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By S Khadhraoui, T Yusuf, C Kirmse, E Hecker, R Degel, A Akouch, N Borowski, M Reuter

For an optimal design and control of metallurgical processes, a deep understanding of the thermodynamics of the governing reactions is required. Modelling the thermochemical behaviour of those reactions is complex, as it involves multi-component and multi-phase systems. For this purpose, thermodynamic computing systems such as FactSage™ (Bale et al, 2016), which combine Gibbs energy minimisation routines with large databases of optimised thermodynamic data of solutions and compounds, have been used within the SMS group GmbH. Recently, the successful integration of those thermodynamic computing systems into the digital platforms of SMS has been achieved through ChemApp, which made running complex thermochemical calculations in Python-integrated development environments possible. ChemApp is a programmer’s package for thermochemistry and incorporates the Gibbs energy minimiser of FactSage™ as reported by Petersen and Hack (2007) as well as by Zietsman and Petersen (2018). The digital platforms link the fundamental and the industrial aspects together and can be applied as a process advisor, or for the evaluation of the environmental footprint and the economic implications of different process routes, as discussed by Reuter (2023). Two examples illustrating the progress of the developments in this regard will be introduced: 1. The Tilting Refining Furnace (TRF) for copper scrap recycling and refining to anode copper (the BlueControlApp). 2. Dephosphorisation control for the oxygen steelmaking process (Basic Oxygen Furnace (BOF)).

Jun 19, 2024

By Duran A, Eggers M. J

It is standard practice in geotechnical studies for mine design to drill a series of inclined oriented boreholes into the proposed pit walls. However, this investigation tool is often used without an adequate understanding of the inherent shortcomings in the method and the many potential sources of error. Of the more commonly used orientation methods in Australia the clay imprint technique is probably the most reliable. Contoured stereographic plots of oriented core data are frequently characterised by diverse pole distributions and low concentration maximums compared with line mapping data. Common sources of error producing these poor results are misinterpretation of orientation marks or imprints, inaccurate marking of the reference line, errors in the structural measurement of the defects, lack of continuity information and blind zones sub-parallel to the borehole direction which correction methods frequently do not fix. Line mapping is the preferred method of structural data collection due to the lower overall cost, availability of continuity information and higher accuracy. The projectability of field mapping data to final wall positions can be assessed with a good understanding of the regional geology and local structural patterns. Where field mapping is not possible due to a thick regolith cover, core orientation should be carried out by experienced personnel to minimise the many potential errors.A series of case studies are presented which compare oriented core with mapping and highlight the inherent problems with the technique.

Jan 1, 1992

By Thomas Kuhn, Anna Wegorzewski

"INTRODUCTIONPolymetallic nodules from the Clarion and Clipperton Zone (CCZ) within the equatorial NE Pacific Ocean show high concentration of economic important strategic metals such as Ni, Cu, Co, Mo and Rare Earth Elements (REE). The content of those metals in nodules is depending on (i) the supply during individual growing periods, (ii) the environment conditions as well as (iii) on different manganese minerals, which occur in nodules. The incorporation of the metals can vary within the structure (incorporated into the structure / over vacancies of the structure) and this can be relevant for the further metallurgical treatment.Mineralogy of Mn-nodules from the CCZ and the incorporation of metalsManganese nodules consist of nm to µm thick layer growth structures (LGS) of different genetic origin (hydrogenetic/suboxic-diagenetic). Those LGS form due to the precipitation of Mn-and Fe-(oxy) hydroxide colloids from the oxygen rich near-bottom water and/or pore water (hydrogenetic growth; Halbach et al., 1988) or from suboxic (depleted in O2 <5µmol O2/l; Hein and Koschinsky 2013)) near-bottom water/pore water (suboxicdiagenetic growth; Halbach et al., 1988; Wegorzewski and Kuhn, 2014).In general, metals dissolved in seawater will be adsorbed and complexed on the oxide surfaces according to their different surface charge. The surface charge of the Mn-Fe (oxy) hydroxides depends on the pHzpc (zpc: zero point of charge). In seawater dissolved hydrated cations (Ni2+, Cu2+, Co2+) are adsorbed preferentially on the negatively charged Mn-oxide (MnO2 -) surface (pHzpc 2.8). In contrast, negatively and neutrally charged complexes (e.g., Ti(OH4); REE(CO3)2 -, MoO4 2-) are adsorbed on the surface of Fe-oxy hydroxide colloids (FeOOH+) which have a slightly positively charged surface (pHzpc 8.5; Stumm and Morgan, 1981; Koschinsky and Halbach 1995)."

Jan 1, 2017

By Lijuan Li, Zheng Lu, Xin Xia, Qijie Zhai, Qingchun Li

"Pulsed current and pulsed magnetic field have been applied to the bainite transformation of Cr5 steel. Three groups of experiments were conducted. In the first group, ordinary resistance furnace was used for heat treatment. The Cr5 specimens were rapidly heated up to austenitization temperature 940 °C, held for 20 min, air cooled to bainite transformation temperature 350 °C, held for 10, 20, or 40 min and then air cooled to room temperature. The second and the third group shared the same temperature-time curve with that of the first group, but their heat resources came from the Joule heat produced by pulsed current. 1.5 T pulsed magnetic field was exerted on the third group specimens when they were held at 350 °C, but the second group specimens did not undergo the treatment of magnetic field. It was found that both pulsed current and pulsed magnetic field obviously retarded the bainite transformation. The phenomena were discussed in terms ofliterature results.IntroductionApplying pulsed current and pulsed magnetic field technology are very pronnsmg ways to change the microstructure of materials by affecting the phase transformation process. People had found that pulsed current dramatically influences the behaviors of materials, for example, electromigration effect [l], the solidification of metals and alloys [2, 3], electroplasticity [4, 5], crystallization of amorphous alloys [6], healing of metal materials [7] and so on. As to pulsed magnetic field technology, a lot of effort had been spent on grain refinement in solidification of metals [8, 9], recrystallization of cold-worked metals and alloys [10] and Fe-based alloys solid-state phase transformation [11, 12]. Though application of pulsed current and pulsed magnetic field technology have proliferated in recent years, investigation on their effects on solid/solid phase transformation, especially bainite transformation, is lacking. The aim of this paper is to show the effects of pulsed current treatment (C-T) and the combined treatment of pulsed current and pulsed magnetic field (CM-T) on bainite transformation of commercial Cr5 steel"

Jan 1, 2014

By P. Christmann

The operational paradigm of mining industries is shifting from ?optimal profit for the financial stakeholders? to a new concept compatible with sustainable development ethics: ?maximize economic and social returns at the local, national and global levels, while avoiding negative environmental impacts?. The number of stakeholders concerned by mining companies has grown significantly over the last few decades, and the role of local communities and civil society is now acknowledged by the mining companies adhering to the sustainable development ethics. ?Involve me? is becoming a key to maximize the returns the mining industry can provide to sustainable development. As the world?s major importer of many mineral commodities, several coming from developing countries facing severe short-term problems, the European Union (EU) is an important stakeholder and has a responsibility in supporting actions to strengthen corporate and public governance capacities. The purpose of this paper is to highlight the drivers leading to the development of sustainability indicators and to propose, within the 6th European Framework Programme for Research, Technological Development and Demonstration Activities (FP6), an European-level initiative to develop sustainability indicators adapted to the mining industry and its population with relevant data.

Jan 1, 2003

By William Petruk

The Kidd Creek base metal deposit near Timmins, Ontario contains around 0.15 wt% Sn, mainly as cassiterite. The cassiterite occurs largely as inclusions in sphalerite, with 85% being in grains smaller than 18.5 micrometres in diameter. Concentrates and tails from the company&apos;s Cu, Pb and Zn circuits were studied to determine the liberations and recoveries of cassiterite in the products. The ore had been ground to about 65.% minus 44 micranetres in diameter (-325 mesh); 55% of the cassiterite was liberated. About 92% of the liberated cassiterite and 70% of the unliberated cassiterite were in the concentrator tails, and 20% of the unliberated cassiterite in the zinc concentrate. The company had attempted to recover the cassiterite from the concentrator tails by gravitational methods but recoveries were low. The grain size of the cassiterite in the gravity Sn concentrate was similar to the grain size of the liberated cassiterite in the concentrator tails. Research on flotation of the fine grained cassiterite from Kidd Creek ore has been conducted,

Jan 1, 1990

By D. Mills, W. J. Brantina

"Mechanical and magnetic characteristics of ferromagnetic materials were investigated by a pulsed ultra-sonic technique. Two instruments, the Ultrasonic Attenuation Comparator (Sperry) and the standard type Reflectoscope (Sperry) were used for measurements of the attenuation of the ultrasonic pulse. The effects of elastic tensile and compressive stresses on the attenuation of annealed and cold worked material are described. In addition, the effects of plastic de-formation, relaxation and aging processes and different ultrasonic test frequencies are reported. The results for Armco iron, SAE 1020 steel, SAE 4340 steel and AISI 420 stainless steel are shown. Under the test conditions, the attenuation was found to be largely a sum of two components; a ""dislocation"" component associated with the losses accompanying the oscillations of dislocation line segments and a ""ferromagnetic"" component associated with the microeddy currents generated by magnetic domain wall oscillations. Either of these components might be dominant depending on the nature of the particular specimen and the test conditions. Finally, the possibilities of using ultrasonics in residual stress determinations, in fatigue studies and in the study of the ductile-brittle transition in ferrous materials, are briefly discussed."

Jan 1, 1960

By Frances Hurd

WHEN 60:40 brass is heated to 825° C., given a drastic quench to obtain the beta solid solution, and reheated, various changes take place in the structure. Reheating at 200&apos; C. causes a fine, granular, sorbitic structure to appear which has been considered alpha solid solution. These particles coalesce at higher temperatures of reheating, and at 470° C., the alpha forms twins. A further study of these transformations was considered worth investigating.

Jan 1, 1927

By X. O. Xia

This paper introduces a kind of flotation machine for nonferrous metal, ferrous metal and non-metal minerals. With the application and development of flotation machine, researching the designment of master parts, including tank, impeller, stator, false bottom. Through the commercial run to validate the correctness of designment, achieving satisfied technical and economic target and supplying a kind of efficient and reliable flotation machine.

Jan 1, 2014

Professor N. S. Budavari holds a Dip!. Min. Eng. from the Technical University of Sopr on, Hungary, and a Ph.D. degree from the University of Newcastle-upon-Tyne, U.K. Mr J. J. Geldenhuys, Pr. Eng., is Divisional Manager Mining of Anglovaal Limited, being in charge of Prieska Copper Mines (Pty) Limited, Loraine Gold Mines, Limited, and Village Main Reef Gold Mining Company Limited.

Jan 1, 1983

By A. Bothma

The Impala No. 1A ventilation shaft is located approximately 15 kms north of Rustenburg and is accessed via the R510road from Rustenburg to Northam/Thabazimbi. This situation is shown on the location plan in Figure 1. The geology at the site consists of an upper layer of black turf of about 1 metre in thickness, grading into weathered norite. The depth of weathering is generally less than 5 metres. Zones of deeper weathering may occur along fracture zones associated with faults and dykes. Groundwater occurs mainly within the weathered/fractured aquifer system. The ventilation shaft is a 5.1 m diameter upcast shaft ,and forms part of a system of ventilation shafts to complement the existing infrastructure as mining progresses down the new twin decline extension of Impala 1 shaft. The principal reason for these shafts is to lessen the risk of an extended RAW and also to counter the effects of the heat build-up as the mining goes deeper, with the resultant effect that the existing cooling centre (fridge plant) becomes more remote from activities. The No. 1A shaft (upcast) is positioned approximately 1,2 km on down dip from the main shaft and the No. 1Bshaft (downcast) approximately 1,2 km further. Geological information was used from a borehole 1,2 km away on strike from the upcast shaft. The first shaft (1A) is a 5,1 m diameter hole to be fitted with two 2,2 MW fans, whilst the second shaft (1B) is 4,1 m diameter to accommodate a 7MW fridge plant.

Jan 1, 2001

By Lee Ann Gardner

This U.S. Bureau of Mines publication presents a case study of the processes used in permitting the Nome Offshore Placer Project, a gold mining project offshore Nome, Alaska which operated from 1985 through 1990. The mining project, developed by Western Gold Exploration and Mining Company, Limited Partnership (WestGold), used the BIMA, which was at the time the largest bucketline mining vessel in the world, to dredge gold from the ocean floor. This case study reviews the permitting process from the regulators&apos; and industry&apos;s perspectives, as well as characterizing the efficiencies and inefficiencies associated with this case. The Federal, State and local laws applicable to the Nome Offshore Placer Project are identified, agency jurisdiction and interagency relationships are explored, and the chronology of the permitting process is examined. The regulatory authorities for both environmental monitoring and post-mining monitoring are delineated. Significant milestones affecting the project and required regulatory submittals are also included. The case study of the Nome Offshore Placer Project is detailed with respect to agency involvement and coordination, approaches to permitting from both the regulators&apos; and developer&apos;s perspective, environmental issues, and permit stipulations which were unique to the project. The advantages and disadvantages of these topics are discussed.

Jan 1, 1992

By K. Sasaki, H. Miyakoshi, K. Mashiba

A ventilation analytical system adapting nodal pressure method using skyline modified Choleski&apos;s decomposition scheme for network-flow analysis and a new practical system to estimate various thermal air conditions has been developed. The quasi-linear equations for solving steady-state network airflow have been described using the connective function in general forms. The skyline modified decomposition scheme has an advantage on rapid convergence and the sake of computer memory space com- pared with other schemes. The key part of the analysis for climatic conditions through network airways is how to estimate the temperature of the airway rock-surface with partly or full wet condition. A practical and simple solution without any iterative calculations for its estimation has been proposed. This new solution is applicable to practical ranges of airflow temperature, humidity, rock thermal properties and wetness. The present analytical sys- tem have been successfully applied to a ventilation simulator named "M1VENA"developed by authors.

Jan 1, 1996

By J Petrolito

"To improve the economic and environmental performance of underground mining operations, it is common practice to return the metallurgical waste material underground as backfill. This is called hydraulic backfill and is used to fill the mined-out areas not exposed to further mining. To provide mechanical support for underground mining a cemented backfill is normally used. Since its introduction, cemented backfill has allowed mining companies to increase their ore extraction and improve working and environmental conditions. However, cemented backfill represents up to 50% to 85% of the mine’s operating cost compared with 5% to 10% for hydraulic backfill.These economic pressures have led mining companies to carry out research into the partial or total replacement of cement using a variety of alternative materials. The materials are generally site-specific materials, readily available, and cost-effective relative to cement. Such investigations have led to reduced cost of many backfill mixes while maintaining, and in some cases improving, the physical properties of cemented backfill. However, in most cases, cement still remains an integral part of any binder combination. This can be attributed to the alternative binders investigated being either non-binding materials or capable of generating only low-strength backfills, except when used in conjunction with cement.This paper provides a historical review of backfilling binder materials and their characteristics. In particular, it reviews the many alternative materials that have been proposed to either partially or fully replace Portland cement as the main binder."

Jan 1, 2005

By J. F. Myers, F. M. Lewis

IN the mining and handling of sulphide ores, some degree of oxidation takes place on the sulphide surfaces, which are exposed to the atmosphere. It is, moreover, well known that the oxidation compounds formed are a factor when such ores are subsequently treated by flotation. Modern operating technique and reagents are capable of contending with this condition to a major degree, provided that the proportions of the reagents used are varied correctly. This is particularly true at the Tennessee Copper Co., where the ore treated contains pyrrhotite in addition to other sulphides. A number of soluble salts, some of which are unstable, can be formed during the oxidation of the sulphide ores. Those unstable salts, whose oxygen requirements are unsatisfied, are constantly changing to more stable forms because oxygen reacts with them during the crushing, grinding and other operations of ore preparation. We add no chemicals of any kind to the ore pulp in its preparation for flotation feed. Consequently the only compounds that are present in the flotation feed are those produced by the natural oxidation of the ore in the presence of air and water. The Tennessee Copper Co. ore is composed of from 60 to 70 per cent sulphides and from 40 to 30 per cent nonsulphide material. It is not the purpose of this paper to discuss the nature of these various oxygensulphur compounds nor their effect on flotation, but to describe a method for [ ] correcting the effect. Suffice it to say that we have found that the reducing sulphur and oxygen salts have a depressing action on our bulk flotation process.1 From long experience we find that the best means of correcting for this variation in our work is to increase or decrease the quantity of xanthate, the promoting agent, as the quantity of the reducing salts increases or decreases. It was, therefore, very desirable to provide the operators with some quick and

Jan 1, 1946

By Marcus Grossmann

THIS paper offers for consideration certain somewhat radical modifications in the iron-carbon diagram, these modifications being the result of the presence of notable amounts of alloying elements. When only small amounts of alloys are present, &apos;the standard iron-carbon diagram (Fig. 1) can be used with but insignificant changes; when larger amounts of Chromium, Per Cent FIG. 1.-IRON-CARBON DIAGRAM. FIG. 2.-IRON-CHROMIUM DIAGRAM. alloys are present, however, it assumes a distinctly altered appearance. No comment is offered for the present except to call attention to the delta area, A4BM, which represents a region of mixtures of austenite and delta iron, just as area A3SP represents mixtures of austenite and alpha iron.

Jan 12, 1926

By Z. Konstantinovic, M. Ahrens

Due to the large installed electrical power and the large number of electric drives in minerals and mining plants power factor compensation and harmonic filtering has always been an important issue. For the design of harmonic filter and power factor compensation installations several approaches can be taken. The paper describes different concepts and their advantages and analyzes special requirements and design considerations for minerals and mining plants. It also highlights areas where problems can occur and which points need to be addressed carefully. Optimized designs and solutions are discussed in case studies and the resulting energy savings and benefits for the plant operation are shown.

Jan 1, 2007

By Markus A. Reuter, Joep Verwoerd, Marc J. A. Pijnenborg, Yongxiang Yang

"Incineration is a proven disposal technology for all waste materials with heat release potentials, and provides high degree of toxic destruction and control for a broad range of hazardous materials. In the Netherlands, all the hazardous wastes are processed at AVR-Chemie located at the Rotterdam harbour, through rotary kiln incinerators. The newly enforced regulations from the European Union with stricter emission levels require a better understanding of the incineration process and improved process control. However, the transport phenomena and combustion processes within the kiln system are very complex and not well understood. In order to get better understanding of the incineration process, research has been carried out to study the fluid flow and combustion behaviour of the incineration system. Computational Fluid-dynamics (CFD) was used to simulate the gas flow and waste combustion process, and temperature measurements of the operating rotary kiln incinerator were conducted to validate the CFD model. This paper will present the latest results from the current research project for simulating gas flow and combustion heat transfer for a wide range of hazardous waste streams.The simulation of the waste incineration process was carried out using a general-purpose CFD code Phoenics. The rotary kiln and the secondary combustion chamber (SCC), with a waste processing capacity of 50,000 ton/y and an energy input of 30 – 40 MW, is translated into a CFD model. The model includes a k-e turbulence model and a global gas-phase combustion model (3-gas or 7-gas combustion model). The 3- gas model (Simple Chemically-Reacting System, SCRS) predicts only the thermal effect of the fuel combustion, and only one global fuel is used, therefore, real chemical species are not taken into account. In the 7-gas combustion model, (an Extended SCRS, ESCRS), different forms of waste fed into the incinerator have been modelled into a mixture of a general hydrocarbon fuel C3H4 and other components such as CO, CO2 and H2O. Thus, all the incoming fuel streams with different compositions and calorific values can be properly converted into separate inlets. The combustion of the waste is assumed to take place only in gas phase in two steps: (1) primary combustion of the main fuel component C3H4 to form CO and H2, (2) secondary combustion of CO and H2O to form CO2 and H2O. The rate of each combustion reaction is assumed to be controlled by turbulent mixing of fuel and oxidant (air or oxygen), i.e. the Eddy-Break-up (EBU) model. The resulted temperature field was validated with temperature measurement data, and the simulated temperature distribution from both 3-gas and 7-gas model have reasonable agreement with the measured data."

Jan 1, 2003

By M. T. Ityokumbul

The liquid phase mixing in Western Research Centre (WRC) pilot plant flotation column with diameter of 0.76 m has been characterized using a salt tracer. The process variables studied were gas and liquid flow rates. The response of the column to a tracer pulse input was monitored at three axial and two radial locations. For all the experimental conditions investigated in the present study, radial and axial concentration gradients were not observed. It is thus concluded that the 2 tph flotation column is behaving as a well mixed tank. This finding is consistent with the observed poor recoveries of coarse fractions in the column flotation circuit. Based on the findings of this report, it is recommended that several schemes of reducing the backmixing be implemented and evaluated for their effectiveness in improving the column recoveries.

Jan 1, 1994

During development mining, ventilation capacity may decrease and the ventilation requirements may depart from initially planned values depending on the mining rate, increases in the methane emission rate, and changes in ventilation airway leakages. Insufficient ventilation air quantities and the occurrences of high methane liberation rates can overwhelm the existing quantity of ventilation air and result in elevated levels of methane gas during development mining. This condition can both limit the development of that section and increase the risk for an ignition that may lead to an explosion. Thus, the prediction of ventilation air requirements prior to mining can enhance worker safety by reducing the likelihood that explosive methane-air mixtures form. This study presents an approach for prediction of methane inflow rates using coalbed methane reservoir modeling. For this purpose, a two-phase coalbed reservoir model of a three-entry type roadway is developed. In the model, grids are dynamically controlled to simulate development of entries. Examples are given for methane inflow and ventilation air requirements as a function of mining rate, development section length, mining height, and the existence of degasification boreholes. This technology can be used to limit the methane concentrations occurring as a result of the influences of various coalbed and operational parameters.

Jan 1, 2008