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By Jerry J. Gray

Transportation charges for mineral commodity movements in western Oregon and western Washington were determined mainly by a stratified random sample canvass of producers. Total 1965 mineral production value for this area was $53.3 million; the cost or charge to move this production from the mine to the consumer or to the point of consumption was determined to be an additional $38.7 million. Thirty seven companies were contacted as a sample out of a total population of 349; the statistically expanded sample production value deviated 3.6 percent from that obtained by the Bureau's annual canvass. The agreement between the sample results and the canvass totals demonstrated the effectiveness of the sampling method for obtaining data with a predesigned level of accuracy. For comparison, the north-central Idaho and western Montana area was studied, A random sample experiment was designed, but because of the dominance of a few major companies, a random sample technique would have required more visits to producers than if only the larger firms were contacted. Eighty-four percent of the 1966 mineral value ($198.6 million) was accounted for by interviewing 27 firms out of a total population of 199. Total transportation costs or charges for the area were $26.7 million. The significant difference observed between the relationship of minerals production value and transport charges between the two areas investigated can be attributed to the difference in the minerals produced. The western Oregon and western Washington region is a nonmetals-producing area as opposed to the predominance of metals production in the Idaho-Montana region.

Jan 1, 1968

By R. D. Leitch, W. P. Yant, A. C. Fieldner, R. R. Sayers, S. J. Pearce

"The detection of leakage is a recognized problem in the safe and economic distribution and use of natural gas. Natural gas is practically odorless and therefore lacks he property of indicating significant leakage by the sense of smell, the means most widely used by gas employees and consumers for detecting leaks of the more odorous types of fuel eases. In view of the recognized value of the odor of gas for indicating leakage at the time of occurrence the Bureau of Mines has studied' the possibility of adding small amounts highly odorous substances to types of fuel gas (such as blue water gas and natural gas) that lack warning properties. These studies revealed that the mercaptans were promising substances to accomplish this purpose, not only for odorizing fuel gases but for other purposes° where it was desired to give warning through the sense of smell.Since completing the studies mentioned, the Bureau of Mines jointly with the American Gas Association has conducted further investigations dealing with the use of warning agents for fuel gases. The results of this work will be published later.The Bureau of Mines had been desirous of observing the practical use of ethyl mercaptan for detecting leakage of natural gas, particularly to determine whether the odor would permeate the ground and give indication of lea's in underground pipes. Opportunity for making these observations was recently given by E. A. Munyan, manager, gas department, Union Gas t Electric Co., who requested the bureau's cooperation in making leakage surveys of the company's distributing systems at Franklin and Middletown, Ohio."

Jun 1, 1930

By Thomas M. Barczak

The U.s. Bureau of Mines is conducting research to optimize the utilization and design of mine roof support systems. This report describes methods to evaluate resultant loading on longwall shields, defined as external resultant vertical and horizontal force acting on the canopy and base. Four models are considered: two rigid-body models, an elastic model, and a numerical model. The rigid-body models equate measured internal shield forces to unknown external resultant shield forces (loads) through rigid-body analysis of static equilibrium requirements. The elastic model develops a solution to shield mechanics by evaluation of the load-displacement relationship and stiffness characteristics of the support structure. The numerical model is a two-dimensional finite-element representation of a shield structure. Model determination of resultant shield loading is compared to controlled loading of a shield in the Bureau's mine roof simulator. Parameters investigated are shield height, canopy contact configuration, canopy and base horizontal constrainment, and boundary conditions imposed by vertical and horizontal shield displacements. It is concluded that rigid-body models are most applicable to in situ measurement of shield loading. Applications requirements and potential error sources are discussed.

Jan 1, 1990

By Juel H. Stears

Research was done to determine if a hydraulically operated penetrometer developed by the Bureau of Mines could be used to estimate the roof-bolt anchorage capacity of mine roof rock. Tests were conducted both in the laboratory using cement cylinders and underground in shale rock. Hardness readings were measured by the penetrometer around the periphery of the bolt holes at the anchorage horizon. Roof bolts Nere then installed and subjected to an anchorage test. The results showed that the penetrometer readings could be used to determine the optimum stratum for roof-bolt anchorage but could not be used to make an accurate estimate of the anchorage capacity.

Jan 1, 1965

By R. Van A. Mills

Crude oils are capable of dissolving quantities of gas under pressure. This fact has been known for some time, but questions have arisen as to the effects of gas in solution upon the characteristics of the oil. Previous investigations4 show that gas in solution in an oil affects the viscosity and surface tension of the oil, but the effect's on the volume and A. P. I. gravity of the oil have not been known. The results given in this report show that there is a decided change both in volume and in the A. P. I. gravity of the oil due to the solution of the gas in the oil under pressure. As gas is dissolved, the volume of the oil and the A. P. I. gravity increase. The converse of this phenomenon is also true: if the gas is released from a saturated oil, there is a shrinkage in volume and a decrease in A.P.I. gravity due to the release of gas from solution. However, various oils show marked tendencies to retain a portion of the dissolved gas upon releasing the pressure to that of the atmosphere. This retained gas has an appreciable effect on the volume and A. P. I. gravity of the oil because the oil does not resume its initial volume or gravity while it retains dissolved gas. In a sense the oil has been "Freshened" and will not return to its original or weathered volume until it loses some of the lighter fractions. Wiggins5 has shown that a fresh oil decreases both in volume and in gravity because of the weathering of the lighter fractions while the oil is standing in storage tanks.

Jan 1, 1928

An active list of permissible explosives was published in December 1936 as part of Bureau of Mines Report of Investigations 3324, under the title "Active List of Permissible Explosives and Blasting Devices Approved Prior to July 31, 1936." This list included 170 brand names. Changes in the list that have been authorized to June 30, 1937 placed 35 additional brands of permissible explosives on the active permissible list as a result of tests, changes in brand names, or transfer from the inactive list. Ten permissible explosives were transferred from the active to the inactive list. The present list contains 196 brand names, one explosive having been placed on the list subsequent to June 30, 1937. The brand names of the permissible explosives placed on the active list are as follows:

Jan 1, 1937

By Robert Stefanko

Transients are results of sudden changes which take place in power systems and can be created by the opening and closing of switches and circuit breakers or the occurrence of a fault anywhere in the complex. Transients are of short duration, and the time during which they occur is an extremely small percentage of the total operating time. However, it is during these short periods that the greatest electrical stresses occur, mainly due to excessive currents or voltages. In extreme cases, system parts are damaged, and equipment failure follows. Safety can be further compromised because anomalous voltages can exist at machine frames. For several years, the electric utilities have been well aware of the serious nature of transients on their systems, but problems firmly believed to directly result from these phenomena are just now becoming apparent to the coal mining industry. The situation became discernible after the underground introduction of high voltage distribution systems (along with vacuum circuit breakers) and sensitive solid state electronic apparatus. In order to protect against such transients, knowledge about their characteristics and origin must be obtained.

Jan 1, 1974

By A. E. J. Gallagher

This report summarizes the results of flotation studies conducted by the Federal Bureau of Mines on samples of extremely fine-grained lead-zinc sulfide ores. Samples from five ore deposits in the Pine Creek area, Coeur d'Alene district, Idaho, and one deposit in the Metaline district, Washington, were studied at the Albany Metallurgy Research Center to determine the recovery of sulfide lead and zinc by flotation. During the investigation it was found that flotation could be effectively applied to the selective recovery of exceedingly fine-grained lead and zinc sulfide minerals. Separation of galena and sphalerite was obtained on pulps ground through 1,600-mesh, in which most of the particles were smaller than 5 microns. Selectivity and recovery of minerals in this fine size range were enhanced by use of a chemical dye, diphenylthiocarbazone, as a galena promoter. Although unsuccessful on one ore, application of the dye in treatment of two other very fine-grained ores yielded lead concentrates containing over 62 percent Pb at recoveries in excess of 85 percent. More than 55 percent of the lead in these concentrates occurred as particles smaller than 2 microns.

Jan 1, 1961

By Walter R. Storms

The Iron Mountain tungsten deposits first were visited by a field party of the Federal Geological Survey in May 1942 while beryllium deposits in that district' were being examined . Later they were examined by F. A. Rutledge , an engineer of the Bureau of Mines , and an exploration project was recommended , work upon which began in March 1943 and was terminated in April 1943 after intensive trenching and sampling had been completed .

Mar 1, 1947

By Leslie D. Marrus

This project and final report represent an effort to collect, analyze, and verify reliability and performance data on currently available medium -to-high seam models of continuous miners being used in underground coal mining. The analysis determined availability, mean time and tons between failures, amounts of down time associated with various failures, labor and part costs required to correct failures, and various indices of maintainability. Machine performance and reliability are discussed relative to cumulative tons (machine age) produced and production rates (machine loading). It was determined that performance can be significantly improved given preventive maintenance programs that will increase machine availability.

Jan 1, 1976

This study was done to evaluate the economic and technical considerations of using pozzolanic materials in order to guide cement manufacturers, pozzolan producers, contractors, Government organizations, and others interested in concrete construction work. Five hundred and thirty-eight samples of pozzolanic raw materials were taken from 27 central and western States. These samples were evaluated by petrographic procedures, and about 200 of the most promising ones were given a complete series of physical tests (American Society for Testing and Materials) to evaluate further their suitability as a pozzolan. This investigation showed that deposits of natural pozzolan materials were widely dispersed in the central and western parts of the United States but that exploiting these deposits would depend on whether they could compete economically with an increasingly abundant industrial waste product--fly ash.

Jan 1, 1969

By L. L. Oden

The Bureau of Mines has studied a number of processes to remove Cu from molten steel scrap with the objective of determining if any of the laboratory methods studied warranted in depth research investigations. Experimental approaches included oxidizing Cu from steel containing other metals that form stable mixed oxides with Cu (AI, Cr, Fe, Mn, Mo, and V), injecting the same metals as oxides to simplify the mechanism of complex oxide formation, partitioning Cu into alkali or alkaline earth silicate slags or oxide-moderated sulfides, and coremoving Cu and S by injecting active compounds of Ca and Mg. The most promising tests, producing nearly 0.3 pct Cu in the slag, used Ar injection of K20-moderated Na2S-FeS below the surface of molten steel containing about 0.6 pct Cu and protected by a CaO-SiOz slag; however, in depth research investigations currently are not felt to be warranted.

Jan 1, 1987

By A. E. Raddatz

The Federal Bureau of Mines, as part of its goal to minimize undesirable environmental impacts associated with mineral processing, has investigated a soda-smelting technique for processing ilmenite into pig iron and a titanium slag that is suitable for a feed to a sulfate-process titania pigment plant. By this procedure, the generation of ferrous sulfate waste and its associated disposal problem is obviated. Molten titania slag was quenched, water leached, and filtered to yield a sodium titanate intermediate product containing about 70 wt-pct Ti02, 1 wt-pct Fe, and 20 wt-pct Na20. This intermediate product, high-soda titanate (HST), was mixed with H2S04, calcined, quenched, and water leached to produce a low-soda titanate (LST) product that contained only 2 wt-pct Na20. Both the HST and LST were evaluated as feed materials for preparing titania by the sulfate process. About 95 pct of the Ti02 was extracted from HST and LST by digestion in concentrated or 50-wt-pct-H2S204 solutions. About 95 pct of the solubilized Ti02 was subsequently recovered from the titanyl sulfate solutions by hydrolysis. Barren solutions from hydrolysis, containing about 26-wt-pct H2S04, were upgraded by vacuum-thermal evaporation or electrodialysis. The regenerated acid solutions were used to digest additional HST and LST.

Jan 1, 1979

By Allen McComas, Frank Chase, Phyllip Worley

Longwall mining has gained the reputation as being the safest extraction method in underground coal mines. However, one of the most difficult tasks associated with longwall mining is moving the face once a panel is completed. Based on Mine Safety and Health Administration (MSHA) fatality reports since 1996, longwall face recovery operations have claimed the lives of 5 U.S. miners and have resulted in numerous injuries. Recovery operations can be hazardous because they involve moving large pieces of equipment in very confined spaces. They are also conducted in highly stressed ground conditions due to front abutment loads generated by panel extraction. Shield removal is the most hazardous operation during face recovery because miners are constantly exposed to the unpredictable gob edge. To protect the miners, one or more walking shields, cribbing and/or other supplemental roof and standing supports are typically employed as breaker line supports as each shield is removed. At the Harris No. 1 Mine in southern WV, mobile roof supports (MRS’s) have been used in lieu of traditional walking shields on 17 face moves since 1997. MRS’s are shield-like support units mounted on crawler tracks and are commonly used during room-and-pillar retreat mining operations. For longwall recovery, the two biggest advantages that MRS’s have over traditional walking shields are that they are remotely controlled and are highly maneuverable. MRS’s have contributed to safer shield recovery and shorter move times at the Harris No. 1 Mine. This paper will address both the safety and the operational issues associated with MRS usage during shield recovery. It will also discuss new developments, including the use of the inherently safer battery powered MRS’s, which have been recently certified by the Mine Safety and Health Administration.

By Richard F. Hewlett

Use of digital computers makes possible a more efficient and complete analysis of data from a mineral deposit . This computer program was written and used during an investigation into the efficiency of methods of computing grade and tonnage of ore , wherein it was necessary to make repeated computations involving different combinations of data . This investigation was part of a continuing program of sampling methods research at the Bureau's Denver Mining Research Center.2-4 This program is designed to compute tonnage and average grade for 40 cutoff grades using either the statistical or polygonal methods . tational rate is from 200 ( input bound ) to 1,400 assays per minute , depending on the use of either individual ( one assay per card ) assay- interval length or

Jan 1, 1963

By Omotayo Kalejaiye

The Siwek 20-L chamber is widely used throughout the world to evaluate the explosibility of dusts. This research evaluated the quality of dust dispersion in the Siwek 20-L chamber using Pittsburgh coal, Gilsonite, and purple K dusts. A Pittsburgh Research Laboratory (PRL) optical dust probe was used to measure optical transmittance through the dust cloud at various locations within the chamber. A total of 540 tests were performed, with triplicate tests at five nominal dust concentrations and six locations. The two standard dispersion nozzles (rebound and perforated annular nozzle) were compared. The transmissions corresponding to the normal ignition delay period were used to: (a) determine variations in spatial uniformity of dispersion obtained with both nozzles; (b) make comparisons between the experimental transmission data and those calculated from theory for the three dusts; and (c) make comparisons with transmission data measured in the PRL 20-L and Fike 1-m3 dust explosion chambers. The uniformity of dispersion for the three dusts was similar with both nozzles, despite the differences in nozzle geometry and mode of operation. Transmission data of the three dusts were all significantly lower than those calculated from theory. This was discovered to be, in part, due to significant reduction in particle size that occurred during dispersion. By measuring particle sizes before and after dispersion, values of 60%, 50%, and 20% reduction in particle size (based on the surface-weighted mean diameter) were obtained for Pittsburgh coal, Gilsonite, and purple K, respectively. Transmission data from the PRL 20-L, Fike 1-m3 and the Siwek 20-L chambers indicated comparable results in terms of uniformity of dispersion. However, transmission data from the Siwek 20-L chamber were significantly lower than those of the PRL and Fike chambers. Again, this was attributed, in part, to the significant reduction in particle size that occurred during dispersion in the Siwek chamber. The design of the outlet (dispersion) valve of the Siwek 20-L apparatus charge vessel was largely responsible for the particle break-up. The contribution to particle break-up by the dispersion nozzles and the high level of turbulence in the chamber were found to be minimal. This is a significant finding in that the dust particle size tested for explosibility in the Siwek chamber is considerably smaller than the original dust sample.

Jan 1, 2010

By P. J. Colbassani

Samples of mine atmospheres collected by Federal coal-mine inspectors during their inspections and investigations of coal mines, in accordance with provisions of the Federal Coal Mine Safety Act (66 Stat. 692; 30 U. S. C., sees. 451-483) are analyzed routinely by chemical methods at Bureau of Mines laboratories. When samples collected in open workings of nongassy coal mines at points not less than 12 inches from the roof, face, or rib contain 0.25 percent or more methane, the act requires the operator, during operation of such mine, to comply with the provisions of sec. 209, Title II, of the act, which pertain to gassy mines. The methane con-tents of such samples are determined by a physical method based on infrared absorption spectrometry to provide an independent check on analytical results obtained by chemical methods. This information circular describes the equipment and procedures used by the Bureau for determining low concentrations of methane in coal mine atmospheres by infrared absorption spectrometry. ACKNOWLEDGMENTS The authors are indebted to Dr. R. A. Friedel, Chief of Spectrometric Section, Branch of Coal-to-Oil Research, Bureau of Mines, for suggesting the analytical method and for furnishing valuable advice and assistance, and to J. A. Queiser of his staff for making exploratory measurements by this method; to Dr. M. G. Zabetakis of the Division of Explosives Technology for his assistance during the conduct of preliminary experimentation; and to L. B. Berger, Chief, Branch of Health Research, under whose guidance the equipment was procured and the work conducted.

Jan 1, 1958

By Philip C. Good

Unweathered low-grade calcareous phosphate rock of about 20 percent P205 grade was beneficiated by a procedure in which contained carbonates were decomposed by calcination at about 1,000° C. On quenching the hot calcined rock in water, major impurities passed into a slime phase which was mechanically separated from a coarser concentrate fraction. Phosphate rock of two major types was beneficiated in batch-scale studies yielding concentrates containing 31.3 to 38.5 percent P205 at recoveries ranging from 54.8 to 86.0 percent. The samples were from two major deposits in India. Processing information gained was utilized in extending the work to a continuous-flow system, processing phosphate rock at rates up to 157 kilograms per hour. Superphosphate exceeding 16 percent water-soluble P205 was prepared from concentrate derived from continuous-flow processing.

Jan 1, 1976

By Catharine T. Fogg

The Bureau of Mines investigated the availability of flake and high-crystalline natural graphite from 4 domestic and 25 foreign mines and deposits in 11 market economy countries (MEC's). Demonstrated resources were estimated to be 95 million metric tons (Mmt) containing 5.61 Mmt of recoverable flake and high-crystalline graphite products. Fifty-five percent (3.17 Mmt) of the total recovered product is estimated to comprise plus 100-mesh (150-µm) flake pro-ducts and "lump" and "chip" high-crystalline products, designated as "graphite A" in this study; 45 pct (2.44 Mmt) of the total is minus 100-mesh (150-µm) flake products and "dust" high-crystalline products, designated as "graphite B." Total production costs, including all costs needed over the life of each operation, were determined at a 0-and 15-pct discounted-cash-flow rate of return (DCFROR) for both graphite A and graphite B products. For a 15-pct DCFROR, 1.74 Mmt (54.9 pct) of the graphite A products is available at $600/mt or less and 2.13 Mmt (67.2 pct) is available for $800/mt or less. For the same DCFROR, 1.08 Mmt (44.3 pct) of the graphite B is available at $200/mt or less, and 1.71 Mmt (70 pct) is available at $325/mt or less. No domestic resources were determined to be economic at present prices. A sensitivity analysis of the relative economics of the Alabama graphite deposits under various operational parameters is presented in an appendix. All evaluations are in January 1984 dollars.

Jan 1, 1987

By Jun Yi

In this paper, single-component gas sorption and transient diffusion processes are described within coal matrix exhibiting bimodal pore structure. The coal matrix is treated as a poroelastic medium manifesting swelling and shrinkage effects due to the sorption of gas under effective overburden stress. Gas transport is considered Fickian with molecular (bulk) and surface diffusion processes simultaneously taking place in the macro-and micropores of coal, respectively. The numerical formulation is intended to be explicit in nature to investigate the influences of sorption phenomena on the macropore volumes and on the overall gas transport for the cases of gas uptake by and release from coal. Results of the study show the presence of hysteresis during a sorption?desorption cycle of the gas. It is also found that the overall gas transport takes place at a rate significantly less than that in the macropores only. Thus the existence of a retardation effect in the overall gas transport is concluded. This retardation effect is primarily due to the micropore resistances, in particular gas adsorption, and is independent of the changes in the macropore volumes. It is shown that macroporosity of the coal matrix may change during gas transport due to combined effects of pressure and sorption-induced swelling or shrinkage of the coal. It is estimated that the macroporosity variation is non-uniform in space and time, as it is expected in reality, and typically taking values less than ±10 percent of the initial porosity.

Jan 1, 2009