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By D. V. Bush

There has been a great deal of evaluation and discussion on the economics of semi- autogenous grinding versus conventional grinding circuits. This paper will not discuss the merits of one system over the other, but rather will discuss the Henderson Mill's approach toward achieving the most economical milling conditions in its existing SAG mills.

Jan 1, 1985

By Harvey S. Mudd

AMONG the highly skilled craftsmen of the Renaissance were those who worked with ores and metals. The author of this book, Vannoccio Biringuccio, was a master craftsman in the practices of smelting and of metalworking. Contrary to the customs of a trade, Biringuccio was moved to impart his knowledge to all and thus he has given us the earliest hand- book on metallurgy-in fact, the first printed book dealing with the applied metal arts and the processes of ore reduction. We should remind ourselves that metallurgy is an ancient art and then it fair1y may be said that Biringuccio sought to describe the techniques that had been in course of development since the Bronze Age of western civilization. Whether Biringuccio was a man of learning or a scholar according to the standards of his time we do not know, but today we recognize him as a man of science who gave his wisdom to succeeding generations. It was not until the coming of the Power Age at the end of the eighteenth century that progress was resumed in the science of which he wrote more than two hundred years before. Little is known of Biringuccio's training in his native Siena. It can be surmised that there, as in Florence, where his contemporary Benvenuto Cellini lived, he received his training in the craftsman shops where the industrial arts were taught and flourished alongside the fine arts. Perhaps he and Cellini were acquainted, although there is no mention of Biringuccio in Cellini's autobiography-an omission that Cellini's vast egotism makes understandable. He was the great artist, and Biringuccio was a practical, studious, unromantic figure with no favors to dispense. In the April 1940 issue of Mining and Metallurgy Dr. Smith describes Biringuccio's book under the title of "A Neglected Italian Metallurgical Classic." The article, revised and extended, forms the basis of the introduction to the present volume, and I urge all who take up Pirotechnia to read what Dr. Smith has written in the Introduction. Biringuccio's work is a classic and in its translation Dr. Smith and Dr. Gnudi have brought to bear the high degree of scholarship that it deserves. Dr. Gnudi made the translation at Dr. Smith's request and it was then refined "in the fire" of his scientific knowledge of the subject. The result is a book which the Institute is proud to place before its members and which the Memorial Fund Committee considers it a privilege to publish.

Jan 1, 1942

By George S. Rice

Those who for the first time see, at a mine, a great hole caused by subsidence; or, going underground, see an extensive fall of roof or hanging wall are apt to regard such an occurrence as an accident and not a normal condition of exhaustive mining. Moreover, the public is inclined to believe that a cave or subsidence of the surface is the result of carelcssness in mining or the rapacity of the mine operators in "robbing pillars," a tern too loosely used in descriptions of coal mining. This belief is fostered by the common-law requirement that an owner of the surface or of surface improvements is entitled to full support of the surface. Court decisions have upheld this law even when that owner has sold or leased the underlying mineral, unless a clause in the sale or lease contract exempts the mining company from paying the owner of the surface for damages that may result from mining. Another reason for this belief is the earlier practice (which is still extensively followed in this country) of leaving all coal pillars unmined, except as they have been thinned by so-called robbing; by not extracting the pillars, the surface may be supported by them for years, perhaps for generations. Inasmuch as the practice of leaving permanently in the mines from one-third to one-half of the mineral is wrong, with respect to conservation of a national resource, it behooves the mining engineers to assemble data and disseminate information on the subject, pointing out that subsidence must follow complete extraction, unless expensive methods of back-filling are employed, such as are used in Germany and France. These methods inevitably increase the cost of mining and the price of the mineral produced. It is popular to speak of "waste in mining" without a realization that much so-called wasting is unavoidable unless subsidence is accepted and provision made therefor where the surface is valuable, or else the only present known alternative of hydraulically placing sand or crushed stone filling in the excavations, at an increased cost of the mineral product to the consumer.

Jan 1, 1923

By George S. Rice

Those who for the first time see, at a mine, a great hole caused by subsidence; or, going underground, see an extensive fall of roof or hanging wall are apt to regard such an occurrence as an accident and not a normal condition of exhaustive mining. Moreover, the public is inclined to believe that a cave or subsidence of the surface is the result of carelcssness in mining or the rapacity of the mine operators in "robbing pillars," a tern too loosely used in descriptions of coal mining. This belief is fostered by the common-law requirement that an owner of the surface or of surface improvements is entitled to full support of the surface. Court decisions have upheld this law even when that owner has sold or leased the underlying mineral, unless a clause in the sale or lease contract exempts the mining company from paying the owner of the surface for damages that may result from mining. Another reason for this belief is the earlier practice (which is still extensively followed in this country) of leaving all coal pillars unmined, except as they have been thinned by so-called robbing; by not extracting the pillars, the surface may be supported by them for years, perhaps for generations. Inasmuch as the practice of leaving permanently in the mines from one-third to one-half of the mineral is wrong, with respect to conservation of a national resource, it behooves the mining engineers to assemble data and disseminate information on the subject, pointing out that subsidence must follow complete extraction, unless expensive methods of back-filling are employed, such as are used in Germany and France. These methods inevitably increase the cost of mining and the price of the mineral produced. It is popular to speak of "waste in mining" without a realization that much so-called wasting is unavoidable unless subsidence is accepted and provision made therefor where the surface is valuable, or else the only present known alternative of hydraulically placing sand or crushed stone filling in the excavations, at an increased cost of the mineral product to the consumer.

Jan 1, 1923

By T. T. Chen

This mineralogical study is based on samples from typical "wet" nickel laterites of humid tropical to sub-tropical regions. An in-situ nickel laterite sample from Goro and a transported laterite sample from Plaine des Lacs, New Caledonia, are predominantly limonitic. Two-thirds of the particles in the Goro sample are <10 um in size; they consist of skeletal goethite and serpentine, as well as minor amounts of talc, gibbsite, chlorite, quartz and clay minerals. The coarser grains are mainly Cr-spinel, serpentine, gibbsite and Mn oxide. Nickel occurs mainly in goethite, serpentine and Mn oxide; cobalt occurs in goethite and Mn oxide. The Plaine des Lacs sample is finer-grained and contains more Al and CO3, but less Mg and Si than the Goro material. The sample contains more kaolinite, chlorite, siderite and feldspar, but less serpentine and gibbsite than the Goro material. Nickel is detected mainly in goethite, serpentine, Fe-Mg silicate and Fe-Mn oxide. The Indonesian ore from Sorowako, as sampled from the reduction kiln feed containing some reverts, is predominantly saprolitic, with apparent particle sizes ranging from <100 um to > 1 cm. The sample of reduction kiln feed is rich in Mg silicates, Mg-Fe silicates and goethite, and exhibits complex alteration textures. The nickel contents vary from particle to particle. Nickel is present mainly in serpentine, olivine, chlorite and amphibole, and in subordinate amounts in goethite and Mn oxide. Cobalt is detected in the Mn oxide. Keywords: Nickel Laterite; Mineralogy; Nickel Carriers; Goro, New Caledonia; Plaine des Lacs, New Caledonia; PT Inco., Sorowaki, Indonesia

Jan 1, 2004

By I. Iwasaki

There are many reasons why the US mineral and primary metals industry is in its present state. Undoubtedly, a flood of imported goods in all sectors is playing a major role in the plight of our raw materials industry. Domestic industry is becoming increasingly aware of the importance of its international competitiveness. And we are beginning to wonder what is happening to our technological edge. A number of factors affect the international competitiveness. Engineers cannot do much about some of these factors - labor costs, tax policy, government relations, interest rates, dollar strength, and labor-management relations. Something can be done about technology, however. Some say technology is so easily transferable today. But I would like to believe that we have the ability to apply it better than others. Not too many years ago, "made in Japan" meant cheap and shoddy products. Today, Japan has completely changed its image. The US is beginning to feel the threat from Japan&apos;s low-cost, defect-free products with dependable delivery. With worldwide recession and the strength of the dollar, we were shocked at the sudden weakness that developed in America&apos;s industries, not only in the international market, but domestically as well. What went wrong and what can we do about it? Senior executives from 300 large American manufacturing companies were surveyed. These executives believe US companies must: • invest in more efficient plants and equipment (27%); • invest in more research and development (23%); • improve the quality of service to customers (23%); and • adopt more aggressive marketing tactics and strategies (14%). Are we not doing enough research? The US has nearly four times as many people engaged in research and spends four times as much for research as Japan (Fig. 1). There is little doubt about the excellence of the US performance in basic science as indicated by the number of Nobel prize recipients. Japan has produced only four winners since World War II. Look at technology trade of five countries (Fig. 2). Again, US performance has been remarkable. An interesting observation here, is that the United Kingdom, another country with economic woes, is also in the black, West Germany and Japan, both with trade surpluses, are net technology importers. It is apparent that the US&apos; performance in the commercialization of new knowledge is much more in question. Japan had $50 billion of trade surpluses with the US last year, which led to some friction between Washington, DC and Tokyo. Comparing the technology trade of Japan and the US in more detail, Japan imports disproportionately large amounts of technology from the US and Europe. This data is rather old, 1978, but the general trend is not too different even today. It is generally believed that scientific research leads to innovative technology, then to economic payoff. But, after seeing the current technological challenge by Japan, we are forced to change this traditional view. Investment in research may eventually lead to economic payoff, but not directly. There is a middle ground between new knowledge and its commercialization. This is an area where the Japanese have been successful. Until the 1970s, many western companies licensed patents to Japan for quick profits. But, in recent years, these companies have become more discrete about the terms of technological transfer. As a result, a number of scientists and engineers are expressing deep concern over the future of technological developments in Japan. A survey was conducted on 450 research managers of private industries in Japan on how they viewed the level of breakthroughtype original research in Japan as

Jan 6, 1986

Both drilling and production of oil decreased in Rumania during 1935. The drilling totaled 1,042,041 ft. and production 61,973,938 bhl., being a decrease of 8.5 and 1.6 per cent, respectively. Wells completed during the year totaled 198, of which 168 were oil wells, compared with 238 and 215, respectively, of 1934. No important discovery was made during the year. The only new field found was Valea Calugareasca, where the Credit Minier completed a small well on the westward plunge of the anticline. Drilling higher on the structure will probably prove the field to be of greater importance than the results of the discovery well indicate. The only other developments of importance were the extension of the Bucsani field, the opening up of a new area on the northeast of the salt at Moreni by Credit Minier and a minor extension of the West Gura Ocnitei field. At Calinesti, on the cast extension of the Moreni field, exploration work continued and a gas well was completed, but oil in commercial quantities is yet to be found.

Jan 1, 1936

Both drilling and production of oil decreased in Rumania during 1935. The drilling totaled 1,042,041 ft. and production 61,973,938 bhl., being a decrease of 8.5 and 1.6 per cent, respectively. Wells completed during the year totaled 198, of which 168 were oil wells, compared with 238 and 215, respectively, of 1934. No important discovery was made during the year. The only new field found was Valea Calugareasca, where the Credit Minier completed a small well on the westward plunge of the anticline. Drilling higher on the structure will probably prove the field to be of greater importance than the results of the discovery well indicate. The only other developments of importance were the extension of the Bucsani field, the opening up of a new area on the northeast of the salt at Moreni by Credit Minier and a minor extension of the West Gura Ocnitei field. At Calinesti, on the cast extension of the Moreni field, exploration work continued and a gas well was completed, but oil in commercial quantities is yet to be found.

Jan 1, 1936

By Stephen P. Winkelmann

The expansion of gold production in Nevada&apos;s Carlin Trend over the last few years has been staggering. To increase gold production while minimizing capital requirements and providing for the safe and efficient mining and processing of ores has required a tremendous effort by the mine engineering group at Newmont Gold. Organizational changes were implemented by the company to effectively deal with a full range of engineering problems. Specially developed computer software and its applications will be explained in this article as well as improvements in the techniques used in converting geologic resources into reserves. Scheduling procedures for the mining of multiple pits to feed multiple processing facilities will likewise be presented. Ore control procedures and current mine engineering practices are discussed. Growth at Newmont Gold Expansion of production levels at Newmont Gold Co. was brought about primarily by the economic incentive to exploit increased reserves. From 1987 to 1989, mined production increased by 260%, gold production by 238%, and manpower by 166% (Table 1). These increases came quickly and demanded

Jan 1, 1990

By Gerard A. Flierman

INTRODUCTION There is a lot of discussion about the relative merits of sinter and pellets as components of a BF-burden. Many people claim that sinter is to be preferred and that the percentage of pellets in the burden must be restricted to 20%. During BF-trials in IJmuiden various amounts of pellets having various basicities were tried. It was concluded that there were no significant differences in furnace performance. Consequently the choice between sinter and pellets must be based on the local manufacturing costs (1). Table 1 gives a summary of the pellet experience in IJmuiden. [ ] Because the BF-trials were relatively short, a survey of published BF-operating data has been undertaken to investigate if differences between a sinter and pellet based BF- practice could be found. The comparison of BF-operating results has been restricted to coke rate and productivity.

Jan 1, 1977

By J. W. Adams

Measurements of surface magnetic field noise were made at various locations over the Geneva Coal Mine near Price, Utah, on June 12, 1973. The locations selected were on the surface over emergency locator beacons underground at depths between 3S0 meters (1150 ft.) and 488 meters (1600 ft.). The surface terrain where these measurements were made was mountainous, and access was difficult. There were no power lines within several miles, and the weather was clear; therefore, the magnetic noise levels were about as low as will normally occur. Results of measurements of distant sferics indicate rather sharp cutoff frequencies below which broadband, impulsive noise is attenuated. The mechanism of propagation for this noise above the daytime cutoff frequency of 3500 Hz and the nighttime cutoff frequency of 1700 Hz is deduced to be a waveguide formed by the D or F layers of ionosphere as an upper plane and the earth as a lower plane.

Jan 1, 1974

By John P. Bernardi, Ralph B. Hall

Past and present phosphate production in the central Florida phosphate district has been predominantly from the unique Bone Valley formation. As these lucrative reserves are depleted, production will shift to the Hawthorn formation in all areas, but particularly so within the southern extension, where vast potential reserves of low grade phosphates exist. Use of existing plants can be extended for some years by mining deeper into the underlying Hawthorn formation, and by mining previously ignored peripheral areas if erratic combinations of the two formations. Hawthorn Production, as compared to the Bone valley, will be characterized by lower grade; lower tonnage yield, lower pebble percent of product, higher mining ratios, higher slimes (- 150 mesh) content, and more complex mining and beneficiation problems. Geological control and more sophisticated operational procedure; will become increasingly more important as the lower quality reserves replace Bone Valley production.

Jan 1, 1981

By Jeffrey A. Gebhard

As part of the design and construction of the new St. Anthony Falls I-35W Bridge, a full-scale load test was conducted on a 6 1/2-foot diameter drilled shaft in the St. Peter Sandstone. This load test helped identify shaft-rock interaction properties, including end bearing and multiple zones of differing shaft resistance for design of the drilled shafts beneath the three piers adjacent the river. The load test was designed by Load Test, Inc., Braun Intertec and the design team of Figg Bridge Engineers/TKDA and constructed by Design Build Consortium of Flatiron/Manson. Oversight was provided by the Minnesota Department of Transportation. Based on these test results, the drilled shafts supporting the St. Anthony Falls I-35W Bridge were designed to reduce risk and maximize economy for the people of the State of Minnesota.

Jan 1, 2009

Jan 1, 1925

By R. A. Pindred, M. P. Lam

Cyanide is a conventional lixiviant for gold extraction but its&apos; toxicity is a major concern for the environmentalist. There are many alternative non-cyanide lixiviants, such as thiourea, thiosulphate, chlorine and hypochlorite etc., which may reduce environmental sensitivity. This paper will discuss the leaching characteristics of gold in hypochlorite leaching solutions. The dissolution of gold in a hypochlorite solution not only depends on the concentration of the hypochlorite but also on other variables, such as hydrochloric acid, sodium chloride and temperature. The dissolution rate of gold in hypochlorite solution is much faster than other lixiviants. Due to the interference of impurities, gold extraction from an ore under ambient conditions requires large quantities of reagents. However, refractory gold ores may be successfully pressure oxidized in an autoclave at reasonably low reagent levels. Gold extraction to the pressure oxidation leach solution is rapid and complete in one stage, thus eliminating the need for further cyanidation.

Jan 1, 1990

This paper covers only the energy uses of natural resources and does not deal with non- energy uses, which in 1975 were of the order of 10 per cent of the total consumption of energy resources. The United Nations `J&apos; Series of Statistics ex- presses each of the various forms of energy in terms of its coal equivalent in metric tonnes and this basis is followed in this paper. One tonne of black coal (referred to as tce) has been taken as the equivalent of the following. 29 X 109 joules or 27.5 X 106 Btu 0.68 tonnes or 4.8 barrels of crude oil 750 cubic metres or 26.5 X 103 cubic feet of natural gas 1 ò5 to 3.3 tonnes of peat or lignite (world average 2.54; Victorian brown coal 3 0) 8055 kWh (at 3.6 X 106 joules or 3412 Btu per kWh at 100% efficiency) 2660 kWh at 33% efficiency of generation 50 grams of uranium present in natural uranium reactors (see note later under nuclear energy) 0.8 grams natural uranium in breeder reactors Nuclear and hydro electricity are expressed as the coal equivalent required to produce, at 33 per cent efficiency, the same amount of electricity. In other words, electricity produced by these sources is converted to its coal equivalent at the rate of 2660 kWh = 1 tonne coal.

Jan 1, 1978

Adsorption isotherms, zeta potential and coagulation techniques have been used to exa- mine the mechanism of metal activation on SiO2 and ZnS surfaces. The importance of surface nucleation or precipitation of metal hydroxide coatings is&apos;established and identified-by characteristic charge reversal patterns. The significance of surface coatings in sulphide and non-sulphide flotation is discussed.

Jan 1, 1973

By Frederico Muylaert Margem, Jarbas Bravo Neto, Sergio Neves Monteiro

"The mechanical behavior and the fracture characteristics of composites with DGEBA/TETA epoxy matrix reinforced with up to 40% in volume of continuous and thinner ramie fibers were evaluated by tensile tests. Specimens with selected thin fibers aligned along the tensile axis were room temperature tested to rupture. The fracture surface was analyzed by scanning electron microscopy. The results showed significant increase in both the ultimate tensile strength and the elastic modulus. The fracture analysis indicated the possible mechanism for the fiber/matrix interaction, which could be responsible for the composite performance.IntroductionThe fiber reinforced polymer composite emerged in the middle of last century as a versatile engineering material for applications requiring mechanical resistance in association with lightness. Its most commonly used example is ""fiberglass'', i.e., a thermoset polymer matrix composite reinforced with glass fiber. Indeed, ""fiberglass"" has a specific strength of the order of 500 MPa.cm3/g, which is the double of the strongest steels like the maraging. This motivated, at earlier times, ""fiberglass"" to replace many conventional materials including wood and natural fiber composites. Today, ""fiberglass"" has a wide range of uses from aerospace systems and appliances to sport and leisure components. However, its fabrication as well as those of any synthetic fiber such as carbon and aramid composites, requires a relatively large amount of energy. Presently, a growing concern exists regarding the consequences to the environmental by gases like C02 associated with both the energy consumption and the processing of synthetic fibers and their composites. These gases are well known responsible for global warming [1]."

Jan 1, 2011

By D. P. Plute

The mechanization of the materials management function must contribute to the overall goal of optimization of profits. A computerized system contributes to the profitability of the company by saving more than it costs to operate. Design and implementation of the sys- tem must respond to the needs of users, the operating environment of the property, and must support the objectives of materials management. Three basic functions interact within the scope of materials management. They are inventory control, purchasing, and warehousing which have the following objectives: 1) Inventory control-to request materials in a timely manner and in quantities that provide the best level of support to users at the lowest cost. 2) Purchasing-to purchase requested materials and services at the required time and at the lowest cost. 3) Warehousing-to efficiently receive, store, and issue materials and to prepare accurate transaction documents for the activities. The development of the mechanized materials management system will require a plan and objective analysis by management and system users of system requirements. A typical plan would include: 1) System Design Objectives-the development of objectives that support mechanization of the materials management function. 2) System Characteristics and Concepts- the development of key system concepts and characteristics, which identify the needs of materials management. 3) System Inventory Item Classification- development and assignment of inventory category codes to inventory items. 4) System Order Decision Rules-the development of decision rules and forecasting techniques to minimize the inventory investment and to provide acceptable support levels. 5) System Report Structure-the development of a report structure to support the goals and objectives of materials management. 6) System Report Design-the development and design of reports for effective utilization of the mechanized system.

Jan 1, 1979

By B. W. Madsen

Bureau of Mines research to recover arsenic from mining industry waste material and process streams is reported. Batch and column approaches were investigated for adsorbing arsenic from acid leach solutions and ion-exchange eluate solutions with hydrated titanium dioxide granules. A method for producing hydrated titanium dioxide granules was devised to provide material suitable for use in a packed adsorption tower. Selective adsorption of arsenic from acidic leach solutions was achieved. The loading capacity of arsenic on the granules was 14 wt-pct when synthetic solutions were used, but lower when actual leach solutions were used. Other elements in the leach solution were Zn, Cd, and In. The granules were used in an attempt to lower the arsenic content in a solution containing 0.95 g/l W and 0.027 g/l As from a process devised by the Bureau of Mines to treat Searles Lake brine. The arsenic content was lowered to less than 0.001 g/l, but unacceptable amounts of tungsten also were adsorbed by the granules. Adsorbed tungsten was partially stripped with pH 11.5 NaOH, and both tungsten and arsenic were completely stripped with 5M NaOH solution. Repeated loading and stripping of the granules had no effect on the loading capacity for arsenic.

Jan 1, 1983