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By P. H. Tumialán

El yacimiento de tungsteno de Pasto Bueno, ubicado al norte del Batolito de la Cordillera Blanca, en Ancash se emplaza en las fillitas de la formación Chicama y en el stock de cuarzo monzonita del Terciario. En este sentido, el distrito minero ha sido fallado antes de la mineralización y posterior a la misma con fallas modernas e inversa. Por ello, el objeto del texto es describir los controles de mineralización a través de la división del distrito en tres zona la zona de Consuzo, cuyas vetas principales son Loreto, Auxilio, Sta Rita; la zona de Huayllapón, cuya veta principal es Chabuca, y la zona de Huaura donde se estudiará a la veta del Consuelo.

Oct 14, 1980

By R. L. Smith, J. L. Rutherford

ZONE refining, as developed by W. G. Pfann,1 has been used extensively for the purification of semiconductors. This method has made it possible to obtain the extremely high purity material necessary for the transistor industry. It has also been utilized to some extent for the purification of relatively low-melting-point metals. However, very little attention has been given to reactive, high-melting-point materials, with the exception of silicon. For this element, it has been necessary to use the floating zone technique in order to avoid contamination from the crucible containing the melt. The method is one in which a narrow molten zone is formed in a vertical rod by induction heating. The molten zone is supported between the two solid sections of the rod by surface tension. It is then moved longitudinally along the rod in order to effect a redistribution of solute. This technique has an advantage over the horizontal boat method, since crucible contamination is avoided. It has the disadvantage of being a much more difficult technique than zone refining in a crucible. Furthermore, it is necessarily a slow process, since only one zone at a time can be formed. However, the floating zone process offers a means of obtaining high-purity metals that are either not available, or can only be obtained in powder or pellet form as the result of complex chemical or electrochemical methods. It should be emphasized that the process is not effective in removing all impurity elements. Those that cannot be redistributed in an ingot during zone melting must be removed by some other means. Very little is known of the prope~ties of very high purity reactive metals such as iron, titanium, zirconium, beryllium, etc. It is quite likely that trace elements in such metals can affect their properties drastically. Therefore, one of the primary objectives of this work is to study the properties of metals which have been obtained in the purest form available and then zone refined. Trace elements can be introduced in a variety of ways, such as by inserting wafers between solid portions of the ingot to be melted, by placing the

Jan 1, 1958

By I. A. Ettlinger

THE formation that the writer has chosen to call "The Central Arizona Batholith" is included in the Globe, Miami, Ray, Pioneer, Troy, and Silver King mining districts. Its extension to the southeast is in the Banner mining field. Basing his argument on what is known of batholithic intrusions, the author offers reasons for considering all these granitic outcrops as parts of a single great mass of plutonic rock. The United States Geological Survey has subdivided this area into three -quadrangles-the Globe, the Ray, and the Florence. Of the first two, geologic atlases1 have been published, but of the last, the topographic map alone is available. These mining districts include such prominent present-day producers as Inspiration, Miami, Old Dominion, Arizona Commercial, Iron Cap, Superior and Boston, Magma, Belmont, and Ray Consolidated. Among those well known in the past are Silver King mine and Gibson mine. Fig. 1 is a geologic map of the Central Arizona Batholith region. F. L. Ransome's excellent work on The Copper Deposits of Ray and Miami, Arizona,' is of great value to all workers in those districts. His geologic map for the Ray and Globe quadrangles has been incorporated in Fig. 1, and the stratigraphic names employed are those first applied and defined by him in his pioneer work in this region. The purpose of this paper is to show that the ores are related to post-Carboniferous granitic intrusions; that while there does not seem to be any adequate explanation for the distribution of all the igneous stocks, a preexisting structure does appear responsible for at least the location of the largest igneous stock of the region; that the principal producing vein mines are located in the sedimentary rocks in the roof of this batholith, while the disseminated copper deposits are found bordering the lower portions of the batholith exposed by erosion; that primary zoning is illustrated not only on a broad (district) scale but also on a small (individual

Jan 1, 1928

By R. Fred Pena

The Tower Mill has proven to be a grinding machine with a demonstrated application flexibility. Variations in applications have proven to be numerous. This mill was originally intended for fine grinding applications. Subsequent testwork and installations have demonstrated the mill can be utilized in place of ball mills as secondary mills. The following lists a few of the circuits tested: 1. Tower Mill secondary receiving feed from a primary SAG mill grinding stage. 2. Tower Mill as tertiary grind unit following a rod mill/ball mill. 3. Tower Mill as secondary grind unit following a primary ball mill. 4. Tower Mill as a limeslaker. 5. Tower Mill grinding as a primary unit taking limestone crusher discharge. Applications demonstrate the mill is energy efficient and is sensitive to the following consideration: 1. Circuit chosen. 2. Top size of feed. 3. Product size required. 4. Classification equipment performance. 5. Media size required. 6. Media type required.

Jan 1, 1986

By Wilson AC

Permian coal from Western Australia's only producing coalfield at Collie is the dominant fuel used in generating electricity for the State's interconnected grid. Collie coal is sub-bituminous, non-coking and has a low ash, medium volatiles and high moisture content. The seams were laid down in a fluvial basin which extended beyond the Collie Basin and included the Wilga and Boyup Brook Basins at least. Adjacent parts of the southwest Yilgarn Block are prospective for Collie-type basins. In the past few years significant deposits have been delineated within the Perth Basin, specifically on the Vasse Shelf and in the Hill River area. In the former area high quality steaming coals are correlated with the lowest coal bearing member at Collie. The seams are amenable to underground mining and because of their high quality, the coal may have export potential. Sub-bituminous coal deposits of Jurassic age are present in the Hill River area. Exploration has down-graded the prospectivity of the Carnarvon and Canning Basins for sub-bituminous near-surface coal deposits. Tertiary lignite deposits are present in palaeo-drainage systems in the southern part of the State and their potential for development is being evaluated.

Jan 1, 1986

By C. Strachan

This paper presents an evaluation of the tailings dam incidents included in the 1994 US Committee on Large Dams (USCOLD) Committee on Tailings Dams report. Also, comparisons are made to water storage dam incidents from USCOLD reports, as well as to more recent tailings dam incidents. The evaluation results show that tailings dam incidents result from a number of factors, including overtopping, static and seismic instability, seepage and internal erosion, and foundation conditions. The results also show that no particular type of tailings dam or operational condition is more susceptible to incidents. In addition, the results confirm that tailings dams should be located, designed, operated and reclaimed with a thorough knowledge of site conditions, mill operation, site monitoring and tailings characteristics.

Jan 1, 2002

By Darryl Amick, Keith A. Prisbrey, Lee E. Plansky

The problem addressed was to develop automated image analysis of metal welds to replace unreliable and costly 100% visual inspection. The objective was to evaluate neural networks combined with features from gray level surfaces. Photomicrographs of the welded seam in Zircaloy-4 channels used in nuclear fuel rod assemblies were examined. The methodology used was to select a set of morphological feature coefficients from Bessel Fourier morphological feature coefficients extracted from digitized photomicrographs. The selected morphological feature coefficients were then used to train a neural network. The approach was verified initially by successfully training a neural network using the known, secondary chemistry of the alloy welds. The results were good. The Bessel Fourier coefficients captured sufficient information from the metallographic images to distinguish weld quality. This approach has the combined advantages of compressing the images through Bessel Fourier coefficients and give the ability to rapidly process large amounts of data using neural networks.

Jan 1, 1993

By Noel S. Christensen

COBALT is a silvery white metal with a slight bluish cast, strongly resembling nickel in its appearance and properties, notably its resistance to corrosion, although its alloys with other metals differ quite decidedly in their properties from those of nickel. The name cobalt was derived from the German "Kobold" meaning goblin and this came to be applied to the cobalt minerals which, although they resembled ores, did not readily yield metal when smelted by the primitive processes available in the Middle Ages. Cobalt minerals were used as pigments by potters and glass workers before the Christian era. Cobalt blue glass was found in the tombs of the Egyptians and in the ruins of Troy, and many colors used by the ancient Greeks and Romans contained cobalt. The ancients were entirely unaware that the colors they used were caused by cobalt and the metal itself was only isolated about the middle of the eighteenth century by Brandt although the preparation of cobalt compounds had been carried on in a small way ever since the opening of the silver-cobalt deposits at Schneeberg, Germany, in 1470. The metal is fairly hard, with a density when pure of 8.81 in the cast state and 8.92 after working. The commercial grade of cobalt has a density of about 8.75 in the cast state. The atomic weight is 58.97. The Brinell hardness of the pure metal is 124; that of the commercial grade varies from as low as 100 to as high as 138, depend¬ing upon the impurities present. Pure cobalt has a sharp melting point at 1478°C. The tensile strength of the pure metal in the cast condition is said to be higher than that of any other pure metal. Kalmus gives it as 34,400 lb. per sq. in. for cast unannealed metal; the effect of annealing at 850 to 900°C. is to raise the strength slightly. The yield point is close to the ultimate strength and the reduction in area and elongation are both low. Mechanical working raises the tensile strength of pure cobalt rapidly and in the form of wire it will be over 100,000 lb. per sq. in. The presence of small quantities of carbon in the commercial metal raises the tensile strength to as high as 61,000 lb. per sq. in., the reduction in area and elongation being raised at the same time to approximately 20 per cent.

Jan 1, 1933

By Joseph L. Condon

The U.S. Department of the Interior, Bureau of Mines, is doing research on methods to obtain premining information on problems such as detection of old mine workings, abandoned oil wells, channel sands, faults, and other geologic features that are undesirable from a production or safety aspect. Techniques being developed to acquire the necessary information include seismic and electromagnetic. The seismic methods include high-resolution seismic and acoustic methods applied from the surface and inseam channel waves applied under- ground. The electromagnetic, or radar, methods are applied from the surface, from boreholes, and from the working face underground. All of these methods are useful under certain site-specific conditions, but none of these methods is universally applicable for all mining conditions.

Jan 1, 1980

By E. S. Moore

"The Centre of the silver-producing section of the Gowganda area lies about 55 miles northwest of Cobalt, and the village of Gowganda is 71 miles by road from New Liskeard. The geological similarities of the Gowganda and Cobalt areas led prospectors westward from the rich Cobalt field, first to Elk Lake and then on to Gowganda, where mineralization was found in 1907. A year later many showings were found, and rich hand-picked ore was shipped. Most of the ore has come, however, from two mines, both of which are still operating; the Miller Lake-O'Brien, which was purchased by Siscoe Metals of Ontario Ltd. in 1945, and the Castle-Trethewey. The annual production of these two mines runs over one and one-half million ounces of silver and considerable cobalt. The total production of the camp has reached about 32,000,000 ounces of silver and a large amount of cobalt, the total not recorded.General GeologyThe general geology of Gowganda is in many respects much like that of Cobalt. There are areas of Keewatin basic and acid Javas mixed with tuffs and basic intrusions. These rocks are deformed and partly altered to schists, and have been intruded by some Haileyburian basic and ultra-basic rocks and by Algoman granite. These were followed by a large number of porphyritic Matachewan quartz diabase dykes. After a period of extensive erosion the Huronian sediments were deposited on a pene-planed surface over all the older rocks; these sediments include large quantities of conglomerate (partly tillite), quartzite, and greywacke. The Keweenawan rocks include the Nipissing quartz diabase sill, later quartz diabase dykes, and one long olivine diabase dyke, the latest Precambrian rock. The area has been extensively glaciated.Structural FeaturesThere has been little folding in the area since the Algoman batholiths were intruded, and the Huronian sediments lie nearly flat, with dips of 10, 15, or rarely 25 degrees. The Matachewan dykes show a remarkably uniform, nearly north strike, indicative of east-west tension when they were intruded. On the other hand, the dykes later than the sill strike nearly east, tangentially to the northeasterly and northwesterly strikes of the Miller Lake basin."

Jan 1, 1949

By N. S. Wagner, R. S. Mason

The production of lightweight aggregates in Oregon is a new industry, and, like all new enterprises, it is suffering from growing pains characterized by numerous, small operations some of which flourish for a short time and then cease altogether. Norinally all industrial mineral products are produced in a highly competitive atmosphere. At the present time this condition does not exist to a very marked degree in the state because as yet producers have not saturated the constantly expanding market. This paper has been prepared with the intention of outlining very briefly the current status of the various products now heing used as lightweight aggregates in Oregon. The present piche will surely change, perhaps quite radically within even a short space of time. Lightweight Aggregates Used in the Northwest PUMICE Interest in Oregon pumice is not new. Deposits are abundant. Successful development, however, dates only from 1946. During 1948 a total of nine operations was engaged in full or part-time production of aggregate. The postwar building boom and increased public consciousness regarding the value of insulation are the immediate reasons behind the current development. Just how firmly this production of pumice aggregate may be established is something which cannot be foretold at the present time. Much will depend upon how successfully the pumice aggregate construction already installed stands the test of time. Some fine pumice aggregate products have been made and it seems probable that because of its unique properties a certain demand for pumice aggregate will continue in the future. Fire-proof, rodent-proof, decay-resistant properties supplement the lightness in weight and insulation properties of pumice aggregate products in rendering them particularly ideal for many types of construction. In addition there has been fabrication in the form of reinforced fence posts, street markers, and similar products of a specialized-product nature and these are not to be overlooked in terms of future production. Also pertinent to how soundlj pumice aggregate production is established will be possible future competition with other lightweight aggregates. However, this situation will be governed largely by competitive costs of production and marketing. For its present use, which is almost exclusively limited to the manufacturing of building blocks, the market for Oregon pumice aggregate has been extended from the mining area around Rend and Chemult to points as far distant as San Francisco and Seattle. Naturally enough the bulk of the production goes to the Portland and eastern Oregon consumers. Shipments are made by both rail and truck. Early in 1947 the State Department of Geology and Mineral Industries made a canvass of all pumice producers in the state. The production for 1956 amounted to 26,614 cu yd and was valued at $13,649 at the plants. The United States Bureau of Mines estimates the production for 1947 as 33,240 short tons valued at $111,380. This is roughly 65,000 cu yd. No data are available for the 1948 production but it is understood to exceed that for 1947. The Oregon pumice occurrences originated largely from the eruption of Mount Mazama, the name of the formerly active volcano and the location of Crater Lake. Other lesser volcanoes throughout the area contributed to the present occurrences, however, and it has been estimated by Moore' that the pumice deposits cover an area of some 3500 square miles. This area lies east of Crater Lake between Bend and Klamath Falls and embraces the southern portion of Deschutes County, the northern part of Klamath County, and the northwest corner of Lake County. Thickness of the pumice ranges from thin skims to local thicknesses of as much as 30 to 40 ft. Fragment size also varies greatly. Any attempt to describe the situation by giving screen analyses would be confusing because of the wide variations to be found in all area of this size. The picture can best be summed up by stating that places showing great variations in fragment size can be found if a search for extremes is made. For mining purposes in connection with aggregate production, it call be stated that miles and miles of pumice exist in which the fragrnent sizes range from an inch or so downward. The usual color of the pumice is a light gray to off-white. A typical pumice analysis shows a silica content of about 69 pct, alumina 15 pct, and sodium oxide about 5 pct. Potash, lime, and water are the next three most abundant constituents, running just a little over 2 pct each. Iron oxides are fairly constant at 2.75 pct. Titanium, manganese, magnesium, and phosphorus occur in amounts of less than 1 pct. All of the foregoing substances are combined as a glass exhibiting cellular structure. The weight of crushed but otherwise pit-run (undried) pumice runs around 1100 Ib per cu yd according to figures furnished by various producers. The minimum and maximum weights per cubic yard reported are 1050 and 1400 lb, respectively. The 1400 lb per cu yd pumice contrasts with the pumice from most of the other

Jan 1, 1950

By W. L. Hollinshead

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

Jan 1, 1999

By Toru Nakao

Fujiwara Quarry had been operated by the "Glory-hole Benchcut" mining system. But because it became difficult to meet the expanding demand by this system, "Central- shaft MCP" mining system was introduced in 1979. This MCP is equipped with a hydraulic walking system manufactured for the first time in Japan. Nowadays "Central-shaft" mining is the common method at limestone quarry in Japan. In this method crushing facilities are usually installed at the bottom of the shaft. But at this quarry, MCP was adopted and installed on the quarry surface. Many MCPs are operated in foreign countries, but in Japan few examples exist. Normally, Japanese limestone deposits lie in high mountains, which is obviously inconvenient for MCP to walk in and around the quarry. This difficulty, however, was overcome at this quarry, and MCP has been operated satisfactorily and efficiently for about 2 years after it was installed. In order to overcome the difficulty, in "Cen¬tral-shaft MCP" mining system, two mining methods are employed, the one is "SLICE-DOWN" mining method, and the other is "BLOCK-CUT" mining method.

Jan 1, 1982

By Wallace Ralston

The East Texas area includes the northeast 38 counties of the state of Texas. It covers all, and extends beyond, the borders of what is commonly described as the East Texas Basin. It is one of the most important oil and gas-producing areas of the Mid-Continent Province. It includes four important oil fields—Van, East Texas, Cayuga and Long Lake— and the recent extension of Rodessa field into Cass County, Texas, may prove to be of major size. Four commercial gas fields are in this area— Bethany, Waskom, Cayuga and Long Lake. Up to January, 1936, all of the oil has been produced from the Upper Cretaceous formations, and most of that from the basal member, the Woodbine sand. Gas is produced from both the Upper and Lower Cretaceous formations. Development in Fields East Texas Field.—This field continued to dominate the drilling and production situation throughout the United States. There were 4036 wells completed in this field during 1935; that is, 365 more wells than were completed during 1934. Drilling activity was due to close spacing of wells and the addition of 10,000 acres to the field. The field is now drilled to a density of one well to 6½ acres, which is certainly more wells than necessary for economic production of the field. The close spacing of wells is due mostly to the type of proration, which is per well allowable based on a potential test, and does not take acreage into consideration, and also to the numerous small acreage tracts such as town lots and excess strips. The field now has 19,519 producing wells. The allowable production for the field during 1935 was 161,118,659 bbl.; estimated production, including illegal or "hot oil," was 174,200,150. The illegal production of oil gradually decreased throughout the year, until an estimated low was reached of 20,500 bbl. daily during the months of November and December. The price of oil remained at $1.00 per barrel throughout the year. As stated, about 10,000 acres were added to the field during the year, making a total of 128,000 productive acres. There is a possibility that

Jan 1, 1936

By Jairo Romero

En la Industria Minera, la roca puede considerarse como la primera fase de conminución. Las fases de estas son mecánicas y consisten en etapas consecutivas de chancado y molienda para la reducción del tamaño de partícula. La energía total de la conminución mecánica depende del tamaño de la partícula y de la resistencia del material a la molienda. Por lo general, el primero se cuantifica por la distribución del tamaño de partícula o uno de sus KPI (como los diámetros X50 o X80), mientras que el segundo por el Índice de Trabajo (WI), que representa la cantidad de energía necesaria para reducir el tamaño de partícula de una cantidad determinada de material al diámetro equivalente deseado (usualmente expresado en kWh / t).

Sep 1, 2017

This paper concerns a pragmatic approach to a problem that is common to many operations in the mining industry: how, over the short-term, to grasp the extent and distribution of long-term financial risk from environmental causes and reduce these risks strategically, in order to maintain stability and flexibility in the operations. Surprisingly, many companies operate without an environmental master plan or tools that can help managers measure and reduce financial risks. Such companies may be subject to unknown unacceptable financial risks from environmental causes. While many companies have some kind of internal system of environmental standards, it is often the case that such systems have uneven or limited effect, and offer no opportunities for visualising, measuring or managing aggregate financial risks from environmental causes. `Aggregate risks' are defined here as the calculated total expected financial costs to a company, or a subdivision of a company, from environmental causes at nominated operations over a defined time period. Aggregate risks take into account the type and magnitude of an environmental problem set, the likelihood of occurrence, and the time frame during which the problems will develop or solutions are required. For the large corporation, the 'amount of' aggregate environmental risk is a statistic that can be managed, along with other financial parameters, at the corporate level to improve the stability and predictability of operations, and protect the interests of shareholders. This paper concerns development of a management framework and a tool for the large corporation that responds to the need for managing aggregate environmental financial risks. The logical framework proposed to overcome the need for strategic vision is the Environmental Master Plan, and this is described in the next section. The analytical tool proposed to measure aggregate risks and provide relevant data and insights to managers, is called an Environmental Risk Management Information System, and its mechanics are described in a subsequent section.

Jan 1, 1994

By John S. Summer

The induced polarization (IP) method of geophysical exploration is capable of detecting even small amounts of metallic luster minerals in a rock mass. Consequently, in the years since discovery, IP surveying has become the most popular ground geophysical survey method. It is not too difficult to understand many applications of IP surveying as used in the search for mineral deposits. However, the basic theory of the IP phenomenon is not well developed or understood, and there has been some disagreement on fundamental concepts. In order to most effectively apply the IP method in the field it is necessary to know the physical characteristics of the sought-for deposit including its size, shape, depth, and electrical properties. With this information an optimum IP search arrangement can be devised and one could use the best possible electrode interval, type of array, and line spacing. With uncertain target characteristics as encountered in the real world, geological guidance must be used to help direct an optimized IP survey.

Jan 1, 1972

Bismuth, "the green metal," has become an important substitute for lead. The uranium industry was never really dead, anti-nuclear activists just wanted the world to think it was. And diamonds are fast becoming a miner's best friend. These commodities and others were discussed in May 1997 at the 47th Annual Minerals Processing Division meeting, held at the Broadmoor resort in Colorado Springs, CO. The meeting was put on by the SME Colorado subsection and was attended by about 115 people. In addition to the above three commodities, attendees learned more about the state of the copper industry, as well as lead and zinc and gold and silver. The program also included discussions of molybdenum, platinum and project financing. The following is a summary of some of the presentations.

Jan 1, 1997

By A. A. Peshkov, N. A. Matsko, K. N. Trubetskoy

It is possible to divide the general objectives of a company into two components: maximum expected profits and viability over time. These components are designed to maximize the companies value over time. The evaluation of a project includes both a discounted cash flow (DCF) analysis and a risk analysis. The DCF analysis determines whether the project should be accepted or rejected, and the risk analysis helps to forecast possible deviations from the original estimates. However, the results of both methods do not allow for a quantitative comparison between the main objectives of the venture, and they do not resolve the issue of whether it is advisable to sacrifice immediate profits for future profits. This paper attempts to resolve this issue. The present research was carried out on mining projects with different waste-extraction schedules. Calculations were made using the US Bureau of Mines' usage-of-costs model. Russian experience in open-pit mining is reflected in this paper.

Jan 1, 1996

By Pierre Mousset-Jones, Felipe Calizaya

The design of an auxiliary ventilation system for long underground openings (drifts, ramps and shafts), often requires the installation of multiple fans. The fans are installed in series and separated from each other by rigid ducts of fixed or variable length. However, problems relating to excessive leakage often occur, with each project representing a unique problem requiring an efficient solution. In this study, a method to determine the design parameters of an auxiliary ventilation system is presented. The method is based on the principle of partitioning a long ductwork into segments of finite length and solving the resulting networks separately. Specifically, the method is developed to solve two types of problems: constant fan spacing, and constant fan size. In the former, the fan spacing is fixed, and the problem is solved for fan sizes. In the latter, the problem is to solve for fan spacing. An example is used to illustrate the method.

Jan 1, 1993