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Develop an environmentally feasible method of mining shallow oil sands without removing overburden. Approach Oil sands are extracted through a single borehole by cutting into the sands around the borehole with a high pressure water jet, and pumping the resulting slurry to the surface. Although oil can be extracted from shallow fields by open-pit mining methods, this type of mining may create significant environmental impacts, including; (1) disruption of the surface, (2) accumulation of waste rock piles, (3) accumulation of tailings, (4) damage to the ground water quality, and (5) surface water pollution. The borehole mining system developed and successfully field tested by the Bureau of Mines offers a method for extracting oil from oil sand with minimal disturbance to environmental quality. (For examples of other applications of borehole mining, see Technology News Nos. 95, 63 56, and 48.) How It Works Prior to the start of mining operations, baseline conditions for ground subsidence and ground water quality are established at the test site so that the degree of subsidence and changes in ground water quality can later be determined. Oil sands mining is conducted using the Bureau of Mines borehole mining system. The borehole mining tool consists of a 12-inch-diameter pipe string and accessories capped with a three passage swivel terminated with a mining section. The mining section has an auger at the bottom. Four slurry inlet holes and an eductor are located above the auger, and a single cutting nozzle is located near the top of the mining section. The tool generates a high velocity water jet that erodes and slurrifies ores. The slurry is drawn into the inlet of the eductor which lifts the slurry to the surface where it is deposited into a slurry discharge sump. To detect evidence of subsidence, surveys of the land surface are made at regular intervals during, and until 30 days after, the termination of the mining operations. Samples of ground water from the borehole and two adjacent monitor holes are taken on alternate days during the mining operations, and are later analyzed to determine if any ground water contamination has occurred.

Jan 1, 1981

By L. B. Pankratz

Enthalpies above 298° K were investigated for four crystalline sodium borates by copper-block drop calorimetry. Determinations were made to 1,200° K for NaB02, 1,003° K for Na2B407, 1,005° K for NaB305, and 1,046° K for Na2Be013. No phase transitions or other thermal anomalies were found. The enthalpy determinations, when combined with known heats of formation at 298° K and other supplementary data, enabled the calculation of the heats and free energies of formation of the compounds to their melting points. Values of relative enthalpies, entropies, heat capacities, free energy functions, enthalpies of formation, free energies of formation, and equilibrium constants of formation were tabulated at even temperatures.

Jan 1, 1971

By N. S. Dalal, V. Castranova, K. Van Dyke, V. Vallyathan

"IntroductionInhalation of crystalline silica is often associated with the development of pulmonary disease (Ziskind et al., 1976). Recently, it has been proposed that freshly sheared silica .may have surface properties that make it more reactive with lung tissue than aged silica, and that this unique reactivity ·of freshly crushed silica enhances its pathogenicity. A recent study in our laboratory strongly supports this theory (Vallyathan, et al., 1988a; 1988b). We found that grinding of silica cleaves bonds in a silica tetrahedral lattice generating reactive free radicals sites on the surface of the silica particles. The presence of surface radicals on freshly ground silica was monitored by electron spin resonance (ESR) spectroscopy. The ESR signal generated from fresh silica in air is characteristic of Si-0 and Si radicals. Evidence, i.e., the ESR signal after the addition of a spin trap (DMPO) and its sensitivity to ethanol, indicates that these silicon-based surface radicals can react with water to form hydroxyl radicals (OH). Results also indicate that these surface radicals make fresh silica more cytotoxic than aged silica; i.e., fresh silica causes more membrane damage as evidenced by hemolysis and lipid peroxidation. Therefore, the presence of reactive sites on the surface of freshly cleaved silica may play a significant role in its pathogenicity.If surface· free radicals are related to cytotoxicity, then screening dusts for the existence of such radicals may predict their relative pathogenicity. Since an ESR spectrometer is not available to many laboratories, the objective of this study was to develop a quick and simple technique to monitor the existence of reactive surface sites on dust. The technique chosen was the measurement of chemiluminescence using a liquid scintillation counter; i.e., an instrument which·would be accessible to most investigators."

Jan 1, 1989

By E. G. Valdez

The Federal Bureau of Mines, in cooperation with Ford Motor Co., investigated the recovery of polyurethane foam and other assorted plastics from the nonmagnetic reject of automobile shredders. Preliminary studies were con-ducted on a 1957 hulk augmented with additional foam and assorted plastics. The proposed flowsheet developed by the Bureau from the preliminary studies consists of a combination of screening, water classification, and gravity separation. The process was then tested on reject from two shredded 1972 cars. All of the foam and between 52 and 70 pct of the assorted plastics were recovered. The composition of the reclaimed foam concentrates ranged from 46 to 66 pct foam; the concentrates were hydrolyzed in laboratory tests by Ford Motor Co. to produce a reusable liquid mixture of polyether glycol monomers and toluene diamine.

Jan 1, 1975

By Ruth A. Holmes

A Bureau of Mines method for recovering nickel, cobalt, and copper from low-grade domestic laterites is described, which includes the unit operations of solvent extraction and electrowinning. Previous Bureau work indicated that addition of Na2S04 (sodium sulfate) to the nickel electrolyte improved current efficiency in nickel electrowinning. The present study determines the compatibility of Na2S04 with nickel strip-ping in the solvent extraction operation of the Bureau method. The effect of adding 100 g/l Na2S04 on nickel stripping, phase disengagement, and pH was determined in comparative laboratory-scale tests. In continuous-circuit testing, Na2S04 reduced stripping efficiency to the extent that five, instead of four, strip stages were required for complete stripping of nickel from the loaded solvent. In tests made in a phase-disengagement cell that had a variable settler area, the addition of Na2S04 did not significantly affect phase separation characteristics. The pH of the nickel electrolyte in the temperature range of 20° to 65° C was also unaffected by the addition of Na2S04. An economic evaluation showed that the energy saved by adding Na2S04 to the electrolyte would more than offset the cost of adding another stripping stage.

Jan 1, 1983

By C. H. Elder

An experimental degasification program using a vertical borehole and vacuum pump to drain gas from the gob area of a longwall panel was successful at Bethlehem Mines Corporation, Cambria Division, No. 33 coal mine. Sixty-one million cubic feet of methane has been exhausted during a 9-month period. Daily production time in the panel increased as a result of lower methane levels in the returns. Removal of large quantities of methane in this way and the exclusion of it from the ventilating system will provide reduced cost in mine ventilation and provide a safer environment for the mine.

May 1, 1969

By R. V. Ramani, K. V. K. Prasad

"This paper was the subject of a cross-disciplinary presentation under the chairmanship of Dr A.M. EdwardsManagers need quality information for effective decision making. This demand, at the present time, is being fulfilled by the increased use of computers via information systems, decision support systems and management information systems. The idea of incorporating intelligence into computers to aid decision-makers has been evolving for over two decades. In recent years, significant progress is reported on applications to business and sciences. In engineering functions, the Artificial Intelligence approach that seems to have great potential is the application of Knowledge Based Systems.The primary objective of this paper is to identify domains in mining engineering where application of knowledge based systems could be beneficial. Incorporation of the expertise required during the analysis and interpretation stages of an engineering design problem through knowledge based systems is recognized as an area of significant benefit. To this end, the components of knowledge based systems for mine ventilation and strata control design are described. The potential applications and limitations of knowledge based systems are outlined. IntroductionCorrect decisions are the key to success in any enterprise. Scope of decisions varies with the echelons of management hierarchy. The decisions of top management are strategic, relating to the long-term future of the organization. In a mineral organization, these deal with such issues as the acquisition of a new mineral property or the diversification of the business to exploit additional markets. At the operational level, a manager is concerned with decisions pertaining to day-to- day eventualities related to production activities and other short-term needs. In either case, the prerequisite is the timely availability and use of information. The difficulty involved in decision-making depends on the situational aspect. In. many cases, the decisions to be made under given conditions are fairly straight-forward and standard. This may be due to experience gained from decision-making in similar situations in the past. In fact, many decisions in operations management are either repetitive or routine."

Jan 1, 1989

By C. Travis Anderson

"A recent critical study by Ralston3 of the iron system points out the importance of and necessity for work upon the preparation of ferrous oxide. Not only are ferrous oxide samples desired for determination of the important physical and chemical properties, such as specific heats and heats of formation, bat also information on the stability and behavior of this material is of considerable technical importance. Related. problems where the properties of Fe0 are important have to do with desulphurization of iron, the formation and occurrence of magnetite in copper smelter slags, and sulphur elimination in copperFerrous oxide also has valuable catalytic properties, as is demonstrated in nitrogen fixation.Pure ferrous oxide has never been prepared in quantities large enough to furnish adequate physical and chemical data on its properties. Only two or three experiments4 have produced a fraction of a gram in a state approximating purity and have collected evidence that has been sufficient proof of their having done so. Ferrous oxide is stable only above about 570°C., and below that splits into magnetite and iron according to the reactionUp to about 1920, those who had endeavored to prepare FeO made no provision for rapid chilling, so that although their product. may have had the proper iron oxygen ratio for FeO, in reality it-probably did not consist of pure FeO. The above reaction is reversible; above 570oC. magnetite and iron are supposed to recombine almost completely, and if so, should constitute a direct and easy method of preparation. The data, however, were somewhat conflicting, and the extent to which the reaction goes in either direction needed checking. Preliminary experiments on the interaction of molten Fe304 with solid Fe gave Fe0 of about 85 per cent purity, corresponding to. the approximate purity obtained by some previous investigators. The present work is concerned chiefly with the results cf repeated interaction between partly reduced magnetite and iron, and the calculations which may be made from such results. Repeated treatments are necessary, because molten impure ferrous oxide and iron can not be kept in contact for more than short periods of time."

Oct 1, 1928

By Roy T. Sorensen

This Bureau of Mines report presents the results of a study to rank technologies for extraction of alumina from bottom ash and coal shale. The available literature on composition and availability of coal waste was reviewed, and papers pertinent to alumina extraction are referenced. Types of coal waste were categorized by method of waste generation, coal content (heating value), location, coal type (ash nomenclature), and alkaline earth content. The differences and similarities among the categories of coal waste are summarized as to factors that my affect aluminum extraction, especially factors concerning chemical composition, current production, storage problems, and accumulated tonnage. Data available on physical characteristics and mineralogy did not correlate well with the individual categories of coal waste, and discussion on these two aspects is limited to the differences between coal ash and coal shale.

Jan 1, 1983

By L. C. IlsLey

The first thing to consider in prevention of electric shock is the voltage of the circuit. No person can be sure that he will not be killed, even from a 110-volt circuit, if he makes proper contact with the circuit so as to cause the maximum current to pass through his body. As the voltage is increased to 250 volts, 500 volts, or 2,300 volts the danger from contact with the electric circuit is increased, Alternating current of the same nominal voltage is possibly more dangerous than direct current. Experience has taught us that both will cause death, and that if the fatalities from this source are to be kept low, certain precautions in the guarding of circuits must be observed.

Feb 1, 1929

By Richard V. Ageton

"Everyone admits that there are more accidents in metal mines than there should be but there is much difference of opinion as to the causes of accidents, whether avoidable or unavoidable, and the amount of responsibility attaching to the miner and the mine operator, respectively. However, it seems that one of the main reasons why there are so many accidents, is that there is so little general knowledge regarding their causes and costs. Some information regarding the costs and causes of metal-mine accidents is presented in this paper.The data contained were obtained from a study of the complete accident and medical reports of two large metal-mining companies, which carry their own insurance. Path maintain hospitals with competent medical attendants. One of these companies also maintains a very efficient safety bureau, consisting of a safety engineer, with two assistants who work in connection with the medical department, and with the safety committee made up from among the miners themselves.Daring the year of 1920, ""A"" Company employed approximately 900 men, and these men worked more than 270,000 shifts. There were 373 minor and major injuries, among these 900 men, hence assuming that each injured man was hurt cut once, 41 per cent of the men who worked in this mine received some kind of time-losing injury during the year. On account of these injuries the injured men lost 3731 shifts, and thus the time lost due to injuries amounted to approximately 1.4 per cent of the total number of shifts worked,"

Oct 1, 1923

By E. J. Gleim

During the past 10 years the Bureau of Mines has had a broad experience in the tasting and inspection of electric motors for gaol-cutting machines, cowl drills, storage-battery locomotives and other equipment Which is used in mines where explosive mixtures of methane and air may be encountered. From this experience the Bureau's engineers have reached the conclusion that the most satisfactory method of protecting a motor so as to prevent any sparks resulting from rough commutator, loose contacts or short-circuits in it, from igniting he surrounding atmosphere, is to totally inclose the motor with a substantial casing; having flanged joints. These joints should be metal-to-metal contact so that the shortest path from the interior to the exterior Of the casing is not less than one inch in length. On account of this experience with mining machinery, the Bureau has been asked whether an equal or loss degree of protection would be sufficient for motors for service in or about places such as refineries, gasoline filling stations, cleaning establishments and pumping stations, or in any place where there is liklihood of explosive mixtures of gasoline or naphtha vapors and air accumulating.

Jan 1, 1922

By W. D. Ryan

Industry must be made to realize that "Safety First" means just that - safety first. The miner must realize that safety first takes precedence over earnings. The employer must realize that safety is the first consideration, and is not to be subordinated to profit-making. Neither employee nor employer is justified in adopting the principle of safety first with reservations; that is they will practice safety first only so long as they think that it does not interfere with earnings or profits. This paper proposes to demonstrate that suberdinating safety to possible profit is short-sighted and that over an ex- tended period of time it dres not result in increased profits or earnings. An employee through disregard of safe practice may receive an injury that will cause him a loss of earnings if, indeed, he is net killed or permanently in- capacitated. If permanently incapacitated any compensation he may receive is very likely to be wholly inadequate as compared with probable earnings if the accident had not cccurred. The employer, upon his part, will find that the burden of compensating his injured employse will far exceed the outlay of money necessary to maintain a reasonable program of safety in his mine or plant. The mine foreman is one of the most important factors in the matter of mine safety. A vigilant and competent mine foreman, once he has established the confidence of the employees in his ability as a foreman, can be of invalu- able assistance in promoting mine safety, for through him and his assistants the employees may be made to cooperate. Every employer should remember, then, that the soluction of the foremen and their assistants is one of the most important matters connected with the work of establishing the maximum amount of safety in his mine. Everyone connected with the mining industry must be made to realize that there is to be no back-sliding and no let-up in safety work; that no matter how dry and tedious the routine may seem it is absolutely essential and justi- fied for both humanitarian and economical reasons. Efficient safety effort pays dividends in actual cash to both employer and employee. About 50 per cent of underground accidents in coal mines take place at the working face where the miners dig and load the coal. Approximately 17 per cent of coal-mine fatal accidents are the result of underground haulage. Face and haulage accidents can and will be reduced materially if the individual miner takes all precautions necessary to protect himself and if the management

Jun 1, 1930

Improve the dust-control effectiveness of the Rotoclone1 dry-dust collection systems used on surface coal mine drills.

Jan 1, 1994

By Howard E. Parkinson

Since 1969, the Department of Interior, Bureau of Mines, has carried out communications research. Research has been directed toward developing emergency and nonemergency mine communications. This paper gives an overview of the progress made in the last two years. Particular emphasis is given to the overall program, noise and signal measurements, systems studies, guidelines, products, and demonstrations now being carried on in operating mines.

By Garrett R. Hyde

Sintered yttria and sintered dysprosia can be used to make single-component thermistors having typical thermistor geometries and operable in the temperature range 500° to 1,200° C. However, at these temperatures, instability of platinum electrodes can contribute a slight aging effect if the thermistor is kept near 1,200° C for long periods. Typical characteristics at 500° C for an yttria disk thermistor 12 mm in diameter and 2 mm thick are a resistance of 12.4 megohms and a temperature coefficient of resistance of -3.8 percent per degree C. Typical characteristics at 500° C for a dysprosia thermistor of the same dimensions are a resistance of 1.84 kohms and a temperature coefficient of resistance of -1.6 percent per degree C.

Jan 1, 1970

By Ronald D. Hill, Elmore C. Grim

The goal of blasting is to get maximum fragmentation of the consolidated material in the overburden with optimum drilling and blasting cost. The amount of fragmentation required is determined by the stripping unit to be used In overburden removal. Many coal seams must also be broken by blasting; this is conducted before coal removal. There are environmental factors as well as due regard for public safety, health, and welfare that must be considered in choosing the blasting plan. The blasting plan should be made during preplanning and is based on data from the overburden cores. Analysis of the data will help In determining the kind of drilling equipment and bit types that will be needed for overburden preparation.

Jan 1, 1974

By Nicholas T. Zilka

One mineral deposit in the Golden Trout Wilderness has potential. The currently producing Pine Tree Mine on the Little Kern River has an estimated 120,000 tons (109,000 t) each of indicated and inferred reserves averaging 0.77 percent tungsten trioxide. No apparent potential exists for base or precious metal or other mineral deposits. INTRODUCTION The Golden Trout Wilderness, established by Congress in 1978 under Public Law 95-237, encompasses 240,000 acres (97,000 ha) of conifer-forested, rolling, upland plateau at the headwaters of the Kern River in Inyo and Sequoia National Forests (fig. 1). Abundant streams locally contain Golden Trout, namesake of the area. Major roads serve the area to the west and east of the Wilderness; access is poor to the north and south.

Jan 1, 1982

By C. M. Mason

Mechanical mining produces large quantities of very fine coal dust called float dust. The associated increase in hazard requires a reexamination of the Bureau of Mines method of evaluating the incendivity of explosives in coal dust-gas-air mixtures. A technique recently developed by Bureau of Mines laboratories for evaluating the incendivity of explosives in coal dust-air mixtures was applied, with modifications, to coal dust-air-natural gas mixtures. A series of permissible explosives were evaluated by this modified technique. Results indicate that the modified technique could be the basis of a more discriminatory procedure than that presently in use.

Jan 1, 1968

By Fred N. Kissell

In This Chapter [Early indicators of a gas problem How the methane hazard is reduced Ventilation principles for gassy tunnels Monitoring for gas Eliminating ignition sources and The all-important human factors component] This chapter gives guidelines for preventing methane gas explosions during tunnel construction. Emphasis is placed on assessing the hazard potential, on ventilation principles, and on monitoring for gas. The chapter also emphasizes the importance of human factors in reducing explosion risk. Ensuring safe conditions is much more than just good engineering design. It also involves the every-day vigilance of those working underground. This does not imply that the engineering design can be ignored, only that the job of providing safe conditions has just begun with design. EARLY INDICATORS OF A GAS PROBLEM For the engineer planning a tunnel project, reliable early indicators of methane are scarce. How-ever, the local geology can often provide some information.2 Carbonaceous rocks and tar sands are a likely methane source. Gas is also a distinct possibility if it is known to be present else-where in the same sequence of geologic formations. Swampy areas, sewerage systems, and landfills are also candidates because the decomposition of organic materials produces methane. The gas in a tunnel can originate in the strata being excavated, or it can migrate a considerable distance from adjacent strata. Test borings at the project site can also serve as initial indicators of gas. Methane has no odor, but may be emitted along with gases that do. If gas is emitted from the borehole, a sample may be collected by inserting a tube into the hole as far as possible and pumping the gas out. The gas sample should be collected in a sampling bag or canister for later analysis by a chemical laboratory.3

Jan 6, 2006