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As 1979 drew to a close, it was obvious that China would have another good year with output of most industrial products at 3-9% above levels attained in 1978. Most increases were registered on the basis of maximum utilization of existing capacities and nationalization of procedures and methods. There were also distinct improvements in the quality and variety of products. Coal output probably surpassed the 650-Mt level in 1979. Steel output was expected to reach the 35-Mt level, an increase of nearly 10% over 1978. Based on the vast amount of housing and road and project construction, cement production more than likely surpassed 70 Mt. The nonferrous base metal industries improved somewhat in 1978, but actual output levels in recent years may have been a little higher than previously estimated by the outside world. Stagnate world demand slowed growth in the "export metals" sector. Minerals like magnesite and talc were produced at tonnages much larger than previously thought, with gold also falling into this category. Sulfur and pyrite production are still short, although a big pyrite mine was being brought into production. Barite out-put was reportedly up and fluorspar output held its own. Westerners generally concede that difficulties in transportation and power supply are holding back mineral production. Throughout 1979, basic construction continued on the majority of projects started by the Chinese and those few foreign projects contracted before the adjustment of industrial priorities. Foreign Ventures Perspective The foreign connection looms large in China's plan for modernization. In effect, it is an extension of what China wants to do in terms of "walking on two legs"-that is, develop what can be done locally to the fullest extent, then rely on international technology to move into the bigger and more complicated projects. Foreign projects are designed to complement domestic projects rather than replace them. Many foreign projects were started or continued by the Chinese in 1979. Building the necessary infrastructure for the projects is usually a Chinese endeavor and requires Chinese technicians and money. In areas with a strong economic base, this activity proceeds without foreign aid. In other areas, added funds are requested. Foreign funds can come in many forms-equipment technology, low interest loans, equity capital, advance-of-funds on the basis of future delivery in kind, and joint venture money. The Chinese are exploring all these avenues, with the strategy of minimizing foreign exchange needs for individual projects. They feel very uncomfortable with high interest rates, even though interest can be treated as operating ex¬pense rather than capital expense. Then there's the question of rights. Will Chinese sovereignty be affected? Can foreigners own land, in addition

Jan 3, 1980

By C. I. Richman

The E h potential during of a iron reducing bacteria such as Aquaspirillum Magnetotacticum (A.M.) can be predicted by a growth model. It also reflects the adsorption of Fe+2 Cu+2 and Mn +2 ions, that can be incorporated into magnetic material called magnetosomes. The Ferric ion concentration during controlled growth of Thiobacillus Ferrooxidans (T.F.) is a function of the bacteria population curve, while A. M. ferrous ion concentration is a function of the integral of the population curve. Charting of the redox potential of T.F. during batch oxidation of refractory ores such as pyrite and pyrrhotite can be helpful to establishing onset and rate the bulk bio-oxidation rate. The onset of biooxidation is marked by an increase in Fe +3 ions that can be correlated with increased growth due to adsorbed electrons.

Jan 1, 1998

By Fred Leighton

Miners have long known that rock noise, or the popping and cracking of the rock commonly heard during mining, can indicate instability of the mine structure. For many years, miners have "listened" to the rock talk and many times have interpreted changes in rock noise activity to be a warning of failure and have retreated from the potential failure area. Microseismics, or the study of rock noises, was begun in the early 1940s partly because of this historical fact. Microseismics is based on using geophysical equipment to detect and analyze rock noises on audible and subaudible levels. Thus, these systems are much more sensitive than the human ear and "hear" even more of the rock "talk" than do miners. Research has shown that micro-seismics can be used to precisely locate portions of a working area that are generating rock noise, and that rock noise release rate information from each area can be used to analyze its stability. On the basis of research results, microseismic systems are now commercially available and have been purchased and installed in many mines around the world. Introduction When a rock mass is subjected to changing stress conditions, such as those caused by mining, small-scale adjustments occur within the rock that release seismic energy. When this energy is in the audible range it is called rock noise. Those areas where stress changes occur are also the areas of the structure most likely to fail. Individual rock noises can be detected and analyzed to determine their precise location relative to the mine structure. Over a period of time plots of this data provide a pictorial representation of where stress changes are occurring. This is because rock noise activity tends to concentrate in those structure areas most actively adjusting to the changing stresses. Since these areas are the most likely to fail, they can be pinpointed and mapped relative to the structure. Rock noise rates, or the number of rock noises occurring per unit of time, also tend to vary dramatically before failure. Thus, the ability to locate the source of individual rock noises provides a means of determining where failure may occur, and rate counting within each area offers a means of assessing when failure may occur. This information, properly treated, can be used to avoid, control, or warn of impending failure. Successful applications of this technique have provided recent impetus to the effort of developing microseismics into a practical, reliable, and economically feasible tool. The phenomenon of naturally occurring rock noise was discovered in 1938 by Obert and Duvall (1939) who were measuring seismic velocities in mine pillars. Seismic energy other than what they were generating continually registered on their recording equipment. Further study by these researchers showed that the extraneous seismic energy being recorded was from rock noises that were being generated within the rock in highly stressed areas. Pursuing this interesting phenomena both in the laboratory and in the field, Obert and Duvall documented the dramatic change in rock noise rate before failure (Obert, 1941). They also established the fact that, in many instances, rock burst failures could be predicted by monitoring and listening to the rock noise activity in rock-burst-prone areas (Obert and Duvall, 1945). These early efforts clearly showed that microseismics had great potential as a tool for measuring or estimating mine structure stability. Extended testing, however, showed that sometimes rock bursts occurred with no apparent microseismic warning, and that at other times sharp increases in microseismic data were not accompanied by failure. Also, because precise location of individual rock noises was not possible at that time, one never knew where the failure was going to occur, only that failure near the observation point was likely. Thus, while the technique clearly offered promise, it was not considered practical then. In the mid-1960s, the Bureau of Mines undertook a new research effort to improve the microseismic technique. Major improvements were judged possible mainly because new and vastly improved electronic and system components had become available as an offshoot of space program instrument development. Thus, in 1967, development of a multichannel, broad band, microseismic system began (Blake and Leighton, 1970). Application of this system in rock-burst-prone mines showed it worked well and provided the incentive to develop methods whereby the source location of individual rock noises could be easily and directly calculated (Leighton and Blake, 1970; Leighton and Duvall, 1972; Redfern and Munson, 1982). The improved system and the ability to locate rock noises quickly showed that the microseismic technique offered new and increased poten-

Jan 8, 1983

By Peng Gao

Coal-based reduction followed by magnetic separation is an innovative technology used in processing refractory iron ores. Given that size is essential to the separation of the metallic iron from the gangue, the morphology of metallic iron particles and their evolution during coal-based reduction are investigated in the present work. The size of the metallic iron particle increased from 128.76 µm to 565.70 µm when the reduction time increased from 20 min to 60 min at 1,225° C and C/O (i.e., the amount of coal addition in terms of the gram-atomic ratio of the fixed carbon in the coal added to the combined oxygen in iron oxides) of 2.5. Based on our microstructural and metallographic analysis, the iron ore reduction process can be divided into three stages: (1) metallic iron particle formation, (2) iron oxide reduction and metallic iron assembly and (3) metallic iron particle growth. Almost all iron oxides are reduced to metallic iron in the second stage. These newborn metallic iron particles are energetically active and able to assemble and grow, and are eventually separated from the gangue. The large metallic iron particles benefit the subsequent magnetic separation process.

By John F. Gamble

Paper 1?South African experience with asbestos-related environmental mesothelioma: Is fiber type important? Neil White, Gill Nelson, Jill Murray The purpose of this review was to illustrate the importance of the type of asbestos in environmental mesothelioma. South Africa is a logical place to assess fiber type. The three major types of asbestos (crocidolite, amosite and chrysotile) were mined (all asbestos mining stopped in 2002) in South Africa. The association between asbestos and mesothelioma was discovered in South Africa. The occupational literature indicates high mesotheliomagenic potential for crocidolite, less for amosite and less still for chrysotile. Since South Africa has been a major source of crocidolite, relatively high rates of mesothelioma in the mining population is not surprising. High rates of mesothelioma due to environmental exposure is surprising, except perhaps when the authors? point out potential sources for community exposures (e.g., mine tailings used for road surfacing, golf courses, brick and plaster making; insulation in residential ceilings; children playing on fiber-rich waste rock). The authors? reviewed four studies reporting on mesothelioma cases and their sources of exposure and fiber type. Overall 23% of the known cases were attributed to the environmental (not occupational) exposure and about 90% were due to crocidolite asbestos. The proportion of environmental mesothelioma is considerably higher than in Western Australia where crocidolite is also mined. There the overall rate of environmental mesothelioma is about 6% (and less than 1% from residence in a crocidolite mining area).

Jan 1, 2007

By Hélio Blak

The Paranapanema Group was created in February 1996 when a group formed by the Brazilian pension funds acquired four companies dealing with nonferrous metals. The new Paranapanema Group, basically related to the tin and construction business, became the sole Brazilian primary copper producer, the second zinc producer and one of the most important producers of copper products, mainly tubes and fittings. To put together such different companies, managed before by family groups and with different cultures and principles, was and still is a big challenge. The strategy of developing and consolidating it as an homogeneous group is based in three pillars: an increase in production, quality and technological improvements on products and market mix and a permanent cost reduction program, using all the potential synergies founded.

Jan 1, 1998

By A. R. Garcia, A. S. Myerson, W. R. Ernst, J. D. Carruthers, M. D. Franke, L. H. Hilzik

A method for removing nickel and vanadium contaminants from spent HDS catalysts involves pretreating the catalyst with H2S followed by extracting the metals with an acidic solution of ferric ion. The ferric ion solution alone removes significant amounts of active ingredients, cobalt and molybdenum; however, by pretreating with H2S, the extraction becomes more selective for removal of Ni and V.

Jan 1, 1988

By F. Mendaña

The characteristics of the igneous and metamorphic bedrock, extra-hard and abrasive, of the Guadarrama Tunnels, a bi-tube project of length 28.4 km without any intermediate attack, are first commented upon. Next, a detailed discussion is given of the most relevant aspects of the performance of the four double shield type TBMs. The experience of this leads to various recommendations to be borne in mind in future designs of TBM having to work in rock of similar characteristics.

Jan 1, 2007

By Jochen Belz, Allan Henneker, Nod Clarke-Hackston

For the construction of tunnels and other underground structures, extraction of the exact amount of material is of paramount importance both economically and for engineering purposes. In the Sequential Support Method (NATM) immediate (sequential)and smooth support by means of shotcrete, steel arches, lattice girders and rockbolts, either singly or in combination are used; cutting of the precise (albeit sometimes of complex geometry) profile is an integral part of the method. In order to save unnecessary excavation and provide better information to the machine operator, VMT GmbH has developed a system to support precise excavation of the tunnel profile when using road headers or other partial face cutting machines. This paper outlines the principles of this system with examples from Australia, Ger-many, Sweden and Spain and will cite examples of typical savings achieved.

Jan 1, 2007

Coal fly ash and flue gas desulfurization (FGD) sludges can be returned to mine pits, fills and revegetation zones in Virginia by regulation if (and only if) a positive beneficial use can be shown. Utilization of alkaline fly ash for control of acid drainage from pyritic coal processing waste piles, and use as a soil amendment for revegetation, are the two dominant beneficial uses proposed over time. Both applications must be controlled by the basic chemical properties of the ash proposed for utilization. Currently, public concerns over long-term As and Se leaching from various applications are increasingly driving regulatory options for mine site utilization. Many fly ash materials are relatively low in inherent alkalinity or neutralizing ability, and certain ashes are actually acidic. Failure to add sufficient total alkalinity will result in strong acidification of the ash utilization zones, stripping heavy metals like Mn, Zn and Cu from the fly ash matrix. Similarly, if alkaline ash is loaded into non-acid forming coal wastes at high rates such that leachate pH is > 9.5, significant leaching of As and Se has been documented in large scale laboratory leaching columns. Utilization of fly ash and FGD as a mine soil amendment for revegetation is based upon combined liming and water holding capacity benefits, however, levels of soluble salts (primarily sulfate and borates) limit one-time application rates to 100 Mg/ha or less.

Jan 1, 2006

By F. Block, K. Kohli

Outcrop barrier pillars serve to keep mine personnel and the public safe from sudden uncontrolled flows of water accumulated in active and abandoned underground mine workings. When an outcrop barrier fails, the result is an outbreak of water to the surface and is termed as blowout. Mine blowouts are associated with above-drainage mines and can occur through the coal outcrop and sealed portals. A blowout is often catastrophic, a threat to the people on the surface living or working in the path of a potentially large flood. In addition, blowouts can destroy homes, cause landslides and severe erosion and release pollution and acid mine drainage. This paper provides guidance on the planning, design, evaluation and inspection of barriers to address the problem of mine blowouts associated with above-drainage coal mines.

Jan 1, 2007

In 1988, at the request of members of the Society for Mining, Metallurgy, and Exploration (SME) Inc., the president of SME formed Working Party No. 79, Ore Reserve Definition. Its mission was to develop guidelines for the public reporting of exploration information, resources and reserves. These guidelines were published in the April 1991 issue of Mining Engineering,(pp. 379-384), and as a document entitled "A Guide for Reporting Exploration Information, continued on an ad-hoc basis until 1996. Working Party No. 79 was then renamed the SME Committee on Re¬sources and Reserves and became a standing committee. Since 1994, the Council of Mining and Metallurgical

Jan 1, 1999

In 1988, at the request of members of the Society for Mining, Metallurgy, and Exploration (SME) Inc., the president of SME formed Working Party No. 79, Ore Reserve Definition. Its mission was to develop guidelines for the public reporting of exploration information, resources and reserves. These guidelines were published in the April 1991 issue of Mining Engineering (pp. 379-384), and as a document entitled “A Guide for Reporting Exploration Information, Resources, and Reserves” in January 1992. Work continued on an ad-hoc basis until 1996. Working Party No. 79 was then renamed the SME Committee on Resources and Reserves and became a standing committee.

Jan 1, 1999

With the rapidly growing use of hydraulics in mining equipment, maintenance personnel should be familiar with the various components in hydraulic systems. Hydraulic systems do wear out - the fluids they transport are hot and turbulent, the equipment they power often imposes tremendous pressure pulsations and bending stresses, and the working environment is harsh. Therefore, even though hydraulic hoses are made of remarkably trouble-free components, they do need to be replaced periodically. There must be coupling methods that allow hoses to be replaced without disturbing other components. Couplings must also provide a variety of leak-resistant connections between hoses and other components in the hydraulic circuitry. Threaded Connection and Seals Hydraulic coupling thread ends and sealing arrangements are standardized, with many types available. Their outward appearance varies, but coupling configurations are recognizable by examining threads and seals and comparing them to the examples provided here. Iron Pipe Thread There are two kinds of iron pipe threads normally used in mining equipment circuitry - National Pipe Tapered Thread for Fuels (NPTF) and National Pipe Straight Thread Mechanical Joint (NPSM). The NPTF seal is the engagement of the coupling threads, called thread interference. When tightened, the tapered thread of the male fitting binds into that tapered thread of the female fitting to form a relatively leakproof seal (Fig. 1). In the NPSM seal, there is a 30° angle seat machined into the end of the male NPTF fitting. This seat engages with a mating 30° angle cone on the inside of the female fitting. Female NPSM fittings have straight threads, as opposed to the tapered threads of the NPTF fittings. However, most NPTF solid male fittings also have a 30° angle seat enabling them to be used with NPSM female fittings (Fig. 2). JIC and SAE Fittings Joint Industry Conference (JIC) and Society of Automotive Engineers (SAE) seals are formed by joining two mating, conical metal surfaces. The coupling threads are used to bring and hold these surfaces together to form a leak-resistant seal. A JIC connection is a solid male threaded end, with a 37° machined male nose, mating with a 37° female flare seat. When connected, the mating surfaces are held together by the threads, but the threads do not form the seal. The female seat is created by flaring a tube end or machining the interior surface of a stem to 37°. A female JIC has a swivel nut, allowing the sealing surfaces to be joined together without twisting a hose or twisting the seats against each other (Fig. 3). JIC couplings are frequently used on low, medium, or high pressure hydraulic circuits on mining equipment and machinery. The SAE connection is similar in appearance and sealing characteristics to the JIC system, except the angle of the machined male nose and female flare seat is 45° (Fig. 4). "O" Ring Fittings Seals for "O" ring fittings are formed by compressing an "O" ring against an exposed machined surface on a mounting block or hydraulic component part. The "O" ring must be compatible with the type of hydraulic fluid used (Fig. 5). An "O" ring boss connection is made of a male straight thread

Jan 10, 1983

By Pierre Mousset-Jones, Felipe Calizaya, Malcolm J. McPherson

The objective of this study is to provide potential users of booster fans in coal mines with the necessary information on monitoring and control of fans and environmental factors. The guide-lines listed in this paper were formulated based on the current practice of mine monitoring, the U.S. Code of Federal Regulations on environmental monitoring, and the United Kingdom's National Coal Board recommendations on the use of booster fans. The principles involved in the design of booster fans as well as the provisions needed to guarantee a safe operation of these units, are illustrated by means of an example problem. The example includes a summary of costs for two ventilation systems: a conventional surface fan system and a fully automated booster fan alternative. A comparison of these costs showed that significant gains may be attained by selecting a combined surface-booster fan strategy over a conventional surface fan alternative.

Jan 1, 1989

By D. P. Bryan

The identification and-develop¬ment of new construction aggregate resources, the most common mineral mined, is an essential need in this country's growing urban areas. In developing an aggregate exploration program, a thorough geological identification of all potential aggregate resources in an area is still of primary importance but other factors have also to be considered. These include physical properties, end product application, transportation and mining costs, and local government regulations including zoning. The present major aggregate producers are most likely to develop these future resources and are in the best position to initiate comprehensive exploration programs.

Jan 1, 1987

By R. H. King

Underground coal mining machinery utilizes portable electric sables, "trailing cables." to obtain power from load centers or distribution boxes. Cables are frequently damaged since mobile equipment, poor lighting, and restricted space are inherent to coal mining operations. Normally, the damage is repaired by splicing--the joining of one or more severed conductors and replacing insulation and jacket. Figure 1 illustrates a typical single conductor splice. Although the repair seems simple, difficulty of the splicing process is exemplified by the many safety hazards and frequent production delays that result from defective splices. Forty-two cable splice related injuries were reported to the U.S. Bureau of Mines in 1972 and 1973. Additionally, 17 splices related fires were reported in the three year period prior to December 1972. Assuming the damaged area is quickly located, an average splice time for a two conductor cable is twenty minutes. Some operators estimate this delay is incurred once per day per operating section. If one ton per minute is averaged throughout the shift, each unit could loose 4800 tons per year from splice delays. An estimated cost for materials and labor to make a splice is $20. The expenditure could result in a $4800 annual cost per section. The estimated expense does not include wages of other personnel waiting for the repair to be completed. Nevertheless, labor and materials cost is minor compared to the income lost from decreased production.

Jan 1, 1975

By F. Calizaya, M. G. Nelson

This paper presents a summary of basic requirements for the design, installation and operation of booster fans in coal mines, especially in deep and/or extensive mines. It includes a brief description of the major steps that should be followed to ensure that these units are used in coal mines safely and efficiently. The guidelines were prepared based on the standards and regulations adopted by two prominent coal mining countries, the best practices developed by the mining industry, and the applicable standards used in the United States for the fail-safe operation of main fans.

Jan 1, 2015

By Paul D. Tomlingson

Part one of this two-part series covers conceptualizing and developing a maintenance information system. It explains what information is necessary to manage such a system. Next month, part two will discuss using this type of system with administrative information, including error and absentee reports as well as open work files. Introduction There is no doubt that quality, timely, and accurate information can make a solid contribution to maintenance cost reduction objectives. Yet, despite obvious benefits, methods being used to acquire information systems are proving costly, frustrating, and often unsuccessful. Those needing the information are disappointed. Mine managers, hoping to reduce costs with quality information, are instead seeing no system, no savings, and massive spending on information endeavors of questionable benefit. Options Any software vendor will happily sell you his program. Numerous mining organizations, having "gone to the cleaners" themselves, will gladly make their programs available to help cover huge trial and error development costs. Any package can only be a generalization. Any program bought from some other organization must undergo numerous modifications to make it work properly. In the process the initial cost is doubled. Many mining maintenance organizations do not know how to go about the task of conceptualizing, developing, installing, and effectively using a maintenance management information system. Consequently, many have hedged their primary responsibility of specifying what information they want, how they will get it, and how they will use it effectively. Into this void have jumped many who claim they can help. But some may not understand the special information needs of maintenance in the mining industry. By default, the whole scene of maintenance information systems has become confused and in need of clarification. A Starting Point Four broad phases are used to organize the steps by which maintenance acquires an effective maintenance management information system and initiates its use. Conceptualization is an identification of needs, factors that influence development, and an assessment of support for the system. Development is a plan of action for bringing the conceptualized information system to life. Consideration is given to the practical aspects of collecting field data, processing it, and converting it into useful information. Implementation consists of those actions by which the newly developed system is integrated into the organization and put in the hands of its personnel so that its value can be derived. Use addresses the means by which personnel use the information to accomplish maintenance improvement objectives. These phases are preceded by establishing the need for the information system. They are followed by a requirement to measure its success (Fig. 1). Conceptualizing the Information System Responsibilities - The information system user must acquire the system best suited for its use. A step-by-step process is essential to avoid many serious problems than can easily occur. The most important step is to clearly identify its objectives and lay out a course of action to achieve those objectives. The major reason for the failure to achieve information objectives is not carrying out this responsibility. Maintenance cannot delegate the task to data processing. It can obtain technical assistance but it must retain responsibility. Nor can maintenance purchase

Jan 7, 1985

By Sarkis G. Ampian

This late 1979 Bureau of Mines report presents current stocks and monthly consumption rates for Guyanese refractory bauxite (GRB), with emphasis on the impact of the GRB shortage on the refractory and downstream industries, general background material, and an evaluation of the situation resulting from the strike of Guyanese bauxite workers during the summer of 1979. A study by the Bureau indicated that industry stocks contained little more than a month's supply of GRB--30,000 calcined short tons (CST), at present consumption rates of 25,000 CST per month. The report was requested by the Federal Emergency Management Agency (FW) in response to refractory industry requests that the Government release GRB from the National Stockpile to minimize forecasted industry problems. The report traces the historical innovations in the high-alumina and/or bauxite-type refractory products industry, eventually leading up to fabrication of modern, high-quality firebrick and monolithic refractories.

Jan 1, 1980