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By E. Herrera, L. Mariscal

"Ilo Copper Smelter operates since 2007 with an ISASMELTTM furnace as a single smelting unit (1,200,000 tpy) associated with two Rotary Holding Furnaces for separation of matte and slag, and which directly produces a discard slag. Southern Peru continually has been improving the slag chemistry of its ISASMELTTM furnace in order to reduce copper losses, given its big economic impact due to large slag mass generation. The present paper describes the influence of the CaO, Al2O3 and magnetite content in the slag of the ISASMELTTM furnace correlated with the SiO2/Fe ratio and its liquidus slag. Also it defines the best slag chemistry and operating practice in order to reduce the copper losses without compromise the bricks life of the furnace.INTRODUCTIONIlo Copper Smelter of Southern Peru (Grupo Mexico) is located on the southern coast of Peru, and treats mainly copper concentrates produced in its own mines (Toquepala and Cuajone).The modernized smelter was commissioned in 2007 and operates with an ISASMELT™ furnace as a single smelting unit (1,200,000 tpy), which is associated with two Rotary Holding Furnaces (RHF) for separation of matte and slag. This slag is directly sent to the dump. Figure 1 shows the smelter flow diagram.The ISASMELT™ process is a bath-smelting process using a single lance. The lance tip is immersed into a molten slag bath contained within the stationary, vertical, refractory-lined ISASMELT™ furnace. The injection of oxygen-enriched air, through the lance into the slag results in a highly turbulent molten bath. Feed material falling into the turbulent bath from above reacts rapidly, resulting in extremely high productivity for a relatively small bath volume."

Jan 1, 2012

By John S. Stevenson

Zeballos mining camp is on the west coast of Vancouver island; 195 nautical miles northwest from Victoria.; The spectacularly rich gold-bearing veins that made Zeballos an important; gold camp were found early in 1934. Small pockets of very coarse; gold had been found earlier under large boulders at the mouth of Spud; creek; and in the autumn of 1933 rich gold-quartz float was found near the; mouth of the creek. The rocky beds of the steep creeks entering Spud creek; were searched for its source and as a result the veins on the White Star property; were found. The Goldfield vein on the Spud Valley property was discovered; in 1935; and the No. 1 vein on the Privateer in 1936. In the general; prospecting activity that quickly followed; other veins were found; not; only in Spud creek but in other creeks draining into Zeballos river.

Jan 1, 1954

By T. Mulpeter, G. Deschênes

Sadiola Gold Mine is an open pit operation located in Mali and owned by Anglogold Ashanti Ltd, Iamgold Corporation and the State of Mali. A conventional cyanidation process (cyanidation/CIP) treats 15,000 tpd (of a mixture of oxide and sulphide ores) at an average grade of 3 g/t Au. In 2002, the increasing tonnage of sulphides caused an increase in production costs and a decrease in gold extraction (from 95% to 70-76%). Because of the short retention time of the leach circuit (18 hours) and the refractory nature of the sulphides, gold leaching kinetics are critical. A laboratory investigation was initiated to evaluate actual plant practice and identify a means of improving the gold leaching rate. The study was conducted on a "soft" sulphide gold sample containing 4.96 g/t Au, 0.4 g/t Ag, 2.5% pyrite, 1.2% arsenopyrite, and 0.2% pyrrhotite with a P80 of 74microns. Pre-leaching significantly influenced the gold leaching rate. A short pre-leach (2 hours) performed at pH 8, a DO of 8 ppm, and with 300 g/t lead nitrate added at the start or the end, produced the preferred conditions. Pre-leaching for more than 2 hours was detrimental to gold extraction. The cyanide concentration had to be maintained at 450 ppm NaCN to reach a maximum gold extraction within the retention time of the circuit. A maximum extraction of 81.3% Au was obtained in 20 hours (leach residue at 0.97 g/t Au). A high level of dissolved oxygen in the pre-leach was not of any benefit. Extension of gold leaching beyond 20 hours indicated that all leachable gold had been extracted by that time. Plant modifications were made to allow leaching of oxides and sulphides in separate circuits. Treatment of oxide ores is now performed at a higher rate. Sulphides are processed at a lower throughput, with 300 g/t lead nitrate, to allow a retention time of 22 hours. Combined throughput remains the same, and total gold recovery has increased from 76% to 80% for an additional gold production of 16,000 ounces per year.

Jan 1, 2005

By D. Campbell Mackenzie

THIS paper is submitted primarily to put on record the results of a number of experiments carried out at the Wingdam mine of Consolidated Gold Alluvials of B.C., Ltd., with the object of establishing a reliable method of concentration of 'wash' and a maximum recovery of gold from the concentrate. It will be generally admitted that, during the last two decades, a tremendous amount of research work has been carried out, both by private companies and Government departments, with a view to improving the technique of the recovery of gold .from quartz veins or lodes. So thorough have been these investigations that milling practice at a modern quartz gold mine is almost an exact science, carried out with meticulous accuracy. In placer mining, on the other hand, very little departure from old traditional methods can be noted, with the exception perhaps of the more modern gold dredges. This may be due to the fact that the concentration of placer gravels, up to a certain point, is comparatively easy. Only a simple equipment of sluice box and riffies seems necessary where the gold is coarse and the gravel free from clay. In the early days of placer mining, when claims were rich and fairly 5hallow, nobody worried very much about fine gold; and, if clay was present, an enlarged dump box was constructed in which the gravel was subjected to a rather desultory puddling. That large quantities of gold are lost in normal placer practice is generally admitted. Some 26 years ago, I had inspectorial charge of many bucket dredges on the Ovens river, in Australia. Occasionally it was necessary for a dredge to work through its own tailing to reach a new section, and almost without exception enough gold was recovered from these tailings to defray the total cost of moving the dredge. Since those days, the technique of gold recovery in dredging has been considerably improved and it is still receiving close attention. Outside of dredge mining, most placer operations, deep or otherwise, are as they were-notorious gold losers, paying little attention to the recovery of fine gold and taking an absurd amount of time over each clean-up. In the Cariboo district of British Columbia, the alluvial gold is usual y associated with varying quantities of black sand (magnetic) and grey sand (non-magnetic); and it can be taken as axiomatic that, if you save all the black sand and grey sand, you save practically all the gold. It is on this hypothesis that we have carried out our research work and brought our recovery system up to its present highly satisfactory standard.

Jan 1, 1937

By W. T. Irvine

"The Britannia ore deposits are approximately 20 miles north of Vancouver; and occur in a prominent ridge facing Howe sound. A large ironstained bluff first attracted the serious attention of early prospectors. This; upon investigation; proved to be the outcrop of a large copper orebody. The highest outcrops were 4; 300 feet above sea-level.The original discovery was made in 1888, but no real development took place until 1902. The first mining was done in what came to be known as the Jane orebody, and some production was obtained from this in 1905. Underground exploration led to the discovery of several other orebodies. The first main adit, the 1,050-foot level, was driven to tap the ore at an elevation of 3,300 feet above sea-level. During succeeding years, however, long adits were driven from points lower down on the mountain side. These, with connecting shafts, followed the ore to horizons well below sea-level. The lowest working has now reached to 880 feet below sea-level. The property has been in almost continuous operation since its original exploitation in 1905. Until the end of 1944, 732,414,420 pounds of copper and 261,125 ounces of gold had been produced from the mine."

Jan 1, 1954

By E. Esmaeilzadeh

There arc 8 primary ball mills in the concentrator plant and their task is material crushing. At the time of balls charge to mills, a lot of noise is produced. This noise would affect all grinding areas. The aim of this research was a reduction about 16 dB at source sound power level (SWL was 129.1 dB). With considering two noise control principles, noise producer sources and propagation paths were specified. For removing and reducing of noise producer sources, rubbers with a thickness of 5-20 mm were used on the all inside surfaces of charge box, ball transferring box and exit canal. For increasing transmission loss and damping coefficient of charge box body, rubber with thickness of 1 cm at outside surface of box was used. For reduction of noise propagation a secondary metal cover was designed and made. This cover includes two parts and was set around the charge box. Glass wool (75 kg/m3) with 10 cm thickness was used as acoustical absorbent between free space of two body's layers and from secondary cover side. The of the rest space was left empty. After installing of secondary cover on the ball charge box no.4, SWL showed a reduction about 16 dB. For studying of control system effect on noise reduction at points far from of charge place, measuring results at these points showed the maximum reduction 12.1 dB and the minimum 11.8 dB.

Jan 1, 2007

By A. R. Byers

"Porcupine Peninsular mine is at the extreme southwestern end of North peninsula in Night Hawk lake, Cody township, Ontario. It lies approximately 10 miles east of the gold-producing district of Porcupine.Gold in quartz veins was discovered on Gold -island in Night Hawk lake in 1906, the same year in which the now famous Porcupine gold camp was discovered farther west. Most of the claims now held by the Company were originally staked by Charles Auer in 1907, In 1910 when the level of the lake was exceptionally low, gold was discovered in a quartz vein near the shore and close to the present mine shaft.The mine is developed by a main shaft to a depth of 440 feet, with levels at 80, 180, 300, and 425 feet vertical depth and by a winze to 630 feet. A mill of 200 tons daily capacity was built during 1923, Production commenced on January 4, 1924, and continued without interruption to May 31; 1926, when operations were suspended due to a decrease in the grade of ore. Total production amounted to 27,416 ounces of gold from 99,708 tons of ore, an average grade of 0.275 oz. a ton. Diamond drilling and re-sampling of the mine during 1934 and 1935 indicated approximately 1,480,000 tons, having an average grade of 0.123 oz. gold a ton, above the 625-foot level."

Jan 1, 1954

By J. Shanks

In 1920 the writer presented some notes, embodying his experience with storage-battery locomotives as main under-ground haulage-motors at Brazeau collieries. (1) Since that date these motors have stood up well to the test of maximum output and heavy overloads, having accomplished all that was expected of them. The notes presented in 1920 gave a brief description of the conditions under which these motors were working at Brazeau collieries, also the cost, per ton mile, of operating them. The cost per ton mile has since then been appreciably reduced, by working the locomotives nearly to capacity and under more ideal haulage conditions, on both shifts. It is not the intention of the writer to repeat what was written in 1920, but rather to give members the benefit of his experience in operating different types or designs of locomotives; to draw their attention to the drawbacks of some designs, and to the improvements made in some of the more recent storage-battery locomotives put on the market, as regards efficiency, upkeep, and safety. Because of their flexibility storage-battery locomotives have advantages over any other type of haulage, where grades are suitable to their use. The number in use in the mines in the United States has increased enormously during the past few years, and this method of haulage is, at the present time, attracting the attention of British and Continental mining engineers.

Jan 1, 1924

By H. Tan

The effect of carbonaceous matter on gold extraction was investigated in cyanide systems with pure gold as well as pre-robbing sulfide gold ores. Auger studies demonstrated that the carbonaceous matter preferentially smeared on iron sulfide rather than aluminosilicate surfaces during wet or dry grinding. During mechanically mixed leaching, coating of sulfides and silicates and stripping of carbonaceous matter occurred simultaneously. TEM and XPS studies indicated preferential coating in the form of elemental (graphitic) carbon at the edges and the defect sites of particles. Interestingly, carbonaceous matter extracted from the gold ore was predominantly graphite and not preg-robbing in a solution with a high KCN concentration. However, the carbonaceous coating had a significantly detrimental effect on gold dissolution when gold was pre-ground with the gold ore. Artificial coating on gold surfaces with the natural carbonaceous matter from the ore was also found to substantially retard gold dissolution. With the addition of the natural carbonaceous matter from the gold ore, gold extraction from two non preg-robbing sulfide gold ores was inhibited owing to carbonaceous coating. The presence of carbonaceous matter significantly reduced the current density for gold oxidation and increased the current density for pyrite oxidation. This could explain the fact that carbonaceous coating hindered gold dissolution while enhanced sulfide preg-robbing.

Jan 1, 2005

By O. Alonso-Gonzalez, F. Nava-Alonso, A. Uribe-Salas, R. Pérez-Garibay, C. Jimenez-Velasco

A current problem in gold production is the presence of copper minerals which dissolve during conventional cyanidation practice. The dissolved copper causes several problems in the different stages of the process. This issue is the base for copper elimination/recovery methods such as the Sulphidization, Acidification, Recycling, and Thickening (SART) process, which is currently used in gold production plants around the world. Even though the process is well established, new challenges appear as the composition of the solution varies from ore to ore, in some circumstances affecting the performance of the SART process. This work presents a thermodynamic study and experimental tests performed to understand the role of the initial copper concentration and sulfur addition, on the efficiency of the copper removal. For a constant cyanide concentration, an increase in the initial copper concentration causes a decrease in copper removal; high sulfur/copper molar ratios favor copper removal. We demonstrated that the cuprous sulfide formed from solutions with high ionic strength, presents better sedimentation rates than solutions with less ionic strength. For solutions with low sedimentation rates, the use of some pretreatment is necessary to facilitate the sedimentation such as addition of flocculants, particle recirculation and the used ultrasonic pretreatment.

Jan 1, 2014

By M. Mezbahul-Islam

Thermodynamic modeling of the Mg-Cu-Ni system is carried out as a part of multi component thermodynamic database for Mg alloys. This system is being modeled for the first time using the modified quasichemical model, which considers the presence of short range ordering in the liquid. The thermodynamic descriptions of the binaries Mg-Cu, Cu-Ni and Mg-Ni have been extrapolated to the ternary Mg-Cu-Ni system using Toop geometric model. The constructed database has been used to calculate and predict thermodynamic properties, isothermal sections and liquidus projections of the Mg¬Cu-Ni system, which showed very good consistency with the experimental data.

Jan 1, 2011

By J. W. Hohn

The precipitation of Fe(III) to form ferrihydrite in the presence of arsenic is the United States EPA's Best Demonstrated Available Technology for treating arsenic-containing hydrometallurgical solutions and waste streams. This technology has been widely adopted throughout the world and developments have been well reviewed. The adsorption and long-term stability of ferrihydrite can be improved by co-precipitating Fe(III) and Al(III) together to form an aluminum-modified ferrihydrite. Arsenate adsorption into ferrihydrite and modified ferrihydrite as a function of pH, Fe/As or (Al+Fe)/As mole ratio, and the initial As(V) concentration is presented and compared. The results of long-term aging of both adsorbents at 70°C for over a year are also summarized.

Jan 1, 2006

By D. B. Hyma

"The Raglan Ni/Cu property is located on the Ungava Peninsula in Northern Quebec, Canada, at a latitude of61°42' and a longitude of73°40', approximately 40 km southwest of Douglas Harbor. Geological reserves are estimated at 18 million tonnes, grading 3. 1 % nickel, 0.9% copper and smaller amounts of cobalt and platinum group metals.Extensive project development has defined the concentration process, concentrator sizing, tailings and environmental management required for this project.The grinding circuit selected is a fully autogenous primary grind, with pebble crushing and a pebble mill for secondary grinding to produce a product of 80% -70 microns for flotation.The flotation circuit is a simple circuit utilizing roughing, a regrind of rougher concentrate to 80% -20 microns, two stages of column cleaning with a cleaner scavenger bank on the column tails.Concentrate handling options were thoroughly reviewed because of the pyrophoric nature of the concentrate, remote site location and long distance to downstream processing. The preferred option, currently.is to dry the concentrate at Raglan to less than l % moisture and then pneumatically handle the powder.A detailed analysis of tailings placement options, suggests filtered tailings placement to be the preferable route for the Raglan site.INTRODUCTIONThe Raglan Project, as proposed by Falconbridge Limited, will develop extensive nickel-copper deposits in the Ungava Peninsula, Quebec, Canada. The project schedule and construction conditions in the project area are demanding. The Raglan mineral deposits have been the subject of numerous studies and evaluations over the last thirty years and the Phase I 1991 pre-feasibility document includes exploration information obtained in the 1989 and 1990 drilling seasons. This review concluded that an 800,000 tonnes of ore per year mining and concentrating complex located at Katinniq could produce 20,000 tonnes per year of nickel at competitive costs."

Jan 1, 1993

By H. C. M. Gordon

MR. A. D. BADOUX: I have listened to Mr. Gordon's excellent paper with great interest, as I personally have gone through some of the experi­ences he has so clearly depicted. In particular, there were a good many times when we were greatly exercised in our minds as to whether we were justified or not in closing-off certain sections in the Allan mine. The difficulty in these cases arose from the fact that a peculiar smell could be detected in these sections but at the same ti me there was no positive evidence of spontaneous combustion either from heat being apparent or from the possible indications of fire getting any worse. It was suspected that the small percentage of -carbon monoxide that could be obtained by analysis in the air in these sections, and also the peculiar odour, were emanating from the coal itself, and, in order to verify this, bore-holes were drilled in the coal and the gases released from these bore-holes were analyzed. They were found to contain carbon monoxide. After quite a considerable length of time this contained carbon monoxide gradually diminished and finally could not be detected when analyzing such samples of gas. It was our intention to follow this matter up further, as such an occurrence of carbon monoxide is practically unknown, but the sections in which these occurrences were found had to be abandoned. Mr. Gordon referred t0 a case of spontaneous combustion in the Allan . mine, and I may say that, although the section in which that occurrence took place was travelled and carefully examined every day by the colliery officials, yet nothing unusual was noticed until the fire actually took place. This tire was the cause of a slight explosion.

Jan 1, 1938

By W. H. Fertl, S. J. Pirson

Well logging techniques, as used successfully in oil and gas exploration, can also be used to give a detailed evaluation of drill holes through industrial mineral deposits such as sulphur. This paper describes the logging tools used gives the theory behind the well-log interpretation and discusses the application of the method in sulphur-bearing limestone and m more complex sulphur deposits.

Jan 1, 1970

By S. J. Prout, J. M. Lang, D. Lascelles, K. Sarinas

"There is a growing demand for ore characterization methods to support metallurgical development programs from a true geometallurgical perspective. Today, there are multiple automated mineral analysis systems on the market, many of which are based on conventional mineral liberation data. However, liberation data can be limited when assessing the floatability of a mineral to predict its recovery as it doesn’t consider the surface area available for collector absorption and bubble attachment; whereas mineral exposure measurements can. Using the First-Order Rate equation to predict the recovery versus time of variously exposed particles, a model has been developed to predict the recovery of copper sulphides at a particular grind size. This model provides the opportunity for the prediction of copper recovery and grade from multiple, small-scale samples. These predicted values can be imported into resource modeling software, and guide the domaining of geometallurgical units within the ore body. Data has been analyzed from various global copper porphyry systems and compared with actual flotation testwork.IntroductionAs part of the development of a mining project, resource estimation primarily focuses on the definition of the quantity and grade of the ore in the deposit; as the project evolves from preliminary economic assessment through to feasibility, the geological model is usually further populated with hardness and recovery data.The CIM Definition Standards (2011) identifies measured mineral resource as the part of a mineral resource for which quantity, grade or quality, densities, shape, and physical characteristics are estimated with confidence sufficient to allow the application of “modifying factors” to support detailed mine planning and final evaluation of the economic viability of the deposit as an asset. The modifying factors include, but are not restricted to, mining, processing, metallurgical, infrastructure, economic, marketing, legal, environmental, social and governmental factors.With market fluctuations, many investors in the mining industry have become more and more risk averse which has increased the demand for more reliable data to support these modifying factors. This has led to the widespread use of geometallurgy and statistical analysis to better inform the resource estimation. Geometallurgy is used to characterize ore variability and is especially useful for highly variable or strongly zoned deposits, several close deposits that will be milled together, projects requiring complex or new metallurgical approaches, brownfields or sight-of-mine exploration, expansion projects that exploit new, deeper or adjacent reserves, and projects with significant legacy drill core that are being re-evaluated due to new economic circumstances."

Jan 1, 2018

By Azadeh Riahi

The main goal of this paper is to investigate the effects of permeability anisotropy in Large Open Pit (LOP) mines for problems that exhibit homogeneous anisotropic characteristics. The most important effect of the groundwater flow in open pit mines is on the stability of the pit slopes. This study will investigate the effects of having increased permeability in both horizontal and vertical directions on three aspects of LOP behavior, location of phreatic surface, pore pressure distribution and stability of slopes. The hydromechanical coupling is simulated using a one-way coupling approach. The Shear Strength Reduction method (SSR) is applied to assess the stability of slopes. The studies performed in this paper suggest that anisotropy in permeability leads to a significantly different regime of pore pressure dissipation depending on two aspects, ratio of anisotropy and the relative magnitude of permeability to simulated time. As a result, variation in safety factors and the location and depth of the failure surface must be expected.

Jun 1, 2012

By A. Aubin, H. Yang, G. Zaluski

The Athabasca Basin of northern Saskatchewan and Alberta is an exceptionally rich metallogenic region, hosting more than 2.8 B lb U3O8, of which over 927 M lb U3O8 have been mined out since extraction first started in the late 1970’s. A detailed compilation of several empirical features of 85 deposits located within the basin was conducted in order to understand the distribution and variability of the geological characteristics of the mineralization and its associated alteration. A new empirical classification was devised based on four parameters: 1) geometry of the mineralization (dimensions and relation to the unconformity surface), 2) size, grade and metallurgical complexity of the mineralization, 3) lithostructural setting, and 4) extent and nature of associated alteration haloes. This compilation defines the footprint characteristics of the Athabasca Basin deposits, which guides decision-making processes from early exploration and discovery to resource expansion and extraction.

Jan 1, 2020

By M. Romana

"RMR geomechanics classification is being used all over the World as a useful tool for tunnel predesign and construction. Bieniawski (1989) provided guidelines for tunnel excavation and support, according RMR numerical values; guidelines which are now included in almost all tunnelling books, regulations, and Internet portals. But in the last 25 years tunnelling techniques have changed and some of the guidelines have become obsolete.. The conditions of tunnels for the 1989 guidelines application were: horseshoe shape; 10 m width; vertical stress < 25MPa; construction by drilling and blasting. Actually a substantial number of tunnels are mechanically excavated. The tunnel themselves are now bigger: a span of 14 m. is very common for transportation tunnels. The guidelines included the following concepts: excavation method, rock bolts (20 mm diameter, fully grouted), shotcrete, steel sets. There is an increasing gap between the 1989 guidelines and the practice: in many tunnels different to-the-case excavation and support requirements are established. Bieniawski himself has published a paper (Lowson & Bieniawski, 2013) with different guidelines based in Lowson’s practice, with no explanations and/or justification.In this paper a new set of RMR tunnelling guidelines is proposed taking account of the actual industry conditions, and increased safety regulations. The 5 classes’ limit RMR:values (80,60,40,20) are no more useful actually: Values of RMR (70, 50, 30) are used in practice to define quite different tunnelling techniques. Consequently a 10 subclasses system is proposed. Each subclass covers a span of 10 RMR points. As the number of mechanically excavated tunnels has increased a new correction factor is necessary, according the excavation method.The proposed 2014 RMR guidelines are for tunnels 10 to 14 meters wide, the world practice for new roads/railways tunnels. Many tunnels for water/ services are smaller with smaller support needs. Wider than 16 m caverns are out of the RMR system.It is not possible, nor desirable, to propose only a value for support in each subclass. The new guidelines propose an interval of values for certain types of support. More pessimistic values must be chosen for wider tunnels, tunnels with lower RMR values in each class and cases when a higher safety factor is asked for. More optimist ones are chosen for narrower tunnels, and higher RMR values. Some alternatives are almost complementary, others are contradictory. Sometimes several different techniques are proposed Guidelines are not automatic options. Good engineering judgment must be used when choosing between the different alternatives. Guidelines are not mandatory suggestions."

Jan 1, 2015

By A. Allaire, J. Torrealba-Vargas, R. Welyhorsky

Early testwork was carried out to select the plant process design criteria and flowsheet selection. Additional testwork was carried out during the feasibility study to support the optimization of the plant design criteria. The test results showed that the recovery of gold was not very sensitive to grind size in the range of 75 to 105 microns. An additional result was that the presence of lead nitrate did not improve the kinetics of gold leaching. This conclusion was supported by the low content of sulphides in the ore. It was also found that the presence of lead nitrate increased copper dissolution, producing the potential for an increase of copper reporting to electrowinning, which is detrimental to the overall gold recovery process. The use of oxygen in leaching was investigated to increase leach kinetics. The results of leaching tests to compare using oxygen instead of air indicated that, due to the improved leach time, it was possible to reduce the number of leaching tanks from twenty four (24) to twenty (20).

Jan 1, 2011