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By Oberlando Gonzalez, Claudia Serna, Andrea Alzate, Esperanza López, Maria Holuszko

This paper presents a systematic approach on gold recovery from electronic waste (e-waste) using ammonium persulfate. This process was developed as a response to the lack of hydrometallurgical systems capable of separating gold from its metallic substrate without material grinding, with minimum formation of pollutants, and achieving a lower reaction time. Computer memory boards, electronic processors and electronic pins and contacts were analyzed to determinate base metals (Ni, Fe, Cu) and gold (Au) using microwave plasma atomic emission spectroscopy (MP-AES). An aqueous commercial grade ammonium persulfate with oxygen and pressure was used to produce the persulfate anion (S2O82-) and the oxidative sulfate ion (SO42-), which partially oxidized and leached the base metals breaking the Au-Ni-Fe-Cu bonds and allowing gold to be recovered in its original non-leaching state. The influence of the oxidative parameters was evaluated using full factorial (FF) and central composite designs (CCD) with response surface methodology (RSM) and first and second order models were developed. Using RSM allowed to obtain a faster recovery of gold, minimizing the agent consumption. The findings presented suggest that optimized quantities of ammonium persulfate, oxygen, pressure, temperature and liquid solid ratio could be used for selective oxidization of the base metals and to extract more than 96% of gold from e-waste.

Jan 1, 2017

By Andre L. Du Preez

Global mine hoisting regulations require safety fall arrest systems to be installed on vertical conveyance systems capable of safely decelerating and supporting a fully loaded conveyance in the event of a rope severance. Most current arresting systems are incapable of producing controlled safe deceleration rates. Although safety ?dogs? achieve marginally acceptable results on wooden guides, difficulties arise in achieving safe deceleration performance requirement where safety arrest systems operate on steel shaft guides. Previously, arresting systems capable of operating with steel guides have been incapable of producing controlled deceleration rates during the arresting of free-falling conveyances. Most are ?instanton? systems, whereby an occupant inside a conveyance being arrested would be subjected to unacceptably high deceleration forces. This paper briefly highlights the background to the selection process of Rio Tinto?s Technical Staff of a suitable Mine Conveyance Safety Fall Arrest System for #1 Shaft at Rio Tinto Oyu Tolgoi Mine, Mongolia. It also describes the Drop Test and Free Fall Test procedure and the results leading to the acceptance of the Horne Group Levelok® Emergency Braking Technology for the Oyu Tolgoi #1 Shaft in Mongolia. The paper highlights Rio Tinto?s primary objective for the selection of this advanced technology on their primary production shaft cage system as an emergency safety catch braking system combined as an advance hydraulic chairing system. It describes the design and operational parameters and the 'Fail to Safe' interfacing with current automated mine hoist systems.

Aug 1, 2013

By M. Côté, H. Pépin, Y. Richer, C. Gingras

Rolls-Royce Canada has been nominated as a Rolls-Royce Center of Excellence for repair of fan blades in 2003. One of the challenges of the Rolls-Royce Canada Component Repair Center of Excellence team is to reduce cost and time of inspection while ensuring trace ability and quality of the inspection performed on the fan blades. In the context of the dimensional control process optimization, and following the positive conclusions of initial trials carried out in 2003, the technical authorities at RRC have selected the SPG data 3D(TM) technology as a development base for dimensional control programs. The main goal of this development initiative is to develop and support an inspection system to perform the dimensional control and inspection of different components at the Montreal Fan Blade Repair Center of Excellence. The final objective of the program is to build a server platform capable to support different inspection sites within the Montreal facility for the future. This paper presents the certification process of the technology according to the VDI-VDE 2633 certification standards and some results of the fan blade inspection program of the BR 710, BR 715 and TAY according to the JES 195 engineering standards specification.

Jan 1, 2006

By J. B. Kwon

For improvement in the productivity of tall building projects, table formwork is one of the main methods that have been adopted for slab formwork. Because the table formwork method is an equipment-oriented construction method, the type of lifting equipment and method of operation considerably affects the productivity and cost of the table formwork. It is also important to make an equipment input plan for completing the table formwork within the time given, according to the structural construction cycle. For performing the table formwork, a tower crane or an independent lifting system, and shifting trolleys, are required. However, if an inefficient equipment input plan is made, exorbitant cost may be incurred. Therefore, the purpose of this study is to analyze the productivity of a table formwork, considering the type and number of lifting equipment and the number of trolleys inputted, and to suggest quantitative data for making a cost-efficient equipment input plan within the construction duration given. It is expected that the results of this research will be utilized as a basis for cost-efficient equipment input planning.

Aug 1, 2013

By E. S. Moore

Introduction The geology of the Sudbury nickel field has been studied extensively, but there are few reports dealing with the structure of the interior of the basin. It was not until the Treadwell-Yukon zinc-lead deposits were discovered that attention was strongly directed toward the large-scale faulting that has split the basin parallel to its long axis. This faulting has been responsible for the , ore deposits in the basin and it may be regarded in many ways as the most important geological event, next to the intrusion and differentiation of the nickel eruptive sheet, that has occurred in the Sudbury region. The early reports on the nickel region by Bell, and Barlow, were chiefly concerned with the nickel-copper ores and with the formations of the region. Coleman was the first geologist to map the nickel eruptive as a continuous sheet around the belt and to emphasize its basin character. On the map accompanying his later report, he shows an important offset in the nickel eruptive at its southwest end, where the large fault cuts this portion of the basin, but the fault was not traced into its interior, as little detailed work was clone in the basin at that time. No ore-bodies had been developed outside of the nickel-copper deposits associated with the norite when the map was prepared, and attention was mostly concentrated on the nickel eruptive. Coleman did, however, map and name the various formations found within the basin and, in general, his delineation of these has remained the standard for prospectors and other workers in the field until the present day.

Jan 1, 1930

By K. Ihara, T. Yamaguchi, K. Matsumoto

"Al-Fe alloy sheets having layers with different strain components were produced by unlubricated hot rolling and the recrystallization texture formation during annealing was investigated in each layer. In this study, the strain component introduced by rolling was quantitatively evaluated by measuring degree of bending of an aluminum pin embedded in the sheet. The textures before and after annealing were investigated by the SEM-EBSD technique. It was clarified that, in the middle layer, where comparatively small shear strain was introduced, ß-fiber subgrains and cube {001}<100> oriented subgrains were formed before annealing, and cube oriented recrystallized grains grew after annealing. On the other hand, in the surface layer, where large additional shear strain was introduced, shear texture components and cube oriented subgrains were formed before annealing, and shear texture was retained even after annealing, while cube oriented subgrains did not grow and were encroached. It was suggested that introduced strain components influenced the recrystallization texture formation by inducing different distribution of the subgrain size, stored strain energy and orientation relationship with surroundings before annealing.INTRODUCTION The microstructure developed during the hot-rolling process of aluminum and aluminum alloys affect the mechanical properties of the final product sheets. Especially, the crystallographic orientation in the final product sheets affects the r- value and ears during deep drawing (Humphreys & Hatherly, 2004), then the texture control in the hot-rolling process is important. When the friction between the rolling roll and rolled sheet in the hot-rolling is large, both the rolling texture and recrystallization texture tend to be heterogeneous in the thickness direction. It is known in many rolled aluminum alloy sheets that the texture in the surface layer was different from that in the middle layer because of additional shear strain. It was reported that in the vicinity of the surface layer, where large additional shear strain was introduced, the shear texture <1 1 1>//ND and < 1 1 0> // RD which contain components of {1 1 1} <1 1 0> and {0 0 1} <1 1 0> developed during rolling, and the shear texture developed even after recrystallization annealing (Sakai et al., 2002). Particularly, it is thought that the <1 1 1> // ND texture contributes to improve the r-value and press formability (Inoue & Takasugi, 2007). Therefore, asymmetrical rolling and high friction rolling have been applied to improve formability of aluminum alloys by adding shear strain in the rolled sheets as deep as possible (Kamijo et al., 1972; Inoue et al., 2005). However, few researches have been focused on the microstructures and texture before annealing and thus, the detailed mechanism is still unclear how the texture after annealing is affected by the texture before annealing. In this study, the Al-Fe alloy of commercially pure aluminum was chosen as the first material to be studied in order to clarify the fundamental process of the recrystallization texture formation. The main purpose of this study is to clarify the effect of additional shear strain on the rolling and recrystallization textures in the hot-rolled sheets by analyzing the transition of microstructure and orientation distribution through recrystallization annealing."

Jan 1, 2018

By S. Nikolic, H. M. Henao

"There is renewed interest in the improvement of existing copper smelting processes and the development of new technologies. It has become clear that further accurate information on slag properties, in particular, on phase equilibria are required in order to optimize these processes. It is in this context that improved experimental research methodologies have been developed specifically to provide information on phase equilibria at the oxygen partial pressures encountered in copper smelting practice. The methodology involves synthetic slag equilibration at controlled gas atmospheres, quenching and measurement of compositions of phases with an electron probe X-ray microanalyser (EPMA) with wavelength dispersive detectors (WDD). Application of modem analytical tools and careful design of experiments greatly improve accuracy of determination of phase equilibria in complex, multi-phase slag systems. New experimental data on phase equilibria for the copper smelting and converting silicate slags at controlled oxygen partial pressures in the temperature range between 1200°C and 1350°C in the ""Fe0""-Ca0-SiO2 system and in the ""Cu20""-""Fe0""-Ca0-Si02 system in equilibrium with metallic copper are reported, and differences between various data sources are analyzed."

Jan 1, 2007

By K. H. Poulsen, C. J. . Hodgson

Synvolcanic, layered gabbro-anorthosite sills at Rainy Lake, Northwestern Ontario, reflect a combination of igneous processes including fractional crystallization, wall rock assimilation and possibly liquid immiscibility. Chalcopyrite-pyrrhotite mineralization at the base of the Grassy Portage intrusion accumulated by crystallization of a sulphide liquid during cooling. Upward enrichment of Fe and Ti in this intrusion and also in the Bad Vermilion Lake anorthosite complex culminated with the crystallization of lenses of disseminated to massive magnetite+ apatite+ ilmenite+ rutile. Regional low to medium grade metamorphism and accompanying deformation resulted in recrystallization and local remobilization of ore minerals.

Jan 1, 1984

By Nehad Elsafty

It is always necessary to expand existing buildings, so that they could meet the growing societal needs. Compared with demolishing them and then constructing new ones, the expansion of existing buildings could not only reduce project cost, but also save the use of energy and raw materials in projects. Therefore, it is widely adopted in most under-developed countries. However, the expansion of existing buildings is not an easy task. It has been involved with a lot of issues in defining the scope of work, planning landscape, managing construction activities, etc. This paper investigates the potential challenges in expanding existing buildings. The project of expanding the Al-Agoza Hospital, one of the biggest and oldest hospitals in Cairo, Egypt, is selected as a case study. In the case study, the project documents have been carefully reviewed. The project engineers and the health-care professionals working in the hospital have been interviewed. This way, the point of views from the owner, the architect/engineer, and the contractor have been taken into account. Several lessons are learned through the discussion with these people. The results from this paper are expected to provide pieces of useful advice and suggestion for the expansion of existing buildings in the future.

Aug 1, 2013

By B. D. Frater

Geometallurgy or process mineralogy is an integrated part of the scoping, pre-feasibility and feasibility phases of a project as well as an existing operation. A well planned and executed geometallurgical testwork programme during the early phases, will result in a more accurate decision making process during the selection phase. The better this integration between geological, mining and metallurgical data gathering during the early phases, the more accurate the predictions will be with regards to throughput and recovery during modelling and process and equipment selection in later phases. This will enhance and improve the mine and process scheduling and subsequent NPV. Geometallurgical information gathered during plant operation and testwork can for example be used to statistically model the pit optimisation, plant throughput and optimise the plant for certain feed material (characterised by statistical models).

Jan 1, 2017

By Yan-Jun Shen

The rock mass classification system, BQ (basic quality), is the only national system that is suitable to most kinds of rock engineering in China. It uses two main aspects of the rock mass, the intact uniaxial compressive strength (UCS) and the rock intactness index (KV), to obtain the rock mass BQ. The index KV could be measured by the acoustic wave method. However, because this method is an indirect approach to characterize the rock mass structure, misfits often occur between the test results and the actual rock mass characteristics. Therefore, a new parameter KGSI expressed by the geological strength index is proposed to replace the original KV, and a new method is presented to express the value of BQ as a function of the UCS and the KGSI. Then, the underground excavations at five hydropower stations were chosen as examples to study the relationship between the revised BQ and the each of the international systems (RMR, Q or RMi). In addition, the applicability of the RMR, Q, or RMi system is discussed for China?s rock characteristics and geological conditions, and suggestions are given for improving the revised BQ system.

Aug 1, 2013

By Shengwu Song, Xuemin Feng

Jinping I hydropower station is located in Sichuan Province in Southwest China. It is built on the Yalong River as a controlling cascade hydropower station in the middle and lower reaches, with power generation as its major function. Jinping I arch dam concerns many engineering issues and has attracted worldwide attentions due to its huge scale and unique settings. It is one of the most challenging projects in China with its 305 meters high arch dam and complex geological conditions for construction, including large-scale tectonic faults, intensively unloaded rock masses and geological asymmetry in its foundation. At present, the concrete arch dam construction has been completed and preliminarily impounded, most of the foundation treatments have been implemented, and four of six generator units had been put into operation in July 2014. In this paper, the analytical methods, design concepts, treatment measures and technical features of strengthening the geological defects in the dam foundation will be presented. Upon geological investigation into the dam foundation, a few large-scale weak discontinuities are observed. The rock masses in the left dam foundation are intensively unloaded, approximately to the horizontal depth of 150–300 m. These serious geological defects lead to a geological asymmetry on the left and right banks, and thus some major difficulties of dam construction are encountered. The influences of geological defects on the dam construction and safety are analyzed comprehensively, followed by the concepts and methods of treatment design. Based on this, the treatment methods of the weak rock masses and discontinuities are carefully determined by numerical analysis and scheme optimization, including the concrete cushion, concrete replacement grids, drainage system, anti-seepage curtains and consolidation grouting, which work together to enhance the strength and integrity of the dam foundation. Evaluations and calibrations through geo-mechanical model tests in combination with field monitoring results in early impoundment period show that the arch dam and its foundation are generally stable and function normally, which suggests that the research methods and treatment design schemes are reasonable and effective. The proposed treatment methods and concepts in the context are helpful for similar complex rock projects.

Jan 1, 2015

"These guidelines set out information on timely disclosure of news releases which are intended to provide, existing shareholders and potential investors, factual information on which a reasoned investment decision can be made.Consider the problems and concerns raised by the following hypothetical news releases:Natural Resource Company""The Company has recently optioned a large and exciting gold property near the ""XXX"" gold discovery area. In describing the property, the Company's independent consultant has said: ""The favourable location of, and some of the results of prior work done on the property give the Company a worthwhile mineral exploration opportunity .... "". The Company proposes to expeditiously conduct a sizeable exploration program on the property as soon as the appropriate financing has been arranged.""Non-Resource Company""Based on discussions with several European countries, the Company anticipates that it will have orders to ship over 200,000 crates of widgets to those European countries over the next two years. These orders, which considerably exceed the Company's forecasts for the first year, represent a projected profit to the Company in excess of $1,000,000 over the next five year period.""GuidelinesTimely disclosure news releases are intended to provide, to both existing shareholders and potential investors, factual information on which a reasoned investment decision can be made. National Instrument 43-101 Standards of Disclosure for Mineral Projects provides requirements for disclosure of a scientific or technical nature for a mineral resource company.The examples do not provide sufficient detail and are misleading because material information is omitted. The following guidelines should be observed when preparing a news release:"

Jan 1, 2003

By Lan Vu

"The Ferderber mine consists of a series of Archean gold-bearing quartz lenses within a shear zone that crosscuts the central part of the quartz diorite Bourlamaque batholith. This zone has sharp contacts with the enclosing quartz diorite, and on average strikes N70E and dips 65SE. Along the contact with the shear zone, the quartz diorite is chloritized, sericitized and carbonatized. The chlorite schist within the zone is probably derived from mafic dykes.The geometry and distribution of structural features within the Ferderber shear zone suggest a long history of repeated movements. The majority of gold-bearing lenses were first emplaced during a probable early period of brittle shear which resulted from strike-slip movement. They were then folded and pulled into boudins by a later episode of reverse movement that accompanied ductile shear. New mineralized veins were emplaced in the shear zone and deformed at this time.Mineralized veins are dominated by quartz, carbonates, tourmaline and micas. Gold is more common within pyrite where chalcopyrite is abundant and is generally in contact with both pyrite and chalcopyrite at ""triple point"" grain junctions. This intimate association suggests that copper may have played an important role in gold deposition.Recent exploration has shown that the Bourlamaque batholith is cut by many parallel or en echelon shear zones. Study of ""Landsat"" and aerial photographs has indicated a number of linear structures striking ENE-WSW and ESE-WNW which form a conjugate system. The intersection of these two structural trends presents an interesting exploration target."

Jan 1, 1990

By Rolf Andreas Lauten, Adam Pratomo, Dani Ramdani, Helminton Sitanggang

A universal challenge for the mineral processing industry is the diminishment of high grade ores. Instead, low grade ores, sometimes also containing problematic gangue minerals is the reality. With lower head grades the industry has to put more effort into processing to maintain the output and achieve suitable recoveries. In an effort to reduce the impact of declining head grade, a biopolymer was evaluated as an additive in the gold leaching operation at Antam Pongkor in Indonesia. Laboratory testing revealed that biopolymer usage lead to an increased gold recovery without apparent negative impact on the other parts of the process. Further plant trials revealed both a recovery increase around 1.3% and higher throughput (9%) in the presence of the biopolymer. Some scenarios that can explain these findings will be discussed.

Jan 1, 2014

By O. Engler, J. Friis, S. J. Andersen, C. D. Marioara, Y. Aruga

"This work investigates the early stages of precipitation in Al-Mg-Si alloys using a combination of high angle annular dark field scanning transmission electron microscopy (HAADF-STEM), selected area electron diffraction (SAED) and density functional theory (DFT) calculations. Quenching from a high temperature (solution) treatment leaves an alloy in a high-energy unstable state, with solute and vacancies in supersaturation. Thus, already at room temperature (RT) a large driving force exists for solute atoms to cluster and order on the Al matrix positions. DFT calculations indicate that strain alleviation is important at this stage. We observe larger regions of Mg-dominated L10 ordering together with a Si-dominated ordering of smaller clusters in a particular geometry connected to the Si-network found in all the precipitates. In addition, building blocks of the main hardening phase ?'', stabilized by vacancies, are observed at higher, typical pre-aging temperatures.INTRODUCTION Al-Mg-Si (6xxx) alloys are widely used in industry due to a combination of favorable properties such as strength, ductility, corrosion resistance and lightweight. They undergo a complex production route, usually consisting of the following thermo-mechanical steps: casting, homogenization, extrusion or rolling, solution heat treatment (SHT) and artificial aging (AA). The SHT takes place at temperatures above the solvus line in the phase diagram, usually between 500°C and 570°C, followed by a rapid cooling to RT. This ensures that high amounts of solute atoms, uniformly distributed on the cubic face-centered (FCC) Al lattice, together with a large amount of vacancies, are quenched-in. The material is therefore in a super-saturated and unstable state. During the subsequent AA, at temperatures usually between 150°C and 220°C, the solute atoms diffuse and cluster, forming metastable precipitates with needle/ lath/ rod morphologies having the main growth direction along <100>Al. With a maximum alloy solute level (Mg + Si) of only 2%, these precipitates increase material strength up to three times that of pure Al, and are essential for the final material properties. To understand and make better use of this phenomenon, it is imperative to research the nature of the precipitates (such as their atomic structure), measure their key parameters (number density, size, volume fraction) and connect it to material properties (Marioara, Andersen, Zandbergen & Holmestad, 2005; Marioara et al., 2014). The following precipitation sequence is given for the Al-Mg-Si system:"

Jan 1, 2018

By T. Ward, K. Shah, K. Murray

The mining industry is processing deposits with ever decreasing grade at ever increasing operating costs while margins are under constant pressure by material substitution and recycling. We are reaching the point where building it bigger just isn’t good enough as social and environmental constraints become more intense. In response to the growing demands on our industry, Goldcorp has embarked on a journey to increase resources by converting Waste to Ore. Gravity pre-concentration and sensor sorting testwork has been completed on samples from our Canadian operations in order to determine the amenability of our mineralized waste to sorting and upgrading. As expected some material was amenable to sorting and a review of the economics supported demonstration plant testing. The ability to economically sort mineralized waste into ore and barren rock is being demonstrated by Goldcorp. It has been made possible by leveraging the experience mineral sizer manufacturers have gained in the oil sands and hard rock applications, seeking more energy efficient screening machines and embracing the advancements that ore and recycling sorter suppliers have achieved. The paper will discuss the testwork and results achieved to date from both the lab and demonstration plant.

Jan 1, 2018

By J. Chretien

The ability to continuously monitor the air quality within a mine has become instrumental in becoming a low cost producer. The many considerations involved in monitoring air quality include sensor type, hardware placement, as well as data storage medium. BESTECH has had the opportunity to gain insight into these air quality monitoring considerations through deployments of NRG1-ECOTM, a minewide energy consumption optimization system. This paper explores the particular challenges overcome through these installations, and provides a set of guidelines for mines that want to maximize data capture while minimizing costs. It provides a view of additional benefits of air quality monitoring, such as ventilation control, reporting and trending.

Aug 1, 2013

By J. H. Starkey

Large differences between macro and micro grindability relationships have been discovered for mill design measurements using the patented SAGDesign(TM) test. Crushing, Rod and Ball Mill Wi tests, and breakage parameter measurements have previously been used to design SAG mills but have not revealed the true magnitude of these differences. A SAGDesign(TM) test measures the SAG/Bond Wi Ratio (defined below) for every sample tested and gives a good design result because the F80 of the SAG stage test feed is 19 mm and because the test includes a Bond Ball Mill Work Index on SAG ground ore. Good flotation operation demands properly sized grinding mills and steady feed to the flotation circuit.

Jan 1, 2009

By Freislich. M., Y. Gordon

"In the changing global market scenario for raw materials for the steel industry, a number of novel iron- and steelmaking process technologies are being developed to provide the steel companies with economically-sustainable alternatives for iron- and steel-making. In addition, the steel industry is also focusing on reduction of energy consumption as well as green-house gas (GHG) emissions to address the crucial subject of climate change. In this context, it is important to assess these critical issues for the alternate iron- and steelmaking technologies that have been developed. This paper presents a comparative evaluation of energy-efficiency and GHG emissions for some selected iron- and steelmaking technologies that are being considered for implementation. In this work, Hatch’s G-CAP™ and En-MAP™ tools that were developed with the main objective of quantifying and qualifying the potential energy savings and CO2 abatement within the iron and steel industry, were employed in the evaluation conducted. INTRODUCTIONThe iron and steel industry continues to transform itself and evolve in the ever-changing global market place – the raw material scenario is constantly changing with respect to quality and quantity (availability), there is stiff competition in both global and local markets, and there is increasing pressure to address global climate change issues, especially since the steel industry is highly energy- and carbonintensive. There is growing importance of steel production in developing countries such as China and India – this means that the steel industry in these countries will play an important role in defining and shaping the future of the industry.Climate change is expected to present new risks to the steel industry with respect to ensuring a sustainable business. Legislators are proposing to limit GHG emission by placing an implicit price on CO2 emission - market-based “cap and trade”, carbon tax etc.. In this scenario, it is important for the steel companies to reduce exposure to climate-related risks and at the same time, find business opportunities within these risks. Thus, there is a need to strategically manage the climate change risks; the key steps to strategically manage climate change risks are presented in Table 1[1]."

Jan 1, 2012