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By Mark Lawshe, Shosie Serata

The conventional method of mining underground, using narrow rooms and wide pillars, has proven to be poorly adapted to the powerful earth forces that act on underground openings. The high costs of roof bolting, timbering, steel arching, and other means of artificial roof support for both room-and--pillar operations and longwall gate roadways attest to the limitations of traditional mine design. Too often, productivity halts when corners buckle under "cutter roof' stresses, floors heave, and roof strata fall. In the 1960s, an entirely different approach to strata control was developed. The Stress Control Method (SCM) stabilizes failing roofs and heaving floors by removing the cause of failure - highly concentrated stresses around the openings. This is achieved by regrouping three to 10 rooms into a single entry where the rooms are separated by very narrow yielding but stable pillars. SCM employs a specified excavation sequence to redirect earth pressures away from the mine openings. The yield pillars act as scaffolding until a permanently protective secondary stress envelope forms around the entry (lower part of Fig. 1). The result is a dramatic improvement in roof stability and a significant reduction in artificial support costs. Some roof bolting must still be done, mainly to meet Mine Safety and Health Administration (MSHA) requirements. Potash, salt, coal mining The stress control method was first applied to the deep potash mines of Saskatchewan. The new SCM design actually increased room widths to enlarge the stress envelope, redistributing the stress concentration away from the entries (Serata and Schultz, 1972). This resulted in a turnaround from pervasive roof fall/floor heave conditions that threatened operations in the eight new mines opened in the Saskatchewan potash field during the 1960s. In addition to eliminating all roof bolting, SCM successfully stabilized ground conditions and substantially increased productivity over the original design (Serata, 1976, 1982). Similarly, the deep Boulby potash mine of Yorkshire, England, was about to close after various conventional means of combating roof failure had failed. An SCM test area was excavated that resulted in the ground quickly stabilizing without need o artificial support (Serata, 1982; Chilton and Laird, 1982). Another example is the Diamond Crystal salt mine in Louisiana. Here, multiple level mining was being extended from the third to the fourth level downward in the Jefferson Island salt dome. Extensive roof failure was occurring at 396 m (1300 ft) ii the third level. SCM design principles in creased the room size from 24 to 49 m (80 t( 160 ft) on the fourth level at a depth of 457 m (1500 ft). This unprecedented expansion of room width was first questioned and later ap¬proved by MS HA, which expressed satisfaction in seeing the improvement documented by field validation data in 1973. The most recent SUM application to salt mining has been in the Michigan Basin a: Goderich, Ontario. The anticipated abandonment of Domtar Chemicals Group/Sifto Salt Division's deep operation in bedded sale was prevented by a multi-year SCM implementation. The success of SCM in dry mining[lecc] to its application to solution mining of salt This adaptation of the method is now being implemented in bedded salt at Fort Saskatchewan, Alberta by Dow Chemical Co., and in St. Clair, MI by International Salt Co. Application of SCM to solution mining in a salt dome is proceeding at Napoleonville. LA by Dow Chemical. The same technology has also been applied to cavern design for the Louisiana Offshore Oil Port (LOOP), and the compressed air energy storage (CAES)

Jan 1, 1989

This dictionary is published by the Bureau of Mines as a contribution to the mining and mineral literature in the belief that it will fill a recognized need. Several attempts have been made over the years to revise Albert Fay's Glossary of the Mining and Mineral Industry which first appeared in December of 1918. Frank L. Hess of the Bureau of Mines worked on a revision, but his untimely death prevented its completion. Subsequently, the writer was employed to compile and edit this dictionary in cooperation with the technical staff of the Bureau of Mines. Fay's glossary contained about 18,000 terms with 27,000 definitions; the present compilation contains about 55,000 terms with approximately 150,000 definitions. These terms are of both a technical and local nature, and they apply to metal mining, coal mining, quarrying, geology, metallurgy, ceramics and clays, glassmaking, minerals and mineralogy, and general terminology. Petroleum, natural gas, and legal mining terminology, unless of a general nature, has been excluded, as has been foreign terminology where there is an English equivalent. Several thousand Spanish-American mining terms that appeared in Fay's compilation have been removed to make way for the thousands of new English terms that have evolved over the years. Those Spanish-American and Mexican terms still used in the Southwestern United States have been retained.

Jan 1, 1968

By William R. Hardwick

Present information indicates that a copper deposit can be safely fractured with a nuclear explosive and the copper successfully recovered by the in-situ leaching method. The process is not yet at the stage where it can be presented t ) the mining industry as a technique proven in all its aspects, but it is a method with high success potential. Unknown factors must be evaluated by a full-scale test before the economics or the extent of the use of the method by the mining industry can be predicted. Preliminary calculations indicate that the cost of fracturing a copper deposit nuclear explosives may range from l.8 to 55.2 cents per ton or in some case: less than a cent per pound of recoverable copper. Copper may be recovered at less cost than by conventional methods. Deposits with 4 pounds of recoverable copper may be economic and production from a deposit may begin in less than half the time required for conventional methods.

Jan 1, 1967

Study on Dynamic Characteristics of Inertia Cone Crusher and Its Application

Sep 13, 2010

By Hamid Maleki

Prudent design of coal pillars in any mining system requires an estimation of in-situ pillar strength, overburden lateral load transfer capability, and a failure criterion. Pillar strength is typically determined using one of several different empirical pillar strength formulas. For coal reserves in the U.S., a new pillar design method was proposed based on extensive U.S. field measurements in underground mines (7) which accounted for confinement effects. Field measurements in seven U.S. seams indicated highest strength for some Utah mines where the coal seam developed high confining stresses. Lower strength was measured in structurally controlled seams. This method is expanded here including the data from the weaker tertiary coal measure rocks and lower confinement for pillars with low width-to-height ratios. The determination of how much load a pillar is expected to take is partially dependent on the ability of overburden to transfer load laterally; this is useful for selection of panel width and barrier pillars size in select mining applications where long-term stability is required in conservative designs. In caving mining systems, caving of the strata is influenced by geologic, mining and stress conditions and the released energies influences how the pillars react at loads approaching pillar strengths. Overburden deformation and caving mechanisms are analyzed in this paper in multi-panel extractions to enhance the understanding of load transfer, seismicity and coal bump control in deep western U.S. operations.

Jan 1, 2008

By BRETTMANN TRACY

Jan 1, 2000

By Silvio Hernández Aquije

El presente texto señala el descubrimento del yacimiento vanadífero de Minasragra a través del reporte de Yeatman-Berry en 1916 y el de Kett-Sproul en 1931. Así también señala los tipos de mineralización como la mineralización primaria y por impregnación.

Jul 1, 1955

By Luís Marcelo Tavares, Marko Hilden, Malcolm Powell, Grant Ballantyne, Lian Liu

The t10 relationship developed by Narayanan and Whiten has underpinned a number of the JKMRC models and the characterisation of ore competence through impact testing with the drop weight tester. This usefulness is based on a consistent relationship between the t10 value and the overall size distribution that was noted for brittle rocks. However, like all characterisation tests this should be used only when the controlling conditions apply, which in this case is single impact breakage between two metal platens and within the range of sizes in which fragment sizes are normalizable. For any other mode of breakage the relationship should be confirmed before being applied. Soft ores or bimodal ores with widely different competence between dominant components have non-typical breakage signatures. Breakage via single point impact abrasion, compressed-bed breakage, low-energy surface breakage and incremental breakage, to name some of the other breakage modes, do not obey the general t10 relationship, so their outcomes cannot be used to provide a direct comparison. Inappropriate use of the t10 parameter can result in misleading conclusions about efficiency of energy use. These issues and alternative comparison techniques are presented and discussed in terms of choosing appropriate measures of efficiency of breakage, ore competence and energy required for comminution.

Jan 1, 2014

Another major aluminum company announced intentions to follow other domestic producers recent price actions by raising its unalloyed ingot quotes by 3¢ to 44¢ per pound, effective June 1, 1976. COBALT: All final data for 1975 are included in the table for cobalt on page 23. Demand in March increased significantly for the second month in a row, signaling a recovery from the previous year's relatively low demand levels. Imports of cobalt tripled in March over those of February. This should partially offset reduced sales of cobalt excesses from the National Stockpile. Import projections for the next several months have been lowered because transportation difficulties in Zaire are expected to result in reduced shipments.

Jan 1, 1976

By B. H. Clemmons, C. H. Schack

Extractive metallurgy techniques currently employed to recover silver from primary ores and secondary scrap were reviewed and evaluated to identify and delineate metallurgical problems whose resolution would increase the supply of silver from domestic materials. The survey revealed that practically all primary silver is recovered by froth flotation concentration of various types of ores, followed by smelting and refining of the separate lead, copper, and zinc concentrates. Silver losses during the complex processing are, with rare exception, inconsequential. Furthermore, any silver production gain from base metal ores, which contribute about two-thirds of the total primary silver, is directly dependent on improvement in the market for the base metals. Statistical data on new and old silver scrap are wholly inadequate to make reliable conclusions about scrap processing problems and the possibility of increasing the recovery of silver from the many forms of secondary silverbearing materials. The available information indicates (1) that efficient silver reclamation practices are employed by the larger users of silver, and (2) that recovery of additional secondary silver involves solution of problems of collection rather than of processing. Several possibilities exist for limited increases in silver production from primary ores by improvement in metallurgical practices. Specifically, research is needed to (1) solve the problem of recovering silver from the copper ores of the Copper Range district, Michigan; and (2) devise economically feasible methods for recovery of silver from presently marginal or submarginal ores that because of grade, location, and frequently complex nature cannot presently be exploited by conventional techniques.

Mar 1, 1965

By C. R. Tinsley

Investment activity in the Pacific Rim of Fire has seen a phenomenal surge from epithermal gold exploration. Individual countries are attractive because of lower up-front minerals lease costs (US, Canada), better geological prospectivity (Chile, Indonesia), or cheaper equities (Australia). Since the October 1987 stock-market crash, large companies are shedding minority joint venture interests to focus on core businesses. Some vertical integration is evident in Japanese coal investments in the Pacific Rim. This paper does not cover the aluminum industry oligopoly which is multi-national in character nor does it cover the many Canada to US minerals investments. It will be interesting to see if the new US-Canadian free-trade treaty will reverse that investment flow.

Jan 1, 1990

By J. H. Rhee, H. B. Ku, J. S. Lee, H. J. Park, B. S. Jang

A large wedge failure had occurred in the study area which was under construction. Therefore, in order to analyze the potential instability for this rock slope, the authors conducted numerical analysis with DEM and then the behaviour of rock mass was analysed after appropriate reinforce-ments were applied. Ein großer Keildefekt geschah in dem Untersuchungsgebiet, das im Bau befindlich ist. Deshalb, um die potentielle Unbeständigkeit für diesen Felsenabhang zu analysieren, führen die Urheber zahlenmäßige Analyse mit DEM. Und dann wird die Bewegung der Felsenmasse ana-lysiert, nachdem angemessene Verstärkungstruppen angewandt werden. Un grand échec de coin sèst passé dans le région étudié qui était en construction. Par conséquent afin d’analyser linstabilité potentielle de cette pente de roches, les auteurs ont mené une analyse numérique avec DEM. Ensuite le comportement de la masse de roches pourrait être analysée après les renforts appropriés étaient appliqués.

Jan 1, 2003

By Michael A. Piepenburg

The East Side Access (ESA) Project will extend Long Island Rail Road (LIRR) into midtown Manhattan via 11 km of tunnels, a new terminal station and associated support facilities. In addition to the hard-rock tunneling currently underway in Manhattan, soft-ground tunnels in Queens will traverse beneath Amtrak?s Sunnyside Yard and Harold Interlocking, the busiest rail interlocking in North America. This paper details ESA?s coordinated approach to interfacing with both Amtrak and LIRR with regard to the planned tunnels, shafts and related construction beneath or adjacent to the operating railroads. This interface includes integration of railroad staff, extensive presentations, reviews and agreements with the railroads regarding settlement mitigation, real-time automated geo-instrumentation monitoring, ground improvement, and geotechnical/environmental controls.

By C. O. Hawk

A PART of the Bureau of Mines effort to improve the conversion of coal to liquid fuels, batch autoclave tests were made on the hydrogenation of bituminous coal by a dry method, which featured charging the autoclave with dry ingredients only-coal, catalyst, and hydrogen. This innovation, which omitted the liquid vehicle used in earlier work, limited the products to those made from the coal charged. The effects of the common process variables (catalyst, hydrogen pressure, temperature, and residence time) were studied. Tin catalysts showed the highest activity in the widest variety of forms and were the easiest to disperse; dry mixing in the autoclave during the heating-up period usually sufficed. Ammonium molybdate, on the other hand, was inactive when dry mixed, but it compared favorably with the best catalysts known when applied by impregnating the coal with a solution of a molybdenum compound. As a group, metal naphthenates were the most effective; in fact, molybdenum naphthenate was the most active catalyst the Bureau tests disclosed. One-hundredth of a percent of molybdenum in this form (calculated as the metal in weight-percent of maf coal) induced 90-percent conversion of coal. However, because of their high cost, naphthenates have as yet only technical significance in coal hydrogenation. Long residence time and high reaction temperatures tend to increase the amount of thermal decomposition products formed (light hydrocarbon gases and/or char). High hydrogen pressure favors the production of liquids.

Jan 1, 1965

Seventy-three of the 90 naturally occurring elements that are found in the earth's crust are metals or metalloids. The quantities of metals used annually in the United States range from about 100 million metric tons (steel) to a few kilograms (osmium). The recovery of metals from discarded products or industrial process wastes, especially those metals that are used in large quantity, are very expensive, or are unusually toxic, is important to the national economy and to the natural environment. From its inception in 1910, the U.S. Bureau of Mines (USBM) has been the Government's prime source of information on metals recycling, as well as a major innovator in recycling technology. Statistical data on scrap generation and processing have been summarized annually for many years in the USBM's Minerals Yearbook. Most of the data for individual metals discussed in this report were extracted from that publication.

Jan 1, 1993

By R. C. M. Minnitt, W. Dr. Assibey-Bonsu, F. A. Camisani-Calzolari

Born in Bothaville (OFS) on the 26th August 1919, Daniel G. Krige grew up in Krugersdorp on the West Rand. Hematriculated from Monument High School in Krugersdorpin 1934 at the age of 15 and graduated with a B.Sc. (Eng.)degree in mining engineering from the University of the Witwatersrand at the end of 1938 (age 19). In 1938 he joined Anglo Transvaal where he worked on a number of gold mines until 1943, gaining a wide range of valuable practical experience in surveying, sampling and ore valuation. He then joined the Government Mining Engineer’s Department where he worked for 8 years during which time he participated in the uranium negotiations with the British and American authorities and designed the uranium pricing formula for the contracts which led to the establishment of South Africa's profitable uranium industry in the early 1950s. During the same period he began his pioneering work in the application of mathematical statistics to the valuation of new gold mines using a limited number of boreholes and of ore reserves for existing mines. His early papers in the application of mathematical statistics, some republished in French, created world-wide interest that led to the development of the science and concepts that surround the spatial evaluation of mineral resources and reserves known as geostatistics. This technique has contributed to improved ore evaluation techniques as well as the reduction of the financial risks associated with investment in mining enterprises. Furthermore, it led to the recognition of his contributions to the evaluations of mineral deposits through the coining of the term ‘kriging’ that is used to describe a spatial mineral evaluation process known and practised in international mining circles. He continued his work in geostatistics throughout his career as Group Financial Engineer of the Anglovaal Group until his retirement in1981 and afterwards for ten years as Professor of Mineral Economics at the Witwatersrand University. He is still active as a consultant and is a registered Professional Engineer. He has published some 90 technical papers both locally and overseas, some in Russia, and has lectured and participated in international congresses in many countries. His contributions were recognized by the Witwatersrand University through the award of the D.Sc. (Eng.) degree in1963, by three honorary degrees (from the universities of Pretoria, UNISA and Moscow State Mining University), by many awards from the South African Institute of Mining and Metallurgy, the International Association for Mathematical Geology, Die Suid Afrikaanse Akademie vir Wetenskap en Kuns, the SME of the American Institute of Mining Engineers, the International APCOM Council in1999, the University of Antofagasta in Chile, and by the South African President (Order for Meritorious Service, Class 1, Gold). He has served on various Government committees, notably that for State Aid for gold mines (1967/8) and designed the State Aid formula which enabled many mines to survive a period of low gold prices; also various taxation committees, and the mining mission to Iran in 1974. He is a fellow and/or honorary life member of various technical societies locally and overseas, including the Royal Society of South Africa. During the period in the Government service he also handled several of the post-war lease applications in the Free State and Klerksdorp goldfields. The fact that decisions on new gold mines of critical importance to the State and the economy as a whole, were being taken on a limited number of drillholes without any scientific analysis of the risks of failure, stimulated him to start basic research into ore evaluation. His approach was based on the application of Mathematical Statistics to these problems, an approach of which very little was known world-wide at that stage but which had already been initiated in South Africa by Sichel via the lognormal frequency distribution model. In Krige's 1951 paper published in the Journal of the Chemical, Metallurgical and Mining Society of South Africa he covered the statistical explanation of the conditional biases in ore block valuations and stimulated the use by several gold mines of regression corrections for routine ore reserve valuations, a technique which, in effect, was the first use on an elementary basis of what is now known as kriging. His 1952 paper introduced, inter alia the basic geostatistical concepts of ‘support’, ‘spatial structure’,’ selective mining units’ and ‘grade-tonnage curves’. His 1951 paper was based on his M.Sc. (Eng.) thesis submitted in the Department of Mining Engineering to the University of the Witwatersrand, and expounded his pioneering work in geostatistics in more detail. His early research papers that had stimulated interest in several mining circles overseas, were republished in French in1955, resulting in a major research effort by French mining engineers in this field. This, in turn, led to the establishment of the now world-renowned French school of ore evaluation in Fontainebleau, Le Centre de Geostatistique de l’École des Mines de Paris. As the Group’s Financial Engineer at the Anglovaal Head Office until his retirement in 1981, he was responsible for

Jan 1, 2003

By H. W. Gillett

UNLIKE most previous Howe lecturers, I had not the good fortune to be associated with Henry Marion Howe, nor to be directly one of his students. Yet, through his writings, he has been my teacher, as he has of all American metallurgists. Instructive as his writings are-I use the present tense because Howe thought so keenly and reasoned so surely, seeing clearly, as if by intuition, what was hazy to lesser minds, that his writings are still vital-it is not, those books and papers, nor even the minds he trained in his classes, that were his most outstanding service. It was the spirit of Howe in his: approach to the problems of metallurgy, his broad-mindedness and fair-ness, his recognition of the need for theories and hypotheses to explain metallurgical phenomena, his willingness to use them as servants, as well as his questioning attitude-his refusal to accept them as masters-that comprise his greatest service. This most thoroughly warrants the honor the Institute pays each year to his memory. These traits I so respect and honor in any man that I glory in this opportunity to do reverence to him in whom they were so notably united.

Jan 1, 1939

By Jack L. Henry

The ternary system A14C3-AIN-Al203 has been examined to determine compositions which may display desirable high-temperature refractory properties. Powder methods were employed in the synthesis of all test compositions. Forming and sintering behavior was examined and hot-pressing parameters were measured. Several properties were studied for each composition of interest in the system. The properties included hydrolysis rate in moist air, elevated temperature oxidation rate, density, softening point, tensile strength, and rupture strength. In most cases equilibrium was not achieved, and the data are representative of a nonequilibrium system. Approximately 16 separate phases have been observed in the system. Forming behavior and selected properties of five compositions of interest were compared with those of aluminum oxide and aluminum nitride. None of the compositions compared favorably. Oxidation and vaporization appear to be serious drawbacks to the use of these compositions at elevated temperatures.

Jan 1, 1969

By Joey Hoang, Robert Johansson, Tapani Keronen, Mikael Jåfs, Jani Jansson, Mikko Korpi

At the Copper 2016 conference in Kobe, Japan, Outotec introduced a vision for the year 2020, wherein smelting would make use of four digital cornerstones: intelligent instruments, advanced process control, improved information management and transparency of and access to data. Since then, this vision coined the phrase “Fully Automated Smelter” with the mission promising a concept where no manual actions from human operators would be needed during normal smelter operations. Replacing repetitive physical work, collection and analysis of everyday production data has a great potential for further automation and will provide productive ways to improve efficiency and safety of smelters in the future. Therefore, a lot of emphasis has been put into developing solutions to automate these tasks and to move people out of harm’s way. A lot of new equipment, systems and optimization tools are under development. In addition, a lot of effort is going into developing dynamic process models and advanced control systems to interface with the plant automation systems. The goal is to integrate all these concepts to meet Outotec’s Fully Automated Smelter vision. This paper will cover these latest achievements toward this vision and introduce the near-future of digital smelting. INTRODUCTION As is well known already, the humankind is currently experiencing a change, extent of which is broadly studied by the governmental, educational and industrial institutions and parties. The wellbeing and quality of life have traditionally been improved alongside the developments in industrial production, which is now about to enter its fourth revolution. Therefore, the current change is often described as fourth industrial revolution, or industry 4.0 (or industrie 4.0, as named by Acatech, 2013) and can be considered anything from small incremental development to a ground-breaking global reset that will affect everyone’s lives. Many seem to agree, that the scale of change will indeed be big, even significantly bigger than the three industrial revolutions before it (Pellini, Weyrauch, Malho & Carden, 2019; Geissbauer, Vedso & Schrauf, 2016; Jansson, Bjorklund, Lahtinen, Heinonen, Jafs & Fagerlund, 2016).

Jan 1, 2019

By Alan K. Burton

Massive increases in the productive capability of open pit nines after World. War II were in a large part made possible by the introduction of ever larger trucks and the supply of a seemingly bottomless ocean of inexpensive and readily accessible oil. Over a period of about 25 years, a variety of technological developments permitted a tenfold truck payload increase, from about 32 tonnes (35 tons) to 320 tonnes (350 tons). There is no, doubt that this was a remarkable achievement resulting in impressive benefits of scale as well as the ability to control what would otherwise have become an intolerable traffic congestion problem in today's large open pit mines. It became fashionable and economically possible during this time to mine large quantities of low grade material and to tolerate very high stripping ratios. As tine has gone by and as easier to get at and higher grade deposits have been depleted, ore grades have tended to decline while stripping ratios have increased. The alternative to reduced revenues has been an ever increasing demand to step up production which in turn has led to a continuing demand for ever larger and larger trucks. While a larger truck has had the effect of reducing the cost of the operator per unit of material moved and of reducing traffic congestion, it has not specifically addressed the subject of fuel cost.

Jan 1, 1981