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By R. J. Pine

Procedures are described for the application of risk analysis or probabilistic methods to mining geomechanics. The methods are widely applicable to existing mine design models. Detailed examples are given of plane slope failure and of pillar design based on displacement-discontinuity stress modelling and empirical strength assessment. The modelling techniques assessed are the Latin hypercube sampling method, incorporated in a spreadsheet environment, and the general point estimate method (GPEM), programmed in TurboBasic. An example GPEM program listing is included. Both methods are very convenient to use. Probabilistic acceptance criteria for slope stability after Priest and Brown are examined and alternatives are proposed where output distributions of factor of safety are approximately normal or lognormal and output distributions of safety margin are normal. The reliability index is included as a useful measure of variability with proposed acceptance criteria.

Jan 12, 1992

By Winmill T. F.

(Paper presented at the Institution of Mining Engineers' general meeting held in London on 8th June 1916.) The conclusions reached in this paper may be summarized briefly as follows: (1) The method of estimating moisture in coal by determining the loss in weight of a sample heated to 105°-110° Cent, in an air-bath for an hour is untrustworthy, the results so obtained being too low. (2) Dried coal has a very considerable power of absorbing moisture, and a sample, after being dried, must be protected instantly if it is to remain free from moisture. (3) A fairly accurate estimation may be made by heating the coal in a current of dry air at 105° to 110° Cent., and collecting the moisture evolved. (4) In cases in which it is proposed to use the dried coal for any further experiments, the drying must be done in the absence of oxygen, and this can be done simply and quickly by the vacuum method now described

Dec 1, 1916

By John Craw

This paper has formulated the methods, both medical and engineering, for the control of pneumokoniosis in the haematite-mining industry in West Cumberland, but this is only part of a general service to improve the lot of the worker in these mines, to make him a better and happier workman, and to permit him to enjoy his work and leisure in comfort and good health. This organization has now been functioning for more than ten years and the results are indeed heartening, but it is only as a result of constant vigilance from the mining and medical point of view that such a plan can operate efficiently. The human element and its full understanding is by no means the least of the problems.

Jan 1, 1947

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 C. C. Harris

The two best known graphical methods for presenting and comparing comminution data are obtained by linearising the Gates-Gaudin-Schuhmann and the Rosin-Rammler size distribution equations. It is shown that the Gates-Gaudin-Schuhmann equation can cause excessive congestion in the 50 per cent oversize range and that, overall, the Rosin-Rammler is a better procedure. Examples are given

Dec 1, 1971

The paper, presented at the North of England Institute of Mining and Mechanical Engineers' general meeting held in Newcastle-upon-Tyne, 8th April 1916, presents experimental work undertaken to observe the quenching effect of different substances, to find the most efficient of these substances, and to arrive at a possible explanation of their preventive action. The coal-dusts experimented with were such as passed through a 100-mesh sieve (10,000 holes to the square inch), and were obtained by grinding the coals. The quenching substances, used in as fine a state of division as possible, included gypsum, dried Chance mud, quicklime, magnesia, magnesia alba (levis), anhydrous sodium carbonate, sodium bicarbonate, soda-crystals, Glauber salts, ground shale and boiler-ashes

Dec 1, 1916

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 C. M. Lesher, R. R. Keays

"The komatnte-associated Fe-Ni-Cu sulphide mineralization at Kanihalda, Western Australia, is generally believed to be magmatic in origin, but a number of postmagmatic processes significantly modified the original distribution, structure, texture, mineralogy and chemistry of the ores. Two important types of mobilized magmatic sulphides are interpillow/interbreccia sulphides and hydrothermal vein-type sulphides. Interpillow and interbreccia sulphides occur interstitial to pillowed or volcaniclastic footwall metabasalts beneath or adjacent to the stratiform contact ore horizons. They are mineralogically and compositionally similar to massive ores (and are similarly depleted in PGE relative to the compositions of bulk samples of mined ores), but normally do not contain the distinctive chalco-phile ferrochromites characteristic of contact ores. They are interpreted as magmatic sulphides that have been mobilized from the overlying or adjacent massive sulphide layer during peak tectono-nietamorphism.Hydrothermal sulphide-quartz + albite veins also occur in the footwall metabasalt and contain unannealed deformation fabrics indicative of emplacement during retrograde metamorphism. The high Ni and Pd contents of these sulphides (7-13% Ni, up to 70 ppm Pd) indicate that the metals have been derived from the spatially associated komatiites and/or contact ores, consistent with the Pd depletion previously inferred for massive ores. Very low Ir contents and high Pd/Ir ratios of the vein-type sulphides confirm an aqueous transportation-deposition mechanism; hydrothermal transfer of PGE results in strong decoupling of Pd from Ir.There appears to be a complete continuum of sulphide mobilization at Kambalda ranging from whole-scale phy sical dislocation (fault offset ores) and selective mobilization (stringer sulphides) through nietamorphie replacement (interpillow/interbrec- cia sulphides) to jiydrothermal dissolution and redeposition (vein-type sulphides)."

Jan 1, 1984

By J. H. E. Jeffes, C. Diaz

The heat balance and chemical equilibria involved in the production of blister copper from a chalcopyrite concentrate in a single operation are examined. It appears that two stages—one oxidising and one reducing—will be required. The analysis indicates that on thermal grounds the process is possible with a dry, high-grade chalcopyrite concentrate, if oxygen enrichment to about 30 per cent is used, but that copper losses in the slag will be serious and will require a secondary recovery operation. More extensive data on the activities of copper oxide in slags are required to elucidate this point more effectively

Dec 1, 1971

By Stainier X.

The connexion between the Kent and the Continental coalfields on the one hand and the western British coalfields on the other has been for many years a controversial subject between geologists. These coalfields were once considered as detached portions of a former extensive sheet of Carboniferous deposits, but some geologists seem now to incline to the view that they were never connected. The writer hopes to show that the problem is one of the most difficult of geological investigations; that we are still far from a perfect solution; and that both of the extreme theories must be set aside. The physiography of NW Europe during the Carboniferous, with its various generations of earlier folds, is outlined and the features of the Lower and Upper Carboniferous anticlines and synclines discussed, followed by consideration of the denudation of the coalfields and local descriptions of the Malvernian range and Usk anticline, the Pennine chain, the Shropshire coalfield and the Kent coalfield. An attempt is made to trace the transverse Midland anticlines southwards and to deal with the intervening syncline: for example, if the dissymmetrical profile of the Pennine Chain holds good at its southern end then the syncline west of the chain must be deeper than the syncline east of it (the Kent syncline), and in this syncline the deepest part must be at its south-eastern corner, and therefore south of the diagonal ridge. T here is some actual evidence of the existence of Coal-Measures in this syncline, as the results of the Batsford and Burford borings prove. The hypothetical character of most of the conclusions will prove, beyond any doubt, how fa r geologists still are from a perfect settlement of this problem, and how much this settlement is dependent on the more or less advanced state of knowledge regarding all the geological features of these coalfields and of the surrounding country

Dec 1, 1916

By D. J. Buchanan

British Coal's mining research programme is directed towards the strategic objectives of reducing production costs, improving product quality and resolving health, safety and environmental issues. The strategy for R&D is described and selected parts of the programme are reviewed. Two major initiatives are directed towards reducing production costs: geotechnics and automation. Integrated exploration techniques are used to delineate geological structures as an aid to mine planning. Rockbolting is being rapidly introduced and the in situ stress field has been found to be of significant influence. Automation is the subject of a major programme. A strategy for coal quality has been devised. The health, safety and environmental programme concentrates on the traditional hazards together with surface environmental problems.

Jan 12, 1992

By R. R. Liebenberg, M. I. Brittan

The kinetics of the copper segregation process has been investigated. The experimental strategy used to isolate the rate-controlling reaction step is described. This step was found to be the chloridisation of the oxide copper minerals in the ore. The link between the rate of chloridisation and the overall rate of segregation is demonstrated experimentally. The influence on the kinetics of the various parameters in a TORCO system is examined and the implications are discussed

Dec 1, 1971

By Simons W.

The object of the paper is to describe the standards of quality that should be specified in ordering material ordinarily required for colliery use, and also the qualities most suitable for particular purposes. Tables are presented of British Standard tests for wrought iron grades A, B and C, Admiralty tests for iron in chain, the quality of material for wheels and axles, and the composition and mechanical properties of wrought iron, Armco (ingot) iron and drawbar-gear steel. (Paper presented at the North Staffordshire Institute of Mining and Mechanical Engineers' general meeting held in Stoke-on-Trent, March 27th 1916, Mr. John Gregory, President, in the chair)

Dec 1, 1916

By I S. Lowndes, K. Moloney

Diesel powered equipment is currently used extensively in mining and tunnelling operations around the world due to its mobility, flexibility and through selective application to enhance productivity. However, the increased use of diesel equipment has exacerbated the pollutant load (including heat, humidity, exhaust gases and particulates) placed upon the environmental systems of many underground operations. This expansion in the use of diesel equipment has prom pted researchers to evaluate m easure ment and control technology. This paper reviews the recent research conducted in various countries.

Jan 10, 1996

By M. Rahman, P. C. Kapur

The fixed-time locked-cycle grinding test is employed to simulate the industrial closed grinding circuit on the laboratory scale. A mathematical algorithm for 'cyclewise' computer simulation of the locked-cycle test has been derived and used to study an idealised laboratory-scale model of a closed ball-mill circuit. The agreement between simulated and experimental results is reasonably good, except when the grinding times are relatively long

Dec 1, 1971

By B. Sonmez, B. Aksanl, S. Ersaym, I. F. Erkal, S. L. Ergun

The comminution circuit at the plant has experienced severe problems arising from a feed containing much larger amounts of clay and having a higher moisture content than expected. Three solutions were proposed: replacement of the crushing circuit by tooth roll-type crushers; using washing drums; and introducing primary autogenous/semi-autogenous millling instead of crushing. Computer simulations studied the effects of the first two solutions on the circuit capacity. Laboratory and industrial scale ball mill batch grinding tests were carried out. The parameters of a kinetic model were determined. The ball mill circuit was sampled and operating model parameters were calculated. The ability of batch grinding parameters to represent the operating conditions was studied. Tests failed to find acceptable model parameters, but parameters from an industrial size batch mill were found to be suitable for simulation studies. The simulations indicated that a continuous feed of -12 mm provided by tooth roll crushers would maintain the desired capacity. Increasing the feed size to -25 mm would reduce the capacity by 8-15%. The use of washing drums could also solve the capacity problem, but small fluctuations in water flow rates might result in problems of excess water in the grinding circuit.

Jan 4, 1993

By Fergusson E.

An account is given of the history and operation of the Straits Tin market and the Penang price. The procedure by which the official ruling tin price is determined is presented and the way in which bids are treated is outlined: the price declared in Penang is the result of a joint operation by the two Malaysian smelters and is arrived at by finding the highest price at which the whole of the day's offerings for sale can be sold, thus reflecting the marriage of the offerings of the individual mine producers with the demand for Straits Tin from the consuming countries of the world. A system of accurate weighing, sampling and assaying of concentrates delivered to the smelters' premises enables the various ore-buying agencies of the two smelters to notify their central offices promptly of the estimated tin content of the concentrates their customers wish to price that day, so that by 11.00 a.m. both smelters will have exchanged with each other figures giving the total quantity of metal they have for inclusion in the day's market, at the same time exchanging particulars of the bids they have received. Miners are encouraged to sell regularly for cash and an evenness is thus achieved which avoids large daily fluctuations in overall quantity.

Dec 30, 1971

By C. H. J. Beaven, M. P. Jones

Since the various new techniques of automation and computing have enabled vast numbers of mineralogical observations of relatively small samples to be made cheaply and rapidly, the statistical assessment of these measurements has become of vital importance. Much of the theory and most of the procedures of sampling that are used in the mineral industry are based on Gaussian statistics, but modern measuring techniques show that many mineralogical parameters do not necessarily follow the Gaussian distribution function. Consequently, it has become necessary to examine the application of other, more suitable statistical methods in order to derive the maximum amount of useful information from the examination of mineralogical samples. Some of the errors that can be introduced by the use of incorrect distribution functions are discussed and the value of determining the function that is appropriate to the particular parameter that is being measured is shown. Examples are provided of non-Gaussian distribution functions in mineralogical materials that were encountered during prospecting and during mineral treatment operations: a Canadian uranium ore, a Thai tin ore, and gold ore tailings.

Dec 1, 1971

Thermodynamical data of importance in connection with copper smelting have been reviewed and a collection of the most reliable information is presented in Tables XXV-XXVIII and Figs. 67 and 6 8 (folding plate). The data given in these figures and tables consists of (i) graphs and equations showing the variations in the temperature range 0-2000°C. of the standard free energies of formation of most of the oxides and sulphides met with in copper smelting (Table XXV and Fig. 67); (ii) equations showing the temperature variation of the free energy of formation of iron silicates (Table XXVI); (iii) graphs showing the variation with temperature in the range 1000°-1600°C. of the standard free energies of the principal reactions occurring in the smelter (Fig. 6 8 ); (iv) the standard heats of formation at 1200°C. of the main iron and copper compounds and gases reacting in the smelter (Table XXVII); (v) the standard heats of reaction at 1200°C. of a few of the reactions for which the free energy relationships were given in Fig. 6 8 (Table XXVIII). The data presented are discussed in more detail.

Jan 1, 1953

Discussion following the presentation at the North of England Institute of Mining and Mechanical Engineers' general meeting held in Newcastle-upon-Tyne, 8th April 1916, included the author's introduction, written contributions by Bedson P.P., Gregory T.W.D. and Morgan J.D., oral contributions by Louis H., Greener T.Y. and Severs W., and the author's reply

Dec 1, 1916