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By D. Harrington

Approximately 6,000 coal mines are operated in the United States. All of them have in some degree the elements that are likely to contribute to an explosion, hence it is surprising that explosion disasters are not more frequent and that many mines have been operated for years and finally worked out and abandoned without experiencing an explosion. The absence of coal-mine explosions does not always indicate that effective efforts have been made to prevent them but rather that the nine has been fortunate in that the combination of circumstances necessary to cause an explosion has not existed. In view of present knowledge of the methods of preventing explosions, disasters are inexcusable and discredit the mining industry. The methods of preventing mine explosions are known to experienced, well-informed persons engaged in coal mining, yet despite this knowledge far to many coal-mine operators continue to use practices and methods that they should know have resulted in numerous explosions. Moreover, many mine workers persist in following past procedure irrespective of consequences and in breaking safety rules or indulging in practices almost certain eventually to result in disaster. Continued failure to apply known common-sense methods of accident and explosion prevention unquestionably will cell for ultimate enforcement of law.

Jan 1, 1940

By J. P. Caulfield

THE Hudson Bay Mining and Smelting Company's underground mine at Flin Flon, Manitoba, has in the past been serviced by two working shafts-the North Main shaft, and the No. 3 shaft. The North Main shaft is used to hoist the total production from under-ground, and handles the greater part of the mine supplies and crews. The shaft is five-compartment design, rectangular in cross-section, and is equipped entirely with steel shaft sets from the surface to the finished depth of 2,210 feet. Hoisting equipment in the surface plant will not permit the North Main shaft to be extended below its present finished depth. The No. 3 shaft, located approximately 2,300 feet from the North Main shaft, is used primarily as a ventilation shaft, and for hoisting lower-level development waste to the 390 level, where this material is used as mine fill. The No. 3 shaft is of standard rectangular design, timbered with 8-in. by 8-in. creosoted fir sets, hung on 6-foot centres. From the surface to the 1,430 level, the No. 3 shaft consists of three 5 ft. by 5 ft. compartments, and below this level to the completed depth of 2,300 feet, the shaft is increased to four compartments. To service the mine and to expedite development below the 2,210 level, a one and one-half compartment winze was sunk from the 2,210 level to a depth of 766 feet, or approxima tel y the 3,000 level.

Jan 1, 1941

By Alvin Kaufman

Geothermal plants are competitive with conventional units. A geothermal plant can produce electric energy for 6.70 mills per kwhr, compared with 6.96 mills for coal, 6.74 mills for oil, and 7.04 mills for gas. These costs include fixed and variable charges. Potential for geothermal power exists in the Western United States, Alaska, and possibly Hawaii. Assuming that the current downward trend in cost per kilowatt of coal will cease and that the relative cost of gas and oil, already trending upward, may rise considerably more, geothermal energy will be utilized where available, in producing electric energy. It will be used in California first because it is directly competitive with gas-and oil-fired installations there. A long-term appraisal is difficult because little is known about the sources of geothermal power and the electric generating capacity which the steam fields will support. However, a market for geothermal steam-generated electricity exists within the Western States.

Jan 1, 1964

By Peter C. Badgley

Three tectonic provinces within the Cordilleran System, are analyzed in terms of tectonic framework. (1) Precambrian terrain of North-Central Colorado; (2) The Pacific Northwest; and (3) The San Andreas-Garlock fault system and associated features. In each case a close relation- ship is seen to exist between: (I) Arcuate mountain development; (2) Precambrian basement fabric; (3) Major fault patterns; and (4) Major mineral occurrences. The arcuate trends developed when the basement was still mobile. Later competent deformation rejuvenated pre-existing lines of weakness. Because of the pre-existing arcuate framework, the rejuvenated faults frequently act as conjugate shears (strike-slip faults) flanking the old arcs. The conjugate shears intersect to form wedge- shaped plates. When such plates move forward along boundary strike-slip faults in response to post basement orogenic forces, new secondary fracture systems are generated in the country rock flanking the advancing wedge. The apex regions of the wedges are particularly favorable for detailed exploration.

Jan 1, 1959

By C. M. Bristow

The mineral kaolinite is one of the commonest minerals in the uppermost 10 m of the continental crust; ranking in abundance alongside minerals like quartz, mica, feldspar and calcite. Only very exceptionally does it possess all the necessary properties needed to make it worth commercially exploiting. The terms 'Kaolin' and 'Kaolinite' are derived from a locality known as 'Kau-ling', in Jiangxi Province, Peoples Republic of China; where samples of a white clay used by the Chinese to make porcelain were first obtained by European missionaries and explorers in the eighteenth century.

Jan 1, 1986

By Hasan Sevim

This paper summarizes recent developments in modeling of underground coal slurry haulage networks for determination of optimum design and operating parameters. The model presented here is based on a stochastic dynamic programming formulation, applicable in any typical room-and-pillar and/or longwall mining configuration commonly practiced in the United States. The formulation and the structure of the model is general enough to handle design problems involving more than one face and mining method. Given the stochastic operating characteristics and a system layout, the model can be used to determine the equipment configuration and operating regimes that minimize the overall unit cost of coal haulage.

Jan 1, 1983

By Alvin Kaufman

Geothermal plants are competitive with conventional units. A geothermal plant can produce electric energy for 6.70 mills per kwhr, compared with 6.96 mills for coal, 6.74 mills for oil, and 7.04 mills for gas. These costs include fixed and variable charges. Potential for geothermal power exists in the Western United States, Alaska, and possibly Hawaii. Assuming that the current downward trend in cost per kilowatt of coal will cease and that the relative cost of gas and oil, already trending upward, may rise considerably more, geothermal energy will be utilized where available, in producing electric energy. It will be used in California first because it is directly competitive with gas-and oil-fired installations there. A long-term appraisal is difficult because little is known about the sources of geothermal power and the electric generating capacity which the steam fields will support. However, a market for geothermal steam-generated electricity exists within the Western States.

Jan 1, 1964

By T. E. Gray

This report describes the preparation characteristics of the significant coalbeds in Harrison County, W. Va. It is one in a series of Federal Bureau of Mines reports planned to determine coals suitable for the production of metallurgical coke, either as mined or after beneficiation. Over 6.5 million tons of coal was produced in Harrison County, W. Va., in 1958, of which over 3.7 million tons was cleaned mechanically in seven preparation plants. All of the coal cleaned was from the Pittsburgh bed. It has been estimated that more than 1,816 million tons of coal remains in the county in beds 12 inches or more thick. The Pittsburgh and Redstone beds were selected by the Bureau for a study based on current production rates and estimated minable reserves. Sample locations were selected following a study of the literature, conferences with mining engineers and mining company officials in the field, and examination of the available sites. Six samples were collected from the Pittsburgh bed, and three samples came from the Redstone bed, Float-and-sink tests of the samples collected from the Pittsburgh and Redstone beds showed that neither coal could be upgraded to a metallurgical fuel under the standards set up for this study, even after intensive preparation. Finer crushing of the samples moderately increased the yields and slightly reduced both the ash and the sulfur contents in the 1.30-specific-gravity float fractions. Finer crushing slightly decreased the yields in the 1.58-specific-gravity float fractions, whereas it reduced the sulfur content 0.11 percent for the Redstone sample and 0.46 for the Pittsburgh sample.

Jan 1, 1961

By W. M. Bangert, F. S. Boericke

"INTRODUCTION Previous investigations of the Boulder City station of the Bureau of Mines have demonstrated that low-grade domestic chromite concentrates can be roasted with carbon to obtain selective reduction of the contained iron, and that the reduced iron can be removed by acid leaching of the roasted products to produce residues with higher chromium iron ratios. Thus, some chromite ores or concentrates that originally contain too much iron to be acceptable for the production of ferrochrome can, by this treatment, be rendered marketable as ""high-grade"" chromite. 3/The present report supplements the earlier work of the Bureau and re¬cords the results of small-scale laboratory tests investigating the effects of:1. Temperature and time of the reducing roast.2. Chromite and carbon particle size.3. Ratio of carbon to chromite in the initial roast mixture.4. Variations in the alumina and silica content of the ore.5. Back-oxidation of the roast product.6. Temperature and time of leaching .of roast product.This work differs from that done previously in that particular emphasis was placed on roast mixtures containing just enough carbon for the reduction of the iron in the chromite, whereas some two and one-half times this amount of carbon was used in the earlier work.In addition to these tests, the mechanism of the production reactions was examined for the purpose of explaining the precance of acid-soluble chromium, which occurs under certain conditions of chromite reduction."

Jul 1, 1945

By Joseph Gersic

In 1989-90, the Bureau of Mines appraised selected high resource potential areas containing gold, rare-earth-element, or pegmatite deposits in or near the Black Hills National Forest. Available mineral resource data were used to construct mine and mill models and to compute discounted cash-flow rate-of-return analyses. Using this information, the economic feasibility of possible operations and probability (in the nonmathematical sense) of exploration and development within the next decade were assessed. High exploration and development probabilities are forecast for gold deposits around existing and permitted mine areas near Lead-Deadwood and west of Galena. The area east of Galena has low to moderate exploration and development probability; the Rochford area has low to high exploration probability and low to moderate development probability; the Keystone area has low to moderate exploration probability and low development probability; the Medicine Mountain area has moderate to high exploration and low to moderate development probabilities. Exploration probability in the Bear Lodge Mountains area is high for rare-earth elements and gold; development probability is low. Exploration probability for gold in the Mineral Hill area is low to moderate; development probability is low. The current level of activity associated with pegmatite mining in the Black Hills would probably not change significantly in the next decade; both exploration and development probabilities are low to moderate.

Jan 1, 1990

By S M. Jowitt, G M. Mudd

"The mining industry is the source for the vast majority of the metal, mineral and energy resources we use on a daily basis. New deposits are discovered over time and are developed into mines before being rehabilitated – a sequence that when repeated can help contribute to the noble notion of ‘sustainable development’, despite the generic concept of mining being the unsustainable consumption of non-renewable resources. The scale of the modern mining industry is immense – from iron ore and coal to base and precious metals, modern mines are sometimes hundreds or thousands of times bigger than their long lost historic ancestors. We also live in a world with emerging and increasing demands for so-called technology metals (aka ‘critical’, ‘e-tech’ or ‘specialty’ metals) that are needed to feed the rapid growth in renewable energy (especially solar photovoltaic panels and wind turbines), consumer electronics, sophisticated military technologies and super alloys, amongst other uses. These elements include the rare earth elements, indium, germanium, tellurium, rhenium, selenium, gallium and many others, most of which had few or no known uses in the recent past. Although the mining industry has been successful in developing ever larger mines and increasing the scale of production, the key issues underlying the future of the industry are declining ore grades, increased tailings and waste rock generation, the presence of toxic or other impurities, balancing the economics of primary and secondary products, stricter environmental conditions, more difficult exploration, increasing community expectations, as well as the processing of more complex or refractory ores, let alone the recent volatility in world commodity markets. Here, we synthesise our recent research on many of these various issues, focusing on the need to link all areas within the mining chain from mineral resources through mining to environmental performance in order to ensure we obtain the most out of our modern mining effort. The paper presents a unique and detailed assessment of the sustainability challenges and opportunities facing modern mining – and geometallurgical thinking is at the heart of this conundrum.CITATION:Mudd, G M, Jowitt, S M, 2016. From Mineral Resources to Sustainable Mining – the Key Trends to Unlock the Holy Grail?, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 37–54 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By R. T. MacMillan

A number of chemical techniques have been applied to manganese ores from three areas of Aroostook County, Maine. Although large tonnages of these ores have been proved, they are low grade, and their exploitation has awaited a suitable beneficiation scheme. As conventional ore-dressing methods had failed to yield satisfactory results, attention was turned to chemical procedures. Leaching with dilute (7-percent) H2S04 extracted over 90 percent of the manganese from ore of the Dudley farm area, consuming 3.8 pounds of acid per pound of manganese extracted. Ores from the Littleton Ridge and Maple Mountain-Hovey Mountain areas were less amenable to this treatment, yielding approximately 80 and 60 percent of their Mn content, respectively. To increase the percentage extraction of manganese in the latter two ores, a number of factors were varied, including (1) acid concentration in the extracting solution, (2) ratio of acid to Mn in the slurry, and (3) preliminary heat treatment of the ore with a reducing agent. Other acids, including HNO3, HC1, and H2SO3, were tried also; however, no significant improvements in the Mn leached from Maple Mountain-Hovey Mountain ore were made. The manganese extraction of Littleton Ridge ore was raised to 90 percent by providing 9 to 11 pounds of HNO3 per pound of Mn in the ore.

Jan 1, 1954

By William H. Waggaman

The United States not only is the largest producer of phosphate rock but also manufactures and consumes greater quantities of phosphate products than any other country. New and expanding uses will increase even further the demand for this basic raw material. Only a small proportion of the total quantity of phosphate rock mined and marketed is consumed directly in a raw or unprocessed state; the vast bulk is chemically treated and converted into [ertilizer] and a wide variety of finished products that play a vital role in [r] national economy. Three fundamental methods are employed in decomposing phosphate rock. 1. Reduction by carbon at high temperatures. 2. Treatment with one or more acids. 3. Calcination or fusion with silica, sodium salts, magnesium minerals, or small quantities of phosphoric acid.

Jan 1, 1960

It is my great pleasure as mayor of the city of Amsterdam to welcome you today to Amsterdam, and to the 10th International Conference on Piling and Deep Foundations. The history of Amsterdam has been connected intimately with your professions of geo-engineering and geotechnology, since its very first days. It is good to be aware that you are part of a very old tradition. The knowledge that we need today to build and renew the city has been gathered over a century long process so that we fortunately can stand on the shoulders of the giants before us. During the centuries people living in this part of the Netherlands have always struggled against the water. The same waters that brought the opportunity for a seafaring country to discover the world and to build an empire in the 17th century were a threat to the low lying Netherlands.

Jan 1, 2006

The primary steel industry of the Prairie Provinces consists essentially of three companies whose total annual melting capacity, as of January 1, 1963, was 333,000 net tons. These companies have steel rolling facilities. In addition, there are five other companies producing steel castings by melting scrap in electric furnaces which, with the plants having rolling facilities, gives a total annual furnace melting capacity of 380,000 tons. Since 1954, the annual production of steel ingots and castings has ranged from a low of 66,588 tons, in 1954, to a high of 211,138 tons in 1961. The present facilities on the Prairies for making steel ingots from scrap, and rolling them to produce light merchant mill products, appear to be sufficient for many years ahead. Steel scrap, as electric furnace feed to make steel ingots for the present line of products, will probably continue to be available at reasonable prices either on the Prairies or from the north-central United States. It is recognized, however, that residual elements in scrap may be-come of greater significance and necessitate more rigid control of scrap quality.

Jan 1, 1963

By J. Dean Warner

Alaska contains many critical and strategic minerals that are scarce in the conterminous United States. Among these are tin, tantalum, and columbium. This Bureau of Mines report summarizes available data on the production, reserves, and occurrences of these minerals in Alaska. Alaska produces about 200,000 lb of tin per year, with historical production since 1901 estimated to have totaled 5,830,600 lb. Measured, indicated, and inferred tin reserves total over 140,000,000 Ib. Much of the tin production has been from the placer mines of the western Seward Peninsula; however, most of the reserves are in that area's lode deposits. Alaskan tin occurrences are part of a belt of tin mineralization that extends along the western coast of North and South America. The Alaskan portion of this "tin belt" comprises placer occurrences and lode occurrences of five major types: greisen, vein, skarn, pegmatite, and volcanogenic massive sulfide. Greisen and vein occurrences are the most abundant, but skarn deposits have historically been the most economically important. Columbium and tantalum have not been produced in Alaska; however, they may be recoverable as byproducts of tin, tungsten, gold, or uranium mining. Approximately 135,000 Ib of columbium oxide (Cb205) are inferred within the Tofty placer deposits in the Manley Hot Springs district.

Jan 1, 1985

By F. J. Reichhardt

Abstract -The Molopo Farms Complex is a major, layered ultramafic/mafic, early Proterozoic intrusion which is totally covered by sediments of the Karoo and Kalahari Formations and situated in southern Botswana and northeastern South Africa. The approximately 3000 m thick, generally fine- to medium-grained ultramafic and mafic cumulates are intrusive into equivalents of Transvaal Supergroup sediments and lavas. Multiphase deformation resulted in tilting and segmentation of the Complex into individual tectonic blocks. Sr isotopes document at least two chemically distinct parental liquids which interacted in a complex manner to form an approximately 1000 m thick rhythmically layered succession which straddles the ultramafic/mafic boundary. Repeated mixing resulted in a complex cryptic layering pattern and numerous sulfide-enriched layers which contain significant PGE +Au concentrations.

Jan 1, 1994

By Alla D. Mah

Titanium forms several compounds with oxygen and also is able to dissolve interstitially about 33 atomic percent of oxygen. Starting with titanium dioxide, reduction becomes increasingly difficult as oxygen is removed; and the final step, be reduction of the titanium-oxygen interstitial solutions, is by far the most difficult. The possibility of reducing titanium oxide, or of purifying titanium containing oxygen, by treatment with certain more volatile metals has been a subject of considerable interest. Theoretical appraisal of the limitations of this possibility, however, has been hampered by lack of adequate information on the thermodynamic properties of the titanium-oxygen solutions. The purpose of the present work was to remedy this difficulty by expanding the thermodynamic knowledge regarding these solutions. The experimental work involved three types of calorimetry and furnished the following information: (1) Heats of formation of 11 titanium-oxygen solutions, in the range of 0 to 10 wt.-percent oxygen, were determined at 298.15° K. As a byproduct, an improved value of the heat of formation of rutile was obtained, which, in turn, led to improved values of the heats of formation of the lower titanium-oxygen compounds. (2) Low-temperature heat-capacity data and entropies at 298.15°K in were determined for 2 representative titanium-oxygen interstitial solutions. (3) High-temperature heat-content data were obtained for 2 titanium-oxygen interstitial solutions to about 1,600° K.

Jan 1, 1957

By W. A. Grosh

In 1951 the Federal Bureau of Mines became interested in the reports of copper-nickel mineralization in northern Minnesota. Several outcrops on the north side of the Duluth gabbro in the Kawishiwi River area were sampled by the Federal Bureau of Mines and George M. Schwartz of the Minnesota Geological Survey. Because these samples showed appreciable amounts of copper and nickel, a 100-pound sample of an un-altered outcrop was obtained for metallurgical testing. Results from this preliminary work were all favorable; therefore, in the fall of 1953 the Bureau of Mines diamond-drilled three holes near the outcrop of the con-tact between the Duluth gabbro and the Algoma granite. A total of 686 feet of NX size hole was drilled, and 100 percent of the core was recovered. Each hole intersected the contact, and the strike and dip for that locality were established. The core was split, and half was used for analyses and further metallurgical tests; the remainder was retained for permanent record in the Bureau of Mines core-storage warehouse.

Jan 1, 1955

By T. F. Myners

This paper, describing the concentration methods and costs of Witherbee, Sherman and Company at Mineville, N. Y., is one of the series of papers on milling methods and costs being prepared by the United States Bureau of Mines. It deals principally with the production of high-grade concentrate. ACKNOWLEDGMENT The author is indebted to C. F. Jackson, principal mining engineer, United States Bureau of Mines, to A. M. Cummings, general superintendent of Witherbee, Sherman and Company, and to the company's engineering staff, for assistance in preparing this paper.

Jan 1, 1932