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Two types of low-sulphidation epithermal mineralisation may be recognised in volcanic terranes. Chalcedonic Silica- Adularia-Illite type mineralisation is most common in rhyolitic terranes, whereas Crystalline Quartz-Illite-(Adularia- Kaolinite) type mineralisation is more typically formed in andesitic terranes. A third type of epithermal mineralisation, the high sulphidation or Vuggy Silica-Alunite- Kaolinite-Illite type, is also common in andesitic terranes. Episodic violent boiling, accompanying hydraulic fracturing and hydrothermal eruptions, characteristic of geothermal systems in rhyolitic terranes, is stressed for the formation of Chalcedonic Silica mineralisation. Such boiling of deeply circulating meteoric groundwater, with some magmatic fluid contribution, provides chalcedonic veining, episodic banding and brecciation textures, adularia stability, bladed calcite, and extreme loss of H2S from the fluid to cause major gold deposition. Crystalline Quartz mineralisation is probably caused by the mixing of shallow acidic groundwater with ascending deep geothermal fluids beneath andesitic strato- volcanoes. The cooling effect, oxidation, and increased acidity, overcomes the dilution effect, and results in quartz deposition, illite (and locally kaolinite) alteration, and precipitation of metals. Extensive formation of base-metal sulphides further enhances gold deposition. Violent boiling is restricted to local structural dilation sites, potentially producing high grade "bonanza" gold mineralisation.

Jan 1, 1991

By Anthony Treasure

El presente trabajo señala la aplicación de la tecnología EMEW® para la recuperación de metales preciosos a partir de soluciones cianuradas diluidas que contienen plata y oro. La tecnología consiste en un proceso de electroobtención que ha sido desarrollado específicamente para la recuperación de metales en una sola etapa a partir de soluciones, hasta concentraciones de metal muy bajas, de forma que recupera plata y oro a partir de soluciones de lixiviación. Asimismo, este sistema ofrece beneficios como: menor costo de capital, costo de operación, simplificación de proceso, bajo riesgo técnico, mayor recuperación de plata, así como pureza del producto.

Sep 12, 2005

By R. N. Powell

The Pipeline ore body was discovered in March 1991. The construction of the new mine and mill did not start until early March of 1996. Upon completion of permitting and corporate project approval, the 289 million USD project was “fast tracked”. The commissioning began 11 months after start of construction and the project ended 40 million USD under the budget figure. The objective of this paper is to review and highlight the Pipeline Project history from discovery, design, lawsuits, permitting, and re-design through to current - 1998operating practices. Particular emphasis will review the process design, design mistakes, and design successes. The paper will review project history, feasibility, design concepts, operator training, construction, financial and the current operation. Additional discussion will review what design features worked and which did not work within the process plant.

Jan 1, 1999

By Sofoulis J

In the Archaean of the Kalgoorlie-Norseman area, the layered rocks have been subdivided into two sequences, both containing basic igneous rocks and sediments. The lower sequence is distinguished by the presence of acid volcanic flows and large acid sills. The upper sequence is unconformable on the lower one.In some areas, clastic sediments become coarser and pass into conglomerates. Th:s passage is accompanied by thinning of the beds.These features and their distribution suggest a basin of subsidence flanked by areas of shore-line conditions.Repeated igneous activity, including vulcanism, has occurred along the flanks of this basin. These different igneous and sedimentary environments have played an important part in the primary distribution of metals.A chronology of all basic and acid igneous activity, as well as sedimentat:on, has been established for the Precambrian of this area.INTRODUCTIONThe subdivision of Archaean rocks into those of basic igneous or of sedimentary origin has formed the basis for the nomenclature appearing in past literature. These subdivisions were distinguished as greenstones (predominantly basic igneous rocks) and whitestones (predominantly sediments), and it was generally accepted that the greenstones were stratigraphically lower in the sequence than the whitestones.Recent studies show that, between Kalgoorlie and Norseman, basic igneous rocks interfinger with and pass laterally to sediments, and that basic volcanic rocks occur at different stratigraphic levels. Younger Precambrian. units are also...

Jan 1, 1965

By Richard E. Thill

The Bureau of Mines' Oil Shale Data Bank (OSDB) was created in 1976 to serve as a centralized source for the storage, retrieval, and dissemination of technical literature, patents, and information on research projects in oil shale. Thousands of bibliographic references, patents, and research projects relating to the mining of oil shale have been identified, abstracted, and indexed according to selected keyword topics. The resulting data bank listings are contained in three sections, each with a separate keyword breakdown for use in rapidly identifying references pertaining to a specific subject. All references cited in the OSDB were published prior to an established cut-off date of May 1, 1981, when a redirection of Bureau of Mines programs resulted in the loss of project funds and the subsequent phasing-out of data bank operations. ACKNOWLEDGMENTS The oil shale data bank listings are the result of a team effort of the project staff. The contributions of Jimaleen Jansma for keypunching, information acquisition, and data entry, and John Brandenburg and Sandra Brake for keywording and information acquisition are gratefully acknowledged. Appreciation is expressed to the staff members of the Smithsonian Science Information Exchange, Washington D.C. for their cooperation in supplying data on recent research projects in oil shale for inclusion in the OSDB listings. Appreciation is extended also to the staff of the Gallegos Research Group for assisting with computer services to obtain the final printouts and transfer of files onto magnetic tape.

Jan 1, 1982

The following notes apply more especially to the purchase of silverlead ores produced in the neighbourhood of Zeehan and Dundas; for it is this class of ore that is principally mined in those parts, and which creates competition among the ore buyers.In the early days of this field, most of the ore passed through the hands of the first buyer who had sufficient enterprise to establish himself at Zeehan but in more recent times, competition has been so keen that there are generally three or four buyers tendering. lf the output was large this would not matter so much from the buyers' point of view but when we consider that the output of the field is only some 1,650 tons per month, and that of this 70 odd tons are produced by the Western and Montana mines, aud being sent home for realization, is withdrawn from local purchasers, there is really not enough for four buyers, especially at the present exorbitant prices they pay the miners.Some of the mines have a fixed sampling day, on which it is tacitly understood that the ore buyers will attend. Others, such as Grubb's Silver Mining Oompany, No-Liability, send round a printed reminder, stating the quantity of ore, and the date of sampling.

The principles of geometry and trigonometry are so continuously used by mining engineers for the purpose of accurately and intelligibly recording their measurements, that the writer is prompted to lay the following cursory remarks upon mine surveying before the members of this Institution in the hope of eliciting a free interchange of opinion upon details of this interesting branch of the profession. He proposes to deal with surveying only so far as it concerns the mining engineer, not to intrude upon the domain of the professional surveyor, and, in this instance, to discuss more especially that which may be termed the mechanical, rather than the mathematical side of surveying.In the latter part of the eighteenth century and the beginning of the present one, the usual underground surveying equipment in the English metalliferous mines, consisted of a magnetic needle in a fiat square wooden box of about 9-inch sides, a two-foot rule, a long cord, aud a stool, upon which to place the needle and box. The operator took his bearing by sending his assistant with the end of the cord as far in a straight line as the length of the cord would admit.On its being drawn that he held its end in one hand and placed the side of the compass-box against it with the other, and noted the bearing thus found either by a book entry, or by ticking it off with a piece of chalk on the board the compass lay in. He then measured the cord with a two-foot rule. It is needles to say that with these appliances the accuracy of the results were open to question, and mining surveying was not unduly popular.In the present day, engineers have the advantage of using instruments brought to such a state of perfection, and of employing such an exact system of underground surveying, that inaccurate work must usually be attributed either to lack of care, or lack of ability in the operator.

Gold in the stibnite veins of Costerfield, Victoria, was described in 1922 1, prior to any mineragraphic examination, as (a) free yellow gold (b) free rusty gold and (c) combined gold. The free yellow gold occurs in quartz and will amalgamate with mercury. The free gold of dull, rusty or copper-red colour occurs in massive stibnite and has been stated to resist amalgamation with mercury. The dull colour is only skin deep and the colour is bright when the rusty gold is scratched. The appearance of the rusty gold is spongy or cellular and it generally occurs near small cavities in the stibnite. The suggestion that the cellular character indicated the removal of a certain amount of stibnite leaving a residue of se.condary gold cannot be sustained.It now appears probable that the rusty gold is formed by the primary dissociation of a gold antimonide and is distinct in origin from the normal yellow gold which is deposited with quartz or stibnite from auriferous mineral solutions.The combined gold referred to in the earlier paper was the gold contained in the stibnite as revealed by assay. Such gold was at first thought to be either dissolved in the stibnite or else present as free interstitial particles too minute for observation in transmitted light in thin sections.Subsequent examination of numerous polished,surfaces disclosed the small particles of gold occurring in the grain boundaries in aggregates of fine grained stibnite 2. The assumption that all the gold in the stibnite, as revealed by assay, occurred in this way is now known to be incorrect, because limited amounts of a gold antimonide have been found in the veins.

Jan 1, 1952

By M. A. Raza

Cable shovels are capital-expensive and primary production equipment in many surface mines. The forces acting on the shovel dipper vary as the dipper moves through the muck-pile. The variations in the forces cause stress loading of the components of shovel and dipper resulting in unplanned downtimes, reduced shovel efficiency, and high mining costs. A potential solution to the above problems is the deployment of an intelligent shovel excavation (ISE) technology, with real-time formation identification, recording, and knowledge transmission capabilities. This research advances the ISE technology by developing dynamic model of cable shovel dipper using Newton-Euler techniques. The model includes the dynamic cutting and dynamic weight forces acting on the dipper as it moves through the muck-pile.

Jan 1, 2011

By Verya Nasri, Scott Thorburn

The City of Toronto and the Toronto Transit Commission (TTC) have conducted an Individual Environmental Assessment (EA) for a 6.2 km, 4-station underground extension of the Spadina Subway from Downsview Station to Steeles Avenue. This Environmental Assessment Study was performed in three phases including routes and general station locations, alignments and station concepts and detailed assessment of the effects of the undertaking. URS Canada Inc. has led the consultant team for this Study. The anticipated total duration of the project is approximately 6 years and its estimated total cost is about $1.4 billion. This paper presents the planning process of the project, the environmental and engineering challenges, and the measures taken to address them.

Jan 1, 2007

By Green P. F

Apatite Fission Track Analysis (AFTA) is a thermal history reconstruction tool that enables determination of magnitude and timing of maximum paleotemperature and paleo-geothermal gradient at the time of maximum paleotemperatures. From this information, the amount of section missing at major unconfornities can be estimated and incorporated into basin models. The Gippsland Basin has a number of distinct problems that can be tackled using AFTA. 1. The nature of the regional break between the Late Cretaceous-Tertiary Latrobe Group and the underlying Early Cretaceous Strzelecki Group. 2. The tectonic history of the basement flanking the basin and its effect on sediment composition. 3. The age of igneous activity in the basin, as typified by the widespread basaltic plugs and dykes intruding the outcropping Strzelecki Group. Major uplift and erosion within, and adjacent to, the early Cretaceous rift basin in the Mid-Cretaceous, at -95 to 100 Ma, initially constrained the Latrobe Group depositional area to the central deep of the Gippsland Basin and provided an elevated source of quartz-rich detritus for the Latrobe Group reservoirs. This is in marked contrast to the preceding period in the early Cretaceous when contemporaneous volcanism dominated as a source of detritus, producing quartz-poor lithic sandstones, in which a host of attendant diagenetic reactions destroyed their reservoir potential. Initial uplift and erosion of the volcanogenic Strzelecki Group also occurred in the mid-Cretaceous as revealed by a number of distinct inversion structures, and erosion of this material will have locally provided very poor quality sand to the basal Latrobe Group.

Jan 1, 1992

By H. Powell

"This paper discusses how elemental analysis of conveyed bulk flows in real time using PGNAA (Prompt Gamma Neutron Activation Analysis) technology has resulted in significant improvements in advancing plant control in mineral processing operations. PGNAA through belt, full stream, continuous, multi-elemental, real time analysis technology is explained. Capabilities and limitations in plant operating environments are discussed including comparison with other real time, on-line technologies through review of published information available for on-conveyor minerals applications. Case studies include an iron ore and copper-gold company, both of which consider the technology an essential component in advanced plant control necessary in new process flow sheet designs, rather than an optimisation tool.INTRODUCTION Process operators rely on supply of a reasonable ore quality and consistency from the mine. Unfortunately neither the mining nor process operators have much control over the ore quality once it has been put into the crusher. Grade control typically stops once the material is designated as ore and the process plant operator needs to process it irrespective of quality. Plant control is most effective when technologies measure process streams directly and preferably in real time. Measuring sampling streams that are not representative of the primary flow will result in incorrect plant control decisions. Sampling coarse conveyed flows is expensive and impractical at many operations, however, this does not mean those flows cannot be measured. Investigations to find techniques suitable for real time elemental analysis have focussed on the application of known laboratory techniques to process streams. For conveyed applications, development of neutron irradiation techniques were most promising and early studies indicated potential success for bauxite measurement (Beurton et al, 1995). Tran & Evans (2001) concluded there was no equivalent technology to PGNAA in terms of material penetration power and that the technology was eminently suitable for basic industries such as cement. Nelson and Riddle (2003) evaluated PGNAA for possible use in the phosphate industry by using a unit installed in a cement plant to test performance on phosphate samples and ultimately recommended its use for further characterisation of the mine’s various ore types to improve stockpile allocation and grade control"

Jan 1, 2014

Kudremukh Iron Ore Company Ltd, a wholly owned Government of India Enterprise, was established in the year 1976 to develop mine and plant facilities to produce 7.5 Mtpa of high-grade iron ore concentrate at Kudremukh. The mine and plant facilities were commissioned in 1980. In view of high demand for iron oxide pellets in iron and steel industry worldwide and as a diversification activity, a pelletisation plant of 3.0 Mtpa capacity was commissioned in the year 1987 at Mangalore for production of high-quality blast furnace and direct reduction grade pellets for export. The pellet plant capacity has been increased to 3.5 Mtpa by technological improvement which included installation of roll press for quality and productivity improvement. In addition, the pellet capacity is being increased to 4 Mtpa by the addition of Shaft Pelletising Furnace plant.

Jan 1, 1999

By J Samosir, L Snyman

Northparkes was the first mine in Australia to use block cave mining method which relies on gravity and natural rock stresses to fragment and recover the ore. It was also the first hard rock mine to use hydraulic fracturing, in conjunction with CSIRO, to promote caving of E26 Lift 1. The technique was later used on E26 Lift 2 wedge and E48 prior to undercutting.Northparkes production is currently sourced from the E48 Lift 1 block cave mine and E26SLC. The E48 block cave contains economic ore to the north and south of the current cave footprint. To recover this ore the footprint has been extended on the north and south with two extraction drives and one extraction drive, respectively. Modelling of cavability above the additional drives indicated that the cave would not readily propagate to a sufficient height of draw to mobilise the ore and tended to arch over into the existing cave. To address the modelling results and to reduce the risk of the project, rock mass preconditioning was adopted.This fracturing campaign was performed from surface drill holes adjacent the subsidence zone angled to intersect the higher grade and higher elevation ore zones.Optical televiewer surveys, run prior to fracturing, picked intervals and fault zones to be avoided. Holes were resurveyed post-fracturing to detect newly created fractures and as a measure of success of the program.During fracturing operations water and gel fractures were run at varying depths and pumping pressure was logged for each fracture. The mine seismic system monitored significant events and dye in the fluids utilised for tracking water inflow locations during underground inspections.Towards the end of the project, guar fibres from gel were detected within the mill circuit and required treatment to resume optimum processing.CITATION:Webster, S, Snyman, L and Samosir, J, 2016. Preconditioning E48 cave extension adjacent to an active cave, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 471–478 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By H. Meseck

The new building of the Central Bank of Iraq in Baghdad was footed in difficult underground conditions on more than 600 reinforced concrete driven piles, with cross-sectional diameters of 45 x 45 cm and pile lengths of 12.0 to 18.0 m. The necessary embedded depth and the bearing capacity thus reached were established on all 600 drives piles by means of dynamic pile tests. For the calibration of the dynamic pile tests, 6 static pile load tests were carried out. The execution of the construction and the results of the extensive tests on the building site are shown.

Jan 1, 1989

By C. F. Cornell, R. C. Emmett, D. A. Dahlstrom

FOR many years the disk-type and cloth-covered drum filters have found widest application in liquid-solids separation, which uses continuous filters. The disk type is less expensive, occupies less floor space per square foot of filtration area, and requires negligible down time for filter media changing. However, because filter cloth is billowed out by the blowback in the cake discharge, it is very short-lived if the scraper blades are set too close. Consequently cake weight is very important in assisting cake discharge, which normally necessitates a minimum cake thickness of 3/8 to ½ in. Also, the vertical position of the disks eliminates the possibility of efficient cake washing for removal of soluble values. The disk-type filter is generally limited, therefore, to applications that require no cake washing and form relatively thick cakes within the normal range of filter cycle times. The conventional cloth-covered drum filter is a more flexible unit, permitting wider variation in the percentage of cycle time devoted to cake formation, dewatering, or washing, as required by the application. Thinner filter cakes can be discharged because a horizontal line across the filter medium at the location of the scraper blade is equidistant from the edge of the blade at all points. The scraper blade therefore may be set a short distance from the filter medium or, where wire winding is not used, a floating scraper can be utilized so that the contour of the cloth can be followed. The drum filter is generally employed when there are difficult filtering slurries with resultant thin cakes or when cake washing to recover soluble values must be practiced. Difficulties sometimes encountered in continuous filter operation can be summarized in the following four categories: 1) Low filtration and/or washing rates due to blinding of the filter medium. 2) Poor cake discharge resulting from sticky cakes, filter medium blinding, or too thin a cake for the particular type of filter. 3) High filter media costs caused by short life and frequent down times for cloth changing. This results from blinding or from abrasion by the scraper blade when cakes are thin. 4) Blowback of filtrate at cake discharge because not enough air passes through the cake to purge the drainage area and filtrate lines during dewatering. To reduce or eliminate blinding tendencies several modifications have been tried, for example, cover-cleaning showers, blowback under the feed slurry, and snap-blow cake discharge. In many cases, however, this simply retards the rate of blinding, since the filter medium is kept clean at its outer surface only by these methods. As blinding usually occurs within or on the back of the medium, the operator is finally forced either to remove the cloth and scrub the medium intensively with a cleaning solution or acid-rinse it on the filter—all resulting in down time, short cloth life, and additional costs.

Jan 1, 1959

Keywords: Pyrometallurgy, zinc, electrowinning Zincor has been producing zinc since 1969 via the roast-leach-electrowinning process. It is the only primary zinc producer in South Africa, and currently supplies the entire country with zinc. The plant was built by Goldfields of South Africa, on the site of an old gold and uranium mine. Since then, the ownership of the plant has changed a couple of times, and the plant and process have also been improved. Production output has increased from around 80 000 tons per year to more than 110 000 tons per year. This was done mainly through increasing the capacity of the roasters and acid plant. Zincor produces four main grades of zinc: SHG, Zn1, Zn2, and Zn4, in three shapes: a 25 kg ingot and 1 and 2 ton jumbos. In 2005, a pre-alloy furnace was built that enabled the production of jumbos pre-alloyed with aluminium. This has allowed Zincor's customers to improve the efficiency of their continuous galvanizing lines and to lower their production costs.

Jan 1, 2006

By J. Kirsch

Keywords: Pyrometallurgy, pneumatic transport, pneumatic transport Dense-phase pneumatic injection has begun to replace more traditional furnace-feeding systems. The paper describes the technology as it is applied to processes where the back pressure at the point of injection is greater than 50 kPaG. It reviews earlier systems of injection and more recent developments that address concerns for instantaneous control in modern smelters. The new technologies fall into two groups, (1) modified pressure-difference control (sub-divided into simple and complex) and (2) mechanical-feeder-based control. Features of current injection systems include feed splitting in two forms, passive and active, and co-current injection.

Jan 1, 2006

By M. M. Gilkey

Pegmatites in Colorado occur for 150 miles along the Front Range (eastern-most range of the Rocky Mountains) from Larimer County on the north to Canon City on the south, and west into the Gunnison area. Many of the deposits have been classified. Minerals found in the various dikes include beryl, scrap and possibly punch mica, lithium-bearing minerals, columbite-tantalite, feldspar, and several rare minerals. Pegmatites are abundant in the Crystal Mountain district in Larimer County. About 5 miles south of the Crystal Mountain district and often identified with that district is the Hyatt pegmatite area. The Hyatt Ranch deposit has attracted particular attention because of the comparatively high beryl con-tent of the upper part exposed in opencut workings.

Jan 1, 1960

By Cesar Sáenz Acosta

El presente texto señala las mediciones de impactos que se han realizado a los programas de responsabilidad social de una empresa minera. Esta medición se realizó a través del cálculo del indicador “Retorno social de la inversión”, aplicando el modelo SROIM o Gestión del Retorno Social de la Inversión. Los proyectos de RS medidos permiten actuar a las empresas de manera responsable con su comunidad y comprenden: salud y nutrición, educación y desarrollo económico. Asimismo, esta medición contribuye a mejorar la comunicación de los impactos generados y desarrolla una gestión adecuada de estos.

Sep 12, 2011