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By D. R. Maneval

The vast coal resources of North Slope, Alaska, can be expected to attract substantial interest because the nearly flat-lying coal beds of the coastal plain are specially amenable to surface mining. Mining on a scale large enough to justify coal development in this area could have severe environmental effects. The mitigation would be uncertain because large-scale coal mining and reclamation operations have not been carried out in the arctic. The deficiency of the scientific data base is another factor that requires consideration if coal mining has to develop in accordance with the objectives of PL 95-87. The objective of this paper is to establish the inter-relationship between the problems due to permafrost and factors in reclamation of post-mining land in order to find ways to transform nature in a rational and purposeful manner and to suggest specific reclamation approaches that may be appropriate in this region.

Jan 1, 1987

By N. R. Billette

In 1982 and 1983, a study was undertaken to analyse the applicability of Elbrond?s analytical model to suit the needs of Lake Asbestos of Quebec in their computerized open pit planning and scheduling strategy. The immediate goal was the assessment of the optimal allocation of trucks and the determination of the extra cost of in-pit blending. Data from 45 tonne trucks was used to estimate the mine capacity based on a fixed assignment policy. The tonnage yielded by the analytical model was compared with the results of a simulation program. Another point that the study high- lighted was the definition of efficiency parameters for the haulage system: shovels-trucks-crusher. The efficiency, both of the utilization of financial resources and of the operations, for the overall system reaches optimal values in very precise conditions for the number of pieces of equipment in operation. Such a parameter is proposed as a standard for the definition of an optimal number of trucks and shovels in operation. Deviations from this optimum do occur in a well-planned system for qualitative goals. These can then be quantified in terms of costs to the mining company.

Jan 1, 1986

By John Jonkman

Many companies in the mining and minerals processing industry are finding themselves in the transition stage from the Industrial Age to the Information Age and are trying to become prepared for the Knowledge Age. To remain competitive in the decades ahead, they are faced with integrating the enterprise through the use of computers and networks. This paper discusses some common human and organizational barriers to enter- prise integration. It proposes how to develop the organizational and human' networks to match the capabilities of the technical networks which are being' implemented. Ten practical considerations are then presented for consideration in the executive suite in addressing the human side of implementing the computer integrated enterprise.

Jan 1, 1989

By M. K. Gangal, E. D. Dainty

The CANMET diesel-related work, carried out in cooperation with the Canadian mining industry, resulted in the identification of several useful R/D studies. One such study was the development of a dash-mounted alarm signal system to indicate overexposure of production LHD diesel vehicle operators to toxic contaminants in a mine environment. The resulting instrument has been called the [CO2 Exposure Meter]. This meter is particularly applicable to LHD machines because previous investigations have indicated that operators of LHDs and some haulage truck drivers are exposed to up to 200% of the contaminant concentrations measured in the general mine return air. This paper describes the development of the system which continuously monitors and displays the operator's exposure to diesel pollutants, and indicates an overexposure by an alarm light. The overexposure limits are preset by mine personnel based on carbon dioxide (CO2) measurements, which in turn are related to simultaneous spot respirable combustible dust (RCD) measurements (or to Air Quality Indices - AQI, if available). The CO2 settings are, in general, related to the engine/exhaust treatment selections, vehicle duty cycle and local ventilation rates and efficiency. The system continuously displays one of three lights: green for underexposure, yellow for caution, and red for overexposure. Overexposure can occur for several reasons, such as: reduced ventilation, malfunction of the diesel vehicle, and excessive airborne contaminants. The paper confirms satisfactory operation of the system in a laboratory-simulated mine environment, as well as in field trials.

Jan 1, 1993

By Alberto S. Nieto

The general role of geology in the location of different types of large underground chambers is discussed. Aspects of structure, rock type and state of stress are discussed at some length. Some practical implications on stability of observations about the attitude, spacing and persistence of structural features are made. Characteristics and likely problems inherent to rock types (igneous, metamorphic, and sedimentary) are discussed. Observations regarding the uniformity of stress conditions within a physiographic province are presented. The influence of stresses parallel to the chamber axis on wedge movements is briefly discussed.

Jan 1, 1983

By D. M. Walters, C. M. van der Vyver, L. J. deVulliers

The occurrence of underground fires in narrow tabular ore- bodies where high density timber support is used is a dangerous and disruptive occurrence. The containment and extinguishing of the fire remains a very important consideration in reducing not only the loss in production time but also in limiting the extent of the area damaged by the fire. Mindful of this, Gold Fields have adopted and developed the inert gas generator system from its origins in Poland for use in Group precious metal mines. The system generates an oxygen- deficient atmosphere which is introduced in the fire area after this has been sealed. A number of problems had to be overcome to operate this system successfully within the infrastructure of these mines. Of particular significance is the operation of a jet engine, the prime component of the system, at air pressures encountered below sea level. The modifications have been found to be satisfactory to the point where, since 1992, ten underground fires have been extinguished using this system. Invariably, the areas affected by these fires were extensive (over 1 000 000 m3) and required continuous operation of these units over extended periods of time (in some cases in excess of 400 hours).

Jan 1, 1997

By K. C. Jordi

Many systems which are modelled mathematically result in a model where the relationships between some or all of the parameters are found to be non-linear. These systems are usually complicated further by a desire to make the system achieve multiple and often conflicting objectives or goals simultaneously. Rozwadowski (1970) developed a model to describe the total discounted net profit of a mine as a function of the amount of ore developed and of the grade of the amount of ore mined. Dynamic programming was used to determine the policy which gave the maximum net present value. In this paper it is shown that the relationships between the variables can be approximated by piecewise linear functions. This is amenable to solution by an algorithm based on the simplex algorithm of linear programming. The goals of maximizing the net present value, the total net profit and the total gold output are incorporated simultaneously into a goal programming formulation of the system. The resulting model is characterized by a large number of disconnected constraints. These are decomposed into several smaller problems and the problem solved. The solution is examined to discover the sensitivity of the system to changes in certain parameters. In particular the interaction between the three goals is analysed to determine whether there is conflict between any of the goals and, if so, what the trade-offs between the conflicting goals are.

Jan 1, 1979

By Jim Peregoy

INTRODUCTION Frontier-Kemper Constructors, Inc. is an Evansville, Indiana based heavy construction contractor engaged in projects for both the public and private sectors of the underground construction industry. Construction activities range from conventional shaft, slope, tunnel and chamber excavation through state-of-the-art mechanical excavation, ground freezing, standard support and structural concrete operations. Conventional excavation and concreting equipment, as well as raise boring machines, road headers, tunnel boring machines, and freeze plants are owned, operated, maintained and modified "in-house" to suit the needs of individual projects. The balance of this paper wilt present a general overview of the Frontier-Kemper planning and construction operations on the recently completed Phase II of the U.S. Army Corps of Engineers, John Day Dam, Juvenile Fish Bypass Project. General Project History The U.S. Army Corps of Engineers is responsible for designing, constructing and maintaining various navigation and impoundment structures on the nation's inland waterways. Maintenance involves both the work required to maintain the structure in fully-operable condition and the ongoing work required to maintain a positive impact on the environment. John Day Dam is located on the Columbia River approximately 95 km (60 miles) upstream of The Dalles, Oregon. It was constructed to: provide electric power to the Pacific Northwest; provide Locking for up-and-downstream bound commercial and private watercraft; act as a water impoundment structure to control flooding conditions; and to provide a source of irrigation water

Jan 1, 1987

By Ishwar G. Mulani

In conveyor design, the first step is capacity and the second step is belt width and speed. The third step is decision on 'ff," where distinction arises between DIN/ISO and CEMA for calculating resistances. Then again, both the methods are virtually similar. This topic helps in understanding Dm design style and its comparison to CEMA. This topic is from the book Engineering Science and Application Design for Belt Conveyor wherein the issue has been analysed in detail. It presents a workable calculation model to calculate the value off in design office, based on conveyor parameters. CEMA uses Kx, Ky and 0.01 5 instead off. Thus, f is a sum effect of Kx, Ky and 0.015. Hence, knowledge on f is also applicable to Kx and Ky. This helps to understand their relationship.

Jan 1, 2004

By Douglas E. Rawling

The successful genetic manipulation of T. ferrooxidans is partly dependent on an understanding of the molecular biology of the organism. For optimum controlled expression of foreign DNA in T. ferrooxidans it is important that donor DNA is derived from bacteria that are genetically similar to T. ferrooxidans or placed under the control of T. ferrooxidans transcriptional promoters. Several structural genes and their controlling regions from T. ferrooxidans have been isolated and their DNA sequenced. These include the genes that encode the nitrogenase enzyme (nifHDK genes), glutamine synthetase (glnA gene) and the recA gene. These genes and the identical genes from a wide variety of other bacteria have been compared at levels of DNA sequence, protein sequence. Where possible, gene expression as well as transcriptional control and protein function of the cloned genes were tested in the enteric bacterium Escherichia coli. The two genes involved in nitrogen metabolism were either expressed or possessed the necessary elements for expression in other bacteria. In contrast the recA gene was not expressed in E. coli from its own promoter. The two gene products that would be tested (glnA and recA) were fully functional in E. coli. The relevance of these findings to the genetic manipulation of T. ferrooxidans is discussed

Jan 1, 1989

This paper details the development of a functional work index that characterises the relationship between the energy that is imparted by a Roller Press into materials, against the resultant size reduction achieved. Such a Roller Press work index is necessary for this new grinding technology to differentiate it from Bond's grinding work index, and to clear up confusion that arises with such a comparison to Bond. The energy usage in a Roller Press does not follow Bond's "Third Theory of Comminution" but rather Rittinger's theory of new surface creation. The relationships for such a work index have been developed from the viewpoint of an equipment manufacturer with the hope that they will be of assistance to the minerals industry in the design of grinding circuits incorporating Roller Press comminution. The work index contains modification factors that reflects the effect of oversize, fines, moisture. closed-circuit operation and roll surface characteristics on the energy verses size reduction relationship. It has evolved from the results obtained from testing of a wide range of ore and mineral types that include bauxite, coal, kimberlite, limestone, iron and chrome ores, base metal and gold ores. The results show that even for such a diverse range of materials, they all demonstrate similarities of behaviour when comminuted in a Roller Press.

Jan 1, 1997

By Tom McDonald

Test work and plant operation confirmed that semiautogenous (SAG) milling is a viable option for Inco's milling rationalization project at Sudbury only if pebble crushing is included. Throughput increases more than 50% with pebble crushing incorporated into the comminution process. The finer product of high-speed pebble crushing provides further energy savings. The unconventional approach of pumping the pebble crusher product, while simplifying plant layout, has produced challenging wear problems. Inco Ltd.'s Sudbury operations are located in northeastern Ontario, Canada, about 400 km (250 miles) north of Toronto. Inco has 11 operating mines around the rim of the Sudbury basin. The mines currently produce about 11 Mt/a (12 million stpy) of ore. This ore contains pentlandite, pyrrhotite and chalcopyrite in mafic host rocks. The milling facilities are designed to produce 108.8 kt/a (240 million lbs/ year) of nickel as concentrate. This concentrate is further processed through Inco's smelting and refining facilities to produce nickel, copper and several other metals. Before 1991, -200 mm (-8 in.) ore was shipped to two primary mills. The Clarabelle mill had a design capacity of 29 kt/d (32,000 stpd). Frood-Stobie had a capacity of 16.3 kt/d (18,000 stpd). The flowsheets of these mills were similar. Two stages of open-circuit crushing were followed by rod milling and closed-circuit ball milling. The product from the comminution circuit, at 12% +250 mm (+65 mesh), was first passed through magnetic separators to recover magnetic pyrrhotite. It was then sent through a four-stage flotation process. The first two stages produced a high-grade copper-nickel concentrate. The final two scavenger stages produced a low-grade copper-nickel concentrate containing nonmagnetic pyrrhotite.

Jan 1, 1992

By G. B. Misra

Heat transfer in partially wet mine airways has been the subject of study for quite some time. Of the available models some are quite empirical while some involve highly complicated computation. Models developed by Amano, Mizuta and Hiramatsu and Banerjee and Chernyak as well as that modified by Misra were evaluated for prediction of the rise in temperature and humidity (mixing ratio ) of partially wet mine airways at four different levels in the Mosaboni Mine of Hindustan Copper Ltd. Measurements of barometric pressure, virgin-rock temperature and changes in dry- and wet-bulb temperatures along a certain length of airway were made. The rise in dry-bulb temperature and mixing ratio of air over the sections were calculated using the three models. The study reveals that calculated values of temperature and moisture content agree within possible rage of experimental error with all the three models in case of three levels with low wetness factor, but the agreement was poor for the relatively more wet airway on the 30th level. Errors in the estimation of fw to the tune of 0.025 can lead to fair error up to 0.94 K in the estimated temperature while alternative ways of estimating the heat transfer coefficient [] can introduce errors up to 1.45 K.

Jan 1, 1987

By Robert C. Jones

The Henderson Mine, a new large scale underground development, is being developed by AMAX. The mine site is located about 50 miles west of Denver, Colorado, adjacent to the east side of the Continental Divide. The mine's three access shafts are in a narrow alpine canyon at an elevation of 10,400 feet. The ore body of molybdenite is to the south of the shafts, 3,000 feet below the surface of nearby Red Mountain. The ore extends over 800 feet vertically and is about 1,700 feet by 2,200 feet horizontally. The eastern and southeastern boundaries of the deposit are still to be defined at the present time. Development mining is advancing at the mine site on a three shift, seven-day basis at the rate of about 2,000 feet per month. About twelve miles of heading have been driven at the present time, and work to sink No. 3 Shaft has started. Development mining was begun in 1967 with the sinking of No. 1 Shaft. This shaft is fully concreted, 23 feet in diameter and 2,441 feet in depth. It is the mine ventilation exhaust conduit. It is also used for development muck hoisting, stand-by mine water pumping and secondary access to the 8,035 foot level. This level is the mine exhaust ventilation level and was mined principally by conventional rail mining methods. From this one station at the 8,035 foot elevation a 5% ramp was driven to the initial production horizon at 8,100 feet with diesel rubber tired mining equipment. Subsequent mining has been entirely by mobile diesel equipment at the mine site.

Jan 1, 1974

By Agne Rustan

Most of the mines in Sweden are metal ore mines in hard rock and none of these mines are classed gassy because there is no methane emission. The risk of methane explosions in Swedish mines is therefore very small. Since the 1960?s, in Swedish mines, there has been a change from electric and pneumatic loaders and transport machines to diesel. Today in almost all Swedish underground mines diesels are used. One of the most common complaint from the underground mine- workers is the exhaust gases from the diesel-vehicles. This is a strong motive for attempts to assure a more comfortable environment. Another motive for a better efficiency of ventilation under ground is the increasing cost of energy for fans and for heating the air during winter. For the largest mine in Sweden, the Kiirunavaara Mine, 36% of the energy for ventilation is used for preheating the air during the seven months when the temperature is below zero. The air quantities used for ventilation are large. In table 1 a comparison of the ratio between yearly produced ore and waste rock and installed fresh 'air capacity is shown. [ ]

Jan 1, 1980

By Por J. B. Evans

El mantener un beneficio óptimo sobre todo el conjunto de un emplazamiento minero necesita una constante puesta al día de las estrategias operativas. En esencia, cada estrategia es una combinación particular del gasto del capital previsto, el flujo de ingresos y el tiempo transcurrido. La selección de una estrategia basada en el beneficio potencial requiere que cada estrategia contemplada con un ordenador, un análisis tal puede ser engorroso. Este capítulo discute o desarrolla una técnica de "corte rápido" que asigna una relación de beneficio a las estrategias alternativas e identifica aquellos aspectos de una estrategia que producen mayor impacto sobre el beneficio. Esta técnica puede proporcionar valoraciones rápidas de suficiente precision para muchas de las decisiones de las estrategias operativas que se toman sobre la marcha en minas que se encuentran en explotación.

Jan 1, 1982

By Stanislaw Nawrat, Waclaw Dziurzynski

An increasing concentration of coal production, especially in the circumstances of intensive methane inflow makes the coal mine managing staff apply new techniques of safe mining. It paves also the way for scientists to develop new directions of investigations and implementation of state-of -the- art technical solutions. Simultaneously, it could be noticed that the funds assigned for expansive 'En situ ' investigation are continuously decreasing. Better and better results are reached when applying computer technique in calculations of the parameters of ventilation process. Recent theoretical and experimental investigations of air and gas (methane) flow in longwall areas with caving, combined with the implementation of methane drainage system allowed to create, a mathematical model and consequently to elaborate a computer supported numerical simulation of discussed phenomena. The mathematical model has been modified and the simulation program was prepared in such a way that the software is convenient for a user looking for an optimal solution. The paper presented the methodology of optimal choice of following parameters: - ventilation system - rate of flow through the wall. The procedure takes into consideration keeping a safe level of concentration methane in air flowing through the longwall as well as the criterion of maximum methane concentration within the methane drainage pipe line. Results of variant computer simulation regarding the longwall with caving are shown in graphs and tables.

Jan 1, 1995

By M. K. Gangal, E. D. Dainty

CANMET/MRL has been contributing to an industry/government program to assess the quality of air in mines, and improve the working environment for Canadian miners. The ultimate aim of this program is to recommend a sampling methodology and appropriate concentration limits for both the soot (diesel particulate matter - DPM) generated by diesel equipment, and respirable combustible dust (RCD) as measured underground. The program was conceived by the Canadian Adhoc Diesel Committee, which consists of representatives from seven major Canadian mining companies, three provincial inspectorates, one union representative, two manufacturers of diesel equipment, and CANMET, a Federal Canadian research agency. This paper describes the modification and laboratory confirmation of an existing methodology for the sampling and analysis of DPM/RCD, including: sampling problems, filter selection, filter efficiency, DPM size distribution, the approximate performance of fractionating devices, and it reports the results of current ambient measurements of exposure levels in Canadian underground mines. Because of the concern about the health impact of DPM/RCD on mine workers, North American agencies are in the process of establishing limits for these aerosols. So far, the Province of British Columbia is the only jurisdiction in North America to legislate the maximum exposure level of RCD in its underground mines, i.e. 1.5 mg/m3 interim level recommended by the Adhoc Diesel Committee. It has also recommended the use of the CANMET/ADHOC RCD sampling protocol.

Jan 1, 1993

By Robert W. Waytulonis

Miners working in underground mines where diesel equipment is used are exposed to exhaust pollutants. These include carbon monoxide (CO), carbon dioxide (CO,), nitric oxide (NO), nitrogen dioxide (NO2), sulfur dioxide (SO2), hundreds of different hydrocarbons (HC) and particulate matter. Evidence from animal inhalation studies and limited epidemiological investigations have led the National Institute for Occupational Safety and Health (NIOSH) to recommend that ‘... whole diesel exhaust be regarded as a potential occupational carcinogen ...’ NIOSH further stated that ‘... the excess cancer risk for workers exposed to diesel exhaust has not yet been quantified, but the probability of developing cancer should be decreased by minimizing exposure…’ The International Agency for Research on Cancer(IARC) reached a similar conclusion, saying that ‘... diesel engine exhaust is probably carcinogenic to humans.’ Before these declarations, there was insufficient evidence concerning the carcinogenicity of diesel exhaust. It was well known, though, that diesel exhaust caused less severe problems, such as headache, eye irritation and unpleasant odors. In 1988, a milestone was reached in the Mine Safety and Health Administration (MSHA) regulatory process. An advisory committee recommended a three-tier approach to regulating diesels used underground-approval of diesel equipment, safety and health. Diesel particulate matter may be specifically regulated. In addition, ambient air quality standards are being proposed that will establish a new standard for CO2 and lower the permissible exposure limits for the NO2, CO, SO2 and formaldehyde emissions that originate from diesels and other sources. Additional safety and emission restrictions are also proposed for diesel engines in coal mines. The goal of the US Bureau of Mines (USBM) diesel engine research program is to minimize the health and safety problems associated with underground diesel equipment use. Part of this program is focused on reducing exhaust emissions from diesel-powered equipment used in underground mines.

Jan 1, 1993

By Stephen R. Pogorski, Nicholas Busigin, Colin R. Phillips

The movement of radon away from its source in porous media is determined by two key parameters: the fraction of the total radon formed which enters the intergranular pore spaces, termed the emanation coefficient, and the transport processes which exist in these pores such as diffusion and convection. The first parameter, the emanation coefficient, is of primary importance since it is a measure of the actual amount of radon which is free to migrate within the media. The effects of particle size and radium concentration on the emanation coefficient were examined using a quartz-pebble conglomerate ore from the Elliot Lake mining district of Ontario. It was found that the smallest particle size examined (<74 µm) had the highest radium concentration and contributed the most to the radon emanation. A one-to-one correspondence between radium concentrations for the various particle size fractions and radon emanation was not observed. Samples were examined using scanning electron microscopy and very small particulates were observed to be present on the particle surfaces. When these very small particulates were removed from the host particle surfaces by rinsing, the radon emanation decreased by a factor of 17. This result indicates that most of the emanation comes from the very small particles. The effect of moisture on the emanation coefficient was examined qualitatively and a trend of increased radon release with moisture content was noted.

Jan 1, 1981