Search Documents

By Wilbert J. Huff

This is the sixth of a series of annual reports describing the work of the Explosives Division, Bureau of Mines, United States Department of the Interior.3/ It deals particularly with the activities of the division from July 1, 1940 to June 30, 1941. The studies outlined in this and preceding reports of the series have been conducted under the direction of the author and the respective unit leaders, to whom specific credit is given.

Jan 1, 1942

By Wilbert J. Huff

This is the sixth of a series of annual reports describing the work of the? Explosives Division, Bureau of Mines, United States Department of the Interior.3/ It deals particularly with the activities of the division from July 1, 1940, to June 30, 1941. The studies outlined in this and preceding reports of the series have been conducted under the direction of the author and the respective unit leaders, to whom specific credit is given.

Jan 1, 1942

By J. C. Martin

Stmplified equations are developed for the flow of fluids in gas drive reservoirs in which the effects of gravity can be neglected. The results show that the pressure distribution is governed by a nonlinear heat flow type of equation, and the saturation distributions are related to the pressure by the same equations QS those developed by Muskat for the average pressure and saturations in gas drive reservoirs. Unrler certain conditions the equation for the pressure can be approximated by the linear form of the heat flow equatlon. This equation tk analogous to the equation for the pressure in single-phase compressible flow The analysis reveals that the equation for the pressure in n~ultiphase flows can be obtained directly from the equation for the pressure in slngle-phase flows by simply replacing the single-phase compressibility by the total compressibility and the single-phase mobility by the sum of the mobilities of all the fluids present. Perrine's method of pressure buildup analysis for multiphme flows is based on these same substitutions. Thus, the development presented in this paper constitutes a theoretical justification for Perrine's method of pressure buildup analysis. One of the most difficult problems associated with the production of oil is the determination of the flow of the fluids within the reservoirs. One purpose of this paper is to present the development of simplified equations for the flow in gas drive reservoirs. The other purpose is to present some of the needed theoretical foundation for the methods currently being used in the analysis of multiphase pressure buildup data. The analysis presented in this paper makes use of a partial linearization of the equations governing multiphase flows. It is felt that the process of linearizing or partially linearizing the nonlinear equations of multiphase flows can lead to useful results since this process has proved extremely valuable in the study of other fields of science and engineering where nonlinear equations are encountered. Pressure buildup data of shut-in wells have been used for many years to estimate the static reservoir pressure. These data have also been used in studying the aver- age permeability both away from and close to the well-bores. The majority of the buildup data are obtained from wells producing two or three fluids. As yet the theoretical foundations for the methods of buildup analysis used in connection with rnultiphase buildup data have not been established. A number of methods of analysis of pressure buildup data have been developed." Most of these methods apply only to single-phase flows, and almost all of the theoretical analysis is confined to single-phase flows. Perrine' developed a method of analysis for rnultiphase flows from the method for single-phase flows of Miller, Dyes, and Hutchinson.' He did this by simply replacing the single-phase compressibility by the multiphase compressibility and replacing the single-phase mobility by the sum of the mobilities of the fluids in the rnultiphase flows. Obviously, such a procedure lacks a certain amount of theoretical justification, and such practices can lead to erroneous results. Fortunately, Perrine's results have a theoretical justification, and this justification is presented in the following discussion. It is assumed that gravitational effects and the cornpressibility of the rock can be neglected. Under these assumptions the equations governing the simultaneous flow of gas, oil and water in porous media areo* The preceding equations can be expanded into the following expressions.

By Masaki Imamura

A novel hydrometallurgical process for copper concentrate treatment has been developed by Niihama Research Laboratories of Sumitomo Metal Mining Co., Ltd. The process has numerous advantages with respect to the operational and environmental aspects. For example, copper is leached effectively from chalcopyrite concentrates by chlorine gas under atmospheric pressure. The copper in the leach solution is then separated from iron and silver by solvent extraction and undergoes electrowinning for its recovery as a highly pure copper metal; this does not require any further purification. Moreover, iron metal can be produced from the purified raffinate by electrowinning without generating a large volume of goethite or hematite, which are solid wastes generated due to iron rejection in common hydrometallurgical processes. This process can also realize the efficient recovery of precious metals. The results of batch testing and continuous-operation testing are presented in this paper.

Jan 1, 2006

By J. F. Havard

The enterprises based upon the industrial minerals are diversified in geologic habit, mining systems, processing techniques and marketing methods. Nevertheless, in 1972 these enterprises faced many of the same frustrations and hopes and knotty problems and crucial decisions. Volume and profits were generally improved but were uneven in extent and effect. The U.S. cement industry, for example, was unable to meet demand in major markets. It was constricted by a frozen low-level price structure, faced expensive pollution control measures and watched heavy imports penetrating its markets from several European nations, Mexico and Canada.

Jan 1, 1973

Maps To Accompany Bulletin 418

Jan 1, 1941

By J. Kulas, J. Weaver, K. Hagley

An assessment of potential groundwater movement beneath the tailing impoundment at the Red Dog Mine was performed, and has indicated a unique aquifer situation within sub-permafrost groundwater at the site. The aquifer was shown to be isolated from both vertical recharge and a real discharge, and is characterized as a virtually no-flow system. The permafrost resulted in a deep aquifer with high tidal efficiency, meaning that variable surface loads are easily transmitted to the fluid. The tidal efficiency has been characterized through analysis of water level fluctuations that respond to earth tides, barometric pressure loads, and loading from the pond.

Jan 1, 2002

By F. Hassani, R. Mikaeil, B. Ferdowsi

Two analytical solutions for estimating the ovaling deformation and forces in circular tunnels are widely used in engineering practice, due to soil-structure interaction under seismic loading. This paper discusses the discrepancy between the two analytical and finite difference methods. A comparison of the two analytical methods shows that the calculated forces and displacements are identical for the condition of full-slip between the tunnel lining and ground. However, the calculated lining thrusts differ by an order of magnitude when considering no-slip between the tunnel lining and the ground. The analytical solutions are compared to numerical analyses of the no-slip condition using the finite difference method to validate which of the two methods provide the correct method. To achieve the goal, numerical modelling, field data of the Kuhin railway tunnel and Manjil earthquake characteristics are used. Numerical analysis results agree with one of the analytical solutions that provides a higher estimate of the thrust on the tunnel lining, thus highlighting the limitation of the other analytical solution.

Jan 1, 2008

A variety of environmental financial assurance instruments are in use across the globe. This paper reviews some of the more common forms currently used in New Zealand, Canada, USA and Australia. In order to be effective, the form of assurance instrument selected needs to be aligned with a countryÆs specific environmental objectives, geography and political climates and also allow for a healthy investment climate. Industry and Government both have a strong interest in ensuring financial assurance criteria meet these objectives.   Recently Golder Associates have been involved in financial assurance assessments for various mining and quarrying companies across the South Island. Multiple stakeholders and regulatory agencies can make the setting of effective and fair financial assurance criteria a complex exercise for both regulatory agencies and industry.  The author relates experience gained in assessing financial assurance under current New Zealand legislation (RMA, 1991), effectively dealing with issues such as ôdouble bondingö and overviews potential approaches to dealing with transitional issues for historic and existing operating mine sites.

Jan 1, 2006

By S. J. Swart

This paper discusses the principles and application of risk assessment and management as the basis for environmental management within the mining industry. Unlike in other industries, mines are required to obtain closure certificates in terms of section12 of the Minerals Act, which should ultimately release them from further environmental responsibilities. It is emphasized that the concept of environmental risk assessment and management, when applied correctly will mean that the mine will be identifying and managing environmental issues beyond those set by current legal requirements and management strategies. The focus shifts from conventional minimum legal compliance management to management of real environmental risks. The advantage of this approach is that the perceived ?shifting of legal and management goal posts? due to changing environmental laws or management principles, will not influence or dictate the mine?s short or long-term management objectives or actions, mine closure funds can be more accurately determined and mine closure should become a relatively simple procedure. The risk assessment approach has been applied to the planning of mine closure at Iscor?s Durban Navigation Collieries (Durnacol) in Kwa-Zulu Natal and certain key risk issues such as the long-term risk of water pollution from coal discard dumps have already progressed to fully quantitative risk assessment. This paper will discuss the process, which has been followed to date, with particular emphasis on the most recent phase, namely quantitative risk assessment and management of pollution from coal discard dumps. It is believed that the approach that is being pioneered at Durnacol and which overcomes some of the more obvious deficiencies of both the EMPR and the traditional IEM process will ultimately serve as the model for all responsible mines in South Africa. It is also believed that this approach will enable the authorities to issue closure certificates with the confidence that there will be no unforeseen surprises in the years after closure.

Jan 1, 1998

By M. A. Trevits

Mine seals are used in underground coal mines throughout the United States to isolate abandoned mining areas from the active mine workings. The objective of adding inert gas to a sealed mine area is to quickly reduce the oxygen concentration in the sealed area to a level that will not support combustion. In the US, this process is typically conducted from the ground surface and because surface-to-mine access is constrained by so many variables, it is very difficult to provide a source of inert gas to the place where it is needed underground. To alleviate this problem On Site Gas Systems, under a NIOSH contract, built a nitrogen (N2) generation plant that operates in the underground environment. The purpose of this work was to create a reliable in-mine mobile plant that would extract N2 gas from the mine atmosphere and use the gas to create and maintain a safe sealed mine area. The plant is based on a novel design using pressure swing adsorption technology and is sized to fit on a standard shield car or mine dolly for easy transport in and around an underground coal mine. The plant is capable of producing about 900 scf/min of N2 gas at ambient mine conditions. After an exhaustive series of laboratory tests, the plant was field tested at the NIOSH Safety Research Coal Mine (SRCM) where a portion of the mine was sealed and rendered inert. During the test, the movement of the injected gas was monitored at several underground points to observe the progress and extent of the inerting process. This paper describes the plant design and the results of the field test at the SRCM. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of NIOSH.

Jan 1, 2009

By P. J. Lloyd

There are few data on the composition of discard coal in South Africa, and no overall view of the discards for the entire industry. As a result of work on coal qualities in South Africa, a database was established which enabled a good estimate to be made of the composition of the discard from every mine. The data are presented in the form of histograms of ash, volatile matter and fixed carbon content of the 43 million tons of material which were discarded in 1990. The results are discussed in terms of the closeness of the composition of much of the discard material to presently used power station coal. It is concluded that it is mainly developments in equipment, particularly fluidized bed boilers, which inhibit the wider use of discard coal. However, other factors must be noted, including the relatively high sulphur content of the discards, and the fact that even with the most careful storage the material ages and may become unusable after about 15 years.

Jan 1, 2000

By Paul R. Thomas

The Bureau of Mines evaluated the impact of the depletion allowance upon the economic availability of copper from domestic deposits. The potential long-run percentage depletion deduction, cumulated over the life of the properties, was estimated at approximately $2.5 billion for producing properties and up to $11.7 billion for nonproducers. The income transfer, in the form of higher Federal income tax payments if the allowance were repealed, was estimated at $1.5 billion for producing properties and up to $8 billion for nonproducers. The percentage depletion allowance, through its role in determining Federal income tax liability, was found to be very significant in affecting profitability. Repeal of the allowance could result in major domestic copper availability reductions at all price levels, now and in the future, as a result of reduced profit margins for current producers, and postponement of development decisions for nonproducers. It was demonstrated that a 50-percent reduction in the percentage depletion rate applicable to copper would also result in a significant decrease in profitability for nonproducing properties. For producing properties, the percentage depletion rate on copper was shown to be less significant than the income limitation that is placed upon the total amount of the depletion deduction. Repeal of the minimum Federal tax provision was shown to be significant in enhancing profitability for both producing and nonproducing deposits. The report concludes that the percentage depletion allowance operates as an important method of capital recovery and production incentive.

Jan 1, 1982

By L. R. Burdick, J. F. Barkley

"There is a general conceit in the coal trade that the moisture- and ash-free B.t.u. of coal from the same seam, and surely from the same mine,is substantially a constant; that calculation of the moisture- and ash-free B.t.u. value from the proximate analysis and B.t.u. determined in the laboratory will reveal whether a coal came from a given area or seam; and that, having this constant, the B.t.u. value of a coal sample can be calculated fairly closely upon a dry or as-received basis from the moisture and ash values of its proximate analysis.To illustrate with a simple example;"

Jun 1, 1941

By Stephen C. Tadolini, Raymond A. Mazzoni

The International Ground Control Conference in Mining has always provided an open forum for the publication, presentation, discussion, and often heated debate on roof bolting systems mostly with attention to how, when, and why they work. During the last 24 Conferences at least 170 papers have been presented by International Experts on these “simple” devices that range in length from 30-inches to 20 ft and from 5/8 to 2 inches in diameter. Roof bolts are primarily mechanically anchored, glued, cemented, or driven. Bolts are placed vertically, angled, or tied together with special fixtures (trusses and slings). They have been termed active, passive, stick-slip, and several other descriptive acronyms or mining slang expressions. This retrospective paper will present the changes in bolt types and usage, point out some of the biggest myths and hail the most significant advances (according to the authors’ opinions of course).

By M. D. Lionnet

The Bafokeng Rasimone Platinum Mine (BRPM) is a joint venture between Rustenburg Platinum Mines Limited and Royal Bafokeng Resources (Pty) Ltd (Bafokeng). The mining lease has been granted over Boschkoppie 104JQ and is located approximately 10 km south of the Pilanesberg Alkaline Complex. The Merensky Reef, which constitutes the principal orebody, is geologically complex. A relationship between its geological variability and the associated mineralization has been established by defining a number of facies types. The Merensky Reef has been subdivided into seven distinct facies types: the pegmatoidal facies, contact facies, FW1 potholefacies, FW3 pothole facies, FW6 pothole facies, and FW7 pothole facies. The Merensky Reef, which does not form part of the potholed reef, has a large component of footwall mineralization. The pothole facies, in contrast, has mineralization located in the hangingwall. Statistical analysis of the facies types indicates that they are unique populations and hence need to be evaluated independently. The mining lease has distinct structural domains that have added additional complications to evaluation of the Merensky Reef. The Merensky facies on BRPM exhibit unique geological and statistical characteristics within well-defined structural blocks. Due to the extreme variability of the Merensky Reef on BRPM a unique approach has been developed, within Anglo Platinum, to evaluate the deposit. Mining cuts are defined and composited for the individual facies types, and then modelled individually by applying known geological controls. The resultant grade models are weighted based on statistical and local geological knowledge. The object of weighting the facies is to replicate the variability observed in the orebody. The introduction of stringent geological controls to the evaluation process has resulted in increased confidence in the in situ grades estimated as an input to the mine planning process.

Jan 1, 2007

By J. P. BONARDI, C. W. Davis, R. B. Moore, J. W. MARDEN, S. C. Lind, J. E. Conley

The rare metals are becoming increasingly important to our industries. Rare-metal alloys have properties which indicate that we are only on the threshold of the possibilities of their utilization, not only in making nonferrous alloys, but also as special steels. Not only are their uses broadening rapidly, but the metals are affecting our industries in other ways. The oxides and some salts are used as pigments; others have medicinal value. The pure metals are made into filaments for incandescent lamps, and targets for X-ray tubes. By their efficient use in alloys, the weight of automobiles is reduced, • and the wear and tear on tires and roads is thus minimized; in machine shops they help to give greater efficiency to tools and reduce production costs. Their development has marked a milestone in the progress of civilization. There has been considerable uncertainty regarding analytical methods for the rare metals. A great deal has been published, but the weak and the strong points of the various methods have not been investigated as carefully as is needed. The Bureau of Mines at its Rare Metals station in Colorado necessarily had to do a great deal of analytical work in connection with the metals covered by this bulletin, which aims to give the results of the experience so acquired. No claim for much originality is made, although some published methods given have been modified, and some new ones have been developed by members of the staff. The principal methods available were studied critically, and it is to be hoped that the work will assist those interested in analytical work in connection with the metals named.

Jan 1, 1923

By A. R. Kiani-Rashid

In this paper, the effect of aluminum content on the formation mechanism, volume fraction, morphology and particle size distribution of graphite has been investigated. Addition of aluminum on ductile iron causes some fundamental changes in iron-carbon phase-diagram and as a result, improves the graphite formation during eutectic transformation. The results reveals that aluminum compounds have been formed in the core of graphite nodules, thus aluminum plays an important role in the formation of graphite nodules. Furthermore, it is indicated that an increase in the aluminum content also leads to an increase in the number of graphite nodules and a decrease in the nodules size. By using EPMA, the segregation of aluminum and silicon between graphite nodules has been studied

Jan 1, 2010

By R. P. Mohring

The South African Coal Industry had its beginnings in the Eastern Cape in 1859 when coal was mined to satisfy the fledgling settlements in the Eastern Cape. The growth in the industry was relatively slow up to the early 1970s when, firstly, the export business was expanded coupled with a major increase in the quantity of coal converted to liquid fuels and utilized for power generation. To meet this increased demand the industry developed many new operations employing the latest mining technology and systems. Coal production in South Africa reached 204 million tons in 1996 and revenue from exports reached R8 billion making it the second-largest foreign exchange earner after gold. In his address Rick P. Mohring describes the role coal plays in the international energy scene and outlines South Africa?s position as a producer and consumer of coal, and the challenges facing the industry. A wide range of steam-coals are produced to satisfy both the local market (power generation, coal conversion and the metallurgical industry) and the export steam-coal market. South Africa is in a unique position regarding the export market as it is still a relatively low-cost producer and is geographically well-placed to play in both the European and Far East markets. There are, however, a number of challenges facing the industry. To retain our competitiveness in the international market, ways of minimizing the cost pressures caused by high-cost inflation, increased environmental protection obligations and a decreasing quality resource base need to be sought. Locally the coal mining industry has a major role to play in Eskom?s goal of reducing the real cost of electricity by 15% in the next three years. Safety and health, productivity and the adaptation of the latest technology are issues being addressed by the industry to maintain its dominant position within the South African economy.

Jan 1, 1997

By P. Christmann

"In June or July 2005, the European Commission will present its Thematic Strategy on the Sustainable Use of Natural Resources proposal to the Council and European Parliament, one of the seven Thematic Strategies to be developed and implemented under the 6th European Environment Action Programme in support of the European Union’s Sustainable Development Strategy defined by the European Union’s Head of State at the Göteborg European Council, in June 2001. The time scale for this Thematic Strategy is 25 years (2005-2030). This paper discusses some of the key issues related to the EU minerals and metals industry that needs to be addressed by the Strategy. These are: - the need for access to mineral reserves in the EU and abroad; - the need to strenghten the capacity of developing countries to sustainably promote and regulate the use of their mineral potential; - the need for an EU mineral resources intelligence capacity. There are additional important needs, which are not discussed in this paper, such as: - the need to foster further innovation in mining, ore beneficiation and metallurgical technologies; - the need to integrate and simplify the exisitng complex regulatory framework applicable to the EU mining industry and to effectively implement existing legislation."

Jan 1, 2005