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By E. A. Brocchi, P. K. Jena

Complete extraction of copper from Salobo chalcopyrite concentrate can be achieved in less than 10 minutes by chlorination of the dry concentrate with Cl2 at 450 degrees C and in 5 minutes by chlorination of an aqueous slurry containing 5 wt% concentrate at 30 degrees C. In general, slurry chlorination appears to be faster than dry chlorination. The kinetics of dry chlorination of copper sulphide are controlled by an adsorption mechanism with an activation energy of 6.1 kcal/mole. The rate is independent of chlorine partial pressure when pCl2 exceeds 0.4 atm. In slurry chlorination the dissolution of copper sulphide follows a topochemical reaction model and the rate of chlorination decreases with increase in pulp density and also temperature. Dissolved chlorine appears to take part in the reaction in atomic or ionic form.

Jan 4, 1992

By G. B. Hooper, G. A. Ferguson

The technical capabilities and user-friendliness of the major computer-aided mining design software systems are reviewed. Recent experiences with three systems are outlined to indicate the practical problems that arise. The examples were: Microlynx software from Lynx Geosystems at the Great Dyke platinum mine in Zimbabwe; Lynx software from Lynx Geosystems at a copper mine in central Africa; and PC-MINE software from Gemcom Services at an open-pit gold project in Western Australia. Difficulties in the use of mining design software has led to an alternative approach. Falconbridge, Canada, has developed an integrated mine-planning system on a CAD platform that encompasses ore reserve estimation, stope design, development layout and survey control. Future directions of computer-aided mining design using this basis are discussed. A major advantage of using mainstream software packages, such as spreadsheets, databases and CAD programs, is that most engineers and geologists are experienced in handling such systems in the normal course of their work.

Jan 12, 1992

By M. D. Pritzker

Shrinking-core models are used to describe the physico-chemical processes that are associated with many metallurgical gas-solid and liquid-solid reactions. The models can be used to evaluate rate constants and effective diffusion coefficients from experimental data. This work generalises the model for diffusion through a product layer to cases where the transport of more than one species is rate-controlling

Jul 1, 1991

By P. Danson, D. A. White, S. Bashir

Composite ion exchange materials made of SnO2, TiO2 and MnO2 can be used to remove radioactive contaminants from nuclear waste streams. In several cases their selectivity and capacity are enhanced by mixing hydrous silica into the matrix. MnO2-SiO2 materials are especially useful for a number of reasons, such as their selection of heavy elements over caesium. Distribution constants and determinations of exchange capacities show that in many instances the properties of the composites are better than those of the oxides alone, while the presence of a chelating agent has been found to reduce the uptake of nuclides considerably. Methods are being developed for the bulk manufacture of the materials. Further work on sorption mechanisms is required to explain anomalous results, particularly the variation in exchange capacity for different elements and the ability of the oxides to sorb colloidal material in alkaline solution.

Jan 8, 1992

By NA NA

Listing safety award winners, £I43M has been added to proceeds from coal privatisation in the year to March 1997, bringing total revenues to over £1.3bn, some company news in brief.

Jan 8, 1997

By Ruddle R. W.

An outline account is given of the smelting of copper and the chemistry of the process. A table provides compositions of the more important minerals from which copper is won by smelting. Roasting is discussed as is smelting using reverberatory furnaces, blast furnaces and flash smelting. A brief discussion of converting covers the upright (Great Falls) converter and the horizontal (Peirce-Smith) converter.

Jan 1, 1953

By Ruddle R. W.

The slags produced in copper smelting are largely composed of silica and ferrous oxide and may therefore be regarded as essentially ferrous silicates. A fair amount of information is available on the constitutions of the liquid slags used in copper smelting and, in this connection, the large volume of work being carried out on steelmaking slags should be helpful. Constitutional diagrams are available for most of the principal systems involved (SiO2-FeO; SiO2-FeO-Al2O 3; SiO2-FeO-CaO; SiO2-FeO- MgO; and SiO2-FeO-CaO-Al2O3) and these show that additions of Al2O3 and CaO reduce the freezing points of SiO2-FeO slags but that additions of MgO increase the freezing point. A certain amount of information is available on the thermodynamics of slags, but much further work on this subject is required. Modern theories of the constitution of liquid slags deny the existence of molecular compounds but consider that liquid slags are mixtures of various ions such as, Fe2+. O2- and SiO4(4-). Little appears to be known of the reactions between matte and minor constituents dissolved in the slag

Jan 1, 1953

By Emanuel Shinwell, Douglas Hay

"Opening statements relating to the health and welfare of underground workers and the nature and prevention of silicosis and pneumokoniosis. During 1945-47, 10,500 UK coal-miners were certified by the Silicosis Medical Board to be suffering from pneumokoniosis and suspended from work in the industry. Over 80% of cases occurred in the South Wales coalfields. Silicosis and pneumokoniosis also occur among metalliferous miners, such as the tin-miners of Cornwall. The slate-quarries of North Wales are also troubled by these conditions as are the haematite mines of the North-West of England."

Jan 1, 1947

By M. Thompson, B. Coles, M. Hale

The use in regional geochemical reconnaissance of replicate analysis of natural coatings of iron and manganese oxides on the surface of pebbles in stream sediment is described. Pebble coatings were selectively analysed for their relative contents of absorbed trace elements by ablating a small quantity of the coating with a laser beam and sweeping the aerosol obtained into an inductively coupled plasma atomic emission spectrometer. Using this procedure, a geochemical survey in northwest Wales revealed anomalous concentrations of Cu, Mo, As, Zn, Cd, Pb and Co in the pebble coatings of streams draining the mineralised Coed-y-Brenin diorite and the Dolgellau gold belt.

Jan 4, 1992

Discussion of the paper presented at the Manchester Geological and Mining Society's general meeting held in Manchester, April 11th 1916, with Mr. Leonard R. Fletcher, President, in the chair, included questions asked and points for discussion raised by Bramall V., Paton J.D., Fletcher L.R., Siddall F.N., Stoker A. and Stone T., in particular on how to eliminate dust

Dec 1, 1916

By J. A. Franklin, E. Broch, G. Walton

To make the best use of rock core, the mechanical character of the rock should be evaluated concurrently with conventional geological observations. The advent of simple techniques, such as the point load 'nutcracker' test, makes field logging of mechanical properties competitive with sampling and testing in the laboratory

Dec 1, 1971

By Winmill T. F.

Among the various theories proposed to account for the spontaneous ignjtion of coal, one which has at times been very strongly held is that the initial heating is due to the oxidation of iron pyrites. From the results described in this paper, it is possible to calculate roughly the rate of spontaneous heating of a specimen of finely-divided pyrites, on the assumption that all the heat developed is used in raising the temperature of the pyrites, and that none is lost. It is clear that where finely-divided pyrites occurs in considerable proportion among coal, it may be the chief factor in originating combustion, but that pyrites can only be the cause of a heating when it is present in considerable proportion, and in a very finely-divided state

Dec 1, 1916

By J. Gough M. D.

There are many points still obscure regarding the nature of coal-workers'- pneumokoniosis, but the interpretation of the disease has been greatly clarified in recent years. It is now known that exposure to fumes or gases or other conditions peculiar to coal-mining are not necessary factors in the production of pneumokoniosis. The same disease occurs in coal-trimmers working in the docks, and it is thus established that the inhaled dust is the primary factor. On the other hand, there is no completely satisfactory explanation of the distribution of the disease. Geological and petrological studies have not given an unequivocal explanation of the difference in incidence in different parts of the coalfield. It is an open question whether the quantity of dust inhaled is more important than its chemical composition. However, there is ample evidence from the medical side that elimination of dust and of tuberculosis from the environment of coal workers will be required to prevent pneumokoniosis. Much is being done with regard to elimination of dust, and a similar energetic action is required in regard to tuberculosis.

Jan 1, 1947

By L. R. Chimimba

"The Trojan nickel deposit occurs within a pile of ultramafic lavas subjected to a lower amphibolite grade of metamorphism. The lavas form part of the Upper Greenstones (Bulawayan Group) of the Mazoe greenstone belt. The nickel mineralization occurs as disseminated, massive and near-massive sulphides. The massive and near-massive ore occurs along the basal contact of the serpentinite units and is overlain by the more abundant disseminated ore, which occurs within the serpentinite. The main sulphide minerals are pyrrhotite. pentlandite and chalcopvrite. Minor amounts of millerite and pvrite are present. The Ni : Cu ratio in all three types of ore averages 15:1.The intercumulus nature of sulphides in the near-massive ore and similar textures occasionally seen in the disseminated ore indicates a magmatic origin of the mineralization. The basal position of the near-massive and massive ore suggests that the sul­ phides settled out under gravity during the emplacement and crystallization of a peridotitic magma. The deposit has been deformed and some of the primary massive ore has been remobilized into veins and breccias. The disseminated mineralization now occurs mainly as blebs of sulphides intergrown with silicate minerals or as stringers of sulphides between foliation planes in the serpentinite."

Jan 1, 1984

By Black J.

Further discussion at the Mining Institute of Scotland's general meeting held in Edinburgh, 12 February 1916, with D.W. Mowat, president, in the chair, of a paper published in Trans. Inst. Min. Engrs., 1915, vol. L, p.449 included written contributions by Dron R.W., Riddell W., Hamilton J. and Mowat D.W.

Dec 1, 1916

By R. Vikram

IMAGES (Integrated Mapping Applications Graphical Evaluation System) is a computer graphics system developed by British Coal for mine planning. The objectives of the system are to increase the profitability of mined coal through a combination of direct and indirect benefits. The system is flexible and can be used in part or in full at a mine as a stand-alone system or as a remote location of a central corporate system.

Jan 12, 1992

By J A. Hacked

This paper explores the potential to exploit controls over the outputs of the primary blasting operation, arising from the performance consistency benefits gained in using modern bulk emulsion explosives technology. The former, allied with the latest powerful blast predictive software and measuring tools, offers the user the opportunity to apply control over both cost and performance, which has not been possible in the past.

Jan 12, 1997

By P A. Collier

The general view of the author is that all the good intentions of manufacturers can fail completely if the variations in circumstances in underground mining are not considered at all times. With a belief that it is the customer that has the experience and know ledge of problems which occur on long installations. Reilloc talk with customers in coal mines around the world, and have done so from their inception. With considerable experience in their home market, their technical approach was received with enthusiasm by coal companies in both Australia and South Africa, and whilst experience was obtained in other countries, it is the particularly close working relationship in these two areas that is covered in this paper. The refinement of manufacturing techniques and the fine tuning of the specification to which the chain is made was developed in conjunction with factual underground experience obtained by customers as they sought to improve their productivity and a reduction in working costs. With a reliable product the mines are able to concentrate on improved operational techniques to extend the useful working life and plan for multi-panel usage of the chain.

Jan 5, 1996

By D. J. Fray, F. Tailoka

Microporous ceramic tubes (15 micrometre pore diameter) and PVC membranes (10 micrometre diameter) have been used as spargers in the electrowinning of copper from concentrated and dilute chloride electrolytes. At a current density of 600 A/m2 and a nitrogen gas sparging flow rate (at NTP) of 1.53 cm3/s per unit electrode length, it was possible to electrowin planar rather than powdery deposits with copper concentrations as low as 0.157 M. To obtain a planar deposit at higher concentrations of cupric chloride the most realistic optimum current density appears to be between 1 000 and 1 500 A/m2.

Jan 4, 1993

By W. J. Whiten, D. W. Grinsberg

Most cluster analysis techniques are not well suited to the analysis of engineering data as they have been designed for more qualitative data that tend to produce compact clusters. A clustering technique is described which develops and uses local cluster shapes to build clusters that are suitable for use in engineering applications. The technique is finding application in the analysis of many types of data, particularly where multiple trends and outlying points occur in multiple dimensions. Applications of particular interest are the calibration of on-stream analytical equipment and the analysis of data on plant performance. In both cases the multidimensional nature of the data renders manual analysis very difficult

Dec 1, 1991