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Many USBM research and information products are available through the systems or formats listed below: Mines FaxBack: Return fax service. 1. Use the touch-tone handset attached to your fax machine's telephone jack. (ISDN [digital] telephones cannot be used with fax machines.) 2. Dial 202/219-3644 3. Listen to the menu options and punch in the number of your selection, using the touch-tone telephone 4. After completing your selection, press the start button on your fax machine. Mines Data: Computer bulletin board. Log on via modem through 202/501-0373, or call 202/501-0406 for technical assistance. CD-ROM: This USBM disk is updated quarterly and sold by GPO's Superintendent of Documents. For information on the latest product, please contact Rodger Wedgeworth, 202/501-9557. Internet/World Wide Web: Text and graphics. Access via PC-based browsing software such as Netscape or Mosaic. Universal Resource Locator (URL) is: http:/www.usbm.gav Internet/Gopher Server: Text and tables only. Using Gopher client software, access via port 70 as follows: gopher.usbm.gav Internet System Administrator: webmaster®usbm.gov (or contact your local System Administrator).

Jan 1, 1995

By I. L. Whyte

apparent density and drag coefficient of porous ores on

Apr 1, 1995

By N. Kornelius

In recent years there has been an increased focus on corporate governance matters worldwide. The duties and responsibilities of directors of companies have come under close scrutiny, with shareholders increasing their demands for greater responsibility and accountability. Media attention and pressure groups have also had their effect. Governmental actions have supported these demands and directors have witnessed sweeping legislative changes imposing more onerous duties and liabilities than formerly imposed upon them at common law and in terms of the Companies Act. At the same time, the power of regulatory bodies has been increased to enforce this legislation and make someone pay to remedy an alleged infringement. Breach of such duties may incur personal or criminal liability, or both. Environmental protection legislation has become a particularly prevalent feature in this regard, and the number and complexity of statutes concerning the environment have increased over the past few years. Directors of South African companies will be familiar with relevant acts such as the National Environmental Management Act 107 of 1998; Conservation of Agricultural Resources Act 43 of 1983;Hazardous Substances Act 15 of 1973, as well as the National Water Act 36 of 1998. Now the directors of mining companies are faced with the Mineral and Petroleum Resources Development Act 28 of 2002.

Jan 1, 2003

By Merle L. Bowser

An alinement (steering) sensor for continuous mining machines has been developed under a Bureau of Mines contract. A laser source in the entry projects a beam parallel to the centerline of the entry. The beam is optically shaped to a narrow, vertical fan and illuminates an array of optical sensors bunted on the mini machine. These sensors interpret the location of the beam into meter readings of heading (angle) error and lateral displacement errors. The system, which was tested for 5 months in an operating mine, appears to be fundamentally sound, and with some modification, should be applicable to remote or automatic guidance of continuous miners and other machines.

Jan 1, 1976

By J. W. Neale

Mintek and BacTech have joined forces to provide the metallurgical industry with bacterial-oxidation processes for the treatment of sulphide ores. The processes are aimed at both refractory gold-bearing and base-metal concentrates. Previously, BacTech had commercially implemented the refractory gold process at the Youanmi Gold Mine in Western Australia. More recently, the process has been incorporated in the Sulphide Treatment Plant at the Beaconsfield Gold Mine in Tasmania, Australia. In addition, Mintek and BacTech have recently signed an agreement with the Laizhou Gold Metallurgy Plant in China?s Shandong Province, which will see the third commercial realization of the technology for refractory gold. Development of the base-metal technology is the subject of several papers in the proceedings of this colloquium. The implementation of the refractory gold technology at Beaconsfield is discussed in detail. Some important aspects that are covered include: ?Test work, and the choice of bacterial culture ?Process design choices, and the advantages of the Mintek-BacTech process ?Inoculum build-up ?Plant commissioning ?Plant performance. Besides the Laizhou project, Mintek and BacTech are currently investigating several other commercial prospects for the technology. These include the use of the technology for a gold-copper deposit, where the production of both gold and copper is envisaged.

Jan 1, 2000

By Kate Satish

M/s Konkan Railways Corporation are constructing 760 kms long rail road in the Western Coastal Region of India. The rail road encounters 75 tunnels through the Western Ghats of India with a total length of 78.35 kms, the longest tunnel being 6.5 kms long. The tunnels are of horse shoes shape having a cross section of about 37 Sq.meters

Jan 1, 1996

By B C. Sarkar, D Ray, V Sarkar, P K. Sinha, R K. Singh, A Kumar

Estimation of iron ore grade distribution has been attempted using geostatistics and artificial neural network (ANN) based models for a banded iron formation (BIF) type iron ore deposit of East India. Geologically, it is a supergene iron ore formation through an enrichment process of parent material (BIFs) by gradual leaching of impurities, namely SiO2 and Al2O3. As the degree of leaching differs spatially, distribution of Fe varies depending on local controls of ore formation. While geostatistical methods work on models based on spatial correlations of mineralisation parameters, ANN models a non-linear distribution and is widely used as a global approximator. Spatial distribution modelling of Fe values has been carried out employing ordinary kriging (OK) and sequential Gaussian simulation (SGS). Non-linear modelling has been performed using hybrid neural networks (HNN) that provided an alternative option for grade estimation. Classical statistical modelling revealed a negatively skewed 3-parameter lognormal Fe population having a mean of 60.49 per cent with a skewness of -0.08 and a kurtosis of 2.60. Semi-variography and geostatistical estimation employing OK procedure led to block-by-block kriged estimates with associated kriging variance, which provided an overall mean kriged estimate and kriging variance of Fe as 60.29 per cent and 7.76 (per cent)2 respectively. SGS procedure revealed a mean of 60.71 per cent and a standard deviation of 5.89 per cent with minimum and maximum values as 45.12 per cent and 68.70 per cent respectively in respect of Fe. HNN model provided values of mean squared error (MSE) and correlation coefficient (R2) as 12.33 and 0.61 respectively, thereby exhibiting the robustness of the model to sustain maximum heterogeneity within the target domain. A comparison of Fe grade estimates obtained by kriging, simulation and HNN models more or less maintain similar distribution patterns that are close to the sample data. It is thus opined to carry out the grade prediction exercise employing all these three modelling approaches to obtain alternative scenarios for improved mine planning and design exercises. The techniques provide a foundation for cogent grade modelling leading to improved iron ore reserve estimation procedures.CITATION:Sarkar, B C, Singh, R K, Ray, D, Kumar, A, Sinha, P K and Sarkar, V, 2017. Iron ore grade modelling using geostatistics and artificial neural networks, in Proceedings Iron Ore 2017, pp 431–438 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

The introduction of computer technology to the mining industry has produced many benefits for the mining engineer. The most significant is the dramatic increase in productivity realized by the individual user. This is important during times of competitive market conditions. Software for the minerals and energy industries has evolved substantially over the past decade. But even today it remains difficult to find a system that features the flexibility and integration capabilities to effectively (and cost-effectively) handle the needs of professionals in each phase of the mining industry - from exploration to reclamation. Several national software developers are now addressing this challenge. One Denver-based company, MINEsoft Ltd., offers a software package that is currently being used in each phase of the mining industry. The basic technology used in MINEsoft's database management system was developed in the 1960s. But during these early years of the computer industry, most of the technology was available only on mainframe computers, and then only as separate entities. MINEsoft's system unifies these various systems in one package that can be used on most computers manufactured today. Database Management System TECHBASE is a flexible, integrated database management system designed specifically for technical applications. The system features a database manager with no practical limit to the amount of data it can store, retrieve, and manipulate, according to the company. TECHBASE in¬cludes Applications Packages (TAPs) designed to meet the needs of professionals in a host of industries. Clients use the TECH BASE system to prepare many reports, including important EPA information. The package reduces data to a manageable level and enables users to increase productivity with a smaller staff. Mining engineers no longer need to do things by hand. What used to be a day's work can be accomplished in an hour or two. Exploration "Using the TECHBASE system to generate maps has probably saved us the expense of three or four draftsmen," says Ralph Fitch, regional manager and senior staff geologist with Chevron Resources in Portland, ME. "The system has great flexibility. You can treat it much like a spreadsheet. If you are halfway through with a particular project, the system allows you to add fields and calculations with ease but without starting over." Fitch uses TECHBASE for the "straightforward" plotting of results and generation of geochemical and geophysical profiles. "In exploration," he says, "these are the two key elements ... the generation of maps and data profiles. The system allows you to plot as many elements and variables in these areas that you like." Other aspects are important, too, says Fitch, including drill hole sections. "We use all the basic capabilities the system provides in the complete package," he explains. "When shopping for a system, TECHBASE was clearly dedicated to exploration in the

Jan 9, 1987

By Francis E. Federspiel

A mineral purvey of the Granite Chief RARE II area (A5-261), covering about 23,400 acres (9,470 ha) of Tahoe National Forest and the Like Tahoe Management Unit, was conducted by the U.S. Bureau of Mines and the U.S. Geological Survey in 1979 and 1980 (fig. 1). The investigation by the Bureau of Mines indicates that the area has a low potential for mineral resources. Samples taken from prospect pits and favorable outcrops indicate no minable quantities of precious or base metals. Placer deposits are too small and low grade to be considered a resource.

Jan 1, 1981

By E. D. Wilson

A study of factors related to subsidence was specified in a project proposal entitled "Structural Analysis of Block-Caving Operation, San Manuel Copper Mine, Pinal County, Ariz.," approved by the Bureau of Mines early in 1953. This proposal was designed by Charles H. Johnson, then chief of the Base Metals Branch of the Minerals Division, Washington, D. C., assisted by Dr. Leonard Obert, chief of the Applied Physics Branch, Region VIII (now Region V), College Park, Md., and E. D. Gardner, chief mining engineer, Bureau of Mines, Washington, D. C. It read as follows: This project is a study of the mechanics of undercut block caving in a deep ore deposit. The San Manuel is a low-grade disseminated copper deposit containing nearly a half billion tons of ore lying at depths of 500 to 2,000 feet. Development is just starting. Production is to begin in 3 to 4 years (in 1956) at a rate of 30,000 tons of ore a day, or 60,000 tons of copper a year. A Government loan of $90,000,000 /subsequently increased to $94,000,000/ and a long-term Government purchase contract support the capital investment, which will total about $110,000,000.

Jan 1, 1957

By Tim Hurley

On Friday, May 27, 1983 at about 6 p.m., an avalanche occurred at the Revenue-Virginius Mine. Six mine personnel and two contract diamond drillers were trapped when the avalanche covered and blocked the portal, the only access into the mine. The San Juan Mountain Range in southwestern Colorado is an old volcanic caldera. It has dikes and other intrusions, many of which are mineralized with sulfide ores rich in silver, gold, lead, zinc and copper. Several peaks rise above 4,260 m (14,000 ft) and the district has been the location of avalanches dating back to prehistoric times. This is evidenced by the numerous snow-slide chutes that are infamous enough to be named on topographic maps.

Jan 1, 2006

By H. Nan

Using the case of Qianqiu Mine, Yima Coal Mining Administration, theoretical analysis, laboratory physical simulation, and underground observation were performed to study the major parameters for fully mechanized sublevel caving mining method, including drawing spacing, drawing sequence, drawing numbers, and number of shields performing simultaneous drawing. The effects of those parameters on coal recovery and amount of waste rocks were also investigated. The optimal coal drawing technology for this case was obtained.

Jan 1, 2006

By H. E. Biber

DURING the production of tin plate a thin layer of FeSn2, is formed at the interface between the steel sheet and the protective tin coating. Because excessive amounts of this alloy layer are undesirable, the kinetics of its formation is a subject of interest in the tin-plate industry. A recent study of this subject at our laboratory uncovered a relationship which should be of general interest to anyone studying kinetics of reactions in metallic systems. It had been previously concluded that, at any given temperature in the range 175" to 330°C, the Fe-Sn alloy layer would have a parabolic growth rate.1,2 However, our studies showed that this rule apparently holds only when the tin plate is heated very slowly to the "reaction" temperature; when the tin plate is rapidly heated, considerably different growth rates occur. An example of this effect of heating rate on growth behavior is contained in the accompanying results of alloy-layer growth measurements at 240°C in oil baths stirred at 10,500, 1800, and 0 rpm. The heating curves for these three conditions are given in Fig. 1, and the growth data are presented in Fig. 2. With the rapid heating rate, provided by the stirring at 10,500 rpm, the alloy layer had three distinct stages of growth. In the initial stage, which persisted well beyond the time required to heat the tin plate to bath temperature, the alloy layer formed very rapidly. The growth followed a rate law of the form w = ktn where n > 1. This initial stage was followed by a growth-retardation stage of about 50-sec duration in which little additional alloy was formed. In the third stage the growth again followed a rate law of the form w = ktn, but here « =0.3. With the intermediate heating rate provided by stirring at 1800 rpm, the three-stage nature was less pronounced and the slope of the third stage increased (i.e., n > 0.3). With the slow heating rate provided by the unstirred oil bath, the alloy layer grew in two stages. The initial rapid-growth stage persisted only until the specimen was heated to bath temperature, no growth retardation was observed, and the slope of the main portion of the plotted data was greater than in the stirred baths, having a value of almost 0.5. Similar results were obtained for other bath temperatures in the range 200" to 300°C. This effect of heating rate on growth behavior may be due to changes in the rate of nucleation of FeSn, crystallites. The iron and tin are in contact from the onset of heating. Thus the initial formation of FeSn, occurs not at the "reaction" temperature but rather while the tin plate is being heated to that temperature. Because nucleation is in general temperature-dependent, different heating rates could cause different over-all nucleation rates, which in turn could cause different growth behaviors. A more detailed discussion of the growth of Fe-Sn alloy layer and the effect of heating rate will be published shortly.

Jan 1, 1965

By L Lorenzen

In this paper, we developed and implemented a fuzzy logic expert system capable of evaluating the degree of sustainability within the context of gold mining operations. The newly introduced approach of evaluating sustainability in the gold mining industry has the merit of sufficiently handling diverse, sustainable, development-related qualitative and quantitative data owing to fuzzy logic technology capabilities in dealing with linguistic syntax. The economic, environmental and social indicator inputs were independently evaluated and then combined with the aid of fuzzy logic to provide an overall sustainability index on a scale of zero to one. A total of 66 independent indicators were identified and applied in our model. The novelty of this work lies in providing a coherent numerical and automated approach in evaluating sustainability in the context of gold mining operations. In addition, the model can aid policy- and decision-makers in arriving at consistent decisions regarding the degree of sustainability on various aspects of gold mining operations. The functionality of this model will be illustrated through several examples.

Jan 1, 2007

By D. Pillay

Outsourcing? and ?sub-contracting? have become buzzwords in recent years, as SA industry becomes increasingly exposed to the global economy, and global competitiveness. In its effort to ?catch up? after years of relative isolation, there is a concerted effort to learn from global ?best practice?, in order for South African companies, and the SA economy, to become ?winners?. There seems nothing wrong with this approach at face value. Companies need to compete and be profitable if they are to remain in business. Failure will in the end mean bankruptcy, and the loss of jobs. However, if one interrogates the precise practices, and their implications for all concerned?not just shareholders and employers, but workers, communities, the environment, future generations, the national economy?then the picture can change dramatically. ?Best practice? for whom?

Jan 1, 1999

By L. K. Bandyopadhyay

The expert system component of Knowledge Base System supports the analysis and interpretation phases of ventilation design with an algorithmic program used for the solution of alternate design. The paper describes the ?ES-VENT? knowledge based system developed at Central Mining Research Institute, Dhanbad, India for an on-line diagnosing of the ventilation problems using the ?IITMRULE? expert system development tool. In the ?IITMRULE? expert system tool, it has been decided to use a backward chaining reasoning process to reach the goal state i.e. the final conclusion. ES-VENT system is made of three modules: On-line Data, Diagnostics and KBS. Each module is being a collection of several programs. The paper mainly deals with the parameters affecting the ventilation of underground mines such as air-velocity, air pressure, temperature, dust, and humidity and gas contents. The graphical presentation of these parameters on the computer and the interactive part of the developed program is expected to help a ventilation officer to determine the changes in a ventilation circuit necessary to bring the mine ventilation to the desired value. Once such changes are physically effected, the display will indicate if the changes have brought the desired effect or not on ventilation. Keywords: Ventilation network, on-line data, expert system, intelligent system, knowledge base, inference engine.

Jan 1, 2002

The Golden Cross mine commenced production in December 1991. Both open pit and underground mines produce 1000 tonnes of ore per day. Mining techniques are discussed along with results and variations to proposed methods of extracting the ore.

Jan 1, 1992

By William O. Vanderburg

This paper gives the results of a reconnaissance of the mining districts in Pershing County, Nev., made from March 9 to April 1, 1936. During the field work nearly all of the mining districts in the county were visited, and considerable data were obtained on active and inactive properties. The report covers the location of the various mining districts, nature of the deposits, information on past

Jan 1, 1936

By T. O. Allen, J. H. Atterbury

Laboratory and field tests during the past five years indicated considerable variation in the penetrating power of commercially available gun perforators. Many of the guns which achieved inadequate penetration in these tests have since been improved. However, recent productivity tests indicated the possibility of inadequate penetration or, at least, ineffective penetration in some wells. Laboratory experiments under simulated well conditions have demonstrated considerable plugging of the perforations, apparently as a result of factors associated with the shooting process and/or the drilling mud in the well at the time of perforating. The restrictions to flow per unit of hole depth caused by this plugging appears to be greater for jet perforators than for bullet guns of comparable diameter; however, because of the greater depth of penetration obtained with the jet guns, the total flow rates appear to he approximately equal. Limited testing with an experimental shaped charge suggests that less shot hole restriction and greater flow rates may result from larger-diameter perforations or other factors related to charge design. INTRODUCTION Gun perforating has been accepted for a number of years as a routine well completion method which is often preferred since it permits more selective operation of producing zones. Nevertheless, questions have continued to arise as to the effectiveness of the communication paths established between the productive formation and the interior of the casing. The basis for these questions has generally been failure to obtain anticipated fluid production rates through gun perforated completions in specific wells. These low productivities, together with the frequent recovery of bullets from well bores, were considered strong evidence of inadequate penetration. Laboratory investigations of the penetration performance of many of the bullet guns available as late as 1948 gave support to these indications. Subsequent electrical analog studiesl,2,3 indicated that the depth of penetration required to provide productivities equivalent to open hole was beyond the capacity of most bullet perforators evaluated in the early laboratory penetration tests. These results, together with the advent of the shaped charge in the field of oil well perforating, stimulated the interest of both oil operators and service companies in gun development. Improvements in gun design resulted in jet and bullet guns which appeared to be capable of providing sufficient penetration for most perforating jobs. However, some wells failed to yield satisfactory fluid production even after being perforated with the more powerful guns, again raising the question as to the effectiveness of the perforating operation. This fact, together with preliminary shooting into targets prepared with formation cores, indicated that factors associated with the perforating process and/or the fluids in the well bore at the time of shooting may reduce effective formation penetration and thereby decrease well productivity. These laboratory and field data prompted another phase in the investigation of the effectiveness of gun perforating: a program to determine the extent and seriousness of perforation plugging under simulated well conditions.

Jan 1, 1955