Search Documents

By D. M. Sloan

While surety capacity for the mining industry continues to shrink, States are demanding greater financial certainty for closure/post closure obligations. To combat these demands, larger mining companies are pursuing a Mining Surety Reinsurance Program that requires a significant up front capital contribution. This paper outlines an alter-native program for middle market mining organizations. The program utilizes a “Blended Finite Risk” environmental insurance solution with surety acting as the “front” in states where insurance is not an acceptable form of collateral. Marsh proposes creating separate programs for each State requiring surety. The reason for separate programs stems from each states’ different surety rules. Insurance companies typically require at least $5 million in future value remediation liabilities for finite risk programs. Since most middle market mining companies have obligations that fall below this threshold, the Blended Finite Risk Program contemplates combining several companies closure/post closure liabilities to accomplish the minimum amount required by the insurance company. Why use a Blended Finite Risk Program? One of the primary benefits is the financial assurance that funds will be available for planned remediation. For example, the financial assurance may be required by a government agency. The certainty may help facilitate a merger or acquisition. Additionally, the funds may be part of a CER-CLA PRP settlement. In all cases, the insurer providing coverage would be a secure independent 3rd party. A Blended Finite Risk Program also provides a long-term solution – up to 30 years and in some select cases longer. The benefit to a state or the BLM is the removal of financial uncertainty. An insurance company writing the policy would have an AA or AAA balance sheet. The hardening of surety markets coupled with the tightening of financial assurance requirements in many states have necessitated the posting of 100% collateral. This program substantially reduces these collateral requirements.

Jan 1, 2004

By Slavko Ostojic, V. G. Hill

This paper reviews various bauxite classification schemes with respect to the differences in texture, composition and geological associations of the deposits. It demonstrates that a techno-economic classification, based on: a) associated rock type - lateritic versus karstic, b) content of aluminum ore minerals - gibbsite, boehmite and diaspore, and c) gangue minerals (iron oxides etc.) has a geological basis with natural cut-off points for the bauxite types identified. Thus, this scheme is seen as applicable to bauxite resources. It also provides a basis for their rational exploitation taking into consideration the long-term interests of both the bauxite producing and consuming countries. Against this background, the industrial mineral or non-metallurgical grades of bauxite are seen as localised and relatively rare occurrences. Their consumption should, therefore, be aimed toward the specific (hence more remunerative) products as indicated by the bauxite characteristics.

Jan 1, 1984

By Robert Sutton, Milan Sjaus

Conveyor pulleys are an important and integral component of a conveyor. Conveyors work in sequence to make up conveyor systems. Each conveyor system is only as reliable as its crudest component. If the pulley fails, then the whole material handling system stops. So what is the effect of this downtime? What are the costs of repair? How much are we willing to pay to solve the problem? What should we spend to prevent an unscheduled shutdown? Do we use the technological improvements at our disposal or do we ignore them to satisfy immediate cost savings? This study will focus on the cost of pulleys relative to the total conveyor cost, the cost of downtime, the maintenance costs and the costs for resolution of the problem. Some philosophic and design concepts are injected for illustration and discussion.

Jan 1, 2000

By Cynthia S. A. Wallace, Joseph E. Crawford

The Culberson ore body is a bioepigenetic sulfur deposit located in the Delaware basin. Sulfur occurs in the Upper Permian Castile, Salado and Rustler Formations. Most of the ore body forms a subhorizontal layer within the Salado Formation. Abundant cave fill deposits of Rustler and younger lithologies occur within the Salado Formation and predate mineralization. The cave fill deposits provided porosity zones within the otherwise impermeable sulfate host rock and controlled sites of mineralization. A northeast trending fracture zone near the west edge of the ore body localized some deep mineralization and may have allowed migration of hydrocarbons from depth.

Jan 1, 1992

By John P. Norton

Microcystaline silica has been mined in Illinois from the Clear Creek formation since the turn of the century, especially in the area around Tamms in Alexander County, in the southernmost part of the state. Production of this silica, consumed mainly by the abrasives and coatings industries but also sought after for many filler/extender uses, has grown with the economy with several new applications overshadowing traditional markets in recent years. Such an important commodity was given the early attention of the Illinois State Geological Survey and a very complete report was issued in 1953 (Report of Investigations No. 166), authored by J. E. Lamar. The mining and processing of the silica ore has changed very little since the first reported production in 1906, although emphasis has been placed on the production of the finer sized grades to meet newer market requirements. Industrial Mineral Notes 40, published by the Illinois State Geological Survey in June 1970, describes a method by which a less than 1-micron fraction could be commercially produced from the readily available finest commercial grade presently being marketed (99% minus 10 microns). The finer grades exhibit to a lesser degree the reinforcement, high flatting efficiency, thickening and dry brightness properties associated with the synthetically produced silicas. It is expected that the extremely fine grades of microcrystaline silica will become accepted in the markets that now use a combination of precipitated silica and less expensive extender/filler minerals such as kaolin or calcium carbonate.

Jan 1, 1976

By A. McCombs

Previous models describing the aggregation of polymer-coated particles fail to take into account the fact that there are a limited number of sites onto which a polymer segment can adsorb, called "active" sites. Thus, the collision efficiency is a factor not only of the fractional surface coverage, but also of the number of active sites. In this study, a physical model of the flocculation system was devised in which the number of these sites could be varied, in order to study the effect on particle aggregation.

Jan 1, 1988

By Sammie D. Guy

This paper discusses the subject of "Improving Contracting Methods" from the owners point of view, particularly the public. An overview is given of the work of the U.S. National Committee on Tunneling Technology and some apparent results of the implementation of these recommendations or lack thereof. Selected recommendations that are not being implemented are discussed as to the the desirability and the possible impact of their implementation. Impediments to acceptance of the recommendations are identified and solutions proposed. The difference in the flexibility, attitudes and approaches of owners, public, quasi-public and private, toward improving contracting methods are discussed. Particular emphasis is given to the fact that the onus to improve is on the owner because they usually develop the contractual language or at least have the final decision on its content and are or should be an equal party to the contract during its administration.

Jan 1, 1983

By G. Jeffrey Taylor

The environment at the lunar surface is drastically different from the one we are used to on Earth. The Moon has one-sixth of Earth's gravity, virtually no atmosphere, a surface bathed in radiation and micrometeorites, large temperature gradients, low seismicity, and a dusty, rubbly surface. To successfully mine and process materials on the Moon and to mitigate degradation effects in the hostile lunar environment, these factors require new designs for equipment and development of new techniques and technologies.

Jan 1, 1990

By Steve Tadolini

Underground roof falls can have devastating effects on the safety of operations personnel, and equipment, and seriously impact production. Immediate steps are usually taken to danger off and secure the area while clean-up efforts are designed and implemented. A critical step, often overlooked due to production demand, is the determination of - why the roof fall occurred so that additional occurrences can be avoided in future developments or what measures can be taken to identify areas that have similar ?symptoms?? Forensic engineering includes the investigation of materials, products, structures or components that fail or do not operate/function as intended. The authors define forensics in ground control engineering as the study of evidence discovered while examining underground roof falls by applying expert observational techniques and established mining engineering principles to determine the probable cause, hypothesize solutions, and design engineering safeguards to prevent reoccurrences. Simply stated, the primary steps in the forensics of underground roof fall techniques are: ?Assess regional and local conditions prior to the event. ? Assess post-event conditions. ? Hypothesize plausible ways in which the pre-event conditions became the post-event conditions. ?Search for evidence that either denies or supports the various hypotheses. ?Apply engineering skill to relate the various facts and evidence into a cohesive scenario of how the event may have occurred. This paper details the proposed technique by utilizing a roof fall case study that required the examination of five primary factors: mine design parameters, excavation geology, method of excavation, method of support, and mining cycle times.

Jan 1, 2009

By Murray D. Lester

The relationship between bauxite and energy has two distinct aspects. On the one hand, since virtually all of the bauxite that is mined winds up as aluminum metal, the economic health and future of the bauxite industry and of the bauxite-producing countries depend on the continuing vigour and competitiveness of aluminum against alternative metals and materials. The price of aluminum is, in turn, particularly dependent on the price of energy. Hence, the need for bauxite is ultimately affected by the price of energy. The second aspect relates to location of the bauxite industry. There is no shortage of bauxite resources in the world. For various reasons, as we shall see, there is a growing tendency toward the integration of bauxite mining, bauxite refining and aluminum smelting in those countries that have the resources both of bauxite and of energy necessary to support the entire production chain. Thus, the availability of attractive energy supplies will increasingly favour development of bauxite mining: the traditional export of bauxite as a simple raw material is likely to diminish in relative terms. In short, both the amount of bauxite mined and where this mining will take place are related to energy considerations. Let us first have a brief look at the four basic activities that are involved in our integrated operations: A. The bauxite is mined and moved to an ore plant. This step does not require more than relatively modest amounts of energy normally associated with excavation, loading and shipping of any bulk material. We need about four or five tonnes of bauxite for every tonne of metal produced.

Jan 1, 1984

By Andrew Torok

Activated bleaching clays, so called because of their ability to remove color bodies from bleach fats and oils, are produced from clays of bentonitic origin. Activation is achieved by subjecting these clays to physical or chemical alteration to increase selective sorption capacities (1) . The future of activated bleaching clays depends upon the ability of producers to recognize the new areas of applications which are arising, and their skill in developing sophisticated active clays to meet new and stringent requirements. The major portion of activated bentonites are produced for decolorization of oils. New techniques of activation will improve these clays for broader spectrum use. General properties expected to result from present activation methods are: 1. Modification of hydrophobic-hydrophilic properties and increased available surface area in non-aqueous systems, thereby improving sorption capacity and ability to remove color bodies from oils. The following additional properties will be expected from future activated clays: 2. High purity of the active clay with interfering impurities totally removed. 3. Increased selective sorption capacity in aqueous systems. 4. Selective chemical reactivity, such as oxidation or hydrolysis. This property is required for removing

Jan 1, 1971

By R. Addison

Boom, boom, boom, boom. The staccato beat rings out across the bush; the stamps are at work - slowly pulverizing gold-bearing ore for a patient, grizzled prospector. This is the State Battery near Marvel Loch - a tiny (capacity: 25 ton/day) gold plant operated by the Western Australian government. It is one of many such plants located in remote corners of Western Australia and the Northern Territory - miniature custom mills operated for the benefit of prospectors and small mine operators. These State Batteries, so called because they are operated by state governments and because the principal item of machinery in the plants are stamp batteries, are fascinating anachronisms: throwbacks to times long past, to a century ago, to the hard and heady existence of gold rush days.

Jan 1, 1986

By J. N. Economopoulos

The mining industry is becoming increasingly aware of environmental issues and has made big forward steps in the field of environmental management. Legislation, social pressure and competition introduced changes in the industry?s policies and practices in order to conform to the new standards of environmental performance. The paper addresses the need for an integrated and systematic approach to the issues of environmental management within the mining industry.

Jan 1, 2002

By R. P. Upadhyay

The Deserado Mine, located in northwest Colorado, is an underground coal mine designed to produce 1.225 million tons (1.35 million short tons) of clean coal per year for the Bonanza Plant located in northeastern Utah. Coal is transported to the power plant via a 61 kilometer (38 mile) captive railroad. Most of the surface facilities and the stationary underground equipment is controlled and continuously monitored by the computers located at the surface control room. In addition to system control, the computer also continuously monitors vital environmental conditions using sensors located at various critical locations underground. The system's advantages are increased mine productivity and safety.

Jan 1, 1988

This chapter looks at the development and use of the operating budget. This is management's plan of action in the short term, usually one year. The operating budget includes all expensed production costs (i.e., all costs reported as cost of goods sold) but does not include expenditures on capital equipment, which are usually justified using discounted cash flow techniques.

Jan 1, 1999

By Robert L. Bates

United States production of the industrial minerals, ahead of that of the metals since 1946, has shown a steady and rapid growth. By 1963, their value was more than twice that of the metals. Yet papers on the metallic ores continue to dominate the meetings of the Society of Economic Geologists and constitute nearly nine-tenths of the lead papers in Economic Geology. Most of the geological communication that does take place concerning the industrial minerals deals with high-value special-purpose minerals, which are comparable to the metallic ores in geologic complexity. The large-bulk rock products, which are growing fastest in production value, are characterized by relatively simple geology and by thousands of small producing firms, many of which do little or no geological work. The need for geological advice by this very large segment of the industry is bound to increase. In the meantime, a plea is made for more geological communication among those concerned with the industrial minerals of all varieties.

Jan 1, 1966

By James D. Piper

In the summer of 1957,9 the University of California sponsored a World Conference on Prestressed Concrete in San Francisco to which were invited a number of Soviet engineers. While attending the conference, these engineers in turn asked the University to form a delegation of American engineers to visit the Soviet Union the following year for the purpose of studying Soviet advances in concrete technology. A six man delegation was formed, and the dates of the Russian tour fixed for May 10th through May 21st, 1958. Before arriving in the Soviet Union, the American Delegation attended the Third International Congress on Prestressed Concrete in Berlin. While there, we noticed that the delegation from the U. S. S. R. used displays and showed motion pictures of many construction projects which we later were shown in Moscow. Our delegation left East Berlin by Russian aircraft on May 11th, and arrived in Moscow that afternoon. We were met by our Russian engineer hosts from The Academy of Construction' and Architecture who made all subsequent arrangements for our itinerary. This Academy has no counterpart in the United States. It. does 40 per cent of all engineering-and scientific work in the building construction field and coordinates 60 per cent of that done by other Soviet agencies. Due to the prestige of the Academy in Russian affairs, our delegation was able to obtain a surprisingly broad picture of construction activities in Moscow and Leningrad in just ten days time

Jan 1, 1960

By Alfredo Dammert

The paper presents the results of a model built at the World Bank in order to analyze the aluminum industry. Bauxite demand for the year 2000 is estimated as a function of alumina refineries' requirements and of non-metal uses for bauxite. Bauxite supply by countries or regions depends on economic factors such as investment costs, operating and transportation costs, as well as on tariffs and levies. Various scenarios are considered as a result of varying the assumptions of the model.

Jan 1, 1984

By D. C. White

The Vulture Mine near Wickenburg, Arizona was a major gold producer from 1863 to 1942, having yielded about 11,000 kg Au and 8,000 kg Ag. Gold occurs as coarse native metal and electrum in quartz veins and also finely disseminated within a quartz monzonite sill and its silicified wall rock. The sill is semi-conformable within a Proterozoic volcaniclastic-dominated sequence all dipping north about 35°. Early mining focused on the vein-hosted gold particularly in the immediate hanging wall and footwall of the sill. Later efforts included some open-pitting of the outcropping sill and adjacent altered and mineralized rock. Two sets of post-mineral faults have complicated the orebody geometry.

Jan 1, 1988

By Lester F. Sanford

Located in the Santa Cruz Mountains eight miles north of the City of Santa Cruz and inland from the coast, lies a typical beach sand consisting of quartz and feldspar grains of the Santa Harguerita formation of the middle tertiary age, Reserves of over twenty-five million tons of this sand form the deposit presently being harvested by Pacific Cement & Aggregates, a Division of Lone Star Cement Corporation. The deposit ranges from 350 to 700 feet above sea level and varies from two percent passing a 200 mesh screen to ten percent retained on a ¼ inch screen (see Figure '#l) In 1929 the first sand plant went into operation at this site. It was replaced by a new plant in 1937. This plant continued operation until the middle of 1965 when replaced by the modern plant described in this paper.

Jan 1, 1967