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By B Ascott

As a prerequisite to achieving integrated regional production reporting across multiple sites, Newmont Australia initiated a project to standardise the configuration and use of mine control systems at three underground sites. This paper outlines the project and considers the outcomes which, in a number of cases, have exceeded the original objectives.

Jan 1, 2008

By R. Benito

This paper describes the development of a life-of-mine schedule (LOM) for one of the world's largest known sedimentary copper-cobalt districts located in the Katanga Province, Democratic Republic of Congo (DRC). A particular feature of the Tenke Fungurume LOM schedule is the considerable number of pits/phases for scheduling, each competing to provide the best ore available to a capacity-constrained process facility. This paper discusses the LOM scheduling objectives and constraints, data preprocessing steps such as ore binning, block aggregation and clustering analysis as a scheduling aid, the mine scheduling approach and results and conclusions. Mining Engineering, 2011, Vol. 63, No. 8, pp. 39-47. Official publication of the Society for Mining, Metallurgy and Exploration, Inc.

Jan 1, 2011

By T. D. Kaufmann

When Dr. David Gully solicited this paper last spring a few questions basic to commodity trade between the U.S. and world markets appeared perplexing. Why, for example, when the demand for aluminum was at a peak and when little expansion of capacity had taken place, was the dollar price half of what it had been at the previous peak? Or, why in 1984 when imports surged by 50% as the U.S. economy pulled out of its recession did the dollar not fall, but rather rose by 35%? And, why when the experts all seemed to agree that the dollar was grossly overvalued did the price of gold continue to decline? Surely these were extraordinary times for the mineral economist. When this paper was written in late July, 1985 the answers seemed clearer. The prices of many commodities were not low - the dollar in which they were denominated was too high. In other currencies many commodity prices were indeed high. The dollar was overvalued in trade terms by some 40% caused by an influx of short term coupon investments made by foreign money managers to take advantage of the higher short term interest rates in the U.S. relative to other international banking centers. With a decline in the relative difference in interest rates, an unhealthy buildup of foreign bank accounts and a perception that the dollar would fall, the dollar did start to decline rapidly.

Jan 1, 1985

By P. K. Parhi

The extraction of nickel has been carried out by the hollow fiber membrane technique using D2EHPA as the mobile carrier from the manganese nodule leach liquor after separation of Cu(II), Zn(II) and Co(II). The experiments were designed according to central composite design (CCD), which is a response surface methodology. The process parameters used for the experimental design were: pH, concentration of D2EHPA in the membrane phase, flow rate and H2SO4 concentration in the strip solution. Based on the analysis of variance, a reduced quadratic model was found to best fit the experimental data. The process parameters were optimized to maximize the nickel flux and the optimized conditions were flow rate: 630 mL/min; pH: 6.37; D2EHPA: 1.15 mol/L (1,150 mol/m3) and H2SO4: 2.39% (430.2 mol/m3), for a maximum nickel flux of 7.08 x 10-5 mol/m2.s, which was in good agreement with the actual Ni flux of 6.99 x 10-5 mol/m2.s.

By A. Boehm

"For recycling LD slag into the steel making process, the phosphorous containing calcium silcate phases have to be removed from iron oxide phases. One possible technical solution could be magnetic separation in a wide range of susceptibilities from ferromagnetic to paramagnetic. To check the feasibility of magnetic separation the distribution of the magnetic susceptibility in size classes as well as the liberation of the phosphorous containing phase were evaluated by a new method combining two dimensional physical property analysis with QEMSCAN analysis. The particle size classes of energy controlled comminution products were subdivided into fractions of defined magnetic susceptibility using a hand magnet of well known field properties (pick up method). On the one hand the susceptibility classes were wet assayed on the other hand analyzed by QEMSCAN followed by data evaluation using iDiscover 5.3.1(FEI), which was adapted to the data structure of two physical properties (size and magnetic mass susceptibility). The results allow the comparison of mass based (3D) cumulative distribution of grades from the wet assays with the area based (2D) distribution from QEMSCAN analysis, in order to control a systematic (size dependent) stereological error for this special type of material. As the physical separation property forms a crucial parameter the results from the liberation analysis by QEMSCAN can be interpreted more profound with respect to an expectable separation result. Once the various mineral compositions of the particles are assigned to the physical properties the Henry Reinhardt chart serves to predict the best possible separation result and thus the feasibility of a separation technique.INTRODUCTIONThe two Austrian steel plants operated by voestalpine AG produce about 650,000 t (voestalpine 2014) of LD slag in the course of steel production from pig iron according to the basic oxygen process blowing oxygen in the converter by an oxygen lance. The process is also known as the Linz Donawitz (LD) steelmaking process. By the addition of lime (CaO), carbon, phosphorus, silica, manganese and sulfur, which are present in the molten pig iron, shall be oxidized and bound in the slag either as oxide or silicate phases, or leave the slag in the gaseous phase (CO). The average chemical composition of the investigated LD slag is given in table 1."

Jan 1, 2016

By S. Bargigli, S. Ulgiati, M. Raugei, F. Cherubini

Metallic magnesium is mostly used in lightweight alloys in order to decrease fuel consumption in automotive applications. Several different production processes are currently used worldwide, and the magnesium production scenario is changing rapidly, with Chinese production increasingly dominating the world market. For the purpose of this paper, a novel approach to Life Cycle Assessment was applied, in which Material Flow Accounting and energy-based methods (Embodied Energy, Exergy and Emergy Analyses) are integrated and complemented, with a detailed description of the environmental hazards associated with emissions from all the different processes.

Jan 1, 2005

By E. V. Konopleva, H. J. McQueen

Steels in high variety have been providing strength and ductility for more than a century mainly through complex heat treatments following hot shaping. The economical and sustainable goal was a steel with the two operations combined through applying knowledge of dislocations and strengthening mechanisms aided by new mechanical and microstructural techniques. Primary hot reversing-mill rolling produced static recrystallization (SRX) between every pass to significantly finer grain size. Hot torsion showed that with lay-on temperature and rate of reduction suited to gradual precipitation of minor additions of Nb, the austenite grains would become highly pancaked; the existence of very fine subgrains along the grain boundaries (GB) could be deduced from tests on stainless austenite. The HSLA strip had to be water-jet cooled immediately to prevent SRX at austenite GB and ensuring complete transformation to ferrite avoiding grain growth after coiling. Confirmation on old mills and successful product led to the design of more flexible mills for wider range of compositions and products. A significant one was auto bumpers that reduced crash damage. More crack-resisting compositions were developed for strip welding into line pipe for arctic oil transport. Lower metal consumption and easier fabrication has resulted in more sustainable welded bridging.

Jan 1, 2015

By AIME AIME

ONE hundred and eighty-three A.I.M.E. members, W. S. Morris with an excellent technical program, John Suman, "oil" President of the Institute, and a Texas norther blew into Dallas for the fall meeting of the Petroleum Division at the Adolphus Hotel, Oct. 16-18. and the most successful result will give future meeting committees a high mark to equal. People were still talking of the terrific heat the week before and it was quite noticeable that with the lowered temperatures, the members were in fine fettle for the technical sessions. The total attendance on Friday noon was

Jan 1, 1941

Geophysical methods are useful non-invasive means of collecting subsurface information on the environmental impacts of resource developments. Techniques such as seismic refraction, ground probing radar and magnetics are well established tools for environmental studies of waste disposal sites. Repeat resistivity surveys, gravity surveys, and infrared or multispectral remote sensing hold great promise for monitoring environmental changes. Examples from New Zealand include geothermal field monitoring, which may involve the use of geophysics for .detecting changes of surface thermal activity, hydrothermal eruptions, induced earthquakes, contamination or depletion of shallow groundwater, and subsurface fluid recharge. Other examples include resistivity monitoring of contained effluent disposal ponds, tailings dams and landfills. Experience has shown that care is necessary to identify the natural variability of the parameter measured before drawing conclusions regarding an observed change.

Jan 1, 1994

By R Edwards

Greater efficiency of capture of minus 6 mm to fine micron size particles of free gold is achieved with the Knelson Concentrator. The development, principles of operation and recent innovations relating to this enhanced gravity concentrating device are described by the inventor, followed by a description of application and consequent economic benefits in low grade alluvial gold deposits by a large scale user of Knelson Concentrators in the Northern Territory of Australia.

Jan 1, 1990

By M. du Plessis, D. F. Malan

"The aim of any mine design is to ensure that the excavations remain stable for the period they will be in use. Various pillar systems are used to ensure that underground stopes remain stable and that mining activities do not affect the surface infrastructure through either surface subsidence or seismicity. Intermediate-depth platinum mines make use of in-stope pillars designed to fail while the pillars are being cut at the mining face. The pillar stress exceeds the loading capacity and the pillars crush as a result. The aim of the paper is to provide an overview of in-stope crush pillars. This will include the application, behaviour, function, mechanism, impact, and design of a crush pillar system."

Jan 1, 2015

By R. J. Beckman

This paper traces the history of mica mining in Alabama from 1870-1970. The decline of sheet mica production is noted and emphasis is placed on the more recent activity of scrap mica production and the development of the U. S. Gypsum Co. mica properties in Randolph County, Prospecting for weathered pegmatites of sufficient size to warrant development is a continuing challenge since most deposits are too small and all exhibit varying characteristics as to size, shape, and weathering. Quantity and quality of muscovite mica in the pegmatites is of utmost importance and its recovery during processing of the ore is described.

Jan 1, 1970

By G King, Q Shu, W Cao, F Gyakwaa, H Singh, S Wang, M Huttula, T Fabritius

Metallurgical slag, such as refining slag, is essential to enhance or promote steel cleanliness. The CaO–MgO–Al2O3–SiO2 system is the primary source of oxides-based inclusions. It plays a vital role in applications in various pyrometallurgical processes. Numerous thermodynamic databases and physicochemical properties of slag studies mainly focus on quenched samples and measurements at room temperature. Consequently, the present study explored the physicochemical, structural properties and crystallisation evolution for CaO–MgO–Al2O3–SiO2 glassy slags via in situ hightemperature Raman spectroscopy and synchrotron X-ray diffraction. The study was carried out by synthesising CaO–MgO–Al2O3–SiO2 slag with varying Al2O3/SiO2 ratios. The results from the in situ high-temperature measurement demonstrated a pattern showing a transformation of a broad peak from the glassy matrix to crystalline peaks. The study showed crystallisation of dominant phases such as Ca2SiO4, Ca2Al2SiO7 and CaAl2O4 that correspond and are attributable to changes of structural units during in situ high-temperature measurements. The results further showed a correlation between an increase and transformation in crystalline phases observed from the spectra obtained from non-isothermal heating of the samples.

Jun 19, 2024

By Whiten W. J

A simulation model was used to study the performance of various types of screen cloth on industrial vibrating screens. The model takes into account the effect of loading upon screen performance and predicts both themass flow rate and size distribution of the screen products.It was found that the use of the simulation model allowed the reconstruction of data for identical conditions and hence has simplified the analysis of the comparative performance of the screens. The dependence of performance upon operating conditions was found to vary markedly with screen cloth type.

Jan 1, 1977

By Ruilin Yang

"Blast vibrations are essentially a strain/stress wave propagating in rock or structures inthe vicinity of a blast. However, blast vibration has always been quantified in terms ofpeak particle velocity (PPV) or acceleration (PPA), and a meaningful relationshipbetween blast vibration and strain/stress has not been established. The determination ofthe dynamic strain from blast vibration may improve quantification of blast damage andselection of a blast vibration limit for critical structures or high walls. Dynamic strainrelates to rock mechanics or material strength more directly than peak particle velocity(PPV). This paper documents a method to calculate the three-dimensional dynamic straintensor from recorded blast vibration signals. The method is based on determination of thedisplacement gradient at a point of interest for each time instance during the vibrationduration. The method to calculate dynamic strain is applicable to generic seismicwaveforms including near and far field blast vibration from a production blast withmultiple blast holes. In order to minimize measurement errors the specifications of thespacing between monitors and the sampling frequency of the vibration recording aredescribed."

Jan 1, 2012

By D. G. Chedgy

Environmental improvement efforts are focusing with increasing intensity on pollutants resulting from combustion. The high cost of removing these pollutants at the power station is well documented. Physical coal cleaning has always been and should remain the most economic method of reducing sulfur oxide emission from coal combustion. It is critical in the selection of preparation plant circuitry to consider capital and operating costs, as well as the level of sulfur reduction. This paper describes the technical criteria which must be used for efficient process selection and summarizes the cleaning systems available or in development.

Jan 1, 1990

By Guilherme Liziero Ruggio da Silva

Uma marcha estável do alto-forno (AF) está ligada à consistência das propriedades químicas, físicas e metalúrgicas das suas matérias-primas (MP), especialmente, as do coque. As propriedades do coque são reflexos das propriedades dos carvões que lhe deram origem. Em termos de propriedades ligadas à natureza do carvão, a qualidade do coque é bastante influenciada pelo rank dos carvões, que compuseram sua mistura, ou seja, quantidades de macerais reativos e inertes, bem como suas propriedades coqueificantes, que é, exatamente, a habilidade inerente aos carvões aglutinantes de quando aquecido, amolecer, tornar-se plástico e solidificar em uma massa coerente. Neste contexto, o presente trabalho se propõe a evidenciar as mudanças no modelo de britagem de carvões da Gerdau Ouro Branco, bem como a operacionalização do padrão criado. Após a implantação, verificou-se a elevação de 1.8% em DI.

Aug 17, 2017

By Gerald J. Anderson

The Marquette District of Central Northern Michigan is the oldest of the Lake Superior iron districts with a mining history dating from 1852 up to the present. The total production of all types of ore through 1965 was 338,120, 146 long tons. Emphasis up to the 1950's was on mining the direct shipping ores; however, demands for higher-grade and better-structured ores in the last decade has resulted in a complete shift in emphasis to beneficiating the lowgrade Negaunee Iron-formation to produce high-grade iron ore pellets. The Precambrian sediments of the Marquette Range have been correlated with the Animikie Series of the Thunder Bay District, Ontario, and are contained in a westward plunging synclinorium that is approximately 3 3 miles in length and 3 to 6 miles in width. -The rock unit of major economic importance is the Negaunee Iron-formation that reaches a thickness of 2500 feet near the City of Negaunee. The primary iron content of the Negaunee Iron-formation averages 26 per cent, whereas the altered iron-formation approximates 31 per cent. The Negaunee Iron-formation has been divided into three principal types: diagenetic, oxidized, and metamorphic. The ores produced to date fall into four categories: high-grade soft ores, high-grade hard ores, siliceous ores, and concentrates and agglomerates (pellets). The soft ores generally are found in synclines and in fault-trough structures, bounded by mafic dikes along at least one side, and are mainly found in the basal portion of the Negaunee. In contrast, the hard ores occur in the uppermost portion of the Negaunee and are controlled by structural features such as folds, faults, and dikes. Iron-formation that has undergone diagenetic and metamorphic alteration makes up the main beneficiating ore types. Studies on the Negaunee Iron-formation have played an important role in the formulation of many of the theories on the origin of the Precambrian iron-formations.

Jan 1, 1968

By A. Kar

A mathematical model is presented for pure titaqium deposition from titanium tetrabromide on a stainless-steel (SS 304) substrate. Five three-dimensional, transient, and nonlinear partial differential equations are used to account for the diffusion of various species inside the deposition chamber and the thermal decomposition of titanium tetrabromide, titanium dibromide, and titanium monobromide at the surface of the substrate in order to determine the thickness of the titanium film deposited on the substrate. The effects of various process parameters on the deposition and shape of titanium films are examined, and under certain conditions, the deposited titanium films are found to have volcanic profiles.

Jan 1, 1992

By G. Baldermann, Hüttenrauch

Occupational health and safety are an important tool to increase a company’s economic efficiency. The integration of safety-related tasks into the overall structure of entrepreneurial tasks is an inalienable requirement for the sustainable achievement of positive effects. Investments into technical and personnel occupational safety that are tied in a streamlined organizational structure guarantee the improvement of defined indicators. The labor force is of central importance. Its added value ought to be ensured. It is necessary to move away from the employees‘ hazard awareness towards a safety awareness including many other aspects in order to save costs in the long run.

Jan 1, 2005