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By Will H. Coghill

Recent work on beneficiation of the .Alabama red iron ores and ferruginous sandstones has brought out interesting new facts on particle-size reduction that axe a valuable supplement to what is already known.4/ The work was done by the Southern Experiment Station of the Bureau of Mines in cooperation with-the University of Alabama, University, Ala., on two samples from the Birmingham district. One was an oolitic red iron ore containing about 35 percent iron; the other was a ferruginous sandstone containing about 25 percent iron, particularly attractive because of its low phosphorus content. In both samples rounded quartz (sand) grains were embedded in an oolitic, "onion skin" matrix of hematite. The hematite carries varying amounts of clay, which limits the grade of concentrate that can be made. The clayey hematite is soft, so that the rock crumbles readily under pressure. The sand grains shell out like corn,, and without much exaggeration the mill used for differential grinding might be called a "sheller,"

Jan 1, 1940

By Will H. Coghill

Recent work on beneficiation of the .Alabama red iron ores and ferruginous sandstones has brought out interesting new facts on particle-size reduction that axe a valuable supplement to what is already known.4/ The work was done by the Southern Experiment Station of the Bureau of Mines in cooperation with the University of Alabama, University, Ala., on two samples from the Birmingham district. One was an oolitic red iron ore containing about 35 percent iron; the other was a ferruginous sandstone containing about 25 percent iron, particularly attractive because of its low phosphorus content. In both samples rounded quartz (sand) grains were embedded in an oolitie, "onion skin" matrix of hematite. The hematite carries varying amounts of clay,-which limits the grade of concentrate that can be made. The clayey hematite is soft, so that the rock crumbles readily under pressure. The sand grains shell out like corn,, and without much exaggeration the mill used for differential grinding might be called a "sheller,"

Jan 1, 1940

By E. G. King

Sodium-aluminum and calcium-aluminum silicates are important rock-forming minerals. While many of them are of only theoretical interest, several are of practical importance--as ceramic raw materials and as potential future sources of aluminum. Heretofore, thermodynamic data for these minerals were incomplete; and in many instances missing data were difficult to estimate reliably. This has seriously hampered thermodynamic calculations pertaining both to the natural formations of these minerals and to their decomposition in sintering and fluxing reactions. This paper reports the results of the Federal Bureau of Mines measurements of low-temperature heat capacities of four crystalline silicate minerals--dehydrated analcite (NaAlSi2O6), hexagonal anorthite (CaA12 Si208), lawsonite (Ca2Al2Si2080?2H20), and leonhardite (Ca2Al4Si8C24?7H2O). It augments previous similar measurements of related minerals, which were summarized recently.4 The measured heat-capacity data were used to derive entropy values for the four minerals at 298.15° K. Some relations between these entropy values and those of other similar minerals were discussed. These relations illustrate the difficulty of estimating entropy values of tertiary (or higher) silicates.

Jan 1, 1961

By Ronald D. Hill, Elmore C. Grim

Coal-haul and mine access roads are defined as any road constructed, improved or used by the operator (except public roads) that ends at the pit or bench. These roads constitute approximately 10% of the total area directly disturbed by the surface mining operation(l). In some cases, the land disturbed by haul roads exceeds the area included in the mining operation. Studies (2 and 3) of the U. S. Forest Service in eastern Kentucky show that typical contour mining roads exhibit poor alignment, excessive grades, insufficient strength and durability, and poor drainage. Mine roads in other Appalachian- States, particularly where contour mining is practiced, appear much the same as those in Kentucky. Access roads(4) were also found to be a large source of sediment. It is possible that of the sediment that finds its way into the streams as much (or even more) originates from the haul roads as from the mining operation. Most roads are built as cheaply as possible, and good road-building design and practice are ignored. Maintenance schedules are generally inadequate, and upon completion of mining, haul roads are usually abandoned, with little or no attempt made to bed them down(5 ) . Such roads deteriorate very rapidly (Figure 68). Area mining, which is practiced in flat to gently rolling terrain, presents fewer haul road related environmental problems. These roads through necessity are generally well engineered because of the heavy equipment using them, such as 240 ton (217 metric ton) haul trucks. They must have wide beds, good alignment, and adequate drainage to permit coal haulers to run at top speed during all seasons of the year. Excessive dust can be a public nuisance and a driving hazard, and it is hard on equipment. Calcium chloride and sodium chloride have proven to be effective materials for controlling dust. Two applications during the summer when the ground surface is moist at the rate of 1/2 pound per square yard (.26 kilograms per square meter) (3 1 have been suggested. Th4 most common procedure is to keep the roads wet by using water trucks. Sediment that reaches the streams can be traced to one or more of the following five basic phases of haul-road life:

Jan 1, 1974

By J. R. Hoskins

A recent survey of 23 vein-type metal mining operations in several western states discloses that some of the more serious deficiencies in ventilation technology are associated with inordinately high levels of mine resistance. This problem has progressively increased over many years of operation (without adequate remedial action) as mines have become extended in depth. Where two shafts form the downcast and upcast airways of a relatively deep mine, the whole of the mine air volume must pass through each shaft in turn. Since at least one of these shafts contains hoisting equipment, structural members are necessary to support the rigid guides and shaft walls. These offer high aerodynamic resistance. In some deep mines, a single shaft of this nature may represent upwards of one-half of the total mine resistance. The second shaft, depending upon its design, may represent an additional one-third of the mine resistance. Therefore, the various working levels throughout the mine contribute only the small remaining amount of the total mine resistance.

Jan 1, 1972

In the interest of safety in metal mining, the Bureau of Mines recommends: That underground metal mines be equipped with a main fan in a fireproof housing, located preferably on the surface. The fan installation should be designed to ventilate the mine adequately throughout and to permit prompt reversal of direction of air flow. Many metal mines depend for ventilation upon natural flow of air, assisted by the exhaust from pneumatic drills and by compressed air blown into the workings. Others also ventilate separate headings or sections with fans and blowers. Relatively few have o mechanical ventilating system that controls the coursing of air throughout the mine.

Jan 1, 1939

By Noel N. Moebs

Studies by the Bureau of Mines have identified geologic structures in mine roof rock that contribute to many roof falls in Appalachian coal mines. These structures, including paleochannels, scours, pinchouts, slickensides, clay veins, crevasse splays, and joints, can often be identified during, and sometimes before, mine development. Mine projections can be revised to reduce the adverse effects of discontinuitites in roof structure; large roof areas of laminated sandstone or incompetent strata generally can be delineated or inferred from exploratory drill hole data, and the need for supplementary support can be anticipated. Accurate descriptions of roof geology also provide some indication of optimum length and type of roof bolts that should be installed.

Jan 1, 1981

By Oliver C. Ralston

Fluorescence is of growing interest to the mineral industry because certain minerals may be detected thereby and because, as shown in figure 1,4/ many minerals (natural or synthetic) are needed in tubes and lamps. The use of fluorescent lighting is expanding, and large numbers of lamps of many sizes and shapes are being made and used in works, factories, stores, offices, homes, and in photography. Fluorescent tubes, as distinguished from clear tubes filled with neon, argon, or other rare gases through which a current of electricity passes, fluoresce owing to specially, selected and prepared minerals placed in the tubes. Luminous chemicals and paints also contain special minerals and are used in similar applications; therefore, these also will be considered in this report. Although the quantity of minerals (in tons) that are used for fluorescent purposes is small, and probably will continue to be so, this use is significant because it exemplifies a requirement for "pure" minerals in which a trace of contaminant as" minute" as one part in ten million may distinguish between the acceptance or rejection of a particular material. This extreme purity makes synthetic minerals almost essential, and natural mineral's are now little used.

Jan 1, 1944

By A. D. Garman

This paper presents one of a series of digests of foreign mining legislation and court decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the laws of Uruguay has been prepared from the best available information in Washington, but is released subject to correction and amplification , if necessary , by the proper American diplomatic and consular officers to whom it is being referred through the courtesy of the Department of State .

Sep 1, 1930

By I. L. Nichols

Volatilization of cesium from pollucite ore was investigated as an initial step in the production of purified cesium metal or cesium salts. High recovery of cesium and rubidium as chloride sublimates was accomplished by 2-hour roasts in a tube furnace using charges containing 1 part ore, 2 parts limestone, and 0.23 part calcium chloride. Recoveries of cesium in the sublimate product were 89.1, 92.9, and 95.2 pct, respectively, using 1,100° C and vacuum, 1,250° C with an air sweep, and 1,250° C without an air sweep. Most of the lithium, sodium, and potassium sublimed with the cesium and rubidium, but virtually none of the calcium, aluminum, and silicon in the charges was volatilized.

Jan 1, 1966

By W. E. Wells

This report describes experimental investigations made in the batchwise retorting of Colorado oil shale. Three heat-carrying mediums were used -hot shale gas, superheated steam, and hot flue gas. Using hot Shale gas for retorting, the several variables studied were retort-inlet-gas temperature, gas velocity through the shale bed, shale particle size, and grade of shale. In studying the effect of any one of these variables on oil yield, as and operability, the other variables were maintained essentially constant. Oil yields decreased with increasing in-let-gas temperature and increasing shale-particle size, and oil yield increased with increasing grade of Shale up to 50 gallons of oil per ton of shale, beyond which the process was inoperable because of swelling and caking of the shale during retorting. Changes in gas velocity had little effect on oil yield. Gas yield increased with increasing inlet-gas temperature, gas velocity, particle size, and shale grade. Oil yields of 100 percent of Fischer assay and from 1,600 to 1,800 cubic feet of 300-B.t.u. gas per ton of shale were obtained. Two runs only were made using superheated steam. Oil yields averaged 97 percent of Fischer assay, and gas yields averaged 4,00o cubic feet per ton of shale. Retorting with a hot flue gas produced from combustion in the shale bed, as in the N-T-U process, gave excellent yields using closely sized shale with recycling of flue gas. An excess of fine shale in the charge resulted in channeling and low oil yields. Using no recycle gas, good yields were obtained that tended to decrease with increasing air rate, and the retorting rate increased with increasing air rate over the range studied. Coking was not found serious with 30-gallon shale at the air rates used.

Jan 1, 1952

By Peter J. Clarke

Development of the mineral and energy resources of Afghanistan appeared to be a top priority of the Soviet-controlled Government in the country. In the Afghan Government's plan for 1980-81, the largest allocation in the development budget was for mines, industry, and energy (46.7%). In contrast, only 23.1% of the budget was allocated for agricultural development, despite the fact that the great majority of the population was dependent on farming. The mineral industry of Afghanistan consisted of the production of natural gas, cement, coal, fertilizer materials, and rock salt. Production levels for all of these commodities were down an average of 45% from those of 1978, before the Soviet invasion. Prior to the invasion, small quantities of asbestos, barite, and talc had been produced along with about 6,000 to 7,000 kilograms per year of lapis lazuli, a semiprecious gem stone. Afghanistan had supplied about 80% of the world's output of lapis lazuli. Following direct Soviet intervention, production of these minerals declined to near zero.

Jan 1, 1983

By C. M. Frost

The hydrodesulfurization characteristics of a residual fuel prepared from Wilmington, Calif., crude oil were determined at temperatures from 600° to 900° F, pressures of 200 to 800 pSig, and space velocities from 0.2 to 2.0 Vo/Vc/hr, using cobalt molybdate type catalysts. A prediction equation, developed from the experimental data, satisfactorily predicts the fraction of total sulfur that can be removed under any combination of operating conditions within the ranges investigated. Yields and properties of the low sulfur product are correlated with the fraction of total sulfur removed. Kinetic calculations show that the apparent reaction order and activation energy change with space velocity and temperature.

Jan 1, 1970

By James V. Luxner

The airflow and methane distribution patterns developed in an equipment-free entry 6.5 feet high and 12 feet wide, ventilated by line brattice operated blowing to or exhausting from the face, were determined by the Bureau of Mines for varying conditions. Results of these studies show that blowing line brattice systems of face ventilation are more effective than comparable exhaust systems. The face ventilating efficiency of any line brattice system is dependent upon the method of ventilation, the face distance, the tight rib distance, the volume of air delivered to the end of the line brattice, and the volume of methane released at the face. Experimental results indicate that maximum face ventilation efficiency is achieved when the inby terminus of the line brattice is installed 5 feet from the face and at a distance less than one-third the entry width from the nearest rib. Analyses of data are based upon the ability of a face ventilation system to dilute methane in the immediate face area.

Jan 1, 1969

This volume contains a series of papers describing research conducted by the Bureau of Mines to develop or improve equipment and systems that satisfy the communication requirements of miners doing work related to rail, belt-conveyor, trackless, and hoist haulage systems.

Jan 1, 1977

By David S. Yantek

A-weighted sound levels around vibrating screens in coal preparation plants often exceed 90 dB(A). The National Institute for Occupational Safety and Health (NIOSH) is actively developing noise controls to reduce noise generated by horizontal vibrating screens. A 121-microphone, 3.5-meter-diameter array was used to perform beamforming to determine locations of significant noise radiation on the screen. Below about 1 kHz, the screen body was found to be the most significant noise source. The beamforming contour maps showed several key locations on the sides of the screen and the feedbox are the most significant contributors. Operating deflection shape (ODS) analysis was used to examine the screen behavior under actual operating conditions. This information is helpful in determining how to modify the screen body to reduce the noise radiated by the screen below 1 kHz. The analysis showed modal vibration patterns on the sides and feed box were the main contributors to noise. The results show several areas on the screen sides and feedbox that can be modified to reduce noise.

Jan 1, 2009

By Manuel Gomez

Carbon number distributions were obtained for tar acid fractions from five low-temperature tars by low-ionizing voltage mass spectrometry. Quantitative data for phenols representing seven structural compound types were examined by statistical analysis. It was shown that for the phenols discussed, the data could be represented by regression equations expressing phenolic concentration as a function of the reciprocal of the carbon number and the carbon-to-hydrogen ratio of the parent coal. The total concentration of each structural type present was found to depend on the molecular weight and boiling point of the initial member of the group. Carbon distribution data for the tar acid fractions studied support the view that low-temperature tars contain the same chemical compounds but in different proportions.

Jan 1, 1965

By Van E. Shaw, D. J. Bauer

Conversion of euxenite concentrate to sulfates with sulfuric acid and solvent extraction of the yttrium- rare - earth mixture with EHPA were studied to determine extraction and separation characteristics . Digestion with 3.5 pounds of 96 percent sulfuric acid per pound of concentrate at 336 ° C for 4 hours resulted in an easily handled product with a yield in excess of 98 per- A thorium- free product was obtained by calcining the sulfated material for 3.5 hours at 650 ° C prior to leaching with water . Di ( 2 - ethylhexyl ) phosphoric acid solvent is an effective extractant with preference for cerium ( IV ) and heavy - group rare - earth elements including yttrium . Separation of complex rare - earth mixtures into light- and heavy - group fractions is feasible , and these fractions can be further processed to isolate ytterbium , neodymium , and dysprosium by changing processing conditions to obtain separation factors greater than two between these and adjacent elements .

Jan 1, 1965

By D. B. Taliaferro

Information regarding the pores or voids in reservoir rocks is vitally important in the scientific extraction of petroleum from natural underground reservoirs, and petroleum technologists concerned, with subsurface, conditions have devised various methods that give reasonably accurate information as to the porosities of oil and gas-bearing sands.5/ In this, work, several investigators have made use of the experience of the ceramic and other industries. The method of determining the effective porosity of oil sands described in this report falls within the general classification of gas-expansion methods. It was devised and developed at the United States Bureau of Mines Petroleum Experiment Station, Bartlesville, Okla., as a part of the research dealing with fluid and energy relations in reservoirs and improved oil-recovery methods. The apparatus and procedure are well adapted to the requirements of the Bureau, and the following detailed description has been prepared so that others may make use of the information. A tabulation at the end of the report gives the results of several hundred porosity determinations for oil sands in fields of 11 States.

Jan 1, 1937

By D. B. Taliaferro

Information regarding the pores or voids in reservoir rocks is vitally important in the scientific extraction of petroleum from natural underground reservoirs, and petroleum technologists concerned. with subsurface conditions have devised various methods that give reasonably accurate information as to the porosities of oil and gas-bearing sands.5/ In this work, several investigators have made use of the experience of the ceramic and other industries. The method of determining the effective porosity of oil sands described in this report falls within the general classification of gas-expansion methods. It was devised and developed at the United States Bureau of Mines Petroleum Experiment Station, Bartlesville, Okla., as a part of the research dealing with fluid and energy relations in reservoirs and improved oil-recovery methods. The apparatus and procedure are well adapted to the requirements of the Bureau, and the following detailed description has been prepared so that others may make use of the information. A tabulation at the end of the report gives the results of several hundred porosity determinations for oil sands in fields of 11 States.

Jan 1, 1937