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By F. G. Smith

Abstract Laboratory methods are now in use whereby the temperature and pressure during the crystallization of hydrothermal minerals can be determined. The techniques include the use of the decrepitation method of studying liquid inclusions, and electrical measurements of pyrite. The determinations are sufficiently accurate that the data can be used in solving a variety of ore deposition problems. Within the last year, several new laboratory techniques have been developed in the Geochemical Laboratory of the Department of Geological Sciences, University of Toronto. The results of several tests of ore by these methods have proved to be useful in treating some problems which previously were considered unsolvable. It is now possible to determine the temperature of deposition of most of the minerals in a hydrothermal ore deposit, also the depth below the surface during deposition. Measurements can also be made of the reopening history of a complex ore. The temperature-pressure determinations depend upon the fact that minerals deposited from a hydrothermal solution always trap a small amount of the solution at the time of crystallization. The solution, being predominantly composed of water, has a density which depends upon the temperature and the pressure prevailing during crystallization. After ore deposition is complete, erosion and isostatic uplift finally exhumes the vein. During this slow fall in temperature and pressure, the solution contracts and a gas bubble appears. If the trapped solution in the mineral is examined, the gas-liquid ratio records the density of the solution at the time the mineral was deposited (except for a slight change in the volume of the mineral). The thermal expansion and compressibility of water and water solutions are known to a sufficient degree that, if the gas /liquid ratio can be determined, the temperature-pressure relations during deposition can be calculated.

Jan 1, 1949

By Keith C. Hendrick

"Metal prices are frequently the most critical and least predictable element in determining the profitability of mining operations. Short -term fluctuations can be offset in varying degrees by hedging or other market actions. Such solutions are not practical for the longer term, The paper investigates the nature and extent of metal price risks and evaluates methods to reduce them.IntroductionIt is management's responsibility to improve the odds by managing the-risks by identifying them clearly, assessing them accurately, minimizing them where possible-and, then, timing decision s success fully.In determining the profitability of current operations, preparing forward plan s or developing feasibility studies for new projects or expansions, pr ices are usually the most critical input. Being market determined rather than cost based, they can also be the most unpredictable As a result, commodity prices are frequently the greatest of all risk factors.Nature of Commodity PricesThe cyclical nature of commodity prices is well known. They are stable only when supply is in balance with demand and forecast to remain that way. An imbalance on either side of the equation can lead to a price reaction completely out of proportion to the actual or perceived surplus or shortage.This exaggeration arises through the cumulative effect of market forces. When the market senses an uptrend, consumers buy for the expected increase in activity. They also seek additional quantities for inventory before price s rise. Merchants defer spot sales anticipating higher price s, speculators go along for the same reason, and producers raise prices in response to demand. Events tend to confirm the expectation of each party and strengthen their reaction causing prices to move higher."

Jan 1, 1983

By J. E. Dutrizac, R. J. C. MacDonald, J. B. O'Reilly

"Sometime around 3000 B.C., primitive metallurgists working in the mountainous regions of Asia Minor bordering on the Black Sea (Pontus) produced a soft, easily fused metal today known as lead. It appears certain that the first metal was made by reductive smelting of galena, but whether this recovery arose by the accidental inclusion of galena in the stones of a fire hearth or whether it occurred as a consequence of simple pyrometallurgical experiments on a series of interesting ""stones"" will likely never be known with certainty. The properties of galena, high metallic lustre, great density and facile cleavage, must have excited the ancients, and such ""stones"" would have been the object of primitive testing111 - Shortly after the discovery of lead, the ancients found that the controlled oxidation of this metal at elevated temperatures yielded smaller amounts of a more interesting material, silver. Again, it is uncertain if the production of silver by primitive cupellation techniques was the result of a fireside accident or the consequence of a deliberate experiment, but the important fact is that silver was produced shortly after the discovery of lead. The techniques for making lead and silver spread gradually throughout the entire civilized world, likely as a result of both technology diffusion and independent rediscovery. The physical properties of lead could not have been overly attractive to the ancients, but silver was a different matter altogether. The gleaming white lustre and relative immunity to oxidation quickly assigned silver to the precious materials category, a status it still enjoys. In early times, argentiferous galena was inevitably processed only for its silver values; lead was generally an unwanted byproduct and was frequently discarded as litharge (PbO) during the cupellation process. The silver was eagerly sought, however, and resulted in considerable mining activity culminating in the famous Athenian silver mines at Laurium at the southern end of the Athenian peninsula."

Jan 1, 1999

By José J. Suárez

As pressure grows for commodity pricing, new mines are more difficult to develop, the stock markets demand better financial returns from mining companies, resources for the developing and operations are scarce, and developing countries in Asia, and Africa demand more metals, it is important that mining companies effect better utilization of capital to develop capital projects. In the last few years, the costs for Capital projects have been impacted by the following factors:

May 1, 2013

By M. Wu, G. Plascencia, A. E. M. Warner, A. Vahed, T. A. Utigard

Nickel oxide granules formed by pyrohydrolysis of a chloride solution, were reduced in hydrogen. Below 400 °C, an incubation period was observed, followed by very slow reduction. In the temperature range from 400 to 600 °C, the rate of reduction increased with increasing temperature and increasing hydrogen pressure. Microscopic analysis showed that in this temperature range the reaction followed the shrinking core model. Above 600 °C, the reduction rate decreased noticeably before suddenly becoming very fast at and above 950 °C. Microscopy showed inner bands of metallization inside the outer metallic rim, indicating partial blockage of the interface between the reacted and un-reacted NiO core. At these temperatures, particle agglomeration and sintering were also found to take place. Surface segregation of sulphur may account for the slow down in reduction rate above 600 °C. From an industrial point of view, reduction should be carried out from 550 to 600 °C with as high a concentration of hydrogen as possible. If sintering and agglomeration are not of any concerns, reduction can be carried extremely fast at about 1000 °C.

Jan 1, 2005

By Wouter Bleeker, Isabelle Cadieux

"Abstracts of theses related to mineral deposit studies and exploration, completed at geology or earth science departments of Canadian universities, have been compiled for the period 1991 to mid-I993. Part I, presented in the June, 1994 issue of the CIM Bulletin, gave a listing of thesis titles. Part II. which consists of edited abstracts of theses considered to be of direct application to mineral deposit studies and exploration. is presented under various themes as follows:A. Kimberlites, Other Alkaline Intrusions and Related Studies;B. Volcanogenic Massive Sulphide Deposits and Related Studies;C. Mineral Economics;D. Mesothermal Gold Deposits. Other Gold Deposits and Related Studies:E. Magmatic Nickel-Copper, Platinum Group Element and Chromite Deposits and Miscellaneous Platinum Group-related Studies;F. Granite and Pegmatite-related Deposits and Porphyry Deposits;G. Diverse Hydrothermal Deposit,>, Sediment-hosted CopperDeposits and Mississippi Valley Type Lead-Zinc Deposits; andH. Uranium-related studies, Evaporites and Exploration Geophysics.Abstracts related to themes A to F were presented in previous issues of the CIM Bulletin, abstracts related to themes G and H are presented in this issue.G. Diverse Hydrotbennal Deposits, Sedimenthosted Copper Deposits and Mississippi Valley Type Lead-Zinc Deposits"

Jan 1, 1995

By Maureen A. McGuinness

Kidd Mine, an Xstrata Copper operation in Timmins, Ontario, operates a 400 t/h pastefill plant that provides paste backfill to stopes at the depth of 9000 ft. This paper will cover the operating practices of the pastefill plant both on surface and underground, highlighting tailings excavation, paste mix design and the pipe maintenance program. Kidd Mine, une opération d'Xstrata Copper à Timmins, Ontario, opère une usine de remblai d'une capacité de 400 t/h. Le réseau de distribution permet d'acheminer le remblai en pâte juste qu'à une profondeur de 9000 pi. Cet article couvrira le mode opératoire de l'usine de remblai tant à la surface que sous-terre en mettant l'emphase sur l'extraction des rejets miniers, la recette du remblai en pâte ainsi que le programme d'entretient du réseau de distribution.

Feb 1, 2008

By W. R. Hopkins, J. A. Davis

"This paper presents a discussion of the mechanisms by which aerosols of the process electrolyte are entrained into the breathing environment of copper, Zinc and nickel eIectrowinning tankhouses. Literature outlining the health effects associated with worker & posure to the acidic and metallic contaminants found in the airbome aerosols is summarized and compared with existing North American regulations.A brief review of the existing technologies for the source reduction of these aerosols is presented. This paper outlines the industry experience with use of covers, balls, beads, shapes, fixtures and chemical surfaetants. Each of these devices is ranked according to its effusiveness in the process in which it is used, and rated according to its operator acceptance.The various forms of existing in-plant ventilation systems are reviewed with a discussion of their relative merits and effectiveness. Actual experience is related, detailing the methods of testing for ambient contaminant levels in a variety of tankhouse environments. Guidelines are provided for the site and process specific criteria which govern the selection and ultimate effectiveness of a particular form of ventilation system.Finally, actual project experience is cited in which hydraulic modelling is used a design tool in tankhouse ventilation design. These projects include the upgrading of existing traditional ventilation designs, and the ''grass roots"" design of a more efficient aerosol source control system to be used in high altitude, cold weather sites."

Jan 1, 1994

By Jorge Blanco, Joaquin Gotor, Enrique Delgado, Carlos Frias

Since 2009 Cobre las Cruces (CLC) has successfully operated a sustainable mining business near Seville, Spain, applying the most advanced hydrometallurgical technologies to process secondary copper sulphide ores through atmospheric leaching in ferric sulphate media and using oxygen sparging in a cascade of ten reactors. In comparison to conventional copper smelters, the CLC hydrometallurgical process does not generate SO2 gas, airborne emissions or slags. The copper ore is ground and sent directly to atmospheric leaching reactors; flotation is not required, and consequently, copper extraction is maximized at 93-95%, while producing 72,000 t/y copper cathodes of the highest purity (99.999 wt.% Cu, Grade A). Reserves for the CLC deposit were estimated at 16 million tonnes of ore averaging over 6 wt.% Cu and containing principally a chalcocite mineralization. Other copper bearing species include digenite, covellite, chalcopyrite, bornite and enargite. Pyrite represents over 70 wt.% of the ore. In the CLC leaching process, chalcocite reacts with ferric sulphate at approximately 90 ºC and copper is released into solution while ferric ions are reduced to ferrous ions. The ferric sulphate leachant is regenerated continuously by oxygen injection and consumes sulphuric acid. It is remarked that pyrite plays a crucial role to yield high copper leaching rates. When pyrite is oxidized, a small proportion of iron is co-leached and some sulphuric acid is generated. The CLC leaching technology has been designed to allow a certain level of pyrite oxidation, which is positive in many ways: (i) to maintain a Fe/Cu ratio in solution; (ii) to facilitate Fe(II) oxidation; (iii) to produce a high redox potential; and (iv) to counterbalance a bleed solution that removes some iron. Moreover, galvanic interaction between pyrite (cathode) and chalcocite (anode) can substantially increase atmospheric leaching kinetics and efficiency (copper recovery).

Jan 1, 2016

By C. Matthews, A. Vo

Australia is one of the world’s leading exporters of bulk commodities and the extensive use of sampling equipment is key to the successful management of each mining operation. At the process plant, without a full understanding of the feed, product and tails, it is impossible to fully optimise the performance of the plant, such that the metallurgical balance is often open to error. At the port, a statistically correct, bias free and compliant sampling system is crucial to ensuring exported minerals are reflective of their true value and to avoid penalties. Over the last decade, as a result of the iron ore boom, there has been high demand for reliable, representative and standard compliant solids sample systems in Australia. This paper reviews several solids sampling applications at Australian mine sites, the challenges and experience gained and how the implementation of reliable representative sampling systems has provided better understanding of plant process performance, improved plant control and overall benefits to the operations. INTRODUCTION Mining is the primary contributor to the Australian economy with Australia ranking in the top 4 in economic resources for 21 primary industrial minerals in 2016 (Britt, et al., 2017). Australia is one of the world leaders in the export of the majority of its commodities including gold, copper and iron ore (Britt, et al., 2017). Therefore, a suitable and standard compliant sampling system is essential for evaluating plant performance and content verification. At the mine and at the port, the larger iron ore miners in Australia have developed stockpile models to predict the grade of their ore down to individual blocks of the stockpile. This allows the miner to create the right blend of material for sale to their customers and ensures they are not underselling their product or at risk of penalties for impurities or low grade. As an example, the average difference between the benchmark 62% Fe and low grade 58% Fe fines at the time of this report averaged US $20/tonne according to the Metal Bulletin Iron Ore Index (Fastmarkets MB, 2019). At a shipload of 180kt this would be a variation of US $3.6M. Whilst this is an extreme example, it highlights the economic importance of producing the correct grade product and a recognised representative sample of said product.

Jan 1, 2019

By Ji Wang

Reflective in-seam wave detection has the advantages of a far detection range and wide applicability. It has been successfully used in detection of many abnormal geological structures in work-faces, such as faults and collapse columns. However, a reflective in-seam wave is a dispersion wave. It has weak energy and is always covered by the direct in-seam wave. In the past, underground seismic explorations were not able to image the opposite roadway using reflective in-seam waves. To solve this problem, we propose a new method of reflective in-seam wave imaging based on adaptive dispersion filtering. This method processes the reflective in-seam wave using a filter with the parameter of transmission distance. The degree of similarity of the filtered and the explosion signal is used to estimate the transmission distance and image the reflective objects. We test and verify this method using real underground seismic data. This research is helpful for the detection of coal mine goafs and abandoned roadways in work-faces or in front of tunneling ends.

Aug 1, 2013

By D. Chadwick, J. W. Matousek

Between 1860 and 1890 -- from the time of the American Civil War to the last decade of the 19th Century -- nickel production in North America was dominated (even monopolized) by the output of the industrial complex of the Gap Nickel Mine near Lancaster, Pennsylvania and the American Nickel Works in Camden, New Jersey. In some years, from one sixth to one third of the world's metallic nickel supply came from this enterprise. Mining and smelting were conducted at Lancaster; a matte of high iron content was shipped to Camden for pyrometallurgical and hydrometallurgical refining to produce nickel metal, copper sulfate, and cobalt oxide. The high purity nickel product was rolled into sheet for marketing, primarily for coinage, as nickel had few other uses at that time. The undertaking experienced all of the problems that face the mining and metallurgical industries of today: declining reserves, high labor and fuel costs, high transportation costs, fluctuating demand and prices, pollution concerns, and foreign competition. The technical features of the geology; the mining, smelting, and refining operations; and some of the economic aspects are assessed. The view is taken from that of the present time -- seeking those lessons from history that we are supposed to learn or face the prospect of repeating the mistakes of the past.

Jan 1, 2005

By Christopher McElman

Real-time mine management solutions have evolved over time from closed, proprietary solutions, to a "system of systems" that may include a wide variety of off-the-shelf components and technologies. Modular Mining Systems has embraced open standards for their NextGen products to bridge the technology gaps between these systems. However, the remaining logical gaps must be overcome, in order to achieve truly seamless integration between discrete systems. When dealing with volatile real-time management problems, the effectiveness of business process modeling and middle-ware can break down. Scientific principles of military command and control applied to mining domain help to achieve better alignment and reach the highest level of integration. The combination of open standards and off-the-shelf hardware and software with a deliberately structured command-and-control approach provides a clear evolutionary path from ad-hoc connected systems towards real-time management of a seamlessly integrated digital mine.

Oct 1, 2009

By Carlos Antônio de Morais, Renata Dias Abreu

The present work describes a study of the separation of terbium and dysprosium from heavy RE concentrate through a solvent extraction circuit in a counter-current system. As the efficiency of the REE extraction by acid extractants rises with the increase of the atomic number of the element, the aim of this work is to extract the elements with higher atomic number maintaining Tb and Dy in the aqueous phase. Thus, terbium was separated first with subsequent separation of dysprosium. The experiments were carried out by using IONQUEST®801 as the extractant and a REE-hydrochloric liquor as feed solution. The optimum operational circuit in terbium separation was comprised of 37 stages: extraction, scrubbing, stripping, and solvent washing. For the dysprosium separation 39 stages were required. Terbium separation over 92% with over 95% purity and a Dy separation over 97% with over 95% purity were obtained.

Jan 1, 2014

By A. E. M. Warner, A. Vahed, P. J. Mackey

In the decade 2002 to 2012 some 6.7 million tonnes of new copper concentrate production capacity was brought on line, corresponding to 2 million tonnes of contained copper. This increase in concentrate supply necessitated the commissioning of a number of new copper smelters as well as the modernization and/or expansion of existing plants to meet the demand. This paper gives an overview of the copper extractive industry, reviews recent copper production trends and changes in the copper industry, including an examination of pyrometallurgical and hydrometallurgical technology developments. WorleyParsons has supported a number of the projects involved in these developments and this role is briefly discussed. The paper introduces a number of ideas related to possible future directions of the copper industry.

Jan 1, 2014

By Brian K. Ayres

Inco Limited, Ontario Division is currently in the process of decommissioning the Whistle Mine site located near Sudbury, Ontario, Canada. The most significant component of site decommissioning involved relocating approximately 6.4 million tonnes of acid-generating waste rock to the open pit from two adjacent stockpiles. An engineered cover system was designed for the backfilled pit to reduce the long-term production of acid rock drainage. Geochemical modelling was conducted to assess the effectiveness of various cover options on the longterm water quality of the backfilled pit. Results obtained from performance monitoring of cover system field trials at the site and estimated full-scale construction costs were used to select an appropriate material for the cover system barrier layer. The two-dimensional soil-atmosphere model VADOSE/W was used to develop a calibrated model of covered waste rock based on field data obtained from the cover trials, which was subsequently used to predict net percolation and oxygen ingress through various cover system alternatives for site-specific climate conditions. Erosion and landform evolution numerical modelling was completed to assist in designing the runoff management system and final landform for the pit cover system. The potential impact of various physical, chemical and biological processes on the sustainable performance of the pit cover system was also considered in the design process. This paper provides an overview of the design and construction of the backfilled pit cover system.

Apr 1, 2005

By K. P. Plucknett, Z. Memarrashidi

WC-Co ‘hard metals’ are widely used in a variety of industrial applications due to their resistance to abrasive wear, in addition to their high hardness and toughness. However, in contrast to their mechanical properties, the corrosion response of these materials is relatively poor. In the current work the corrosion mechanisms of two WC-Co cermets are analysed, with 10 and 30 vol. % of the Co metal binder, in a 3.5 wt.% NaCl aqueous solution. The assessment of corrosion involved a variety of electrochemical measurements, including open circuit potential, potentiodynamic polarisation and cyclic polarisation, together with systematic analysis of the post-corrosion solution chemistries using inductively coupled plasma optical emission spectroscopy. The corrosion potential and current density were determined, following Tafel extrapolation, allowing the calculation of the corrosion rates. It is demonstrated that continuous dissolution of the cobalt phase occurs during corrosion, which is a result of poor cermet passivation behaviour, and this response increases with the amount of binder in the cermet.

Jan 1, 2015

By Randolph A. Pax

"The internal operation of a tumbling mill is a very hostile environment and precludes the sustainable operation of internal sensors to measure the mechanisms of charge motion and breakage events. Instead indirect methodologies are required to expand the current understanding developed within a framework of perfect mixing of the mill contents. A number of measurement approaches have been successfully used to explore the operation of SAG mills including strain instrumented lifter bolts, mill shell strain measurement and thermal (energy balance) of operating mills.Early acoustics measurement was developed by Hardinge using a 'microphone' located close to the expected toe location. This signal was an indicator of the mill fill. Improvements were implemented with the use of two microphones straddling the toe location to try to increase the sensitivity of the measurement and reduce ambiguities. Further improvements included a filtered signal indicative of steel interactions. Unfortunately, the mechanisms of signal generation and the complexity of the processes do not provide a consistent signal.In recent years, advanced acoustic measurement using arrays of microphones utilising signal processing techniques have been implemented as SmartNoise and validated on over 30 mills. This paper will discuss the results obtained with signals such as water holdup, mill shell steel hits and two each of the toe and shoulder angles. An estimate of the internal mill component wear rates is also accessible.Advanced acoustic measurements with wide bandwidths when combined with physics models and process understanding has achieved a step change in the understanding of the dynamic internal operation of a tumbling mills on time scales of 80 ms. These techniques have been used extensively on SAG mills, but have also been applied to FAG and ball mills. Acoustic measurement is used for the rapid diagnosis of mill conditions and holistic control for optimisation and stability."

Jan 1, 2016

By M. E. Stutt, R. H. Rehder

"The mining industry is taking advantage of the increased performance resulting from the use of variable speed A C drives for large motors. This technology provides increased efficiency under the variable speed and torque requirements of such drives as mine hoists, conveyors, and air moving equipment. The technology does introduce voltage spikes on the voltage wave form that stress the insulation system to a greater degree than would occur with a constant voltage source. These voltage spikes must be considered in the design of the insulation system used for these motors.BackgroundHistorically the insulation systems for large AC motors were designed to withstand with reasonable life the voltage stresses of a 60 Hz constant sinusoidal voltage. One of the design tests is a voltage endurance test that requires the application of a 60 Hz voltage from conductor to ground equal to four to five times normal and establishing a time to failure. These higher than normal voltages accelerate the normal aging process by causing extensive partial discharge activity (corona) within the insulation system and the time to failure is a relative indication of insulation life.In addition to the voltage endurance test at 60 Hz, the individual coils are subjected to a surge voltage test to establish the withstand capability of the turn to turn insulation under switching surge conditions. The surge voltage is a fast rise time, 0.2 microsecond to crest value, voltage spike that can be caused by a circuit breaker or contactor closing operation. These voltage spikes can have a crest value of greater than 3.5 times the normal line to ground crest voltage of the normal 60 Hz power supply. The standard withstand test value is thus 3.5 times normal line to ground voltage. Because the voltage surges or spikes occur mainly during start and stop switching conditions, voltage endurance under these conditions has not been a major factor in insulation system design."

Jan 1, 1995

By E. Wusaty

"Fording Coal is a wholly owned subsidiary of Canadian Pacific Limited. The company was founded in 1968 to mine metallurgical coalfor export at the Fording River operations in southeast British Columbia.Today, Fording Coal Limited also operates the Whitewood mine under contract to TransAlta Utilities and the Genesee mine under a joint venture arrangement with Edmonton Power. Both these operations are located just west of Edmonton and produce subbituminous low-sulphur coal which is used for power generation. Fording also owns and operates two industrial mineral mines in the United States and is mining overburden under a lo-year contract with Syncrude Canada at Fort McMurray.As of December 1992, Fording Coal Limited owns and operates the Greenhills mine which was closed due to bankruptcy. This papers deals with the innovations and changes which have been made and those which are currently being implemented to make this operation competitive in the world export coal market. IntroductionOn December 4, 1992, following a tendering process, Fording Coal was awarded 80% controlling interest in the Greenhills mine by Trustee Arthur Andersen Inc. Assets acquired included 100010 of the land and coal leases and 80% of the major joint venture assets including all structures. The remaining 20% is owned by Pohang Steel Canada Ltd., a wholly owned subsidiary of Pohang Iron Steel Co. of Korea. The Greenhills mine had been in continuous operation since 1983 and was finally closed due to bankruptcy of its majority owner on October 31, 1992.A permit to operate the Greenhills mine was issued by the British Columbia government on January 29, 1993, and Fording Coal Limited started mining operations in late February 1993.To return the Greenhills mine to profitability significant changes were required in workforce productivity, mining methods and equipment selection. These mine plan changes are designed to make the Greenhills operation competitive in world markets, provide longterm employment for the company's workforce and ensure that a secure supply of coal is available."

Jan 1, 1994