Search Documents

By J. C. Watts

Ball mill grinding circuit control has received increasing emphasis in the past few years due to such factors as declining ore grades, increasing production costs, and advances in analytical devices and minicomputer technology. Since ball mill circuits have been a traditional bottleneck in mineral processing plant throughput, control systems often improve through- put without requiring additional processing equipment. In addition, much of the variability of the grinding product size and consistency is often removed, allowing better process operation downstream. Among the problems which arise in designing and implementing a process control strategy for ball mill circuits are circuit constraints imposed by processing equipment and local management, proper instrument selection, installation and maintenance, and use of calculated or inferred variables for process measurements. This paper discusses these problems and attempts to identify valid approaches to their solution.

Jan 1, 1979

By R. J. Hickson

From 1993 through 1999, Cyprus Amax Minerals successfully completed eight major construction projects around the world. Six greenfield mines were brought into production, an ongoing operation was completely modernized and an environmental issue was appropriately remediated. The projects stretched over three continents: from arctic Russia to the Atacama Desert, from sea level to an elevation of 4,900 m (16,00Oft), from city suburbs to remote wilderness and from a low of US$130 million to more than US$ 1billion. The operations included open-pit and underground mines, mill and leach facilities and involved gold, copper, molybdenum and coal. The diversity of these projects inspired Cyprus Amax to create a "best-practices” project-management protocol to steer corporate expansion in the new millennium. This paper summarizes these best practices, while highlighting the project-management pirfalls to avoid.

Jan 1, 2000

By Nenad Spoljaric

Greensand, greensand marl, and green earth are names given to sediments rich in the bluish green to greenish black mineral known as glauconite. The word glauconite is derived from the Greek word glaukos, meaning bluish green. The term "greensand" as a rock name for a glauconite-bearing sediment is more appropriate than "greensand marl," a term that has been doggedly perpetuated in the literature. Because of its potash and phosphate content, greensand was mined and marketed as a natural fertilizer and soil conditioner for more than 100 years. The advent of manufactured fertilizers with adjustable nutrient ratios led to a decline in the use of greensand in agriculture. The material has since been recognized as useful in water treatment. Unfortunately, despite large reserves and world- wide distribution, glauconite has not been utilized to any significant commercial extent because no major application has been found for a substance with its chemical composition and properties. This is probably due mostly to a paucity of research on its potential commercial uses. Extraction of potash received considerable attention during and just after World War I. Because of relatively high extraction costs and a generally low potash content (viz., less than 8%), glauconite lost its appeal as a source of this commodity. Historical Background Greensand was used as a fertilizer in New Jersey in the latter part of the 1700s. During the early 1800s its use became more common; applications of as much as 22.5 kg/m2 were sometimes made, although recommendations for agricultural use suggested 4.5 to 11 kg/m2 (Tedrow, 1957). Many crops, especially the forage type, were said to improve with greensand application; however, because of its slow release of potash, large quantities were required. Certain greensands that contain sulfur and sulfide minerals are harmful to plant growth, and these were classified as poison, burning, or black marls. The availability of higher grade potash salts from other mineral sources and the manufacture of prepared fertilizers displaced the agricultural use of greensand during the latter 1800s. During the mid-1800s the greensand industry, centered in a small section of the eastern United States, grossed more than $500,000/y. Toward the end of the century, however, annual production had dwindled to less than $100,000 in value. By 19 10 there were only six or eight greensand producers grossing less than $5,000/y each (Tyler, 1934). There was a brief revival of the US industry during World War I because of the curtailment of foreign potash, especially from Germany. During the latter 1940s and early 1950s greensand was again recommended as a food nutrient for plants and farm crops. Agronomic studies discussed its potential as a soil additive that gradually releases potash and many trace element nutrients essential for plant growth (Tedrow, 1957). Greensand was sold with the idea that it would condition soil and absorb and hold water while its base exchange properties would release trace elements. For a short time glauconite was used in certain parts of New Jersey as a binding additive in the brick industry, and in the 1800s it was used for making green glass (Cook, 1868). In the early 1900s the base exchange properties of glauconite were recognized for water treatment and the mineral gained acceptance as a water softener. Mansfield (1922) does not mention base exchange even though this phenomenon was known in 1916 or earlier. From 1916 through 1922 several patents for the use of glauconite as a water softening agent were granted. A method was also patented for treating greensand to improve it for water softening and ready regeneration with common sodium chloride brine (Borrowman, 1920, Spencer, 1924, Kriegsheim and Vaughan, 1930). Treated glauconite, on contact with water containing magnesia or lime, takes up magnesium or calcium ions and releases sodium ions. This exchange is limited to the outer surface of glauconite grains, and when all the surfaces have absorbed their capacity, the grains must be regenerated. Regeneration, simply stated, consists of treating or backwashing the glauconite with a sodium chloride solution, which replaces the hard water elements with sodium, thus reviving the glauconite. The process has become more sophisticated due to competition among companies in the water softening business. Greensand products for water softening generally consisted of several different grades distinguished by the particular treatment the glauconite was given during processing. The standard greensand water softener was produced from natural glauconite that was only washed and classified. Its characteristics for water softening are given in [Table 1].

Jan 1, 1994

By V. W. Skema, M. W. Smith

Pennsylvania has 4,000 km (2,500 miles) of streams that do not meet water-quality standards due to acid mine drainage (AMD), making AMD the greatest cause of water pollution in the state. The problem is mainly caused by abandoned coal mines. To abate AMD, Pennsylvania is using a watershed-based approach that includes remining as a key component of a comprehensive restoration strategy. The Tangascootack Creek Water-shed was targeted for AMD restoration through remining. Geologic mapping and overburden data were analyzed using Earth Vision software to identify areas of coal reserves that could be remined to improve water quality. Incentives are offered to encourage mining in these designated areas.

Jan 1, 2002

By T. A. P. Sankar, S. Gundiah, Pradip, R. A. Kulkarni

Two modified polyacrylamide flocculants, namely polyacrylamide with glycolic acid functionality (PAMG), and a copolymer of acrylamide with N-acryloyl-[T]- aminobutyric acid (HPVP), were synthesized, characterised and evaluated for selective separation in apatite/quartz and apatite/dolomite/calcite systems, respectively. PAMG flocculant was found selective in the separation of tricalcium phosphate (TCP) from its mixtures with quartz at acidic to neutral pH range. The selectivity deteriorated at alkaline pH. In contrast, polyacrylic acid (PAA) flocculant was found most effective only in the alkaline pH range. HPVP flocculant (even though flocculating all three minerals namely apatite, dolomite and calcite) was observed to be quite selective for the separation of calcite from apatite-dolomite minerals in single mineral tests in the presence of sodium hexametaphosphate dispersant at neutral pH. There was, however, no selectivity observed during tests on synthetic mixtures. This loss in selectivity is attributed to the phenomenon of hetero-flocculation, as reported earlier, for separation in an apatite-dolomite system with polyethylene oxide.

Jan 1, 1993

By Omar A. Muhtadi, R. Bruce Thorndycraft, David A. Milligan

9.1 INTRODUCTION Precious metals in a leach solution are extracted, concentrated, and purified to complete the process begun in the heap and to produce an end product which will provide an economic payback to the mine developer/operator. Several different processes are required to convert the dissolved precious metals into pure metal bars. This chapter discusses the actual production of metal once it has been recovered from the pregnant leach solutions by the zinc cementation (Merrill -Crowe) or carbon adsorption processes. Metal production is generally taken to mean the production of a fairly pure "dore" bar. This chapter also reiterates some information from Chapter 8 in a slightly different context, since the focus of Chapter 8 was a fairly detailed description of the two actual recovery processes, whereas the focus of this chapter is metal production. The sale of an intermediate precious metal product is possible (as opposed to the production of dore bars at the mine site); however, the value of the precious metals is reduced by the various charges and risks associated with precious metal processing. For this reason, most operators choose to produce the most refined metal possible in order to maximize project economics. Precious metals may be extracted from the leach solution by both conventional and unconventional processes. The conventional processes are activated carbon/electrowinning (ACE) and zinc precipitation (ZIP). The unconventional processes are resin ion exchange, solvent extraction, and direct electrowinning. A typical ACE process has two circulating loops. The first loop adsorbs the cyanide-metal complexes from the dilute leach solution onto the activated carbon. A second, separate solution loop removes the cyanide-metal complexes from the activated carbon into a strong solution, the electrowinning electrolyte. Activated carbon is transferred from one fluid loop to the other. The operating cost of the ACE process is directly proportional to the quantity of carbon stripped and thus to the quantity of precious metal produced. A typical ZIP process contains a single circulating loop. The solution is filtered, deaerated, contacted with zinc, and filtered again. The barren leach solution is then returned to the heap. The zinc sludge recovered in the

Jan 1, 1988

By H. C. Verakis, T. E. Lobb

During the past decade, approximately 5 billion pounds of explosives were used annually in the United States. Most of this quantity of explosives was used by the mining industry, with coalmining being the dominant application for explosives. Considering the large amount of explosives used, the accident safety record for the mining industry has improved significantly over the past several decades. Although blasting accidents usually represent a small percentage of the total number of mining accidents, they continue to occur and the severity of these accidents is disproportionately high compared to the other mining accidents. This paper is an analysis and summary of mine blasting accidents over the past several decades as they relate to surface coal mine operations. A compilation and review of surface mine blasting accidents from1978 through 2001 was made. The accident data was examined to identify the trends and primary causes, which continue to be blast area security, fly rock, premature blast, and misfires. Approximately 46percent of the causes of surface coal mine blasting accidents are attributed to blast area security, while fly rock, premature blast, and misfires represented an additional 50 percent of the causes. Accident categories were established based on the cause of the accident or the activity that was taking place when the accident happened. A discussion of the accident data is presented to increase hazard awareness and to emphasize safe blasting practices and MSHA requirements concerning mine blasting operations.

Jan 1, 2003

By Murray Malott

The Sheppard Subway extension is currently being constructed in Toronto, Canada for the Toronto Transit Commission (TTC). McNally International Inc., in a joint venture with PCL and the Foundation Company of Canada were awarded the Twin Tunnels contract of the Sheppard extension. The Twin Tunnels project is approximately 4.4 km in length and consists of two separate twin bore drives each 3.3 km and 650 m in length and approximately 400 m of cut and cover construction. This paper presents a case history of the construction of the soft ground tunnels through the complex Toronto glacial deposits using two 5.9 m outside diameter Lovat earth pressure balance (EPB) tunnel boring machines.

Jan 1, 1999

By James C. Burrows, Frances Kramer Mesher

Tungsten-containing ores are mined on all continents of the world. China is the world's largest producer and controls the world's largest reserves. The USSR, itself a sizeable producer, is estimated to be the world's largest consumer. The major use for tungsten in the noncommunist world is in production of cemented tungsten carbides for cutting, drilling, and wear parts. Other major uses include lamp wires, steels for tools, and armaments. Real tungsten prices have been in a general decline since 1977-1979 as the tungsten market undergoes basic and lasting structural changes.

Jan 1, 1986

By Gerald V. Jergensen, Edward J. Samuel

Slurry system are the principal method for storage and transportation of solids within and between concentration operations In a mineral processing plant. A slurry 1s a mixture of solid particles In water, or a chemical solution, that behaves like a liquid. The design of slurry transportation systems is generally analagous to pumping and piping water, but with a few notable exceptions: • The interaction of particle on particle affects slurry transport. • Particles often interact with the fluid, particularly when chemicals have been added to the system. • Particles have a frustrating tendency to settle from the slurry suspension, especially into locations not considered In the design. • Solids have an affinity for wetted surf aces and tend to wear them away. Slurry transportation systems Include a number of separate components, each requiring special design considerations. A systematic evaluation of each component of a slurry transfer system will help overlooking the small details that could cause operational headaches. Most slurry transport systems include: • A receiving sump or tank that provides for mixing and/or momentary storage of slurry. • A driving force.. by a pump, atmospheric pressure or gravity. • A suitable conduit for transportation.. pipes or launders. • A delivery objective.. another sump or process vessel, or distribution system to several process points. • A control strategy and design to regulate the transfer operation. The design of the slurry transportation system normally evolves through the following steps: • Finalizing the process flowsheet and establishing the weights and volumes to be handled. • Identifying and characterizing the various process fluids and slurries. • Defining critical and minimum transport velocities of fluids. • Selecting a pipe diameter (or dimensions and gradient) and

Jan 1, 1986

Some basic terms used in cost management and accounting include: - Cost. A sacrifice made to acquire goods or services, measured by the price paid. Technically, the sacrifice is called a cost until the benefits from the goods or services have expired, at which time the sacrifice is called an expense. In this text, the terms "cost" and "expense" are used interchangeably. - Revenue. An increase in the value of the firm resulting from the sales of goods and services. - Income. The excess of revenues over costs for a specified period. The term is often used with modifiers to indicate specific quantities on an income statement (e.g., pretax income; net income). - Activity. A measure of production work. Traditionally, physical production volume (tons of ore or units of product) has been used as the measure of activity. Other measures include direct labor hours, equipment operating hours, and quantity of materials or supplies consumed. - Responsibility center. A segment of an organization that is responsible for a specified set of activities. In mining, individual operating divisions can be treated as responsibility centers, known as profit or cost centers. Departments within a division are generally treated as cost centers. - Cost center. A portion of an organization having responsibility for achieving specified levels of cost. - Profit center. A portion of an organization having responsibility for achieving specified levels of profit (revenues and costs).

Jan 1, 1999

By K. Fotoohi

This paper presents a basic, and yet practical, three-dimensional finite element model that was developed by the authors for stress/stability analysis of mine structures. While the code is linear elastic at this stage, it has some practical features that make it an attractive tool for mine design. Such features include: simulation of mine backfill support, mining induced strain energy calculation, powerful out-of-core frontal solver and failure analysis by Mohr-Coulomb or Hoek-Brown failure criteria. Model development criteria are discussed, and the potential application of the model to mining is demonstrated by design examples.

Jan 1, 1998

By John W. Ahlrichs, E. Daniel Baker, Erich U. Petersen, William J. Tafuri, Douglas N. Halbe

The combined Bootstrap and Capstone deposits, located in the Bootstrap subdistrict (Section 10, T36N, R49E, M.D.B.M., Elko County, Nevada), are approximately 27 miles northwest of Ca-1I: Nevada. The contiguous Bootstrap Capstone deposits are located along the northeastern and northern flanks of Round Mountain, a horst block separated by grabens from the sheep Creek Mountains to the north-northwest and the Tuscarora Mountains to the east. Open-pit-minable gold reserves as of December, 1989, were 13.27 million short tons with an average grade of .057 troy ounces gold per ton and an overall waste-to-ore strip ratio of 2.5:1. Ore zones in Bootstrap are concentrated along north striking high-angle dikes localized along faults, while ore zones at Capstone are strata form and structural, occurring at the Devonian limestone/siliceous sediment interface and in high-angle fault-filling dikes. Pre-ore faulting produced a complex structural setting for Capstone, dominated by strong northwest fault sets cross-cut by northeasterly structures. Alteration associated with both deposits is silicification with a-strong argillic overprint. Dike emplacement, which post-dates silicification, marked the onset of mainstage gold deposition and argillic overprinting of silicified lithologies. Gold displays an affinity for moderately argillized sedimentary and igneous lithologies. Mineralogic and geochemical analyses of rotary percussion drill samples show good correlation between gold, silica, antimony, and arsenic.

Jan 1, 1990

By F. F. Aplan

Prologue Antoine Marc Gaudin (Fig. 1) was truly a giant in the field of mineral processing, and his shadow is still cast long on our profession. "Tony," as his students affectionately called him (but never to his face), came to the United States in 1917 and enrolled at Columbia University where he studied under Professor Arthur F. Taggart. Later, as a lecturer, he wrote his classic comminution paper (Gaudin, 1926). This important work led to his appointment as an associate professor at The University of Utah, where he conducted highly original work on flotation fundamentals that is still widely quoted today (Gaudin et al., 1928-30). In 1929, he was appointed Research Professor of Ore Dressing at the Montana School of Mines in Butte. Shortly thereafter, he published his first book, Flotation (Gaudin, 1932). Because Gaudin could so quickly cut through the fog to get to the essence of a problem, this is still a valuable reference book. It is a valued part of my personal library, and I consult it frequently. Over the next decade, he conducted an outstanding graduate research program at Butte, but, more importantly, he honed his undergraduate lectures and produced the century's outstanding text in the field, Elements of Mineral Dressing (Gaudin, 1939). More than 50 years later, this terse book is still found to contain most of the elements of the discipline. Its sections on the

Jan 1, 1994

By H. Beecher (Original by) Charmbury

Water is a most remarkable substance, essential for life of all kinds. As well as needing water to survive, man has always used it for agriculture, transportation, recreation, and many other things. When our country was young and inhabited by few people, the streams, rivers, and lakes were able to provide all the clean water needed by man and take away all the wastes created. However, with our growing population and an ever-increasing demand for goods and services, the public, industry, and government at all levels have become acutely aware of the need to manage the nation's water resources more efficiently. Abundant energy from many sources has helped this nation to become the greatest industrial nation in the world. Coal has contributed a major portion of this energy, generating electricity, running railroads, and maintaining national security during wartime. The result has been the highest standard of living in the world and a time of widespread economic prosperity. The use of water in coal mining is somewhat different from its use in most industries. With the exception of water used in cleaning plants, for underground dust control, and for fire protection, most of the water en- countered in coal mining operations serves no useful purpose. In other words, it is an undesirable element and must be removed, otherwise it will interfere with operations, cause potential water quality problems, and may even stop operations by flooding. In the past, removing water from working areas of most mines was usually a fairly simple matter. Pumps with piping were installed at sumps or low spots in the mine and the water was pumped to the surface or to drainage control facilities constructed for the operation. Ditches were often used to collect and drain the water by gravity to the outside or to main sumps for pump discharge. In either case, the water was allowed to flow into the nearest stream or river. The concept of "water is water' was generally accepted without too much concern for what was in the water since low-cost products and services, rather than clean water, were the public demand.

Jan 1, 1981

By Thomas H. Koenning, William E. Bruce

The importance and complexity of the ventilation systems in many underground coal mines necessitates the use of digital computers to model the ventilation networks. The modeling procedures used by the Mine Safety and Health Administration (MSHA) utilize the MSHA-modified Penn State computer program. The basic techniques used by MSHA have been described in detail in NESA (now MSHA) Informational Reports 1066 and 1183 (1. 2). Two basic methods are utilized for modeling underground mine ventilation systems. The first modeling method is the use of actual air-flow, pressure, and fan-performance data acquired during a full air-pressure, air-quantity ventilation survey to develop a mathematical model of the ventilation system. The second modeling method is the design of a ventilation system using data obtained from calculation, from past experience, or from technical literature. The latter method would typically be used to design a ventilation network prior to developing a new mine. Regardless of which method is used for modeling, there is a need to know, or to calculate, appropriate resistance values to be used for airways and for the various ventilation control structures. Such data is typically difficult to obtain and this report is an attempt to summarize typical resistance values which may be used in designing ventilation networks for new mines or in simulating proposed system changes in existing mines. Illustrations are presented to show where some of the resistances typically are located and how they are modeled in mine ventilation net- works.

Jan 1, 1987

By R. L. McNearny, K. A. Barker

Four numerical models written with the "PFC2D " program were compared against four similar physical models. The numerical models were constrained numerically to closely follow the caving behavior of the physical models. Results from the numerical analyses closely simulated both the granular and blocky behaviors of the physical models, including bridging and interlocking of the simulated orebody during draw. The drawdown patterns and the rate of draw developed during numerical modeling also closely simulated the physical models. The same assumptions and governing parameters used in analyzing the first four models were applied to an additional model. The fifth model employed a completely different, uneven, draw sequence than the other four models, allowing the material to flow in a more granular manner with a demonstrated instability of the undercut sections between each drawpoint opening. Drawdown patterns and behavior of the numerical material of the first four models progressed at uneven and inconsistent rates, similar to those seen in the physical models. By inspection, the overall shape and flow lines of both the numerical and physical models were close in the area removed and in the flow characteristics. The fifth model proved to be the most unstable of all the models tested, with poor correlation to the physical models. The uneven draw sequence, coupled with an additional frictionless wall condition and an added drawpoint, caused the material to flow in a very granular manner. Information generated by this study can be used as a first approach in determining the proper draw rate, drawpoint spacing and undercut thickness for a block-caving operation. Numerical models are often difficult to predict and interpret. However, this study should increase the confidence level for use of the PFC2D program in the future.

Jan 1, 2000

By Rowan Melrose, Naj. I. Aziz, Arvind Misra

Mathematical models have been developed to simulate longwall heading development systems in Australian Longwall Mines. The models developed consider the effect of non concurrent cutting and supporting systems and concurrent cutting and supporting systems. They also consider the impact of operating parameters on each of these systems. Operating parameters that are considered include pillar dimensions, the use of surge cars, bolting time, shuttle car speed and heading advance per cycle. The effect of these parameters is considered with respect to production rates and also panel advance rates.

Jan 1, 1996

By K. S. Venkataraman

The physical properties of clay-water systems depend on the complicated system of forces between the clay particles themselves, and between the clay particles and the ions in the liquid phase. The kind and distribution of ions in, on, and between the clay particles and the size and the shape of the particles are the basic factors determining the macroscopic behavior of clay-water systems. Understanding the system requires a knowledge of the nature of the clay particles, their size, structure, composition, and surface properties, and of the manner in which they interact with ions [and molecules] in the surrounding liquid [or other medium]. The validity of Professor Brindley's words (Brindley, 1958), written three decades ago in the context of making pottery, whitewares, and electrical porcelains, transcends time, and the basic message is perhaps all the more important in the considerably expanded use of ceramics for structural, thermal, tribological, electronic, and other applications. Silicon carbide, silicon nitride, and sialons have been studied in the last two decades for high- temperature structural and tribological applications, particularly for using in internal combustion engines. Titanates, zirconates and niobates of barium, strontium and lead, have high dielectric constants, and are extensively used in the formulations for making capacitors. Hexagonal ferrites (molecular formula MO.6Fe2O3) are in use for making permanent magnets for fabricating miniature motors, and for assembling loud speakers, particle accelerators etc. Cubic ferrites such as magnesium-zinc ferrite and nickel-zinc ferrite are used as transformer cores, and for other high-frequency applications. In this context, Richerson's recent book (Richerson, 1984) on the general scope of traditional and technical ceramics is a good starting point for an overview of contemporary ceramics technology. Glasses are a whole class of amorphous materials used widely as sintering aids, and for making glass-bonded ceramics and glass-ceramic composites. Composites are yet another burgeoning field where two or more particulate components are used for improving the performance of ceramics. For all these applications, the inorganic starting materials are almost always submicron and near-micron powders. Understanding the powders' physicochemical properties, and their surface chemical interactions with the surrounding liquid/gaseous medium is-necessary for making reliable ceramic parts at competitive prices. Even though ceramics science and engineering has attained its separate identity in universities and the industry, ceramists themselves would concede that ceramics science is a cross-disciplinary field, having incorporated and assimilated within itself many principles from several apparently disjointed disciplines. Principles of material science, graduate-level physics and chemistry, polymer science, surface and colloid chemistry, transport phenomena, particle technology, unit operations commonly used in chemical engineering and mineral processing, and statistics and applied mathematics are integral part of any ceramics curriculum in universities. Added to this is the fact that all bench-scale successes in making ceramic parts are to be scaled-up for larger throughput operations. Understanding and applying process engineering principles of comminution, classification, drying, calcination, etc. then becomes essential. CERAMIC FORMING: Despite the diversity of the materials and processes, conceptually, the steps involved in making ceramic parts have remained the same over several decades: The different components for making the pan (usually one or more powders plus other forming and sintering additives) are proportioned and mixed thoroughly, and the well-mixed formulations are consolidated into desirable shapes known as "green bodies." Usually binders such as wax, clay, organic polymers and surfactants, whether dispersed or dissolved in a suitable liquid are used during mixing the batch for giving strength for the green bodies. In the dried green state, the inorganic powders typically occupy only 55 to 60% of the bulk volume of the body, depending on the particle size distributions of the powders and the forming history, with mostly inter- particle voids accounting for the rest of the void volume. SINTERING: The formed bodies are then fired in high- temperatures kilns/furnaces during which the parts are exposed to a predetermined temperature profile, and "soaked" for a certain duration at the final high temperatures, typically between 1200 K and 1900 K, and then cooled to room temperature. The gaseous atmosphere in the furnace is controlled (oxidizing, reducing, or inert) when necessary. During the initial stages of firing, volatile liquids evaporate, and during the intermediate temperatures between 400 and 600 K, the the organic polymeric additives pyrolize and oxidize into water vapor, CO, C02, and other gases. At still high temperature, the glasses, when present, soften, and simultaneously, the ceramic particles rearrange into a network of grains with definite grain boundaries so as to reduce the total interfacial free

Jan 1, 1990

By Walter Keune

Object Modeling Technique. This formal descriptive language makes it possible to formulate requirements in the real world in such a way that they can be implemented in the form of entities (cf. Entity Relationship Model[Che83]) and methods (see Figure 1). The object {Roadway} is graphically depicted by means of the Polygon method.

Jan 1, 1996