Search Documents

By Raymond W. Peterson

The practice of Countertrade and all of its variations has increased dramatically during the last five years in great part due to the worsening world economic situation and the Third World's increasing debt problems. Conventional wisdom has held that the goods finding their way into countertrade will tend to be manufactured goods of ever increasing value added. It is my contention that this has not been the case. The continued depression of most metals and minerals prices has conspired to keep a great number of metals and raw materials in the forefront of countertrade negotiations. The concept that if a country needs hard currency it will simply sell metals into world markets for cash has been significantly modified by countertrade which encourages subsidies for raw materials which are in turn funded by higher prices for the manufactured goods which the country must import. Countertrade is a term that is relatively new to most of us who have been involved in the international trade of metals and minerals, but it is one that we will continue to hear more of in the future. Countertrade as it is generally known today had its beginnings after the Second World War in Eastern Europe. As the shattered economies of Europe struggled to right themselves, a "cashless" system of trade developed. This system included such ancient concepts as barter as well as more modern ones like bilateral clearing agreements. For over 30 years countertrade was confined mainly to the COMECON nations and their various trade protocols with Third World nations. If metals and minerals were involved, there was little disruption of world markets by such examples as Cuba shipping ferronickel and sugar cane to the U.S.S.R. for a host of manufactured goods and oil. As the world's economy began to slow in the late 70's and the debt crisis began in earnest in the early 801s, this all began to change. As more and more nations which had previously been almost totally dependent upon their mineral wealth over-extended themselves in an attempt to industralize, they concurrently found their income from minerals falling, due to the decreased demand and subsequently lower prices available in the marketplace. At first these nations attempted to balance their payments by promoting the sales of their high value-added manufactured goods. We have all heard numerous examples of U.S. companies going to sell their high technology products in Rumania or Yugoslavia and being confronted with counterpurchase requirements for machine tools, shoes or drill bits. When faced with these demands, a number of companies chose not to sell into those markets while others merrily signed up the obligations without much intent to carry them out. The Performance Bonds required were generally minimal, especially when considered in light of the high margin inherent in high tech items; and the penalty clauses were equally small or nonexistent. A third group of companies actually tried to buy the machine tools or drill bits either for their own internal use or resale but found that due to poor quality and high prices, they were faced with a difficult if not impossible task. This is not to say that no one was able to fulfill a countertrade requirement, but the success ratio on these transactions was incredibly low. This was one of the major contributing factors to the reputation that countertrade has gained as a discipline ... "that it is mostly talk and very little action." As this situation slowly evolved, both the countries imposing the countertrade obligation and the exporters assuming the obligation began to realize that something

Jan 1, 1986

By Peter Joralemon

Introduction The Sierra Nevada Foothill Gold Belt in California extends from Mariposa north for more than 420 km (200 miles). It includes the Grass Valley and Alleghany districts in the zone of Northern Mines and the famous Mother Lode to the south. The gold belt has produced more than 3.1 kt (100 million oz) of gold since its discovery in 1848. This remarkable production, at the present gold price, would be valued at more than $40 billion. The Law of Gambler's Ruin supposes that averages are based on systematic rather than random variations. It emphasizes the vast differences between finite and infinite probability. By applying this Law to this figure, it can be seen that the belt has produced an average of 15.5 t (500,000 oz) of gold per running mile. Many geologists believe, with some justification, that less than half the gold in this belt has been mined. Sixty per cent of the past production has come from lode deposits, the balance from Tertiary and Recent placer gravels. This paper will concern itself with the developing lode mines along the Sierra Nevada Foothill Gold Belt. As a further and final note regarding placer mining along this belt, Mark Twain suggested that placer miners, having lost their senses, had contributed liberally to the population of California's insane asylums. After a 40-year lull with little or no gold production, the lode mines of this famous belt are showing signs of renewed activity. Two open pit mines, the Sonora (Jamestown) and Carson Hill, are now in operation at substantial scales. Two others, the Goldenbell (Pine Tree-Josephine) and the Royal-Mountain King, are being readied for production on equally impressive scales. All are in the southern part of the Mother Lode. Exploration farther north, at Sutter Creek, Drytown, and Georgetown, is showing encouraging results in developing deeper lode deposits. This new activity has been sponsored to a large extent by junior Canadian mining and exploration companies. Most of the established American mining companies have looked the other way, not participating in this important development. One major reason for domestic disinterest in this opportunity is there is little chance for heap leachable open pit ore in this belt, excluding Carson Hill. And heap leaching has become fashionable with American mining companies today. Also, this great old gold belt must have been worked out, for why else is there so little activity here - Catch 22 logic. Another reason is that if a new deposit of size and grade similar to the mines in the past was found, high costs would preclude a profitable operation. And, finally, California environmentalists would not permit mining, even if a rich deposit were found. These may all be pefectly valid reasons not to explore for gold along this belt. But a look at the history of gold mining in California may suggest that the future for exploration and development of the gold resources in the Sierra Nevada Foothills can be greater than the past. It was during the Depression of the 1930s that this gold belt saw its maximum activity, with more than 3000 mines in operation. Some were father and son operations producing only a few tons of ore a day. Other mines employed hundreds of miners to hoist more than 900 t/d (1000 stpd). Some ores were of marginal grade. Others, like the Sixteen to

Jan 7, 1987

By Robert L. Sundeen, Richard V. Wenberg

Service vehicles, often called support vehicles or auxiliary vehicles, are used in secondary functions to support production activities such as loading, drilling, and timbering. Probably the most common support vehicles are the personnel carriers used to move miners to and from work areas. Utility designs are used to transport supplies and various less mobile equipment. Specific application designs are used for special work such as explosives transportation and loading, equipment maintenance, and equipment lubrication. PERSONNEL CARRIERS Personnel carriers are available in a wide variety of sizes and configurations. Some are two-wheel drive, though most are four-wheel drive. Smaller versions carry at least two men and usually have sufficient capacity to carry a small payload of supplies or equip¬ment. The American Motor's 05 Jeep, equipped with an optional diesel engine, has been adapted successfully for this light duty. Larger personnel carriers with ca¬pacities of 12 to 20 or more men currently are available, as shown in Fig. 1. The designs often are customized to the operating characteristics of each mine. All meet the latest federal requirements for rollover protection, emergency brake systems, etc. UTILITY VEHICLES Utility vehicles are adaptable to numerous duties. Probably the most common are ordinary haulers with a flat bed or low-sided box. They are used for hauling supplies and equipment from one point to another. Some occasionally are used for towing and may pull one or more trailers. Fig. 2 shows a typical utility truck. SPECIAL-APPLICATION VEHICLES Special-application vehicles are possibly the most important of all support types since these vehicles di¬rectly support and maintain production equipment. Such vehicles are available in a wide variety of sizes, mechanical functions, and operating specifications. Most versions are four-wheel drive and articulated. Among the more common vehicles are explosive haulers and loaders, mechanic's trucks, lubrication trucks (Fig. 3), and special carriers. TYPICAL APPLICATIONS Development Utility haulers are essential in trackless operations to bring supplies to advancing headings. Some utility haulers may be dedicated to bringing in steel sets and may be equipped with boom lifts to unload heavy sup¬ports or even place them as required. A rockbolt hauler may have a boom-mounted operator's basket which can be used for bolt installation or inspection. Various mechanic's trucks and pipe trucks service the heading to keep power, air, water, and ventilation at the face and to keep face equipment at maximum utilization. Production Production operations require a variety of support equipment. Because of the larger crew size brought about by the addition of the production force, personnel carriers play a greater role. Correspondingly, steel¬support hauling equipment and bolting trucks usually see limited application. PRODUCTION UNITS Capacity Personnel carriers are available to carry almost any number of people desired. Likewise, other types of carriers or haulers can and are built to fit specific re¬quirements. Physical size, capacity, and operating char¬acteristics can be varied to fit any size of opening and operating condition. Generally, articulated models offer greater maneuverability than straight frame-axle steer designs. Most vehicles of this type are lower in power than production units, generally under 74.6 kW (100 hp). Operating performance still compares favorably to that of production equipment, i.e., the support vehicles can travel at equivalent speeds on the various mine gradients. Manpower Auxiliary vehicles should require only a single opera¬tor. Specific application vehicles may require more than one person. For example, ventilation trucks usually require a crew of two where pipe must be installed.

Jan 1, 1982

By Nellie E. Guernsey, Louis J. Sousa, Alfred Weiss, Nickolas J. Themelis

Over the past decade, numerous factors have led US copper firms to face increasingly severe competition from low cost foreign producers. As a result, greater attention is being devoted to developing and implementing new technology that can reduce costs and maintain the competitive position of domestic firms while simultaneously meeting environmental requirements. To obtain a better understanding of the likelihood of the development, adoption, and use of innovative copper technologies in the future, the Bureau of Mines contracted with Mineral Systems Inc. of Stamford, CT, to undertake a systematic survey of technological experts in industry, government, and the academic community. According to the survey, major developments in exploration over the next 25 years are likely to be in technologies that facilitate analysis and interpretation of deposit data rather than those that enable the collection of additional data. Most new copper mining and beneficiation technologies are likely to represent evolutionary extensions of existing systems with a notable increase expected in the application of information systems technologies and computer control methods. A possible movement towards increased usage of continuous mining systems in copper was also noted. Experts indicated that several copper smelters are under consideration for extensive renovation and, as a result, flash smelting technology is expected to become much more widely used in the US. A gradual movement toward continuous smelting methods was also forecast. In copper refining, the major technological change expected is the gradual automation of various refinery operations. Finally, though increased usage is expected, in situ solution mining and hydrometallurgical processing of sulfide ores are not expected to become widespread over the forecast time horizon. This first article in a two-part series describes the survey method chosen and the technological innovations selected for eval¬uation. Also discussed are the assessment panels, background scenarios, critical events, and diffusion forecasts. Next month, part two will address technology forecasts resulting from the study. Featured are discussions on future copper exploration, mining, beneficiation, smelting, refining, and recycling. A cost/benefit analysis will also be included. Methodology Selection of Assessment Method To develop a consensus forecast of technological change in the copper industry, a technique for systematically polling subjective opinions of experts was required. After conducting a literature survey and some preliminary testing, the direct probability assessment method was selected. With this assessment method experts are asked to express in quantitative terms their judgment of the probability that a specified event will occur, usually over a series of time frames. The method was chosen because the experts were observed to be more comfortable with this approach during the testing period, and the results of this process effectively satisfied the assessment objective. The experts generally could provide more precise estimates of the timing of future events using this technique because it was the least cumbersome of the assessment methods tested. Identification, Selection, and Description of the Technologies The initial list (Table 1) of innovative copper technologies assessed in the study was developed from two principal sources: knowledge and expertise of the study team and a review of relevant technical literature. From this list of 47 potential technologies, 10 were selected for detailed assessment. Table 2 lists 35 technologies that were subsequently identified in the first series of assessments. Twelve technologies from this list were also selected for detailed evaluation in a second assessment round. Criteria used for the final selection of technologies for detailed assessment specified that: • The expected impact of each technology on copper supply (i.e.,

Jan 9, 1983

By K. J. Reid, I. Iwasaki, T. Sabelin

Introduction Occurrences of platinum group minerals (PGM) in mafic and ultramafic rocks in association with Cu-Ni mineralization are well known. Yet for the Duluth Complex, a large body of dominantly mafic igneous rocks in northeastern Minnesota with significant Cu-Ni mineralization (Bonnichsen, 1972; Boucher, 1975; Watowich, 1978; Weiblen and Morey, 1980), little has been published concerning its platinum group element (PGE) contents and mineralogy. In a previous study of massive sulfide rock, sperrylite (PtAs2) was found in nickel arsenide and recovery of arsenide minerals by flotation has been investigated (Iwasaki et al., 1986; Ryan and Weiblen, 1984). Recently, an announcement was made of the discovery of significant quantities of platinum and palladium [peak assay values of 9 g/t (0.27 oz per st)] in an interval of a drill core with disseminated sulfide mineralization 16 km (10 miles) southeast of Ely, MN (Anon, 1985; Sabelin, 1985). This paper describes PGM from the Pt-Pd-enriched zone and evaluates their potential for concentration. Geologic setting The Pt-Pd zone occurs in the South Kawishiwi in¬trusion near its basal contact at 734 to 737 m (2408 to 2418 ft) depth. The South Kawishiwi is one of several minor mafic intrusions that constitute the western margin of the Duluth Complex near Ely, MN (Fig. 1). It is com¬prised of a 70.1- to 350.5-m (230- to 1150-ft) thick sul¬fide-bearing basal unit of troctolite with minor amounts of anorthosite, norite, picrite, and oxide layers overlain by a troctolite unit with interlayered anorthosite (Bonnichsen et al., 1980; Foose, 1984; and Foose and Weiblen, 1986). The basal unit, in which the Pt-Pd zone is found, is markedly heterogeneous in rock type, lacking any coherent internal stratigraphy, and shows evidence of both pre- and post-consolidation faulting (Foose and Weiblen, 1986). Geochemistry Chemical analyses were made on 0.3-m (1-ft) intervals of crushed drill core material (1/4 core, BX size) at 731.5 to 740.7 m (2400 to 2430 ft) depth and the results are presented in Fig. 2. The analytical techniques used were atomic absorption spectrometry for silver, chromium, copper, and nickel; a coulometric titration method for sulfur; and a combined fire assay-DC plasma technique for gold, palladium, and platinum. Figure 2 shows the significant enrichment of platinum and palladium at 734 to 737 m (2408 to 2418 ft) depth; it corresponds to a stratigraphic interval rich in oxide minerals. Average values for platinum and palladium contents over the 3-m (10-ft) interval are 2520 and 2580 ppb, respectively, or 5.1 g/t (0.15 oz per st) platinum plus palladium. Platinum plus palladium contents from individual 0.3-m (1-ft) intervals are as high as 9120 ppb or 9.1 g/t (0.27 oz per st) and average 7.4 g/t (0.22 oz per st) in a 1.5-m (5-ft) interval in the richest part of the zone. The Pt-to-Pd ratio is nearly 1:1 over the entire 9.1-m (30-ft) interval and the platinum and palladium correlate closely with chromium, which ranges from 1.9% to 5.3%. Copper, nickel, and sulfur contents for the drill core interval are also given in Fig. 2. In¬terestingly, the Pt-Pd high corresponds to a depletion in copper, nickel, and sulfur. Mineralogy of the Pt-Pd zone The Pt-Pd zone occurs within an oxide-rich zone or layer that consists essentially of oxide minerals, plagioclase, and olivine. The oxides may constitute as

Jan 1, 1987

The Sandvik Group (Sandvik AB), headquartered in Sandviken, Sweden, continues to expand its worldwide operations growth. After recent acquisitions, including Tamrock, headquartered in Tampere, Finland, the company now has annual sales of more than US$5 billion (SEK 40 billion). With the acquisition of Tamrock, Sandvik has further increased its interests in the mining industry. Sandvik Rock Tools, a familiar name in the mining industry, is one of the world's leading suppliers of rock-drilling tools. And Tamrock is one of the world's leading suppliers of drilling machinery, loaders and equipment for rock-excavation operations. Sandvik believes that the two companies combined offer customers "maximum productivity through total system solutions, including machinery, service and tools." In 1997, Tamrock posted sales of US$940 million (SEK 7.5 billion). In addition to its expertise in drilling tools and equipment, Sandvik is supported by its collective resources in specialty steel and cemented carbide. These resources include extensive research and development capabilities, with annual investments in R&D now at about US$150 million. As a result of the R&D programs, internal expansion and acquisitions, the company has nearly doubled in size during the past four years. From 1994 to 1997, nearly US$1 billion was invested in internal growth and another US$825 million has gone towards acquisitions. Return on net assets is now 22% annually. In addition to Tamrock, acquisitions of interest to the mining community include Drillmaster Inc., Houston, TX. The acquisition of Drillmaster (by Sandvik Rock Tools) has further strengthened Sandvik's position in down-the-hole drilling tools. Other major recent acquisitions by Sandvik include Kanthal, a Swedish manu¬facturer of metal and ceramic-resistant materials for electric heating furnaces, household appliances and elec¬tronics, and Precision Twist Drill, Crystal Lake, IL, one of the leading producers of high-speed cutting tools. With more than 38,000 employees worldwide, the Sandvik Group is divided into six separate business areas. Each area is responsible for its own R&D, production and sales: ? Sandvik Mining and Construction. Including Tamrock and Sandvik Rock Tools, this business area boasts of offering the most comprehensive range of "rock-working" products. These include drilling rigs, loaders, rock-excavation equipment and rock drilling tools. ? Sandvik Specialty Steel. This area includes Sandvik Steel and Kanthal, manufacturers of stainless steel tube, strip wire and bar, as well as high-alloy steel and specialty metals. ? Sandvik Tooling. This business area consists of tools and tooling for metalworking applications. Sandvik Coromant is a market leader in the development, manufacture and marketing of tools using cemented carbide, ceramics and extremely hard materials, such as diamond and cubic nitrite. CTT Tools is the world's largest manufacturer of high-speed steel tools and is now expanding operations into solid cemented-carbide tools. ? Sandvik Hard Materials. This segment produces a full range of "hard materials," ranging from cemented carbide to diamond. This area manufactures and markets a full range of cemented carbide blanks for tool manufacturers, as well as components and rolls. ? Sandvik Saws and Tools. This business area manufactures high-quality handsaws and metal saw blades, as well as hand tools ranging from wrenches to chains for logging machines. ? Sandvik Process Systems. This segment manufactures steel belts, process systems and automatic sorting systems for the chemical

Jan 1, 1998

By V. Anthony Cammarota

MINERALS INFORMATION PROGRAM Mineral data collection by the Federal Government actually began in 1882 with an appropriation by Congress to the U.S. Geological Survey (USGS). Although the Bureau of Mines was instituted in 1910, it was not until 1924 that the collection, interpretation, and dissemination of worldwide information on production, consumption, and availability of minerals became the responsibility of the Bureau. The objective of the Bureau's minerals information program is to maintain and provide reliable, timely, and comprehensive data for analysis of national minerals problems. This program is implemented by a staff of specialists who cover about 100 mineral commodities and the mineral industries of 168 countries. Data are also provided on the minerals industry on the State and county level. The specialists analyze information to identify trends and problems, forecast future U.S. and world supply and demand for the nonfuel minerals, and relate trends and developments to their impact on the domestic minerals industry. Data Sources and Publications The primary sources of data concerning the domestic minerals industry are the companies that produce, use, and trade in these minerals. Approximately 60,000 survey forms are sent to industry, on a monthly, quarterly, semiannual, or annual basis, to obtain the data. Domestic trade data are provided by the Bureau of the Census, U.S. Department of Commerce. Information on mineral developments abroad is developed by Bureau specialists from mineral reports supplied by U.S. embassies worldwide, from primary source documents, from a review of the technical mining literature, and from onsite mine and plant visits in foreign countries. The information is disseminated through a number of Bureau publications: "Mineral Industry Surveys" provide aggregated data on a monthly. quarterly, or semiannual basis to give timely information on the most important mineral commodities. "Mineral Commodity Summaries," published each January, provides preliminary annual data on supply and demand and discusses significant events of the previous year. The final data are published later in the "Minerals Yearbook," which is the definitive historical record for mineral statistics. "Mineral Facts and Problems," an encyclopedic work issued every 5 years, covers industry structure, technology, supply-demand analysis. economic factors, reserves, and forecasts of U.S. and world demand for individual commodities. "Mineral Perspectives" and "Mineral Issues" cover important international mineral developments and significant issues of current U.S. policy as they relate to minerals. Discussions and analyses of mineral trends and developments also appear in other Bureau publications, such as "Minerals and Materials" and "Information Circulars." These publications provide the basis for analysis and policy determinations by the Bureau and by virtually every Federal agency concerned with minerals, defense issues, the national economy, and foreign relations. The data are also used by industry in planning capital investments in mines and processing plants, by financial analysts, by U.S. delegations in their work with international commodity groups, and by a host of other minerals related organizations. Data Bases The data bases used by the specialists for preparing publications or in response to a continuous stream of inquiries include both those that contain individual commodity data from respondents, and those that are summary data bases on production, trade, capacity, employment and a number of other minerals-related items, not all of which are derived from data reported to the Bureau of Mines. The data bases maintained on the mainframes are not accessible by non- Bureau users. A 10-year data base of supply- demand data, published each year as an update of tables that appear for each commodity in Mineral Facts and Problems, is available on a floppy

Jan 1, 1987

By Spencer R. Titley

The subject of this lecture, a late century perspective on porphyry copper geology, is one of current interest and importance as the search for these ores remains intense. It is presented in the belief that an appreciation of our present understanding of the subject requires it to be viewed historically, thus providing a basis for evaluating appropriate directions for con¬tinued study. At the outset, it is important to note that the technology of mining and extractive metallurgy has developed ore from these low grade orebodies, starting with D. C. Jackling, and has continued to create them as copper grade and price have diminished. But the continued search for them is a geological problem that responds to growing expectations of people and societies; exploration based upon ever increasing knowledge of the habits of the ores has been very successful. This is the story of evolution of geological thought and practice in porphyry ore search across an interval of time beginning with the bulk mining of "low grade copper ores at Bingham and ending with late Century concepts. "How did we get here?" The lecture concerns the ideas of many different people. The ideas and events discussed reflect a bias on North American thought, where the great low grade orebodies were first recognized as such and where many of the basic geological ideas were developed. A very great number of geologists have contributed to this understanding. In no sense is it meant to minimize the contributions to the story that have evolved in the study and mining of ores of the Andes, whose development and expansion has been nearly synchronous with that in North America - nor to minimized comparable contributions made in the late century from studies of the newer discoveries of deposits in other regions, especially the southwestern Pacific regions. In expansion of this topic, I have found that many important concepts are marked by appropriate publication but some are not, or I have not been able to discover documentation. Many notions appear to have become conventional knowledge without publication, mostly being geological viewpoints developed synchronously from similar observation. Thus, apologies are extended in advance to those whose work I have might have missed and to those unknown to me whose unpublished ideas may have seeped into the pool of common knowledge without appropriate recognition. . The analysis here addresses events of two time segments, an older one extending from the developments at Bingham in the early 1900s through the Second World War, ending about 1950; the second period extends from that time to the present. This separation is seen in Figure 1, which traces numbers of publications through the period as extracted from some 700 publications, again with a North American bias, from an annotated bibliography of porphyry copper geology in preparation. During the early period, exploration was "immature" in North America, that is, geologists looked for new districts and sites of the deposits. Outcrops were sought that carried the signatures of former mineralization and regional controls related to structural geology were closely studied. In the later period, North American exploration had "matured" into a study of districts, rather than a search for them. As the studies of these ores intensified during the younger period concommitant with increasing demands for the metal, they did so with a broadened understanding of some habits of occurrence, of hydrothermal alteration, mineral zoning, petrology, and geochemical and geophysical signatures. Outside of North America, search remained "immature" but closely related to the

Jan 1, 1997

By John L. Halls

INTRODUCTION In this section, it is assumed that the reader is an engineer with sufficient training in underground mining work, preferably with budgetary control, to understand the mining methods outlined in other sections of this handbook. The mining-method descriptions are not repeated herein; only sufficient information is provided to enable the reader to comprehend the development of the costs presented. All costs are in 1977 US dollars, except where explicitly stated otherwise. CAPITAL INVESTMENT The capital investment in the underground mining portion of any mining property includes the following: 1) The development of original access involving adits, shafts, declines, etc. It includes the necessary equipment for transporting men, materials, and rock. 2) The purchase of mine equipment including loaders, underground haulage equipment, fans, pumps, electrical distribution, surface facilities associated with the underground mine, etc. 3) Sufficient preproduction mine development to assure steadily increasing production after startup. De- pending upon the mining method used, the preproduction development should provide a supply of three months to one year of ore that is developed and is ready to be stoped. Underground development also includes excavations other than shaft stations, loading pockets, sumps, etc., which usually are associated with the means of access and are excavated by the contractor. These excavations could include a crusher cavern, an ore- storage pocket, and underground workshops that may or may not be included by the shaft-sinking contractor. Portions of these could be delayed until after production begins, but it is preferable to complete them during the development phase, so there is no interference with the production buildup. 4) The staff and labor costs for all phases from inception through final production. 5) The provision of mine-surface equipment and facilities strictly applicable to the underground portion of the operation. The required facilities include a changehouse with a lamp room, a first-aid station, compressors, an electrical substation, workshops, a ware- house, water pipelines to the concentrator, water storage tanks, explosive storage, etc. A concrete-batch plant, a sand-fill plant, and boilers for heating may be required. 6) Other direct and indirect costs. 7) Engineering, design, and procurement costs. 8) Contingency allocations. 9) Contractor's fees, startup costs, and owner's costs. Original Access As part of a study for the US Bureau of Mines, Dravo Corp. conducted an extensive literature research survey covering underground operations in the United States between 1963 and 1973. Table 1 is compiled from the section of that study pertaining to the types of access to underground mines. Table 1 does not include distances attributable to the deepening of existing shafts, nor does it include shafts bored by raise drills or downhole machines that need existing underground workings for the disposal of the cuttings. During the period under review in the report ( 1963 through 1973). concrete-lined circular vertical shafts were the predominant means of providing the first access to a new underground mine; these shafts accounted for 80% of the original access in terms of the number of accesses completed, and 75% in terms of the total verti- cal linear distances. The inside diameters of the conventional circular shafts ranged from 3.7 to 7.0 m (12 to 23 ft). Most (72% ) of these conventional shafts were for production,

Jan 1, 1982

By M. F. Bradley, G. M. Schoen

The Magmont Mine, a 50/50 venture between Cominco American Incorporated (the Operator) and Dresser Industries, Inc., (Halliburton), is a metallic mining and milling facility in the new lead belt of Missouri. The mine is located approximately 100 miles southwest of St. Louis. Legislation passed in 1992 by the Missouri legislature requires all metallic mining and processing facilities to apply for a Metallic Minerals Waste Management permit (MMWM) for their waste facilities. Regulations were subsequently promulgated by the Missouri Department of Natural Resources (DNR). Cominco obtained a MMWM permit (MM-006) from the Missouri DNR in 1992.

Jan 1, 2001

By J. A. Flinn

Phelps Dodge’s Morenci copper mine has had six drills, six track-dozers, 16 shovels, two loaders, and 90 haul trucks equipped with either Caterpillar, Aquila, or Modular GPS systems for nearly three years. The Caterpillar Computer-Aided Earthmoving System is an open-architecture system, which allows for inputs to enhance orientation solutions and system functionality. This system has begun a new phase that leads to an intelligent mining system. Optimization techniques of the current system and inputs are reviewed. In addition, some practical issues of implementing new technology in a mining environment have been identified to aid in this new phase.

Jan 1, 2000

By Peter Amelunxen, Craig Lockhart

Significant effort was made in 2003 and 2004 to upgrade the existing instrumentation and process control infrastructure at the Phelps Dodge Bagdad copper concentrator. Specifically, • cameras were installed on the feed belt for online image analysis data, • ultrasonic level sensors were installed for froth height and sump level control, • a trial froth image system was installed on one of the rougher rows, and • a new expert system to tie everything together was integrated and tuned in-house. Control philosophy, observations, opinions, and general tips and tricks are discussed with the hope of assisting other plant personnel and expert system integrators.

Jan 1, 2005

By W. L. Jacobsen, T. L. Dyer

Cortez Gold Mines completed a feasibility study for a new openpit gold mine in north central Nevada. The production schedule calls for a peak in material movement. This schedule is based on current operational efficiencies and equipment parameters observed at the company’s existing openpit operation. To mitigate risks of over/under predicting production, simulation modeling was used to validate the loading and haulage requirements during the peak production period. The advantage of simulation is the ability to provide a realistic model of a mining operation based on scheduled and unscheduled random events during the period under analysis.

Jan 1, 2007

By C. Hosten, K. V. S. Sastry, D. J. Kawulok-Englund

Introduction Since the last decade the iron ore processing industry has undergone drastic changes from supplying screened and natural ores to manufacturing tailored concentrates and pellets. Increased need for the beneficiation of lower grade iron ore deposits and the increased demand for higher grade concentrates necessitate finer grinding of iron ores before concentration. The normal filtration stations used in the past are experiencing difficulties in dewatering the finely ground concentrates to moisture levels acceptable for balling. In addition to finer grinding, applications of complex beneficiation techniques has decreased the filterability of the concentrates and create problems in filtration of iron ore concentrates. An overview of the filtration literature indicates there are few research reports on the dewatering of iron ore concentrate slurries. There exists a need to understand the principles and mechanisms involved in the filtration of iron ore concentrate slurries with a goal of developing more efficient filtration techniques. This paper presents the results from the first phase of our research program that included the development of a reproducible benchscale filtration technique and the investigation of the filtration behavior of eight iron ore concentrates.

Jan 10, 1983

By M. Yavuz

Underground mining method selection (UMMS) is one of the most important issues in mining engineering. Underground mining method should be primarily selected to make use of underground resources optimally. It is nearly impossible to change the mining method once selected by the reasons of rising costs and mining losses. Because of these reasons, UMMS process is extremely important in mine designs and economics. The strategy of underground mining method selection has been studied by different researchers in the literature. Boshkov and Wright (1973) proposed a classification system; Morrison (1976) suggested a selection chart; Laubscher (1981) proposed a selection methodology; Nicholas (1981) presented a classification system; Hartman (1987) developed a selection chart and Miller-Tait et al. (1995) modified the Nicholas? system and developed the UBC mining method selection process. In reality, UMMS is one of the important Multiple Attribute Decision Making (MADM) problems and mining engineers have always some difficulties in making the right decision in the multiple criteria environment. To make a right decision on UMMS, all known criteria related to the mining method selection should be analyzed and the problem solved according to suitable decision making techniques. A review of the literature reveals that decision making techniques have been used for UMMS applications. Kesimal and Bascetin (2002), Bitarafan and Ataei (2004), Bascetin et al. (2006), Alpay and Yavuz (2007), Karadogan et al. (2008) and Samimi Namin et al. (2008) used decision making techniques in UMMS applications. In this paper, two different MADM methods: Analytic Hierarchy Process (AHP) and Fuzzy Multiple Attribute Decision Making (FMADM) are applied to select the optimal underground mining method for a chromite mine and final solutions are then compared. THE AHP METHODOLOGY The AHP method developed by Saaty gives an opportunity to represent the interaction of multiple factors in complex unstructured situations (Triantaphyllou, 2000). The method is based on the pair-wise comparison of components with respect to attributes and alternatives. A pair-wise comparison matrix n×n is constructed, where n is the number of elements to be compared. The method is applied for the hierarchy problem structuring. The problem is divided in to three levels: problem statement, object identification to solve the problem and selection of evaluation criteria for each object. After the hierarchy structuring, the pair-wise comparison matrix is constructed for each level where a nominal discrete scale from 1 to 9 is used for the evaluation as shown in Table 1 (Saaty, 1980; Saaty, 2000). The next step is to find the relative priorities of criteria or alternatives implied by this comparison. The relative priorities are worked out using the theory of eigenvector. For example, if the pair comparison matrix is A, then, [Amax=××- [1] ] To calculate the eigenvalue ??max? and eigenvector w=(w1, w2,..., wn), weights can be estimated as relative priorities of criteria or alternatives. [ ] Since the comparison is based on the subjective evaluation, a consistency ratio is required to ensure the selection accuracy. The Consistency Index (CI) of the comparison matrix is computed as follows: [CImax--= [2] ] where ?max is maximal or principal eigenvalue, and n is the matrix size. The consistency Ratio (CR) is calculated as: [CR= [3 ] where ?RI? Random Consistency Index. Random consistency indices are given in Table 2. [ ] Table 2. The consistency indices of randomly generated reciprocal matrices As a general rule, a consistency ratio of ?0.10? or less is considered acceptable. In practice, however, consistency ratios exceeding ?0.10? occur frequently. THE FMADM METHODOLOGY The FMADM methods have been developed due to the lack of precision in assessing the relative importance of attributes and the

Jan 1, 2009

By L. L. Chasko

A mine fire is one of the most challenging safety issues facing a mine operator and can occur at any location underground. The National Institute for Occupational Safety and Health (NIOSH) and the Twentymile Coal Mine, Colorado, conducted in-mine experiments to determine the capability of high-expansion foam for addressing underground fires. The tests were conducted in sloping entries with high-capacity diesel-powered foam generators. The following results were observed: a well-designed, maintained, and properly operated high-expansion foam generator can propagate a foam plug hundreds of feet in steep upward sloping (20 pct) multiple entries against a ventilation pressure; stoppings and partitions designed to contain the foam plug in upward sloping entries must be substantially constructed; and the predicted quantity of foam concentrate can be significantly less than the actual amount used due to foam losses, such as bubble breakage on dry surfaces. This paper describes the production of high-expansion firefighting foam and discusses the in-mine experimental tests and results. DISCLAIMER: The findings and conclusions in this report are those of the author(s) and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

Jan 1, 2009

By Steve Kral

In a lagging economy where profits are tight, businesses cut costs. No revelation there. The mining industry, though, has always looked for ways to reduce production costs — no matter the state of the economy or commodity prices. The fact is, when planning a new mine or the expansion of an existing one, mining companies gamble that commodity prices will be reasonably high when a project comes onstream. It takes millions of dollars and several years to bring a mine into operation. And a lot can happen economically between the time management gives the go-ahead for a new project and its completion.

Jan 1, 2002

By Augustine O. Orumwense

Ball mills are commonly used for regrinding operations in the mineral processing industry. But, in recent times, efforts are being made at the introduction of stirred mills particularly for those instances where very fine grinding is required. Media type (steel shot, glass beads, alumina balls and crushed quartz), media size, mill speed and the number of passes required to obtained the target product size are studied. The product size and energy consumption are used in the evaluation of the test results. The grinding media size, shape, density, filling ratio, mill circumferential speed and grinding time play a distinct role in product size fineness.

Jan 1, 2005

Your assessment of the minerals business. The global mining industry is strong. I am convinced it will continue meeting the mineral needs of the world population for the foreseeable future. Two developments have greatly enhanced the industry’s ability to produce low-cost minerals. Technological innovations have resulted in increased productivity. And there has also been a dramatic expansion of the number of favorable countries in which to explore and mine. Capital expenditures have flowed to the low-production-cost mines and development projects as well as to the exploration projects and stable countries having the best potential for valuable mineral discoveries.

Jan 1, 2000

By Jim Rozek, Robert A. Gee

The Epping to Chatswood Rail Line project is the largest publicly funded infrastructure project in New South Wales. Construction commenced in November2002 with opening scheduled for 2008. The work includes 13 route km of twin TBM driven 7.2 m diameter lined running tunnel, three cross-overs and three new underground stations. The new stations have platform caverns of 20m span with similarly proportioned concourse caverns alongside. The ground is bedded sand stone and shale with high horizontal stresses. Predicted stress-relief induced ground movements during staged excavation led to innovative use of rock anchors for permanent support.

Jan 1, 2005