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By B. Drew, K. Budna, C. Wenzl, D. Gregurek, A. Spanring

"The metallurgy of nickel and cobalt and of copper is closely interlinked when processing sulfidic Ni-Co ores and Cu-Co ores. The respective furnaces are typically lined with magnesia-chromite refractories, which are exposed to multiple and complex stresses. The selection of the processing route, furnace type and slag system will be dictated by the specific ore type available, this will determine the individual refractory wear mode. This paper evaluates the common refractory wear mechanisms, namely infiltration, spalling and chemical attack by various slag systems, as well as sulfur attack, as observed when processing primary sulfidic ores. All these wear parameters, which are discussed in this paper, lead to a severe degeneration of the brick microstructure and a decreased lining life. Therefore, a detailed investigation and understanding of the wear mechanisms through “post mortem studies” is an important prerequisite for the refractory producer. Based on such research results, combined with specific process knowledge, appropriate brick lining solutions for nickel and cobalt processing furnaces can be recommended.INTRODUCTION The metallurgical production of cobalt and nickel and of copper is closely interlinked to the mineralogy of the respective ores: cobalt is found in African Cu-Co ores as well as in Co-rich nickel ores (laterites and sulfides). Also, Co-bearing secondary raw materials contain the mentioned elements in different contents. In pyrometallurgical processing of sulfidic ores, cobalt is generally recovered as a by-product during the production of copper and nickel, whereas it is normally not recovered separately during the processing of nickel laterites but remains in the FeNi product. Besides various hydrometallurgical production routes, the pyrometallurgical processes involved comprise smelting (i.e., production of a Cu-Ni-Co-Fe matte in electric or flash furnaces), converting and refining (i.e. removal of Fe and S as well as other elements from matte by oxidation). The ongoing trend to use higher oxygen enrichment in process air enables higher intensity processes but also increases the oxidation potential in the vessel. Therefore, during smelting and especially during the oxidative treatment in converting and refining, some amounts of valuable metals are also transferred to the slag in their oxides form. A subsequent slag treatment is then applied for recovering valuable metals from the slag, namely allowing an economic material stream handling and minimizing metal losses. This is often done in a slag reduction furnace. Additionally, copper and nickel are very good collectors for precious metals and platinum group metals (PGMs) - therefore, depending on the content of these metals, an additional refining process is used to recover these valuable metals from the matte or metal phase (Elvers et al., 1997; Davenport et al., 2002; Crundwell et al., 2011)."

Jan 1, 2017

By H. C. Gunning

SOME small vanadium-bearing deposits on the west coast of British Columbia about 100 miles north of Vancouver are of interest for several reasons. They are of a type that is, so far as we know, unique. They are difficult to identify as being vanadiferous so that, unless they are described, other similar deposits could easily pass unrecognized. Furthermore, although none of them has as yet been proven to be of commercial proportions, no good reason is apparent why larger, and therefore valuable, deposits should not occur under similar geological conditions. The original discovery on Quadra island was made in 1932 and has been recorded by H. V. Ellsworth and H. C. Gunning (l). Since 1932, prospecting in the area has revealed other similar deposits, one about a mile south of the original and another some ten miles to the east, near Menzies bay on Vancouver island. The Quadra Island showings are a mile and a half north of the head of Gowland harbour, a small inlet that is easily reached by gas boat from Campbell river, about four miles to the southeast on Vancouver island. The deposits were examined by the writers in the spring of 1943 in connection with field work sponsored by the Department of Geology, University of British Columbia. We are indebted to Mr. G. A. Dirom and Mr. Lothrop, of Vancouver, for helpful data on the Menzies Bay deposits, and to Dr. V. Dolmage for making a brief trip to Gowland harbour and discussing the deposits.

Jan 1, 1944

By E. Heikkinen, J. Suikkanen, T. Siren, J. Valli, M. Hakala

Diametrically faced borehole breakout observations are a fairly good indication of magnitude of the secondary stresses acting perpendicular to the borehole. In cases of low in situ stresses, where borehole breakouts are not observed naturally, it is possible to increase the prevailing stress state around the borehole by increasing the rock temperature. When the temperature is increased sufficiently, thermally induced borehole breakouts will occur. By implementing the temperature increase in boreholes located at excavated tunnels, it is also possible to study the effect of the near-field stresses caused by the excavation. The near-field stress state changes as a function of borehole depth, thus increasing the information available from experiment. To study the feasibility of this proposed low cost method, a Borehole Thermal Spalling (BTS) experiment was executed in ONKALO Underground Rock Characterization Facility, in Western Finland in 2014. The first borehole pilot test with the method was conducted in ONKALO at the POSE niche in already at May 2010, with the second pilot test following in August 2010 at Äspö HRL. The major objective of the experiments was to define the trend of the maximum in situ stress component, while also providing knowledge of the in situ spalling strength of the ONKALO rock mass. The stress state in ONKALO is nearly isotropic in horizontal layer, causing problems for the use of more traditional stress measurement methods. With boreholes heated over long interval, the weakest rock parts are observed to fail, thus providing statistical confidence. For these reasons, continuous test sections have an advantage in ONKALO, compared to spatially limited stress measurement methods such as overcoring and hydraulic fracturing. The BTS experiment is conducted in 9 meter deep vertical boreholes located at the POSE niche, situated -345 m depth below the ground surface. The boreholes used within the BTS experiment are located in migmatitic granite, in an experiment area where the surrounding stress state and the rock strength are fairly well known. The prior knowledge of the stresses is favourable for the experiment, as it requires careful planning and iterations to determine the appropriate heating power domain. Too low heating power will not be sufficient to cause borehole breakout, while too high heating power causes breakout in all directions thus making determination of stress direction hard or impossible. The initial state of the borehole and induced borehole breakouts will be monitored using acoustic televiewer logging (ABI) and optical borehole logging (OBI) imaging techniques. Fracture mechanics modelling is used in planning of the experiment, also in back-analysis to link the observed breakout angle to stress state. Both the pilot test in 2010 and BTS test in 2014 resulted in similar borehole breakout direction. The results are in line with so called EDZ & VT1 stress interpretation, revealed the maximum horizontal component bearing the magnitude of 21.5 MPa, with the trend of 166°.

Jan 1, 2015

By G. W. H. Norman

"The La Corne molybdenite-bearing veins, discovered in 1915, lie halfway between Amos and Val d'Or near the southwest corner of La Corne township, Abitibi county, Quebec. The Molybdenite Reduction Company, which carried on operations during 1927 to 1930, sank a 200-foot inclined shaft to develop the property and produced about 22 tons of concentrntes from a 30-ton mill during 1929. Hollinger Consolidated Gold Mines, Limited, carried on further underground exploration in 1930. The Molybdenite Corporation of Canada drilled a part of the property in 1938 to 1939 and produced 1 ton of concentrates in 1938. Wartime Metals operated the property from 1942 to July 15, 1945. At this time the mill was enlarged to treat 200 tons daily. Molybdenite Corporation of Canada since July 15th, 1945, have continued the operation of this property and have revised the mill flow-sheet in order to produce both a bismuth and a molybdenite concentrate.The production for the period 1942-1946 is as follows:Total molybdenite production from the mine in the 1942 to 1946 period was about 4,127,400 lb.The La Corne deposit occurs at the northwest contact of a small mass of biotite granite with biotite schist. The form and extent of the biotite granite mass is concealed by a wide sand plain that extends northwest and west from the deposit and overlies bed-rock except in four small outcrop areas. These are spaced 1,000 and 2,000 feet apart along a narrow strip extending 5,000 feet south from the mine. The outcrops suggest that the granite must be at least 1,500 feet wide and 3,000 feet long northeastward. Where exposed in the mine workings the contact dips 70°N.W., but is not a sharply defineable feature due to the presence of numerous granite dykes and tongues in a zone of biotite schist 100 feet wide along the margin of the granite. The biotite schist in the few outcrops that flank the north and south sides of the granite strikes northeast and dips 60° to 70° S.E."

Jan 1, 1954

By Z. Y. Ma, H. Y. Yang

The process of microwave-ultrasound assisted leaching of valuable metals from copper anode slime was proposed in this paper. Design of experiments has been used to study the effect of the main leaching parameters, such as microwave power, ultrasound power and reaction time. The central composite design (CCD) was used to predict the maximum leaching efficiency of copper, tellurium and selenium. The experimental data obtained were fitted to a second-order polynomial equation, and they also were analyzed by analysis of variance (ANOVA). The 3-D response surface plots and the contour plots were applied to determine the optimal conditions. The optimum conditions of microwave-ultrasound assisted leaching process were: microwave power 834W, ultrasonic power 638W and reaction time 403s. Under these conditions, the experimental leaching efficiency of copper, tellurium and selenium were 98.88±0.56% 98.96±0.78% and 98.57±0.67%, respectively, which agreed well with the predicted values.

Jan 1, 2014

By F. Awotwe-Appiah, P. Koshy, J. Dankwah, J. R. Dankwah

This research investigates the generation of an effective carbonaceous material from waste ‘pure water sachets’ and their subsequent utilisation as reductants for the reduction of the Opon Mansi iron ore. Composite pellets of Opon Mansi iron ore and pulverised carbonaceous material generated from waste pure water sachets were heated from room temperature to 1200 °C in a gas fired furnace for seventy minutes. The reduced pellet was analysed chemically for its oxygen and carbon content using a LECO Oxygen/Nitrogen and LECO Carbon/Sulphur analysers, respectively. It was observed that nuggets of metallic iron were readily produced with the carbonaceous materials acting as an effective reductant and source of chemical energy. XRD analysis of waste ‘pure water sachets’ revealed that the polymer was semi-crystalline with peaks that were identical to those of high density polyethylene (HDPE). Gas emission behaviour of the iron ore-PWS pellet was studied in a horizontal tube furnace at 1200 °C using an infrared gas analyser; the results revealed an exhaust gas rich in the reducing gases CO and CH4 along with CO2.

Jan 1, 2015

By G. Reuben Yourt

This paper consists of two main parts. The first, under the heading Preparations, deals with suggested preparations to be carried out in advance so that loss of life might be prevented should a fire occur. The second part, under the heading Fire Procedure, deals with actual organized procedure to be followed for the preservation of life if and when a fire occurs. The writer realizes that these preparations and procedures may be to some extent applicable to only a few mines with a relatively simple vein system and that each mine would need to formulate a procedure to conform to its own particular conditions, scope, and degree of complexity. Preparations 1. - Ventilation Control The objective in ventilation control in the event of a tire underground is to keep the travelways, through which men must pass to reach surface, supplied with air not deficient in oxygen and free from gases and smoke. Without some control of the volume and direction of the main air currents flowing through the mine, the success of removing men to surface might be seriously hampered. ? This control is achieved by means of mechanical ventilation forcing air through desired airways and workings with the assistance of doors to regulate the volume and direction of the air flow. In connection with fans and doors, the possibility of short-circuiting should always be taken into consideration, as it can often nullify the value of a fan and possibly trap men in dangerous atmosphere if the short-circuiting involves the fire area. Main fans are often installed so that they can be reversed in a short time. However, fans should not be reversed unless this is found absolutely essential by those in authority. Misjudgment in this respect could cause the loss of life to men who might naturally take refuge in what they believe by experience to be a fresh air stream. Another precaution to be taken is to see that doors in airways are fastened in a fixed position so that they cannot be sucked or blown open when the fan is reversed, otherwise short-circuiting could possibly render the fan useless.

Jan 1, 1947

By N. O. Lotter

The connection between mineralogy and metallurgical performance in a plant was recognised long ago (Gaudin, 1939; Petruk, 1976; Petruk and Hughson, 1977; Cabri, 1981; Petruk and Schnaar, 1981; Kinloch, 1982; Peyerl, 1983, Baum et al 1989 for example). The modern toolbox that we now routinely use for flowsheet development took decades to develop (Lotter et al., 2002; Baum and Lotter, 2004; Lotter, 2011 for example). Many workers contributed considerable time and effort to this overall mission of connecting sampling, mineralogy and mineral processing to integrate the flowsheet development activities. Certain key milestones marked this journey, such as Gy’s treatise on the sampling of particulate materials in 1979, which was later added to by François-Bongarçon, Pitard, Minnitt, and Holmes for example. The development of QEM*SEM by Gottlieb et al. of the MLA by Gu et al. constituted a huge leap forward in accuracy and mineral measurement capacity, as well as a reduction in standard errors of mineral characterisation. The advancement of the microprobe to an automated platform made a significant difference to detailed compositional mineralogy. This led to a strong position from which to draw meaningful processing implications from the mineralogical data. Reproducible flotation testing and reliable plant survey material for characterisation was dealt with by, amongst others, High Confidence Flotation Testing ( Lotter, 1995: Runge, 2010, and Bradshaw, 1997); and Statistical Benchmark Surveying (Lotter, 2005), with earlier prototypes which were steadily improved (Lotter, 1994; Restarick, 1976). The sterling work of Napier-Munn in engaging sound statistical methods with mineral processing led to the successful design and use of methods that could identify and quantify small recovery gains in plant scale trials. This history and present capability are reviewed, including leverage into asset management.

Jan 1, 2018

By M. Barati, K. Ebrahimi-Nasrabadi, P. W. Scott

"The conversion of cryptocrystalline magnesite to caustic magnesia was studied experimentally at temperatures of 400–1,200°C and for calcination times of up to 8 h. A differential thermal analysis– thermal gravimetric analysis showed that decomposition begins at temperatures as low as 340°C and is completed at 600°C. Specific surface area, iodine adsorption number, crystallite size, and loss on ignition were measured to characterize the product quality. It was found that high-quality caustic calcined magnesia can be produced in a narrow temperature (600–650°C) and time range (1–4 h).RÉSUMÉ La conversion de magnésite cryptocristalline en magnésie caustique a été étudiée de manière expérimentale à des températures de 400 à 1200 °C et pour des temps de calcination atteignant 8 heures. Une analyse thermique différentielle – analyse thermique gravimétrique montre que la décomposition commence à des températures aussi basses que 340 °C et qu’elle est complète à 600 °C. La surface spécifique, l’indice d’adsorption de l’iode, la taille des cristaux et la perte au feu ont été mesurés afin de caractériser la qualité du produit. Il a été trouvé qu’une magnésie caustique calcinée de grande qualité peut être produite dans un petit écart de température (600 à 650 °C) et dans une période de temps variant entre 1 et 4 heures."

Jan 1, 2015

By R. K. Borden

Rio Tinto is committed to proactive mineral waste and acid rock drainage management. Corporate requirements are closely aligned with the GARD Guide principles of early geochemical characterization and prediction followed by selection and implementation of management strategies to prevent or minimize ARD. Each operation is required to design and implement an ARD and Mineral Waste Management Plan. Successful implementation of the plan requires commitment at all levels of the company, from senior management, to geologists, mine planners, environmental staff and equipment operators. Examples of the successful integration of ARD management strategies into mine operations are cited from several mines.

Jan 1, 2011

By Nordau R. Goodman

"IntroductionTHE HISTORY of Nova Scotia's gypsum industry goes back about two hundred years. The extensive deposits found in the Windsor formation, which is Lower Carboniferous, were the first discovered in North America and were known to the earliest .settlers. There has been a steady increase in production from these beds, except for minor setbacks in years of wars and depressions, but at the same time there has been a decrease in the number of operating quarries. This decrease reflects the change from the days of horse-and-cart recovery to the modern, large-scale, highly mechanized operations. In the beginning, almost any outcrop could •supply the tonnage requirements and the most •convenient were selected, but the millions of tons needed to meet present-day needs are not easily found.Despite the size and importance of the Nova Scotian deposits there has been little detailed geological work. Sir Charles Lyell, in 1843 ( 10), established that the beds are Lower Carboniferous and this was confirmed by Sir William Dawson (3) a .few years later. Both Lyell and Dawson agreed the calcium sulphate beds were an original part of a bedded series .but did not consider they resulted from a concentration of sea water. Lyell reached the conclusion that the gypsum was related to volcanic action in the form of heated vapours or hot springs. Dawson believed it was formed by the action •of sulphuric acid on calcium carbonate. The acid, derived from the oxidation •of iron pyrites which was abundant in the older formations, was carried by rivers into basins which were rich in shells."

Jan 1, 1954

By Ian Ewart, Trevor Bergfeldt, Gourab Satapathy, Ajay Patel

"Conventional electrowinning (EW) of nickel from sulfate electrolytes is complicated by several factors including the requirement for a diaphragm cell to separate the anolyte and catholyte and the need to minimize nickel mist emissions. Developed and commercialized by emewCorporation, this novel process electrowins high purity nickel cathode (99.5%) from copper refinery bleed streams using the proprietary emew vortex EW technology. The emew nickel process incorporates high flow rate in an enclosed cylindrical EW cell operating at high current densities that overcomes the challenges of conventional nickel EW and completely eliminates the risk of nickel mist emissions. The tubular cathodes are easily harvested and mitigate the effect of plating stresses inherent in nickel EW. The present paper describes the emew nickel process and its most recent application to copper refinery bleed streams at full-scale.INTRODUCTION To meet the stringent demand of customers, nickel producers are giving prime importance to production of high purity nickel cathodes. The major challenge for refineries is to improve cathode quality and appearance despite fluctuating electrolyte impurity levels. The basis of achieving good quality cathode includes the control of electrolyte impurities and consistency of specific process conditions. The commercial operation of emew nickel technology has been successfully implemented and has demonstrated the ability to produce high quality nickel cathode from refinery bleeds. This paper emphasizes the importance of upstream impurity removal to achieve the required nickel emew feed composition by evaluating the benefits of using selective precipitation as a purification scheme with the aim of improving the overall nickel recovery while ensuring suitable nickel concentration in the advanced electrolyte is achieved. Nickel electrowinning is similar to other electrowinning processes that employ insoluble metal anodes & cathodes. It requires the passage of direct current between two electrodes that are immersed in a conductive, aqueous solution of nickel salts. For the recovery of nickel from solution, the most common methods are electrowinning and hydrogen reduction. Electrowinning usually occurs from sulfate, chloride or mixed sulfate/chloride electrolytes. In sulfate electrolytes, nickel electrowinning cells are normally designed to achieve specific criteria as outlined below (Robinson & Tuppa, 2002):"

Jan 1, 2017

By S. Kelebek, B. Nanthakumar

ABSTRACT The sensitivity of sulphide minerals towards oxidation depends on the mineralogical makeup and nature of sulphide ores. This paper focuses on chalcopyrite behaviour in a nickel-copper sulphide- ore matrix that was aged in the mine-site stockpiles. Results of collectorless, collector-induced flotation and recovery by size are presented following a discussion of XPS analysis that was used to gain insight into oxidative alteration of chalcopyrite’s surface chemistry. Chalcopyrite maintains its high flotation activity despite exposure to weeks of oxidative conditions. It is concluded that chalcopyrite is quite tolerant to stockpile oxidation due to various factors related to alteration of its surface chemistry.

Jan 1, 2012

By Staff

The Tetreault mine, operated by the British Metal Corporation (Canada), Limited, holds a unique position in Canadian mining, being the only steady producer of zinc in Canada east of the Rocky mountains. Its importance in Canadian zinc production may be gauged with some accuracy, since, in 1927, it was responsible for over 13 per cent of the zinc output of the Dominion. In addition, it also made valuable contributions to the production of lead, silver, and gold. Location: Situated in the foothills of the Laurentian mountains, 600 feet above sea level, 20 miles from the St. Lawrence river, and 52 miles due west from the city of Quebec, the property is in the township of Montauban, county Portneuf, Province of Quebec, as shown in Figure I. The municipality of Montauban, immediately adjoining the mine, has a permanent population of 700 people and is six miles by road from Notre Dame station on the main line of the C.N. Rys. between Montreal and Chicoutimi-Notre Dame being n6 miles by rail from Montreal. Connection by 19 miles of dirt-and-gravel road with the Provincial highways' system of Quebec Province, the city of Quebec, which is distant 78 miles, can be reached by automobile in less than three hours, while the distance to Montreal by road is 16o miles .

Jan 1, 1928

By H. J. White

The effect of alloying elements on the mechanical properties and weldability of wrought gamma prime strengthened nickel- base superalloys is well known. An understanding of the basic guidelines concerning alloying additions has led to the invention and development of HAYNES® 282® alloy for applications in aircraft and land base gas turbines and other high-performance high-temperature environments. The alloy combines exceptional high temperature properties with good weldability and fabricability. At high temperatures (~ 900 °C), the alloy is stronger in creep strength than Waspaloy alloy (UNS N07001) and it approaches the creep strength of R-41 alloy (UNS N07041). Because the alloy has better thermal stability, fabricability, and weldability than Waspaloy and R-41 alloys, it is currently being considered as a candidate universal consumable for welding/ repair welding of gamma prime strengthened nickel based superalloys and it is also being considered as a suitable replacement for applications where R- 41, Waspaloy, and 263 (UNS N07263) alloys are currently being used. The alloy was designed to have improved resistance to strain age cracking, a problem common to gamma prime strengthened nickel based superalloys. In this paper, we present (1) results from hot ductility testing of annealed and annealed/aged material; (2) results from Time Resolved X-ray Diffraction (TRXRD) studies during a welding thermal cycle of annealed and annealed/aged material, and (3) gas metal arc (GMA) and gas tungsten arc (GTA) welding of annealed and annealed/aged material.

Jan 1, 2010

Traditionally within the mining industry, single models for both grade and geology of orebodies are created upon which all mine development decisions are based. These models provide a single interpretation of the extent and continuity of the mineralization envelope based on solids and sections interpreted from relatively wide spaced drilling i.e. the models infer behaviour of grade and geology at smaller/local scales based on data available at wider scales. The variable behaviour of grade and geology cannot be derived from single kriged resource models. In recognition of this, Newmont Mining Corporation typically uses Sequential Gaussian Simulation (SGS) to quantify grade variability and to determine its effect on some of these mine development decisions. In most of these studies the mineralized envelope remains fixed and grade simulations are generated within a fixed volume. To account for uncertainty in the geology/ mineralization envelope Newmont Mining Corporation has been experimenting with Multiple Point Statistics (MPS). Multiple-Point Statistics is an emerging technique, which can be used to generate multiple, geologically realistic, realizations of data that displays complex non-linear features. MPS uses a conceptual model of the geology, called a Training Image (TI), to infer these high-order spatial relationships. The multiple realizations allow for an assessment of the geologic uncertainty, which can be further combined with grade simulations to generate a more complete picture of the true uncertainty of a mineral deposit.

Jan 1, 2011

By M. Seyed Ahmadi

This study investigates the role of nitrogen gas injection in the dissolution rate of Si into liquid Al. A unique revolving liquid metal tank was used, with a capacity of 50 kg of liquid Al. Experiments without gas injection have shown that the dissolution of Si increases as the bath superheat and the tangential velocity of the liquid Al increase. When injecting nitrogen gas at flow rates between 0-5 lit/min in the vicinity of the solid Si, results so far clearly show greater dissolution. In addition, results on the role of the gas flow rate relative to the position of the nozzle are presented and analyzed.

Jan 1, 2011

By Rodney Trevor Jones, Arthur Robert Barnes

Anglovaal Minerals acquired the Nkana slag dump from Zambia Consolidated Copper mines (ZCCM) in 1998 and embarked on an ambitious project to pioneer the recovery of cobalt from slag using DC smelting technology. Anglovaal Research Laboratories performed initial pioneering smelting tests in a 250 kW DC furnace over a 3-year period before engaging Mintek for three piloting campaigns at the 1.5 MW level. Mintek had previously developed a reductive smelting process, patented in 1995, using a DC arc furnace for the recovery of cobalt from slags. The results of the pilot-plant test campaigns were used as the basis for engineering the commercial 40 MW operation installed at Chambishi Metals plc in Zambia in 2001. This paper traces the development of understanding of the metallurgical fundamentals ultimately used to predict furnace performance, reviews some of the extreme technical challenges faced, how solutions were identified and highlights some of the critical issues identified during piloting and how these impacted both positively and negatively on the final commercial operation.

Jan 1, 2011

By Alan A. Barton

Introduction The Little Long Lac mine is situated in the Thunder Bay mining district, township of Errington, Ontario. The mine is located on the south side of the most westerly bay of Little Long Lac. The property consists of 36 claims, which comprise some 1,400 acres. This group of claims was staked in August, 1932, by Tony Oklend and Tom Johnson, and, after surface sampling, was optioned by the present controlling interests, who diamond-drilled it during the winter of 1932-33. In early spring, a small steam-driven plant was installed, and shaft sinking commenced on June 1st, 1933. During the summer, all supplies are transported to the mine from Hardrock station, at mileage 18 on the Canadian National Railway line from Longlac to Port Arthur. At Hardrock, which is seven miles from the mine, the railway skirts a bay of Little Long Lac, and supplies are loaded directly from railway cars to scows. Two scows are used, of 30-and 45-ton capacity, respectively. A 36-ft. pointer, powered by a 35 h.p. engine, is used as a tug. A good winter-road has been cut out from Geraldton to the mine, for winter transportation. Geraldton is about two miles north of the mine, and is also located on the Canadian National railway. A hard-surface road is now being constructed for summer as well as winter use. Geology The Little Long Lac gold area covers the northern limits of a large synclinal structure, the contact of the Keewatin flows and sediments, striking about twenty degrees north of west, with the dip of the sediments varying from eighty degrees north to seventy degrees south, the average being around eighty degrees south. The vein worked by Little Long Lac Gold Mines occurs in massive sedimentary rock of about the composition of arkosic or quartzitic greywacke, and consists of a shear-zone up to fifteen feet in width, striking N.75°E. and dipping steeply to the south, which has been filled by numerous narrow, parallel quartz veins and. veinlets. These are well mineralized. with arsenopyrite, pyrite, and some chalcopyrite and stibnite, and carry considerable quantities of visible gold. They show more than one age of quartz deposition, the quartz being fractured and re-cemented. The arkosic rocks separating the veins and veinlets are also slightly mineralized with pyrite. Work to date has indicated the probability that the vein-shear is controlled by local drag-folding.

Jan 1, 1935

By M. Drozd, M. Somppi, Z. F. Yamak

"Activated carbon is used to recover gold in solution from various gold circuit designs including carbon-in-pulp (CIP), carbon-in-column (CIC), and carbon-in-leach (CIL) processes; however, the characteristics and durability of the activated carbon can vary. Handling this medium poses challenges when fine carbon losses occur in the CIP, CIC, and CIL circuit discharge. Additionally, adsorbed gold on carbon fines can be lost to the discharge. The studies in this paper aim to standardize laboratory methods for testing activated carbon qualities specific to the gold industry. The investigation focused on size distribution, platelet content, wet attrition resistance, gold kinetics, and gold loading. The results demonstrate that a 96 h attrition test and a gold loading test form a basis for ranking carbon samples based on expected economic performance of the plant. ¦ KEYWORDS Activated carbon, Carbon attrition, Carbon ball-pan hardness, Carbon evaluation, Carbon fines loss, Carbon turnover RÉSUMÉ Le charbon actif sert à récupérer l’or en solution dans diverses conceptions de circuits de broyage d’or, notamment les procédés de charbon en pulpe (CIP, de l’anglais carbon-in-pulp), de charbon en colonnes (CIC, de l’anglais carbon-in-column) et de lixiviation au carbone, ou charbon au lixiviat (CIL, de l’anglais carbon-in-leach). Toutefois, les caractéristiques et la durabilité du charbon actif varient. La manipulation de ce milieu pose des problèmes dès lors que se produisent des pertes de carbone à grain fin dans la décharge des circuits CIP, CIC et CIL. Par ailleurs, l’or adsorbé sur les fines de charbon peut se perdre durant la décharge. Les études réalisées dans le cadre de cet article visent à normaliser les méthodes de laboratoire pour tester les qualités du charbon actif spécifiques au secteur de l’exploitation aurifère. L’étude portait sur la composition granulométrique, la teneur des plaquettes, la résistance au frottement humide, la cinétique de l’or et l’adsorption de l’or, à savoir la capacité du charbon actif à adsorber l’or sur une période spécifique. Les résultats ont montré qu’un test de frottement de 96 heures et un test d’adsorption de l’or constituaient le fondement d’un classement des échantillons de carbone du point de vue économique en vue de trouver l’échantillon générant le meilleur rendement des usines. ¦ MOTS CLÉS charbon actif, dureté de la batée des billes de carbone, évaluation du carbone, perte de fines de charbon, renouvellement du carbone, résistance au carbone INTRODUCTION The use of activated carbon for gold extraction is among the most common processes in modern gold-milling plants. Although gold losses are inevitable in the milling process, operators often focus on reducing gold loss to tailings. One focus area that is important in gold recovery is optimizing the use of activated carbon and examining potential changes to realize improved economics for carbon-in-pulp (CIP), carbon-in-column (CIC), and carbon-in-leach (CIL) processes. Granular activated carbon (Figure 1) is widely used for gold extraction from slurries containing gold-cyanide complexes. This activated carbon—produced from charred coconut shells—is well suited because of its adsorption kinetics, gold-loading capacity, attrition resistance, and ability to be reactivated. The extraction process using activated carbon technology involves adsorbing gold from an aqueous leachate; the gold is dissolved using a cyanide salt and consequently a dicyanoaurate(I) ion (Au(CN)2–) is formed, as noted in equation 1."

Jan 1, 2019