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By R. E. Mason

Shotcrete has been used for approximately 20 years to facilitate tunnel excavation through poor ground. Early examples of such usage in North America include the recuperation of the Granduc Mines access tunnel in Northern British Columbia, and similar work performed in the Carley V. Porter and Big Walker Tunnels in the United States. Mining companies such as Craigmont Mines in B.C. and Hecla Mines have used shotcrete in their workings for the past ten years. Shotcrete is now a widely utilized fool in the mining and tunnel construction industries in North America, but the accumulated experience is too limited for many to fully appreciate the capability of shotcrete to control ground movements and to understand the limitations of this tool. It is common, for instance, to use shotcrete to "bridge the gap" between rock bolt-supported and steel-rib supported ground and to avoid the use of shotcrete in water-bearing ground. Shotcrete can, and has been, used economically and practically under most severe ground conditions.

Jan 1, 1976

By W. G. Lacy

Anticipation of problems and the adoption of corrective measures in the design of engineering structures, establishment of pertinent building codes, and urban planning and zoning to obtain optimum land usage and conservation of natural resources demands a thorough understanding of geological conditions of a developing urban area. In the and to semi-arid southwestern United States erosional and depositional processes result in special situations that require special precautions in building practices. A series of studies currently underway in the Tucson area prompted by foundation failures and breaking, of buried service lines serve to illustrate some of these relationships between the geological environment and history, and engineering problems.

Jan 1, 1963

By A. J. Erickson

In mid 1970, Park City Ventures, a Utah partnership of ASARCO and TAC, initiated a six phase exploration and development program in the Park City District, Utah. Geologic studies had delineated a number of exploration tar¬gets in several areas of the district. Discovery of ore in any of the target areas and continued favorable down dip development below then productive ore bodies would allow for reserve expansion and mill construction. The targets were: Mississippian Humbug Formation replacement mineralization below productive ore bodies on the east flank of the Park City Anticline; Humbug replacement mineralization in an unexplored fault block in the footwall of the Hawkeye structure on the east flank of the anticline; vein and replacement mineralization along the Silver Fissure; potentially higher grade Humbug replacement mineralization in a theorized structural block on the west flank of the anticline beneath the Ontario Vein; Permian Park City Formation replacement mineralization in the West End Shaft Area of the Silver King mine; vein mineralization along the Back Vein in the Judge Mine. Chilean Nationalization in 1971 resulted in a 30% budget cutback. The Judge and Silver King Projects were suspended. In spite of the cutback additional reserves were developed below the Humbug East Flank ore bodies; a major zone of ore grade mineralization was discovered along the Silver Fissure; five new ore bodies were found in the Humbug, and Doughnut Formations on the west flank of the anticline beneath the Ontario Vein. First concentrates were shipped from a new mill in May 1975.

Jan 1, 1976

By Robert Walker

The win theme of this session is Unique Material Handing Systems. The theme was selected because of two major factors. 1. Accomplishments of unique character manage to attract interest regardless of their age. 2. There is much to be learned from pioneering efforts of the past as they are the stepping stones to technological development. Thus, 2-1/2 years after completion, the engineering feat of Oroville Dam still looms large let us take a close look at this project to see what made it unique. To begin with, it established a number of firsts: At 770 feet it was the highest earth fill dam in the world. At $121 million dollars, it was the largest ever United States construction project (Civil). At 80 million cubic yards it had the largest earth volume of any dam in the world. The extensive use of belt conveyors for this application had never before been tried. The use of a high capacity bucket wheel-excavator with shiftable belt conveyors had never before been utilized as a con¬tractor's tool. The principal of the "integral train" was applied most effectively whereby up to 220,000 tons of material-was transported daily some 14 miles. To achieve optimum economics a number of technical breakthroughs were necessary. The suppliers of major commercial components worked hand-in-hand with system engineers to develop new machinery necessary for the highly mobile characteristics of the systems, viz., single pulley drives delivering 2000 horsepower, 1000 horsepower right-angle shaft-mounted reducers, across the line starting of 1000 horsepower squirrel cage motors, 10 miles of steel chord conveyor belts with belt tensions up to 150,000 pounds, aircraft-type disc brakes, hydraulic take-ups, train loading at a rate of 25,000 tons per hour, automatic train indexing for rotary dumping at 10,000 tons per hour, roll-over car dumping without uncoupling cars, shifting 7500 ft. long conveyors up to 300 feet laterally without disassembly. These are some of the superlatives that have made the Oroville Dam project unique. The measure of its success is demonstrated by the results.

Jan 1, 1970

By Paul F. Thiele

The mining industry of Georgia, while not as large as in some other states, is still an important part of the economy. Total value of mineral production in 1966 was $148.6 million.l/ Clays and stone produced the most income, Other minerals included sand and gravel, iron ore, mica, talc, barite, bauxite, cement, feldspar, kyanite, peat, and rare-earth metals, titanium and zircon concentrates. Georgia ranks first among the states in production of kaolin, second in fuller's earth and rare-earth concentrates, third in bauxite and kyanite, fourth in barite and ilmenite, and fifth in feldspar. It is quite likely that phosphates will one day be mined in the south eastern part: of the state, and that alumina will be produced from the extensive kaolin deposits in the central part of the state.

Jan 1, 1968

By P. Stanley Jacobsen, Hemant B. Gala, Richard E. Hucko

Coal is the nation's most abundant fossil energy resource. However, its use is limited because of the nature and amount of associated impurities, such as mineral matter, sulfur, trace elements, and moisture. The moderate-to high- sulfur content of many U.S. coals is of particular concern as current and newer, potentially more stringent, regulations require reduction in sulfur oxide emissions. Release of particulates, NOx, and other pollutants during the coal-use cycle is also of concern. The current practice of controlling sulfur oxide emissions in the major steps of the coal- use cycle is limited mainly to coal preparation by physical beneficiation and, to a smaller extent, to post-utilization cleanup (flue gas desulfurization). Approximately two-thirds of the coal from states east of the Mississippi river is physically cleaned, whereas only 15% to 20% of the operating boilers in the utility industry are equipped with scrubbers to desulfurize the flue gas (Henzel, 1988). Physical beneficiation methods can be very effective in removing mineral matter, including pyritic sulfur, from coal. These processes take advantage of the differences in physical proper- ties between coal and mineral matter to achieve the separation. In a typical physical cleaning operation, raw coal is crushed to about a 50-mm (2-inch) top size. It is then screened into coarse, intermediate, and fine sizes. Crushing the coal liberates some of the ash-forming minerals, including a portion of the sulfur that is not chemically bound to the coal. The per- centage of impurities freed from the coal matrix generally increases as the coal particle size decreases. The coarse- and intermediate-sized coals are typically subjected to a cleaning pro- cess based on differences in specific gravity between coal particles and the associated impurities. Such cleaning processes used include jigs, dense-medium baths, cyclone systems, and concentrating tables. The fine-sized (typically less than 0.5-mm) coal, if beneficiated, is typically cleaned using a froth flotation technique based on the differences in surface proper- ties between coal and its associated impurities. At fine sizes, greater cleaning potential exists because a greater portion of the impurities is released from the coal matrix. However, this potential is not fully realized owing to inefficiencies in separating fine particles using state- of-the-art flotation technology. Overall, current commercial coal preparation processes are estimated to remove up to 60% of the ash and 10% to 30% of the sulfur, depending on the coal characteristics, with product weight recoveries rang- ing from about 60% to 90% and thermal recoveries of about 85% to 98% (Versar, 1985; Science Applications International Corporation, 1987; Hoffman- Muntner Corporation, 1978). For many U.S. coals, grinding to sizes finer than those used in current coal preparation plants is required to liberate most of the physically bound impurities from the coal matrix. As noted, conventional coal-cleaning methods are not very effective at these fine sizes. Accordingly, the expanded use of domestic coal requires the development of advanced coal cleaning technologies that can provide economic performance while reducing environmental impacts. Program Goals and Objectives The overall goal of the U.S. Department of Energy (D0E)'s Coal Preparation Program is to provide the scientific and engineering knowledge base that industry can utilize to produce economically competitive and environmentally acceptable clean-coal products for introduction as market conditions warrant. The coal preparation process(es) should remove undesirable components from coal and improve its handling characteristics, thus making the product coal technically, as well as economically, viable as a competitor with petroleum-derived fuels and natural gas, and with alternative environmental control technologies. The coal preparation process must be applicable to a wide variety of bituminous and low-rank coals. The cleaning process should reduce the variability among clean-coal products from various raw coals, thus significantly increasing the range of potential end uses for each raw coal. To the extent that deeply cleaned coal products have greatly reduced levels of

Jan 1, 1988

By C. I. Everson

The Elkhorn mining district is located 35 kilometers southeast of Helena, Montana, on the southeast edge of the Boulder Batholith. Geologically the district consists of a folded sequence of Paleozoic limestones and shales which have been thermally metamorphosed and altered by monzonite to diorite intrusives related to the Cretaceous Boulder Batholith. For the most part, the skarns are associated with metasomatic: replacement of calc-silicate hornfels, diorite and marble by iron rich, dark green pyroxene, garnet, sulfides, the district contains excess of 30,000 Kg.

Jan 1, 1992

By K. Takahashi

The methyl stretching vibrations for a series of normal and iso xanthates were determined using an infrared spectrophotometer, and the results were compared with the published information on the corresponding alcohols. The frequency shifts of methyl stretching vibrations may be attributed to the inductive effect of polar groups. The hydrogens in the shorter chain alkyl groups are somewhat polar and can be expected to interact with water molecules by hydrogen bonding. Contact angle, surface tension lowering, and solubility appear to be related to the induced polarity of the alkyl groups.

Jan 1, 1968

By Paul K. Edwards

The forces of nature have concentrated sand at various geographical locations that are being mined and processed for a large variety of industrial uses. While most operations serve a number of industries, this paper deals only with the foundry requirements. The forces that have decomposed a source rock, transported this material and redeposited it, have created two general types of sand. These types are classified as the (1) Lake and Bank Sands and (2) Silica Sands. The Lake and Bank sands will contain 92 to 94% Sio2 while silica sands are in excess of 98.5% Si02 and most of the producers wash these sands to up grade their products to 99.5% or better. Included in the Lake and Bank sand would be the river sands that are used primarily for construction purposes. The Foundry Industry is broken down into three types of castings : 1. Grey Iron Foundries The grey iron castings largest market is the automotive industry in Ohio, Northern Kentucky, Indiana, Illinois and Michigan. These castings are poured at temperatures ranging from 2400° to 2700°F. The Silica Sands or the Lake and Bank Sands will satisfy the requirements of the grey iron castings. There are 2 ½ to three million tons per year shipped from the state of Michigan far grey iron castings by the Lake and Bank Sand Producers.

Jan 1, 1974

By M. S. Klima

Proper analysis of washability data can lead to the development of a maximum yield coal preparation plant flow sheet. Simulations, as simple as spreadsheet mass and water balancing, are important in examining yield maximization and middlings liberation. Key to such attribute tracking flow sheet simulations is the distribution model, expressing the probability of a species reporting to the product stream. There are many such models in the literature. This paper examines a functional form that can represent or fit most of the proposed distribution functions.

Jan 1, 1997

By John Duff Erickson

Determination of the final pit limits of an open pit copper mine is a problem that has far reaching effects on the life, profitability and operation of a mine. The solution to this problem requires that all of the significant variables affecting the final pit limits be considered together with corporate objectives as the guiding principle. This paper discusses the use of these variables and how they should be applied to plan the future of a mine. The objectives of a final pit plan; are determination of the extent and location of ore reserves, the allowable stripping to be accomplished to uncover the ore, the final pit surface intercept, final pit topography and the contained metal values in both ore and waste. The objectives of the plan must be consistent with corporate objectives as they pertain to profit, future investment in the mine, return on investment, alternative investments, conservation and perpetuation of the corporate entity. The subject will be treated in three parts: economic considerations, effect of leaching and pit design technique. At the outset, it is assumed; that the extent of and metal values in the mineralized area to be considered have been reasonably defined by development drilling and sampling.

Jan 1, 1968

By C. G. Anderson

Historically, the treatment of orebodies for recovery of valuable constituents presents many processing challenges. In a time of heightened environmental awareness, the constraints placed on processing complex orebodies are becoming more and more pronounced. As such, established technologies are limited in their ability to fill the needs of these emerging sources of raw materials. A prime example of this is in processing PGMs from primary sources. Normally, this type of material is found in a nickel-copper-iron sulfide matrix. Typically, these materials are processed by established pyrometallurgical means. However, other options should be considered. Hydrometallurgical processes are available which offer advantages over pyrometallurgical methods. One of these is the nitrogen species catalyzed sulfuric acid pressure leach used industrially by Sunshine Mining and Refining Company. In 1990, laboratory work was undertaken in cooperation with Stillwater Mining Company to test PGM matte materials from the Columbus, Montana smelter. The initial results were very positive, and they led to a design to recover PGMs in a high grade residue and to recover nickel and copper as valuable products. Handling the iron and other wastes in an environmentally safe manner was also successfully investigated.

Jan 1, 1995

By Daniel T. Hegyan

The employment of continuous rotary vacuum disc filters to filter refuse from the fine coal washing circuits has been increasing as it has become more important to close the water circuits and eliminate sludge holding ponds. This paper will discuss our past experience filtering refuse, effects of solids concentration in the filter feed, use of polymer flocculation aids, effect of flocculation devices, and effects of particle size and ash content on the filtration rate. Detailed tests were performed on existing installations utilizing coal refuse filters to determine optimum flocculant dosage, solids concentration, and disc rotation speed to form a dischargeable cake. Information was also obtained showing effect of flocculant addition on the moisture of the filter cake. Our test work has shown that the continuous filtration dry cake rates for fine coal refuse correlates very well with the data developed and presented by Silverblatt and Dahlstrom1 except that the curves have moved up the scale by use of polymer flocculant additions. These polymers were not available at that writing. Finally, our tests also confirmed the general premise stated by S. K. Mishra2 that controlled additions of polymer flocculants will reduce filter refuse cake moistures somewhat.

Jan 1, 1974

By Robert A. Metz

During the past decade we have witnessed spectacular improvements in productivity of open pit mining equipment. Thousand-horsepower engines, 200-ton trucks and 15-yard electric shovels, which such a short time ago were just dreams on a drawing board, are now realities. More productive equipment and metal shortages have encouraged increased production at existing mines and the development of new larger tonnage operations. Operators and engineers have been able to employ computers and various other types of automation to "stay on top of things". The mine geologist, however, is merely faced with a bigger and more rapidly changing pit to pick in. Keeping geologic information current in these mines presents entirely new problems to mine geological staffs. To obtain adequate geologic information on the developing orebody requires enlargement of the staff to share the work load or revision of methods in keeping with the times. The former has the disadvantage of loss of the comprehensive knowledge of the pit that a chief geologist likes to have, not to mention management's usual lack of enthusiasm for force increases.

Jan 1, 1970

By C. D. Keith

Erie Mining Company, a pioneer in the iron ore pelletizing industry, has continued to develop methods and equipment to improve cost and quality. Under the management of Pickands Mather & Co., this property, owned by Bethlehem Steel Corporation, Youngstown Sheet and Tube Company, Steel Company of Canada, Ltd., and Interlake, Inc., has initiated a number of operating improvements for the taconite industry. One of the most noteworthy of these, which is applicable to the entire mineral industry, is the principle of fine screening with rappers (FSR). Erie's original efforts in the field of fine screening, which date back to 1961, were described in the April 1967 issue of the MINING ENGINEERING magazine. In that same month, Erie placed into operation a full scale PSR and regrind plant addition, capable of processing 10.3 million long tons of iron ore concentrates, produced by conventional taconite grinding, classification, and magnetic separation methods. Since this first successful commercial operation of the PSR principle et Erie, it has been applied in eight other iron ore beneficiation plants end is being tested by other U.S. and foreign companies. In addition to the use of PSR units at Erie Mining Company, Pickands Mather has applied PSR to other of its managed properties end to projects under development. This paper covers these applications as well as a now application at Erie Mining Company.

Jan 1, 1971

By Fred H. Lightner

The feasibility evaluation of the Borealis project of Houston International Minerals Corporation (HIMCO) was initiated in October of 1980. The operation of the Borealis Mine and heap leaching plant began in late 1981. In order to achieve the rapid development schedule several items were necessary: 1) Pre-planning of environmental requirements and early study of key issues. 2) Adoption of conservative design criteria. 3) Coordination and cooperation between HIMCO and regulatory agencies. 4) Adoption of specialized engineering and construction procedures. 5) Careful evaluation of owner project management philosophy.

Jan 1, 1982

By I. E. Odom

A study was made of the physical and chemical nature of silica minerals found as natural impurities in bentonites and montmorillonitic Fuller&apos;s earth clay products as well as in <10 micron dust from eight processing plants. The results show that the silica minerals present in these clay materials are totally encapsulated or encased in clay. No "free" silica minerals could be observed in SEM images of either granular or powder products or in dust samples collected for MSHA crystalline silica analysis. Silica minerals, such as quartz, are identifiable by SEM and EDS analysis only after removing the clay coatings by vigorous washing. After washing it can be observed that all crystalline quartz grains also have diagenetic overgrowths of what is probably opaline silica. The clay and opaline silica encapsulation of quartz plus the strongly hydro scopic nature of montmorillonite are believed to be responsible for there not being a single confirmed case of silicosis among workers in the subject plants after more than 65 years of production.

Jan 1, 1996

By O. R. Swendseid

The Mountain Con mine is a relatively old, deep mine located in Butte, Montana. Operations at this property through the present shaft were started before the turn of the century. As mining progressed to depth, increasing demand for ventilation facilities and changing mining conditions made it convenient to convert some nearby shafts to airways. The fact that these openings had not been originally planned for use as airways made it necessary in some instances to utilize long and inefficient already-estab¬lished entries to service working areas. This situation existed in the Lexington fresh air system. The Lexington system consists of a vertical, 3-compartment shaft extending from surface to the 3200 level and a series of 2-compartment air raises and old horizontal-haulage openings extending into a mining area several thousand feet west of the Lexington shaft between the 3900 level and the 4200 level. Because of restrictions and high resistance in the portion of the system between the bottom of the Lexington shaft on the 3200 and the mining area on the 3900, the capacity of this system is only 85,000 cubic feet of air per minute. It was calculated that the capacity of the system could be in¬creased to meet the demands of the current mining program in this section of the mine by utilizing a single, straight, horizontal air course on the 3200 and by driving an inclined air raise 740 feet long between the 3900 and the 3200.

Jan 1, 1967

By Ulises Deveze T.

The coal company Minerales Monclova, S.A. (MIMOSA), the owner of the Mimosa R Line, is a subsidiary company of Altos Hornos de Mexico, S.A., the largest steel plant in Mexico with an annual capacity of 2.5 million metric tons of steel ingots. The raw material&apos;s which are used in the steel plant are provided by the following companies: La Perla Minas de Fierro, S.A., iron ore; Cia. Minera de Guadalupe, S.A., Cia. Carbonera La Sauceda, S.A. Cia. Minera La Florida, S.A., and Minerales Monclova, S.A., which provide the coal used for coke, and altogether constitute the industrial group AHMSA. The coal property of Minerales Monclova, S.A. is located in the Sabinas coal area in the northwestern part of the Sabinas basin.

Jan 1, 1974

By Clayton J. Parr

Introduction This chapter contains brief discussions of various environmental protection requirements that relate to underground mining operations. Environmental disturbances at an underground mining operation can result from subsidence; water discharges; waste dumps; construction and operation of access roads and utility lines; construction and operation of surface facilities such as maintenance shops, bathhouses, and storage yards; and emanation of dust and noise from surface crushers. Construction and operation of a concentrator or washing plant may result in the emission of air pollutants, the discharge of water pollutants, the creation of noise, and disturbance of the surface. Tailings ponds can be the source of fugitive dust.1 This chapter is not intended to provide a detailed discussion and analysis of laws and regulations dealing with environmental protection. Rather, its purpose is to provide the engineer with a basic awareness of the existence and nature of such laws and regulations, as well as the procedural requirements that must be followed in complying with them. The body of law relating to environmental protection has grow" very rapidly and should continue to do to for some time. Because many of the laws have been enacted recently, numerous court decisions are being rendered to resolve disputes over their interpretation. Hence, the reader is cautioned to be alert for subsequent modifications of statutes and regulations, and new case law. Rules and regulations pertaining to environmental protection are implemented at all governmental levels. The most widely known laws are those enacted by the federal government that have nationwide applicability. However, separate requirements exist in each state, county, and municipality. Because of their general applicability, federal laws are discussed most extensively in this chapter. Ownership of the property is the most significant factor considered in ascertaining what rules govern the conduct of an operation thereon. If the land is held under lease, reference to the lease terms must be made in the first instance to determine what obligations must be met in order to prevent default and possible loss of the property. If the land is held under a lease from the federal government, the operator is subject not only to compliance with the lease terms, but also to a large body of laws and administrative regulations that pertain generally to the conduct of mining operations on land held under federal leases. Although operations on unpatented mining claims, the legal title to which remains in the federal government, are not subject to the same rules and regulations that are applicable to operations conducted pursuant to federal leases or permits, they soon will be governed by a special set of regulations that provide for protection of surface resource.2 Operations conducted on lands leased from a state usually are subject to numerous environmental protection requirements specified in the lease terms, in addition to rules and regulations promulgated by the state agency having jurisdiction over mining on state lands. Operations conducted on privately held lands are subject to fewer such requirements. Leases from private parties sometimes have environmental protection and reclamation requirements written into them, but generally to a far lesser extent than governmental leases. Operations conducted on properties owned by the operator are subject only to those laws and regulations that have general applicability without regard to land ownership. COAL SURFACE MINING CONTROL AND RECLAMATION ACT OF 1977 Introduction On Aug. 3, 1977, the Federal Surface Mining Control and Reclamation Act of 1977 was signed into law.3 It governs coal-mine operations on private lands, as well as on public lands. The Act is pervasive in its scope and is extremely long and complex. The basic purpose of the Act is to control and minimize the environmental effects of surface coal mining. Surface coal-mining operations are defined as activities conducted on the surface of lands in connection with a surface coal mine and surface impacts incident to an underground coal mine.4 The Act is administered by the Secretary of the Interior through a new agency named the Office of Surface Mining Reclamation and Enforcement.5 The Act contains detailed environmental protection standards and reclamation requirements, and it establishes a permit system for all surface coal-mining operations. Mining in certain areas and under ceri-in conditions is restricted or prohibited, and a mechanism for enforcement by the states is provided. Stiff penalties are provided in the event of noncompliance. Implementation Schedule Nonfederal Lands: As required by Section 501 of the Act, interim regulations setting mining and reclamation performance standards based on and incorporating standards set out in Section 502(c) were adopted effective Dec. 13, 1977.6 They will. be incorporated as amendments to Chapter VII of Title 30, Code of Federal Regulations. Permanent regulatory procedures for surface coal-mining and reclamation operations performance standards, which were directed to be promulgated by Aug. 3, 1978, were published in proposed form on Sept. 10, 1978. 7 They govern surface coal-mining operations in any state until a permanent state or federal program is adopted. As of Feb. 3, 1978, all new operations, and as of May 3, 1978, all existing surface coal-mining operations, on lands on which such operations are regulated by a

Jan 1, 1982