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By Xin Li, Hai-Xing Fang, Bing Xie, Hong-Yi Li

Chromium-containing vanadium slag (V-Cr slag) was obtained by an industrial smelting process of Hongge Ore, which is valuable vanadium-titanium magnetite to extract V and Cr in China. Sodium roasting thermodynamics of V-Cr slag in presence of oxygen were calculated to evaluate the reactivity of chemical compounds. Results showed that the oxidation of FeV2O4 was intensified in presence of Na2CO3 while the oxidation tendency of FeCr2O4 was far lower than that of FeV2O4. It was probably that reactions of impurities including Al2O3, SiO2 and Fe2O3 with Na2CO3 happened and the products can promote the oxidation of vanadium or chromium compounds in lower valence. Based on thermodynamic analysis, a two-step selective extraction process of vanadium and chromium was proposed. Extraction rate of vanadium was 88.6% while 7.0% for chromium in the first extraction step; extraction rate of 90.7% and 95.4% for vanadium and chromium, respectively, were obtained in the second step.

Jan 1, 2014

By Yuanbo Zhang, Zhixiong You, Zijian Su, Bingbing Liu, Guanghui Li, Guang Yang, Tao Jiang

Sodium stannate is widely used in the electroplating and tin alloy industry. But the traditional processes for sodium stannate production are characterized by long flowsheet, high production cost and strict requirement for the equipments, etc. In this study, a novel process for sodium stannate preparation from cassiterite concentrate and sodium carbonate via roasting in CO/CO2 mixed gas then followed by leaching was developed. The effects of roasting parameters on the Sn leaching efficiency were conducted. A Sn leaching efficiency of 77.2% was obtained under the optimal conditions. Sodium stannate (Na2SnO3·3H2O) with a purity of 95.8% was produced by the new process, which is better than that specified for the industrial first-grade product.

Jan 1, 2014

By PAULL. BROUGHTON

Commercial deposits of sodium sulphate are harvested from alkaline lakes that are widespread throughout semi-arid southern Saskatchewan and adjacent southeastern A lberta. Concentration of sodium sulphate occurs in undrained basins under semi-arid conditions. Precipitation runoff from land adjacen1 to 1hese basins leaches 1he mineral from the soils and carries it in solu1ion 10 the basins. The process may be largely subsurface, wherein spring seeps feed basins associated with buried (preg/acial) river valleys. Evapora1ion during summer concentrates salts in the brines, and chilling of water below sa/Uration poin1 during win1er resu//s in deposi1ion of sodium sulpha1e (mirabili1e) crystals on lake bo//oms. Sodium su/pha1e, commercially known as sa/1 cake, ranks second only 10 po1ash in cen1ral-wes1ern Canada's nonme1allic mineral production. // is recovered from su,face brines, directly from intermittenl salt beds, and, until recently, by solution mining of shallow subswface deposits. Sodium sulphate is extrac1ed from seven alkaline lakes and sail f/a1s in Saska1chewan and one in Alberta. Annual produc1ion is approxima1e/y a halfmillion tonnes. Manufacture of kraft paper is the mos1 significanl marke1 for salt cake, but addi1ional quantifies are used in the glass and detergent manufac1uring indus1ries.

Jan 1, 1984

By N Gupta, R Trivedi, S Bhandari

Managing blasting operations in four mines surrounded by villages is a challenging task. This study aims to compare the blast-induced flyrock as observed in opencast mines by predicting flyrock distance using a soft computing approach known as an adaptive neuro-fuzzy inference system (ANFIS) and Flyrock Predictor software based on empirical studies. Blast design and geotechnical variables such as linear charge concentration, burden, stemming length, specific charge, unconfined compressive strength and rock quality designation were selected as independent variables, while flyrock distance was used as a dependent variable. Out of 120 blasts, data from 100 blasts was used to train and test the ANFIS model. Flyrock distance for the remaining 20 blasts was used to evaluate the model. Flyrock distance has also been predicted using Flyrock Predictor software based on an empirical approach using the same data sets as those used for ANFIS. Performance indices like root mean square error (RMSE), mean absolute error and coefficient of determination (R2) were evaluated to compare the reliability of ANFIS and Flyrock Predictor quantitatively. ANFIS was found to be a better predictive tool, with 1.75 m RMSE and 0.966 R2 compared to Flyrock Predictor, which returned RMSE and R2 values of 2.48 m and 0.932 respectively.CITATION:Trivedi, R, Singh, T N, Gupta, N and Bhandari, S, 2015. Soft computing approach to predict blast-induced flyrock, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 455–462 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Verya Nasri, Kevin Akbarpour, Hiva Mahdavi

"The Sheppard East Light Rail Transit (SELRT) project comprises approximately 13 km of new light rail, which will be constructed along Sheppard Avenue East in Toronto. There is a 380 metre long section of the route that will be constructed as tunnel below Highway 404, which is owned by the Ministry of Transportation Ontario (MTO). MTO has published guidelines for tunneling under its highways. An impact analysis was undertaken to predict the surface settlement and angular distortion of Highway 404 resulting from the construction of the twin tunnels. The results were then compared to the performance criteria defined in MTO’s guidelines. As a result of this analysis, it was necessary to request an adjustment to MTO’s current performance criteria. This paper presents details and results of the impact assessment, approaches taken to satisfy the requirements defined by MTO, and provides details of the adjustment permitted by MTO. INTRODUCTION Several major rapid transit projects are planned for the Greater Toronto and Hamilton Area (GTHA) located in southern Ontario, Canada. These projects are part of The Big Move (Metrolinx 2008) initiative, a 25-year, and $50 billion plan aimed at improving regional transportation. Metrolinx, an agency of the Government of Ontario, is now working collaboratively across the region to deliver major Toronto rapid transit projects to the GTHA. One such project is the SELRT. The line will largely run along Sheppard Avenue East on the surface, except for a crossing of Highway 404 where it will be constructed using a combination of open cut and bored tunneling methods. AECOM has been retained by Metrolinx as the Technical Advisor (TA) to develop the Reference Conceptual Design (RCD) and Project Specific Output Specifications (PSOS) for the project. Also, Infrastructure Ontario (IO) is the Co-Sponsor and CH2M HILL is Metrolinx’s Owner’s Engineer (OE) & Project Management Support (PMS) for the new LRT lines. This paper presents information on the tunneling settlement analysis and further work undertaken to satisfy the MTO’s requirements."

Jan 1, 2016

By M Dixon, T OÆShannessy

Melbourne Water (MW) is responsible for a section of existing gravity trunk sewer servicing the Melbourne central business district, Docklands, Port Melbourne and other adjacent areas, known as the Melbourne Main Sewer (MMS). MW has determined that the 2.2 km long 110 year old sewer will not adequately service these areas into the future or provide the level of reliability needed. The Melbourne Main Sewer Replacement project (MMSR) involves the replacement of the MMS with a new gravity sewer main and six key manhole shafts, known as the Melbourne Main Reliever (MMR).The majority of the MMR sewer tunnel is situated south of the Yarra River and will be constructed using an earth pressure balance (EPB) tunnel boring machine (TBM) and will be lined with precast concrete segments. The tunnel will be 2.4 m internal diameter and will have a 1.8 m diameter glass fibre reinforced plastic (GRP) sewer pipe positioned within it. This project represents the first large-scale, modern, mechanised tunnel project in MelbourneÆs Yarra Delta Quaternary sediments. There is little precedence known to the authors of similar scale tunnelling projects in these particular geological units. During the recent detailed investigation and design stages of the project, significant effort has been spent on characterising the geotechnical conditions along the alignment and predicting the effects of the new tunnel on the existing environment. Some of the key design issues that have been identified and managed through the design process include short-term surface settlement due to tunnel excavation and the predicted effects on surface infrastructure, potential spalling of the steel fibre reinforced concrete segments under full TBM ram loads and tunnel lining design in geological units with highly variable stiffness.Construction of the new MMR sewer tunnel is expected to commence in mid-2008 with a capital cost of approximately $160 million. Sewer system commissioning is scheduled for completion by early 2012.

Jan 1, 2008

By Davi Silva Braga

Controlar o perfil térmico dos fornos de uma planta de pelotização é essencial para se garantir a qualidade das pelotas e manter a competitividade da produção. A medição online de variáveis-chave é restrita devido às condições da planta ou limitações tecnológicas, fazendo-se necessário a utilização de um modelo matemático (Soft Sensor) para estimar essas variáveis e, então, exercer maior controle sobre a qualidade e custos do processo. Através de balanços térmico e mássico, o modelo é capaz de predizer o perfil térmico das pelotas e as perdas, térmicas e mássicas, além de simular mudanças no processo e implicações no consumo de combustível. Com o modelo, observou-se a possibilidade de redução de 5% de perda térmica, resultando em redução de 2% do consumo de combustível, devido à melhora da recuperação de calor da zona 2 do resfriador para a pré-queima 1 do forno grelha. O trabalho foi realizado na planta da Vallourec & Sumitomo Tubos do Brasil (VSB).

Aug 17, 2017

By M. Tardif, F. L. -Lavoie, M. Ruel

"In mineral processing, it is often very difficult to reliably measure several key operation variables. The harsh environment and high temperature encountered in pyrometallurgy processes lead to some difficulties when selecting the instruments, valves and actuators. If an important variable cannot be measured or manipulated adequately, controlling it can really become a big challenge. Sometimes, it is simply impossible to find the perfect equipment for the task. To help overcome these difficulties, a different approach is required. This approach will not correct the inherent problems related to the instruments and valves, but will cope with these problems. This article will demonstrate how modern process control techniques can be used to solve complex problems while remaining easy to implement. In this article we will described how soft sensors and multivariable fuzzy logic control were implemented at Koniambo Nickel to stabilize the furnace feed and allow for safe and reliable operation of an 80 MW DC arc furnace.INTRODUCTION Process Overview The process plant at Koniambo Nickel SAS is located in the North Province of New Caledonia, 310 km north of Noumea. The nickel-bearing ore is mined in the nearby Koniambo massif. After being screened and crushed, the ore is transported to the processing plant using a 12 km conveyor. After stacking in two blending piles, the ore, containing 2.3% nickel, is fed to the processing plant where it will go through the NST process (Nickel Smelting Technology) before being sent to refining and shotting. This article will focus on the improvement to control of the NST processes. The first steps of this process consist of milling the ore and removing all moisture through calcining (Figure 1)."

Jan 1, 2017

By M Hilden, G Forbes, Z Ye, M Yahyaei, F Reyes, V Jokovic

Soft sensors offer several practical advantages for the process control of comminution circuits by combining multiple conventional sensors and other data sources with real-time analysis using mechanistic, phenomenological or machine learning models. While there has been a growth in the use of machine learning techniques for developing soft sensors in minerals processing applications, this paper describes advantages and challenges of using soft sensor models developed on the basis of process knowledge. Recent experience with three new soft sensor technologies developed by the authors are discussed. The Mill Filling Inference Tool which has been implemented at several mine sites, compares SAG mill load cell and power draw measurements with outputs of a semi-mechanistic power model to estimate the mill ball and total filling in real time. The progressive wear of the mill liners is modelled, allowing the model to correct the load mass due to the mass loss automatically and to estimate the charge trajectory. This information enables the mill to be operated more confidently near its limits. A coarse-ore stockpile soft sensor as been recently developed using a 3D cellular automata-based model to track ore size throughout the pile, and estimating the live capacity and size at each stockpile feeder to the primary mills. Finally, a hydrocyclone soft sensor is being developed to monitor performance using available hydrocyclone models to estimate the size and flow balance around the cyclone in real time. The model-based soft-sensor approach aims to synthesise and analyse existing data and provide operators and engineers with process- and model-relevant information that can facilitate making better process decisions. Maintenance data has proven useful for model development as it allows soft sensors to automatically adjust and compensate for the effect of progressive wear, for example for mill liners, thus helping the models to maintain calibration throughout the equipment life.

Aug 24, 2022

By Randall D. Peterson

Strip mining with draglines and other surface equipment has traditionally been the method of choice for mining shallow deposits. This is particularly true for soft deposits that require little or no blasting. High rates of productivity and low operating costs have set this standard. However, these methods can be improved. Strip mining methods are batch processes and difficult to accommodate in processing. Moreover, they are encumbered with overburden removal, reclamation expense, and human inefficiencies. This paper describes the invention of a novel shallow earth mining technique called the Softwall Mining Method. Softwall Mining is an adaptation of longwall mining for loose earth conditions. The method was specifically invented for recovering phosphatic clay ore from beds in North Central Florida, but is likely to be suitable for a number of other minerals as well. Potential deposits for which the method may be well suited include placers, disseminated deposits in soft host rocks, bauxite, soft coals and lignite deposits, and other deposits where overburden will subside readily and where the ore can be hydraulically broken and slurried. Unit operating cost advantages are expected over the current dragline systems used. The Softwall mining advantages are its high rates of productivity, control and automation of the mining process, reduction of dilution and waste, and elimination of the majority of stripping and reclamation.

Jan 1, 1998

By Semih Perdahcioglu, Arthur E. Morris

"The curricula for the majority of Materials Science and Engineering programs is devoid of all but the most rudimentary coverage of the principles of material and energy balance calculations. As a result, graduated engineers that need to make such calculations are faced with three unpalatable options. First, attempt to learn the subject by attending workshops or short courses sponsored by corporations or industry groups. Second, outsource the needed work to a consulting engineering company. Third, purchase a software package that's capable of simulating a process. Each of these options require a considerable investment of employee time and effort. The first option might be the best if suitable computational software was readily available. We review the recent development of such software, which is entirely based in Excel. The software tools include a thermodynamic database, tools for multiple computations, and a flowsheet simulation program. These tools employ teaching by simulation.IntroductionPracticing engineers often come up with situations where they must learn a technical subject that they didn't cover in their college classes. One possibility is to obtain a couple of texts on the subject, and delve in. Or, they may sign up for an intensive short course where they can get personal instruction and guidance. But the first option requires a lot of study time, and the second option may not provide the specific instruction (or intensity of instruction) required to appropriately master the subject. Here we look at ways of using simulation techniques to learn the methodology for making material and energy balances on industrial processes.Industrial heating processes have undergone many changes over the past dozen years, as vendors have introduced new heating equipment designed to recover the greatest possible amount of heat from the fuel, and to meet stringent environmental challenges for emissions (especially NOx). Even though the recent unprecedented drop in price of natural gas may have altered the urgency for improving a plant's energy efficiency, the need is still there. Until recently, there was a dearth of readily-available software for process engineers to use for simulating a plant's flowsheet. The good news now is the existence of several Excel-based software tools that make the calculational process much easier. [ 1]. Plant engineers may also be interested in a DOEsponsored program[2] which allows plant-wide and ""what-if' analyses of the energy balance."

Jan 1, 2013

By Varadarajan Seshadri

The performance of mould fluxes in satisfying its quality requirements can have a significant effect on the efficiency of the continuous casting process and on the surface quality of the products. This performance is affected by various parameters including the characteristics of the mould fluxes, the quality of the steel being cast and the operational conditions of the caster. The extremely complex relationships involving the parameters mentioned above make it very difficult to have simple criteria for selecting mould fluxes for casting a certain grade of steel in a continuous casting machine. These difficulties led steelmakers and mould flux suppliers to select mould fluxes based mainly on plant trials. In the present work, a software to help in the analysis and development of mould fluxes for continuous casting was developed. This software includes several models for prediction of mould flux viscosity and consumption. A mathematical model was also used to predict the heat flux through the mould flux. The proposed methodology was applied to continuous casting of crack sensitive steels. Some of the results given by this software are presented, discussed and compared to plant data.

Jan 1, 2003

By Varadarajan Seshadri

The performance of mould fluxes in satisfying its quality requirements can have a significant effect on the efficiency of the continuous casting process and on the surface quality of the products. This performance is affected by various parameters including the characteristics of the mould fluxes, the quality of the steel being cast and the operational conditions of the caster. The extremely complex relationships involving the parameters mentioned above make it very difficult to have simple criteria for selecting mould fluxes for casting a certain grade of steel in a continuous casting machine. These difficulties led steelmakers and mould flux suppliers to select mould fluxes based mainly on plant trials. In the present work, a software to help in the analysis and development of mould fluxes for continuous casting was developed_ This software includes several models for prediction of mould flux viscosity and consumption. A mathematical model was also used to predict the heat flux through the mould flux. The proposed methodology was applied to continuous casting of crack sensitive steels_ Some of the results given by this software are presented, discussed and compared to plant data.

Jan 1, 2003

By S. Motoiu

Data acquisition is widely used for controlling flash smelting furnaces. A Romanian smelter from which a large amount of data can be collected uses such a technique. A computer program was developed for interpretation of the data. Inputs to the program are the process data files. Abnormal data are identified using standard statistical techniques; they can be edited if necessary. The following methods can be used for the analysis: linear correlation (single or multiple), polynomial correlation or comparison of two average values. Time variation graphs and histograms can be displayed. The random balance method was used for determination of significant parameters influencing the process performance. Not all process parameters are recorded, and some of them are not even measured. The software can compute some of these parameters such as: air flow rate required and the oxygen content of the gas: exiting the reaction tower. The software was used for the interpretation of a large amount of process data. The analysis showed that the process did not operate properly at some times.

Jan 1, 1999

There are several simulators available and are being used for analysis, improvement and optimal control of the grinding process. However, these tend to be developed on informal software engineering methodologies. The informal approach is not suitable for long term development and a formal design methodology is necessary to develop efficient, error-free, and easy-to-use and to maintain software. In meeting this goal, basic concepts of a software model for describing the mineral process objects has been proposed. The software model forms the basis for software design and efficient implementation of the simulation. This paper describes the development of software models for grinding circuits. The work constitutes the theoretical foundation for the development of an advanced simulator for comminution.

Jan 1, 1995

By Kal V. S. Sastry

Mathematical and expert system models are being used extensively for mineral process engineering. There exist no standardized methodologies for their computer implementation. In meeting this need, this paper introduces the concept of a process software model, or simply a software model and presents a two-step methodology for its development involving software model specification and development. The software model specification is to be performed after extensive discussions with the ultimate users of process software based on which the software model is developed. These software models provide a formal basis for the design and construction of software objects corresponding to the real world process objects.

Jan 1, 1994

By Ángel Nuñez-Meza, Juan Alfaro-Bernedo

La intención del trabajo reportado en este artículo es la de superar las limitaciones que conlleva no trabajar con modelamiento previo, base de datos y un enfoque sistémico. En atención a esta idea, el estudio desarrolló un software para dos circuitos (directo e integral). Como resultado, se recomienda desarrollar un software integral de toda la planta concentradora —chancado, molienda, flotación y eliminación de agua— con diferentes tipos de circuito, en un solo sistema (enfoque holístico); además de migrar a un modelo de servicio en la nube, con el objeto de poder contar con completa disponibilidad.

Sep 30, 2019

By Lynn B. Hales

The Supervisory Computer System at Cities Service copper mine and concentrator at Miami, Arizona was installed at Pinto Valley in the spring of 1975. Design and specification [l] of the digital system was initiated jointly by key plant personnel at Pinto Valley and staff of Cities Service Research and Development Company. The Pinto Valley digital system [2] may be classified as a supervisory control system of hierarchical design. There are three fully independent satellite computers which retrieve and reduce the raw plant data from each of the three main operating areas - the primary crushing plant, the fine crushing plant, and the grinding and flotation plant. While the three satellite computers are core resident systems, the master computer is a disc-based operating system which also interfaces with a computer controlled on-stream x-ray analyzer system. Figure 1 illustrates the basic system configuration [3]. The software systems required to support a large system are quite diverse and vary greatly in function. The philosophy followed in dividing the software into three categories was designed to: 1) fully utilize existing process knowledge of technical staff; 2) delegate certain software tasks to outside sources already skilled and trained in software development; and 3) maintain final control over the design and operation of each system.

Jan 1, 1976

By M. H. Pettibone

Sohio Petroleum Company's new L-Bar uranium mill near Grants, New Mexico. refines 2722 kilograms of yellowcake daily from 1360 metric tons of ore produced at Sohio 's J.J. No. 1 mine and other nearby mines. This paper follows the ore from the mine through the various processing steps - semi-autogenous grinding, acid leaching , countercurrent decantation, solvent extraction , ammonium diuranate precipitation, washing and drying, and tailings disposal.

Jan 1, 1978

By Andrew Moran, William H. Walton, Matthew D. Emrick, Mary C. Nodine

"A rapidly growing company in the northern US needed a large auditorium built into a dolomite bedrock hillside. The structure required an 80-foot-deep earth retention system independent of the auditorium foundation and superstructure. Allowable wall movements were limited to less than two inches. A 60-foot-tall permanent shotcreted soil and rock nail wall was designed for excavation support. The soil and rock nail wall utilized both active (post-tensioned) and passive nails, with capacities and installation angles optimized to address varying soil and rock conditions and to support heavy surcharges. The wall was configured with three two-foot-wide benches to facilitate controlled blasting and removal of more than two million cubic yards of soil, limestone and dolomite bedrock, and featured a permanent cast-in-place concrete face and a robust waterproofing and drainage system. A 20-foot-high reinforced concrete retaining wall was required at the top of the soil and rock nail wall to raise grades, resulting in a large surcharge.Design of the soil and rock nail wall was initiated less than three months before the start of construction, requiring expedited geotechnical explorations, analyses, design, and construction that would occur simultaneously. Design changes were made to address the discovery of a weak clay residuum seam at depth running along the base of the excavation, as well as significant changes to the building footprint made after the start of construction. Extensive performance monitoring was conducted during construction to measure vibrations and movements.Introduction and Project BackgroundA fast-growing company in the northern United States had a need for 600,000 square foot, 11,000 seat auditorium as part of its campus expansion. The auditorium was built underground, into a hillside to preserve the views of rolling terrain and farmland beyond. It featured a green roof and rockwork facing that mimicked regional geologic formations. The sixstory building required up to 80 feet of earth retention, including 60 feet of excavation beneath existing grades.As concepts for the project evolved, it became apparent that due to the geologic conditions, space limitations on site and the depth of cut required, a standard counterfort wall system would not be feasible. With groundbreaking for the building three months away, Thornton Tomasetti (structural engineer) engaged GEI Consultants, Inc. (wall design engineer) to design a 1,600-foot-long permanent soil and rock nail wall to support the excavation. The wall design engineer implemented a geotechnical exploration program immediately and began the design process, coordinating closely with Nicholson Construction (specialty"

Jan 1, 2017