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By R. P. Viljoen, A. L. Sokolov

"The distribution of mineralized provinces is analyzed on the basis of their genetic link with specific blocks of the earth's crust including ancient platforms, mobile belts and zones of tectonicmagmatic activation. Mobile and fold belts surround the Siberian platform in Russia and the Kaapvaal craton in South Africa, with decreasing age zoning away from ancient platform margins. The main differences in the geological development of the two cratonic areas are: (1) the long period before the final stabilization of the Siberian platform (3600 Ma to 1600 Ma) and the comparatively short period of time for the stabilization of the Kaapvaal craton (3600 Ma to 3050 Ma) and (2) the intensive multiple activation of the marginal zones of the Siberian platform and the tectonicallycontrolled, magmatic sedimentary, intracratonic activity, typical of the Kaapvaal craton. Mineralization of the Siberian platform is largely characterized by marginal reactivation zones of differing ages although mineralized intracratonic Cu-bearing basins of Proterozoic age are also known. Mineralization of the Kaapvaal craton is mainly related to the formation of the intracratonic basins i.e., Witwatersrand (Au, U) and Transvaal (Au). The latter is characterized by multi-age volcanic-intrusive activity including the emplacement of Bushveld Complex (Cu, Ni, Pt, Cr, Au, V). The Siberian platform is characterized by the prolonged development of inherited mineralization from Archean until the late Mesozoic. The main period of mineralization in the Kaapvaal craton is restricted to the middle Proterozoic.The Baykal-Patomskaya and Namaqua-Natal mobile zones occupy similar positions adjacent to the Siberian and Kaapvaal cratons, respectively, and demonstrate similar modes of metallogenic development: i.e., the early formation of exhalative Pb-Zn-Cu deposits during the early stage and magmatic Cu deposits during the late stage. The more remote mobile belt near the Siberian platform, the Trans-Baykal, is characterized by intensive multi-age mineralization (Wo, Mo, Sn, fluorite), related to a period of tectonic-magmatic activation. The Saldania Belt occupies a similar position near the Kaapvaal craton but is known for its poor Au, and Cu mineralization. It does, however, have some similarities with Trans-Baykal Belt in regard to Mo-W bearing granitoids.The phenomenon of interference of geosynclinal, orogenic, platform, and tectono-magmatic activation regimes is known for the Russian section of the Pacific Ocean Volcanic Belt."

Jan 1, 1994

By L. Sun

In this work, strontium doped lanthanum ferrite (LSF) and their composite cathodes were fabricated by screen printing on yttria-stabilized zirconia (YSZ) electrolytes. Their electrochemical properties were evaluated by using electrochemical impedance spectroscopy and steady-state polarization methods. All the cathodes were screened by comparing their total polarization resistances before and after activation processes at different temperatures. The improved LSF composite cathodes were also screen-printed on YSZ/NiO half cells to fabricate solid oxide fuel cells (SOFCs), which have reached the output power densities of 170 mW/cm2 at 650 °C, 230 mW/cm2 at 700 °C, 304 mW/cm2 at 750 °C and 388 mW/cm2 at 800 °C.

Jan 1, 2005

By J. S. Kirkaldy, W. J. Slater, G. R. Mason

Activation analysis for copper and manganese in 10 mg samples machined from aluminum-base diffusion couples has been used in the study of ternary diffusion in the Al-Cu-Mn system. The accuracy, economy and convenience of the method are considered to be very competitive with other methods for analysis of such small samples. Neutron-activated aluminum-zinc alloys in the range from 10 per cent to 100 per cent zinc have been equilibrated with a known volume and the vapors subsequently condensed and collected. The vapor pressures relative to pure zinc (the thermodynamic activities) have been determined at 550°C' by recording the relative count of /'-rays from zn65 in the collected samples. The method is a sensitive one, although subject to serious obstacles to experimental accuracy.

Jan 1, 1961

By Y. Serres

In the past, conventional reflection seismic techniques were not very successful when applied to typical mining exploration: they lacked resolution in the shallow range or were not cost effective. By combining a light earth tamper source, special geophones and field procedures, a stacking process of the returning seismic events using a microprocessor system, and a sophisticated sequence of adapted digital data processing, Mini-Sosie achieves high resolution in the 100-ft to 4000-ft range. Additional advantages result from the very quiet nature of the source and flexibility of the system. Although Mini-Sosie might be used in the refraction mode, or for well velocity logging, it has found its main applications with the reflection technique.

Jan 1, 1978

By M. J. Merwin

Heat treated seamless tubular products are processed in a fashion that can be easily modified to produce dual phase microstructures, through the implementation of intercritical soaking prior to quenching. Dual phase steels are known to possess low yield strength compared to tensile strength. The steel line pipe market is interested in low yield-tensile ratio materials for application in reel barge pipe laying operations. In the current work compositions of commercially produced material already in use for the line pipe market were examined and dual phase microstructures were successfully developed. The microstructure and properties of the materials were found to be stable over the range of intercritical temperatures employed. Tempering temperature and, somewhat unexpectedly, small chemistry differences were found to have the largest influence on properties. Excellent toughness performance was observed in samples tempered at temperatures in excess of 550°C. Tempering in this temperature regime produced materials with strength suitable for application as API X60 line pipe. A difference in tensile strength between steels of similar chemistry was observed, and is not fully understood at this time. Welding performance was considered through simulation of three regions of the heat-affected zone. Neither intercritical temperature, nor tempering temperature, were found to have a significant influence on the heat-affected zone properties. The peak temperature achieved in the thermal cycle was the only significant factor. The hardness of the heat-affected zone was found to increase continuously with increasing peak temperature. While toughness was found to be low for both partially-transformed and coarse-grain heat-affected zones, the toughness of the fine-grained heat-affected zone was substantially better. Based on the results found in this laboratory study, a limited production trial is expected.

Jan 1, 2005

By B. N. Nandi

This paper is a study of the application of the science of coal petrology to the use of coal in the iron and steel industry. The petrography of coal is given the most attention, with some mention of coal palynology. The history of the petrographical analysis of coal is first out-lined, with a description of the various coal entities, and then the apparatus and experimental techniques employed for coal evaluation are discussed. The coke stability factor and the relation of coke strength to petrographical data are also covered, and some space is given to the new science of coke microscopy, in particular its use in following the oxidation of coals.

Jan 1, 1966

By E. S. Moore

To properly understand industrial conditions in Spain it is necessary to consider the early history of the country. Spain is very backward in many lines. They use the sickle for cutting grain, and plows for cultivating the land, which resemble those of Biblical days. In the great mining camp at Bilbao only one steam-shovel is in use, although about two hundred million tons of ore has been produced, and this almost entirely from open cuts. It is the lack of industrial development, such as is found in many other countries, which permits large mining enterprises to be controlled almost entirely by foreign capital, although Spain is such an old country, and which permits mines opened in the days of the Phoenicians to still operate. Such deposits in America would be exhausted in a comparatively few years. The Phoenicians are supposed to have reached Spain about 1100 B.C. and to have worked some of the properties in the Rio Tinto district. The Carthagenians invaded the country about 236 B.C., and they were driven out about 205 B.C. by the Romans. The Romans ruled until 483 A.D., when they were overthrown by the Visigoths. Then, about 711 A.D., the Moors from Africa became prominent and they were finally expelled by the Spaniards in 1492. Spanish power reached its zenith under Phillip II, during the latter half of the 16th century, and since the close of that century the country has lost its prominent place among the nations. There are some evidences of revival in the development of good roads, the construction of a satisfactory network of railways, and the building of magnificent thoroughfares through the capital city, Madrid.

Jan 1, 1927

By H. J. Burchell

"IntroductionTHE PURPOSE of this paper is to introduce the reader to rock bolting and its present application in mining.Rock bolting consists of bolting insecure rock to secure rock in order to form a safe structure. The insecure rock may be a weak beam or loose from arching or from sloughing. The material is strengthened and held in place before damage can result.Little is known of the limitations of rock bolting; to date, work has been carried on by trial-and-error, with large safety factors being used. Rock bolts have been principally used for roof support. Bolting offers a new field of support to the mining industry: it now has a permanent position as a ground control method.HistoryRock bolting is a relatively new means of support, its exact origin being unknown.Bolting has been in use at the St. Joseph Lead Company's property in Southeastern Missouri for the past twenty-six years, the first attempts having been hit-or-miss trials before a systematic attack was made. Many instances of occasional use of rock bolts have come to light .in widely separated mining camps, .some dating back forty years.The first installations were made as supplements to wooden timbering where space was restricted. The excessive costs compared to wooden timbering hindered their advancement for a number of years"

Jan 1, 1955

The SART (sulfidisation, acidification, recycle, and thickening) process is an effective way to separate copper and cyanide from each other in the waste stream of gold processing plants using cyanidation. Factorial experimentation has been conducted to create models of copper recovery, cyanide recovery, acid addition, and oxidation I reduction potential during SART. Economic analysis of the resultant models showed that SART is best operated with a sulfide to copper molar ratio of around 0.56, a pH of 4, and a minimised cyanide to copper molar ratio. The experiments also showed that thickening time may have drastic impacts on SART performance.

Jan 1, 2011

By T. Lu

Microwaves have considerable potential as an energy source in both mineral processing and metals extraction. In this research, the utilization of microwave radiation for the heating of a gibbsite type bauxite ore was investigated. Firstly, thermogravimetric studies were performed in order to characterize the dewatering processes of the ore. Secondly, both the real and the imaginary permittivities, which are the fundamental properties that determine the interaction of microwaves with any given material, were measured for the bauxite ore as a function of temperature. The changes in the permittivities were shown to be related to the dewatering processes. Subsequently, the effects of operating variables such as processing time, sample mass, particle size, microwave power, sample bulk density and carbon and magnetite additions on the sample temperature in a microwave field were studied. The results showed that under suitable conditions the bauxite ore could be readily heated. Therefore, there is considerable potential for the application of microwaves for the heating of bauxite ores.

Jan 1, 2007

By G. Azimi, C. A. Ang, F. Zhang

"Nickel recovery from laterite ores generates large amounts of solid and liquid wastes. This is primarily due to the low concentration of Ni (about 1.4 wt%) in the feed ore to the High-Pressure-Acid-Leaching (HPAL) process. It is known that the HPAL residue contains a high concentration of hematite, a commercially important source of iron in the steelmaking industry. However, the balance is natroalunite, containing sulfur, which is a detrimental element in the steelmaking process. Hence, to make the HPAL residue a suitable feed for steelmaking, natroalunite must be removed. The current work is focused on: 1) a thorough characterization of the HPAL residue obtained from Vale, and 2) a systematic investigation of an alkaline leach process to remove natroalunite. The characterization results indicated that there are about 83 and 12 wt% hematite and natroalunite in the HPAL residue, respectively. The leaching results indicate that sodium hydroxide is the best leaching agent, which results in 55 wt% reduction in the sulfur content. The results of this work enable the conversion of an otherwise waste product into a useful feedstock for steelmaking. Furthermore, this project could potentially have significant environmental benefits by reducing the amount of residue produced during the HPAL process.INTRODUCTION Conventionally, crude steel has been obtained by reducing iron ore containing oxides such as hematite (Fe2O3), magnetite (Fe3O4), and wüstite (FeO) in a blast furnace with coke. The product is then refined in a basic oxygen furnace to produce steel with useful properties (McGannon, 1969; Turkdogan, 1978). Steel has been sought for its desirable properties and its application is widespread throughout modern civilizations. Surpassing the growth rate of other materials, the annual demand of steel has increased at a compound growth rate of 5% over the last 20 years (Baddoo, 2008). The global demand for steel was reported to be 1501 Mt in 2016 and demand is expected to double by 2050 (Cullen, Allwood, & Bambach, 2012; World Steel Association, 2016). In recent years, to meet the rapid growth of demand, secondary resources for iron have been identified as strategic sources of iron (Das, Kumar, & Ramachandrarao, 2000; Li, Sun, Bai, & Li, 2010; Matschullat et al., 2000). The residue produced from high-pressure acid leaching (HPAL) of laterite ore has been identified as one of the important secondary sources of iron (McDonald & Whittington, 2008). Laterite ore represents 60% of the world’s nickel resources and accounts for approximately 40-50% of the world annual nickel production (U.S. Geological Survey, 2016). Therefore, the amount of iron residue produced by the process is substantial and its utilization will produce both economic and environmental benefits."

Jan 1, 2017

By Garston Blackwell

Abstract - During geostatistical estimation of block grades, the kriging process produces a measure of error, the kriging variance or the kriging standard deviation. Estimation of the block error depends on the semi-variogram model for a deposit, which reflects fundamental characteristics of a deposit such as (1) nugget effect, (2) range of influence of grades, (3) different local spreads of data as a function of average grade (proportional effect), (4) nested structures, and (5) underlying anisotropies in the data; this model may be affected by sampling or assaying limitations, however. Because the kriging error incorporates so many features of both the deposit and data to be used for estimation, it may offer a substantial improvement on block classification over traditional procedures such as data density. Practice indicates that the relative kriging standard deviation (RKSD) is particularly useful for block classification in measured, indicated and inferred categories. Plots of RKSD in plan and section also can be used to demonstrate where extra drilling and sampling would be most advantageous for upgrading the class of some blocks. Moreover, the use of grade and RKSD filters can show where material near cut-off grade is poorly defined, indicating sampling target areas to improve block classification in the vicinity of the ore-waste boundary.

Jan 1, 1998

By R. Lanthier, A. Broussaud, J. C. Guillaneau, D. Hodouin

This study presents a method for upgrading the information extracted from the measurements given by the sensors of a pilot grinding circuit. For that purpose raw signals are combined to process models for extracting, through filters, the best information on the process state. Two different filters are used; one is based on steady-state mass balance constraints and the other one uses dynamic mass balance equations allowing for material accumulation in the equipment. The filters are designed and tuned with the help of a grinding circuit dynamic simulator and are then implemented in the pilot plant. Their performances and usefulness are discussed.

Jan 1, 1989

By M. S. King

"A simple method is proposed for determining the long-term deformation behaviour of evaporites. The theory developed can be tested by measuring the change in diameter as a function of time of a vertical mine shaft opposite evaporite strata. Ultimate shaft closures predicted by the theory agree well with those calculated with the very much more complex theory of Serata (1968), provided that sufficiently high octahedral shear strengths are used in the former.An analysis of measurements made in an isolated opening in a Saskatchewan potash mine shows that the octahedral shear strength of the surrounding potash and halite was approximately 500 psi several years after the opening was mined. This value is less than that deter-mined experimentally for halite by Serata. The same data indicate, furthermore, that the in-situ octahedral shear strength is decreasing slowly with time.The current controversy regarding the actual deformation of evaporites will only be resolved by the cooperation of potash producing companies in releasing data on the long-term deformation of their mine shafts."

Jan 1, 1971

By Michael Arriagada, Ivan Arriagada

"As mines return to shafts to economically exploit deeper reserves, two methods mine owners use to minimize short term costs are: sinking shafts in phases and refurbishing old, existing shafts. While there may appear to be benefits to utilizing existing infrastructure, often this is not the case, resulting in missed deadlines and added costs. Similarly, if proper long term planning is not executed when sinking a shaft in phases, additional costs and downtime will be accrued. This paper will take an in depth look at both of these options with an eye towards optimizing costs, minimizing downtime, and facilitating construction. INTRODUCTION With the onset of mechanized mining and large capacity trucks, many mines turned away from shafts and began to use ramps to haul ore to surface. However, continual exploitation of mineral reserves located closer to surface, combined with the subsequent unearthing of additional resources at greater depths, forced mines to go deeper and deeper to extend the life and keep the operation running. In shallow mines, hauling ore by truck was an economical option. However, as mines get deeper, driving ramps takes additional time, and hauling over longer and longer distances becomes less economic, both in terms of cost and time. For this reason Mexico, in particular, has seen a jump in the number of shafts which have been put into production, as well as having a number of shafts in different stages of development and still more in the conceptual stages. Many of the shaft projects in Mexico are being designed in phases, with the hoist and equipment purchased capable of reaching the ultimate planned depth of the shaft, but with sinking operations stopping short at an intermediate depth. A loading pocket is then installed to start exploiting mineral at this depth sooner, with subsequent phases planned for a later date using either a rock pentice or bulkhead to separate the sinking operations from the active shaft above. Currently, we are directly involved in two such projects which are actively being deepened, as well as having seen various others already reach completion. If done properly with the long-term plan in mind, sinking in phases can be a very viable option, allowing for faster production while fully utilizing the equipment at various depths. However, there are many issues which can arise when sinking a shaft in phases that if not properly examined and planned for from the outset, have the potential to eliminate the gains hoped for when it was decided to sink in this manner."

Jan 1, 2019

By M. L. Jeremic

"Hydraulic mining consists of coal erosion by powerful jet s of water from hydraulic monitors operated by remote control. The broken coal is crushed and mixed with water and then transported from the face to the surface using gravity whenever possible. This is a simple, safe and productive method. It will easily satisfy North American productivity standards if the structural features and coal properties are favourable for water jet cutting technology (Kaiser Resources Ltd. , hydraulic mine). General ConsiderationIn open-pit mines, placer mining (Fig. I) and hydroelectric construction projects, hydraulic earth moving techniques have been successfully applied. The stripping and transporting of the overburden has been accomplished by means of large monitor jets augmented by slurry pumps and pipes. An extension of this technique has led to the underground extraction of coal and ores. To date, the method has been most successfully used in undergrond coal mining, because the coal can be easily cut and flushed away by water jets, and the rocks of the roof strata can be left behind. Due to this favourable situation, the hydraulic mining definition only relates to the underground coal mines.At present, there are four basic types of hydraulic mining, which can be defined according to the coal breaking technique used in each case. The methods are briefly discussed below:(1) Coal excavation may be carried out by conventional techniques, but the mine is designed and equipped for the hydraulic transport of the mineral from the working place to surface. Under these circumstances, the coal breaking may not be influenced by the water jet, however it may be indirectly involved. For example, pre-loosening of the coal may be done by water infusion-hydraulic fracturing. Water may also be used to flush the broken coal, which has been excavated either by drilling and blasting or by mechanical cutting, into the transport flumes. In other cases, a mechanical loader may load the coal directly into the hydraulic transport system, without using any water for the extraction process. This hydraulic mining concept is primarily used for hard and impermeable coal, such as anthracite."

Jan 1, 1980

By G Anders

Underground tests of slusher cables at first might seem to be quite simple and inexpensive. They do, however, take a long time and give results that may be ambiguous and unreliable. Also, because underground test conditions are not exactly duplicable, tests carried out at different times or in different mines could not be compared. An attempt was made to develop a laboratory test method that would provide for all factors affecting slusher cable performance underground in such a way as to make it possible to achieve comparable results from different series of tests by exactly duplicating test conditions. Such a method should also make it possible to vary individual factors systematically in order to give a proper assessment of the effect of changing conditions on cable performance. A set of tests, comparing the same two types of cable both underground and in the laboratory, is described. AN assignment at the Algom Nordic mine called for the comparison of two types of %-in. slusher

Jan 1, 1964

By A. E. Boudreau

Abstract-It has long been recognized that platinum-group-element (PGE) deposits in layered intrusions preferentially occur in intrusions that crystallized from high-Mg parent magmas. Recent studies suggest that evaluation of any given intrusion for economic PGE potential should also include assessment of the PGE, sulfur and chlorine concentrations in the cumulates and potential parent liquids. PGE: Magmas that contain relatively abundant Pt and Pd are the best candidates for forming economic deposits. Although analyses of coeval sills and dikes are the best indicators of primary magmatic PGE concentrations, analysis of the cumulates themselves is also valuable. For example, within the Stillwater complex, background PGE values in cumulates from the ultramafic sections of the complex contain, on average, several 10s of ppb Pt and Pd. Background concentrations of this order are suggestive that the magma was not depleted in the PGE. Sulfur: Conventional petrogenetic models for the formation of PGE deposits in layered intrusions require the PGE to have been concentrated during a magmatic sulfide-saturation event. In contrast, some hydrothermal models suggest that sulfur and the PGE were mobilized from footwall cumulates by upward- migrating, high-temperature hydrothermal fluids. Both models suggest that significant PGE deposits are likely to occur at and below the level where stratigraphic increases in whole rock sulfur concentrations occur. Chlorine: In both the Stillwater and Bushveld complexes the cumulate sequences below the major PGE-bearing zones contain anomalous Cl-rich apatite. The chlorapatite component of apatite in these rocks may exceed 40% and, in the Stillwater complex, typically exceeds 90%. It is stressed that pristine igneous mineral analysis and not whole rock data be used, as whole rock Cl concentrations may be affected by very localized (grain boundary), low-temperature alteration. Intrusions that crystallized from high-Mg, high-Cl magmas appear to have the best potential to host significant PGE deposits.

Jan 1, 1995

By H. Tan

The effect of carbonaceous matter on gold extraction was investigated in cyanide systems with pure gold as well as pre-robbing sulfide gold ores. Auger studies demonstrated that the carbonaceous matter preferentially smeared on iron sulfide rather than aluminosilicate surfaces during wet or dry grinding. During mechanically mixed leaching, coating of sulfides and silicates and stripping of carbonaceous matter occurred simultaneously. TEM and XPS studies indicated preferential coating in the form of elemental (graphitic) carbon at the edges and the defect sites of particles. Interestingly, carbonaceous matter extracted from the gold ore was predominantly graphite and not preg-robbing in a solution with a high KCN concentration. However, the carbonaceous coating had a significantly detrimental effect on gold dissolution when gold was pre-ground with the gold ore. Artificial coating on gold surfaces with the natural carbonaceous matter from the ore was also found to substantially retard gold dissolution. With the addition of the natural carbonaceous matter from the gold ore, gold extraction from two non preg-robbing sulfide gold ores was inhibited owing to carbonaceous coating. The presence of carbonaceous matter significantly reduced the current density for gold oxidation and increased the current density for pyrite oxidation. This could explain the fact that carbonaceous coating hindered gold dissolution while enhanced sulfide preg-robbing.

Jan 1, 2005

By Paul G. Dunn

The planning of underground mines is a complicated process involving geological, engineering and operational constraints. MIRARCO is in the process of developing a 5D Mining Exploratorium where 3D mining models are combined with time (4th dimension) and costs (5th dimension). The mining exploratorium is a collection of external and inhouse software packages specifically geared to help underground mining companies arrive at better mine plans. This paper discusses the progress made in the development of the 5D Mining Exploratorium and a change in mine planning philosophy by conducting frequent audits in a Virtual Reality Laboratory. The development of genetic algorithms for optimising stope sequences is also presented.

May 1, 2003