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By W. L. Hollinshead

For more effective and cost-saving production in tunnels, the machinery used on construction sites in the future will be equipped with guidance systems combined with working-procedure management systems. This paper describes sensors for these systems and vari¬ous system configurations. A project is described that uses a computerized guidance system on an underground mining machine for guidance and profile control.

Jan 1, 2000

By D. Malhotra

Gold and silver ores are generally leached in weak cyanide solutions for recovery of precious metals. However, pretreatment of refractory ores requires flotation to concentrate the precious- metal minerals. Also, flotation is a common concentration technique for recovering precious metals as byproducts in sulfide-mineral flotation circuits. The present paper reviews current plant practice and future challenges for precious metal recovery.

Jan 1, 1999

By Charles L. Greening

MARTIN MARIETTA CEMENT at Martinsburg, West Virginia, has been and presently is engaged in coupling present open pit with old underground workings. Various drilling and blasting techniques have been introduced in an endeavor to achieve optimum results. This paper will relate to three roof shots at Martinsburg, one of which realized a controlled blast of 248,000 tons of material.

Jan 1, 1982

By Ian H. Clark

A series of numerical experiments were performed in order to elucidate the stress distribution, fracture strength and mineral liberation potential in single specimens of rock during crushing. Fracture strength was shown to reduce under eccentric loading conditions. Similarly, the presence of inclusions, both hard and soft, reduced the fracture strength. The predicted crack paths indicate that mineral liberation is unlikely to be preferential.

Jan 1, 1992

By Fuller T

This paper introduces the technology used in laser surveying systems, and the development of a reflectorless one-man total station. These systems are being used for applications such as blast pattern surveys, face profiling, muckpile surveys and the general survey of inaccessible areas. Black Diamond Solutions is continuing to assess new technology and develop integrated systems for applications in the mining industry.

Jan 1, 1995

By M. V. Kurlenya

The experience of application of geomechanical investigations for substantiation of extraction of undermined ore deposit in the north of Siberia is discussed. The finite element method was used for forecasting the state of massif during the development of mining works. The results of calculations were compared with the experimental data of observations in situ for evaluation of authenticity of numerical modelling.

Jan 1, 1990

By S. K. Kawatra, K. A. O, DeLa&apos

On-line sensors and process controls are important for efficient operation of coal preparation plants. The objective of this paper is to describe the current practice in on-line measurement of composition, density, moisture, level, flow and weight. This paper also discusses how on-line sensors can be implemented in process control, and how sensors which are currently being developed can be utilized.

Jan 1, 1988

Experience in evaluating grade control at operating mines has shown that a number of similar errors re-occur in diverse settings. These can be broadly classed as technical errors, and procedural or grade contra management errors. Examples of typical errors are presented a; generalised case studies. A brief explanation of why the recommender solution worked is also presented for each case.

Jan 1, 1993

By Rafael Abreu Fraga

Este trabalho tem como objetivo apresentar a nova linha de Laminação de Chapas Grossas da Usina de Ouro Branco da Gerdau, marcando a entrada da empresa na produção de chapas grossas de alto valor agregado no Brasil. A primeira fase do projeto consiste de um forno de reaquecimento de placas, um laminador de chapas grossas, sistema de resfriamento acelerado – Mulpic®, desempandeiras a quente e a frio e uma completa linha de acabamento constituída de linha de tesouras, oxi corte e máquina de ultra som. Neste projeto estão empregadas as mais modernas tecnologias para garantir a qualidade do produto: automação completa dos equipamentos com modelos matemáticos de controle do processo, sistema HAGC, Work Roll Bending e Work Roll Shiftting Smart Crown®. A nova linha tem capacidade de produção de 1,2 milhões de toneladas por ano na primeira fase, podendo alcançar 1,8 milhões de toneladas na segunda fase com espessura variando entre 6,0 a 150 mm e largura entre 900 a 3700 mm.

Aug 17, 2017

By Tiago Silva Costa

O processo que envolve soluções aquosas para remoção do metal de valor de uma grande massa de ganga, com um beneficiamento mínimo, é denominado Lixiviação. A especificidade do agente lixiviante empregado define a capacidade de tratar soluções com baixos teores do metal de interesse e o sucesso do processo. A lama da aciaria, recolhida no sistema de limpeza dos gases oriundos do convertedor LD, e a lama da eletrogalvanização, gerada após a neutralização da solução de zinco contaminada com ferro, são resíduos sólidos gerados nas usinas siderúrgicas com potencial de serem reutilizados ou reciclados. A fim de se remover o óxido de zinco presente nas lamas, amostras foram coletadas e preparadas para sofrerem o processo de lixiviação em escala laboratorial usando soluções de hidróxido de sódio (NaOH) e ácido sulfúrico (H2SO4). Os resultados obtidos nas análises mostraram que é possível remover óxido de zinco através da lixiviação das lamas.

Aug 16, 2017

By E. J. Schmitz

This section was obtained last year during an examination of the iron-ore resources of the Rich Patch Mountain region and along Craig's creek valley. The geological members below the Oriskany and Lower Helderberg are exposed along the gap in a beautiful arch, while the higher formations appear in a more or less disturbed state on both sides of this arch, and are partly covered by dèbris. I have thought it of interest to the Institute to reproduce the drawing of this section at the gap which I made in my note-book at the time of my examination; those parts of the section, which lie at both sides of the arch, are only approximated. I give also a number of notes and measurements, referring to the Clinton formation and especially to the characteristics of the fossiliferous ore-seam opened in the various tunnels along the arch (see section). I. In Tunnel C: For the first 110 to 120 feet to second shute, we find the ore only here and there in small deposits, and interchanging with, or changing into, either a very siliceous limestone or a sandstone. About 10 feet beyond shute we have : Sandstone roof. Clay-slate, 211/2 inches Brown lean ore, 1 inch. Sandy clay, 3 to 31/4 inches. 1. Dark .brown ore, 3 inches. 2. Fossil-ore, changing into sandstone or very siliceous limestone, 2 inches. 3. Brown lean ore, 6 inches. Clay and slate below, 1 foot. 194 feet from entrance : Sandstone roof. Clay-slate, 4 inches. Clay 15 inches. Fossil-ore, 63 to 7 inches. Clay and ore, If inches. Lean brown ore, 2 inchea. Clay to bottom, 2 feet.

Jan 1, 1896

By James Douglas

No one mill attribute it to the partiality of friendship if I claim for Thomas Sterry Hunt the right to a place among that little band of men whom nature has endowed with what seems an almost magical power of insight into her mysteries. But those of us who knew him well, while me never ceased to wonder at the breadth of his genius, the fertility of his imagination, and the wonderful capacity of his memory, learned that these native powers would have availed little to win him his rank in science, had they not been stimulated by ceaseless mental activity, indomitable perseverance, and unflagging industry. Thomas Sterry Hunt was born in Norwich, Connecticut, on September 5, 1826. He came on his mother's side from that good old stock which gave to Puritan England the gentle mystic Peter Sterry and that uncompromising preacher Thomas Sterry, who wrote the notable tract, " The Rot among the Bishops " in 1667, and that gave to New England Consider and John Sterry, the mathematicians. While lie was a child the family moved to Poughkeepsie on the Hudson. There the father died when Thomas, the oldest son, was twelve. The mother and her family of six young children returned to the old home in Connecticut. For a short time Thomas attended the public school; but it was for a short time only, as he, thus early, was required to share the burden of the family support and to seek employment. This he found first in a printing-office, then with an apothecary, afterwards in a book-store. The surroundings may have been congenial, but the occupation probably was not; for he re-

Jan 1, 1893

By Carter D

The Chairman of this afternoon's session is Dick Carter. This afternoon is the culmination of this conference. We've looked in the first session at regulation; in the second session at valuation techniques and this session we look at valuation in practice. Dick's involvement in the mineral industry has been wide ranging and distinguished. Dick has worked with BHP since 1960, when he joined BHP Steel as a commercial trainee. Dick holds a B.Comm. from the Newcastle University College of the University of New South Wales and was educated at the Australian Administrative Staff College and Harvard Business School Advanced Management Programme. During the past decade, he has headed the minerals group's Aluminium Divison, Resource Planning and Development, Non-Ferrous Metals and Business Development Organisations. Dick currently serves as Executive Director of BHP Gold Mines Limited and Managing Director of Ok Tedi Mining Limited. His experience covers Australian Manganese Company, Mineral Deposits Limited, Northern Rivers Rutile, Tasmanian Electrometallurgical Company Limited, Mount Newman Joint Venture, Worsley Aluminium and Carnilya Hill Joint Venture Operating Committee. His industry associations include the Executive Board of the Gold Producers Association, the Federal Executive of the Australian Goldmining Industry Council as well as the World Gold Council. Ladies and gentlemen, Dick Carter.

Jan 1, 1989

The Annual General Meeting of the South African Institute of Mining and Metallurgy was held in Kelvin House, Johannesburg, on Wednesday, 27th August, 1980. Mr D. A. Viljoen (President) was in the chair and declared the meeting open at 4.05 p.m. Obituaries President: It is my sad duty to announce the death of the following members of the Institute: T. C. A. Meyer (Past President, 1941 to 1942); E. G. Harding, T. A. Stannard, C. T. Hardy, W. C. Jackson, J. S. Sinton, G. H. Duggan, H. H. A. Muller (Life Fellows); W. M. Frames, K. Gebhard, W. M. Walker, S. L. S. Swart, N. W. Stansmore, H. E. Allen, B. W. F. Towne, R. A. Wilson, D. Waterman (Fellows), R. M. Peterson (Life Member); D. L. Gibbs (Member); B. M. Williams (Asso¬ciate Member); D. B. T. Cresswell, P. G. Guernier (Associates). As a mark of respect to the memory of the deceased, and in sympathy with the bereaved, please rise and observe a few moments of silence. Notules President: Kan ons die notules van die Algemene Jaar¬vergadering, wat op 22 Augustus 1979 gehou was en in die September uitgawe van ons Joernaal gepubliseer is, bevestig? Bevestig.

Jan 1, 1980

By E J. Gardiner, C M. Hogan

Acidic drainage has long been recognised as the largest environmental liability facing the mining industry, and to a lesser extent, the public, through abandoned mines. The Canadian Mine Environment Neutral Drainage (MEND) initiative was the first international multi-stakeholder program to develop scientifically based technologies to reduce the effect of acidic drainage. The original MEND Program extended over a nine-year time frame ending in 1997, with technology transfer activities continuing to the end of year 2000 under the MEND 2000 program. Both programs have contributed enormously to the understanding of acidic drainage and how to prevent it. MEND3, launched in 2001, intends to further this effort with a strong, research-driven program. The successes of the MEND initiative have come through the collaborative efforts of the partners, the sharing of experiences, the thorough evaluation of technologies and their incremental improvements. As a result, the knowledge base on acidic drainage has grown considerably. An international model of alliance between the various worldwide initiative involved in acidic drainage is being formalised at this conference. This global alliance will enhance technology transfer capabilities and will lead to improved environmental performance for the industry. It is through collaboration that we have achieved the most progress in environmental performance, and this formal relationship will further expand these benefits.

Jan 1, 2003

President Robert Wilson opened the meeting at 9:00 a.m. He introduced William A. Bear, General Manager Bear Coal Company, Inc., Somerset, Colorado, who presided over the session. George Nugent, Peter Kiewit Sons' Company, Sheridan, Wyoming, presented a most interesting film "Montana Mine Reclamation." His biography follows: George Nugent first entered the coal business in 1943 when he developed Peter Kiewit Sons' Co.'s first coal mine-Big Horn Coal Company at Sheridan, Wyoming. Since that time he managed an expansion program for P.K.S. in mining that resulted in the development of two other producing mines - Rosebud Coal Sales Company at Hanna, Wyoming and Decker Coal Company at Decker, Montana, in which Pacific Power and Light is a partner. Applications are now pending for a third mine. Black Butte, a joint venture of P.K.S. and Rocky Mountain Energy Company, near Point of Rocks, Wyoming. Nugent is a Past President of the Wyoming Chapter, Association of General Con- tractors, Wyoming Mining Association and Rocky Mountain Coal Mining Institute. He was President of Big Horn Coal Company and Rosebud Coal Sales Company as well as Manager of the Mining Division of Peter Kiewit Sons' Co. and Decker Coal Company when he retired Jan. 1, 1975.

Jan 1, 1976

US Tin Mission To Study Costs in Far East A move to obtain adequate supplies of tin at prices the United States is willing to pay was initiated when the interagency tin mission left for the Far East. The Mission, which includes representatives of the Reconstruction Finance Corporation, State Department, Defense Minerals Procurement Agency and the Bureau of Mines will go to Indonesia and Malaya. The primary purpose of the mission, according to officials, will be to study tin production costs, not to negotiate for the purchase of tin. The mission will be prepared to enter into negotiations, if the Far Eastern producers are amenable. The United States withdrew as a large-scale buyer of tin some months ago in protest against what it considered exorbitant prices being charged in the Singapore market. Subsequent attempts to negotiate for a steady tin supply at what this country considers reasonable prices have been unavailing. The U. S. is prepared to enter into a two or three year contract with the price of tin somewhere between $1.00 to $1.12 per lb. The decision to abstain from the market has not yet put a squeeze on U. S. supplies. Substantial quantities of tin still are coming in from Malaya under an old contract.

Jan 12, 1951

By P. A. Beck, A. H. Lutts

IN the classical picture of recrystallization the growth of strain-free grains at the expense of a strained and work hardened matrix is responsible for the softening of cold worked metals on annealing. It has been commonly assumed that the release of the stored energy of cold work, softening, and re-orientation take place simultaneously, as the high angle boundaries of the new recrystallized grains sweep over the cold worked matrix. However, recent evidence indicates',' that, at least in some cases, considerable or even complete soften- ing may take place essentially without reorientation (i.e., without the migration of ordinary high angle grain boundaries, or "recrystallization'') and the release of most of the stored energy of cold work may precede softening. These cases suggest that the property changes, taking place during the annealing of cold worked metals, may be associated with various distinct processes. The study of such situations is of considerable interest, since quantitative data are still scarce. In the present work, isothermal softening curves were determined for a heavily rolled aluminum single crystal, under such conditions that no "recrystallization" occurred until after complete softening. The hardness data were correlated with X-ray diffraction pinhole patterns in order to detect any reorientation that may occur and with measure-

Jan 1, 1955

By David Ellis

The next generation of Reusable Launch Vehicle (RLV) will utilize regeneratively cooled combustion chamber liners in the engines. The current design calls for using a new Cu-8 at. % Cr-4 at. % Nb (Cu-8 Cr-4 Nb) alloy for the liners. Work is ongoing to characterize the thermophysical and mechanical properties of the alloy from - 253 to 800°C, the temperature range to which the alloy will be subjected during service. The alloy has been commercially produced in quantity for NASA. The powder size has been characterized and the microstructure examined. The powder was extruded into bar using a commercial extrusion press. In addition, samples have been hot isostatically pressed (HIPed) at NASA Glenn Research Center. Both processing methods produced fully consolidated material. Transmission electron microscopy (TEM) revealed highly faulted Cr2Nb and some elemental precipitates. Cryogenic tensile testing showed the extruded specimens had significantly higher strengths than NARloy-Z (Cu-3 wt % Ag-0.5 wt % Zr) even after being subjected to a simulated braze cycle. The Young's moduli (Cu-8 Cr-4 Nb) were lower than NARloy-Z. The lower moduli is highly beneficial for reducing thermally induced stresses in rocket engine combustion chamber liners and similar applications.

Jan 1, 1999

By John C. Smock

The ten years, 1879 to 1888, inclusive, have been notable in the history of iron-making for the great rise during the latter part of 1879 and the earlier half of 1880; for the maximum of production in 1882 ; for the gradual decline and the reduced product through 1883,1884 and nearly to the end of 1885; then, for the recovery through- 1886 and 1887; and the extraordinary outputs of our iron furnaces during the last three years. The price of pig-iron might be taken as an index to the condition of the iron-mining industry, and if represented graphically, they would shorn approximately parallel curves. The mining industry cannot always respond quickly to a rise in price and an increased demand for ore; nor can its production drop simultaneously with sudden falls in price of iron and of ore. Hence, the irregularities of the one are not reflected in the other. The statistics of the iron mines collected by the United States census, for the year ending June 30, 1880, exhibit admirably their condition at that time. The reports received from mine owners and managers, of the production for the year 1888, furnish the basis for a comparison and supply data for some notes on the changes in the iron-mining industry in New York which have taken place in this period of time. The iron-ores of New York may be grouped in the following districts: I. The Highlands of the Hudson (magnetites). II. The Lake Champlain and Adirondack Region (magnetites). III. St. Lawrence and Jefferson Counties (red hematites). IV. Clinton and Wayne Counties (fossil-ores of the Clinton Group). V. Dutchess and Colnmbia Counties (limonites). VI. The Hudson River (carbonates). VII. Staten Island (limonites). The ores of the first and second districts, as enumerated, are almost exclusively magnetites; those of the third and fourth are hematites;

Jan 1, 1889