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By R. Boom, J. Halder, B. Snoeijer, B. Deo, A. Overbosch

Operational data of BOF and the slag samples for different starting conditions of phosphorus(0.06–0.26 per cent P) and silicon content (0.3–1.2 per cent Si) of hot metal have been analysed. The contribution of parameters that are well known to affect phosphorus distribution at tap, like basicity, temperature, FeO content of slag, slag mass etc., is investigated through the models of ionic theory of slag, optical basicity, regular solution approach and molecular theory of slag. The best overall results are obtained by the model based on molecular theory of slag in which several operational parameters are also incorporated. The investigations of different slag samples, based on optical, SEM, EPMA and X-ray studies, reveal the effect of MgO and Al2O3on slag morphology and phosphorus distribution in different phases. It is important to consider phosphorus distribution ratio in the solid and liquid part of slag. The solid part of slag, which is mostly dicalciumsilicate, can contain up to 5 per cent phosphorus. The phosphorus content of the liquid part of slag may depend upon the phosphorus content of hot metal or phosphorus load of slag. It is found that incorporation of effect of dicalciumsilicate in the model improves the accuracy of prediction. For better process control, the addition of iron ore towards the end of blow must be avoided while treating high phosphorus hot metal or during the production of ultra low phosphorus steels. Keywords: steelmaking, BOF, phosphorus distribution, slag morphology, MgO, Al2O3,dicalciumsilicate, process control, models

Jan 1, 2004

By M Quinteiro, Å Sundqvist

What is special about being a female mine manager? We do not believe that the challenge is greater for women in managing a mine compared to managerial positions in other male-dominated businesses. The challenge lies in the fact that it is a male-dominated business. Being a leader belonging to a minority creates a situation where competence not only lies in having technical knowledge or general leadership characteristics, but also in acquiring an understanding of the male norm and being able to behave and communicate effectively in the organisation.In order to move towards a better gender balance at senior levels it is important to set measurable objectives on desirable proportions between women and men at management levels within the company. Focus and action are required to achieve this goal. At LKAB, the current target is to reach 25 per cent women in the total workforce by 2020. To date, LKAB has reached 19.4 per cent women in the total workforce, and the number of women in management positions is 19.9 per cent.It is of vital importance to create a non-discriminating working environment to achieve equal opportunities at the workplace, to be able to use the whole workforce as a resource for recruitment of professionals and managers, thereby improving decision-making, productivity, efficiency and profitability.Women as mine managers is not a utopia, but rather an effect of long-term investments in actions that result in equal opportunities for all employees.CITATION:Quinteiro, M and Sundqvist, Å, 2016. Women as mine managers – a utopia?, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016) , pp 43–48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Nathan T. Lowe

This report updates an accounting of mines and prospects in the Seafoam mining district, Custer County, Idaho, begun during mineral appraisal of the Idaho Primitive Area. Thirty-two mine and prospect locations have been added to the Bureau's Mineral Industry Location Subsystem (MILS) data base as a result of initial phases of mineral appraisal of the River of No Return Wilderness; most previously known locations were field checked and the updated information added to the data base. The district's major deposits include polymetallic fissure veins of gold-silver-lead-zinc-copper hosted by granodiorite and quartz monzonite which have been intruded by dikes ranging in composition from rhyolite to dacite, and vein type replacements of silver-lead-zinc-copper hosted by calcareous xenoliths imbedded in major intrusives. These deposits may be related to the intrusion of the Rapid River pluton or the Casto pluton. The dominant northwest structural trend is parallel to an aeromagnetic high, a weak gravity salient, and the Blue Bunch Mountain dike swarm.

Jan 1, 1983

By Burton Scott

A device for detecting carbon monoxide at ppm levels is described which is based on the measurement of infrared absorption at 4.65 microns. The unique feature of the nondispersive infrared instrument is contained in the optical design which includes a confocal cavity, increasing the effective optical path length by a large factor, thus greatly reducing the required package size. The cavity has the effect of reducing the total amount of radiation passing to the detector, but at the same time increasing the percent attenuation observed when adding CO, by a factor called gain. The radiation is chopped by a filter wheel which contains narrow band filters at 4.0 and 4.65 microns. The resultant signal produced by the pyroelectric detector is demodulated by the electronics to product an automatic gain control signal, proportional to the total radiation, and a difference signal, proportional to the CO present. Tests of a breadboard model are described which show cavity gains of 10 with noise levels equivalent to 2 to 10 ppm CO.

Jan 1, 1975

Flawed mining studies have been major contributors to poor investment decisions in mining for many years, contributing to the long period of poor industry profitability. Most of the major mining houses have now adopted quite formal processes and quality standards for mining studies to reduce the potential for poor investment decisions in the future. Other organisations such as the World Bank also have specific requirements for particular types of studies, such as bankable studies. This increasing requirement for rigour and discipline means a highly structured and phased sequence of studies is now required along with the development and adoption of industry-wide standards in mine ventilation studies. New terms in the study process such as ?independent peer review? and ?hold and review? are assisting in this process. More traditional terms such as ?feasibility study? and ?pre-feasibility study? now have much more precise technical definitions. Specific standards for the ventilation components of the various phases of a mining study are proposed in this paper.

Jan 1, 2009

By Kazuyuki Matsuzawa

A series of plate loading tests were carried out on a loam ground in order to investigate the influences of the plate size and the loading rate on the observed load-settlement relations. Two circular plates having diameters of 0.3 m and 1.0 m were used. Three types of loading methods were employed; 1) static cyclic maintained load test, 2) static continuous load test, and 3) rapid (dynamic) plate load test. An interpretation method called non-linear damping method was used to estimate a static load-settlement relation from the rapid plate load test signals. The derived static load-settlement relations match well with the measured results from the static load tests.

Jan 1, 2006

By Doug Anderson

Blast vibration seismograms are generally collected strictly for compliance with regulations. The peak levels (including dominant frequency) are typically all that are looked at. However, these records contain a lot more information about how a blast has performed. The seismogram is actually a record of explosive energy that was not used in fragmenting rock. The trick is to determine how to extract information that would be useful in analyzing blast performance.

Jan 1, 2013

Today computers are accepted as a standard item in industry and they perform a variety of tasks over a wide spectrum of activities from mine planning and CAD to data processing and spreadsheet work. However many problems particularly in the. area of decision making where there are no clear mathematical models available and usually the output or answer is dependent to some extent on a heuristic approach, don't lend themselves to conventional solutions using standard procedural algorithms. Recently a number of techniques have evolved primarily from the enhanced capabilities of modem equipment, which are capable of solving these problems. This paper is a brief overview of these rather unconventional developments of computer technology in the area of artificial intelligence with reference to their application in mining.

Jan 1, 1993

By J. D. Steenkamp, G. E. Williams

Keywords: Ilmenite, titania slag, pig iron, rutile, zircon Located on the eastern shores of South Africa, 180 km north of Durban, Richards Bay Minerals (RBM) produces approximately 2.0 million metric tonnes of product annually making RBM a leading producer of titania slag, high purity pig iron, rutile and zircon. Heavy minerals are extracted from the nearby dunes by dredging and concentration on a floating gravity separation plant, followed by separation of the ilmenite, rutile and zircon at the mineral separation plant located at the smelter site. The ilmenite is processed through an oxidizing roast followed by magnetic separation and is then partially reduced to an 85 per cent TiO2 slag in one of four six-in-line a.c. electric arc furnaces. The slag is milled and then classified into two product sizes suitable as a raw material for both the sulphate and chloride pigment processes. The high quality iron produced during the reduction process is further processed to produce various grades of low-manganese iron. Around 95 per cent of the products are exported, yielding a world market share of about 25 per cent of titania slag, rutile, high quality pig iron, and zircon.

Jan 1, 2006

By L. Ou

This paper reports on research on leaching pyrite in a germ-free system. The effects of mineral particle size, pulp potential and various oxidation agents on pyrite leaching were studied. The results indicated that a smaller mineral particle size leads to a higher leaching rate of pyrite. The optimum results were obtained with a mineral particle size of -0.037 mm. The pulp potential reflected the leaching process and an increasing pulp potential improved pyrite leaching. The leaching rate rapidly increased with the addition of oxidation agents such as Fe3+ and H2O2. However, the precipitate generated by ferric ion coated the surface of the pyrite and prevented further leaching.

Jan 1, 2007

By H Saw, M Cordova

Cemented rock fill (CRF) is often used to support open stope voids. This allows for the full recovery of ore while achieving global mine stability. In such cases, the exposed CRF masses require adequate compressive strength and stiffness to resist the forces and limit the displacement associated with movements in the rock mass surrounding the excavations. The CRF material preparation often involves the use of large particles, either from crushed rock or development mining waste. This means that conventional laboratory samples cannot be readily used to determine the laboratory strength. Consequently, a research project was undertaken to determine the influence of sample size on uniaxial compressive strength. This paper presents the results from CRF samples that were prepared using the same mix design and then cast into moulds with diameters of 150, 240, 300 and 400 mm. The laboratory testing also allowed a better understanding of the effect of particle size distribution upon the overall strength of a rock fill mass. The laboratory results were compared to a database of large-scale results from the testing of fill masses from a number of mine sites.CITATION:Cordova, M, Saw, H and Villaescusa, E, 2016. Laboratory testing of cemented rock fill for open stope support, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 755–762 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

The 108th Annual General Meeting of The South African Institute of Mining and Metallurgy was held at The Country Club, Johannesburg, Napier Road, Auckland Park on Thursday, 11 August, 2005. Welcome The President extended a special welcome to the guests and representatives of our sister institutes and other associations, also to recipients of awards, senior members of industry, Honorary Life Fellows, past-presidents, our members and other guests, among them the following: Dr Con Fauconnier, President, Chamber of Mines of South Africa Prof. Jay Barton, President, The Geological Society of South Africa V. Townshend, President, Institute of Certificated Mechanical and Electric Engineering, South Africa M. Livingstone-Blevins, President, Institute of Certificated Mechanical and Electrical Engineers, South Africa Prof. B. Lacquet, President, South African Institute of Electrical Engineers Dr F. Malan, President, South African National Institute of Rock Engineering

Jan 1, 2005

By Harold Price

ONE year ago, that is in January, 1923, there had not been constructed a single oil-storage tank of 55,000-bbl. or more capacity with a completely electric welded roof and bottom. Today, there are at least fifty 80,000-bbl. storage tanks completed, or nearing completion, on which both the roofs and the bottoms are electric welded. It is the purpose of this paper to describe, in a general way, the construction of these FIG. 1.-ELECTRIC-WELDED SEAMS AND RIVETS OF BOTTOM IN 55,000-BBL. TANK AT EL DORADO, KANS., SHOWING ALSO PATCH PLATE WELDED TO BOTTOM. welded roofs and bottoms, and to give their advantages over riveted construction. All of the following data and conclusions were obtained from observations made during the welding of tanks by the Welding Engineering Co. at Texas City, Tex., and Tonkawa and Burbank, Okla. As far as can be determined, the first electric welding on large tankage was completed in May, 1922. At that time the Empire Companies of Bartlesville, Okla., discovered a badly leaking bottom in a 55,000-bbl. tank at El Dorado, Kans. They had considered concreting this bottom, but because of the much smaller cost, decided to try electric welding; so a- contract was given the Welding Engineering Co. of Bartlesville, Okla. In this instance, no new sheets were added, the bottom being repaired by electric welding of all seams and rivets, Fig. 1. In some places where the original rivets were missing, the holes were filled by welding; patch plates were also added at certain badly worn spots. This tank has since been in service over a year and half, but no other

Jan 6, 1924

By J. A. Kosek

Work has been conducted under Bureau of Mines Contract Number HO 357078 to develop instruments for detecting CO, NO and NO2 in a mine atmosphere, using fuel cell technology. The approach has been to optimize the fuel cell sensor configuration for the specific detection of CO, NO and NO2 in the presence of other mine gases utilizing recent advances in catalyst, electrode and solid polymer electrolyte membrane technology. Para-metric testing has been conducted on three electrode sensor cells to define performance and life characteristics as a function of temperature, feed flow and applied sensor voltage. Extended life testing has been performed on sensor cell configurations exhibiting favorable characteristics. Reliable, efficient gas sampling and electronic control circuitry has been fabricated for use with the sensor cells, and integrated into devices to meet the performance and design specifications for portable, battery-powered, hand held direct indicating gas detectors for use underground. Twenty of the production-type, direct indicating CO detectors have been tested and delivered to the Bureau of Mines under the present contract. Three prototype diffusion head CO monitors have also been delivered for evaluation under the pre-sent contract. The gas sampling pump and related parts have been replaced by a diffusion tube assembly in which CO reaches the sensing electrode surface by diffusion alone. In addition, delivery will be made of ten direct-indicating nitric oxide detectors and ten direct-indicating nitrogen dioxide detectors. These instruments are very similar in design to the direct indicating CO detector.

Jan 1, 1979

By Laurance L. Oden

The Bureau of Mines is developing melting data for binary combinations of the alkaline earth fluorides and yttria to facilitate the formulation of slag composition. Liquidus and solidus temperatures and solid solubilities were determined for the BaF2-Y203 system, and the information is presented as the phase diagram. The phase diagram was constructed from data obtained by ceramography, X-ray diffraction, and thermal analysis of specimens encapsulated in small molybdenum ampoules. The data indicate a simple eutectic system with maximum terminal solid solubilities of less than 1 mole pct. The eutectic temperature is 1,343° C, and the composition of the eutectic is less than 1 mole pct Y203.

Jan 1, 1970

The sulphide ores of the principal lodes of the Boulder Mines are mainly composed of a schistose guess with a varying proportion of silica and lime, containing tellurides of gold, silver and mercury, associated with iron pyrites. It is a great difficultyto obtain pure and homogeneous samples of the tellurides for analysis, and from a number of tests made with excellent specimens it was found hardly possible to procure two to agree in analysis, the precious metals being found to be combinedwith tellurium in most varying proportions indeed, a close inspection of a partially crushed specimen will reveal, even to the naked eye, the various shades of colour characteristic...

Jan 1, 1901

By J Kelly, C Kelsey

The Autogenous Kelsey Axial Displacement (KAD) mill is essentially a short retention time centrifugal mill, designed to effectively harness extraordinarily high concentrations of input energy for efficient particle size reduction. The mill which has an operating duty band extending from primary to ultra-fine also has the unique capacity to generate fine and ultra-fine products from single stage size reductions of either coarse or fine mineral feeds, in both wet or dry operating modes. This paper covers developments following a recent optimisation programme which confirmed that mill shell speed and the velocity differential between the shell and the rotating internal disc assembly tips could be optimised in relation to specific energy for a given feed rate and feed size providing the product size remains constant. Subsequent test-work further demonstrated the versatility of the mill with duties ranging from the removal of surface contamination associated with heavy mineral concentrate particles to the production of premium ultra-fine talc, from a single stage of size reduction. Open circuit grinding of a rougher gravity concentrate to liberate gold ahead of leaching also highlighted the scope for the application of low cost KAD milling for a range of hydrometallurgical feed preparation duties, which involve fine and ultra-fine grinding.CITATION:Kelly, J and Kelsey, C, 2013. Advanced media-free fine and ultra-fine grinding - The Kelsey axial displacement mill, in Proceedings MetPlant 2013 , pp 152-161 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By Robert W. Decker

This report presents a survey of published novel coal cutting (mining) concepts and a brief discussion of each one. A preliminary evaluation follows which identifies promising concepts, emphasizing reduced dust generation and economic production potentials. The promising concepts are then studied more deeply and evaluated in more detail with recommendations given for further development action. The concepts recommended for further work include: Roan and Pillar Mining: Deep Cutting Continuous Miner Linear Cutting Rotary Head Miner Longwall Mining: Oscillating Continuous Water Jet Miner Deep Cutting Shearer

Jan 1, 1981

By Thomas Novak, Robert Goldstein

The analysis of a machine-luminaire configuration is a time- consuming process requiring the construction of a machine mockup, installation of a designated lighting arrangement, and an extensive set of illumination measurements. This entire process, however, is well suited to computer analysis. By simulating the machine geometry and the characteristics of the desired luminaires, the incident light levels can be calculated at the required set of points. This Bureau of Mines paper presents a general description of the techniques involved in performing this simulation.

By G McMillan, P Mulvey

"Geochemical characterisation is done based upon the geology and metallurgical batch testing prior to commencement of the operation of the plant.  Tailings repository design is based upon geochemical assessment of the waste material, as well as the geomechanical issues associated with storing the waste. The resultant conceptual and detailed design is incorporated into the environmental impact statement (EIS), upon which mine approval is based. The entire environmental monitoring and harm mitigation program, which is usually a condition of the Mine Lease approval, is based upon the applicability of the original characterisation.Tacit to this process is that there is no change in the geochemistry of the tailings, i.e. no change in the implications for acid & metalliferous or saline/neutral mine drainage (AMD/SNMD) generation. But any changes in milling and processing can have a substantive impact on the geochemical behaviour of the tailings metallurgy, and potentially render an operation non-compliant within the conditions of the mine license.Environmental and statutory approval implications for continuous improvements of metallurgy need to be understood because unintended consequences could cost more than the benefits of the improvement, and in some cases cost more than all the profit made from the mine.  Examples uncovered during audit and consultant practice will be presented together with a process to ensure implications for adverse environmental harm and license conditions are fully considered.*This paper is only available for individual download. It is not included in the conference proceedings*CITATION:Mulvey, P, 2013. Continuous improvement - how changes in metallurgy can have a substantive impact on environmental impact and closure - lessons learnt from environmental auditing, presented to MetPlant 2013 Conference (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013