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By A. A. Tytko, T. S. Golosinski

"The paper discusses the accuracy of magnetic inspections of corroded hoist ropes. It quantifies the error of measured LMA (loss of metallic area) caused by presence in the rope of ferromagnetic products of corrosion. The paper concludes that in mining practice this error is not significant. Hoist Rope Corrosion and its AssessmentCorrosion is one of the most common forms of wire rope wear. For ropes working in wet mine shafts, ropes used by the fishing industry and, in general, ropes working in humid and chemically active environments, corrosion wear is usually the prime reason for rope discard. In most mining applications, rope corrosion is accompanied by fatigue cracking of wires, abrasion of external wires, internal nicking and other forms of wear.Quantification of corrosion damage in ropes using standard inspection procedures and examination methods is very difficult. Qualitative comparisons are sometimes used to describe the degree of rope corrosion to compensate for the lack of quantitative measures (SABS 0293, 1996). If available, the results of magnetic examinations of ropes may be of help in assessing their corrosion weakening.Magnetic rope examination requires that the rope first be magnetized. After that, the rope magnetic flux and the leakage flux along the rope are measured. The first is assumed to be directly proportional to rope metallic area (LMA) and its changes are indicative of the rope’s loss of breaking strength (LBS). Existence of the second indicates existence of local faults (LF) in the inspected rope. As the corrosion of rope results in development of corrosion cracks and in loss of rope metallic area, both the LF and the LMA should be used to quantify the level of rope corrosion. More specifically, the changes to the amplitude of the LF signal are considered to provide qualitative information on rope corrosion (Hansel et al., 1990), while those of the LMA signal are believed to provide quantitative information (Geller and Rousseau, 1990; Golosinski, 1996)."

Jan 1, 1999

By W. J. Farley

Location and History The Sherritt Gordon mine is in northern Manitoba, one hundred miles north of The Pas and forty miles northeast of Flin Flon. The original discovery was made by a Cree indian, Philip Sherlett, in 1922. The claims lapsed in 1924 to be re-staked and optioned by various mining groups who carried out a certain amount of development work before relinquishing their options. In 1927 the present Company, Sherritt Gordon Mines, Limited, was formed to take over the property. Production commenced in 1931, but in the following year operations were suspended and it was not until 1937 that the prevailing price of copper pemitted resumption as an economic operation. The mine has operated continuously from that time to the present. Total production to the end of 1947 has been: Copper . . . . . . . . . 301,813 . .,345 pounds Zinc . . . . . . . . . . . 112,636 tons of concentrat (50% zinc) Gold . . . . . . . . . . 83,070 ounces Silver . . . . . . . . . 2,651,317 ounces General Geology The consolidated rocks in the vicinity of the mine, all of Precambrian age, are a series of gneisses and form a part of a great area of what are known as the Kisseynew gneisses. The Sherritt is the only known economic base-metal deposit to occur within the Kisseynew series. Extreme metamorphism has produced recrystallization that has imparted a decided igneous-like texture to many of the units. However, the gneisses are predominantly of sedimentary original although the most basic member, a hornblendegarnet gneiss, is considered to be an altered basic flow. Figure 1 illustrates the intricately folded structure and the succession of roe types. The footwall enclosing members are of sedimentary origin and represent quartzite and arkosic and greywacke derivatives. The contact footwall member is gneissic quartzite, a medium to coarse grained rock composed mainly of quartz with minor altered feldspar (orthoclase and plagioclase), muscovite, chloritized biotite, and magnetite. Most phases of this unit show varying degrees of granitization.

Jan 1, 1949

By J. C. Gathje

Newmont&apos;s Phoenix Project is located near Battle Mountain, Nevada and is scheduled to produce copper concentrates containing high precious metal values. High temperature pressure oxidation (PDX) of the concentrates was considered as a treatment option during process development. The metals content in Phoenix concentrates range from: 15-25% for Cu, 1-10% for Zn, 0-2% for Pb and ?27% Fe. The precious metals content of the Phoenix concentrates can range up to ?300 g/t Au and >3,000 g/t Ag. As a consequence it was necessary that any process for consideration should have the capability of recovering both the copper and precious metal values. Typically, gold can easily be leached from the autoclave discharge solids, but silver is chemically bound with the jarosite formed and cannot be directly leached. Laboratory investigations led to the development of a patented PDX process that minimizes the formation of jarosite so that the silver can be leached easily along with the gold. The process was confirmed with extensive pilot plant testing. Excellent solution extraction of copper and zinc was achieved, and both iron and lead were precipitated in the PDX residue. The process produces clean PDX discharge liquors with very low iron concentrations. As an example, conventional PDX techniques resulted in pregnant liquors containing ?5 g/L Fe. However, the Newmont process, which controls the iron and sulfate species, achieved high iron precipitation in the PDX solids and pregnant liquors containing <0.5 g/L Fe. High gold and silver recoveries were achieved by direct cyanidation of the PDX solids. This process has the added benefit of producing PDX solids that demonstrate superior settling and filtration characteristics.

Jan 1, 2006

By A. G. Roach

HISTORY AND LOCATION SEAL HARBOR GOLD MINES, LIMITED, was incorporated in January, 1934, to take over 116 acres of mining lands in the Stormont gold district, Guysboro county, Nova Scotia. The nearby ten-stamp Mulgrave mill was also purchased, and since that time 974 acres of adjoining properties have been secured from the Government by direct lease. The property is served by a motor road and is about two miles from the village of Goldboro, situated on the shore of Isaac&apos;s harbour. The bulk of ?the supplies are brought in by coastal steamer from Halifax, a distance of about 100 miles, since the nearest railway connections are at Antigonish, some 40 miles distant. EARLYY WORK The Seal Harbor properties include the old Partington and Beaver Hat mines. A small tonnage of ore was mined from each and treated on the properties in stamp mills, which were later torn. down . A survey of old records shows that this ore averaged about $8.00 gold per ton. Development work by the present Company was confined to the 100-foot level until February, 1935, but after that rime the incline shaft was deepened to 425 feet and the 300-foot level was explored east and west of the shaft. Six belts of ore were intersected to the west of the shaft. The ore from these belts was hand sorted and the ore portion was put through the 10-stamp Mulgrave mill to defray operating expenses and to serve as a sample of the deposits. The average recovery per ton from this sorted ore was $6.10. Samples of the ore were sent to the testing laboratories of the Mines Branch, at Ottawa, and of Canadian Industries, Limited, at Toronto. Recommendations from both of these authorities were for removal of the coarse gold by concentration and barrel amalgamation, followed by cyanidation of the residue.

Jan 1, 1937

By H. Qi, J. L. Feng, D. J. Li

"In the present paper, the characteristics of the granite burst under loading/unloading conditions was studied by means of both laboratory experiment and finite-discrete element method (FDEM). After gaining the mechanical properties of the granite samples under uniaxial compression conditions, the parameters taken as input arguments in the FDEM modelling were then carefully calibrated so as to provide some basic data including Young’s modulus, Poisson’s ratio, uniaxial strength, Lame constants, cohesive strength, and frictional angle for further being used in simulating granite bursts. All the simulating results by the FDEM were basically in agreement with that obtained from the uniaxial compression test and triaxial granite bursts in laboratory, respectively. This study shows that that such computational mechanics of discontinua can be employed to gain powerful insight into the failure mechanism of granite burst, which could also be a useful tool to clarify the collapse mechanism of rock structures in rock engineering design and rock test scheme optimisation. INTRODUCTIONBased on discontinuum state a priori, discontinuous modeling techniques that are commonly referred to as discrete element methods (DEM) treat the material directly as an assembly of separate blocks or particles, which was originally proposed by Cundall (1971) and Cundall and Strack (1979) from the viewpoint of analogous molecular dynamics simulation to better account for and understand the interaction between the blocks. The distinct feature of these formulations is that a constantly changing problem of geometry and contact conditions can be addressed by solving the equations of motion using an explicit time marching scheme (most often in a ‘leap-frog’ format), while updating contact force histories as a consequence of contacts between different discrete elements and/or resulting from contacts with model boundaries (Bicanic 1998). The most notable implementations of DEMs are arguably represented by the universal distinct element code (UDEC) (Itasca Consulting Group Inc., 2013) and the particle flow code (PFC) (Itasca Consulting Group Inc., 2012). Another formulation is the discrete crack framework that is based upon some criteria for an advancement of crack front, which is coupled with extensive local and global re-meshing while simulating by numerical methods such as finite element technique, commonly using fracture theories. Certainly, it is relatively easy to trace the propagation of single crack front governed by some principles of energy release rates (Ingraffea 1997) but tracing of multiple cracks leads to topological and algorithmic complexities. Otherwise, there is no consideration of interacting cracks in these formulations of finite element or enhanced finite element techniques (e.g., in XFEM and ABAQUS)."

Jan 1, 2015

By M. S. Badollet

"IntroductionASBESTOS FLOATS may be defined briefly as blends of air-borne particles of fibrous asbestos and dusts produced during the milling stages and collected by Cottrell precipitators, dust sheds, or bag-houses.The various grades of asbestos floats on the market contain fibrous asbestos particles ranging in length from microscopic to approximately 1/4-inch. The fines or dusts present in the floats are from 40 microns to 2 microns or less in cross-section.Airborne asbestos particles are of diverse length because they are collected at numerous places in the mill. There are: (1) dusts removed from dry rock storage bins, (2) dusts removed from rock and fiber screens, (3) particles from the tops of collectors, and (4) fines removed by suction from the processing equipment. Sometimes the airborne particles are kept segregated, so that there is a partial separation by gravity. This is accomplished by a series of dust chambers enclosed in a long, rectangular building. The longest and heaviest particles fall nearest to the air flow entrance, the smallest at a point farthest away and nearest the exit. Sometimes the air from the dust chamber building is passed through a series of bag-houses or electric :precipitators ,to collect the extremely fine particles which normally escape to the atmosphere."

Jan 1, 1952

By H. R. Butler

"The Ontario Division of Inca Metals Company, a Unit of Inca Limited, operates eleven mines, four mills, three refineries, one smelter and one iron ore recovery plant. All but one mine, mill and refinery are located within a fifty kilometer radius of Sudbury, Ontario. A mine-mill complex is located some 100 kilometers west of Thunder Bay on the shore of Lake Shebandowan and a nickel refinery at Port Colborne.During the past 10 years the use of recycled water in our milling operations has increased to more than 95% at each mill. This high degree of water reuse has reduced the (a) need for fresh water and (b) the contaminant level of the downstream aquatic environment. The aggregating of effluents in a common receptor provides a process water having a consistent quality thereby minimizing upsets in mill metallurgy while concurrently improving the operating economies and the downstream aquatic environment."

Jan 1, 1980

By G. Lucas

"Material substitution occurs continuously in response to competitive and economic pressures. Technical development can accelerate or slow substitution by improving the performance of the invading or defending material. The choices are seldom simple and have to be made in the context of continuous commercial change.The development and commercialization of a new aluminum material is examined. The material has been introduced into· several different markets, so it is possible to compare and contrast the degree of success obtained in each.IntroductionAluminum-based materials have been in use for over one hundred years and , therefore, the development of a new family of alloys is rare. In the early 1970s, Dr. L.R. Morris and his coworkers at Alcan&apos; s Kingston Research Centre started work on what was, at the time, something of a scientific curiosity-a family of alloys strengthened by an unusual mechanism.This paper deals with the development and commercialization of what became known as the Alcan 255 alloys"". These alloys have found uses in several markets, usually as improved substitutes for existing materials. Forecasting the usefulness of a substitute material in an existing marketplace is difficult, in part, because even material users are seldom able to specify precisely their requirements. This uncertainty can cause the failure of some substitutions but can also lead to opportunities which were not initially obvious.Technical BackgroundPure aluminum is a soft, weak material. It can be strengthened by the addition of various alloying elements and by work hardening. Alloying elements usually act by forming solid solutions which are stronger than the pure metal or by precipitating during heat treating or aging and so preventing the easy movement of dislocations during deformation. Elements which can perform either role had been investigated for decades and were thought to offer little chance of technical breakthrough in 1970. An outgrowth of the then new and exciting research on directional solidification seemed, however, to offer such promise.Some aluminum-iran-manganese alloys will solidify under certain conditions as &apos;coupled growth&apos; eutectics (Figs. I and 2). The microstructure shows one phase growing as long rods through the other. This is an uncommon structure and it was investigated to see if it had equally unusual properties. On deformation by rolling the rods were broken up into small equiaxed , evenly-spaced particles (Fig. 3). Materials with this structure were found to be stronger than other alloys with similar amounts of alloying addition, and to resist thermal softening remarkably well. This combination of properties was thought initially to be due directly to the particles by a dispersion strengthening mechanism, but later this was found not to be strictly true."

Jan 1, 1987

By Z. D. Hora

Sand and gravel resources of the southern coastal region of British Columbia may be linked to various episodes of Wisconsin glaciation. During Wisconsin and probably earlier times, the Fraser Lowland and coastal areas were subjected to repeated glaciations separated by non-glacial intervals. Each major glaciation was accompanied by isostatic and eustatic changes in sea level up to 200 m or more. As a result, the Lowland was covered by the sea during much of Quaternary time. Because the Fraser Lowland is surrounded on two sides by high mountain ranges, glaciers terminated in the sea during their maximum advance. Therefore, meltwaters released during deglaciation, together wit h retreating glacier ice, could produce widespread and extensive sand and gravel deposits both along the coast and throughout the Fraser Lowland and adjacent areas.

Jan 1, 1984

By J. Pepin

When using alternating current submerged arc welding (SAW) to produce pipes from microalloyed linepipe steels, it is critical to balance penetration depth and deposition rates, in order to minimize the number of weld passes while still maintaining good heat affected zone (HAZ) microstructures and properties. A series of bead-on-plate (BOP) submerged arc welds were performed on X70 steel, using different waveform variable settings (i.e., balance, offset and frequency). Weld bead cross-section profile deposition and penetration areas were measured, and both Vickers hardness and Charpy V-notch impact testing were performed. Both single electrode and tandem electrode welds were evaluated.

Jan 1, 2011

By J. Font

The RAF or copper fire refining process at the Caletones smelter of CodelcoChile consists of several pyrorefining stages that successively lowers the levels of S, Fe, Pb, As, Sb, Te, Se and to some extent 0 in the copper melt, allowing the production of high quality fire-refined copper of 99.93 % purity (RAF copper). This chemical feature of the RAF copper is only achieved by quite long processing times, and a considerable consumption of fluxes and fuels in the RAF vessels. The main goal of this study was to improve the RAF process performance by thermodynamic considerations and industrial scale tests, i.e., an in situ approach for the process as featured by intensive sampling, characterization and subsequent modifications. Thus, both theoretical and industrial data were derived, and based on kinetic and thermodynamic evaluations, a higher operational standard was achieved for the RAF process. These new operational practices allowed enhancing the overall economic of the RAF process, by reducing the time and operational costs, and consequently increasing the availability of the vessels.

Jan 1, 2007

By N. Geoffroy, E. Benguerel, G. P. Demopoulos

In the late 1990s, a chemical process to remove mercury and selenium from weak sulphuric acid solutions was patented and implemented in the CEZinc refinery in Valleyfield, Quebec. The CEZinc process comprises two stages. In the first one, sodium sulphide is added to the weak acid solution in order to precipitate the soluble mercury. The solution is then treated with sodium dithionite in order to reduce the selenium to elemental form. Because of recent changes in the composition of the industrial solution, a project to study the background chemical reactions was started. In this paper, a review of the background chemistry is presented on the basis of several eh-pH diagrams on one hand, while on the other experimental results are reported dealing with the reaction of selenium (IV) species with either dithionite, sulphide or a combination of the two. According to this work, elemental selenium enjoys a wide pH-eh range stability with selenium sulphide being metastable. Selenium (IV) in single metal synthetic solutions was found to be reduced - to elemental state - at ambient temperature down to ppb range with dithionite as long as the stoichiometric ratio (dithionite/selenium) was in excess of two and the pH < 1.7. Under these conditions the reaction was very fast reaching completion within one minute. Sodium sulphide proved equally effective in reducing selenium (this time as selenium sulphide) to ppb range from single metal solutions. However, in mixed Se-Hg solutions deviations from this "ideal" behaviour was observed resulting in higher levels of residual soluble selenium left in solution.

Jan 1, 2008

By J. ?H. Chen

Remote sensing technologies have been applied to numerous fields and already benefited those in improving efficiency and recognition accuracy. Change of streamflow can be devastating to residents living along riversides. Still it is difficult to detect such deathly change in large area scale by traditional field surveys. The research aims at provision of detecting streamflow change using a mathematic method based on remote sensing technologies. The scope is on remote sensing stream images taken during the invasion by Typhoon Morakot, bringing one of the major catastrophes to Taiwan. An algorithm was adopted to deal with streamflow recognition on RGB images. The algorithm is capable of yielding change measured by meters and illustrates how main streams shift. An practical example for the Baolai area surrounded by Laonong stream shows that the streamflow moved 88 meters (36 pixels) toward the downtown area during the invasion by Typhoon Morakot. In addition, the results highlight all dangerous zones (scouring zones) for residents to prevent further potential damage.

Aug 1, 2013

By Michael Cullen

The Quinsam Coal Mine is in the process of extracting a panel beneath the mine access road. To prevent damage to the road, and adjacent powerline, it was necessary to establish a ?protection zone? within which the extent of mining would be limited. The protection zone is analogous to the setback limit. For economic reasons it was desirable to make the protective zone as small as possible, and with the greatest extraction ratio possible. The size of the protective zone was established by determining the angle of critical deformation using the numerical model FLAC, coupled with field data on subsidence from the Mine. The angle of critical deformation (defined as the angle, measured from the vertical, at which intolerable damage is sustained by a structure) was determined to be between 0 and 5 degrees. The allowable extraction ratio in the protection zone was established using the ARMPS method of pillar design coupled with field data on pillar stability from the Mine. Excavations spans to prevent caving were determined by historical experience and field data on span stability from the Mine, coupled with numerical modeling. The minimum pillar size was determined to be 7.5m. The maximum pillar height was established at 2.5m. The maximum allowable excavation span was determined to be 8.5m. With these criteria, extraction ratios between 54 and 73% (measured in plan view) were determined to be appropriate for the protection zone.

May 1, 2001

By Kamran Esmaieli

This paper investigates the behavior of ore pass walls under impact loads caused by material transiting through an ore pass. In particular it considers the influence of foliation in the rock mass surrounding an ore pass as both a triggering and accentuating cause of degradation. Based on empirical observations in several underground mines a numerical experiment was designed to understand the influence of rock mass foliation on impact-induced damage on ore pass walls. The distinct element method, and in particular the Particle Flow Code (PFC2D) was used to simulate three different rock masses surrounding an ore pass. Each simulated rock mass has similar properties but was defined by distinct dominant foliation (70o, 80o, 90o) along the foot wall. The numerical experiments investigated different scenarios whereby the walls were loaded by a projected rock fragment striking the foliated walls at a constant impact angle and velocity. The damage inflicted by the projectile rock fragment, on the foliated rock mass, was quantified using the number of impact-induced micro-cracks initiated on the ore pass wall. The results of the numerical analysis indicated that the presence of foliation resulted in greater damage zones in the surrounding rock mass. In addition, the extent of impact-induced damage to the ore pass wall increased as the angle of interception between the ore pass wall and the rock mass foliations decreases. This is in agreement with qualitative field observations.

Jun 1, 2012

By O. C. Rojas, J. Sanhueza, J. C. Vargas

Empresa Nacional de Minería (ENAMI) is dedicated to the promotion of small and mid scale Chilean mining industry. Paipote, ENAMI Copper Smelter, processes a variety of mineral products as the result of this promotion. The mineral products characterize a wide variation of copper, iron, sulfur and precious metals content as well as the significant dispersion in the content of impurities, such as arsenic, antimony and bismuth. The Smelter Modernization Program, initiated in1997, introduced a series of technological and operational changes. The development of operational planning and control strategies was necessary to optimize the blending of a wide variety of concentrates and the control of metallurgical processes in order to ensure the stable operation, fulfillment of environmental regulations and the quality of produced copper anodes. A permanent optimization process carried out in the last decade led to the permanent increase of the smelting capacity and the production of anodes and sulfuric acid. Additionally, introduced improvements affected the smelter efficiency and metallurgical recovery, demonstrating the possibilities of the optimization of a small smelting facility reflected in good metallurgical and economic results. This paper presents the smelter evolution, introduced technological and process control changes as well as incorporated new reactors and equipment as a continuous process of optimization.

Jan 1, 2007

By D W. MacFadgen

THE operating advantages of the longwall retreating system of mining, as opposed to longwall advancing, have been well known for many years. Although retreat walls have been successfully worked in the past in some of the collieries of the Dominion Steel and Coal Corporation in the Sydney, Picton and Cumberland areas, the adoption of longwaIl retreating as the general sys-tem of mining has not been attractive in the Sydney field, due to the time and expenditures required to drive roadways to the boundary. In addition. difficulties in maintaining effective ventilation on the faces, especially under conditions of low barometer, have made the operators in the field hesitant to adopt this as the general system of mining. The development of a machine capable of rapid entry drivage has made possible the driving of the necessary road ways to the boundary at a moderate cost, completely changing the picture and making a retreat system more attractive.

Jan 1, 1961

By J. Warner, K. A. Hughes, P. E. R. Blanchard, J. Esslifie-Dughan, J. W. Reid

Tailings management plays an important role in reducing the environmental impact of Orano Canada’s uranium mining operations in Northern Saskatchewan. Uranium ores mined from Northern Saskatchewan are often associated with large amounts (10-20 wt%) of other harmful elements, such as arsenic and nickel. The JEB Tailings Management Facility (TMF) located at McClean Lake, Saskatchewan is designed to prevent potentially harmful water-soluble elements, particularly arsenic, from contaminating the surrounding environment by promoting the formation of water-insoluble minerals. It is therefore important to determine which arsenic-containing mineral species are present in the TMF and how they evolve over time. Researchers at the Canadian Light Source (Saskatoon, Saskatchewan) were successful in identifying the arsenic mineral species present in tailings samples collected from the TMF in 2013 using X-ray absorption near-edge structure (XANES) spectroscopy. XANES analysis verified that the majority of arsenic species in the TMF existed as amorphous and crystalline ferric arsenates with minor amounts of arsenite and arsenide species. Herein, XANES is again used to analyze a new set of tailings samples collected from the TMF in 2018, specifically focusing on the difference in the distribution of arsenic species in old and new tailings.

Jan 1, 2020

By J. Janeson

Wall control at the Pipe Open Pit is of primary importance in ensuring the long-term stability of the operation, while keeping costs to a minimum. Blasting techniques have been adapted to the variations in competence and structure of the wall rocks. A portion of the perimeter wall is being developed in incompetent peridotite . A recent change in pit slope design provides a wide safety berm on alternate benches. A support program which consists of pinning the crests of wide berms with vertical reinforced concrete dowels and horizontal bolting of walls shows evidence of increasing the stability of the pit walls. This paper describes the blasting and support techniques which are contributing to successful wall control in the Pipe operation.

Jan 1, 1979

By JOHN H. HUDSON

Ceramic clays of the Prairie Provinces range in age from Lower Cretaceous to Pleistocene and Recent. Two significant ceramic clay horizons are the Paleocene Willo wbunch Member of the Ravenscrag Formation in Southern Saskatchewan and the Upper Cretaceous Whitemud Formation, which is found in Saskatchewan and Alberta. The Willowbunch Member is worked at one locale in Saskatchewan; the Whitemud Formation is worked at several locales in Saskatchewan and Alberta. Bentonite operations are found at Morden in Manitoba, Rosalind and Onoway in Alberta, and Wilcox in Saskatchewan.

Jan 1, 1984