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By R. A. Pond

Two 6.17 m (20 ft 3 in.) diameter raises, concrete-lined to 5.49 m (18 ft) inside diameter, were completed in 1978 at the Monterey Coal Company Number One Mine near Carlinville, Illinois, by Frontier-Kemper Constructors. These two raises are the largest in cross-section yet completed by full-face upreaming, and the success of this project is expected to increase the application of raise-boring to coal mine shaft construction. WHY 6.17 M (20 FT) DIAMETER ? Raise boring is well accepted in the metal mining industry for a variety of applications, and is gaining in acceptance in the civil works construction industry. The use of raise boring to construct vertical openings for coal mines has not been as widely accepted, even though coal mining requires, per mine, the greatest number of openings to the surface of any underground activity. Several factors have influenced the low utilization of raise boring in coal mining: 1. Coal mine shafts must often be of large diameter to pass the required high volumes of ventilation air at acceptably low water gage pressures. Cross-sectional areas of finished shafts exceeding 23.23 sq m (250 sq ft) are common. 2. The life of ventilation shafts is comparatively long, and the typical sedimentary strata overlying coal seams normally require that the shafts be lined. Shafts on the intake ventilation circuit must have permanent water-tight linings. 3. Unconsolidated overburden at the surface is often thick, and as reaming cannot be safely utilized in unconsolidated material,

Jan 1, 1979

By J. N. Adamson

The Alcan Smelter project at Lynemouth on the Northumbrian coast draws cooling water for the power station through shafts and tunnels from the North Sea. The sea at this part of the coast is frequently very rough and even in calm weather the coastal currents are strong. The adjacent coal mine makes use of these currents to disperse colliery waste and discharges into the sea some thirty thousand tons each week. In consequence the sea bed is continuously shifting and the sea is black and turbid. Construction of sea shafts under these conditions presents difficulties as drilling from a floating vessel is hazardous and sea bed activity of divers is greatly hindered by the entire absence of visibility. After considering several alternatives a method of construction was agreed with the Consultants in which the drilling and also the lining of the shaft would be completed in sequence from an eight legged work barge (GEM 126). Each shaft would be drilled to full depth and a steel cylinder, with its ends closed temporarily, would be lowered into the hole and grouted into the formation to form a full-length permanent lining. The bell mouth for each shaft would be constructed in advance to form part of the cylindrical casing. On interception of the shaft by its appropriate tunnel the lower end of the cylindrical casing would be cut away and the internal walling of the shaft installed from below. After completion of construction the shafts and tunnels would be flooded and the bell mouth sealing covers removed by divers.

Jan 1, 1997

By P. J. Macbeth, R. F. Overmyer, K. K. Nielson

INTRODUCTION Over the past several years, Ford, Bacon & Davis Utah Inc. (FB&DU) has been involved in research, development, and engineering activities concerning uranium mill tailings; specifically of interest in this paper are efforts in radon gas exhalation and surface flux attenuation measurements, environmental influences on radon fluxes, and basic research into radon gas behavior. Our projects have included measurements of effectiveness of specific cover material in attenuating radon surface fluxes from mill tailings, characterization of the parameters in cover materials and tailings that influence radon exhalation, long-term tailings stabilization planning, determination of the effects of moisture on radon emanation and diffusion from ores, and determinations of baseline radon fluxes. Our efforts have been sponsored by U.S. Department of Energy, the U.S. Nuclear Regulatory Commission, Tennessee Valley Authority, the commercial uranium industry, and we are presently engaged in efforts for the U.S. Bureau of Mines. Much of the material presented in this paper is taken from our published reports on radon flux attenuation and tailings stabilization (Macbeth et al., 1978; Nielson et al., 1980; Rogers et_ al., 1980; Thamer et al al., 1980). CHARACTERIZATION OF RADON GAS EXHALATION One dimensional diffusion theory based on Fick's laws is the basis for the modeling of radon gas migration through large quantities of porous tailings and cover materials applied over the large areas of tailings piles. Fick's first law relates the gaseous concentration gradients to the flux over the entire surface and defines the effective diffusion coefficient De as: [ ]

Jan 1, 1980

By R. L. Neman

Southern Oklahoma (including the Arbuckle Mountains) has outcrops of rocks representing Precambrian, Paleozoic, and Cretaceous ages. Thus, rocks of every geologic age in the Paleozoic and Mesozoic Eras, except the Jurassic and Triassic Periods, are present in south-central Oklahoma. With rocks of such an enormous age range present in a relatively small geographic area, it is little wonder that a wide variety of economic rock and mineral resources are locally present. This report will describe the occurrence, mining, processing, and end-uses (dictated by chemical and physical properties) of the Precambrian Troy Granite, the Cambrian Royer Dolomite and Fort Sill Limestone, Ordovician silica sands of the Simpson Group, Ordovician limestones of the Viola Springs and Welling Formations, and Ordovician Sylvan Shale. In general, the more the end-use depends upon chemical composition and purity, the greater the price that can be demanded for such-minerals. The not-so-successful attempts to mine zinc, manganese, copper, and iron from the Arbuckle Mountains also will be discussed briefly, and I will provide a sermonette on analytical chemistry and its usefulness to corporate CEOs. I may be one of the few persons at this Forum on the Geology of Industrial Minerals who is not a professional geologist. I am an analytical chemist specializing in geochemistry. In particular, I investigate trace elements in rocks and their consequences in industrial processes. As such, I have consulted to the mining industry (and their clients) for two decades, always with the intent of improving service and product quality.

Jan 1, 1999

By A. C. Lyons

Foreword Sir William Halcrow and Partners are responsible for the design of the Ahmed Hamdi Tunnel as Sub-contractor to the Contractor, Osmac, a joint venture formed by the Arab Contractors, Osman Ahmed Osman and Company of Cairo, and Tarmac International of London. Throughout the paper the term "Client" refers to the Employer, the Ministry of Housing and Reconstruction, which latterly became the Ministry of Development and New Communities of the Arab Republic of Egypt. At the time of writing of this paper only a few hundred metres of the tunnel have been driven, but the design is substantially complete. Introduction The Ahmed Hamdi Tunnel, which is at present under construction, will be a two-lane tunnel crossing beneath the Suez Canal approximately 15 km north of the town of Suez at El Shallufa. It will become the first permanent connection across the Canal since 1967 and is visualised by the Egyptian Government as an early step in the development of the Sinai Desert along the eastern bank. The tunnel will carry pipelines for treated water and electric power cables to assist in this development. The tunnel, which will be 1640 m in length, is being driven through hard clay and mudstone using a tunnel shield fitted with hydraulic excavators. The primary lining is being constructed with precast, bolted reinforced concrete segments with an internal diameter of 10.4 m. The road deck structure and the walls of the air supply ducts beneath it are formed with precast, reinforced concrete units erected immediately behind the shield.

Jan 1, 1979

By D. E. Ranta, Stephen W. Thomas, Clancy J. Wendt

One of the most difficult tasks associated with placer mining is the sampling of the deposit. More placer projects have failed due to inaccurate assessment of the reserves than to any other reason. Within the realm of placers, those containing valuable minerals with a high unit value are more difficult to sample than those with larger bulk, lower unit value minerals. Some items to consider when sampling a placer deposit are as follows: A. A relatively large sample is needed for accurate valuation of the ground being tested. Placers are composed of many sizes of gravel which makes a representative sample difficult to obtain. B. When sampling placers for high unit value minerals such as gold, any error in mineral content of the sample will be magnified in the calculation of reserves. C. Values are usually erratically distributed within the gravel mass. Therefore, some placers with a more uniform value distribution may be adequately assessed with a minimum number of samples whereas a deposit with a highly erratic distribution of values may not be adequately sampled regardless of how many samples are taken. D. The investigation of a placer deposit should be made by, or be under the direction of, a person experienced in the art of placer sampling. F) During a sampling program, items that must be observed and noted in addition to the sample size and valuable mineral content should include boulder size and number, clay content, bedrock conditions, water, frozen ground, false bedrock, and any other physical characteristics that would affect mining of the deposit.

Jan 1, 1992

By James S. Scott

Effluents discharged from gold mills, and more recently from heap leaching operations, pose significant hazards to the environment if not properly managed prior to discharge. This paper describes the nature of wastewaters which must be treated, the treatment processes being applied in Canada and the capabilities of these methods in removing cyanide and metals. As a result of past practice the most common method of reducing cyanide in gold mill effluents remains that of natural degradation in tailings ponds. This method has proven capable of producing high quality effluents where large ponds and sufficiently long water retention times can be provided, but at many mines this has not been the case. Since 1981, as a result of these limitations there has been a strong move in Canada to chemically-based effluent treatment plants, particularly as additional processes became available. Canadian gold mills have become leaders in the use of chemical processes to remove cyanide, in terms of the variety of such processes in operation (five in total), the number of plant installations and the number of processes developed in this country. The hydrogen peroxide and Inco SO2-air processes, in that order, are being applied most widely. Alkaline chlorination, the initial process to be used fairly extensively has been almost totally replaced by the two methods mentioned above. Since a number of effective methods are now available for the treatment of gold mill effluents, the selection of a process for application at a specific mill requires careful consideration of:

Jan 1, 1987

When exploration shows a mineral deposit to be of importance, the subsequent work of defining the limits or boundaries of the ore body and preparing it for the extraction of the mineral is termed development (Young, 1946). In underground mining, development also connotes the work that is involved in opening up a deposit preparatory to stoping or productive operations. In this section, mine development is defined to include all studies and operations that will enable a sound evaluation of an explored ore body from the technical and financial standpoints. Though the ultimate objective of all mine development activities is the same, the scope and detail of these activities vary depending on the type of ore body (e.g., flat bodies, lenses and sheets, massive deposits, narrow veins, and bedded deposits), and the method of working the deposit (e.g., under- ground or surface methods or a combination of both of the methods). Therefore, the various contributions in section 3 address such topics as long-range planning, feasibility studies, and valuation for many types of ore bodies and different mining methods. This introductory review is divided into three major parts. In the first part, long-range planning aspects are briefly discussed with .an emphasis on current trends that affect mine planning. In the second part, an overview is provided of the contents in the mine development and valuation section. In the last part, remarks are made on the status, scope, and future of quantitative and computer methods in mine planning and development.

Jan 1, 1979

By Allan T. Fisk, Carl R. Peterson, Robert G. Lundquist

A long recognized goal in high speed tunneling and mining has been the development of a continuous drill and blast excavation capability. Both the advance rate and the economy of drill and blast tunneling can be significantly improved if the conventional cyclic process can be carried out continuously. Obviously, any continuous drill and blast tunneling machine must be an "all function" device, performing drilling, explosive loading, initiation, mucking, ventilation, roof support (if necessary), and perhaps other functions, essentially simultaneously, while remaining at the face throughout. Furthermore, such a machine must do all these things under remote control. THE SPIRAL BLAST PATTERN Several continuous drill and blast tunneling concepts have been proposed. Of these the Rapidex spiral blast pattern, taking advantage of a partially self-shielding geometry, seems to require the least shielding and hence offers the maximum access for mucking, although from the outset it was clear that remote mucking would present a major design challenge. The Rapidex continuous spiral blast concept uses an unusual blasting pattern that, under the geological conditions tested, has proven to be an effective and efficient means of fragmentation. The concept has a self-shielding characteristic which permits a lightly shielded machine to remain at the face during blasting. The pattern produces a spirally proceeding tunnel face, much like one turn of an auger. The leading portion of the spiral surface is connected to the trailing portion by an axially extending plane surface or bench. The ideal geometry is illustrated in Figure 1 for a horseshoe tunnel section.

Jan 1, 1979

By Ashis Bhattacherjee, Subrata Chatterjee, Michael T. Dewey, Christopher J. Bise

In order to continue the advancements made during the past two decades in the reduction of the severity of accidents and injuries in underground coal mining, closer attention will have to be paid to the increasing number of accidents resulting in disabling injuries and lost time. With the increased emphasis on safety training reflected in the Federal Mine Safety and Health Amendments Act of 1977 (Public Law 96-1641, and on MSHA's current focus on the application of Job Safety Analysis, it appears that the acquisition, evaluation, and application of accident and incident data will take on an even greater importance. To manage this large amount of information will require a significant commitment of time and attention on the part of mine training departments. A USBM-sponsored research project is currently being completed at Penn State which focuser on the development of a model training program for mining. The program is based on five distinct steps which represent the coupling of a needs assessment with the program implementation. The five steps are: 1) database analysis, 2) workplace observations, 3) identification of trainable problem areas, 4) a library of training resources, and 6) the implementation of the program. In each of these areas, the microcomputer has proven to be a valuable tool for collecting, analyzing, and presenting accident and incident information. This paper will detail the manner in which microcomputers have been fully integrated into the model training program. Examples of applications at existing mines will also be discussed.

Jan 1, 1992

By Terry McNulty

There are many potential pitfalls in the commercialization of innovative technology. The failures often are remembered longer than the successes, thereby serving as deterrents to subsequent attempts. The mineral industry's future depends on effective innovation. So it is essential that the causes of failure are understood. Innovation can be examined equally well in the context of geophysics, geology or mining. However the author's experience has been in mineral processing and chemical engineering. So the following discussion is limited to processes and/or plants for producing mineral concentrates, metals or inorganic chemicals. More of what follows has to do with underachievement or failure than success. But this article demonstrates that there is a strong element of predictability in the former. Furthermore, it is a credit to the minerals industry and to the engineering profession that a very high percentage of projects succeed in achieving design capacity and forecast operating costs. Innovation means the introduction of something new. In this article, the words "innovative technology" are used broadly. They include new processes and novel combinations of established unit operations, as well as novel types of processing equipment or largest-ever equipment models. The discussion of project outcomes is based on personal experience or on published information. Citations are given for technical publications that provide either project information or insights into the methodology used to analyze project performance. However, specific projects have not been identified due to the rather negative connotations of some of the conclusions drawn about the less favorable outcomes.

Jan 1, 1998

By Morris Loshinsky, George Ziegler

The New York City Transit System is celebrating its Diamond Jubilee this year. In 1904, 9.3 route miles of New York's first subway was placed in operation in lower Manhattan. Since that date the system has grown to 230 route miles and 458 stations (See Exhibit #1). The age of the system immediately provides a clue to the nature of our construction activity. While we must always plan for the future and expand the system in the direction of the future needs in New York, a substantial amount of time and money must be channeled towards the modernization and maintenance of the existing system which provides vital transportation for 3-1/2 million passengers a day. This paper however will be directed to our New Route's Construction and, specifically, to three rock tunnel and cut and cover sections presently under construction. Currently, New York is engaged in the construction of about 9 New Route miles of structure. Briefly, the 3 Sections we will discuss are as follows: Route 131-A Section 5A is a 4 track structure in Manhattan and includes the new Lexington Avenue Station. This 1240 foot long section is located between Park Avenue and 3rd Avenue and is a combined cut and cover and rock tunnel section under 63rd Street. Route 131-A Section 5B is an intricate 2423 foot long 4 track rock tunnel section extending from 3rd Avenue to the FDR Drive under 63rd Street in Manhattan.

Jan 1, 1979

By M. J. Garcia, Howard Hallman, G. M. T. Marshall, Ken Higby, Louis Cope, Robert S. Hess, John Peters, A. G. Law, William C. Larson

After a good year in 1979-strong mineral demand, adequate prices for most metals, minimal labor problems-1980 was not so good. The US produced $24.8 billion worth of nonfuel minerals last year, up 3.5% from 1979, according to preliminary US Bureau of Mines figures. But the $800 million increase was the smallest annual gain since 1977 and reflected reduced auto and construction industry demand, strikes, and energy shortages. Preliminary figures for 68 minerals show that production of 42 decreased, 25 increased, and one was unchanged. Production of 11 of 21 US-produced minerals was up. Noteworthy mineral events in 1980 included a copper industry strike, increased gold and silver prices, troubles in the iron ore and uranium industries, discussion about a US nonfuels mineral policy, and corporate interest in mining companies as merger targets. Recessionary conditions experienced by the Western world in 1980 resulted in a slowdown in new mine development, evident in the relative scarcity of major new base metal projects. This could lead to short term supply/demand anomalies within the next few years which, in turn, could have a significant effect on metal prices, according to Mining Magazine (Jan. 1981). World Mining (Sept. 1980) noted that US mining strength is in open pit operations. A much lower tonnage is mined underground and is centralized in trona, uranium, lead, zinc, molybdenum, potash and, to a lesser extent, copper. The most notable increase in new underground mines has been in Wyoming's trona district where new mines are being developed and production will increase, the magazine said.

Jan 5, 1981

By Susan T. Bagley, Linda D. Gratz, Kirby J. Baumgard

The extensive use of heavy-duty diesel engines in underground mines has raised concerns about the potential adverse health effects to miners exposed to diesel particulate matter (DPM) which contains mutagenic and carcinogenic organic compounds. The purpose of this study was to compare the levels of DPM, biological activity, and polynuclear aromatic hydrocarbons (PAH) attributable to diesel engines in underground coal mines and similar data collected in engine laboratory facilities to assess whether laboratory data could be used to predict in-mine levels of diesel emissions. Mean in-mine DPM and SOF concentrations varied from 0.90 to 1.9 mg/m3 and 0.08 to 0.40 mg/m3, respectively. DPM-associated mutagenicity (mean) levels at two of the mines varied from 400 to 970 revertants/m3. Concentations of three PAH differed by up to four-fold between two of the mines, largely reflecting differences in DPM and SOF levels. The laboratory raw exhaust data were divided by 100 to obtain expected or predicted values for in-mine concentrations. The predicted DPM, SOF, mutagenicity, and PAH values based on laboratory samples were not significantly different from many of the in-mine values. Using a potential in-mine dilution ratio range of 20 to 200:1, virtually all in-mine data fell within the predicted range. Therefore, an estimate of in-mine concentrations can be determined by evaluating laboratory data. This will allow for extrapolations from laboratory tests with particulate emission control devices to assess potential health-related benefits due to their in-mine use.

Jan 1, 1991

By M. H. Kahn, F. C. Bond, K. J. Edmiston

Comminution of various materials can be achieved in grinding equipment by nipping, impact, attrition, or a combination of these actions. Pna mills also known as edgerunners, chasers, and mullers-are classified as a nipping machine. The essential features of this type of grinding machine are rollers or mullers that turn on a horizontal axis while rating on the bed of material in the pan. Ploughs are used to direct the unground material to the center of the pan. Grinding may be accomplished wet or dry. Aritres, Chilean mills, and Huntington mills are types of pan mills. Ring roll and ring Ml mills, another type of nipping machine, were developed for grinding smaller particles of intermediate hardness to product sizes of about 100 pm. They were designed to attempt to reduce the cost of similar size reduction in ball mills and have been widely used to pulverize coal for power-plant facilities. Impact Machines Grinding machines that can be classified as impact mills include: hammer, cage, centrifugal, vibratory, pin, and stamp mills. The distinctive feature of an impact mill is that it has a fast-moving part that transfers some of its kinetic energy to the material particles by direct contact so that internal stresses are created in the particles. The Reitz Disintegrator is an example of an impact mill. It has rigidly mounted hammers attached to a vertical shaft that rotates in close proximity to horizontally mounted screens. The feed pulp enters parallel to the vertical shaft, and may have a solids content of from 40

Jan 1, 1985

By Frank H. Skelding

A new, large mine is about to be born. Many years and millions of dollars have been invested in exploration. An orebody has been found and proven. All necessary political and legal work to establish rights and conditions for development are complete. The feasibility studies are favorable. Financing has been arranged. Board approval has been given to proceed. The time has come to engage a contractor to design and build the new facilities in a location, as is the common case today, far re¬moved from the centers of advanced technologic development where the minerals will ultimately be used. A select list of Engineering and Construction (E&C) companies is asked to prepare proposals. At this point the common viewpoint among mining companies is that the company's sole remaining problem, a major one to be sure, is to select qualified contractors to design and build the project at the lowest cost and shortest time possible so that production can start generating a return on investment. The purpose of this discussion is to explore the viewpoint of the large E&C contractor toward such projects. It differs in important ways from that of the client mining company and it is these differences and the reasons for them that must be understood by the client if severe difficulties and misunderstandings with the contractor, starting at the beginning of contract negotiation and continuing through design and construction to final startup are to be avoided or minimized. Often enough, the difference is in degree, not kind, which only serves to obscure the fact that a difference exists.

Jan 1, 1975

By Peter G. Sechiari

The Rio Tinto-Zinc Corporation Limited (RTZ), through it exploration company Riofinex, commenced exploration for bauxite in the Amazonia region of Brazil during 1970. Following' encouraging indications, exploration licences were taken out and an exploration programme was initiated In February 1975, a preliminary 'feasibility report indicated that a project, based on the Miltonia plateau located close to the town of Paragominas in the State of Para, was viable and that barging might offer an economic solution to getting the product to an ocean-going port. A, decision was taken in April 1975 to proceed with a full feasibility study. In the latter stages of the study, an engineering consortium of Mendes Junior and Bechtel do Brasil was employed to review, and modify if necessary, the concepts that RTZ had developed for the project's operation. With these concepts agreed, the consortium was requested to make capital and operating cost estimates, and these became available during February 1978. The deposit is being developed by a Brazilian company Mineracao Vera Cruz S.A. (MVC) in which the present share-holding is owned 64 percent by RTZ and 36 percent by Companhia Vale do Rio Doce (CVRD). RTZ is a British based international group of mining and industrial companies with interests in almost every major metal and fuel. CVRD is a Brazilian mining company, 85 percent owned by the Brazilian Government, with a major interest in iron ore and also other non-ferrous metals. It is intended, in due course, that the company will become majority owned by Brazilian interests.

Jan 1, 1979

By P. Somasundaran, S. Venkatachalam, N. K. Khosla, K. Khosla

Froth flotation of alumina particles was studied by employing and hydrogen gas bubbles. The effect of current density was studied over a range of 0.1 to1.6 kA/m2. Compared to hydrogen, the use of oxygen bubbles at any given gas evolution rate resulted in a higher flotation recovery. The existence of an optimum current density, for each given particle size was indicated. Flotation at higher current densities resulted in better flotation kinetics, while flotation at lower current densities resulted in better Spas utilization.

Jan 1, 1996

By Atta Ur Rehman, Kwame Awuah-Offei

This paper examines the effect of bucket geometry (cutting-blade profile, floor profile and blade thickness), speed, motor power output and muckpile particle sizes on bucket penetration and draft for rubber tire loaders. The work uses a 1:16 scale model of a load-haul-dump (LHD) in full-factorial experiments to examine the effect of the variables on penetration and maximum draft. The results show that speed and motor output are positively correlated with penetration and draft, and muckpile particle size is positively correlated with penetration and negatively correlated with draft (p < 0.0014).

By Wen Tao Liu, Tong Tian, Fu Sheng Niu, Xiu Man Liang

The level of automation employed in flotation production is relatively low. In an actual concentrator, operators use their judgment to adjust the production state based on the visual characteristics of the flotation froth surface. There are shortcomings, such as strong subjectivity and lagging process operation, that easily cause the waste of manpower and material resources. Machine vision technology is introduced to replace human visualization, achieving a quantitative description of the visual characteristics of the froth surface. The state variable parameters are provided for the identification of the flotation conditions.