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By Jeff Stufsky

Debt Financing ?Broad Market Overview ? Recovering due to factors including: ? Increased trust in the system ? Enhanced capitalization of financial institutions ? The need to deploy capital for profit ? Competition: ? Investment-grade bond volumes increasing dramatically, and starting to pressure banks to compete with new capital ? Term Loan B financing from insurance companies and related institutions is returning, also pressuring banks to lend ? Local country financial institution capacity in Latin America has materially increased ? Results: ? Loan capacity increasing generally across instruments, regions, and sectors ? Financial institutions/banks starting again to seek yield as pricing competition heats up ? Tenors increasing with pricing coming down more slowly Underwriting is back in play

May 1, 2010

By N. W. D. Davis

"As I have recently carried out some further research on the Navan lead-zinc deposit data while working in Michel David's research team, I should like to add a few comments on the paper- ""Universal Kriging for Ore-Reserve Estimation- Conceptual Background and Application to the Navan Deposit"", by M. Dagbert and M. David (CIM Bulletin, pp. 80-92, February 1976). The first comment is that since this research has been carried out, important new theoretical advances have been made which make for an easier application of geostatistics to the non-stationary case (see Matheron0l). This is the theory of intrinsic random functions of order k. With the aid of this theory, it has been possible to write computer programs which can carry out automatically universal kriging, although so far such applications have been largely confined to automatic contouring and not to mining problems. However, if approached with care there is no reason why these methods should not be applied to mining problems and, in this case, an automatic study has been done on this data."

Jan 1, 1976

By T. Thriveni, Ji Whan Ahn

"The current advanced technologies for the manufacture of light weight metals processing significantly increasing and attributes to the safety, performance, recyclability and economy. Still lack of technologies developed for light weight metals processing waste utilization and application. Environmentally friendly methods need to develop for better understanding the processing waste utilization. Alumina and aluminium processing creates a wide range of waste products, the most significant being is red mud. Bauxite residue is a high volume hazardous waste and nearly 3 billion tons have been dumped worldwide. Approximately, 120 Million tons/yr of red mud being produced without any environmental sustainable solution. Currently the most significant technology is waste utilization. The bauxite residue is suitable for road base construction, golf bunker sand, back fill and, general fill. Sustainable recycling technologies are necessary for the bauxite residue utilization for the recovery of rare earth elements and cement materials. Carbonation or CO2 sequestration of carbon dioxide is a method pioneered for the bauxite residue is modified to reduce alkalinity. The carbonation of alkaline material is an inexpensive and safe process that leads to the formation of thermodynamically stable products. The use of the carbonation can be an advantageous solution for environmental climate change and sustainability problems in the new century.INTRODUCTIONIn 2014, bauxite consumption was estimated to be 9.6 million tons, nearly all of which was imported, worth an estimated 269 million dollars. More than 95% of the bauxite was converted to alumina, and the remaining 5% went to non-metallurgical products, such as abrasives, chemicals, proppants, and refractories. Global aluminum demand is growing steadily spurred by growth in India and China (RBCAluminum Market Outlook, 2013) (Figure 1). Aluminum consumption is expected to rise 5% annually through the end of the decade, reaching 67 million tons per year by 2020. Global bauxite production decreased by 17% from that of 2013, principally owing to lower production in Indonesia. In response to a Government ban on exporting bauxite and other unprocessed mineral ores that took effect on January 12, 2014, bauxite mines throughout Indonesia shut down and production decreased from 55.7 million tons in 2013 to an estimated 500,000 tons in 2014. The ban was part of a mining law that was instituted in 2009 to increase development of downstream processing facilities in Indonesia."

Jan 1, 2016

By J. Etcheverry, E. Seguel, R. Díaz, F. Parada, R. Parra, E. Balladares

A thermodynamic and kinetic model is proposed to explain the formation of bornite, chalcopyrite and magnetite during partial roasting of enargite-containing copper concentrates. The proposed mechanism involves solid-solid-gas and solid-gas reactions between chalcocite, pyrrhotite, gaseous sulfur and oxygen. The formation of bornite could be explained by a two-step reaction: the first one involving the formation of chalcopyrite by a reaction between Cu2S, FeS and gaseous sulfur, followed by a second step in which the newly formed chalcopyrite reacts with additional chalcocite to form bornite. Although thermodynamically the direct formation of bornite is more favorable than that of chalcopyrite, the lower diffusion kinetics of bornite formation could explain the preferential formation of chalcopyrite. If the reaction occurs with stoichiometric chalcocite and pyrrhotite in the presence of gaseous sulfur to form chalcopyrite, no bornite is formed, while for the stoichiometric reaction between chalcopyrite and chalcocite in the absence of sulfur, only bornite is formed. For the formation of magnetite and chalcopyrite the mechanism could involve the partial reaction of chalcocite and pyrrhotite in the presence of oxygen. The proposed model is thermodynamically consistent with the experimental results obtained in laboratory and pilot plant. INTRODUCTION The processing of high-arsenic copper concentrates with over 0.7 wt.-% arsenic by conventional smelting-converting normally require an additional arsenic removal step to reduce arsenic content to levels below 0.2–0.3%. One of these high-arsenic copper concentrates is the one produced by the Ministro Hales Division (DMH) of CODELCO, which has the typical chemical composition shown in Table 1. Enargite (Cu3AsS4), chalcocite (Cu2S) and pyrite (FeS2) are the main mineralogical species present in these concentrates, with over 75 wt.-%, as shown in Table 2. Partial or “neutral” roasting of these concentrates under controlled temperature and partial oxygen pressure conditions at 923–993K (650–720ºC) can remove up to 95% of the arsenic as As2S3 (As4S6), which has a high vapor pressure under these conditions, leaving a calcine with low residual arsenic. In copper concentrates, arsenic is present generally as enargite and arsenopyrite. This compounds as well as others such as pyrite and covelite, decompose readily above 770 K (500ºC), releasing, in addition to gaseous arsenic trisulfide, gaseous sulfur which by oxidizing to SO2 generates most of the heat required by the process.

Jan 1, 2019

By M. Sider, D. L. Piron

"The cost of energy is a growing factor in the cost of zinc production. Electrowinning from sulphate solutions with periodical reverse current or from acidic chloride or alkaline solutions could be the way to lower costs. A comparison of the energy consumption for electrolysis shows that the alkaline solution may be considered the most promising alternative. IntroductionZinc electrowinning from sulphate solutions is a very energy intensive process (typical specific energy usage : around 3.1 kWh / kg zinc). This energy consumption represents 35% of the total cost of electrolysis and is the most important cost component.In order to lower costs, the energy efficiency of the sulphate process should be improved or alternative processes should be developed. In this laboratory, that objective has resulted in research on electro winning in sulphate solutions with the use of periodical reverse current (PRC) and in acidic chloride and alkaline solutions.Some of the results obtained in this laboratory and already published and new experimental results reported in this paper make it possible to present a more critical comparison of the energy consumption of the three processes mentioned.ExperimentalThe experiments at constant current were carried out as described previously. Specific conditions are indicated in Table I. Current efficiencies were obtained by weighing deposits.ResultsThe best energy consumptions for electrolysis obtained in this laboratory for the three media are presented in Table I. More detailed results can be found in the papers already mentioned."

Jan 1, 1988

By Nancy C. Mohn

?Even though the age of many existing coal units exceeds 30 years, these units continue to perform with excellent reliability and at a competitive cost with other fossil fuel units. ?NERC data shows a consistent increase in availability for all utility coal generation ?With the opening of power markets, the challenge for coal is to produce competitive electricity while meeting increasingly stringent, and costly environmental limits. ?During the 60s and 70s, subcritical steam power plants dominated the market. The emphasis was on scale-up to larger MW size units. ?In the last decade, we have seen interest in a broader set of technologies with new drivers: ?Fluidized bed technology was developed to respond to increased environmental requirements, particularly with lower quality fuels ?Supercritical pressure units have gained interest for both fuel cost savings and reduced emissions due to higher efficiency.

May 1, 2001

By Sabine Noelte, Mikko Petteri Rantamäki, Christopher Robben, Anssi Takala, Karl-Erik Rånman

"Sensor-based ore sorting is on its way to establish as a standard option for physical separation. The increasing number of installations in coal, iron ore, industrial minerals and hard-rock metal mining segments underlines the technological and financial potential that is beginning to be untapped. The Ma’aden Phosphate installation with 1.650 t/h sensor-based ore sorter feed sets a new benchmark for the possible capacity of stationary installations. Besides stationary installations, including multiple sorters parallel in different size ranges and multiple stages, containerised semi-mobile plants are applied. These offer two advantages, first being the reduction of transport costs when applied close to the mining face. The second is that semi-mobile systems enable processing of tens of thousands of tonnes of ore in a piloting phase with an approximate duration of 0.5 to six months, verifying the results laboratory mini-bulk tests on 5–10 tonnes of sample. This is especially important for low-grade metal ores because of the inherent Fundamental Sampling Error, as well as the Grouping and Segregation Error. The paper elaborates the results achieved within the I2MINE project, treating polymetallic ore at the Boliden Concentrator in Sweden.INTRODUCTIONSensor-based ore sorting (SBS) is becoming a standard option for physical separation, applied in all segments of mineral production. The Umm Wu’al project sets the bar for stationary SBS installations with 1,650 t/h feed (TOMRA, 2015). TOMRA Sorting Solutions has finalised an agreement in cooperation with Outotec to supply Outotec-branded sorting solutions for the mining and metallurgical industry (TOMRA, 2014). Especially for low-grade hard rock metal ores, an interdisciplinary approach is necessary applying experts for all aspects of mineral production. Due to the impact on the whole process stream, it is important on the end user side to have high level managerial support and involve all disciplines to ensure that all stake holders are involved in the analysis."

Jan 1, 2016

By Donald Leroux, Robert Grant

"Flotation is a complex and highly multivariate process. Using the conventional OFf (one-factor-at-a-time) technique, the optimization of flotation circuits through laboratory or plant testwork is difficult, time-consuming and therefore, expensive and often results in marginal improvements. The optimal operating conditions can be more efficiently estimated when a systematic approach like SDE (Statistical Design of Experiments) is taken.The concentrator of Noranda's Brunswick Mining Division (near Bathurst, New-Brunswick) is well known for the complexity of its differential copper-lead-zinc flotation circuits. One of them, the chalcopyrite-galena separation (or CuSep) circuit, is impacted by more than 20 variables.Statistical Design of Experiments (SDE) techniques were applied at the laboratory scale to improve the performance of Brunswick's CuSep circuit. Screening tests were conducted using Fractional Factorial designs while optimization tests were carried out based on Response Surface Modelling techniques like the Central Composite design. Every series of tests, without exception, revealed new information and process insights which led to significant circuit performance improvements in the plant So far, the metallurgical gain may be as high as four percentage points of copper recovery (in the CuSep circuit). Potential cost savings of expensive consumables (steam, activated carbon) have also been identified but will require additional circuit modifications before being realized.IntroductionIn spite of its apparent simplicity, flotation is a complex three-phase (solid, liquid and gas) separation process. Fundamentally, it is a highly multivariate process. Industrial flotation circuits are commonly affected by 10 or more process variables."

Jan 1, 1997

By Mitchell Gordon

"In almost all thickener applications the highest possible solid/liquid separation efficiency is what is desired by the user. There is a trend in the industry due to monetary restraints and environmental pressures to look at ways to extract this maximum performance by either retrofitting existing thickeners or installing the most cost effective new thickener. This paper looks at some of the common problem areas and presents a range of solutions developed by Outokumpu Mintec in North America and outokumpu's subsidiary Supaflo Technologies Pty. Ltd.The Emerging PictureAfter many hours of discussions with a large number of plant personnel over the last two years a picture began to emerge regarding current thickening operations in the industry. Initially, it seemed that everybody had their own unique process problems and therefore needed a correspondingly unique solution. Looking more closely at all the cases and the ideas that we had either implemented or suggested, it gradually became apparent that the majority of operators all had one and the same process need ....""Better Separation Efficiency""The range of operational problems that were uncovered in the survey were much more varied than expected and often were not even considered initially to be thickener problems. Often, it was only after the rejection of many solutions to the problem, generally due to capital cost, that the actual cause of the problem was looked at and found to be a thick-ener.A summary of the problems that have so far been identified is presented in Table 1. They are subdivided under three major categories of environmental, process and paste fill to highlight the wide range of mining activities that can be affected by poor thickener performance. These seem to be the major areas where the need for better separation efficiency is rooted."

Jan 1, 1995

By K. Thuro, H. Käsling, F. Menschik

"With increasing data volume, due to enhancing requirements for ground investigation programs for large construction projects, the demand for more efficient filing systems is more and more growing. Depending on the project we also have to use flexible systems to cope with varying data out of different lab and field tests.The chair for Engineering Geology at TUM is developing a web-based database solution to handle all project relevant data in a more appropriate way. We aim to optimize our data management to achieve a fast and easy way of collecting, documenting and analyzing our gained data. The second objective is to provide an easy access to our data for project partners across broadly distributed locations.This Database system consists of a PHP web interface and a MySQL database core. The current setup allows an online access via Internet (www). We are able to grant and constrain access to all data or only arrays of data with our user management system to guarantee the safety of project data and respect all rights and proprietorship. The database system is of modular design and consists of the following three base modules: module of general project data, module of laboratory data and user management module. At the current stage we are able to save and work with all usually generated specific values from unconfined compressive strength tests, brazilian tensile strength tests, point load tests, CERCHAR and LCPC abrasivity tests and ultrasonic tests. The user is able to perform a simple statistical analysis within our database (e.g. average calculation of one sample) and export data as csv or xls files for further analysis.For specific questions within projects we are able to deploy and integrate further modules in our database system. At this moment, we are developing an add on to use this database for different drill test analyses. One of the tools correlates drilling performance and drill head wear measured in the field with rock mechanical properties, and extrapolates the data to estimate the performance and wear in new projects. Today we are managing 90 projects with 550 samples and almost 1350 lab tests with the base module.In our contribution we aim to demonstrate an efficient way of data structuring using a relational database for laboratory and field testing data."

Jan 1, 2015

By Robin E. Goad

?Located 160 Km northwest of Yellowknife, NWT, Canada Current winter road access ?New all-weather road planned ?Power within 22 km ?Hwy to Edmonton 80 km south Close to existing infrastructure

May 1, 2006

By Aalbert Zwijnenburg

One of problems connected with the use of gold/titania-based catalyst systems is the low yield in propene oxide (up to 2 wt %). It is shown that the low propene oxide yield is due to product inhibition. New options for propene epoxidation with hydrogen and oxygen are discussed. INTRODUCTION The direct gas-phase synthesis of propene oxide (PO), by the use of molecular oxygen, is still aimed for. Agbased catalysis is in principle possible, but selectivity at present is not promising. Highly dispersed gold on titanium containing catalysts show an extraordinary selectivity in the oxidation of propene to the corresponding epoxide (> 99 %), using a combination of H2 and O2 as oxidation mixture [1]. Additional studies of the epoxidation reaction have indicated several drawbacks of the Au/TiO2 catalyst. Firstly, the low conversion (1- 2 %) obtained under typical reaction conditions (atmospheric pressure, 323 - 423 K) cannot be increased by increasing the reaction temperature, because this leads to extensive by-product formation. Secondly, the low efficiency of hydrogen (relatively large amounts of water are formed) is hard to prevent. Finally, significant deactivation of Au/TiO2 catalysts within several hours on stream has been observed. Deactivation can be almost completely prevented by using dispersed TiO2 supports, such as TiO2/SiO2 and Titanium-Silicalite-1 (TS-1) [2]. In recent literature [2,3] a hydroperoxide-like intermediate has been proposed to be responsible for the selective epoxidation. This oxidising species is said to be formed over gold and subsequently used for epoxidation over the Ti-containing support. The support is responsible for the slow desorption of PO. One of the problems for future industrial application might be the low yield in propene oxide. Furthermore, the presence of minor amounts of by-products, not detected on lab-scale catalyst testing, might complicate the separation unit in an industrial process. The reason for the low PO yield over Au/TiO2-based catalysts will be discussed in this paper. Temperature Programmed Desorption (TPD) and micro-flow experiments have been carried out to study PO desorption and catalyst performance, respectively. A catalytic cycle is proposed together with its consequences for the maximum yield in PO. Finally, several process and catalyst options are discussed in view of potential future industrial application.

Oct 1, 2003

By Bong Sun You

AZ31 magnesium plate of 300mm in width and 40mm in thickness was produced by horizontal continuous casting machine, and its microstructures were analyzed on the surface and in the plate interior. The defect formation on the surface and subsurface, such as side cracks, buckling, pores and segregation, was very sensitive to the casting condition and processing parameters. Especially, casting speed and secondary cooling were the most dominant parameters to control the solidification behavior of magnesium melt, for example the position and shape of the solid/liquid interface in the mould. The cyclic marks on the surface were obvious because the plate were drawn by 4-step cycle and can not be removed. The average grain size of as cast plate measured as 50-65µm at the near surface and 300-400µm in the center of the plate was relatively small because secondary cooling water was applied to control the surface quality resulting in rapid solidification of the melt in the mould.

Jan 1, 2006

ABSTRACT The SART (sulphidization, acidification, recycle, and thickening) process is an effective way to separate copper and cyanide in the waste stream of gold processing plants using cyanidation. Factorial experimentation has been conducted to create models of copper recovery, cyanide recovery, acid addition, and oxidation/reduction potential during SART. Economic analysis of the resultant models showed that SART is best operated with a sulphide-to-copper molar ratio of approximately 0.56, pH of 4, and a minimized cyanide-to-copper molar ratio. The experiments also showed th0at residence time can have drastic impacts on SART performance.

Jan 1, 2013

By Carl Faessler

Abstract Some Canadian geologists believe chat, in the Grenville sub-province of Eastern Canada, there is no granitic intrusion older than the anorthosite. The writers are among those who hold the contrary view. They suggest a new means to distinguish between rocks belonging to intrusions respectively older (Laurentian) or younger (Pine Hill) than the anorthosite. This new method is based on microscopical observations which demonstrate that the Pine Hill intrusives contain a large amount of exsolution perthite, whereas the Laurentian intrusives are completely devoid of exsolution perthite. Where perthite is present in Laurentian rocks, it is the result of lacer hydrothermal replacement. Introduction The present paper is the result of a systematic study of some acidic intrusive rocks in the Grenville sub-province. These rocks underlie large areas of the Canadian shield in the Province of Quebec, mostly along the southern border of the shield.

Jan 1, 1946

By Asanga S. Nanayakkara

The surface deformations induced by reservoir dilations can be measured using tiltmeters and these measurements can be used to infer reservoir level volume changes by solving an inverse problem. Preferred approach to solve such an inverse problem is to consider more tiltmeter measurements than the number of unknown variables considered in the inverse problem. However, sufficient number of measurement points is not always available due to economical and practical issues. This paper proposes a new approach to circumvent this problem. The new approach entails generation of pseudo surface deformation data by curve fitting tiltmeter measurements using a mathematical function, which delineates three-dimensional characteristics of surface deformation profiles. Then a three-dimensional inverse problem is solved using pseudo surface deformation data. This method is useful in inferring reservoir volume changes with high areal resolution when the number of available measurements is not sufficient to acquire the desired areal resolution.

Jun 1, 2012

By Jaana Romppanen, Satu Jyrkönen, Tiina Ranki, Peter Björklund, Markku Lahtinen, Kaj Eklund, Päivi Suikkanen

Outotec is continuously developing our existing process equipment and new equipment solutions to enhance the Flash Smelting process. Thanks to the long operating history of the Outotec Flash Smelting process feedback from the numerous operating references are available and is utilized. The general goals for development work are to improve equipment performance, thus realizing savings in Smelter plant operation costs by increasing the process efficiency and online availability. Digitalization also opens new possibilities for the feeding equipment and furnace operation monitoring. These solutions will improve the safety and performance of the smelter, and provide process and equipment related information which has not been available earlier. INTRODUCTION The year 2019 marks the 70th anniversary of Flash Smelting. The technology was operated on industrial scale for the first time at the Outokumpu Harjavalta copper smelter in Finland in 1949. The Flash Smelting technology, is now owned and developed by Outotec Oyj and the first plant, is now owned by Boliden Harjavalta Oy. The two companies have been evolving throughout history by optimizing the process for various feeds and raw-materials, as well as through developing the equipment and operating practices. Even though sustainability was not a hot theme/topic during the first days of Flash Smelting, it has nevertheless been the key principle in guiding the development. This is well proven by the wide adoption of Flash Smelting for the processing of copper and nickel concentrates, mostly due to its ability to fulfil the economic and resource efficiency criteria demanded by its operators. Along with the process technology development, also development of the equipment has taken place over time. Outotec is continuously working on developing our equipment to better suit the changing need of our customers in the continuously changing operational environment. Orebodies are getting more challenging with lower ore grades and more impurities. Achieving high recoveries for all valuable elements becomes more difficult with high slag quantities and with the need to tackle the high impurity concentrations. There is a need for higher capacities in greenfield and brownfield smelters. The role of the Loss-in-Weight Feeder, the Air Slide and Concentrate Burner is to ensure even feed into the reaction shaft of the Flash Smelting Furnace, and to enable controlling the process well, thereby enabling the best performance for the customers smelter. The design of the Flash Smelting Furnace aims for high availability, long campaign and safe operation.

Jan 1, 2019

By H De Beer

The 14MW SAG mill at Tarkwa, Ghana, experienced a frozen drop charge incident on 10 February 2010. This caused downtime of 112 hours, a repair cost of $200k and production loss of 162,000 tons, corresponding to a loss of $8.9M. A new locked charge protection system was installed on the two Tarkwa mills on 30 July 2010, mitigating this risk. This system calculates the ore angle in real time while the mill is starting up and trips the mill if the ore angle exceeds a trip angle setting. The calculation of the ore angle is derived from the mill motor rotor currents only - no mechanical transducers are required. The head of Gold Fields West Africa, Peter Turner, says of the new system: "This is excellent work and the type of technology that has had and will continue to have, major opportunity cost impacts on our business."

Nov 1, 2011

By P. van Zyl, M. Lombaard

The 14MW SAG mill at Tarkwa, Ghana, experienced a frozen drop charge incident on 10 February 2010. This caused downtime of 112 hours, a repair cost of $200k and production loss of 162,000 tons, corresponding to a loss of $8.9M. A new locked charge protection system was installed on the two Tarkwa mills on 30 July 2010, mitigating this risk. This system calculates the ore angle in real time while the mill is starting up and trips the mill if the ore angle exceeds a trip angle setting. The calculation of the ore angle is derived from the mill motor rotor currents only - no mechanical transducers are required. The head of Gold Fields West Africa, Peter Turner, says of the new system: "This is excellent work and the type of technology that has had and will continue to have, major opportunity cost impacts on our business."

Jan 1, 2012

By Chen Feng

Compared to widespread successful deployment of robotic manipulators for repetitive and hazardous tasks in related industries such as manufacturing, the construction industry has achieved relatively limited benefits from robotics and soft automation. Unlike manufacturing, where robotic solutions benefit from the structured layout of the environment (e.g., factory assembly line), construction robots face unique challenges that arise from the rugged, dynamic, and unstructured environment of the work site, as well as the uncertainty and evolving sequence of occurring on-site events. This challenges any intended construction robots to not only replicate basic human motion, but also be capable of sensing and adapting to environmental changes, and making decisions based on the evolving state of the environment. Building upon recent advancements in robotic mapping, computer vision, and object recognition, the authors propose to introduce autonomous behavior at the basic task level for on-site construction robots to address these challenges in a flexible and extensible manner. This paper reports the outcome of the first phase of this research - a structured methodology for improved design and development of basic task automations - and focuses on algorithms developed for mobile robot navigation and relative pose estimation. The algorithms are implemented on a prototype mobile robotic platform, and evaluated in several experimental scenarios.

Aug 1, 2013