Search Documents

By R. K. Koch

The Bureau of Mines developed a zircon sand molding process for static casting of small titanium or zirconium shapes. Castings with unfinished weights up to 3.5 kg (7.7 lb) were produced in an inductoslag furnace and castings up to 7 kg (15.4 lb) were poured in a consumable electrode skull-casting furnace. Molds and cores were made by ram-molding, foundry-grade zircon sand (AFS gfn 93 to 95) bonded by grade D waterglass and tempered with water. Molds and cores were cured either at 250° C (482° F) or 900° C (1,652° F). Castings from the higher temperature molds broke cleanly from the sand while the lower temperature molds produced castings that had to be cleaned by sand-blasting. However, low-temperature cured molds and cores have a number of advantages as follows: (1) A faster, less energy-consuming curing cycle is used; (2) expended cores are water soluble which greatly facilitates core removal; and (3) enough of the binder in crushed expended molds is reactivated by temper water so that the molding mix can be reused five times without any fresh binder additions and up to twenty times without exceeding a total cumulative binder addition of 52 ml/kg dry sand. Crushed used molds that had been cured at 900° C had no detectable binding strength when mixed only with temper water. A large number of oxide and silicate mold washes were studied for improved casting integrity. The most effective wash found for zirconium or titanium casting was monoclinic zirconia (325 mesh).

Jan 1, 1977

By Robert D. Thomson

Sheet mica is an important material in the manufacture of electronic and electrical equipment. Large quantities are consumed each year as an essential component in generators, transformers, radios, television sets, radar, electric lighting equipment, and electrical appliances. The nature, structural imperfections, and impurities determine to a great degree the usefulness of sheet mica. Proper processing and classification add greatly to its market value. This report is designed to assist producers in understanding the complexities of marketing muscovite sheet mica. ACKNOWLEDGMENTS Special acknowledgment is due S. A. Montague, of Spruce Pine Mica Co. and G. A. Purcell, mica consultant, General Services Administration, for their critical review and many helpful suggestions in the preparation of thin report. Assistance from other industry and Government representatives is acknowledged with thanks.

Jan 1, 1955

By D. N. Tallman

The electrokinetic properties of MgO have been utilized to simultaneously filter suspended solids and remove trace amounts of dissolved heavy metals from synthetic mine water. Greater than 95 pct removal of metals from influent at neutral pH containing 1 to 6 mg/L of dissolved Cd, Cu, Mn, Ni, and Zn can be routinely achieved by filtering through a granular bed of MgO at flow rates typical of rapid sand filtration (0.3 cm/s). Filtrate concentrations of most metals can be maintained below 0.1 mg/L for 160 bed volumes or more loading. The more mobile metals (those with larger solubility products) are more difficult to remove, and are strongly bonded to the MgO granules so that chemical stripping with chelating agent is required to clean the bed. Less mobile ions are easily removed by the filter and are effectively stripped by conventional filter backwashing. The fraction of metals recovered by chemically stripping the loaded MgO filters correlates to the zero points of charge of the metals. This process may be applicable to removal and recovery of trace amounts of heavy metals in mine drainage that is partly neutralized by liming. Also, since many of these metals are critical and strategic, the technique can be adapted not only to recycle process water from mineral and milling waste streams, but also to reclaim their metal values.

Jan 1, 1986

By Peter D. Lohn

The Bureau of Mines conducted both laboratory and field investigations to study the effectiveness of medium-pressure (up to 30,000 psi) water jets in controlling the generation of airborne respirable dust during the hydraulic fragmentation of coal. Laboratory studies were conducted at the Farmington High Energy Test Site of the Twin Cities Mining Research Center, and field studies were carried out at the Humphrey No. 7 mine, Mount Morris, Pa., in the Pittsburgh coalbed. The water jets were produced by commercially available triplex pumps. The dust samples were collected by midget impinger samplers, and analyzed by electronic and optical counting techniques. Respirable dust concentration for a full-scale production model was projected at below 2 mg/m3, the maximum exposure allowed by the Federal Coal Mine Health and Safety Act of 1969.

Jan 1, 1975

By Howard C. Turnage, Dana T. Updyke, Wayne C. Muhler

The objective of this project was to develop technical data and evaluate performance and utility of leaky feeder communications systems currently used in North American underground mines. The desired information was obtained principally through on-site surveys. Altogether, six of the seven mining companies known to be using leaky feeder communications were visited. This report covers the findings of these surveys. In addition, the report provides a brief background summary of mine communications, a technical discussion of leaky feeder systems, and conclusions and recommendations based on the results of the survey.

Jan 6, 1980

By H. B. Hill

The discovery of the Oklahoma City field and its .rapid development into one of the major oil-producing districts is an outstanding epoch in the history of the petroleum industry not only of .Oklahoma but also of the United States. The relatively great depth to which the wells were drilled and the large initial production of high-gravity oil are of special significance. The field has boon under proration almost from the time that its development began, and many new production problems have developed out of the changed conditions of operation. The discovery well was first tested in December 1928 at a depth of 6,402 feet, with an initial production of 4,847 barrels of 38.5° A.P.I. gravity and several months later was completed at a depth of 6,624 feet. The large initial production, the high pressure, and the large gas volume in the different horizons of the discovery well suggested the potential possibilities of gas and oil, production in formations of Pennsylvanian and pre-Pennsylvanian age.

Jan 1, 1933

By Edward W. Parsons

To determine in what part and to what extent creep or movement exists in an installed rock-bolt anchor and the effect of the creep or bleedoff on the tension load on a rock bolt, as well as the effect of normal mining activity on the rock-bolt load and anchor, the Bureau of Mines conducted tests in the laboratory and in two mines using four types of expansion-shell anchors, the wedge bolt, and in one mine, explosive-anchored rock bolts. Specially mounted heavy-duty springs, calibrated to obtain load readings from spring movement, were installed on the test bolts to prevent a drastic reduction in tension load caused by slipping or seating of the anchor. A dial gage, reading to 0.0001 inch, measured movement of the anchor shell against the rock and seating of the anchor wedge plug in the shell. While all bolts had electrical resistance strain gages for load reading, only readings from the laboratory tests were used because those from the field tests were erratic. The tests revealed that most load loss resulting from static loading is due to the slippage and seating of the serrations on the anchor shell into the drill-hole wall. Dynamic loading, primarily from sudden shocks from nearby blasting, and possibly from ground movement or mining activity, will cause the anchor wedge plug to seat in the anchor shell.

Jan 1, 1969

By J. A. Cavallaro

To determine whether magnetite consumption could be reduced and salable coal production increased by using froth flotation units in series with magnetic separators, the Bureau of Mines conducted laboratory froth flotation tests on primary magnetic separator effluents obtained from three coal preparation plants. Tests were performed in a standard 500-gram-capacity laboratory batch flotation cell. Oleic acid and methylisobutyl carbinol were used as the collector and frother, respectively. Magnetite recovery was comparable to that expected from secondary magnetic separation, and salable float coal recoveries of 0,8 to 7.6 tons per hour were obtainable. The economics of the proposed technique appear to be sound.

Jan 1, 1966

By George N. Aul

This report describes a method developed by the Bureau of Mines for sealing horizontal degasification holes so that they do not create a gas explosion hazard when intercepted by mining. A cement slurry is pumped into the hole through an injection pipe that extends to the back of the hole. Pumping continues until the slurry returns through the annulus to the hole collar. The hole is then shut in and the grout allowed to harden. Application of the procedure to six horizontal degasification holes at Eastern Associated Coal Corp.'s Honey Run shaft is discussed.

Jan 1, 1979

By E. D. Eastman

The basic character of the free energy r data relating to water and the oxides of carbon makes it desirable that the most representative values that can be obtained should be constantly available. The calculations of Lewis and Randall3 retain much of their of original value, but appear to require some modification in the light of more recent work. This paper has been written to incorporate the newer information and to present some estimate of the reliability of the resulting figures. The data upon which the calculations are mainly based are, for these substances, the equilibrium constants of the various reactions involved. The original work relating to these equilibria has, been reviewed and, where possible, weighted to correspond with its probable reliability. The differences in the results of the present from the earlier calculations are partly the consequence of this appraisal and partly of the inclusion of more extensive data, as will be indicated in detail in the succeeding sections.

Jan 1, 1929

By O. C. Blade

This report on the properties of motor fuels sold through service stations in the United States was made in accordance with a cooperative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. This paper is a continuation of a series made in cooperation with the Coordinating Fuel Research (CPR) Committee of the Coordinating Research Council (CRC), Inc. The first of this series of reports presented data on motor gasolines sold during the winter of 1935-36, and succeeding reports described motor gasolines sold during the summers and winters to and including the summer of 1941. No reports were made on motor gasolines sold during the winter of 1941-42 and during the summer of 1942. However, starting with the winter of 1942-43, the semiannual reports were resumed.

Jan 1, 1949

By M. J. Kovalik, D. E. Wolfson, F. Fischler

Plastometric tests were made to determine the maximum thickness of the plastic layer for different U.S. coals . The effect of test variables on the maximum thickness of the plastic layer was studied . The values for the maximum thickness of the plastic layer were found to be related to the Gieseler maximum fluidity , plastic temperature range , free swelling index , and other plastic properties of coals . Only a general relationship was observed between the plastometric parameters obtained in these tests and the coking properties of coal .

Jan 1, 1964

By Jr. Smith

To investigate the effects of flow geometry on laminar flames, studies are in progress in this laboratory employing Bunsen-type burners with rectangular cross section. Interpretation of these studies requires a determination of the flow velocity at all points of the rectangular cross section for one dimensional steady laminar flow. In addition, values of the velocity gradient at the boundary for such flows are needed in the interpretation of blow-off and flash-back studies with burners of rectangular cross section. The hydrodynamical problem of steady laminar flow of a viscous fluid in channels of rectangular cross section was solved by Stokes. His results have been quoted by Love21 and by Dryden, Murnaghan, and Bateman,§/ and they have been discussed by Boussines and by Paschoud. It may be noted that the steady laminar flow of a viscous fluid in channels of rectangular cross section constitutes a hydrodynamical analogue for the problem of the torsion of an isotropic prism of rectangular cross section.

Jan 1, 1952

By E. O. Binyon

"Corundum and andalusite were discovered in August 1944 on what is now known as the Blue Metal group of claims. The property, comprising five unpatented lode claims, is situated 20 Miles northwest of Yerington in the Buckskin Mining District, Douglas County, Nevada, An engineer of the. Bureau of nines examined the property on November 1, 1944, and recommended a small: amount of drifting and crosscutting to determine more definitely the extent and character of the ore deposit. The work that had been done by the owners was for sampling purposes only and was confined to a few small pits on the outcrop, and no effort had been made. to delimit the ore zone. Samples taken from the best surface showings were sent to the experimental station in Salt Lake City for beneficiation tests. The results of the preliminary test work appeared favorable, and upon the strength of them and the recommendations made by the Bureau, 2.5 miles of access road was approved and completed early in 1945. Exploration was started on June 24 and completed September 26, 1945.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mines resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.This paper is one of many reporting on various aspects of the Bureau of Mines program initiated in August 1939 by passage of the Strategic Minerals act, the scope of which was. greatly expanded by subsequent legislation.Some of these papers were published as war minerals reports, others as bulletins, technical papers, reports of investigations, and information circulars of the Bureau of Mines or• in, technical journals.The Bureau's program at first included separate investigations by the Mining and metallurgical Divisions, but these were consolidated under Assistant Director R. S. Dean beginning July 1, 1942. Mining and metallurgical investigations carried on in three regional organizations more closely integrated thereafter by a staff of specialists, who reviewed findings made in the field and in Bureau Laboratories, considered proposals for additional work, revised reports for publication, and served as advisors to the assistant director."

Aug 1, 1946

By Wendell R. Peters

Shallow underground voids resulting from early coal mining and other resource recovery activities over the past several decades are now being recognized as a significant cause of ground subsidence problems in developing urban areas. Uncertain knowledge of abandoned coal mines also imposes potential hazards in coal excavation operations since water inundation or the release of methane gas is a pricnipal hazard when mine excavation operations break into an abandoned mine. U.S. Army requirements for an effective method for detecting and mapping subversive man-made tunnels have resulted in a surface-operated automatic earth resistivity survey system with a digital computer data processing system. Field tests aimed at demonstrating the system performance resulted in successful detection of tunnels having depth-to-diameter ratios up to 15 to 1. Under the sponsorship of the Bureau of Mines, a similar system was designed and constructed for use in the detection of coal mine workings. This report discusses the hardware and software aspects of the system and the application of the high-resolution earth resistivity method to the survey and mapping of abandoned coal mine workings. In the field tests reported, the targets of interest were both air-filled and water-filled workings.

Jan 1, 1980

Construction workers may be exposed to hazardous dust containing crystalline silica during site preparation when drilling systems are used. The National Institute for Occupational Safety and Health (NIOSH) found that drill dust could be decreased by using wet or dry dust reduction engineering controls, enclosed cabs, and implementing a dust control program.

Jan 1, 2009

By E. K. Stanek

This report contains results of two major efforts related to electrical transients on mine electrical power systems. The first area concerns the use of digital computers to model mine electrical power systems and predict transients or duplicate field recordings of transients. Two existing general purpose circuit analysis programs were used. The first was the TRW Engineering System Simulator or TESS. The second was Electronic Circuit Analysis Program or ECAP. TESS proved to be superior to ECAP in several important characteristics, including system size limitations and modeling nonlinear elements. The second major topic covered in this report is the evaluation of commercially available surge suppression devices. These devices were found to be quite acceptable and guidelines for the selection and placement of surge suppressors were included. The final important item is a listing of the worst-case transients, from a design point of view, for ac and de utilization systems and ac distribution systems.

Jan 1, 1979

By Gary A. Kingston

Chromium resources in the United States are estimated at 1.8 million tons of recoverable chromium contained in 22.5 million tons of chromite-bearing material. Additional resource is presumed existent in large, but as yet undetermined, quantities of material containing less than 10 percent Cr203. No domestic resources are being mined presently (1969). Excluding transportation charges to domestic consuming areas, the total 1.8 million tons of chromim is estimated to be available, in ore or concentrate, at costs up to $0.64 per pound; 63 percent of the total is available under $0.11 per pound; and 38 percent under $0.08 per pound. It is judged that transportation from the resource areas to the existing market centers would add nearly $0.05 to the cost of a pound of chromium contained in ore or concentrate. Technically effective beneficiation methods have been developed for much of the known domestic resource, and further development might reduce costs of processing these materials. However, at present, domestic chromium resources are noncompetitive with foreign sources.

Jan 1, 1970

By Robert M. Becker

The evaluation of existing rock stresses from measurements of the change in diameter of a borehole that is stress relieved by overcoring has become a common practice, The stress evaluation has been generally based ,on isotropic relations whereas rock in varying degrees is anisotropic. A plane elasticity solution for a circular hole along one axis of an orthotropic medium is adapted for evaluation of in situ stress from borehole deformation measurements. A consistent triaxial testing approach for determining elastic properties of the overcore is also outlined. Comparison of isotropic with anisotropic interpretations of the state of stress show that large errors in evaluation may occur if the anisotropic character of the rock is neglected.

Jan 1, 1967

By McHenry Mosier

Diamond -drilling blast holes at Eastern Magnetite Mine C is proving economical in boundary shrinks , in removing pillars not readily accessible for percussion drilling , and in driving scraper drifts . The cost per foot drilled is greater than for percussion drilling , but savings in associated factors outweigh this handicap . The rocks drilled include trap rock and magnetite ore . The mining method is the panel , block- caving system utilizing scraper sublevel drifts instead of branch raises to convey the ore to the haulage level . Diamond -drilling blast holes was begun early in 1945. Three rigs equipped with noncoring bits are now in active operation two shifts per day . They are owned by the company , and the drill operators are paid by the day . In shrinkage stopes the drill is mounted on a horizontal bar set against opposite walls of the stope . Stoping holes are horizontal , which gives better results in blasting and requires fewer set ups . In scraper drifts the drill is mounted on a horizontal bar clamped to two columns about feet apart . Trim holes around the periphery of the drift and reliever holes are drilled 50 to 80 feet in length . A 10 - foot wedge cut drilled with a stoper is blasted in conjunction with a corresponding length of the trim holes to effect a 10 -foot advance of the full- sized drift . Recent drilling averages 97 feet per machine shift , excluding time utilized in setting up and moving the machine , hand mucking , and barring down . The feet drilled per bit at present is 417. These data represent the average for drilling in both rock (waste) and ore . Percussion drilling utilizes three types of wet drills . Detachable bits are standard . Gage changes for new bits is 1/8 inch and for reconditioned bits 1/16 inch . The life of a bit is five uses . Resharpening is on contract . A drill carriage is used in haulage headings .

Feb 1, 1948