Search Documents

By B. K. Parekh, R. H. Mehta

The handling of fine coal is an important issue for both the coal and utility industries. Reconstitution of fine coal in the form of pellets or briquettes would be desirable if it could be done economically. This paper evaluates the effectiveness of three binders, asphalt-emulsion, corn starch and Brewex, informing pellets of ultrafine clean coal. It was found that asphalt-emulsion and corn starch were not effective binders. However, the use of Brewex resulted in pellets that exceeded all of the minimum quality requirements for coal pellets.

Jan 1, 1997

By Haydn H. Murray

A hydrothermal bentonite located in the high Sierras in Nevada is being mined and processed to produce a natural dietary supplement. The minerals present are smectite, gypsum, jarosite, quartz, feldspar, kaolinite, goethite, hematite and zeolite. The clay material was analyzed for respirable crystalline silica, asbestiform minerals, heavy metals and dioxin. No asbestiform minerals are present and the crystalline silica, heavy metals and dioxin are all less than the maximums set by Federal and State agencies. The clay material was analyzed chemically for all major, minor, trace and rare earth elements. The geology, applications and analyses will be discussed in the paper.

Jan 1, 2005

By H. Wesley Peirce

Arizona, in 1966, has continued to be the site of an extensive and intensive search for metallic mineral deposits. Over fifty separate entities--companies and individuals--have been actively engaged in mineral exploration programs, both large and small, in the Basin-and-Range portion of the State. Certainly, copper has been primarily responsible for the major efforts, although associated gold, silver, and molybdenum mineralization also has been important in the economic evaluation of potential copper deposits. It is not difficult to explain why the Basin-Range portion of Arizona is receiving such attention. Part of the story, undoubtedly familiar to most, can be illustrated by reference to three graphical presentations. For example, Figure 1 shows Arizona's annual copper production for the period 1955-1965, inclusive, and it demonstrates that new records of production have been accomplished in each of the past 6 years and in 9 of the last 11 years.

Jan 1, 1967

By Brian T. Hamilton, Richard Piliounis, Cian Murphy

"The Eglinton-Crosstown Light Rail Transit line is a 19-kilometre corridor with a 10-kilometre underground portion currently being constructed by Metrolinx in Toronto through a densely populated urban environment. Tunneling works are being completed through two separate design-bid-build contracts that include consideration for a phased handover to a follow on contractor who will take ownership of the tunnels, including warranties, and will complete the stations and remainder of the system through a PPP delivery model including maintenance of the system for 30 years. Warranty provisions, settlement apportionment, tunnel leakage, potential delays and conflicts between contractors are just some of the risks the team managing tunnel contract integration had to consider when developing the PPP contract. This paper will present an overview of how these risks were assessed and allocated through the contracts and the strategies adopted to minimize risks to Metrolinx while ensuring successful procurement was maintained. INTRODUCTION The Big Move is a 25 year, $50 billion ($-CAD) plan for coordinated and integrated transportation in the Greater Toronto and Hamilton Area (GTHA) in Ontario, Canada. This plan has been initiated by Metrolinx, a division of the provincial government of Ontario, and its vision, goals and objectives are rooted in creating a high quality of life; a thriving, sustainable and protected environment; and a strong, prosperous and competitive economy for the GTHA. The Big Move will triple the length of rapid transit service in the GTHA to 1,725km, significantly increase the percentage of the GTHA population living within two kilometers of rapid transit, reduce commute times to an average of 77 minutes per person per day and decrease greenhouse gas emissions from passenger transportation per person by 29%. Work is currently underway on several projects and more than $16 billion ($-CAD) of the planned investment has already been committed. A key project that forms part of this commitment is the Eglinton Crosstown Light Rail Transit (LRT) Project which is being delivered in the City of Toronto under Metrolinx’s Rapid Transit (RT) Program. This complex and sizeable undertaking has been broken into a number of separate contracts comprising: LRT Vehicles contract; Eglinton West Tunnels Project; Eglinton East Tunnels Project; and a Public-Private-Partnership (PPP) contract to complete the underground stations, at-grade stops, all rail infrastructure and systems and to maintain the entire system for 30 years. The PPP contract, which includes an initial capital portion of approx. $5.1 billion ($-CAD), has recently been awarded to Crosslinx Transit Solutions, a Special Purpose Vehicle (SPV) consortium comprised of SNC Lavalin, Aecon, Dragados and EllisDon."

Jan 1, 2016

By John A. L. Dr. Campbell, James W. Haskew, F. Hoy Lee, Elliott P. Dr. Doane

Emissions of particulates, unburned hydrocarbons, nitrogen oxides (NO[ ]) and carbon monoxide (CO) from diesel engines are of concern in mines, particularly underground mines. All these undesirable products except NOx are the result of incomplete combustion in the cylinders. Various approaches to achieving more complete combustion in diesel engines have included different fuel compositions, use of catalysts, fuel additives, engine modifications, and oxygen-enriched intake air. The present study shows that injecting minute quantities of primarily platinum group metal catalysts into the intake air of a Deutz/MWM D916-6 mine diesel engine substantially reduces emissions in the exhaust. The catalyst injection system, which was developed by National Fuelsaver Corporation (Robin. 1981), transfers catalyst compounds in solution to a stream of air bubbles by a process called Bubble Fractionation (Lemlich et al.. 1966, 1968. 1970). The amounts are so minute that concentrations in the engine exhaust should be well below OSHA/NIOSH Time Weighted Average (TWA) exposure limits at steady state, a fact that was confirmed by analysis of collected particulates in the exhaust. When the catalyst injection was used along with a pleated paper filter to remove exhaust particulates, the filter operating life was shortened greatly. Therefore, this system is not recommended for use on diesel engines equipped with a water scrubber and a filter. It does offer a practical and relatively economical way of reducing exhaust emissions from other diesel engines, such as those in outby mine service

Jan 1, 1995

By Spencer R. Titley

The subject of this lecture, a late century perspective on porphyry copper geology, is one of current interest and importance as the search for these ores remains intense. It is presented in the belief that an appreciation of our present understanding of the subject requires it to be viewed historically, thus providing a basis for evaluating appropriate directions for con¬tinued study. At the outset, it is important to note that the technology of mining and extractive metallurgy has developed ore from these low grade orebodies, starting with D. C. Jackling, and has continued to create them as copper grade and price have diminished. But the continued search for them is a geological problem that responds to growing expectations of people and societies; exploration based upon ever increasing knowledge of the habits of the ores has been very successful. This is the story of evolution of geological thought and practice in porphyry ore search across an interval of time beginning with the bulk mining of "low grade copper ores at Bingham and ending with late Century concepts. "How did we get here?" The lecture concerns the ideas of many different people. The ideas and events discussed reflect a bias on North American thought, where the great low grade orebodies were first recognized as such and where many of the basic geological ideas were developed. A very great number of geologists have contributed to this understanding. In no sense is it meant to minimize the contributions to the story that have evolved in the study and mining of ores of the Andes, whose development and expansion has been nearly synchronous with that in North America - nor to minimized comparable contributions made in the late century from studies of the newer discoveries of deposits in other regions, especially the southwestern Pacific regions. In expansion of this topic, I have found that many important concepts are marked by appropriate publication but some are not, or I have not been able to discover documentation. Many notions appear to have become conventional knowledge without publication, mostly being geological viewpoints developed synchronously from similar observation. Thus, apologies are extended in advance to those whose work I have might have missed and to those unknown to me whose unpublished ideas may have seeped into the pool of common knowledge without appropriate recognition. . The analysis here addresses events of two time segments, an older one extending from the developments at Bingham in the early 1900s through the Second World War, ending about 1950; the second period extends from that time to the present. This separation is seen in Figure 1, which traces numbers of publications through the period as extracted from some 700 publications, again with a North American bias, from an annotated bibliography of porphyry copper geology in preparation. During the early period, exploration was "immature" in North America, that is, geologists looked for new districts and sites of the deposits. Outcrops were sought that carried the signatures of former mineralization and regional controls related to structural geology were closely studied. In the later period, North American exploration had "matured" into a study of districts, rather than a search for them. As the studies of these ores intensified during the younger period concommitant with increasing demands for the metal, they did so with a broadened understanding of some habits of occurrence, of hydrothermal alteration, mineral zoning, petrology, and geochemical and geophysical signatures. Outside of North America, search remained "immature" but closely related to the

Jan 1, 1997

By G. D. Naugle

Deep open-pit mines invariably affect the local and regional hydrologic systems. Pit dewatering, occurring during mining operations, puts an obvious hydrologic stress on these hydrologic systems. However, post-mining hydro-logic impacts resulting from the pit refilling with ground water following the cessation of mining activity can also be significant. Prediction of the rate at which the post-mining pit will fill with ground water is a critical aspect of assessing such long-term hydrologic impacts. Numerical ground-water flow modeling prov1des a method that can be used to predict the rate at which pits will fill with ground water.

Jan 1, 1992

At the dawn of the computer age in the early 1950's, few people in either the minerals industry or the field of electronic data processing (EDP) would have predicted the tremendous impact that the computer has had on the way we conduct our everyday lives and businesses. Herman Hollerith himself (see next page), the Columbia University mining engineer 'turned statistician who developed the first punched card electronic tabulating machines for the US Census Office in the late 1880's, would doubt- less be amazed at the progress that has been made in the application of data processing techniques to nearly all aspects of the mining cycle (Aul, 1974). More than any other factor, the availability of economical computing equipment has led the way for the development of the broad range of mining computer methods described in this text. While limits have been identified for many of the technologies commonly in use today, new technological advancements point to continued exponential advancements in computing price-performance in the 1980's. With those advancements, we may look forward to continued expansion of the role computers will play in mineral production.

Jan 1, 1979

By P. C. Schutte, A. J. Kielblock

INTRODUCTION Certain activities, such as emergency work and rescue operations, often have to be undertaken in environments where heat loads often exceed limits prescribed for routine work. This is particularly relevant to the South African mining industry where heat stress-induced fatalities are not uncommon during rescue operations. In this regard an excessively hot environment is defined as one where either the dry-bulb temperature exceeds 37,0°C or the wet-bulb temperature exceeds 32,5"C, and it is therefore not surprising that heat stroke mortality escalates rapidly when these limits are exceeded. A review of both local and international standards indicated that the available information on safe exposure times under abnormal heat stress conditions is very limited. Where available, such standards are aimed at the general population, including both sexes, irrespective of age and also the least heat tolerant worker, and not at a medically-screened, all-male population free of grossly heat intolerant individuals, as is the case in the South African mining industry. It is suggested that available norms and limits are too conservative for local application and, therefore, unrealistic. In view of the definite need to protect workers when exposed to abnormally high environmental temperatures, the present study was undertaken to establish a scientifically derived data base. applicable to local conditions, to determine safe exposure times: Any exposure limit, especially in an emergency situation, should be easy to administer, valid and reliable. These aspects, there- fore, form an integral part of this paper. FORMULATION OF HEAT STRESS LIMITS The formulation of heat stress limits was based on the criterion that a heat exposed individual should experience a negligible risk of developing dangerously elevated body temperatures. In order to provide a database for risk assessment, certain physiological responses of heat tolerant men were determined at various combinations of thermal conditions and work rate in a climatic chamber. These physiological responses were analysed statistically in order to predict safe survival and tolerance times as a function of thermal conditions and work rate. EXPERIMENTAL DESIGN A total of 202 randomly selected, medically fit mine workers volunteered for the study on the basis of informed consent. These men were considered to be inherently heat tolerant in as far as they had successfully completed a heat tolerance test (Anon., 1991) or the standard climatic room acclimatisation procedure used on many South African gold mines (Anon., 1989). The subjects were allocated randomly to 14 experimental groups and each group was exposed in a climatic room to one of

Jan 1, 1997

By M. M. Champion

INTRODUCTION Since the first introduction of explosives into mining operations, safety considerations have prohibited the use of machinery in association with the explosives. Only within the last 25 years has this situation changed appre¬ciably; the closest thing to "machinery" used by a powderman in the "old days" was his wooden tamping stick. With the blackpowder and dynamite used during the first 150 or so years of mining blasts, substituting a drill steel or a metal "spoon" invited serious disaster. With the advent of ammonium nitrate-fuel oil (ANFO) explosives (1950s) and water-gel explosives (1970s) for underground blasting, machinery started to play a large part in blasting procedures. The lower sensitivity of ANFO and water gels allows these prod¬ucts to be loaded in a variety of safe ways. Not only has this meant cost savings in labor and blasting materials, but it has also resulted in whole new mining concepts where the limitations of dynamite previously made those concepts uneconomical, impossible, or excessively risky. Increasingly (totally for some mines), the traditional tamping stick has given way to a variety of pneumatic machines for loading explosives and blasting agents. The resulting blasting operations have become safer, more efficient, less uncomfortable for personnel, and a major step forward in mining technology. ANFO LOADING EQUIPMENT Three basic types of loaders are used for ANFO explosives, these being the pressure-vessel loaders, Venturi loaders, and combination loaders. Pressure-Vessel ANFO Loaders ANFO consists of prilled ammonium nitrate (porous pellets I to 2 mm in diam) and fuel oil in the appro¬priate 94 to 6% blend. The material is fairly dry, pourable, and easily conveyed by an air stream. One device or system for handling (hole loading) ANFO is the pressure-vessel loader. ANFO is dumped into the vessel or "pot," and the vessel then is pres¬surized. The ANFO is conveyed out of the bottom of the vessel into a semiconductive hose that has been inserted into the blasthole. Fig. 1 illustrates a typical pressure-vessel loader in use. Applications: The use of pressure-vessel loaders is widespread in room-and-pillar mines, including salt, potash, trona, lead, and other rubber-tired mines where the heavy pressure vessels can be mounted on a vehicle for transport from face to face. The vessel often is large enough to hold eight or more 23-kg (50-1b) bags of ANFO, so several faces can be loaded before refilling. Pressure-vessel loaders also are suitable for effec¬tively loading long holes such as those that are 6 m (20

Jan 1, 1982

By T. Resende, J. Sismour

"Signs in underground mines are subject to variable airflow, which carries dust and moisture. Dust buildup reduces their visibility, hampering production efficiency and safety. Underground workers commonly must stop to clean signs in order to gauge their location, or find critical supplies or services. There are currently a variety of coating products, including dust and water repellants, available on the market that have the potential to reduce dust accumulation on sign surfaces. This paper describes a preliminary study to determine their effectiveness. The study involved a practical testing protocol using a trickle rock duster and samples cut from a clean, used road sign. Product effectiveness, under both dry and wet conditions, was evaluated based on photographic evidence by comparing changes in sign luminosity after a period of rock dust application. By analyzing the frequency of different pixel luminosities on the dust-covered samples, both uniformity of dust coverage and the total amount of accumulation was assessed. Results indicate that at least one product may reduce the amount of dust buildup on sign surfaces and increase visibility. INTRODUCTION In all underground mines, visibility of signage is critical. Signs inform miners of their location, direction toward escape routes, and location of supplies. Over time, sign surfaces can collect dust and can eventually become unreadable. The rate of dust accumulation on surfaces is often particularly high in coal mines, where both mining (e.g., cutting and drilling) and rock dusting activities can contribute significant amounts of dust to the airways. Several factors may contribute to dust buildup on sign surfaces. First, basic principles of fluid and particle flow are at play. When a fluid travels past a stationary surface, the velocity of the fluid at the surface boundary is zero. If a very small dust particle moving with air collides with a surface, it does not immediately fall off since the air velocity is zero at the sign surface. (This is the same reason that dust can collect on a rotating ceiling fan.) Further, once the collision occurs, other mechanisms may help keep the particle there – including friction that resists particle falling due to gravity, and adhesive forces due to humidity and/or static charges the particle and others already on the surface. Currently, the most common way to deal with reduced sign visibility due to dust buildup is for mine personnel (e.g., a compliance foreman, supply worker) to periodically clean sign surfaces – usually just by wiping them with a cloth. As a regular activity, this solution is inefficient; in cases of emergencies, it can also pose unnecessary risks. Application of an off-the-shelf coating to sign surfaces may represent a simple yet effective way to reduce the rate of dust accumulation. There are currently a variety of products on the market that may be suitable for this purpose, including dust and water repellants."

Jan 1, 2017

By K. Cothern, S. Novack, D. A. Johnson, R. Borden, S. Pavlou

A procedure is presented for ranking hazardous waste sites for remedial decisions, and an example with application to mining waste sites is discussed. Typical contaminant concentrations are calculated from field data. Exposure indices that compare these measured concentrations with allowable limits are then computed. The limits are selected to protect both the health of humans (for both carcinogen and noncarcinogen effects) and the health of key organisms in the ecological food web. The additive exposure index for a site, defined as the sum of all contaminant-specific exposure indices, is then used in ranking the sites and assigning each a priority for remedial action. One key source of uncertainty in the process is the estimation of a typical site concentration from data that include values reported as "below certified reporting limit" (BCRL). This uncertainty is compounded in the additive exposure index and therefore may have a substantial effect on the assignment of remediation priority. A general approach is presented for incorporating consideration of BCRL data into uncertainty evaluation when assigning remediation priority designators to hazardous waste sites.

Jan 1, 1992

By Richard Meriwether Smith

Mining-related earthy bodies in contact with the atmosphere are now counted, generally, as minesoils. Because soils within this broad category are extremely young the influence of parent material is stronger than in older soils, where climate, organisms, and topography have had time to interact with near-surface rocks to form more distinctly differentiated profiles. Understanding of minesoil properties and processes is aided by definitions of rock types in terms of chemical, physical, and mineralogical characteristics that are, with some degree of consistency, translatable into soils. Geological correlations based on age or sedimentary sequences are helpful if they assure details of mineralogy and lithology, but our pedologic objectives demand that any conflicts involving rock types must be resolved in favor of distinctions having strongest implications for soil properties after mining. Chemically this approach emphasizes accounting of potential acid-base status, plant nutrient availability by adapted and calibrated extraction procedures, and absence of biotoxins. Physically it anticipates particle sizes, shapes, and arrangements in readily pervious soil profiles that will favor plant growth with desired levels of moisture and oxygen. Concurrently we are considering soil property suitability for uses other than growth of plants. Above all we need to be able to predict pedogenic processes in the particular environment, including rate as well as direction of chemical and physical change.

Jan 1, 1974

By Michael J. Martinson

Mine ventilation has been evolving as a separate field of study since the middle of the nineteenth century, and some practitioners might assert that mine ventilation has come of age as a discrete field in the last decade or two. Certainly the extensive literature now available on many facets of the subject, international congresses, the phenomenal upsurge of interest in mine ventilation in the United States of America since the passage of the 1969 Federal Coal Mine Health and Safety Act, and the existence of a virile mine ventilation society in South Africa with its own monthly journal all point in this general direction; on the other hand the lack of a rational design philosophy for ventilating mines suggests that mine ventilation may still be on the threshold of maturity. To generalise, many mines are still ventilated simply to comply with arbitrary statutory regulations, or with some ill- defined notion of reducing the risk of injury associated with the atmospheric environment in mines. Hazards in this category include oxygen deficiency, toxic gases and particulates, pathogenic gases and aerosols, explosive gases and dusts, and extreme climatic conditions. Although many mines are ventilated to abate the risk of a specific injury, there is inevitably a spectrum of latent and patent atmospheric hazards in every underground mine. The writer (Martinson, 1976) has previously drawn attention to the dearth of material on mine ventilation design in textbooks and technical journals, and to the overly simplistic approach sometimes adopted in the limited work published on the subject. The available material undoubtedly contains useful technical data and persuasive views, but seemingly could not be used to demonstrate the rational engineering approach to mine ventilation design advocated in the present paper. The range of papers presented at the 1975 and 1979 Congresses, and the diverse interests and affiliations of delegates, emphasize the multidisciplinary nature of mine ventilation. Easily recognisable topics include: Fluid mechanics Thermodynamics Heat transfer Flames and combustion Aerosol physics Radiation physics Geophysics and geomechanics Occupational diseases Epidemiology Industrial physiology Despite these heterogeneous connections there can be little doubt that mine ventilation is fundamentally an engineering field and not an off-shoot of some other branch of applied science. The distinction is important because mine ventilation has essentially developed as a form of ad hoc trouble- shooting, and in the process mining engineers have relied extensively on the assistance of experts drawn from other fields. Thus historically there has been limited scope for the application of rational design techniques, and personnel enlisted from scientific disciplines may not have had any previous experience in the intricacies of engineering design.

Jan 1, 1980

By Jack Parker

Cycles of mine convergence coincide with annual cycles of temperature and humidity in the mine. Laboratory measurements confirm that the presence of moisture reduces rock strength and induces internal rock stress. Findings are used in the design of mine openings.

Jan 1, 1969

By W. C. Brice

Minnesota's mineral resources are widespread and diverse (Figure 1). In addition to the nation's largest iron and manganese reserves, the state contains sizeable vanadium, copper, and nickel resources. Recently it has been determined that the proterozoic unconformities in Minnesota have a favorable potential for uranium deposits. Finally, major potential exists in Minnesota's archean greenstone belts for gold, silver, and copper-zinc massive sulfides. Many of the state's mineral resources have been found in environmentally sensitive areas. This is not surprising since the natural forces associated with the formation of mineral deposits are often the same processes that create unusual landforms. For example, much of the state's copper-nickel is found within and adjoining the Boundary Waters Canoe Area (BWCA) and Lake Superior. The history of mineral development on the Mesabi Iron Range has also created culturally sensitive areas. Early iron mining development required the workers to live close to their jobs, and mine wastes were dumped as near the mine as possible. Few, if any, foresaw the time when taconite would be economic to mine. Therefore, it is not unusual to find valuable taconite resources located under towns and waste dumps on the Mesabi Iron Range.

Jan 1, 1980

This paper summarizes the process development behind the design of three different types of paste fill plants at operating Canadian hard rock mines. Each application has a unique paste backfill mix and process which utilizes the materials economically available to the mine site. The different plants produce paste fill composed of base metal tailings, a blend of recovered disposal pond tailings fines and alluvial sand, gold ore tailings, and a blend of gold ore tailings and alluvial sand. This work has led to the joint development by Inco and GL&V Ontario of the compaction storage mechanism for the de-watering of mill tailings to a paste consistency.

Jan 1, 1994

Caterpillar recently held two, two-day demonstration programs for its mining customers. The event, billed as MineDemo by Caterpillar, consisted of two sessions held on consecutive weeks at the company's Tinaja Hills proving ground south of Tucson, AZ. The program included several classroom sessions that focused on Caterpillar equipment applications, including the VIMS (vital information management system) and the CAES (computer-aided earthmoving system). Also included were field demonstrations and the opportunity to test drive mining-related heavy equipment, including dozers, trucks, graders, shovels and loaders. Featured at the event were the recently upgraded 785, 789 and 793 C-Series trucks. Caterpillar recently announced the availability of the 136-t (150-st) 785C and the 177-t (195-st) 789C. The upgraded haulers have replaced the respective B-Series models. The 218-t (240-st) 793C was introduced in 1996. It, too, has been upgraded but retains the C-Series designation. While attending the press event, the author had the opportunity to test drive the 793C at the Tinaja Hills test site. It was amazing how well the machine handled. The operation was smooth and the braking system was precise. The cab was extremely comfortable. To see a C-Series truck in action, the author also visited Newmont Mining's Mesquite Mine, located in Cali¬fornia, across the border from Yuma, AZ. The Mesquite Mine operates a new model 785C truck. At the mine, temperatures have been measured as high as 58° C (138° F) in the pit. Needless to say, the ability to operate dependably in extreme heat is an important consideration for the mine operators. An interview with the driver and later with management confirmed that the 785C has worked out well. The driver praised the comfort of the cab and the ease of operation. Management reported significant fuel savings and was impressed by the truck's maintenance features.

Jan 1, 1999

By H. R. Thompson

The Grant Town Power Plant is a nominal 80 MW (net) Waste Coal-Fired Electric Generating Plant which is located in northern West Virginia, approximately 15 miles southwest of Morgantown. The Steam Generator consists of two (2) Pyro-Power Circulating Fluidized-Bed Boilers (CFB), each rated at 400 000 lbs/hour @ 1,350 psig. Main Steam. The Turbine Generator is a single GEC Ahlstrom unit rated at 95 MW gross and 80 MW net. The Plant began commercial generation during April, 1993. The facility is owned by American Bituminous Power Partners, L.P. (AmBit), and operated by Mission Operations and Maintenance, Inc.

Jan 1, 1996

By Stephen G. Hardcastle

3D-CANVENT is a software package that integrates advanced computer aided design (ACRD) true 3D graphics with a mine ventilation simulator. The package runs as a Windows(tm) application to access its printer drivers environment and does not need third party CAD software. It is composed of two primary modules: DMVENT and MINEDESIGNER. DMVENT is a traditional Fortran coded Hardy-Cross iterative ventilation network solver written in 1980 with thermodynamic capabilities. This module is relatively unchanged with the traditional data input options for branch type, specified or calculated resistances, fixed flows, and fixed or variable pressure fans. MINEDESIGNER is the graphics engine that optimizes the ventilation design process. It performs the front-end transformation of input data entered in the graphical interface into the correct format for the solver. At the back-end it reconverts the historically standard tabular data output from the solver into an easily viewed graphical format. ACRD features of MINEDESIGNER are used to generate a 3D wire-frame node and branch network of the mine's ventilation system. The network can be displayed in up to 4 views orientated to XYZ planes or a 3D view. All the views have zoom, pan, slice and rotate options. The graphical interface efficiently permits data entry and editing via a mouse with pick-and-point item selection. Branches can be found or added with "search" and "join" options. Visual interpretation is enhanced by the 16 colour options for branches and numerous graphical attributes. Network locations are readily identified by alpha-numeric names for branches, junctions and fans, and also the logical numbering of junctions. The program is also readily expandable for pollutant simulation and control/monitoring applications.

Jan 1, 1995