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By J. A. Cavallaro

The heats of formation of anhydrous barium carbonate (witherite), strontium carbonate (strontianite), and lead carbonate (cerussite) were determined by solution calorimetry. The solution mediums were hydrochloric acid for barium and strontium carbonates and perchloric acid for lead carbonate. The heats of formation at 298.15° K are as follows: BaCO3 -297.5 ± 0.8 kcal/mole; SrCO3 -294.6 ± 0.5 kcal/mole; and PbCO3 -168.0 ± 0.3 kcal/mole.

Jan 1, 1966

By R. M. Gammell, S. H. Lorain

The Anderson prospect is one of a number of properties investigated by the Bureau of Mines during the course of preliminary studies of the lead-zinc districts of northern Stevens County, Washington. examined by W. R. Green, an engineer of the Bureau of Mines, in June 1944. This examination was supplemented in late 1944 and the spring of 1945 by pre- The property was first liminary angle-dozer trenching and core-drilling. A second examination of the property was made by the junior author in November 1945. The data obtained in the course of these studies is presented in the following report.

Mar 1, 1947

By J. M. Kuchta

Experimental data are presented on the autoignition temperature (AIT) characteristics of the hydrocarbon jet fuel, JP-6, in various oxygen-nitrogen atmospheres under conditions of constant volume and constant pressure. AIT's of this fuel in air varied little with fuel injection pressure but increased greatly with decreasing fuel content at low fuel-air-ratios. They also increased with decreasing oxygen content of the fuel vapor-oxidant atmosphere. Consistent with thermal ignition theory, the ignition temperatures increased with decreasing initial pressure, ignition delay, and vessel radius; expressions are given which define the observed variation of AIT with these variables for JP-6 fuel vapor-air mixtures. The significance of autoignition temperature data obtained using various ignition criteria is discussed to show the usefulness of such data in evaluating fire and explosion hazards. In addition, data are presented on the extent of oxidation that occurs prior to autoignition of this fuel in air at various temperatures.

Jan 1, 1965

By Larry G. Stolarczyk

This report deals with information regarding a new Medium Frequency (MF) Wireless Communication System for underground mines. This new telecommunication system works on low loss electromagnetic wave propagation modes which allow it to provide quality radio communications almost anywhere in a mine. Tests show the MF system can provide improved safety and managerial control, increased productivity, better organizational team-work and reduced maintenance cost; furthermore, MF's unique design allows for easy installation at a minimum cost. This paper covers the following: 1) MF design plan, 2) Overview of mine radio communications systems, 3) Preparations needed for designing an MF system, 4) MF equipment, 5) MF installation, 6) MF design considerations, 7) MF design specifica¬tions, and 8) Recommendations dealing with MF system. Experiments in four mines are illustrated to demonstrate the success and via¬bility of the MF system. The mines range from small (500 tons/day) to large (67,000 tons/day) capacity and represent several different mining methods. The MF Wireless Communication System represents an advancement in mining communication and the groundwork for other advanced mine systems.

Jan 9, 1984

By Sidney Katell

Continuing the series of cost bibliographies which was initiated with the publication of Information Circular 7516 in October 1949, the present report covers the period from January 1959 through December 1959. The abstracted articles, concerned with all facets of cost engineering in the field of petroleum and chemical plants and related facilities, were obtained from the following sources: 1. Bureau of Mines Information Circulars. 2. Bureau of Mines Report of Investigations. 3. Chemical Engineering. 4. Chemical Engineering Progress. 5. Chemical Week. 6. Coal Age. 7. Coal Utilization. 8. Cost Engineering. 9. Industrial and Engineering Chemistry. 10. Nucleonics. 11. Oil and Gas Journal. 12. Petroleum Engineering. 13. Petroleum Refiner. 14. World Oil. On Oct. 16, 1959 a cooperative agreement between the Bureau of Mines and the American Association of Cost Engineers became effective. This agreement provides for the publication of the annual bibliography under the sponsorship of both groups with the work load involved in the preparation divided equally between the two. As a result, the present report partially reflects the efforts of the members of the Association.

Jan 1, 1960

By Robert H. Merrill

This report summarizes the first phase of studies to determine the design and behavior of an unsupported roof in an experimental room in limestone. The selection of a roof horizon and the design of the room were results of an investigation of the geology of the formation, the physical properties of samples from the proposed roof, and calculations from the theory of gravity-loaded beams. The design of the opening, some physical properties of the roof in place, and the behavior of the roof were checked by tests in a full-scale experimental room. The room was instrumented to measure roof deflection, separations in the roof strata, and incipient failure. The dimensions of the room before instrumentation was installed were 10 by 100 feet; the room was widened in successive increments to 40 by 100 feet. Between widening operations periods up to 6 months were allowed to provide a time test of the roof spans. The results of the measurements of deflection and separations showed that the lowest 6-inch layer in the roof became detached as the room was widened. This layer was eventually removed after standing without failure for about 4 months at room dimensions of 40 by 100 feet.

Jan 1, 1957

By Roger J. Morrell

Disk-cutter experiments were performed on five rock types ranging in compressive strength from 9,000 psi to 27,000 psi. A specially constructed testing machine called a linear-cutter apparatus (LCA) was designed to load and traverse a free-rolling disk cutter across a sawed rock surface. The LCA was instrumented to measure the vertical and horizontal forces acting on the cutter during the run.. The ability of disk cutters to fragment rock was determined for both 60--degree and 90-degree cutting-edge angles, and relationships and regression equations were developed to predict cutter performance based on rock physical properties and applied forces,

Jan 1, 1970

By E. J. Lintner

This paper is one of a series being prepared by the United States Bureau of Mines describing clay mining and crushing methods and costs at various operations throughout the United States. These papers are designed to disseminate technical information regarding methods used. The cost tabulations represent local operating expenditures only and not total production costs. It is recognized that publication of total production costs might, in many instances, cause embarrassment to the individual operator as well as to the industry as a whole. On the other hand, operating costs are essential to a technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations may ensue. The author wishes to acknowledge the assistance of the following persons: L. W. Camp, general manager; S. Cooper, plant superintendent; and W. R. Riel, office manager.

Jan 1, 1936

By A. L. Engel

The Bagdad-Chase copper-gold mine south of Ludlow, Calif., was visited by an engineer of the Bureau of Mines in July 1955 to determine the mine's status of activity and to obtain a bulk sample for metallurgical testing. The deposit was discovered in 1903 and has been worked intermittently. It has a production record of about 273,000 tons of ore. The first production of about 150,000 tons was treated in a cyanide plant 2 miles west of Barstow, Calif. The extraction of gold was not satisfactory because of the presence of copper minerals. Since 1910 the ore has been shipped to various smelters in Arizona and California for use as a flux.

Jan 1, 1957

By Ralph L. Windrow

This paper is one of a series being prepared for and published by the United States Bureau of Mines describing methods and costs of mining and preparing sand and gravel for market at various plants throughout the United States. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total costs. It is recognized that publication of total costs might in many instances cause embarrassment to individual producers as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue. The Clowdy plant, with which this paper deals, is located 7 miles west of Dallas, Tex., and has a rail connection with the Texas and Pacific Railway. In addition to the rail outlet there is a paved road over which materials produced at this plant can be moved into Dallas by truck.

Jan 1, 1932

By Robert M. Cox

The U. S. Bureau of Mines (USBM) MULSIM/NL modeling technique has been used to analyze anticipated stress distributions for a proposed alternative longwall gate road design for a western Colorado coal mine. The model analyses indicated that the alternative gate road design would reduce stresses in the tailgate entry without increasing stresses in the headgate entry. To test the validity of the alternative gate road design under actual mining conditions, a test section of the alternative system was incorporated into a subsequent set of gate roads developed at the mine. The alternative gate road test section was instrumented with borehole pressure cells, as part of an ongoing USBM research project, to monitor ground pressure changes as longwall mining progressed. During the excavation of the adjacent longwall panels, the behavior of the alternative gate road system was monitored continuously using the USBM computer-assisted Ground Control Management System. During these field tests, the alternative gate road system was first monitored and evaluated as a headgate, and later monitored and evaluated as a tailgate. The results of the field tests confirmed the validity of using the MULSIM/NL modeling technique to evaluate mine designs.

Jan 1, 2010

By Jack E. Tress

The Bureau of Mines has been involved for several years in the development of processes for the recycling of solid wastes. As part of this program, a project was initiated to determine the feasibility of producing secondary pig iron from auto scrap. During the test period, 86,000 pounds of shredded auto scrap, along with petroleum coke and fluxing agents, was charged to a submerged-arc furnace of 1-ton nominal capacity. Eighty-eight thousand pounds of pig iron, with an average carbon content of 3.90 percent and an average copper content of 0.2 percent, was produced at an electrical consumption of 512 kW-hr per net ton. A cost estimate of the process showed that the pig, iron might be produced at a cost of $57 per ton.

Jan 1, 1973

By Oliver Bowles

"Introduction.During recent months the Bureau of Mines has conducted a detailed study of the slate industry with special reference to increased efficiency in its production, preparation and utilization. The results of these investigations will be incorporated in a forthcoming bulletin. The purpose of this preliminary paper is three-fold. One object is to bring to the attention of slate producers certain modifications in manufacture and classification which would encourage a wider use of slate. A second purpose is to direct the thought of roofers toward the importance of proper laying of slate, and the third object is to acquaint the general public with its enduring qualities.Origin and character.Without entering into any detailed discussion of the origin and history of slate, a subject to be covered in the bulletin mentioned, it may be of interest to the general reader to know that slate is originally formed from mud or soft clay, carried down by streams and laid down in successive layers in deep water. The pressure of superimposed materials gradually compresses the clay into a firm rock known as shale. In many places this shale was, during the succeeding ages, subjected to intense pressure and folding due to mountain-building forces within the earth. This intense pressure, together with high temperature, changed the clay into other minerals such as mica, chlorite, and silica, which are very resistant to weathering, and also developed a very definite cleavage or splitting direction which characterizes the rock as slate. It is this property which renders slate of value for roofing, for, by using a broad chisel and a wooden mallet, a slate worker can readily split it into thin sheets which are later trimmed into rectangles of various sizes."

Jul 1, 1921

Provide reasonably priced, reliable fire protection for loading shovels. Approach An automatic fire, sensing and suppression system using both dry chemical and Halon 1301 was developed. It is more rugged than similar industrial-type fire protection systems. How It Works Temperature sensors detect heat from a fire, and trigger the system. These sensors are located inside the machinery house and under the house and shovel frame where it rotates around the crawler chassis ring gear. An alarm is sounded, and extinguishing agents are released either in the machinery house or in the ring gear area. The system can also be triggered by a manual control. If the fire Is detected in the machinery house, all power is shut down to the motor-generator sets, ventilation fan, and all electrical controls. Doors are automatically closed. After a delay to allow time for the ventilation fan to stop, Halon 1301, a gaseous fire extinguishing agent, is released inside the machinery house until it reaches a concentration of about 7 percent. This concentration is sufficient to extinguish a fire, but isn't toxic to personnel

Jan 1, 1980

By Benjamin W. Haynes

Materials from phosphate rock mining and processing were analyzed for fluorine and uranium content as part of the Bureau of Mines program to more effectively recover resources from mining and mineral processing reject materials. The analysis of both feed and waste materials generated in the beneficiation and acidulation of phosphate rock was performed to obtain information on the disposition and concentration of these elements in phosphate rock processing streams. Fluorine was determined by a distillation-titration method and by ion chromatography. Uranium was determined by the dibenzoylmethane (DBM) method, the reliability being confirmed by roundrobin analysis of samples within Bureau of Mines research centers. National Bureau of Standards (NBS) Standard Reference Material (SRM) 120b-Phosphate Rock was also analyzed for fluorine and uranium to verify procedures and results. Fluorine values ranged from 0.3 wt-pct in gypsum filter cake to 3.7 wt-pct in phosphate rock concentrate. Uranium ranged from less than 5 µg/g in gypsum filter cake to 200 µg/g in a dried clay slime.

Jan 1, 1981

Develop a dry dust collector suitable for working faces and belt transfer paints. Approach A filter cartridge with a reverse-pulse, self-cleaning system has been mounted in-to a low profile unit requiring electric power only. How It Works Dust-laden air entering the in-let end of the collector passes through the two inline filter elements. When the elements load to a pre-selected pres-sure drop, they are automatically pulse-cleaned by a "backflush" method using compressed air. When the elements are pulse-cleaned, caked dust material on the filter surface is released, and falls away as lumps. Dust is removed from the collector by an auger mechanism. Features of the collector are: (1) unit is completely self-contained, (2) built-in air compressor for pulse-cleaning, (3) cleaning cycle initiates automatically at a preset restriction, (4) automatic auger discharge of collected dust, (5) detachable extension auger for transporting collected dust, (6) "dust leak" indicator light, and (7) "change filter element II warning light. The collector has been designed as permissible although approval has not yet been granted.

Jan 1, 1981

By B. J. Scheiner

The Bureau of Mines investigated an electrolytic technique for oxidizing ore slurried with brine to determine its effectiveness in extracting mercury from ores. Optimization experiments conducted on a 2.5-pound-mercury-per-ton ore resulted in 95 percent mercury extraction with operating conditions of 30° C, a current density of 0.5 ampere per square inch, and a treatment time of 3.5 hours. Corresponding power consumption amounted to 38 kilowatt-hours per ton of ore treated. Amenability experiments conducted on 62 different mercury ores resulted in 90 to 99 percent mercury dissolution from ores containing 0.6 to 20 pounds of mercury per ton of ore, Treatment time ranged from 1 to 7 hours in 4-to 20-percent sodium chloride solutions, and power consumption was in the range of 10 to 50 kilowatt-hours per ton of ore. Pilot mill experiments in a 100-to 200-pound-per-hour extraction plant have been in progress to quantify power and reagent requirements. These data will be reported in a subsequent publication.

Jan 1, 1973

Reduce respirable dust in coal preparation plants. Approach Survey a representative sample of coal preparation plants to (1) determine the dust problem extent, and (2) evaluate practical dust control techniques. Coal Preparation Plant Survey Results Of the approximately 500 coal preparation plants in the United States, 18 plants in six States were randomly selected for survey. The raw hourly capacities ranged from 250 to 1,250 tons, plant construction dates ranged from 1037 to 1982, and usually 3 to 10 workers were required per shift. Respirable dust concentrations within the plants surveyed ranged from very good (less than 1 mg/m') to very poor (14 mg/m3). No relationship was found between dust concentration and age or capacity of the plant. Six of the plants had long-term respirable dust concentrations between 7 and 14 mg/m' in specific areas; six had concentrations between 2.2 and 6.2 mg/m'. Except fur ventilation, only 4 of the 18 plants used operating dust control devices with mixed effectiveness.

Jan 1, 1989

By H. P. LeVan

Research was conducted to examine the feasibility of extracting manganese from Georgia umber ore by a three-stage continuous sulfuric acid-ferrous sulfate pickle liquor leaching process. A continuous cyclic process for treating the umber was operated successfully, using a synthetic solution simulating a ferrous sulfate fortified anolyte solution discharged from a manganese electrolytic cell as the leaching medium. Leaching efficiency based on removal of the manganese from the ore ranged from 83 to 89 percent for all systems tested.

Jan 1, 1965

By Robert E. Meredith, Thomas T. Campbell

An investigation was undertaken to examine the feasibility of employing low- temperature nonaqueous baths for electrodepositing some of the refractory metals of the ferroalloy group . To date , such metals as tungsten , molybdenum , and vanadium have been produced only by high - temperature processes that are technically difficult and sometimes cumbersome in operation . Deposition studies were performed in a wide variety of organic solvents , including amides , ammonia derivatives , ketones , polyhydroxy alcohols , and ethers . Compounds prepared and used as solutes included the chloride and bromide salts of vanadium , tungsten , and molybdenum . Studies were conducted over a temperature range of 20 ° to 200 ° C under inert atmosphere . Conductivity and current potential data were obtained for all baths that contained reasonable solute concentrations . Qualitative solubility data were obtained for compounds of ferroalloy metals in a variety of solvents . In general , all solutes showed low solubility in ethers and ketones but reasonable solubility ( in excess of 20 grams per liter ) in alcohols , amides , and ammonia derivatives . No successful metallic deposits that would encourage further study were obtained with any of the systems that were examined .

Jan 1, 1963