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By G. Lee, E. T. C. Spooner

"Molybdenum mineralization at Boss Mountain is hosted by the Triassic Takomkane quartz monzodiorite batholith and is associated with a Cretaceous monzogranite stock. Ore has been mined from a sheeted vein system that describes a partial annulus centred upon the apical region of the stock and from subvertical breccia pipes that emanate from the stock. Molybdenite precipitation is coincident with CO2 effervescence from a dilute (1.9 mole o/o NaC/ equivalent) hydrothermal fluid over a temperature range of 250°C to 370°C at a pressure of approximately 350 bars, interpreted to be greater than or equal to the lithostatic load and equivalent to a depth of 1.3 km or less.IntroductionThe chemical and thermal constraints on molybdenum transport and deposition to form molybdenum ore deposits are not well understood. To address this problem, the Boss Mountain mine in central British Columbia, operated by Noranda Mines Ltd., was chosen as a well-described (Soregaroli and Nelson, 1976), relatively small and simple example of a Cordilleran Mo~ deposit. It is situated on the northeast slope of Takornkane Mountain, 10 km west of the community of Hendrix Lake (N.T.S. 93A/2W; latitude 52°06'N, longtitude 120°56'W). Access is from 100 Mile House by nearly 90 km of road, the first 50 km of which are paved."

Jan 1, 1995

By Larissa Carolina Ferreira

O impacto das atividades do setor de mineração sobre o meio ambiente tem levado a estudos visando, tanto à utilização racional dos recursos naturais, quanto o tratamento de efluentes gerados durante os processos. A caracterização de efluentes é uma etapa importante, podendo apontar erros nos processos de beneficiamento, parâmetros em desacordo com a legislação ambiental e guiar etapas de desenvolvimento de técnicas do tratamento. Este trabalho consiste na caracterização de um efluente da etapa filtragem de uma mineradora de minério de ferro do quadrilátero ferrífero comparando os valores encontrados com as exigências da norma CONAMA 357/2005 e 430/2011, de forma a enquadrá-los na categoria de águas doces classe 1 e de lançamento de efluentes. O pH encontrado (9,8), turbidez (2133 NTU) e sólidos sedimentáveis (28mL/L), estão fora dos padrões permitidos e mostram grandes problemas em relação aos sólidos presentes na amostra. O diâmetro médio das partículas (8,54µm), indicou a predominância de partículas ultrafinas de difícil sedimentação. Os elementos majoritários Al, Fe, P e S, 0,296; 1,6; 0,218 e 26,5 mg/L, respectivamente, também apresentaram valores acima do permitido para água doce classe I. As análises indicaram que o efluente necessita de tratamento prévio para posterior descarte.

Aug 16, 2017

By Ebrahim Farrokh

Ghomroud water conveyance tunnel project is under construction using shield Tunnel Boring Machines (TBM) for a total length in excess of 50 km. Phase 1 of the project included 36 km of tunnel divided into four lots (1, 2, 3, and 4) of nine km each. Lots 3 and 4 of this tunnel for a total length of 18 km were combined into one award and have been constructed using a double shield (DS) TBM or one path system. Extreme ground convergence in some sections of the tunnel has stalled TBM performance in early reaches, due to face collapse and shield jammings. This paper presents the latest update on the tunnel progress and impact of ground convergence on machine performance based on the information obtained from field observations. Also, the method and results of tunnel convergence measurements were studied in conjunction with geological parameters and an attempt was made to correlate TBM operational parameters and ground convergence. The result of the analysis indicates a good correlation between machine?s operational parameter and tunnel convergence and can be used as an indicator of the potential for high rates of convergence. An early warning on ground convergence is essential for taking precautionary measures to avoid TBM jamming and related long delays and costs.

By Stanley A. Feitler

This Bureau of Mines report deals principally with the resources and economic aspects of feldspar in the United States east of the Mississippi River. Although in a strict sense, all phases of the feldspar industry affect its economic structure, emphasis in this study is on supply, demand, and marketing. Although feldspar was originally mined for use in the manufacture of pottery and other ceramics, the glass industry, which began to use feldspar in the mid-1920's, now consumes more than half of the annual output. Most mining is open cut, and the methods used are similar to those used in mining crushed b stone. Excess plant capacity has been chronic, and production is usually about 30 percent of capacity fur the industry as a whole. Since 1947, feldspar consumption has grown more slowly than the average for all U.S. industry. This has fostered intense competition, especially for the glass market. Prices have not kept pace with inflation, and profits are small. The trend of consumption through 1970 for glass feldspar is expected to be upward; less rapid in consumption of ceramic feldspar is anticipated.

Jan 1, 1967

By Stanley A. Feitler

This Bureau of Mines report deals principally with the resources and economic aspects of feldspar in the United States east of the Mississippi River. Although in a strict sense, all phases of the feldspar industry affect its economic structure, emphasis in this study is on supply, demand, and marketing. Although feldspar was originally mined for use in the manufacture of pottery and other ceramics, the glass industry, which began to use feldspar in the mid-1920's, now consumes more than half of the annual output. Most mining is open cut, and the methods used are similar to those used in mining crushed stone. Excess plant capacity has been chronic, and production is usually about 50 percent of capacity fur the industry as a whole. Since 1947, feldspar consumption has grown more slowly than the average for all U.S. industry. This has fostered intense competition, especially for the glass market. Prices have not kept pace with inflation, and profits are small. The trend of consumption through 1.970 for glass feldspar is expected to be upward; less rapid growth in consumption of ceramic feldspar is anticipated.

Jan 1, 1967

By R. Karl Zipf

The sudden, violent collapse of large areas of room-and-pillar mines poses a special hazard to miners and mine operators. This type of failure, termed a "Cascading Pillar Failure" (CPF), occurs when one pillar in a mine layout fails transfering its load to neighboring pillars causing them to fail, and so forth. Recent examples of this kind of failure in coal, metal and nonmetal mines in the U.S. are documented. Mining engineers can limit the danger posed by these failures through improved mine design practices. Whether failure occurs in a slow, nonviolent manner or in a rapid, violent manner is governed by the local mine stiffness stability criterion. This stability criterion is used as the basis for three design approaches to control cascading pillar failure in room-and-pillar mines, namely, the containment approach, the prevention approach, and the full extraction mining approach. These design approaches are illustrated with practical examples for coal mining.

Jan 1, 1996

By María del Rosario González Moradas

El presente texto describe diversas técnicas de teledección como métodos para determinar alguna de las variables utilizadas desde el punto de vista geotécnico y que permiten una clasificación de los macizos rocosos. La metodología se ha basado en la búsqueda de las bandas más ventajosas a las combinaciones más adecuadas para la determinación de cada una de las variables geotécnicas citadas a través de las imágenes landsat 5 de dos épocas diferentes.

May 1, 2017

By J B. Gemmell, D R. Cooke

Recent mapping at the Kelian epithermal gold deposit in East Kalimantan, Indonesia has delineated intrusive and extrusive-phreatomagmatic breccias, their magmatic roots, and late-stage endogenous domes of a maar-diatreme complex. The Kelian epithermal system is characterised by a wide variety of mineralised and unmineralised breccias, which include tectonic, hydrothermal, phreatic and phreatomagmatic varieties. Phreatomagmatic breccias and associated igneous rocks post-date early stage alteration and mineralisation, and pre-date main stage precious and base-metal mineralisation. This study emphasises the spatial, temporal and genetic links that have been drawn between diatremes and both epithermal and porphyry systems in volcano-plutonic arcs.

Jan 1, 1999

By P. R. Geoffoy, T. Koulomzine

"The discovery of the Mogador deposit concealed by 100 feet of overburden was the result of combined application of geological reasoning, ground geophysical surveys, studies of glacial float and extensive diamond drilling. The ground was acquired because it lay on the projected intersection of the Manville and Laflamme River faults. Systematic ground prospecting led to discovery of mineralized floats. A first unsuccessful exploration campaign lasted several years and consisted of 137 drill holes.In 1951 the boulder nests were reexamined and an associat'on of the mineralized float with boulders of a granodiorite, unknown in outcrops of the district, was established. Consequently, ground magnetic surveys were extended and re-interpreted, and a large anomaly interpreted as corresponding to a batholith was outlined. The existence of the batholith was immediately confirmed by drilling and the Mogador deposit discovered in third hole of new drilling programme in a zone of fractured volcanics paralleling southern contact of batholith.The Mogador deposit is a complex replacement of silicified volcanics by pyrite, pyrrhotite, sphalerite, chalcopyrite and galena carrying values in silver and gold. A total of 1,230,000 tons has been indicated, most of it now classified as fully developed proven ore."

Jan 1, 1960

Aluminum Production. -By October 1, Aluminum Company of America will restart a 35,000-ton-per-year unit at its aluminum smelter at Rockdale, Tex., restoring that facility to its full capacity of 325,000 tons annually. Primary Ingot Price Increase. -Most U.S. aluminum producers in mid-September were quoting a price of 72 cents per pound for primary aluminum ingot. On September 19, Kaiser Aluminum & Chemical Corp. announced that it would increase the price of primary aluminum ingot 4 cents to 76 cents per pound.

Jan 1, 1980

By B. P. Nutter, M. Lebourg, J. A. McAlister

The Multi-Flow Evaluator (MFE) is a new system of tools providing an original approach in drill-stem testing. It improves control during the testing operation and gives a more accurate evaluation of the fluid recovered while providing additional pressure information for reservoir analysis. The tools are operated entirely by up and down motion of the drill stem. This up and down operation provides a positive means of control and offers easily observed surface indications of tool operating position. An unlimited number of shut-in and flow periods may be taken with this tool while in the hole. The key to the success of the MFE system of tools is the safety seal packer. Until this development, operation of the tools by up and down motion only had proven unreliable. The success ratio of the MFE now exceeds the ratio achieved by conventional tools. The equipment includes a 2,750-cc chamber in which a representative sample of the flowing formation fluid is trapped at the end of the last flow period and brought to the surface under pressure. The sample can be evaluated at the wellsite or transferred under pressure for laboratory analysis. The sampling feature of the tool allows a sample to be obtained from a reservoir which has suffered minimum influence from production. A representative sample can be obtained for laboratory or empirical analysis by employing a testing technique to minimize drawdown during flow periods. Interpretation methods to take advantage of this additional information are presented and supported by actual field examples. INTRODUCTlON The Multi-Flow Evaluator (MFE) represents the most recent technical advance in formation testing. Drill-stem testing techniques prior to the MFE have been limited in three areas—(1) operaiion, (2) recovery analysis, and (3) reservoir analysis. The tools in the MFE system allow maximum control during testing and provide test information superior to that obtainable with conventional tools. The system of tools and the operation procedures are described to illustrate the mechanical advantages over present tools. Methods of pressure build-up and fluid

Jan 1, 1966

By George J. Young

DR . JOHN A . CHURCH, in his treatise on the Comstock Locle 1 gave a full and clear account of the conditions of the mine during the period of greatest activity. The difficulties in the way of deep mining at that time were excessive water and high temperature. The drainage of the mines taxed the financial resources of the mining companies, and the high temperatures restricted the capacity of the miners for underground labor. In spite of these difficulties exploratory work was continued until the financial burden of removing the water became too great. The companies then restricted the work to the upper levels. The years 1883 to 1886 marked the period of cessation of deep mining. For 12 years thereafter mining was confined to the levels above the Sutro tunnel; and, while the question of drainage was more or less agitated, nothing of importance was done until the formation of the Comstock Pumping Association in 1898. Since that time successive levels have been drained until, at present, on the north-end mines, a depth of 700 ft. below the Sutro-tunnel level has been reached. Mining is now carried on in the Ophir mine from the 1,700- to the 2,200-ft. levels, and a winze is being sunk to make connection with the 2,300-ft. level (the 2,450 ft. of the C. & C. shaft). In 1903-the Ward Shaft Association was formed to undertake the draining of the Central and Gold Hill group of mines, and at the present time a depth of 2,500 ft. has been reached in the Ward shaft. The situation at the Ward looks promis¬ing, and the 3,000-ft. level may be reached in the near future. It is proposed to establish a large pumping-station on this level, and then begin the opening of known ore-bodies and the prospecting for new ones. The main factors which have contributed to the successful solution of the drainage problem are the Sutro tunnel, the use of the hydraulic elevator as a sinking-pump, the concentration of pumping-units, and cheap electrical power. The question of high temperature and its control still remains as a minor but important problem. The temperatures encountered in the new workings are as great as those in the earlier periods. The Comstock was considered the hottest group of mines in the world, and I am not aware of similar conditions in any other mining-district. A water-temperature as high as 160° F. has been reported from the Ward shaft, and temperatures below the Sutro tunnel are very high in many instances.

Nov 1, 1909

By B. R. Mohal, S. Chander

"A new technique to determine wettability of powders is presented in this paper. In this technique the times for immersion of individual particles from air into liquids, defined as imbibition times, are measured. Through the measurements of imbibition times for a large number of particles, it is possible to determine homogeneity/heterogeneity of a powder sample with regard to its wetting behavior. Quartz particles give a very narrow distribution of imbibition times showing a homogeneous wetting surface whereas coal particles give a broad distribution indicative of the heterogeneous nature of its surface. The imbibition time measurement technique is considered to have certain advantages over other methods to determine wettability of powders in surfactant solutions. In this study we have also compared the imbibition times with the wetting rate mea¬surements obtained by a modified Walker test.INTRODUCTIONSeveral methods are available for determining wetting characteristics of sol¬ids. Each of the methods has been used in the past to obtain very valuable information for comparing wetting behavior of various solids in a given liquid or for comparing the wetting behavior of several liquids for a given solid. Each method measures a somewhat different aspect of wetting and therefore quantitative correlations between techniques have been difficult. A general approach is to use a method in which close similarity between the technique and the application (where results of wetting measurements are to be used) can be maintained. The objective of this investigation was to develop a method which could be used to determine the wetting characteristics of single particles in surfactant solutions. Wetting of individual particles is of importance in cap¬ture of dust particles by sprays of surfactant solutions.METHODS FOR DETERMINING WETTING — A BRIEF REVIEWThe various methods available for measuring wetting characteristics of solids include: contact angle, immersion/sink time, bubble pick-up, induction time, capillary rise, and displacement method measurements. Some of the methods are briefly reviewed in the paragraphs that follow."

Mar 1, 1989

By H. E. James

Much has been said and written about the need to reduce South Africa's dependence on gold. To compensate for the decline in the country's foreign-exchange earnings resulting from the phasing out of gold, which must inevitably occur at some future date, a far higher priority will have to be placed on the mining, beneficiation, and export of the 59 other mineral commodities produced in South Africa. The basic strategy of the mining and metallurgical industries should be to move from the traditional approach of establishing a resource base to the establishment of a market base; to turn from production orientation to market orientation; and to rely less on exploration and economies of scale and more on process innovation and product development. The enthusiasm, entrepreneurial spirit, and commitment of the leaders in the mining and metallurgical industry will clearly be of decisive importance in the establishment of new industries for the beneficiation and export of added-value mineral-based products. The State can make a significant contribution by the provision of a welldeveloped and efficient infrastructure, including rail and harbour facilities, communications and health services, roads, and of electricity and water supplies. In our search for a new development strategy for the beneficiation and export of South Africa's minerals, we need to recognize that no one nation has all the mineralresources that it needs. Commercial and strategic manipulation of mineral supplies should no longer be tolerated. The future of the human species lies in international cooperation and in a greater understanding of the limitations of the world we live in.

Jan 1, 1985

By Dennis Nottingham

Spin-fin pipe piles can develop large loads in tension, thus have evolved as a foundation product of great potential. Currently, over 500 spin-fin piles have been used successfully in dolphins, docks, buildings and bulkheads. Spin-fin piles are pipe piles with plates welded near the tip at a batter-in-screw fashion. Thus, as the pile is driven, the pile screws into position. Tests show this pile type to have highly unusual stress/strain relationships, wherein plunging failure is usually never reached either at normal or large deformations. Tension capacity can approach pile capacity in bearing; thus, large reserves are usually available for tension. Tests have been performed on 8-5/8-inch to 24-inch-diameter piles in silt, sand, and gravelly soil, to provide a broad spectrum of data.

Jan 1, 1990

Failure of rock materials is a process of crack propagation. Crack initiation takes place when the crack tip stress intensity K reaches a critical value called fracture toughness, K1C. The rock fracture toughness is known to be affected by the surrounding environment such as temperature, confining pressure and humidity. In order to examine the effect of humidity, a series of semi-circular bend tests were performed under various water vapour pressures in a rock material that is known to be anisotropic. Water vapour promotes stress corrosion of rock and therefore the fracture toughness was found to have a decreasing trend with increasing water vapour pressure. The rate of decreasing the fracture toughness depends on the microcrack density that promotes the migration of water vapour into the rock. Also in an anisotropic rock, the fracture toughness depends on the direction of crack in relation to the anisotropy of the rock material.

Dec 6, 2010

Lead Tariff.--The full House Ways and Means Committee approved H.R. 6089 which will have the effect of reducing the tariff on unwrought lead to 3% ad valorem, with a floor duty of 1.0625 cents per pound, compared with the currently effective rate of 3.5% ad valorem. Consideration is also being given to tariff rates on imports of red lead and litharge from Mexico. A consortium of domestic producers has appealed to the Office of the Special Trade Representative (STR) requesting a return to tariff schedules which were in effect prior to the concessions made effective on January 1. Mexican producers have filed a proposal in favor of lower duties, and the matter now awaits a ruling by the STR. Ferrous Scrap Exports.--After holding public hearings and receiving public comments in May, the Department of Commerce announced that it would not institute formal monitoring of ferrous scrap exports, as requested by the Ferrous Scrap Consumers Coalition. The Department said, however, that it would follow the trend of scrap exports and prices. Ferrous scrap prices are currently low and supplies are reported to be adequate.

Jan 1, 1980

The 1981 Review: In the late 1970s there was an upsurge of interest in the prospecting and mining of this countryÆs mineral resources. That upsurge of interest was accompanied by a mounting public concern over the damage mining operations might do to the environment. Concern was also expressed about what some people perceived as inadequacies in the legislation which regulates mining and the grant of mining privileges, and inconsistencies in the relationship of that legislation to other legislation regulating land use and the use of resources.

Jan 1, 1984

Antitrust Investigation Dropped. - The Department of Justice announced that it was dropping its 5-year investigation of the aluminum industry. The investigation was over whether the aluminum companies were acting as if they were a shared monopoly. Deep Seabed Mining. - The Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) has established an Office of Ocean Minerals and Energy which will be responsible for implementing the Deep Seabed Nard Minerals and Energy Act and the Ocean Thermal Energy Conversion Act. It will establish licensing and regulatory programs.

Jan 1, 1980

Workers at Anaconda Aluminum Company's primary aluminum smelter at Sebree, Ky., were back on the job December 1, after agreeing to a new 3-year contract. The old contract had expired November 15. On December 20, the Aluminum Company of America reportedly shut down a 42,000-ton-per-year potline at its Wenatchee, Wash., primary aluminum smelter and half of a 23,000-ton-per-year potline at its Vancouver, Wash., smelter as a result of a power cutback by the Bonneville Power Administration. A1 so in December, Kaiser Aluminum & Chemical Corp. reduced overall power at its Mead and Tacoma, Mash,, smelters and shut down one of eight 27,500-ton-per-year potlines at Mead. Reported shutdowns for the firms since September have amounted to 76,000 tons for Alcoa and 50,000 tons for Kaiser. Alcan Aluminum Ltd. announced plans to double the generating capacity at its Kemano hydroelectric power plant in British Columbia to 1,916 megawatts. The additional power would be equal to that required of a primary aluminum smelter with an annual capacity of 567,000 tons.

Jan 1, 1980