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By R. E. Perry

To develop new or improved flotation methods for beneficiating low-grade red iron ores, the Bureau made many bench scale and continuous anionic flotation tests on ferruginous sandstones and calcareous iron ores from the north-eastern part of the Birmingham, Ala., iron district. The ores contained about 21 to 36 percent iron, a to 11 percent lime, and 22 to 64 percent silica. Production of iron concentrates containing 48 to 52 percent iron was technically feasible in batch tests, and the iron recoveries ranged from 85 to 92 percent. In continuous tests 49 to 51 percent iron products were obtained with 80 to 90 percent recovery.

Jan 1, 1962

By Ronald H. Church

The Bureau of Mines tested & ground penetrating radar (GPR) system in the central Florida phosphate district. to determine the feasibility of utilizing GPR technology for subsurface cavity detection. The test area is located in karst topography where sinkhole development is prevalent. State regulations require subsurface drilling of damsites to identify underground anomalies; however, this method is not totally accurate in locating subsurface cavities that could lead to sinkhole development. An electromagnetic method of identifying anoma-lous subsurface conditions could reduce or eliminate the possibility of dam failure due to sinkhole development. The Bureau devised a GPR system that successfully penetrated over 50 ft of overburden and gave recognizable radar return signals characteristic of a rock-cavity interface.

Jan 1, 1986

By F. J. Cservenyak

The Bureau of Mines Solid Waste Program is directed toward three main areas of research: (1) Extraction of mineral, metal, and energy values from urban refuse; (2) recovery of mineral and metal values from wastes generated in the industrial extraction, processing, and utilization of raw materials and mineral-base products; and (3) upgrading and utilization of automotive scrap. The Bureau also has a contract and grant program which supplements the in-house research and aids in the training of personnel in the proper management of mineral- and metal-based solid wastes.

Jan 1, 1970

By Staff

This U.S. Bureau of Mines publication presents the results of investigations into the fire and explosion hazards of oil shale rocks and dust. Three areas have been examined: the explosibility and ignitability of oil shale dust clouds, the fire hazards of oil shale dust layers on hot surfaces, and the ignitability and extinguishment of oil shale rubble piles.

Jan 1, 1989

By P. D. Kovscek

The performance of a novel prototype kerf-cutting impact mining machine was evaluated under a cooperative agreement between the U.S. Bureau of Mines and RAMEX Systems, Bellevue, WA, while operating under conditions typical of normal tunnel entry development. Selected operating parameters were monitored concurrently to determine baseline operating conditions and to study relationships between operating parameters. Using the data obtained, the specific energy requirements of the impact mining machine were calculated and compared to specific energy requirements of tunnel boring machines cutting in rock having similar hardness. Tests results indicate that the kerf-cutting impact mining machine can provide a mechanical means for mining very hard rock that cannot be effectively mined using commercially available mechanical excavators.

Jan 1, 2010

By J. J. Forbes

Ventilation is the most important safety factor in the production of coal because on it depends the safety, health, and efficiency of those who work underground. Without adequate and efficient means of supplying fresh air to the working faces, mining could not have advanced as it has. The extent of the workings, the increase in mechanization, and the increasing use of electricity are largely responsible for changes in methods of ventialtion. Ventilation in the early, days of coal mining was accomplished by means of a natural draft, created principally by a difference in the weights of columns of air between the intake and return openings: Later the furnace was introduced for the purpose of increasing the quantity of air in circulation. Mines continued to become larger, their output increased, men were employed in greater numbers, and more fresh coal surfaces were exposed. Coal beds near the surface, and practically free from explosive gas became exhausted, and deeper beds that liberated methane were opened as development advanced. Mechanical ventilation became necessary and was first accomplished by disc-type steam driven fans she old-.fashioned steam driven disc fan has generally been supplanted by the powerful electrically operated centrifugal fans in use at modern coal mines. In order to be secure against gas explosions and provide ample fresh air for persons employed in large coal mines, air must be conducted through the mine to all working places and to all other unsealed parts of the mince in sufficient quantities to dilute and render harmless all dangerous and noxious gases.

Jan 1, 1929

By Ann G. Kim

Hydrocarbon gases, primarily methane but also the C2 through C5 paraffins, the C2 and C3 olefins and possibly the C4 and C5 olefins, are byproducts of coal formation. Although it is generally believed that coal formation occurred at temperatures below 200° C, most experimental work on gas formation from coal has been performed at temperatures between 200° and 1,000°C. The objective of this Bureau of Mines experiment was to determine if observable changes in the gases from coal could be produced at temperatures below 200° C in relatively short periods of time. The experiment involved heating coal samples from six coalbeds at constant temperatures and analyzing evolved gases. The composition of the gases at three temperatures was compared. At 35° C, over 99 pct of the gas is methane; at 125° and 150°, methane constitutes approximately half of the hydrocarbon gas. Isobutane and pentane are the predominant higher hydrocarbons at temperatures between 100° and 150° C.

Jan 1, 1974

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations No. 4251. The factual data obtained during the project are reported in a series of Reports of Investigation beginning with No. 4251, of which this is the sixth. The data are accompanied by maps showing the loca.ion of holes, drilled and the deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township map. The description of each half township is followed by a description of each deposit developed in that half township. The 14 half-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled on the project except the deep holes drilled to test geophysical anomalies. The locations of those holes are shown on figure 13 in Volume I. The descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each half township is given with the discussion covering that area.

Jan 1, 1948

By J. E. Berg

This paper3 describing the mining methods at the Page mine operated by the Federal Mining & Smelting Co., is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The Page mine is the most westerly of the producing lead-silver-zinc mines in the Coeur d'Alene mining district of Idaho, being situated 5 miles west of the city of Kellogg and at an elevation of 2,677 feet above sea level. It may be classed as one of the new active producers, of the district and owes its present activity largely to the development of floatation.

Jan 1, 1930

By H. W. St. Clair

This study of the rate of evaporation of zinc was undertaken as a part, of a general investigation on refining mixtures of metals resulting from melting reclaimed scrap. One of the methods by which the more volatile metals, such as zinc, magnesium, and cadmium, may be separated is by distillation. Distillation may be carried out at lower temperatures if it is done in an evacuated enclosure. The immediate purpose of the present investigation was to determine accurately the effect of temperature, pressure, and other factors on the rate of evaporation of zinc.

Jan 1, 1950

The overall objective of this study is to gather operational data from selected surface coal mining systems in the United States, and to assess the potential production and economic capacity of the systems. The study includes: four mines, each using a different mining technique and different equipment. One mine was selected from each of the major coal fields: Midwestern, eastern,, northwestern, and southwestern. The Midwestern Mine is located in the Central Plains and produced 1.45 million tons of raw coal during the study year The Midwestern Mine uses the area mining or box-cut technique. A large in-pit shovel and a bucket wheel excavator are used to remove the overburden. Coal is removed by a loading shovel and transported to the dumping point by large off--highway trucks.

Jan 1, 1975

By Stephen P. Holt

During the spring and summer of 1946, the Bureau of Mines put down 8 churn-drill holes and 9 diamond-drill holes, totaling 3,535 feet of bore, at the Blewett zinc-lead deposit in Jo Daviess County, Ill. Attention of the Bureau of Mines was first directed to this deposit by the Illinois State Geological Survey, which had investigated the Blewett mine. In the opinion of the Survey and the Bureau of Mines, the record of production and results of drilling previously done on the property were considered sufficient justification for continuing investigation to the north and south along a projection of the trend. This report describes the work done by the Bureau on this, property and presents the data obtained.

Jan 1, 1948

By V. A. Marple, K. L. Rubow, B. A. Olson

"INTRODUCTION Inertial classification, gravitational sedimentation centrifugation, and thermal precipitation arc techniques that can be used to collect particles for subsequent analysis or for particle classification. The inertial classifiers, which include impactors, virtual impactors, and cyclones, are widely used in the sampling or particles. Settling chambers, which include centrifuges as well as gravitational settling devices, are less widely used. Thermal precipitators arc seldom used.Impactors, in particular, have been used extensively, studied both theoretically and experimentally, and arc the instrument or choice for the determination or aerosol mass size distributions. Many versions or impactors arc available commercially and many more have been designed, built, and used in special studies.Virtual impactors are a more recently developed inertial classifier and possess a feature not round in conventional inertial impactors; namely, that the particles remain airborne after classification compared to the conventional impactor, where the particles arc collected on a solid surface. The feature or keeping particles airborne is important for transporting the particles to other particle-analyzing instruments, or to filters, and in concentrating particles larger than the cutsize in a small fraction of the total now."

Nov 1, 1995

By Emory Smith

The Victorville cement plant of the Southwestern Portland Cement Co. is located about 1 mile from the city of Victorville, Calif. Two transcontinental railway systems, the Atchison, Topeka & Santa Fe, and the Southern Pacific Railroad, afford shipped facilities. The plant is modern and well kept, as the officials, especially the higher operating officials, take pride in the appearance of the place. Dust has been practically eliminated by the installation of dust collectors and wet grinding. The plant has a rated capacity of 5,000 barrels of cement daily.

Jan 1, 1929

By John T. Dieckmann

This report documents the work performed and the results obtained in a 2-year development of a Mobile Inert Gas Generator for use in the Bureau of Mines Remote Sealing System for fighting underground coal mine fires. The performance requirements of an inert gas generating system for the Remote Sealing System were clearly established. A thorough review of seven possible system designs meeting these requirements was conducted. An air cooled, distillate oil fired combustion type inert gas generator was selected for further detailed design, hardware fabrication, and performance testing. The Inert Gas Generator constructed under this program has been thoroughly performance tested and has been operated in the field for approximately 200 hours. The system has met or exceeded all important performance requirements. The system was used in the fire fighting efforts at the Bethlehem Mines Corporation Cambria Division Mine 33 fire and contributed to the successful containment of the fire. The system was also employed in the demonstration of entire Remote Mine Sealing System at the Jenney Mine in the fall of 1978. The system is currently avail-able for fighting any future underground coal mine fires.

Jan 1, 1979

By Agnes Y. Lee

The Bureau of Mines has developed an effective hydrometallurgical method to recover high-purity Pb metal and elemental S from concentrates. This low-temperature process eliminates S gases and Pb emissions, in contrast to the current high-temperature smelting technology. The method consists of (1) oxidative leaching with H202, Pb02, and waste fluosilicic acid at 95° C to produce a solution of PbSiF6 and a residue containing elemental S, (2) electrowinning the PbSiF6 solution at 35° C to produce 99.99 pct Pb metal and H2SiF6, and (3) solvent extraction to recover S, leaving a residue containing Cu, Ag, and other metal values. Spent electrolyte was recycled repeatedly, with impurity buildup controlled by controlling the leach parameters.

Jan 1, 1986

By John C. Machisak

THE INJURY data and experience at quarries and related plants of the United States are presented in this publication under the following general sections (A) General injury experience: Tables 1-3: Current data on number of injuries, injury-frequency rates, location, accident agency, degree of injury, and related employment data. (B) Injury experience at different kinds of quarries: Tables 4-5: Current data on number of injuries, injury-frequency rates, location, accident agency, degree of injury, and related employment, data. (C) Injury experience by States: Tables 6-20: Current data on the number of injuries, injury-frequency rates, accident agency, degree of injury, and related employment data. (D) Selected injury data: Tables 21-30: Current data on various selected factors of operating conditions at different kinds of quarries, including employment size-groups, length of shifts, comparative severity of injuries, and injury data and related employment experience at dimension-stone and nondimension-stone quarries and at underground quarries. (E) Historical injury experience: Table 31: Injury and employment data on the quarrying industry for 1911 through 1957. Statistical data on injuries and related employment in the quarrying industries have been collected annually from the operating companies since 1911. Reporting to the Bureau of Mines is voluntary; there is no Federal law compelling operators of quarries and related plants to supply such data. Data presented herein may not be complete for the entire industry. They are however, believed to be representative of the hazards common to all quarry and related workers. Moreover, the figures are comparable as between States-a significant fact in view of the lack of uniformity among the States with regard to the classes of injuries covered by State reports and other factors that tend to make it impracticable or impossible when using State records to

Jan 1, 1960

By B. R. Mohal, S. Chander

"A new technique to determine wettability of powders is presented in this paper. In this technique the times for immersion of individual particles from air into liquids, defined as imbibition times, are measured. Through the measurements of imbibition times for a large number of particles, it is possible to determine homogeneity/heterogeneity of a powder sample with regard to its wetting behavior. Quartz particles give a very narrow distribution of imbibition times showing a homogeneous wetting surface whereas coal particles give a broad distribution indicative of the heterogeneous nature of its surface. The imbibition time measurement technique is considered to have certain advantages over other methods to determine wettability of powders in surfactant solutions. In this study we have also compared the imbibition times with the wetting rate mea¬surements obtained by a modified Walker test.INTRODUCTIONSeveral methods are available for determining wetting characteristics of sol¬ids. Each of the methods has been used in the past to obtain very valuable information for comparing wetting behavior of various solids in a given liquid or for comparing the wetting behavior of several liquids for a given solid. Each method measures a somewhat different aspect of wetting and therefore quantitative correlations between techniques have been difficult. A general approach is to use a method in which close similarity between the technique and the application (where results of wetting measurements are to be used) can be maintained. The objective of this investigation was to develop a method which could be used to determine the wetting characteristics of single particles in surfactant solutions. Wetting of individual particles is of importance in cap¬ture of dust particles by sprays of surfactant solutions.METHODS FOR DETERMINING WETTING — A BRIEF REVIEWThe various methods available for measuring wetting characteristics of solids include: contact angle, immersion/sink time, bubble pick-up, induction time, capillary rise, and displacement method measurements. Some of the methods are briefly reviewed in the paragraphs that follow."

Mar 1, 1989

By W. M. McKewan

This U.S. Bureau of Mines report discusses wire ropes used for hoisting in U.S. mines. The in-formation presented was extracted from a large body of data compiled by the U.S. Mine Safety and Health Administration (MSHA) using a data base management system (DMS). Further, these extracted data were then manipulated to provide tables of data that show the types and amount of wire rope used for hoisting. This report describes the different types of wire ropes and how a DMS can be used to manipulate MSHA's wire rope inventory data. The data indicate that more 1-1/4-in-diam ropes, 6x27 construction ropes, and right lang lay ropes are used in U.S. mines than ropes of any other diameter, construction, or lay type.

Jan 1, 1991

By J. S. Webb

This is one of a series of papers dealing with mining methods, practice, and costs be¬ing published by the United States Bureau of Mires. In this paper a description of the mining practice in vogue at the Braden unit of the Kennecott Copper Corporation is undertaken. PRODUCTION At present (1931) the entire production of ore is being obtained from the Teniente mine. The miring method in use is an adaptation of block undercutting which has been a development of the stoping and pillar caving experience obtained at this property. Improvements in mining practice are constantly being made.

Jan 1, 1932