Search Documents

By P. R. A. Andrews

"Garnet occurs in schists and gneisses in all provinces of Canada, all mainly in Quebec and Ontario. There is currently a renewed interest in exploration for economic sources of garnet for abrasive applications because of the inherent dangers from exposure to ground silica from sandblasting operations.High-quality garnet is used for lapping and grinding of glass and ceramics; for coated and bonded products such as sandpaper and cloth; and abrasive wheels for grinding and finishing various metals, woods, rubber and plastics. Low-quality garnet is used for cleaning and conditioning aluminum and other soft mewls, particularly by aircraft manufactures. Garnet may be added to grouting cements for oil-well drilling applications, and it has also been used for low- to medium-level radiation shielding. Garnet has been studied extensively by CANMET and its predecessor, Mines Branch, between 1917 and 1990. Twenty-nine studies relating 10 various aspects of beneficiation are presented and a review of the more important studies is presented. The information includes mineralogy, beneficiation methods, product sizes and analyses."

Jan 1, 1995

By John J. Jonas, Hong Qin

Cylindrical samples of pure titanium were subjected to uniaxial compression at room temperature, leading to the formation of three generations of twins. Many primary contraction twins were observed as the initial texture was favourable for their formation. Numerous secondary extension twins formed within the primary contraction twins and some tertiary contraction twins within the secondary extension twins. The orientations of these three generations of twins were determined by electron backscatter diffraction techniques and their associated Schmid factors (SFs) were calculated. The formation of the twin variants selected in each generation and the absence of certain potential variants are accounted for by rotating the twinning displacement gradient tensor expressed in the twin system reference frame into the crystallographic reference frame of the relevant neighbouring grain. The presence of the observed primary, secondary and tertiary twins is explained in terms of the ease of imposing the required accommodation strains on the neighbouring grains. By contrast, certain first, second and third generation potential high SF twins were absent because their formation would have required accommodation by the most difficult deformation mode: pyramidal glide.

Jan 1, 2015

By Craig H. B. Leitch

"In describing the alteration of porphyry systems, the term ""secondary K-feldspar"" appears to be an oversimplification. A better term would be ""alkali feldspar"" alteration, because in actual fact the replacement feldspars show gradational changes from an albite, which is important in some systems, to an alkali feldspar containing minor orthoclase molecule, to true orthoclase.There are several textural varieties of secondary alkali feldspar present in the porphyry systems studied from British Columbia, Australia and New Zealand. These include, in apparent increasing order of alteration intensity: clear albite (An10); patchwork albite (An5-10); chessboard albite (An0-10); ""irregular albite "" (An0Ab100 to Ab90Or10); untwinned ""anoralbite"" (Ab90Or10 – Ab70Or30); and orthoclase (Ab40Or60 - Or100)·The exploration significance of these varieties of alkali feldspar is that their gradation in composition, from sodic to potassic, may be linked to a corresponding increase in intensity of alteration. Thus, there is a tendency for more sodic alteration feldspars to characterize weak, sub-economic deposits, or the fringe zones of stronger deposits; the more potassic alteration feldspars may provide an exploration vector toward more highly mineralized zones."

Jan 1, 1981

By Jef M. van der Zel

The idea of veneering rich yellow gold alloys with a low-melting, high expansion porcelain, has been a driving force for metal-ceramic research in dentistry. Since 1990, with the advent of the Carrara System (1), a low firing temperature veneering ceramic allowed the use of gold alloys with a lower content of platinum and palladium than the traditional gold-platinum ceramic alloys and thus a richer yellow color. The earlier high gold-platinum ceramic alloys contained at least 12 percent platinum group metals to allow for dimensional stability when firing the relatively high melting traditional ceramics. This amount of platinum group metals gave the alloys a greyish tinge which made them unattractively steel colored and difficult to present as ?high gold alloys?. In the 90?s the new generation universal low-melting, high expansion gold alloys gained market share at a steady rate, starting in Germany, and have now for a great part replaced the traditional gold-platinum alloys (Fig. 1). The first alloys contained 75 wt-% gold and up to 9 wt-% platinum or palladium. They provided a metal-ceramic system in which a gold alloy having an aesthetic yellow colour is fired on with a dental porcelain tailored thereto. The tailoring is meant in respect of compatible coefficients of thermal expansion, and compatible melting or softening points of metal and porcelain. The major concerns in the beginning were with thermal stability during firing, the thermal expansion coefficient of the alloy against the porcelain (compatibility) and the yellow color. In a later stage, alloys with gold contents in the range of 50-60 wt-% gold were developed in analogy with the pale yellow gold-reduced alloys that were formerly used for crown & bridge work and the white gold-reduced alloys used for metal veneering where gold was substituted in part by palladium.

Oct 1, 2003

By W. A. Jones

THE Ross mine, a subsidiary operation of Hollinger Consolidated Gold Mines, Limited, is situated near the north end of lot 1, concession 2, Hislop township, Ontario. The property comprises the north half of lot 1, concession 2, and the south one-third of lot 1, concession 3. It is readily reached by a good motor road from the village of Ramore, 7.5 miles to the southeast on the Temiskaming and Northern Ontario railway. The-mine has been developed to a depth of 900 feet and the current daily production rate is about 260 tons. From the inception of operations in March, 1935, until December 31st, 1942, 455,720 tons of ore with a total value of $4,169,-316 have been milled. The silver to gold ratio of 1.48 to 1 is unusually high for Ontario gold mines. The deposit is interesting because the relationship between hydrothermal metamorphism and three successive stages of fracturing and mineralization is marked with considerable clarity. During the past seven years, detailed geological maps of the mine have been kept up to date, many thousands of feet of diamond-drill core have been logged, and numerous thin and polished ore sections have been studied. The present paper describes the structure and mineralogy of the orebodies.

Jan 1, 1944

By Richard S. Allen

"The casual visitor is not apt to think of the Adirondacks as a one-time hive of mining and manufacturing activity. However, where there are mountains there are usually minerals and northern New York State is no exception.The Adirondacks are a rocky shield, a great stone cap pulled down over what is now northern New York. The bedrock consists of layered metamorphic rocks which were once sandstones or limestones on the bottom of a shallow sea that covered the region 1000 million years ago. The highlands are composed for the most part of the igneous rock anorthosite. Ancient earth upheavals at temperatures of at least 750°C mixed molten masses of anorthosite and the minerals it contained with the older metamorphic rock, resulting in deposits of iron-titanium oxide s, red garnet and other valuable minerals. Of these, the most readily recognizable was iron.The first hint of the existence of iron ore in the Adirondack Lake Champlain region of upper New York State seems to have come from a Swedish naturalist, Peter Kalm (1716-1769), who travelled through French Canada and visited the military outpost of Fort St. Frederic in 1749. In July of that year, Kalm wrote:""Among the kinds of sand which are found on the shores of Lake Champlain; one is black and the other garnet-colored... and they sparkle when the sun shines. All the grains of this sand without exception are attracted to the magnet, the uppermost or black sand being about a quarter inch deep...""Concerned primarily with the fur trade, the officers and men who occupied this remote bastion of La Belle France were apparently unaware of the industrial and commercial possibilities beneath their feet. No deposit of iron was then known to exist any closer than the Three River s area in Lower Canada."

Jan 1, 1983

By S. Haggarty

"Wholly owned by Corona Corporation, the Nickel Plate Mine is an open pit, gold mining operation located near Hedley, 50 km west of Penticton, in Southern British Columbia.Milling capacity is 3,400 SDT /Day with an average feed grade of 0.080 Oz Au/Ton. Gold processing involves three stage grinding including tertiary pebble milling, two stage cyanide leaching and filtering and Merrill-Crowe zinc precipitation.A summary of process improvements required to increase milling capacity above the initial design tonnage of 2, 700 SDT /Day are described -Installation of a 42"" x 65"" Allis Chalmers Gyratory crusher replacing a 42"" x 48"" Traylor jaw crusher.Installation of polyurethane screen panels replacing woven wire cloths on an 8' x 20 ft triple deck screen.Installation of a hopper clarifier to reduce filtrate turbidity.Automated control of solution balancing and effluent treatment circuits.INTRODUCTIONThis paper describes mining and milling practices at the Nickel Plate Mine and details post start-up process modifications which were required to attain design tonnage.Wholly owned by Corona Corporation, the Nickel Plate Mine is an open pit, gold mining operation located near Hedley, 50 km west of Penticton, in Southern British Columbia.Mining capacity from the open pit is approximately 32,000 TPD with an average waste/ore ratio of 8.4:1.Milling capacity is 3,400 SOT/Day, above initial design tonnage of 2,700 SOT/Day. Feed grade averages 0.08 Oz Au per ton yielding 85,000 troy ounces of gold per year."

Jan 1, 1991

By Jan Butra

Longstanding mining of copper deposits in the Legnica-Glogow Mining Basin, Poland has accumulated broad experience concerning the impact of geological and mining conditions on seismic and rockburst hazard. Methods of rockburst prevention for deep copper mines have been developed based on gathered data. Methods of rockburst hazard evaluation and rockburst control constitute a set of rockburst prevention measures. Due to their nature and location within the production process, prevention methods can be passive or active. Active methods of rockburst prevention consist of the liquidation of stresses in the areas where they are concentrated through controlled generation of rock-mass tremors and rockburst by blasting works (group extraction blasting, release blasting in the rock mass and pillars able to accumulate the stress, as well as in the roof and floor). Group blasting works as a basic method are very effective in copper mine conditions. Provocation of dynamic events makes it possible to control the timing of their occurrence. In Polish copper mines, all blasting works are made during the absence of miners in the mining fields. Daily distribution of both the number of recorded strong seismic events and volume of energy released, confirm the advisability of using this kind of rockburst hazard prevention. The rockburst hazard prevention methods developed over 40 years of copper deposit extraction are economically reasonable and offer sufficient effectiveness under high rockburst hazard conditions.

Aug 1, 2013

By D. C. Carter, J. P. Anderle

"Exploration drilling of evaporite sequences in eastern Canada has undergone significant changes in equipment, techniques and philosophy since the early 1970s. The result has been the recovery of full-size cores from properly conditioned and stabilized holes, high quality open hole geophysical logs, and high quality metallurgical samples. The majority of modifications have resulted from the necessity to preserve the integrity of the evaporite deposit, and thus ensure the potential development, combined with the need for cost-effective high quality information. This is particularly evident in the priority placed on the development of non-erosive drilling fluids, casing and cementing procedures. The results are applicable to diamond drilling exploration of evaporite deposits anywhere in the world.IntroductionThe majority of current technical and scientific literature and expertise available on such subjects as drilling fluids or cementing procedures is applicable to large diameter, deep (several thousand metres) oil-field type drilling . The differences between oil-field drilling and wire-line core diamond-drilling are dramatic: large diameter, deep holes drilled with a low rpm tricone bit using large volumes of fluid pumped through a large annulus versus small diameter, shallow (less than 600 m) holes drilled with a high rpm diamond-set core bit using small volumes of fluid pumped through a small annulus. Exploration drilling of evaporite sequences in eastern Canada in the early I970s was conducted using oil-field equipment and techniques to complete holes of moderate (1000 m to 1500 m) depth . The prohibitive cost of these operations has necessitated that subsequent exploration drilling employs modified diamond-drilling equipment and techniques developed as part of a transition away from oilfield methodology. The result has been full size core, recovery approaching 1000/0 and the ability to run open hole geophysical logs; a combination of factors enhancing the collection of high quality information (Carter, I989a)."

Jan 1, 1990

By R. P. Charbonnier

"To understand the operation of jigs and other separating processes based on differences in gravity, it is desirable to analyse the motion of various particles in given media under specific conditions. A summary of the earlier theories shows that they lead to unsatisfactory or excessively complicated formulae in cases such as coal jigging. By adopting a simplified theory of the motion of particles in a fluid, the size and duration of the initial accelerated motion of a particle falling in hindered settling can be calculated. Based on this mathematical analysis, examples referring to actual coal jigging practice show that it is desirable to prolong and/or repeat, as frequently as possible, the optimum conditions corresponding to an effective acceleration of the particles. The separation is then obtained according to gravity rather than to particle dimensions, as would be the case if the velocity of the particles• were allowed to approach its terminal value. To achieve this gravity separation, it is suggested that the suction phase of the jigging cycle be artificially prolonged and the frequency of pulsations increased as much as possible for washing the coals of smaller sizes."

Jan 1, 1959

By Mike Power

Geophysical techniques have played a pivotal role in northern kimberlite exploration since the initial discovery at Point Lake in 1991. In the Slave Craton and surrounding regions, there are definite contrasts in physical properties between kimberlite intrusions and surrounding bedrock. Kimberlite commonly displays higher magnetic susceptibility, distinctive remnant magnetism, low electrical resistivity and lower density than surrounding rocks. In addition, the distinctive geometry of kimberlite pipes is reflected in geophysical responses which further facilitates target discrimination. There has been an evolution in geophysical exploration strategies over the past 12 years. Helicopter total magnetic field and electromagnetic (HEM) surveys have proven to the most cost-effective means of conducting first pass investigations in prospective areas. During the early 1990's, total magnetic field and frequency domain electromagnetic surveys were virtually the sole techniques employed during follow-up surveys. Inevitably, the initially high rates of kimberlite discovery declined in the areas surrounding the original finds. Marginal magnetic and EM anomalies were all that remained to be tested and this spurred interest in the improvement of existing interpretation algorithms and in the application of additional complementary techniques to reduce the exploration risk. Gravity has become a popular third survey following the deployment of the Falcon (TM) airborne gravity gradiometer system by BHP Billiton in 1999 and improvements in ground techniques. Ground penetrating radar (GPR) has proven to be particularly useful in delineating kimberlite pipes following drill discovery and in exploring for kimberlite dykes in settings where indicator mineral trains indicate such targets are likely. Seismic methods have been tested for both reconnaissance and delineation but remain underemployed. Given the high cost of drilling in the North and the proven success of geophysical techniques in reducing exploration risk, it is likely that an increasingly diverse range of geophysical techniques and innovative interpretation techniques will continue to be applied in kimberlite exploration.

May 1, 2003

By D. M. Maijer, S. L. Cockcroft, A. B. Phillion, P. Fan, C. Reilly, H. Khadivinassab

A combined experimental / numerical approach is proposed to investigate the bulk transfer of solute due to liquid metal feeding during shape casting of aluminum alloy A356 (Al-7Si-0.3Mg). A dumbbell-shaped experimental casting geometry has been developed, which promotes solute redistribution due to liquid metal feeding. The redistribution of solute in trial castings is evaluated based on the area fraction of eutectic phases. In the numerical model, silicon species segregation during solidification are calculated assuming the Scheil approximation, and are coupled with macro-scale solute transport due to Darcy flow in the mushy zone and feeding flow. The model has been implemented within the commercial CFD software, FLUENT, which simultaneously solves the thermal, fluid flow fields and species segregation on the macro-scale. The experimental and numerical results are compared and contrasted to examine the effects of liquid metal feeding in this casting.

Jan 1, 2014

By W. A. Grell

"The oxygen meter has been in use at MacLeod Cockshutt Gold Mines for over a year, At MacLeod about 200 tons per day of reground concentrate containing roughly 10% pyrrhotite and 20% pyrite is cyanided in four 181 x 18' Dorr agitators. A survey by the Department of Mines showed that oxygen content of some of the agitators was rather low. Experience with our oxygen meter indicates that the oxygen content must at times have been too low for good gold dis solution.We have found that in winter, when pulp temperatures drop to about 50° F, oxygen saturation in the agitators is not difficult to maintain. In summer, however, when pulp temperatures rise to 70or 75°F, the oxygen content will drop very readily. It was found that a high oxygen content can be maintained readily if the pulp is sufficiently dilute. Thus at 50° F, a pulp of specific gravity 1. 75 i.e., about 55% solids, will saturate; but at 70 or 75° F, the specific gravity must be decreased to 1 .45, equivalent to about 40% solids, in order to maintain saturation. Very thick pulps, such as thickener underflows, are noticeably difficult to saturate in the laboratory, and lose their oxygen rapidly.Clear solutions, on the other hand, absorb oxygen readily and hold it. The primary thickener overflow, before agitation, is 100% saturated; after storage of 3 to 4 hours it is still 100% saturated at re clarifier tank. Barren solution after spraying in a launder is 100% saturated.We have not yet attempted to determine what percentage saturation is necessary for good extraction, but it is known that there is a point at which extraction decreases rapidly. So far, the measures required to maintain over 80 or 90% saturation have coincided with measures required to hold the reducing power to the point believed necessary."

Jan 1, 1964

Resistance spot welding is the most common type of welding in the automotive industry. In RSW the size and shape of welding nugget is one of the most effective factors on mechanical properties, such as tensile shear strength and fatigue strength. so properly adjusting the variables of the welding is necessary .in this study the effect of different parameters of RSW including time, current, electrode force, geometry of electrode so diameter and angle of electrode tip in the shape and size of welding nugget evaluated. for experimental procedure, low carbon steel sheet st12 is used. the process is simulated with finite element method by using ANSYS software. for the formation of welding nugget a 2 dimensional symmetrical model electrical-thermalmechanical is used and for elevate the accuracy ,we determined the properties of material related to temperature. The results show that increasing the time and current of welding, the diameter of spot weld also increased and the role of current is more impressive. and also increasing the electrode force decrease the diameter of the nugget due to increasing the contact area and decreasing the resistance .increasing the diameter of electrode tip cause increasing contact area and decreasing the resistance and decreasing the diameter of the nugget. furthermore, changing tip angle and electrode diameter don't show sensible change in the geometry of the welding nugget. comparison between simulation and experimental result show a good adaption.

Oct 1, 2011

By P. E. Auger, J. E. Gill

"The zinc deposits to be described are in Lemieux township a few miles south of the Tabletop mountains, in the central part of Gaspe peninsula, Quebec. Although they have not been worked, they constitute a potential source of zinc and lead and structurally are of considerable interest.GENERAL CHARACTER OF THE OCCURRENCEThe deposits are in sharp-walled quartz-carbonate veins and breccia zones carrying locally, and in varying amounts, sphalerite, galena, pyrite, marcasite, chalcopyrite, and specularite. Those so far investigated strike generally north-south, have steep dips, and cut through sediments of Lower Devonian age, mostly calcareous argillites or siltstones. Wall-rock alteration is negligible.BROADER STRUCTURAL FEATURESThe principal known occurrences are in the south-central part of a dome structure measuring 6 by 5 miles. The argillaceous sediments are overlain, on the flanks of the dome, by sandstones and lavas. These have been stripped from the central part of the dome, revealing the veins in the argillites beneath. The veins formed after the volcanics, but the fractures and breccia zones in which the deposits formed are confined mainly to the argillite series, presumably because of the greater strength of the lavas.The argillite series is cut by dykes, sills, and small stocks of diorite and acidic 'porphyries' that are older than the veins.THE FEDERAL HILL AREAThe distribution of known veins is shown in Fig. 1. The characteristic features of the veins are well illustrated by the Federal Hill area shown in Figs. 2, 3, and 4, and described below."

Jan 1, 1954

By R. Gatzweiler

The Key Lake nickel-uranium deposits are situated within the Wollaston domain of the Churchill structural province. The host rocks of the two orebodies are of Aphebian and Helikian age. The orebodies occur mainly within a 5.2-km-Iong, northeast-trending zone which coincides with the intersection of the sub-Athabasca unconformity and a reverse fault striking east-northeast. The principal controls of mineralization are structural and lithostratigraphic (i.e., post-Athabasca faults, the sub-Athabasca unconformity and graphitic metapelites in the lower Aphebian, close to the Aphebian/Archean unconformity). Grades of up to 35% U3O8 and 20% Ni are recorded over intervals of up to 2 m. Some hypogene zonation exists and the nickel mineralization tends to underlie the high-grade uranium ore. The ore minerals include pitchblende, a-U307, coffinite, gersdorffite, millerite, niccolite, bravoite, zoisite, sericite, chlorite and kaolinite. The kaolinite is a post-ore, supergene alteration product. Chemical studies of the sub-Athabasca paleo weathering profile sho w that regolithization is characterized by depletion in Si02 and K20 and concomitant enrichment in Al203 and perhaps MgO. In the paleoweathering profile the ferromagnes ian minerals are chloritized, the Ksfeldspars sericitized and the plagioclase saussuritized. Preliminary geochronologic data from the ores reveal U/Pb ages of -1228 my, - 960 my and 89 my, and Rb /Sr data indicate basement ages of -1850 my and - 1372 my. Aphebian pelitic protoliths, carrying U and Ni, may have released some metals during post-Hudsonian weathering, and minor concentration in structural and geochemical traps may have taken place prior to the deposition of the Athabasca strata. However, it is felt that the bulk ofthe ore-grade mineralization wasgenerated after the deposition of the Athabasca formation and after faulting, probably during a major regional thermal/ intrusive episode of Grenvillian age. Several episodes of remobilization took place between 1228and 89 my ago.

Jan 1, 1979

By F. F. Roberto

Sulfuric acid has been demonstrated to be an efficient lixiviant for in situ extraction of copper in the past. It has also been proposed that microbial production (by iron-oxidizing acidophilic bacteria) of acidic ferric solution either in situ or ex situ could provide an economic strategy to generate an effective lixiviant for secondary copper sulfides like chalcocite and covellite. Copper heap bioleaching also takes advantage of this approach. One of the major environmental challenges for in situ copper recovery projects is the containment of acidic solution within the ore deposit, and ultimate restoration of the depleted ore body to its original state. A perhaps overlooked aspect of projected site operations is the possibility that transient acidic conditions and pumping of solutions from surface reservoirs into the subsurface could stimulate the growth of iron- or sulfur-oxidizing species of acidophilic microbes in the ore body, leading to additional generation of sulfate, acid, and ferric iron. This outcome would benefit extraction of copper in mixed oxide/sulfide deposits in the near term, but could complicate restoration activities. Possible impacts of pumping acidic solutions into the subsurface on microbes resident in, or introduced into the extraction zone will be discussed in the context of our understanding of copper heap bioleaching and acid rock drainage. INTRODUCTION As high-grade deposits of metals such as copper continue to decline, conventional mining methods have evolved to mine and process larger and larger quantities of ore. What is currently defined as ore today often contains less metal than the tailings of past operations. The throughput of current-day mines also leads to tremendous amounts of waste rock and tailings that may threaten the environment and communities around the mines, as has recently been experienced by 3 major tailings disposal facility (TSF) dam failures in the past 5 years. Community acceptance of large mine operations thus becomes more difficult to achieve—loss of the social license to operate. In response, the mining industry urgently pursues innovations that can fundamentally change the way in which metals are mined. In situ recovery (ISR) of metals represents one approach to a more sustainable mining industry, by virtually eliminating the need for a pit or underground excavation, eliminating the excavation and transportation of ore to a process plant and the ensuing noise and dust that is generated, and any need for waste rock dumps or TSFs. An ISR mine could have very little visible footprint beyond a network of wells, pumps, and piping to transport pregnant solution to a recovery facility, such as a solvent extraction- electrowinning (SX-EW) plant for copper. Some solid waste streams and/or storage ponds may still be necessary to treat and store bleed streams, PLS and raffinate, or as part of groundwater restoration activities. Thus capital and operating investments would be potentially much lower than that required for a conventional mine. In theory production could also be controlled to adjust to subsurface ore grade and match market demand. A not insignificant challenge of in situ recovery is the requirement for an efficient, low-toxicity, and ideally selective lixiviant for the metal that is targeted.

Jan 1, 2019

By N. Shi, T. G. Joseph

ABSTRACT: An interactive cable shovel simulation has been developed to mimic any shovel dipper geometry for a given cable shovel operating in any homogeneous face material. This interactive cable allows the user to predict shovel performance in any face material encountered and track both its ground stability and the dipper-ground interaction. An embedded Microsoft® Visual Basic spreadsheet was used as the platform for developing an interactive simulation that allows for maximum user-defined parameter input and interactive visual output. The result is an analytical dipper-ground interaction solution that yields crowd, hoist, and digging effort as a function of face activity position.

Jan 1, 2011

By Janet S. Springer

Anomalous gold concentrations in carbonaceous material have given rise to misconceptions about the role of carbon in gold depo its. Some hydrocarbon and carbon-rich black muds may how gold contents raised to 100 time above background by mechanical entrapment. urface effect in fine ediments. and metabolic fixing of gold by micro-organisms. Such concentrates, however, are 10 times too low to be economic. Studie in the Archean of Ontario show that graphite schi t are not the protore to an economically workable gold deposit. A later event of gold introduction ha been uperimposed on the initial low concentrations. Gold enrichment i localized by reduction at vein margins where hear plane . the conduits of mineralization, cut carbonaceou horizons.

Jan 1, 1986

By R. A. Parra, Fuentes, C. Godoy, L. E. Arias, C. A. Toro, M. Marin, E. Balladares, V. Parra, G. Reyes, S. N. Torres, D. Sbarbaro

In this paper, we report on the detection of spectral molecular emission of iron oxide (FeO) and copper oxide (CuxO) emitted by reactions occurring in a laboratory scale flash smelting process of pyrite (FeS2) as well as copper concentrate. The novelty of the technique is that, the molecular spectral emission sensing is achieved by using a low spectral resolution and low sensitive radiometer, enhanced with signal processing and matrix factorization techniques. The method was validated using a highly sensitive spectrometer, with a high spectral resolution; achieving a similar FeO spectral pattern as the one obtained after signal processing techniques over low resolution spectral signals. INTRODUCTION Visible-near infrared (VIS-NIR) spectroscopy is an optical contactless sensing technique commonly used to capture information about the emitted, absorbed, transmitted or scattered radiation in a physical or chemical process, with the presence or absence of an excitation light source such as a laser or a broad spectral band source. These techniques coupled with signal processing and machine learning algorithms, sometimes referred as chemometrics (Pisapia et al., 2018), can be found in processes such as: pharmaceutical (Kandpal et al., 2016); food (Coelho et al., 2016); combustion (Ballester & García-Armingol, 2010); siderurgy (Strakowski et al., 2014) industry, among others. In the extractive copper industry there are several technological developments using optical sensing techniques aimed to retrieve information about copper ore and concentrate mineralogical composition such as X-Ray Fluorescence, Qemscan® (Quantitative Evaluation of Minerals by Scanning Electron Microscopy) and X Ray Diffraction (XRD) analysis, however, because of the manual procedures to analyze the samples with these laboratory instrumentation, only discrete information during a daily based operation can be retrieved, making impossible for the operators to take decisions over the involved processes in real time. The aim of our research work presented here is to contribute with sensing and data analysis procedures based on VIS-NIR spectroscopy for the flash smelting process characterization, particularly in this paper, with the detection of FeO and CuxO molecular emissions in a laboratory scale setup.

Jan 1, 2019