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By E. Suárez, V. Rivasplata

El proyecto Piel Canela está ubicado en los distritos de San Luis y San Bernandino en la provincia de San Pablo dentro de la región Cajamarca. La geología muestra unidades volcánicas del Paleógeno (Paleoceno – Eoceno/Oligoceno) las cuales se presentan deformadas. El basamento en el área de estudio está representado por secuencias de depósitos volcanoclásticos gris verdosos intercalados con flujos de lava, de manera concordante ocurre sobreyaciendo a esta unidad una secuencia de flujos piroclásticos de pómez y cenizas con intercalaciones de flujos de lava compactos. Además se observan en las partes más altas flujos piroclásticos de composición dacítica rica en cristales con coloraciones gris blanquecinas.

May 1, 2008

By S. Skowronski

PURPOSE OF INVESTIGATION Since cuprous chloride melts at 418° C., boils at 954° C. to 1033° C.,1 and is known to be volatile at a much lower temperature, the presence of chlorine in any form in or on copper to be melted has always been looked upon by copper refiners as a possible source of-serious copper loss. Although this fact has been known for some time, the copper literature contains little or no information regarding it and the field seems .never to have been properly investigated from a metallurgical standpoint. According to Greenawalt,2 cupric chloride, CuCl2, when ignited gives cuprous chloride; therefore cuprous chloride is always formed when copper enters into reaction with chlorine at a high temperature. Cuprous chloride melts somewhat below a dull red heat, and does not volatilize in closed vessels, even if strongly heated, but if heated in the air it goes off as a white vapor. Hofman3 gives the melting point of cuprous chloride

Jan 2, 1919

By R. K. Kandasami

"Naturally occurring geomaterials such as sandstone, limestone and other soft rocks, residual soils are composed of a particulates held together through a cohesive matrix, usually composed of argillaceous or siliceous cementing agents. Geo-materials such as these have been reconstituted in the laboratory using ordinary Portland cement in lieu of the naturally occurring cohesive matrix, in addition to using sand particulates. This cohesive frictional granular ensemble is an ideal model material for understanding the mechanical behaviour of transitional geomaterials such as soft rocks. An important consequence of this cohesion that pervades the inter particulate system is the enhanced tensile strength when compared to a purely granular ensemble. The assessment of strength of these soft rocks and cemented sands is often understood in the framework of continuum mechanics, i.e. considering the cemented sand to be a continuum, and performing simple elemental tests such as uniaxial compression or tension tests. A simple model to describe the behaviour of these cemented sands has been to use elements such as springs, sliders, and dashpots in parallel to describe the existence of a cohesive and frictional component of strength (Jiang et al. 2007). In the framework of continuum mechanics, the mechanical response of these cemented sands have been modeled using traditional plasticity theory, for example utilizing variants of the traditional Mohr Coulomb model, Modified cam clay (Sun and Matsuoka 1999) etc. The typical sand models are amended to include the effects of cohesion, as proposed by Lagoia and Nova (1995).The mechanical response of cemented sands is understood to be transitional to the behaviour of a typical particulate assemblage and a quasi-brittle material. However, the effect of length scale in these material systems has not been investigated. This paper presents a series of uniaxial compression experiments conducted on weakly cemented sand specimens of various sizes. The effect of length scale in these weakly cemented sands is investigated through unconfined compression tests."

Jan 1, 2015

By Zhijing Zhang

Long-term thermal stability of ionic liquids is essential for reliable performance of ionic liquids in any engineering applications. TGA studies were carried out on a series of ionic liquids with different cations and anions such as 1-butyl-3-methylimidazolium chloride ([C4mim]Cl), 1-hexyl-3-methylimidazolium chloride ([C6mim]Cl), 1-hexyl-3¬methylimidazolium tetrafluoborate ([C6mim]BF4), 1-hexyl-3-methylimidazolium hexafluorophosphate ([C6mim]PF6), 1-octyl-3-methylimidazolium hexafluorophosphate ([Csmim]PF6), and 1-butyl-3-methylimidazolium bis(trifluromethanesulflonyl)imide ([C4mim][Tf2N]). The short-term thermal stability of ionic liquids was evaluated by measuring the onset temperature of decomposition of ionic liquids, and the long-term thermal stability of ionic liquids was also evaluated by weight loss of ionic liquids over a long period of time at various temperatures. The experimental results showed that the long-term thermal stability of ionic liquids decreased with increasing temperature and was significantly lower than the onset temperature of decomposition of ionic liquids.

Jan 1, 2002

By Armand Bur, W. R. Reichenstein

Since coal is one of the largest cost items in the production of electricity, its analysis for heat value and composition has been the subject of intensive study. Sampling started with crude hand methods, out of the railroad car or barge or from moving conveyor discharge, and progressed to reliable mechanical in-plant sampling systems. The mechanical system takes its sample from a falling stream of coal such as a conveyor discharge or crusher discharge hopper. But this has a disadvantage in that the identity of the coal is lost. Coal is shipped to the user in train-loads, often made up of shipments from various mines. When the cars are dumped into hoppers and the coal conveyed to the power station, the various shipments become mixed because residual coal remains in hoppers and chutes.

Jan 5, 1959

By H. E. Nold

THE raw materials of the ceramic industry are mostly clays. This raw material is ground, water is added and the mixture pugged into a moist, plastic, rather stiff mass. From this mass the desired units of manufacture are made (bricks, hollow building tile, sewer .pipe, etc.). These units are dried; then placed in kilns and heated until the desired degree of vitrification is obtained.1 For firing ceramic ware, two distinct types of kilns are used; namely, periodic and continuous tunnel. PERIODIC KILNS Periodic kilns are those ordinarily seen in a brick plant. They are either round or rectangular. The raw, dried, formed ware is piled or set in the kilns to depths frequently exceeding 10 ft. The kiln is heated until the ware is matured, then gradually cooled sufficiently to allow men to remove the ware; then the cycle is repeated. The time duration of the cycle may be more than two weeks.

Jan 1, 1933

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

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

Jan 1, 2019

By H. H. Storch

"INTRODUCTION The first paper of this series contained data concerning the behavior of polyhalite (K2S04.MgS04.2CaS04.2H20) upon calcination and subsequent leaching with water at 100° C. It was found that upon heating polyhalite to temperatures between 298 and 500° C. the water of crystallization is driven off, leaving, an amorphous mixture of K2S04, MgS04, and CaS04. Two transition points were located; one at 298° C. which coincides with the vigorous evolution of steam; and one at 551° C. which results in the formation of a hard mass of crystals. The latter probably consist of a solid solution If the compounds langbeinite (K2504, 2MgS04), potassium dicalcium sulphate (K2304. 2CaS04), and anhydrite (CaS04). The heat of decomposition of polyhalite at 298° C. was measured and found to be 66,000 ± 5,000 calories per mol. The optimum temperature of calcination with regard to subsequent extrac¬tion with two parts of water (at "" 0° C.) is 430 to 450° C. for 65 to 100 mesh material, if one half hour at the calcination temperature is allowed. The maximum concentration of K2S04 obtainable in the extraction of calcined polyhalite is 11.4 grams per 100 grams of water. This concentration of K2304 is considerably above the equilibrium value (3.6 g. per 100 L. of H20 at 83° C.) with respect to the solid phases polyhalite, potassium calcium pentasulphate, ¬and anhydrite. The figure 11.4 K. of K2804 per 100 g. of H20 is also somewhat than the equilibrium value (9,65 g. per 100 g, H20) with respect to the solid phases potassium calcium pentasulphate and syngenite."

Oct 1, 1930

By C. C. Wright, T. S. Spicer, R. G. Bowman

In recent years considerable publicity has been given to the problem of atmospheric pollution by fuel-burning equipment. Legislation has been stimulated and smoke ordinances have been enacted, the provisions of which show a definite trend toward stricter control of the emissions not only from the stacks of industrial fuel users but also from the chimneys of domestic consumers. As a result of war conditions, some slackening in the enforcement of these ordinances may be noted, but this is only a temporary expediency caused by the changes necessary in the distribution of the nation's fuel supplies and difficulties in securing the necessary equipment. Previous trends may be expected to continue in the postwar period. Largely because of the consumer demand for automatic heat, but partly because of the legislation against smoke emission, there has been a marked increase in the use of domestic underfeed stokers with the past decade. When correctly adjusted and operated, these units reduce the smoke emission materially, so that even the high-volatile bituminous coals may be burned with little or no emission of objectionable smoke. Unfortunately, however, the use of the domestic underfeed stoker introduces another problem; namely, fly-ash. Production of Fly-ash The term "fly-ash" is a misnomer, since the fly material is generally a mixture of small carbonaceous particles varying from green coal to coke, and inorganic particles ranging from fluffy ash to small particles of fused clinker. For want of a more comprehensive name, however, the term fly-ash is used throughout this paper to include all the fly material. Even with hand-fired furnaces a certain amount of fly-ash is produced, which necessitates periodic cleaning of the boiler flues or furnace radiator, the smoke pipe, and occasionally the chimney itself. With stoker operations the amount of fly-ash is increased many fold, because of the higher velocity of air travel through the fuel bed. Frequently the amount of this fly-ash attains such proportions as to constitute a definite nuisance to the householder and his neighbors and distracts very materially from the otherwise automatic or semi-automatic performance of the stoker. Virtually all the boilers and hot-air

Jan 1, 1944

By T. S. Spicer, C. C. Wright, R. G. Bowman

In recent years considerable publicity has been given to the problem of atmospheric pollution by fuel-burning equipment. Legislation has been stimulated and smoke ordinances have been enacted, the provisions of which show a definite trend toward stricter control of the emissions not only from the stacks of industrial fuel users but also from the chimneys of domestic consumers. As a result of war conditions, some slackening in the enforcement of these ordinances may be noted, but this is only a temporary expediency caused by the changes necessary in the distribution of the nation's fuel supplies and difficulties in securing the necessary equipment. Previous trends may be expected to continue in the postwar period. Largely because of the consumer demand for automatic heat, but partly because of the legislation against smoke emission, there has been a marked increase in the use of domestic underfeed stokers with the past decade. When correctly adjusted and operated, these units reduce the smoke emission materially, so that even the high-volatile bituminous coals may be burned with little or no emission of objectionable smoke. Unfortunately, however, the use of the domestic underfeed stoker introduces another problem; namely, fly-ash. Production of Fly-ash The term "fly-ash" is a misnomer, since the fly material is generally a mixture of small carbonaceous particles varying from green coal to coke, and inorganic particles ranging from fluffy ash to small particles of fused clinker. For want of a more comprehensive name, however, the term fly-ash is used throughout this paper to include all the fly material. Even with hand-fired furnaces a certain amount of fly-ash is produced, which necessitates periodic cleaning of the boiler flues or furnace radiator, the smoke pipe, and occasionally the chimney itself. With stoker operations the amount of fly-ash is increased many fold, because of the higher velocity of air travel through the fuel bed. Frequently the amount of this fly-ash attains such proportions as to constitute a definite nuisance to the householder and his neighbors and distracts very materially from the otherwise automatic or semi-automatic performance of the stoker. Virtually all the boilers and hot-air

Jan 1, 1944

By Hu Wenjun, Li Maonan

Mine ventilation systems mostly are ventilation networks with fixed-quantity branches. The solution to the problem of ventilation networks with fixed-quantity branches is obtained by choosing the fixed quantity branches as chords and using Hardy Cross iteration method. The solution usually is feasible but may be not economical. This paper takes minimal annual ventilation electricity cost as an object, considering the power of main fans and boosters, natural ventilation pressures and resistances of regulators, and builds up a nonlinear programming model. A set of initial values of the nonlinear programming can be obtained by using Hardy Cross method, The MAP technique then used to find a set of local optimal solution The running procedure with a simple example is dicussed. Mine ventilation systems mostly are ventilation networks with fixed quantity branches. In the networks, air quantity of branches are generaly regulated by increasing branch resistance or air pressure. A comon approch to the of the networks with fixed quantity branches is to formulate it based on Kirchhoff's current and voltage laws and the solution is obtained by Hardy Cross iterative technique. The solution usualy is feasible but may be not economical. The optimal plan of air quntities regulation of mine ventilation network should be to make the solution satisfy both required quantity of work places and minimal ventilation operating cost. It is the purpose of this paper to introduce a new approch and computational experience of nonlinear programming of the optimal problem.

Jan 1, 1991

By J. E. Kogel

Industrial minerals play a central and dual role in the sustainable development (SD) of natural resources. Over the past decade the mining industry has increasingly focused on sustainably extracting and processing industrial minerals. This trend has been driven by higher energy costs, diminishing water resources and sensitivity towards environmental stewardship. Industrial minerals have been used throughout human history as low cost, naturally occurring, materials. Today they are critical components of recycled packaging, energy efficient building materials, light weight paper coatings, and other products critical to the responsible utilization of global resources. As industrial minerals become more widely used in ?green? products, mining companies have established best practices for the sustainable management of industrial minerals mining and processing. These management practices include reducing energy consumption, minimizing water usage, increasing waste recovery through recycling and process optimization, and maximizing the amount of ore extracted per acre of disturbed land. With the commitment to SD principles, quantitative methods for objectively measuring SD performance have become increasingly important. Measuring sustainability impact is a valuable tool for effectively applying SD principles and for making choices that balance sustainable development against other business objectives. SUSTAINABLE DEVELOPMENT AND MINING Sustainable development is a term that has become a common part of our lexicon; however, it has multiple meanings and interpretations leading to a sometimes confusing and contradictory array of definitions. The absence of a single, precise definition reflects the fact that SD is a broad concept or paradigm that offers guiding principles as opposed to a specific set of criteria or regulations enforceable by government or other oversight agencies. While a principle based conceptual approach allows businesses to broadly apply SD practices that are tailored to their specific situation, it has also led the public to sometimes view voluntary corporate SD programs with a degree of skepticism (Walker and Howard 2002). This is particularly true in the mining industry. One reason for this skepticism is that the relationship between SD and mining is misunderstood and to many, sustainably developing non-renewable mineral resources is a contradiction (Rajaram et al. 2005). However, this view takes a very narrow interpretation of the tenets of SD. The second is that mining carries a legacy of poor environmental stewardship that does not accurately reflect current corporate environmental practices Many minerals companies have adopted the Brundtland Comission?s definition of SD (United Nations 1987): ?? development that meets the needs of the present without compromising the ability of future generations to meet their own needs?. This definition is very broad and can be interpreted in a number of ways. It provides a general context for sustainable development and is not intended to provide detailed guidelines addressing specific aspects of sustainable development. To fill this gap the following SD principles were drafted by the international minerals community in 2003 (ICMM 2003): 1. Implement and maintain ethical business practices and sound systems of corporate governance. 2. Integrate sustainable development considerations within the corporate decision-making process. 3. Uphold fundamental human rights and respect cultures, customs and values in dealings with employees and others who are affected by our activities. 4. Implement risk management strategies based on valid data and sound science. 5. Seek continual improvement of our health and safety performance. 6. Seek continual improvement of our environmental performance. 7. Contribute to conservation of biodiversity and integrated approaches to land use planning. 8. Facilitate and encourage responsible product design, use, re-use, recycling and disposal of our products. 9. Contribute to the social, economic and institutional development of the communities in which we operate. 10. Implement effective and transparent engagement, communication and independently verified reporting arrangements with our stakeholders. These guidelines insure that SD concepts are applied equally across the industry while setting a clear performance standard and benchmark against which to evaluate success. By adopting these principles and issuing the Milos Statement (http://www.sdimi.org/milos_decl_October%206_2003.pdf), which provides a more detailed vision for integrating SD into everyday business operations, the minerals industry has embraced SD as a core corporate value. The unifying and holistic approach embodied in SD principles impacts the entire mine to market life cycle and addresses the economic, environmental and social consequences of mining. INDUSTRIAL MINERALS The world economy relies heavily on minerals; they are essential to economic prosperity and the quality of life. Industrial minerals are non-metallic, non-fuel minerals that provide the raw materials for a vast range of products used in most every aspect of daily life. They are mined and processed worldwide and they span the spectrum from relatively low value, high volume commodities (e.g. common clay, crushed stone) that are usually mined locally to high value, low volume specialty materials that are sourced from unique one of a kind deposits (e.g. barite, talc, mica). High volume commodity mining operations are often located near the end use market which, in most cases, means areas of high population density where construction and other urban activities drive demand. In these situations the strict adherence to SD principles is particularly critical as these are highly visible operations that must meet the public?s demand for good corporate citizenship. These operations are similar to chemical or other manufacturing facilities that operate near population centers. In contrast, some mining operations are located in remote but environmentally sensitive regions of the globe where the pressure to mine sustainably is driven by the need to preserve habitats and other

Jan 1, 2009

By E. A. Adey, C. Baciu, P. Whitbread-Abrutat, M. Varul, T. Ejdemo, R. K. Shail, F. Wall

Responsible mining requires stakeholder engagement throughout all operational stages and after mine closure. By assessing the current and anticipated future socio-economic and environmental impacts, a company can maximise the positive impacts they can have on a community, whilst minimising any negative impacts. Despite the current emphasis on companies maintaining effective stakeholder relations to gain their ‘social license’ to operate, findings of the present study reveal a wide variation in community expectations, with different degrees of ‘acceptability’ evident across seven sites in Romania (Rosia Montana), Sweden (Kristineberg), the United Kingdom (Cornwall), Bosnia Herzegovina (Vihovici) and Russia (Karabash, Gay and Mednogorsk). These variations reflect the current status of mining within a community, as well as its socio-economic background and the nature of existing engagement with mining companies already operating in the region.

Jan 1, 2011

By T. G. Carter

"Damaging seismicity associated with deep faulting in both mining and civil excavations not infrequently occurs without warning, and often before proper mitigation measures have been put into place. Severe squeezing is also a common problem for excavating through deep major faults. While both problematic conditions are difficult to predict and characterize, there is often a need at pre-feasibility and feasibility level to more reliably estimate the possible level of risk posed by such geologic structures. This paper introduces some structural geologic techniques that have potential application for both mining and civil applications for aiding forewarning of the extent of these types of problem.INTRODUCTIONEncountering adverse faulting at depth in deep excavations, whether for mining or civil purposes can create serious economic and safety impacts. For deep mines or for deep tunnel projects, measures are available for aiding prediction of the extent of possible influence that large scale faults could create, but these techniques are rarely if ever applied as part of routine site investigation programs, or even as part of risk assessment evaluations. Several well established structural geologic methods of palao-history reconstruction have potential application for aiding forewarning of the extent of these types of potential problem by allowing estimates to be made of:• controlling stress orientations that might engender reactivation movement;• principal stress magnitudes that could lead to failure initiation, and• probable mechanisms of fault deformation - brittle (bursting) or plastic (squeezing).This paper explores several structural geological and rockmass characterization techniques that have application for unravelling fault structure of importance to deep engineering projects. Their application for mining or tunnelling purposes is advocated in conjunction with conventional rockmass characterization assessment approaches using GSI, RMR and/or Q to aid early recognition and definition of potential adverse ground condition behaviour associated with intersection of significant faulting at depth."

Jan 1, 2015

By A. E. Bellis

THERE is a wide difference of opinion among rifle experts in the matter of barrel steel, and the relative importance to the life of the barrel of the steel's composition, heat-treatment, structure, and physical properties. In order to promote discussion, which it is hoped may lead to the discovery of the source of 'some of the traditional beliefs on the subject, the results of some tests are presented here, with data on heat-treating, physical tests, and erosion. The detailed metallographic study of this steel is given in another paper.1 The conclusions from these tests should be capable of wider application than their direct bearing on the barrel-steel problem. The Government specifications for barrel steel for model 1903 rifle (Springfield) call for carbon 0.50 to 0.60 per cent., manganese 1.00 to 1.29 per cent., silicon under 0.25 per cent., sulfur under 0.06 per cent., phosphorus under 0.08. per cent. The minimum physical requirements are: Tensile strength,- 110,000 lb. per sq. in. (7733 kg. per sq. cm.); yield point, 75,000 lb. per sq. in (5472 kg. per sq. cm.); elongation, 20 per cent.; reduction of area, 45 per cent. Material fulfilling these requirement's gives practically no failures when proof-fired, with charge of 70,000 lb. per sq. in. pressure, which is 40 per cent. in excess of the service charge. The turning and drilling operations show up any seams or laps such as accidentally occur even in- the best heats of open-hearth steel, so that' faulty stock is practically all eliminated before proof-firing. These physical requirements are met either by rolling billets at, a proper temperature clown to the form of tapered barrel blanks or by heat-treating bars that have been upset to enlarge the breech section. The transformation temperature of this steel, on heating, is around 1350° F. (732° C.), varying somewhat with the composition and the rate of heating. The actual treatment of the barrel blanks, as carried out by different

Jan 7, 1919

By Jerold Bishop, Grant Bearss, Aleksey Egorov

"When a shock wave is released in the bottom of a drill hole filled with wet concrete slurry, the result is called an electrohydrodynamic effect, or EHDE. The energy is carried through the fluid with minimal loss because the slurry is an incompressible medium. Repetitive discharges provide a series of energy pulses that compact the soil along the pile shaft and at its base. The process is analogous to repeated applications of low-energy blast densification or to dynamic compaction. In general, the process is not depth dependent. EHDE was identified in the 18th century by an American scientist who observed that a spark between two electrodes placed under water induced a burst of pressure. In 1957, two Russian engineers formulated a process and received a patent for a method of creating a pressure wave by transforming power from an electrical discharge to a mechanical impact. They derived more than 200 applications for technical and industrial processes.In the 1970s, civil engineers at the Engineering and Building Institute in St. Petersburg, Russia, began to look at EHDE to improve the capacity of drilled piles. Early experiments showed that electric discharges in a wet concrete slurry mix could create a pressure wave of up to 26 MPa (3700 psi). Later tests demonstrated that this pressure level could be created in a drilled pile hole. The researchers devised equipment and in the early 1990s began to study pulse technology as applied to drilled piles.This application was accepted into the Russian Federation Building Code in the 1990s. The code treats “regular” drilled piles with equivalent bearing area as having roughly half the capacity of a driven pile. However, the code considers drilled piles treated with the EHDE technique a direct “one for one” substitution for driven piles and allows higher values if the capacity is established by static load testing. Hundreds of projects have been completed in Russia using this technology to value engineer drilled pile projects. In several instances, the number of drilled piles installed was fewer than half of the number originally planned for due to the capacity increase that EHDE-treated piles provided.Drilled PilesIn drilled pile construction, the EHDE process creates a mechanical pressure wave that impacts the base and sidewall of a drilled pile shaft. Soft, poorly consolidated or loose soil is compacted by successive pulses of pressure created by electrical discharges. These mechanical impulses are made by inserting a discharge probe into the wet concrete slurry. A discharge across the tip of the probe creates the pulse that travels outward to the sidewall and base of the drilled pile through the incompressible medium of the slurry. The power pack ratings for equipment presently in use are 35 and 50 kJ (kilojoule).Each pressure wave strikes the soil, causing compaction and expanding the hole. Workers apply the pulses until the size of the hole stops increasing. They watch the slurry level during pulsing. When the level quits dropping, further soil compaction in the drill hole sidewalls and base is not possible. After the pulse process is complete, workers insert a rebar cage and the pile is finished.The process does not alter the soil mineralogy. The electrical discharge is internally grounded and does not arc to the sidewalls of the drill hole. Soil is not scorched or altered in any manner; it is only compacted by the pressure wave. This technique has been used in urban areas with no effect on electrical or electronic equipment."

Jan 1, 2009

By John R. Goode

"The year 2011 witnessed a major surge in rare earth prices as China, supplier of +95% of the world’s rare earths, reduced export quotas and increased export taxes and duties. In response, companies around the world are scrambling for alternative sources. In Canada too, there is a race to be the “first” rare earth producer. Something that is not generally realized is that Canada has a long history of rare earth production and was a major supplier from the early 1960’s to 1990. At one stage, Canada was said to be supplying more than one third of the world’s yttrium and probably supplied even more than that. Five decades ago, thorium was a key element in many non-nuclear applications and Canada became a major supplier of thorium from the late 1950’s to 1968, first as a by-product of uranium and then as a co-product of rare earths. This paper reviews the development of Canada’s original rare earth and thorium production facilities, which were located in the Elliot Lake uranium camp in Northern Ontario. The uses of these elements, geology, mineralogy, markets of the time, and processing are all discussed. Some of the lessons learned from these pioneering operations might be useful in today’s race to develop the next generation of rare earth production plants.INTRODUCTION The rare earths and thorium were first identified in the early 19th century but were little more than curiosities for the next century. However, in the mid-1960’s the invention of rare earth-based phosphors for the cathode ray tube in colour television sets launched a major demand for certain rare earths. The use of thorium as an alloying agent in aircraft and missiles grew rapidly in the late 1950’s. In the same period, demand for uranium for both weapons and power production soared. Also in the late 1950’s, the Elliot Lake uranium-thorium-rare earth deposits (also known as the Blind River deposits) were discovered. This conjugation of events led to uranium production in the Elliot Lake camp, quickly followed by the co-production of thorium and, later, the rare earths. Uranium production in the Elliot Lake camp continued from 1955 to 1996. Thorium was produced continuously from 1959 to 1969. Rare earths were produced, intermittently, from 1965 to 1990. Complete production records are not readily available for thorium and the rare earths but unquestionably Elliot Lake production made a significant contribution to world production. This paper is intended to present as much of the information that is available."

Jan 1, 2012

By Timothy C. Richmond

The Stillwater District is located in south central Montana approximately 75 miles southwest of Billings, the state's largest city. It lies along the northeast front of the Beartooth Mountains and is within the boundaries of the Custer and Gelatin National Forests. The district contains some of the nation's most spectacular mountain scenery. Montana's highest peaks, including 12,799 foot Granite Peak, rise a few miles south of the area. Much of the district is located on a gently undulating plateau which averages 8500 ft. above sea level, broken by hills up to 10,000 feet and slashed by glacially carved canyons, some of which are more than 3,000 feet deep.(Fig. 1) Immediately to the north and east, the land falls away to the Great Plains, stretching unbroken to the Mississippi River. Two major tributaries of the Yellowstone River, the Stillwater and Boulder Rivers, traverse the area and several large streams originate in the district itself. Access to the high mountain country and the adjoining Beartooth Primitive Area is restricted to a few horse and jeep trails continuing from the terminus of improved roads in the bottom of the Stillwater and Boulder Valleys. Hunters, fishermen and cabin owners make intensive use of the area along its improved transportation routes, but hikers seldom venture more than three miles beyond the end of the roads. People from the Billings area are the most frequent visitors.

Jan 1, 1974

By E. Engelbrecht

"A pressure non-oxidative leach is employed at Anglo American Platinum Base Metal Refiners to extract nickel from a slow cooled matte. The design base requires two 80 m3 autoclaves in parallel to achieve a nickel extraction of 60% at the nameplate capacity of 32.4 ktpa nickel plated. Isothermal modelling of mineralogical and chemical concentration profiles, through a reactive mass balance, permitted rate constant parameter estimation and selection of the most probable reaction pathway. The model was validated with plant data up to a capacity of 26 ktpa Ni plated and suggested by extrapolation that nameplate capacity may be viable through one 80 m3 autoclave.INTRODUCTION Anglo American Platinum Base Metal Refiners is situated on the outskirts of Rustenburg in the North-West province of South-Africa. The refinery produces nickel cathode, copper cathode, cobalt sulphate powder, covellite rich copper pressure leach residue and bulk sodium sulphate through an integrated circuit that refines slow cooled converter matte. The converter matte is milled, non-magnetics are separated as solid nickel copper matte (NCM), and the magnetics are leached yielding a pressure vessel liquor (PVL). The remaining solid platinum group metals (PGM) concentrate after leaching is sent for downstream processing in the Precious Metals Refinery (Hofirek & Kerfoot, 1992). The work presented here is applicable to the base metals refinery which receives the two base metals feed stocks NCM and PVL. In 2009 the capacity of the refinery was upgraded from 21 ktpa nickel cathode plated to 32.4 ktpa. This paper deals with evaluating the capacity of the pressurised non-oxidative nickel leach (NOX) process which accounts for at least 28% of the nickel leached from NCM by design. The NOX design base requires two 80 m3 autoclaves divided into four compartments operated in parallel at 155°C and 600kPa(g). Elevated temperature is required to speed up the leach kinetics of particularly nickel and iron which are trapped in slow leaching mineralogical phases namely millerite and bornite, (Dinham, 2006). The stated equivalent capacity for the NOX configuration was 32.9 ktpa nickel plated at first pass nickel and iron leach efficiencies of 60% and above 80% respectively and is a key step for the selective removal of iron (Bryson, Hofirek, Collins, Stiksma, & Bereaowsky, 2008)."

Jan 1, 2017

By Ray Holmes

This paper describes one approach in our search for greater stope efficiency and lower costs. The uppers technique with wagon drills in cut-and-fill stopes was commenced, on an experimental basis, in our Sudbury mines in 1961. To date, the method has developed into an accept-ed production operation. This technique minimizes the intermittent aspects of the drilling, blasting, mucking and filling operations associated with other cut-and-fill methods. However, studies show that not all cut-and-fill stopes are suitable for uppers, the governing factors being ore width, dip of the orebody, and ground conditions where large areas of unsupported back remain stable for ex-tended periods of time until rockbolting can be accomplished. Introduction F ALCONBRIDGE Nickel Mines Limited operates seven mines within a radius of 30 miles of the city of Sudbury, Ontario. These mines extend in depth from 1,500 to 6,300 ft. The ore consists of brecciated, massive and disseminated sulphides, and the ore minerals consist primarily of pentlandite, pyrrhotite and chalcopyrite. Widths are generally irregular and vary up to 150 ft. The ore dips at between 35 and 90 degrees.

Jan 1, 1965