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PRESIDENT CHARLES F. RAND,1 NEW YORK, N. Y. PAST PRESIDENTS CHARLES KIRCHHOFF,1 NEW YORK, N. Y. JAMES F. KEMP,2 NEW YORK, N. Y. FIRST VICE-PRESIDENT BENJAMIN B. THAYER,1 NEW YORK, N. Y. TREASURER GEORGE C. STONE,1 NEW YORK, N. Y. SECRETARY EMERITUS ROSSITER W. RAYMOND NEW YORK, N.Y. SECRETARY BRADLEY STOUGHTON NEW YORK, N. Y.

Jan 1, 1914

By W. I. Nelson

This paper which describes the milling practice of the Engels Copper Mining Co., is one of a series on milling methods being prepared for and published by the United States Bureau of Mines. ACKNOWLEDGMENTS Acknowledgment is made of the assistance rendered by J. Casagrande, mill foreman of the Engels concentrator, in collecting much of the data presented in this paper.

Jan 1, 1932

By X. W. Pan

It has been found that the MnO content of a slag decreases sharply when direct current is applied to a 1T1£tal-Slagsystem consisting of liquid Mn-Si-Ccsat metals and MnO-SiO2-CaO-AI203 slag in graphite crucibles. This paper reports a preliminary investigation into the electrochemical effects of direct current on the metal-slag system, the silicon content of the metals, and the MnO content of the slag. The results show that, when a direct current of 7 A is maintained, the MnO content of a metal containing 10 to 11 per cent silicon by weight is reduced rapidly from 26,5 to 17,2 per cent by weight. This reduction seems to proceed further when the process is continued. When the direct current and the voltage are kept constant at TA and 4 V respectively, the MnO content of a metal containing 1 to 2 per cent silicon by weight is reduced to 1 from 25 per cent by weight, which results in a manganese yield of 96 per cent.

Jan 1, 1995

By Albert W. Deurbrouck

The performance of four sand cones was evaluated by the Bureau of Mines in three preparation plants that utilized cones in various flow schemes. The cone at plant A was a simple two-product one that provided clean coal and refuse. Plant B had two cones; one cone made a primary separation and the other a secondary separation. The primary cone separated salable coal from heavy rejects. The secondary cone separated a low-ash metallurgical coal and an intermediate-ash product suitable for plant fuel or steam markets. In plant C the sand cone was equipped with a middlings draw Which continually removed an intermediate specific-gravity product below the surface of the cone. The three primary separations of raw coal effected between floats and sinks were excellent. The recovery efficiencies for the plus 1/4-inch material ranged from 99.8 to 97.6 percent, the error areas ranged from 19 to 23 square centimeters, and the probable errors in specific gravity ranged from 0.033 to 0.024. The performance data of the two secondary separations varied from excellent in plant B, where the separation was on a par with the primary separations, to somewhat inferior in plant C, where the secondary separation was effected at the middlings draw.

Jan 1, 1965

By G. W. Jones

The Bureau of Mines has advocated the use of stenches as warning agents in metal mines and in gas-distribution systems since 1920 A considerable amount of research has been conducted on ethyl mercaptan and other compounds to determine their effectiveness when used for this purpose.4/5/6/7/8/9/10/11/12/13/ Miners are warned of danger by a stench injected, in measured quantity, into a compressed-air line through which it is rapidly carried to the working faces, where it escapes from the compressed-air equipment and imparts a characteristic odor to the air. This method is not applicable to mines where only a limited number of com-pressed-air lines are used, as for example, many coal mines; the ventilation currents available in these mines may be too slow for warning purposes.14/

Jan 1, 1954

By B. K. Shibler

During the investigation of the occurrence of manganese deposits in the Western United States, examining engineers of the Bureau of Mines collected 2-ton samples from five manganese properties near Golconda, Nev. Extensive laboratory tests were made to determine the amenability of these ores to standard ore-dressing methods of concentration. The Tom Major property, one of those sampled, is situated 12-1/2 miles south of Golconda, Humboldt County, Nev. The deposit is described as a bed about 5 feet thick in a thinly bedded shale and dolomite formation. The sample tested was obtained from the manganese bed, but the examining engineer reported: "The mining of an appreciable tonnage at reasonable cost would perhaps cut in half the grade represented by the sample."

Jan 1, 1951

By Flávia Guimarães Rocha Godinho Campos Vargas

Amostragem pode ser definida como a sequência de operações que visam retirar do todo (lote) uma parcela (amostra) que conserve as propriedades de interesse do lote. O menor erro possível em um protocolo de amostragem é chamado de erro fundamental de amostragem (FSE), o qual está associado à heterogeneidade constitucional do minério e pode ser estimado através de testes de heterogeneidade. A realização do teste de heterogeneidade com minério fonte de zinco, proveniente da mina de Vazante, permitiu concluir que a heterogeneidade da willemita é menor que a heterogeneidade de minérios de ouro e maior que a de minérios fonte de alumínio, por exemplo. Além disso, os resultados do teste de heterogeneidade permitiram a otimização do protocolo de preparação de amostras do laboratório físico, reduzindo o erro total de 13,4% para 6,0% sem investimentos em infraestrutura de laboratório.

Aug 17, 2017

By Braxton P. Erbe, Douglas C. Brunot

A variety of systems and techniques exist to support deep excavations where sloping is not feasible. This paper will explore an example project involving the use of pre-engineered hydraulic bracing systems to support sheet pile walls. Challenges on site that drove the final design include a high water table, irregular excavation geometry, and underground obstructions. The hydraulic system, connected by pins and not requiring welds, allowed for quick deployment and the modularity to change as required due to unforeseen site conditions.

PRESIDENT BENJAMIN B. THAYER,1 NEW YORK, N. Y. PAST PRESIDENTS JAMES F. KEMP,1 NEW YORK, N. Y. CHARLES F. RAND,2 NEW YORK, N. Y. FIRST VICE-PRESIDENT SIDNEY J. JENNINGS,1 NEW YORK, N. Y. TREASURER GEORGE C. STONE1 NEW YORK, N. Y. SECRETARY EMERITUS ROSSITER W. RAYMOND, NEW YORK, N. Y. SECRETARY BRADLEY STOUGHTON NEW YORK, N. Y

Jan 3, 1914

By Sally A. Shoop

Thirty-seven blasts have been monitored using either three or four seismographs, at four coal strip mines and at a limestone quarry. Statistical analysis of the data shows that square-root, cube-root, and site-specific scaling methods predict peak particle velocities with about the same (low) degree of reliability. Some mines have peak particle velocities that are significantly lower or higher than the U.S. Bureau of Mines averages (Siskind et al., 1980). This suggests that the option provided by the proposed regulations (Office of Surface Mining, 1983), to adjust blast designs based on site-specific measurements could be highly beneficial both to operators and to the public. The frequency spectra reveal that the predominant frequencies were generally less than 50 Hz but several blasts had a significant amount of energy up to 125 Hz. In some cases the vibration energy was concentrated at frequencies corresponding to the delay intervals.

Jan 1, 1983

By Nordau R. Goodman

"IntroductionTHE HISTORY of Nova Scotia's gypsum industry goes back about two hundred years. The extensive deposits found in the Windsor formation, which is Lower Carboniferous, were the first discovered in North America and were known to the earliest .settlers. There has been a steady increase in production from these beds, except for minor setbacks in years of wars and depressions, but at the same time there has been a decrease in the number of operating quarries. This decrease reflects the change from the days of horse-and-cart recovery to the modern, large-scale, highly mechanized operations. In the beginning, almost any outcrop could •supply the tonnage requirements and the most •convenient were selected, but the millions of tons needed to meet present-day needs are not easily found.Despite the size and importance of the Nova Scotian deposits there has been little detailed geological work. Sir Charles Lyell, in 1843 ( 10), established that the beds are Lower Carboniferous and this was confirmed by Sir William Dawson (3) a .few years later. Both Lyell and Dawson agreed the calcium sulphate beds were an original part of a bedded series .but did not consider they resulted from a concentration of sea water. Lyell reached the conclusion that the gypsum was related to volcanic action in the form of heated vapours or hot springs. Dawson believed it was formed by the action •of sulphuric acid on calcium carbonate. The acid, derived from the oxidation •of iron pyrites which was abundant in the older formations, was carried by rivers into basins which were rich in shells."

Jan 1, 1954

By Oscar Marreros Daza

Dada la complejidad de las rocas y cuerpos mineralizados en el Tajo Mc Cune de Cerro de Pasco, es más difícil calcular los parámetros óptimos de perforación y voladura por métodos manuales. En este sentido, el presente texto describe un programa en Basic para la computadora IBM Pc, donde se puede hacer un análisis de estándares de voladura y costos para cualquier diámetro de explosivo, tipo de roca, explosivo y altura de banco. Asimismo, se considera el método de cálculo de los estándares de perforación y voladura perteneciente a Richard L. Ash y se realiza el análisis de voladura con ANFO para los diferentes tipos de roca dado su bajo costo y rendimiento

Nov 24, 1986

By Flaviani Marculano Marchesi, Silas Gambarine Soares, Elton Volkers do Espírito Santo, Felipe Fardin Grillo, Heitor Cristo Clem de Oliveira

O objetivo deste trabalho é utilizar a termodinâmica computacional para estudar as propriedades de escórias iniciais dessulfurantes utilizando misturas com diferentes fluxantes: fluorita, sodalita, borra de alumínio, B2O3 e ilmenita. A princípio, as misturas foram definidas e em seguida foram realizadas simulações para o aquecimento dessas misturas a 1350 ºC por meio do software FactSage 7.2. Assim, foi calculado o fator de dessulfuração (FDeS) para cada mistura com base nas condições de equilíbrio. As misturas contendo 5 e 10% de fluorita e 5% de sodalita foram as que apresentaram maior FDeS. Em contrapartida, as misturas com 10,15 e 20% de B2O3 tiveram os piores resultados nessa análise. Misturas da literatura também foram simuladas a fim de se obter o FDeS e relacioná-lo com a eficiência.

Oct 1, 2019

PRESIDENT. CHARLES F. RAND,1 NEW YORK, N. Y. PAST PRESIDENTS. CHARLES KIRCHHOFF,1 NEW. YORK, N. Y. JAMES F. KEMP,2 NEW YORK, N. Y. FIRST VICE-PRESIDENT. BENJAMIN B. THAYER,1 NEW YORK, N. Y. TREASURER. GEORGE C. STONE,' NEW YORK, N. Y. SECRETARY EMERITUS. ROSSITER W. RAYMOND NEW YORK, N. Y. SECRETARY. BRADLEY STOUGHTON NEW YORK, N. Y.

Jan 7, 1913

By P Duplancic and C R Lilley, R Hudson, D Beck

For deep block and panel caving mines, undercut or extraction level instability can have as much impact on overall recovery as underbreak or the premature ingress of waste. If the area of the mine affected by excessive convergence is small, recovery is usually possible. However, there are several examples of entire blocks that were abandoned prematurely due to footprint collapse. Clearly, such global instability has a major impact on recovery and must be avoided – this is one of the essential tasks for the design team.The design problem is complex. The planning engineer must ensure that the footprint has sufficient capacity to withstand the maturing loads in the cave, accounting for the effects of stress path, geological structures and the rock mass conditions. These are often uncertain and only sometimes quantified.The demand on the footprint will also be influenced by decisions and actions taken during production, especially related to draw, which can worsen a developing problem. Perhaps most importantly, the design decisions that favour stability and lead to lower deformation also negatively impact on idealised cave flow. Many engineers aim to minimise the size of extraction level pillars, to improve theoretical future resource recovery but in fact this can reduce recovery if widespread deformation ensues due to the undersized pillars.In 2014, PT Freeport Indonesia undertook detailed numerical analysis to quantify the effects of variability in rock mass conditions and geological structure on overall footprint performance. The analysis accounted for a range of stress paths and maturing cave loading scenarios sourced from a calibrated whole-of-cave deformation-flow model. The intent was to replicate some of the diversity and distribution of pillar deformation outcomes that may be seen in practice at Freeport.The discontinuum finite element analysis was able to replicate damage localisation around persistent structures, a realistic distribution of drive deformation and show how small areas of instability can evolve into major problems if poorly managed. The limits of pillar size and ground support as solutions to a number of different instability problems was also investigated, showing that pillar size alone was not a sufficient remedy for all adverse circumstances.In this paper, we describe the workflow for numerical analysis of footprint deformation. We discuss the compromises and considerations for balancing the sometimes competing needs for efficient extraction levels pillars, ground support and prudent draw strategy.CITATION:Beck, D, Hudson, R, Wilson, A D, Duplancic, P and Lilley, C R, 2016. An investigation of factors affecting the long-term reliability of extraction level pillars in deep block and panel caves, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 295–304 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Scott Turner

AS IN OTHER lines of engineering, progress in mining was influenced during 1931 by the world-wide economic depression. Low-metal prices ? resulted in active efforts to reduce production costs of base-metal mines. Probably the chief factors in reducing costs were the greater efficiency of labor, due to better relations between management and workmen, to the scarcity of jobs, reduced wages in most base-metal mines, and to lower overhead expenses secured by drastic economies. The use of mechanical equipment continued to increase, due to more efficient designs and a better practical understanding of the applicability of such equipment to requirements. With one exception, there were no startling innovations in stoping methods, but there was notable progress in the better adaptation of mining methods. In the United States, no large new base-metal or silver mines came into production during the year. At a number of mines, output was curtailed, and operations were discontinued at several important producers. On the other hand world-wide interest in gold was stimulated, as evidenced by increased output from producing mines, the reopening of some old properties, and intensive prospecting for new deposits. Mining methods at several gold mines in the United States and Canada were modified or changed to obtain a higher extraction of ore or to meet the need for additional support of the mine workings at depth. Permanent record of improvements in mining practices has been made during the year by the Federal Government; the industry thus has available for its use more detailed information than ever before. This work was done through cooperation of the mining companies and their representatives with the United States Bureau of Mines, whereby many papers descriptive of practices and costs at individual mines have been published. The Bureau's program of describing methods and costs at the more important mines (those producing in excess of $100,000 annually) is nearly completed, but papers will be issued concerning such additional mines as may possess particular interest because of novel methods, exceptional conditions or operating results, and others to supplement reports already issued. In this way, an interesting record of the results of changing conditions, or innovations in methods, will be made available.

Jan 1, 1932

By Pedro Jorge Walburga Keglevich de Buzin

A produção siderúrgica em usinas semi-integradas gera vários tipos de resíduos dentre os quais as carepas. No presente trabalho estuda-se o comportamento físicoquímico em altas temperaturas de briquetes autorredutores elaborados com carepa e finos de carvão vegetal produzidos no Rio Grande do Sul, objetivando sua introdução no processo produtivo de aciaria elétrica. Ensaios realizados em laboratório com briquetes industriais confeccionados com estes resíduos demonstraram a potencialidade de utilização destes briquetes autorredutores em processos siderúrgicos via forno elétrico a arco (FEA).

Aug 16, 2017

By Felipe E. Olivares S

"El presente texto revisa el origen y distribución de los metales raros como parte de un proyecto de recuperación de subproductos de valor comercial en la fundición de La Oroya. Para ello se reeexaminan ocho minerales raros (bismuto, selenio, teluro, cadmio, talio, indio, bismuto, indio de alta pureza), cuya composición de elementos raros se registra en la concentración de algunos productos o residuos. Estos minerales son del grupo del cobre Chalcópirita, Enargita, Tetrahedrita, Bornita y Chalcosita; del plomo: la Galena, Jamesonita y Gratonita, y la Esfalerita que proporciona el zinc. Los concentrados y minerales que entran al proceso de fundición se reparten en tres circuitos principales: cobre, plomo y zinc. Los circuitos de los primeros están ligados entre sí por el sistema de Cottrelles y los procedimientos de las mismas fundiciones, mientras que el último actúa de forma independiente. Por último, es competencia del Departamento de Investigaciones, la recuperación de dichos subproductos a través del proceso de concentración y fundición, como de a búsqueda nuevos métodos en el campo minero y metalúrgico. "

Jul 20, 1956

By B. K. Belle

The beginning of 21st century has heralded the global strategic importance, as evidenced by increase in energy prices and energy generation-emission-utilization dilemmas. In January 2008, the South African energy supplier, ESKOM had tabled the concept of power conservation and acknowledged the energy crisis until 2016. The concept is required of all energy users to reduce their electricity consumption, intensify energy efficiency and cautiously proceed with new projects. The generation of energy results in by-products called ?green house gases? (GHGs). To make a positive response to climate change and their effect on the environment, every energy user must ensure efficient energy use through technical and administrative means referred to generally as energy savings. This paper identifies mine ventilation engineering, in particular the electricity consumed by main fan units, as an area of potential energy savings. For a major mining company, electricity consumed by main ventilation fans alone can be in the order of 120 MW. Although a known fan engineering technique but scantly applied technology identified as the Hermit Crab can be seen as a ?quick win? project, due to its success in other industries such as cement and steel. The ?Hermit Crab? technique® involves upgrading or replacement of an impeller - whatever its origin - with a design impeller to suit the actual ventilation requirements, resulting in increased fan efficiencies. The cash flow benefits associated with a case study and its rollout of this technology have been calculated. For a 10% increase in main fan efficiency, would have a net present benefit of US$ 16.08m over 10 years. With the inclusion of carbon credits, this benefit rises to US$ 29.40m in total. Application of other available technologies, viz., composite materials, ventilation-on-demand and variable speed drives are discussed.

Jan 1, 2009

By Arthur E. Belton

Ever since the industrial Revolution both major and small companies have put much emphasis on the use of incentives to compensate top management for extra effort and extra skill. For many years industries have also provided hourly rate employees with incentive plans. More recently incentive plans have been extended to include the "front line" supervisors. Many companies have what are called Christmas bonus or profit-sharing plans. The incentives for foremen in mining, which we shall discuss, differ from such bonus plans in that the incentives are paid on a definite measured performance for each individual, and thus directly reflect his effort and skill. What is the objective for paying incentives? The objective for any part of an industrial Engineering Program is to increase productivity and reduce unit cost. The unit cost must include the entire cost of the program. From what base do we start an incentive plan? One should think of art incentive program as the top rung of the Industrial Engineering ladder. Therefore, a company must take several steps before reaching this top rung. The following steps are necessary:

Jan 1, 1960