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By K. C. Dean

A flotation method was developed by the Bureau of Mines for concentrating pollucite, a cesium-aluminum-silicate mineral that may contain from 20 to 40 percent cesium oxide. Separation of the pollucite from three typical ores was achieved by froth flotation of the associated micas, feldspars, and other gangue minerals, using sulfuric and hydrofluoric acids and a cationic-type collector. A low-tenor, 8 percent cesium ore from Maine was upgraded to 20 percent cesium with recovery of 87 percent of the cesium. Relatively high- grade ores from Canada and Southern Rhodesia were beneficiated at lower ratios of concentration to 28 and 29 percent cesium content respectively with recovery of over 92 percent of the cesium. In addition to concentrating the cesium content of ores, the method also effectively separates cesium from sodium, potassium, and lithium, and in certain ores from rubidium. This is accomplished by selective froth flotation of the alkali metal-bearing gangue minerals such as lepidolite, other micas, and feldspars. Since the alkali metals, especially potassium and rubidium, are difficult to separate chemically or thermally from cesium to prepare high- purity cesium products, separation by physical mans is important.

Jan 1, 1962

To address the safety of programmable electronics-based mining systems before this technology proliferates in the mining industry.

Jan 1, 1999

By W. M. Dressel

The objective of the research reported in this publication of the Federal Bureau of Mines was to devise a mineral dressing procedure that would concentrate zinc silicate minerals from certain deposits in southwestern Missouri. The best flotation results were obtained by batch laboratory flotation using sulfidizing agents and ethoxylated cocoamine. The flotation concentrate contained 70 percent of the zinc at a grade of 47.8 percent. Gravity concentration tests showed that 55 percent of the zinc could be recovered at a grade of 48.3 percent.

Jan 1, 1961

By B. K. Shibler

A highly flexible laboratory-scale fluidized-bed reactor was designed, constructed, and successfully operated continuously at temperatures up to 1,300° C during an investigation of thermal methods for decomposing gypsum. This report discusses briefly the many problems encountered in developing the 10-inch-diameter reactor and describes its design and construction in sufficient detail to enable other research organizations to build a comparable unit. The reactor consists of a 10-inch-inside-diameter vertical tube which can be varied from 6 to 10 feet high; it is formed from 2-and 3-foot sections of silicon carbide pipe. The tube is surrounded by a 3-inch heating space formed by an outer 4.5-inch-thick circular wall of insulating firebrick. A cone-shaped fluidizing chamber is bolted to the bottom of the reactor. Fluidizing gas enters through the bottom of the cone, and ore is introduced by means of a screw feeder connected to an inlet located just above the gas port. A silicon carbide overflow tube of 1.25-inch inside diameter extends upward into the reactor. The depth of the bed is controlled by substituting different lengths of overflow tube. Twin dust-recovery systems, each composed of a cyclone and Fiberglas filter, are attached to two gas outlets at the top of the reactor tube. The reactor is designed for research on both exothermic and highly endothermic reactions. It can be fired externally by means of four natural gas burners that jet tangentially into the annular space at the base of the reactor. Alternatively, it can be fired internally, using a mixture of air or oxygen and natural gas as the fluidizing medium. A separate instrument panel contains flowmeters, manometers, an automatic program controller, and a multiple-point recorder for printing a record of the temperatures measured by thermocouples located at critical points in the reactor.

Jan 1, 1963

By R. J. Morrell

The Bureau of Mines conducted a series of laboratory experiments to test a cutting technique for hard rock using large-scale drag cutters. Cutting experiments were performed on rocks ranging in compressive strength from 10,000 to 27,000 Ib/in2, using large drag cutters from 3 to 6 in. in width. The tests were conducted on a special test apparatus, called a ripper tester, which made a curvilinear cut across the rock sample while measuring the cutting force acting on the drag cutter. The cutting method that evolved from these experiments is called ripper cutting, and its energy efficiency appears superior to all other large-scale mechanical fragmentation techniques. In addition, the method cre-ated very little dust, and the wear on the bits was negligible. A fragmentation system based on ripper cutting was then devised, and a large-scale test device was fabricated to allow full-scale laboratory testing of the system. The results of these tests will be published in future Bureau reports.

Jan 1, 1986

By P. C. Van Natter

Numerous mine fires have resulted in high death tolls and considerable finan¬cial loss during the history of coal mining. In most instances the death toll and financial loss were greater because of inadequate fire-fighting facilities. The information in this report is presented in the hope it may serves as a guide in the selection, placement, and care of fire-protection systems in similar coal mines. The adequacy of fire protection varies according to size of operation, employment, and production. When fires occur on the surface or underground, measures must be applied quickly to prevent incipient fires from spreading. The record of coal-mine fires shows that, in many instances, facilities for combating fires were very meager or were absent. It would be virtually impossible to establish and maintain all the necessary facili¬ties that may be needed to extinguish widespread mine fires, but it is believed that the coal industry can ill afford less than the minimum required by other industries where the time element and avenues of escape are much more favorable.

Jan 1, 1958

By W. M. Traver

As a direct result of the second World War, consumption of nickel in the United States has increased to such an extent that it has been considered timely to investigate undeveloped deposits of the nickel minerals. Funds were made available to the Bureau of lines in 1941 to investigate the extent, occurrence, and quality of nickel ores in the Mirror Harbor area. The Federal Geological Survey mapped' and studied the area during the summer of 1941 and Robert S. Sanford, an engineer of the Bureau of lines, made a preliminary examination in June 1942. A contract for drilling the deposits under the direction of the author was let in July 1942.

Jan 1, 1948

By Frank E. Cash, John A. Johnson

"INTRODUCTION During the 6-year period, 1940-45, 481,485,000 gross tons of iron ore was shipped from the Minnesota, Michigan, and Wisconsin mines of the Lake Superior district. Approximately 367,000,000 tons, or 76 percent, of this ore was shipped from open-cut mines. The production of this large tonnage of iron ore from the open-cut mines of the Lake Superior district during the recent war was an outstanding achievement. It is questionable whether this record-breaking tonnage of iron ore, vitally needed for the successful prosecution of the war, could have been produced without the modern equipment and mining methods used in the district, The transportation of iron ore from the open-cut mines of the district is the most important phase of the mining cycle. Although some of the mines still use rail haulage advantageously, this method of haulage has been replaced at most nines with motor-truck haulage or a combination of motor-truck and belt-conveyor haulage.SCOPEThe transportation of iron ore in this report covers (1) power shovels, (2) rail haulage, (3) trucks, (4) belt conveyors, (5) shipping pockets, (6) accident statistics, and (7) safety rules pertaining to open-cut transporta¬tion. The purpose of the report is to discuss briefly and disseminate to the mining industry the modern methods, equipment, and safety practices used in transporting iron ore at the open-cut mines of the district.The 25 open-cut mines covered herein, located in the Marquette, Cuyuna, and Mesabi iron ranges of Michigan and Minnesota, shipped approximately 44,000,000 tons of iron in 1945, which amounted to 72 percent of the open-cut iron ore shipped from the Lake Superior district."

May 1, 1948

By George T. Motock

The author prepared the following report as the result of a trip to Germany in the summer of 1945 for the Technical Industrial Intelligence Commitee Subcommittee on Metals and Minerals. The purpose of this committee, which functions under the Joint Intelligence Committee of the Joint Chiefs of Staff of the United States Armed Forces and of which the Bureau of Mines

Jan 1, 1946

By H. Herbert Hughes

Iceland spar is a variety of calcite ( calcium carbonate ) characterized by its purity , transparency , and perfection of crystalline structure . It takes its name from the country in which it was discovered . The actual demand for it is small , but the supplies of high - grade optical spar are so meager that the search for it has become international in its scope . Iceland spar is a scientific necessity , for without it research precision and technology would be hampered considerably . The earliest students of mineralogy were familiar with calcite , but the transparent variety was not discovered until early in the seventeenth century , when crystals of it were found in the bed of a stream in Iceland . It received little attention until 1669 , when Erasmus Bartholinus first recognized its powers of double refraction . The results of his investigation were published in a book , " Experimenta Crystalli Islandici , " which appeared in 1670. The law governing the action of the rerracted rays was discovered by Christian Huygens eight years later . The polarization of light rays in passing through Iceland spar was discovered in 1809 by Etienne Louis Malus , a French physicist , who published a paper describing the phenomenon . His work was closely followed by that of William Nicol , who in 1828 designed the Nicol prism which is still used as the source of polarized light in most optical instruments .

Jul 1, 1931

By C. P. Mangelsdorf

When the finely bedded shale frequently encountered over coal seams experiences a separation, the material below the separation must behave like a beam or plate in that it must resist both bending and shear. Be-cause of the weakness in interlaminar shear inherent in such strata, shear deflections that are usually ignored in isotropic beam theory may account for a significant part of the total roof sag. Similarly, when a roof truss is installed in such a roof the upward displacement reducing the sag will have components due to shear as well as bending. Questions asked by mine operators about the installation of roof trusses frequently deal with optimum position, slope, and initial tension of the inclined chords. This Bureau of Mines report examines the effects of those chord parameters on the strain energy of both shear and bending and offers optimum values that will minimize the total strain energy of the immediate roof. Design charts are provided, several design examples are included, and the results are compared with current practice. The effects of in situ stresses are investigated and are shown to be equivalent to an additional load on the beam.

Jan 1, 1988

By John C. Edwards

Several experimental programs were conducted at the Pittsburgh Research Center to investigate the level of mine fire detection and alarm capability possible using state-of-the-art technology. These programs involved comparison of the response and alarm time of optical and ionization type smoke sensors to smoldering and flaming coal combustion in a smoke chamber. Coal combustion experiments conducted in the smoke chamber demonstrated that a CO concentration of 5 ppm above ambient corresponded to an optical density of 0.022m1. For the four smoke sensors for which a continuous analog signal was available, a smoke sensor alarm was defined as the average background signal plus ten times the peak-to-peak noise. This alarm criterion resulted in the association of the alarm for three of the four sensors with a smoke optical density of 0.022m-1. and 0.033m-1 for the fourth smoke sensor. The smoke sensors used in the smoke chamber studies were incorporated into large scale diesel fuel fire experiments conducted under normal ventilation conditions in the Safety Research Coal Mine (SRCM) at the Pittsburgh Research Center. These experiments showed that a diffusion mode smoke sensor alarmed earlier than a diffusion mode CO sensor; and, based upon the measurement of the optical transmission at the location of a pump mode ionization type smoke sensor that a pump mode ionization smoke sensor alarmed at an average smoke optical density of 0.021m" for the twelve experiments conducted. A series of 30 and 330 kW diesel fuel fire intensity experiments were conducted under zero airflow conditions in the SRCM. It was determined that :(I) thermal sensors are inadequate at 30 m from a 300 kW fire;(2) a diffusion mode ionization smoke sensor can be more effective for mine fire detection than a diffusion mode CO sensor;(3) recommendations can be made for sensor spacing in a mine entry based upon the measured CO buoyancy induced spread rates along the mine roof and the time for a developing coal fire to ignite a conveyor belt.

By J. M. Stuve

Standard heats of formation (AH°p) of YbCl3 (c) and TmCl3 (c) were measured by solution calorimetry. Heat of solution data are given for ytterbium and thulium metals and corresponding anhydrous trichlorides in 4.360 molal hydrochloric acid. The derived standard heats of formation of YbCl3 (c) and TmCl3 (c) were -229,370 ±720 and -235,820 ±400 cal/mole, respectively, at 298.15° K. The resulting heats of formation for YbC13 and TmCl3 are about 1 kcal and 6.3 kcal more negative than previously published values.

Jan 1, 1967

By Jack L. Henry

A laboratory and a pilot-plant-scale investigation has been conducted by the Bureau of Mines to examine possible sources of nitride defects in the production of magnesium-reduced titanium sponge. The production of alpha-stabilized nitride inclusions in hot-rolled titanium plate from air contamination of sponge during its manufacture has been experimentally demonstrated. Magnesium-reduced sponge prepared from air-contaminated magnesium or when contaminated by an air leak during reduction, vacuum distillation, or inert gas sweep, shows very large variations in nitrogen content. Refractory nitrides, delta TiN and epsilon Ti2N have been identified in this sponge. The highest incidence of inclusions resulted from sponge that was reduced by air-contaminated magnesium and from sponge subjected to air contamination during the vacuum distillation cycle and during helium sweep. Air contamination of sponge during the reduction cycle was not nearly as effective in producing inclusions. Tests showed that color and texture may not be reliable criteria for locating defects during sponge inspection. Maintenance of good vacuum-tight integrity, filtration of molten magnesium prior to charging into the reduction retort, and mechanical attrition of sponge to pulverize and disperse nitrides are suggested as practices to lower inclusion incidence in commercial titanium ingots.

Jan 1, 1974

By R. E. Perry

To develop new or improved flotation methods for beneficiating low-grade red iron ores, the Bureau made many bench scale and continuous anionic flotation tests on ferruginous sandstones and calcareous iron ores from the north-eastern part of the Birmingham, Ala., iron district. The ores contained about 21 to 36 percent iron, a to 11 percent lime, and 22 to 64 percent silica. Production of iron concentrates containing 48 to 52 percent iron was technically feasible in batch tests, and the iron recoveries ranged from 85 to 92 percent. In continuous tests 49 to 51 percent iron products were obtained with 80 to 90 percent recovery.

Jan 1, 1962

By Thomas M. Barczak

This Bureau of Mines report describes research on developing technology to utilize shields as roof load monitors. Three-dimensional equations of static quilibrium are presented for a generic two-legged long-wall shield. The equations are presented in the most general form, assuming a force and moment vector at each reaction by rigid-body analysis of the shield mechanics. The resulting system of equations was found to be indeterminate to a very high degree. A three-dimensional solution to measurement of the resultant reaction on the canopy by the strata activity and shield response required the elimination of several forces or moments that were thought to be nonparticipating or to not significantly affect overall shield mechanics. Required measurements for solution of the equilibrium equations were leg, canopy capsule, and lemniscate link forces. Two-dimensional analysis, which considered forces acting only in the roof-to-floor and face-to-waste plane, was also provided by reduction of the three-dimensional equations~

Jan 1, 1987

By F. A. Rutledge, H. Marstraander, J. H. Hulbert, G. A. Apell

"INTRODUCTION The inability of Alaska coal mines to supply the quantity of coal required by public and private consumers and by the armed forces in Alaska caused the Coal Procurement Section of the Alaska Department, U. S. Army, to be established. It proposed to investigate the coal deposits and to expedite production of coal. The Bureau of Mines has closely cooperated in this program and was in direct charge of exploration. As to develop and equip an underground coal mine would have taken time and the need for coal was acute, a deposit that could be prepared for mining quickly was desirable. Several such deposits of stripping coal were known to occur in the Nenana field and were examined by the Bureau. One of these, the Diamond strip mine 4 miles west of Healy, was brought into production late in the fall of 1943. This mine was operated for the Army Coal Procurement Section by the C. F. Lytle Co. and the Green Construction Co.The Roth property, or Leasing Block No. 28, in the Healy Creek Valley offered the largest available tonnage of both stripping coal and total reserves. A program of exploration by the Bureau of Mines was inaugurated in 1943 and completed in 1944. Field parties of the Federal Geological Survey mapped the area had correlated the coal beds during the 1944 and 1945 summer seasons."

Nov 1, 1946

The Bureau of Mines conducted a field study to assess the performance of various chain pillar configurations in terms of gate road entry sta-bility. Vibrating wire stressmeters (VWS's) were installed in four consecutive gate road chain pillars. Field data collected during panel retreat were analyzed to gain a better understanding of the mechanics of vertical load redistribution in gate road chain pillars as it relates to ground control problems. Several different pillar configurations were investigated including abutment-yield and yield-abutment-yield designs. VWS data indicate that average pillar loads were lower and appeared abutment-yield pillar arrangement was utilized. port the occurrence of severe roof and pillar to stabilize when an Data analyses also supdeterioration that was visually observed in the tailgate entries during panel extraction.

Jan 1, 1988

By Murray Jacobson

The Federal Coal Mine Health and Safety Act of 1969 established mandatory dust sampling of coal mines according to procedures prescribed in the Mandatory Health Standards, title 30, Code of Federal Regulations, part 70, published in the Federal Register on April 3, 1970. A laboratory was established in the Pittsburgh Field Health Group of the Bureau of Mines to process the coal mine dust samples collected by the mine operators. This paper describes the laboratory and presents the equipment and procedures used in processing these samples.

Jan 1, 1971

Major activities of the Bureau of Mines Explosives Research Center during fiscal year 1965 (July 1, 1964, to June 30, 1965) are reviewed briefly. Part 1 summarizes significant accomplishments of the projects that were active during the report period. Part 2 presents short abstracts of the publications that appeared in the Bureau series and in other media during fiscal year 1965. Publications issued after June 30, 1965 are noted where pertinent in footnotes but are not abstracted. ACKNOWLEDGMENTS The Bureau of Mines gratefully acknowledges the support given through cooperative agreements by the following organizations to investigations con¬ducted by the Explosives Research Center during fiscal year 1965: Dow Chemical Company Manufacturing Chemists' Association Monsanto Chemical Company The Sulphur Institute

Jan 1, 1966