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By M. Giralico

Optimized mixer settler designs will now handle flows of over 25,000 GPM. The size and expense of the equipment hamper experimental settler optimization efforts. Computational Fluid Dynamics (CFD) is a timely and predictable tool for settler design development. In the past, CFD has been used to evaluate only the flow field in pumped and auxiliary tanks. A similar numerical analysis is used to evaluate settler flow and phase separation. Phase separation is analyzed using multiple species for the aqueous and organic phase. Experimental validation shows good agreement between the computational and experimental solutions in both flow field and phase separation. The computational model is used to show performance differences between various choices of settler geometry, liquid depth, with variable flow rates. Understanding the differences allows the development of optimized settler designs. System improvements are predicted to lower entrainment levels further and/or allow new smaller footprint designs. This paper focuses on the major design components of the settler and how future technological advances will lead to further improvements in their design. LIGHTNIN?s new designs will handle tomorrow?s production requirements, while maximizing profits.

Jan 1, 2003

By John A. Herbst

Professor A.M. Gaudin and his students at MIT were dedicated to understanding the fundamentals of mineral processing and as a consequence were constantly searching for better quantatative descriptions of size reduction, liberation and mineral separations. I have had the good fortune of meeting Professor Gaudin and working with many the modeling pioneers who followed him. I have observed first hand the refinement of mineral processing models as they increased in realisticness moving up the steps of the pyramid (see figure below) from pure empiricism to the current pinacle of physics based models. During this journey our industry benefited significanbtly as model prediction errors were reduced from ± 20% to ± 1%. Unit operation and plant simulations improved in accuracy and speed of calculations.

Sep 1, 2012

By K. Harris, J. B. Wahl

Ni-base superalloy cast materials provide an outstanding balance of high temperature strength, fatigue resistance, oxidation resistance and coating performance and can be produced to very tight tolerances in extremely complex configurations, such as axial and centrifugal integral cast turbine wheels. As a result, cast superalloys are used in the most demanding applications of aero and industrial gas turbine engines. Use of these materials is expanding to smaller microturbine, turbojet, turbocharger and missile engine applications due to this unique combination of desirable properties. This paper will present an overview of the application of investment cast Ni-base superalloys and process capability to small turbine and missile engines.

Jan 1, 2010

By J. S. Becker

Technology developed and first implemented in the United Kingdom enables very low grade aluminum scraps containing oils, organics, plastics and ferrous metals to be directly charged, without pretreatment, into a unique melting furnace. The system has been in full scale production for four years. The oxy-fuel-based furnace design incorporates internal afterburning in the furnace's hot zone, producing excellent thermal efficiency and very low emissions. The furnace is inherently low in NOx. This paper will provide both theoretical background and extensive operating results for this new melting concept. Applications describing both purpose built new furnaces and retrofits of existing reverberatory furnaces will be presented. Extensive operating emissions data will be presented.

Jan 1, 1997

By Brandon R. Ball

An investigation of the effects of ozone and ozone-induced hydroxyl radical on reducing whole effluent toxicity is described and discussed relative to the application of ozone for industrial water treatment. Results from operation of an ozone system treating industrial effluent from a lead and zinc mine in Colorado are presented. The mine discharges 1,000 gpm of wastewater into a tributary of the Arkansas River and has historically exceeded Whole Effluent Toxicity (WET) limits and on occasion has exceeded numeric limits for copper, ammonia, and cyanide. Based on results of a Toxicity Identification Evaluation (TIE) conducted on the effluent and individual process waste streams, the source of effluent toxicity is believed to be primarily associated with organic reagents used in the milling process. Based on test results, an applied ozone to COD ratio of 3: 1 by weight and a contact time of 30 minutes was found to be effective for reducing whole effluent toxicity at pH 11 but not at pH 7, indicating oxidation by hydroxyl radical to be the dominant mechanism responsible for toxic-ity reduction. At an applied ozone to COD ratio of 3:1 and a pH of 11, toxicity was improved from 0 percent survival to 100 percent survival for Ceriodaphnia dubia and fathead minnow (Pimephales promelas) based

Jan 1, 1996

By Peter Sylvén, Darwin Morales

Despite being crucial for the smelting process, furnace tapping using oxygen lances has not been considered an operation that brings value. Therefore, these important tools have not seen a significant change in over 100 years. Problems related to the use of oxygen lances include: • Inaccurate tool: causing damages shortening the life of the taphole refractories. • Safety: extended exposure to the operator in an unsafe area of the furnace. • Cost: high oxygen consumption & high lance consumption. • Time consuming and frustrating to connect one lance to another. This paper will suggest a very good solution; new concept thermal lances. We will show how these provide an outstanding performance for a more efficient, faster and cost-effective furnace tapping operation. These new lances are very accurate tools that enable the operator to perform a more controlled operation; resulting in longer taphole life, fewer repairs and less down-time.

Jan 1, 2016

By Robert W. Row

Advanced physical coal cleaning processes that are now under development may remove significantly greater fractions of pyritic sulfur and ash than do commercial coal cleaning processes at comparable heating value recoveries. These processes may be useful for reducing sulfur dioxide emissions from electric utilities and other emission sources. However, little work has been done to determine their applicability to any major coal market. The northeastern states of the United States are interested in burning more coal, but with further sulfur dioxide emission restrictions. Their nearest coal sources are relatively high sulfur Northern Appalachian coals. The project discussed in this paper, which is scheduled to be completed in June 1985, has the objective of technically and economically evaluating various coal supply scenarios involving five selected advanced physical coal cleaning processes; and comparing the economics of them with alternative fuel supply options open to the northeastern users.

Jan 1, 1985

By Kevin Vander Tuig, Tim O’Rourke, Rick Vincent, Doug Lopata, Kellie Rotunno, Dan Dobbels

"The Northeast Ohio Regional Sewer District (NEORSD) was required under the Federal Clean Water Act and U.S. Environmental Protection Agency’s (U.S. EPA) Combined Sewer Overflow (CSO) Control Policy to develop a Long Term Control Plan (LTCP) to reduce or eliminate overflows from its permitted CSO outfalls. The LTCP was completed in 2002. Key components of the plan include: 26 miles (42 km) of deep storage and conveyance tunnels providing a total CSO storage volume of 325 million gallons (MG) (1.2 billion liters); over 30 miles (48 km) of consolidation sewers to route CSO control flows to the tunnels; and associated diversion/inflow control structures and drop shafts. Final design and construction of the initial phases of the LTCP are completed or underway. Advanced planning of the final phases began in April 2013. This paper summarizes this advanced planning process and, specifically, how hydraulic performance and tunnel design and construction considerations were balanced to eliminate unnecessary projects and shafts, reduce implementation risks, and reduce program costs by approximately $650 million. BACKGROUND The Northeast Ohio Regional Sewer District (District) serves an area of approximately 350 square miles (SM) (907 km2), including combined (81 SM; [210 km2]) and separate (269 SM [697 km2]) sewer systems that discharge to three wastewater treatment plants in the greater Cleveland area. The service area, shown in Figure 1, is divided into three districts—Easterly, Westerly, and Southerly—each having its own interceptor system and treatment plant, ranging in wet weather treatment capacities from 100 to 735 million gallons per day (MGD) (378.5 million to 2.8 billion L/day). The system includes 124 permitted combined sewer overflow (CSO) outfalls overflowing into the region’s tributary streams, Cuyahoga River, and Lake Erie."

Jan 1, 2016

By Andreas Hucke

For the roadway design in the German hard coal mining industry, an advanced combined planning system has been applied during the past 20 years. The German mining industry is working with single entry roadways system. After first longwall passage the roadways will be stabilised with side wall building material packages. Later this roadway will be used again for the second retreating longwall. The intention of the implementation of several different design methods for the planning of the roadways is to enhance the reliability of the results. On one hand the planning system uses numerical simulation and physical modelling in addition to analytical and empirical methods. On the other hand in-situ monitoring and analysis during the roadway development will be used to verify and calibrate the numerical and physical models. Especially before the implementation of new support elements in underground, this system is suitable and reasonable because the new support elements will be tested in the physical and numerical simulation prior to cost intensive underground tests. The interaction between the numerical and physical modelling in comparison with underground monitoring and analysis during development and the later use of roadways will be shown with some examples. The first example shows a rock bolted rectangular roadway which will be mined at both sides of the roadway. Different support and roadway building material package systems are investigated under various stress conditions. The results are utilised to optimise the roadway support and the roadway side package systems. The influence of different points in time of the installation of several support elements in a combined arch and bolted roadway is shown as another example. Two different types of support systems are compared within the physical models. These models are used as a base for ongoing numerical analysis and simulation to find out the ideal point of time to assemble the different support elements. The last example handles the influence of slickensides in the roof of arch shaped roadway on their stability. Different slickenside positions and densities are investigated and classified.

Jan 1, 2006

By T. Bohmer, L. Auret, N. Pillay, Z. Horn, P. Rambalee, A. Haasbroek

As part of a broader digital technology-enabled transformation programme, a major mining company is systematically implementing Advanced Process Control (APC) solutions and associated instrumentation throughout their operations. This paper highlights the approach and benefits of this holistic approach for a specific instrumentation installation, and APC installation at a South African coal processing plant. For the coal processing plant under consideration, a systematic approach was followed. Process sections/units are considered from upstream to downstream processing. APC solutions are designed for each process section and each process section is interrogated in terms of availability of sufficient process measurements to ensure stable, capable, and ultimately, optimised performance. Where insufficient process measurements are available, instrumentation upgrades are implemented. Finally, APC solutions are implemented, and evaluated in terms of productivity, safety, health, and environmental benefits. For the flotation section, an opportunity was identified to install froth sensors. The installed froth sensors provide measurements on froth velocity, bubble size, height, colour, and stability. The improved visibility that the froth sensors provided on the flotation process resulted in quick gains in terms of productivity: for example, instability in the feed to the flotation section could be quantified. This resulted in targeted process troubleshooting in an upstream thickener, and subsequent improvement of process stability, and reduced feed variance. The measurements from the froth sensors were further integrated in an APC solution. Proportional mass pull contributions per cell and per line can be inferred from the froth sensors, serving as controlled variables, while pulp level set points serve as the manipulated variables. On-off tests indicated that the advanced process control solution provided increases in yield and product quality.

Sep 1, 2021

By D. Groenveld, M. Rozou

"Recent trends move towards automation, smart sensors, internet of things, powerful DCS, and more data. Are those trends already utilized in a real time production environment? Today operators still have to monitor several complex processes at the same time and predict their behavior based on an overwhelming amount of data available.The fact of the operator being overloaded and humans being unable to process multivariable problems shows the need of a tool merging essential data and providing consistent, sound decisions for long-term profitability.This paper shows a successful execution of ABB’s process improvement services in Aitik (Boliden SA), a copper mine located in Sweden. Soft sensors, fuzzy rule blocks and model predictive control were seamlessly integrated in the control system of the grinding area, resulting in proper control of mill loads and particle size without violation of any constraints.INTRODUCTIONDepending on the ore characteristics and the targeted plant capacity, the design of the grinding circuit may vary significantly. Typically, the circuit consists of several mills (rod, ball, SAG, AG) in series and/or parallel with a number of classifiers and sumps at appropriate locations. The goal of the grinding section is to reduce the ore particle size to a level that enables efficient separation between gangue and precious metals in the subsiding processing step. The trade-off between quality and quantity has to be made. It is also crucial to execute this process step at the lowest possible energy and grinding media consumption.An optimal grinding process controller must manage to maintain a given fresh feed level while keeping the product size within a given range without violating any constraints such as power, torque or load limits. To accomplish the aforementioned, it is necessary to manipulate the ore feed rate, water feed rate and the mill speed. The most significant disturbances adding another degree of complexity to this control problem are ore hardness and the amount of circulating load."

Jan 1, 2016

By E. Gallestey, D. Groenveld, F. Kolb, M. Rozou

"Recent copper price evolution pushes modern mining industry even harder to achieve highest production with maximum efficiency. Operations are bound by numerous contractual and environmental conditions that bring a high degree of complexity to both the operators controlling the process and the plant managers assessing the circuit’s potential and setting the production goals.Advanced process control (APC) for grinding is one important tool to operate this most energy intense area in an optimal way, finding the optimal trade-offs between highest throughput, energy efficiency and product quality based on variable ore properties, production targets and management priorities.ABB’s state of the art control and optimization software platform enables user to design a controller based on model predictive control (MPC). The paper and the presentation show the technology used and the results achieved through an APC controller installed in a pilot project in Aitik (Boliden SA), Sweden. Furthermore, possibilities to interconnect grinding with other areas as stockpile management and flotation with various interconnected APC controllers will be shown. Finally, an example of the return on investment and the payback times based on the increased throughput and better product quality will be presented.INTRODUCTIONDepending on the ore characteristics and the targeted plant capacity, the design of the grinding circuit may vary significantly. Typically, the circuit consists of several mills (rod, ball, SAG, AG) in series and/or parallel with a number of classifiers and sumps at appropriate locations (see Figure 1).The main goal of the grinding section is to reduce the ore particle size to a level that enables efficient separation between gangue and precious metals in the subsiding processing step. The trade-off between quality and quantity has to be made. At the same time, it is also crucial to execute this process at the lowest possible energy and grinding media consumption."

Jan 1, 2015

By M. V. S. Cavalcante

The quality of iron ore pellets, represented in terms of parameters such as cold compressive strength (CCS) and Tumble Index (TI), has a strongly influence on the productivity and energy of reduction furnaces like the blast furnace and on the quality of hot metal or liquid iron. The main objective of pelletization operations is to produce iron ore pellets of desirable specifications and ensure high levels of plant productivity and energy efficiency. Advanced process control of an industrial iron ore pellet induration process using a soft sensor for pellet quality and fuzzy-logic based control algorithm is described in this paper. The pellet quality soft sensor consists of a rigorous mathematical model of the induration process and a statistical model for the pellet quality parameters. The mathematical model is based on the fundamental principles of heat and mass transfer between gases and pellets, kinetics of drying and condensation of moisture, combustion of coke, calcination of limestone, and melting and solidification of pellets. The predictions of wind-box temperature profiles are in close agreement with the measured profiles. The time-temperature profiles of the pellets during induration, along with raw material characteristics and induration process operating conditions, are used as inputs to the quality model to predict cold compressive strength and the Tumble Index. The predictions of the quality soft sensor along with the rules based on fuzzy-logic derived from simulation results and operator experience are then utilized to control the induration process to achieve precise control of the quality parameters and to optimize the induration process in terms of fuel efficiency and productivity. The mathematical model is also utilized as a soft sensor for temperature, moisture and composition profiles of pellets and gases. Results of implementation of this model-based control strategy on an industrial scale induration process will be presented. Keywords: iron ore, pelletization, simulation, process control, optimisation

Sep 1, 2012

By I. James, R. J. Durrheim, M. S. D. Manzi, O. Valeshin, J. Lepine, L. V. Socco, C. Colombero, A. Malehmir, M. K. Rapetsoa, M. Sihoyiya

The FUTURE project aims to enhance seismic surveying in South African mining by integrating advanced acquisition technologies. In this paper, we detail surface and underground seismic surveys at the South Deep gold mine as part of the project. Surface seismic acquisition used co-located broadband micro-electromechanical sensors, one and three component recorders connected to geophones, distributed acoustic sensing using a straight fibre optic cable, along with a 6 ton broadband seismic vibrator operating with 4–180 Hz linear sweeps. In addition, underground surveys employed a combination of straight, and helically wound fibre optic cables, cabled-based and nodal sensors, along with a 500 kg drophammer mounted on a skid steer bobcat. The surface and underground seismic arrays were time synchronised using a GPS-time transmitter to allow for accurate seismic data recording in a GPS-denied environment. Results show the efficacy of these techniques in acquiring high-resolution seismic data, revealing detailed subsurface geological structures and mineralisation down to 3500 m below ground surface. Surface data revealed clear seismic reflections corresponding to the Black Reef and Ventersdorp Contact Reef. An underground P-wave velocity model exhibits low velocity anomalies that are associated with fracturing, while a P-wave reflection stack section shows significant reflections and a degree of faulting below the tunnel floor that was not observed on the surface reflection seismic data. We highlight the potential of these technologies to enhance safety, efficiency, and sustainability in mining. This study sets a benchmark for future reflection seismic surveys, paving the way for safer, more efficient, deep mineral exploration and extraction practices.

Jan 12, 2025

By Reinhard Gnilsen

Soil Nail walls, like any other structure, must meet high standards of design to be acceptable to the public and owners. On the other hand, the concept of soil nailing trails behind other structures in terms of defined design criteria that are commonly acknowledged. This is not to say that soil nail walls need to be less safe or less conservative than alternative more conventional concepts. Instead, the lack of established design criteria and design methodology entails that rules of thumb from past experience, overly simplified calculation assumptions, and the engineers' common sense judgement must substitute for a complex analysis of true stability and wall performance. Those "design approaches" must be conservative to ensure an adequate structure. Also, soil nailing may not be perceived prudent where site conditions are considered beyond past experience. For instance, site conditions may be perceived out-side the scope of soil nailing applicability where walls are very high, soil parameters variable or low, or nearby buildings close to the wall edge. The latter relates in particular to deep

Jan 1, 1988

By Kenshi Kawabata, Mitsuji Ueda, Junko Umeda, Katsuyoshi Kondoh, Kantarou Kaneko

Solid-state recycling process of in-house scraps of machined magnesium (Mg) alloy wastes has been established to directly produce wrought materials via the repetitively plastic deformation by Roll-compaction (RCP) and the conventional hot extrusion. The coarse chips, wasted in machining AMX602 (Mg-6Al-0.2Mn-2Ca) cast billets used for the gate bar used in Electronic Toll Collection (ETC) of the high-way system, were employed as the input materials in this study. RCP process enabled to serve coarse Mg alloy powder consisting of refined grains and intermetallics with no re-melting. They were easily consolidated by hot extrusion, and their wrought alloys showed both homogeneously refined grains less than 1~2 µm by dynamic recrystallization and randomized texture by repetitive plastic deformation on the input wastes. These materials revealed extremely advanced mechanical properties of high tensile strength of 356MPa and high ductility of 14.8%, compared to the originally virgin materials with 270MPa TS and 5% elongation. When applying the same Mg alloy wastes via RCP process to the mass production in the company, the large-scale extruded materials also indicated the superior tensile properties. It means that this direct solid-state process is held as “Up-grade recycle of metal wastes”.

Jan 1, 2008

By Chaoxun Zhao, Daniel Tao, Craig Blue, Narendra B. Dahotre, Rick Honaker, Bhupendra K. Parekh, Hongyang Han

Equipment wear and corrosion have significant adverse impacts on the operating cost and efficiency of mineral processing plants. In this project advanced surface enhancement technologies are being investigated to decrease the wear and corrosion rate of metal surface. Enhanced metal surfaces are achieved through surface conversion, enrichment, and coating by use of advanced High-Density Infrared (HDI) and other technologies. Studies have been done to determine the effects of process parameters on surface properties and identify optimum conditions. The microstructure of the enhanced metal surfaces was characterized by SEM, EDS, and microindentation. Laboratory wear testing was carried out to investigate the wear performance and the viable coating candidate was determined.

Jan 1, 2005

By Vincent Tricot, Daniel Altier, Roger Storry

"INTRODUCTION The Liantang / Heung Yuen Wai Boundary Control Point (BCP) project, located in the north-east New Territories of Hong Kong, will form the seventh land crossing between the Hong Kong Special Administrative Region (HK) and Shenzhen in China (Figure 1). The BCP project comprises an 11km long dual two-lane trunk road linking the border crossing facility to the existing road infrastructure in HK and when completed it will facilitate future regional development and alleviate frequent traffic congestion at the existing Boarder control points.In December 2013 Dragages Hong Kong (a member of the Bouygues Construction Group) was awarded the 5.4km long Contract 2 section of the project, including the 4.8km long Lung Shan Tunnels, by the Civil Engineering and Development Department of the Government of the HK SAR. To overcome the difficult ground conditions anticipated along the Contract 2 section of the project the tunnels will be constructed using mechanical and drill and blast (D&B) excavation techniques together with a 14.1m diameter multi-mode Earth Pressure Balance Tunnel Boring Machine (TBM). Land constraints imposed on the project alignment require that the final 500m section at the northern end of the Lung Shan tunnels, under Princess Hill (Figure 2), takes an almost 90 degree turn towards the north. The resulting 354m radius curve restricts the sight-line of road users to below the minimum 110m at 80km/hr hence, the internal span of the tunnels needs to be increased from 12.6m, in the standard straight section, to 15.4m in this curved section to accommodate a widened shoulder which will provide the required sight-line distance."

Jan 1, 2016

By Lottrey A. L, Sowerby B. D, Cutmore N. G

On-line monitoring of low rank coal quality during input to a process has the potential to provide benefits through: ò anticipation of coal quality variations prior to utilisation; ò provision of a tool to help determine the influence of coal quality on process behaviour, and ò provide a direct measure of coal quality for pricing. Moisture and ash are the two most significant coal quality parameters for combustion. They determine the energy content which can be derived from the coal and the problems arising from the presence of ash in the process (eg ash fouling, corrosion, erosion, particulate emissions and ash disposal). Extensive pilot-scale testing and full-scale experience has shown that specific coal/ash constituents (eg Na2O/ash ratio, acid-soluble aluminium, silica, sulphur contents, etc) are also important for the behaviour of Latrobe Valley brown coal during combustion, ash formation, deposition and removal of ash in precipitators and furnace ash hoppers. This paper discusses the range of on-line analysis techniques which have been investigated and their application to low rank coal analysis. Preliminary results from a joint SECV/CSIRO project which aims to develop two separate advanced instrument systems are also presented. These systems are based on: ò microwave attenuation and phase shift - for direct determination of moisture content; and ò inelastic neutron scattering - to provide total hydrogen, carbon, chlorine and ash contents, with potential for calculation of moisture content, specific energy, sodium content and Na20/ash ratio using correlations.

Jan 1, 1992

By G. Cavanough, A. Torrance

Emulsions have been developed for over forty years to become the most common water-resistant explosives used in the mining industry. An emulsion is a common commodity, with many examples in our day to day lives of one immiscible liquid dispersed in another. They have varying degrees of stability from a few seconds to years. What makes their application in explosives unique is twofold. They contain a high concentration of salts in the dispersed phase and also have a far larger volume of dispersed phase than continuous phase. The continuous phase contains at least 75% by weight of an oxidizer such as ammonium nitrate dissolved in water. The crystallization point of these solutions is often >60oC which means that the formation of the emulsion has to occur at an elevated temperature. Once the emulsion is cooled, its structure helps to prevent the formation of crystals in an otherwise unstable system. At room temperature there is a considerable potential for the small oxidizer droplets to crystallize which is countered by the strength of the oil layer and also the size of the emulsion droplet. If the emulsion droplet is too large then crystals can form which may lead to rapid deterioration of the emulsion and overall crystallization, accompanied by a temperature rise as the heat of crystallization is released from the emulsion. The size of the emulsion droplet is critical in preventing crystal growth and subsequent droplet coalescence and emulsion break down. One method of examining emulsions and understanding their structure is to use optical microscopy to measure droplet size and also emulsion deterioration from shearing, temperature cycling and when contaminants are introduced, such as detergents, different oil types, coating agents and dust particles. This paper reports on advanced techniques to quickly assess emulsion quality and stability

Jan 1, 2024