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By John Hays Hammond

The Transvaal comprises about 120,000 square miles (nearly • the size of the United States Territory of New Mexico). Besides the famous Witwatersrand, which will here be de scribed in detail, there are two quartz-mining districts of some importance, viz., Lydenburg and De Kaap. The Lydenburg district first attracted attention in 1876, when the alluvial deposits of that section began to be exploited. At a later period vein-rnining was started, and at the present time several companies are operating in that district. The product in 1898 of five companies, running 137 stamps, was 154,560 tons of ore, yielding 108,884 crude ounces of gold (an average of 14.09 dwt. crude gold per ton) valued at £392,378. The De Eaap gold-fields were discovered in 1884. In 1898, seven companies, running 200 stamps, produced 89,760 crude ounces of gold, valued at £314,792. I. Mining Titles in the Transvaal. The mining laws of the Tranuvaal are most excellent in char acter, and while the claims cover every square foot of land for an area of nearly 40 miles long by from 2 to 3- miles wide, there have been practically no conflicts over extra-lateral rights. Notwithstanding the change in the political status of the Transvaal likely to follow the present war, it may be coufi dently assumed that the main features of the mining law of the South African Republic will be retained, and certain op pressive featureu of monopolies, etc., bearing with special weight on the mining industry, will be abolished. The dynamite mo nopoly was one that bore most heavily on the mining industry; and, according to the Reports of the State Mining Engineer, explosives, including fuse and detonators, amounted to nearly 10 per cent. of the total working costs of the mines. Further more, it was impossible to obtain the proper quality for the most economical working, and often 80-per-cent. or 40-per-cent. gelatine had to be used- in many instances where 60-per-cent.

Jan 1, 1902

By Cesar Montoya, Yarmin y. Taborda

Indagar sobre la operatividad de la minería en Colombia es una acción mayúscula, pues esta no se observa solo desde la arista económica para la generación de beneficios a determinada población, sino también de acuerdo con su historia, personas que la operan, formas de desarrollo y otros. La investigación se desarrolló en 15 minas artesanales ubicadas en los sectores: La Ferrería y la Cancha del municipio de Amagá en Antioquia. Se ejecutó con un enfoque cuantitativo no experimental de tipo correlacional y permitió la descripción de características propias de las minas y la identificación de los niveles de desarrollo frente al Sistema de Gestión de Salud y Seguridad en el Trabajo.

Desde tiempos históricos, el plomo es uno de los más antiguos metales usados por el hombre, y como tal, la metalurgia exige propiedades más definidas acerca de este metal,. Por tal motivo, el objetivo del texto se basa en describir los resultados de los análisis de 10 marcas de plomo, junto con el análisis promedio del producido por la Cerro de Pasco Corporation, para así impulsar la calidad del dicho metal como producto y encontrar las impurezas que influyen en la formación del "dross" y refinación. Si bien el plomo contiene un circuito de refinamiento en su proceso, la recompensa por el producto depurado no ha sido satisfactoria dado el costo y tiempo de mejora para estos productos. Por ello, se evaluó el estado del plomo de la empresa Cerro de Pasco, paralelamente con otros 20 lingotes de otras compañías, para asi mejorar la condición del producto frente a la competencia del mercado. Los resultados de esta evaluación señalaron que los lingotes al alcanzar menor altura, se exponen a condiciones de calor y humedad atmosférica, logrando que se condense el agua dentro de las cavidades que se comunican con ella. El problema surge cuando en el proceso de transporte, los lingotes son afectados por las lluvias e introducidos en un baño de metal, ocasionando una explosión. Entonces, se realizó pruebas de moldeo a diferentes temperaturas, utilizando moldes preparados, sin encontrar resultados satisfactorios. De otro lado, los examenes de los 20 lingotes de las 10 marcas de plomo de otras compañías, indicaron que todas las marcas de plomo sufrían del defecto de cavidades, en diferente grado, pero que la calidad del moldeo estaba en las formas de calentamiento de la parte superior del producto. En consecuencia, se diseñó en la Cerro de Pasco Corporation, una máquina para el diseño del moldeo, de forma que el lingote se conserve al realizar el enfriamiento desde el fondo hacia arriba, sin alterar el proceso de solidificación y mantenga la calidad BBTT standarizada.

Jul 20, 1959

By C. A. Jermy, B. J. Venter

Excessive build-up of methane and water pressures was identified as the leading cause of some Q/the roof falls in a coal mine in the eastern Transvaal. In order to characterize the migration of the methane and water into and around the mined coal seam, a laboratory investigation of the permeability of the roof strata was undertaken. The aim of the investigation was to correlate changes in the fades with changes in permeability to enable the prediction of possible zones of pressure buildup. The tests were carried out on samples from borehole core that had been obtained from the roof strata as part of the mine exploration programme. Permeability measurements were then conducted under atmospheric and triaxial-stress conditions. For the tests under atmospheric conditions, a modified Ohle cell was used and, for the tests under triaxial-stress conditions, a modified Hoek cell was used. The liquid equivalent permeability?s of the different samples were obtained by use of ASTM D4525- 85, and these were then used as a basis for comparison. Facies type, i.e. grain size, was found to have an influence on the permeability but, owing to the variable nature of the sediments, a range of permeability rather than a specific permeability value was associated with each type of Jades. The measured permeability was bound to decrease with an increase in gas pressure. The liquid equivalent permeability was bound to increase with an increase in grain size for the coarser-grained Jades, and to decrease with an increase in grain size for the finer-grained types. The application of an external stress regime to the sample was bound to reduce the permeability, but the amount of the reduction depended on the type of stress. The permeability was also found to depend on the recent stress history of the sample. The authors conclude that the methods described are useful for the correlation of facies type with permeability, but that the results are sensitive to changes in locality.

Jan 1, 1994

By C. S. Simons

The conversion of a successful research and development effort into a money-making business venture requires careful attention. Problems of a business nature, such as market size, product selling price, raw materials and fuel availability and cost, financing factors, local and national taxes, licensing arrangements, etc. must, of course, be considered and resolved. In addition, the technical questions involving the scale-up of pilot plant or laboratory results to the full-scale plant must be resolved in order to avoid the financial disaster that attends a major delay in the startup of a commercial facility. The very difficult and demanding task of providing the interface between the research laboratory and the profitable metals processing plant will be discussed with examples from the author's extensive experience. After I had accepted the invitation to present a paper on the above subject of the interface between R & D and production operations, I began to give some serious thought to the subject. The program chairman had told me, in conveying the invitation, that what the committee had in mind was a discussion of positive and negative, forces in that interface, based on "gray-hair" experience. I am, therefore, at least physically qualified! My first reaction was one of mild shock; after over twenty years in the direct pursuit of the conversion of research and development findings into plant operations, I had never tried to sort out my , experience into a formal system of DO'S and DON'TS for the edification of posterity. However, after a little further reflection, I realized that this carries no stigma. No one has been able to formulate such a set of rules, and it is not really very likely to be done. Particularly if they are to be practical. I shall therefore settle for a more modest goal; I will simply discuss the factors that I have come to believe are the most critical in insuring that re- search and development results are converted into successful operation.

Jan 1, 1973

By Ancel St. John

At the New York meeting of the Institute of Metals Division in February, 1927, Jeffries and Tarasov presented a paper on Tungsten and Thoria,' in which the experimental facts were interpreted in accordance with the prevailing point of view that the thorium is present as the oxide, thoria. In discussing that paper the writer of this article stated that his own investigations, which had been unavailable to Messrs. Jeffries and Tarasov, showed that the so-called "thoriated" tungsten filament failed to disclose any sign of the oxide when subjected to X-ray diffraction analysis, but did give plenty of evidence of the presence of metallic thorium and, in certain cases, of a material believed to be an alloy of tungsten in thorium. Since these results were completely at variance with the results reported in the paper under discussion and with other papcrs which had preceded it from time to time in the past, it was felt that further discussion should be withheld until the new evidence could be presented adequately. Arrangc-mcnts were therefore made to present that evidence at this meeting. Material Examined The material exalllined was high-ernission filament such as is used in radio tubes, supposed to contain about 0.75 per cent. thoria. The actual analysis was not stated. Scope of the Investigation The investigation was undertaken because of a feeling that the thorium present in filamentary material of this type exists as metallic thorium or as an alloy of thorium and tungsten and not as the oxide. Attention was therefore directed to determining: 1. The minimum amount of thoria detectible in a mechanical mixture of thoria powder and finely divided tungsten. 2. The amount of t.horia detectible in the filament. 3. The condition of any thorium present in other form than as thoria. 4. The amount of thorium dissolved in the tungsten.

By Jerry C. Tien

This paper investigated the airflow pattern in the working face area during a cross-cut development. The study used a 10:l scale face model and a mock continuous miner. Results showed that keeping up the line curtain is essential in order to avoid recirculation and to control respirable dust and methane, in the face area.

Jan 1, 1989

By M. W. Strong

The technique of handling drilling muds varies somewhat, partly because of personal factors but mainly because of differences in formation, the type of problems, and the general drilling conditions in different localities. The much greater depths to which bore holes are now carried have made necessary closer attention to and great modifications of all aspects of drilling-mud technique. Increased depth means smaller hole, smaller drill pipe, smaller clearances, higher pumping pressures, higher differential pressures between shows and the mud column, less accurate control of the weight of the mud column, delayed receipt of formation data, and poorer samples. It means longer delays and greater hazards in rectifying mistakes or dealing with accidental occurrences. Equipment on a larger scale is necessary and more pains must be taken with layout. Lastly, the budget costs of raw materials have risen to high figures and economy of time and of direct monetary expenditure have come to mean much more than formerly. A mud laboratory is now part of the essential establishment of a modern oil field and to it current problems can be submitted for the most thorough investigation. The detailed chemical properties of all materials purchased or quarried have to be investigated. Detailed data on the physical properties have to be ascertained and research on improvement of material and its most efficient use has to be carried out. In this paper will be discussed the main mud problems of Iran, some of which are peculiar to local conditions while others are of the general type common to all workers in this subject. Underground Conditions In deep wells in Iran the normal overburden may consist of: (1) up to several thousand feet of marls with interbedded sandstones and limestones of varying porosity and permeability; (2) beneath this a chemical series of rock salt and anhydrites, containing various marls and thin limestones,

Jan 1, 1939

By M. W. Strong

The technique of handling drilling muds varies somewhat, partly because of personal factors but mainly because of differences in formation, the type of problems, and the general drilling conditions in different localities. The much greater depths to which bore holes are now carried have made necessary closer attention to and great modifications of all aspects of drilling-mud technique. Increased depth means smaller hole, smaller drill pipe, smaller clearances, higher pumping pressures, higher differential pressures between shows and the mud column, less accurate control of the weight of the mud column, delayed receipt of formation data, and poorer samples. It means longer delays and greater hazards in rectifying mistakes or dealing with accidental occurrences. Equipment on a larger scale is necessary and more pains must be taken with layout. Lastly, the budget costs of raw materials have risen to high figures and economy of time and of direct monetary expenditure have come to mean much more than formerly. A mud laboratory is now part of the essential establishment of a modern oil field and to it current problems can be submitted for the most thorough investigation. The detailed chemical properties of all materials purchased or quarried have to be investigated. Detailed data on the physical properties have to be ascertained and research on improvement of material and its most efficient use has to be carried out. In this paper will be discussed the main mud problems of Iran, some of which are peculiar to local conditions while others are of the general type common to all workers in this subject. Underground Conditions In deep wells in Iran the normal overburden may consist of: (1) up to several thousand feet of marls with interbedded sandstones and limestones of varying porosity and permeability; (2) beneath this a chemical series of rock salt and anhydrites, containing various marls and thin limestones,

Jan 1, 1939

By D J. Cronin

Alcoa World Alumina AustraliaÆs Huntly and Willowdale bauxite mines are located in the Darling Range of South Western Australia, which places their operations within PerthÆs surface water supply catchments. These catchments supply Perth with its highest quality drinking water. With the decreasing rainfall trend of recent years catchment yields to water supply reservoirs have reduced to such an extent that water use restrictions were necessary in Perth for 2001, 2002 and 2003. Protection of catchment water quality and water use conservation are crucial issues for AlcoaÆs operations within the Darling Range. Alcoa has been conducting bauxite mining activities in water supply catchments since the mid-1960s. During that time Alcoa has worked closely with the relevant State Government water and environmental agencies to ensure that its operations do not adversely impact catchment water yield and water quality. Monitoring and research have shown that Alcoa has the necessary environmental management systems in place to ensure it can continue to operate in a sustainable manner within water supply catchments. AlcoaÆs mines reduced the volume of water taken from public water supply catchments by 24 per cent in 2002, compared with 2000. This success has had an added benefit; Alcoa does not need to develop a new water source for its Huntly Mine. The conservation measures implemented to reduce water use include: increasing water recycling, using chemical additives for haul road dust suppression, conducting water audits, reducing water demand, monitoring water use, promoting water use targets and training staff in water conservation.

Jan 1, 2003

By C. Anderson

Most applications of copper metallurgy are geared towards primary production. However, as recycling of materials is a growing industry, one future facility will rely on copper metallurgy as a means of processing precious metals. This paper will discuss the derivation of the proposed copper pyrometallurgical and electrometallurgical unit operations to be utilized in industrial recycling of secondary precious metals.

Jan 1, 1999

Iron and steelmaking slags have been utilised for a century. All dumps are now exhausted. Because of constraints in establishing new stock yards, all slags have to be utilised immediately. At present, this is being achieved. Only in a situation where there is an increase in pig iron and crude steel production, together with the impact of new residual materials competing from other industries can marketing problems be anticipated.

Jan 1, 1979

By Otto Sandoval Zea

En la actualidad, existen equipos que analizan los daños colaterales producidos por la voladura como el uso de sismógrafos, los que son aplicados para el control de los limites permisibles de vibración en construcciones superficiales, de forma que permiten realizar análisis de vibración en condiciones subterráneas (Minas) y establecer parámetros que generen un mejor diseño de excavación en el avance y producción. En esta perspectiva, el presente texto para predecir el daño generado por los explosivos y la reducción de los mismos, emplea el análisis vibracional, donde se determina un comportamiento de atenuación de la velocidad vibracional de partículas en función a la distancia y la carga operante* representado por una curva exponencial denominado “Ley de Atenuación de Vibración de Partícula”, que difiere según la calidad del macizo rocoso y la potencia del explosivo empleado.

Sep 14, 2009

By Peter G. Chamberlain

Novel and innovative mining methods are attracting the attention of mining engineers at an unprecedented level. Historically, the US mining industry has responded rather conservatively to new technology. The financial difficulties affecting the domestic mining industry in the early 1980s changed attitudes toward new technology. The market contraction during that period, coupled with an expanding world mine capacity, created a serious oversupply of many raw mineral products. Many mining companies found that retaining a share of world markets while making a profit required drastic cost-cutting measures.

Jan 1, 2008

By D. D. Misra

Though computer simulation of coal beneficiation has been in use for nearly two decades the models used in the programs for the simulation of the crushing processes concentrate mainly on the size distribution. This paper suggests the use of an empirical equation approximating to the cumulative probability or error function for the simulation of the liberation process in coal crushing. The algorithm outlined here can be incorporated in a computer program already having a size distribution model.

Jan 1, 1989

By Michel Aubertin

Les activités minières peuvent produire de grandes quantités de roches stériles, qui sont typiquement entreposées dans des empilements de surface, au dessus la nappe phréatique. Ces haldes peuvent occuper une superficie de plusieurs dizaines d?hectares, et s?élever à plus de cent mètres. Pour des exploitations en roches dures, les roches stériles ont usuellement une granulométrie qui contient des particules de la taille d?un sol silteux jusqu?à des cailloux et blocs de taille métrique. La structure interne d?une halde construite sur une surface relativement plane comprend généralement deux zones principales. La première zone se trouve au coeur de l?empilement, et elle est formée par la présence de plusieurs stratifications subhorizontales (avec des couches denses et lâches) due à l?effet des équipements lourds qui compactent et brisent les grains. La deuxième zone se trouve aux endroits où les stériles ont été déversés en crête, par des camions ou des butoirs, ce qui induit une ségrégation des particules sur les flancs, le long de la pente. Selon la séquence de mise en place, la distribution granulométrique et la hauteur des bancs, un grano-classement plus ou moins développé se produit, avec les particules les plus grosses au bas de la pente et les particules plus fines au sommet ; on observe aussi une stratification inclinée due à l?avancement latéral du front de déposition. Ces éléments de la structure interne d?une halde influencent la distribution et le mouvement de l?eau (et de l?air). Pour évaluer la distribution des propriétés des matériaux dans une halde, on doit usuellement avoir recours à une combinaison de techniques qui fournissent des informations sur les caractéristiques hydrogéologiques et géochimiques des roches stériles. A cet égard, certaines techniques géophysiques sont particulièrement intéressantes car elles permettent une cartographie tridimensionnelle des variations des propriétés. Les informations obtenues de diverses techniques de mesures utilisées conjointement peuvent alors être employées afin de construire un modèle numérique qui permet d?analyser les écoulements non saturés de l?eau et le transport réactif des contaminants. De telles simulations aident à mieux comprendre la réponse de la halde dans son état actuel et futur, ce qui fournit des arguments pour ajuster la séquence de déposition pour élaborer le plan de fermeture et pour sélectionner la stratégie d?instrumentation et de suivi de l?empilement. La présentation inclura un survol des diverses techniques qui ont été développées afin de caractériser les propriétés des matériaux en laboratoire et sur le terrain, et pour obtenir un portrait global de la structure interne d?une halde. Des résultats additionnels sur la modélisation du transport réactif seront aussi montrés afin d?illustrer l?influence de la structure interne d?un empilement sur sa réponse hydro-géochimique et environnementale.

Nov 1, 2008

By Tucker A. J

An overburden blast utilising horizontal blast holes was successfully attempted at the Ulan Coal Mines during December 1991. The blast reduced operational problems and costs and improved dragline productivity in an area of that contains poorly consolidated sands and clays overlying very hard Permian strata.The fan shaped shot consisted of seven 250 mm diameter holes between 80 and 95 metres long drilled into the highwall face. The holes were loaded with ICI Powergel Gold 25606 bulk Emulsion explosive. The design powder factor was 0.15 kg/bcm for the total shot of 180 000 bcros and 0.44 kg/bcm for the competent Permian strata into which the holes were drilled. Fragmentation from the horizontal blast was comparable to areas conventual blasted. Following the success of this shot further shots are planned for this area.

Jan 1, 1992

New York Meets first Wednesday after first Tuesday of each month. J. E. JOHNSON, JR., Chairman EDGAR RICHARD, Vice-Chairman D. M. LIDDELL, Secretary, 7 Wall St., New York, N. Y. C. A. BOHN, Treasurer JOHN V. N. DORR LEWIS W. FRANCIS Boston Meets first Monday of each winter month. R. L. AGASSIZ, Chairman JAMES G. CARLETON, Vice-Chairman E. E. BUGBEE Secretary-Treasurer, Mass. Inst. of. Technology, Cambridge, Mass. W. E. C. EUSTIS G. A. PACKARD Columbia Holds four sessions during year. Annual meeting in September or October. W. H. LINNEY, Chairman OSCAR LACHMUND, Vice-Chairman LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. STANLY A. EASTON S. SHEDD Puget Sound Meets second Saturday of each month SIMON H. ASH, Chairman I. F. LAUCKS, Vice-Chairman PERCY E. WRIGHT, Secretary-Treasurer, 2012 L. C. Smith Bldg., Seattle. Wash. GLENVILLE A. COLLINS JOHN N. POTT

Jan 11, 1917

By John F. M. Sims, Charles B. Green

Introduction The gold rush to the Canadian Klondike and then to the Alaskan gold camps is legend to Americans. The early years of the century also saw flourishing hard rock mining at the famous Treadwell and Alaska Juneau gold mines and the bonanza Kennecott copper mine. Over the last two decades, rich discoveries of copper, cobalt, zinc, lead, molybdenum, tin, and silver have furthered Alaska's reputation as a storehouse of US minerals. Alaska may also contain large commercial deposits of chromite, platinum, and nickel. Yet in 1984, with the exception of the Usibelli coal mine and several hundred small placer gold mines, Alaska's mineral potential remains largely undeveloped. Uncertain 70s The 1970s were years of uncertainty for the mining industry in Alaska. The discovery in 1968 of a huge reservoir of oil and natural gas in Prudhoe Bay brought the land claims of Alaska's natives to national attention and focused interest in Alaska's resource wealth. The Alaska Native Claims Settlement Act of 1971 (ANSCA) created the regional native corporations and granted them selection rights to some 178 000 km2 (44 million acres) of Alaska's 1.5 Gin' (375 million acres) - about 12% of the state's land area. The native land selection process would take years. During this time, the status of much of Alaska's land was in question. Additionally, section d(2) of ANSCA provided for the conversion of an undetermined amount of federal lands into conservation units. These consist of parks, scenic rivers, national monuments, and wildlife refuges. The debate over the d(2) lands was long and acrimonious. National conservation groups lobbied to include as much acreage as possible within restrictive classifications, regardless of its mineral or energy potential. The process was polarized into a preservation-versus-development struggle. To many Alaskans, what was at stake was the ability to develop a viable independent economy, rather than an ongoing role as economic wards of the federal government. The resulting compromise was the Alaska National Interest Lands Conservation Act of 1980 (ANILCA). ANILCA resulted in the placement of some

Jan 1, 1985

By Beattie T. A

The ability of explosives to fragment rock has been assessed in small scale trials at the Granite Rock quarry, Baimsdale, Victoria. Three 65 mm diameter holes were fired simultaneously in a five metre bench, and the rock collected, screened and weighed. The mass of fines increased as the explosive strength increased in the series 30(10 ANFOPS

Jan 1, 1990