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By R. P. Maloney

Since mining operations began in 1900, Government geologists and mining men have periodically recorded the presence of the minerals of mercury and antimony in the extensive gold placer deposits near Flat in the Iditarod district of the Yukon River region, Alaska. No serious effort was made to recover the cinnabar contained in the gold placer gravels, and there is no evidence that veins of cinnabar and stibnite exposed in the placer operations (as reported by the Geological Survey) were ever explored or developed. A large monzonitic intrusive, which is the dominant geologic feature of the immediate area, is believed to be the lode source of the valuable minerals in the placer deposits. In contact with the monzonite are argillite and quartzite, metamorphic products from the Cretaceous shales and sandstones.

Jan 1, 1962

By J. Koster

[Boron is an element whose metallurgical possibilities never have been investigated thoroughly, probably because of the difficulties experienced in the preparation of elemental boron and its intermetallic compounds. The southwestern United States contain the world's s largest deposits of boron minerals. In general, the mineral is readily available, and mining costs are not excessive. The most important boron mineral of commerce is borax (sodium tetraborate) however, there are large deposits of colemanite (a mineral having the composition represented by 2CaO 3B2O3 5H2O) in Clark County, Nov. This material was worked in times past by converting it to sodium tetraborate. In recent years the deposits have laid idle because of a mire readily available source of borax in the old lake beds of California.]

Jan 1, 1940

By Fred D. DeVanery

"INTRODUCTION Although galena is the most common lead-bearing mineral, is easily concentrated by gravity methods, and is readily susceptible to flotation, nevertheless some galena-bearing orebodies have within them small deposits of lead ore that fail to give a high recovery when treated by the customary milling methods.The secondary minerals, cerussite and anglesite, which result from natural oxidation of galena, cause losses when the customary method of lead-ore concentration is practiced. The identification of oxidized lead-ore minerals and the efficient concentration of a lead ore taken from the oxidized portion of an orebody which has previously yielded poor recoveries mere the objects of a recent investigation. Thus the ore examined was selected from a large orebody. The work was undertaken at the Mississippi Valley Experiment Station of the United States Bureau of Mines in cooperation with the Missouri School of Mines and Metallurgy, Rolla, Mo.DESCRIPTION OF OREThe ore was of a brownish color owing to oxidation of some of the iron minerals to limonite. The lead content was 6.80 percent, and a cursory examination showed that most of the lead was present as galena. Small amounts of sphalerite, siderite, and pyrite were readily identified. The chief gangue mineral was dolomite, accompanied by smaller amounts of calcite and glauconite."

Jun 1, 1933

By George Quackenbos

The principal objective of this Program is the design, fabrication and testing of an Environmental System for operation in underground mines, to assess the effect of various mining systems on the contaminant levels near the mine face and within return airways. In order to determine the effect on airborne contamination in mines resulting from the development of new mining techniques, equipment and control systems, a Comprehensive Monitoring System is required to assess such contamination levels at critical and strategic locations and relate this information with ventilation parameters. The three variables to be sensed on a continuous basis are airborne dust concentration, methane concentration and ventilation air velocity. Each Monitoring Station will consist of a self-contained unit containing a power source and sensors to monitor the three above mentioned parameters. Ruggedness, reliability, ease 'of operation and intrinsic safety are important design objectives. Data gathered by each Monitoring Station will be fed to a Central Data Acquisition System by means of a portable transfer unit.

Jan 1, 1982

By Guy E. Dent, Hugo E. Kuehn

"SUMMARYFor making a comparison of magnetic surveys measured from the ground and from the air, Worcester County, Maryland, was chosen as a proving ground. Vertical magnetic intensities were observed on the ground, and total magnetic intensities were observed from the air. A comparison of the two magnetic maps reveals similar large magnetic features, but these are displaced in some instances by distances greater than a mile. Magnetic terrane in the two charts is of the same type but often differs greatly in respective characteristic features.The sacrifices in accuracy that may be expected from the use of different systems of diurnal magnetic corrections on ground observations constitute a part of this report.INTRODUCTIONThe value of magnetic surveys for gaining information concerning the crystalline basement is recognized increasingly. That this topography is often reflected to a major degree in the overlying sediments with certain offsetting is well understood. Even where such sediments are deep, the surface topography of upper formations often reflects this bedrock topography to a certain degree."

May 1, 1947

By L. H. Wullstein

Nitrogenase activity (C2H2 reduction) was found to be associated with the following grasses in the field: Agropyron dasystachyum, Agropyron smithii, Aristida purpurea, Oryzopsis hymenoides and Stipa comata. Uptake of fixed nitrogen was also demonstrated for these grasses. Two unidentified nitrogen fixing bacteria were isolated, one from Stipa comata and one from Aristida purpurea. Cynodon dactylon and Agropyron cristatum were successfully inoculated with the unknown isolate obtained from Stipa comata. The inoculated plants exhibited nitrogenase activity (C2 H2 reduction) whereas uninoculated controls gave negative results.

Jan 1, 1982

By J. R. Ross

A reconnaissance for sources of scandium and a metallurgical investigation of recovery methods for byproduct scandium from uranium mill solutions were conducted by the Bureau of Mines. The work on scandium was undertaken to obtain information on domestic resources and to explore and develop recovery procedures in consonance with the Bureau's long-range program for conservation and wise utilization of mineral resources. The element scandium is widely distributed in the earth's crust in trace amounts, but it seldom occurs as an important constituent in any mineral. An exception is thortveitite, (Sc,Y)2 Si207) a rare mineral that contains various amounts of scandium and yttrium and may contain up to 42 percent scandium oxide (SC203). Knowledge of the chemistry of scandium has expanded rapidly in recent years (1, 4, 9)4 but only fragmentary information is available about the metal because it is still largely a laboratory curiosity without established uses (2, 3). A recent study shows some of the physical proper-ties of the metal are (1) density of 3.05 grams per cubic centimeter) (2) melting point of 1,540° C, (3) hexagonal close-packed structure) (4) hardness of about 50 Brinell (500-kilogram load), and (5) an alloy behavior similar to yttrium and rare-earth metals (2). The price of $2,850 a pound for scandium oxide of 99.9 percent purity and $2,700 a pound for oxide of 99 percent purity reflects the scarcity and complex chemistry of the element.

Jan 1, 1962

By J. Koster

Boron is an element whose metallurgical possibilities never have been investigated thoroughly, probably because of the difficulties experienced in the preparation of elemental boron and its intermetallic compounds. The southwestern United States contain the world's largest deposits of boron minerals. In general, the mineral is readily available, and mining costs are not excessive. The most important boron mineral of commerce is borax (sodium tetraborate); however, there are large deposits of colemanite (a mineral having the composition represented by 2CaO 3B203 5H20) in Clark County, Nov. This material was worked in times past by converting it to sodium tetraborate. In recent years the deposits have laid idle because of a mere readily available source of borax in the old lake beds of California.

Jan 1, 1940

By D. E. Wolfson

As part of its overall program of coal carbonization, the Bureau of Mines is studying the coking properties of coals that may be used for metallurgical purposes. The objectives of this study were given in detail in a previous report.2/ The suitability of coal for metallurgical use depends primarily on (1) chemical composition, (2) preparation characteristics, and (3) carbonization behavior. The first two factors, as well as the available reserves, are considered in selecting coals for carbonization tests. According to the estimate of reserves by Dowd,3/ the recoverable coal in Raleigh County in beds 28 inches or more thick, in thousand tons, is: [ ]

Jan 1, 1957

By E. J. Gleim

A list of permissible mine equipment, tested and approved by the Bureau of Mines previous to January 1, 1942, was published in Bureau of Mines Information Circular 7207.3/ The list of that date was complete as to equipment then available and in current use. Information Circular 7240,4/ published as a supplement thereto, listed equipment approved curing the calendar year 1943. The present list is another supplement covering approvals issued during the calendar year 1943. The items are numbered to indicate the consecutive order in which each type of machine or device was approved in its particular classification. Thus, Information Circular 7207 gave 19 drills and drilling machines on the Bureau's active list. No additional approvals were given in 1942, but the three issued in 1943 bring the total to 22. Item 102, under Loading Machines and Conveyors, also appeared in Information Circular 7207, and items 120 and 124 appeared in Information Circular 7240. These numbers are repeated here to show that approvals were granted during 1943 for additional voltages on machines previously listed for one voltage only. Equipment listed in these circulars is approved by the Bureau of Mines only when found upon inspection and test to comply with minimum standards of safety as outlined in schedules prepared on the basis of many years of experience in dealing with safety problems of the coal-mining industry. The use of such equipment in mines known to be gassy, as well as in those that may become so, is earnestly recommended in the interests of safety. This circular is published so that the industry may be kept

Jan 1, 1944

By Christopher Mark

The first International Conference on Ground Control in Mining opened with the topic of pillar design. Two classic papers were presented, one by Bieniwski and the other by Wilson. Unfortunately, the two methods were so radically different from each other that it was nearly impossible to reconcile them. Adding to the confusion were the many other pillar strength formulas (such as the Salamon-Munro, the Holland-Gaddy, and the Obert-Duvall, just to name a few) that were also available. Little wonder that discussions of pillar design in those days often ended with anguished cries of “but which formula is the right one?” The past 25 years have seen substantial progress in the science of coal pillar design. Indeed, one testament to the improvement is the relative scarcity of papers on the topic at recent Conferences. Two factors have been largely responsible for the progress that has been made. The first has been the collection of large data bases of actual case histories of pillar performance in a variety of settings, from shallow room-and-pillar mines through deep cover longwalls. These have made possible the development of empirical design procedures that are closely linked to real world experience. The second important factor is the development of sophisticated computer models that can accurately simulate pillar behavior and roof/pillar/floor interactions. Together, these two lines of research have led to a new understanding of pillar mechanics that identifies three modes of pillar failure: • Sudden, massive collapse, accompanied by airblast, for slender pillars (width/height<4) • Squeezing, or slow, non-violent failure, for most room and pillar applications (4<w/h<10) • Entry failure or bumps for deep cover and longwall applications (w/h>10) It is particularly satisfying that the insights gained from numerical models broadly support those obtained from the empirical studies. While far less controversial than in the past, pillar design problems continue to arise. One recent example is pillar design for highwall mining. NIOSH has just released a software package, called ARMPS-HWM, which employs a number of modern pillar design concepts. Since highwall mining web pillars are long and slender, the greatest danger is that of a sudden collapse. ARMPS-HWM suggests two possible prevention strategies, one which

By William N. Patterson

Drive systems for mining machines are usually sized to accommodate anticipated peak loads. Usually, the average power requirements are considerably less. Energy storage and power averaging are attractive concepts for mining machinery and could have far-reaching implications. The purpose of this program was to: ? Identify truly feasible concepts, ? Identify advantages/disadvantages, limitations, and constraints, ? Evaluate feasibility based on today?s technology, ? Identify anticipated safety problems, and ? Provide the designer with a comprehensive literature base. Concepts evaluated include flywheels, high energy batteries, gas charged accumulators, inductive storage, capacitive storage, springs and counterweights, thermal, closed cycles, internal combustion engines, trolley systems, and hybrid systems. A comprehensive reference index is provided. Included is an appendix containing abstracts of the pertinent literature.

Jan 1, 1980

By Z. Zborovszky

The feasibility of using the nucleation properties of combustion generated particulates for the identification of their sources was investigated, using the Cloud Condensation Nuclei (CCN) Spectrometer. The Investigated materials included coal, wood, belt materials, electrical insulation, brattice cloth, and diesel exhaust. The materials were heated In an oven using filtered air flow, and their time, temperature, and the critical supersaturation spectrum of condensation nuclei (also referred to as the CCN spectrum) produced by the combusting material were recorded. Some data was obtained on a typical metal-mine background containing blasting products. The data was processed and analyzed In an attempt to specify parameters and limits that would allow the identification of the combustion sources. It appears that under controlled test conditions It Is possible to Identify the source on the basis of data derived from the CCN spectrum. More general use of the Idea for fire detection under uncontrolled practical circumstances in an actual mining environment does have potential but would require further research.

Jan 1, 1978

By Richard A. Rivell

This document is a users manual intended as a reference for personnel interested in the analysis of coal-mine-electrical-power systems under either normal operating conditions or fault situations. The interactive procedures developed for this purpose are described and implementation considerations are discussed with respect to the mine-power system. Considerations for choosing a solution technique and a number of examples are included. Procedures available include Gauss-Seidel and Newton-Raphson iterative techniques for the analysis of normal operation or balanced faults as well as a non-iterative Z-bus technique for analysis of unbalanced or balanced faults.

Jan 1, 1980

By W. M. Myers

Jet is a substance of organic origin and has been defined by the U. S. Geological Survey as a "dense black lignite, taking a good polish, and sometimes used for jewelry". Jet is characterized by the lustrous, intense black surface it displays when polished. It is due to this property that the expression "jet black" is so commonly used to imply intense blackness.

Jan 1, 1923

By M. J. Kovalik

Lower Sunnyside seam coal from Utah was blended with various proportions of char and high-temperature coke to improve the quality of the coke obtained from carbonizing this coal. The Hanson 5-pound carbonizer was used as a "screening test" for the larger scale Bureau of Mines-American Gas Association (BM-AGA) tests, which were correlated with industrial production. Eighteen carbonization tests were made in the BM-AGA 13-inch retort, with a coal charge of about 90 pounds; the cokes were evaluated by the standard ASTM tumbler test. Carbonization of blends containing char and coke breeze yielded less fissured and blockier cokes of significantly higher ASTM I-inch tumbler indices as compared with the value for the straight Sunnyside coal. It was found that the simultaneous addition of char and coke breeze yielded stronger cokes than that obtained by the addition of either one of these additives. Addition of a small proportion of Pocahontas No. 3 or Sewell coal to an optimum blend improved the resulting coke strength further.

Jan 1, 1969

By C. A. Komar

Laboratory-scale hydraulic fracture tests were conducted by the Bureau of Mines on directionally oriented sandstone material, along with measurements of directional rock properties such as tensile strength, permeability, ultrasonic velocity, and dynamic elastic constants. In these tests, fracture orientation was determined as a function of various combinations of stress, rock saturation, rate of borehole pressurization, and direction of minimum tensile strength relative to minimum horizontal compressive stress. The objective of the experiment was to investigate whether horizontal stresses always controlled the orientation of induced vertical hydraulic fractures, or if under conditions of small differences in stress and/or slow borehole pressurization rates, the induced fracture direction was influenced by directional properties of the rock matrix. This study shows that the expected influence of horizontal earth stress on the orientation of an induced hydraulic fracture becomes negligible when¬ever the magnitude of the difference between the compressive stresses is 200 psi or less. When this occurs, fracture orientation is controlled by the directional properties of the rock--primarily permeability and tensile strength.

Jan 1, 1973

The Technical Study Panel on the Utilization of Belt Air and the Composition and Fire Retardant Properties of Belt Materials in Underground Coal Mining (hereafter referred to as the Panel or the TSP) was established by Section 11 of the Mine Improvement and New Emergency Response Act of 2006 (MINER Act). The Panel was charged with providing “independent scientific and engineering review and recommendations with respect to the utilization of belt air and the composition and fire retardant properties of belt materials in underground coal mining.” The TSP was impaneled by the Honorable Elaine L. Chao and commenced its work on January 9, 2007. At this first meeting, Mr. Richard E. Stickler, Assistant Secretary of Labor for Mine Safety and Health, asked the Panel to report on many issues including how recent technological advances could be applied to atmospheric monitoring systems, point-type heat sensors, current state of fire-resistant vs. fireproof belt materials, and belt fire suppression systems to improve miner safety. In addition, Mr. Stickler asked the Panel to review belt air velocity limitations. The Panel members attended 12 days of public meetings over a nine-month period. Three of the public meetings were scheduled for the Panel to hear from technical experts and those persons or organizations interested in providing input. The meetings were held in Coraopolis, Pennsylvania with emphasis on belt fires, belt maintenance, belt flammability and toxicity, ventilation, and escape issues; in Salt Lake City with emphasis on ground control and convergence issues; and in Birmingham with emphasis on fire detection, sensors and atmospheric monitoring systems. National Institute for Occupational Safety and Health (NIOSH) researchers, Mine Safety and Health Administration (MSHA) personnel, representatives of the major belt conveyor manufacturers and a representative of the National Mining Association provided discussions at the Coraopolis meeting. In Salt Lake City, Utah, MSHA district managers and ventilation specialists, a member of the Aracoma Mine No. 1 investigation team, a representative of the Bureau of Land Management, and industry and consulting representatives of the Utah Mining Association and the Colorado Mining Association made presentations. In Birmingham, Alabama, atmospheric monitoring system representatives, NIOSH researchers, representatives of coal mining companies, and UMWA workers from two Alabama mining companies made presentations. In addition, a staff member of The Center for Regulatory Effectiveness also presented comments to the Panel. In conjunction with the meetings in Salt Lake City and Birmingham, three-member subcommittees of the Technical Study Panel made field visits to the Skyline Mine, the Aberdeen Mine, and the Jim Walter Resources Mine No. 4. The mine visits were scheduled to see first-hand the mining conditions under which belt air was being utilized as an additional source of intake air for working sections.

By P. W. Jeran, M. C. Irani, Maurice Deul

This Bureau of Mines survey of methane emissions indicates that total daily emissions have declined from 227 MM ft3 in 1971 to 214.7 MM ft3 in 1973. The highest average daily emissions in million cubic feet per day observed in U.S. bituminous coal mines were, in decreasing order, Monongalia County, W. Va. , 40.7 ; Marion County, W. Va. , 23.1 ; Buchanan County, Va. , 22.1; Washington County, Pa., 12.4; Greene County, Pa., 11.7; McDowell County, W. Va. , 11.4; Cambria County, Pa., 9.8; Jefferson County, Ala. , 9.5; Wyoming County, W. Va., 6.0; Marshall County, W. Va., 4.8; and Indiana County, Pa., 4.8.

Jan 1, 1973

By K. Hanna

This U.S. Bureau of Mines report describes a rock mechanics instrumentation program conducted in a shallow underground coal mine in central Illinois. This research program was designed to provide a basic understanding of the structural behavior of entry intersections. A wide variety of instruments and measurement techniques including hydraulic borehole pressure cells, multiple-point borehole extensometers, roof bolt compression pads, and overcoring were employed to monitor roof stresses, pillar loading, strata movement, floor heave, and bolt loading before, during, and after intersection development. A summary of intersection design theories, failure modes, and support techniques is included and instrumentation installation procedures and analysis methods are presented. The study identified two critical parameters that affect intersection stability: in situ horizontal stresses and geological discontinuities. Important design parameters for improving intersection stability are roof span and intersection geometry.

Jan 1, 1991