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By D. R. Hudson, M. J. Donaldson

"Study of gravity concentrates from the gold-recovery circuit of the Kambalda nickel mill has enabled an assessment to be made of the nature, relative abundance and compositional variability of platinum group element (PGE) minerals and other associated heavy minerals that are present in the Kambalda nickel deposits. The major platinum minerals are sperrylite, PtAs2, and nioncheite, (Pt. Pd, Ni)(Te, Bi)2, and the major palladium minerals are sudburvite, (Pd, Pt, Ni)(Sb, Te, Bi), stibiopalladinite, Pd6Sb2, and palladoarsenide, Pd2 (As, Sb), together with a palladium antimonide and a palladium arsenide that have not been fully characterized. Palladian melonites, which contain up to 10 wt% Pd, and palladian nickeline are also important PGE hosts. Sperrylite and sudburyite are by far the most abundant discrete minerals in the gravity concentrates.Gold occurs as argentian, cuprian and nickeloan—cuprian gold, and as the tellurides calaverite, petzite and auriferous hessite. Silver is present in petzite, hessite and volynskite. Other rare phases contained in the gravity concentrates include native bismuth, altaite, frohbergite, breithauptite, gersdorffite, parkerite, scheelite, tantalite, cassiterite, rutile, bunsenite, gahnite, barite and uvarovite.Descriptions of in-situ occurrences of PGE minerals at Kambalda are rare. Michenerite, PdBiTe, and testibiopalladite, PdSbTe, have been described from a telluride-rich quartz-carbonate vein that intersects massive sulphide ore in Lunnon Shoot. Moncheite has been observed in chalcopyrite-rich stringers, and sudburyite occurs as inclusions in nickeline in a quartz- carbonate veinlet. No discrete PGE minerals have been found within the massive and matrix ore zones in the Kambalda ore- shoots, and the geochemical distribution of PGE suggests that the formation of discrete PGE phases may be related to post- magmatic processes—in particular, metamorphic segregation of sulphides, and the interaction of the ore sulphides, containing PGE in solid solution, with younger hydrothermal fluids. This has led to local redistribution of the PGE, with concentration in footwall stringers and veins, and in reaction zones."

Jan 1, 1984

By R. J. Howarth, P. L. Llowenstein

The errors resulting from field sampling, sample preparation and analysis are investigated for drainage sediments derived from homogeneous sandstone, shale, limestone, basic igneous and granite lithologies as a background to a primary reconnaissance survey of England and Wales. Emission spectrographic analyses of approximately 350 samples for Al, Ca, Fe, K, Si, Ba, Co, Cr, Cu, Ga, Li, Mn, Ni, Pb, Sc, Sn, Sr and V and atomic absorption analyses for Cu, Ni, Mn, Co, Zn and Pb have been treated statistically. For routine broad-scale surveys analysis of the unground -80-mesh sediment fraction proves satisfactory. Sampling error between localities in a stream is shown to be less than spectrographic analytical error for many of the elements considered here, except where mineralisation (contamination) occurs, but exceeds the atomic absorption analytical errors in most cases. Unless it it critical to reduce the amount of between-site variability (having regard to analytical errors) in the regional survey, there appears to be no advantage in the use of a more sophisticated sampling technique. The utility of moving-average maps in reducing the width of the confidence belt around the regional 'geochemical surface', and thus compensating to some extent for the sampling errors, is also demonstrated.

Dec 1, 1971

By A. R. Biggart

Twenty-sixth Sir Julius Wernher memorial lecture, presented at the Tunnelling '94 symposium held in London, 5-7 July 1994. In describing 18 projects with which he has been involved over a period of 36 years, the author aims to illustrate how technological change and an increase in scientific knowledge have influenced tunnelling practice, which he nevertheless maintains does continue to be an art. Tunnels discussed are: the Silver Street, Blackfriars, Whitechapel, St. Paul's and Waterloo Post Office tunnels, 1958-1969; metro tunnels on the Victoria Line, London, 1962-1970; the introduction of tunnel boring machines (TBMs), 1971-1978, in the Empingham reservoir diversion tunnels in Rutland, the bentonite tunnelling machine experiment at New Cross, the Southern tunnel water main section of the London Ring Main and the Warrington sewer in Cheshire; tunnels in rock 1975-1981, for the Lune Wyre and Megget Manor aquaducts, Weymouth sea outfall and Bristol interceptor sewer; Priestley TBM tunnels 1969-1982; the Greater Cairo wastewater project 1983-1987; Anacostia River crossing, Washington DC 1985-1987; the Channel Tunnel 1987-1992; and the Storebaelt eastern tunnel in Denmark, 1992-1994.

Dec 1, 1994

By D. C. Yates, G. V. Jolliffe

In the five coalfields of Staffordshire, there have been some 43 incidents of spontaneous fires and heatings which have required special attention in the past ten years. This total excludes incidents in the Thick Coal Seam of South Staffordshire, which was worked until 1967, and which was subject to an almost continuous series of heatings. The incidents have been classified to show the sites of occurrence, the contributory factors which may have caused them and the treatments applied to them. The remedial techniques, as practised in Staffordshire, are dealt with in detail, with particular reference to standard methods of stopping-off. Precautionary measures taken are described, including a "liability to spontaneous combustion" classification of all seams, and the setting up of an emergency organization with emergency stocks of materials and equipment. The paper is concluded by a few words on the organization and control at the time of an incident.

May 23, 1905

By M. J. Howes

The high degree of mechanisation, which is mainly diesel-powered, has a significant effect on heat loads; heat output from this source often exceeds the heat flow from the surrounding rock. The extensive use of diesel-powered equipment also influences ventilation rates and minimum values are necessary to ensure that emissions of diesel exhaust are adequately diluted. Many Australian mines are in subtropical or tropical areas with high ambient wet- and dry-bulb temperatures on surface. This, coupled with the large amount of heat from mechanisation, usually means that refrigeration is required at much shallower depths. A secondary problem is associated with the definition of acceptable thermal environment conditions, which are sometimes based on the assumption of no air movement. This gives rise to very stringent thermal environment acceptance criteria, which, in some areas, would prohibit work on surface, let alone underground

Jun 12, 1905

By ed. comp., S. H. White, A. J. Naldrett, P. R. Simpson

Peter Simpson's introduction, Tony Naldrett's concluding remarks and discussion by Prof. White of D.M.A. Flight's report of the proceedings are presented from the conference held in Keyworth, UK, in April 1992

Apr 1, 1995

By J. Cech

Discussion is presented of a decision-making support method for the spacing of ore passes along a long vein orebody and the division of the orebody into convenient stopes for future mining operations. The method was tested on a Slovak siderite deposit and also on some hypothetical cases with the objective of obtaining more general results

Jun 18, 1905

By Thomas D. E.

Discussion at the Manchester Geological and Mining Society' general meeting held in Manchester, March 14th , 1916, with Leonard R. Fletcher, President, in the Chair, of a paper published in Trans. Instn. Min. Engrs., 1916, vol. L., page 482, comprised the author's written response to suggestions made in previous discussion

Dec 1, 1916

By D. V. Venugopal, W. W. Gardiner

Spessartine-quartz rocks are manganiferous sedimentary rocks rich in spessartine and quartz which occur in north-central New Brunswick. They represent a recrystallised manganiferous siltstone/chert that is contained in or associated with red manganiferous siltstone (RMS) units. The spessartine-quartz rocks and RMS form part of an Ordovician volcanic and sedimentary succession within the Appalachian-Caledonian orogen which hosts numerous massive sulphides and polymetallic vein deposits. The New Brunswick spessartine-quartz rocks are spatially and temporally associated with stratiform base-metal, precious metal and hydrothermal tin-tungsten deposits. This suggests that spessartine-bearing lithologies and zones can be useful in predictive metallogeny and for the understanding of the stratigraphy and palaeographic setting of the early Palaeozoic rocks of the Appalachian-Caledonian orogen.

Jan 12, 1992

By W. P. C. Duyvesteyn, B. J. Sabacky

Reprinted with revisions from Extractive metallurgy of copper, nickel and cobalt, volume I: Fundamental aspects. ed. Reddy R.G., Weizenbach R.N. Warrendale, Pennsylvania: The Minerals, Metals and Materials Society, 1993. Development work on the Escondida process, concluding with the successful operation of an integrated leach-SX-EW pilot plant and a pilot flotation plant for the upgrading of leach residues, demonstrated that all major process objectives could be achieved. Extraction of 40% of copper in concentrates containing monovalent copper was achieved with essentially no oxidation of sulphide sulphur. The Cu contents of leach residues from four different types of concentrate were successfully upgraded to the original feed grades, giving a product that has potential as a high-quality concentrate for the smelter market. A compact solvent extraction section effectively recovered the ammonia lixiviant for recycling to leaching and selectively transferred Cu into a conventional acid sulphate electrowinning system. High-quality "six-nines" copper cathode was produced on commercial-scale stainless steel blanks, demonstrating that the process will be able to compete effectively in the premium cathode market

Dec 1, 1995

By J. Plant

Stream-sediment sampling undertaken to define the regional geochemistry of northern Scotland is described with particular reference to the errors involved. The region is underlain essentially by Moine schists, Caledonian granites and Old Red Sandstone sediments, which are generally characterized by low geochemical relief. Factors in the secondary environment obscure the relationship between trace-metal concentrations in stream sediments and bedrock geology. Investigation of sampling and sample preparation methods indicates that the -100-mesh material is the optimum size fraction for the regional survey of this area: it provides adequate geochemical contrast: it reduced the incidence of spurious high values in the samples investigated and it is available in amounts which are adequate for all the analyses required. Grinding samples improves precision and reduces the preferential volatilisation of metals coprecipitated with hydrous manganese and iron oxides for the optical emission spectroscopic method used initially. A study of the dispersion of metals in the drainage system of an area of Pb-Ba-Mo mineralisation and an area of U-Pb mineralisation, respectively, indicates that a sampling interval of 1 per 2 km2 based on second- or third-order streams is adequate to define anomalous metal concentrations. Regional variation can also be represented on the same interval. Modifications to the sampling procedure to reduce the effects of the secondary environment are complicated by the primary association of Mn and Fe with mineralisation in the area. The ratio of analytical and sampling error to regional variance shows that procedural precision is adequate to prepare regional geochemical maps of northern Scotland, with the exception of Cr, Cu at low concentrations and Pb.

Dec 1, 1971

By B. Denby

sintered ores, to be removed by a pneumatic,

Apr 1, 1995

By Tawsaporn Nuchanong, Ian Nichol

Investigations of the dispersion of gold in soils and stream sediments associated with three gold deposits in Thailand indicate the existence of different geochemical dispersion patterns in the three areas, demonstrating the need for the adoption of a variety of exploration techniques. The three gold deposits which were investigated were the Phu Tham Phra-Phu Thong Daeng copper-gold prospect, the Doi Tung and the Huai Hin Lab gold prospects. Overall the investigations at the three localities demonstrate clearly that the chances of exploration success can be significantly enhanced if composite soil samples are analysed to ensure a more reliable estimation of the gold content in soils and if both the 63 micrometre fraction and the field-panned concentrates of stream sediments are analysed because of the variable grain size of the gold characterising different gold deposits and surface environments.

Jan 4, 1992

By L. J. Cabri

Although no complete mineralogical balances have been published, the background knowledge and proven, highly sensitive analytical techniques to produce them already exist. For PGE-Cu-Ni sulphide ores a combination of ore microscopy, image analysis and electron microprobe analysis with proton microprobe analysis of sulphides for Pd, Rh and Ru and ion microprobe analysis for Pt, Ir and Rh (in some minerals) should provide the necessary data when combined with reliable assays. Other sulphide ores, such as the Cu-Ni-(PGE) ores of Sudbury, Ontario, require a similar approach except that the ion microprobe would be more suitable for the analysis of Pd, Pt and Rh because of its greater sensitivity. Oxide-silicate ores may be harder to deal with quantitatively, although the potential to confirm the presence of trace PGE within silicates and oxides may be greater than in PGE sulphide and Cu-Ni-(PGE) sulphide ores. However, solid solution of PGE in oxides and silicates still requires thorough documentation and evaluation in terms of their significance for the overall metallurgical balance

Apr 1, 1994

By R. R. Tatiya

The following procedure was used to determine cut-off grades: define the orebody profile; plan the stope layout and quantify the work involved; formulate equipment-performance norms; calculate unit costs; input process recoveries and metal prices; and calculate the cut-off grade. Use of the method is illustrated using data from a copper mining complex in India. Results from the study led to the following conclusions for underground mines in general. Cut-off dependent costs vary significantly with the stoping method employed, orebody thickness, the degree of mechanisation and the working efficiencies of the workforce and equipment. This applies even within the same deposit. Sub-level stoping and its variants can be operated at a lower cut-off grade than cut-and-fill and its variants. Thinner orebodies affect cut-off grades adversely, but with thinner orebodies very little further reduction in cut-off grade can be achieved once a certain minimum width has been exceeded. For the same stoping method and in the same mine the cut-off grade varies with the degree of mechanisation. Labour-intensive methods require higher cut-off grades. An allowance for working efficiency should be made when calculating cut-off grades. Higher process recoveries allow a significant lowering of cut-off grades

Jul 1, 1996

By N. A. Warner, R. K. Manna

Physical modelling of liquid-phase oxygen mass transfer in a water model of part of a proposed new polymetallic smelter has been achieved. A study of solute mass transfer caused by multiple, subsonic air jets contacting superoxygenated water flowing in a channel model of the smelter converting hearth has been carried out. For a wide range of channel flow rates the rate of mass transfer was found to be independent of water velocity. The water model has been used to compare mass transfer for both open-packed and close-packed multiple-lance arrays with circular nozzles of diameters 2.26, 4.95, 10.95 and 24.40 mm. It was found that with fewer of the larger-diameter nozzles a reduction of up to 58% in liquid-phase mass transfer occurred, especially for the close-packed lance configurations. This restriction of liquid-phase mass transfer would result in reduced metal losses in the analogous smelting situation. The larger nozzles, however, exhibited more jet-jet and jet-channel wall interference effects than their smaller counterparts, resulting in an effective reduction in the momentum fluxes of the impinging jets

Jul 1, 1991

By P. Varona, L. Lorig, M. Board, E. Chacon

Geomechanical factors at the mine are important and will become even more relevant as the pit expands and deepens. To address these demands a team was assembled to collect geomechanical information and perform numerical analysis. The west wall is the largest and flattest of all the design sectors in the pit and rigorous studies were carried out on this wall. The wall behaviour is controlled mainly by a set of steeply dipping joints within the slope in the Fortuna Granodiorite and a weak zone, the Zona Plastica, that extends vertically near the pit bottom. These features lead to large toppling displacements in the upper portions of the wall. Two numerical models were used to reproduce the general features of failure observed in the wall. The modelling indicated that a toppling mode of failure results from shear on the steeply dipping joints. The toppling leads to slumping or landslides whereby the west wall flows slowly downslope as the Zona Plastica compresses

Apr 1, 1996

By D. J. Esdale, D. F. Pridmore, F. W. Lindman, J. H. Coggon

Almost all the presently viable nickel reserves in the Yilgarn Block contain nickel in a sulphide phase. Both volcanic peridotite- associated (VPA) deposits and intrusive dunite-associated (IDA) deposits are characterized by massive, matrix and disseminated sulphides (typically, pyrrhotite, pentlandite, pyrite, chalcopyrite, magnetite and other spinels), though in the IDA deposits the volume of disseminated sulphides is far greater than that in the VPA deposits. Potentially all geophysical techniques have application in the direct detection of these deposits'gravity for the detection of the dense massive and matrix ore; magnetics for the detection of magnetite and pyrrhotite in the ores; electromagnetics for the detection of the massive and matrix ore; and induced polarization for the detection of disseminated and to some extent matrix and massive ore. In practice the application of geophysical techniques is limited to a varying extent by (1) the relatively small size of an economic accumulation of sulphides, particularly the VPA deposits, (2) the extreme depth of weathering and lack of outcrop on the Yilgarn Block and (3) the abundance of geological noise or anomalous responses caused by sources other than economic mineralization.

Jan 1, 1984

By M. W. Grabinsky, M. S. Diederichs, E. Hoek

Provided that they are used correctly, numerical models can be of considerable assistance to mining engineers in designing underground excavations. Guidance is given to the engineer or geologist who is not a specialist in numerical analysis but who is interested in using numerical modelling tools or in employing someone to analyse the stresses, displacements and failure in the rock surrounding underground excavations. A description of the theoretical background to a number of these numerical models and discussion of the advantages and disadvantages of each are followed by guidelines on the selection of appropriate models for each stage in the development of a mine, from exploration to the completion of mining

Jan 1, 1991

By S. K. Chaulya, R. S. Singh, B. B. Dhar

Two prominent local species, Dendrocalmus strictus (bamboo) and Saccharum spontaneum (kashi), and two exotic species, Cymbopogon citratus (lemon grass) and Vetiveria zizanoides (vetiver), were selected for growth trials on dumps at Mandaman, Chora, Mudidih, South Balanda and Ghugus. The climate at these sites is dry tropical and the surface soil layer a slightly acid to neutral sandy to clayey loam 10-11 cm thick, impoverished in major plant nutrients. After two years bamboo had grown the most, up to 325 cm in height, and contributed the greatest biomass, 638 g/m2 of plant. The local kashi species had a very good regenerative capacity, which was lacking in the lemon grass and vetiver. The grasses had very good soil-binding capacity and could also provide income if used as cash crops

Jun 21, 1905