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Mining projects draw together stakeholders with various degrees of experience in managing and assessing financial risk. When this risk is not fully appreciated or quantified, the potential for making decisions not suited to investor requirements is significantly increased. A feasibility study provides key information on project development potential, requiring detailed technical investigations with thorough financial analysis. Centaur Mining and Exploration (CME) owned and operated Cawse Nickel Operations (CNO), one of three Australian projects to develop and process vast amounts of near surface nickel resources. A technical ædue-diligenceÆ and æbankable feasibility studyÆ confirmed the large resource base, newly applied yet tested technology and relatively low unit costs would produce nickel in the lower half of industry operating costs. A number of production variables including capital requirements, delayed start-up, nickel grade, processing, maintenance and product output were outside the feasibility estimate. This was combined with exchange rate fluctuations and lower Ni prices. The inability to generate adequate cash flow and service debt repayments ultimately led to receivership and liquidation of all assets. Following the sale of CentaurÆs gold and nickel divisions, $A 784 million remained outstanding to creditors. This paper aims to define key issues leading to CNOÆs collapse by reviewing feasibility parameters, valuation methodology and project development. Some methods of assessing project viability are discussed with the aim of increasing stakeholder risk awareness.

Jan 1, 2003

By Charles W. Daugherty, Eugene B. Waggoner

In the construction of recent subsurface projects, particularly mined openings and transit systems, it has been apparent that final costs were often greater than first expected. Because many overruns result from alleged differing site conditions, there was reason to suspect that pre-bid geotechnical investigations were inadequate for predicting subsurface geology. In 1982, nine federal agencies involved in constructing underground facilities funded the National Academy of Sciences' U.S. National Committee on Tunneling Technology (USNC/TT) in an effort to evaluate and clarify the relationship between geological knowledge and construction costs. That committee formed the special Subcommittee on Geological Site Investigations, which spent more than two years studying underground projects by examining contract documents and geologic reports, making site visits, and interviewing owners, designers and contractors. The study ultimately encompassed 84 mined tunnels and chambers and three deep shafts in the United States and eastern Canada. Data collected on geologic exploration, design and construction were analyzed and conclusions reached concerning whether and how site investigations need to be improved. The results of the study are published in two volumes by the National Academy of Sciences. Due to the recent completion date of the main report, it was not possible to prepare a summary for inclusion in the RETC Proceedings. However, the complete two-volume report, "Geotechnical Site Investigations for Underground Projects," can be obtained by writing or calling: U.S. National Committee on Tunneling Technology National Academy of Sciences 2101 Constitution Avenue, N.W. Washington, D.C. 20418 (202) 334-3136

Jan 1, 1985

By Mark Colwell, Russell Frith

This paper summarizes the results of a research project whose goal was to provide the Australian coal industry with a chain pillar design methodology readily usable by colliery staff. The project was primarily funded by the Australian Coal Association Research Program and further supported by several Australian longwall operations. The starting point or basis of the project was the Analysis of Longwall Pillar Stability (ALPS) methodology. ALPS was chosen because of its operational focus; it uses tailgate performance as the determining chain pillar design criterion rather than simply pillar stability. Furthermore, ALPS recognizes that several geotechnical and design factors, including (but not limited to) chain pillar stability, affect that performance. There are some geotechnical and mine layout differences between United States and Australian coal fields that required investigation and, therefore, calibration before the full benefits offered by the ALPS methodology could be realized in Australia. Ultimately, case history data were collected from 19 longwall mines representing approximately 60% of all Australian longwall operations. In addition, six monitoring sites incorporated an array of hydraulic stress cells to measure the change in vertical stress throughout the various phases of the longwall extraction cycle. The sites also incorporated extensometers to monitor roof and rib performance in response to the retreating longwallface. The study found strong relationships between the tailgate stability factor, the Coal Mine Roof Rating, and the installed level of primary support. The final outcome of the project is a chain pillar design methodology called Analysis of Longwall Tailgate Serviceability (ALTS). Guidelines for using ALTS are provided.

Jan 5, 1999

By K. Chandrasekaran

Carbon-in-leach (CIL) is conventionally used in gold processing operations when preg robbing components are present in the ore. The CIL process is becoming attractive even in other situations when preg robbing is not a factor. This article discusses the situations in which the CIL circuit can be applied. The results of leach-carbon-in-pulp (CIP) and CIL circuits at Newmont Gold's Mill No. 2, No. 4 and No. 5 are presented for comparison: Mill No. 4 was initially designed for a throughput of 4.1 kt/d (4500 stpd). It is presently operating at an average throughput of 6.6 kt/d (7300 stpd) without significant changes to the original design. The design considerations of the Mill No. 4 CIL circuit are discussed. The design of any processing facility represents a series of decisions. The final design options should ultimately be resolved based on economic as well as technical considerations. Every design decision represents some sort of compromise. From the designer's view point, these decisions are made with the conviction that the final product represents the most prudent long-term expenditure. The design throughput rate is a decision reflecting a maximum return for the capital and operating costs that the plant will incur over the life of the mineral resource. The result is a plant that is not operator proof or maintenance free because it would be too costly to build. At some point, the incremental increase in the level of capital expenditure would not adequately compensate for the lower

Jan 1, 1991

By S. C. Suboleski

Underground long-range planning and mine design is an iterative process beginning with a specified production level, quality criteria, and geology of the deposit. Given these factors, face equipment is selected, the number of units needed and production per unit are calculated, and the mine infrastructure needs are developed. The scheduling of units then follows, with the design of the various support systems coming next. The support systems needed to maintain production can be grouped as follows: (1) outby haulage of mined material, (2) supply and manpower haulage, (3) ventilation and associated environmental considerations, (4) drainage, fresh water, and related considerations, (5) rock mechanics, and (6) power, supply. Thus, long-range planning may be viewed as a three-tiered structure, with the data on required production, product quality, and geology at the upper level; the development of face production capacity and the scheduling of units sufficient to meet the needs of the first two at the second level; and the development of support operations for the production units at the third level. Changes at any level may affect not only the items on that tier but may also cause a change to the items on the tier above and below. For example, if the rock mechanics data indicate that desired opening sizes will not be stable, then this situation will affect not only the ventilation design but also the production rate and possibly the selection of equipment itself. These, in turn, may affect the scheduling of units and the number of units, ultimately influencing the entire third tier of systems.

Jan 1, 1979

By W. A. Goodyear

It is safe to assert that in cities generally, the fuel of the future for all domestic, as well as for most manufacturing and metallurgical purposes, will be gaseous fuel. The immense advantages which gas possesses in facility and cheapness of distribution, cleanliness, and economy of manipulation, and the facilities which it offers for utilizing in almost all cases a much higher percentage of the total quantity of heat produced, than it is possible to do with any kind of solid fuel, are facts which will vastly more than compensate for the comparatively small loss of heating power, which will be found necessary in the turning of the solid fuel into gas upon a large scale, and which, in the bpinion of the writer, will, at no distant day, command attention, and will ultimately result in a revolution in our use of fuel. The employment of gaseous fuel upon a scale of any considerable magnitude, has hitherto been almost entirely confined to the utilization of the waste gases of the iron smelting furnace for heating the blast, and the rapidly increasing use, for certain metallurgical pur-

Jan 1, 1883

By Robert Glass Cleland

THOUGH the rapid revival of the copper market in the early twenties solved the most serious of the company's immediate postwar difficulties, a much more fundamental, long-range problem still remained. Mining is not like farming: the earth does not bring forth a new crop of gold, silver, lead, zinc, oil, or copper at every harvest time. Metal taken from the ground does not spring up again from the old roots like perennial flowers in a garden, or find renewal in freshly sown seed. No ore body, whatever its size or richness, is too big or too rich to escape ultimate exhaustion. When the war closed in 1918, Phelps Dodge had been mining copper from Bisbee, Morenci, and Nacozari over periods varying in length from ten to nearly forty years. During much of that time, the company's production had run from fifty million to as high as two hundred million pounds a year. Even the greatest of mines had to respond in time to such a drain. High grade ore was already at a premium in Bisbee and Morenci. The Burro Mountain properties of New Mexico were a disappointment. Failing the acquisition of

Jan 1, 1952

By Nick Barton

Simple methods for estimating the shear strength of rock joints and waste rock are reviewed. For the case of rock joints, the methods are based on a quantitative characterization of the joint roughness and the joint wall strength. Size-effects are found to reduce the peak strength of large joint samples to values below the ultimate or so-called "residual" values measured in the laboratory. Tilt tests and surface profiling on natural size blocks within the jointed rock mass are recommended for obtaining scale-free properties. The joint parameters obtained can be used to model complete strength-displacement-dilation behavior if this level of input is required. Large scale tilt tests can be performed with advantage on both rock joints and waste rock. The behavior of these two materials is surprisingly similar. Both are influenced by the size-effects on the compression strength of the rock, and both have similar log-linear relationships between effective normal stress and the peak drained friction angles. The resulting high values of friction near the toe or close to a slope face in either material can be misleading.

Jan 1, 1983

By R Willis, D Cooke, G J. Davidson

Mine-groundwater interaction at the Pasminco Rosebery Mine (PRM), western Tasmania, deserves special attention due to the unique climate and mining environment present. High rainfall and low evapotranspiration result in an excess of water, an uncommon problem at Australian sulfide bearing mines. Research is being undertaken to delineate current subsurface fluid flows and predict future fluid flows in order to improve management after mine closure. Acid mine drainage generation is well developed in abandoned mines throughout the area. If acid mine drainage is not controlled after mine closure, significant environmental degradation could occur in the receiving waters of the Pieman River system. The study area encompasses the heavily forested Mount Black, and underlying PRM workings. Groundwater flows beneath Mount Black through a crystalline fractured rock aquifer with faults and underground mine workings observed to act as the major hydraulic conduits. Recharge is controlled by local precipitation, and the ultimate discharge is thought to be the Pieman River system, which forms the topographic low in the area. Slug tests have been used in conjunction with the mineÆs extensive geotechnical database to spatially evaluate variation in hydraulic conductivity. In fractured rock terrain associated with mining, rock quality designation data can be a useful tool in delineating areas of similar hydraulic conductivity when combined with conventional hydrogeological methods. A GIS, mine planning software, an environmental and a geological database are linked to form the input for groundwater modelling.

Jan 1, 2003

By M. K. Gangal, E. D. Dainty

CANMET/MRL has been contributing to an industry/government program to assess the quality of air in mines, and improve the working environment for Canadian miners. The ultimate aim of this program is to recommend a sampling methodology and appropriate concentration limits for both the soot (diesel particulate matter - DPM) generated by diesel equipment, and respirable combustible dust (RCD) as measured underground. The program was conceived by the Canadian Adhoc Diesel Committee, which consists of representatives from seven major Canadian mining companies, three provincial inspectorates, one union representative, two manufacturers of diesel equipment, and CANMET, a Federal Canadian research agency. This paper describes the modification and laboratory confirmation of an existing methodology for the sampling and analysis of DPM/RCD, including: sampling problems, filter selection, filter efficiency, DPM size distribution, the approximate performance of fractionating devices, and it reports the results of current ambient measurements of exposure levels in Canadian underground mines. Because of the concern about the health impact of DPM/RCD on mine workers, North American agencies are in the process of establishing limits for these aerosols. So far, the Province of British Columbia is the only jurisdiction in North America to legislate the maximum exposure level of RCD in its underground mines, i.e. 1.5 mg/m3 interim level recommended by the Adhoc Diesel Committee. It has also recommended the use of the CANMET/ADHOC RCD sampling protocol.

Jan 1, 1993

WALTER N. CRAFTS,* Toronto, Canada (written discussion?).-During the forging of 9.2-in. shells -for the United States Army, it was noticed that better results were obtained in certain instances when test bars had been held sometime before pulling. An investigation, therefore, was made by our metallographer, Mr. F. M. Arnold, to determine the effect of seasoning. The forging consists of a single operation, piercing a solid cast blank. The test sections were cut from the walls by an oxyacetylene flame, one piece from the nose end and one from the base on the opposite side. The test pieces were not heat treated in any way and the tests and seasonings were carried on at normal atmospheric temperatures. The specifica-tions were as follows: Standard 2-in. test bar, 0.505 in. in diameter; elastic limit, over 19 long tons, or 42,500 lb.; ultimate stress, 39.6 to 49.1 long tons, or 87,500 to 110,000 lb. per sq. in.; elongation, over 13 per cent. As a preliminary test two heats were selected; BP555, which was tested and reported failed on elongation on Aug. 20; and B01771, which was tested and reported failed on Aug. 24. On Aug. 29, retests were cut and machined from the same shells and held till Sept. 3 (5 days) when they were pulled. Both sets of results are given below.

Jan 12, 1919

By Evan Jamieson

The conditions under which various iron(III) oxy-hydroxides phases precipitate from iron(III) chloride and sulfate solutions at ambient temperatures (<60°C) are reviewed. Many of these precipitates are slow settling and gelatinous but ultimately transform into other more stable or crystalline phases. The phase that forms depends upon the rate of precipitation and pH. A comparison has been made of the iron(III) oxides formed upon the neutralisation of various iron(III) solutions with caustic, slaked lime or slaked magnesia which provide different rates of neutralisation and slowly dissolving solids with localised high pH. Mössbauer spectra of ferrihydrites precipitated under these different conditions are compared and interpreted. Particular attention is paid to the settling rate and settled volume which is likely to relate to industrial thickener and filter performance. It is shown that in pure chloride solutions, poorly settling ferrihydrite is usually produced at 20oC regardless of the choice of base. However in sulfate solutions fast settling precipitates are produced using lime and magnesia but not with caustic. In mixed chloride/sulfate solutions, optimum settling rates occur when the molar ratio of [SO4]2to Fe3+ is about 1:1 and when the sulfate concentration is <0.20 M. It is proposed that ?dense amorphous basic iron sulfate? or well-ordered ferrihydrite is formed on slowly dissolving lime or magnesia surfaces. Implications for industrial liquors are considered.

Jan 1, 2003

By Harrison A. Schmitt

One of the great copper-producing areas of the world is comprised of five U. S. western states and northern Sonora, Mexico. The Southwest province of this area, covering southern Arizona, south- western New Mexico, and northern Sonora, produces some 55 pct of U. S. copper output and the equivalent of 15 pct of world production. In 1956 the area produced about 550,000 tons. Tucson is approximately the center of the oval- shaped province, which measures only 300 miles on its east-west axis and about 200 miles on its short axis. Northwest of the oval, and forming a tenuous connection with the Utah and Nevada copper fields, is an important operating mine, Bagdad, and also the now inactive United Verde. Along its north- south axis, running from Globe, through Tucson, to Nogales, ten moderate to major copper properties have been discovered or revived during the past 15 years, and five of these in only the past seven years. The latter five properties lie in an area 25 miles in diameter, centering 20 miles south of Tucson. In order of discovery, or revival, they are: Banner&apos;s Mineral Hill and Daisy; Cyprus et al&apos;s Pima; Duval&apos;s Esperanza; Asarco&apos;s East Pima (now called Mission mine) ; and Lewisohn&apos;s Peach. Total tonnage is estimated at about 250 million tons averaging some 0.90 pct Cu, but ultimate production may exceed this amount since some of the reserve is open ended.

Jan 6, 1959

"The earth is the Lord&apos;s and the fullness thereof." Science knows no national boundaries, knows no country. These views might be taken as premises for a discussion of the development of the mineral resources of the world. Yet how far man is removed from such broadminded ideals! In this day of jealousy and dread, of political machinations and statesmen&apos;s maneuverings, of rantings and crass ravings against fellow-beings, man&apos;s attitudes towards God&apos;s gifts are but the measure of the smallness of man. That the exploitation of mineral wealth should be for the common good, none will deny, but what is meant by "common"? Is it for the common good of The Pennsylvania State College, Pennsylvania, the United States of America, or the world? If man is big enough and honest enough to state categorically that by "common," as used in the context above, is meant that the utilization of the mineral wealth should be for the mutual benefit of all mankind, and that all concerned strive to see that such a viewpoint is executed, then there is brighter hope for the future. It is to be hoped that the world may have at least a few years or possibly a generation of peace. What can be done in these years to work towards the ultimate goal of human improvement? The work of statesmen in the drafting of international agreements and the easing of small frictions which appear between nations, as they

Jan 1, 1950

By Paul Torrey

THE Northwestern Pennsylvania Oil Producers Association and the United States Geological Survey have cooperated in conducting a pre-liminary study of the character of the flood waters, the relationship of changes in concentration of the salts dissolved in these waters to ultimate flood-oil production, and the original association of oil and water in the Bradford field. Bradford has long been recognized as a dry-sand field. As a matter of fact, there had been little information available on the oil-field waters of northern Pennsylvania until this investigation was undertaken. THE BRADFORD SAND Practically all of the oil produced in the Bradford field comes from one horizon, generally known as the Third, or Bradford, sand. Originally, it was believed that the Bradford sand was equivalent to the Third sand of Venango County, Pennsylvania and the name "Third" unfortunately still persists, although shortly after the discovery of the Bradford pool Carll1 determined that there was a stratigraphic interval of approximately ;000 ft. between the two horizons. The Bradford sand, although varying considerably in thickness and lithology within local areas, is persistent throughout the field. It is of marine origin and, upon both paleontologi-cal and stratigraphic evidence, is regarded as a basal member of the Chemung formation.

Jan 1, 1927

By M Castle, D Mendelawitz

The Marra Mamba iron ore in FortescueÆs Chichester Range project area occurs as a very flat dipping series of waste shale and iron ore beddings. These beddings vary from millimetre thickness to several metres. The ore material generally exhibits a moderate degree of competence when subjected to ultimate compressive strength (UCS) tests, normally failing at up to 60 Mpa. However, the strength of the beddings is markedly less when subjected to the tensile forces imposed by the cutting action of the surface miner. Two surface miners of differing age and sizes were tested over a period of almost three months. These machines produced a product that had not been subjected to dilution by blasting and of such a size that primary crushing is not required. The machines were able to cut all ferrous material presented to them with varying degrees of success. Material containing higher quantities of manganese were broken but caused catastrophic wearing of the picks. During the trial the volume of material produced by the two machines in various strength materials very closely matched the manufacturerÆs estimates. The major impact on costs per tonne related to the wear on bits, which in turn varied with the bit design and composition. Bit design and composition testing is continuing.

Jan 1, 2007

(Quality can be defined as that which is acceptable to the market and can be supplied with a predictable degree of uniformity and dependability at a low cost. The market for any mining product is downstream processing, whether it be an alumina refinery, a gold processing plant or a flotation plant. The cost of that downstream process is partly dependent on uniformity of its feed material both in physical and chemical terms. With more operations adopting procedures which require quality assurances in line with International Standards, from their raw material suppliers, miners must look to their grade control processes to provide uniformity and predicability.This is not a new concept. The mining industry has constantly been working with ahighly variable raw material supplied by Mother Nature, from whom we cannot demand quality assurances. Through the processes of exploration, resource and reserve definition, long and short term mine planning and day to day grade control an end product has been supplied which consistently meets our customers requirements, in an economic fashion. When any of these processes fail, then penalties are incurred which can range from increased mineral processing costs to loss of markets and in the ultimate case, failure of a mining operation.

Jan 1, 1992

By W. Belobraidich

Kennecott&apos;s Ray mine is located about 145 km (90 miles) north of Tucson in the Mineral Creek mining district of central Arizona. Mining in the district started in the late 1800&apos;s. The Ray mine itself was first mined by under- ground methods in 1911 and was changed to an open-pit operation in 1952. Mineralization is complex and includes sulfide, silicate, and native copper mineralization, as well as minor amounts of molybdenite. Sulfide ore, mined at Ray, is shipped by rail to Kennecott&apos;s concentrator and smelter at Hayden, 32 km (20 miies) away. Silicate ore, mostly chrysocolla, is processed near the mine in a vat leaching-electro- winning plant. The mine consists of two sulfide areas: (1) the West pit and the Central pit (the original Pearl Handle pit) and (2) a silicate area on the northeast perimeter of the Central pit. The pit now is over 304 m (1000 ft) deep and approximately 3048 m (10,000 ft) long. Roads within the ultimate pit are limited to a grade of 10%, while those outside the pit are limited to 8%. The mining equipment consists of 40 Wabco 1094 (120-st) haulage trucks [ranging from 109 to 227 t (120 to 250 st)], 12 electric shovels [ranging from 6 to 23 m (7 to 25 yd)], and 3 11-m (12-yd) Dart production loaders.

Jan 1, 1979

By Gordon King

This paper presents a case study of large diameter continuous flight auger (CFA) piles and drilled shafts utilized for foundation support of a series of heavily loaded cement plant structures at the Suwannee American Cement (SAC) Plant in Branford, Florida. The high loads and exacting total and differential settlement criteria when combined with a highly variable subsurface geology provided a challenging design scenario. Fully instrumented static pile load tests were performed to determine design parameters in the variable weathered limestone bedrock. Ultimate side friction values ranged from 2 to 8 tsf within the limestone, resulting in the requirement for CFA piles up to one meter (approximately 40 inches) in diameter and socket lengths of up to 40 feet. At several localized areas, the limestone bedrock was in excess of 60 feet below grade, requiring the use of cased drilled shafts to depths on the order of 80 to 90 feet. An integral part of the production pile installation was the use of instrumentation to monitor drilling and concreting parameters. Calibration of drill rates, torque and auger rotation with rock quality was performed to allow monitoring of the soil stratigraphy at each pile location. When combined with the results of the instrumented load testing, the monitoring of drilling parameters allowed confirmation that sufficient socket length was achieved within the quality of rock present at each and every pile location.

Jan 1, 2003

By B. Sergeant

Any study of the contentious subject of nationalization can ultimately be reduced to a sombre analysis of the simultaneous, and very different, interests of capital, labour, and government. Each of these interests attempts to maximize its objectives, subject to checks and balances provided, in an ideal system, by a country&apos;s executive government, legislature, and judiciary. Where even one of the three interests goes out of control, the consequences can be disastrous. The case histories show that when this occurs, the most common culprit is government, or its proxy, such as a dictator. At the other extreme, the case studies indicate that the optimum outcome occurs when capital, labour, and government are &apos;ring fenced&apos; from each other: each enjoys its rights, but is also subject to duties. &apos;Conflicts of interest&apos; between the three entities are ideally avoided to the maximum possible extent. The case studies include several salient instances from both the DRC (Gécamines, La Générale des Carrières et des Mines) and Zambia, along with Ghana and Chile. Further instances are examined in South Africa (gold), India (Coal of India), Brazil (Petrobras), Venezuela (Petróleos de Venezuela), Sweden (Luossavaara-Kiirunavaara Aktiebolag), Mauritania (Société Nationale Industrielle et Minière), Norway (Norsk Hydro), Botswana (Debswana), and Namibia (Namdeb). The article concludes broadly that South Africa&apos;s minerals sector is not ready for nationalization.

Jan 1, 2013