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By Charlie Wyche

In 1980, gold, silver, and pit and quarry construction materials were the principal minerals produced in the Dominion of Fiji. The combined value of these minerals totaled some $7.2 million,2 over 85% of all mineral production, Production of cement, sand and gravel, and quarry products continued to increase, but gold and silver production from Fiji's only operating mine declined slightly from the previous year's level. Mineral exploration has been carried out by U.S., Australian, British, Canadian, West German, and South African companies since the early 1960's, and a high level of activity was maintained throughout 1980. At the end of 1980, some 40 mineral prospecting licenses covering over 4,300 square kilometers were in force, and 19 applications were under consideration by the Mineral Resources Department. Total expenditures by mining companies on land base projects exceeded $6 million in 1980.

Jan 1, 1982

By Joseph D. Davis

Selection of a suitable coal or coals for the manufacture of coke of desired quality with due consideration of the purpose for which the coke is intended requires careful thought, and often it will pay to go to consider able expense in testing such coals as may be available. In general it will always be possible to obtain a satisfactory coal or blend of coals for the particular purpose in view, but in some places the cost of transportation would be prohibitive. It may then be necessary to consider a coal or coals inferior in grade, rank, or both. At times, in fact, only one inferior coal may be available, when the problem becomes mainly one of selecting equipment and operating conditions best adapted to that coal, keeping in mind that the end product of the plant must compete with the imported product in the market the plant will serve. This applies particularly to new projects for which it is necessary to build a plant and start with a clean slate, so to speak. However, it will pay every coke-plant manager to employ a force to continually test the coals used and the coke produced to make sure that the quality is not changing appreciably. Furthermore, if the supply of coals used becomes exhausted it will be necessary to use other coals. Continual testing is particularly necessary at plants using borderline coals or blends, where slight changes in the composition or in operation of the ovens may render them dangerously expanding. In this connection it should be stated that control in the newer coke plants is considerably easier than for those built a decade or so ago, consequently in the new ovens a given operating program can be maintained more precisely. This point is important, because one of the main requirements of the coke user is uniformity in both physical and chemical characteristics. For example, any appreciable changes in the quality of coke delivered to the blast?-furnace operator will involve changes in operation if the best results are to be obtained. Such changes are expensive usually they take considerable time and involve production of inferior iron.

Jan 1, 1942

By Wilbur I. Duvall

This report presents experimental data on crater formation in four rock types. From an analysis of these data a general theory of rock breakage by explosives is deduced. This theory accounts for most of the rock breakage and other phenomena that occur when a concentrated charge is detonated in a drill hole near a free surface. From instrumented crater tests and high-speed motion pictures of the explosions, various experimental checks on the deduced theory of rock breakage are made. The general mechanism of rock breakage by explosives as described in this report is outlined briefly below. The detonation of the explosive charge creates a high gas pressure in the charge hole, which in turn generates a compressive strain pulse in the surrounding rock. This compressive strain pulse travels outward in all directions from the charge hole. Near the charge hole the amplitude of this strain pulse is sufficient to cause crushing of the rock. However, as the strain pulse travels outward its amplitude decays rapidly until no further crushing of the rock is possible. The compressive strain pulse continues to travel outward until it is reflected by a free surface. Upon reflection the compressive strain pulse becomes a tensile strain pulse. As the strength of rock in tension is much less than in compression, the reflected tensile strain pulse is able to break the rock in tension, progressing from the free surface back toward the shot point. In other words, the rock is pulled apart, not pushed apart.

Jan 1, 1957

By W. M. Deaton

The formation of gas hydrates in natural-gas pipe lines depends on temperature and pressure conditions in the lines as well as on the presence of condensed water. The operating pressure in a pipe line may be determined easily and usually is available from the records of operation, but the temperature seldom is known. In cooperation with the American Gas Association, the Bureau of Mines, in its investigation of gas hydrates, conducted a pipe-line-temperature survey and studied underground temperatures at depths at which pipe lines ordinarily are buried and the relationship of these temperatures to prevailing atmospheric conditions. A similar but mere limited study of this type was conducted by engineers of the Bureau of Mines a number of yours ago.4/ A summary of the earlier findings was included in a general report by the Bureau on the flew of natural gas through high-pressure transmission lines.5/ In the present study, data on temperature variations were obtained at several places widely separated geographically. This information should assist pipe-line engineers in designing and operating natural-gas pipe lines.

Jan 1, 1941

By Thomas J. Peters

In 1985, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied a 17,320-acre portion of the 52,143-acre Little High Rock Canyon Wilderness Study Area (CA-020-913/NV-020-008) in order to evaluate its identified mineral resources. The study area is located in Humboldt and Washoe Counties, NV, about 42 miles north from Gerlach. Three areas of epithermal alteration, similar to alteration associated with disseminated gold deposits, were found in the study area. One of the areas occurs along a northeast-trending structural lineament. Southwest of the study area two gold prospects undergoing active exploration, as well JS a gold deposit being prepared for production, occur along the same lineament. The Bureau of Mines examination, however, did not find evidence for gold resources in the study area.

Jan 1, 1987

By R. F. Droullard

The Bureau of Mines has used gross alpha and gross beta detectors to continuously measure radiation working levels for a number of years. During this time, improvements have been made in the design and performance of continuous working-level (CWL) detectors. This report discusses the improved designs and some of the operating principles and applications of CWL detectors in the measurement of radon daughter products in mines and dwellings.

Jan 1, 1985

By Louis Schaffer

The objectives of the research were to determine whether a model health and safety program could be defined in terms which would enable its application to mines of all types, and, if such a model program could be defined, to determine through evaluations in two mining companies whether it would achieve measurable improvements. Volume 1 describes the model, how it was applied in the field and how it was evaluated. This, Volume 2, describes the literature and field research that preceded the model definition.

Jan 1, 1983

By O. C. Blade

Studies on more efficient utilization of petroleum have been made for 50 years by the Bureau of Mines. As part of this work, the Bureau has analyzed thousands of samples of crude oil by its standardized routine method, and many of these analyses have been published, sometimes in special compilations, other times in connection with reports of research on petroleum. This report is a finding index for all analyses published from 1921 to 1959, and brings up to date the information in Information Circular 7470 3 and in the appendix of Bulletin 490.4 The routine method of analysis and the equipment originally were described in a report by Dean and associates. 5 This report has long been out of print, but Bulletin 490, bringing the procedure and its modifications to date, was published in 1951. 6 Briefly, the procedure consists of testing, by standard methods, small samples of a crude oil for gravity, sulfur, color, viscosity, pour point, and (more recently) nitrogen; and, by a standardized procedure, distilling a portion of the crude oil and determining certain properties on the separated fractions and residuum. Careful records are made during the procedure, and the distillation data obtained are used to compute the approximate amounts of products present in the sample--such as percentages of gasoline, kerosine, gas oil, and lubricants. The principal data and results are recorded on a standard analytical report form. An analysis of a sample of crude oil from a recently developed field is shown in table 1. Compilations of these analyses, sometimes in tabular form and usually for specific geographic areas, are published from time to time. Analyses often are included in connection with other studies, such as engineering field reports.

Jan 1, 1959

By W. D. Striffler

Land disturbed by surface mining in Colorado and other western states has increased substantially over the past several years and is likely to increase even more in the future. This study was initiated to provide basic information on hydrologic and erosional characteristics of regraded coal spoils in Colorado as an aid for planning future reclamation activities. Eleven of twenty-one surface mines licensed in Colorado were sampled during the summer of 1980 and 1981. Mines not sampled included mines which had not progressed to the point that reclamation had begun, and mines where operators denied permission to sample. All coal regions were sampled with the exception of the San Juan Coal Field. Physical and hydrologic characteristics of regraded coal spoils in Colorado were determined using standard field and laboratory procedures. Field sampling included characterization of sites (slope, vegetation density, proportion of surface rock, bare soil, etc.) and infiltration measurements using a l-meter square drop former raining on a 1/2 square meter rectangular plot frame. Core samples collected in the field were analyzed for saturated hydraulic conductivity, bulk density, organic matter, moisture retention and texture. The erosion potential of each site was determined using the Universal Soil Loss Equation (USLE). Results of the sampling indicate that infiltration rates vary widely both within and between sites. However, definite trends with respect to coal fields are apparent. For example, the Green River (Yampa) coal region had a wide range of sampled infiltration rates (1.2 to 5.1 cm/hr). However, most of the sites clustered towards the low end of the range. The North Park (Marr Strip) also was rated at the low end of the infiltration range (2.0 to 3.0 cm/hr). Average infiltration rates for the Canon City and Uinta Coal Regions were at the high end of the range (4.9 to 5.5 cm/hr). Multiple correlation analysis of infiltration rates vs. site characteristics showed that infiltration rates were most closely correlated with the depth of wetting, the amount of mulch cover, and site slope. The depth of wetting was highly correlated with the depth of the topsoil and the bulk density of the spoil. In general, the topsoil at all sites appeared to be highly permeable to water intake but once saturated, subsequent infiltration depended upon characteristics of the underlying spoil. Vegetation cover affected infiltration on individual mine sites but was not as pronounced as topsoil characteristics or mulch. Erodibility of topsoil and spoils, as determined by Wischmeier's "K" factor, ranged from 1.34 to 0.56 tonnes/ha. (topsoil) and 1.25 to 0.66 tonnes/ha. (spoils). Definite trends in erodibility are evident. The Green River (Yampa) Coal Region displayed consistently higher erodibilities (1.34 to 0.75 tonnes/ha.) than other coal fields (0.72 to 0.56 tonnes/ha). Lowest erodibilities were observed in the Uinta, North Park, and Raton Mesa Coal Regions (0.56 to 0.62 tonnes/ha). Erodibilities of underlying spoils showed similar trends as the topsoils. Erosion potential (the product of soil erodibility and rainfall erosivity) was detennined using calculated ?K? factors and rainfall erosivities (R) taken from Clyde (1976). Results show that the Delagua coal field, Raton Mesa Coal Region had the greatest erosion potential due to the high rainfall energies in the region, while the North Park and Uinta Coal Regions had the lowest potential erosion.

Jan 1, 1981

By J. B. Zink

The Bureau of Mines developed a spectrochemical method to determine six constituents in coal ash in the following concentration ranges: silica 9 to 63 percent, alumina 7.5 to 35 percent, ferric oxide 2 to 30 percent, calcium oxide 1 to 29 percent, magnesium oxide 0.5 to 6 percent, and titanium oxide 0.5 to 4 percent. Samples of coal ash are fused with a mixture of lithium tetraborate and vanadium pentoxide. The resulting beads are crushed, mixed with powdered graphite, and briquetted. The pellets are analyzed spectrographically, using controlled high-voltage spark excitation. Vanadium serves as the internal standard. Effects due to matrix variations are minimized by fusion with lithium tetraborate. Intensity ratios of selected analytical lines are determined photometrically, Concentrations are read from analytical curves, prepared from synthetic standards, relating log intensity ratios to log concentration. A combustion procedure is used to determine sulfur tri-oxide. The method is most useful when large numbers of coal ashes must be analyzed but a high degree of accuracy is not essential.

Jan 1, 1967

By H. C. Fuller, E. L. Anderson, F. S. Wartman, M. A. Cook

"This paper gives an account of the production of ductile-grade titanium powder in 100-pound batches by reduction of purified titanic chloride with magnesium, followed by grinding, leaching, and magnetic separation of the reaction product. Apparatus, technique, and methods of controlling product quality are described, and some data on operating costs are given.Although man has been aware of the existence of the element titanium for over 150 years, only recently has the metal itself been available in a form pure enough, particularly with reference to absorbed gases, to allow an estimate of its physical properties. In comparison with mild steel, the tensile strength of titanium is about the same, the resistance to atmospheric corrosion greater, and the specific gravity much less.These properties suggest the usefulness of titanium as a structural material for applications requiring resistance to atmospheric attack and a good strength-weight ratio. Although known reserves of titanium, high-grade enough to be useful at present are not sufficiently extensive to predicate that titanium might supplant iron, aluminum, and magnesium for structural purposes, the reserves are large enough to make its use as a structural material quite feasible in certain fields in which its unique properties are required.As a result of these considerations, the Bureau of Mines station at Tucson initiated an, investigation into the technology of titanium in 1938. First, a critical survey and small-scale trial of virtually all suggested methods7/ for producing the metal was made. The method devised by Kroll8/ seemed best adapted as a source of metallic titanium for, although the purity of the product was not as high as that of products from some other processes, it seemed that modifications in technique necessary for larger-scale production could be made more easily.Essentially, in applying the Kroll process, titanium tetrachloride was reduced to metallic titanium by adding the chloride slowly to molten magnesium contained in a molybdenum-lined iron reaction chamber filled with a protective atmosphere of argon. After reduction to the state of completion desired, the reduction mass and chamber were allowed to cool. Then the chamber was opened, and the reaction mass, consisting of titanium, magnesium chloride, and some unused magnesium, was removed by suitable means. Most of the magnesium chloride and metallic magnesium were removed by leaching in dilute hydrochloric acid. The leached sponge was then ground wet in a ball mill, releached in strong acid, and dried Removal of free iron by magnetic separation completed the production process.Development of the Kroll process by the Bureau was undertaken first at the station at Salt Lake City, in 1942 and the amount formed per run was increased in several steps from a few grams to pounds.9/ In addition to increasing the size of batch over that used by Kroll, the technique was simplified somewhat by the use of unlined reaction vessels."

Aug 1, 1949

By John C. Edwards

A computer program, developed for the Bureau of Mines under contract, predicts in a quasi-steady-state approximation the ventilation and contaminant concentrations and temperatures when a fire occurs in a multi-level mine. For periods of time in which there is no significant change in the ventilation, yet a fire is producing fumes, a real-time fume concentration throughout the mine is calculated. Multiple and time-variable contaminant sources can be simulated. Recirculation paths that can develop provide a mechanism for increasing the fume concentration in the mine network and are identified by the computer program. This report contains a listing of the Fortran computer program as well as the required format of the input data. Two examples are provided of the real-time spread of smoke from a fuel-rich fire throughout a multilevel mine. The first example considers an operational exhaust fan as well as a booster fan. The second example evaluates the real-time smoke spread following a failure in the exhaust fan; recirculation occurs in this latter case.

Jan 1, 1982

By Joseph Grumer

An instrumented spherical vessel has been used for many years to study laminar combustion waves. Concurrent measurements of flame speed and pressure-rise rates have led to evaluations of burning velocities, the pressure dependence of the burning velocity, and the expansion ratios of the gases passing through the combustion wave. For the most part, these studies have involved flames initially at atmospheric or subatmospheric pressure. The old spherical vessel used by the Bureau of Mines was not designed for use at elevated pressures. Moreover, being made of wrought iron, it was susceptible enough to corrosion to prohibit its use with many combustible mixtures that figure in industrial research. In mid-1956, under sponsorship of the Office of Naval Research, the Bureau undertook the development of a stainless steel spherical vessel capable of withstanding explosions of gaseous mixtures at initial pressures as high as 20 atm. and initial temperatures as high as 250° C. The design called for a double array (cross) of closely spaced small windows for observation of the flame as it traversed the vessel and a piezoelectric transducer to measure concurrently pressure-rise rates. Because no commercial contractor was willing to bid on the construction of such a vessel, it was built at the Bureau's Bruceton machine shop.7

Jan 1, 1961

By F. W. Lee

This paper purposes to outline briefly results of seismic measurements made in the vicinity of blasts in a mine and in open-quarry operations. It endeavors to examine the amplitude and frequency of such vibrations as influenced by the loading, geology, and distance from the source and includes comments on factors that may index the destructiveness of a vibration and a method for measuring the stresses produced. There seems to be no simple mathematical analysis of the transmission of seismic energy through the ground, and experimental observations are at present most feasible. SEISMOLOGIC INSTRUMENTS Instruments developed by the Bureau of Mines for recording ground vibrations from quarry blasting comprise a new type of seismometer, oscillators, and a recording oscillograph. The seismometers respond to vibrations reaching them through the earth and transmit their characteristics by electric current to the oscilloglaph, where they are recorded by a beam of light on a moving strip of sensitized photographic paper. The seismometers are so constructed that their sensitivity to earth vibration can be controlled, thus keeping the amplitude of the recorded wave within bounds on the paper. Each instrument has been calibrated against vibrations of known intensity and frequency so that correction factors are known for the idiosyncracies of each unit. Moreover, each seismometer is calibrated in the field for its particular sensitivity setting at each blast. By these controls the actual movement of the earth due to vibrations of one ten-thousandth of an inch can be accurately measured.

Jan 1, 1936

By John A. Breslin

The Bureau of Mines measured respirable dust in coal mines by means of multiple dust samplers worn by persons moving about the mines. The measurements were made primarily to evaluate the effectiveness of certain dust-control techniques; however, for this report, the data have been analyzed to determine the precision of the personal dust-sampling measurements. A total of 68 sets of measurements were available from multiple personal samplers. The measured dust masses were less than 1.0 mg because the sampling times were short. The coefficient of variation calculated from these data was 18.5 pct, compared with coefficients of variation ranging from about 10 to 30 pct, which were calculated from the most precise and extensive data available for fixed-point dust measurements made in coal mines. From this comparison, it is concluded that dust samplers worn by personnel are as precise as fixed-point samplers in measuring respirabe coal dust; the wearing of the samplers by someone moving about a mine does not contribute significantly to the variation in measurements made with these instruments.

Jan 1, 1983

By Frank B. Fulkerson

A study was made of scrap iron and steel in the South Central States in order to determine trends in processing, shipment, and consumption of this important commodity. These data were derived in part from statistical sources and in part by visits to scrap yards and steel mills. Trends in the industry were reviewed. Dealers in 1963 supplied 1.8 million tons of iron and steel scrap to steel mills and foundries in the south-central area, compared with 2.1 million tons in 1955. Most of the scrap was processed and shipped within 200 to 300 miles of consuming centers. Exports provide a principal outlet for dealers along the gulf coast. Most of the scrap that fills these orders is loaded onto freight cars at yards in Texas and Louisiana and -is shipped to ports for direct transfer from railroad car to ship. The tonnage exported varies greatly from year to year. The largest scrap operations are in or near large cities which are heavy scrap generating areas, steel mill sites, or port cities for export of scrap. A tentative analysis indicates that the short-run supply of prepared scrap is inelastic to price changes; therefore, buyers probably arc in a strong bargaining position at times of declining demand. One technological development in the iron and steel scrap industry is the use of large presses which can take complete automobiles with frames, wheels, springs, and other heavy parts still intact and reduce them to bundles. At Houston, Tex., and Kansas City, Mo., shredding plants are in operation that reduce car bodies and other light scrap into flat pieces 4 to 6 inches in size.

Jan 1, 1966

By F. W. Lee

This paper purposes to outline briefly results of seismic measurements made in the vicinity of blasts in a mine and in open-quarry operations. It endeavors to examine the amplitude and frequency of such vibrations as influenced by the loading, geology, and distance from the source and includes comments on factors that may index the destructiveness of a vibration and a method for measuring the stresses produced. There seems to be no simple mathematical analysis of the transmission of seismic energy through the ground, and experimental observations are at present most feasible. SEISMOLOGIC INSTRUMENTS Instruments developed by the Bureau of Mines for recording ground vibrations from quarry blasting comprise a new type of seismometer, oscillators, and a recording oscillograph. The seismometers respond to vibrations reaching them through the earth and transmit their characteristics by electric current to the oscillograph, where they are recorded by a beam of light on a moving strip of sensitized photographic paper. The seismometers are so constructed that their sensitivity to earth vibration can be controlled, thus keeping the amplitude of the recorded wave within bounds on the paper. Each instrument has been calibrated against vibrations of known intensity and frequency so that correction factors are known for the idiosyncracies of each unit. Moreover, each seismometer is calibrated in the field for its particular sensitivity setting at each blast. By these controls the actual movement of the earth due to vibrations of one ten-thousandth of an inch can be accurately measured.

Jan 1, 1936

By Frank Parrish

History and performance data of 17 water-injection projects in Cooke and Grayson Counties in north Texas are presented for the purpose of studying and comparing operating practices and oil-recovery techniques. Water is injected into Strawn and Canyon sands of Pennsylvanian age. The principal formation flooded is the Strawn, which ranges in depth from 725 to 6,900 ft in the projects covered. Estimated ultimate recoveries range as follows: Primary, 22 to 494 bbl per acre ft; and secondary; 63 to 296 bbl per acre ft. These figures represent the following percentages of original oil in place: Primary, 10 to 46 pct; and secondary, 8 to 23 pct. Shallower projects; 725 to 1,500 ft in depth, had higher average primary and secondary recoveries than did deeper projects. Crude-oil gravity, which ranges from 20° to 45° API, was not relatable to yield of secondary recovery oil. Analysis of the data indicates that five-spot injection patterns will yield the highest percentage of oil remaining at start of flooding; that is, 28.8 pct for five-spot injection patterns, compared with 20.8 pct for line-drive patterns and 11.6 pct for random patterns. Waterflooding in this area appears to be very successful. Secondary recoveries of most projects are expected to nearly equal primary recoveries.

Jan 1, 1963

By Edward W. Ames

"The Jewell tunnel property, situated 3/miles north of Garfield, Chaffee County, Colo., was examined by an engineer3 of the Bureau of Mines in June 1943. Field work began September 16, 1944, but was recessed from December 26, 1944, to gay 15, 1945, because of heavy snows, and was suspended July 12, 1945, when rehabilitation of the New York tunnel workings was completed to the point desired.In its program of exploration of Mineral deposits, the Bureau of Lines has as its promary objective the more effective utilization of our mineral resources, to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as seen .as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples of ore and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.For their supervision of the project and their help in revising the report, particular acknowledgment is due Wm. P. Huleatt, district engineer, Denver, Colo., and Paul T. Allsman, chief, Salt Lake City Division, Mining Branch.The property is situated in secs. 15 and 22, T. 40 N., R. 6 E., N.R.F.M. Salida, the county seat, is on the main line of the Denver & Rio Grande Western Railroad. The property is reached from Salida by following U. S. Highway 50 westward for 18 miles to the village of Garfield, near Monarch Pass, then northward for 3 miles by a very steep mine-access road up Taylor Gulch (fig. 1).The highway to Garfield is accessible throughout the year, but the access road from Garfield is generally impassable from December until June because of snow."

Sep 1, 1946

By Donald F. Reed

In the latter half of 1948 the Bureau of Mines investigated the Magnet Cove Rutile Co.'s prerty in northern Hot Spring County, Ark. This work was supplemental to the work done by the Bureau on the same property in 1945.2/ It was undertaken for the purpose of investigating the extent of the ore body toward the south and west and at depth and to obtain representative samples of the ore for metallurgical tests. For the latter purpose, the samples were so taken as to minimize alteration of the physical characteristics of the ore, these characteristics being determining factors in working out processes of bencficiation. During the investigation, 27 holes were drilled, 10 with a diamond-coro drill end 17 with churn-drill rigs using a Baker standard cable-tool core barrel. Drilling developed an extension of the ore deposit westward from the previously mined area but did not disclose the full depth of mineralization. Metallurgical tests to determine methods of beneficiating the ore and utilizing the resultant products are now in progress.

Dec 1, 1949