway crossing in Korea. Long-hole blasting was tested in rock mass whose RMR value is over 60.The blasting results were evaluated by measuring degree of fragmentation, advance rate,muckpile distribution, overbreak, etc. Based on the results of test blast, several patterns were proposed for a two-lane highway tunnel.

Jan 1, 2006

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

Jan 1, 2005

By Karen C. Armfield, Gisele R. Passalacqua, Joanna Smith

When selecting a solution for improving resiliency at facilities, such as airports, utility and transit sites, there are many options to protect structures and equipment against potential flooding. Each case involves an evaluation of the several key factors such as: design flood parameters, the geography and geological conditions below the site, the facility, and the layout of buildings and equipment to be protected. Upon reviewing these conditions and conducting a cost analysis of various options, the most suitable approach to protecting a facility can be determined. This paper will compare the conditions at various New York City sites, and give detail to the solutions utilized at these sites to improve resiliency and protect each facility. Flood wall types varied as did the strategies for raising critical equipment, to meet the Federal Emergency Management Agency (FEMA) and American Society of Civil Engineers (ASCE) 7 guidelines. Due to granular soil conditions, some sites may experience soil seepage below the flood wall resulting in the need for underground cut off systems. The authors will also present detail regarding the solutions used to control seepage. Various cut off systems will be discussed such as grouting and sheeting, explaining the factors that may impact the choice of systems. Another consideration in flood resiliency is the potential for a buoyancy condition on basement slabs when localized flood barriers are employed on first floor doors and windows. The authors will discuss the potential impacts of this condition on facilities and methods to mitigate this issue. 1. INTRODUCTION New York City is an urban coastal Metropolis with varied geology and low land areas. This includes but is not limited to sandy soils at Coney Island and the John F. Kennedy Airport. Soft marshes are found near Flushing Queens and LaGuardia Airport. Heavy rains and coastal storms caused disruption to daily life and heavily affected the economy of this vibrant City. For instance, in lower Manhattan business was interrupted in the Financial District. Power outage was widespread; commuter trains and subways were stopped and put out of service. Additionally, numerous residential homes were damaged in Coastal Neighborhoods such as the Far Rockaways and Staten Island. 1.1. Superstorm Sandy Flood Statistics On October 29, 2012 Superstorm Sandy impacted numerous facilities in the New York City Metro area. The resulting damage cost New York City more than $42 billion in repair costs. $33 billion was allocated to repair housing and infrastructure, and $9 billion was allocated to protect transit systems1. One of the major issues that impacted the city in terms of its preparedness was the high flood surge. The surge surpassed the former base flood elevation and reached as high as 13.88 feet (above mean lower low water - MLLW) in Battery Park at 9:24pm that evening. Tottenville, Staten Island experienced more damage where the water was recorded at +16 (North America Vertical Datum of 1988 - NAVD88), which is equivalent to 18.7 feet above MLLW (see Fig. 1). Not only was the surge at record levels, the waves in New York Harbor were also at record level where some buoy stations recorded waves of up to 32.5 feet. The City released “A Stronger, More Resilient New York” in June 2013, a plan laid out to rebuild communities impacted by Sandy and improve the resiliency of the infrastructure and buildings in New York City. Figures below help to illustrate the extent of the inundation relative to the projects being discussed.

Jan 1, 2018

By Murat Alkan

In this study, a self-propagating high-temperature synthesis (SHS) and following acid leaching techniques were carried out to produce boron carbide (B4C) powder. First, B2O3 was obtained through calcinations of H3BO3 at 1073 K for 2 hours. Then, the glassy B2O3 obtained was crushed and sieved. In the SHS experiments, different amounts of B2O3, Mg and C black were used. The SHS product was obtained in the form of black, spongy solid. In the leaching step, the SHS product was leached in a HCl solution to eliminate the MgO and Mg3B2O6. The effect of acid concentration on the selective leaching was studied at different concentration range, solid/liquid (S/L) ratio, and temperature. The products obtained were characterized by using X-ray diffraction, chemical analysis and SEM techniques.

Jan 1, 2009

By J. R. Thoenen

For several years the Bureau of mines has been investigating the characteristics of ground vibrations produced by quarry blasts. Considerable basic information has been obtained in the course of this study, and the results have been made known to the public through various publications listed in the accompanying bibliography The studies have been confined to obtaining fundamental knowledge of the characteristics of the vibrations themselves, because it was evident at once that he problem was extremely complicated. It was felt that any attempt to predict the effect of a ground vibration on any type of artificial structure would be useless until the complexities of building vibrations are better understood. As opportunity offered, teats wore made in various types of structures and the effects of vibrations from many different sources were measured. In one set of tests (5)4/, it was demonstrated that the behavior of a building as quite different if it was shaken by vibrations originating outside tae foundation walls than if the source of the vibrations was within the building; vibrations coming from the ground outside seemed to shake the building as a single, loosely-coupled structure, whereas mechanically induced vibrations within the house seemed to set floors and walls in motion as independent units, each of which communicated its own natural motion to the adjoining member, causing a very complicated movement that was impossible to interpret.

Jan 1, 1938

By Renaud Adams, Vladimir Salatic

"The El Mochito Mine located in Honduras, Central America, has produced lead, zinc and silver in concentrates since the 1950s. The paper discusses changes made in both lead and zinc circuits to reduce costs while maintaining production during the recent period of low metal prices.The intent of this paper is to show that sometimes thinking “outside the box” is beneficial for progress. Also, in striving for better metallurgical results we should not forget the basics of flotation. Sometimes the latest trends may not be applicable to the ore we are treating and may not meet the operating cost constraints.A major beneficial impact on El Mochito metallurgy was achieved when the overall grind was coarsened, eliminating the significant percentage of slimes. Switching from two parallel twostage grinding circuits to one circuit with three-stage series grinding has resulted in a significant reduction in power and steel consumption. With minor layout/reagent modifications, both lead and zinc circuits gained not only in retention time but as well in producing better grade products.Of course, the challenges are still there; they exist and only with the full support of operational data collection and metallurgical laboratory investigation success can come. That is why, we as professionals, can never stop in trying to make the most of what we have.INTRODUCTIONThe El Mochito Mine is owned by American Pacific Honduras S.A. de C.V. (AMPAC) a subsidiary of Breakwater Resources Ltd. Of Toronto, Canada. The mine is located in western Honduras, approximately 220 kilometers northwest of the capital city, Tegucigalpa and 90 kilometers south of the country’s second largest city, San Pedro Sula. The mine began operating in 1948 and to date has produced more than 19 million tonnes grading 240 g/t Ag, 3.5% Pb and 7.4% Zn. Production in 2005 was 700,190 tonnes grading 87 g/t Ag, 1.85% Pb and 6.61% Zn.Decreasing metal content in the ore followed by the lowest zinc price on the market in the last 15 years (see Figure 1) has reduced the cash flow and endangered to stop the operation."

Jan 1, 2007

By Don Hickey

The MTA in conjunction with LIRR, are in the process of expanding one of the largest commuter railroads in the country, with over 260,000 passengers a day. The LIRR, which provides 700 passenger trains every 24 hours, can?t continue on the present growth course as a joint tenant in Penn Station with Amtrak and NJT. For this reason, in conjunction with the fact that over 53% of LIRR?s current riders into Penn Station are ultimately bound for the East Side of Manhattan opening, have created the need for the expansion of the LIRR. The complete expansion will cost approximately 6.3 billion dollars and all of the contracts are to be completed by 2013.

By Brian Maroney

In this paper an overview of the California Department of Transportation's (CALTRANS) bridge design criteria is presented. Special emphasis is focused upon seismic design and retrofit criteria. Topics include earthquake load definitions, foundation and structure type selection, structural earthquake analysis, and structure behavioral requirements.

Jan 1, 1993

By E. G. King

As low-temperature heat-capacity and entropy data were available for only one sesquisulfide (cerium sesquisulfide), it appeared desirable to augment the information for this class of compounds by measuring the sulfides of antimony and indium. In addition a pressing need existed for data on indium sulfide to supplement vaporization studies in progress in the Department of Mineral Technology, University of California. This Bureau of Mines paper reports low-temperature heat-capacity measurements and entropy evaluations at 298.15° R. of antimony sesquisulfide of stoiehiometric composition (Sb2S3) and of indium sesquisulfide which was somewhat deficient in sulfur (In2S2.93). The data for the latter substance were adjusted to correspond to the stoichiome tric composition (In2S3 ) . Indium sesquisulfide has a lower entropy at 298.15' K, than either antimony sesquisulfide or cerium sesquisulfide, in line with the higher atomic density of the indium compound.

Jan 1, 1962

By Richard L. Fowler

An automatic steering control system was designed, installed and tested on a coal mine shuttle car. The system utilizes sensors and associated signal processing electronics developed under a previous phase of this contract. The automatic steering system performs the routine guidance functions of turning corners and straight-through tramming. The shuttle car driver retains full authority of speed, braking, load and unload functions and at any time may exercise his option with manual override or steering. Steering information is generated from signals derived from the existing Lateral Guidance sensor subsystem, and all operational features of the previously developed open-loop system are retained. Above ground system tests were conducted in a simulated mine constructed of wood panel ribs. Results were in good agreement with prior hybrid computer simulations undertaken to validate the basic control system over a broad range of conditions and to select system parameter values. The automatic steering system was successfully demonstrated in the above ground simulated mine to USBM technical representatives. Designed to meet USBM permissibility requirements, the system is ready for a Phase II underground testing program. Testing in actual underground mine environment is expected to provide additional data regarding recommended performance improvements and implementation techniques.

Jan 1, 1975

By Lyman G. J

Magnetic separator operation in the recovery of magnetite in heavy medium circuits was studied by conducting a series of tests on a full size wet drum magnetic separator.The significant operational variables were found to be feed pan clearance, squeeze pan clearance, dry magnetite feed rate and separator drum speed. With feed and squeeze pan clearances optimized for typical primary separator operation, magnetite loss and concentrate specific gravity were found to be related in a regular manner to dry magnetite feed rate at any drum speed.A two component model of magnetite loss is proposed, relating total magnetite loss to losses in the feed pan and squeeze pan zones. The experimental curves relating magnetite loss to dry magnetite feed rate at the various drum speeds are interpreted in terms of the two component model.The magnetite particle size distribution in the separator was also examined. The tailings magnetite was found to be finer than the feed magnetite only when the dry magnetite feed rate was low, or immediately following the introduction of a new charge of magnetite when the separator was fed at an intermediate dry magnetite feed rate.

Jan 1, 1983

Prefeasibility planning and cost estimation of conveyor systems has historically been undertaken by comparing fixed plant transport requirements to that of similar systems in service. This paper describes the development of a prefeasibility conveyor technical design and cost estimation application using Microsoft Excel Visual Basic for Applications (VBA) platform. The application tool known as D-Convey (Dachshund Convey) was developed with the goal enabling the end user:- to develop a technical model for conceptualised conveyor systems,- to perform economic analysis on the developed technical model, and - to conduct a comparative and risk analysis.An Excel VBA based platform was utilised to draw upon both the analytical and graphical capabilities of a spreadsheet. Some of the features of D-Convey system include a revolutionary dynamic graphical help system, known as the 'information pane' in lieu of traditional help files as well as the use of familiar graphical user interface elements such as the MS Office 2007 task ribbon. The D-Convey system incorporates material database allowing for mass handling prefeasibility estimation in other industries; it has been validated at a local quarry.

Dec 6, 2010

By J. D. Miller, C. L. Lin

In the processing industries, it is well known that particle shape is an important factor which determines the behavior of particulate systems. For example, system properties of technological significance including rheology, suspension stability, agglomeration, packing, permeability…etc, are affected by particle shape. In this regard, characterization and analysis of particle shape is essential for more detailed understanding and improved development of particulate processes. In general, it is clear that the behavior of these systems depends on the statistical characteristics of particle shape. Remarkably few techniques exist to predict the mechanical and hydrodynamic behavior of an irregularly shaped particle or a population of irregularly shaped particles for that matter. The lack of models and correlations can be attributed to the wide variety and complexity of particle shapes, the difficulty of defining shape descriptors suitable for modeling, the limitations of measuring shape, and the lack of classifying techniques to characterize particle shape. In this paper, we present information on how 3D particle shape can be measured, characterized, and analyzed using cone-beam X-ray microtomography (XMT).

Jan 1, 2005