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By L. L. Hirst

In 1944, the 78th congress of the United States enacted Public Law 290, which directed the Secretary of the Interior, acting through the Bureau of Mines, to furnish industry with basic information and cost data for the development of a synthetic liquid fuels industry. Recently published information with respect to the cost of synthetic liquid fuels processes indicates a wide variation in estimated results. To clarify the results and inconsistencies for the hydrogenation of coal, the Bureau of Mines has prepared preliminary designs and calculated detailed investment costs from which the operating costs to produce 30,000 barrels per day of liquid products, mainly gasoline, by coal hydrogenation were obtained.

Jan 1, 1949

Minerals are fundamental to the U.S. economy, contributing to the real gross domestic product (GDP) at several levels?mining, processing and manufacturing finished products. The estimated growth rate for the real GDP of the United States was 2.1 percent and the nominal GDP was about $13.8 trillion in 2007 (Table 1). The prime interest rate decreased to 7.25 percent in December from 8.25 percent at the beginning of 2007, reflecting actions taken by the Federal Reserve Board to counter financial difficulties surrounding subprime mort-gages. Delinquencies on subprime mortgages increased throughout the year, affecting not only the delinquent home owners but also financial instruments invested in mortgage-backed securities. The average contract mortgage rate for the purchase of previously occupied homes in the United States was 6.35 percent in November; a slight decrease from 6.37 percent in January but still greater than 5.34 percent reported in July 2003, the lowest rate in the past five years. With the tightening of credit, the seasonally adjusted annualized rate for new privately owned housing starts declined 27 percent from December 2006 to November 2007. The loss in the residential market was balanced by a 9-percent increase in nonresidential construction between January and August 2007, during which slight increases occurred in nearly all

Jan 1, 2008

By L. E. Mordberg, E. N. Nesterova

Geochemical studies of the bauxite deposits show that the primary composition is gibbsitic. Some trace elements were relatively mobile during bauxite formation with the content of Th, U and Zr increasing and that of Rb, Ni and Co decreasing. Y and Pb were relatively immobile during lateritisation; their contents and ratios were inherited from different types of underlying rocks. The supply of Ni and Co took place at the diagenetic or epigenetic stages; their ultimate source was the crystalline basement in the region. The studies support the view that the bauxite was likely to have originated as a result of in-situ lateritisation and not through sedimentary transport and redeposition

Jun 18, 1905

General recognition of the potential benefits of utilizing advanced technology has focussed public attention on the organisation of tertiary education. This has produced a situation where opportunities exist for significant changes to be implemented. The challenges to Mining education in this environment of change are analysed with respect to the setting of education objectives, the role of centres of education, course structures and student access to courses. The scope of the analysis includes formal courses for professional education and technical training, and programmes for continuing education and postgraduate research. Previous significant advances in mining technology illustrate the importance of encouraging the establishment of an extensive involvement with mining education. Education cannot be the sole responsibility of professional academic organizations; significant industry participation is essential. Methods of achieving this interaction are discussed. Major changes in techniques available for disseminating information provide a significant incentive to assess the relevance of existing course structures and restrictions on student access to courses. Establishment of a less rigidly progressive system of education is discussed with respect to the development of the full potential of computer based learning. This will expand the availability of mining education to include remote locations. The practical feasibility of such changes and recognition of the value of education as a commercial resource could also increase overseas involvement in Australian mining education. Benefits of such changes and problems that may develop if accreditation systems are not also changed to take account of new technology are outlined.

Jan 1, 1989

By Sverre Olsen, Kai Tang

The composition of ferromanganese slag is very important as it determines the slag/metal equilibrium relations including MnO content of final slag, melting relations and slag viscosity. The slag composition is further expected to influence the process temperature. The properties of ferromanganese slags are suitably described by its basicity and A/S mass ratios. The influence of slag basicity has been discussed in the previous papers. The present paper will discuss the effect of Al2O3 on melting relations, viscosity and MnO-content of final slag. This discussion will be based on assessed thermochemical databases and a recently developed viscosity model.

Jan 1, 2007

By Steve Kral

Borates are minerals that contain boron. Trace amounts exist in rocks, soil, water and people. Boron-containing ores are rare and U.S. Borax, a subsidiary of Rio Tinto Borax, controls one of the world’s two world-class borate deposits. Through its global systems of mines, refineries, ports, sales offices and distribution centers, the company supplies nearly 45 percent of the world’s demand for borates. Borax has been mining borates in California for more than a century. This year the company celebrated 131 years of continuous business in the Golden State and 76 years at its operations in Boron, the site of California’s largest openpit mine. It also has mines and refineries in Argentina, refineries and ship-ping facilities in Europe and technical staff in the United States, North and South America, Europe and Asia Pacific. So, with the 130±years of borate mining and processing experience behind it as well as its global marketing and distribution centers, there is very little that Borax does not know about borates.

Jan 1, 2003

By F. S. Young

Previous laboratory and field experimentation has demonstrated the effect of several variables on drilling rate.1-5 These results have been incorporated into optimization theories6-" for the purpose of reducing drilling cost. Minimum-cost drilling theories rely on a combination of historical data and empirical prediction techniques for selecting optimum bit weight and rotary speed. Past solutions have required extensive use of computing equipment because of both the complexity of the mathematical formulations and the large number of parameters involved. Field attempts to apply these computed results have frequently failed because of the uncertainty of input data requirements. Humble has developed an on-site computer system to control bit weight and rotary speed and thereby implement the concepts of minimum-cost drilling. This system can (1) perform short interval drilling rate tests for formation evaluation, (2) use the results of these tests as input information to solve minimum-cost drilling formulas, and (3) control bit weight and rotary speed in accordance with these computed solutions. The purpose of this paper is to describe the computer control system and present results of initial field testing. Theoretical Considerations Minimum-cost drilling (MCD) requires a quantitative evaluation of the variables involved. Several forms of a basic mathematical model have been sug-gested.'?,' "he relationships reported here form the basis for the solution programmed in this work. Four equations are used, expressing drilling rate, bit bearing wear, bit tooth wear, and cost. A solution for minimum-cost drilling assuming constant bit weight and rotary speed over the entire bit life has been programmed for use in computing MCD schedules. This solution is subject to certain limiting assumptions such as those discussed by Graham et a1.I2: 1. Drilling cost is the summation of bit cost, rotating cost, connection cost and hoisting cost. 2. Diamond bits are excluded. 3. Bit life is limited by either bearing failure or tooth wear, or by a combination of operational factors that make it cheaper to pull an incompletely consumed bit. 4. Circulating hydraulics are adequate and do not limit drilling rate. 5. Bit weight considerations exclude hole deviation. 6. Drilling rate is a function of only bit weight, rotary speed, and degree of tooth dullness; that is, the effects of pressure, lithology, fluid properties hydraulics and drill string dynamics are ignored. In equation form, the four MCD expressions are as follows:

Jan 1, 1970

By J P. Ashby

Compared with elsewhere in the world, New Zealand quarries have tended to be mostly small. The reasons for this are a combination of the relatively high transport costs, low population density and a pioneering, self-employed attitude. The small size of the operations is reflected in low productivity, a tendency to repair and rebuild equipment rather than replace it, designed flexibility in the processing plant, minimal reserves investigation or development planning and a versatile and innovative work force who are generally not professionally trained. The Resource Management Act and the Health, Safety and Employment Act as well as a customer driven demand for higher quality and consistent products will have even greater influence upon future direction of the Industry. The trend will be towards fewer quarries operated by companies and professional managers that can adapt to the new demands.

Jan 1, 1993

By F. D. Richardson

STAFF: Editor, Gerhard Derge Carnegie lnstitute of Technology Schenley Park Pittsburgh, Pa. 15213 Editorial Assistant, M. A. Redmerski Production Editor, Otto T. Johnson THE METALLURGICAL SOCIETY: Jack H. Scoff, President; Richard C. Cole, Past-President; Harold 0. Emerick, President-Elect; Ralph L. Hennebach, Treasurer; Robert W. Shearman, Secretary; Donald A. Parks, Assistant Secretary; Leslie S. Wilcoxson, Assistant Secretary. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: R. E. Lund, Chairman; T. E. Dancy, H. O. Emerick, P. R. Gouwens, R. E. Grace, J. H. Jackson, H. H. Johnson, A. E. Lee, Jr., R. R. Nosh, R. D. Pehlke, and Paul Queneau. Review and selection of manuscripts is under the supervision of the following Publications Committees: Extroctive Metallurgy Division: R. E. Grace, Choirmon; G. M. Bell, D. W. Bridges, J. M. Cigon, G. W. Heoly, T. A. Henrie, R. D. (Holli-doy, C. E. O'Neill, C. S. Somis, A. W. Schlech-ten, and Charles Shull. Iron and Steel Division: R. D. Pehlke, Choirmon; T. P. Floridis, Arnulf Muon, G. R. St. Pierre, E. T. Turkdogan, L. H.Von Vlock, and J. M. Uys. lnstitute of Metals Division: H. H. Johnson, Jr., Chairman; J. B. Clark, Vice Choirmon; M. R. Achter, G. F. Bolling. J. O. Brittoin, G. P. Conard, II, R. S. Davis, L. A. Girifolco, G. T. Hohn, J. P. Hirth, L. Himmel, G.T.horn, George Krauss, J. D. Livingston, R. D. Manning, H. M. Otte, S. V. Rodcliffe, R. E. Reed-Hill, H. C. Rogers, E. ScaIa, O. Sherby, M. T. Simnad, G. R. Speich, E. A. Steigerwald, R. A. Swolin, W. A. Tiller, W. R. Upthegrove, J. B. Wagner, Jr., Derek Wolton, H. W. Weart, W. W. Webb, and D. Published seven times yearly in February, March, April, June, August, October, and December by the American lnstitute of Mining, Metallurgical, and Petroleum Engineers, Inc., 345 East 47th Street New York, N. Y. 10017. Telephone PLAZA 2 -6800. Subscription $30 per year for non-AtME members m United States and North, South, and Central America; $32, foreign; $7.50 for AlME members Single copies, $6.00, single copier foreign, $6.50. The AiME is not responsible for any statement made or opinion expressed in its publications . . . Copyright 1964 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . . . Registered cable address, AiME New York Indexed in Engineering Index, Industrial Arts Index, and Chemical Abstracts. Second dost postaas poid ot New York, N. Y.,ond Ann Arbor, Mich. Volume 230, Number 6.

Jan 1, 1964

By Eric Low

Raising capital by issuing debt or equity is necessary in almost every corporation. In the field of corporate finance, the raising of capital is a heavily-studied topic. However, some of what is studied on this topic in corporate finance is not applicable in the mining industry. There are also many financing options that were created for the mining industry such as flow-through shares, prepaid forwards, and royalty sales. The cyclical nature of the industry makes the risk-return profile of financings more difficult to estimate than in other industries. Additionally, the methods used to assess firm value are different than other industries, as the values of orebodies are not included on balance sheets. For precious metals companies, which are a hedge against most other securities, there are additional complications with determining investor expectations and cost of equity. This thesis puts forth a decision-making framework to explain mine financing choices from the perspective of mining companies. The approach is threefold. First, all of the major equity and debt financing instruments available to mining companies are presented and analyzed. Each financing method is assessed on a wide range of criteria. Next, these concepts are applied in case studies of four companies: BHP Billiton, Barrick Gold, Teck Resources, and Noront Resources. For each company, the overall choice of financing methods is shown and analyzed. The effect of financing choices on the weighted average cost of capital (WACC) is calculated. The final section deals with case studies of individual mine finance decisions during the past two years.

May 1, 2011

By K. H. Coats, M. H. Terhune

Analysis and example applications have been performed to compare the accuracy and computing speed of alternating-direction explicit and implicit procedures (ADEP and ADIP) in numerical solution of reservoir fluid flow problems. ADIP yields significantly greater accuracy and requires about 60 per cent more computing time than ADEP, not 300 or 500 per cent more as reported elsewhere. l,2 INTRODUCTION Several recent papers 1-3 discuss an alternating-direction explicit difference approximation (ADEP) to the diffusion equation. Example applications of ADEP and ADIP4 were reported to support conclusions that ADEP is comparable in accuracy to ADIP and requires one-fifth to one-third the computing time of ADIP. Applications of ADEP in calculation of two-phase flow in reservoirs was also proposed. 3 This study was performed to compare further the relative merits of ADEP and ADIP in simulation of two-dimensional flow of one and two fluid phases in reservoirs. Since two-phase flow equations are often essentially elliptic rather than parabolic, the efficiency of ADEP in solving the elliptic equation was also examined.

Jan 1, 1967

?Classification System Efficiency (CSE)? is a simple, powerful concept which can be used to measure and improve ball mill circuit efficiency. This paper describes six plant case studies which demonstrate the use of CSE to diagnose and/or improve grinding circuit performance, with related improvements in circuit efficiency ranging from 3 to 30 percent. The increased effective mill grinding energy is recaptured from energy that was going into over grinding, which can greatly benefit downstream mineral separation. The achievable CSE for given circuit design/operating variables is described, providing every plant metallurgist with the means to determine the potential for increasing their particular grinding circuit?s efficiency through increased CSE.

Jan 1, 2012

By William H. Highlands

Lightning is a natural phenomenon which poses a potential hazard to people, structures, and equipment unless adequate protection is provided. The type of protection required is related to the nature and of the facility. The decision making process involves a number of interrelated factors which should be considered when determining the need for protection.

Jan 1, 1989

By K. Hanson

When done properly, benchmarking is an extremely effective tool for assessing ones performance, finding areas for improvement, and identifying strengths. However, when done improperly it can be an exercise in futility and result in incorrect observations and conclusions. A primary pitfall of benchmarking is collecting too much unreliable information. Surprisingly, the evolution of data storage and the ease of data collection are not helping with better data collection. Instead, it is just allowing one to collect more information, while at the same time inundating one with too much data. Additionally, the process of data collection can be tedious and is often times delegated to the least experienced individual resulting in unreliable and incorrect data collection and entry. Another primary pitfall of benchmarking is metrics that are cost based or poorly designed. Cost based metrics typically involve comparing unit mining costs ($/tonne). Between mines, unit mining costs are not very well correlated and have become further complicated by significant regional cost variations and mining inflation in the last years. Likewise, poorly designed metrics lead to poor benchmarking results. Examples of poorly defined metrics include: metrics that rely on information that is difficult to collect, metrics that are poorly defined, metrics which are too site focused, and metrics that measure low consequence practices.

Jan 1, 2011

By Robert B. Worthington

This investigation was undertaken to develop a more efficient copper smelting practice that would help meet the increasingly stringent antipollution standards. Continuous smelting to copper and a 0.8-to 5-percent copper slag using pure oxygen has been demonstrated for several hours at a time in a unique double furnace, which was devised to overcome the heat losses inherent in a laboratory furnace. The use of pure oxygen to effect the smelting and conversion of copper sulfide concentrate in a single unit to produce blister copper and a very high S02 concentration provides a much reduced gas volume for more economical and thorough sulfur recovery. Although the process was successfully demonstrated for several hours at a time, extended test work using longer runs will be required to balance the system and to obtain test data for adequately demonstrating its technical feasibility.

Jan 1, 1973

By Thomas C. Anderson

Tiedback walls are now recognized and accepted as a good solution for a variety of structural problems: ? Retaining Walls and Bridge Abutments in cut situations ? Landslide stabilization ? Repair/support of existing walls Acceptable techniques have been developed for anchoring in cohesive and granular soils and in any kind of rock. Methods have been developed for adequately protecting tieback tendons against corrosion and for testing every tieback to verify its long-term load-carrying capacity. However, the major problem that the industry faces today is how do we get constructable and economical tiedback walls contracted for and built with minimal claims. This paper will explore the issue of "constructability" through a look at specific problems from actual projects. From a research report from the Construction Industry Institute, Austin, Texas (1986), constructability is defined "as the optimum use of construction knowledge and experience in planning, design, procurement and field/operations to achieve overall project objectives." Maximum benefits occur when people with construction knowledge and experience become involved at the very beginning of the project." The design and installation of tiebacks has been developed primarily by specialty contractors; each contractor has evolved its own methods of performing the work, and consequently, many of the techniques are patented and proprietary. The real question is, how do we make effective use of this knowledge and experience during the design phase of the project?

Jan 1, 1991

By R. Loots

High temperature creep resistant alloys are used in power plants as steam pipes and headers where they have to withstand super heated steam temperatures of up to 600ºC for the lifetime of the plant. Frequently certain portions of pipes may be subjected to excessive temperatures and consequently suffer from creep damage. Damaged portions then have to be replaced by welding new steel to the service exposed steel. Such welds will have to be subjected to a post weld heat treatment (PWHT) to relieve residual stress. During such a PWHT it is then possible for the steel to crack in the heat affected zone (HAZ) by what is known as Reheat Cracking (RHC), also known as stress relief cracking. For the present purpose the RHC susceptibility of service exposed steel was compared with that of new steel by reproducing the temperature cycle to which the HAZ will be subjected during welding in a weld simulator. This was followed by PWHT where the influence of residual stress was studied by applying a constant stress to such a weld-simulated specimen in a creep testing machine. A sharp spiral was machined along the length of the cylindrical specimen to simulate the presence of a possible weld defect. In this way it is possible to subject all portions of the simulated HAZ to the same stress intensity. For the purpose of the investigation 1/2Cr-1/2Mo-1/4V steel known to be susceptible to RHC was chosen. During testing a constant tensile stress was maintained while the temperature was increased to follow the thermal cycle prescribed for PWHT. It was found that the new steel in all instances failed by RHC along the grain boundaries in the high temperature heat affected zone. In the case of the service exposed steel the creep strength of parent metal was lower than that of new steel as a result of exposure to a steam temperature of 540°C for about 15 years. Consequently, all of the failures during testing occurred in a ductile manner by necking outside the HAZ rather than by RHC. When service exposed steel is welded to new material, it is expected that the creep strain associated with stress relaxation will mostly be concentrated in the parent steel outside the HAZ. Accordingly, it should probably not be necessary to make any extra allowance for reheat cracking during repair of steam pipes manufactured from 1/2Cr-1/2Mo-1/4V steel other than that applicable for welding new steel.

Jan 1, 2004

By Tony Peglas, Harry Asche, Eva Wood

The North-South Bypass Tunnel is a new $AUD1.5 billion underground traffic route in Queensland, Australia, a project of the Brisbane City Council. The tunnel is approximately 5.2 km long, bypassing the Central Business District, and is adjacent to and below major buildings and services. Road tunnel alignment issues include the complex southern connections to the Pacific Motorway and the design of ramps to the east and the north. A review of road tunnel alignment criteria and accident data for Australian and overseas tunnels, similar to the proposed NSBT, are discussed. The key findings of this review lead to a rationalization of the traditional tunnel cross sectional width allocation. The road alignment design elements adopted for the NSBT are also discussed. The NSBT route crosses beneath the Brisbane River. Geotechnical investigations and hydrogeological modelling are described. The crossing has a fundamental impact on the alignment and the tunnelling methods. The tunnelling methods to be adopted and the tunnel support are described. The geotechnical investigations and hydrogeology analysis culminate in the selection of a single shielded TBM for the reference design. These outcomes are related to complex issues of hydrogeology and contaminated groundwater. These are discussed in detail.

Jan 1, 2005

By B. Asbury, M. Cigla, C. Balci

The Western Mining Resource Center (WMRC) at the Colorado School of Mines (CSM) received a grant from the National Institute for Occupational Safety and Health (NIOSH) to perform a study that will help reduce the amount of respirable dust generated from the cutting of coal. The study is based upon laboratory testing and field experience. This information is being used to develop a new cutterhead design in conjunction with Joy Mining Machinery. The new cutterhead design is being evaluated with existing computer models developed at CSM. The new continuous miner cutterhead will be tested at the Twenty Mile Coal Company’s Foidal Creek Mine. Baseline testing with the current cutterhead will also be performed. This paper presents laboratory test results, design methodology, and test results performed to date.

Jan 1, 2002

By Thomas O. Glover

Cameroon's mineral industry continued to be dominated by crude petroleum. The country's economic development depended on the production and export of crude oil. Oil output was estimated to be 56 million barrels in 1984 compared with 47 million barrels in 1983 and 39 million barrels in 1982. The country's only refinery processed approximately 16,000 barrels per day of crude oil in 1984, operating at slightly over 50% capacity. This volume, however, supplied the domestic need for motor fuel and heating oils. Cameroon's economy continued to expand despite problems and setbacks stemming from the attempted coup of April 6, 1984. Gross domestic product (GDP) growth in 1984 was 6.5%, the same rate as in 1983. Offshore crude petroleum production was the chief factor in the sustained economic growth. The country also maintained a relatively strong balance-of-payments position through oil exports. Investment, ranging up to 25% of the GDP, greatly contributed to sustained growth. The oil sector contributed approximately 14% to Cameroon's GDP in both 1983 and 1984.

Jan 1, 1986