Search Documents

"Real-time, on-stream analysis of the metal content of process slurries is an essential prerequisite for process monitoring and advanced control of mineral processing circuits. On-stream X-Ray Fluorescence (XRF) sensors for base metal applications are available commercially and form the basis of many plant monitoring circuits. To date, these commercial technologies have been insufficiently sensitive to measure precious metals such as gold and platinum group elements, typically present at part-per-million (ppm) and sub ppm levels. CSIRO has developed a novel X-ray based technology, called UltraGold, which enables detection of gold in slurries on a real-time basis with a precision below 100 parts-per-billion. This technology is based on the use of advanced X-ray optics, extensive Monte Carlo computer modelling for analyser design, high accuracy X-ray spectrum fitting where the X-ray intensities are matrix corrected. In this paper, we will introduce this technology and discuss the results of a proof of principle study performed in the laboratory with plant slurries (tailings and concentrate) from an Australian beneficiation plant. Finally, we will discuss further planned improvements. As projected grades in (gold) mining around the world fall and several large-scale mines approach the limits of their economic reserves, this method can enable significantly reduced operating costs by rapid analysis to improve circuit efficiency and hence improve recovery significantly.INTRODUCTION This paper describes a study undertaken to explore the feasibility of applying CSIRO?s UltraGold XRF technology to the on-stream measurement of gold in process slurries. The provision of rapid, accurate information of gold grade in feed, tailings and concentrate streams would facilitate significantly improved process control and early detection of plant upsets, resulting in substantial cost-savings. CSIRO have patented X-ray fluorescence (XRF) techniques for the analysis of key elements in slurries present at part-per-million (ppm) and sub-ppm levels. Conventional, commercially available on-stream XRF instruments generally have detection limits in the tens of ppm range, precluding their use for analysis of elements like gold that are mined and processed at much lower concentrations."

Jan 1, 2017

By Neil Westoll

But First, An Overview of the Selwyn Basin and Its Resources ?World-renowned sedimentary-exhalative (SEDEX) deposits of zinc, lead, silver +/-barite ?Significant reserves/resources remain and vast tracts of prospective stratigraphyremain under-explored and untested. ?More details are at the Yukon Geological Survey?s Selwyn Basin Metallogenysite:http://www.geology.gov.yk.ca/metallogeny/selwyn/ Overview of Metal Price and Demand Trends ?The pace of economic change in China has been extremely rapid since the start of economic reforms just over 25 years ago. According to official statistics, economic growth has averaged 9.5% over the past two decades and seems likely to continue at that pace for some time. National income has been doubling every eight years. Such an increase in output represents one of the most sustained and rapid economic transformations seen in the world economy in the past 50 years.? Organization for Economic Co-operation and Development 16-Dec-2005

May 1, 2006

By Bennett McLaughlin

AGNICO-EAGLE started sinking the Penna Shaft in 1995 with a hoisting plant capable of hoisting 1,800 tonnes per day from a 2,240 metre deep shaft. Exploration success lead to the installation of a hoisting plant capable of extracting 4,500 tonnes of ore and 1,800 tonnes of waste per day from a depth of 2,210 metres. The introduction of a new rope selection factor, permitting a safety factor of 4.0, represented the breakthrough required for a cost-effective project. This paper describes the process taken to introduce the new rope selection factor and its impact on the original plant.

May 1, 2001

By H. B. Sahu, N. M. Mishra, D. C. Panigrahi

The paper presents the development of a spontaneous heating liability index (SHLI) of coal based on a mathematical approach. The parameters for the calculation of this index have been determined by differential scanning calorimetric studies. Thirty-one coal samples representing both fiery and non-fiery coal seams of different ranks have been collected from different Indian coalfields and their SHLI values have been determined. In addition, the susceptibility of these samples to spontaneous combustion has been ascertained by standard crossing-point temperature measurement. The moisture percentage of all the samples has been obtained by proximate analysis. A comparative study between SHLI and crossing-point temperature, along with moisture percentage, indicates that SHLI predicts the proneness of coal to spontaneous heating more accurately.

Jan 1, 2008

By D. R. Jolley

"The selection of equipment for open-pit mining is an important decision which results in a considerable capital expenditure by the operator. The decision is complicated by the wide product range on the market. Certainly, equipment performance is an important criterion to consider in making the decision. Equally important, however, is the operating inter-relationship among the equipment. A poor balance increases production costs and waiting time as queues form at the bottlenecks. This inter-relationship is dependent on equipment performance, but it is also affected by management decisions (i.e. scheduling techniques).The purpose of this paper is to show how the computer is used to decide which equipment and operating decisions achieve the required production objectives at least cost. Actual mining of the pit is simulated over a period of time using different equipment and scheduling decisions. Production, waiting time and costs are evaluated for each alternative until the operator is satisfied that he has achieved the best result."

Jan 1, 1970

By J. F. Wright

Gold-bearing quartz veins and replacement chalcopyrite deposits are the two important types of metallic mineral deposits of the east central Manitoba mining district. The gold-bearing veins occur along Manigotagan valley, northwest for 25 miles from Beresford lake, and the copper deposits along Oiseau valley, between Oiseau lake and the east end of Lac du Bonnet. Lithium-bearing minerals of possible commercial value have recently been discovered in pegmatite along Winnipeg river about 10 miles east of Point du Bois. There are also prospect pits with showings of galena, sphalerite, cobaltite, pentlandite, nickeliferous pyrrhotite, arsenopyrite, pyrite, molybdenite, cassiterite, and other minerals, but the various occurrences of these minerals, as exposed, are small. The bedrock and mineral deposits of this mining district are Precambrian and resemble in many respects the formations and mip.eral occurrences of western and northern Ontario. Although prospectors visited eastern Manitoba at intervals during the last fifty years, effective prospecting did not begin until 1913 or 1914, and not until 1923 were skilfully directed, systematic explorations undertaken. It is true, that between 1913 and 1923 considerable sums were expended in a number of attempts at mining and milling the gold-quartz ore, but these enterprises failed partly through poor management or attempts to develop veins that were too small or too low-grade to be worked at a profit under the existing conditions of transportation and power supply.

Jan 1, 1925

By Michael L. Free

The hydrometallurgy curriculum for undergraduate students at the University of Utah has evolved to contain a variety of tools to help students understand and apply hydrometallurgy in a context that has industrial relevance. In order for students to perform as engineers in an industrial hydrometallurgy setting, they need to understand thermodynamic and kinetic fundamentals and be able to apply these fundamentals to extraction, concentration, and recovery applications. Students must also understand related environmental, economic, and assessment issues in hydrometallurgy and be able to work with others. In order to meet these needs, the hydrometallurgy curriculum includes a variety of relevant subject information, on-line resources, laboratory experiences, and team work opportunities to help prepare students for careers involving hydrometallurgy. The development and use of these resources will be discussed in this paper.

Jan 1, 2014

By David J. Forrester

"CANMET’s research into underground coal mining is primarily conducted at the Cape Breton Coal Research Laboratory (CBCRL), established in 1981 to conduct safety research in underground coal mines. Located close to Canada’s largest underground coal producer, in the Sydney Coalfield of Nova Scotia, CBCRL’s program also includes the two western underground coal operations. CBCRL is a relatively small laboratory with a staff of thirteen — eight professionals and five support staff — with an annual budget of over $1 million. In order to maintain effective research response, flexibility is key and staff are increasingly working in project teams, crossing traditional section ties and also drawing from specialist expertise elsewhere within CANMET.CBCRL’s research activities have had a substantial impact on the Canadian underground coal mining industry, particularly in Cape Breton. CBCRL contributed to Cape Breton Development Corporation’s (CBDC’s) threefold reduction in lost-time accidents in the 1980s. Also, in the last four years alone, CBCRL’s work has enabled CBDC to save over $17 million in improved utilisation of reserves and cost savings. The work embraces the three traditional areas of mine environment, strata mechanics and mining technologies, however the current direction has been strongly influenced by recent external and internal factors. It is timely to review progress and recent directions."

Jan 1, 1996

By N. Shi, T. G. Joseph

The design of dippers for cable shovels has essentially remained unchanged for the last 100 years. In the past 10 years, shovel manufacturers have started taking another look at dipper design, resulting in changes that have borne models from major manufacturers that address some of the wear conditions and material retention problems that dominate maintenance and operational costs. However, with the exception of added lateral curvatures to the front and corners of the dipper, the geometry is essentially unchanged. This paper looks at the criteria that have resulted in the first new cutting dipper design in a century. The design is based on kinematic considerations, reflected in a revolutionary geometry that matches the range of motions of the shovel, designed to minimize wear, impact loading and power required to dig, thus maximizing productivity for a minimum energy requirement. The shape configuration is such that the weight of the dipper is reduced through wall thickness, enabling a larger capacity dipper to be conceived for the same shovel. Benefits are reflected in reduced operational and maintenance costs and increased productivity.

Jan 1, 2006

By W. S. McDonald

PRACTICALLY all dusts derived from organic matter are explosive and instances are recorded of explosions-some of them extremely violent-having occurred in grain elevators and flour mills. While a discussion of the explosibility of dusts in general, doubtless, would be of more than academic value, it will be of greater interest, on this occasion, to consider various phases of the problems connected with the hazards arising from coal dust. Extensive and valuable research has been carried out during the past few decades on the subject of coal-dust explosions and a great part of this work has been concerned with the preventive effect of stone or other incombustible dusts. Four men have been outstanding in this very substantial achievement. The first is Dr. W. Galloway, who succeeded in demonstrating by experiments that one pound of coal dust mixed with 150 cu. ft. of air formed an explosive mixture. The next is Sir W. Garforth, who proved that stone dust is an effective preventive for coal-dust explosion. The third is G. Haon, and last but not least, L. G. Hill, both of whom laboured incessantly to produce a suitable stone-dust and a satisfactory method of application. Today, mining men all over the world are satisfied and convinced that stone dust, if properly applied, will prove effective in greatly minimizing, if not completely preventing, explosions of coal dust, as has been demonstrated in experimental mines, as well as in actual explosions, in practically every coal mining industry.

Jan 1, 1938

By W. A. Padgham, H. Helmstaedt

Field evidence for current hypothe e about age and kinematic ignificance of gold-bearing hear zones in the Archean Yellowkni fe greenstone belt is reviewed , and it is concluded that major disagreements between previous workers are a direct result of differences in stratigraphic and tructural in terpretations of the Yellowknife Supergroup. Although goldbearing hear zone appear to be confined to the mafic volcanic pile of the Kam Group. it can be shown that shearing affected all supracru tal rocks, including the Jackson Lake Formation. now con idered to represent the youngest unit of the Yellowknife Supergroup. tructural ob ervations are incompatible with the hypothe is that the hear zones represent loci of ynvolcanic gravity sliding but are consistent with earlier conclu ions that shear zone development commenced with rotation of the volcanic pile and continued as re ult of lateral shortening broadly overlapping with the emplacement of granitoid batholiths. Shear Zones are common throughout the entire green tone belt. yet productive zone are confined to the Yellowknife Bay Formation of the Kam Group and localized where flow abut with a high angle again t the contact of the We tern Plutonic complex. However. no obvious tructural and lithological features have been recognized that are more favorable for gold deposition and distinguish the shear zones and flows of the area around the mines from those of other parts of the greenstone belt. The model that gold wa transported by metamorphic solutions and that hear zones were the firs t-order control for gold deposition provides no explanation for the trong localization of the depo it . As porphyries with elevated gold contents are present in and near ome of the mines. the possibility that gold was deposited from hydrothermal system around fel ic intrusion representing early phases of the Western Plutonic complex should be given erious consideration.

Jan 1, 1986

By Dave Stefanuto

Voisey?s Bay Project Components ? Mine/Mill Port In Labrador ? Mini Plant in Mississauga ? Demonstration Plant in Argentia ? Supply Vessel (Umiak1) ? Transshipment Facility (Quebec) ? Concentrate Handling & Transport to Sudbury/Thompson ? Cobalt Refinery Upgrade (Thompson) Project Setting ? The Project is on the traditional lands of the Labrador Inuit and the Labrador Innu ? Canadian courts have held that Aboriginal peoples in Canada possess special rights to traditional Aboriginal lands Those rights can include requiring resource developers to enter into Impacts and Benefits Agreements (IBAs) on traditional lands to set forth how lands can be used and benefits to be received by Aboriginal people

May 1, 2006

By J. A. Finch, A. R. Laplante, R. Espinosa-Gomez

"The Niobec concentrator rejects up to /5% of the Nb as slimes (-10u.m). The recovery of Nb from these slimes by column flotation is being studied. An essential condition for selective flotation is slimes dispersion. A particle size analyzer, the Sedigraph 5000D, was used to monitor dispersion in plant waters with combinations of organic and inorganic dispersants and flotation reagents. Flotation reagents were particularly detrimental to dispersion with sodium silicate. The best dispersion conditions were selected for column flotation tests. These tests revealed that reagent combination had a pronounced effect on froth stability. Careful frother selection achieved good froth stability under conditions of good dispersion. Plant water increased the required dispersant concentration causing mineral depression.IntroductionSlimes (-10 u.m) rejected at Niobec contain up to 15070 of the over-all Nb content . Recovery of Nb from these slimes would significantly increase over-all recovery. A suggested recovery route involves two phases: (1) carbonate flotation (to remove most of the carbonates) depressing silicates and pyrochlore (as currently done at Niobec); and (2) selective (direct) pyrochlore flotation from the silicates. Phase 2 has been addressed and several routes to achieve selective flotation are available. Phase I was attempted with the selective reagent scheme used at Niobec but a considerable amount of pyrochlore floated with the carbonates due to poor slimes dispersion."

Jan 1, 1987

By Lawrence Devon Smith

"What is Due Diligence?Within the mining industry the term “due diligence” is used to describe a detailed data review, generally in connection with the purchase or sale of a mineral property, the approval of a large capital expenditure, or the borrowing of a large sum of money.The term originates in the requirement of the board of directors of a corporation to “act honestly and in good faith ... and exercise the care, diligence, and skill that a reasonably prudent person would exercise in comparable circumstances” (OBCA, 1994). Furthermore, the law assumes that a corporation (or its board) will have exercised due diligence in the acquisition of an asset and, therefore, knowingly (in the absence of fraud or deceit) will have taken on the liabilities and obligations associated with the asset (Nelson, 1994). This is the familiar “Buyer Beware”.Directors are liable for their decisions except “if the director relies in good faith upon financial statements of the corporation represented … by an officer of the corporation or in a written report of the auditor, or a report of a lawyer, accountant, engineer, appraiser, or other person whose profession lends credibility to a statement made by any such person.” (OBCA, 1994).Hence the importance of reports prepared by professionals. They provide confirmation that the directors have exercised due diligence in the performance of their duties. For this reason these reports are referred to as due diligence studies"

Jan 1, 1997

By Lawrence Devon Smith

"Within the mining industry the term “due diligence” is used to describe a detailed data review, generally in connection with the purchase or sale of a mineral property, the approval of a large capital expenditure, or the borrowing of a large sum of money.The term originates in the requirement of the board of directors of a corporation to “act honestly and in good faith and exercise the care, diligence, and skill that a reasonably prudent person would exercise in comparable circumstances” (OBCA, 1994). Furthermore, the law assumes that a corporation (or its board) will have exercised due diligence in the acquisition of an asset and, therefore, knowingly (in the absence of fraud or deceit) will have taken on the liabilities and obligations associated with the asset (Nelson, 1994). This is the familiar “Buyer Beware”.Directors are liable for their decisions except “if the director relies in good faith up on financial statements of the corporation represented by an officer of the corporation or in a written report of the auditor, or a report of a lawyer, accountant, engineer, appraiser, or other person whose profession lends credibility to a statement made by any such person.”(OBCA, 1994).Hence the importance of reports prepared by professionals. They provide confirmation that the directors have exercised due diligence in the performance of their duties. For this reason these reports are referred to as due diligence studies."

Jan 1, 1996

By Benjamin H. Clark

"For over 50 years, Derrick Corporation has been renowned for its innovative and durable fine screening equipment and screen surface technology. Derrick’s latest innovation, the patented Stack Sizer, offers mineral processors both high tonnage capacity and high separation efficiency on an extremely small footprint.The Stack Sizer is suitable for separations from 6.3 mm down to 75 microns (200 mesh). The Stack Sizer, coupled with Derrick’s patented urethane screen surface technology, offers an extremely economical alternative to hydraulic classifiers, hydrocyclones, and less efficient low volume wet screening systems. Stack Sizers have been used in feed preparation for flotation, spirals, and a variety of jigs. Mineral processors wishing to reduce grinding circuit circulating loads and generation of slimes due to over grinding, thereby enhancing the efficiency of flotation and gravity circuits, now have another technology at their disposal to perform this critical sizing and grade control function.Over 200 Stack Sizers have been installed in numerous mineral processing applications worldwide attesting to the rapid acceptance of this technology. Stack Sizers are currently screening ferrous and non-ferrous metal ores, mineral sands, silica sand, kaolin clay, feldspar, garnet, phosphate, aluminum dross, potash, coal, tantalum, spodumene, niobium, and other rare earth mineral ores.INTRODUCTIONDerrick engineers have long understood and demonstrated the importance of screen width in coupling both high capacity and high separation efficiency for fine wet sizing applications. As opposed to fine dry sizing, where the length of the screening machine is critical for high separation efficiency, introducing slurry feed to screens in a thin and even layer at minimal velocities across wider screen surfaces allows for high capacities and efficiencies, with maximum screen cloth life. This is due primarily to the combination of free liquid and high frequency vibration of the Derrick motors, which allow fine undersize material to pass through the screen apertures. Lacking either of these factors would be extremely detrimental to the screening process. Without the high frequency vibration of the motor, the screen is essentially a low efficiency sieve bend. Without the free liquid to carry fines through the screen openings, the screen is for all intents and purposes a glorified conveyor or dewatering unit, as little or no sizing takes place once the screen is devoid of free liquid. For optimal screening results, Derrick recommends feeding slurry to a screen at approximately 20% solids by volume. Figure 1 shows the Stack Sizer design concept. Note that a single feed point is used to evenly distribute the flow to the five separate feed points."

Jan 1, 2007

By John Lindsay

Outline ??Recovery plant requirements and concepts ??Common recovery plant unit processes ??Recovery plant design considerations ??Peripheral issues Process Design ??Liberation ??Separation ??Recovery Processing ??Density 3.5 g/cm3 ??Luminescent under x-ray ??Hydrophobic (non wettable) surface ??Non-magnetic ??Inert to strong acids / bases

Apr 1, 2005

By H. H. Gardner

INTRODUCTION THE problem of mechanization is one of the most vital in the minds of Alberta coal operators today. In these times of constantly increasing operating costs, any way of decreasing the cost of a ton of coal must be explored to the limit. There seems no better field for such effort than the successful application of power to the mining and loading of coal. We are fortunate in having neighbours to the south who have made .remarkable progress in recent times along these lines. Higher tonnages per man have resulted in higher wages to the employee and lower cost to the employer. It might seem that our problems could be solved merely by imitating our neighbours. Unfortunately, neither practice nor experience substantiate this conclusion. It is with the purpose of reviewing our accomplishments, as compared with practice in the United States, and at the request of the Prgoramme Committee for this meeting, that this paper is written. The Committee believes that such a general discussion and comparison may well lead to further advances in our mining methods. SUMMARY OF PRACTICE IN THE UNITED STATES A visit to the highly mechanized coal mines of the United States is always most instructive and encouraging.

Jan 1, 1951

By S. G. Shabestari

Thermal analysis is a tool that is generally employed to predict the structure of the alloy before the actual casting is carried out. By cooling a sample of the molten alloy and recording the temperature-time curve, important solidification events may be analyzed by using the first derivative-cooling curve. In this research, strontium is added to (AS5U3G) 319 aluminum alloy and its influence on the formation of intermetallic compounds e.g. Al15(Mn,Fe)3Si2, Al2Cu, Al5Mg8Cu2Si6 formed during pre- and post-eutectic reaction have been investigated. Also any changes in solidification parameters such as temperature of Al-Si eutectic under cooling and temperatures of nucleation and growth of each phases caused by strontium addition, have been determined via the first derivative cooling curves. The effect of strontium on the formation of various intermetallic compounds has been studied by using very accurate thermal analysis equipment and the microstructures were analyzed using an optical microscope. The various phases reported in this paper were identified using Scanning Electron Microscopy (SEM) and linked to Energy Dispersive Spectroscopy (EDS). Formation of all pre- and post-eutectic phases was interpreted by comparing the phases formed in the microstructure and the reactions detected by using cooling curves. The results of this research indicate that thermal analysis technique can be used as an on-line process control in the production lines in aluminum casting industries.

Jan 1, 2004

By R. K. Jonas

"Pressure leaching and pressure oxidation in autoclaves are important alternatives in the extractive processing of gold, copper and nickel ores. The application of advanced control to pressure leach and pressure oxidation autoclaves could achieve significant benefits as has been shown in alumina pressure leaching. This paper compares and contrasts alumina digestion autoclaves to other mining autoclaves with respect to advanced controls. The application of advanced control in alumina with over 30 units controlled worldwide, and its benefits will be reviewed. The design and potential benefits from advanced control for pressure oxidation and leaching will be presented.INTRODUCTIONIt is this author's position and the purpose of this paper to propose that advanced control could be effectively applied to autoclaves in the nickel, gold, and copper mining processes. This is based on the proven effectiveness of advanced control on autoclaves used in the alumina industry for pressure leaching of bauxite ores. Incremental, but significant increases in production could be realized by applying advanced control to autoclaves, as evidenced by the alumina industry, and this not being implemented in other autoclaves in the mining industry.In addition, today the mining industry is being challenged to improve their production methods. In some markets like nickel, there is pressure to improve productivity and reduce the cash cost per ton. While in other markets like copper and gold, demand is vigorous with favourable pricing, and there are advantages to increase production and productivity given limited plant capacity. Advanced control has proven its capability to improve mineral processing operations through increases in throughput, recovery, as well as reducing variability. In today's mines, autoclaves are being used to a much larger scale and with much larger importance, thus it would be beneficial to improve operational performance through the use of advanced control.Accordingly, it is the author supposition that an opportunity exists in the mining industry to use a proven advanced control technology to improve the operations and financial performance of mines using autoclaves."

Jan 1, 2012