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By Gary W. LaChapelle

Cyprus Miami Mining Corp. has a history of overcoming adversity through innovation and adaptation to changing conditions. Requirements to remain profitable in the 1990s include a combination of advanced technology, employee involvement and training, attention to customer satisfaction, environmental awareness and quality management. The Miami property is located in the Globe-Miami area of Arizona, 130 km (80 miles) east of Phoenix and 160 km (100 miles) north of Tucson. The complex is located in a high desert environ¬ment at an elevation of 1065 m (3500 ft). The region receives about 480 mm (19 in.) of precipitation annually. History Mineralization at the Miami property was first discovered in the 1880s, which led to underground mining of copper by the 1890s. In 1911, the Inspiration Consolidated Copper Co. was formed by combining the Inspiration and Live Oak Mines. Full-scale production began in 1915. Block caving methods were used at both mines. Open-pit mining commenced in 1948. Underground mining had ceased by 1954, and all production was obtained from surface operations. Innovation has been the key to Miami's success. Development of sulfide flotation and the ferric cure process for vat leaching were advanced at Miami. In situ leaching of oxide material, remaining after block caving had removed the sulfide ore, was also used.

Jan 1, 1993

By L. S. Gourevitch, E. B. Kremer, A. Y. Fidlin, Y. M. Katsman, I. I. Blekhman

A new kinetic approach to simulation of fracture is given. The main object of the simulation is forecasting transformation of ore lumps size distribution in squeezing of ore layer between two planes. The approach rests on fundamental principles of energy and mass conservation and on new ideas about fracture physics connected with fractal geometry. On this base an integro-differen tial equation of layer crushing kinetics is formulated. This equation is similar to well-known kinetic equation of grinding, but here we use elastic energy density in place of time as an independent variable while selection function is considered by us to be dependent on this variable. Properties of the equation have been investigated by us and its analytical solution has been found. It allows to compute simultaneously both the evolution of the size distribution process of squeezing and force-displacement diagram. Results of theoretical calculations provide a good fit with experimental data.

Jan 1, 1995

By A. John R. Hart

INTRODUCTION The use of precast concrete tunnel liners as the initial and final tunnel lining for transit systems has been a major consideration of designers for over three decades. The obvious benefit of building a tunnel that requires only a single pass in constructing the structural lining can provide the opportunity of saving both time and cost. This technique has had worldwide application in transit systems in London, Munich, Hong Kong, Toronto to name a few. In the United States precast liners were evaluated for use on the BART System in San Francisco in the early 1960's but did not provide sufficient confidence in the sealing capabilities available at that time. In 1976 it was decided to call for bids on the Lexington Market Tunnels in Baltimore with a precast concrete liner alternative for one of the tunnel drives. This option was selected by the owner and UMTA to provide a study evaluation for the benefit of the industry. HISTORY In 1983 Washington Metropolitan Area Transit Authority began calling for a series of bids on soft ground tunnels on the Green Line, which included the option of using precast concrete tunnel liners first as an alternative to fabricated steel tunnel liners. Over the years following, the precast concrete tunnel liners have become known as the conventional tunnelling system and, in the last year,

Jan 1, 1989

By Robert G. Moorhead

Fine-coal screening can be one of the most critical operations in a modern coal-cleaning plant. The yield and quality of clean coal produced in fine-coal circuits is controlled as much by how efficiently 0.15 mm (100 mesh) particles are sized as on the performance traits of the fine-coal cleaning device itself. In addition, the increased interest in effective fine-coal sizing operations indicates that many operators have also discovered its importance in affecting the quality and yield of clean coal produced in fine-coal circuits. This paper describes the three most prevalently used fine-coal screening technologies and discusses their sizing mechanism, performance, and application.

Jan 1, 1988

By R. Houot, C. Leschevin, G. Gillet

In mineral processing, conventional magnetic separators are equipped with traditional magnetic circuits (magnetic iron yoke with copper coils or iron-clad solenoid) that develop magnetic fields of less than 2 T'. For minerals of low magnetic susceptibility, use of these circuits has many disadvantages. Only a separator with a superconducting magnet can contribute to solving the problems and produce a high magnetic field. This paper presents and describes a magnetic separator having a superconducting magnet with integrated closed circuit for helium liquefaction. The system generator and maintenance are simplified by extensive automation realized by a versatile program- mable autocontrol unit. A comparative study if the results on concentration and purification of different raw materials with the new and with conventional separators is described.

Jan 1, 1987

By Steve Karl, Rock Jenkins

Continuing its objective of sharing new ideas, methods, theory, and engineering developments, more than 550 members of the underground fraternity gathered in New York City for the 1985 Rapid Excavation and Tunneling Conference (RETC). Since the first meeting in 1972, RETC’S aim has been to lay a foundation of tunneling experience on which the industry could expand and develop over the years. The RETC is jointly sponsored by the American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME), the American Society of Civil Engineers, in cooperation with the Canadian Institute of Mining and Metallurgy, and the Engineering Institute of Canada. The 17 sessions included 72 papers that explored up-to-date practices in the mining and civil engineering fields. Session topics ranged from geotechnical and seismic design, through design, construction, and support of underground openings, to ground water control in shafts and mine openings. Case histories of tunnel boring machines and large diameter tunnel and underground openings were also reviewed. All the papers presented at the three-day conference are valuable additions to improving the state of rapid excavation. A few sessions, however, are particularly noteworthy as they are geared to the mining industry. The two volume proceedings of the entire conference are available from SME. (See ad on page 1003).

Jan 7, 1985

By Irwin R. Higgins, Richard S. Dennis

Acid recovery employs ion exchange resin as an adsorption media for the separation of inorganic acids from mixtures of acids and their metallic salts. This technology has been used to treat spent pickling and plating liquors to recover acid for reuse in the bath and to reduce waste acid neutralization costs. Acid recovery can also be used for electrolyte treatment to facilitate valuable metal recovery and to improve product quality. Conventional fixed bed ion exchange (I-X) systems are impractical for acid recovery because of complex control design and large resin inventories needed to process strong acid concentrations. TETRA'S CCIX™ continuous I-X contactor has been used successfully in a simple, continuous operating mode to separate acid from its salt. Efficient separation is enhanced by refluxing which allows acid to be produced as a salt-free product at nearly its original strength. Continuous treatment also recovers heat to the bath and improves metal quality due to consistent acid quality.

Jan 1, 1995

By Wilhelm J. Kogelmann

The quest for U.S. energy independence will result in a major increase in underground mining operations. It will necessitate the rapid excavation of development drifts, entries and slopes to exploit underground deposits of energy resources such as coal, uranium and oil shale. Most of this development work will be done in soft and medium hard rock up to an unconfined compressive strength of approximately 20, 000 psi. OBSTACLES TO RAPID TUNNEL EXCAVATION Labor In the U. S. coal mining industry, the underground productivity in tons per man-day declined from 15. 61 in 1969 to 11. 00 in 1973 which is a startling 30% decline. While productivity declines, the cost of labor and supplies continues to rise. Ralph E. Bailey of Consolidation Coal Company recently stated four reasons for the decline of productivity: A shortage of experienced miners, enactment of the Federal Coal Mine Health and Safety Act effective April 1970, major changes in union work rules in 1968, and a deterioration in the attitude of the work force (1). Because there is already a great shortage of skilled miners, the situation will get worse when large new mines for oil shale, coal and uranium open in sparsely populated areas in the Western United States. Only the large scale use of easy to operate tunneling machines can increase productivity and lower the cost of excavation.

Jan 1, 1974

By Pierre M. Matheron

TRANSMANCHE-LINK is responsible for designing, developing and implementing the project for a fixed link under the English Channel, comprising two running tunnels of diameter 7.6 metres and a service tunnel of diameter 4.8 metres. The three tunnels will all be 50 km long, with 37 km bored through chalk marl at a depth of 40 metres under the sea bed. The tunnels will be driven from both sides of the channel from intermediate addits above the coastline on either side with a 55 m access shaft at Sangatte in France and two "descenderies" or inclined tunnels addits and a shaft at Shakespeare Cliff on the English side. A total of eleven tunnel boring machines will drive the 150 km of tunnels. The major part of the tunnel linings will be built of precast reinforced concrete segments, and two plants have been specially built to produce the necessary 725,000 segments. Seven million cubic metres will be evacuated on wagons along the tunnels and then lifted by belt conveyor on the English side, and by hydraulic mucking from the bottom on the French side. Preliminary work started early in 1987 with manufacture of the first boring machines, construction of five precasting plants, boring of the Sangatte shaft in preparation of the Shakespeare Cliff entrances. The principal project dates are :

Jan 1, 1987

By Siegmund Babendererde

Introduction Lyon, with 1.1 million inhabitants, is the third largest city in France after Paris and Marseille. It is a lively industrial centre. Lyon lies at the intersection of many transport routes and at the fluence of Rhone and Saone. Like all large cities, Lyon is attempting to alleviate inner city traffic problems by constructing a metro. Metro construction in Lyon began with tunnels built by cut and cover methods along the streets. Deep diaphram walls, which were back anchored and toed into imperveous strata, formed the excavation walls. It is a very economic and simple method. However during the construction period, it has the disavantage of strangling urban life for several years. It is therefore increasingly being replaced by subsurface tunnelling methods. As it was decided to build the metro tunnel between the Guillotiere and St. Jean stations, and thus cross under the Rhone and Saone, the client, Semaly, put the contract out for a competitive tender in which the general parameters were defined. Line, level and construction method were left to the contractor. There was an extensive examination of the tenders, during which reference projects from competitors in Japan were visited, as well as in Germany. Finally the consortium of Dragages, Campenon Bernard, Colas and Hochtief was awarded the contract to drive this tunnel section with an hydro-shield and an extruded steel fibre concrete lining, a Hochtief design.

Jan 1, 1987

By G. E. McCormack

The Development of Water Gel Explosives Water gels are the most recent development in the evolution of commercial explosives. They are replacing dynamite, having proven themselves to be excellent alternatives to this standard explosive. Water gels have steadily displaced dynamite over the past two decades. In 1959, they accounted for only 1 percent of the market they share with dynamite. By 1965, the share taken by water gels had grown to 21 percent. In 1970, it was more than 40 percent, and today it is nearly 70 percent. Black powder, the first widely used explosive, revolutionized mining and quarrying in its day. However, when nitroglycerin dynamite became available about a century ago, it rapidly displaced black powder because it provided greater energy for a given weight, much higher velocity for better rock shattering performance, and water resistance for easy use in wet conditions. During the past 50 years, ammonium nitrate has played a dramatically increasing role in explosives. First, it was used as an ingredient in dynamite, and then as the main component in nitrocarbonitrate blasting agents. About a quarter of a century ago, it began to find use in a simple and inexpensive mixture with fuel oil that has revolutionized the explosives industry and today fills about 80 percent of the requirements for explosives in the U.S., and certainly the bulk of blasting requirements worldwide. Water gels and dynamites share the remaining 20 percent. Water gel explosives based on ammonium nitrate have also been developed during the past quarter century. These explosives contain

Jan 1, 1979

By Jacob Feld

Introduction The best way to eliminate the possibility of rapid excavation in tunnel work is to start an argument between Owner Engineer and Contractor. And arguments are readily started when work is progressed without a frank open agreement on the rules of the game. Fifty years ago a tunnel contractor took a job to excavate and line a tunnel, providing all labor and materials under the guidance and continuous instruction of the Engineer who provided all survey work, checked each new heading and set the lines for the next round of drill holes, usually designed and ordered protective measures, kept record of progress and controlled payment for the work. In my first job in a tunnel, muck cars were loaded by hand and hauled by donkeys. Progress was, at today's criteria, not rapid. The Contractor or in the case of a large concern, his executive field representative was always at the site, knew most of his men by name, and there was a mutual feeling of respect between him and the Engineer in charge of the work. Misunderstandings were cleared up when they came up, expeditiously and fairly, even though satisfaction was not always expressed. The Owner came for the ground breaking and usually for the holing through shot. The Owner had full reliance on the Engineer's ability and integrity. The Engineer recognized the Contractor's expertise in being able to man the job and produce results.

Jan 1, 1974

By A. Pratt, G. Deschênes

This paper quantifies the detrimental effects of pyrite and stibnite on gold leaching kinetics. Means to reduce the effect of these minerals by addition of lead nitrate and oxygen are presented. A significant retarding effect was observed when the pyrite concentration was 20%. A pretreatment with lead nitrate reduced the extent of gold surface coating by Ag, Fe and S. Stibnite, at a concentration as low as 20 ppm, significantly affected the gold leaching kinetics through forming a passivating film of Sb(V) oxide possibly Sb2O5. The most practical way to alleviate the effect of stibnite is to leach the materials at a moderate pH with addition of lead nitrate. A low temperature reduced the efficiency of lead nitrate to counteract the effect of stibnite. The increase of dissolved oxygen is not favourable to alleviate the coating of stibnite on gold.

Jan 1, 2004

By Hal McVey

Introduction The role of marketing in the minerals and mining industry takes on different degrees of importance depending on the commodity, but nowhere are sales and marketing more important than in industrial minerals. This article compares industrial minerals marketing with the marketing of other mining and mineral products. Marketing in Mining Some broad generalizations on the marketing of industrial minerals in relation to other mineral products can be made without getting bogged down with exceptions to generalizations. Two totally different areas of mineral production are crude oil and natural gas, and metals, including ores and concentrates. Although these commodities are the basis for two completely different industries, they share two things in common from a marketing standpoint: • Their value per unit volume is usually high enough so that they can be transported great distances. • Their specifications are readily definable and, therefore, the quality of a standard product from a production run can be communicated by stating certain chemical and physical features. This permits sales to be consummated by telephone, telex, and letter, without the need to pretest the products under use conditions. In regard to the first item, industrial minerals, as opposed to oil, gas, and metals, are in most instances site specific. Location of the point of production in relation to the point of use is of paramount importance based on a generally lower unit to volume value. This means that transportation is a major factor, with the cost of getting the mineral to market commonly exceeding its f.o.b. value. Coal marketing has many characteristics in common with industrial minerals. Coal sales can es-

Jan 11, 1983

By Yutaka Mochida

OUTLINE Beginning in 1946, a careful geological survey was made of the Tsugaru Straits. In 1964, excavation of the exploratory tunnels were started to observe the characteristics of faults and rock formation directly, and to study construction methods of excavation and sealing water inflow. In March 1971, the investigation stages were over, and in April 1971, the construction project was authorized from the government. The geological features in the straits may be divided into three broad classes. One third consists of andesite on Honshu side. The other two thirds consists of tuff. The middle of the straits consists of tuff, so-called Kuromatsunai-layers. On Hokkaido side, it consists of tuff, called as Kunnui-layers. There are nine noteworthy faults on the route. Prior to the excavation of the main tunnel, the horizontal pilot tunnels and service tunnels are made. Exploratory borings are taken to confirm the geological conditions and the presence of gushing water. Groutings for sealing water inflow are carried out when necessary. In geologically bad conditioned sections such as disintegrated or fractured zones, special methods are applied. In geologically good zones, the tunnels are bored through using the same methods as for a mountain tunnel driving. The pilot tunnel being constructed at the sea bottom is under direct control of the Japan Railway Construction Public Corporation. The service tunnel and the main tunnel are being excavated by contractors.

Jan 1, 1981

By D. D. Snyder, J. D. Bode, F. T. King

INTRODUCTION Only in recent years have the environmental hazards associated with mining and tunneling operations been fully acknowledged and determined remedial action undertaken. The nature of these excavation operations leads to a wide diversity of hazards spanning mechanical, electrical, chemical, environmental, and physiological. The most insidious of these are unquestionably the environmental ones which have the greatest long-term effect and are the most difficult to pinpoint and monitor. It is the atmospheric contaminants that lead to a significantly greater illness and mortality rate among miners. Dust is the most prevalent, hence most important of the atmospheric contaminants. Respirable particles lead to diseases characteristic of many mining operations: coal workers pneumoconiosis, asbestiosis, silicosis, talcosis, anthrocosis, etc. But toxic and suffocating gases can be equally insidious and the most innocuous pollutant, methane, leads to the most imminently disastrous results of all - explosion and fire. This means that truly effective monitoring of the environmental hazards in tunneling cannot be limited to a few simple standard check measurements. It must include the most precise measurements we can make for specific, documented hazards and even for factors, such as noise and heat stress, not immediately obvious as hazards. The Federal Metal and Nonmetallic Mine Safety Act and more recent Occupational Safety and Health Administration standards are clearly designed to match such effective monitoring. We must, therefore, consider not only presently available monitoring instruments and those currently under develop-

Jan 1, 1997

By R. J. Reuss

Mina Maria is a high-grade, underground copper mine located in the Cananea district of Sonora, Mexico. The ore body is a massive sulfide breccia located in mountainous terrain. A major highway and an electric transmission line pass directly over the near-surface ore body. The mine is operated by Minera Maria SA de CV, a joint venture company that is 51 % owned by Empresas Frisco SA de CV and 49% by Cominco Resources International Ltd. Empresas Frisco is the operating partner. Production began in October 1990. The mining method used is undercut and fill. A continuous miner and a single-boom, hydraulic jumbo mine the ore. Backfill is a weakly cemented sand-gravel mixture that is pneumatically placed. The ore is treated by conventional crushing, milling and flotation. The Maria deposit is located about 40 km (25 miles) south of the Sonora-Arizona border and 11km (7 miles) northwest the city of Cananea and the Cananea Mine. The mine portal, at an elevation of 1780m (5840 ft), is on the east side of an important drainage divide. The mill site is situated about 800 m (2625 ft) northwest of the mine on the northwest side of the drainage divide where the drainage is more favorable. Its elevation is 1860 m (6100 ft) (Fig. 1).

Jan 1, 1992

By K. Chandrasekaran

Carbon-in-leach (CIL) is conventionally used in gold processing operations when preg robbing components are present in the ore. The CIL process is becoming attractive even in other situations when preg robbing is not a factor. This article discusses the situations in which the CIL circuit can be applied. The results of leach-carbon-in-pulp (CIP) and CIL circuits at Newmont Gold's Mill No. 2, No. 4 and No. 5 are presented for comparison: Mill No. 4 was initially designed for a throughput of 4.1 kt/d (4500 stpd). It is presently operating at an average throughput of 6.6 kt/d (7300 stpd) without significant changes to the original design. The design considerations of the Mill No. 4 CIL circuit are discussed. The design of any processing facility represents a series of decisions. The final design options should ultimately be resolved based on economic as well as technical considerations. Every design decision represents some sort of compromise. From the designer's view point, these decisions are made with the conviction that the final product represents the most prudent long-term expenditure. The design throughput rate is a decision reflecting a maximum return for the capital and operating costs that the plant will incur over the life of the mineral resource. The result is a plant that is not operator proof or maintenance free because it would be too costly to build. At some point, the incremental increase in the level of capital expenditure would not adequately compensate for the lower

Jan 1, 1991

By Harold G. Arthur

INTRODUCTION Stillwater Tunnel construction is scheduled to start in the spring of 1973. The tunnel will be the site of an extensive program in rapid excavation research. This paper presents a progress report regarding our plans and relates the tentative decisions which have been made on how to carry out the research effort. The details are subject to revision as more input is obtained from other Government agencies interested in tunnel construction and from experts in industry and educational institutions. The objective of the research program is to bring about faster, less costly tunnel construction. This objective will be pursued through the development, improvement, and evaluation of various construction systems and investigative techniques. The need for this kind of program was recognized by the National Research Council, in its authoritative report "Rapid Excavation - Significance, Needs, Opportunities." (1) The Council advocated a federally funded $200 million, 10-year program to help meet the $69 billion market it expects in underground excavation between 1970 and 1990. The significance of tunnel construction to Reclamation is made clear by statistics of its tunneling experience and outlook. Reclamation has constructed 174 water conveyance tunnels totaling over 190 miles, Six tunnels are presently under construction which have a combined length of about 27 miles. There are on the books nine authorized, but unfunded tunnel projects totaling another 70 miles in length. Many more miles of tunnels are included in programs in various stages of investigation.

Jan 1, 1997

By Prakash M. . P. E. Donde

1. INTRODUCTION The Washington Metropolitan Area Transit Authority (WMATA) has often taken a leading role in introducing innovative construction technologies to build its transit system. Most recently, Contract Section E-5a, which included Fort Totten Station and Tunnels was constructed utilizing the New Austrian Tunneling Method (NATM) in soft ground. Along with the station and tunnels, two permanent shafts were also constructed in soft ground employing the NATM technique. This project is located within the District of Columbia on the Greenbelt Route. The subject of this paper is to discuss the unique method of construction of these two shafts, and explore the benefits of applying the NATM technique to the construction of deep shafts. The design of the shafts was performed jointly by Jenny Engineering Corporation of Springfield, New Jersey, and Mayreder Consult of Linz, Austria. The designers also provided construction support services and a resident NATM expert at the site during construction. The construction of the project started in April 1988 by a joint venture of Mergentime Corporation and H. T. Construction, a subsidiary of Hochtief Company from Germany. This $48.7 million construction project has been completed. 2. SUBSURFACE CONDITIONS The two NATM shafts are located primarily in Cretaceous-age deposits that are over 100 million years old. These deposits are intermixed and lenticular in nature

Jan 1, 1993