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By L. A. Gomieroa

The Caetité-Brazil uranium facilities produce about 340 t/y of uranium from an ore averaging 0,25 U %. The process steps are ore crushing, heap leaching with sulfuric acid, U separation and purification by solvent extraction with tertiary amine followed by stripping with sodium chloride solution and precipitation as ammonium diuranate that is dryed. A change in the milling process is being evaluated to increase the production and the uranium recovery. Heap leaching will be changed to conventional tank agitated leaching of the ?590 ground ore slurry in sulfuric acid medium. The replacement of the stripping reagent is also being considered.

Aug 1, 2010

By David C. Cook

The milling complex, situated just east of the Cassiar townsite, receives raw ore from the tramline and processes it into 105,000 tons per year of milled asbestos fibre. The ore is passed through a concentrator, where a barren rock fraction is removed. The concentrated ore, representing 70% of the feed, is dried, stored and then milled into nine separate fibre classifications. The finished product is packaged into 100-lb bags and loaded into trucks in one-ton units. New air-handling facilities were added in 1977to provide additional air for environmental control.

Jan 1, 1978

By M. J. Collins

The Advocate Mines Limited asbestos property is 6 km north of Baie Ve rte on the northeast coast of Newfoundland. Mining began in the early 1960s and was concluded in 1981. The chrysotile asbestos deposit lies at the north end of the Baie Verte Lineament, the interface between a closing ocean floor and continental margin. Asbestos occurs within ultramafic rocks of abducted ophiolite massifs that were thrust westward against Fleur-de-Lys Supergroup metasediments (continental rise sediments) in the Lower to Middle Ordovician. The asbestos-bearing ultramafics belong to the Central Ultrabasic Sequence of the Advocate Complex. Serpentinized peridotite of this sequence has a 'waste cap' core that grades outward to increasingly sheared rock. Asbestos is found mainly in a northtrending, basin-shaped zone surrounding the core, specifically within fractured serpentinized peridotite that abuts the sheared rock. Asbestos appears as stockworks of chrysotile cross fibre veins and is concentrated between brown, narrow brucitic dunite dykes and sills. Shear contacts commonly surround the ultrabasic body. Cross faults and complex Jointing also exist. The Advocate Mines Limited mill produced 65,000 tonnes of Group IV fibres and 1 l , 000 tonnes of Group VJ fibres annually. The bagged product enjoyed markets worldwide.

Jan 1, 1984

By Gilles Bonin

Structures and serpentinization patterns in the Thetford Mines peridotites are important characteristics indicating the necessary geological conditions which led to the development of chrysotile orebodies in Early Ordovician limes. These structures and serpentinization patterns are reviewed in this paper using the geology of LAB Chrysotile orebodies as a model. Structural aspects include parallel and transverse faults, parallel and transverse granite slabs, and orebodies, some of which trend clearly north-westward parallel to the accretionarymovement. Serpentinization patterns in the peridotite belt, particularly in the harzburgite, include primary pervasive mass serpentinization and secondary complete serpentinization. Listwaenites layers appeared along some faults and along some granite slabs as a result of hydrothermal alteration of the serpentine, following the emplacement of the devonian plutons to the south. These plutons as we/1 as other important lineaments, align with the structural pattern of Thetford Mines ophiolites. It is believed that these plutons are part of a heavy magma tic corridor resembling the Pilote-Mont-Louis corridor in the Gaspe (Doyon and Berger, 1997), and the Buchans' structure in Newfoundland (Hutchinson, 1984), both intersecting the Brompton-Baie Verte line.

Jan 1, 2001

By Sebastian Siebert

Unmanned Aerial Vehicles (UAV) as a data acquisition platform and as a measurement instrument have become attractive for many surveying applications in civil engineering. However, their performance is not well understood for these particular applications. The specific scope of the presented work is the performance evaluation of a UAV system that was built to rapidly acquire mobile 3D mapping data for large earthmoving construction sites. Details to the components of the developed system (hardware and control software) are explained. A novel program for photogrammetric flight planning and its execution for the generation of 3D point clouds from digital mobile images is explained. A performance model for estimating the position error was developed and tested in several realistic construction environments. Results to these tests are presented as they relate in particular to large excavation and earth moving construction sites. Results and experiences with the developed UAV system are in particular useful for researchers or practitioners in need for successfully adapting UAV technology for their application(s).

Aug 1, 2013

By P. K. Kaiser, F. Amann

"Rock mass characterization for deep underground construction and mining offers many challenges. This paper first describes some of the key challenges when characterizing highly stressed brittle rocks and then offers some guidance on how to arrive at reliable rock mass strength parameters for deep mining applications. Focus is placed on characterization for rock mass strength determination. It is illustrated how the common use of currently available rock mass characterization systems tend to underestimate the strength of rock at depth. Modifications to currently adopted approaches, i.e., the use of Geological Strength Index GSI for rock mass strength determination, are presented.INTRODUCTIONFor green fields projects, the first challenge of rock mass characterization stems from a lack of access to examine the rock mass at scales larger than typical core sizes (i.e., ~63mm in diameter) until late in the mine design when the flexibility for making changes is constrained. Hence, rock mass characterization often has to rely on information derived from boreholes alone (e.g., core, logs, etc.). This challenge is lessened when mines are expanded from existing operations. A second challenge is related to changing rock mass behaviour with increasing depth and stress. At depth, the rock is highly stressed, thus closer to failure, and often highly confined which leads to a higher interlocking with elevated strength but more brittleness. The goals of rock mass characterization are to be tailored to the technical goals of an investigation. For example, for cave engineering, the workflow includes the assessment of five key engineering aspects (Brown, 2007): Caveability; fragmentation; cave performance; extraction level stability; and mine construction (rock support). Each engineering aspect has to address specific engineering questions and each design component is influenced by different rock mass behaviour aspects and thus is dominated by different rock mass properties, e.g., the vulnerability to stress fracturing (spalling), the bulking characteristics for flow control and support selection, and the confining stress impact on pillar or support design. An effective rock mass characterization program, including logging, mapping and laboratory testing, thus has to collect and interpret features that are relevant for the above listed purposes. Some of the predominant factors are: block volume of defected and non-defected rock; spalling strength; tensile strength of defects; rock mass modulus; and rock mass strength parameters for application to low and high confinement design aspects."

Jan 1, 2015

By Robert E. McIvor

"Use of the Bond Work Index to size industrial grinding equipment was widely known. Bond also described its application for measuring grinding circuit efficiency. Bond Work Index efficiency also has been used extensively by industry, but until now without concise standard methods, or a formal guideline, for doing so. The Bond Efficiency Sub-Committee of the Industrial Comminution Efficiency work group of GMSG has produced such a guideline, which is appended hereto. It covers the methods and provides examples of how to calculate the Bond Work Index Efficiency of most industrial grinding circuits. Bond Work Index testing equipment and methods are also provided.Comminution is responsible for a major portion of mineral processing plant energy consumption and operating costs. Bond Work Index efficiency provides valuable means, first, for benchmarking one’s plant performance against others in the broad industry, and hence defining the extent of the opportunity for improvement. Secondly, improvements in circuit efficiency with implemented changes can be quantified and monitored as part of continuous improvement efforts. These two important business activities are thus facilitated, and, in the absence of any other accepted method, otherwise would be lacking without the existence and application of this standard for comparison. While often loosely applied in the past by plant metallurgical staffs, the increased precision offered by this guideline provides much clearer definition of both the conceptual and statistical meaning of these measurements. Even a small improvement can be enormously financially important, but only if differentiated by measurement. This guideline was thus intended to provide industry improved means to differentiate comminution circuit efficiencies. Carbon footprint reduction is coincidental, but nevertheless can be substantial.The next steps are: (1) to establish standard reference testing materials and one or more laboratories to serve as bases for reference testing; (2) to establish the accuracy of relative circuit Work Index Efficiency determinations; and (3), to develop and provide a public data base of industrial comminution circuit Bond Work Index Efficiencies."

Jan 1, 2016

By P. E. Georghiou, S. Shafiei Zadeh, H. Hassan Nejad

Data are presented on the extractant behaviour on toxic metal removal from spent hydroprocessing catalyst, produced at the North Atlantic Refinery plant in Newfoundland and Labrador. Aliquat 336 was selected due to its potential capabilities for the separation of cobalt, molybdenum and nickel from the leachate extractant produced by aqua regia. The solvent extraction process was statistically modeled using central composite design (CCD), and the numerical optimization was conducted to achieve the optimum point for toxic metal recovery for the extractant.

Jan 1, 2014

By H. E. Wilde

"Zinc has been used for many years as a galvanic coating for the protection of steel. Electrochemical measurements show that zinc actually overprotects steel. The corrosion rate of DQSK (drawing quality semi-killed) steel in air saturated salt water was determined as a Junction of applied cathodic potential. The resulting data indicate that at a critical cathodic over potential of - O. 725 Vsce an acceptably low corrosion rate of less than 1 mpy occurs. Using the developed criterion, alloys of Zn/X and AL/X were produced and evaluated in galvanic contact with steel in a standard laboratory test. The results indicate that Zn /Mn, Zn /Co, AI/Mg/Si and AI/Mg/Ge alloys offer excellent galvanic protection along with (a) no hydrogen evolution, and (b) improved dissolution life over Zn coatings.IntroductionZinc coated (galvanized) steel has been successfully used in applications where bare (or painted non-galvanized) steel would suffer corrosive attack. In general, galvanic coupling to zinc, as either an anode or a coating, is an effective means for combatting steel corrosion. Because of this, the use of galvanized steel has increased markedly, stimulated primarily by automobile manufacurers seeking to extend the corrosion warranties on automobiles(1).Although effective, zinc coatings are not without a number of drawbacks which warrant efforts to improve them. For example, because of the widely differing electrode potentials between zinc and steel ( - 1.05 Vsce and - 0.60 Vscc, respectively, in air saturated NaCl solutions), the zinc corrodes at a rapid rate to protect the steel. This is reflected in the limited lifetimes of galvanized unpainted siding. The basic electrochemistry controlling the situation is shown in Figure 1, for a system controlled by oxygen reduction. The zinc corrodes sacrificially to protect the steel, while cathodically polarizing the steel to a potential near that of zinc's open circuit anode potential."

Jan 1, 1990

By John Keay, Douglas R. Shaw, Gregory J. Olson

"The results are presented herein of on-going laboratory investigations of heap bacterial oxidation as a pretreatment method for the recovery of sulfide-encapsulated gold from ore samples of the Rhodes Mining Lahoca deposit, located in northern Hungary. The ore contains just over 2 g Ault and as much as 6% sulfide, mostly as pyrite. Laboratory aerated column tests conducted at Colorado Minerals Research Institute (CMRI) showed that mild to moderate biooxidation of the finely crushed ore occurred rapidly in approximately three months, with cyanide gold recoveries of up to approximately 60%. The results contrast cyanide gold recoveries of less than 30% from non-pretreated ore. Mineralogical examination of biooxidized residues indicated that the mechanism of biooxidation of crushed ore was related to microorganisms following pathways along structural anomalies in the pyrite grains. Such selective biooxidation is an important result to minimize the biooxidation and aeration time and effluent neutralization costs in a commercial operation.IntroductionThis paper describes the development of a heap biooxidation process for the Lahoca gold project The Lahoca deposit is situated in northern Hungary, at the site of a former copper mining area. Lahoca is a large tonnage, relatively shallow, deposit amenable to open-pit mining Lahoca has the potential to produce I 00,000 ounces of gold annually for at least ten years at its minimum reserve base.The laboratory test work conducted initially by Rhodes Mining NL demonstrated that the Lahoca refractory ore is amenable to whole ore and concentrate oxidative pretreatment and cyanidation. Capital and operating costs, however, for such milled ore treatments were considered relatively high. Rhodes Mining subsequently evaluated heap leaching methods, particularly heap biooxidation pretreatment, as a process route that promised superior economics suitable for exploiting lower gold grade refractory ores.This paper focuses on the laboratory column (simulated-heap) biooxidation test work, particularly the proposed mechanism of selective microbial oxidation, wherein only a small amount of the sulfides are oxidized sufficient to allow commercially acceptable gold recoveries by conventional cyanide heap leaching. Selective or minimal biooxidation of sulfides is considered important to minimize biooxidation time and aeration requirements, as well as acid effluent neutralization costs."

Jan 1, 1998

By Yoginder P. Chugh

Beginning in 2010, a scientifically-founded water spray system for continuous miners (CMs) has been in development at Southern Illinois University that significantly reduces respirable dust exposure for workers in the face area (patent pending). It includes engineered sprays around the cutting drum, outer bitring sprays, chassis sprays and side cutter boom sprays. About 3.6?4.5 m behind these sprays are additional sprays that cover the area between the CM chassis and the mine roof and ribs. The innovative spray system uses approximately the same volume of water as spray systems currently used on CMs and with similar operating pressures. The innovative spray system design also takes into consideration coal dust wettability. An Illinois mine decided to implement these concepts on a CM during the rebuild stage. Dust control performance of the rebuilt CM was evaluated using gravimetric dust sampling and real-time monitoring with multiple personal dust monitors. The average results based on gravimetric sampling of about 105 cuts show about 30 and 20% reduction in dust exposure for the miner operator and the haulage unit operator, respectively. Visibility in the mining areas was also significantly improved. Since the initial demonstration, the coal company has implemented the system on all of their operating CMs.

Aug 1, 2013

By W. J. D. Stone

Discussions with people knowledgeable in the insulating material field revealed that materials on the market would be considerably improved if there was a greater meeting of certain very desirable criteria. Such criteria include: (1) the material should not burn, even at higher temperatures; (2) at an elevated temperature, the material should not give off toxic gases or produce smoke; (3) the material should have a low energy input; and (4) vermin would find the material unattractive. Theoretical discussions led to the conclusion that an insulating material made by foaming a mineral, preferably of a platy nature, with an inorganic binding system that could be converted to a rigid structure at low temperature would likely meet all the above requirements. It was also theorized that the use of microwaves in the converting stage would be beneficial in the creation of a cellular structure by aiding the foamer through creating vacules of steam. Talc was selected as readily meeting the theoretical mineral requirement and the material of Baker Talc Limited was used as the basic filler. The early results obtained led to an agreement between Americ Mines Limited and Baker Talc Limited pertaining to commercial production in a specific geographic area. It was recognized that due to the economics of shipping, the availability of the basic filler material should be geographically widely spread. Samples of materials were requested and many received from all over North America and one from Britain. Enough work has been done to show that they respond to the basic process in a similar manner as the Baker Talc material. From the data acquired, it is considered that the process is applicable for the production of loose fill insulation, moulded insulation for pipes and structural steel, ceiling tile, batts, sheet and for incorporation into other products such as various roofing board materials. Sufficient development has been done to enable a budget to be prepared for the construction and operation of a loose fill insulation plant.

Jan 1, 1979

By Virginia Lawson, Adam Price

The rougher flotation stage is used to reject liberated gangue at a coarse size. Base and precious metals due to their high specific gravity tend to recycle in the grinding circuit and report to the flotation circuit at a finer size than the gangue from which it is being separated. Generally liberation levels of greater than 50% are achieved in roughing and thus a portion of the feed can be immediately upgraded to final concentrate. The proportion increasing as the amount of liberated mineral in the feed increases. Scalping out concentrate from the rougher can reduce the size of the subsequent regrind and cleaner circuits. Examples of alternative process design for circuits demonstrates that you don’t need large volumes to effectively recover all of the minerals – you need smart flotation. Several case studies will be presented where circuits can be significantly reduced in size by designing smarter – not larger. This paper describes case studies to test the amenability of the Jameson Cell to produce final concentrate from rougher feed. Metallurgical performance and plant design implications are discussed. Froth flotation has been used extensively for mineral concentration for over 100 years. Although the flotation cell design has changed, it has generally simply increased in capacity rather than increase in efficiency. Cell capacities of over 600 m3 are now being used in rougher flotation particularly for the lower grade ores where the amount of surface area for flotation is deemed less significant than the required volume. The plant design volume in rougher flotation comes from laboratory batch flotation tests and/or pilot plants. The volume required for the plant is calculated based on the laboratory residence time multiplied by a scale- up factor. Examples of laboratory to plant scale-up design are given in Dunne et al. (2010 part 2). The factors are usually between 2 and 3. A laboratory residence time of 10 minutes would equate to a plant design residence time of 25 minutes using a 2.5 factor. The volume of the required flotation cells can then be calculated using the design tonnage and volumetric throughput. This scale-up factor takes into account the differences in performance between batch flotation efficiency and full scale plant. The differences are likely related to inefficiencies of bubble particle contact in large cells as well as froth recovery, which is essentially complete in a batch cell. Flotation cells, such as the Jameson Cells, are smarter designs that improve bubble/particle collection, bubble/pulp separation efficiency and operate with high froth recovery rather than simply getting bigger. The Jameson Cell was designed on the principal of improving the collection efficiency of fine particles by separating the contact zone from the separation zone and having the bubbles generated by the plunging jet shearing and entraining air. This means the method of bubble generation is not impacted by the wear of mechanical equipment as it the case in other flotation devices. Jameson Cells make bubbles less than 600 micron in size under most operating conditions (Ding, 2016).

Jan 1, 2019

By Asfahani. Jamal, Randa Mohamad

"Abstract - Electrical and structural characteristics of formations favorable for sulfur occurrences in northeast Syria are described using geo-electrical prospecting methods. Simple (VES) and combined (CVES) Schlumberger vertical electrical soundings and geo-electrical profiling using a Wenner configuration were applied to the Teshreen structure. Six profiles (A, B, C, D, E, and F) at the borders of anticlines, where positive and negative structures are joined and salt formations have a tendency to disappear, were studied.Secondary structures, characterized by high apparent resistivity exceeding 3000 Ohm.m were located on each profile using a Wenner profiling configuration. These secondary structures are demonstrated to be favorable for sulfur prospecting by both drilled wells and vertical electrical soundings. Traditional interpretation of the 84 VES measurments is supported by data from 14 CVES measurments. The CVES technique is a powerful tool, due to its improved resolution of the electrical boundaries.Thicknesses and resistivities of the Lower Al-Fares, Al-Garibeh, and Al-Dibbaneh formations were determined through the interpretation of VES measurments. The same VES measurments were then interpreted using the Pichgin method, whereby all the subsurface tectonic features were determined for depth penetration corresponding to AB/2 = 1000 m. The integration of the first and second VES phases creates a clear picture of the subsurface, including tectonic, geometric, and geoelectrical information. In summary, the sulfur occurrences in the research area are controlled by tectonic paths that are well defined by geo-electrical methods. These diverse geo-electrical methods could be used successfully for sulfur prospecting in similar environments."

Jan 1, 2002

By Christoph Mueller

?Globalization and the impact on mine operations? is one of the themes of the 2003 annual CIM meeting. Global mining business in practice always means to act with local base material resources in order to reach the mining company?s global business goals. On the other hand these operations are characterized by cost pressure and cycling product prices. Driven by actual prices, local product markets and local production cost, one time one mine can be most efficient while under different circumstances another mine will be the most efficient producer for the same customer [PENSWICK, 2001]. Therefor in the future the most profitable mining companies will be those who have permanent ?real-time? control on their actual production cost level. Certain approaches are under way to provide reliable modeling tools for aiding mining companies in highly complex decision finding procedures. A high potential for enhancing efficiency is the integration of all single steps of the mining working chain into a production process structure to make advantage of an optimized flow of material and information through the ?moving ore factory? [WIGDÉN, 2001]. Crucial to all these activities is the ability of getting reliable, just-in-time information from the entire mining production chain. As modern mining machinery today is controlled electronically and even already operated autonomously, the theoretical preconditions for the data acquisition is already fulfilled. But up to now, there was no way of cost effectively exchanging the process information with databases, simulation tools and other enterprise level software. Any data exchange problem had to be solved by individual and expensive software development projects. To solve these problems, the International Rock Excavation Data Exchange Standard (IREDES) was launched in 2000 by major players in the industry. The task of this initiative is to define a ?common electronic language? for easy and standardized data exchange between mining machines and central computer systems. As in other industries, this standard is expected to have significant impact on the use of automated equipment. It shall provide easy ways of using multi vendor machine installations in data controlled mining processes. At the same time it reduces cost for individual development of interfaces for all parties involved. The standard?s technical architecture is flexible and open - also for future applications. It uses modern technology enabling easy data exchange with commercial databases as well as open on line networking.

May 1, 2003

By C. Poon

For slope stability, knowledge of major and minor discontinuity sets that form the rock mass fabric is paramount for pit slope designs. Due to the increased awareness of health and safety in mining projects, efforts have been made to limit structural mapping in order to minimize the risk to personnel associated with approaching potentially unstable areas. Recognizing the importance of such safety precautions, Golder Associates Ltd. is applying a combination of techniques including 3D photogrammetry, conventional mapping and drilling with core orientation to enhance structural data collection. Photogrammetry uses digital photographs to produce a virtual model of a rock mass surface. The application of these techniques will be exemplified through an expansion design of an existing open pit. A comparison of stereonets obtained using these techniques showed some agreements, but also highlighted limitations of each method. The application of photogrammetry was found to be very useful in complementing the other existing techniques.

May 1, 2009

By Emmanuel John M. Carranza, Martin Hale

Abstract- An application of logistic regression to mapping of gold potential in the Baguio district of the Philippines is described. Categorical map data such as lithologic units and proximity classes of curvi-linear features, based on spatial association analyses, are quantified systematically and used as independent variables in logistic regression to predict the probability for presence or absence of gold mineralization. Regression experiments to compare between using all independent variables that are associated spatially with the response variable and using only statistically significant independent variables are performed. The results of the regression experiments are similar; however, the use of all independent variables produces slightly optimistic results but better prediction rates for the known gold deposits in the test district. At least 68% of the ‘model’ large-scale gold deposits and at least 76% of the ‘validation’ small-scale gold deposits were predicted correctly. The predicted geologically favorable zones are also similar to delineated geochemically anomalous zones. The technique presented using logistic regression as a data integration tool is effective for geologically constrained technique of mapping mineral potential.

Jan 1, 2001

By K. Sawada

Along with the expanding demand of copper concentrate in Asian countries, custom-smelters have confronted with difficulties of low TC/RC. Now, Japanese Copper Industry have 2 options; investment in mine development and/or recycling of copper scraps. The strategy of global mining companies is analyzed, and implications for Japanese Copper Industry will be discussed from the viewpoint of sustainability of smelters in Japan.

Jan 1, 2014

By P. J. Poirier, J. A. Meech, H. Raabe

"An Expert System has been implemented to assist operators in applying knowledge about froth conditions in the control of the flotation circuit at Highland Valley Copper. For some time, the personnel at Highland Valley Copper have recognized that froth type is a useful indicator of good operating conditions. However, the operating strategy based on froth type recognition is an ad-hoc skill in which different operators use a variety of terms, features and procedures to identify and solve problems. The first phase of this project developed an on-line consultative system to advise and tutor so that the diffuse expertise could be rationalized and consolidated into a standardized format.The second phase has brought this knowledge into a real-time environment to advise the operators on the floor in identifying froth types and troubleshooting corrective action. This paper describes the steps taken to acquire the knowledge, to design the required system features and to implement the real-time version of this system.INTRODUCTIONThe use of expert systems in the mineral industry has been gaining popularity in recent years. Minnova Inc, Les Mines Selbaie, Wabush Mines, Potash Corporation of Saskatchewan are just a few examples of Canadian mining companies that use expert systems to monitor or control their plants. Applications in the field of flotation include Brenda Mines (Edwards, 1992), Mt Isa Mines Ltd (Lacouture et al, 1991), Outokumpu (Karhu, 1989) and Kidd Creek (Burrows et al., 1989).Expert systems are defined as ""computer systems that apply reasoning methodologies on knowledge in a specific domain in order to render advice or recommendations much like a human expert"" (Turban, 1988). The main areas of application are diagnosis, training, process monitoring and control, and design. There are basically two main types of expert systems: Consultative systems, which are off-line applications in diagnosis and design, and on-line realtime systems, used for supervisory process control and real-time advising."

Jan 1, 1993

By Bian Xue, Wu Wenyuan

High quality, mono-dispersed, hollow CeO2 microspheres with high surface area were produced by a spray pyrolysis method at 700oC. CeCl3 was used as the raw material of the process rather than Ce(NO3)3 because the latter is relatively difficult to obtain in industrial quantities. X-ray diffraction and electron microscopy results confirm the high quality synthesis of hollow CeO2 microspheres with narrow size distribution, good mono-disperse, and good reproducibility. The process of the formation of mono-dispersive CeO2 microspheres was investigated by chemical dynamics and a possible mechanism is proposed. This simple method for synthesis of CeO2 microspheres is easily scaled up to fabricate other metal oxide nanostructured materials at industrial scale.

Jan 1, 2014