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By G. O. Kesse

The Republic of Ghana, located on the West Coast of Africa, is one of the West African countries rich in bauxite deposits. The main occurrences of bauxite deposits are at Sefwi Bekwai in the Western Region, Aya-Nyinahin in the Ashanti Region, Atewa Range near Kibi and at Mount Ejuanema both in the Eastern Region of Ghana. These bauxite deposits belong to the so-called blanket deposits as they are associated with erosion surfaces of old peneplains and occur as cappings on the flat tops of hills or mountains whose heights are generally greater than 600 metres above sea level. These deposits can also be classified as laterite-silicate bauxites since they have been formed under tropical weathering conditions. Genetic and mineralogical investigations have revealed that all bauxite deposits of Ghana are the result of indirect bauxitization processes, for the minerals of the weathering parent rocks have not been transformed directly into gibbsite. In all cases, lithomarge of kaolinitic clay can be recognised. The geology of the major occurrences of bauxite in Ghana shows that the Mount Ejuanema deposit is the only deposit associated with the Voltaian System of rocks. This rock System consists mainly of sandstone, shale, mudstone, conglomerates and pebbly beds. All the otter deposits are associated with the Birimian System of rocks which are made up of metamorphosed lavas,pyroclastic rocks, hypabyssal basic intrusives, phyllites, schists, tuffs and greywackes.

Jan 1, 1984

By Stanley M. Jarrett

Gentlemen, I am pleased to address this gathering of engineers and operation managers representing a large and important segment of the metal and nonmetallic mining industry. Since you know from the printed program that the theme of my paper is the furthering of safety in open pit mines, perhaps you will have guessed that I will also comment upon the image created in the public mind by the industry's safety record and the potential consequences thereof in national health and safety legislation. Operators of surface mines have some cause to congratulate themselves on the basis of figures issued by the national safety council which show that lost-time accidents per-million-man-hours in surface mining (11.18), is lower than that of all other mining. Moreover, the accident frequency in surface mining is only slightly above the median accident rate for all American industry (8.87). That is a good record.

Jan 1, 1972

In 2002 the authors updated the MFire model developed by the US Bureau of Mines. MineFire, developed by Mine Ventilation Services, Inc. (MVS), uses the MFire model to perform mine fire simulations on typical mine ventilation networks. The MineFire program is capable of producing visual schematics and other analysis tools for input and output of the MFire model. The MFire model, however, was limited to 500 branches and 10 fans. This paper discusses the newly modified MFire model that is now capable of modeling over 5000 branches and over 400 fans among other expansions and improvements. Given the long history and proven track record of MFire, the expansion did not modify the core calculation methods or results. This paper focuses on a general discussion of the MFire program and issues encountered in expansion of the algorithm. An example large network with simulation results is discussed.

Jan 1, 2011

By Barry Hunsaker

I cannot help but be reminded, as I stand here today, of my boyhood years and heritage, both of which are inextricably tied to this very valley and are, in a: bay, apropos of the theme of this Keynote Session. I remember the scarcity of people. For example, 48, 000 in Phoenix and 436, 000 in the State in 1930 and 65,000 in Phoenix and 499, 000 in the State in 1940. Today Phoenix boasts a population of over 500, 000 and the State a population of 1, 500,000. I remember the' lack of facilities, goods and services, including gas and electric power. I recall stories of my grandfather who had the freighting or teaming contract to haul all the supplies and generating equipment, by wagon mind you, up the old Apache Trail to Roosevelt Dam. . .a three day trip from the nearest railhead which, by the way, was not Phoenix, for it did not merit a railhead on those days, but the village of Maricopa approximately 25 miles south of Phoenix. I remember chopping firewood, heating wash water on an open fire in a No. 3 wash tub at the rear of the house and doing my school homework by the light of a kerosene lamp just 25 to 35 years ago within what is now a large metropolitan area

Jan 1, 1965

By Peter B. Dowden, David T. Cass

A shield on a tunneling machine has two basic purposes. Firstly to provide temporary support in unstable ground, maintaining the integrity of the bore and protecting the operators, and secondly, in conjunction with other sealing devices, to prevent the ingress of water. In any specific tunnel, unstable ground and water may or may not occur together. Further, there are a number of different ground behaviors that may be termed unstable and these must be defined in order to determine the most suitable type of machine. Beyond the shield itself, the cutterhead and the mucking system design are critical in successfully traversing difficult geology. In any but the shortest tunnels, variations in the geological conditions and the requirement of an acceptable advance rate can impose increasing degrees of sophistication in the machine design. In this paper we will review current designs of shielded type machines and their application, and discuss new developments which blend hard and soft ground tunneling technology. We will also indicate that in some conditions, although first impressions seem to favor a shielded machine, in fact an open gripper TBM may be the wisest choice.

Jan 1, 1991

By Shamsuz Zaman, Barry Hansen

The major development in the evolution of the conventional subaeration flotation machine has been the steady increase in the size of the individual units. In 1950, large machines were of 1.35 m3 (48 ft3) volume capacity. In 1989 the largest volume capacity operating is 85 m3 (3,000 ft3 ) These improvements have enabled the mining industry to operate successfully in the face of declining ore grades and adverse metal prices. This paper describes the design features and performance characteristics of a number of significant flotation machine designs.

Jan 1, 1989

By Kenneth K. Landes

So far my consulting in industrial minerals has been confined principally to carbonate rocks,-salt, coking coal, and glass sand. Much of this work has been for companies either too small for a full-time geological staff or unaware of the value of employing one or more qualified geologists permanently. It gave me considerable personal satisfaction to see several of the latter companies employ one or two full-time geologists after the completion of a consulting contract with them. One possible reason why some companies lack the wisdom to hire geologists is that they are dominated by engineers who still subscribe to the old idea that engineers are self-sufficient in all fields. They could have learned this from their professors. I once knew a Dean of Engineering who got purple in the face when a faculty committee was discussing the financing of a broad gauged engineering project and suggestions were made that assistance be obtained from the Schools of Business and Law and from some of the science departments tie pounded the table and shouted "Engineers are trained to handle all this!" In teaching engineering geology some years ago I used to tell the class repeatedly that the course would not make them geologists, that the purpose was to teach them

Jan 1, 1972

By Pat C. Hautala, J. R. Hoskins

This is a new era for the minerals industry. Never before has there been more need for effective communication. So said Robert Anderson, chairman and chief executive officer of Hanna Mining Co. He was speaking to the American Mining Congress's Communication Workshop. The question is whether there is enough industry concern to meet the challenge. Anderson observed that increased workshop attendance, in continuing tough times, reflects the industry's concern for communication. But, why were students, faculty, engineers, supervisors, and managers not at the conference? Communication applies to every manager, Anderson said. But he was the only operating manager present. And only one company sent operating supervisors. The remaining conference participants were public relations personnel, generally with nonmining backgrounds. And the program dealt mostly with public relations issues. Role of Communication in the Minerals Industry. It is well known that the minerals industry faces economic, political, and social problems. Economic shifts and foreign competition have created an international minerals industry and an international marketplace. This, in turn, calls for worldwide communication. Other factors effecting communication are: • Governmental protectionism as well as regulatory reforms call for increased interaction with governing officials. • Changing social values have created environmental issues and anti-industry attitudes. This intensifies the need for improved public relations. • Traditional work values are shifting towards self-actualization and humanistic movements. The work force is better educated and more informed. Employees demand more satisfaction, equality, and job autonomy. • The mining industry's task of managing its human resources is complicated by layoffs, job uncertainties, and bleak outlooks concerning employee morale and motivation. Technology and Information for a New Era As noted, this is a new communications era, one propelled by technology and information. Technology has led to reduced demand for raw materials by developing substitutes. Copper demand, for example, will never fully recover. Copper cables are replaced by fiberoptics; copper transmission lines, with aluminum. Technology has shifted the US from traditional to high tech and service industries. The speed, frequency, and scope of information transmission have greatly increased. But the most significant characteristic of this information is not the pace of advancing technology. It is the dramatic increase in the importance and frequency of our personal transactions. Knowledge has replaced raw materials and capital as the strategic resource. Information has replaced energy as the transforming resource. And the game against nature has become an interpersonal game (D. Bell, Post-industrial society, Physics Today, '76). In Megatrends, John Naisbitt says that information will soon double every 20 months. So, professionals will become "information workers." And communication will be the life channel of the information age. Thomas Wolfe said you can't go home again. Hanna Anderson said we are, indeed, facing a new day. It will never again be "business as usual." We must move into the information age with the rest of society. We cannot trust that the world will continue to rely on our products. Nor can we place the responsibility and control for problems and solutions outside the minerals industry. Improved communication is not a panacea. But, Anderson said, it is critical to the minerals industry. What is Communication? The word communication is overused. It is applied to every aspect of our lives. Satirist Tom Lehrer got sick of hearing about the need to communicate. He said, "It seems to me that if someone is having all that trouble communicating, the very least he can do is shut up!" Obviously, we cannot follow that advice (though we might wish that some others would do so). Communication is always going on. It is inevitable. Yet we have many misconceptions about com-

Jan 1, 1985

By Howard L. Hartman

Pardon my audacity, but I feel that this is the solution, not just a solution. Further, I will be so bold as to maintain that this is the last-ditch, eleventh-hour chance for the mineral industry to solve its critical technical manpower shortage. I am not being facetious. I am convinced that there is only one solution--just as there is but one real cause of the problem. My conclusion 'is reinforced by countless talks of endless hours with people both in and out of the industry, with employers and employees, and with educators and students. While I claim no originality for the idea and have no pride of authorship, I am concerned that the industry hear and heed in time. It is quite unlikely that the mineral industry and the mineral engineering profession will willingly subscribe to my thesis or gladly buy my proposal. I am convinced, however, that it is the only course of action open to us, and the only course of action which will succeed.

Jan 1, 1967

By M. Cambridge

The extractive industries are currently, and will continue to be, major contributors to the world economy, particularly in the developing world where economic growth is dependent upon a sound supply of primary materials. However, tailings dam and other mine failures have been very much a feature of recent anti-mining publicity, particularly in Europe, and thus instrumental in inhibiting new mine developments. Although, superficially, the record of dangerous incidents might support the anti-mining position, closer inspection suggests otherwise. This paper reviews the failures which have occurred over the last 50 years and demonstrates that, though poor practice is an ongoing problem for the industry, the record is one of improvement in both design and practice. Examples are provided of significant events which have led to dramatic advances in design and operation. The paper assesses the improvements made in technology and practice, and concludes that historic events must continue to form the underlying basis for design and operation of future mining projects.

Jan 1, 2005

By J. Dorsey

In 1910, Colonel Boyce Thompson, who owned Inspiration (now Cyprus Miami) and various other mining interests, formed the Magma Copper Company and leased the Silver Queen claims around Superior, Arizona. At the same time, he purchased other claims around the Silver Queen claims from what was then called the Magma Mine. The mine continued to operate until 1982 when Newmont Mining Company, who owned Magma Copper Company, shut down the operations due to high costs and low copper prices. When Magma was spun off by Newmont as an independent company in 1987, new studies of Superior were started. It was clear from these studies that the mine had been shutdown and over 1400 employees laid off for two basic reasons: first, as a resu1t of a mine plan that was technically flawed and second, be-cause of very high production costs mainly due to the low productivity from a very high cost work force. During 1989 a plan was formulated to re-open Superior with the determination to over-come the problems that resulted in closure. A new mine plan was developed and a management style developed that promotes team work and high productivity.

Jan 1, 1992

By S. Ash

Murray mine was one of the first Mechanized cut and fill underground gold operations in Northern Nevada. At the end of 2002 mine production began to decline and Murray entered a phase of remnant mining and began preparations to close down. The remaining mining took place along the ore waste boundary, in previously condemned areas, and in highly challenging ground conditions. To remain economically viable new techniques were implemented in operations, geology, engineering, and rock mechanics. These improvements pushed the edge of known and accepted mining practices and have allowed Murray to remain in operation today. History The Murray mine is located on the Jerritt Canyon property, which is located 45 miles north of Elko, NV in the Independence mountain range. Mining operations started at Jerritt Canyon in 1980 out of several open pits. In 1993 underground mining began in conjunction with a decline of surface mining operations. The transition from surface mining to underground mining moved the property into a new era. At the time there were limited examples of successful underground operations in the area from which to draw experience. Several mining methods were attempted with varying degrees of success and underhand cut and fill proved to be the most effective method. To date Murray has mined 1.2 million ounces at an average grade of .335 OPT utilizing this mining method.

Jan 1, 2006

By Viktor Tokle, C. W. Dawson

The Devico directional core drilling system and its capabilities are described, with reference to other directional drilling technologies and the advantages and disadvantages of these systems. The advantages and disadvantages of a number of borehole navigation systems are also presented. A discussion of the applications of the technology follows, illustrated by case histories. Finally, the environmental impacts and benefits of the technology, in comparison to more conventional systems, are presented.

Jan 1, 1999

By T. Yegulalp, K. S. Lackner

Zero emission coal plants capture their own CO2 emissions. Since they have no smoke stack, they emit no pollutants to the air. Zero emission plants circulate a gas stream, to which fresh fuel is added and from which spent fuel and impurities are removed as solids or liquids. Coal is gasified via hydrogenation, steam reforming or CO2 gasification (Boudouard reaction). The gas is oxidized in a fuel cell and the resultant water and CO2 are partially removed before returning the remaining gas to the gasifier. The high conversion efficiency of zero emission power plants, which exceeds 70% even in realistic designs, stems from combining fuel cells with careful heat management. The paper generalizes the concepts and outlines the thermodynamic basis of zero emission power plants.

Jan 1, 2004

By Scott W. Beckman, Leslie C. Thompson, Joseph A. Kizis

Heap leaching of ore with cyanide is a common and economical means of extracting precious metals (gold and silver) from mined ore. The use of cyanide, and the heap leach process, can seriously impact the environment. In the worst case, catastrophic failure of containment structures can release toxic levels of cyanide into receiving bodies of water, resulting in toxicity to ecological communities and contamination of public water supplies. Furthermore, cyanide degradation products such as nitrates can also impact local streams, lakes, and aquifers. Even if cyanide can be removed, the crushed residual ore may generate acid solutions that can release toxic heavy metals into the environment. Pintail Systems, Inc. (Pintail) of Aurora, CO, in conjunction with technology partners Science Applications International Corporation (SAIC) and Fairmile Gold Corporation (Fairmile), have developed a microbially-based precious metal lixiviant that can be used as an alternative to cyanide. The microbial process, called BioLix, is Pintail's second-generation biotechnology product for the recovery of precious metals from ore. The BioLix process is based on the enzymatic induction of organic lixiviant compounds using proprietary inducing agents and microorganisms. The process operates at near neutral pH and ambient temperatures using non-pathogenic microorganisms and food-grade chemicals. Precious metal extraction is also enhanced through the employment of microorganisms that facilitate mineral-solution reactions such as surfactant generation (improved wettability), and oxidation of gangue minerals that expose mineral surfaces to leaching. In order to demonstrate the effectiveness of the BioLix process, results from laboratory bench-scale experiments and a column study are presented. In addition, new applications for this enabling technology are discussed and include re-leaching of spent ore heaps, in situ leaching, and cyanide replacement for heap leaching.

Jan 1, 2000

By V. R. Bovino

You have afforded me the challenge of saying something profound in 20 minutes that will stay with you for 20 years. My hope is that from this presentation you will extract ideas that will move you? out of your offices, into the mine to seize upon the concepts that we will discuss. Your challenge is to transform those concepts into action and give life to the ideas discussed here. The notion of achieving limitless productivity produces peak levels of enthusiasm in today's mining leaders. Highly-productive mines do not happen by chance --they are created by progressive leaders. The quest for productivity improvement, exclusively through capital investment and technological advances, is an incomplete process. Improvement, through capital and technology, is often not achieved because we fail to energize the true potential and commitment in our employees.

Jan 1, 1991

By M. D. Lackey

The "Art" of Big Hole Drilling has been in a continual state of evolution at the Nevada Test Site since the start of underground testing in 1961. Emplacement holes for nuclear devices are still being drilled by the rotary drilling process, but almost all the hardware and systems have undergone many changes during the intervening years. The current design of bits, cutters, and other big hole drilling hardware results from contributions of manufacturers and Test Site personnel. The dual string, air lift, reverse circulation system was developed at the Test Site. Necessity was really the Mother of this invention, but this circulation system is worthy of consideration under almost any condition. Drill rigs for Big Hole drilling are usually adaptations of large Oil Well drill rigs with minor modifications required to handle the big bits and drilling assemblies. Steel remains the favorite shaft lining material, but a lot of thought is being given to concrete linings, especially precast concrete.

Jan 1, 1983

By Donald J. Donahue

Ladies and Gentlemen: As we begin these three crowded days of technical and economic discussion of problems faced by mining and metallurgical engineers, it seems appropriate at this Keynote Session to consider the future of this industry from which we derive our livelihood, It is also appropriate at this international meeting to view our industry on a world-wide basis. First, let us assess the world's future needs for minerals - the needs which it is our industry's task to meet. Next, let us look at what supplies of minerals may be available to meet those needs. I will speak of this first in terms of the physical availabilities of minerals. Finally, we can consider some of the social or institutional factors which will condition the world's mining industry as it goes about its task of discovering, developing, producing, and delivering the minerals needed to meet the world's demands. Let me give you a foretaste of my conclusions. First, future world demands upon our industry will be enormous, eclipsing anything that we have known up to this point. Second, there is strong evidence that our earth's crust contains a sufficient physical quantity and variety of minerals to meet forthcoming needs for as long a period ahead as one can envisage.

Jan 1, 1974

By D. S. Brown

Few issues pose quite as profound consequences to the quality of life and the creation and distribution of wealth as how we protect the natural environment. No longer a peripheral but a global concern, the environment, once almost nobody's business, has now become everybody's business. It is also the single biggest issue facing mining and mineral activities. This heightened ecological awareness and sensitivity have spawned a new commitment to restore, protect, and preserve nature. But that very commitment poses difficult socio-economic trade-offs, such as: What and how many resources can be given up to prevent and reduce pollution? What are the opportunity costs associated with meeting higher environmental standards? What problems are more important or pressing than others and should be given priority? Choices have to be made that may entail unintended consequences for other societal goals.

Jan 1, 1994

By Sam Ash

The Murray Mine was one of the first mechanized cut-and-fill underground gold operations in northern Nevada. At the end of 2002, mine production began to decline. So the mine entered a phase of remnant mining and began preparations to close down. The remaining mining took place along the ore waste boundary in previously condemned areas and in challenging ground conditions. To remain economically viable, new techniques were implemented in operations, geology, engineering and rock mechanics. These improvements pushed the edge of known and accepted mining practices and have allowed the Murray Mine to remain in operation.

Jan 1, 2006