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By J. Arzuúa, U. Castro-Filgueira, L. R. Alejano, F. Malan

"Pillar design for underground mining is typically done using empirical formulae or numerical modelling. Practical experience and recent literature, nevertheless, illustrate the shortcomings of these design approaches. Ongoing monitoring of pillars is therefore recommended to minimize the risk associated with these designs.In a mine where a large number of pillars are cut, different pillar strengths can be expected owing to variations in rock mass strength from area to area. This problem is compounded by the fact that in mining environments the pillars are not always cut according to the prescribed dimensions. Although the original design using either empirical methods or modelling may predict stable pillars, unstable pillars will be encountered in reality. Very conservative designs with large factors of safety may circumvent this problem, but this approach is uneconomical.A possible solution to localized stability problems may be to enhance the strength of a few unstable pillars. It may even be hypothesized that reinforcing a few critical pillars may prevent ‘pillar runs’ on a much larger scale. Rockbolting, strapping of pillars, and pillar shotcreting have occasionally been used in the past as possible solutions. It appears that these have not been successful in all cases and large collapses have occurred in spite of the pillar remedial work.The authors investigated the strapping of pillars by conducting laboratory tests on cabled rock specimens. The results were qualitatively compared to actual attempts of pillar reinforcement available in the literature, as well as additional observations in an old haematite roomand- pillar mine in Spain. Based on these results, the value of steel cabling and mesh wrapped around pillars to improve stability is demonstrated. Some cases where this approach will not be successful are also discussed."

Jan 1, 2017

Radioisotope x-ray and neutron techniques of analysis can be used for the determination of a wide range of elements in minerals. The most important applications of these techniques to the mineral industry are for onstream analysis of slurries and solids, and for geological assay.The radioisotope x-ray techniques are the more developed ones and two installations for on-stream analysis are in routine use in mineral processing plants in Australia. Neutron techniques are being developed, and should prove valuable for geological assay of large numbers of mineral samples, for borehole logging, and for specific on-stream analysis when the cost of the equipment is warranted.

Jan 1, 1970

John Langton, New York, N. Y. (communication to the Secretary*):—In Mr. Firmstone's discussion (Trans., xli., 912) the formula he gives for the periodical payment—his equation (2)—may be simplified in form. The expression given by Mr. Firmstone is : q=S(l+ r) 1-(1+r)-(1+r) r which is a simpler form to use in calculations. Where S= principal to bc extinguished. Q = periodical payment or charge for sinking-fund, r = rate of interest per period (i. e., interest on $1 per period). n = number of payments or periods. Kent's Mechanical Enyineer's Pocket Book, under the heading Annuities, equation No. 5, gives : " The annuity which $1 will purchase for any number of ytlars n is * Received Jiily 16, 1911.

Jan 1, 1912

By E. D. Regad, W. E. Wallace, P. S. Mike, C. A. Hill, V. Vallyathan, M. J. Keane

"Respirable-sized quartz, a well-established fibrogenic mineral dust, is compared with kaolin in erythrocyte hemolysis assays aher treatment with saline dispersion of dipalmitoyl phosphatidylcholine, a primary phospholipid component of pulmonary surfactant. Both dusts are rendered inactive after treatment, but the membranolytic activity is partly to fully restored aher treatment with phospholipase Ai. an enzyme normally associated with cellular plasma membranes and lysosomes. Phospholipid-coated dusts were incubated for periods of 2-72 h at a series of applied enzyme concentrations, and the adsorbed lipid species and hemolytic activity were quantitated at each time for both dusts. Surfactant was lost more readily from quartz than from kaolin, with consequent more rapid restoration of mineral surface hemolytic activity for quartz. Interactions of surfactant and mineral surface functional groups responsible for the mineral-specific rate differences, and implications for determining the mineral surface bioavailability of silica and silicate dusts, are discussed. INTRODUCTIONMineral particles depositing in the lung acinus will contact an aqueous coating containing surfactant molecules spread on the air-liquid interface and dispersed within this hypophase; the primary components of that surfactant are diacyl lecithin phospholipids (King and Clements, 1972; King, 1982). Adsorption of this surfactant can suppress the cytotoxicity of mineral dusts (Marks, 1957). Suppression of hemolytic activity, a measure of membranolytic potential and an indicator of bioavailability of the mineral surface, of respirable-sized quartz and kaolin clay dusts with the adsorption of dipalmitoyl glycerophosphorylcholine or dipalmitoyl lecithin (DPL) has been measured (Wallace et al., 1985). Such contact and adsorption of pulmonary surfactant in vivo may provide a first defense system of the lung against respired dusts."

Mar 1, 1992

By Michael Radnor

The purpose of the study was to 1) examine the social and economic impacts of surface mine blasting in relation to variations in conditions of terrain and geology, population density and type, levels of ground motion and air blast; 2) consider technical, legal and government policy issues; and 3) examine the potential, nature and extent of surface mine blasting impacts and its regulations upon both communities and surface mining companies. Phase One designed the empirical research and technical analyses of Phase Two, focused upon surface coal mining and quarrying in the Eastern U.S. Several broad conclusions are evident: 1) blasting is not the major issue for communities or surface mine companies; 2) while the number of instances of severe cracking or annoyance are relatively small, the impact can be severe for individuals immediately involved; 3) blasting/drilling cost curves tend to rise significantly at intervals below 1.0 particle velocity, in/sec, dependent upon the size of a permit area and the size of a mine; and 4) the legal, complaint, cost and density analyses do not suggest the need for a general lowering of present regulations.

Jan 1, 1981

By Fredrick M. Ryan

Present indications are that in about 2-3 years phosphor tags will be required in commercial explosives. A permissible 254 run ultraviolet lamp assembly has been developed to permit mine inspectors to detect such phosphor tags and therefore to establish if non-permissible explosives were used. This new lamp is powered by a Miner's cap battery without interference with the normal lighting requirements of the cap lamp battery. It is compact, light, and rugged with very high ultraviolet output.

Jan 1, 1977

The Annual General Meeting of the South African Institute of Mining and Metallurgy was held in Kelvin House on Wednesday, 25th August, 1976. Dr R. E. Robinson, (President) was in the chair, and declared the meeting open at 16h00. Obituaries The president: It is my sad duty to announce the death of the following members of the Institute : P. A. Creewell, Life Fellow; A. S. Davis, J. S. Hay, P. O. Large, N. McCaskell, and H. G. M. McKerrow, Life Members; C. L. Bererge, Fellow; T. Bulloch, G. Douglas, R. W. Forrester, and C. G. P. Sack, Members; P. R. Garcia, W. A. Naude, and J. P. Slager, Associates. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, I ask you to rise and observe a few moments' silence. Minutes The President: May we confirm the minutes of the General Meeting held on March 17th, 1976, as published in the June issue of the Journal? Agreed. Welcome The President: It is my pleasant duty to welcome a number of guests and distinguished visitors this evening. First, I would like to welcome Mr R. Plumbridge, the President of the Chamber of Mines, and Mrs Plumbridge. We have had very close co-operation with the Chamber of Mines, and it is particularly gratifying that Mr Plumbridge has had time to be with us this evening in spite of very heavy engagements. Ook 'n spesiale woord van verwelkomirg aar mrr. N. Orsmord, die Staatsmyringerieur, en mev. Orsmord. Ors wil hierdie geleertheid gebruik om mrr. Orsmord geluk to wens met sy aarstellirg as die Staatsmyrirgerieur en die hoop uitspreek dat dit baie jare van samewerkirg met hierdie Irstituut sal beteker. We also welcome guests who, in one way or another, have been able to attend most of our Annual General Meetings, the Honourable I. B. Dillon, the Minister of Mines of Rhodesia, and Mrs Dillon. Once again we welcome them most heartily to our Annual Meeting. I would also like to welcome the representatives of many of our sister institutions : the Honorary Treasurer of the AS & TS, Mr D. G. Maxwell; the President of the South African Institution of Mechanical Engineers, Mr A. R. Adams; the Vice-President of the South African Institute of Electrical Engineers, Mr K. A. H. Adams, and Mrs Adams; the President of the Institute of Certificated Mechanical and Electrical Engineer s, Mr Martin and Mrs Martin; a member of the Executive of the South African Institute of Civil Engineers, Professor G. Bright ; the President of the South African Chemical Institute, Mr Vic Shuller, and Mrs Shuller; the President of the Institute of Welding, Professor F. P. A. Robinson, and Mrs Robinson; the President of SACPE, Mr M. R. Gericke ; the President of the Institution of Metallurgists, South African Branch, Mr D. R. Allen; the President of FSPE, Dr P. J. D. Lloyd, and Mrs Lloyd ; Mr A. J. H. Pole of the Association of Mine Managers, and Mrs Pole; and Mr M. D. Hoskin of the South African Institute of Foundrymen. A special word of welcome to Mr G. C. Young of our Orange Free State Branch, and Mrs Young ; and to Mr E. J. Jackson of our Witbank/Middelburg Branch. We have great pleasure in welcoming Dr F. M. Naude, the Scientific Adviser to the Prime Minister, and Dr W. C. J. van Rensburg, Technical Director of the Minerals Bureau. The latter is a new organization, and we hope their attendance here this afternoon forecasts a long period of co-operation between the Minerals Bureau and this Institute. Ook wil ek hartlik hier verwelkom die Rektor van Die Randse Afrikaanse Universiteit, professor G. van N. Viljoen. Ors het baie noue samewerking met die Universiteit gekry, en ek wil ook bier verwelkom die twee verteenwoordigers van die Geologiese-afdeling en die Chemie-afdeling, naamlik, dr C. Roering en professor G. W. Holzapfel. Last, but by no means least, a word of welcome to a very old friend, Mr Eric Boden, the Manager of AS & TS. To all our guests, a very hearty welcome to this our Annual General Meeting. Membership The President: It is required by our Constitution that I announce the names of a number of candidates who have been elected to various grades of membership. The list is a very long one, and I suggest that we simply record that these names will be published in the Journal. Any one who wishes to comment on these members should do so in writing to our Secretary. Agreed. Fellows: G. Paterson, P. H. Adler, F. W. G. Schoning, J. P. de Villiers, F. I. de Waal, J. R. H. Shaw. Members: C. J. Slavin, P. J. Perkins, R. J. I. Butler, A. M. Hattingh, C. E. Alvey, J. A. Engelbrecht, P. L. Gouws, J. P. Martin, J. F. Taylor, K. A. G. Blendulf, A. R. Gibb, W. E. Smith. Associate Members: D. R. Broderick, D. F. Cilliers, D. N. Stuart, P. Kraus, B. G. Pinder. Associates: D. E. Gibbon, D. F. Jacobs, R. F. W. Swanepoel, R. D. H. Bebb, H. H. Vernall, R. D. Gibson, J. P. van Wyk. Graduates : A. N. Morris, D. J. Payne, G. S. Worthington, A. S. Dennison, A. R. Godfrey, N. Holloway, W. J. Rankin, G. S. Lyndon, R. J. van Proctor, J. J. Versluis, G. M. Miller. Students: B. J. Rabie, G. D. Webber, W. L. Blair, I. D. Mathews, K. McVey, S. W. Beer, R. W. J. Bentley,

Jan 10, 1976

By N. H. Darton

This report presents the results of an investigation begun by the Government in the summer of 1907, the investigation being started under the immediate supervision of Dr. J. A. Holmes and continued under him as director after it was transferred to the Bureau of Mines in 1910, the field studies being completed in the spring of 1912. The purpose of the investigation was to obtain information on the origin of the inflammable gases in coal and the conditions under which they occur. It was especially intended to ascertain whether there was any relation between the occurrence of gas and the structural or other geologic features of the coal beds. To this end many months were spent in mines and much time was devoted to the examination of mine maps, bore-hole records, and other data made available by the kindness of various coal companies. Two fields of work were selected-one in the northern anthracite basin of Pennsylvania, where the beds are considerably flexed, and the other in the southern part of the bituminous coal field of Illinois, where the beds lie nearly horizontal. In order to take advantage of results of previous investigations of the same general subject, an extended examination was made of reports of various investigators in Europe and America. A digest of the information obtained from these publications is included in the first part of this report, which constitutes an introduction to the discussion of the conditions governing the occurrence of inflammable gas in coal beds.

Jan 1, 1915

By M. J. Sapko

The Bureau conducted, through joint funding with the Colorado Mining Association, large scale oil shale rubble fire tests to investigate flotability characteristics and different methods of extinguishment. Ignition of large rubble piles was easily accomplished. Foam blankets could be used to control surface flames. The results of these large scale tests confirmed that water was effective in extinguishing deep seated oil shale fires but not particularly efficient. It took up to 1.7 times as much water to extinguish a fire as anticipated on the basis of a simple cooling model, assuming 100 pet utilization.

Jan 1, 1989

D. J. DEMOREST,* Washington, D. C. (written discussion ?).-This paper is a real contribution to technical science; it will make it' easier to think accurately about the inner workings of a blast furnace. I was rather surprised to read that the authors regarded as a new discovery the idea that a molten mixture of CaO, A1203, and Si02 is a molten solution of the compounds of these oxides rather than of the oxides in each other. Surely no. chemist with an active respect for the known facts of chemical affinity could believe that these oxides could be melted together without forming compounds, and that these compounds would then dissolve in one another. This work does, however, help to establish what it was supposed must be true. I think it is worth while, in the light of the work of the Geophysics Laboratory, this work of the Bureau of Mines, and that of previous investigators, to visualize what happens as a charge passes down through a blast furnace, thinking especially of the slag-forming materials. These are chiefly kaolin (Al203.2SiO2.2H2O), quartz, and limestone. These substances do not undergo much change until the limestone decomposes at about the middle of the furnace, whereupon the chemical affinities of CaO and SiO2 must begin to he active; especially if there is any amorphous Si02 present. This forms CaSiO3, and the SiO2, CaSi02 and Al2-032SiO2 then come together to form the binary and ternary eutectics so well located by the work of the Geophysics Laboratory. No matter how much lime has been charged into the furnace, the formation of this eutectic will start it about the same height in the furnace and the gangue will start to get pasty at the same height. If the charge is such that the

Jan 4, 1918

To improve communications between mine workings and surface locations during emergency situations and for administrative purposes. The Approach: Development of a device for interconnecting phone systems which permits two-way communication between a public telephone and a mine pagerphone by authorized personnel. How It Works: The system, developed by personnel at the Bureau's Pittsburgh (Pa.) Mining and Safety Research Center, makes connections between the public phone line and mine pagerphone line. As shown in Fig. 1., incoming calls are sensed by the ring detector (4) and the system "answers" the call electronically. To reach the pagerphone system, the caller inserts an audible tone of fixed frequency through the microphone of his telephone. This tone is produced by a miniature, pocket-carried tone generator and is detected by a tone recognition circuit (5). When this hap-pens, relay, switching, and logic circuitry (6) closes the connections between the two phone systems. Simultaneously, a page activator (9) places a DC paging voltage on the mine phone line.

Jan 1, 1974

By X. Shi

This paper presents design and implementation details of a fuzzy-behavior-based controller for an automated excavator. The robotic excavator is equipped with sensors, actuators and an embedded control system. The excavator controller uses neural-networks to interpret forces and torques gathered during the excavation process from bucket-mounted force sensors. Implementation details card experimental results using the fuzzy-behavior-based excavation controller are given for several excavation tasks. These excavation tasks demonstrate some of the complex skills that are essential for an autonomous mining-excavator controller.

Jan 1, 1997

Pressing-Drill Method - A Representative Method for Taking Analysis Samples from Recycled Materials

Sep 13, 2010

By John J. Reed

Since the beginnings of, the human struggle for survival and improvement, mining has been one of the basic endeavors of life. Until relatively recent times it was classed as an art. Now we are at work trying to, raise mining to the level of an engineering science where it belongs if we are to prosper. It should be self-evident that this goal can be attained only through industrial progress: based on education and research. It is true that our industry, left to itself, will develop a few new ideas and techniques through the years. However, we mining' engineers are relatively few in number compared to the other disciplines, and the rate of our improvement by such "accidental" discoveries is simply tooslow to keep pace with the rest of our technical civilization. It will be evident in the remarks that follow, that the rapid development of mining education, research, and the industry are extremely interdependent, and will be largely controlled by the amount of cooperation, support, and cross-fertilization that can be developed among all three.

Jan 1, 1961

By Paul D. Merica

This year of 1926 marks the 40th. anniversary of nickel mining in Canada. Although the first nickel mine of the Sudbury basin was discovered in 1883, it was not until 1886 that the Canadian Copper Company was organized and actually began to mine copper-nickel ore from the Lady McDonald, Stobie and Evans mines. The intervening years have witnessed some exceedingly interesting nickel history, particularly interesting and gratifying as well to Canadians. Forty years ago, at the inception of Canadian nickel mining, the world's consumption of that metal was about 1000 tons per annum and this was supplied largely from New Caledonia ores refined in France. This nickel was used principally for the production of nickel-silver, coinage alloys, and for nickel-plating. No processes were then known for refining the Sudbury ores nor for the separation of copper from nickel. Consequently, the pioneers in Canadian nickel mining faced the double problem of finding a method of treating their ores, and of finding a market for the nickel when and if they could extract it.

Jan 1, 1926

By George S. Rice

Those who for the first time see, at a mine, a great hole caused by subsidence; or, going underground, see an extensive fall of roof or hanging wall are apt to regard such an occurrence as an accident and not a normal condition of exhaustive mining. Moreover, the public is inclined to believe that a cave or subsidence of the surface is the result of carelcssness in mining or the rapacity of the mine operators in "robbing pillars," a tern too loosely used in descriptions of coal mining. This belief is fostered by the common-law requirement that an owner of the surface or of surface improvements is entitled to full support of the surface. Court decisions have upheld this law even when that owner has sold or leased the underlying mineral, unless a clause in the sale or lease contract exempts the mining company from paying the owner of the surface for damages that may result from mining. Another reason for this belief is the earlier practice (which is still extensively followed in this country) of leaving all coal pillars unmined, except as they have been thinned by so-called robbing; by not extracting the pillars, the surface may be supported by them for years, perhaps for generations. Inasmuch as the practice of leaving permanently in the mines from one-third to one-half of the mineral is wrong, with respect to conservation of a national resource, it behooves the mining engineers to assemble data and disseminate information on the subject, pointing out that subsidence must follow complete extraction, unless expensive methods of back-filling are employed, such as are used in Germany and France. These methods inevitably increase the cost of mining and the price of the mineral produced. It is popular to speak of "waste in mining" without a realization that much so-called wasting is unavoidable unless subsidence is accepted and provision made therefor where the surface is valuable, or else the only present known alternative of hydraulically placing sand or crushed stone filling in the excavations, at an increased cost of the mineral product to the consumer.

Jan 1, 1923

By George S. Rice

Those who for the first time see, at a mine, a great hole caused by subsidence; or, going underground, see an extensive fall of roof or hanging wall are apt to regard such an occurrence as an accident and not a normal condition of exhaustive mining. Moreover, the public is inclined to believe that a cave or subsidence of the surface is the result of carelcssness in mining or the rapacity of the mine operators in "robbing pillars," a tern too loosely used in descriptions of coal mining. This belief is fostered by the common-law requirement that an owner of the surface or of surface improvements is entitled to full support of the surface. Court decisions have upheld this law even when that owner has sold or leased the underlying mineral, unless a clause in the sale or lease contract exempts the mining company from paying the owner of the surface for damages that may result from mining. Another reason for this belief is the earlier practice (which is still extensively followed in this country) of leaving all coal pillars unmined, except as they have been thinned by so-called robbing; by not extracting the pillars, the surface may be supported by them for years, perhaps for generations. Inasmuch as the practice of leaving permanently in the mines from one-third to one-half of the mineral is wrong, with respect to conservation of a national resource, it behooves the mining engineers to assemble data and disseminate information on the subject, pointing out that subsidence must follow complete extraction, unless expensive methods of back-filling are employed, such as are used in Germany and France. These methods inevitably increase the cost of mining and the price of the mineral produced. It is popular to speak of "waste in mining" without a realization that much so-called wasting is unavoidable unless subsidence is accepted and provision made therefor where the surface is valuable, or else the only present known alternative of hydraulically placing sand or crushed stone filling in the excavations, at an increased cost of the mineral product to the consumer.

Jan 1, 1923

By A. P. I. Popoola, T. J. Olaniyi, A. A. Adeleke

"A laboratory froth flotation experiment was conducted on a low-grade carbonatite copper ore sample obtained from Phalaborwa in the Limpopo province of South Africa. The sample was a homogenous hydrocyclone overflow which serves as the feed to the flotation cells at Palabora Mining Company (PMC). The sample has an average copper assay of 0.59% with predominant copper-bearing minerals being chalcopyrite, bornite and cubanite. The carbonatite nature of the ore comes from the high content of calcium (28.85%) and magnesium (6.84%) minerals. Collectors used were sodium diethyl dithiocarbamate and potassium ethyl xanthate alongside Senfroth 38 supplied by Senmin. The results showed that at 200 g/t mixture of collectors (50:50), an optimum grade of 8.03% Cu in the rougher flotation concentrate was achieved at 74% recovery, while during the second flotation, 24.65% Cu was obtained at 74.4% recovery using a Senfroth 38 dosage of 6 L/t with 100 g/t mixed (50:50) collectors. The particle size and pH value of the pulp played a significant role in that the mixed collectors performed efficiently at pH above 8.3 and at room temperature while particle sizes greater than 53 µm were well concentrated when compared with those of less than 53 µm. INTRODUCTION The need for copper ore concentration research is on the rise as a result of the depletion of deposits and the advent of low-grade copper ores. Although most copper ore deposits have other valuable minerals that support their economic extraction, the increase in technological innovations as regards copper usage and applications has increased the demand for copper. Several factors influence concentration results in a froth flotation column, of which the reagent used is most influential."

Jan 1, 2015

This paper reviews recent positive developments in Europe on the regulation of gold mining. However, it also examines the problem that while gold projects may be bankable and technically and environmental defensible, the odds tend to be stacked against granting of an environmental permit. The historic background to this situation is examined and current developments and initiatives are critically analysed. Standards and benchmarks for the industry have been established across the community and these have a strong influence in European Union accession (and aspiring) states as well. While this is welcome in regard to improving environmental performance, it also represents a significant milestone with mining (and particularly gold mining) now æon the mapÆ as a legitimate enterprise, a situation that was patently not the case prior to 2003. At the project level, very frequently, the difficult biophysical problems are addressed and satisfactorily dealt with according to the new regulations, but still there are problems regards trust and acceptance that underpin a æsocial licenceÆ. What goes wrong and how can companies deal with the social/environmental issues that lead to entrenched views and concerns, irrespective of any amount of demonstration of good practice and corporate social responsibility? What is the role of the non-governmental organisation (NGO) and are they as accountable and responsible as they should be? The findings presented draw upon recent experience with the environmental permitting of projects in Spain, Greece, Romania, Bulgaria and Serbia on behalf of Australian, Canadian and British companies as well as international funding institutions.

Jan 1, 2007

Organization Place Date 1918 American Chemical Society Cleveland, O. Sept. 9-12 American Society of Sanitary En Engineers Chicago, Ill. Sept. 3-5 National Petroleum Association Atlantic City, N.J. -Sept. American Institute of Mining Engineers Colorado Sept. 2-7 National Association of Stationary Engineers.... Cincinnati, O. Sept. 9-13 Association Iron, Steel, Electrical, Engineers Baltimore, Md. Sept. 9-14 British Iron and Steel Institute, Autumn Meeting London, Eng. Sept. 12-13 National Exposition of Chemical Industries New York, N. Y. Sept. 23-28 American Electrochemical Society Princeton, N. J. Sept. 30- Oct. 2

Jan 9, 1918