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By Anthony Harding

In a world of technology and electronic communication, it is easy to forget what engineers do best with a problem: sitting around a table, exchanging views and ideas with sketches and respecting everyone?s view. This was the approach adopted in the project to arrive at a solution for the cross passage opening sup-port for the Seattle University Link Extension. Schedule and space constraints usually impede concurrent cross passage excavation and tunnel boring machine (TBM) operation. And where the space is constrained, opening support solutions that maximize available cross sections are of great benefit. While there are a number of solutions that minimize space, some of these solutions can require expensive steelwork and extensive drilling and fixing. However, following a detailed round-the-table discussion of the options and constraints, it was identified that a shotcrete shell would not only limit obstruction of the space during installation, but also permit easy installation, particularly around services, and avoid costly steelwork and drilling and fixing.

By Madan M. Singh

This section is unique to the Handbook in that it is the only section that deals with underground excavations for nonmining purposes. The editors were of the opinion that the section should be incorporated because the subject matter covered by the chapters is closely related to mining, and many mining engineers are currently involved in these activities. As we enter the decade of the 1990s activities in this category will increase, enhancing the relevance and utility of the material discussed. As the population increases, especially in metropolitan areas, the necessity to go underground will be greater. At the present time, not only are subsurface shopping malls and pedways connecting buildings becoming commonplace, but structures as diverse as the Civil and Mining Engineering Building on the University of Minnesota campus, a road-and-fleet maintenance facility in Multnomah County, OR, and even an ice cream parlor (Dairy Queen) in northern Wisconsin have been constructed underground. Placing utilities below the surface has numerous advantages and is now customary. Rapid transit and highways through tunnels in urban areas have been the norm for many years, but subterranean stormwater reservoirs, power plants, industrial warehouses, and food storage silos are relatively new innovations. The philosophy of underground defense installations is ancient, but their requirements and designs have trans-formed radically as technology advances. The use of under-ground space for disposition of wastes is modern, since it is recently that environmental concerns and waste disposal costs have assumed increased significance.

Jan 1, 2008

By R. Benito

The publication of the Lerchs Grossmann paper in 1965 outlining a threedimensional graph algorithm for ultimate pit definition set the standard for the mining industry regarding pit optimization. Although the algorithm provides a solution from a static standpoint (i.e., assumes instantaneous mining), it is widely used for commercial packages to generate ultimate pit limits and intermediate phases. However, the solutions delivered are presented in canned reports lacking connection to the original data, which prevents further data analysis and extended reporting. The approach presented in this paper attempts to overcome such barriers by performing openpit optimization through databases. An adaptation of the Lerchs Grossmann graph algorithm is used to generate nodes, arcs and tree structures in customized tables to determine the maximum closure of a graph.

Nov 1, 2013

By Matthew Deutsch

A common casualty of modern openpit mine optimization is the assurance that the resulting design is actually achievable. Optimized mine plans that consider value and a bare minimum of precedence constraints do not, in general, translate into practical, operational mine designs that can be used in the field. Ultimate pits may come to a sharp point at the bottom. Schedules may require taking small parcels of material from many disparate areas of the pit in a single period, and grade control polygons may be ragged, narrow and not minable with realistic equipment. In this paper, these three fundamental openpit mine optimization problems are addressed by encoding them as maximum satisfiability problems. Maximum satisfiability provides a useful framework for problems that are nonlinear and may guarantee the optimality that metaheuristics cannot.

By Ralph P. Hackl

Ore at the Congress gold property, located near Goldbridge, British Columbia, is extremely refractory with most of the gold disseminated in fine-grained arsenopyrite. Metallurgical testwork conducted by Giant Bay Biotech Inc. indicated that biooxidation pretreatment was capable of increasing cyanide gold recovery from the ore to greater than 90%. To determine if the bioleach process could be successfully scaled up, a 225m' (7950-cu ft) commercial size bioleach reactor was built and tested at the mine site in 1989. At that time, the tank was the largest bioleach reactor ever operated. The objectives of the program were: • to ascertain if the biooxidation rates obtained in lab and pilot-scale reactors could be duplicated in a commercial scale tank; • to identify agitation conditions under which the process will function optimally; and • to demonstrate the bioleach process on a scale sufficient to satisfy the owners and potential investors.

Jan 1, 1990

By T. M. Storer

Much has been written and many discussions held on the virtues (and evils?) of a Company-owned motor fleet. Almost invariably these dialogues take a generalized form and thereby lose something since the individual circumstances, geography and philosophy - particularly in diverse industries, is never quite the same. In considering the nature of my remarks today, I felt a departure from the general approach might be in order, and in lieu of that, will attempt to present a concise picture of how we in the Lehigh Portland Cement Company view this problem and the steps we have taken in our efforts to solve it. At the outset a word may be in order about the Lehigh Company itself, what we do, and the problems that confront us specifically as well as the cement industry at large. We are primarily a manufacturer of portland cement operating 10 plants with a total annual capacity of about 23,000,000 barrels. We market this material in 30 states, shipping both from the plants directly as well as through a system of 18 distribution terminals. About 150,000 truckloads of cement are shipped to customers each year.

Jan 1, 1969

By A. S. Speirs

Over the last few years, the never-ending search for mineral wealth has taken the exploration efforts of Canadian mining companies further and further into the High Arctic and isolated locations where regularly scheduled transportation and communication facilities are nonexistent. Names such as Black Angel, Nanisivik, Asbestos Hill, New Quebec Raglan, Rabbit Lake, and Arvik are today frequently mentioned in mining publications. Twenty years ago, mining in these locations was unheard of, mainly due to logistic problems. However, improvements in the design and use of helicopters, STOL aircraft, and icebreakers in northern areas have helped to overcome these problems, making these locations more attractive to mining companies. Since 1969, when Redpath completed its first Arctic project at Texas Gulf's Scrathcona Sound property on the northern tip of Baffin Island, Redpath has been actively involved in contracting and engineering projects in three general areas: the High Arctic, Ungava and Greenland. A map showing some of these projects is shown in Figure 1. In these areas, permafrost conditions exist from a depth of 274 metres in Ungava to a depth of approximately 610 metres in the Little Cornwallis Island area, with rock temperatures ranging from -5°C to -13°C. Outside temperatures range from a low of -50°C in the winter to a high of 21°C in the summer. High winds in the winter result in wind chill factors lower than -73°C

Jan 1, 1980

By Michael Li, Kathryn Rogers, Arie Moerman, Mike Cooper

The Brunswick Mine, a Division of Noranda Inc., produces zinc, lead, copper, and bulk lead-zinc concentrates through underground mining of a large massive sulphide deposit. The mining method employed is longhole open stoping with delayed backfilling. In 1996 Brunswick began a review of its mining methods and backfilling operations. In 1997 the decision was made to convert the backfill system from cemented and uncemented rockfill to paste backfill prepared from mill tailings. This paper will describe the features of the backfill preparation and distribution systems, review the handling of technical issues, and discuss experiences since plant commissioning.

Jan 1, 2001

By Samuel A. Rasmussen

Lead anodes are used in commercial copper electrowinning operations, yet there is no method to calculate anode life. To be discussed in this paper are operating characteristics of rolled plate (Pb,Sn,Ca) alloy anodes at Morenci's electrowinning tankhouse along with fundamental operating conditions and how the anode reacts to these conditions. These include anode maintenance, electrolyte temperature and viscosity, cobalt concentration, and manganese concentration. Also to be discussed are anode substrate characteristics under normal operating conditions and how the corrosion rate is affected by changes in operating conditions.

Jan 1, 1995

By Richard B. Jacob

The High Gradient Magnetic Separator (HGMS), also known as the High Gradient Magnetic Filter (HGMF), is an effective device utilized in magnetic separation. This method of separation is gaining popularity in the separation of sub-micron material containing feebly magnetics. The most common use of this type of separator is in the removal of iron stained particles to improve the brightness of kaolin clay. Potential areas for use of this magnet include: (1) desulfurization of coal (2) the clean-up of mill effluent (3) removal of fine particulate matter from municipal and industrial waste (4) desulfurization of oil

Jan 1, 1983

By Thomas J. Kingston

A general overview of the taconite crushing process at Minntac is presented The process is controlled from a central control where the control room operator uses closed circuit TV, computer process control and alarms, graphic panels, and radio communication to roving attendants to run the Plant. This paper points out the operating controls and parameters as the plant operator sees and uses them.

Jan 1, 1980

By Richard V. Good, John B. Harvey, Lloyd S. Jones

INTRODUCTION The term "Rapid Underground Excavation" is generally associated with high speed tunnel advance with large volumes of excavation, and indeed this is the type of work for which most of the recent innovations in methods and new machinery have been developed. However, the term applies as well to any underground excavation process that results in an earlier project completion than would be expected with conventional methods, and hopefully with a decrease in total unit excavation cost. Often significant progress has been made during the primary stages of an underground construction project and then an inordinate amount of time and effort has been expended on small units of "miscellaneous" excavation which has delayed the overall project completion and escallated overall unit costs. Construction at the Nevada Test Site of the Atomic Energy Commission for underground testing frequently requires significant amounts of so called "miscellaneous mining" such as short access drifts, cross cuts, alcoves, niches and concrete keyways. Many of the keyways must be excavated without disturbing the rock beyond the excavation lines and construction scheduling often dictates that much of the work must be accomplished without disturbing sensitive electronic equipment already installed. In order to cut down on lengthy and costly delays required for the tedious manual excavation of much of this miscellaneous mining, a market search was made for suitable mechanical excavation equip-

Jan 1, 1997

By R. R. Odman

The Malmberget Division of LKAB is located 70 km north of the arctic circle and has about 2000 employees. The dominating products are sinter feed concentrate and pellets. A general flow sheet for the operation is shown in Figure 1. About 20 percent of the ore body consists of hematite, which is mined separately and processed into sinter feed concentrate. That pert of the ore consisting of magnetite passes through a dry cobbing plant. The robbing process includes crushing, screening and dry magnetic separation. The entire cobbing product is used as feed for the wet concentrator. After rod mill grinding and magnetic separation the concentrated slurry is classified. The coarse fraction (+200 mesh) becomes sinter feed concentrate and the slime fraction after further ball mill grinding and magnetic separation, becomes pelletizing feed. A small quantity of the magnetite ore is processed into special iron-rich products in the the wet concentrator. Two types of pelletizing plant are used, shaft furnace and straight grate. This paper will deal only with experience gained at the straight grate plant.

Jan 1, 1979

By Harold L. Lovell

The areas of application, the limitations imposed by water chemistry as well as the advantages and disadvantages in the use of limestone for the treatment of coal mine drainage have recently been described by the authors (1),(2), (3). The process has been demonstrated in continuous, full-scale operation to yield a treated water meeting specifications established by the Pennsylvania Sanitary Water Board and containing excess alkalinity. Their final pH levels are usually less than seven, a condition which avoids consumption of excess neutralization reagents, but which occurs with lime-based processes and results from unwanted side reactions. Operating experience has been cited by Calhoun (4) using ferric waters while others (5), (6), (7), (8), (11), have reported on related research efforts. Despite the advantages including ?the relative simplicity, and minimal costs of the process, there have been very limited industrial applications of mine drainage neutralization with limestone. Although any treatment of these waters may be considered as a temporary control measure (9), the lack of feasible, immediate alternatives, the extensive magnitude. of the waters and the high cost of treatment requires that optimum processes should be utilized and that operating experience in their use be developed as is feasible. This paper will review treatment experience with a ferrous water of moderate pollution loading .

Jan 1, 1972

By F. B. Brost

In 1976, a decision was made by Anamax Mining Company to install an unusual conveying system to transport ore 10.3 km (6.4 mi) from the new Eisenhower Mine to the Twin Buttes concentrator. The system, supplied by Cable Belt Limited of the United Kingdom, represents a radical departure from conventional belt conveyors. The driving tension is applied through two endless wire ropes driven by a single 2 240 kw (3 000 HP) drive while the belt acts only as the ore carrying medium. Full production was begun in January, 1979. Start-up problems hampered production for several months but were resolved by a joint Anamax-Cable Belt effort. The system has been operating at design capacity for 4-1/2 years, and has proven itself as a reliable, low cost ore transportation system.

Jan 1, 1984

By C. F. Kaiser

The Broken Hill proprietary company Limited grate kiln pellet plant (1) located at Whyalla in South Australia commenced production on May 13, 1968. During commissioning, about 25,000 long tons of fluxed pellets were produced. Plant performance was satisfactory and acceptable under the plant guarantee. For production reasons, it was necessary to curtail the fluxed pellet run and revert to the production of acid pellets. In 1970, some 250,000 long tons of fluxed pellets were produced under varying operating conditions to determine the requirements for optimum quality pellets at acceptable production rates. In excess of 180,000 long tons of these fluxed pellets were exported to Japan. Problems experienced in production of the fluxed pellets are detailed, and the quality of the fluxed pellets compared to that of normal acid pellets produced at Whyalla. Brief Plant Details Run of mine ore treated was predominantly soft and friable and contained an average of 66 per cent Fe, 1.7 per cent Si02 and 1.8 per cent Al203. The main iron mineral in the ore was hematite with some martite also present. Plant feed was ground dry in ball mills 11 ft in diameter by 29 ft long to a Blaine surface area of 1600 sq.cm/g and the ground ore was wetted in a pug mill. Balling was carried out in balling drums 10 ft in diameter by 32 ft long. Induration equipment included an eighteen windbox grate 12 ft 2 in. wide by 164 ft 1 in. long, a rotary kiln 18 ft 6 in. diameter by 118 ft 8 in. long and an annular cooler 50 ft mean diameter by 7 it wide.

Jan 1, 1972

By John W. Stevenson

At the No. 4 Mine of Jim Walter Resources in Tuscaloosa County in the North Central part of the State of Alabama, the Mary Lee and Blue Creek coal beds lay 2000 feet below the surface. The quantity of methane gas stored within the coal bed reservoir at this depth and released during development mining necessitates that each coal producing section be ventilated using large air quantities approaching 100,000 cfm. In order to meet coal contractural commitments in the early stages of mine development by installing the necessary number of continuous mining machine units and to develop the mine to projected air shaft sites, high pressure, large volume mine ventilating fans were required. This presentation discusses the installation start-up and changeover procedures when two size GAF 31.5-28-1 TLT-Babcock 3500 Horsepower fans with adjustable pitch in flight blades were put on line while phasing out two Jeffrey Mining Machine Company 8HUA 117 Fans. A graph will be presented to depict the most economic diameter shaft size under 2000 feet of cover with different air quantity requirements.

Jan 1, 1982

By Pierre J. Wauters, Eddy J. Jacques

Starting up a fan or modifying its setting point either by rotational speed variations or blade angle changes, obviously results in new ventilation conditions in the network, which is, of course, the object of the operation. However, since transient phenomena may then occur, particularly in complex networks, there may be a need to simulate these situations prior to any action. This is all the more true, if we are dealing with a multiple interactive fan sys- tem. Simulations with a transient model have shown that the flow in certain airways could be temporarily reversed due to the pres- sure variations that reach both its ends with a different time lag. This phenomenon may cause dangerous situations to occur in cases of fire or outburst of methane. It is also true that the air flow could be reversed in secondary and less powerful fans, while still rotating in the normal direction. The study and the experimental investigation of the extension of the reverse flow characteristic is therefore justified from two points of view : • a numerical simulation model for transient flow conditions must be capable of handling temporary reversed flows, and thus have appropriate fan characteristic curves available over the entire operating domain; • while operating fans, reversed flows should be avoided or at least reduced. Therefore, the design of start-up procedures or real time control algorithms should take these phenomena into account. A particular interesting application is the operating of two fans in parallel. In order to investigate experimentally the characteristic curves of a fan under reversed flow conditions a small scale model was built. This facility was designed in such a manner that it was possible to carry out experiments concerning flow reversions and to try out sequential start-up procedures for two fans in parallel.

Jan 1, 1997

By Michael E. Lively

DOUG HALBE: We've talked about copper operations and gold operations. For our third section on the topic "Operating Ideas That Have Saved Me Some Bucks," we'll turn to the coal fields. Our featured speaker is, I'm almost embarrassed to say, a mining engineer, Mike Lively. Mike has 25 years' experience in the coal industry. He is currently superintendent of surface operations for Southern Ohio Coal Company, Meigs Division (AEP Company). I've read his paper, and there's some really great information here. Mike.

Jan 1, 1998

By John Marsden

JIM ARNOLD: Our next speaker is John Marsden. John runs the concentrator complex at La Candelaria Project in Chile. John's a Royal School of Mines graduate and he wrote the book on gold metallurgy, The Chemistry of Gold Extraction, which, by the way, he dedicated to me-at least that's what my copy says. [laughter] John, go ahead. (Message shown on Projection screen) ‘Raulerson’s Rules Plant operators and maintenance personnel should be asked to participate early in the design process. This ensures that the plant will never be completed on time or within budget.’ JOHN MARSDEN: Good afternoon, everybody. My presentation this afternoon is going to be very short. It won't be as funny as Joe Keane's, but I guarantee you it will be a lot quicker. [laughter] That transparency isn't mine, actually. [laughter] You're trying to throw me off.

Jan 1, 1998