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Recent work on decoppering lead is reviewed CUS is formed rapidly even from dilute solutions of copper in lead. The mechanism of decoppering is discussed and an explanation for the retention of metals such as silver in lead is advanced. As decoppering tin appears to be an analogous process, the, Cu-Sn-S system is studied at 300°C.. CuS, which is not an equilibrium product, is found m decoppermg drosses. In the removal of nickel from lead, Ni3Pb2S2 is formed; preliminary measurements show the equilibrium nickel content to be greater than that obtained by stirring in sulphur. Decoppering bIsmuth IS thermodynamically favoured, but is complicated by the occurrence of CuBiS2 The Cu-Pb-S system IS the only one of the four studied where the equilibrium can be calculated simply, as the presence of ternary sulphIde or other phases invalidates calculations based on binary data.

Jan 1, 1971

The mining industry is generally regarded as a high risk industry, mainly because of the difficulties in estimating the tonnage and grade of mineral resources, the fluctuations in metal prices, mining problems and other problems which occur with mining in offshore and remote locations, such as appropriation or disruption to supply. As a consequence, finance providers require a high reward from mining projects. In the past two decades, the development of "mega" projects has led to the packaging of the finance becoming more sophisticated. Some would see this move as a measure of the evolution of banking rather than an intrinsic facet of mining finance itself. Project financial managers now require a thorough knowledge of all the financial tools which are available and have to be aware of the funding options so that they can put together a finance package which minimises the cost of the financing with the risk spread adequately between the partners of the financing. The different sources and types of finance for mining projects are described herein along with the factors which determine their costs. To understand the ramifications of financing mining projects, it is essential to appreciate the fundamental difference between debt and equity, which illustrates the importance of gearing. Costs of finance are determined by the interaction of supply and demand forces. Bankers and other financiers have become more adept at isolating a wide selection of risk elements and have devised a formidable range of insurance mechanisms. There is still a lot of money looking for good project risks and if a good project is properly presented and structured, financing can be obtained in today's market.

Jan 1, 1990

The Research on Refined Gold Bullions Surface Upgrading

Sep 13, 2010

THE Talisman mine is situated on the Waitawheta (pronounced Wytaffetta) river just above its junction with the Chinemuri (pronounced Chinnemurre) river near Karangahake, NZ. The explored reef-bearing portion of the claim includes the angleformed by the junction of the rivers and extends southwards for slightly over a mile (See Plate V.). The country is mountainous both rivers flowing through precipitous gorges.The trig. station on Karangahake mountain is almost directly above the workings on the Bonanza section and is 1680 ft. above river level, the adit from the gorge giving 1200 ft. of backs measured vertically. The officers of the N.Z. Geological Survey are engaged in a detailed survey of the Waihi district and the rocks of Karangahake are under examination. The rocks of the district are andesites and dacites much altered and silicified. One of these exhibits a columnar structure in the mass in the Waitawheta gorge near the surface workings on Taukani hill, also on the southern bank...

Jan 1, 1912

Detailed investigation was carried out on the dephosphorization of a number of phosphorus-rich manganese or samples of India by leaching with dilute sulphuric acid. Various process parameters like concentration of acid, liquid-solid ratio, temperature of leaching, time of leaching, and particle size of the ore were studied in detail for the three samples of manganese ore from central India, and optimum values were worked out on a laboratory scale. Preliminary studies show that certain ores which are not easily amemlible to appreciable dephosphorization by leaching with dilute sulphuric acid can be made amenable by :roasting to 700-900°C before leaching.

Jan 1, 1974

Despite technological improvements and better understanding of the hazards, coal dust explosions stilI occur. Experimental explosions in galleries in various countries extend knowledge with the constant aim of providing safer working conditions. The inadvertent ignition of an accumulation of methane is the traditional initiator of the coal dust explosion.There are specific parameters of coal dust explosibility and explosion propagation, including the important volatile matter in the coal, fineness and dispersibility of the dust and its concentration. Accepting that initiation cannot be absolutely prevented, it is necessary to consider explosion suppression. While both limestone dust and water are the chosen explosion suppressants, in practice water has more limitations to its efficacy when related to the degree of explosion violence. These data give rise to the criteria for explosion suppression, differences in favoured mining geometries, and using the same principles, to differences in suppression treatments.

Jan 1, 1988

By R B. Evans, M G. Townsend

In Northland, New Zealand, localised large deposits of halloysite clay have been produced by in-situ alteration of rhyolite volcanics of Pliocene or Pleistocene age, which were erupted through pre-Pliocene sedimentary strata and locally through Pleistocene basalt; and which were subsequently onlapped by further basalt flows. Alteration to clay has been a result of both hydrothermal and of meteoric processes, and decreases in intensity of alteration with increasing depth. The raw material is crushed and fractionated to produce a product of less than two micron particle size, which is of exceptional whiteness and brightness. The unique properties of the clays render them highly desirable for specialised ceramic purposes.

Jan 1, 1990

The Effect of Bulk Iron Concentration on the Copper Activation of Sphalerite at pH 9

Sep 13, 2010

The information age has definitely arrived and in fact has only begun to affect our business processes. Traditionally mining companies have been innovators and leaders with technology, but applying information technology systems to machines directly working on the mining extraction process poses challenges to those introducing the technology. Caterpillar is now presenting machine guidance and information systems for dozers, graders, blast hole drills, shovels, excavators, wheel loaders and trucks. These systems simply increase the flow of real information in real time and deliver it to the end users who can make informed decisions that effect real productivity gains and at the same time eliminate the role of the middle manager who used to monitor and control these activities. Technology also offers cultural changes that appear intangible, but offer significant gains to those that implement technology. Critics state that these intangible benefits are still available to traditional processes, however these intangible elements are never identified nor managed without the introduction of technology enhanced processes. The benefits of these technologies are real and dramatic, existing users offer impressive testimonials, but still the technology can be disproportionate in the time it takes to introduce to an operation. Caterpillar finds that senior to executive management needs to be a part of the technology introduction, to coordinate all departments and set technology strategies.  

Jan 1, 2000

By C Roche, G M. Mudd

The Morobe Province of central Papua New Guinea (PNG) has been mined for gold for nearly a century, although it is only in the past decade that large-scale modern mining commenced. The Hidden Valley gold-silver project began construction in mid-2006 and production by August 2009, and is located in the mountains above Wau in the headwaters of the Watut River. The mine is owned and operated by the Morobe Mining Joint Venture (MMJV), which also owns the Wafi-Golpu project, comprising the Wafi gold deposit and Golpu copper-gold deposit, situated in the Watut River Valley. Together they represent a potential mine of the scale of Ok Tedi or Bougainville or bigger. The MMJV is owned in equal shares by Newcrest Mining from Australia and Harmony Gold from South Africa. Although Hidden Valley was the first large-scale mine in PNG to engineer and build a tailings storage facility, poor environmental management during construction and early operations led to significant erosion of waste rock and sedimentation impacts throughout the ~200 km length of the Watut River. Since then, substantial efforts have been made to improve environmental management, especially waste rock placement and storage and water quality management. While the impacts from the Hidden Valley project appear to be reducing, the saga has heightened concerns by many along the Watut River and across PNG about ongoing impacts from mining.This paper presents the results of an ongoing project in the Morobe Province conducted by the Mineral Policy Institute examining the historical, current and future impacts of mining, including community views, social and environmental impacts and the monitoring and regulation of mining. Overall, there is a clear need to more fully integrate social and environmental issues into life-of-mine planning and go above and beyond regulatory requirements. In this way, some of the lessons learnt – by the community, MMJV and government – can be incorporated before, during and long after mining.CITATION:Mudd, G M and Roche, C, ?2014. Mining in Morobe, Papua New Guinea – impacts, assurance and self-determination, in Proceedings Life-of-Mine 2014 , pp 313–336 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By KEITH BARRONI

In the proposed criterion for coal a distinction is made between brittle and "psuedo-ductile" failure. This criterion is the basis for the development of new equations for coal pillar strength, including a transition from brittle fracture to pseudo-ductile yielding. In addition the equations obtained allow the critical minimum pillar dimensions to be calculated to avoid "catastrophic" and "ultimate failure".The validity of these formulae can be tested by comparing their results with pillar case histories derived from the literature.

Jan 1, 1988

LAKE MARGARET is situate high up on the West Coast Range of Tasmania, and lies in a roughly triangular valley formed by the ridge of Mount Sedgwick on the south, the ridge formed by Mounts Geikie and Tyndal on the west, amid a ridge connecting Mounts Geikie and Sedgwick on the east. Any description of this hydroelectric installation, however brief, naturally divides itself into the following sections:1. STORAGE BASIN, &c. 2. DAM. 3. PIPE LINES. 4. POWER STATION. 5. TRANSMISSION LINES. 6. SUBSTATION 7. VARIOUS WORKS utilizing the power.The Storage Basin used is the natural lake itself, which has a maximum length of 110 chains, a maximum width of 40 chains, and a mean arelj. of 300 acres. The water-level of the lake, which has been maintained by a natural dam, is 2143 ft. above sea-level. The approximate catchment area at present appropriated is 7 sq. miles, and the rainfall, on the average, about 144 in. per annum. It is possible to increase this catchment area by suitable races, &c. Dam.-The dam constructed is of very small dimensions, and is not a storage dam in the usual sense of the term. The natural storage ot-the lake itself was used by means of a channel cut through the natural dam and thence to the mouth of the lake, the lake level being thus temporarily lowered while the outlet pipes, screens, &c., were placed in position, and the channel was then closed again with a concrete wall in which the pipes and screens are set. This channel was cut partly through rock and partly through sand and conglomerate boulders for a total...

Jan 1, 1915

Ore sorting is a high capacity, low cost method of pre concentrating ores and in some cases of producing a marketable concentrate. In most cases it is applied to run of mine material, immediately after primary crushing and screening in sizes ranging from 10 mm to 150 mm. Recent developments in bulk sorting of friable uranium deposits have resulted in machines capable of handling fine materials with sensing and separation being achieved on a zone by zone basis. Modern ore sorting machines rely on the synchronous operation of four internal subsystems, feed presentation, sensing, data processing and separation. A variety of different sub systems is available which can be combined in various forms to produce sorters capable of handling a wide variety of mineral types. The benefits in using ore sorting cover a wide range of situations and are applicable to both established mines as well as new mining ventures. Reduced operating costs, increased productivity, capital savings, energy and resource conservation and environmental issues are all part of the reason why ore sorting is finding rapid acceptance in today's mining industry. The suitability of different ore types for pre-concentration using anyone of the variety of ore sorting systems can be quickly established using computer based techniques which require only small samples of the materials under investigation.

Jan 1, 1980

Three large deposits of good quality lignite were located and delineated in the Central Otago region between October 1978 and July 1979. The program was initiated and funded by Mines Division of the Ministry of Energy as part of the national Coal Resource Survey. The exploration work was carried out by Lime and Marble Limited on a contract basis (Bowman, 1980). The three deposits were all potentially mineable by open cast methods and possessed combined indicated and, inferred reserves in the order of 1000 x 106 tonnes. They ranked with the previously discovered Eastern Southland 1ignites and as such constituted an important national energy resource. Fifteen months later a second more detailed investigation of similar duration was undertaken by the Liquid Fuels Trust Board (LFTB). The objective was to upgrade and refine the geological data base of all of the nine South Island 1ignite deposits in order to make preliminary economic assessments of their potential. Again Lime and Marble Limited acted as the exploration operator (Bowman, 1981a, 1981b, 1981c).

Jan 1, 1983

Reasons are given for the seemingly excessive public concern with taxation of the mineral industry. Optimality of mineral extraction is a concept that requires careful definition in terms of one or more objectives. Once defined, the impact of taxation upon optimal mineral extraction may be studied; findings from earlier work on this topic are presented for two basically different cases. In conclusion it is observed that the pursuit of optimality requires the availability of highly skilled engineers; in the event of a large-scale mineral development it is this resource that is probably scarcest of all.

Jan 1, 1983

By Matthew I. G

A new process for leaching zinc sulphide concentrates with gaseous mixtures of SO2 and O2 in aqueous solution is described.The reaction of SO2/O2 with Rosebery, Mt. Isa, Broken Hill and Elura zinc concentrates yields zinc and iron sulphates, elemental sulphur and some sulphuric acid. Rates of zinc extraction are controlled by a surface chemical reaction without apparent interference from the elemental sulphur layer for SO2 concentrations up to 9 per cent in the gas phase. Pyrite in concentrate exerts an activating effect, possibly through galvanic interaction with the sphalerite. Metal extractions are dependent on SO2 and O2 tenors of the gas, particle size, and the acidity and zinc content of the solution, but are independent of the ferric ion level. Extractions also reach maxima at about 85°C.Generation of acid may be prevented by conducting the reaction in the presence of ferrous iron and at acidities of 40 g/l or greater. Zinc and iron levels in Elura lead concentrate may be reduced by leaching with SO2/O2.

Jan 1, 1981

The Golden Ridges Mine, one of the properties of New Guinea Goldfields Limited, is situated on the right bank of Nami Creek, not far from the township of Wau, in the Territory of New Guinea.The property is somewhat unique, in that the goldbearing ore-body occurs in the form of a flat seam-like deposit lying on a volcanic breccia, and covered with a mantle of overburden of decomposed porphyry. The overburden varies in thickness up to a maximum of about 65 ft.The ratio of overburden to ore is about 3 to 1. The practice developed is to strip the overburden by hydraulicking, and to mine the exposed ore under open-cut conditions, blasting to a vertical face, and using electrically operated scraper hoists for conveying the broken ore to the mill bins.The stripping of the overburden involves the boring of well-drill holes, blasting the holes and then hydraulicking the shattered material.

Jan 1, 1934

By X-F Zhao, J-W Li, L-P Zeng

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The formation of Kiruna-type deposits has been ascribed to either immiscible iron phosphate melt separated from silicic magma or precipitation from magmatic-hydrothermal fluids. The early Cretaceous Ningwu volcanic basin in Eastern China contains tens of Kiruna-type iron deposits. The orebodies are mainly hosted within the top zones of subvolcanic dioritic intrusions and along the contacts between these intrusions and adjacent volcanic rocks/strata.The orebodies are commonly associated with widespread brecciation and wall rock replacement. Magnetite formation was closely associated with extensive hydrothermal alteration that may extend kilometres, with both vertical and horizontal zonation. Field and textural data indicate that magnetite formed slightly later than albitisation but coeval with apatite and actinolite. Elemental analysis of magnetite and apatite from ores shows distinct features to those as igneous accessary minerals in the host dioritic intrusions, suggesting a genetic relationship to magmatic-hydrothermal processes. Magnetites have elevated TiO2 (up to 5 wt per cent) and V2O3 (up to 0.7 wt per cent), which implies that they are derived from incipient high-temperature magmatic fluids. It is concluded that the Kiruna-type deposits in the Ningwu basin most likely formed from high-temperature magmatic-hydrothermal fluids. The emplacement of dioritic intrusions into a subvolcanic setting likely plays a critical role in the development of Kiruna-type deposits.CITATION:Zhao, X-F, Zeng, L-P and Li, J-W, 2015. Kiruna-type iron deposits in the Mesozoic Ningwu volcanic basin, Eastern China – origin and relationship to subvolcanic dioritic intrusions, in Proceedings PACRIM 2015 Congress, pp 657–662 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Orr C. W

Continuing the systematic investigation of the influence of elements on the properties of lead(1). If the effects of additions of copper (up to 0.3%) on Port Pirie lead have now been determined in so far as creep rate is concerned.The results in the present paper contain also a survey of the influence of copper on the micro-structure of lead, a feature which has not appeared in the previous papers of this series. Further, it has now become known that creep is but little related to the more usually determined properties such as hardness and tensile strength. Since, however, these properties are of considerable importance in connection with the fabrication and use of this metal. Brinell hardness determinations have also been made and are here included.It is becoming more and more realised also that to be useful, creep data should refer to stresses of the order of those used in practice. This is due to the fact that as soon as deformation takes place, the properties of the metal are automatically changed. Lead does, of course, creep during industrial use, and probably (in lead chamber construction for example) extensions of the order of 5%...

Jan 1, 1938

Atlas Copco Construction and Mining Australia identified a number of issues in regard to the skill levels, labour turnover and productivity of our service technicians. In 1994 we were experiencing a labour turnover rate of 42 per cent per annum amongst our technicians. Exit interviews were held with each individual and one of the major areas of dissatisfaction was the degree of product training provided on our equipment, compared to what is required to be competent across the range of our products. These tradespersons were prepared to accept the reduced remuneration that an OEM offers, for the benefit of comprehensive, professional training that, in theory, could be provided. The truth is that we were achieving approximately 40 per cent of our target for training hours because of the demands of field service, pre-deliveries, etc. So, the summary was the same as the industry was experiencing at that time because of skilled labour shortages, production demands, etc people were employed and thrown in at the deep end. A recipe for failure that will be successful every time.

Jan 1, 1998