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By J .. R. Dalton

"Blasting in high sulphide content ores presents at least two major safety considerations: (1) compatibility of the explosives with the ore while resident in the borehole; and (2) introduction of a flame and shock producing explosive into this environment, while minimizing the risk of reactive ignition in the chemical reaction products/sulphide dust cloud resulting from the detonation. This paper will discuss only the second consideration, i.e. post detonation reactivity.The ETI (Explosives Technologies International) Technical organization, in consultation with the U.S. Bureau of Mines, reasoned that the most relevant considerations in the development of an explosive for this application are:• minimization of reactive gaseous detonation reaction products;• flame duration reduction;• flame temperature reduction;• increased explosive sensitivity;• reduced probability of ""low order"" detonation; and• maintenance of energy level as high as possible.Obviously, not all of these are totally independent properties, i.e. increased sensitivity will reduce the probability oj low order detonation as will higher energy levels. However, these considerations were examined separately as if they were independent."

Jan 1, 1994

By Michel Ruel

Most plants do not track how their systems perform. Optimization is the easiest way to benefit from your control systems. We suggest an approach in four phases. The first phase is to assess all equipment to determine the performances for instruments, valves, variable speed drives, and other equipment. The second phase is to remediate instrumentation problems, including the ones pertaining to valves, variable speed drives, analyzers, transmitters. When equipment is in order, loops are put back in automatic mode. If a loop oscillates, use standard default values for this type of loop. The third phase consists in validating the control strategies, properly configuring the systems (control system, programs and parameters, HMI, alarms), and then tuning the loops and control strategies. The fourth phase consists in analyzing the process and expected performances in order to optimize the control loops and control strategies. If performance is not sufficient, a decision tree will be presented to determine the right approach: advanced regulatory control, model predictive control, or fuzzy logic control. Once all steps have been completed, control performance monitoring software is used to sustain the results and pinpoint equipment or loops not performing as stated. Alarm management and rationalization could also be performed after auditing the alarm system, if needed. Examples from plants will be used to demonstrate how this step-by-step method is applied and produces results. INTRODUCTION Maximizing what you already have is the best investment to remain competitive. This article aims to show the benefits of a systematic approach using modern tools to improve plant performance. We at BBA suggest dividing the work in four phases, and a subsequent phase can begin when the previous one has progressed: Assess, Remediate, Stabilize, Optimize, or add advanced control. This approach has been successfully applied to several sites. Examples and illustrations from these plants demonstrate how this step-by-step method is applied and produces results. Under the BBA method, there are four questions to answer before proceeding to the next step. For each control strategy, you should ask the following questions: Assessment: Does it work? Remediation: Do you use it? Stabilization: Is it stable? Optimization: Does it perform? Do you need advanced control?

Jan 1, 2019

By Gordon Thompson

"Development of the unique Mine Games exhibition at Science World British Columbia is the largest ever collaboration of many interests to present the story of mining and the issues of mineral development delivered to the public by a science education centre.IntroductionMineral education programs have long been a major focus of the British Columbia mining community. Mine Games and its tremendous potential to enhance industries image and the public's awareness of mining is unequalled in the field of Issue Based Education Exhibits.The main goal of the exhibition is to look at the future of resource industries in a rapidly changing world of economic activities, new technologies, and growing public concern for the environment. Three challenges were the aim of the exhibition: to increase participation, to serve as a tool to increase interest in science and technology, and to draw an increasing number of school students to the interests of geology and the earth sciences. Mine Games is to serve as a meeting place for discussion of issues and where reliable information can be shared and new ideas explored.The exhibition is designed to develop new approaches to hands on learning that encourages visitors to explore and generate discussion and thinking with respect to resource development activities.The role of author, beginning in 1993, was, with senior industry leaders, to coordinate the raising of $1.3 million to complete the funding of the $1.6 million project total. The second and most interesting challenge was to work with the many minds that were collaborating to create the exhibition and to assure that the facts and science were correct. This involved the coordination of ""expert groups"" that verified the science and technology and the issues that the creative design team at Science World planned to use in development of each exhibit module."

Jan 1, 1995

By Rolf Andreas Lauten, Guy Kluck

"Formation of scales may have important detrimental effects in many mineral processing applications. A well-known problem is the need for frequent maintenance to remove scale from processing equipment. Another challenge may relate to encapsulation of valuable minerals in precipitating scale. In this work, we explore the ability of some crystal growth inhibitors to prevent or lower the degree of scale precipitation. In many situations pregnant leach solutions contains substantial concentrations of calcium, magnesium, sulfate and carbonate in addition to dissolved valuable elements, e.g. gold, copper, zinc. Together with non-dissolved gangue minerals, some slurries may also contain particulate gold, copper etc. During normal processing of the pregnant leach solution it may be exposed to temperature gradients or similar promoting precipitation of various scales. Valuable minerals may become entrapped in precipitates and thus become inaccessible to the lixiviant. Use of a crystal growth inhibitor may lower the degree of encapsulation of valuable elements.Using a simple model system, supersaturated with respect to gypsum, the effect of some crystal growth inhibitors on the prevention of scale is evaluated in terms of amount precipitated gypsum, the particle size of the precipitated gypsum and the carbon gold loading capacity.INTRODUCTIONGold bearing sulfide ores are often roasted or pressure oxidised prior to leaching. The purpose of this unit operation is to prevent loading the leaching circuit with sulfides that consume cyanide. Pressure oxidation or roasting chemically converts the sulfides into sulfates and at the same time, the pH of the slurry ends up in the acidic range. Typically, lime addition is the preferred means to raise the pH to around 10 where gold leaching takes place. Combination of large amounts of calcium ions from the lime with sulfate ions from the ore induces precipitation of gypsum. Compounds like calcium carbonate may also precipitate if carbonate ions are present in the slurry. Depending upon the composition of the ore, compounds like calcium carbonate and other types of scale may also precipitate on gold surfaces on the slurry particles. A layer of scale on top of exposed gold surfaces will prevent dissolution in the cyanidation that takes place during leaching. Naturally, such a precipitation may lower the gold recovery."

Jan 1, 2016

By C. Mattich, Å. Holmström, L. Hedström

"The fluidized bed at Division Ministro Hales (DMH) division of Codelco in Calama, Chile is currently the largest operating roaster for partial roasting of arsenic rich copper concentrates. The roaster converts the Mina Ministro Hales (MMH) enargite rich (Cu3AsS4) copper concentrates into calcine with a low arsenic content that is suitable for mixing with other copper concentrates feeding a flash furnace. The plant sets a new standard for the processing of arsenic rich concentrates, both from the quality of the calcine as well as the environmental performances. The process technology and expertise are based on the solid practical experience of treating arsenic rich concentrates from both the Boliden smelter and Outotec.The partial roasting process is located next to the mine and concentrator and includes a sulphuric acid plant with auxiliary equipment. The produced calcine has an arsenic content significantly below target and the residual sulphur meets the requirement of the flash furnace. The plant operates with high efficiency cyclones resulting in a low amount of calcine passing to the hot electrostatic precipitator (HESP). The small flow of HESP calcine dust can be combined with the low arsenic calcine and still meet the flash furnace feed arsenic requirements.SO2 formed during roasting is converted into sulphuric acid, while volatized arsenic is recovered in the wet gas cleaning section of the acid plant along with a large proportion of antimony present in the MMH concentrate. Arsenic is stabilized as calcium arsenate and sent to disposal at a specially prepared site.The present production rate (September/October 2015) is close to or higher than the original maximum design capacity of the plant.INTRODUCTIONMineralogyThe mineralogy of an ore and concentrate is important, since there is a direct link between roasting performance and concentrate mineralogy. The MMH concentrate has a good combination of minerals that makes the roasting process efficient and flexible. The main minerals are pyrite, enargite and chalcocite (Figure 1). The inert content is about 15% and consists mainly of silicate and alumina based minerals. The lead content is very low and this is desirable, since the presence of even a small amount of lead will cause a substantial increase of sintering during roasting."

Jan 1, 2016

By D. R. Wright

"The modest thermal efficiency of the steam turbine cycle essentially determines the heat required and, therefore, the coal consumption and ash production of pulverized-coal-fired powerplants. This paper emphasizes how some properties of coal and its ash can crucially affect the operation of a steam generator and its flue gas cleaning equipment. A brief reference to some siting factors and economics reaffirms the all-pervasive influence of the properties of coal and ash and establishes the importance of a firm supply of cooling water. The economics of scale remains a compelling factor in selecting the size of units, despite disappointing performances by some of the larger units. Environmental considerations suggest that smaller units still have a role to play. IntroductionCoal fuelled one industrial and economic revolution, beginning two hundred year s ago . It was the precursor of competing fuels, notably natural gas, oil and uranium, which eclipsed it in terms of convenience and rate of growth.The turmoil that now exists because of rapidly dwindling supplies of no-longer-cheap oil and the concerns about nuclear energy-justified or unjustified-exacerbated by an operating incident at the Three Mile Island Nuclear Powerplant, prompt speculation for a resurgence of coal, especially where it cangenerate electricity to replace energy from imported oil.The world's reserves of coal are not inexhaustible, although they are ample for several decades. Of greater import is the fact that the world's coal reserve s are more widely distributed than its oil reserves, and they appear less convenient as instruments of economic and political persuasion by opportunist powers. The crux is whether or not the world will accept all that a massive, if temporary, return to coal implies.Combustion of pulverized coal in steam generators to pro duce electricity is a 50-year-old, well-understood technique; it is undergoing continuous refinement to meet evolving environmental and economic criteria and is not found wanting. It is certainly the only technique available and technologically advanced enough to replace oil immediately on a large scale. Although it may take a decade to bring a new coal-fired powerplant into service, this delay is a reflection on nontechnical and administrative processes. Capital and operating costs of coal-fired powerplants are significant and subject to inflation, but, because of the accumulated experience in this field, the ability to control costs is better than for those energy processes which are less mature or still in embryo form. More exotic, soft energy systems, touted as the panacea for world energy problems, have still to prove themselves on the scale they are needed and under the stringent climatic and operating conditions coal-fired powerplants have already mastered."

Jan 1, 1980

By B. D. H. Knights, N. B. du Preez

The recovery of the economy of the Democratic Republic of Congo has allowed for the rapid increase in production of copper from this region, while the increased price of cobalt continues to support the recovery of that country’s economy. This has enabled the modernization of the process technology used, particularly the change from direct electrowinning of copper to solvent extraction-electrowinning. With this change has come a variety of technical challenges in optimizing the recovery of cobalt from these sources. In this paper, we discuss aspects of the flowsheets for the production of cobalt from the ores of the DRC and Zambia, highlighting the technological improvements that have been made. Following this description of the practice, we assess the challenges of further improving the recovery and purity of cobalt from these sources. INTRODUCTION The African Copperbelt (Figure 1) is by far the biggest producer and holds the greatest reserves of cobalt (Sheed, 2015). However, the ores of this great mining region are extracted primarily for their copper content, and cobalt is a by-product. The ratio of copper-to-cobalt is between 6 and 20 to 1, with the ores from the DRC richer in cobalt than those from Zambia. The overall supply of cobalt, shown in Figure 2, is increasing due to an increase in demand for its use as a battery material. Cobalt is used in superalloys, hard metals, pigments, catalysts magnets, tyre adhesives, lithium-ion rechargeable batteries, and wear-resistant coatings, amongst others. Although these generic categories persist, Figure 3 shows how the relative usage of cobalt is changing due to the uptake of electric vehicles in China and Europe. Cobalt is a key element in lithium-ion batteries, and because it is widely anticipated that electric vehicles will be legislatively encouraged, it is anticipated that the demand for cobalt will rise. This anticipated increase in demand resulted in an increase in the price for cobalt, to which suppliers responded over-eagerly, and the price has dropped dramatically in the first few months of 2019, as shown in Figure 4. However, there is a clear cycle of price peaks in cobalt’s history.

Jan 1, 2019

By E. Herrera, L. Mariscal

"Ilo Copper Smelter operates since 2007 with an ISASMELTTM furnace as a single smelting unit (1,200,000 tpy) associated with two Rotary Holding Furnaces for separation of matte and slag, and which directly produces a discard slag. Southern Peru continually has been improving the slag chemistry of its ISASMELTTM furnace in order to reduce copper losses, given its big economic impact due to large slag mass generation. The present paper describes the influence of the CaO, Al2O3 and magnetite content in the slag of the ISASMELTTM furnace correlated with the SiO2/Fe ratio and its liquidus slag. Also it defines the best slag chemistry and operating practice in order to reduce the copper losses without compromise the bricks life of the furnace.INTRODUCTIONIlo Copper Smelter of Southern Peru (Grupo Mexico) is located on the southern coast of Peru, and treats mainly copper concentrates produced in its own mines (Toquepala and Cuajone).The modernized smelter was commissioned in 2007 and operates with an ISASMELT™ furnace as a single smelting unit (1,200,000 tpy), which is associated with two Rotary Holding Furnaces (RHF) for separation of matte and slag. This slag is directly sent to the dump. Figure 1 shows the smelter flow diagram.The ISASMELT™ process is a bath-smelting process using a single lance. The lance tip is immersed into a molten slag bath contained within the stationary, vertical, refractory-lined ISASMELT™ furnace. The injection of oxygen-enriched air, through the lance into the slag results in a highly turbulent molten bath. Feed material falling into the turbulent bath from above reacts rapidly, resulting in extremely high productivity for a relatively small bath volume."

Jan 1, 2012

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 S. Maleksaeedi

On-site evaluation of strength using hardness is common for different materials. The lack of such relation for aluminum alloys has always been felt. In this work, a finite element analysis of plastic deformation and its distribution in Brinell hardness testing is presented. The analysis has been performed for different strength levels of aluminum alloys. By utilizing the Von Mises equivalent strain in hardness, it is tried to derive a correlation between hardness and strength values for the alloys under consideration. The derived correlation is verified using the experimental values available in literature.

Jan 1, 2004

"There are a number of disciplines in the minerals industry for which concern has been expressed regarding the sustainability of human capital. The boom-bust cycles that occur in the industry, the trend in tertiary education towards consolidation or in some cases cessation of minerals related programs and the increasing frequency of fly-in fly-out operations can all contribute towards a decline in the number of professionals with basic skills in process mineralogy. This paper describes approaches taken by the authors to incorporate process mineralogy into three levels of education, namely undergraduate, recent graduate and experienced professionals. The primary objective in designing the learning activities is the development of authentic learning experiences that provide participants with relevant skills in process mineralogy. Selected examples of approaches used by other education groups globally to address this issue are also provided.INTRODUCTIONThe boom and bust cycle of the mining industry has trickle down effects in tertiary education in terms of the ability of universities to consistently provide high quality graduates with relevant skills. When the commodity price surged in 2002 skills shortages in critical resource related professions were reported and despite investment in skill development there was a view from employers that not enough young people were graduating from relevant education programs (PricewaterhouseCoopers, 2012). At the time this signalled positive growth for engineering disciplines catering to the mining industry, however during the downturn cycles, most recently since 2012, graduates exiting from the discipline can find employment difficult and this contributes to reduced enrolments in subsequent years. From an AusIMM (Australasian Institute of Mining and Metallurgy) members’ employment survey conducted in 2013, more than half of the graduates exiting from disciplines related to mining and minerals were not confident of finding employment (AusIMM, 2013). In the long term the concern is not only how to sustain enrolment and graduate numbers but also to provide the opportunity for students to acquire the professional skills that they require to make them attractive to industry.Maintaining and sustaining core competencies in the minerals discipline is an ongoing challenge. There have been a number of recent papers on this issue presented at international conferences (e.g. McCaffrey et al, 2014; Drinkwater and Napier-Munn, 2014) and there is general agreement that one of the ways in which the deficit in foundation concepts can be addressed is through workplace development. Drinkwater and Napier-Munn (2014) presented data from a survey of industry professionals that indicated that more than 90% of respondents undertook on average 30 days of training each year of which approximately 5 days was professional short courses."

Jan 1, 2016

By C. V. Deutsch, O. Babak, J. G. Manchuk

High levels of geological heterogeneity occurring over relatively short distances pose a challenge to the unconventional open-pit techniques used in oil sands mining. There is strong motivation to mine selectively and minimize dilution and loss; however, the large equipment and high mining rate used to meet production targets tend to reduce selectivity. A numerical model is developed to account for geological complexity, mining equipment, regulatory criteria, and other operational parameters. This framework is used for more accurate forecasts, optimization of equipment, and other operational decisions. An example demonstrates the approach in light of Alberta Energy Regulator criteria.

Jan 1, 2014

By Charlie Graham

Our Approach ? Industry Trends ? New Forces at Work in Mining ? Deep Mining ? Energy projects ? Air power ? Hydraulics ? Electric alternatives ? Drilling ? Productivity ? Conclusions ? Transportation ? References

Oct 1, 2010

By Mohan R. Srivastava

- OUTLINE - apologies and explanations - a quick bit of history - the wisdom of Wikipedia - ?Matheronian geostatistics continued to convert Bre-X?s bogus grades and Busang?s barren rock into a massive phantom gold resource?? - variogram analysis for Busang - would variogram analysis (or variance analysis) have revealed the fraud? - what went right, what went wrong

May 1, 2007

By J. H. Reiss, D. F. Bruhn, Idaho National Laboratory, Y. Jiao, D. W. Reed, Y. Fujita, D. L. Daubaras

"Bioleaching offers a potential approach for recovery of rare earth elements (REE) from recyclable materials, such as fluorescent lamp phosphors or degraded industrial catalysts. Microorganisms were enriched from REE-containing ores and recyclable materials with the goal of identifying strains capable of extracting REE from solid materials. Over 100 heterotrophic microorganisms were isolated and screened for their ability to produce organic acids capable of leaching REE. The ten most promising isolates were most closely related to Pseudomonas, Acinetobacter and Talaromyces. Of the acids produced, gluconic acid appeared to be the most effective at leaching REE (yttrium, lanthanum, cerium, europium, and terbium) from retorted phosphor powders (RPP), fluidized cracking catalyst (FCC), and europium-doped yttrium oxide (YOEu). The Acinetobacter isolate, BH1, was the most capable strain and able to leach 33% of the total REE content from the FCC material. These results support the continuing evaluation of gluconic acid-producing microbes for large-scale REE recovery from recyclable materials.INTRODUCTIONAn enhanced recovery, substitute, reuse or recycle paradigm is important for balancing the supply and demand of critical materials (DOE, 2011). The recovery of rare earth elements (REE) from recyclable materials is an important component in this model. REE are used in a variety of modern products. For example, neodymium, europium, terbium, dysprosium, and yttrium are important for applications such as permanent magnets, lamp phosphors, rechargeable batteries, etc. (Binnemans, Jones, Blanpain, Van Gerven, Yang, Walton, & Buchert, 2013; DOE, 2011; Graedel, Harper, Nassar, & Reck, 2013). Cerium and lanthanum are used in glass polishers and additives in fluidized cracking catalysts (FCC)."

Jan 1, 2016

By O. A. Ojo, N. Esmaeili

"The effects of brazing and use of composite powder mixture as interlayer material on hot corrosion resistance of brazed IN738 superalloy were studied. Brazing was observed to result in significant reduction in the hot corrosion resistance of the superalloy. However, application of composite powder mixture, which consists of additive superalloy powder, enhanced the hot corrosion resistance of brazed samples. It is also found that although the use of composite powder mixture increased hot corrosion resistance of brazed alloy, if the additive powder completely melts, which is possible during brazing, it can significantly reduce the hot corrosion resistance of the brazed joint. Elemental micro-segregation during solidification of the joint with completely melted powder mixture produces chromium depleted zones and consequently reduces hot corrosion resistance, since a uniform distribution and adequate chromium concentration is necessary to combat hot corrosion. This has not been previously reported in the literature and it is crucial to the use of composite powder mixture for enhancing the properties of brazed superalloys.INTRODUCTION Superalloys have been developed in response to the increasing demand for materials with higher resistance to corrosion and creep and also with higher mechanical strength at higher temperatures (Smith, 1981). Ni-base superalloys are predominantly used in manufacturing hot sections of gas turbine engine components. This is due to their high strength and corrosion resistance in extremely high temperature service environments which is typical for hot sections of gas turbine engines (Miglietti, 2009). The continuous demand for higher efficiency and output has resulted in the use of higher operating temperatures and gas pressure in modern gas turbine engines (Jahnke & Demny, 1983). Consequently, this has caused thermal and mechanical stresses which result in severe degradation and damage of gas turbine engine components due to creep, fatigue and hot corrosion (Zhang, Feng, & He, 2006). The decision to replace or repair damaged parts depends on the overall repair cost and expected life of the repaired components (Jahnke & Demny, 1983). However, in most cases, it is more cost effective to repair damaged parts rather than use a full replacement."

Jan 1, 2017

By Neillm Alastair S.

"This paper looks at what has happened in the past decade in the rare earth industry, particularly for those companies outside China trying to develop alternative projects to the Chinese dominated supply chain. The rare earth industry has gone through a metamorphosis over the past decade. The industry was basically unknown outside China until overnight it became the next hot topic on the financial streets of Canada and Australia. Suddenly various junior miners shifted from uranium and other out-of-favor commodities to rare earths as funds were easy to access from an investment community that did not understand the complexities of the space. The initial funding was done on traditional junior mining metrics of grade and deposit size. This has morphed over time to:1) Lights versus heavies2) Making a concentrate3) The importance of separation4) Off-take agreementsAt the peak of the market frenzy certain flagship operations were built using the “Not Made in China” moniker. Unfortunately certain errors were made during implementation, which are finally coming to the surface and making the rest of the pack wondering what will happen next. A review and update of some of the mistakes made and lessons learned will be discussed.BACKGROUNDAbout ten years ago awareness started to form around the rare earth industry and various groups recognized that because of the closure of Molycorp, Mountain Pass, and the dominance of China, there was a risk of uncertainty of reliable supply. This was not news for those active in the industry like Rhodia (now Solvay), the Japanese, South Koreans and other key consumers but to others it was like a light went on and rare earths became the new “.com” trend for investment banks, investors and some mining companies looking for the next hot topic.In the late 1990’s Molycorp accounted for around 20-25% of the world’s supply of rare earths, mostly lights (La, Ce, Pr and Nd), with small amounts of heavies from other sources. Then environmental issues forced the closure of the operation at Mountain Pass. Within six months China had increased production to plug the gap in supply. Around that time China was developing a strategy to leverage their position in rare earths and implemented a series of regulations to increase the value added component of rare earths inside China."

Jan 1, 2016

By W. Hawker, A. M. Ivana

"Pressure oxidation is used to liberate gold from refractory sulphide ore and concentrates with over fifteen autoclaves in operation. Despite the importance of pressure oxidation, the autoclave chemistry and chemical thermodynamics are not well established. For example, there is no consensus on aqueous iron speciation or stability of jarosite phases. Additionally, there remains questions about basic ferric sulphate formation and stability. In addition to a review of the current state of knowledge, a methodology to study the ferric precipitation reaction and relate the results to chemical thermodynamic predictions is presented which will be used to accurately define the phase boundaries of the iron precipitates in the future (hematite, jarosite and basic ferric sulphate).INTRODUCTION With declining availability of orebodies that respond to simple leaching conditions, pressure oxidation has become a prevalent technology to liberate gold locked in sulphide mineral matrices. Gold pressure oxidation was established 32 years ago, with McLaughlin being the first facility in 1985 (Thomas & Pearson, 2016). Pressure oxidation is carried out at elevated temperatures ranging from 180 to 240°C as shown in the summary of operations in Table 1 (Ruonala et al., 2016; Fleming, 2010).A considerable amount of research has been done to study iron solubility and precipitation under autoclave conditions (Tozawa & Sasaki, 1986; Umetsu et al., 1977; Sasaki et al., 1993; Fleuriault, 2016; Cheng & Demopoulos, 2004; Papangelakis et al., 1994; Yue et al., 2003). These reports provide a description of the process chemistry and iron behaviour in the autoclave. However, there remain questions about the type and stability of aqueous species and solid phases. This detailed information is required to build a robust chemical thermodynamic model of the system, allowing for equilibrium and kinetic reaction limitations to be discerned."

Jan 1, 2017

As land resources decrease, commodity prices increase, and technology evolves, deep sea mining is becoming a viable alternative to meet the increasing demand for minerals. Successful deep sea mining operations are built on sound identification of the resource, proper selection of equipment, a thoughtful production plan, and good project management. These four key activities can be further optimized by analyzing how the spatial variability and uncertainty of the ore body properties impact the final mining operation. To address this problem, IHC Merwede is in the process of developing a risk quantification framework in the context of deep sea mining, which makes use of state of the art geostatistical simulation methods and transfer functions to quantify geological uncertainty and translate it into decision or project risk. The paper introduces the Local Average Subdivision method (LAS) for generating simulated models of the deposit and presents a new extension to incorporate point measurements of geotechnical or ore grade properties. Due to its computational efficiency, the presented method is suitable for simulating largely extended sea floor deposits. The second part of the paper illustrates, through example case studies, the significant benefits of a risk based approach which translates geological uncertainty into financial or operational performance indicators. In particular, the focus is on assessing financial project risk and on the design optimization of the deep sea excavation equipment by analyzing cutting forces, specific energies, and power requirements.

Aug 1, 2013

By V. Panayotov, M. Panayotova

"Finding a reliable relationship between fundamental properties of minerals of non-ferrous metals and their ability to float is extremely important. The approach presented in this work allows us to draw predictive models for an effective flotation, suitable choice of reagents regime and expected technological results before the minerals enter the flotation process. Attempts to adjust the technological regime in already begun flotation are often unsuccessful because the basic physicochemical processes have already taken place. Mineral processing can be optimized on the basis of objective and basic parameters, decisive for the efficiency of the process - the state of the surface of the mineral; assessment of: minerals flotation ability, the need to apply and the type of needed pretreatment, and expected technological results. The theoretical foundations of such an approach are presented in the work, as well as supporting them experimental results, and information on practical implementation in lead-zinc and copper-pyrite ores selection.INTRODUCTIONIncreasing impoverishment of ores of nonferrous metals incoming to the flotation and rising costs for obtaining the final product lead to the inevitable question - will the mineral processing process be beneficial economically, technologically feasible and environmentally safe and what is the way to improve its efficiency. Some of the possible solutions are already in practice - new more efficient and less energy consuming flotation machines and equipment, new - more efficient and selective reagents, new combinations of flotation regimens, and so on.Finding a reliable relationship between fundamental properties of minerals of non-ferrous metals (sulphides and oxides - most of them with semiconductor properties) and their ability to float is extremely important. This is the subject of research, started in the 60s of the previous century and continuing to the present day. Such dependence would enable a realistic assessment of flotation ability (flotability) of minerals before their flotation processing. The basic dependence, displayed by the researchers as Hoberg (1975), Chanturia and Shafeev (1977), Chanturia and Lunin (1983), etc., represents a relationship between bulk properties of minerals and their flotability, considering especially the concentration of the main charge carriers, namely electrons or holes. The bulk properties are practically constant for minerals from a given field. But the 'main arena' of the flotation process is actually the mineral surface (Carta, 1970; Rao, Labonte, & Finch, 1992; Panayotov, 1999; Rao, 2003; Hu, Sun & Wang, 2010). Therefore, we introduce a methodology for studying the surface of minerals, which methodology gives the degree of semiconductor bands bending on the surface and respectively - the charge of the mineral surface and its ability to interact with reagent-collector. The latter can be used to select the most optimal reagent for the corresponding mineral."

Jan 1, 2016