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By George E. Aiken, B. R. Jr. Waples

INTRODUCTION In this paper the author will attempt to bridge from the paper work of design and engineering to the reality of implementation. Certain facets of construction are constant to a successful project, no matter the level of technical complexity. Basic to timely, low cost construction are the people assigned to the project. Construction is not accomplished by robots, computers, or speeches; but rather by people. People do however require the avail- ability of equipment and communications to properly complete the work. ORGANIZATION Good organization is the basic requirement of a well implemented construction project. For this paper the author will suggest an organization chart as well as an activity listing that together support the construction activities. There is little difference in the activities or functions needed to construct a small plant or a large one. It is a matter of how much time an individual has to spend on an activity that determines the structure of an organization. The difference between a large and small plant construction job is often described as the multiple hat versus the single hat philosophy. As an example, a resident construction manager on a small job might be the manager, the field engineer, the scheduler, the estimator, and the procurement manager. At some time during a construction

Jan 1, 1986

By Robert K. Towner, Francis S. Kendorski

Shotcrete drift linings at the Climax Mine of the Climax Molybdenum Company have undergone four years of extensive evaluations as a replacement for thick poured-in-place concrete linings. Any drift lining at Climax must be able to withstand the rigors of undercut and secondary blasting, weight problems induced by panel caving, and the abrasion of slusher mining. Examined here are the conclusions reached so far on shotcrete drift linings which have not yet completed the approximately six-year cycle from development to ore exhaustion. Properly applied shotcrete is an adequate drift lining for all phases of the Climax panel caving system of mining. Undercut blasting will damage shotcrete unless blasts are correctly timed. Weight problems will destroy shotcrete drift linings as efficiently as it will destroy concrete or steel support systems. Abrasion and secondary blasting results are inconclusive as the shotcrete lined slusher drifts have not entered the ore production stage of the mining cycle. In addition to drift linings, Climax has found shotcrete to be invaluable for lining large underground shops, for temporary support systems, for permanent ventilation bulkheads and for the repair of abraded or weight damage concrete lined slusher and haulage drifts.

Jan 1, 1974

By Joginder S. Bhore, Francis M. Keville, David E. Puza, Roger C. Borggaard

A portion of the Massachusetts Bay Transportation Authority's Red Line Extension through Somerville, Massachusetts consists of 1,553cm (5,092 LF) of hard rock tunneling 6.7m (22 ft.) diameter horeshoe, 148m (485 LF) of mixed face tunneling, 7.2m (23 ft.) diameter circular, beneath an active railroad in a heavily commercialized business district. This paper will deal with the excavation of the mixed face area without the use of a shield. It will address the special excavation and support problems encountered during tunneling operations using the floating crown bar and modified spiling methods. Topics covered will include excavation and support methods, cement grouting, compaction grouting, and instrumentation. PROJECT DESCRIPTION The Davis Square to Porter Square Tunnels and Shafts Somerville/ Cambridge, Massachusetts is part of the Massachusetts Bay Transportation Authority's (MBTA) 5.1km (17,000 ft.) Red Line Extension. This extension runs from Harvard Square, Cambridge, to Alewife Brook Parkway, Cambridge through Somerville. This portion (MBTA Contract #091-106) required the excavation and concreting of 1,701m (5,580 LF) of single track twin tunnels consisting of 1,553m (5,092 LF) of conventional hard rock tunneling under 56 residential properties and 148m (485 LF) of mixed face tunneling beneath an active railroad in a heavily commercialized business district. The mined diameter of the mixed face tunnel is 7.16m (23.5 ft.) Access to the tunnel was via the Summer Street vent shaft, and the two Grove Street access shafts where all tunnel excavated materials were removed.

Jan 1, 1981

By D. R. Nagaraj

The chemistry and structure-activity relationships for four new classes of sulfide mineral and precious metals collectors developed recently are discussed in this paper. These collector classes are alkoxycarbonyl alkyl thionocarbamates and thioureas, dialkyl (or diaryl) monothiophosphates and dialkyl monothiophosphinates. The main emphasis will be to highlight the differences between collectors and their affinities for various minerals on the basis of data on kinetics of adsorption on pure minerals, natural ore flotation and microscopy of flotation concentrates. The mechanism of interaction of these collectors with sulfide minerals is also discussed with the available data on the FTIR and solution chemistry studies.

Jan 1, 1989

By Terry Quinlan

The financial evaluation of an orebody uses estimates for the grade of ore produced during each year for the life of the mine. Assay data from the Dolphin Scheelite Mine is used to estimate grades by the Polygonal, Ellipsoidal and Disjunctive Kriging Methods. The results are compared with simulated production data, to show the existence of a bias associated with each method. The affect of bias on the financial evaluation of a theoretical model ia assessed.

Jan 1, 1979

By Frederick W. DeVries

The following charts were presented at the Randol Gold & Silver Forum 2000, held at the Hotel Vancouver (Vancouver, B.C.) from April 18-21, 2000. It must be borne in mind that the "facts" stated and con­clusions drawn by the author were not as the result of a rig­orous technical investigation, but rather as a member of a journalistic team seeking a rapid view for presentation as news to a TV audience. Since the author's visit, some retrenchment on the part of the operators on estimating the cyanide content of the spill seems to have occurred. This does NOT alter the conclusions that (a) the spill was an intolerable embarrassment for the world mining industry, nor (b) the potential damage to future mining investments, should prompt action not be taken: 1. to understand the reasons for the dam failure, and 2. to draw up firm concepts of how to avoid future fail­ures of dams at mining properties containing materials that are toxic, environmentally unfriendly, or with as highly dis­comfiting a profile as cyanide.

Jan 1, 2000

A chartered bus with about 30 attendees of the just completed 1998 SME Annual Meeting headed toward Green Cove Springs, FL, which the author had been told was located somewhere south of Jacksonville, FL. In conjunction with the meeting in Orlando, RGC (USA) Mineral Sands provided a tour of its facility. The author had worked with heavy minerals on a laboratory scale, performing the usual gravity and magnetic separations, but had never been to a heavy mineral mine and processing facility. Years ago as a metallurgist, the author once applied for a job in a heavy mineral operation in Florida -it may have been the same operation. After turning north on to Highway 95, the endless billboards promoting beach-front retirement communities proved the Atlantic ocean was just a few miles away (although the author never caught a glimpse of it). After another hour, the bus suddenly turned west and continued inland for about 65 km (40 miles). The thought occurred, "We are talking about beach sands, what are we doing heading away from the ocean?" As the bus continued inland, the author was struck by the flatness of the land and by the lakes, rivers and wetlands. He was also impressed by the many fine stands of pine and hardwoods. The office of RGC (USA) Mineral Sands is located about 16 km (10 miles) south of Green Cove Springs. Upon leaving the bus, members of the tour were greeted by Graeme Sloan, general manager, and Elliot Mallard, manager of mining. They provided some general information about the operation, including a slide show. RGC's Florida operation produces four concentrates: zircon (ZrSiO,), rutile (TiO,), ilmenite (FeTiO,) and leucoxene (an alteration product of ilmenite containing 67% to 70% TiO,). With a work force of about 170, the annual production of the above products is about 23,27, 45 and 14 kt (25,000 30,000 50,000 and 15,000 st), respectively. RGC also has other mineral sand operations, in addition to gold and base metal mines, mostly in Australia.

Jan 1, 1998

By J. G. Groppo, D. J. Sung, B. K. Parekh

Hyperbaric filtration for the dewatering of fine coal cleaned by froth flotation was evaluated on a laboratory scale. A laboratory pressure filtration procedure designed to obtain a uniform cake structure from dilute slurries containing a significant amount of coarse material is described. Baseline tests were conducted to determine the optimum operating conditions for the eventual application of the process to a continuous pilot-scale hyperbaric filter. Investigated were filter operating parameters such as driving force, time, cake thickness, percent solids, viscosity and pH.

Jan 1, 1996

By Anthony D. Hammond

INTRODUCTION A two-dimensional approach for modeling narrow-vein deposits using the TECHBASE® software was implemented at Sunshine Mining for its use in the evaluation of mineral properties. This 2-D approach prevents the overestimation of high-grade tons typically associated with the use of fixed 3-D blocks and reduces the size of the model in computer memory. The method consists of constructing a two-dimensional model oriented along the average plane of the mineralized structure. This approach works well for single, multiple and intersecting veins with the condition that each vein is roughly planar with variation in dip or strike less than 30" in order to maintain a reasonable resolution in the process of projecting data onto a plane (Figure 1). Also, a precise identification of the hanging-wall and foot-wall location is critical in ensuring an accurate representation of the vein. By using various modeling techniques, the two-dimensional model estimates metal content, thickness, tonnage, economic and dilution parameters which will be ultimately used in the identification of minable reserves. The following is a generic description of the steps involved in modeling a steeply dipping vein. DATA ENTRY A typical project database consists of drillhole coordinates, survey information, assay data and any other quantitative or qualitative data. This database can be created inside the software or imported from any spreadsheet. TECHBASE® utilizes the concept of "fields" and "records" (columns and rows) for storing data. The use of "calculated fields" enables the user to expand on the manipulation of the database with minimum memory requirements. Another important feature of TECHBASE® is the ability to replicate the structure and format of the "tables" for its use in another project and the capability of running a series of repetitive tasks by means of batch and "runlog" files.

Jan 1, 1998

By William T. Griswold

Few metals or industrial minerals can boast a better growth record over the past fifteen years than the borates. This period of growth occurred before the influence of any large-scale use in plastics or high-energy fuels. These new developments not only provide expanding markets, but the programs related to their development are generating research information that will lead to many other new uses. The most dynamic growth areas for refined products of boron or borates are in the acid, the oxide and the reduced forms, such as the metal and the hydrides. Expanding requirements for these products will modify the emphasis on the use of naturally occurring sodium borates. Any borate from which boron can be economically extracted will become a potentially important ore. This is particularly true of the calcium borate, colemanite. Only one large deposit in the Western World has ever been developed where the principal economic minerals are sodium borates, This factor alone would discourage any exploration program directed solely toward the discovery of these ores; on the other hand, ample exploration opportunities for calcium borates exist in the desert regions of California and Nevada. It is therefore reasonable to restrict a program to this region, in spite of geologically favorable areas in foreign countries such as Turkey, Argentina and Chile.

Jan 1, 1959

By Betty L. Gibbs

What does the information age mean to mining companies? The perception of greatly increased access to information is based on modern communications through ‘smart’ fax machines and computer networks. Computer media allow us to `talk' to the President or to a sister in Australia. If we need data to help put together a mining permit, we can find that data somewhere on computer media. The vast amount of easily accessible information quickly overwhelms us. To avoid `information burnout,' we must learn to target searches and be able to discriminate between dross and information that is useful to our goals. If you watch commercial TV, you have learned to screen out most product commercials. A similar screening process must be applied to computerized information sources. You may need to sort through a lot of irrelevant information before finding the pearls you are looking for. ‘Smart’ fax machines can send information with no direct human intervention. MINES FaxBac, for example, from the US Bureau of Mines instructs you to enter four-digit numbers to have particular reports sent directly to your fax machine. Software vendors use a similar system to supply information about their products. You select an item by number, and the related brochure is faxed to your machine. To compete, the industry must maintain access to as many information sources as possible. The availability of computers and software for almost every conceivable application allows us to accomplish work faster than we ever thought possible, even as recently as 10 years ago. Most mining companies have become aware that doing geology, reserves, mine planning and other technical tasks completely by hand is much too slow. The world moves faster, drilling happens faster, mining happens faster, all related activities happen faster. We no longer have the manpower or time to keep all maps. calculations and records up to date.

Jan 1, 1994

By G. S. Brierley, R. D. Drake, J. E. Kelley, J. C. Kellogg

This case study embodies the problems of an underground project under current contracting practices. It will provide a realistic framework for a structured examination of the anatomy of a major complex underground project. Just as it will illustrate the frustrations of the parties to an underground contract, it will also provide a means to examine potential opportunities to provide a better way to develop underground space. Urban Transit Authority (UTA) had planned to expand their heavy rail underground transit system through an extension to an existing line. UTA lacked sufficient funding to guarantee the construction and operation of this planned extension. Venture Partner Associates (VPA) in conjunction with four major department stores entered into an agreement to create a major underground space for a commercial/recreational facility. The concept was to locate the facility adjacent to a planned station and beneath existing aboveground office facilities. This group was known as Commercial Development Corporation (CDC). UTA had reached an agreement with UMTA to provide 20 percent of the line and station costs. UTA then entered into an agreement with CDC to provide the needed additional funding for the station work in return for locating the station adjacent to the planned underground commercial/recreational complex. The agreement called for CDC to contribute 20 percent to the station cost to a maximum of $25 million plus a one percent contribution from commercial/recreational revenues for operating costs.

Jan 1, 1989

By Stephen Hoffman

The Environmental Protection Agency (EPA) is investigating approaches to control non-coal mining wastes. In May 1988, the EPA's Office of Solid Waste (OSW) released a document that outlined an approach to manage non-coal mining wastes and materials. This document was called Strawman I. It was a staff-level approach designed to aid the continued participation of interested parties and to enhance EPA's understanding of mining waste issues. EPA has been working with states, public interest groups and the mining industry to gather information and to solicit input on waste management approaches. The involvement of the states in the Strawman process has been coordinated by the Mine Waste Task Force of the Western Governors' Association and the Interstate Mining Compact Commission. Involvement of public interest groups has been coordinated through Colorado Trout Unlimited. And the participation of the mining industry has been managed principally by the American Mining Congress. In May 1990, EPA released Strawman II. It was based on comments submitted to the EPA on Strawman I and on information given to the EPA by interested parties since 1988. Strawman II is again a staff-level approach to protect human health and the environment from wastes and other materials associated with non-coal mining. In September 1990, meetings were held with public interest groups and the mining industry to discuss their comments on Strawman II. By early 1991, the EPA expects to make a decision on how to proceed with program development.

Jan 1, 1990

By Rossen Halatchev

The production sequence optimization of open pit mine is a procedure that reflects the exploitation conditions over life of mine. These conditions are determined by the geological characteristics of the deposit, requirements of the mining and processing technologies and economic parameters of the exploitation. From a technological point of view the production sequence optimization deals with two aspects - spatial and time. Each of them plays a tremendously important role in searching for the optimum solution of the problem. This paper treats the time aspect of the production sequence optimization. This aspect is revealed in the context of the problem of the working zone formation of the open pit mine in time. The problem formulation places an accent on the determination of the theoretically possible time distribution of the waste and ore quantities of each bench of the open pit mine. A mathematical solution to the problem has been developed based on combinatorial analysis. The solution provides a multi-variant investigation of the production sequencing with the use of an optimization model developed as a linear programming formulation. The model objective function uses the Net Present Value as a criterion for assessing the effectiveness of production sequencing. A case study is provided for the conditions of Assarel copper open pit mine (Bulgaria) to illustrate the applicability of the approach. The results obtained reveal the complex nature of the variation of the Net Present Value as a function of the mining factor.

Jan 1, 2002

By R. P. King, S. Middlemiss

A method is developed to convert a measured distribution of fracture energies to the equivalent work index. The method assumes that the energy required to grind the material from the feed size distribution to the product size distribution is equivalent to the sum of the impact energies that are required to reduce the feed material by successive single impacts to the required product size. The method was tested by measuring the fracture energy distributions for quartz and comparing the resulting calculated value of the work index with the work index for this material measured using the conventional Bond laboratory procedure.

Jan 1, 1998

By Jacek Paraszczak

Numerous problems encountered in the mining of narrow vein deposits challenge the productivity, competitiveness and profitability of many mines. Mechanization of mining operations is one of the most important means to ensure the healthy survival of this mining sector. Vein deposits account for nearly all the world's primary silver production, as well as a significant portion of gold, tin, copper lead and zinc. In North America, narrow vein mining constitutes an important sector of the industry. Operators exploiting such deposits are concerned with the most appropriate mining method and equipment to mine in such a way as to minimize waste rock dilution. Unfortunately, most of the equipment available does not meet the additional geological and economical restrictions typical of narrow vein mining. Thus, mining these deposits is labor intensive and can result in low productivity. Consequently, the profitability of many such mines is reduced. Increased mechanization is one of the solutions to ensure their healthy survival. This paper reviews the state-of-the art in mining equipment with reference to narrow vein mining limitations. Problems encountered Geological conditions and economical factors have a decisive impact on the choice of mining method and equipment. Many ore bodies are relatively small, usually erratically distributed, often less than 2 m (6.5 ft) wide, with dips ranging from 0° to 90°. To make things worse, ore body limits are sometimes difficult to determine and the ground is hard and abrasive.

Jan 1, 1992

By Karl O. Toppel, Jim Flaherty

The desire to minimize gaseous effluent in smelting and maximize gold yields from refractory ore are driving the nonferrous and gold refining industries to demand more and more oxygen. This, coupled with an increasingly competitive marketplace, forces the investigation of alternate methods of oxygen supply. Current progress in both the non-cryogenic and cryogenic fields is making the use of low-purity oxygen much more attractive. The benefits of on-site production are now available to most oxygen users. Historically, these on-site advantages could only be achieved by relatively large plants using high-purity cryogenic technology. The evolution of low-purity cryogenic and non­cryogenic oxygen production has added a new method of delivering on-site production. Specifically, the advent of oxygen Vacuum Swing Adsorption (VSA) technology has brought these benefits to smaller-volume customers by cost-effectively supplying oxygen requirements as low as 20 tons per day, (tpd). Low-purity cryogenic plants have also made an impact on the market, yielding cost reductions for larger-volume customers with oygen requirements greater than 70 tpd. This paper reviews the advantages and disadvantages of current supply methods for users having varying volume, purity and other requirements.

Jan 1, 1993

By Shaning Yu, Yosry A. Attia

The purpose of this work was to investigate the feasibility of using column flotation as a floc separation technique. In this study, the ultrafine coal (minus 25 microns) slurries were cleaned by using the Integration of column flotation with selective flocculation. It was found that using column flotation as a floc separation technique during the "cleaning" stage, achieved much better results than that either using column flotation as a rougher separation technique for coal flocs, or using It directly to recover the ultrafine coal from the slurries without adding selective flocculant. Thus, the ultrafine coal slurries were first separated by selective flocculation process to reject a certain amount of the dispersed ultrafine ash minerals, and to aggregate the ultrafine coal particles as flocs. Thus, the entrainment of ultrafine ash minerals Into the coal floc-froth concentrate during flotation could be considerably reduced. Subsequently, the coal flocs were further "cleaned" by column flotation. The experimental results Indicated that this approach was technically feasible and particularly suitable for a slurry containing a large amount of ultrafine particles. The effect of flotation time, and collector dosage on column flotation of coal flocs were also Investigated and reported In this article.

Jan 1, 1988

By M. Charles Gilbert

Basement rocks in southern Oklahoma are divided into two groups. One group is the Lower Cambrian Wichita Igneous Province, a diverse igneous suite that crops out in the western Arbuckle Mountains and in the Wichita Mountains. These largely bimodal igneous rocks were emplaced in an intracratonic-rift environment. The other group, the older, is a set of Precambrian rocks of the Eastern Arbuckle Province, yielding ages between 1,350 and 1,400 Ma, exposed in the core of the eastern Arbuckle Mountains. These are deeply eroded mesozonal granitic rocks and associated granitic gneisses cut by numerous dikes ranging in composition from diabase to rhyolite. The southern Oklahoma igneous rocks have long been utilized mostly as dimension and crushed stone. Most of the early quarries were in granite of various red hues for monuments and facing stones. Large crushed-stone quarries are now exploiting both granite and rhyolite, which is used chiefly as aggregate and railroad ballast. The exposed basement rocks in Oklahoma represent an underdeveloped and accessible resource.

Jan 1, 1999

By S. R. LaBrooy, M. C. Costello, A. C. Bax

Nickel is present in a number of gold ores in Australia, Africa and the United States. The effects and behaviour of the nickel during the cyanidation and adsorption processes, and also during the elution and electrowinning processes have been examined by a number of researchers, usually as a part of a larger investigation. This paper examines the available data on the behaviour and effect of nickel during cyanidation and its associated unit processes. The presence of nickel is often not considered to be particu­larly important as it does not cause the same degree of problems across the circuit as those experienced in the presence of copper. It can however lead to increased cyanide consumption during leaching, and reduced adsorption of gold onto carbon. A proportion of nickel cyanide may be removed from carbon prior to elution by carrying out a hot (90° C) acid wash. The nickel which remains on the carbon will be partially eluted during the main elution step, and, dependent on its concentration in the pregnant solution, part of it may be deposited during electrowinning. There is always a risk that any nickel remaining on the carbon after the elution step will be reduced to metallic nickel during the regeneration step. This may ultimately result in an increasing base level of nickel on the carbon, as metallic nickel is insoluble in both cyanide and hydrochloric acid.

Jan 1, 1995