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By Noel A. Warner

Modern steelmaking is based on direct use of oxygen in high intensity batch reactors. A totally new approach is proposed in this paper, based on the view that pursuit of high intensity is unlikely to lead to successful coal-based continuous steelmaking. By substituting carbon dioxide and water vapor as the oxidants rather than using oxygen directly, the intensity is greatly reduced. Accordingly, subsurface formation of carbon monoxide bubbles can be avoided by careful manipulation of the three participating rate processes, gaseous diffusion, interfacial chemical kinetics and liquid phase mass transfer. Steelmaking can then be carried out without explosive ejection of molten droplets and the generation of micro-spray but rather in a controlled and fume less fashion. The vital component is the introduction of generic melt circulation technology. Three melt circulation loops in series are envisaged. Starting with a composite feed of iron ore fines, pulverized coal and lime flux, a metallized solid raft floating on molten iron is propelled out of the ironmaking loop onto the first of two downstream steelmaking loops. In the first, a liquid slag is formed, primary decarburization is undertaken not with oxygen but rather with CO2 and H2O and the melt is desulfurized. The semi-product stream enters the third melt circulation loop, where open-channel decarburization is effected along with dephosphorization to yield a low carbon steel product. Alternatively, the melt leaves the last loop to irrigate a packed tower countercurrent to argon at around 100 mbar to continuously produce ultra-low carbon (ULC) steel.

Jan 1, 2003

By Noel A. Warner

Modern steelmaking is based on direct use of oxygen in high intensity batch reactors. A totally new approach is proposed in this paper, based on the view that pursuit of high intensity is unlikely to lead to successful coal-based continuous steelmaking. By substituting carbon dioxide and water vapor as the oxidants rather than using oxygen directly, the intensity is greatly reduced. Accordingly. subsurface formation of carbon monoxide bubbles can be avoided by careful manipulation of the three participating rate processes, gaseous diffusion, interfacial chemical kinetics and liquid phase mass transfer. Steelmaking can then be carried out without explosive ejection of molten droplets and the generation of micro-spray but rather in a controlled and fumeless fashion. The vital component is the introduction of generic melt circulation technology. Three melt circulation loops in series are envisaged. Starting with a composite feed of iron ore fines, pulverized coal and lime flux, a metallized solid raft floating on molten iron is propelled out of the ironmaking loop onto the first of two downstream steelmaking loops. In the first, a liquid slag is formed, primary decarburization is undertaken not with oxygen but rather with CO2 and H2O and the melt is desulfurized. The semi-product stream enters the third melt circulation loop, where open-channel decarburization is effected along with dephosphorization to yield a low carbon steel product. Alternatively, the melt leaves the last loop to irrigate a packed tower countercurrent to argon at around 100 mbar to continuously produce ultra-low carbon (ULC) steel.

Jan 1, 2003

By V. A. Chanturiya, T. N. Matveeva, N. K. Gromova, T. A. Ivanova

"The research is aimed at solving the problem of increasing the extraction of gold from refractory ores, which are the main source of growth in gold production in the next decades. The purpose of the research is the development and scientific substantiation of the reagent modes for flotation extracting of gold from refractory ores using eco-friendly low-cost herbal modifiers (HM), providing increase in gold recovery and quality of gold concentrates. In the course of research laboratory techniques for the preparation of experimental samples of HM were developed, which included the sequence of operations of grinding Heraclium leaves and stems grinding, 2-stages extraction at a temperature of 50-60 °C, short-term ultrasonic treatment, filtration and subsequent unification of extracts. According to the developed method, the experimental samples of HM and conducted research were tested to analyze their sorption and flotation activity related to the extraction of gold from refractory gold ores.New data on adsorption and flotation properties of Heraclium stems and leaves extracts (HSE) in selective flotation of Au-sulfide minerals were obtained using UV-spectroscopy, scanning electronic and laser microscopy and atomic force microscopy. The dimensions and shapes of adsorbed hydrophilic films of herbal reagents were identified and mechanism of formation of stable insoluble compounds on the surface of minerals in flotation was explained.Research flotation tests carried out on samples of refractory gold ore of one of Russia deposits showed the possibility of effective use of herbal modifiers to improve qualitative and quantitative indicators of enrichment compared with the standard reagent regime. New reagent modes, using herbal modifiers in an amount of 5 to 10 ml of the extract (300 - 600 g / t, respectively) improves the quality of the concentrate: gold content attains 14.7 g / t, 1.34 times higher than in the baseline experiment and provides a gain of 3.13% extraction.The developed reagent regime with herbal modifiers is the author's original design, patented (patent of the Russian Federation) and have no analogues in the world of mineral processing. (Application number 2015116125 from 04.28.2015, ""The method of flotation separation of sulfide minerals using herbal modifier"", Russia). Actual application of new plant extracts as modifiers in flotation of sulfide minerals is the possibility of replacing of highly toxic chemical compounds by environmentally safe substances of plant origin. Implementation of the developed methods of extracting gold from refractory minerals with herbal modifiers will help to improve gold recovery at 3-5% and the quality concentrate of not less than 1.2 times, leading to higher productivity and a reduction of the negative man-made effects on the environment ."

Jan 1, 2016

By Matveyeva Tamara

The main deposits of gold-sulfide ores of Russia are characterized as refractory raw material with the non-uniform finely-interspersed sulfide mineralization, submicron gold, the low gold content (3-5 ppm) and non-uniform distribution of the gold associated with pyrite and arsenopyrite. These ores show low indicators of extraction of gold and silver at cyanidation. Flotation is one of the basic technological procedures of processing of gold sulfide ores however simultaneous presence of pyrite and arsenopyrite and lack of effective methods of their selection constrains application possibility of flotation schemes because of rigid requirements to flotation concentrates under the arsenic content and practically excludes smelting of pyrite concentrate. The main losses of precious metals at flotation technologically are concentrated in thin classes (up to 15 %) demonstrating an inefficiency of standard reagent modes. For an estimation of expediency and possibility of application of selective flotation of pyrite and arsenopyrite a scientific substantiation of the mechanism and criteria of selection of gold-bearing ferrous sulfides of various material structure is developed and for difficultly divided pairs of sulfides with close technological properties the new selective reagents providing effective extraction of gold from hard-to-beneficiate ores are designed. The original technique for modifying surface composition of natural sulfides by nano-sized Au is worked out and the mechanism of selective adsorption of new reagents ? oxypropyl ester of diethyl-dithiocarbamatic acid (OPDTC) and oak bark extract (OBE) on Au-bearing sulfide minerals is revealed. Formation of almost insoluble OPDTC-Au compounds is defined by methods of scanning electronic microscopy (SEM) and UV-spectroscopy. Application of developed reagent modes using new reagents have been tested in laboratory conditions at flotation gold-sulfide ores samples and collective concentrate probes providing high extraction of gold and improved quality of the concentrate (less than 2 % As). Keywords: pyrite, arsenopyrite, selective flotation, flotation reagents adsorption, complex-forming, gold recovery.

Sep 1, 2012

By Y. Nakahiro, T. Wakamatsu, M. S. Elsalmawy

The flotation of quartz, feldspar and alumina was studied as a function of pH when using N-alkyldiamines as collectors. The lengths of alkyl chains of diamines were 8, 9, 10, and 12 carbon atoms. It was found that shorter hydrocarbon chain length of alkyldiamines has stronger tendency to float quartz while the feldspar responded poorly to flotation with these collectors at high pH values. The effect of addition of nonionic surfactant of Brij type, when using dodecadiamine as collector, was investigated. Flotation studies in the absence and in the presence of sodium dodecylsulfonate were carried out. These studies have indicated that sodium dodecylsulfonate, in the concentration studied, functions as strong depressant for feldspar.

Jan 1, 1995

By T Walsh, S R. Mudnuru

The development of lithium-ion batteries, coupled with the global trend towards electrification of transportation, has led to a dramatic increase in the demand for lithium. The production of lithium from hard rock ores is increasing, and flotation has proved to be an effective means for the beneficiation of many pegmatitic lithium ores. Clariant Mining Solutions has developed a range of novel collectors for the flotation of spodumene and other lithium ores, and this paper presents examples of some of the most recent developments. Fatty acids are the typical collectors for lithium flotation, however the grade and recovery achieved with these collectors is often below the desired level. There are also some significant drawbacks associated with the use of fatty acid collectors, such as the formation of calcium soaps which give rise to filtration problems and the need for acid washing. Several FLOTINOR products have been developed as alternatives to fatty acids. These products offer equivalent or better metallurgical performance at significantly lower dosages than fatty acids. This offers benefits to the flotation circuit as well as potentially reducing the issues associated with downstream processing of the concentrate.

Aug 24, 2022

By A. R. Javadi

Pyrite (FeS2), chalcopyrite (CuFeS2), sphalerite (ZnS) and galena (PbS) generate hydrogen peroxide (H2O2) when placed in water, with pyrite generating the most amount of H2O2. The order of these minerals for generating H2O2 in water is: pyrite > chalcopyrite > sphalerite > galena. In previous research, the methods of generation of H2O2 in the grinding mill were studied. In this study, data from experiments were included by using MODDE 9 software for six parameters composed of water, grinding media, particle size; adding collector to the grinding, and adding depressant and pH. Finally the optimal condition was achieved. According to the results, most of the recovery is related to the particle 75 μ size and when using processed water, adding 100% collector and without depressant and pH 10. The most recovery of lead in the case of the use of fresh water is in the case of 100% collector, without depressant, pH 10 and 150 μ particle size. Maximum recovery in fraction size 45 μ in the case of water process is 100% collector, without depressant and pH 10. Maximum depressant of pyrite will be the fraction size 75 μ, distilled water, without collector, 100 depressant. Keywords: Sulfide mineral, hydrogen peroxide, flotation, oxidation

Jan 1, 2020

By Allan M. Hale

The central Florida phosphate industry is not a recent development. The first phosphate mining occurred in approximately 1888 (1). Many of the original mining companies were "wildcat" operations operated with rapid phosphate extraction as the sole purpose and no long-term commitment to development. Many of the early pioneers were ill-equipped to mine phosphate at either a practical or economical level; as a result many of these early companies "folded" after only a brief period of operation. However, as these early companies went out of business, several large companies developed, expanded their mining territories bought up the folding companies and by 1903 (little more than 10 years after the first mines were started), approximately 37 of the original 60 mines were control- led by three major companies (1). In the early period, mining reclamation was nonexistent. The mined out areas were left to revegetate and reclaim "naturally" over the period of many years. Reclamation practices were only started relatively recently and the various reclamation techniques developed and used in the past have continued to be employed with varying degrees of success through the present time. The reclamation techniques used in the past and currently include land and lakes restoration, sand tailing reclamation, slime ponds reclamation and overburden fill.

Jan 1, 1980

By S. O. ANDROS

RECORDS in mining operations naturally fall when improved equipment and methods are developed. And tunneling through the Continental Divide is a mining operation, even though the tunnel was not driven to strike a vein at depth. Although many engineering feats have been successfully accomplished in the development of water supplies in the Western States, the Twin Lakes Tunnel in Colorado presents some unusual features that make it noteworthy. To begin with, it is the first trans-mountain water diversion project in the West. The fact that the Continental Divide intervenes between where the water is and where it is needed was brushed, aside as of minor importance. It was enough to know that on the western side of Independence Pass, the highest in Colorado, with an elevation of 12,095 ft., there was water which was needed on the eastern side, where the Twin Lakes are situated, forming the

Jan 1, 1934

By I Canbulat, J Oh, A Mcquillan, D Payne

This paper presents a new risk assessment tool for coal mine excavated slopes. This new empirical-statistical Slope Stability Assessment Methodology (SSAM) is intended for use by geotechnical engineers at both the design review and operational stages of a mine’s life to categorise the risk of an excavated coal mine slope. A likelihood of failure is determined using a new slope stability classification system for excavated coal mine slopes developed using a database of 119 intact and failed case studies sourced from open cut coal mines in Australia. Consequence of failure is based on slope height and stand-off distance at the toe of the excavated slope. Results are presented in a new risk matrix, with slope risk being divided into low, medium and high categories. The SSAM is put forward as a new risk assessment tool to assess the potential for, and consequence of, excavated coal mine slope failure. Unlike existing classification systems, assumptions about the likely failure mode or mechanism are not required. Instead, the SSAM applies an approach which compares the conditions present within the excavated slope face, with the known past performance of slopes with similar geotechnical and geometrical conditions, to estimate the slope’s propensity for failure. The SSAM is novel in that it considers the depositional history of strata in an excavated slope and how this sequence affects slope stability. It is further novel in that it does not require explicit measurements of intact rock, rock mass and/or defect strength to rapidly calculate a slope’s likelihood of failure and overall risk. Ratings can be determined entirely from visual observations of the excavated slope face. The new SSAM is designed to be used in conjunction with existing slope stability assessment tools. CITATION:Mcquillan, A, Canbulat, I, Payne, D and Oh, J, 2018. New risk assessment method for coal mine excavated slopes, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 473–495 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By Vitor Guarnier Domiciano

The need to adjust the monolithic refractories to increasingly severe and unstable Blast Furnace casthouse operating conditions has been a major challenge for refractory suppliers in order to guarantee the runner’s safety and its availability for operation. This paper presents the properties of a new robust single line Al2O3-SiC-C refractory castable developed to endure the severe operating conditions that main runners are facing in today's Blast Furnace casthouse scenario. Practical results during almost one year of testing revealed a significant lower wear speed of the new refractory lining when compared to a standard product.

Aug 1, 2018

By F. J. Macias, A. Bruland, F. E. Dahl

"Tunnelling by use of Tunnel Boring Machine (TBM) is gaining a greater presence as a suitable excavation method. Disc cutter consumption has a strong influence on performance and cost when using TBMs and the influence becomes even more relevant in hard rock. Furthermore, good predictions of TBM performance and cost facilitate the control of risk as well as avoiding delays and budget overruns. Since abrasive wear is the most common process affecting cutter consumption, good laboratory assessments are needed. A new abrasivity test method called Rolling Indentation Abrasion Test was developed. The goal of the new test design and procedure is to reproduce wear behaviour on hard rock tunnel boring in a more realistic way than traditionally used methods by introducing wear by rolling contact on intact rock samples. INTRODUCTIONHigh investments are involved in the tunnelling industry, especially in Tunnel Boring Machines (TBMs) projects. Performance predictions and cost estimations are crucial for planning and risk management of TBM projects. Cutter consumption has a large influence in terms of time and cost, and an even greater effect in case of hard rock projects. Many factors are influencing the amount of cutters consumed in hard rock TBMs. Normal TBM operation results mainly in abrasive wear on the cutters and appropriate methods for abrasivity assessment are needed. Rock abrasiveness cannot be considered as an intrinsic property and the complete tribological system should be considered in addition to the geological properties of the rock.In the present paper, a new test method for abrasivity assessment in tunnel boring called Rolling Indentation Abrasion Test (RIAT) is presented. The traditionally used test methods for determination of rock abrasiveness uses sliding or impact contact in order to cause wear while the RIAT introduces rolling contact on intact rock samples. The ambition of the new test device is to have a reliable method to evaluate the cutter wear in hard rock tunnel boring by reproducing wear behaviour on rolling disc cutters in a more realistic way. It has been established by many authors that the abrasion of a cutter ring is proportional to its rolling distance (Rostami, 1997; Bruland, 1998). In the present work, the weight loss of a mini-cutter ring is measured subsequent to testing in order to evaluate wear in the rolling process and could hence be related to cutter ring wear. Indentation of the tools in the intact rock sample is considered as an indication of the surface hardness of the rock or the resistance to indentation by rolling."

Jan 1, 2015

By Matteo Tomba

Today’s steel market is characterised by high competitiveness and tight profit margins; therefore, the operational costs of rolling mills must be as low as possible, while ensuring a final product of the highest quality standards. PERT SRL is an engineering company with a long-term experience in the international steel market, specialised in the design and supply of highly innovative and bespoke solutions for siderurgical and environmental plants. Because of its strong commitment to deliver excellent products and services, and its ability to innovate and adapt to the fastchanging market requirements, PERT has studied a new generation of BI-SUPPORT rolling stands, designed to be used in rolling mill plants for the production of rebars, rounds and sections in special quality bars (SBQ) steel grade, wire rod, light and medium section, suitable also for special steel plants. This paper will provide a deep insight into the key technical and economic features that have revolutionised the rolling technology for long products, such as the absence of spindles and piping on board, the considerably reduced number of spare parts required, a ring gap regulation system, and the compact dimensions, which lead to significant savings in investments and production costs; at the same time, the BI-SUPPORT stands guarantee excellent standards to the final product, an increase in plant productivity and a general improvement in the plant management.

Aug 16, 2017

Rosebery Mine is situated on the west coast of Tasmania and is AustraliaÆs largest volcanic-hosted base and precious metals deposit (zinc, lead, copper, gold and silver). The milling operation has been producing zinc, lead and copper concentrates continuously for over 100 years. RoseberyÆs long life demonstrates the operation to be high grade, and high margin, capable of operating through several commodity price cycles. Paradoxically, throughout this long history the ælife-of-mineÆ as defined by proven and probable reserves has been short. Zinifex has demonstrated its commitment to discover the future of Rosebery with the growth project æProject HorizonsÆ. The aim of the project is to extend the life of mine beyond 2020, with an additional exploration expenditure of $19 million over three years. Despite the maturity of the deposit, early success has confirmed the potential with the discovery of new resources. Mine planning strategic studies are challenging established paradigms of mine production, throughput rates and metal cut-off grades. Discovering the optimal process rate for Rosebery, by examining the æHill of ValueÆ and underground mine optimisation is proving critical to the best exploitation of RoseberyÆs rich resources. The promise of finding a mine within a mine is being realised, with new lenses being delivered by exploration success and real grade/tonnage options optimised through dynamic mine planning. The future of Rosebery is co-dependent on these two areas of discovery. This ensures capital expenditure decisions are informed, to secure the next 20 years of wealth creation and beyond.

Jan 1, 2008

Reduce injuries caused by slips and falls from large haulage vehicles. Approach Replace the flexible-cable or chain-type lower ladder steps, with steps that extend closer to the ground and do not sway when stepped on. Modify dimensions of entire ladder to new industry recommendations. How It Works New lower ladder steps are supported by side pieces made of pretensioned, solid-wound, coil springs fabricated from high strength steel. Unlike conventional crash-resistant steps, which flex or swing freely when stepped on, the spring supported steps can maintain the same inclination as the fixed upper portion of the ladder while supporting an average-weight operator. The steps are also highly resistant to collision damage because they yield on impact if rammed into obstructions such as rocks or berms. See photograph.

Jan 1, 1980

By Jesús V. Saccsa, Kenji B. Loayza, Erick M. Condori, Jorge A. Velásquez

This research investigates how to reduce manufacturing costs of a safety fuse composed of black powder, replacing its ingredient NO3K by NO3Na for processing, and contributing to minimize costs per blasting.

Jan 1, 2017

The optimisation of a mining operation requires precise ore grade control, metallurgical accounting, and laboratory sampling protocols, which are implemented by using accurate and flawless sampling systems. Good sampling practices, and sampling technologies in these fields have been historically poor and too many existing sampling systems available on the market are flawed in many ways. This is mainly the result of a poor understanding of the Sampling Theory, and the natural result of international standards on sampling that fail to present the Sampling Theory in a logical way, that still promote non-probabilistic sampling, and that fail to address the important details that make a correct sampling system. Many standards barely mention the Sampling Theory in appendices when it should be clearly the main body of a reliable standard on sampling. As a result, many standards show only little expertise in the Sampling Theory. Conventional statistics should only be a scientific tool for the Sampling Theory to reach its height, which has always been well understood by its creators. Conventional statistics can indeed be addressed in appendices of standards in sampling, but not the other way around. Until the Sampling Theory is recognised as the main body of a standard on sampling, incorrect sampling technologies will plague the market, and make it impossible for mining operations to optimise their mining and metallurgical processes. This paper makes a short list of correct new sampling technologies that have been created with respect to the principles taught in the Sampling Theory. Also, suggestions are presented to create better international standards on sampling, which would provide a stronger incentive for manufacturers to build correct sampling systems, and for engineering firms to install only sampling systems that respect the rules of sampling correctness listed in the Sampling Theory.

Jan 1, 2004

"INTRODUCTION Secondary mine ventilation has been hamstrung by the availability of fans that satisfy many competing operational factors. The sometimes legislated requirement of adequate volume to the working face, the minimisation of excavation required to fit the selected secondary fan and the power requirements of various operational phases has, in the past, not been satisfied with just one system. The new system being introduced overcomes all these competing requirements in one simple unit with an added bonus of being very durable without loss of performance when wear occurs on the impeller. Existing Operational Situation Several studies (e.g., CIPEC, 2005; LCG Energy Management Group, 2009) have found that between 42% and 49% of mining energy costs are associated with mine ventilation, depending on the type of mine and the equipment used. If we then look at the general breakdown of installed power of the secondary fan to primary vent fans, the ratio is around 2:1. Thus the total energy costs of the secondary ventilation represents about 25% of the overall mining energy costs. It is of interest to note that the cost of running a typical two stage axial vs the cost of purchasing and general maintenance cost of the same fan over a 10 year period, the breakdown will be conservatively in the order of 40:1.The currently available secondary ventilation axial fan have one duty curve at any given time. Generally this can be changed manually within the motor power parameters but requires a minor outage and removal of the fan to do the pitch adjustments. As the bag vent ducts grow longer, the supplied air reduces to a point where inadequate air is supplied to the working face. This is exacerbated by underground equipment putting additional resistance in the heading and further reducing the supplied air at the working face. This shortfall is normally corrected by the installation of an additional fan in the system to overcome losses in the bag system but comes at a cost of production as the heading needs to be shutdown to install the second fan. This also means that the heading is supplied with excessive air on the shorter runs with a wastage of fan power."

Jan 1, 2019

By J. Dubinski

Poland is the ninth largest coal producer in the world and Coal Company is the largest Polish producer of this deposit yielding 51% of national production. Coal Company mines are located in the Upper Silesian Coal Basin. These are underground mines which operate in difficult geological conditions at great depths of up to 1200 m. One of the most common natural hazards in Polish mines are rockburst and seismic hazard impacting on surface infrastructure and habitants. In the assessment of the rockburst and seismic hazard methods of mining seismology play a leading role. This paper presents progress that was achieved in the last few years in the implementation of new seismic monitoring systems and seismic interpretation methods for the prevention of hazard deriving from seismicity induced by mining. This progress in assessment of rockburst hazard and impact of seismic activity on the surface infrastructure was achieved through close cooperation between the Coal Company and Central Mining Institute ? the country?s leading scientific institute in the field of mining seismology. New theoretical solutions are in the process of testing in mines of Coal Company where seismic monitoring systems are installed and controlled by well-qualified personnel. Some directions of further joint actions to increase the effectiveness of rockburst and seismic hazard assessment are presented as well.

Aug 1, 2013

By Robert R. Grinstead

Two new ion exchange resins have been developed, which selectively absorb copper and nickel in preference to ferric iron from dilute sulfuric acid solutions of pH 1-3. The first absorbs copper and not nickel and can be readily eluted with 1-2N sulfuric acid. This resin is well adapted to the processing of copper leach liquors, including relatively low grade liquors obtained from dump leaching. The second resin absorbs nickel as well as copper in the same pH region, but only the nickel is eluted with 1-2N sulfuric acid. Elution of the copper requires much stronger (ca. ION) acid, altho both species are readily eluted with dilute (ca. lN) ammonium hydroxide. This resin, which should be useful in processing of certain types of copper-bearing solutions, may also be suitable for treating acidic nickel leach solutions of laterites and other non-sulfide ores.

Jan 1, 1976