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By Frank A. Peters

The Bayer process treating Jamaican bauxite was evaluated from an economic standpoint, using standard estimating methods and published data, to present a reference point for cost estimates for nonbauxite alumina processes. The estimated operating cost for a plant producing 1,000 tons of alumina a day is $47.96 per ton of alumina when charging $8 per ton for bauxite and $2.30 per hour for direct labor. The estimated fixed capital cost is $46 million.

Jan 1, 1966

By David K. Ingram

The development of large open surface fractures over mined-out coal longwall panels is the focus of this U.S. Bureau of Mines report. The research concentrates on defining the fractures characteristics and their controlling variables. The investigation was conducted at two mines in south-central West Virginia. All but one of the fractures are subparallel to the trend of the underlying longwall panel. One fracture is perpendicular to the trend of a longwall panel. Overall length of the fractures ranges from 60 to 900 ft. In cross section they are V-shaped, ranging from a couple of inches to 25 ft in width at the surface, but narrowing as they increase in depth. Fracture depth varies from a few inches to over 50 ft into bedrock. A vertical fracture or joint plane was observed in the bedrock at several open zones along the fractures. All of the fractures vary in elevation and do not parallel surface contours. The fractures are aligned with local joint trends, they correlate with longwall development, and they are situated in an increased tensional area over the mined out longwall panels. These observations indicate that the fractures are tensional openings along preexisting joint planes possibly triggered by longwall mining.

Jan 1, 1989

By K. J. Miller

A laboratory electrophoresis column was designed to separate pyrite from fine coal by utilizing an observed difference in the electrophoretic mobilities of the two materials in water. The apparatus worked well when tested with synthetic mixtures of coal and pyrite, but some modifications in design and procedure were necessary to provide a sharper separation. After these changes were made, the column was tested with a high-pyritic-sulfur raw coal sample. The column successfully fractionated the sample, removing not only the pyritic refuse, but a siliceous refuse as well. The invest ion demonstrated on a laboratory scale that pyrite and other impurities can be separated from fine coal by electrophoresis.

Jan 1, 1970

By Benjamin W. Haynes

Analytical procedures are described for the quantitative determination of 16 elements (As, Ba, Be, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, TI, and Zn) and 7 ionic species (NH4, C032-, CI-, F-, NO3-, P043-, SO42-), identification of major and minor mineral components, and measurement of physical properties associated with manganese nodules and nodule processing reject waste materials. Compound identification methods discussed include X-ray diffraction, infrared spectroscopy, scanning and transmission electron microscopy, selective area electron diffraction, and optical and reflected light microscopy. Methods for elemental analysis include atomic absorption spectrophotometry, inductively coupled plasma emission spectroscopy, neutron activation analysis, fluorescent X-ray spectrography, and ion chromatography. Thermal gravimetric analysis, ultraviolet-visible spectrophotometry, ion specific electrodes, and standard wet chemical procedures are briefly discussed. Physical properties determined in manganese nodule materials include grain size distribution, specific gravity, triaxial shear, permeability, maximum density, Atterberg limits, and slurry density. The results of a round-robin analysis of an ammonia process waste material and manganese nodule standards demonstrate the applicability of the discussed methods. Tests discussed for the evaluation of the waste materials for disposal options include the Environmental Protection Agency (EPA) EP toxicity test, the ASTM shake extraction test, and the U.S. Army Corps of Engineers EPA seawater elutriant test.

Jan 1, 1983

By Jr. Norman

Thermoelectric properties of depleted uranium selenides and tellurides were investigated from room temperature to 700 C. Several depleted uranium monoselenides and monotellurides were doped with selected cationic and anionic materials to determine the effect of impurity additions on the thermoelectric properties. The undoped uranium selenides and tellurides were semimetallic conductors exhibiting low Seebeck coefficients and electrical resistivities. Partial or complete degeneracy was in evidence, indicating a charge carrier energy distribution similar to that in a metal. Doping increased the Seebeck coefficients of the uranium monoselenides and monotellurides; however, the corresponding change in the power factor in the figure of merit was small because of the increase in electrical resistivity.

Jan 1, 1965

By Arthur Metcalfe, Edward Thomas, A. J. Barry

"Early in 1947 the Bureau of Mines became interested in adapting suspension roof support to coal mining 5/ as a possible means of reducing the high rate of accidents from falls of roof. For a time the program made little progress be¬cause of the shortage of steel products after the end of World War II, but during the past 8 months this restriction has eased, and as of May 1, 1949, 114 mines had either started experimental work or had ordered materials and equip¬ment in anticipation of trial installations. It is estimated that 30 linear miles of roof in underground passageways have been secured by this method in recent months, and no lost-time roof-fall accident has been reported in these areas up to that date.Many coal-mining companies in widely separated localities have cooperated in making experimental installations. In very few instances are these companies entirely satisfied that they have arrived at the best solution in determining the most efficient adaptation to suit their particular conditions. Moreover, new ideas and modifications of the basic principle are constantly being brought to light and are being tested. Available test data is far from complete, and it is conceivable that some new idea will be developed to alter the present concept of proper technique; therefore, this progress report does not attempt to answer all questions that might arise in connection with this method of roof support; it simply recounts the experience acquired to date. Consequently, few references to costs are made. Up-to-date quotations on material and equipment used in suspension roof-support installations may be obtained from numerous mine-supply companies.The authors gratefully acknowledge the cooperation of mining companies whose personnel made possible collection of the information contained in this circular: Bethlehem Collieries Corp., Barrackville, W. Va.; Berwind-White Coal Mining Co., Windber, Pa.; Consolidation Coal Co., (Ky.); Jenkins, Ky.; Consolidation Coal Co. (W. Va.), Fairmont, W.Va.; Clinchfield Coal Corp., Dante, Va.; Consolidated Coal Co., St. Louis, Mo.; Hanna Coal Co., St. Clairsville, Ohio; Missouri Portland Cement Co., Sugar Creek, Mo.; Pocahontas Fuel Corp., Pocahontas, Va.; Reppert Coal Co., Dola, W. Va.; St. Joseph Lead Co., Bonne Terre, Mo.; and Tennessee Coal, Iron, & Railroad Co., Birmingham, Ala.The fundamental theory of suspension roof supports is not new; in fact, its application in the construction of beams predates mining itself. The basic principle involved is the reinforcement of roof rock with steel rods inserted in the roof and anchored therein at points where the rock is least likely to be affected by stresses resulting from mining. Such roof supports have been used in mines for many years in widely separated localities. The St. Joseph Lead Co., operating in southeastern Missouri, apparently was the first large mining company to prove the practicability of the principle by applying it in a systematic manner for securing roof for more than 20 years (fig. 1)."

Sep 1, 1949

By T. Estelle Gardner, A. R. Taylor

Heat capacity measurements were made on sodium bromide ( NaBr ) and sodium iodide ( NaI) in the temperature ranges of 7 ° to 300 ° K and 56 ° to 300 ° K using an adiabatic calorimeter . Smooth values of heat capacity, entropy , enthalpy function , and free- energy function were calculated from the heat capacity data at 10° K intervals and at 273.15° and 298.15° K. Entropy and free energy of formation values at 298.15° K also were calculated for the two compounds using entropy values determined in this study and other data reported in the literature . The entropy values calculated at 298.15 ° K were 20.75 ± 0.06 entropy units (eu ) for sodium bromide and 23.55 ± 0.07 eu for sodium iodide .

Jan 1, 1964

By T. M. Barczak

One of the primary goals of Bureau of Mines research is to reduce the cost of coal mining by improving the efficiency of longwall supports. One method of achieving this goal is the optimization of stress distribution within the support structure, resulting in a lower overall weight, more fully stressed shield. However, before stress optimization can be initiated, load conditions must be defined that cause maximum stress in the various support components. A finite-element model of a longwall shield was used to identify these critical load conditions. These load conditions were then evaluated in the Bureau's mine roof simulator (MRS) by instrumentation of a longwall shield and measurement of strains in each of the shield components. The critical (canopy-base contact) load conditions were identified that can cause structural failure at less than rated shield (hydraulic yield) capacity. Comparisons were made between full-contact and partial-contact load conditions. Other parameters investigated included the stiffness of the contact material, changes in shield geometry, rate of load application, and effects of horizontal constraint. Conclusions were drawn regarding the structural integrity of the major shield components and potential for stress optimization.

Jan 1, 1987

By L. M. Chan, D. R. Carlson, J. H. Johnson

"This paper presents an apparatus and procedures to implement a methodology for controlling ambient air quality in a confined working environment, such as an underground mine, an underground storage area, or a tunnel. The air quality control methodology is directed at limiting the quantities of exhaust pollutants emitted by diesel-powered vehicles into the confined space by identifying vehicles that are excessive polluters. The methodology is based on tailpipe and ambient air measurements in the confined space, and the ambient air threshold limit values (TLVs) for the various diesel exhaust pollutants. The methodology consists of two computational methods; a deterioration criteria computational method to identify excessive polluting vehicles, and an engine performance computational method to determine engine performance and to provide information needed to diagnose engine faults. The methodology is designed for implementation in conjunction with a preventive maintenance program.The first part of the paper describes the mine air and tailpipe emissions measurement apparatus and techniques used to obtain data. This is followed by sections discussing the deterioration criteria and the engine performance computational methods. A section discussing some common engine emissions-related faults is also presented lastly, a proposed procedure to implement the methodology including a possible hierarchical structure for mine personnel involved to implement the procedures is presented.INTRODUCTIONDiesel-powered mining vehicles are gaining Popularity in underground coal mines and are almost universally used in underground non-coal mines due to their mobility, flexibility, and higher productivity. However, noxious gases and particulate matter in diesel engine exhaust are a concern because of the potential for being harmful to the health of miners. Diesel exhaust pollutant concentrations out the tailpipe of a mine vehicle change with time due to engine wear, inadequate maintenance, improper adjustments and other factors. This deterioration in pollutant concentrations, if not properly controlled, may adversely affect the air quality in an underground mine. To provide assurance that a clean and healthful work environment are maintained, a program is needed to identify and repair diesel engines that contribute to poor air quality. Also, earlier detection of deteriorated engines will make preventive maintenance possible, thereby eliminating further deterioration and possibly complete breakdown. Preventive maintenance also increases engine life and equipment availability in production which in turn will result in decreased operating costs."

Nov 1, 1995

By Guy A. Johnson

Despite the use of warning alarms to alert miners to the backward movement of large mining equipment, miners still are injured too frequently in backup accidents. Currently approved backup alarm technology consists of continuous sounding alarm systems. New technology has developed a warning system that initiates an alarm only if there is an object close behind the vehicle. This advancement eliminates constant exposure to the alarm because a warning is given only in case of a potential collision. Adoption of this development can improve safety and reduce damage, especially for front-end loaders (FEL's). It will also eliminate a source of nuisance noise in urban and residential areas. This Bureau of Mines report describes the general characteristics of infrared (IR) light, ultrasonic wave, and Doppler radar technology as used for backup alarms, and reviews the testing of the most promising detection devices.

Jan 1, 1986

By M. Clair Smith

This report is one of a series describing exploration, development, mining methods, and costs at United States open-pit mines; the Bureau of Mines prepares and publishes them in cooperation with the mining companies. Their purpose is to promote development and conservation of our mineral resources by disseminating technologic information on mining methods and practices at various United States mines. The exploration, development, equipment, and mining of a large, oxidized-copper ore deposit by open-pit methods, the leaching of the ore with sulfuric acid solution, and the recovery of the copper as cement copper are described herein.

Jan 1, 1958

By T. M. Ruff

The U.S. Bureau of Mines has developed a portable, inexpensive teleoperation system for mobile hard-rock mining equipment. The system was tested on a compact loader-trammer in a simulated stope. The teleoperation system includes radio remote control and computer-assisted navigation. A recent enhancement includes video cameras mounted on the machine to provide visual information to the operator. This system allows the operator to remain in a safe location while operating the machine from a distance, thus increasing both operator safety and mining productivity.

Jan 1, 2010

By D. R. Tesarik

Displacement and stress changes in cemented backfill and ore pillars at the Buick Mine, near Boss, MO, were monitored by engineers from the U.S. Bureau of Mines and The Doe Run Co., St Louis, MO. A test area in this room-and-pillar mine was backfilled to provide support when remnant ore pillars were mined. Objectives of this research were to evaluate the effect of backfill on mine stability, observe backfill conditions during pillar removal, and calibrate a numeric model to be used to design other areas of the mine. Relative vertical displacements in the backfill were measured with embedment strain gauges and vertical extensometers. Other types of instruments used were earth pressure cells (to identify loading trends in the backfill), borehole extensometers (to measure relative displacement changes in the mine roof and support pillars), and biaxial stressmeters (to measure stress changes in several support pillars and abutments). Two-and three-dimensional numeric codes were used to model the study area. With information from these codes and the installed instruments, two failed pillars were identified and rock mass properties were estimated.

Jan 1, 2010

By E. C. Pattee

A mobile spectroscopic laboratory was completed by the Bureau of Mines in 195 to provide a rapid, inexpensive means of field testing samples for beryl¬lium and other associated metals of possible commercial importance. Spectro-copes have been used in laboratories for many years in various types of research and routine analyses, but this spectroscope is probably the first mobile unit. The laboratory provides for spectroscopic, radioactivity, fluorescent, and limited chemical tests of samples. The unit has been a valuable reconnaissance tool. It has been used to search for beryllium, cesium, columbium, tantalum, rubidium, and lithium in Idaho, Washington, and Montana. Several very low grade deposits of these elements were found, and occurrences of other important elements were identified; however, none are of economic importance. The spectroscope permits the detection of elements by analysis of visible light produced when elements in a small powdered sample are volatilized in an electric arc., A total of 70 elements can be detected; 29 can be detected at or below 0.01 percent, Electric power for the arc is supplied by a gasoline motor-driven generator, Equipment is housed in an aluminum van, mounted on a 4-wheel-drive vehicle for easy maneuverability on mountain roads, A trailer with crushing, pulverizing, and splitting equipment permits the reduction of samples to a small representative pulp.

Jan 1, 1963

By Edmund Shaw

This paper is one of a series being prepared by the United states Bureau of Mines describing mining and milling methods and costs at industrial mineral plants throughout the United states. These papers are designed to disseminate technical information regarding the methods and equipment used. The cost tabulations represent operating expenditures only and not total production costs. It is recognized that publication of total production 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. P. J. Weisel, Inc., with office at La Habra and plant at Corona, Calif., is the only local company that produces sand for the Los Angeles glass factories, although silica sand for other purposes is produced in other parts of southern California and the adjacent portions of Nevada. The deposit at Corona consists of coarse sand imbedded in a whitish clay and differs greatly from the other deposits, which are fine-grained sandstone that must be crushed before it can be screened and washed. The preparation of Corona sand has to be thorough and includes grinding in tube mills, repeated washing and rinsing, removal of dust by air separation, and magnetic separation of iron and other minerals. This requires a plant with a complicated flow sheet. The first plant built did not make a. satisfactory glass sand, and many additions and changes were necessary. It is thought that the present flow sheet will remain substantially unchanged until a new plant is built. The design of a new plant would be simpler, but the process would be the same.

Jan 1, 1937

By Victor E. Kral

The Modarelli iron deposit , formerly known as the Requa iron deposit , is 44 miles by road south of Palisade , Nev . , on the Southern Pacific and Western Pacific Railroads . Construction of 10 miles of new road, which is necessary in case the property is exploited , will reduce this distance to about 28 miles . The deposit was discovered in 1905 , and patent was obtained in 1907 . The present owners obtained title to the property in recent years by paying the delinquent taxes . There has been no production . The ore deposit is a replacement of a Tertiary volcanic believed to be a rhyolite . Except for evidence of slight shearing , the deposit has no apparent structure . Hematite is the principal ore mineral ; it is fine-grained and is associated with very fine-grained apatite and unidentified minerals assumed to be alteration products of residual rhyolite minerals .

Feb 1, 1947

By Stephen P. Holt, John A. Bowsher

A preliminary examination of the mica deposits in Culberson and Hudspeth Counties , Texas , was made in September 1942 by A. B. Needham, district engineer of the Bureau of Mines . The deposits were reexamined by R. C. Redfield , associate mining engineer of the Bureau in November 1942, at which time he was accompanied by Philip S. Hoyt , geologist , and J. C. Moore , foreman of the Texas Mica and Feldspar Company . Exploratory work was started on February 16 , 1944 , and terminated on April 30 , 1944. A crew of 4 to 10 men was employed under the supervision of the authors .

Feb 1, 1947

By Paul L. Russell

Because of the increasing demand for fluorspar , investigation of the deposits of the Gila district in Grant County , New Mexico , was undertaken by the Bureau of Mines in 1943 with the cooperation of the Federal Geological Survey . It was the purpose of the investigation to assist owners and lessees to develop their properties and to attempt to estimate ore reserves that might be available to supply a 300- ton mill that was under construction at Gila . Field work was begun June 14 , 1943 , and ceased August 16 , 1943. Seven veins were trenched and sampled .

Feb 1, 1947

By H. J. Heinen

Excellent gold recovery was demonstrated in a laboratory-scale leaching test on waste material from an open-pit mine in northeastern Nevada. An injection system of leaching was applied in which the sodium cyanide solution was introduced into the interior of the dump at selected points. Dissolution of gold from the waste material, which assayed 0.06 ounce gold per ton, was readily achieved because the gold occurred as submicroscopic particles in a porous host rock. Gold recovery of 80 percent was obtained in 11 days from material crushed to 1 inch in size, and recovery was 90 percent after 21 days.

Jan 1, 1969

By H. B. Brunot, L. C. IlsLey

The design , construction, inspection , and test for permissibility of a storage- battery locomotive outfit in accordance with the requirements of Schedule 15* represents a large amount of work, first on the part of the locomotive manufacturer and secondly on the part of the Bureau of Mines . Detailed information of the first investigation under the schedule is presented here . This investigation covers the inspection and test of a storage- battery locomotive manufactured by the Geo . D. Whitcomb Co. , Rochelle , Ill . , to which Approval No. 1500 was assigned ,

Feb 1, 1923