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By Moatassem Abdallah

Buildings in the United States account for 72% of electricity consumption, 40% of energy consumption, 13% of water consumption, 39% of carbon footprint, and 30% of waste output. In order to minimize these negative environmental impacts, many public and private owners are requesting that their buildings be more sustainable and certified under the widely known programs such as leadership in energy and environmental design for existing buildings (LEED-EB). To accomplish this, buildings are increasingly integrating green building measures including energy efficient lighting, motion sensors, thermal pane glass, geothermal heat pumps, EnergyStar rated HVAC systems, photovoltaic systems, and wind turbines. This research paper presents the development of an automated decision support system (DSS) that is designed to optimize the selection of green building measures which can be used to upgrade existing buildings. The developed DSS incorporates two optimization models that are capable of (i) minimizing the total upgrade costs required to accomplish a specified LEED-EB certification level such as silver or gold; and (ii) maximizing the number of accredited LEED-EB points within a specified budget of upgrade costs. The DSS is designed to identify a set of optimal upgrade decisions that accomplishes these two optimization objectives. An application example is used to illustrate the capabilities of the DSS and to validate its result.

Aug 1, 2013

By I. Farr, M. R. Mock, J. C. Robison

"HPAL and POX autoclave vapor-space gasses are vented through an autoclave PCV (Pressure Control Valve). The downstream steam-born mist of liquid droplets and solid particles travels in excess of 1000 m/s with megawatts of kinetic power at temperatures up to 160 C. The characteristics of downstream states often result in problems with corrosion, erosion, noise and vibration. Comprehension of those and related characteristics aids in improved pressure control, overpressure control and autoclave level control. We introduce compressible multiphase flow concepts and constructs germane to such flow including choked flow, continuous phase change, shock waves and supersonic flow plumes. Flow modeling based on first principles quantitatively predicts such flows providing a tool for component sizing and a method to estimate effects of water injection on flow. Insight deduced from modeling aids in mitigation of afore mentioned problems of which we share some from-site examples.INTRODUCTION First principles related to fluid thermodynamics and compressible flow have been employed akin to their application in the rocket industry. We will present the results of the application of those principles conceptually and authentically without mathematical rigour while using language of the pertinent disciplines. The autoclave (AC) vapor space over the slurry of a POX (Pressure Oxidation) or HPAL (High-Pressure Acid Leach) system (depicted in Figure 1) is vented via a PCV (pressure control valve) followed by certain ducting, and perhaps a nozzle, before exiting at atmospheric (typically) pressure. As indicated by its name the PCV controls the AC pressure as the flow control component of a pressure control loop."

Jan 1, 2017

By Ray Walton, Ron Colquhoun, Ken Thomas, Dwayne Fentie, Barney Burke

"The new Roasting Facility at Barrick’s Goldstrike Mine in Nevada, U.S.A. was developed to process 12,000 tons per day of refractory gold ore. The process consists of crushing, dry grinding, roasting, extensive gas purification, calcine quenching and leaching in the presence of activated carbon. The new plant is integrated into the existing Goldstrike facility, treating ore from both open pit and underground sources.The process design, procurement, construction and commissioning of the Roaster facility was performed successfully over a 3% year period with peaks of 400 engineering personnel and 950 construction personnel supporting the project. The US$330,000,000 project was completed ahead of schedule and under budget. The commissioning was well planned and proceeded smoothly through a rapid start-up to achieve all primary goals within three months of the start of processing of ore.BACKGROUNDAs early as 1992, Barrick’s Goldstrike Mine, located north of Carlin, Nevada had indications of the ore becoming ever increasingly carbonaceous in nature. As the open pit and underground exploration programs proceeded to step out over the years that followed, the accumulative amount of carbonaceous refractory ore and tons had become significant. By 1997, 29 million tons of double refractory carbonaceous ore containing an estimated 11.6 million ounces of gold had been identified. By 2000 the resource had increased to 14.3 million ounces."

Jan 1, 2001

By L. Garrigues, M. Jarvis, M. Halhead, O. A. Bascur

"Large variability of ore types, escalating variables operating costs and increased throughput require large investment in sensors and systems in mineral processing operations. Mining and mineral processing plants collect and manage more data than a small city with much in real-time. The data is changing rapidly as internal and external conditions evolve. As corporations buy and sell assets, and reengineer their staff, the structure and tools that were used to understand this data is lost. This results in significant deterioration in the ability to maintain a smart operation. When data is recognized as a critical asset and managed as part of an infrastructure, it become a key enabler to help transform the entire operations. In many situations, all partners in business collaboration—such as join ventures, contract manufacturer, expert service providers, and operations and maintenance companies—need access to production and asset data. The emergence and maturation of Cloud technologies make it possible to easily connect the plants to external equipment suppliers and operational support service.This paper will share examples of how mineral processors have adopted new data strategies such as self-service business intelligence, cloud computing and internal/external collaboration.INTRODUCTIONOne of the main challenges in mineral and metallurgical processing plants is effective energy and water management. The lowering of ore grades requires higher throughputs while the ores are getting more complex with variable mineralogical compositions. Electrical energy supply is becoming a restriction in many countries. Rising water management costs has a direct impact on the profitability of the operations. Grade recovery versus energy consumption in copper production for both open pit and underground mines has been described by Fuerstenau (2001). Comminution uses over 55% of the energy to produce nonferrous metals while other operations require much less energy (Nelson, Richins, & Lelinski, 2013)."

Jan 1, 2016

By R. G. Bradburn

"Brenda Mines Limited is a low grade open pit mining and milling operation located near Peachland, British Columbia. The mill was brought into production in late 1969 at a rated capacity of 24,000 tons per day. Tt currently treats an average of 30,000 tons per day of an ore that has an average grade of 0.130% copper and 0.030% molybdenum.Description of Crushing and Grinding CircuitsRun of mine ore is delivered to a primary gyratory crusher. The minus seven inch product is separated into plus and minus one inch fractions on two parallel vibrating screens. The fine product is conveyed directly to the mill fine ore bins, while the coarse fraction is sent to a 45,000 ton stockpile.Material from the stockpile is fed to two standard cone crushers which operate in an open circuit with five secondary vibrating screens. The minus five-eighth inch product from these screens is conveyed to the mill fine ore bins while the coarse fraction is fed to four shorthead cone crushers. These crushers operate in closed circuit with the screens."

Jan 1, 1981

By Min-Sung Kang

Excavation and earthmoving equipment mostly operate in accident-prone areas. These areas normally have rollover, confinement, and fall or may be considered harmful work areas due to demolitions and sewage removals. It is inevitable that excavation and earthmoving systems should be developed to secure the safety of operators through unmanned and remote control systems. Therefore, this research proposes a system that enables excavators to be unmanned and remote controlled without any renovation, remodeling, change, or transformation by applying attachable and separable mechanism and modules. Moreover, this research proposes the sensor module to evaluate the dynamic status without processing remodeling or transformation the existing hydraulic drive excavation system by adopting the easy attachable and separable mechanism. The study verifies this proposal based on observed possibility and feasibility through the experiments.

Aug 1, 2013

By T. G. Joseph

A strain-softening constitutive relationship is introduced that describes the post-failure stress-strain curve for rock regardless of whether the rock is intact or broken. The core of this relationship is an ?apparent friction? concept that relates the post-failure apparent cohesive and frictional characteristics of the rock to the strain. The relationship can be determined for a given rock via a series of tri-axial strength tests establishing the peak strength and corresponding strain for a range of confining pressures, together with the determination of the base angle of friction via a simple tilt test. The postulates and assumptions used in deriving this relationship are verified from results of tri-axial tests on both intact and broken rock.

May 1, 2002

By G. Lipsett, S. Dessureault

Information technology (IT) initiatives in the past have tended to be sold on their ability to maximize resource output and return on capital by allowing assets to be used more effectively and efficiently. Many IT projects fail, not delivering return on their investment. This is known in the IT industry as the “productivity paradox,” where increasing investments in IT do not result in comparable increases in productivity. Experiences and studies of most business sectors reveal that this paradox is rooted in the false assumption that more IT spending automatically results in financial benefit, whereas the benefits are in how effectively IT is used. Most business sectors have accepted that re-engineering of processes is required to gain the full benefits promised of IT. A mining operation has organizational processes similar to most business sectors, but unique operational processes. The lessons of changing business practice in more common business processes, such as inventory control and customer-supplier relationships, can be adequately transposed into a mine setting. The unique operational processes in mines, in turn, require unique redesign efforts. Several enabling information technology opportunities have recently become available, such as more integrated mine production management systems and tactical manager training simulators. This paper reviews some of the latest IT products and outlines the processes and kinds of change that will be required in order to benefit from these new investment options.

Jan 1, 2009

By Denilson Coutinho, Euler Soares, Paulo de Tarso, Jordana Ferreira, John R. Goode, Andreas Sprecher, Alexandre Rocha

The Serra Verde Project is located in the northern part of Goiás state, Brazil, and comprises 49 mineral claims covering an area of 69,814 ha. The Serra Verde deposit is a rare earth element (REE) enriched weathered granite comparable to the weathered granite, or ionic-clay, deposits found in southeastern China. The Mineral Reserves of the Serra Verde Project total 388 Mt (Measured and Indicated) at an average grade of 1,484 ppm of REE oxide (REO). Several hundred agitated leach and column leach tests have confirmed recovery of about 40 to 55% of the REE, except for Ce, using simple desorption techniques. Present plans call for a heap leach operation followed by precipitation of impurities and precipitation of a pure REE carbonate suitable for refining and separation. The project plan includes initial production of 5,000 t/a of REO, with a high content of heavy and critical REO, rising to 10,000 t/a of REO. This production rate will be obtained by mining of the Mineral Reserves over a 22-year mine life at an initial rate of 6 Mt/a for the first four years with the mining rate thereafter increasing as required by grade and production targets.

Jan 1, 2014

By Joseph L. Fournier

Suncor Oil Sands employs delayed coking technology in converting bitumen into synthetic crude oil. Currently up to 10,000 m3 of delayed coke (coke) is produced per day as a byproduct of the upgrading process, of which up to 9,000 m3 per day is placed in dry storage on Lease 86/17. A review was completed to examine the case history of leachate potential experiments from the dry storage of coke and the environmental relevance of coke leachate studies conducted over the past decade. The review included an evaluation of the potential impacts of environmental conditions within the location of coke storage, including precipitation pH, as well as daily and annual ozone trends. Coke leachate potential has historically been characterized using standard leachate testing protocols (i.e., TLCP, SPLP) together with other studies that have employed strong acids and oxidizing agents in the extraction fluids. The present paper highlights prevailing conditions in the Athabasca Valley air-shed with emphasis given to ambient ozone (oxidizers), as well as precipitation pH and acid input deposition rates, and will demonstrate that TCLP / SPLP tests lack the intended environmental relevance relative to the conditions under which coke is stored.

May 1, 2011

ABSTRACT The inevitable uncertainty in modelling spatial variables decreases as more data become available. This reduction depends on the properties of the variable being modelled. Spatially continuous variables show less uncertainty for a given spacing than erratic variables. A geostatistical simulation based approach is developed to quantify the relationship between uncertainty and data spacing. Reference realizations are sampled to condition additional realizations and quantify uncertainty. The procedure is automated, making it straightforward to consider sensitivity and different geological domains. A case study of the relationship between uncertainty and data spacing for net oil sands thickness data from northern Alberta is presented. _ KEYWORDS Simulation, Sampling,

Jan 1, 2013

By I. G. Townsend, S. A. Buckley, C. I. House

"SummaryBritish Petroleum plc is developing a new gold recovery process known as coal gold agglomeration (CGA) for the recovery of gold from its ores. Liberated gold grains are recovered with high efficiency by adhering to agglomerates of coal and oil. The process is simple, can recover gold grains down to very fine sizes, avoids the large scale use of cyanide and provides the industry with an important new process option.A technical appraisal of the process has been performed on an extensive range of gold bearing materials. Ore types have been identified from which high gold recoveries can be achieved. A spreadsheet based computer program has been used to estimate the preliminary capital and operating costs of the process. Comparison with established gold production costs shows that the process costs of CGA, on the appropriate ore types, are potentially very attractive, which will enable economic treatment of lower grade ores than is currently possible using conventional cyanidation. Treatment of known placer deposits or gravity concentration plant tailings may be the most rapid means of demonstrating the process at a commercial scale prior to more widespread applications.1. INTRODUCTIONWestern world gold production for the 1980s has shown rapid growth sustained by a demand for gold at a favourable price (Fig. 1). Heap leaching and CIP/CIL operations have been responsible for the major part of new production during the 1970s and 1980s with present overall production costs averaging US$200/oz in Canada, USA and Australia and US$265/oz in South Africa [l]. A great deal of research and process development effort in the 1980s has been towards the treatment of refractory ores. Operating costs for the economic processing of these ore types by currently available routes are around US$300/oz [2]."

Jan 1, 1989

By A. Hynes, T. Skulski, D. Francis

The Archean volcano-sedimentary succession in the LG-3 area has undergone two phases of deformation and has been metamorphosed to upper greenschist and amphibolite facies. Marine, fine-grained sediments and mafic pyroclastics comprise the lowest observed stratigraphic unit. These sediments are overlain by a thick sequence of submarine basalts and minor basaltic andesite. The lavas are characterized by high Al/Al+Si, Ti values, low Mg numbers and flat REE profiles (lOx chondrite). A sedimentary prism of coarse elastics which was deposited close to an exposed plutonic highland, overlie the volcanics. Massive lavas of basaltic andesi te and associated volcano-sediments comprise the uppermost stratigraphic unit. These lavas are characterized by high Mg numbers, Ni, Cr, LREE (lOOx chondrite) but low Ti, Al/Al+Si and HRee. The supracrustal rocks were intruded by tonalites and tonalitic gneisses.

Jan 1, 1984

By Mario A. Morin

The last few years have seen considerable consolidation of the mining software industry and a trend towards greater planning and production control system integration, particularly for surface mines. The mining industry is starting to realize the benefits of system integration and will continue to drive the evolutions of these systems. Several trends can now be observed. The trends include application and system integration, data portability, ?intelligent? systems for support of decision-making activities, mine process-control and automation. While many planning systems are moving in this direction, there is room for considerable improvements. This paper will discuss these trends, examine the current state-of-the-art in mine design software, and identify areas where improvements should be made and why.

May 1, 2004

By M. R. Coffin

In recent years, improved operation of the Kidd smelter has resulted in an increase in blister production capacity. Due to manpower and equipment limitations anode production and treatment rates could not be increased without incurring significant additional operating expenses. The option chosen to expand casting and refinery capacity to meet the available blister supply was to increase the anode thickness while maintaining the same anode exchange cycle in the refinery. This has resulted in a cathode production increase of almost 10% for minimal expenditure. Equipment and process modifications required to cast and refine the thicker anodes are discussed in this paper, along with the Six Sigma methodologies used to identify them. Key areas covered are Hazelett continuous caster operation, refining process parameters, plating performance and cathode quality.

Jan 1, 2007

By Q. Dong, S. A. Nightingale

An investigation has been carried out to assess the effects of an applied voltage on the dissolution rate of MgO refractory in a steelmaking like slag. In this study corrosion results obtained from dip tests using a dense direct bonded MgO refractory in a CaO-SiO2-Fe2O3-FeO-MgO slag are presented. These results demonstrate that the application of a voltage across a dense MgO refractory-slag interface can change the rate of refractory dissolution. For the slag composition used and the voltage range tested, it was found that a maximum corrosion rate was obtained at a voltage setting of -0.45V. The results of this investigation have been explained in terms of voltage affects on Marangoni (interfacial tension induced) stirring and its effect on the MgO dissolution reaction that is at least partly controlled by mass transfer in the slag.

Jan 1, 2004

By R. A. L. Drew, F. Edelmann

Brazing is a low-cost process used extensively in the manufacturing and repair of aircraft gas turbine engines. Components within the compressor stage of the engine experience relatively low temperatures (600-700°C), therefore joints of stainless steels are typically employed. In such joints, a Pd-Ni-Cr-Si-B (PalNiCroTM) brazing alloy is used as a sealant, however brazing procedures are not well understood. The wetting behavior of PalNiCroTM on AISI 347 was evaluated with respect to contact angle. A microstructural evaluation was carried out with variable joint clearances. Microhardness profiles were performed to investigate the presence of hard secondary phases, which were later confirmed by electron microscopy. The results indicated an equilibrium contact angle of 10° within 100 seconds. The average microhardness of the braze layer and base metal were approximately 550 and 205 VHN, respectively. At the interface, a diffusion zone was present containing carbides and borides.

Jan 1, 2004

By R. J. Grant, D. W. Scott, M. A. Cooper, E. R. Shannon

"The Brunswick No.12 site concentrator processes 10,500 tonnes per day of a complex lead, zinc, copper and silver ore producing four concentrates by differential flotation. Research over the years has led to increased understanding about the mineralogical and flotation characteristics of the ore. A pilot plant study conducted at Lakefield Research, primarily designed to investigate the technical feasibility of semi-autogenous grinding, provided an opportunity to test recent theories about grind size,, reagent schedule and flowsheet configuration.A fundamental approach was taken with each of the unit processes involved in grinding and flotation. Basic operating and metallurgical criteria were established in each area and a step-by-step implementation program initiated in the plant.Significant improvements in metallurgical and financial performance have been realized through the application of basic grinding and flotation principles using conventional milling equipment and without major capital expenditure. Current operating practice is detailed and metallurgical advancements cited.INTRODUCTIONBrunswick Mining and Smelting operates one of the world's largest lead and zinc mines near Bathurst, New Brunswick. Brunswick is a publicly traded company with majority ownership held by Noranda Minerals (63%). In addition to the No. 12 underground mine, the company operates a lead smelter and phosphate fertilizer plant in Belledune, N.B. and maintains a 25% interest in a joint venture with Noranda Minerals' Heath Steele mine near Newcastle, N.B. Through the four operations, a total of 2000 people are directly employed with fixed assets totalling Cdn$187 million (BM&S, 1991)."

Jan 1, 1993

By Samantha A. Beeson, Colin Poole

"A selective flocculation-floe flotation technique is already in use in the Canadian potash industry for the removal of water-insoluble slimes, but the process is currently limited in its application and reagent consumption is high. The work described in this paper details investigations into the separation of sylvite and halite from water-insoluble slimes by selective flocculation utilising other commercially available polymers.Preliminary flocculation performance tests were undertaken on pure sylvite, halite and water-insoluble minerals to establish the importance of a number of experimental parameters. The data from these single mineral tests was then used to establish optimum parameters for the separation of sylvite and halite from a synthetic mixture similar in composition to a typical potash ore. Under optimum conditions, separation was achieved with high recoveries using dispersant and flocculant dosages significantly lower than those currently used in plant practice.IntroductionAlthough solar evaporation and solution mining are used in some operations, most potash is extracted by conventional underground techniques and is then processed by froth flotation, in order to separate the valuable sylvite (KCI) from halite (NaCl) and water-insoluble gangue minerals. Flotation is usually preceded by a desliming stage to remove water-insoluble fines, but this also results in high potash losses and affects process brine requirements. To overcome these problems, one plant operated by Cominco in Saskatchewan uses a selective flocculation -floe flotation process (Banks, 1979/1980), in which a polyacrylamide flocculant is added to produce floes of water-insoluble material with minimal incorporation of halides. A collector is then added to render the floes hydrophobic and suitable for removal by froth flotation.A number of workers have also investigated the use of selective flocculation in potash processing, but these too have been concerned with developments in the removal of water-insoluble slimes (Williams, 1960; Brogiotti et al, 1974; Chan et al, 1986; Thompson et al, 1979; etc.). This paper provides results of novel investigations into the selective flocculation of sylvite and halite from water-insoluble minerals and discusses the possible mechanisms involved."

Jan 1, 1995

By N. Katsikaros, N. S. ‘ Yap, B. Adaszynski

"Cyanide is a well proven, effective lixiviant that has been utilised for centuries in gold extraction processes. Despite being used in close to 90% of gold processing plants, cyanide leaching is still being scrutinised due to its toxic nature. With governments tightening the regulations on cyanide management, and recently erected sites situated closer to community and environment, leach waste and tailings treatment has become increasingly important. Gekko Systems has worked with engineering companies and directly with gold producers to provide technical services and supply complete modular cyanide destruction (detox) systems for plants leaching both run-of-mine ore and high sulphide gravity and flotation concentrates. Although similar in principle, the different materials presented unique challenges in design and implementation. Similar to designing any section of a processing plant, the development of the cyanide destruction plant design began with laboratory test work to simulate the full scale operation. This paper focusses on the laboratory test work and how other critical factors such as geographical location, logistics, and local community play a role in the process design and construction. Two design and supply cases are discussed in this paper; one treating intensive cyanidation concentrate leach tails and one treating whole ore CIL tails. Although these plants both use the SO2/O2 process, each presented different challenges in laboratory testing and plant design, resulting in variations in final implementation including reagent choice, oxygen supply, and process control.INTRODUCTIONSince 1887, cyanide has played a large part in the beneficiation of gold from gold bearing ores. Cyanide is used to solubilise gold into solution, and is typically added in excess to maintain the leaching process. Some or all the excess cyanide can often be recovered and reused in the process however chemical destruction of cyanide is often necessary to manage cyanide levels in the tailings storage facility (TSF)."

Jan 1, 2016