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By Jochen Petersen, Jean-Paul Franzidis, Allan Nesbitt

This study presents a method for the determination of intra-particle diffusivities in ion-exchange resins for the purposes of evaluating the state of resin degradation during service. The method uses a zero length column (ZLC) in a closed circuit with variable speed pump and reservoir. The intra-particle diffusion is determined from absorption data by using the Nernst-Plank approximation along with the ‘mass transfer factor’ - which is a product of the mass transfer coefficient (kf )and the concentration of the adsorbing ion in the liquid at the surface of the resin - in a computer algorithm fitting simulated curves to experimental data.. Through this approach the changed intra-particle diffusivity, of a gel-type acid resin, over a 1000 loading and elution cycles, is shown.

Jan 1, 2014

By M. Yao, D. Thibodeau

"Selective mining, such as post pillar cut and fill, is used in large, flat, irregularly shaped ore bodies where ground stability is to be maintained. This selective mining is used to open the stope to the full lateral extent of the ore body in order to minimize the dilution and maximise the recovery. For increased mining depth, design of the post pillar becomes more challenging since those pillars will eventually fail as mining progresses upwards. The post pillar should be designed such that failure does not occur at the early mining stage, such as at the first cut. After mining progresses upwards, the post pillars are expected to fail but be confined by backfill. In order to maximise ore recovery, both drift width and post pillar size must be designed adequately with a consideration of all geomechanic parameters. This paper will describe the process used to design post-pillar cut and fill for one of the ore bodies in Vale’s Copper Cliff Mine using a combination of both empirical deterministic and numerical modelling techniques. By utilizing both empirical deterministic and numerical modelling techniques drift width and post pillar size can be effectively designed. Current post pillar cut and fill design in the existing Vale operations are used to validate the design for Copper Cliff Mine. INTRODUCTIONCopper Cliff Mine is located within the Copper Cliff Offset in the limits of City of Greater Sudbury, Ontario, Canada, as shown in Figure 1. The Copper Cliff Offset extends about eight kilometres south from the Sudbury Igneous Complex into the footwall rocks. Until 2008, the current Copper Cliff Mine was operated as two separate mines i.e. North Mine and South Mine. However, as part of restructuring of Vale Ontario Operations, the North and South Mines were merged in 2009 to form the “Copper Cliff Mine”."

Jan 1, 2015

By Peter A. Hacquebard

"The early history of the Geological Survey of Canada is closely connected with coal geology investigations in the Atlantic Provinces. In 1843, Sir William Logan, the first director of the Geological Survey, measured the 4441m thick shore section at Joggins in Nova Scotia. Detailed mapping of the coalfields were subsequently carried out by H. Fletcher during the latter part of the nineteenth and first part of the present century. During the 1920-1940 period, the stratigraphy of the carboniferous WIZS' established by WA. Bell, who later also became a diretor of the Survey. Bell's work WIZS' followed by coal geology investigations of A.A. Hayes, W.S. Dyer, EA. Goranson, G. W.H. Norman, J.E. Muller, T.B. Haites and P.A. Hacquebord.The activities and accomplishments of the Survey geologists during the past 150 years are presented in this paper.General Outline of Survey Activities in Coal Geology During the Past 150 YearsIn 1842, when the Geological Survey of Canada (GSC) was established, the industrialization of the major countries of Western Europe and North America was actively persued. The energy required for this industrialization was obtained from the only fossil fuel then available, namely coal. The measure of a country's major mineral wealth at that time was the availability of mineable resources of coal. Eastern Canada, where mining had been carried out since 1720, was known to be well endowed with valuable coal deposits. In the major fields of Nova Scotia (Fig. I) several large-scale operations had been started during the middle and latter part of the nineteenth century.The significance of coal, therefore, was well understood, and exploration surveys specifically oriented toward coal were carried out by the Geological Survey from its earliest beginning. The first report of a detailed geological description of the coal measures of eastern Canada was prepared in 1843 by Sir William Logan (1845), the founder and first director of the Geological Survey of Canada. This early work was continued and complemented in 1896 by H. fletcher (1906), who during the latter part of the nineteenth century and first part of the present century systematically mapped the coal-bearing regions of Nova Scotia, which he considered all to be of approximately the same age."

Jan 1, 1992

By Rolf Andreas Lauten, Adam Pratomo, Dani Ramdani, Helminton Sitanggang

A universal challenge for the mineral processing industry is the diminishment of high grade ores. Instead, low grade ores, sometimes also containing problematic gangue minerals is the reality. With lower head grades the industry has to put more effort into processing to maintain the output and achieve suitable recoveries. In an effort to reduce the impact of declining head grade, a biopolymer was evaluated as an additive in the gold leaching operation at Antam Pongkor in Indonesia. Laboratory testing revealed that biopolymer usage lead to an increased gold recovery without apparent negative impact on the other parts of the process. Further plant trials revealed both a recovery increase around 1.3% and higher throughput (9%) in the presence of the biopolymer. Some scenarios that can explain these findings will be discussed.

Jan 1, 2014

By Naizhong Xu

During the past 30 years, fully mechanized caving mining has played a positive role in the improvement of the efficiency of coal production, but which has also had a great influence on the mining environment, especially to environment damage of shallow mining areas in the central and western regions of China. The surface subsidence parameters are the basis of the surface environment evaluation and governance. During 1980~1990s of the last century in China, fully mechanized mining subsidence laws were researched more fully, however, since coal caving technology is affected by many factors, and researches on its mining subsidence laws (parameters) were found to be grossly inadequate. Through actually observed in recent years, it is considered that coal caving mining subsidence laws (parameters) can use fully mechanized mining law (parameters) for reference. Based on fully mechanized mining laws (parameters), this paper reveals the similarities and differences of the surface subsidence laws between fully mechanized caving mining and fully mechanized coal mining, which can guide the work of coal mining under buildings, water bodies and railways in new mine area and mine collapse governance.

Aug 1, 2013

By C. Carlson, W. Muir

"The oxygen demand of the complex lead-zinc-iron feed at the Cyuro Anvil concentrator was determined denendent on the cyanide ion con-contration of the pulp. By redistribution of the cyanide [ ] the grinding circuit in direct proportion to the amount of surface area created, a more activated flotation feed in obtained.Monitoring the oxygen demand of the flotation feed and grinding mill discharge has proved useful in diagnosing metallurgical problems day to day operation."

Jan 1, 1976

By Dennis Hoffmann

"Abstract - Banded iron formation rocks associated with massive sulfide lenses in the Broken Hill Pb-Zn-Cu-Ag deposit in the Namaqualand Metamorphic Complex, South Africa , were investigated with respect to the geochemistry of manganiferous silicate-rich bands. Two common varieties of these are: amphibole- and garnet-rich iron formation bands. The results reveal that the former are enriched in Fe, Mg, Cu, Co and S. The garnet-rich bands are enriched in Mn, Ca, P, Pb and Ba with significant detrital contamination of Ti, Al, Zr, Cr, Y, V, Ni and Nd.The silicate-rich bands have compositions, in terms of, Si/Al, Si/Fe, Fe/Mn, La/Ce and Co/Zn, comparable to submarine chemical sediments which precipitated from hydrothermal fluids. The garnet­ and amphibole-rich bands are interpreted as ""evolved"" and ""immature"" hydrothermal sediments, respectively. The latter resulted from rapid precipitation after exhalation, whereas the former had a longer residence within sea water. The silicate-rich bands both exhibit increasing Mn/(Mn+ Fe) fractions, which are consistent with a variation expected from proximal to distal depositional settings. The prevalence of garnet-rich bands over amphibole-rich bands is interpreted as the result of injection of hydrothermal fluids from a single vent situated along the northwest margin of the Broken Hill deposit."

Jan 1, 1994

By Chris M. Healey

"Perhaps the single most significant variable in the evaluation of a mining project is the reserve estimate. Many parameters are considered when estimating reserves, among them geology. This paper examines the link between the quality of a reserve estimate and a good understanding of the geological controls for the deposit. A clear understanding of the geometry is essential to the accurate definition of the shape and size of the deposit. This includes the definition of any structural controls as well as the proper interpretation of the stratigraphy. Further when the distribution of grades is erratic and there is consequently a high nugget effect, there are significant problems in estimating the true grade of the deposit.Two Saskatchewan examples are presented, one with good knowledge of the controls and therefore good estimates of reserves, and the other with a poor understanding of the geology and resultant problems in deriving good estimates. In both cases the reserve estimates at various stages in the project development are compared to actual results from underground work. The first example is the Star Lake Mine where just about all the estimates were within 10070 of the actual on both tonnage and grade. The Laurel Lake deposit is discussed to show how problems in interpreting the geological data make reserve estimation very difficult. Laurel Lake has the additional problem of erratic grade distribution."

Jan 1, 1992

By J. H. Sokolowski, R. I. MacKay

The level of Si and Cu in the 3xx series of alloys affects the volume fraction of the a-Al dendritic phase and the Al-Si eutectic phase. The volume fraction of these phases in turn affects the feeding conditions during solidification and ultimately the Area Fraction Porosity and Mean Pore Diameter measured in the as-cast structure. This work sets out to establish the relationship between the volume fraction of the a-Al dendritic phase and the Al-Si eutectic phase and the resulting porosity that forms on the Monotonic and High Cycle Fatigue properties. The alloys in question are the Al-9%Si-l %Cu and a Al-7%Si-4%Cu alloys which were cast into V8 performance engine block castings and then heat treated to achieve desired mechanical properties. The engine block castings provided the mechanical and metallographic test samples analyzed for this work.

Jan 1, 2006

By L. Becze, B. Pierre, S. Di Carlo, G. P. Demopoulos

From January to June 2007, the autoclave production at the Kidd Metallurgical Site was severely affected as a result of plugged discharge lines and extensive precipitation/crystallization of sulphates that caused massive scaling in different autoclave compartments. Work was performed at McGill University to understand the root causes. The crystallization of zinc and ferrous sulphate salts was investigated in terms of solubility measurements. Scale samples were characterized using chemical and mineralogical-spectroscopic analysis. In this paper, following a description of the Kidd zinc pressure leach operation, highlights from this investigation are presented and solutions used to overcome the problem are outlined.

Jan 1, 2008

By D. L. Marchioni

"The detection and quantification of the degree of weathering is an important aspect of coal exploration and mining. Tests for weathering which are suitable for the exploration camp should be fast, simple, and require minimal equipment and operator expertise. In this study, two tests which fulfill these requirements were evaluated using samples of Western Canadian coals. These tests, one based on the pH of a coal slurry and the other on the flotation of coal in a water/diesel oil mixture, do not appear to give consistent results and are not recommended as ideal weathering parameters.IntroductionThe weathering of coal results in a deterioration of those properties which render it suitable for use in industrial processes. Consequently, the detection and quantification of the degree of weathering is an important aspect of exploration and mining. Frequently, decisions related to the depth of the weathered zone must be made at the exploration camp and, therefore, tests for weathering which are fast, and require relatively inexpensive and portable equipment and minimal operator experience, would be very useful. The aim of the study reported here was to evaluate two tests used by U. S. Steel Corp. to detect coal weathering and which satisfy the requirements for use in an exploration camp. The study is a continuation of a more extensive examination of the detection of coal weathering by various methods, reported elsewhere (Marchioni, in press)."

Jan 1, 1981

By Louise Corriveau

Exploration strategies have traditionally considered felsic gneiss complexes of the Canadian Shield sterile. This paradigm is challenged with the discovery of extensive granulite-facies Cu-Au, Fe oxides-bearing hydrothermal systems in the 1.4 Ga Bondy and 1.5 Ga La Romaine volcano-plutonic complexes of the Grenville Province. Early identification of magnetite-rich units in association with meta-exhalite and pelite-like units was key to targeting the search for mineralization, protolith information and indicators of pre-metamorphic hydrothermal activity during regional surveys of these frontier terrains. Textural evidences for a volcano-plutonic setting were found. There remained, however, numerous impediments to the recognition that the ubiquitous magnetite-laden units and associated aluminous gneiss were hydrothermal in origin. Many metamorphic reactions form magnetite at the amphibolite to granulite facies transition, and hydrothermally-leached rocks resemble metapelite or migmatitic restite, while carbonate alteration zones may look like marble or calc-silicate rock. Non-typical metamorphic mineral assemblages, modes and colours arise when hydrothermally-derived rock types are metamorphosed. These effective markers served as tools for reliable field identification of hydrothermally-altered rocks. In our case-studies, we traced pre-metamorphic hydrothermally-driven Fe-oxide precipitation in association with sericitization, albitization, pyrophyllite alteration, chloritization, and B enrichment by mapping unusually high contents of (1) magnetite or hematite, (2) biotite, (3) albite, (4) sillimanite, (5) orthopyroxene or phlogopite with cordierite, and (6) tourmaline or kornerupine. The unveiled garnetite, tourmalinite, and aluminous gneiss had assemblages that vary according to metamorphic grade and composition. To assess if high mode of Fe-Mg-Al phases resulted from partial melting (restitic residue) or metamorphism of hydrothermal rocks, we compared leucosome mineral assemblages, shape and amount with that expected of in situ partial melting reactions. In both areas there is no compelling evidence for these units to be restites. In contrast, the presence of lapilli in garnet-cordierite-sillimanite gneiss, though extremely rare, constitutes conclusive evidence for extreme pre-metamorphic high-sulphidation alteration of a volcanic protolith, while Fe-oxides or sillimanite-bearing nodules and veins record a less pervasive alteration. Geochemical research on element mobility and mass balance calculations further testified of an hydrothermal origin for these gneisses. The magnetite-rich units, together with calc-silicate rocks, garnetite, hornblendite, albitite among amphibolite, provided effective guides to sites of fluid discharge and led to the discovery of Cu and Cu-Au showings. With the presence of highsulphidation alteration, these features suggest early Cu-Au VHMS-type alteration halos within a predominantly felsic composite volcano-plutonic arc setting for both case-studies. Evidences for subsequent F-driven orthomagmatic fluid activity are also present.

May 1, 2003

By Manjeet Chowdhry, Qingxia Liu, Phillip Choi, Zhenghe Xu

Computational chemistry methods, such as density functional theory (DFT), are powerful tools to quantify reagent-mineral interactions encountered in sulphide mineral flotation. A quantitative relationship between theoretically calculated parameters based on chemical structure of collectors and their reactivity with different metals/minerals can provide valuable insights for design and development of more powerful and tailor-made reagents offering enhanced metal/mineral selectivity. DFT calculations at B3LYP/6-311++G(3df,3pd) level were employed to elucidate the reactivity of neutral sulphide collector reagents, including thionocarbamates (TC), thioureas (TU), xanthogen-formates (XF), dialkyldithiocarbamates (DTC) and dialkyltrithiocarbonates (TTC) with different heavy metal ions (Cu2+, Zn2+ and Pb2+) in solution. The extent of delocalization of lone pair electrons of heteroatoms (attached directly to C in C=S) over C=S group was found to be the dominant factor in determining the collector’s reactivity. Order of reactivity was established as: TU > TC > XF > DTC > TTC. All the collectors showed superior affinity towards copper followed by lead. Unidentate binding was observed through sulphur atom except for xanthogen-formate for which bidentate binding mode was observed. Effect of nature of substituent groups at N and/or O atom on reactivity of thionocarbamate and thiourea was also investigated. The results obtained through DFT calculations are consistent with the experimental data reported in literature.

Jan 1, 2015

"The measurement of error in assays collected as part of a mineral exploration program or mining operation historically has been undertaken in a variety of ways. Different parameters have been used to describe the magnitude of relative error, and each of these parameters is related to the standard measure of relative error, the coefficient of variation. Calculation of the coefficient of variation can be undertaken in a variety of ways; however, only one produces unbiased estimates of measurement error: the root mean square coefficient of variation calculated from the individual coefficients of variation.Thompson and Howarth’s error analysis approach has also been used to describe measurement error. However, because this approach utilizes a regression line to describe error, it provides a substantially different measure of error than the root mean square coefficient of variation. Furthermore, because regression is used, Thompson and Howarth’s results should only be used for estimating error in individual samples, and not for describing the average error in a data set. As a result, Thompson and Howarth’s results should not be used to determine the magnitudes of component errors introduced during geochemical sampling, preparation, and analysis.Finally, the standard error on the coefficient of variation is derived, and it is shown that very poor estimates of relative error are obtained from duplicate data. As a result, geoscientists seeking to determine the average relative error in a data set should use a very large number of duplicate samples to make this estimate, particularly if the average relative error is large."

Jan 1, 2007

By Joseph Hirschi, Behrooz Abbasi, Harrold Gurley, Yoginder P. Chugh

"The research goal was to assess if analytical tool/s can be developed to quantify displacements around a geological fault as longwall face moves toward it and past it. A company was faced with crossing a 2-3 m (6-10 ft.) normal up-thrown fault in the development entries and the face while mining a 375 m (1,200 ft.) wide longwall face. A field monitoring and numerical modeling study was performed to develop data. Field measurements consisted of roof-to-floor convergence and rectangular rosettes in the immediate roof. Numerical modeling consisted of constructing a 3-D structural model using the FLAC3D software with the fault plane incorporated as ubiquitous joint. Based on analyses and field observations data, the coal company was informed of impending movements along the fault plane and likely impacts on the development entries. Additional stiff supports were installed in head gate entries around the stage loader and equipment about 60 m (200 ft.) outby of the longwall face (solid). As the longwall face approached the fault, predicted displacements were documented and manifested by severe loading on the installed supports.BACKGROUND AND STUDY OVERVIEWThis paper summarizes results of a cooperative study aimed at improving longwall mining operations in Illinois. More specifically, the study focused on: 1) In-mine measurements in development entries while mining ahead of and behind a faulted zone, 2) Making observations on stability of pillars and entries while mining through the fault, and 3) Developing simplified analytical structural models using FLAC3D to assess if predictive techniques can be developed to plan mining operations through fault zone. Available data on geometry of the fault with estimates of the cohesion and frictional parameters were used for modeling."

Jan 1, 2015

For the last few years, a new and innovative technique has been successfully used to determine refractory and castable thickness in various metallurgical vessels. The acousto ultrasonic-echo (AU-E) technique uses stress waves to detect metal penetration and delaminations within refractory linings. In addition, it is capable of measuring the thickness of refractory layers and build-up material. The inspection and measurements can be carried out while the furnace is in full operation. The present paper discusses the principles of the AU-E technique, and its advantages and limitations. A number of case studies are presented to demonstrate various capabilities of this new Non-Destructive Testing (NDT) technique.

Jan 1, 2005

By Louis R. Bernier

Since 1978, most systematic studies of AMD passive treatment with limestone drains (LD) have dealt with coal mines in the United States. The authors present in this paper the first results of a triennial study initiated in 1999 on the performance of LD installed at the Ni-Cu Lorraine old mine site in Temiscamingue during a remediation plan that involved the installation of a cover with capillary barrier effects (CCBE) over the reactive pyrrhotite-rich tailings. Typically, a LD is a trench enclosed by impervious materials filled with crushed limestone and may be oxic or anoxic. Four LD (one filled with marble and 3 with dolomite) were installed at the Lorraine site. The LD have been in operation since May 1999 and are performing differently. The most contaminated mine effluent flows south and is directed towards 3 LD filled with crushed dolomite, while a 4th LD was filled with crushed marble and installed west. The LD filled with marble has been generating maximum alkalinity since the beginning of the passive treatment. Two of the dolomite drains have been generating alkalinity since mid-summer 1999, but one is not, even if a substantial pH raise was observed. A pH above 5.5 is required usually for the dolomite drains to start generating alkalinity. The installation of LD at the Lorraine site contributes significantly to the reduction of metals and sulphates loading.

May 1, 2001

By E. Fiset, T. Hennebel, F. Verbruggen, A. Prévoteau, K. Rabaey

Arsenic (As), bismuth (Bi) and antimony (Sb) are known to affect the quality of copper deposits in copper electrowinning operations. The codeposition of As was previously believed to occur only at current densities far exceeding the range of typical current densities for copper electrowinning. In this study, we investigate the copper electrodeposition on different pretreated stainless steel (SS) substrates from bleed electrolyte in galvanostatic mode at –45 mA/cm². Scanning electron microscopy (SEM) micrographs illustrate that during the initial phases of copper nucleation and growth, the current density was locally increased due to the pretreatments. It was reasoned that the codepostion of As could possibly occur in normal electrowinning conditions, but the risk can be substantially reduced by good SS substrate handling and maintenance practices. INTRODUCTION The presence of As, Bi and Sb is known to have a deleterious effect on the copper cathode quality in copper electrowinnings (Hiskey & Maeda, 2003; Hoffmann, 2004; Xiao, Cao, Shen, & Volinsky, 2012; Xiao, Cao, Mao, Shen, & Ren, 2014; Jafari et al., 2017). They are known to influence both the chemical and physical quality of the copper as they can contaminate the copper (Jafari et al., 2017) and affect the copper deposit structure (Hiskey & Maeda, 2003; Kim, Kim, & Chung, 2009), which contributes to a degraded market value of the copper (Tuddenham, 1984). The incorporation mechanisms of these impurities are believed to occur mainly through slime inclusion (F. Xiao et al, 2012) and electrolyte inclusion (Hiskey & Maeda, 2003). Other studies suggested that codeposition of these impurities is possible by their standard reduction potential being close to the one of copper (Xiao et al, 2014). Hiskey and Maeda (2003) investigated the copper electrodeposition on a copper electrode substrate in Cu electrolytes with a Cu, H2SO4, As, Bi, Sb composition representative for commercial copper tankhouses. The combination of voltammographic techniques and Auger electron spectroscopy showed that As was the first impurity to be electrodeposited from this electrolyte, yet at potentials where the limiting current density of the copper electrodeposition reaction is exceeded. The copper tankhouses usually operate at a current density ratio of 0.3 to the limiting current density in order to achieve tolerable copper quality deposits. The codeposition of As could be considered impossible in this current density condition. However, it is known that during the initial phases of electrodeposition on foreign substrates, a substantial part of the reaction proceeds by growth of individual nuclei where the current density is locally high and diffusion limited (Radisic, Ross, & Searson, 2006). Furthermore, it was observed that copper nucleation on TiO substrates occurred preferentially in the scratched oxide free areas which could serve as parts with high localized current densities (Chang, Choe, & Lee, 2005).

Jan 1, 2019

By M. Pourkani, M. Karga, Samid Banis, Andre Laplante, G. Langari-Zadeh

"The Sarcheshmeh mine processes 40,000 t/d of ore grading 0.9% Cu and 0.035% Mo. Grinding is effected in single stage ball mills using 80 mm forged steel balls, with an average consumption of 850 g/t. One of its 5 m diameter, 8 m length ball mills was emptied to measure the ball size distribution. The broken balls were first separated from the total charge, and the remaining balls classified into five size intervals of +7O mm, -70 +60 mm, -60+50 mm, -50+40 mm, -40 mm.The charge was composed of 280,534 balls (excluding broken balls) with a total mass of 305,180 kg. It was found that 4.0 % of the balls were broken; the size distribution of the charge was also markedly different from the desired one, in particular for the small-sized balls. For instance, 9% of the balls were expected to measure 2.54 to 3.18 cm in diameter, but none was found. On the other hand, the amount of top size balls was 30% higher than expected. The radial hardness of balls, which was determined by cutting the balls in halves, showed that the hardness sharply drops when the balls become smaller than 65 mm. The unexpected ball size distribution was attributed to the rapid change in the balls radial hardness. Based on the measured ball size distribution, a new ball make-up charge which uses 80% of 80 mm and 20% of 60 mm balls instead of 100% of 80 mm was proposed and implemented. The effect of the new ball make-up procedure in terms of ball consumption and grinding efficiency is being investigated."

Jan 1, 1999

By C. Rocha R.

Petioles is a mining group with integrated operations in the smelting and refining of non-ferrous metals, and is also a chemicals producer. Peñoles is the world's foremost producer of refined silver, metallic bismuth and sodium sulphate and is the leading Latin American producer of refined gold, lead and zinc. The Met-Mex Petioles Zinc Plant commenced operations in 1973 with an annual production capacity of 105,000 t/y. Year after year the production has been increased, and at present, the production capacity is 240,000 t/y. In this paper, the leaching process, particularly the operation of the jarosite circuit and its effective removal of impurities such as arsenic, antimony, indium, selenium and tellurium, is reviewed.

Jan 1, 2006