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By Binxu Zhaug, Mark Jolly, Xiaojun Dai

"In conventional investment casting process of aluminium alloys for the application of the aerospace industry, to assure the quality of the final casting, usually the foundry uses large runner system which results in low yield, high energy consumption and high GHGs emission. In one case of this investigation, the yield is between 5 ~ 10% which means that the current casting process wastes large amount of energy and generates lots of scraps. By applying a new casting method, the bulky runner system and the melting/holding time are significantly reduced, the quality of the casting is improved, and in the meantime the related energy consumption and GHGs emission are significantly decreased. In the investigation, the energy efficiencies and GHGs emission between the current and traditional processes are calculated and compared.1. IntroductionAs one of the conventional casting process, Investment Casting Process (ICP) and its applications can be traced to thousand years ago [l]. In current casting industry, ICP still plays an important role in the production of small and precious castings with high quality requirements in automobile and aerospace industries. Both casting quality and manufacturing costs which mainly consist of energy costs have crucial effects on the competitiveness of castings in the market. In the production of aluminium alloy castings using ICP, the energy cost and energy efficiency of a casting facility depend mainly on the efficiency of its melting and heat treating performance. In association with the two performances, more than 60 % of the total process energy costs are symbolised in a typical casting facility [2]. Additionally, in conventional ICP of aluminium alloys for the application of the aerospace, to assure the quality of the final casting, typically the foundry uses huge runner system including big risers/feeders which cause low yield, creates lots of scraps and generates high energy consumption. Consequently, there are huge opportunities for casting industry to choose the best practices for potential energy saving. Furthermore, the reasons such as the stringent limitation of environmental legislation in Europe and the pressure of the rising energy price force the casting industry to reduce the energy consumption and greenhouse gases (GHGs) em1ss10n."

Jan 1, 2012

By N. Hoffman

Accurate, repeatable density measurements of a coal-magnetite-water slurry are difficult to achieve using a nuclear density gauge. Changes in the coal-to-magnetite solids ratio cause fluctuations in the readings of nuclear gauges. To investigate this problem the Electric Power Research Institute's Coal Cleaning Test Facility compared the performance of a nuclear density gauge on a coal-magnetite-water slurry with the performance of a differential pressure gauge modified with a new pressure sensor. A second aim of these preliminary tests was to determine if the differential pressure gauge is also sensitive to the type of solids in the slurry. This paper explains current slurry density measurement practices, describes the nuclear and differential pressure gauges used in the CCTF tests, and presents test methods and results.

Jan 1, 1986

By V. K. Reddy Kallam, NEHA PANDEY, Sunil Kumar Tripathy, ARIJIT BISWAS

The study investigates SO2 leaching of low-grade ferruginous manganese ores to selectively recover manganese as MnSO4 and produce battery-grade electrolytic manganese dioxide (EMD). The effects of leaching parameters (duration, temperature, SO2 flow rate) on Mn recovery were studied. Under optimum conditions, 97.9% Mn recovery was achieved. The MnSO4 leach liquor was purified and used for electrowinning EMD with 88.01% purity and battery-active γ structure.

Apr 20, 2022

By C. O. Aksoy, H. Kose, K. Ozfirat, T. Malli, A. Gonen, S. Gurgen

In selecting mobile mining equipment, factors including availability, useful economic life, maintenance and operating costs, and spare parts availability are considered. Given these factors, trucks and shovels with different capacities are selected. Optimizing equipment for pit and hillside quarry cases, where 8% and 10% ramps are commonly in use, were examined; the effect of other mining activities such as drilling and blasting on unit cost were considered. In principle, 20 m to 25 m high benches should be economical for downhill haulage, and 7 m to 10 m low benches economical for uphill haulage. However, practice of both mining styles favours 10 m to 15 m bench heights. Hence, the analysis here was carried out with the field experience bench height range. In the study, a truck-shovel optimization was based on the movement of 5 to 20 million cubic metres (in 2.5 million cubic metre increments) of overburden stripping at the Eynez open pit mine in the Soma region of Turkey. The outcome showed that low-capacity shovels were unfavourable due to high production expectations. High-capacity shovels were also unfavourable due to health and safety issues causing high instances of impact vibration on trucks during the loading cycle and a decrease in foreseeable unit lifetimes. The number of shovel passes required to load a truck ranged from three to six. Trucks with high-capacity bodies were deemed uneconomical due to high investment and operating costs.

Jan 1, 2005

By D. Ofstie, B. Kargutkar

BIM, or Building Information Modeling, is transforming the way metallurgical facilities are built, operated and maintained. BIM provides a digital representation of the facility, complete with all physical and functional characteristics - enabling collaborative planning, concurrent design, construction simulation, sustainable operations and predictive maintenance through a connected information model. Building on experience gained in other industries, Hatch is aggressively applying the BIM process to the mining & minerals processing industry to address inefficiencies inherent in traditional document-based information management. Intelligent 3D models support real-time quantity forecasting and cost trending by commodity type and construction work package. By linking procurement and schedule data, material availability and constructability reviews are visualized to verify construction critical path, ensure work front safety and minimize craft downtime. The BIM digital information model connects engineering, construction, commissioning and vendor data, aiding timely asset-centric handover to plant operating and maintenance systems.

Jan 1, 2015

By Brian Gar Wingfield

Bulk explosive systems have developed from the infancy stages in the early sixties to a sophisticated process of the nineties. With ever changing bulk explosives technology, bulk delivery and loading systems needed to keep pace. Efficiency, as compared with packaged loading, was the keyword allowing faster loading of trucks and shots. Efficiency was also improved by the explosives coupling factor that bulk loading permitted.

Jan 1, 1991

By J. D. Miller

Low-level radioactive contaminated soils (10-500 pci/gm) created by defense-related activities at certain superfund sites, such as Nevada Test Site (NTS), is a current environmental concern. Many of these contaminated sites may require appropriate cleanup and restoration, which could cost billions of dollars and put tremendous pressure on our limited financial resources. Therefore, the development of a selective flotation process to separate such radionuclides from contaminated soils should be considered. In this study, both a pure depleted UO2 sample and three synthetic UO2/soil mixtures were used to evaluate surface chemistry features and to examine the possibility for the flotation of fine UO2 particles from selected soils. It was intended that this model system would be a reasonable representation of contaminated soils such as those found at the Nevada Test Site which are reported to be contaminated by PuO2 fallout. The effect of reagent schedule, particle size distribution, and surface charge are discussed with respect to the flotation separation of the UO2/soil mixtures. It was found that both commercial fatty acids and reagent grade sodium oleate are effective collectors for UO2 flotation provided the pH is adjusted to the range of pH 8-9. The bench-scale flotation results successfully demonstrated that froth flotation technology can be used to remove UO2 from such model contaminated soils with appropriate flotation chemistry conditions which depend on the soil characteristics and other pretreatment procedures. In the best case, 90.2% of the UO2 was removed from a UO2/NTS soil mixture (119 ppm UO2) and the soil reduced in UO2 contamination from 119 ppm to 17 ppm in a single stage bench flotation. The impact of clay slimes present in the soil is revealed by the results which show that, for example, for a deslimed soil (28x400 mesh and 100 mg UO2/kg soil) 85¬90% UO2 recovery can be obtained with a reduction in contamination to 4.6 mg U02/kg soil.

Jan 1, 1995

By Ed L. Schrader

Kaolin of the Georgia-south Carolina "Clay Belt" are used in a wide variety of filler and extender applications. Sane applications specifically require the performance enhancement delivered by incorporating kaolin into the product formulations. Other applications are less specific in requirements for an inert mineral filler. In order to be a feasible candidate for filling and extending, a mineral or mineral product must be generally inert (except where specific interaction with the filled medium is desired), inexpensive, easily handled and transported in a variety of forms, accessible to a broad segment of the desired market, and must exist in sufficiently large ore reserves as to assure production for many years. Of course, more precise requirements are necessary in specific applications of a prospective filler material.

Jan 1, 1985

By J Player, R de Vries, J F. Carswell, R Hassell

"The feasibility of Dugald River mine was highly sensitive to mining and geotechnical design assumptions, particularly stope dilution and strike length. Following the start of initial mine development in 2012 the project was suspended in 2013 due to concerns over the complex ground conditions and resulting dilution, stope sizes and general mineability. A technical risk mitigation program was undertaken with a key aim to increase the level of confidence in predicting stope dilution.A stope sizing and dilution model was developed that provided a range of stope sizes based on geotechnical conditions and acceptable dilution. The original feasibility used a standard stope size of 25 m height by 25 m span. The new model was used as the foundation for the subsequent updated development plan for Dugald River that reduced much of the previous technical risk through greater confidence in the geotechnical and mining parameters.Several methods to predict stope hanging wall dilution and appropriate stope size have been used at Dugald River that relied on the modified stability graph method. Improvements to the method were identified as more rock mass and mining data became available through the completion of a trial stoping program, increased underground development and a large geotechnical core logging campaign. These improvements not only focused on the technical aspects of the model, but also on creating an easy to use and sustainable process that could be used at multiple stages of mine planning from life-of-mine (LOM) through to final stope design.Several of the main improvements are: understanding stope failure mechanisms and collecting only geological information that is most relevant detailed modelling restricted to the rock mass that could be expected to influence stope behaviour accounting for different stope failure mechanisms with the stability chart method assigning a geotechnical confidence factor to the data making it useful as a mine planning tool with integration into the mine planning process using performance of completed stopes to update and calibrate the model.The model provides recommended hydraulic radius and associated dilution estimates across the ore body. Providing the hydraulic radius allows planning engineers the option to consider single, double and triple lift stoping options suitable to mine scheduling. While the model has been calibrated for conditions at Dugald River the process used to create the model is not site specific and is applicable to other steeply dipping tabular orebodies.CITATION:Hassell, R, de Vries, R, Player, J and Carswell, J F, 2017. Improving the prediction of stope hanging wall dilution – a critical factor to the success of Dugald River, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 71–78 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 16, 2017

By St. Mergentime, K. Zeidler, V. Gall

2001, the New Jersey Transit Authority commissioned the JV Merco-Obayashi with the rehabilitation contract of the approximately 130-year-old, 4,200 ft long, partially brick- lined Bergen North Tunnel. The contract entailed the tunnel enlargement, shotcrete and rock dowels initial support according to the NATM, a waterproofing system, tunnel drainage and a cast-in-place concrete lining. The rock conditions encountered required design adaptations and significant modifications of the initial tunnel support. Flexibility, skill and extensive experience on the Authority’s and Contractor’s side finally lead to a success. This paper describes the operations and design modifications carried out.

Jan 1, 2003

By David E. Van Dillen

The computer program described in this user's guide provides for the static, three-dimensional, linear and nonlinear analysis of structural and geological systems by the finite element method. The guide describes the capabilities and general features of the program and shows how input is prepared. A number of recent advances in finite element theory and computer technology are incorporated in the program. Nonlinear material properties are provided for, including isotropic, anisotropic, and time-dependent material properties, gravity loading, simulation of a sequence of excavation or construction, and a slip or joint element. The finite elements include beam, rod, axisymmetric and plane quadrilateral, hexahedron, thick shell, axisymmetric and plane joint, and a three-dimensional joint. The program also has an automatic mesh generator to minimize user input preparation for continuum finite element meshes.

Jan 1, 1981

By Donka H. Andreeva

Gold catalysts based on different supports, titania, zirconia, ceria and mesoporous titania and zirconia, nonpromoted and promoted by vanadia in the reaction of complete benzene oxidation have been studied. XRD, HRTEM, TPR, Raman and ESR spectroscopy were applied for the characterization of the catalysts. The influence of gold on the reduction behavior, state and structure of vanadia on the surface was studied, as well as the role of supports nature on the properties and catalytic activity. A strong synergistic effect between gold and vanadia was observed for the all studied catalysts with an exception of the catalysts supported on mesoporous zirconia. In the last case the catalysts containing gold and gold-vanadia exhibit high and equal catalytic activity. The catalysts on ceria show highest and stable catalytic activity in the studied reaction among the all studied catalysts.

Oct 1, 2003

By Jurij Karlovšek, Marko Žibert, Scott Keniston

"SUMMARY The importance of information management was recognised in surface construction industry decades ago, and has increasingly being recognised through formal process and laws. Around the world, these laws and codes of practice are currently being drafted and enacted, to reflect the development of software tools and corresponding increasing adoption by industry. This paper deals with specifics of implementing information modelling in tunnelling business utilising BIM (Building Information Modelling) technology developed for buildings as well as similar technology developed for mining industry. Although BIM is recognized initially as a 3D digital representation of physical and functional characteristics of a facility, the real benefits come when complex capability through construction sequencing and even detailed programming (4D) and cost capabilities (5D) are included. INFORMATION MODELLING The Architecture, Engineering and Construction (AEC) industry requires the production of design and construction information, which involves the input from several teams. The tasks allocated to each team need to be carried out in a particular order and coordinated in order to benefit all those involved and the project itself; this is known as “collaborative working”. To ensure the quality, and guarantee that information can be used without change or interpretation, working processes and standards needs to be agreed upon or else it will hinder collaboration and have a negative impact on project delivery. Case studies show that the additional capital delivery costs due to uncoordinated, inaccurate and ambiguous information amounts to 20-25%. The solution to overcome these problems and improve collaborative working in a project is the adoption of BIM. It is a modern approach to the design, documentation, delivery, and life cycle management through the use of project information databases coupled with object-based parametric modelling. BIM requires traditional practices shifting from simple drafting to using 3D native models for building design environment. Additionally, it requires that models are equipped with information that has been traditionally decoupled in a text or other kinds of documents. The goal is not in creating a 3D graphic representation of design intent; rather, it is a comprehensive information management tool based on the simulation of design and construction build around a central repository."

Jan 1, 2016

By D. Holz

In this work we present a novel level set-based model for the real-time simulation of soil deformations. A level set defined by a signed distance function and sampled in a regular 3D grid represents and tracks the soil volume under deformation. Moving away from classical 2.5D heightfield representations of soil to a full 3D volume representation allows for improved tracking of cutting tool operations and the simulation of near-vertical or vertical soil faces. The proposed level set representation furthermore provides a versatile mathematical platform for modeling additional effects such as soil slip, and does not suffer from the sampling limitations of commonly used heightfields. Cutting forces applied to the tool are simulated via a formulation based on the Fundamental Equation of Earthmoving, modified to support inclined soil surfaces and transient states of tool motion. Discretisation of this 2D cutting force model with respect to the tool surface allows capturing the effects of irregular 3D terrain shapes on blades and buckets. The surcharge created during cutting operations is tracked in the form of particles and included in the soil failure force computation. We make use of an adaptive, hybrid level set-based and particle-based soil deformation scheme, which allows the soil deformation to be simulated in real-time.

Aug 1, 2013

By E. M. Timoshenko, A. V. Tarasov

The results of laboratory, bench-scale and semi-commercial investigations of a method for adding surfactant (technical-grade lignosulphonate) to the process of pressure leaching of nickel-containing pyrrhotite concentrates have been discussed. Lt has been demonstrated that feeding of technical-grade lignosulphonate distributed along the length of an autoclave ensures a reduction in its requirement by a factor of 1.5 to 2 as compared with single-point feeding; it also results in a decrease by 5% in the unit requirement of metallized iron-bearing precipitator in the process of non-ferrous metals precipitation and reduces by 0.05 to 0.1% (abs.) the nickel and copper contents in the tailings of the given process. Technical solutions have been proposed for commercial introduction of the process.

Jan 1, 2004

By D. J. M. Farnsworth

Since the 1.940's, the bulk of the ore production from the Sullivan Mine has come from pillars. These pillars, located from 100 to 2000 feet below surface, have been subjected to considerable ground pressure. Mining techniques were adopted to minimize the problems of deteriorating ground conditions. These techniques included an orderly sequential blasting of pillars along a retreat front, stage blasting of tall pillars in horizontal slices and utilization of broken pillars as "buffers". The latter two techniques involved leaving substantial tonnages of broken ore in place for as long as 4 years. Rapid oxidation of metal sulphides, with attendant heat and noxious gas generation, had occurred in a few very localized areas of the mine associated with a major water course. However, in a very short period starting in 1972, sulphide fires spread to several of the large blocks of broken ore that had been left inactive for lengthy periods. There proved to be no feasible method of extinguishing these fires, except by complete removal of the burning ore. The attendant problems of handling large tonnages of burning ore have had considerable negative impact on the mine operation. The chemical reactions involved in these sulphide fires have been studied by the mine staff to determine the conditions necessary for' initiation and propagation of the tires. Techniques to safely and efficiently handle hot ore have been implemented and refined. Lastly, and most important, mining methods at the Sullivan Mine have been revised to ensure that additional fires do not occur.

Jan 1, 1977

By E. J. Walls, W. C. Joughin

"In selecting a suitable method to sink a vertical shaft for underground access, a number of constraints influence the ultimate decision of where and how to develop the shaft, not least among these being safety, development and construction time, and cost. Two additional considerations stand out: these being geotechnical conditions and technology, the latter taking into account existing underground access. Assuming a project for which an existing underground excavation is available, it is tempting to build a shaft sinking project from the outset based on the raiseboring method, which has the potential to be the safest, fastest, and least expensive method provided that geotechnical conditions permit.And therein lies the rub: regardless of project time or cost constraints, when it comes to raiseboring a long (say, greater than 500 m), large diameter (greater than 4.5 m) shaft, the rock mass conditions ultimately dictate what method of shaft sinking will be feasible. Over the course of several studies for a particular project, several geotechnical analyses were carried out specifically for the purpose of developing a shaft by raiseboring. Risk analysis and experience showed that where the rock mass conditions indicated an unacceptably high risk potential, an alternative method needed to be considered, even if this meant increasing both the time and financial requirements.In this paper we present an overview of geotechnical investigation practices for shaft sinking. Decisionmaking thresholds for raiseboring or other methods of shaft sinking are discussed, including probabilities of failure, empirical rock mass classification, basic wedge failure, and back-analysis of a failed case. The design of appropriate support, and analysis of relative safety benefits for various shaft sinking methods, falls outside the scope of this work, and will be presented in a separate paper.IntroductionThe potential for rock mass failure during shaft development and construction affects whether a project is completed safely, on time and on budget. During the course of several studies to establish ventilation shafts for an underground expansion project, geotechnical analyses of rock mass stability and failure potential were carried out. The investigations were guided by the method of McCracken and Stacey (1989) together with insights from Peck and associates (Peck, 2000; Peck and Lee, 2007, 2008; Peck, Coombes, and Lee, 2011)."

Apr 1, 2019

By R. E. Campbell

Uranium metal of improved purity was prepared by electrorefining commercial magnesium-reduced uranium in a molten sodium chloride-uranium trichloride electrolyte. The best operating conditions for the preparation of refined metal were established as follows: an electrolyte containing 8.7 to 13.3 weight-percent uranium; initial cathode current densities from 300 to 1,500 amp/sq ft; and a molten salt temperature of 860° C. Ingots produced from electrorefined uranium crystals prepared with these operating conditions were substantially free of metallic impurities. The only impurities in the refined and consolidated metal were present in low or undetectable amounts.

Jan 1, 1965

By D. W. Feng

Thiosulfate as an alternative lixiviant for gold has received much attention in recent years due to the growing environmental concerns over the use of cyanide. Cu(II) is used to catalyze the oxidation of gold and ammonia is to stabilize Cu(II) in alkaline solution. However, the presence of Cu(II) enhances the oxidative degradation of thiosulfate. The high consumption of reagents has made thiosulfate leaching uneconomical to date, in comparison with cyanide leaching. Therefore, further investigations are required to leaching under low reagent concentrations over extended periods where reagent consumption is low and gold leaching rate is low as well. It is thus necessary to find additives to enhance gold dissolution in the thiosulfate leaching system. Electrochemical studies using rotating gold disc showed that the oxidation of gold in ammoniacal thiosulfate solution increased significantly in the presence of a small amount of thiourea and the beneficial effect increased with an increase in the thiourea concentration up to 7.2 mM. Thiourea improved gold extraction in the thiosulfate leaching of gold from a sulfide ore under low reagent concentrations. Excessive addition of thiourea inhibited the leaching of the gold ore. The decomposition of thiosulfate was reduced with the presence of thiourea. X-ray Photoelectron Spectroscopy (XPS) results indicated that thiou-rea likely decomposed to sulfide and formed gold sulfide species at the gold surface.

Jan 1, 2014

By M. T. Ityokumbul

The use of yield index, the product of the yield and gangue rejection, for the optimization of separation processes is presented. The characteristics of the yield index are contrasted with separation efficiency calculations and applied to laboratory froth flotation and washability data. Data from continuous froth flotation tests conducted to "optimize" froth flotation using process optimization software were also evaluated with the yield index procedure.

Jan 1, 1997