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By Wayne F. Crockett, Martin H. Col

Gold, as a precious metal, has been sought for several thousand years. During this time economics have generally determined whether or not a deposit is minable. Today, few would spend $500.00 or $1,000.00 to produce one ounce of gold, yet most gold deposits currently being mined would have such costs if they were mined using the methods of the 18th century. Innovation has been the key to success in the world of mining. We are constantly having to look for new ways to mine deposits of lower grade, at greater depths, or with higher stripping ratios. The mining of placer gold deposits has always been subject to the volatile swings of the world price and the constant rise in production costs. The rise in costs is compounded by the drop in overall ore grades. Occasionally, a major technological innovation will dramatically reduce the costs of placer mining to allow previously marginal or unminable deposits to be mined at a profit. The continuous bucketline dredge was the last such major innovation in the gold placer mining. The continuous bucketline dredge has allowed large volumes of placer deposits to be picked up and processed on a continuous basis. Unfortunately, as the overall grade of the deposit declines, it becomes impossible to process enough ore to pay for the operating costs. There are many gold deposits around the world waiting for the next technological innovation that will allow them to be mined. One such deposit has been the Grey River deposit near Greymouth in New Zealand. The deposit contains gold reserves of 8992 kg, yet the deposit has been sitting idle for many years because the average value

Jan 1, 1988

By Christian Jeger

After recalling the principles underlying fire-damp flow in coal and the essential part played by permeability (Darcy's law) in the intensity of flow, a few theoretical and experimental results showing the possible causes and range of variation of coal seam permeability are presented. The study of firedamp flow into gate roads and of residual gas concentrations in coals as a function of the gate road distance, shows that, in French mines, coal seams in a virgin zone have a very low permeability, but they become permeable when destressed by mine workings, in particular overlying workings. This is the case not only in the fractured zone round a mine excavation in which the gas is released, but also beyond the limit of the zone degassed by the excavation. In the floor of flat seams, upward boreholes can be used for predegassing seams that have been relaxed but not degassed, as the result of an overlying coal face. In this respect we shall describe the predrainage experiment carried out in the Marienau district of the Lorraine coalfield. Predrainage can contribute considerably to the reduction of methane emission in the ventilation of newly opened longwall faces. But to be efficient and useful predrainage should meet certain conditions.

Jan 1, 1980

By John O. Marsden

Technology development has played a crucial role in the minerals industry throughout history. The development of new technology allows mankind to produce metals and minerals at progressively lower cost of production in real terms, and therefore at progressively lower prices, improving their availability, accessibility and utilization worldwide. However, the developers of such technology are not guaranteed to reap the benefits from this effort: There is an expectation that technology developers will gain an advantage over their competitors. Is this a short-term benefit that results from a temporary cost or efficiency improvement, or is it a sustainable longer term "edge" that prevails even after metal or mineral price has been eroded by the implementation of a major step change technology? This issue is examined by reference to several case study examples in the copper industry. BACKGROUND The development and adoption of new technology has played a crucial role in the commodity minerals industry throughout history. As new, cost-efficient technologies are commercialized, the cost of production decreases, and this enables lower grade ore to be processed profitably. This in turn increases the availability and supply of the metal or mineral of interest, and ultimately (in a free market environment where the supply- demand balance determines price) inevitably decreases the metal or mineral price. This leads to the question: Why should mining companies invest in (new) technology development if the result is a decrease in the product price? The answer is to achieve competitive advantage, where the application of new technology enables one or more

Jan 1, 2004

By R. C. Shodde, R. D. La Nauze

Major societal and industry changes over the last four decades have influenced the management of technology in the minerals industry. From the authors' experiences in both private and public sector R&D, the paper analyzes the range of strategic and structural changes and provides examples of some key technology delivery responses. For those charged with managing technology, the two key challenges facing them over the next decade are (I) moving technology development from a cost focus to a value focus (that is, from "how much long-term research can we afford?" to "identifying and capturing the value created from R&D”) and (2) the recruitment and retention of key talent. THE NEED TO ADAPT "Change is slow and gradual. It requires hard work, a bit of luck, a fair amount of self- sacrifice, and a lot of patience (Greene 1998)." Since the 1960s the world has changed and the minerals industry has had to adapt to the changing circumstances. In the '60s, minerals were there to be discovered and fortunes to be made; in Australia, the World War I1 embargo on exporting iron ore was lifted and the Western Australian iron-ore boom commenced, to be followed by the exploitation of the Darling Range bauxites; copper, lead, zinc and nickel were discovered and mines developed. The Australian dollar was worth US$1.11 whereas today it is around US$0.65. The oil crisis of 1976 sharpened focus on the sensitivity of the minerals industry on energy costs. By the late 1970s The Club of Rome was predicting the imminent demise of certain key metals-a prediction that has not been fulfilled-though the signs of the shift

Jan 1, 2004

By Van E. Housman, Stephan Hoffman

Introduction Based upon the 1980 Bevill Amendment to the Resource Conservation and Recovery Act (RCRA), a 1986 Regulatory Determination decision, and subsequent rulemakings, the Environmental Protection Agency (EPA) exempted all extraction and beneficiation wastes and twenty mineral processing wastes from regulation under RCRA Subtitle C (hazardous waste) regulations. These twenty mineral processing waste streams were studied in a 1990 Mineral Processing Report to Congress. For purposes of regulatory classification, EPA made special distinctions between extraction/beneficiation and mineral processing. Wastes determined by EPA to be from the extraction/beneficiation of ores and minerals retain the exemption, while wastes found to be mineral processing, except for the “special" twenty mineral processing wastes, fall within RCRA Subtitle C jurisdiction. For those wastes that are subject to RCRA Subtitle C, § 3004(m) of RCRA requires EPA to set levels or methods of treatment, of any, which would substantially diminish the toxicity of the waste or substantially reduce the likelihood of migration of hazardous constituents from the waste so that short- term and long-term threats to human health and the environment are minimized. These treatment standards are developed by EPA under the Land Disposal Restrictions (LDR) program. Under § 3004(g) (4) of RCRA, EPA is required to promulgate treatment standards for any waste that is newly identified or listed as hazardous. As part of the settlement agreement in Environmental Defense Fund (EDF) v. Reilly and Chemical Waste Management, Inc. v. EPA (1992), EPA has agreed to propose a rule by June 30, 1995 and promulgate a final rule by June 30, 1996. This rule is commonly referred to as the "Phase IV" LDR rule and will address newly identified mineral processing wastes. Other wastes that will be addressed in this rule include newly listed dyes and pigments and wood preserving wastes. Therefore, in the Phase IV rule EPA will develop treatment standards for all mineral processing wastes that have lost their Bevill exclusion. EPA is currently collecting information on the waste characterization, treatment alternatives, and disposal capacity data currently available on these wastes. EPA is also soliciting data and information on opportunities for

Jan 1, 1995

Africa is rich in natural resources, much of which remain untapped. Despite that, international mining companies have largely stayed away from the continent due to political instability in many countries, lack of infrastructure and the inability to gain control of mineral deposits. Today, optimism is growing concerning African mining. Many of its nations are moving toward privatization of their mining industries. They see it as a way to improve the lives of their populations and become politically stronger. Ministers from 22 African nations were Denver, CO in June for the World Bank's Multilateral Investment Guarantee Agency's Fourth Annual African Mining Investment Symposium. The three-day symposium drew more than 400 mining executives and government representatives. Foreign mining investment in Africa is on the increase. In 1996, international mining companies spent about $418 million on exploration. That is more than double the $190 million spent in 1994. Mining executives say the mining climate in Africa is improving because countries are privatizing the industry and rewriting mining laws that encourage natural resource development. They estimate that private mining firms now control about 80% of mining today. Mine development will help lift the living standards for Africans, the ministers said. The average income for ordinary Africans is about $500 a year. If this new mining boom continues, citizens of nearly all African nations will reap the benefits of better infrastructure and government services, as well as more higher paying jobs, the ministers said. They also issued a word of caution to mining companies attempting to join in the African boom. Concerns are being raised about the treatment of villagers and the environment. In the past, foreign companies would "behave about like colonial masters," said Gerald Ssendaula, natural resource minister for Uganda. Africa is in a different position now, he said. "Now we are solving our own problems." Mining companies must respect local communities or risk creating unrest that will threaten fragile new governments, said Akolang Tombale, chief geologist for Botswana. On the other hand, he said villagers must accept that mining development will benefit them. "They feel these are their natural resources. There must be a mutual interaction between the companies and the people."

Jan 1, 1997

By J. den Drijver, M. Opahle, R. Inderst

Safety reasons render necessary the advanced calculation of the amount of methane degassing from a longwall in the scope of the ventilation planning of mines. Today empirical methods, which are based on observations of operational procedures, are used for the calculation of the amount of methane. Despite of constant improvement those calculations are not always sufficient. In particular calculations which are based on operational facts but not proved by experience are not reliable. Most of all these calculation procedures lack physical-analytical descriptions of the procedure itself, presenting only the effects on important parameters such as the distance between seams in the roof or floor or gas pressure. Tschersich [Tschersich 961 developed an analytical model for an advanced calculation by analysing the degassing of seams in the roof and floor and the physical parameters of gasflow. This model might correct the lacks of existing procedures and improve the precision and reliability of additional calculations. The model simulates the emission record in seams of the roof and the floor. It takes into account not only a multitude of parameters such as the distance to adjacent seams and gas pressure but also the depth of seams, gas content, rank of carbonification, rock temperature, face advance rate, initial and succeeding mining and the face length. In order to comprehend and to verify those correlations we extended the model of Tschersich and programmed this enlarged model using the computer language C++. Aim of this research is to guarantee a much higher accuracy in calculating methane emission caused by mining. The improved planning is expected to result in more safety and better prevention of high methane con- tent in ventilation as well as in a better use of the capacity of the mining equipment. The application [Drijver, lnderst 961 of the ex- tended model will also be very useful in the course of research projects as it allows computer simulation, i.e. in-situ research can be extensively limited or even replaced.

Jan 1, 1997

By J. F. Archibald

It is often alleged by mine ventilation engineers that no reliable method exists to forecast the levels of radiation to be encountered in future uranium mines. It results that the design of uranium mine ventilation systems is based on factors other than radiological hazards, such as radon and radon daughter concentrations, for which permissible limits are set. Ventilation has been used to date as the main control mechanism for radon and radon daughters. Although it has become increasingly difficult to provide enough ventilating air to reduce the radon gas and its daughter products to safe levels in some mining arrangements, it is not the object of this paper to discuss alternatives to ventilation. This paper will describe a methodology followed by the authors over the years to estimate the levels of radiation to be encountered in underground and open pit uranium mines. Ventilating air is used to maintain working level concentrations within safe limits. The sources of radon and radon daughters and the quantities of each which will be produced, will be of great value in planning and designing a ventilation system to control them. This information can afterwards be integrated into the overall mine design. The methodology to be outlined can also be used to estimate, given a mine design format, the radiation levels to be encountered. If levels are not acceptable, modifications in the mine design can be made at an early stage. The emphasis is placed on an integrated effort where the ventilation engineers and the mine design engineers work in close collaboration from the very start of the mining project. Estimation of radon and radon daughter levels can be initiated as soon as core samples are obtained from the exploration programmes.

Jan 1, 1980

By E. S. Smith, Sunirmal Banerjee

INTRODUCTION Social awareness of the detrimental impact of man-made wastes on our environment has grown considerably during the last two decades. Increased public and institutional concerns have resulted in the implementation of a wide variety of regulatory controls of disposal of wastes. These regulations have often reflected significant conservatism in expecting guaranteed elimination of pollution risks. This sort of expectation assumed a state of knowledge which was not readily available to the major producers of wastes. The mining industry, in particular, has been affected by such regulations in terms of excessive costs and loss of benefit. As a result, investigations are in progress (1) to generate newer methods for satisfactory stabilization of mine and mill wastes and (2) to apply the available technology to achieve the standards set by the regulatory agencies at reasonable costs. This paper presents a conceptual scheme for stabilization of mill wastes by suitable management of operations and accelerated consolidation of tailings slurries. The main discussion in this paper is aimed at the ability of the proposed scheme to address the major considerations in effective disposal. Comparison in both cost and effectiveness are also made between the proposed scheme and various other currently used disposal concepts. MAJOR CONSIDERATIONS IN EFFECTIVE DISPOSAL The primary objective of an effective tailings disposal scheme is to provide containment of the contaminants in such a manner that the undesirable impact of the wastes on the three basic elements of our environment--land, air, and water-would be minimal. Bearing the above objective in mind, one may justifiably list the major considerations in the choice of the disposal scheme in terms of its effects on land, air, and water (Bromwell, 1976) as follows: Effects on Land (1) whether the scheme makes optimal use of land.

Jan 1, 1980

By L. J. O’Connor

Mining activities in the small historic mining camp of La Colorada in the state of Sonora, Mexico can be traced back to the mid eighteenth century when gold was discovered and exploited by Jesuit missionaries. Following one hundred and twenty six years of activity, the mines were shut down due to the Mexican revolution. Very little activity took place until 1989 when a company, Minera Las Cuevas, spent US $350,000.00 in mapping and sampling and diamond and reverse circulation drilling over a period of three years. During 1991 HRC Development Corporation entered into a joint venture agreement with Minerales de Sotula, S.A. de C.V. that allowed an earn in of 70% interest. Exploraciones Eldorado, S.A. de C.V. and it's parent company, Eldorado Corporation Ltd. were subsequently incorporated by HRC to hold the La Colorada project. Property evaluation ensued and a thirty thousand tonne Run of Mine test heap was leached from August of 1992 until May of 1993. Full scale commercial production commenced in late November, 1993 and the first gold/silver doré bar was poured early in January of 1994. Pre-production costs were a total of approximately four million dollars U.S. During the fall of 1994 a buyout of the venture partners' interest gave Eldorado one hundred percent ownership of the property. The first two years of mining have utilized a local contract mining fleet and have placed nearly two million tonnes of ore on a run of mine heap. Low cost ripping and dozing mining methods have been employed in conjunction with drip irrigation leaching. An initial pilot plant carbon adsorption circuit was supplemented with a Merrill Crowe recovery circuit in June of 1994 and was completely replaced with the construction of a second Merrill Crowe circuit in July of 1995. Approximately fifty thousand troy ounces of gold and over one hundred thirty thousand ounces of silver will have been poured by year end 1995. Ongoing, on site exploration continues to increase mineable reserves in the known deposits. A feasibility study is ongoing concurrent with the operations and will provide the basis for future elevated production levels. Exploraciones Eldorado continues to explore outward from the current operations and several anomalous outlying zones may play part to the long term economic growth of the company in Mexico.

Jan 1, 1996

By D. Wallace Fields

Increasing public pressure and demands from various tiers of government have generated a legislative maze of statutory and administrative requirements facing industries involved in mineral extraction and processing. Each tier, of government has asserted concurrent jurisdiction and threats of harsh measures if industry does not satisfy all requirements. In the field of water pollution control, federal requirements have increased, carrying with them increasing techniques of enforcement - ranging from injunctions through criminal penalties. Federal laws have required that states formulate water quality standards as an adjunct to federal regulation. Florida has reacted with the Water Pollution Control Act of 1967. This act incorporates state water quality standards and permit requirements for any installation constituting a potential source of pollution, and provides for civil sanctions as well as injunctive relief. The federal government has utilized an 1899 law to require a permit for discharges into navigable waterbodies - a term which has been judicially defined to include any watercourse capable, after reasonable improvement, for use in the transportation of waterborne traffic. Failure to secure these permits can result in the issuance of an injunction or civil or criminal penalties. The Corps of Engineers will not issue these permits without the approval of the discharge by state, local and other federal agencies. Air pollution similarly is regulated by a multi-tiered network of laws and administrative standards. Federal regulation has increased from early research support in the 1950's through the development of Air Quality Standards and their enforcement by large fines, injunctions, administrative conferences and public hearings. Florida regulation, under the Florida Air Pollution Control Act of 1967, parallels federal law but grants concurrent regulations, requirements and enforcement tools to local and state agencies. Although previous state regulation was minimal, consisting only of three acts passed in 189 1, 1899, and 1911, in the future the mining industry will have to contend with this increasing network of ecological requirements. It is recommended that the industry take the initiative by involving Florida in the Interstate Mining Compact, as well as seeking the passage of a state reclamation law funded by a severance tax.

Jan 1, 1972

By Z. Kowalski

In the defunct Gorka quarry, there are situated both a waste disposal site of an area of 6.7 ha and containing approximately 1 million ton of high aluminium wastes and a pond of an area of roughly 3 ha, up to 15 m deep, with about 400000 m3 of polluted water. The reservoir is fed with the filtrates arriving from the disposal site mentioned, at a rate ~130 m3/day. An alarming phenomenon is the subsidence of the pond bottom and the infiltration of solutions into the Triassic and Jurassic water resources, assessed at ~40 m3/ day. The basic problem related to the effluents in the Gorka pond is their high alkalinity (pH 12-13.4) and variable pollutants whose level increases appreciably with the pond?s depth. The solution offered provides pumping out and treatment of about 500000m3 of effluents retained in the Gorka reservoir in an about yearly time. Effluents would be treated in a reverse osmosis plant, according to a process so far verified on a quarter-commercial scale. The treatment process by-product would be discharged into the Ropa stream. The brine solution (containing about 25% NaCl), whose amount may reach up to100000m3, might be supplied to the Debiensko Mine which produces technological salt from salt-bearing mine waters. Similarly, there would be provided an intake of underflows of infiltrates (by means of deep wells, and possibly girdling ditches) arriving from the high aluminum site, and such effluents would be subject to ongoing dilution in water courses. It would be possible to test the system of underflows reaching the Gorka reservoir by means of geochemical identification, previously performed. The next stage following the pumping, would be the utilization of approx. 50 000m3 of bottom slurry. Highly alkaline slurries would be utilized in the production of self-solidifying mixtures. Slurries would be pumped out and temporarily dumped on drying beds, located nearby the Gorka reservoir, and later on used successively for making self-solidifying mixtures in a plant similar to a concrete making seat. Those mixtures would be applied for sealing the bottom of the Gorka reservoir and the necessary part of the edges of the defunct quarry. An alternative solution is the utilization of slurries in the facilities of the Trzebionka Mining Works and the application of self-solidifying mixtures, made in the Trzebionka Works, for sealing the reservoir bottom.

Jan 1, 2006

By M. H. Basiri

Crude oil, as a central commercial commodity, is tied to major economic activities in all nations. Also its price fluctuation plays a significant role in global political and economic situation, as a change in the price invariably affects the cost of other goods and services. Therefore reliable forecasts of the price of oil are interest for a wide range of applications. Several approaches have been proposed over the past few years. These may divide into three categories; artificial intelligent, statistical techniques and hybrid methods. The neuro-fuzzy is one of the sub divisions of hybrid method, containing neural network and fuzzy techniques. In this paper a novel forecasting model based on adaptive neuro-fuzzy inference (ANFIS) is proposed to predict monthly crude oil price. To be able to train and test the model, the statistical data from 1990 to 2010, was obtained from West Texas Intermediate oil prices. The results are compared with a multi criteria regression analysis, it is demonstrated that the neuro-fuzzy lead an accurate and more promising forecast.

Jan 1, 2012

By Alan G. Mayton, Jon C. Volkwein

The U.S. Department of the Interior, Bureau of Mines, in cooperation with an American firm, has been contributing toward the creation of a new highwall mining system for extracting coal in active, unreclaimed contour strip mines in the United States. The prototype system features the computer-based, remote control, video operation of a thin-seam continuous miner. Haulage is accomplished remotely also with a 76-m (250-ft) long multiple-unit continuous haulage (MUCH) conveyor system on rubber-tire vehicles. One aspect of this multi-faceted effort has been to design a ventilation system for removing dust generated at the face during the extraction process. The remote mining system eliminates the need for personnel in the mined workings. Ventilation is required to remove visible dust from the area inby two video cameras. These cameras are located approximately 6 m (20 ft) from the face, one on either side of a modified Jeffrey 102HP continuous miner. Removing the dust from this area provides the remote operator with constant visual monitoring of coal extraction at the face and thus, insures the effective operation of the mining system. A ventilation system was designed for use in a mine opening with a maximum cross-sectional area of roughly 4 sq m (44 sq ft) excluding the mining machinery. This paper describes the ventilation system and discusses how it was developed in view of the constraints imposed by the mining equipment, mining conditions, and the extraction process.

Jan 1, 1989

By Walter E. Jaworski, William R. Beloff, John Dunnicliff

As a step in the endeavor to reduce future tunneling costs in New York City, the Environmental Protection Administration, Dept. of Water Resources, instituted a program in 1972 to monitor the performance of the lining of one of its tunnels. A monitoring program was included as part of the contract specifications for the East Branch Interceptor Sewer tunnel for the Port Richmond Water Pollution Control Project in the hope that measured data would indicate possible future cost effective design or construction improvements. The monitoring program involved measuring ground deformations, circumferential liner stresses, longitudinal liner stresses, and jacking pressures. This paper presents some of the findings from these measurements, with emphasis on liner stresses. PROJECT DESCRIPTION The 3.05m (10 ft) diameter steel lined tunnel was constructed under two separate contracts. The easterly portion, Contract 3A, was approximately 3109m (10,200 ft) in length and constructed by Peter Kiewit Sons Co.1 The westerly portion, Contract 3B, was approximately 2160m (7100 ft) in length, and constructed by Richmond Constructors, a joint venture of Grow Tunneling Corp., MacLean Grove & Company, Inc., Grove, Shepherd. Wilson & Kruge, Inc., Morrison-Knudsen Company, Inc., and Andrew Catapano Co., Inc. Each contract included three test stations, hence a total of six along the tunnel route. Excavated material along the tunnel route consisted primarily of dense fine to coarse sand with varying percentages of gravel and silt with occasional boulders. Pockets of organic silt were encountered on Contract 3B and a large portion of Contract 3A ran through slightly weathered serpentine and schist. Overlying material and the groundwater level varied considerably along the route as did the height of overburden. Figures 1 and 2 show the generalized soil profiles for Contracts 3A (PK stations) and 3B (RC stations) respectively.

Jan 1, 1979

By Paul C. Miclea

Hanford Reservation, in the State of Washington, with its deep basalt formations, is one of the three sites recommended by the Department of Energy for detailed investigations in order to select the first nuclear waste repository in the United States. Information obtained from several deep bore-holes drilled at Hanford indicates that the underground facility can be developed in one of the major basalt flows belonging to the Grande Ronde Formation in the Columbia Plateau, at depths greater than 3200 ft. One of the main concerns in the underground repository design is the achievement of acceptable environmental conditions during the development and the operation of the repository. For this, ventilation and air-conditioning are of prime importance and should be fully addressed. Besides the factors that determine the airflow requirements to meet the personnel and equipment operation needs, there are two major concerns that impact on the ventilation system design: the temperature of the in situ virgin basalt rock and the influx of groundwater. These two factors are related by the fact that the groundwater has the same temperature as the rock itself and they both constitute main sources of heat underground. Current information indicates that the temperature of the virgin rock at a depth of around 990 m (3250 ft) is 52°C (12S°F). However, there are some indications that the rock temperature at the selected horizon might be higher. This paper addresses the impact of the virgin rock temperature on the ventilation system and air-cooling requirements. Graphs with heat loads and cooling required for different rock temperatures have been prepared for a given model and network, using computer techniques for simulating the climatic parameters.

Jan 1, 1987

By Nicholas T. Camicia

A career in the coal mining industry today offers students one of the most interesting and challenging opportunities available in the industrialized world. As reserves of other fossil fuels dwindle in face of the world's demand for energy, it has become apparent that coal, once the king of energy sources, must be relied upon again as the major fuel for powering industrial growth in developed and developing nations. Centuries of coal supplies lie beneath the earth's surface, assuring the world of a steady, plentiful supply of energy until science and technology can produce a way to harness and efficiently use renewable sources, such as solar. The need to increase our use of coal during the last two decades of the 20th century is reason enough to believe that the future growth of the coal industry is assured. A major impediment to that growth might be backward national public policies that could restrict the full utilization of our coal reserves. These policies could result from overregulation and a failure of the public to recognize that coal use, with proper techno- logical safeguards, is compatible with our society's environmental-quality objectives. Communication of this problem and its solution is a major undertaking of the coal industry in the 1980s. At the end of the 1970s, the American coal industry was producing approximately 635 Mt/a (700 million stpy) of coal. To meet the nation's projected energy needs by 1985, the annual tonnage must be doubled. A similar scenario is predicted for the rest of the world. Such growth in the modern international business world will require huge additional amounts of capital, equipment, and people who know how to wisely raise and apply the capital ; use the equipment productively; and deal with the many community, public, and governmental problems such expansion will create. Whether a student's interest is in actual mining operations, business administration, engineering, finance, law, industrial relations, marketing and sales, or public affairs, a career opportunity is available in the industry.

Jan 1, 1981

By Y. J. Wang

Optimal sizing of a ventilation shaft is a classical subject in mine ventilation economics.. The shaft size is optimized by minimizing the sum of shaft-construction and ventilation-power costs, or owning and operating costs. The length and air quantity of the shaft are held constant, and the location of the shaft, affecting its depth, and construction and ventilation power costs, is not considered (Hartman, 1961; Lambrechts, 1974; Wang et al., 1978). This paper proposes an approach by which the location and size for a new pair of shafts (intake and return shafts) are optimized for a coal-mine ventilation network. Specifically, the problem is to determine the location and size for a new pair of shafts, and the distribution of air between the new and old shafts so that the combined cost of shaft construction and ventilation power is minimized. The shaft length or depth corresponds to the height of overburden at any shaft location. To simplify the problem, the shaft locations will be limited to the line along the main or submain entries, and the connection entries at the shaft bottom neglected. In order to calculate the ventilation-power cost, the air power of the system should be determined. This in turn requires the calculations of the air quantity and pressure of each fan in the network, satisfying Kirchhoff's laws and Atkinson equation. After obtaining the air power, the cost calculation is straightforward. In the following, we shall assume that the resistances of all airways, and the quantity for each mining section, which is controlled by adjusting the air regulator, are all known. The resistances for the shafts are determined from the estimated friction factors, and shaft dimensions and lengths. Furthermore, it will be assumed that the fans can be selected to meet the duties called for by any network solutions.

Jan 1, 1982

By Ronny J. Sadri

Under contract to the Department of Energy, Fluor Mining & Metals, Inc. and Bonner & Moore Associates developed a group of computer models that can be used to simulate single seam dragline operations. These models have been subsequently modified by Fluor for use in multi-seam dragline mining situations. The single seam model analyzes the digging, spoiling, and walking patterns of draglines to identify possible parameter changes to increase productivity. Parameters such as key-cutting, panel width, digout length, and bench height, etc., are analyzed in this process. The models were tested using data from four operating mines. Field demonstrations were performed to correlate computer optimization results with field data. Productivity was greatly enhanced at one mine site by a change in some of the operating parameters. The multi-seam study has as its objective the development of a broad- based mine planning tool which would be used to identify and quantify the different procedures employed in multi-seam dragline mines to increase their productivity. The major problem identified in multi-seam mining is the sequencing of the different stripping and mining operations. The multi-seam model has the same capabilities as the single seam model. In addition, it models up to four seams with three partings per seam. It allows the operation of several draglines at different levels, and analyzes the effect of ramps, rehandling, and ancillary mining equipment.

Jan 1, 1982

By Lynn B. Hales, Randy A. Ynchausti

Introduction There continues to be a large economic opportunity associated with improving process performance through advanced process control systems within the minerals industry. The basis for this opportunity lies in the inherently low efficiencies of many of the unit operations found in mineral processing plants as well as the continual variation that is present in the ores being processed. The ageless target of such control systems is improved recoveries and concentrate grades, higher processing rates and lower unit costs. Many plants are enjoying the benefits of modem, well functioning process control systems but few if any have achieved plant-wide optimization in an economical sense. As new process modeling and control technologies, such as neural networks, continue to evolve and develop, the potential for plant- wide optimization is becoming a closer reality. Neural network technology appears to have a significant potential in the general field of process control and control of mineral processing operations. Neural networks are an emerging technology that have been evolving out of the study of biological systems since the early 1940's. The first software simulation of neural computing networks was reported in 1956 by Nathanial Rochester of IBM Research during the first conference on artificial intelligence which was sponsored by the Rockefeller Foundation. Neural Networks Neural networks can be considered to be a class of computer program that perform their problem solving functions based on a rudimentary model of the human brain and how it solves problems. Traditional computer programs and even computers themselves solve problems or process data sequentially and in a deterministic manner. The human brain, on the other hand, processes data and solves problems in a massively parallel fashion. We think of computers normally in terms of having a single processing unit, sometimes a co-processor to assist in certain activities such as mathematical functions or communications, bytes of memory, processing speed and program/data storage size.

Jan 1, 1992