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By Okura T, Hino J

Coal utilization for copper flash smelting in Japan was initiated due to the sudden upheaval in the price of oil in the last ten years. A major portion of the heavy fuel oil has already been replaced by coal resulting in a corresponding decrease in energy costs. In addition to energy cost savings, an interesting metallurgical phenomenon was observed in flash smelting operations. Unlike oil combustion, coal is not burned completely in the shaft. A considerable fraction of coal particles remain on the surface of slag and are burned at the settler. Chemical investigation has shown that oxygen potentials at the settler have consequently decreased, bringing the slag and matte phases into reducing conditions, thus oxidation and reduction can coexist in one flash smelting unit. As a result, a decrease in magnetite and copper contents in the slag, elimination of furnace hearth build-up and dissolution of intermediate layer between matte and slag have been observed. In general, these led to improvements of furnace operations. However, thermodynamic investigations have shown that some minor elements such as As, Sb, Bi and Pb concentrate from slag to matte. Results evaluated on the basis of thermodynamic data relatively agree with practical observa- tions. Consequently, for coal utilization in flash smelting operations it will be necessary to control oxygen potentials from the stand- points of copper loss in slag and minor element Distributions.

Jan 1, 1987

By Sandy W

This paper examines the effects of a significant number of plant alterations and modifications to the lead flotation circuit during the past five years. Metallurgical effort is directed largely at the flotation performance of middling streams and current strategies are discussed. The automatic control of cell destination and collector additions are outlined in the latter section of the paper, along with a description of control hardware in current use.

Jan 1, 1983

By S Arthur, J Mills, A R. Penney

A key aspect of seismic management for narrow vein stoping of the west zone at the Beaconsfield Gold Mine has been the development of a fully remote extraction method that does not require personnel access to sill drives within the orebody once stoping commences. Initially, sill driving within the reef is undertaken in a conventional fashion under geological control. Sill drives are developed at a vertical backs-to-floor height ranging from 7 - 12 m. This mining stage includes all activities prior to the commencement of stoping, after which no personnel enter the unstoped section of the sill drive at any time for any purpose. The key aspect of the remote mining cycle is the use of footwall drill drives paralleling the ore drive at a minimum separation of 6 m under survey control. These drives provide the platform for fan drilling of the orebody. Up to 20 m strike panels are blasted in a single shot using electronic blasting techniques. Ore is mucked from the extraction level sill drive using tele-remote loaders. Aerials for tele-remote operation are installed through boreholes from the footwall drive, negating the need for personnel access to the sill drive. Once mucking of a stoping panel is complete, a laser scanning survey instrument is used to survey the final void for subsequent design and production reconciliation purposes. The survey instrument is mounted in the bucket of the tele-remote loader, and is also operated remotely. Finally, tele-remote loaders are used to dump waste rock fill from the upper sill drive. A system of flags and cameras installed in boreholes from the footwall drive assists the operator in locating the live stope edge during the filling cycle, again negating the need for personnel access.

Jan 1, 2008

By Clark G

The latest addition to the grinding circuit at Bougainville Copper Limited is another 5.5m by 7.3m primary mill (No.13). The mill can operate in a primary or secondary mode. Its distinguishing feature is its capability for speed variation, by means of a cycloconverter-fed synchronous ring motor. The engineering and metallurgical reasons for selecting such a drive system are described together with aspects of the installation and commissioning. Results of investigations into the relationship between mill speed and grinding efficiency are presented. It is concluded that mill speed variation within the range 70 to 80% of critical speed has very little effect on grinding performance. Beyond this range, grinding performance deteriorates. The same conclusions were reached when mill speed was varied at reduced ball charge levels.

Jan 1, 1986

By Schofield N. A

The cross-sectional method of stope grade estimation at Cobar Mines has consistently had several shoneomings, me most imponant of which being mat stope grade is significantly overestimated in the high grade lenses.The use of mree-dimensional ore lens modelling improved the grade estimation and ore waste definition but significant overestimation still occurred in me high grade stopes, particularly those wim extremely variable grade distribution. The implementation of an indicalor kriging based method for mapping of me high grade copper mineralization has significantly improved the quality of copper grade estimates and provides a mineralisation geometry similar to that generated manually by me mine geologists. This paper presents the results of a test case study in the application of indicator kriging to the mapping of the copper grade in two stopes in the QTS North mineralisation. The results are encouraging in that they prov ide coofi rmation of the geometrical model developed by the geologists and much improved estimates of the grades of me stopes whencompared to me grade reponed from mining these stopes.

Jan 1, 1993

By R Grogan

Nautilus Minerals Inc is a sea floor resource exploration and development company focused on developing the Solwara 1 Project, a copper-gold sea floor massive sulfide deposit in the territorial waters of Papua New Guinea, for which it holds a mining lease and associated environment permit.Economies depend upon four key types of capital: built, natural, financial and human. Natural capital consists of the ‘minerals, energy, plants, animals, ecosystems (climatic processes, nutrient cycles and other natural structures and systems) found on Earth that provide a flow of natural goods and services’ (Daly and Farley, 2004). Many ecosystem goods such as fish, fruit and water are already valued and sold in markets; however, some ecosystem services are not amenable to markets and have remained unvalued in traditional accounting methods, even though they provide significant value (such as flood protection, climate stability etc; Batker and Schmidt, 2015).There are now economic methods available to quantify and value natural capital and many non-market ecosystem services. When valued in dollars, these services can be incorporated into a number of economic tools, including benefit-cost analysis, accounting, environmental impact statements, asset management plans and rate of return on investment calculations. Their inclusion ultimately strengthens decision-making. When natural capital assets and ecosystem services are not considered in economic analysis, they are effectively valued at zero. This omission can lead to poor decisions, inefficient capital investments, higher incurred costs and losses due to unexpected events (Batker and Schmidt, 2015).In 2015 Earth Economics was commissioned by Nautilus Minerals Inc to conduct an independent, objective environmental and social benchmarking analysis of the proposed deep seabed Solwara 1 mine with terrestrial copper mines (referred to as ‘the report’). The report represents the first ever natural capital accounting and ecosystem goods and services framework for seabed mining.The report compares the proposed Solwara 1 mine with three terrestrial mines: Bingham Canyon (Utah, USA), Prominent Hill (South Australia, Australia), and Intag (a proposed mine in Intag Province, Ecuador), and provides a natural capital accounting assessment for all four operations.CITATION:Grogan, R, 2016. Natural capital accounting – a sea floor mining application, in Proceedings Life-of-Mine 2016 Conference, pp 2–4 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Bluhm S. J, Feio L, Ramsden R

A new mining area at the Vaal Reefs gold mine is to have a shaft. system which will extend to a depth of 4 200 m and will require 130 MW of cooling. A novel feature of the proposed cooling system is a large underground air cooling installation in which an ice slurry is sprayed into the ventilation air. The design of the ice slurry bulk air cooler, in the form of counter.flow cooling towers, is discussed. Comparative thermal tests with cold water and ice slurries (with ice mass fractions up to 22 per cent), were carried out in a 5 m high test tower. The presence of the ice in the water spray increases the resistance to heat flow and reduces the overall thermal characteristics of the air cooler by 8 per cent. Notwithstanding this, the use of ice slurries is indeed beneficial in terms of overall costs. It is concluded that a 25 MW air cooler should use 410 kg/s of ice slurry with a 10 per cent ice mass fraction to cool 550 kg/s of air which is 75 per cent of the total air flow rate.

Jan 1, 1988

By Williams D. J

The boundary element method is one of a number of tools that have found wide application in geomechanics for mine design and stress analysis. Two examples are presented in this paper, illustrating the use of the boundary element method to find potential problem regions in large-scale excavations. These examples are from a Papua New Guinea open cut mine and an Australian sub-level caving operation. Because of the scale of the mines and the complexity of the excavations, the boundary element method is the only practical numerical modelling technique to account for the major influences. Although the boundary element method uses only linear elastic models of the rock mass, the paper illustrates techniques for dealing with non-homogenous and anisotropic rock masses, as well as clasto-plastic effects associated with an excavation.

Jan 1, 1995

The aim of the study was to determine the ranges of stability and instability of the metal hydroxides and metal cyanide species that may be formed during the gold extraction process, Merrill-Crowe gold precipitation, and Inco S02/Air or ferrous ion cyanide removal processes.Following cyanide detoxification by the Inco S02/Air process, the main components of concern in the tailings will be:

Jan 1, 1997

By Fewings JH

When the mining and milling of 1100 Copper Orebody commenced, difficulties were experienced in producing a satisfactory grade of copper concentrate. The major concentrate contaminants were fine pyrite and silica, particularly in the minus 10 microns fraction. Studies of the 1100 Orebody showed that much of the fine grained pyrite and a proportion of the silica present in the ore contained carbonaceous matter in the form of complete or partial rims and as internal carbon films disseminated throughout grains. The hydrophobic surface property of the carbonaceous material resulted in an inherently flotable fine pyrite and silica fraction. The addition of a 60:40 mixture of nigrosine and dextrine, initially to a prefloat concentrate of the inherently flotable carbonaceous material and finally to'the total copper flotation feed, successfully controlled the flotation rates of the carbonaceous pyrite and silica. The objective of a 25 per cent Cu concentrate grade was then achieved without decreasing copper recovery.

Jan 1, 1970

By Keys NJ

The so-called COMAT process provides a method for leaching low grade sulphide mattes in an acidic ferric sulphate medium in such a way that non ferrous base metals such as Ni,Cu and Co are substantially all dissolved; the concentration of residual acid and dissolved iron remaining in the leaching solution is low, and a large portion of the sulphide sulphur is converted to elemental sulphur. Thus the quantity of neutralising agents required to remove residual acid and dissolved iron from the leach solution prior to subsequent recovery of the dissolved base metals is greatly reduced. The leach residue and iron precip- itate report in a readily filterable form. In this paper results obtained on a pilot plant scale are presented for the leaching of a typical low grade matte in the manner describ- ed above; for the solvent extraction and elec- trowinning of copper, and for the removal of residual acid, copper and iron from the copper solvent extraction raffinate. Processes tested on a laboratory scale for the further recovery of cobalt and nickel by solvent extraction and electrowinning, and for the recovery of sulphuric acid and ammonium hydr- oxide from the dissolved ammonium sulphate salt contained in the final plant effluent, are also briefly described.

Jan 1, 1986

By H Ramandi, H Masoumi, I Canbulat, B Hebblewhite, J Oh, S Saydam, W Timms, S Mo

This paper reviews the floor heave mechanisms in underground coal mine roadways. Previous studies have reported three main failure mechanisms: bearing capacity failure, buckling and swelling. The buckling failure has been observed where immediate floor strata are relatively strong and thinly bedded. On the contrary, the weak floor strata have been associated with both the bearing capacity failure and swelling mechanisms. The bearing capacity floor failures are likely to induce other types of instability such as pillar punching, tensile failure of pillar, roof fall and subsidence as well as floor heave. Despite a considerable amount of research, predicting the magnitude, location and timing of floor deformation is challenging with current state of knowledge. CITATION:Mo, S, Ramandi, H, Oh, J, Masoumi, H, Timms, W, Canbulat, I, Hebblewhite, B and Saydam, S, 2018. A review of floor heave mechanisms in underground coal mine roadways, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 196–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

The able address on the currency question given by the Right Honorable A. J. Balfour, M.P., late leader of the Government, at the Mansion House lately, before a large and influential audience, will strike a key-note that will resound throughout the world. It is high time that gentlemen of position and influence should come forward and express their views on this subject, so as to cause the matter to be,more seriously considered than it has been. The question can be no longer ignored or treated with indifference by bankers, financiers, merchants, miners, and others interested in the settlment on some basis the relative values gold and silver bear to each other. It is gratifying to not that such a great leader of political opinion as Mr. Balfour has given serious attention to this important question.The address created a deep impression ,on the minds of many who probably had not given the matter much att.ention, and Mr. Balfour's words will re-echo over a wide range of thought with such effect that I have no doubt they will materially help to check the downward tendency of the value and uses of silver. As a mining engineer, interested in the development of our mining resources for increasing gold aud silver for currency, and having devoted much attention to the subject, I cordially approve of the views set forth by Mr. Balfouf, and I think the general body of all interested in the production of gold and silver will do the same.

By Higuchi K, Sekimoto Y

In this report,the results of the large diameter drilling tests in coal seams assisted with water jet are described. The stress relief in coal seams by this new method is as effective as by the conventional method and the penetration speed by this method is 1.5 times as fast as by the other method. 1 Introduction The average mining depth of Japanese coal mines has already attained about 700m from the surface. Almost all coal mines are suffered from occurrence of coal and gas outbursts. To prevent outbursts, some countermeasures are taken generally. In particular, large diameter stress relief borings have been carried out quite often at Akabira coal mine located in the northern part of the Ishikari coal field in Hokkaido,JAPAN. These borings have had successful results but the drilling work of such large diameter

Jan 1, 1987

The issue of retrenchment is a topic of considerable relevance for the Papua New Guinea (PNG) mining, petroleum and gas industries. The unique environments in which Porgera Joint Venture (PJV) and other similar operations operate are likely to confront these industries with particular dilemmas that will require a range of investments to mitigate the problems associated with retrenchment and employment. This paper discusses retrenchment and employment in the PNG mining industry using the specific case study of PJV. The paper deals with the issue of employment and retrenchment of local workforces in the PNG context, which presents a serious challenge for the resources industry and the achievement of sustainable development objectives. The issue of future retrenchment of the workforce as a result of mine closure is an obvious challenge for both PJV and the Porgeran community at large, who have now come to rely upon both the employment opportunities presented through the mining. This paper examines these challenges and in doing so highlights some progress made by PJV. The paper also discusses downsizing, strategic practices and holistic approaches of retrenchment and employment. In doing so the paper highlights issues that have been overlooked in both academic and applied studies from global and local perspectives in the PNG mining sector. The latter sections articulate the relevance of the information provided by the case study in the wider context of retrenchment. The conclusion promotes a perspective that a great deal more investment will be required by all stakeholders to respond to the challenges of managing retrenchments and mine closure.

Jan 1, 2009

The geotechnical and environmental aspects of heap leaching are very closely tied during design, operations and closure. Potential environmental impacts from heap leaching are mostly due to land disturbance and water quality issues, including both groundwater and surface water. Water quality issues are mostly related to containment design, which is primarily a function of proper sizing of the facilities and site specific liner design. Geotechnical analyses is the dominant discipline in providing cost efficient, operationally effective and environmentally sound heap leach facility designs. Much has been published on geotechnical aspects of heap leach design, for example Van Zyl, Hutchison and Kiel (1988) and Van Zyl (1987). This paper will emphasize a few specific aspects related to the geotechnical and environmental consideration for heap leach projects. These aspects are: ò site investigation; ò containment design; ò slope stability; ò heap flow dynamics; and ò closure design. Design of a heap leach project must consider not only the operating life but also closure and post-closure considerations. As a matter of standard practice, designing for closure is an extremely important concept. Not only is it important for environmental aspects, but experience also shows that projects designed for closure will be overall more economical for the total life cycle of the project. Closure considerations are also important during project feasibility evaluations to ensure that total life cycle costs are evaluated.

Jan 1, 1994

North Eastern Russia encompasses the northern part of the Circum Pacific. The region comprises various tectonostratigraphic terranes, including cratonic blocks, fragments of volcanic arcs, accretionary wedge terranes, oceanic crust and passive continental margins. The terranes have been accreted to the eastern margin of the Siberian Craton in the Late Mesozoic. The prominent structures of the region are extended zones of the Mesozoic flysch and turbidites. Another important structure is the 3000 km long Okhotsk-Chukotka volcanic arc which marks the Cretaceous active continental margin of northern Eurasia. The youngest structure of the region is the 2000 km long Late Cainozoic Kamchatka-Kuril island arc system. North Eastern Russia is the main gold producing region of the Russian Federation. Since the beginning of recorded gold production in 1932 until 1995 the region has produced 2575 t (83M oz) of gold. Most of it, 2439.5 t, has been produced from placers. Owing to depletion of alluvial gold resources, exploration and mining emphasis is currently switching to the development of the lode deposits. At least five distinct types of the gold mineralisation are reported in North Eastern Russia - mesothermal gold mineralisation in the Mesozoic fold belts, Paleozoic epithermal gold mineralisation occurring within Omolon block, epithermal gold mineralisation related to the Mesozoic volcanics, Cainozoic epithermal gold mineralisation, gold-bearing Cu-porphyry deposits. The current paper introduces the metallogeny of lode-gold deposits of North Eastern Russia. It provides the review of the regional geology, the selected gold provinces and representative deposits with an emphasis on the mineralisation styles and distribution control.

Jan 1, 1999

Mt. Whaleback, the property of the Mt. Newman Joint Venturers, contains more than one thousand million long tons of high grade hema- tite averaging 64% Fe, ranging from 70%, the grade of absolutely pure hematite, to 54%. The ore occurs in the Dales Gorge and Joffre Members of the Brockman Iron Formation. The interbedded shale bands common in other orebodies occurring in these horizons are seldom more than a few inches thick and are commonly partially enriched to about-35% Fe. In the generally hard, massive hematite orebody, the gangue minerals tend to break preferentially to the fines, or -6 mm product, and for this reason it is of a somewhat lower grade than the lumpy product. The control of the chemical qualities is concentrated on the fines product for it has been found that maintaining the iron and alumina levels in this product ensures that all chemical specifications are met in both the lump and fines products. Physical qualities are monitored to ensure that the physical quali- ties of decrepitation and degradation of the lumpy product are maintained at levels accept able to the buyers.

Jan 1, 1973

By Eyers G. C

Long Shaft was initially developed using a rail haulage system on every working level comprising battery electric locomotives and granby trucks loaded by rail mounted rocker shovels. Production was commenced using conventional hand held cut and fill mining methods. In an effort to improve productivity and reduce operating costs a mechanised cut and fill stoping method evolved to suit the wider sections of the orebody. To further improve productivity and reduce costs the mechanised levels of the mine are progressively being redeveloped to enable the use of trackless diesel haulage equipment. An added benefit of trackless haulage equipment will be the ability to place development mullock into stopes as Fill.

Jan 1, 1988

A new watersoluble binder for mineral ore pellets has been developed by the sulfonation of bituminous materials. A highly effective binder for iron ore pellet making is obtainable from bituminous materials produced in the hightemperature cracking of crude oils. This paper deals with production process and basic properties of this binder as well as new applications in the field of iron ore pelletizing.

Jan 1, 1974