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By P. Woo, N. Brodusch, R. Gauvin, H. Demers

The scanning electron microscope (SEM) was primary developed for imaging applications. With the introduction of the Si(Li) energy dispersive spectrometer (EDS), simultaneous imaging and x-ray microanalysis became possible. However, long working distance and high current were needed because the position and small solid angle of the EDS detector. The high spatial resolution is generally obtained at short working distance with a SEM. Unfortunately x-ray microanalysis is never performed in the best imaging conditions. The annular silicon drift detector system is inserted below the objective lens which gives a higher solid angle (up to 1.3 sr). In consequence, a lower working distance and probe current can be used. An improved spatial resolution becomes possible during x-ray microanalysis. With this x-ray detector installed on a cold-field emission scanning electron microscope, quantitative x-ray microanalysis with high spatial resolution at low beam energy and low current becomes possible with the possibility of using the various different type of imaging at the same time. Also, since the count rate can be as high as 1,500 kcps, which lowers significantly the detection limit of elements as well as the minimum feature sizes of different phases that can be distinguished.

Jan 1, 2014

By Dwayne D. Tannant

The Fox Pit at EKATI Diamond Mine reached a depth of approximately 150 m as of September 2005. The pit is designed with 11 m wide benches excavated using a double benching technique leaving 30 m high bench faces. A series of blasting tests were conducted to improve catch bench reliability and increase the percentage of benches that meet an 11 m catch width. The design changes focussed on reducing damage to the bench crest because maintaining the bench crests is the most important factor in achieving good bench reliability. The most significant improvement was obtained by raising the bottoms of the lower trim blastholes by 0.5 m. This change decreases the depth of broken rock below the final bench elevation, and consequently reduces damage to rock that forms the bench crest below. Another improvement was the use of smaller diameter (165 mm vs. 270 mm) blastholes in the A and B rows for the upper trim blast. This change reduces the charge per delay during detonation, reduces the powder factor slightly, and reduces the energy affecting the final pit wall and crest. As mining and the blast testing progressed, the portion of the bench with crest achievements (>11 m) increased from 57% to 75%.

May 1, 2006

By Y. Long

The deep-hole surface blasting technique is a prime method of iron ore mining. Blasting fragmentation is one of the important economic indicators that measures the blast method to obtain the iron ore. To improve the efficiency of the blasting method and further reduce the cost of the subsequent processing of iron ore, this paper summarizes measured data gained from a certain amount of blasting test conducted in an iron ore mine in Guangdong province, China. According to the data analysis, there are differences on iron ore blasting fragmentation by different indicators of deep-hole blasting, such as decoupling coefficient of charge, contact state between charge and borehole wall, and change of detonation position in charge. These factors were compared in terms of relevance and impact. Research shows: under certain rock conditions, the decoupling coefficient of the charge has a best range related to blasting fragmentation. Since the detonation position in charge determines the direction of propagation of the explosion stress wave through ore and rock, bottom initiation and mid initiation will help to improve the iron ore blasting fragmentation in joints fractured rock and ore. The research conclusions have important application value for program design of iron ore surface blasting and to guide other types of rock surface blasting.

Aug 1, 2013

By A. A. Abdul-Latif, A. Sahin

"The phosphate deposit, located in the Abu Tartur plateau between the Kharga and the Dakhla Oases in the southern part of the Western Desert of Egypt, is the largest of its kind in the country. The phosphates are found in two horizons referred to as the Lower and Upper Phosphate Horizons within the Late Campanian Sibaiya Formation which belongs to the Nubia Group.This paper presents the results of a geostatistical study on the main phosphorite bed at the base of the Lower Phosphate Horizon which contains almost all the commercial reserves in the area. After semivariogram modeling for the phosphate thickness and accumulation, ordinary block kriging was employed to estimate the values of these variables in blocks of400 m by 400 m dimensions. The kriging results, which are presented in the form of contour maps, can be of considerable use in both future exploration and exploitation of the deposit. The grade-tonnage relationship based on the grade estimates derived from the corresponding thickness and accumulation estimates indicates the existence of 453.9 x 105 tonnes of phosphate above a cut-off grade of 18% P2O5. The mean grade of this tonnage has been estimated to be 25.77% P205"

Jan 1, 1990

By A. Galibois, R. Singhal

"This paper highlights some of the potential application areas of knowledge-based systems in the mining industry. The basic theoretical principles associated with knowledge-based systems are discussed and the justification for mining applications is given. The paper concludes with a brief description of a prototype knowledge-based system applied to scraper selection that was developed at Université Laval on a LISP machine. IntroductionThe beginning of Artificial Intelligence coincided with the conception and development of the first computer systems some thirty years ago. At that time researchers were euphoric about the possibility of modelling the human reasoning process. Soon, however, they discovered that the combinatorial aspect of the set of possible solutions to a particular problem did not permit an in-depth evaluation.In the mid-60s researchers started to look at the heuristic approach because it was more suited to human behaviour with its congnitive abilities (i.e. representing, reasoning, problem solving and advising). The heuristic approach allows possible results rather than exact solutions and it is more rapid and cost effective than the exhaustive combinatorial analysis. The heuristic approach did allow some noticeable progress in the seventies with the development of the first expert system called MYCIN with the objective of diagnosing blood infection diseases."

Jan 1, 1988

By T. Lamb, T. Aston

"The Gays River Mine is located within a complex hydrological regime and underground mining environment. Early in the mine history, the operation was' affected by an inability to control mine water inflows. More recently, the reopened mine operation had been unable to maintain consistent drainage of groundwater to the mine workings and sustain low groundwater levels.In 1992, a series of investigations were completed, which in part Were funded under the Canada-Nova Scotia Mineral Development Agreement. The studies undertaken included: hydrochemical and drainhole well screen assessments, an air photo study of sinkhole features, numerical modelling studies and a major piezometer installation and overburden soil study. The results indicate that the water draining to the underground workings is comprised of two distinct components: precipitation over the drawdown cone catchment area and seepage from the nearby Gays River. In addition, a third ""balance"" component was' also found, which represents uncertainties in the areal extent of the drawdown cone and river seepage components.After outlining the history of the groundwater problems experienced at the Gays River Mine, this paper examines the various studies undertaken during 1991-1992 and concludes that control of groundwater levels in the mine area is achievable. A number of recommendations are also proposed for future study ."

Jan 1, 1993

By Kazutoshi Haga, Batnasan Altansukh, Atsushi Shibayama, Ryuji Oinuma

"Recently, the arsenic grade in copper ores has been increasing year by year. Arsenic bearing minerals (enargite (Cu3AsS4) and tennantite (Cu12As4S13)) coexist with typical copper minerals such as chalcopyrite (CuFeS2). The removal of arsenic from copper ores that contain relatively high arsenic content is essential due to its adverse impact on the environment and the resulting economic consequences. In this study, arsenic removal and dissolution behaviour of Cu and As from enargite (Cu3AsS4) were investigated using ferric sulphate (Fe2(SO4)3) solutions containing sodium chloride under high pressure oxidation conditions. The effects of numerous parameters including the concentration of Fe2(SO4)3 and NaCl, temperature, total pressure, leaching time and particle size were studied while other variables such as pulp density and stirring speed were fixed at 100 g/L and 750 rpm. The results showed that more than 60% of the copper was dissolved in a 0.1 M ferric sulphate solution under the high pressure oxidative conditions, whereas the leaching rate of arsenic was less than 20%. SEM observation revealed that elemental sulphur was deposited on the surface of enargite forming a passivation layer and the residue was agglomerated. Those phenomena may cause a decrease in the copper leaching rate. It was found that more than 80% of copper was dissolved in the ferric sulphate solution in the presence of 0.34 M sodium chloride under the conditions optimized, whereas the dissolution of arsenic in the mixture did not exceed 2%. XRD analysis of the solid residues from the leaching experiments used ferric sulphate and mixtures of ferric sulphate and sodium chloride showed arsenic to be present as scorodite (FeAsO4).INTRODUCTION In recent years, there has been an increase of the arsenic (As) content of copper ores due to the gradual depletion of high grade copper ores. In some copper deposits, arsenic occurs in the form of minerals such as enargite and tennantite. The removal of arsenic in ores containing copper is critical to the production of pure copper and the management of the environmental challenges caused by the smelting process. Due to the environmental risk caused by arsenic emission and the deteriorated quality of the copper product, smelting of enargite concentrates is not an effective method for the extraction of copper (Padilla et al., 2010; Safarzadeh et al., 2014; Long et al., 2012). Therefore, a number of studies have been carried out to develop arsenic removal technologies from copper ores using various methods such as hydrometallurgy (Curreli et al., 2009; Tongamp et al. 2010), pyrometallurgy (Dalewski., 1999; Padilla. et al, 2012) and bio-oxidation (Ehrlich, 1964; Sasaki et al., 2010). Several hydrometallurgical leaching processes like sulphuric acid, alkaline sodium sulphide and sodium sulphate and ferric sulphate leaching have been developed to treat enargite ores and concentrates. The alkaline sodium sulphide leaching process has been developed for the removal of arsenic from enargite (Anderson, & Twidwell, 2008; Parada et al., 2014). The mechanism of the dissolution of arsenic from enargite in sodium sulphite solution is"

Jan 1, 2016

By Navid Bahrani

The grain-based model (GBM) has resolved the difficulty of matching both the directtension (sc) and unconfined-compressive (st strengths of typical brittle rock by providing a synthetic material that mimics deformable, breakable polygonal grains cemented along their adjoining sides with deformable, breakable interfaces modeled as smooth-joint contacts. In this paper, a GBM utilizing a parallel-bonded base material is calibrated to match both st and sc of Lac du Bonnet granite and then used to simulate a Brazilian test. The Brazilian strength (sB) is slightly overestimated and the failure mode includes ductile post-peak response that is not representative of what occurs in laboratory Brazilian tests. By reducing the grain tensile strength, grain failure occurs during the Brazilian test and a more realistic failure mode that includes brittle post-peak response is obtained. However, the unconfinedcompressive strength of the modified material is too low. Sensitivity analysis on the grain and grainboundary strength properties demonstrates that the grain tensile strength controls the sB/sc ratio. Because the grain strength is controlled by the parallel-bond properties and the lowest achievable st/sc ratio in a parallel-bonded material is ~0.25, it is concluded thatsc, st and sB for a typical brittle rock cannot be matched with a GBM that utilizes a parallel-bonded base material.

Jun 1, 2012

By F. E. Lee

The following outline gives a brief account of some of the ways in which microscopy is applied to the problems arising from the various operations of the Tadanac reduction works, at Trail, B. C. The Sullivan ore is a very fine-grained mixture of galena, marmatite, pyrite and pyrrhotite. The separation of minerals associated so intimately is a difficult task and requires careful control. Various oils and reagents are used in the process as developed, and it is essential that the operators have a means of control which shall be rapid, and at the same time, approximately correct. This result is obtained by microscopic analysis in the following manner: The operator places a quantity of the material upon a slide, a drop of water is added, and it is covered with a cover glass. Upon examination with transmitted light, the zinc mineral particles appear reddish, the ordinary gangue colorless, the lead and iron sulphides opaque. This method has proved of great assistance both in the development and in the operation of the present method for concentrating Sullivan ore. The miscroscope has thus become as much a part of the metallurgical equipment as the balance and burette. The microscope used in the laboratory is a Fuess "petrographic" with a specially-made vertical "illuminator" by Bausch & Lomb, with the usual accessories.

Jan 1, 1924

By STEPHEN V. FORGERON

The Loch Lamond celestite properties in central Cape Breton Island were mined by Kaiser Celestite Mining Limited from 1970 until 1976. Poor market conditions in J976forced operations to cease. Kaiser holdings included the Lake Enon, MacRae and A mac prospects. A total of about 272,000 tonnes of raw celestite have been mined. Celestite deposits are situated in the Loch Lamond Basin, specifically in Lower Windsor sedimentary rocks. Of the five formations in the Lower Windsor Group, celestite is found in the upper four. Celestite in the Enon Formation occasionally replaces shale that separates stromatolitic dolomite columns; elsewhere in the formation it occurs in association with siltstone and gypsum. Jn the B2 Limestone Formation celestite fills pores or grades between limestone and gypsum. It replaces both limestone and silty limestone conglomerate in the Loch Lamond Formation; this limestone is of unusually high grade (60 to 70% SrSO,J for the area. Evidence indicates that the Uist Formation may hold important celestite reserves. Original celestite mineralization probably resulted from evaporation of seawater on mudflats or 'sabkhas'. Secondary mineralization also may have occurred. Strontium ions could have been leached from pre-existing concentrations and overlying gypsum, moved downdip in groundwater and combined with sulphate rich waters to deposit as celestite in porous B2 limestones.

Jan 1, 1984

By Arthur Lieu

The mill effluent treatment circuit (Bulk Neutralization (BN)) in the Cameco Key Lake Operation was modified in 2008 to enhance the removal efficiency of selenium (Se) and molybdenum (Mo) from the mill process water. This modification was completed in part due to increased knowledge of the effects these elements have on biota. In addition, legacy effects from the historical operation of the Key Lake mill in regards to Se and Mo were shown to have an effect on the regional biota in the downstream receptors. This was a challenging initiative as there was no off the shelf technology available and the removal process had to be incorporated into an existing (brownfield) process. These modifications have resulted in significant reduction in the concentration of these elements in the Key Lake mill effluent. The removal efficiency for Se and Mo in the modified circuit has increased to 95% and 75%. As a result, concentrations of Se and Mo are now consistently less than 0.4 mg/l and 0.02 mg/l. In addition, the Se and Mo precipitates formed were extensively studied to ensure long-term geochemical stability in the Key Lake in-pit tailings facility. This presentation will provide additional detail on the hydrometallurgical removal mechanisms and process modifications required in the Key Lake BN circuit to remove these elements to trace levels.

Aug 1, 2010

By David Morley

This paper considers the ideal truck-excavator combination, defined as the combination resulting in the lowest direct unit cost, in consideration of multiple haul scenarios characterized by different haul distances, material and equipment availability. Through the application of Monte Carlo simulation, selected for its unique ability to handle the uncertainty of activity durations, the ?four to six passes? loading rule is shown to not correlate with the selection of the minimum cost fleet. Additionally, through the results of the simulation it is determined that the haul truck capacity has a greater effect on the overall efficiency of the system than does the excavator capacity. As a result, in order to arrive at efficient operations, the entire earthmoving system must be viewed as whole, namely, considering haulers together with excavators, as opposed to the popular method of first selecting a loading unit and then selecting a hauler obeying the ?four to six passes? loading rule. Furthermore, truck utilization and excavator utilization exhibit an inverse relationship and neither directly correlates with the overall efficiency of the earthmoving operation. The following conclusions are drawn: first, with limited financial resources, it is more valuable to increase hauling unit size before increasing loading unit size and second, predefined rules or generalizations, not based on evidence, potentially eliminate optimal truck excavator combinations from being considered.

Aug 1, 2013

By H. Nakano

The codeposition behavior of impurities such as Ag, Bi, Fe, Ni, Pb and Sb with Cu was investigated galvanostatically at 5-3000 A/m2 using a Pt cathode at 60 °C in acidic copper (I) chloride (cuprous chloride) solution at pH1-2 containing 1.0 mol/L of Cu+ and 4.9 mol/L of Cl-. The impurities were classified into two groups: Group I (Ag, Bi) which codeposits with Cu as a metal, and Group II (Fe, Ni, Pb, Sb) which is slightly involved in the deposited Cu in nonmetal form from the electrolyte. Silver and Bi in Group I behaved as more noble metals than Cu, and significantly codeposited with Cu, showing typical features of regular-type codeposition. When Cu was deposited dendritically, the Ag and Bi content in the deposit increased with increased duration of electrolysis as a result of decreased net current density caused by increased cathode area. The current efficiency for Cu deposition in impurity-free solution was 95-100% over 100-1000 A/m2, but it abruptly decreased at above 1000 A/m2 when the limiting current density of Cu was attained. Although Fe, Ni, Pb and Sb in Group II were involved to 0.01-0.02 mass% in the deposit, they had no influence on the current efficiency or morphology of Cu.

Jan 1, 2007

By Craig Ford

Inmet Mining is committed to implementing the highest corporate responsibility standards in its mining operations worldwide. Inmet is 100% owner of Minera Panama, a world-class copper project that is currently in the feasibility phase in north-central Panama. Panama has limited experience with modern mining, limited mining capacity, and the project context involves significant social, environmental and political complexity. The Project area is remote with recent in-migration of latino and indigenous people, informal and small-scale mining, local subsistence populations and considerable biodiversity value, coupled with a complex jurisdictional setting. In short, it is increasingly the kind of project mining companies are taking on because the easy projects have already been developed. With such challenging conditions, anticipating and managing social risks is critical to effective project management. To this end, between August 2007 and the third quarter of 2009 Inmet seconded Monkey Forest Consulting Ltd to the project to assist Minera Panama in building and implementing an effective, early phase external relations strategy. The team was also tasked to find and develop a locally based team that could sustain success through project development and into operations. Today?s presentation was created by Inmet and Monkey Forest and describes some of the lessons learned in implementing an effective early phase process for managing social issues.

May 1, 2010

By C. Barnett

"A description of the Geco orebody has been given by W .L. Brown and R.C.E. Bray (1). The mill flowsheet and equipment were described by M.J.S. Bennett, D. Wild and C. Lawton (2). Mill capacity is now 4, 150 tons per operating day of copper, silver, zinc and lead ore. A recent flowsheet has been published in the - Canadian Mining Manual (1966).Soon after the start of production in September 1957, it became apparent that large tonnages of sand would be required by the mine for backfill pruposes. Initial experimental work on the preparation of sand fill from the flotation tailings was begun in late 19 59. Cyclones of local manufacture, in a variety of sizes, were tested quite successfully. There were, however, several obvious advantages with some of the custom-built cyclones and a recommendation was obtained from the Techniquip Company. A single Krebs D-10-B cyclone was tested experimentally in 1960.INITIAL TESTWORKExperimental results showed that with our relatively coarse grind (in the order of 53 % minus 200 mesh) 75 - 80% of the flotation tailings could be recovered as backfill sand with one stage of treatment. Percolation rates of four inches per hour were obtained with cyclone inlet pressures in the range of 20 - 25 psi and feed densities of 20 - 23% solids."

Jan 1, 1968

By Pierre Gy

"Abstract - This paper deals with industrial complexes such as: (1) a mine producing metal-bearing ore and a furnace(s)/converter(s) where the ore is melted into metal, either directly, or after a mineralurgical concentration; and (2) quarries producing the raw materials required for the manufacturing of cement and the kilns to which they are fed.Each mine or quarry operation results from the exploitation of a mineral deposit. This deposit is never homogeneous. The raw materials which are extracted from the mine/quarry can never be safely fed to a "process" such as a cement kiln or a metal smelter, because the devices involved lack the flexibility required to absorb a very inhomogeneous feed. Furnaces and kilns are known to be very sensitive, sometimes dangerously so, with regard to deviations from a certain ideal feed composition.The purpose of this paper is to present the conditions required to optimize the operation of such a complex, so as to maximize the production, the quality of the product, as well as the profit generated. Two key operations are involved: sampling (to know accurately the materials being dealt with) and bed-blending (to achieve the desired degree of homogeneity). The theories of sampling and bedblending have been developed by the author and presented in various books (Gy, 1992, 1998)."

Jan 1, 1998

By J. N. Cram

"The comments given are to help allay generally accepted ideas that the handling of arsenic as arsenic-trioxide (As2o3J in and from off gas pyrometallurgical operation fumes is difficult, hazardous and expensive. It need not be any of these things if the basic and rather unique chemic3l and physical properties are understood and taken care and advantage of through present day technologies. These particular characteristics are:-(1) As2o3 sublimes and re-condenses, at a relatively low temperature;(2) As2o3 is, for practical in-plant purposes, insoluble in water at ambient temperatures and quite soluble in water just below the boiling point;(3) residual suspended and dissolved As 2o3 can be removed from water by complete dissolution with very little sulfuric acid, followed by the addition of small amounts of ferrous sulfate and calcium chlorate, with oxidation to the ferric and arsenite state and precipitation of an insoluble ferric calcium arsenate, thereby lowering the As2o3 content of solutions to acceptable levels. Even lower levels of non-toxic forms of arsenic solids and residual As2o3 in the water solutions can be attained by also using phosphate, and lime, along with the above.A background re past arsenic processing methods, present day operations, plus predictions re future trends, and hazards, are outlined."

Jan 1, 1979

By Yuwang Wang, Yanggeng Tan, Kezhang Qin, Zengqian Hou

Abstract- The large Derni Cu-Co (-Zn) deposit in Qinghai Province exhibits unusual geological features, and its genesis is controversial. Based on previous research and detailed field investigations, petrographic studies of the host volcanic rocks, isotope and trace element geochemistry of the sulfide ore, and comparison with typical ore deposits, this deposit is a VHMS (submarine volcanichosted massive sulfide deposit) type. This argues against previous interpretations of a magmatic or a hydrothermal replacement origin. Systematic rock, mineral and geochemical studies of the host serpentinites of the ore district indicate that the protoliths of several types of serpentinites that are widespread in the ore district are mainly ultramafic volcanic rocks. The mineralization formed within an ultramafic volcanic breccia, or between the breccia and its overlying Mg-rich carbonate rocks and volcanic sedimentary rocks. The ore-forming components were derived mainly from ultramafic rocks and partly from mafic rocks. The ultramafic rocks are MgO-rich, CaO-poor with a high MgO/FeO ratio, and the mafic rocks are rich in Na2O and poor in K2O. The chemical composition of the ultramafic rocks is similar to that of volcanic peridotite, or komatiite. The volcanic rocks that host the Derni deposit are among the most basic host rocks known for VHMS deposits, and the Derni deposit represents the most basic member in the VHMS deposit spectrum.

Jan 1, 2000

By J. Chao, C. Tan, N. Stubina

"Since J978, Falconbridge Limited has operated two electric furnaces at its nickel-copper smelter in Sudbury. As part of its S02 Abatement Program, the smelter has undergone many changes over the last seven years.This paper describes the impact of these changes on the operation of the furnaces. Some of the topics to be covered include: the installation of sidewall copper coolers; current operating conditions; and furnace heat and mass balances. HistoricalFalconbridge began smelting ores in the Sudbury area in 1930. The original smelter consisted of a 1.3 m by 3 m blast furnace and two 4 m by 6 m converters. The blast furnace was supplied with untreated mine are and molten slag/matte was discharged into a round settler.In 1933 the smelter began treating flotation concentrates. The concentrates were mixed with fine magnetic ore and flue dust, then sintered on down-draught Dwight Lloyd machines. This provided an agglomerate suitable for furnace burden which was charged to the blast furnace while still hot.Between 1930 and 1954 nickel production was increased by lengthening the 3 m furnace to 4.6 m, then to 6 m, and later by constructing additional furnaces. By 1958, the plant consisted of one 7.5 m blast furnace, a settler, and three 4 m by 9 m converters."

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