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By T. Feldmann, G. P. Demopoulos

The feasibility of chloride leaching processes depends on interfacing them with cost-effective HCl regeneration technologies. This paper summarizes the most important findings of research conducted in the past 3 years concerned with a novel process to regenerate high-strength HCl from concentrated CaCl2 solutions at temperatures below 100°C, via reaction of CaCl2 with H2SO4 resulting in the formation of calcium sulfate phases (gypsum, a-hemihydrate or anhydrite). From constant supersaturation semi-batch experiments in pure solution it was found that the crystal growth rate of hemihydrate, and hence the particle size, was influenced by the rate of reagent (Ca2+, SO4 2-) supply to the reactor. Additionally, growth studies of DH in presence of impurities (K+, Mg2+, Sr2+, Ba2+, Fe2+/3+, Al3+, La3+, Y3+, F- and PO4 3-) showed that specifically Sr2+ and PO4 3- are taken up during crystal growth. Furthermore, it was found that decreasing water activity (via different HCl/CaCl2 concentrations) and increasing temperature reduce the metastable life-time of DH and HH by increasing the phase transformation speed. The DH/HH transformation was identified to be dissolution-precipitation based, while HH to AH is a topochemical process. Finally, continuous experiments on bench scale are underway to confirm the feasibility of the process to obtain super-azeotropic strength HCl with up to 9 mol/L (~30wt.%) from 5 mol/L CaCl2 (~40wt.%) solution.

Jan 1, 2014

By T. T. Wang, T. H. Huang, S. S. Zhan

"Fractures with diverse features dominate the hydraulic behavior of fractured rocks and are one of the major subjects for hydrogeological characterization of a site. This study investigates curve patterns obtained by packed tests, and as well the influence of fracture features based on 59 sets of in situ packer tests with different fracture combinations and fracture features. The result shows that, in the example of Heshe site, neat and tidy fractures usually provide stable channel for water flow during testing, and the hydraulic properties of fractures infilled with breccia and mud may change during testing because of leaching and/or washed out of infilling breccia and mud. Different combinations of fractures with diverse features in packed test sections lead to different curve patterns for in situ hydrogeological tests. For groundwater flowing predominately through neat and tidy fractures, the pressure-discharge curve of modified Lugeon tests are usually linear curve pattern, and the pressure decrease while the discharge increase in pressure-discharge-time curves of single-hole double packer tests, which benefit statistically determining the transmissivity of dominant fracture sets. INTRODUCTIONFractures interlaced in rock masses are major channels for groundwater flow and generally account for the anisotropic and heterogeneous characteristics of permeability for fracture rocks. To describe reasonably the permeability of a fracture rock, the Discrete Fracture Network (DFN) approach and others with similar ideals have been developed. Many methodologies and associate equipment, for instance, the televiewer and the in situ hydrogeological test, have been proposed to investigate the spatial distribution and the transmissivity for different fracture sets, which are two main parameters necessary for the DFN or similar model simulation (Pearson & Money, 1977; Barker & Black, 1983; Hsieh et al., 1985; Bernard et al., 2006; Quinn et al., 2012). However, diverse outlooks for the pressure-discharge curves and the temporal pressure and associate temporal discharge curves often confuse the investigation results by significant deviations on derived permeability (Houlsby, 1976; Zlotnik, 1994; Royle, 2009; Camilo, 2010).Aiming on technical development for in situ hydrogeological tests and fracture investigation, an experimental well site with 10 wells has been established in Heshe in central Taiwan since 2011 (Wang et al., 2011; Song, 2012; Zhan et al., 2013). Extensive geological survey and well-hole scanning by a televiewer provide spatial distributions and outlooks of fractures in detail. Additionally, a series of Lugeon tests, double packer injection tests and pumping tests have been performed to investigate the permeability of fracture rocks, and dominate fracture sets as well. Based on the results obtained from the Heshe site, this study classifies the curve patterns of hydraulic packer tests. The features of fractures involved in packed sections for packer tests are then inspected in detail. Relationship between the curve patterns of hydraulic packer tests and associated features of corresponding fractures in rock are discussed and addressed accordingly."

Jan 1, 2015

By C. Liu

Zeta potentials and settling rates of an oil sands tailings sample taken from Syncrude Canada Ltd's Aurora Stacker Pilot Operation were studied. Two clay minerals, kaolinite and illite, were also studied since these are the major constituent minerals in the fine oil sands tailings. Process water, decanted water as well as distilled water were used. It was observed that the zeta potentials of the tailings solids showed maximum negative values in process water at pH 8-10, which coincides with the pH of commercial hot water bitumen extraction process. The settling rates of the tailings sample were very low, at 0.008 m/hr in decanted water and 0.04 m/hr in process water. The rates were increased to 1.0 m/hr in decanted water and 0.13 m/hr in process water at an addition of 50 g/t Ciba AF1235. Although the settling rate was higher the supernatant was cloudier in decanted water than in process water. Further increase in the dosages of Ciba AF1235 did not increase the settling rates in decanted water but gradually increased it in process water, reaching 0.46 m/hr at 100 g/t. The results indicated that lower concentrations of Ca2+ and Mg2 (in decanted water) benefited settling rates but did not benefit supernatant clarity. Test results also indicated that Ciba AF1235 caused selective flocculation of the tailings sample, since the top sediments had higher illite and lower quartz contents than the bottom sediments.

Jan 1, 2006

By J. Kolacz

"A new sensor based sorting system has been developed, providing a possibility for laboratory scale testing and further scale-up of the separation results to the industrial operation. The new system contains different sensors as: X-ray detectors, visible light cameras, NIR cameras, ultraviolet cameras and magnetic sensors, in the same sorting unit. The sorting unit allows advanced calibration options and fine-tuning of the installed sensors to achieve the best separation effect under controlled conditions. Finally, the processed material can be analysed and separated by the rejection mechanism, similarly to the industrial scale operation. At the same time, the process is carried out with limited amount of material allowing detailed statistical calculations for processed particles and all sensor types. The optimal settings and sensor types are specified for the industrial application.The paper describes the scale up of the results achieved for iron ore and coal, where the test work was first carried out using the new laboratory sorting system and where the industrial scale sorting system has been built, in the final stage. The industrial scale sorting results showed a very good correlation between the laboratory and full scale operation. Thanks to the detailed study carried out in the laboratory equipment, the settings of the sensors in the full scale operation provided much better separation efficiency. It was especially important to provide proper setting for the X-ray sensor data calculations, which can be very critical for achieving the best results. During the industrial scale sorting of coal, the input material had 40-55% rock particles as the direct source of ash in the coal stream. The optimal laboratory unit settings and transferring these settings to the industrial sorter, provided 98.8% efficiency for removing rock particles with only few % losses of coal."

Jan 1, 2016

By H. C. Cooke

Those who have followed the geological developments in connection with the copper deposits of Quebec will recall that on many properties the sulphide bodies occur as replacements of fault breccias or tuff breccias, and exhibit a pronounced distaste for the more massive lavas. At the same time the rocks around the ore-bodies are profundly altered, first by addition of silica and sericite, later by conversion of these minerals into chlorite. It has been known for some years that at the Amulet and Waite-Ackerman Montgomery mines these conditions do not prevail. At both mines the ore-bodies are replacements of massive lavas, and at the Amulet they are associated with a very peculiar rock christened ?spotted dog', or 'dalmatianite'. Accordingly, when in 1929 the writer had the opportunity to make a further examination of these properties, two problems presented themselves for solution. The first was to determine, if possible, the conditions under which massive lava, rather than breccia, is replaced by the sulphide masses; the second, to find out the exact nature of dalmatianite and its relations to the sulphide bodies. The first of these problems is believed to have been solved; the second has been found very complex, and will require further work before it is satisfactorily settled.

Jan 1, 1930

By J. Sliwinski, H. Kikutani, J. Atwood, D. Larimer, J. Pyecha

"The Pogo mine start-up milling targets of 2005 are vastly different than the targets of today. Improvements have been driven by unintentional design oversight, continual circuit optimization or optimization due to changing mineralogy. The more significant process improvements to date have occurred in the gravity, flotation and leach/CIP unit operations. Details of the significant improvements are presented along with the impacts to the process.INTRODUCTION Deposit Overview Pogo mine is located along the Goodpaster River, southeast of Fairbanks, Alaska. This deposit sits in the center of the Tintina Gold Province (Figure 1), a region of similar Intrusion Related Gold deposits in Interior Alaska, the Yukon and British Columbia Canada (McCoy et al., 1997). The Pogo deposit is hosted in a rock sequence of amphibolite-grade gneisses intruded by mid-Cretaceous granitic plutons and dikes, which in turn, were cut by and host the auriferous quartz veins of the Pogo deposit.The Pogo deposit is comprised of three distinct zones of auriferous quartz veins spatially adjacent to each other. These are the Liese Zone, North Zone, and the East Deep Zone. The Liese Zone consists of three stacked, massive quartz veins, designated the L1, L2, and L3. Vein thickness averages 3.0 m, with variations from 0.3–18 m thick. The North Zone mineralization is comprised of four veins with more consistent thickness, between 1 and 1.5 m. The East Deep deposit lies northeast of the Liese Zone ore body. It is separated by a post mineralization, quartz diorite pluton. The East Deep Zone is comprised of two stacked massive quartz veins with similar orientation as the Liese Zone."

Jan 1, 2017

By S. Beskri, N. Geoffroy

When metallurgical plants are designed, a lot of consideration is almost always given to material selection and possible damage mechanisms. Materials engineers are generally involved and will strive to select optimal alloys or refractories for the design conditions. Once in operation however, things often change. Equipment is overstressed to increase production, corrosive leaks are not always promptly addressed, proper welding procedures are disregarded, etc. This paper describes various cases from the mining and metals industry where serious mishaps, associated consequences, and costs could have been avoided if simple and proactive steps had been taken. It also presents a strategy, based on safety reviews, to help predict and prevent damage to critical pieces of equipment.

Jan 1, 2015

By J. A. Allan

The utilization of natural deposits of salt is one of the oldest industries in Alberta. In 1820, Sir James Richardson visited Salt river, and in the same year D. W. Harmon states chat "clown Slave river, there are several places, where almost any quantity of excellent dean white salt may be taken, with as much ease as sand along the seashore. From these places the greater part of the northwest is supplied with this valuable article". This reference is to the salt chat occurs around springs on Salt river at the northern boundary of the Province. This and other occurrences will be described later in this paper. It is not on account of the development of salt and gypsum in Alberta chat this paper has been prepared, but rather to draw attention to the widespread distribution of salt-bearing and gypsum-bearing rocks, and to the stratigraphic importance of these rocks . The origin of the deposits of salt, gypsum, anhydrite, and dolomite is discussed, and the economic significance of these minerals is considered. There is no salt production reported from Alberta in 1928.

Jan 1, 1929

By P. Babak, E. Insalaco, O. Babak, P. Henriquel

"Detection of outliers is an important primary step in geomodelling. Geological datasets often contain errors due to problems such as measurement device limitations and recording glitches. In this paper, a robust Mahalanobis distance–based approach is successfully applied to particle size distributions of the Joslyn lease, an oil sands development site near Fort McMurray, Alberta, Canada. Automatic outlier detection and geological review were combined. Outliers from the Mahalanobis distance approach were compared with their respective core photographs to determine if laboratory measurements and facies classification were correct. A checking procedure for laboratory technicians is proposed.RÉSUMÉ La détection des valeurs aberrantes constitue une étape primaire importante de la modélisation géologique. Les ensembles de données géologiques contiennent souvent des erreurs en raison de problèmes tels que les limitations des instruments de mesure et des pépins d’enregistrement. Dans le présent article, une méthode robuste basée sur la distance de Mahalanobis a été mise en oeuvre avec succès aux granulométries du bail minier Joslyn, un site de sables bitumineux en développement à proximité de Fort McMurray, Alberta, Canada. La détection automatique des valeurs aberrantes a été combinée à une étude géologique. Les valeurs aberrantes de la méthode de la distance de Manalanobis ont été comparées avec leurs photographies respectives de carottes de forage afin de déterminer si les mesures en laboratoire et la classification des faciès étaient correctes. Une procédure de vérification pour les techniciens de laboratoire est proposée."

Jan 1, 2015

By J. U. MacEwan

Introduction The equilibrium between copper, zinc, and chlorine may be considered as the simultaneous equilibrium of the two separate chemical reactions of formation of the stable chlorides of copper and zinc at the temperature of the reaction i.e., l440°K. (1,167°C., 2,133°?F.)§ [Zn(g) +Ciz(g) ZnCl2z(g). ... (1) ] [2Cu(l)+Cbi'g) Cu2Cl2(l 1 ....... (21 ] Subtracting, [Zn(g) +Cu2(Clz(l i ZnClz(g) +2Cu!l) ... . (3) ] If this reaction is carried out with a copper-zinc alloy at some constant temperature above the melting point of brass, and at a total pressure of one atmosphere, the equilibrium concentrations obtained will depend on the free energy decrease .of the reaction as written in (3) and on the activities of the various components in. the reaction mixture. If the equilibrium is examined from the point of view of the phase rule, it is a three-component system, and if it exists in two phases (liquid and gas) it will have three degrees of freedom. If the restrictions of constant temperature and pressure are imposed, the degrees of freedom are reduced to one. This means that, in a two-phase system under these conditions, each different alloy phase will be associated with a gas phase of constant composition.

Jan 1, 1951

Situation Brands & Employment Value Propositions of mining sector firms are perceived negatively Competitive labour market is generally not aware of the diversity of mining careers Jobs requiring unique skills & experiences are no filled Traditional means of generating awareness to attract candidates is not aligned with how youth (for example) uses technology throughout the recruitment process Gobal economic downturn

May 1, 2009

By J. Dennett, M. Faris, M. Antonio, M. Collins, N. Tuffrey, R. Ellenwood, V. Reddy

"In January 2012, AngloGold Ashanti Córrego do Sítio Mineração, with assistance from Sherritt International Corporation, commissioned a new autoclave for pressure oxidation of refractory gold concentrate at the Córrego do Sítio operation in Brazil. Start-up of the plant occurred in a few weeks and enhanced gold recovery was realized almost immediately, with 94% gold extraction achieved in carbon in leach (CIL), compared to less than 70% without pressure oxidation. This paper describes start-up and commissioning of the plant and provides an overview of plant performance over the last five years.INTRODUCTION In 2008, AngloGold Ashanti purchased the former São Bento property from Eldorado Gold, which, along with AngloGold Ashanti’s existing Córrego do Sítio mine, was renamed AngloGold Ashanti Córrego do Sítio Mineração (AGA Mineração). Later that year, the Sherritt Technologies division of Sherritt International Corporation (Sherritt) was contacted to begin batch and continuous pilot plant tests to determine the amenability of the AGA Mineração refractory gold concentrates to the pressure oxidation process. Based on the results of the batch and pilot plant tests, AGA Mineração requested basic and detailed engineering studies to be conducted by Sherritt, eventually leading to commissioning of the plant in January 2012. AGA Mineração’s plant is located in southeastern Brazil in the state of Minas Gerais, near the city of Belo Horizonte. AGA Mineração`s Phase 1 mine plan covers three sites in the Laranjeiras, Carvoaria Velha and Cachorro Bravo ore bodies, and is designed to process 60,000 tonnes of refractory gold concentrate per year to produce 140,000 ounces of gold per year with an 11 year life of mine (AngloGold Annual Financial Statements, 2010). Recovery of gold at AGA Mineração is based on Sherritt`s pressure oxidation technology for refractory gold concentrates (Berezowsky et al., 1991; Collins et al., 2011a; Collins et al., 2011b). This process had previously been applied to the recovery of gold at the São Bento site (Carvalho et al., 1988; de Silva et al., 1989), in a plant that was operational between 1986 and 2007 (Silva et al., 2004)."

Jan 1, 2017

By A. L. Irwin

THE problem of compensation for labour is probably the oldest and most complicated one in history. The wage that a man receives is possibly the most concrete thing he gets out of his job and, rightly or wrongly, is generally considered by him to be the most important item in connection with his daily work. How today workers in an equitable way has been the study of industrialists for many years, and a great number of ideas have been tried out in an effort to arrive at a reasonable solution of the question. The idea of establishing a measuring stick for various types of work has intrigued industrial management for a long time and, after considerable study, the principle of Job Evaluation has taken form unti1, at the present time, it is becoming increasingly useful to industry at large. Job evaluation is a plan which is used to determine the relative worth of occupations by means of arbitrary measuring scales. These scales are developed for individual industries and are generally 'tailor made' for each particular case. There are as yet no absolute methods of measuring the work done by human beings and, as a result, one has to depend on comparative values to arrive at conclusions. However, job evaluation has provided us with a basis of negotiation for wage rates which is more satisfactory than mere guess work or persona! opinion. It supplies a common ground for discussion which is understandable by all taking part and ensures that thinking with regard to wage setting is carried out along standard lines.

Jan 1, 1943

By Thomas H. Heine

"The Rabbit Lake uranium deposit is located at 58° 11’00”N.. 103°42'36""W., close to the west side of Wollaston Lake, and approximately 800 km north of Saskatoon. The orebody is hosted by Aphebian Wollaston Group rocks, initially deposited as a series of shallow-water marine sediments consisting, in part, of carbonates and possible saliferous petites. Metamorphism during the Hudsonian Orogeny, peaking at about 1850 Ma, recrystallized the sediments to upper amphibolite grade paragneisses. This was accompanied by partial anatexis. The waning stages of Hudsonian orogenesis appear to be marked by minor granitic intrusive activity.The post-Hudsonian period was marked by a long interval of physical and chemical erosion, resulting in the unroofing of the Wollaston metamorphic complex. The entire region underwent extensive lateritic weathering under tropical to subtropical conditions. Carbonates were especially vulnerable and, in the Rabbit Lake area, suffered extensive solutioning with accompanying formation of collapse breccias. Old zones of weakness also underwent periodic reactivation.It was during this period that uranium was leached from the surrounding meta-sediments by oxidizing meteoric waters, and transported into the karsted and fractured rocks of the Rabbit Lake doline.Athabasca Group sediments eventually covered the deposit, their diagenesis taking place at about 200 °C and 900 bars. This allowed the partial to complete recrystallization of the initial mineralization, resulting in a minimum age of 1281 ± 11 Major ""first""-generation pitchblende. Periodic fault/fracture reactivation modified the hydrologic regime within the deposit, resulting in episodic mobilization and recrystallization of pitchblende and other uraniferous species. This is clearly shown in the open pit at the present time: uranium is being mobilized and recrystallized on damp pit walls as bayleyite and liebigite due to the modification of the hydrologic system by mining activities.The uranium mineralization occurs mainly as fracture fillings, coatings, and impregnations within breccia zones and intensely altered metasediments. Lesser mineralization is intimately associated with phyllosilicates which form the matrix of a carbonate-col/apse mega-breccia. The primary ore mineral is pitchblende, consisting of five generations, and from which a large suite of secondary uraniferous minerals have formed. On a gross scale the metal content of this deposit appears to be simple, consisting almost exclusively of U, but minor Ni, As, Cu, Se, Fe and Co are also present. The eastern limit of the mineralization is defined by a vertically-dipping microgranite dyke - breccia complex, containing high-grade uranium values. The orebody is truncated to the west and at depth by the Rabbit Lake reverse fault. Minor mineralization occurs as fracture fillings in unaltered plagioclasite in the footwall of the ore body. Precipitation of uranium from solution could have taken place by a number of processes. A mobile reductant (methane, carbon dioxide, etc.) may have been generated from graphite present in some of the host rocks of the orebody. Sulphides are also a common accessory and may have aided in the formation of a reducing environment. Phyllosilicates may have acted as adsorbants for uranium, allowing for its fixation. This metal has also been incorporated into the phyllosilicates themselves."

Jan 1, 1986

By B. Lewis

Paper did not make deadline for printing

Jan 1, 1982

By M. B. Greyver

The results of laboratory tests on iron precipitation from non-decopperized nickel anolyte are discussed. The parameters (pH, oxygen consumption and stirring speed) for iron precipitation from the anolyte, using the oxygen in the air, were determined. In the experiments conducted under optimized conditions, the residual concentration of iron in the anolyte after precipitation was 0.7-2.7 mg/L, and the copper and nickel losses to the solid phase were 0.05-0.07% and 0.05-0.16%, respectively. The filtration ability of the iron slurry obtained was 2 to 5 times higher as compared to that after chlorine oxidation and oxyhydrolysis. The leaching of the non-ferrous metals from the iron cake made using the separate nickel anolyte purification process was possible by dissolution in sulphuric acid. It was established that after cobalt precipitation from the copper- and iron-depleted anolyte, the precipitates obtained had lower ratios of Fe:Co and Ni:Co.

Jan 1, 2006

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 J. C. Hawkins

Determining moisture content and rate of flow of a solid product make measurement and control of dryers unusually difficult. This paper de-scribes a method of accomplishing this with readily made air-temperature measurements. The system can cope with changes in feed moisture and feed rate. It does not measure solids temperature. The system's application to several typical rotary dryers is described, and control schemes using feedforward techniques are explained.

Jan 1, 1971

By L. Magne, M. Maldonado, R. Varela

Real-time optimization of flotation circuits demands for accurate and reliable measurements to support the decision making process. The collection zone gas holdup is an important variable in this context as integrates the effect of machine and chemical factors on the bubble size and velocity distributions. It has been demonstrated that gas holdup not only correlates with bubble surface area flux, which defines the particle collection rate and recovery in the collection zone, but also with water overflow, a variable which has been related to the froth zone recovery. Therefore, on-line gas holdup measurements provide a reliable alternative to judge efforts leading to the optimization of flotation cells and columns. Estimation of gas holdup in flotation from electrical conductivity measurements has been proposed and extensively used in lab and industrial installations. The approach is based on the application of Maxwell's model, which relates the concentration of a dispersed phase in a continuous medium to measurements of the conductivity of the liquid medium and of the mineral pulp with and without air bubbles included. These measurements require a conductivity cell which covers a representative volume of the flotation cell, and creates a homogeneous electric field throughout this volume that ideally is not affected by the conductivity of the medium. The development of such a cell in the limiting space and geometry of a laboratory flotation cell has been problematic, but a multi-electrode arrangement offers a promising alternative. Electrodes were installed in the flotation cell of a Denver unit; the results of preliminary testing are discussed with a focus on its performance in the measurement of two- and three-phase dispersion conductivity.

Jan 1, 2015

By L. Callele, C. DiGiovanni, L. Li, R. Driver

"Hot-dip galvanizing is a common procedure used to protect structural steels from corrosive environments. However, in a construction project involving welded structural steel platforms by a Canadian steel structures company, numerous connections were found with large cracks in the welded corner joints and T-joints after galvanizing. Historically, in other similar projects by the same industry partner, cracking did not occur making this an unforeseen and new phenomenon. The project explored the mechanical properties of the base material, the thermal stresses induced by the hot-dip galvanizing, and the fracture surface of the cracks. A key feature to note, the fracture surface showed intergranular cracking with no plastic deformation. Lab testing showed the base material exhibited intergranular brittle behavior when heated and fractured at the galvanizing temperature. The transition to a brittle fracture mode is due to temper embrittlement and the segregation of elements in the grain boundaries.INTRODUCTION Galvanization is a common practice for protecting steel structures from the corrosive environment. Hot-dip galvanizing is the most common approach to bonding the zinc layer to the steel, and it is highly cost effective. In the case of welded structures, it is common to do the hot-dip galvanizing process after welding. This is so the protective layer can be applied to the structure as a whole and over the welds. In a recent construction project carried out in industry, a steel frame platform structure measuring approximately 3 m x 7 m was galvanized after welding fabrication. The structure was built of CSA G40.21 350W and CSA G40.20/G40.21 300W plain carbon steels and welded using a metal core arc welding process for the flanges and a flux core arc welding process for the webs of the beams. Due to their size, the platforms underwent a double-dip galvanizing process meaning half of the structures were submerged in the molten zinc path while the other half was exposed to the ambient air. This was repeated for the remaining side. Shortly after the galvanizing process was completed, numerous large cracks were found in the welded joints. Given there was no history of weld cracks after galvanizing in previous similar frames that were double dipped, this failure posed a new and curious problem."

Jan 1, 2017