Search Documents

By Mahmood B. Mirza

The geology of the Gulf Coast Salt domes has been extensively studied by Kupfer (1,2,3,4,5), Atwater (6,7), Balk (81, Hawkins (9), and Wharton (10). dominant geological feature of Southern Louisiana is the Gulf Coast Geosyncline. The axis of this geosyncline corresponds with the present day coastline of Texas, Louisiana, Mississippi, Alabama and Florida. This geosyncline has been continually subsiding since Cretaceous times and receiving large deltaic accumulations of sediments from Central North America. These accumulations progressively thicken toward the South. In the vicinity of the Coast, these sediments are reported to be about 40,000 feet thick. Another dominant feature of the region is the large number of salt domes scattered along the Gulf Coast (fig. 1). Typically, these domes are roughly cylindrical in shape, 1 to 5 miles in diameter, and extend to more than 20,000 feet in depth. It is hypothesized that these domes are derived from the thick Louann salt formation lying below the deltaic sediments. Due to its low specific gravity and buoyancy, the salt layer protruded upwards plastically and pierced the overlying strata. As a result of this upward flow, the adjacent strata are locally lifted upwards, creating excellent traps for petroleum accumulation.

Jan 1, 1979

By Brian T. Hamilton, Richard Piliounis, Cian Murphy

"The Eglinton-Crosstown Light Rail Transit line is a 19-kilometre corridor with a 10-kilometre underground portion currently being constructed by Metrolinx in Toronto through a densely populated urban environment. Tunneling works are being completed through two separate design-bid-build contracts that include consideration for a phased handover to a follow on contractor who will take ownership of the tunnels, including warranties, and will complete the stations and remainder of the system through a PPP delivery model including maintenance of the system for 30 years. Warranty provisions, settlement apportionment, tunnel leakage, potential delays and conflicts between contractors are just some of the risks the team managing tunnel contract integration had to consider when developing the PPP contract. This paper will present an overview of how these risks were assessed and allocated through the contracts and the strategies adopted to minimize risks to Metrolinx while ensuring successful procurement was maintained. INTRODUCTION The Big Move is a 25 year, $50 billion ($-CAD) plan for coordinated and integrated transportation in the Greater Toronto and Hamilton Area (GTHA) in Ontario, Canada. This plan has been initiated by Metrolinx, a division of the provincial government of Ontario, and its vision, goals and objectives are rooted in creating a high quality of life; a thriving, sustainable and protected environment; and a strong, prosperous and competitive economy for the GTHA. The Big Move will triple the length of rapid transit service in the GTHA to 1,725km, significantly increase the percentage of the GTHA population living within two kilometers of rapid transit, reduce commute times to an average of 77 minutes per person per day and decrease greenhouse gas emissions from passenger transportation per person by 29%. Work is currently underway on several projects and more than $16 billion ($-CAD) of the planned investment has already been committed. A key project that forms part of this commitment is the Eglinton Crosstown Light Rail Transit (LRT) Project which is being delivered in the City of Toronto under Metrolinx’s Rapid Transit (RT) Program. This complex and sizeable undertaking has been broken into a number of separate contracts comprising: LRT Vehicles contract; Eglinton West Tunnels Project; Eglinton East Tunnels Project; and a Public-Private-Partnership (PPP) contract to complete the underground stations, at-grade stops, all rail infrastructure and systems and to maintain the entire system for 30 years. The PPP contract, which includes an initial capital portion of approx. $5.1 billion ($-CAD), has recently been awarded to Crosslinx Transit Solutions, a Special Purpose Vehicle (SPV) consortium comprised of SNC Lavalin, Aecon, Dragados and EllisDon."

Jan 1, 2016

By Scott G. Britton

This chapter discusses the necessary construction techniques for installing coal mine ventilation devices. Included in the discussion are the major air controlling devices called over- casts, regulators, stoppings, and doors. Under-casts, although a valid device, are used infrequently in coal mining and are not discussed here. Typically, coal mines require a great many ventilation devices to control the air movement. Post-I969 mines have had to design their air systems to comply with the Federal Coal Mine Health and Safety Act (CMHSA) as discussed in Chap. 1. Pre- 1969 mines have had to redesign major portions of their systems to comply with the basic components of the law such as separation of air courses, single unit split ventilation, and minimum air quantities. It is not uncommon, therefore, to find a large mine (2.0 Mt/a) requiring several hundred overcast installations (permanent, as well as repeat construction), plus doors and regulators placed among a thousand or more stoppings. When each of these devices is subject to leakage from installation and weathering defects, the importance of effective construction becomes evident. An historic rule of thumb for average mine ventilation says that about 70% of all the air pressure generated by the mine fan is lost between the portal and the working faces. Of course, this rule is subject to many factors, but the message is clear: there is a tremendous inefficiency in controlling leakage through common air devices. This chapter strives to present a standard approach and design alternatives which can go a long way in reducing this leakage, and hence, ventilation costs. Historically, mine ventilation has progressed from natural, or draft ventilation, to fire-induced ventilation (Fig. l), furnace-fired centrifugal fans and finally, to today's modem mine fans. Underground controlling devices have been in use in the coal mines since the late 1600s, but the CMHSA of 1969 was the real turning point for mine ventilation. Minimum quantities and velocities of fresh air were required for mining, forcing coal operators and engineers to reevaluate and improve their systems. As a consequence, the cost for ventilating air increased. Today, companies face a variety of choices among design alternatives, materials, labor, and costs of ventilating devices for their mines. The best approach for any individual company or mine is determined by (1) the needs of the mine, and (2) the local design parameters. In my discussions of ventilation construction I shall be fairly general in terms of device installation steps, where specifics are warranted for clarification, I will include this information.

Jan 1, 1983

By James E. Gingrich

The new Track Etch* technique for uranium exploration has been utilized in several survey programs conducted during the last few years. The results from these programs have been very encouraging, and new uranium ore bodies have been discovered by using this new technique. The Track Etch method is being used in several exploration programs in various locations around the world. The Track Etch exploration technique utilizes small pieces of special radiation-sensitive plastic film to detect the presence of radon gas which is released by uranium ore bodies. Because of the selectivity and sensitivity of the technique, ore bodies not normally detected with other surface or airborne monitoring methods are found. Since no large equipment or special training of personnel is needed, the Track Etch technique is easily used in field operations. The basis for the Track Etch method, its application in field exploration programs, and the results obtained to date in locating uranium ore bodies is discussed.

Jan 1, 1974

By Lawrence Adler

The properties of a geologic mass may be considered from a resource or an engineering viewpoint. The primary engineering applications include ground control, excavation, bulk handling, and hydrology. This study will focus upon these areas in descending order. For an adequate geologic description, data is necessary on the following components: (1) the intact rock, (2) geologic structures, (3) contained fluids, and (4) existing pressures and temperatures, see Table 1. This information, combined with the engineering specifications, provides the basis for a formal geotechnical analysis as illustrated in Figure 1. For a structural analysis it is essential to establish the mechanical properties of the material composing the structure. This material, termed the "rock mass," consists mainly of the first two geologic components, the intact rock and geologic structures (Figure 1) Consideration of fluids will be subordinated to their role as chemical agents affecting the mechanical properties. The existence of pressures and temperatures generally lies beyond the scope of this study.

Jan 1, 1973

By Roland B. Drugge

The adaptation of pelletizing processes involves the coordination of various factors such as temperatures, gas flows, productions, etc., in order to obtain optimum performance. The consequent problems are considerable due to the large number involved as well as the lack of knowledge of their correlation. It is therefore essential to establish a fundamental theory which takes into account the heat transfer phenomena and the secondary factors which are relevant to the properties of the product. Straight grate and grate kiln pelletizing processes involve heating of a stationary bed on a travelling grate. The heat transfer conditions are therefore of primary importance. This is why this article pays particular attention to conditions which obtain when a stationary bed is heated, in which certain special reactions occur. The conclusions drawn from this penetration of the heat transfer phenomena can be expressed in postulates acting as guide-lines for the establishment of proto-typal processes. Examples of elaborating such processes are also given in the article. Some operational experience at LKAB are also given.

Jan 1, 1975

By M. J. DeJong, R. J. Mair, S. Ritter, G. Giardina

"For urban tunneling projects it is essential to predict and prevent building damage. Although various case studies and experiments have shown that buildings considerably modify greenfield soil movements, widely accepted damage assessment methods neglect this soil-structure interaction and simplify structures as linear elastic beams. This paper summarizes an experimental investigation of the response of more realistic structures to tunneling-induced deformations. Small scale structural models with façade openings and brittle material properties were 3D printed and tested in a geotechnical centrifuge. Soil and structure displacement data were obtained by image-based measurement. Results demonstrate that structures notably mitigate differential greenfield ground displacements. It is also shown that maximum soil settlements, horizontal soil displacements beneath the structure and structural damage in the form of cracking significantly depend on the position of the structure in the settlement profile. The results provide a basis from which to predict building settlement response with greater certainty. INTRODUCTION With continuing population growth and increasing urbanization expected in the next decades, there is an urgent need for a next generation of infrastructure. It is likely that a large part of this infrastructure will be underground. Such creation of urban underground space frequently involves the excavation of shallow tunnels in close proximity to existing structures and utilities. For example, along the Crossrail project in London more than 1,200 structures are located within a possible influence area of the tunnel construction (Torp-Petersen and Black 2001). The assessment of building damage plays a vital role throughout the planning, design and construction stage of urban tunneling projects. However, while predictions of tunneling-induced deformations in the greenfield can generally be made with some confidence, much uncertainty exists about how structures interact with ground movements arising from tunnel construction."

Jan 1, 2016

By J. L. Yordan

An induction time apparatus has been constructed in the present work which has a sensitivity limit of 100-150 micro-seconds. The basic unit is similar to the one used by Eigeles and Volova (1960) and Trahar (1983), but it operates with a micro-computer and has a greater sensitivity. Using this apparatus, the flotation chemistry of the quartz-amine system has been studied. It has been found that at a given dodecylamminium hydrochloride concentration, the induction time is at a minimum at approximately pH 10.5. At this pH, the collector hydrolizes to form neutral amine and the flotation recovery reaches a maximumy,suggesting that iono-molecular species are the surface-active species responsible for flotation. This finding confirms the earlier conclusions obtained using the surface tension (Somasundaran, 1976; Finch and Smith, 1973) and contact angle (Smith, 1963) techniques. The induction time measurements have also been conducted as a function of particle size, collector concentration, indifferent electrolyte concentration and temperature. The results are compared with flotation data, and the activation energies for the bubble-particle adhesion have been calculated.

Jan 1, 1986

By A. Khan

The effect of sulfur dioxide on collectorless and collector induced flotation of chalcopyrite was studied by cyclic voltammetry on a rotating disc electrode. Contact angle measurements were made to determine the effect of sulfur dioxide concentration and electrochemical treatment. The benefits of sulfur dioxide in enhancing the selectivity of separating chalcopyrite from complex sulfide ores are discussed.

Jan 1, 1996

By William H. Mount

INTRODUCTION The requirements of mine ventilation demand the constant attention of the mine operator. Just as the physical mine structure changes with time, the ventilation requirements of a particular mine change considerably from season to season and even from day to day. No ventilation system can remain adequate indefinitely; and all systems require monitoring and adjustments to achieve proper ventilation. Instead of being given fore- thought and planning, mine-ventilation systems too of- ten are erected hastily, merely to correct an already un- healthy situation. The usual result is an inefficient and costly system that, in some instances, may prove in- effective in providing fresh air to the point of need. The ventilation of mines is a combination of both art and science. The fluid that must be moved is in- visible; its properties change drastically with temperature, barometric pressure, and humidity; and the methods of measurement are not precise. In part, ventilation engineering must rely upon the art of good industrial ventilation experience and sometimes even the trial-and- error method. However, the properties of air can be determined with relatively inexpensive equipment; with some care, measurement accuracies within 5% of the actual values can be obtained. Thus the art of ventilation gradually is being supplanted by improved engineering practices. Although the direction of flow and the volume may not be predicted correctly by airflow equations in every situation, it is better to try to predict the behavior of a given ventilation before installation than to proceed blindly with a system design. When used with the discretion that comes from education and experience, the basic laws of ventilation can provide sub-stantial insight into the design of an air-handling system; and they can prevent wasteful or even dangerous designs from being installed. Since the mine operators who read this text will have varying amounts of exposure to ventilation theory, the basic laws of airflow and of mechanical ventilation are presented in the first section. The emphasis has been placed on the interpretation and use of fan characteristic curves that are supplied by fan manufacturers. Considerable information can be obtained from these fan curves, particularly when they are used with a graphic model of the mine, drift, or duct in which the fan or fans are to be installed. A few minutes spent comparing the various characteristic curves can help the designer obtain the correct fan for the job. However, the under- standing of a few fundamentals is necessary; and this text has been prepared to provide ample and understandable information in a "how-to" style. In subsequent sections of this text, more down-to- earth subjects will be covered, including the problems of air recirculation, relative merits of installing fans in series or in parallel, expected maintenance requirements (vibration, lubrication intervals, etc.), fan noise and some remedies, effect of an inlet bell on the fan per- formance, basic air-measurement techniques and equipment, and similar miscellaneous items. Although this text is not intended to be a comprehensive bible of mine ventilation, it has been prepared as a guide that provides some useful information to individuals responsible for the quality of the underground environment. Every person working underground is en- titled to the safest environment that can be provided within the limitations of existing technology and at a reasonable cost. Adequate ventilation is well within both limits, provided that the system is designed intelligently, in conjunction with the mining plan, and not as an after-

Jan 1, 1982

By A. D. Wunderlich

Providing a safe & secure environment for your employees and other company assets is absolutely necessary in our litigeous society. Security hardware is no different than computers or other technical equipment, in that new equipment is developed each year that makes older equipment obsolete. This presentation will help to explain how your existing security system and security procedures can be updated to meet industry standards without the expenditure of a great deal of money. If you are concerned about potential security problems and how to address these problems, this presentation is a must.

Jan 1, 1995

By Brian Mangogna, Clay McNail, Weishi Mang, Adam Steimel

Together with innovatively applying modern flotation reagents and developing the breakthrough mill enterprise expert control and operating system, Doe Run Buick Mill constructed an advanced large copper rougher scavenger to process its complex Pb\Zn\Cu ore more efficiently. The scavenger circuit, featuring its own motor control center, air blower, multiple reagent loops and FrothSense+™ camera, operates both mechanically and chemically to maximize copper recovery and under expert control. Such scavenger features can be applied to zinc rougher circuits for all Doe Run mills to maximize Cu recovery during Cu special runs when the zinc rougher becomes a copper rougher scavenger.

Feb 1, 2025

By Clement K. Chase, J. A. Eisele, Paul D. Chamberlain, Terry Laverty, Lee Rice, Larry Sevenker, Albert G. Law, Daryl Tweeton, John Peters

"Name your poison," wrote Forbes, Jan. 3, 1983, in an article describing the plight of much of the mineral industry as it entered the new year. "To ask which (mining) segment is better these days is almost like asking which of several stones would make a better life preserver." "The scene has seldom seemed darker or apparently less promising," said the Mining Journal in June 1982. And the Northern Miner described the year as the third in a "3-year drought which has completely dried up (company) coffers." Thus, 1982 became the worst year for much of the mining industry since the Great Depression. Low prices, commodity surpluses, output reductions, layoffs, temporary and permanent closures, and financial losses made headlines as the general recession continued to hurl blows at an industry facing strong foreign competition, increased government regulations, and plummeting market demand. At fault were tight US monetary policies and the resulting high interest rates that, while forcing inflation to slow, also threw the economic wheels of the country into reverse gear. Automobile production, housing starts, consumer durable sales, and capital spending all fell dramatically. US industrial production fell about 8.5% in 1982, with the GNP dropping by 1.7%. Production Value Not a single mineral escaped this recession. According to the US Bureau of Mines, US nonfuel production value dropped for all but four out of 21 metals and 14 out of 44 nonmetals. Production quantities increased for only gold, lead, and zirconium among metals and for only six nonmetals. Total nonfuel mineral production value dropped a whopping 21% from 1981 levels, the largest decline since 1938 and the first since 1971. Production value was estimated at $20 billion. Metal commodities showed heavier losses than nonmetals-37% vs. 12%-because of their link to depressed automobile and construction industries. Prices From peaks in early 1980, prices of precious and base metals, ferrous and nonferrous metals, and virtually every mineral dropped to 30-month lows in June 1982. Gold dropped to $9.64/g ($300/oz) compared to a high of $27/g ($850/ oz). Silver was quoted below 164/g ($5/oz) versus a $1.61/g ($50/oz) high. Copper was offered at a five-year low of $1.22/kg (55.5¢/lb) compared with a high of $3.30/kg ($1.50/lb). Lead went for 53¢/kg (24¢/lb) versus $1.21 (554). Nickel begged for buyers at $4.19/kg ($1.90/lb) compared to a high price of $7.72/kg ($3.50/lb). Molybdenum was available at or below $8.82/kg ($4/lb), down from a high of $44/kg ($20/lb). Cobalt went for $11/kg ($5/lb) versus $55/kg ($25/lb). Adjusted for inflation, increased currency costs, and currency devaluation, many of these prices are the lowest reached in decades. Financial Profits & Losses Low prices severely impacted companies' earnings, turning profits into sometimes disastrous or fatal losses. Robert Norton, director of the US Bureau of Mines, noting there has been a recession in the mineral industry for years, said, "Profit rates as related to invested capital have been considerably lower (for mining) than those of other industries. Mineral industry profits have been subject to greater cyclical swings and debt equity ratios have been significantly greater than

Jan 5, 1983

By Donald E. Ralston, William B. Seward, Washington Bernard, William J. Halvorsen, Richard P. Killmeyer, Kelvin K. Wu, Peter Phillips, John N. Murphy, W. H. Mullins

Despite a recession that's crippling many US industries, and a UMW strike that wasn't supposed to happen, 1981 was a fairly good year for the coal industry. The big news was record-high exports. Queues of colliers waited for weeks at Hampton Roads, VA, and Baltimore, MD, to load coal destined for Europe and the Far East. Private industry and city governments began scrambling for a share of the export boom, and port developments were planned in nearly every coastal state. Coal exports jumped from about 82 Mt (90 million st) in 1980 to a record 83 Mt (92 million st) in 1981, according to the National Coal Association. NCA projects exports to remain at this level 1982. The following statistics illustrate industry performance in other areas: • Demand by domestic utilities and overseas customers was so strong that total US consumption reached 760 Mt (838 million st) in 1981. DOE predicts another record year in 1982, with consumption forecast at 804 Mt (886 million st). • 1981 production of 730 Mt (805 million st) was just slightly below the record high of 748 Mt (824 million st) in 1980, "a remarkable figure considering that UMW production was shut off for 72 days during 1981," says NCA President Carl Bagge. Production in 1982 should set a new record, 800 Mt (880 million st). • Eastern coal production fell 7.4%, while western production-largely unaffected by the UMW strike-rose almost 10%. NCA says eastern output will rise almost 12% to 538 Mt (593 million st) in 1982, and western production will increase by 6.6% to 266 Mt (293 million st). • Production per manhour is improving. After the strike, weekly production hit the 16 Mt (18 million st) mark and has approached the 18 Mt (20 million st) per week level. •Coal's share of the US electric generation market increased from 51% in 1980 to 53% in 1981. Electric utilities are coal's biggest customer, and their financial situation is precarious. Inflation has thwarted necessary expansion plans, while shifting environmental regulations have played havoc with construction costs. Utilities increased power sales by only 2.5% in 1981; NCA predicts that utility coal use will increase 4% in 1982. The Association's long-range forecast indicates that growth in electricity demand in the immediate future will be much lower than in the 1960s and 70s. Administration Impact Industry optimism following the election of Ronald Reagan and a Republican-dominated Senate didn't survive the year. One bright spot was the appointment of James Watt as Interior Secretary, and his promises to review surface mining regulations and resume leasing. The administration, however, has declined to support federal eminent domain for slurry pipelines and expects port users to foot most of the bill for expansions and improvements. It has also drastically reduced government financial support for synthetic fuels. The outlook for synfuels-one of three major markets for coal-has

Jan 5, 1982

By D. Murray

"The Mine Improvement and New Emergency Response (MINER) Act included the need for improved chemical technologies to address respiratory protective device inadequacies and refuge alternative development. The National Institute for Occupational Safety and Health’s (NIOSH) National Personal Protective Technology Laboratory (NPPTL) invests in research and development to improve the carbon dioxide (CO2) scrubbing technologies built into these mine safety systems. Testing at NIOSH NPPTL is performed using a custom-designed test system containing a chemical reactor and sensors in a constant flow of simulated expired breath to evaluate chemical performance for the scrubber materials. Current testing procedures focus on device duration or capacity, but do not report criteria needed to effectively optimize chemical performance. In this presentation, testing results which identify the chemical performance roles for CO2 scrubber components will be reported, and specific component chemical activities will be linked to both duration and CO2 absorption capacities. Chemical components being evaluated include hydroxyl, superoxides, metal, and amine active sites, distributed in salts, zeolites, metal-organic frameworks, and microporous materials. INTRODUCTION CO2 absorbents and oxygen sources are at the heart of closed circuit breathing air supply systems used in mining escape and rescue operations. CO2 absorbent technology was first developed for diving rebreathers and has been in use for over a century. Typically these devices include a soda lime formulation of pellets in the 8-12 mesh range. Larger 4-8 mesh particles are used in medical grade “low-flow” applications, since these particles present a lower flow resistance regime more amenable for use with resting individuals. Potassium superoxide and lithium hydroxide formulations are also used, where in each case the formulations involve bulk solid pellets or materials affixed to surfaces. CO2 capture technologies are now under intensive study in the energy and automotive industries, where the pursuit of optimal combustion processes has led to the development of new materials to capture, convert and store CO2, oxygen and carbon monoxide gases. Recent advances in nano-structured and high surface area catalysis have produced novel materials demonstrating chemical performance improvements in these industries, and these improvements may now also be adapted to enhance chemical efficiency and performance in escape and rescue devices. Higher surface area materials offer promise for improving the efficiency, or decreasing the burdens associated with the use of closed circuit respiratory protective devices containing CO2 absorbents. Novel chemicals that display advantages in chemical performance or decreased burden will be examined for inclusion in developing systems such as the next-generation closed-circuit mining escape respirator or refuge alternatives."

Jan 1, 2018

By Homer S. Anderson

To clarify what r mean about this long title, I would like to define the term technology. A standard definition of the word "technology" is "a technical method of achieving a practical purpose". Incidently, another definition of the term is merely "technical language". The same dictionary defines the word "technology" as "having a special, usually practical, knowledge of mechanical or scientific subject." Naturally, the practical purpose of the subject with which we are concerned is solving of problems we encounter in the mining industry. I might further describe the subject of this discourse by defining the term "manager". An old definition, "one who dispenses the duties of his position with care and economy." In line with the above definition most of the technology with which we in the mining industry are confronted with deals with some form of cost reduction. This may be related to the speed of doing an operation or to saving of labor or supply costs. These can be improvements of an existing method or the result of new processes or inventions, such as new machinery.

Jan 1, 1974

By James R. Taylor

24.1-BASIC PRINCIPLES JAMES R. TAYLOR The basic principle involved in maintenance is protection of a company's investment through the care and upkeep of machinery and equipment, buildings and properties. Maintenance is justified through making available to the maximum extent possible the facilities, machines and services required by the operating and production departments in their function of insuring optimum return on investment. As the size, cost and complexity of the equipment used in modern mining and related industries increase, operating and production personnel become proportionately more dependent upon maintenance engineering for its contribution to the overall profit picture. A greater part of the total cost now is charged to maintenance and the maintenance group becomes a major company unit. Basic maintenance concepts have changed very little over the years, but the advances in methods and technique have brought about tremendous challenge and have in consequence assumed a greater influence and importance. The older "sledge- hammer" methods have given way to engineered and scientific systems, while the accelerating development of intricate equipment and machinery, and the instrumentation essential for control, demand an ever-increasing upgrading of maintenance personnel. Regardless of this growth in importance, cost and complexity of the maintenance function, it is important to remember that it is not an independent and self-sufficient unit, but is a necessary facet of the entire plant operation and is subject to the company's total production effort. As one part of a team, maintenance is successful only when functioning cooperatively wit11 the other departments it serves Close collaboration in all areas served by n maintenance group is essential if it is to function fully to protect the company's investment, whether the assets are in machinery, materials or people. 24.1.1-MAINTENANCE SCOPE Maintenance functions may be grouped into the two general classifications of primary and secondary. This grouping constitutes a basic division although, in practice, the scope of the maintenance activity varies in each mine or plant and is subject to differences in size and type of operations and company policy, plus the influence of precedent, which may be sectional or industry-wide. The primary functions supply the justification for the maintenance engineering department. while secondary functions are variable according to plant conditions and needs. The primary functions may be categorized as follows: 1. Maintenance of existing machinery and equipment. 2. Maintenance of existing buildings and grounds. 3. Inspection and lubrication of equipment and machinery. 4. Utilities generation and distribution. 5. Alterations to existing equipment and facilities. 6. Installation of new equipment and facilities. 7. Instrumentation.

Jan 1, 1973

By Sheldon P. Wimpfen

Forecasting, an ancient art, is con-ducted by everyone in varying degrees. It is a vital aspect of mineral production and conditions must be predicted over a long time frame in all aspects of the industry from exploration to plant construction. Although many government agencies as well as private industry make forecasts, there are insufficent "make good" analyses performed. The performance of more such studies could sharpen forecasting ability.

Jan 1, 1983

By David M. Kjos

Large diameter autogenous and semi-autogenous grinding mills represent the primary thrust of the expanding grinding technology. In spite of initial difficulties, large autogenous and semi-autogenous mills have reached an acceptable level of technology which provides the mineral engineer with a reliable, low cost means of ore comminution. A successful milling installation begins during the design stage of the grinding mill and the plant it is to be installed in. This is particularly true in autogenous and semi-autogenous mills. Critical mill and plant design factors should be considered while the mill and installation are still only ?paper.? Various current liner designs will be discussed ranging from lifter bar/plate to integral types. Modes of operation such as "high-low" will be considered. Liner maintenance procedures ranging from laydown area in plant design, proper mill shutdown methods, to installation and bolt tightening complete the equation to yield optimum performance possible for any particular grinding application. The objective of this paper is to discuss trends in wear materials, designs and operating practices, and provide some guidelines for good practice as we move through the 1980's. We will put together concepts that relate to the designs, materials and applications so that higher performance can be obtained by the operator for his specific application. The concepts are shown as being in series because they are dependent on each other to achieve the desired performance.

Jan 1, 1985

By Josef Martinsen

This paper describes two-lane dual motorway tunnels under construction in Bergen. The tunnels are part of a by-pass motorway system throuth the most congested area of the city of Bergen. The tunnels are unique due to their length, heavy traffic, longitudinal ventilation system and the use of a tunnel boring machine, or "TBM", to excavate through hard rock. The tunnels are being built by The Norwegian Public Road Administration and the TBM was delivered by the Robbins Company. The diameter of the TBM is 7.8 m and the tunnel profile is cut by conventional drill and blasting methods in the tunnel's lower half to attain a two lane motorway tunnel. This paper also describes proposed fjord crossings along the Norwegian west coast where the TBM may be used due to its great advantages in comparison to conventional drill and blasting methods.

Jan 1, 1987