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By Peter Allen, John R. Stuermer

COUNTRY RISK ANALYSIS A company operating in a foreign country assumes all the risks that it would at home. However, beyond these, it assumes risks that arise from the unique political economic, financial conditions of the foreign country which it operates. These risks are known as "country risks". The importance of these risks has grown appreciably in the recent past (particularly in the aftermath of Iran's revolution in the late 1970s and Mexico's debt rescheduling of 1982-83), and as a result, country risk analysis has become an increasingly useful management tool. Country risk analysis seeks to assess the probability that countries will service their aggregate foreign liabilities on time, as well as the probability that country conditions could inhibit the debt service capability of private sector debtors. This involves assessment of both the ability and the willingness of countries to meet their external liabilities in a timely fashion. "Ability" is linked economic and financial variables: principally, a country's economic structure, foreign exchange generating capacity and debt service burden. On the other hand, "willingness" is tied to political factors: mainly the economic/financial orientation of government policy and the stability of economic decision making. Ability: Economic, Financial Conditions and Prospects Judgement of a country's ability to meet foreign financial obligations begins with a detailed study of a country's external balance sheet which compares the country's foreign liabilities and assets. Table 1 below presents country balance sheets for Mexico, Korea and Indonesia. [TABLE 1 The External Balance 3-,-et 1983 (billions of dollars; Indonesia Mexico Korea Foreign Liabilities 31.1 67.6 40.5 By Source: Bank 13.1 75.5 26.3 Non-bank 18.0 12.114.2 Foreign Reserves 9.3 4.7 7.0] The large magnitude of Mexico's external debt (nearly $90 billion), compared to foreign assets of approximately $5 billion, illustrates the weakness of this country's external payments position, and the main reason that it has been unable to meet interest and principal payments and been forced to reschedule its foreign debt. On the other hand, the relationship between Korea's external liabilities and assets ($50.5 billion and $7 billion, respectively), is more favorable and helps explain why Korea has been able to meet debt service payments and maintain its access to the international capital markets. Indonesia has even a more favorable relationship between its foreign assets and liabilities, $31 billion and $9 billion, respectively, and its debt is mostly lower interest rate, non-bank debt, making for a less onerous debt service burden. After the balance sheet, the analysis turns to a comparison of the country's foreign exchange earning capacity and its prospective financing requirements, that is, the country's future earnings stream

Jan 1, 1985

By Richard N. Appling

This compilation presents information obtained through investigation of manganese deposits and a reconnaissance of potential manganese-bearing areas of southwestern Oregon and Del Norte County, Calif., from October 1952 to September 1955. The report includes maps, assays, and preliminary examination data on 39 manganese deposits distributed throughout Curry, Coos, Douglas, Josephine, and Jackson Counties, Oreg., and 1 deposit in Del Norte County, Calif. On the basis of mineral content the deposits can be divided into three groups: 1 Manganese silicate deposits, manganese oxide deposits, and manganiferous iron de-posits. Generally the oxides occur along the coast in the Curry-Coos County area, the manganiferous iron deposits are in the Josephine-Douglas area, and the manganese silicates are found in both the Josephine-Douglas and Jackson County areas. The deposits are characteristically irregular in form and usually small. Most silicate and manganiferous iron deposits are in metasediments of Triassic (?) age; oxide deposits are in sediments varying in age from Jurassic to Eocene.

Jan 1, 1957

By W. M. Traver, A. M. Evans

"INTRODUCTION The Bureau of Mines undertook exploration in the Torlingua district, Texas, during June 1943, at a time when the demand for mercury for war industries was considerably more than the anticipated domestic production. In view of the impressive past production of the mines and the favorable geologic conditions in several underdeveloped areas in the district, the investigation was considered of immediate importance.Prior to initiation of the exploratory program, a preliminary examination of the district was made in August 1942 by A. B. Needham, an engineer of the Bureau of Mines. This examination was followed by a comprehensive geological study by the Federal Geological Survey 3/ and further investigation the Bureau of Mines."

Jan 1, 1947

By J. J. Jonas, G. Gagnon

SHG zinc was extruded in the temperature range 110" to 350°C and the strain rate range 0.05 to 5 sec-1 The strain rate/flow stress/temperature results were analyzed using a power sinh stress relationship. When temperature changes due to the heat of deformation and to heat losses are neglected, the exponent of the sinh function of the stress is 5.6, and the apparent activation energy of deformation is 28 kcal per mole. When these changes are taken into account, the exponent decreases to 4.7 and the activation energy to 23 + 2 kcal per mole. The corrected stress exponent and activation energy are in very good agreement with published values obtained from creep experiments, and suggest that the hot extrusion of zinc is controlled by a mechanism involving self-diffusion. When the extrusion and creep data are compared using a Zener-Hollomon parameter and either a sinh or an exponential stress term, an appreciable offset is observed, which may be due to the difference in impurity content. For a given set of extrusion conditions the ram speed, maximum pressure, and initial temperature can also be correlated using a Zener-Hollomon parameter and a sinh pressure term. THE deformation of metals at temperatures over about one-half the absolute melting temperature has been extensively studied at creep strain rates. By contrast, relatively little work has been carried out on the behavior of metals at hot working strain rates. Most of the latter investigations have been performed using simulative methods, such as hot torsion and hot compression, in which the friction conditions and temperature rise during deformation may differ appreciably from those existing under industrial conditions. Recently, however, Wong and Jonas1 used a scaled-down industrial process to determine the stress and temperature dependence of the strain rate during the extrusion of aluminum. In such tests, the effects of friction and adiabatic heating are closer to those produced in industrial operations. Also, with regard to the testing of materials of limited ductility such as zinc, hot compression and hot torsion do not permit the attainment of true strains as large as the deformations usually applied commercially. The present study was undertaken to investigate the extrusion behavior of Special High Grade (SHG) zinc. The detailed objectives were: 1) to establish the stress and temperature dependence of the strain rate with and without a consideration of adiabatic heating, 2) to study the pressure and temperature dependence of the ram speed, and 3) to investigate the microstruc- tural changes occurring during the deformation. The last aspect of the investigation will be covered in a separate paper. The treatment described below differs from that of Wong and Jonas in that the adiabatic temperature rise during deformation is taken into account, and the calculation of the mean equivalent strain rate is based on the redundant as well as on the homogeneous work. EXPERIMENTAL PROCEDURE Rods from two shipments of continuously cast SHG zinc* were used in the investigation. The composition *Supplied by courtesy of Cominco Ltd. range of the impurities present, as given by the supplier, was: Pb: 0.0013 to 0.0023 pct, Fe: 0.001 pct max Cd: 0.0001 to 0.0006 pct, Cu: 0.0002 to 0.0005 pct, Ti: 0.0001 pct max; thus, by balance, zinc valued from 99.9963 to 99.9966 pct. The as-received rods were machined into billets having a nominal diameter of 1.56 in. and a nominal length of 1½ in.; longer billets up to 4 in. in length, were also used to investigate special aspects. The as-machined rods were annealed at 400°C for 24 hr and slowly cooled. This treatment produced a columnar grain structure, with a grain size of about $ by 2½ cm which was appreciably larger than the as-cast one. A 150-ton, direct extrusion, vertical press was used. Ram displacement and force were recorded continuously against time. A constant flow control valve permitted the maintenance of a range of preselected ram speeds up to in. per sec. The selected speed was held constant, irrespective of the required force, as long as the load developed was below the maximum available. Strain gages were used to determine the force; the gages were calibrated before and after each testing period with a 200,000-lb capacity load cell. Further details of the experimental equipment can be found in Ref. 2. The billets were preheated for 90 min in the extrusion container, which was well insulated so as to minimize temperature gradients. This period was sufficient for the billet to reach a uniform temperature at all temperatures between 110" and 350°C. A square-shoulder die having a 0.290-in. diam central hole was used. The extrusion ratio was 30 to 1. This is equivalent to a reduction in area of 96.7 pct, an elongation of 2900 pct, and a true strain of 3.4. The ram speed was varied over two orders of magnitude from 0.0027 to 0.26 in. per sec. The ram was water-cooled during most of the tests, although some experiments were conducted with a preheated, uncooled ram. All extrusions were run without lubricant, which resulted in conditions of sticking friction. EXPERIMENTAL RESULTS Stress Dependence of the Strain Rate Neglecting Adiabatic Heating. The maximum force required to extrude is given in Table 1 for each of the five initial

Jan 1, 1970

By R. S. Douglas

Introduction During the past few years, a number of changes in the mine operations at Copper Mountain have taken place. The modernization and mechanization were necessitated and given impetus by wartime and other conditions, which were: (1) The urgent need for copper for wartime purposes. (2) The scarcity of skilled labour for underground work. (3) The increase in labour and supplies cost. (4) The necessity of finding ways and means of increasing the output per man-shift, because of the scarcity of skilled labour and the rising cost of labour. (5) The desire to increase safety measures, reduce the silicosis hazard, and aid mine ventilation. (6) The desire to improve the general working conditions in the mine for all workmen. (7) The desire to reduce the amount of dilution in the ore stream by a more selective yet highly productive method of mining. To this end, mining with diamond drills, and transferring broken ore with slusher hoists, appeared to be the answer to the problem. After considerable discussion and estimation of costs for comparison with those of the operation as carried on at that time, the proposed methods were tried out and, in practice, gave very gratifying results. Reference at this point is made to the paper written by C. H. Brehaut, W. N. Taylor, H. A. Shannon, and R. S. Douglas, which was published in the September, 1945, issue of Mining Technology, by the American Institute of Mining and Metallurgical Engineers, Inc., and subsequently in commercial mining journals. Since that time some improvements have been made in undercutting an orebody - the first through experiment and practice, the second through making use of the earth's barodynamic or gravitational forces. It is the purpose of this paper to describe and discuss these later developments.

Jan 1, 1947

By Stephenson. E. L.

"INTRODUCTION In the spring of 1942 a series of magnetometer surveys on deposits of black sand underlying Pleistocene raised marine terraces along the coast of southwestern Oregon was nada by the Division of Geophysical Exploration of the Federal Bureau of Mines in cooperation with the Oregon Department of Geology and Mineral Industries. A few preliminary tests had been made in the same area in May 1940 and December 1941.The sands contain fine gold and metals of the platinum group, and, beginning in 1852, extensive, but spasmodic mining and exploration have been done for these precious metals. There are many old placer, mines and prospects, although for the most part the yield of the metals has been small. The sands also contain other minerals of potential value, including ilmenite, magnetite, garnet, zircon, and particularly chromite, and the wartime demand for domestic chromite resulted in extensive testing and development of the known deposits. The purpose of the magnetometer surveys was to determine the efficacy of, magnetic methods in tracing and outlining these known deposits and in prospecting for new ones. The field work was done between March 17 and May 29, 1942, by the author assisted by W.W. Paulsen of the Oregon Department of Geology and Mineral Industries."

Jun 1, 1945

By McHenry Mosier

This paper constitutes the third progress report on a national survey of the use of detachable bits in metal mines. It presents comparative costs of drilling with conventional and detachable bits and describes the operating practice in rock drilling and the reconditioning of drill steel and bits at 10 mines not discussed in previous reports.3/ ACKNOWLEDGMENTS This report has been prepared with the assistance and cooperation of the officials and staff members at the mines visited. Costs and other data at individual mines were developed and furnished by the operators.

Jan 1, 1937

By D. H. Horswill

Red Dog, the world’s largest zinc mine, is located ninety miles north of the Arctic Circle in northwest Alaska on lands owned by the Inupiat Eskimo organization called NANA. NANA received a subsurface title over this resource as part of their settlement lands under the Alaska Native Claims Settlement Act and subsequently entered into a Lease Agreement with Cominco in 1982. Cominco, an international mining company focused on zinc, built and operated the mine. NANA’s principle objective in the development of the mine was to have it contribute to the development of sustainable communities within their traditional region. This meant creating job opportunities in a modern economy while preserving the traditional subsistence lifestyles. Preservation of their culture, language, and traditions are as important to the NANA people today as they were through ages past. The principles of sustainable development – matching economic, environmental, and social goals through continuous communications and high commitment to efficient and effective operations – have been core values for the Red Dog Mine from the beginning. This paper will describe how a large mining operation in a remote corner of the world has been able to contribute toward sustainable development in that region.

Jan 1, 2000

Invensys’ recently introduced Field Device Manager for Foxboro I/A Series distributed control systems provides the industry’s first solution that takes advantage of both the latest Enhanced Electronic Device Description Language (Enhanced EDDL) and FDT technologies. This combination provides comprehensive lifecycle support to configure, calibrate, commission, diagnose and optimize the performance of any vendors’ foundation fieldbus device. The I/A Series Field Device Manager enables users to take advantage of any EDDL, Enhanced EDDL and/or FDT host deliverables supplied by the device vendor.

Jan 1, 2007

By R. J. Hundermark, L. R. Nelson

The critical importance of tap-hole design and management to furnace performance and longevity is explored through examining some of the specific matte, metal and slag tapping requirements of non-ferrous copper blister and matte converting and smelting, ferroalloys smelting and ironmaking systems. Process conditions and productivity requirements and their influence on tapping are reviewed for these different pyrometallurgical systems. Some critical aspects of the evolution of tap-hole design to meet the diverging process and tapping duties are examined. Differences and similarities in tapping practices and tap-hole management are reviewed. Finally core aspects of tap-hole equipment and maintenance are identified that are considered important to securing improved tap-hole performance and life, so pivotal to superior furnace smelting performance.

Jan 1, 2014

By Lynn B. Hales

Unfortunately, the term "control" has a negative connotation in the minds of many of our operating plant personnel. Whereas the opposite is true of those associated with research and technical centers in our industry. The magnitude of this difference in opinion and actual experience has often proved to be a major factor influencing the success or failure of process control applications. Through the years, many plant people have endured a number of unsuccessful attempts by "outside" people to "optimize" their plants; and these experiences have proved to have had quite a callousing effect on them. On the other hand, in many plants, successful process control efforts have made firm allies of the operating personnel, and have increased the number of metallurgical people who are well qualified and experienced in process control. The instrumentation industry, computer industry, and the mining industry's ability to quantify what is really happening in our processes have grown and developed rapidly since the first control efforts were made in the 1930's (1). Because of this-,: new control opportunities are becoming increasingly more feasible and older well established ones are becoming even more practical and necessary with regard to the economic s of our industry.

Jan 1, 1979

By Robert J. Timkp, James D. Noll, Peter Hall, Robert Haney, Linda McWilliams

Diesel particulate matter (D PM) samples from underground metal/nonmetal mines are collected on quartz fiber filters and measured for carbon content using National Institute for Occupational Safety and Health Method 5040. If size-selective samplers are not used to collect D PM in the presence of car-bonaceous ore dust, both the ore dust and D PM will collect on the quartz filters, causing the carbon attributed to D PM to be artificially high. Because the D PM particle size is much smaller than that of mechanically generated mine dust aerosols, it can be separated from the larger mine dust aerosol by a single-stageimpacto1: The SKC D PM cassette is a single-stage impactor designed to collect only D PM aerosols in the presence of carbonaceous mine ore aerosols, which are commonly found in underground nonmetal mines. Howeve1: there is limited data on how efficiently the SKC D PM cassette can collect D PM in the presence of ore dust. In this study we investigated the ability of the SKC D PM cassette to collect D PM while segregating ore dust from the sample. We found that the SKC D PM cassette accurately collected D PM. In the presence of carbon-based ore aerosols having an average concentration of 8 mg/m3, no ore dust was detected on SKC D PM cassette filters. We did discover a problem: the surface areas of the D PM deposition SKC D PM cassettes, manufactured prior to August 2002were inconsistent. To correct this problem, SKC modified the cassette. The new cassette produced, with 99% confidence, a range of D PM deposit areas between 8.05 and 8.28 cm2, a difference of less than 3%.

By Tapio Ahokainen, Asmo Vartiainen

"Outotec's portfolio contains a wide variety of smelting solutions for non-ferrous metals. Some of these include flash smelting for primary copper and nickel, flash converting for copper, Ausmelt technology for primary and secondary copper, nickel, tin, lead, and zinc residues and waste, Kaldo technology for secondary copper, lead, and precious metals recovery. Outotec also offers slag cleaning technologies and much more.Company provides complete process solutions tailored to each customer's individual needs. Decades of experience have resulted in extensive metallurgical know-how that ensures the most profitable process choice and optimal performance. Outotec's life cycle technology partnership with their customers spans from the early stages of process solution design through the supply and commissioning of the entire process chain. They include integrated process control and holistic service and support concepts. Continuous research and development ensures that the customer is provided with the latest advancements in process and equipment solutions.IntroductionOutotec develops and provides technology solutions for the sustainable use of the Earth's natural resources. Solutions are ranging from various processes and special equipment needed for metallurgical extraction and mineral processing of ores to the production of refined metals and minerals. The processes include not only the grinding and physical separation of ores but also the smelting and leaching of base metals and precious metals. The company provides engineering services for whole projects as well as life cycle services on the equipment and products that they supply."

Jan 1, 2012

By Wedam Nyaaba, Samuel Frimpong, Bruno Ayaga Kansake, Irene Akalanyaba Ateng

Haul truck capacities have increased due to their economies of scale in large-scale surface mines. These high-capacity trucks impose dynamic loads on haul roads. A previous study estimated the dynamic forces imposed by ultra-large trucks on haul roads to be more than three times the static load. These dynamic forces exacerbate haul road stresses and deformation. Current haul road response models are 2D and use static truckloads for low-capacity trucks. No models capture the ultra-large truck dynamic effects on haul road structural response. This study uses 3D finite element (FE) modeling to compute the haul road response to ultra-large truck dynamic loading. The dynamic forces were modeled using multibody dynamics (MBD) in MSC.ADAMS. These forces were used in an FE model developed, verified, and validated in ABAQUS, to simulate the response of the haul road to the dynamic truck forces. The road was modeled using an elastoplastic Mohr-Coulomb model. The results showed that road deformation decreases with increasing layer modulus and increases with increasing payload. Increasing the base modulus from 100 MPa to 450 MPa reduced the maximum deformation from 258 mm to 62 mm. When the subbase elastic modulus increased from 100 MPa to 500 MPa, the maximum deformation decreased from 160 mm to 84 mm. Increasing the payload from 0 to 120% of the rated load increased the maximum wearing surface deformation from 131 mm to 216 mm. This study forms a basis for designing structurally competent haul roads for improving haulage efficiency and truck and operator health.

Jan 7, 2023

By J. C. Agarwal

Slags produced by modern smelting furnaces contain copper values which are unacceptably high for discard. The electric arc furnace is employed commercially to clean copper from flash furnace slags but the addition of highly oxidized converter slags to an electric furnace has created operational problems. Highly oxidized Noranda Reactor slags have not been processed successfully in a pyrometallurgical process. These slags, which contain large concentrations of copper (5 to 10 per cent), are treated in slag concentrators (controlled cooling, crushing and milling, and flotation) which produce a copper concentrate that must be resmelted. Though commercially operable, it will be shown that the slag concentrator has important process and cost disadvantages as compared to a pyrometallurgical process. In this paper an economic comparison is made between a pyrometallurgical process and the slag concentrator. For the analysis, five hypothetical smelting plants are considered. Each plant treats 1200 tons of copper concentrate per day and produces 109,000 tons of copper annually. The plant configurations used in this study are:

Jan 1, 1976

By William S. Roberts

The Bureau of Mines has initiated a program to determine the availability of land for mineral exploration and development in Alaska. Researchers involved in this pro-gram are comparing land availability, based on ownership and government policies and regulations, to the distribution of known mineral deposits and terranes. This report on southeastern Alaska presents the findings of the first of six regional studies that will cover the State. The study consisted largely of data compilation and analysis using various mapping techniques. Summary land availability data are presented on copies of U.S. Geological Survey (USGS) quadrangles at a scale of 1:500,000. Five categories of land availability were identified: open to mineral exploration and development (approximately 9.4 million acres, or 38% of the 24.8-million-acre study area), open but with possible use restrictions (4.2 million acres, or 17%), selected (0.5 million acres, or 2%), patented (0.74 million acres, or 3%), and formally closed to mineral exploration and development (10 million acres, or 40%). Of the 1,187 known mineral deposits in the study area, approximately 38% are on land in the open category. Mineral terranes comprise approximately 6.7 million acres, or 27% of southeastern Alaska. Approximately 34% of these terranes are on open land.

Jan 1, 1985

By Leonard F. Heising

At the Groveland-mine iron ore is mined by open-pit methods and concentrated by means of spirals and flotation. A brief history of the mine and its early development is given. The ore deposit is described, with emphasis on those physical characteristics that affect the choice of mining and milling methods. Development and mining, which include breaking ground, loading, transportation, engineering, and operating control; are explained, and the milling method is described Mining and milling costs are given in percent of total cost.

Jan 1, 1963

By Daniel Harrington

On the night of June 8, 1917, the flame of a carbide lamp accidentally set fire to the uncovered and frayed insulation of an armored power cable near the 2,400-foot level of the North Butte Mining CO.'s Granite Mountain shaft. How this, insulation accidentally became exposed is explained on page 15. The highly flammable oiled fabric set fire to the shaft timbers, and as this is a downcast shaft the fire spread with great rapidity, soon filling the mine workings with smoke and gas. At the time 410 men were working underground, 247 of whom escaped by various means, but most of the 163 remaining were probably overcome soon after the fire started, and perished. Only two men were actually burned. The cause of the disaster was purely accidental. The immediate effect was the unexpected reversal of normal conditions; the ultimate effect was great loss of life and the destruction of the main hoisting shaft, putting it temporarily out of service. The work of rescue and fire fighting continued eight days. The following pages present an attempt to draw some practical conclusions and suggestions from this disaster. The property of the North Butte Mining Co. consists of about 220 acres in the northeastern part of the Butte district, Montana. Next to the Anaconda Copper Mining Co. it is the largest producer of the district. In 1916, the year before the disaster, there were 1,160 men employed. The output was 560,947 tons of ore, which yielded 24,498,181 pounds of copper, 1,047,063 ounces of silver, 1,712 ounces of gold, and 412,953 pounds of zinc. The profit was $2,479,595. The total development work for that year was 21,694 feet. During the first half of 1917, the year of the accident, the daily tonnage of ore averaged 2,000, an increase of 400 tons over that of the year 1916.

Jan 1, 1922

By E. R. Cole

One objective of Bureau of Mines recycling research is to devise technology that enables recovery of metals and minerals from wastes. From October 1982 through September 1985, researchers at the Bureau and at the University of Missouri Rolla (contract H0222002) investigated the use of nonferrous flue dust with varying Zn contents (11 to 66 pct) as a source of Zn for electrogalvanizing steel wire. The waste dusts used were from a secondary Cu smelter, a brass smelter, a Pb smelter, and a water treatment plant. The dusts were leached in H2S04, and the leach solutions were treated to make electrolyte for electrogalvanizing steel wire using soluble Zn anodes. Cyclic voltammetry was used in an inno-vative method to evaluate the quality of the electrolytes used for elec-rogalvanizing. After electrogalvanizing, the wire was drawn on a labo-ratory draw bench to simulate industrial practice. Corrosion resistance was measured by a number of electrochemical techniques and by the stan-dard ASTM salt-spray tests. After successful bench-scale tests, the process was demonstrated in an industrial pilot plant. Results indicate that nonferrous flue dusts can be used as a source of Zn for electro-galvanizing if certain impurities are either partially or completely removed from the starting electrolyte.

Jan 1, 1987

By Bolmerm R. L.

This information circular describes the application of modern methods and equipment in sinking a vertical, 916-foot-deep by 16-foot-diameter, concrete-lined access shaft for the Harold D. Roberts tunnel near Montezuma, Colo. Although the access shaft was merely a construction facility to expedite completion of a 23-mile water-diversion tunnel, a circular shaft of this type would be equally adaptable for mine development or other purposes. Comparable sinking methods and equipment could be used for similar shafts within a wide range of sizes and depths. SUMMARY In addition to excavation and support of the basic access shaft to tunnel grade, the overall sinking project involved initial preparation of a surface site and plant, subsequent construction of a tunnel-level station and loading pocket at the shaft bottom, and ultimate conversion of the basic shaft into a hoisting and access facility for tunnel operations. The sinking period for the basic shaft approximated one year. Actual tunnel operations through the converted shaft began on April 3, 1958, approximately 19 months after the project was initiated.

Jan 1, 1961