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By Roy S. Nutter

The automation of coal mining must occur in a manner that is economically beneficial to the industry and that enhances the safety of the underground and surface workplaces. The work at WVU over the last five years in applying expert systems and neural network controlled autonomous robotics provides the mining industry with tools that when properly applied should clearly lead to mine-wide management and operational improvements and should also contribute to a higher awareness of safety issues by all work crews. This work includes the development of MMSS (Mine Management Support System) and the detailed development of autonomous robotics utilizing neural networks for mining systems.

Jan 1, 1993

By Peter Dowden, Trevor Carter, Allan Moss, Bruce Downing, Richard Beddoes

Traditionally (with a few exceptions) tunnel boring machines (TBMs) have been utilized on tunnel projects where the risks associated with deep tunnels (rock burst, squeeze, etc) are low (or expected to be low). This has generally been due to the extremely adverse consequences of entrapping or damaging a TBM under such conditions; but also due to the relative difficulty of dealing with these ground conditions in the confined working area of a TBM, in comparison to a drill and blast heading. This paper review the constraints of operating a TBM in a deep tunnel and discusses related project experience, particularly recent and current experience with TBMs in the deep Alpine Base Tunnels. Potential future applications of TBMs in the development of large, deep underground mines are also discussed.

Jan 1, 2007

By D. Harry Chambers

The Bureau of Mines, through a memorandum of agreement with the Department of Defense, conducted research to recover silver from aircraft scrap. Silver was recovered by an electrolytic method from stainless steel honeycomb sections separated from the aircraft. These sections had been constructed by sandwiching a stainless steel honeycomb core between stainless steel sheets and then brazing the assembly with a silver alloy. Over 300 pounds of silver was used in the B-58 bomber, concentrated in certain honeycomb sections of the aircraft. Following shredding of the aircraft parts, an average of 95 percent (ranging 67 to 100 percent) of the silver was recovered in a single electro-refining step. After the electrorefined product was magnetically cleaned, purity of the recovered silver was greater than 99.3 percent.

Jan 1, 1980

By V. F. Parry

Subbituminous coal or lignite when stored in random riles or in ordinary bins in which the temperature fluctuates and air circulates quickly undergoes objectionable physical and chemical changes, which decrease the utilization value of the fuel and increase its tendency to ignite spontaneously. Slacking takes place, and the heating value decreases. Those changes are accelerated by fluctuations of temperature and by circulation of air through the storage space. When such coals are exposed to the weather they lose moisture rapidly. If evaporation from the surface of a lump proceeds at a faster rate than that at which it is replaced by moisture from the interior, the rate of shrinkage at the surface is greater than that at the interior; consequently stresses are generated at the surface which cause the coal to disintegrate. Likewise, when moisture is absorbed by the air-dried surface the outside layers expand at a faster rate than the interior, which results in further break-down. As these cycles are repeated the lump may disintegrate completely. Therefore, successful storage of low-rank coals depends on control of the factors that influence change of moisture.

Jan 1, 1941

By Cale J. Dubois

At Cameco Corporations' Cigar Lake Project, large excavations are developed on the 480 Level and 500 Level must remain stable for at least 15 years to host underground processing infrastructure. Following the successful dewatering of the mine in October 2009, subsequent internal rockmechanics investigations augmented by third party technical investigations; determined that to keep the back of the Water Flush Crusher/Run-of-Mine (WFC/ROMs) excavation stable; required a rehabilitation strategy to mitigate deterioration/deformation of the WFC walls and intersection pillars. The mechanism of failure propagating the movement of the excavation walls is understood to be controlled by the presence of a dominant E-W striking and steeply dipping foliation within a relatively weak and mildly altered rockmass sub-parallel in strike with 14 meters high walls and an intersection span approaching 15 meters. The application of open and resourceful communications between site mining engineers, geologists, contract mining staff, construction management experts, corporate mining and civil engineers, and third party technical experts resulted in a multi-faceted short-term ground support strategy consisting of standard bolting and screening, deep-seated modified-strand cable bolts coupled with heavy gauge mesh straps, rockmass reconditioning using low-pressure grout injection, and horizontal cable-lacing for the intersection pillars applied in lifts using a top-down methodology. The intention of the short-term strategy was to stabilize the excavation so that a long-term structural steel support installation - consisting of composite concrete walls, and arch support applied to the side walls and crown of the back - could be constructed safely. This paper summarizes the evolution of the short and long-term ground support strategy and criteria for the WFC/ROMs excavation developed using elements of civil, mining and hydrogeologic design.

Nov 1, 2011

By B. S. Terry, C. L. Harris

After measuring the kinetics of Ni reduction from a SiO2-saturated fayalite slag into a Cu-based metallic phase on a laboratory scale, a general model was developed that is capable of simulating mass transfer to and from metal-slag, slag-gas and metal-gas interfaces for multiple species. The model was used to simulate the reactions that occur when Cu and Ni are reduced from fayalite-based slags into a Cu-based metallic phase. Good agreement was achieved between model predictions and experimental data

Aug 1, 1995

The original manuscript of section 2 of this series of miners' circulars devoted to accident prevention in bituminous-coal mines was completed in September 1944. At that time roof bolting had been tried with some success in the lead-mining district of south-eastern Missouri, but information on the subject was so fragmentary that it was not included as a method of roof support. References to roof support in bituminous-coal mines, therefore, were confined almost entirely to conventional timbering methods. In 1947 the Bureau instituted a research program and intensive study of the general problem of roof control, which emphasized roof-bolt application. The rapid increase in mechanized mining following the close of World War II provided the impetus for the Bureau's roof-control investigations, because the vertical supports used with conventional timber restricted the maneuverability of mechanical face equipment, and the industry wanted to explore every possible method of eliminating interference with the production cycle to gain full advantage of mechanized mining. Moreover, the accidental dislodgment of vertical supports greatly increased the roof-fall hazard. As roof falls have killed and seriously injured more mine workmen every year than any other cause or classification of injury since records have been kept, the Bureau assumed this investigative leadership with the prime objective of substantially reducing the annual toll from falls of roof, including falls of rib and face.

Jan 1, 1958

"These tentative coal mine inspection standards have been prepared as a guide for the Federal inspection of coal mines of the United States. Much time and thought have been spent by various members of the Safety Division in the preparation of thses standards, and it is believed that compliance with them eventually will be possible in most mines. In many instances objections will be raised to them owing to long-established mining customs and practices that are inherently of dubious safety and to a natural inclination to oppose change. In other instances there will be valid objections due to conditions not foreseen at the time these standards were prepared. Or there may be substandard conditions and practices due to original mine layouts that it is not practicable to change during the lifetime of the mine; in such instances it is likely that some effective measures are or can be taken toward lessening hazards.With the rapid change in mining methods some of the standards may become inapplicable and it may be advisable to revise them to meet the new conditions. Therefore, questions regarding these standards and suggestions regarding new standards should be brought to the attention of the supervising engineer of the Coal Mine Inspection Division so that modifications of and additions to these standards may be made from time to time.In many respects these standards exceed the provisions of the various State mining laws, and some may conflict with the laws of some States. In cases of conflict, the intent is not to advocate noncompliance with State laws but to suggest that it may be desirable for the State to reconsider such laws or safety orders.Although an effort has been made to word these standards so that they may be readily understood, nevertheless, a reasonable interpretation should be placed upon them. In fact, in numerous instances the words reasonable"", ""suitable"", and ""properly"" are used in recognition of the fact that reason- and sound judgment enter into the carrying out of the safety endeavor.The policy of the Bureau on some vitally important safety matters in mines is set forth in its published Safety Decisions. These decisions have been consulted and used in the preparation of these standards. These decisions also are now being reexamined by its Mine Safety Board."

Feb 1, 1942

By Floyd C. Bossard

Major air-cooling facilities have been installed and are operating underground in U.S. copper mines (at Butte, Montana and Superior, Arizona), South African gold mines, European coal mines, Zambian copper mines, Kolar gold mints in India, Coeur d'Alene mines of Idaho, plus other locations. Mining districts that utilize spot cooling and local air-cooling facilities would increase the above listing many times. The principal objectives of underground mine air cooling systems are to; 1. Extract heat and water vapor from the mine air and provide for their removal from the mine via (a) water pumped to surface or (b) discharged mine exhaust air. 2. Provide acceptable artificial ambient conditions for efficient working mine development and production areas. 3. Recondition used air, thus supplementing the limited mine ventilation balance. In deep South African gold mines, when rock temperatures exceed about 105°F, cooling of underground air becomes necessary for the poorly ventilated sections of the mine. By U.S. standards, air conditioning in poorly ventilated mines usually commences when the virgin rock temperature exceeds 100°F. On the other hand, well ventilated deep vein-type mines in the U.S. have been able to forego general cooling of mine air until the mines have been extended to such depths that the virgin wallrock temperatures have exceeded 115° - 120°F. It must be noted that spot-cooling of selected development headings may be required in many mines where rock temperatures exceed 100°F. Such local air-cooling practices permit the driving of long headings for exploration or extended development prior to holings which result in establishment of primary ventilation circuitry. The following summary reports on current practices of cooling and dehumidifying mine air. General system descriptions with important details will hopefully permit the reader to gain an understanding of the subject. A list of references is provided for this serious investigator who desires a more thorough knowledge-base and who is responsible for the design of a mine air-cooling system.

Jan 1, 1973

By Nicolas Denies, Gust Van Lysebetten, Bart Lameire, Jan Maertens, André Vervoort, Noël Huybrechts, Flor De Cock

"Abstract Originally developed for ground improvement works, the deep mixing method (DMM) has increasingly been applied in recent years for the realization of soil and water retaining structures and as alternative to traditional foundation solutions. From practice, there is a real need for practical guidelines dealing with the execution, the design and the control of such applications. With the aim of developing such guidelines, the BBRI ‘Soil Mix’ project was initiated in 2009. Within this research project, deep soil mix (DSM) material from 38 Belgian construction sites has been tested. In spite of the large advances in the mechanical characterization of the DSM material, one major issue remains the representativeness of the typical core samples in comparison with the real scale behavior of the soil mix elements. There is among others the question of the influence of the unmixed soft soil inclusions on this behavior and the issue of the scale effect which must be considered in the design. In order to investigate these questions, 8 large scale UCS tests and 17 large scale bending tests have been performed on excavated soil mix elements. The present paper discusses results of this experimental campaign, presents some research perspectives and highlights different aspects related to the design of soil mix elements for the realization of retaining wall or foundation solution.INTRODUCTIONSince several decennia, the deep mixing method (DMM) has been used to improve the strength and deformation characteristics of weak soils. In recent years, deep mixing has increasingly been applied – in Belgium and in other countries – for the realization of soil and water retaining structures and alternative foundation concepts. With regard to the execution of the DMM, one can refer to the European standard EN 14679 on deep mixing (2005) that was elaborated under the umbrella of CEN TC 288 “Execution of special geotechnical works”. However, from practice, it has been experienced that this execution standard does not provide enough pragmatic information and guidelines, in particular for the more recent applications of the deep mixing method (with retaining and bearing functions). The same need by the sector for guidance rules linked to design aspects in the context of Eurocode 7 was experienced as well. With the aim of developing such guidelines and in order to provide feedback to the European standardization platforms, the Belgian Building Research Institute (BBRI) has initiated the BBRI ‘Soil Mix’ project (2009-2013) in collaboration with the KU Leuven and the Belgian Association of Foundation Contractors (ABEF), the Belgian branch of the EFFC. Within this research project, deep soil mix (DSM) material from 38 Belgian construction sites, with various soil conditions and for different execution processes (CVR C-mix®, TSM and CSM), has been tested (Denies et al., 2012)."

Jan 1, 2014

By R. L. Schmidt

One of a series published by the Bureau of Mines covering research investigations in rock drillability, this report of field drilling results extends earlier laboratory findings and provides a relatively simple procedure for predicting percussive drilling rates with reasonable accuracy. Two percussive drills mounted on a truck were used to drill a total of 25 rock types, and the results were used to develop a prediction equation. The equation was tested on a set of unrelated laboratory percussive drilling data, and the comparison between predicted and actual rates is shown in tabular form.

Jan 1, 1972

By F. D. DeVaney

Metallurgists and coal-washing engineers have used heavy liquids for years in studying the characteristics of ores and coal. By such means true separations can be made between the various specific-gravity increments in the materials examined. To use of heavy liquids has permitted determination of the possible grades of tailings and concentrates by specific-gravity methods on any particular size, and therefore the size to which the ore must be crushed to free the valuable material. The simplicity of float-and-sink separation and the high degree of efficiency attained in the laboratory are factors that commend the method for commercial concentrations.

Jan 1, 1940

By S. V. Ulianov, A. Y. Senchenko, E. M. Kurchevskaya

"A process sample of old copper-containing tailings (-2.0+0 mm) from an iron-ore plant was tested in TOMS institute in order to develop a process for copper concentrate production. The study of tailings material composition indicated that -0.2+0 mm fraction was efficient and contained 97.26% of copper. Copper is predominantly concentrated in chalcopyrite which is present both in free form and in intergrowth with ore and rock-forming minerals. Study of chalcopyrite using an optical microscope and Qemscan SEM determined that the most grains surface was covered with oxide films. Additionally, a lot of grains had micropores on their surfaces that indicated a partial mineral leaching. The oxide films did not make it possible to float copper minerals from head material. It was recommended to apply an attrition operation to restore chalcopyrite floatability. In order to increase selectivity a regrinding stage for a primary copper concentrate was introduced to obtain P80 26 um. Taking these recommendations into account a flotation flowsheet was developed to process the old Cu-containing tailings. The flowsheet allowed us to obtain a concentrate with 23.5% Cu content at 71.5% recovery.INTRODUCTIONStudy of material composition is an important prerequisite for development of a minerals processing technology. Mineralogical study contributes to search for an efficient technology to recover valuables and for prospective methods of minerals processing.The use of such up-to-date analysis methods and equipment as Qemscan and Mineral-C7 allows one to determine minerals size, liberation degree, and mineral associations. Mineralogical data can reveal reasons for hard processing of minerals prior to development of the process.The advanced process mineralogical methods used to study Cu-bearing pond tailings indicated several factors that influenced development of the process. The first one is a barren size fraction which is to be removed from the process in order to considerably reduce the costs connected with grinding. The second is the presence of films on chalcopyrite surface; in this context, a preliminary attrition of the material was recommended. The third factor is finely disseminated Cu minerals in sulphide and in the rock, which predetermined selection of particle size for flotation. All these data led to significant decrease in time required to develop the process technology. The developed process flowsheet based on the obtained mineralogical data is present in Figure 1."

Jan 1, 2016

By Felicia F. Peng

Employing the combination of two types of polyelectrolyte might become necessary to enhance both settling rate of the flocs and water clarity of fine particle suspension in high capacity thickening process. The sequence of addition, mixing, type and dosage of polymer affect the overall performance and capacity of a thickening process. For the sedimentation of copper flotation tailings, the cylinder test results showed that two different techniques may be used to achieve the required performance including high settling rate of flocs, underflow density and overflow water clarity, by either adjusting pH prior to anionic polyelectrolyte flocculation, or using a combination of polymer flocculant and coagulant (dual polymer system). The dynamic thickening testing results showed that only the approach using a dual polymer system is able to meet the required performance. The effects of polyelectrolyte dosage, the sequence and numbers of polyelectrolyte addition, feed concentration, bed level and rake speed on the settling rate, underflow solid, and water clarity were studied in cylinder test and a laboratory dynamic thickening unit with various conditions related to the thickening process. The dynamic test is especially valuable in evaluating the addition and mixing of polymers. The results were evaluated quantitatively, using total suspended solids in supernatant, underflow density and capacity per unit settling area per unit time as the measure of effectiveness. The objective of this study is to quantify and explain some of the parameters involved in the sedimentation of copper flotation tailings.

Jan 1, 1997

By A. T. Iannacchione

Underground limestone mines typically use the room-and-pillar method of mining in the generally flat-lying limestone formations. In some cases the dip may exceed 5° which can result in unique roof instability problems. Stability may be further exacerbated by the presence of horizontal tectonic stresses. Field studies and numerical model analyses are combined to assess the affect of the dip in various stress conditions. The results showed that where the horizontal tectonic stresses are sufficient to cause intact rock failure, increasing dip results in increased failure potential. The effect of the dip is greater when the maximum horizontal stress is parallel to the dip. Two case studies are presented and evaluated against the findings of stress analysis results. The study showed that the empirical rules of orienting headings parallel to the maximum stress are generally applicable to dipping excavations, except when mining in the up-dip direction. The importance of accurately determining the orientation of the maximum horizontal stress is emphasized because the window of favorable orientations relative to the stress is small.

By Z. D. Hora, W. N. Hamilton

Introduction Some unique opportunities exist for industrial minerals in British Columbia and Alberta. The region's diversified geology, particularly in British Columbia, offers favorable environments for a rich variety of mineral resources. Many minerals have been produced for years. For some, however, the level of production is far less than the potential. Others have had production in the past, but are not currently produced. Still others are known to exist and may have been actively prospected. But they are not yet developed. In addition, a number of speculative possibilities have recently come to light. The potential significance is not fully confirmed, but is suggested in showings in favorable geologic settings. Location and geography British Columbia and Alberta are the westernmost provinces in Canada (Fig. 1). The region overlaps two major physiographic divisions of the country, the Cordillera and the Interior Plains. It also takes in a small segment of the Canadian Shield on the east. The entire territory is greater than 1.6 Mkm2 (618,000 sq miles). Most of British Columbia lies within the Cordillera, a mountainous belt some 800 km (500 miles) wide. The belt is made up of three main physiographic components, the Eastern, Interior, and Western subdivisions. The Eastern subdivision embraces the rugged, linear ranges of the Rocky Mountains, elevations between 2600 and 3300 m (8530 and 10,800 ft). They form a 100-km (62-mile) wide band straddling the BC-Alberta border and extending northwest across northern British Columbia. The Interior subdivision includes several ancient mountain ranges but is dominated by an intermountane plateau area of low relief (average elevation 1200 m or 3900 ft). The Western subdivision is dominated by the Coast Mountains (elevations between 1800 and 4000 m or 5900 and 13,123 ft). These form a band about 175 km (110 miles) wide into which are sculptured the spectacular fiords of the BC coastline. Alberta lies largely within the Interior Plains, a prairie region of low to moderate relief (elevations between 200 and 1200 m or 650 and 3940 ft) formed of nearly horizontal bedrock strata. The Plains surface rises gradually to the southwest toward the deformed belt of the Rocky Mountains, where the bedrock strata are upturned, folded, and faulted. To the east, the Plains merge with the Canadian Shield, which exposes the Precambrian crystalline basement of western Canada. The total population of the BC-Alberta region is about five million people. Minerals, forestry, and agriculture are the primary industries here. It has well developed infrastructures to service these industries. British Columbia is third among the Canadian provinces in metal mining - $1.1 billion in 1985 - and first in forest products. It is also second in hydro-electric power development. Alberta leads all provinces in total mineral production, largely due to its extensively developed petroleum and natural gas resources - $26.2 billion in 1985.

Jan 12, 1987

By Ronald Benito

El presente texto señala el algoritmo basado en grafos como la técnica que determina el límite óptimo de minado a cielo abierto. Por ello, se adaptó la técnica de Lerchs y Grossmann y intermedias (algoritmos) y fue usada para crear nodos, arcos y estructuras de árboles en tablas para determinar la máxima cerradura de un grafo.

Sep 1, 2013

The principle activities of the Explosives Research Laboratory from July 1, 1961 to June 30, 1962, are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1962; in general, the research reported in these publications antedates the report period. Part 3 gives the results of an investigation which, although too limited to warrant separate publication, merits presentation in some detail because of current interest in ammonium nitrate-fuel oil compositions.

Jan 1, 1964

By Charles Steed

The design of pillars in room and pillar operations is always a compromise between factor of safety and ore recovery. In actively mined and accessed areas the stability of pillars must be sufficient to support the roof, providing safe working conditions for men and equipment, while optimizing ore recovery. As a reserve is mined out, and if conditions are favourable, pillars are often removed to increase recovery. Considerations for pillar removal include value of the ore, the effect on immediate and overall mine stability and the safety of the mining operations as well as the consequence of disruption of overlying strata and surface infrastructure as the support of the pillars are removed. Many parameters influence pillar strength and the contribution of the pillar to ground support. These include seam height, seam depth, seam inclination, room span, quality of rock, time, etc.. Empirical, analytical and numerical modeling methods are commonly used to optimize pillar sizing and placement and predict influence of pillar extraction or reduction on ground stability. Practical examples for pillar design and optimization in low seam gypsum mining operations and optimizing sequencing of pillar extraction in thick seam metal mining operations are outlined.

Jan 1, 2003

By A. H. Bell

Continued low prices and restricted markets for crude oil discouraged drilling activity in Illinois oil fields during 1933. Only 36 wells were completed in the state, the smallest number since 1904, and of these the majority were scattered wildcat wells, only 10 having been drilled in producing fields (Table 2). Production was curtailed approximately 40 per cent for the first half of the year. During July, August, and the early part of September there was no restriction on production. On Sept. 8, under the "code of fair competition for the petroleum industry," the quota of allowable production for Illinois was fixed at 12,000 bbl. per day. The state's production in 1933 was 9 per cent less than in 1932. What it would have been had there been no curtailment of production and if economic conditions had permitted a normal amount of cleaning out and repairs to wells, it is not possible to estimate, but it would no doubt have been considerably more than the actual figure. No new pools or new producing horizons were discovered in 1933, but the deepening of a Robinson sand well in Crawford County to the McClosky "sand" horizon (St. Genevieve limestone of the Lower Mississippian) resulted in a production of 3 bbl. per day (Fred Patchel, Savilla Shipman No. 5, NE. 1/4, SW. 1/4, sec. 26, T.6N., R.l3W., deepened from 1122 to 1388 ft., to be tested to the McClosky horizon, and, owing to the rapid variations in porosity within short distances, as shown in the Lawrence County field to the south, one test may not be considered as proving or condemning any large area. The average price of Illinois crude oil in 1933, calculated from the posted prices as published in the Oil and Gas Journal and Oil Weekly, was $0.862 per barrel. This compares with a calculated average price of $1.032 in 1932 and 0.852 in 1931. The total value of Illinois crude oil produced in 1933 obtained by multiplying the average price (0.862) by the total production (4,227,000 bbl.) was $3,643,674. Of the 26 wildcat wells drilled in 1933, only one was drilled on known favorable structure. This was the Walmar Oil Company's William Pepple well No. 1, sec. 12, T.4N., R.12W., Hancock County, which tested

Jan 1, 1934