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By J. Shahabpour

"Abstract - Breccias with angular and rounded clasts of a late-mineralization, ""barren"" hornblende porphyry dike set within a comminuted matrix consisting of rock fragments and quartz, cemented by quartz and K-feldspar of hydrothermal origin is observed in diamond drill cores from the Sar Cheshmeh porphyry copper deposit. Studies of age relationship between vein types, phyllic-altered clasts and the breccia groundmass suggest that the brecciation is a late event. The breccia clasts record evidence of hydrothermal reaction between the clasts and fluids responsible for the brecciation.Formation of bornite, in the breccia clasts of the originally barren hornblende porphyry dike, and in the breccia matrix, along with the scarcity of bornite in the Sar Cheshmeh deposit itself suggest involvement of fluids which are later and of different composition from the fluids responsible for the known mineralization at Sar Cheshmeh. These later fluids may be related to a later plutonic event and suggest the possibility of a later, and concealed deposit."

Jan 1, 1994

By F. Chiesa, Jeremy Carignan, B. Duchesne, D. Levasseur

"Aluminium A206 (AlCu4) is one of the strongest aluminium casting alloys with tensile properties approaching those of ferritic ductile iron. If the specification on the silicon content (< 0.05%) is easy to achieve during alloy ingot production, it is not the case in a foundry, where returns are used which are not perfectly cleaned from the silicate containing molding sand (Olivine). In alloy A206, the Si content is controlled in order to avoid the formation of a low melting point intermetallic phase (such as phase Q Al5Cu2Si6Mg2); these phases will melt during the solutionizing heat treatment to which alloy A206 must be subjected to develop its outstanding mechanical properties. This incipient melting may deteriorate the mechanical properties of Alloy A206 if the solutionizing treatment is applied at the standard temperature of 530°C.In the present study, a lower temperature solutionizing (520°C) was applied to a high Si content 206 alloy in order to reduce or eliminate the possible incipient melting. This was carried out on a complex shape industrial casting weighing 14 kg (31 lb) and 560x410x250 mm (22x16x10”) in size poured in aluminum 206 with a high silicon content (0.22% vs 0.05% max for alloy A206). Twenty ASTM E8 subsize tensile specimens were excised from two locations in the casting in order to compare the tensile properties for the two solutionizing temperature used (530 and 520°C). Optical and SEM microscopy allowed to investigate the causes of the differences in the properties observed between the 2 zones of the casting studied for 3 different heat treatments. INTRODUCTIONIn spite of their “textbook” outstanding mechanical properties (Up to twice the strength and elongation of the widely used A356 alloy), aluminum-copper alloys of the 2xx series are seldom used because of their propensity for hot tearing [Li, 2011], the segregation of copper [Cho, 2003], and their sensitivity to stress corrosion cracking [Jean, 2009, p. 113)]. Also, because of their wide freezing range and high thermal conductivity, a wide mushy zone makes feeding difficult, unless strong temperature gradients are created by liberal use of chills and risers in the critical zones of the part. Because they are prone to hot tearing, grain refining of Al-Cu alloys is particularly important, titanium playing a major role in the process [Sigworth, 2003]; grain refining has also been shown to be beneficial to fatigue strength [Jean, 2009, p. 103]. The practical basis of foundry practices pertaining to these alloys is outlined in an AFS webinar [Weiss, 2014]."

Jan 1, 2016

By Greg M. Hollyer

The search for minerals in the future will be dominated by deeper exploration and the need to accurately target ?blind? deposits as more and more of the ?easy? near surface targets are exhausted. In this context, key technologies are emerging for deep exploration both in grassroots and minesite exploration, including the Titan 24 Deep Penetrating geophysical technology. Introduced in 2001, this technology has grown rapidly into an accepted approach for exploration in a variety of geologic environments, including brownfield environments where discovering additional reserves would most quickly benefit companies. Titan 24 belongs to a new class of sophisticated Distributed Acquisition Systems (DAS) which record high-volume, high-quality data simultaneously at multiple receiver stations. This data is then processed digitally, modeled using specialized inverse modeling software, and interpreted according to geologic and other parameters. The result is a robust, high-quality, high-volume data sets which provide a basis for improved imaging to depth. In this paper, the Titan 24 distributed technology is discussed. Illustrations of the vast improvement to overall exploration are showcased through results in several case studies. These include examples from two gold deposits, a porphyry deposit and a minesite. These examples show the range of applicability of the technology and the ability to effectively image mineralization, lithology, structure and alteration to depth as an aid to understanding prospective mineral deposits and targeting drills more accurately.

May 1, 2008

By N. Ahern, M. Barbanell

Mercury is often present in gold ores and can be released during processing. In view of health and environmental concerns related to mercury, the mining industry takes leadership in the responsible management of mercury. This paper reviews various aspects of mercury management, including an overview of mercury deportment in typical gold processing flowsheets; trends in mercury legislation impacting the international flow and management of mercury in the gold mining industry; and treatment, storage and disposal options for mercury and mercury containing materials.

Jan 1, 2014

Purpose of TSUG Continuous Improvement in Mining Share Best Practises Exchange Ideas Network for Frontline Supervisors and Middle Management Meetings ? Two per Year -Spring and Fall ? Thirty Five to Forty Attendees ? Rotate Between Host Properties ? Host Mine Provides ? Meeting Room for One Day Tour of Mine and Maintenance facilities on Second Day

May 1, 2010

By John Campbell, William Trahant

"Total Quality Management (TQM) is becoming a reality in the mining industry. Widely adopted in the manufacturing and services industries, TQM has become the operating style of choice in numerous mining companies across the Americas and Australia. Iron Ore Company of Canada, Inco, MSA, Graniterock, Magma Copper, and CRA&apos;s Hamersly Iron - all are pioneers of TQM. These companies and others are confronting the challenges of implementing TQM and are managing the changes required of their people and cultures. What these companies are doing, why they are doing it, and how they are successfully managing the changes are the subjects of this paper.Driving the need for change in these organizations are a host of issues, some of which all mining companies are facing. Requirements from customers for ISO 9000 certification is becoming one of the initial motivators for Total Quality Management. These standards, commonly used in manufacturing throughout the European Community (EC), emphasize quality in the processes that create outputs, instead of just the outputs themselves. Iron Ore Company of Canada, for instance, responding to the requirement of one of its customers, British Steel, has become one of the first mining companies to meet the quality standard. Suppliers who meet the standards are highly desirable to customers who are themselves operating under the ISO or their national quality guidelines."

Jan 1, 1995

By Bruce Peberdy

Outline ?Building Systems ?Climatic Effects ?Thermal Effects ?Building Components ?Building Materials ?Structural Deterioration ?Maintenance Considerations

Nov 1, 2011

By J. G. Schofield, C. G. Tan, R. J. Ord

"Most electric furnaces in the nickel and copper smelting industries are still fitted with conventional electrode holders which consist of water-cooled electrical contact clamps and a pressure ring. The water cooling exerts a significant cooling effect on the electrode column. The importance of controlling the temperature of the Soderberg electrode paste at the contact clamp area is examined, using in-plant experience and computer simulation of the paste melting and baking process. In addition to the effect of water-cooling, the effect of other variables, including the mantle air temperature, the electrode current, the furnace freeboard temperature and the electrode slipping rate are discussed. Ways in which the variable heating conditions in the paste melting zone can be controlled are outlined.IntroductionIn most non-ferrous electric smelting operations, the breakage of Soderberg electrodes is an infrequent, isolated occurrence. Occasionally, however, a rash of breakages may be experienced on a particular furnace for what appears to be no obvious reasons. The extent of the breaks may not exhibit a uniform pattern; sometimes the break may be less than half a metre above the electrode tip; at other times it may be at or just below the roof level. The latter type of break is, of course, the most dangerous since it is closest to the non-baked, weak portion of the electrode paste column. No matter where the breaks occur, they result in abnormal furnace power, charging and tapping conditions and loss of production while the new electrode section is slipped and baked. On a six-electrode furnace, breakage on one electrode has the immediate effect of reducing the total furnace power by one-third. On a three-electrode furnace, the effect is more drastic, one half of the power being lost."

Jan 1, 1995

By V. S. Gischig, G. Preisig

Hydraulic stimulation of deep reservoirs is an essential procedure for developing engineered/enhanced geothermal systems (EGS), but also in other Geo-energy contexts. The goal is enhancing permeability to such a degree that fluid flow rates within the reservoir are sufficiently high for an economically productive reservoir. Two fracture stimulation mechanisms are distinguished that may occur concurrently during the hydraulic treatment: 1) During hydro-fracturing (HF) new tensile fractures are propagated from the borehole by means of a fluid pressure overcoming the minimal principle stress d3 plus the tensile strength T0 of intact rock. In case of a pre-existing fracture oriented normal to d 3 , the fracture can be opened by exceeding d 3 only. Fluid injection is performed via small packed intervals for creating a stack of hydraulic fractures. 2) During hydro-shearing (HS), over-pressure induces slip along pre-existing fractures that are favourably oriented in the stress field for reactivation in shear. Such stimulation is usually performed in a large packed interval or in an open borehole. Which mechanism occurs predominantly during stimulation depends on the rock mass structure and in-situ stress field, but also on the orientation of discontinuities intersecting the open-hole section and thus being pressurized. Both mechanisms also differ in how they affect fracture permeability. While permeability gained by HS is mostly irreversible due to rearrangement of asperity contacts accompanied with shear dilation, permeability enhanced during HF reduces nearly reversible after pressurization unless proppant is used to ensure permanent apertures. In this contribution, we critically discuss the pros and cons of both mechanisms regarding efficiency of enhancing permeability and the associated hazard of induced earthquakes based on literature review and numerical modelling. We review literature that reports on how much permeability required for productive EGS reservoirs and how much permanent permeability can be gained by stimulation. We also compile information regarding the degree of seismicity induced during HFor HS-dominated stimulation procedures, together with conceptual studies that reveal characteristics of seismicity associated with the two mechanisms. Many observations and models indicate that HF may have a higher tendency of being aseismic, while felt seismic events are usually associated with HS. Further, we present a hydro-mechanically coupled fracture flow model that investigates, if and to what degree the stimulation strategy can be designed such that one of the two mechanisms is evoked and dominates over the other. It shows that HS may dominate in presence of larger persistent fractures nearly optimallyoriented in the stress field, even if HF is attempted in short packed intervals. The model further demonstrates that stress transfer during HS promotes the development of permeability across an anisotropic layer of the stimulated rock instead of a large volume. Hence, the study sheds light onto the feasibility of creating productive EGS reservoirs in crystalline rock at several kilometres depths.

Jan 1, 2015

By K. G. Wheeland, K. G. Byberg

The occurrence of a secondary, dust-fuelled explosion following blasting of sulphide ores has been reported in mines in many countries, including canada, the USA, Australia and South Africa. However there has been little effort to document the events and develop effective control technology. Following a detailed investigation of an incident at the Geco Di vision of Noranda Minerals Inc. , the company held a conference of interested parties in October 1986 to review the state-of-the-art and to agree on action. '!his paper outlines the causes and effects of such explosions, the key conference points and conclusions, and subsequent information-exchange and teclmology-developrnent activities.

May 11, 1988

By Yan Jie

A series of production technologies are described for gold recovery from complex gold concentrate blended with copper concentrate treated in the SKS smelting process comprising: 1) Feed preparation and proportionate feeding of complex gold concentrate and copper concentrate; 2) SKS smelting gold recovery operation and process control technology developed based on reaction mechanism, process simulation and slag formation optimization study; 3) a dry-process quenching arsenic collection technology developed during de-bottlenecking severe restriction of SO3 in the off-gas on As collection system by suppressing and eliminating SO3 in off-gas as a result of optimizing SKS smelting process conditions and spraying caustic soda absorbent so as to reduce off-gas dew point temperature; 4) electrorefining of impure anodes; 5) technology for recovering such precious metals as Au, Ag, Pt, Pd, etc. from high-Sb copper anode slime produced as a result of gold recovery from complex gold concentrate by using SKS smelting process. INTRODUCTION Gold concentrate resources in China are mainly found in Shandong province, Henan province and the Inner Mongolia Autonomous Region, etc. Currently, recovery of gold is based on pre-oxidation (roasting) cyanide leaching process. This process produces a large amount of cyanide-containing wastewater, cyanide leaching residue and relatively high SO2-bearing flue gas during production, which can cause increasingly more serious environmental pollution issues. Besides, this process route suffers from a relatively low precious metals recovery (70–80%) found when treating refractory gold concentrate and carbon-bearing gold concentrate. These issues have severely restricted the development of the precious metals processing industry in China.

Jan 1, 2019

By Andrew Bamber

The mining and beneficiation of minerals is the second largest end-use of electrical power on the planet, and comminution is by far the largest single contributor to this. Several jurisdictions, including British Columbia, have, in response to concerns about greenhouse gas emissions and climate change, adopted energy conservation legislation, including carbon taxes, carbon trading and conservation incentive schemes. Key to achieving conservation objectives is firstly an understanding of usage metrics across the various unit operations in the sector, and secondly an understanding of the conservation potential represented by available technologies and approaches in reducing end-use. This paper presents the results of a recent utility-funded study on energy use metrics and conservation potential at large open pit mines which are typical of the sector in BC.

Aug 1, 2013

By Shahram Tafazoli

ABSTRACT: This article presents a novel technology for sensing the size of rocks after blasting in hard rock mines. Blast engineers require rock size statistics to carefully adjust the blasting parameters. The rock fragmentation requirements vary depending on the ore type and crusher specifications. The most popular statistical parameters in the industry are the so-called P numbers (e.g., P80 and P100). A machine vision based system is introduced here for automatic image collection and fragmentation analysis of the material right inside the bucket or dipper of mining shovels. A heavy-duty camera provides the required imaging data to an embedded computer mounted inside the cab. A custom machine vision software continuously analyzes the captured bucket images and stores the suitable ones in local storage which are then fed to a Desktop software for automatic fragmentation analysis. This technology has been developed by Motion Metrics International and is commercially available as FragMetrics?.

Oct 1, 2009

By Shahram Tafazoli

This article presents a novel technology for sensing the size of rocks after blasting in hard rock mines. Blast engineers require rock size statistics to carefully adjust the blasting parameters. The rock fragmentation requirements vary depending on the ore type and crusher specifications. The most popular statistical parameters in the industry are the so-called P numbers (e.g., P80 and P100). A machine vision based system is introduced here for automatic image collection and fragmentation analysis of the material right inside the bucket or dipper of mining shovels. A heavy-duty camera provides the required imaging data to an embedded computer mounted inside the cab. A custom machine vision software continuously analyzes the captured bucket images and stores the suitable ones in local storage which are then fed to a Desktop software for automatic fragmentation analysis. This technology has been developed by Motion Metrics International and is commercially available as FragMetrics?.

Oct 1, 2009

By Shahram Tafazoli

This article presents a novel technology for sensing the size of rocks after blasting in hard rock mines. Blast engineers require rock size statistics to carefully adjust the blasting parameters. The rock fragmentation requirements vary depending on the ore type and crusher specifications. The most popular statistical parameters in the industry are the so-called P numbers (e.g., P80 and P100). A machine vision based system is introduced here for automatic image collection and fragmentation analysis of the material right inside the bucket or dipper of mining shovels. A heavy-duty camera provides the required imaging data to an embedded computer mounted inside the cab. A custom machine vision software continuously analyzes the captured bucket images and stores the suitable ones in local storage which are then fed to a Desktop software for automatic fragmentation analysis. This technology has been developed by Motion Metrics International and is commercially available as FragMetrics?.

Oct 1, 2009

By Eiichi Sato, Koichi Kitazono, Hiroshi Masuda, Kenta Higane

"The present study investigated the low-temperature creep mechanisms in ultrafine-grained (UFG) aluminum manufactured by accumulative roll bonding. UFG aluminum with grain size 0.39 µm showed steady state creep even at room temperature under low stresses as confirmed by the creep curves in the strain rate–strain plot. The low-temperature behavior was divided into four regions by three distinctive stresses, sI, sII and sIII: sI (=45 MPa) is denoted as the micro-yielding stress with which dislocations start movement, sII (=85 MPa) the dislocation-multiplication stress above which dislocations multiply with creep deformation, and sIII (=171 MPa) the conventional yield stress above which macroscopic plastic strain is generated. During low-temperature creep, below sI, negligible plastic strain is generated. Between sI and sII, creep deformation with stress exponent 2.5 occurred, which is accommodated by dislocation absorption into grain boundary and grain boundary sliding, similarly to the low-temperature creep of HCP metals. Between sII and sIII, creep deformation with stress exponent 7.0 occurred, whose mechanism is similar to the low-temperature creep of coarse-grained aluminum. Above sIII, power-law breakdown occurred.INTRODUCTIONIt is well understood that the creep deformation brings about at high homologous temperatures (T/Tm) of >0.4, where Tmis the melting point, with diffusion processes. Recently, the importance of aluminum is increasing for cryogenic temperature parts such as a metallic liner or a cap in high pressure-hydrogen vessels, and the presence of creep behavior in aluminum at room temperature has become recognized (Matsunaga, 2013;Kassner, 2015).In HCP metals and alloys, especially intitanium, steady-state creep behavior appears at room temperature with apparent activation energy of1/10 of that for self-diffusion(Neeraj, 2000; Matsunaga, 2009).On the other hand, Kassner (2015) claims that aluminum shows creep behavior at room temperature with apparent activation energy of 4/5of that forself-diffusion, but never reaches the steady state. We should note that it is derived from the data obtained from short-term creep tests of few hour, and Matsunaga (2013) already claimed the presence of steady state in room temperature creep in aluminum with activation energy of 1/5of that for self-diffusion.The mechanisms for low temperature creep are considered different between HCP and FCC metals: in HCP metals, grain boundary sliding is observed and is thought to accommodate piled-up dislocations at grain boundaries through absorbing them. The so-called slip-induced grain boundary sliding occurs with low number of activated slip systems(Matsunaga,2009).On the other hand, in FCC metals, many activated slip systems bring about work hardening with dislocation cell structure formation. In the initial stage of creep, it results in primary creep (Kassner, 2015), but Matsunaga (2013) claimed that once the annihilating of a cross-slipped dislocation to another reaches balance, steady state is established. It has been, however, strongly required to show more convincing experimental verification for the presence of steady state in FCC metals at low temperature."

Jan 1, 2018

By Bétournay. M. C.

Advantages ?Safety ?Health ?Rapid, continuous development, productivity ?Stope dilution reduction Disadvantages ?High cost and long time for equipment development ?Hard rock mining condition limitations ?Size of equipment ?Equipment set-up time, down time ?Performance does not meet financial return targets ?Drill and blast retains advantage in cost, productivity, capital investment, application flexibility ?Stress accumulation issues in deep mining, ground support and material handling issues in weaker rock

May 1, 2009

By Michael Moser, Brighty Dutta, David Dreisinger

"Molybdenum is widely used in the industries as an alloying element in the manufacture of steels and super alloys. The widespread use of the element encourages a growing need to develop extraction processes for recovery from both primary and secondary sources. The Solvay Group has developed a solvent extraction reagent named CYANEX®600 for the recovery of molybdenum from acidic solutions originating from both low grade (e.g. copper solvent extraction raffinates, smelter dusts and slags) and high grade (molybdenite) molybdenum sources. CYANEX®600 is a purified form of CYANEX®272 with the active component bis(2,4,4- trimethylpentyl)phosphinic acid. The extraction behavior of CYANEX®600 towards molybdenum in sulphuric acid medium was evaluated. The uptake of molybdenum increased with the increase in concentration of CYANEX®600. The approximate stoichiometry of the extracted complex was: Mo: CYANEX®600 = 1:2. Efficient back-extraction could be achieved with 0.1 M disodium EDTA and 0.1 M (NH4)2CO3, thus providing the option of recyclability of the extractant. The detailed back-extraction studies are currently under progress to find out the possible option for complete transfer of Mo(VI) to the aqueous phase so that high purity Mo salts could be precipitated from the molybdate solutions.INTRODUCTION Molybdenum (Mo) is one of the world’s valuable metals and is highly sought after by researchers due to its versatile mechanical, thermal, chemical properties. Swedish scientist Carl Wilhelm Scheele demonstrated molybdenite to be a mineral sulfide in 1778. Peter Hjelm successfully isolated dark metal powder from the mineral sulphide and named it as ‘Molybdenum’ in 1782 (Gupta, 1992). Molybdenum is a refractory metal of silver gray appearance and is an important alloying element used in the manufacture of steels and super alloys. Molybdenum compounds are widely used in formulation of catalysts (Gupta, 1992). Molybdenum occurs in nature only in chemical combination with other elements. Several molybdenum bearing minerals have been identified, but the only one of commercial significance is molybdenite (MoS2). As molybdenum is a strategic metal for the industrial sector, its widespread use acts as a factor for depletion of the natural resources. Hence, there is growing need to develop extraction procedures for its recovery from both primary and secondary sources. United States, China, Chile, Canada, Peru, and Mexico are listed as the main producers by the U.S. Geological Survey, 2016 (U.S. Geological Survey, Mineral Commodity Summaries, January 2016)."

Jan 1, 2017

By William A. Napier

The Mantaro Phosphate Property is located ~ 250 km east of Lima, Peru in the Andean altiplano near the city of Huancayo, Junin District. The Mantaro deposit is a mineralized zone of phosphatic rock currently defined by surface outcrops, trenches and drilling extending over a strike length of more than 30 km and a width of more than 5 km covering ~27,700 hectares. Mineralization is exposed as three roughly parallel exposures (?mantos?) trending in a northwest-southeast direction along the Mancaspico syncline. Estimated mineral resources1 contained in Manto 1 of the Property (4% P2O5 cut-off) as of February 21, 2010, are: Measured 5.548 million tonnes @ 10.8% P2O5 Indicated 33.975 million tonnes @ 9.9% P2O5 Measured + Indicated 39.523 million tonnes @ 10.0 % P2O5 Inferred² 376.265 million tonnes @ 9.0% P2O5 1Tonnes rounded to the nearest 1,000 and grade to 1 decimal place. 2Inferred material reported with no cut-off and an assumed grade. There is considerable potential to expand the resource base. Mantos 2 and 3 of the deposit have been geologically mapped and exhibit surface mineralization widths similar to Manto 1. Given that the deposit is of marine sedimentary origin, it is reasonable to infer that comparable grades and depth of mineralization are present within Mantos 2 and 3. Based on this assumption, the potential mineral deposits within Mantos 2 and 3 are estimated to be approximately: Manto 2 425-435 million tonnes @ 9% P2O5 Manto 3 280-290 million tonnes @ 9 % P2O5 These potential quantities and grade are conceptual in nature, there has been insufficient exploration to define a mineral resource and it is uncertain if further exploration will result in these targets being delineated as a mineral resource. However, should such conceptual resources be confirmed by trenching and drilling, the Mantaro Phosphate Property would rank as one of the most significant phosphate deposits in the world.

May 1, 2011

By C. H. Ash

"Abstract-The Red Chris Cu-Au deposit (522.7 Mt at 0.35% Cu and 0.27 g/t Au), northwestern British Columbia, is one of several pre-accretionary porphyry systems in the Cordillera of western Canada. It is hosted by an Early Jurassic hornblende monzonite to quartz monzodiorite porphyry which forms part of a suite of dikes and stocks that intrude Late Triassic volcanic strata. Major and trace element chemical data suggest that these Early Jurassic intrusions have compositions which fall on the boundary between alkalic and calc-alkalic compositions. Alteration and mineralization in the Red Chris deposit are more typical of calc-alkaline porphyry systems with abundant potassic, sericitic and argillic assemblages and quartz-rich stockworks. It lacks Na- and Ca-bearing silicate assemblages which characterize the alkalic porphyry deposits of British Columbia. One of the more unusual features of the deposit is the abundance of carbonate alteration and veins which occur throughout the hydrothermal history of the deposit. This type of alteration and veining is more typical of alkalic porphyry deposits. The composition of the carbonates vary both temporally and spatially with different alteration zones. Potassic zones, which are characterized by orthoclase±albite±quartz±chalcopyrite±bornite± magnetite±hematite and Au/Cu ratios of 1:1 (g/t Au:% Cu), contain minor siderite veins and alteration. Quartz-sericite-carbonate (QSC) zones overprint earlier potassic alteration and comprise quartz+ankerite+sericite+pyrite+chalcopyrite with Au/Cu ratios of 0.5:1 (g/t Au:% Cu). Ankerite is the main carbonate in this stage but has a variable composition with a more Fe-rich variety associated with mineralized veins. Localized chlorite-carbonate alteration zones, characterized by chlorite+ carbonate+quartz±kaolinite±pyrite±gypsum and high Au/Cu ratios [2 to 3.5:1; (g/t Au:% Cu)], contain predominantly calcite. Late stage carbonate-gypsum veins have an ankerite to dolomite composition which is very similar to the regional carbonate alteration and veins."

Jan 1, 1997