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By Clarence O. Babcock

In this report, the Bureau of Mines presents a method for reducing the complexity of designing room-and-pillar mining systems by treating them as anisotropic soft inclusions in the surrounding ore or host rock. Theoretical models were derived for the calculation of the effective Young's moduli for these systems. The predicted behavior of the plate-type elements used in these models agreed well with test results from 21 plates each with 49 holes spaced on a 7 X 7 Cartesian grid. The plates behaved as anisotropic solids, the effective Young's moduli of which could be predicted from the scaled hole size and spacing. Actual hole shape was insignificant. The effective Young's moduli for simple mining systems are calculated in sample problems. This approach should provide information about field stress in the mining region and the stress distribution in the surrounding ore or host rock when the actual mining configuration is replaced by an anisotropic inclusion in a finite element analysis. The field stress within the inclusion can then be applied to the actual opening shape to determine the stress distribution within the mining region.

Jan 1, 1970

By H. Dale Nichols

[The growing importance of the Sundence (Jurassic) formation an a source of oil, in the Rocky Mountain area has prompted the making of a series of porosity determinations of core samples collected. from the reservoir sands of the Lance Creek oil field, Niobrara. County, Wyo. These analyses are preliminary to a stud of fluid and energy relations in the Basal Sundance reservoir of that field, and the determinations of porosity will be used in subsequent studies requiring, calculations of the volumetric capacity of the reservoir and estimation of the reserves of oil and gas. However, the porosity characteristics an of the Sundance sands in the Lance Creek field are factory that affect the solution of many current practical problems of development and operation. Primarily for that reason but also because it is recognized that porosity values of different oil-production sands are of widespread interest throughout the industry, the results of the initial work have been presented in tabular and graphic form with no attempt to evaluate their significance as they relate to the production history of the field.]

Jan 1, 1938

By N. E. Hanna

To be approved for use in underground coal mines in the United States, explosives and blasting devices must pass certain safety tests prescribed by the Federal Bureau of Mines. These tests are described in Schedule 1-G4/ (explosives) and Schedule 26A5/ (blasting devices). An explosive or blasting device that passes the appropriate tests is placed on the active permissible list. As this list is subject to continuous revision, it has been the practice of the Bureau of Mines to publish periodically the names of explosives and blasting devices that have been added to the active list, as well as those that have been transferred to the inactive list; changes in brand names also are reported. The present circular gives all explosives and blasting devices on the active permissible list as of December 31, 1957, and shows all changes, additions, and transfers in that list between December 31, 1951,6/ and December 31, 1957.

Jan 1, 1958

By W. H. Coghill, F. D. DeVaney

"Introduction Numerous investigators have studied grinding. Each has contributed his bit to a literature that is difficult to correlate. Too many of the results have been transformed into curves with no many ""inflection points"" and ""counterflexures"" that they obscure the issue.Some of the investigators have neglected the very essence of the problem, namely, the power and the amount of material to which a known amount of work was applied. The purpose of this paper is to show the ease with which results can be interpreted when these quantities are duly recognized. Some grinding tests will be given for illustration.Grinding studies are of two kinds: (1) Study of the character of the ore and (2) study of the performance of the machines. Several ores may be crushed by a given machine, or several machines may be used on a given ore. The illustrations given in this report cover both objectives.Grindability Characteristics When the ores are being studied the information sought is grindability characteristics (grain-size distribution) and the grindability (work required to produce new surface) of a group of ores.When the study is of the machines, several machines are used for a given ore or given types of ores, and the grinding performances of the machines are compared by a grain-size study.Table 1 gives the grindability characteristics and grindability of six substances, one of which is coal. The substances are arranged from left to right in progressing order of tons per horsepower-hour. Curves and graphs are not needed for elucidation. The secret of the ease of interpretation is the order mentioned and the similarity of the sizing analyses. Power records must be complete in grinding studies.The grinding device was a ball, plunger, and mortar called the drop weight.' It may be used to advantage when the amount of material to be tested is too small for the orthodox machines.The upper part of table 1 shows the grindability characteristics by the cumulative-sizing analyses. Note how closely the percentage weights agree for a given sieve size. The lower part shows the grindability in terms defined elsewhere. The present paper should be read in conjunction with that paper."

Jun 1, 1934

By M. J. Ferrante

The standard enthalpy of formation, low-temperature heat capacities, and enthalpy increments above 298 K were determined by the Federal Bureau of Mines for synthetic dawsonite [NaA1C03(OH)21. The enthalpy of formation was determined by hydrochloric acid solution calorimetry, with the result ?Hf°298 = -469.4±0.7 kcal/mole. The low-temperature heat capacities were determined from 6 to 307 K by adiabatic calorimetry. Tabulated are low-temperature values of Cp°, S°, and H.-Ho° from 3 to 298 K. The derived entropy at 298 K is S298 = 31.55±0.3 cal/deg mole. Enthalpy increments above 298 K were obtained by copper-block drop calorimetry. Tabular data of Cp°, S°, H°-H°298, -(G°-H°298)/T, ?Hf°, ?Gf°, and log Kf are given from 298 to 477 K. Enthalpies and Gibbs energies of decomposition are also reported.

Jan 1, 1976

By R. V. Ramani, R. Bhaskar

"The control of respirable dust in mines has been given paramount importance due to the health and safety implications associated with fine dust. The understanding of the temporal and spatial behavior of dust has been recognized as essential for increasing the efficiencies of the existing control techniques and for developing new control strategies. Mining-related studies in this area are, in general, limited. They are also mostly experimental. Some mathematical and computer analyses have been attempted. In this paper, first a review of the mathematical studies performed in the last three decades in this area is presented. Second, a mathematical model for analyzing dust flow in mines is proposed. The model takes into account a number of factors affecting dust transport. It incorporates varying dust generation source strengths and dispersion, deposition, and coagulation of dust in mine airways. Finally, application areas for the model are discussed. A computer program based on the mathematical model has been developed. The program will output the dust concentration in the mine atmosphere as a function of time and distance from the source. The amount of dust deposited on the sides, roof, and floor of the airway is also determined.IntroductionAn airborne dust cloud is a complex system containing particles of varied size, density, shape and state of aggregation. The behavior of the particles is dependent on a number of complex physical mechanisms, often opposing in nature. The net interaction results in the ambient concentration. This size dependent behavior of particles contrasts with that of gases, an area quite widely studied.The term aerosol is used to describe clouds of microscopic and submicroscopic particles in air such as chemical smoke or particulate matter released from smoke stacks. An aerosol system can be regarded as an arbitrary element of volume filled with gas and suspended particles of possible highly variable physiochemical nature. The parameters that are used to describe an aerosol system include concentration, mass average velocity and particle mass and radius. In characterizing such systems, several assumptions are made. Among these is the assumption that particles are smooth, inert and rigid spheres. Again, for example, when the particles are in transport, the possibility of collision exists. As a result of the collision, the particles may coalesce to form larger particles. The probability of sticking is considered a known quantity (lady, 1970). In this paper, the application of the principles used in aerosol systems is explored for the study of the transport and deposition of fine coal dust in underground mines."

Jun 1, 1988

By E. Morrice, R. D. Smith

Thermal expansion and electrical resistance measurements were made on cerium metal from 4° to 300° K. The apparatus developed , including a specimen holder and a cryostat system , are described along with the experimental techniques used in obtaining the measurements . The total linear thermal expansion Data at of 99.83 weight - percent cerium metal between 4 ° K and room temperature was 4.24 percent . The resistivity at 4° K was 7.0 x 10-6 ohm- centimeter . 4° K indicate a fundamental relationship between residual resistivity and purity of cerium metal . The effects of annealing and repeated thermal cycling on resistivity were determined .

Jan 1, 1964

By C. T. Baroch

As part of a general program for investigating all phases of titanium production, argon was substituted for helium in the reduction step at the Bureau of Mines pilot plant, which employed a modification of the Kroll, or magnesium-reduction, process. Argon was substituted for helium in 108 of the 140 batches of sponge made during 1 month's reduction operations for July 1954. Argon was substituted for helium satisfactorily, with only slight modifications in technique. Metal quality, feed rate of TiC14, magnesium efficiency, and average production per batch were closely comparable with either gas. Argon runs were slightly more troublesome because of the formation of condensable chloride complexes, which tended to plug feed and vent lines and to entrap deposits of lower titanium chlorides on the reactor-pot lids. These lower chlorides were objection-able because they were pyrophoric and created obnoxious fumes when pots were opened. When feed and vent lines became plugged care was required in poking or unplugging these lines to prevent air from entering the reactor. These problems were relatively minor, and continued development of reactors and techniques for the use of argon should further minimize objectionable side reactions obtained when argon is used.

Jan 1, 1956

By D. R. Tesarik

Displacement and stress changes in cemented backfill and ore pillars at the Buick Mine, near Boss, MO, were monitored by engineers from the U.S. Bureau of Mines and The Doe Run Co., St Louis, MO. A test area in this room-and-pillar mine was backfilled to provide support when remnant ore pillars were mined. Objectives of this research were to evaluate the effect of backfill on mine stability, observe backfill conditions during pillar removal, and calibrate a numeric model to be used to design other areas of the mine. Relative vertical displacements in the backfill were measured with embedment strain gauges and vertical extensometers. Other types of instruments used were earth pressure cells (to identify loading trends in the backfill), borehole extensometers (to measure relative displacement changes in the mine roof and support pillars), and biaxial stressmeters (to measure stress changes in several support pillars and abutments). Two-and three-dimensional numeric codes were used to model the study area. With information from these codes and the installed instruments, two failed pillars were identified and rock mass properties were estimated.

Jan 1, 2010

By E. D. Gordner

Irrespira ble gutses issuing from the rock fofflb tions ere tJ source of expense ond danger in some metGLl mines. There is a great Variation in the compos i-· tion of such gdses and, os shown 'by recent sampling by the Bureau of ines, the gas rr;;,.y consi$t mostly ct carbon dioxide, (Rocle Strata Gtsses in the Mines of the East Tintic Mining District, by G. E. McElroy, Bu.retau of Mines Serial 2Z75) or f methone (Metruine in Ccalifornia C.old Mines, by B. 0. Picl-Q:lrd i:lnd !.. D. ("iordner, Bure, cf Mines Serial 2303), or nitrogen, sin the present instonce. A nl.liilber of unventilated rt:t.ises in some of the mine of l:l Neva&. district conuin «i'ccumulCltions of l;i hih-nitrogen gas the1t will not supi:ort life or combus­tion. The rdises ore in different geologiecil formations and in widely sep1:1rated. loecslities in the mining district. One ot" two ri::lises in the sme fc.rtr.ation may be full of the gos cand einother nec-r'by be t'ree ot· it. Lives have been lost t:lnd a number of men heave been overcome on enteing unvetilated rtsises in which their­respircable tss hcsd c1ccuni..1.l1::1ted between sldfts. Gener1:1lly, however, the gas see:ns to noozett from the .t'onrbtio:1 ond to ecc1: .. ,i.-1,;.1:.1te so slowly tMt its presence is not suspected t the tfr.1e, bu.t discovered. ed:'t&.c' the raise is t)band.oned. OcCE.isionelly 1 t issues from a ne•.,ly cut cre·tice or fissure under considerca ble pressure and in lar!?e enough '3.'16ntities to overcome or drive 011t men working in unventilated places.

Dec 1, 1922

By Louis C. Brichta

The rapid; depletion of' known high-grade ore deposits in the Tri -State lead-zinc district and the recognized need for the development of additional reserves led the Bureau of Mines to make preliminary examination of sites possibly adaptable to low-cost open-pit mining methods. Abandoned mines whose ore deposits were known to have occurred at shallow depths naturally presented favorable test points for the development of possible open-pit orebodies. The Lone Elm mine was in this category.

Jan 1, 1949

By N. A. Eilertsen, Rolf S. Paine

The Bureau of Mines studied the presplitting technique used for controlling overbreakage in the walls of a vertical shaft at the U.S. Army Corps of Engineers Littleville Dam project near Huntington, Mass. The periphery of the shaft, the dimensions of which were 16-1/2 feet wide by 21 feet long and 52 feet deep, was presplit (cracked) in the solid to a depth of 48 feet prior to full-depth sinking. Presplitting prevented overbreak in a fairly soft schist and provided sound self-supporting walls which required very little scaling.

Jan 1, 1965

By Thomas M. Nasiatka

This report briefly describes the present state of the art and the technological highlights of tunneling from its inception to the present. The discussion is concerned primarily with tunnels driven through relatively competent rock for mine development and various civil purposes. In addition to pinpointing the major technological breakthroughs in tunneling, this report indicates their general effect on the speed of tunneling. The tunneling speeds are based upon data from approximately 80 tunnels listed in the appendix. These data include length; cross section shape and dimension; type of rock; tunneling method; method of breaking, loading, and transporting the rock; average linear progress rate; and cost in values during the period of construction. Most of the tunnels described have diameters of 15 to 30 feet.

Jan 1, 1968

By B. W. Jong

The U.S. Bureau of Mines investigated anhydrous chlorination and caustic-acid leaching processes to recover Ni, Co, Mo, and W from waste hydroprocessing catalysts. In batch laboratory-scale equipment, the chlorination process extracted 61 to 99 pet of the metals. Final recovery was 65 to 99 pct. The caustic-acid leaching process extracted 81 to 98 pct of the metals. Final recovery was 36 to 99 pct. Chlorination processing included roasting, chlorination, hydrolysis of metal chlorides for recovering Mo or W, water leaching of Ni or Co from the spent charge, purification, and solvent extraction or precipitation of Ni or Co from the purified solutions. Caustic-acid leach processing included NaOH leaching, solvent extraction of Mo or W from the NaOH leach liquor, H2S04 leaching of the NaOH leach residue, purification, and solvent extraction or precipitation of Ni or Co from the purified solution. The estimated fixed capital cost for a commercial-scale plant processing 39,000 Ibid of waste Ni-Mo-AI catalyst was $8 million for the chlorination process and $9.6 million for the caustic-acid leaching process. The estimated operating cost was about $0.20 and $0.40 per pound of the waste catalyst, respectively, for the two processes.

Jan 1, 1989

By C. W. Huggins

The primary objective of this Bureau of Mines research was to measure the size distribution of respirable quartz collected at metal mines, nonmetal mines, and processing plants to select the best reference standard for use in quantifying quartz in mine and plant dust samples. The secondary objective was to size all the nonquartz particles collected at the same sites. Particle size measurements were made on 29 samples using a scanning electron microscope in the backscatter mode of operation, interfaced with an image analysis system. The Mine Safety and Health Administration, Denver, CO, provided the 29 samples, which were collected at mines and processing plants in 19 states. The accumulated particle size measurements indicate that NBS 1878, minus 5-f.lm Hin-U-Sil, and minus 5-f.lm Supersil would be preferred over Silver Bond B as reference standards for most quantitative determinations by X-ray diffraction and infrared spectrometry. The respirable dust samples collected at sand plants, however, would be better served by a new reference standard having a quartz particle size distribution of approximately 2.2 um, as none of the four existing reference standards matched closely with them. Commercially available NBS 1878 and minus 5-um Hin-U-Sil CQuid be used as reference standards for 28 of the 29 samples studied in this investigation.

Jan 1, 1986

By V. H. Gottschalk

Among the procedures developed by the Germans for providing the tonnage of iron powder needed to make rotating bands for artillery shells is the use of a ceramic tunnel kiln, not only for finishing the reduction of centrifugal powders but also for making so-called "brickyard sponge iron," which, after crushing and grinding, seems to yield a product suitable for powder-metallur- gical purposes. The final report issued jointly by the German Powder-Metallurgical Society (DPG) and the Chemical-Metallurgical Branch of the Research Depart- ment of the Metallgesellschaft, Inc. (ZFC of MG) gives the available details of this procedure, which may be regarded as a further development of the process in commercial use since 1911 at a ceramic plant in Hoeganaes, Sweden. The Bureau of Mines' wartime development of the Hoeganaes process also cul- minated in the adaptation of ceramic tunnel kilns for carrying out the solid- carbon reduction of iron ores, and comparison with the German technique should further advance the art. This information circular is issued as a supplement to Bureau of Mines reports of investigations Nos. 3819,2 3822, 3841,2 and 4271, on brick- yard sponge iron and is based on four German reports entitled "Making Iron. Powder in the Tunnel Kiln," translated from FIAT microfilm reel H-46, frames 9190-9209, 9280-9299, 9339-9357, and 9377-9384 (PB L 70042), which represent the four original research reports, Nos. 2005, 2008, 2010, and 2012, respec- tively, of the Metallgesellschaft, Inc.

Aug 1, 1948

By H. E. Powell

A laboratory mineral-dressing investigation was conducted by the Federal Bureau of Mines on four limonitic and four sideritic iron ores from the North Basin of the east Texas iron-ore district. The samples, composited from drill cores, were considered representative of the iron-ore reserves of the area. The objectives of this research were twofold: (1) To devise a mineral-dressing method whereby the yield from currently mined east Texas iron ores might be increased and the grade improved, and (2) to extend such treatment to include the lower grade ferruginous materials that are not amenable to beneficiation by simple washing and, therefore, are not being exploited. Of the mineral-dressing methods used in this investigation, magnetic separation of roasted are was shown to be the most effective. Results show that, by this method, a laboratory recovery of 82 percent of the iron is attainable at a grade surpassing that obtained by current plant practice and that both limonite and siderite are amenable to concentration by the process. The existence of large deposits of iron are in eastern Texas has been recognized for over 100 years. These ores were first exploited during the Civil War and were mined intermittently until about 1911. From that time until 1944 when the Defense Plant Corporation financed the erection of three blast furnaces to use these east Texas ores, production was almost at a standstill.4/

Jan 1, 1960

By C. M. Paiencia

The Bureau of Mines studied the potential availability of primary antimony (Sb) from demonstrated resources in 21 mines and deposits in market economy countries (MEC's). Twelve of these properties were evaluated as producers and nine as non- producers. The 21 studied properties contain 499,600 mt Sb as demonstrated resources, of which 304,000 mt is recoverable as antimony metal; another 973,500 mt Sb is contained in inferred resources. Recoverable antimony from demonstrated U.S. deposits is only 10,700 mt, just 3.5 pct of the MEC total. Domestic production of primary antimony from operating mines has averaged only 561 mt/yr over the 10-yr period 1975-84. This represents just over 5 pct of total U.S. consumption of primary antimony, which averaged 11,081 mt/yr during the same period. The United States will thus continue to rely on imported ores andlor concentrates, antimony oxides, and metal to satisfy domestic industrial requirements. At production costs up to $1.15/lb Sb, 110,000 mt of refined antimony is potentially available from 10 of the 21 studied properties. At $2/lb, 294,000 mt Sb is available, and at $3/lb, the total rises to 304,000 mt Sb available from all evaluated producers of refined antimony.

Jan 1, 1986

By Alan R. Buehler

A mineral survey of the 67, 110-acre Raven?s Eye WSA (Wilderness Study Area) in the north-central Snake River Plain of Idaho was conducted by the U.S. Bureau of Mines in 1985, at the request of the Bureau of Land Management. The WSA is in Blaine and Lincoln Counties; the northwest corner is about 1 mile east of Carey, 10. A search of county mining claim records indicated that no claims have been located in the WSA. Basaltic lava is the only rock type exposed within the WSA. A platy variety of lava (slab pahoehoe) occurs that is produced from other lava fields in southern Idaho. The material is marketed as decorative stone, used for wall veneers, and retails for approximately $125/ton. Within the W5A, approximately 18,000 tons of indicated reserves are concentrated in two areas, and a total of 12,000 tons of indicated subeconomic resources were found at six other localities. An additional 10,000 tons of inferred subeconomic resources are unevenly distributed over the remainder of the WSA.

Jan 1, 1986

By M. J. Brevoort

Research work in the Bureau of Mines cryogenic laboratory requires the use of high-sensitivity galvanometers of the d'Arsonval type in a building that is subject to unusually severe vibrations. A modified form of the galvanometer suspension described by Julius' has damped the vibrations so successfully that a short note concerning it is thought to be desirable. The laboratory is on the site of the Amarillo helium plant near a building that houses gas engines of from 180 to 250 hp driving compressors and electric generators. The distances from the galvanometers to the individual engines range from about 80 to 180 feet. The subsoil, consisting of black clay loam, transmits the impulses without much damping. The usual methods of protecting galvanometers from vibration were tried and proved fruitless. A Julius suspension purchased on the market was carefully installed in the hope that it would overcome the difficulty, but the conditions were too severe even for this elaborate arrangement. Several modifications of the original Julius suspension, which were then introduced, resulted in almost complete elimination of all vibrational effects. These modifications were suggested by careful study of the original idea embraced in the Julius construction. They were designed to give further constraint to motion in any direction other than that parallel to a line from the point of support through the center of gravity of the suspension, This was accomplished by making the suspended frame more rigid and by improving the means of adjusting each of the supporting wires to the same degree, thereby transmitting any impulse symmetrically through the three wires. The result was a suspension that is more effective, particularly for severe vibration, than the form described by Julius; also, it is believed to have advantages in stability, simplicity, and ease of adjustment over the few suspensions for this type of service that the author has found described in the literature.

Jan 1, 1931