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By J. F. McIlwain

The Bureau of Mines has investigated fumes generated by selected welding electrodes used in mines in order to help determine their relative health hazard potential. Fumes were generated and collected in an enclosed chamber for subsequent generation rate and chemical constituent determination. Shielded metal arc electrodes from the following groups were tested: AWS types E308-16 and E310-16 stainless steel, ECoCr-A Co-Cr hardfacing alloy, ENiCr Ni, an Mn-Cr buildup alloy, E7018 carbon steel, and EII018-M low-alloy steel. Flux-cored wire electrodes of this last group also were tested. Fume generation rates and the chemical composition of the fumes were measured. From these data, exposure in-dices were determined, which give a relative measure of the health hazard potential of using the electrodes. The effect of welding onto build-up alloy layers on the fume composition also was examined for five of the higher alloy groups.

Jan 1, 1987

Reduce the costs associated with conventional treatment of acid mine water. Approach Conventional treatment of acid mine drainage consists of plants requiring large mixing and aeration tanks, mechanical aerators and large, shallow settling ponds. Such plants are usually very costly to construct, maintain and operate. The Bureau of Mines has developed a simple, low-maintenance, highly efficient system to treat acid mine drainage which mixes, aerates, and neutralizes mine water Simultaneously in the existing discharge pipeline by using the pressure generated by the deep mine discharge pumps. The mixing and aeration action of the in-line system significantly increases oxidation rates of ferrous iron. Iron and manganese are removed, even at near neutral pH levels, due to the high efficiency of this system. How It Works The In-line Aeration and Treatment System (ILS) consists of two commercially available components, a jet pump (ejector) and a static mixer. The jet pump is simply a nozzle that converts water, already under pressure, into a high-velocity stream that entrains air by Venturi action. If neutralization is required, sodium hydroxide or lime is added along with the air at the Venturi opening. The aerated and neutralized water then enters the static mixer, which is a length of internally spiralled pipe that mixes air and water together. The two components, which are both about 8 feet in length, replace the last section of discharge pipe at a point before the mine water is emptied into a pond. Along with the settling pond, these components treat the water so that it meets discharge criteria. The system has been used at surface drainage treatment facilities as well, but in such use a pump is required to provide the necessary pressure drop across the Venturi opening.

Jan 1, 1985

By M. A. Lucas

The Bureau of Mines has developed a computerized mathematical model to predict the distribution of accessory elements throughout a metallurgical process. The model can be used to determine process conditions that effect better accessory element control consistent with continued high primary metal recovery. The model presented is specific for determining the bismuth distribution in lead smelting but can be adapted to most extractive metallurgical processes. Thermodynamic, kinetic, and process parameters form the base for the model. Its logic and structure are described in detail.

Jan 1, 1983

By E. O. Binyon

The Blue Metal corundum-andalusite deposit, in the Buckskin Mining district, Douglas County, Nev., was explored by the Bureau of Mines in 1945. The results of that work were presented in Report of Investigations 3895, exploration of the Blue Metal Corundum Property, Douglas County, Nev. published in August 1946. That report also describes the property in detail, giving location, ownership, history, geology, and data on beneficiation tests. Further exploration was carried on in April and Way 1947, the results of which are presented in this report. The work consisted of 175 feet of drift and crosscut, bringing the total to 398 feet of underground working, as shown in figures 1 and 2. The 23-foot drift, which was the last work of the initial project, was extended 99 feet northward along the shear zone, and three crosscuts, spaced at approximately equal intervals along the drift, were driven to country rock on the hanging and foot walls of the zone.

Jan 1, 1948

This study was conducted to determine the feasibility of using large tractor dozers in land reclamation of strip-mined areas. The procedures used are patterned after engineering models developed for evaluation of military ground vehicles in cross-country operations. Tractor dozer manufacturers furnished information on capabilities of existing equipment and ideas on the practicability of using dozers larger than those currently available Generally, they believe that current dozers in the 500? to 700-horsepower range are about as large as can be built and remain economically feasible. However, one manufacturer has a wheeled dozer rated at 1200 horsepower, and another is testing a tracked dozer of about the same horse-power.

Jan 1, 1975

Develop a user-friendly computer program that permits those interested in mine health and safety to access and analyze on a personal computer (PC) employment, production, and accident data for U.S. coal and metal-nonmetal mines. This software is being designed with a major focus on flexibility and case of use. The Mine Accident Decision Support System (MADSS) will be available for distribution in mid-1994. Currently, the U.S. Bureau of Mines (USBM) is seeking volunteers willing to pilot test a preliminary version of the software and to provide suggestions for its improvement. Background Since 1975, the Mine Safety and Health Administration (MSHA) has compiled large data bases of information about U.S. mines and the reportable accidents, injuries, and illnesses that have occurred in those mines. Employment and production data arc collected on a quarterly basis from each mine and accident information is collected on an incident -by-incident basis. The USBM has compiled estimated costs for each of these accidents using computer models. All of this information is potentially useful to mine health and safety researchers. However, it has been underutilized because it is stored in large mainframe data bases that arc inaccessible to many users and/or are cumbersome and difficult to use.

Jan 1, 1993

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. By agreement with the American Petroleum Institute, identification of the items Is confidential. 1t presents analytical data for 4, 802 samples, representing the products of 117 companies. The samples were collected during December 1954 and January and February 1955. As in previous surveys, the gasolines covered 6y this survey Include those from both large and small suppliers. The data were obtained by laboratories of various refiners, motor manufacturers, and chemical companies and submitted to the Bureau of Mines for compilation, A list of the National Motor-Gasoline Survey reports published during the past 10 years is given on page 5.

Jan 1, 1955

By Kevin Hennings

Screening efficiency models developed to date rely almost exclusively on empirical formulas based upon large amounts of acquired operating data. A screening model was developed using a combination of empirical coefficients and explicit mathematical expressions which quantify screening phenomena. A series of screening tests was run to supply data for purposes of correlation and empirical coefficient evaluation. The model has been implemented as a digital computer program. The validity of the modeling procedure has been established by laboratory testing. Results generated by the model have been used to compile an applications handbook, which can be used to predict screening performance in lieu of using the computer program.

Jan 1, 1982

By Ronald P. Hollenbeck

Shales in the Appalachian Region of Kentucky and Tennessee were sampled and tested to determine their use as raw materials for the manufacture of lightweight aggregate by the rotary-kiln method. Nine samples were obtained from eastern Kentucky and 143 samples were obtained from eastern Tennessee. As a result of preliminary testing of these samples, two sources in eastern Kentucky and 11 sources in eastern Tennessee were resampled for rotary-kiln tests. The rotary-kiln tests showed the two sources in Kentucky and seven sources in Tennessee contained shale that would produce satisfactory aggregate. Lightweight aggregate processed from these nine sources was tested in concrete shapes and was found to be suitable for use in structural concrete.

Jan 1, 1968

By George H. Johnson

This report describes the procedures and summarizes the results of an investigation of surface subsidence above caving blocks at the San Manuel mine, San Manuel, Ariz., in order to obtain quantitative information on subsidence and ground movement caused by mining large volumes of ore. This investigation is one part of an overall study of rock mechanics being undertaken by the Bureau of Mines. Attention was given to the improvement of a rapid and precise method of surveying a large number of subsidence pins and cracks in the surface terrain. Photogrammetric methods were used as an adjunct to the triangulation subsidence surveying as well as in ordinary topographic work Maps of various kinds were prepared to show the results obtained. The computation of the survey notes was programed for an electronic digital computer at a saving of time and expense over the use of a desk calculator and trigonometric tables.

Jan 1, 1963

By Will H. Coghill, F. D. DeVaney

"Many of the iron ore deposits on the western end of the Mesabi Range Minnesota consist of the so-called ''wash ores."" Because of their high silica content these ores must be washed or concentrated to make them merchantable. Washing plants have been in operation for 20 years, during this period large quantities of tailings have accumulated in tailings ponds. These tailings contain the aggregate millions of tons of iron oxides which, if recovered, would greatly to the available tonnages and to the revenues of the mining companies. It the purpose of this paper to outline give results of concentration tests on tailings.In order that the reader may understand more clearly the type of material under consideration, a short description of the characteristics of the wash ores of the Western Mesabi Range and a brief resume a washing methods that have been are now being employed will be given. Appleby and Newton4 In their description of the district and of the ores say:The Western Mesabi district embraces the territory west of the town of Nashwauk in Itasca County. The territory to the east of this dividing line is known as the Central and Eastern Mesabi district. This subdivision is rot wholly arbitrary. While the ore bodies in the two districts resemble each other in. shape, size, and general structure, there is a marked and very important difference in the character of the respective ores. For purposes of comparison, the western deposits have been called washable ore bodies, and the central and eastern, standard ore bodies. The latter ores are the result of natural concentration processes which have teen carried far enough to produce a large proportion of high-grade ore Wet can be marketed direct; the Western Mesabi ores present a lesser degree of natural concentration and are as a rule of too low grade to admit of marketing without preliminary treatment. In many cases the grade can be improved by washing, hence the material is called washable ore. Exceptions to thin general rule may be noted in both districts. Many of the Western Mesabi ore bodies contain quite a proportion of merchantable ore. There are also portions of central and eastern Mesabi ore deposits which are of low grade and which can be improved by washing."

Nov 1, 1930

By J. W. Thompson

ORE CONCENTRATION PROCESS-PATENT OIL FLOTATION PROCESS. The invention of the patent issued to Sullman, Picard & Ballot November 6, 1906 (United States Letters Patent No. 835120), is based upon the discovery of an wholly unexplained phenomenon arising from the agitation of ore pulp containing oil and air in certain proportions. This was a discovery in an art in which it was well known that the elements of oil, air, and agitation possessed certain characteristics and produced certain results. As early as 1860 a British patent first suggested the use of oil in water concentration of ores by pointing out the affinity which oils have for metallic sub- stances in preference to gangue. Subsequently many patentees employed the known affinity of oil for metal in ore concentration proc- esses by using oil in proportions varying from 2 per cent to 300 per cent of the ore and recovering the oil-coated metal particles by causing them to rise to the top or sink to the bottom of the pulp. In these processes the agitation was either gentle or thorough but never great, and though always employed to produce thorough oiling of the metal it was used in different degrees for the sole pur- pose of causing the metal particles to rise or sink. In the prior art the oil was used for its known selective affinity for metal, agitation was em- ployed to mix the oil with the metal, and air was introduced to supple- ment the buoyancy of oil in raising oil-coated metal particles to the surface. To this extent had the art of oil flotation advanced when the patentee entered it, having reached the commercial stage in only two processes, representing respectively metal-flotation and metal-sinking processes, and having reached the stage of success in none. In the line of experiments by the patentee when the proportion of oil to ore was reduced to 1.5 per cent a "float" appeared; at 1.04 per cent still more "float" appeared; at 0.32 per cent the "float" again vastly in- creased; at 0.1 per cent the "float" again vastly increased. It thus developed that in using oil at 0.1 per cent or even at 0.05 per cent of the ore and after violently agitating the pulp from 24 to 10 minutes, there arose to the surface when the pulp was brought to rest, a thick froth or foam of oil-coated air bubbles carrying oil-coated metal particles to the extent of about 90 per cent of the metal con- tent, the foam being sufficiently stable to permit removal and metal recoveries. This was a new result based upon phenomenon then unknown and still unexplained and constituted discovery and promised a change in the art of oil flotation from laboratory experi- ments and mill failures to commercial success. The patent referred to covering the points mentioned has been sustained by the District and the Circuit Courts of Appeals and by the Supreme Court. Miami Copper Co. v. Mineral Separation, 244 Federal, 752, pp. 754-757. ORE CONCENTRATION PROCESS-OIL FLOTATION-INFRINGEMENT. The Miami Copper Co. in its process of concentrating ores by the oil flotation process used three distinct processes that were either the processes included and covered by the Sullman, Picard & Ballot patent or their fair equivalent and which were clearly an infringe- ment of the patent, and the company can not escape liability for such infringement by taking an additional step, although such additional step if taken alone would not constitute an infringement of the Sullman, Picard & Ballot patent. Miami Copper Co. v. Mineral Separation, 244 Federal, 752, p. 768. ORE CONCENTRATION PROCESS-VALIDITY OF GREENWAY PATENT. The patent issued to H. Greenway, June 9, 1914 (Letters Patent No. 1999699), is valid. The process disclosed in this patent was a substantial departure from processes of the prior art. The heating of water is a matter of large moment and the use of acids is a matter of constant and considerable expense. By wholly dispensing with both by the use of a minute quantity of hydroxy compounds, the patentee has disclosed an original and novel plan which has broad- ened and made more simple the agitation process of air flotation. The novelty and inventive character of Greenway's discovery is patentable.

Jan 1, 1918

By Paul C. McWilliams

The U.S. Bureau of Mines has, primarily through its contract program, used large-scale centrifuges to determine design criteria for tailing embankments. The centrifuge runs were made at two installations, the University of Cambridge, Cambridge, England and Sandia National Laboratories, Albuquerque, NM. The major problems considered were as follows: slope stability of embankments, modeling erosion and seepage, use of the phreatic surface level to ascertain the validity of centrifuge modeling, and the effects of compaction and weathering on a tailings embankment. This report summarizes the results of the four test series conducted at University of Cambridge and Sandia National Laboratories. A review of prior centrifuge applications to mining problems is included. Consideration is given to future centrifuge application to mining problems in both soil and rock mechanics.

Jan 1, 1989

By M. P. Ristenbatt

A new automated post-disaster signaling system, intended to use through-the-earth EM propagation, was demonstrated in the laboratory at an input SNR of -34 dB. The system presently available requires an input SNR of +6 dB, and uses a human-ear detector. The work here demonstrated coherent integration, for the automated system, in multiples of 17 s, up to 1088 s (18 minutes). A repeating pseudorandom (or pseudonoise) signal is used, which offers an ideal auto-correlation at the receiver matched-filter output. A novel decision-variable algorithm achieves the estimate of noise level by using those matched-filter output samples that occur between the signal auto-correlation peaks. This work included corraboration that the received signal power decreases as distance to the tenth power, for through-the-earth propagation. Thus, the above 40 dB reduction in required input SNR permits an automated system to have a range 2.5 times that of the present system. In addition, an automated system permits the possibility of operating receivers around-the-clock; this would reduce the initial-detection-time from a few hours (present system deployment time) to a few minutes (signal processing time).

Jan 1, 1981

Coaxial cable structures form the subject of substantial theoretical and experimental investigations either directly related, or which can be extrapolated, to the communications needs and environments of U.S. coal mines. Communication systems based on "guided" waves, of which "leaky" coaxial cables are one implementation, are attractive candidates for providing a range of communication functions primarily along haulage ways, and possible also within sections up to the working face. (However, there are still strong reservations as to whether a practical coaxial cable sys tem could provide sufficient communications coverage within a section. ) In this Part, we present the results of some theoretical calculations of the performance of leaky coaxial cable communication systems. We also analyze the applicability of the theoretical and experimental results obtained by other researchers to the needs of U.S. coal mines. In particular, this investigation has been focused on the utility of relatively low cost, conventional, flexible, coaxial cable at frequencies covering the LF through HF bands and extending into the lower part of the VHF band, as opposed to relatively high cost, special semi-rigid, coaxial cable* at frequencies in the VHF and UHF bands. There are three major design alternatives for coaxial cable communication systems considered in this chapter: • Base station feeding a coaxial cable with high surface transfer impedance (holes in outer conductor, e.g., braid construction). • Base station feeding a coaxial cable with repeaters (U.K. experiments). • No base station, direct communication via a coaxial cable with periodic radiative structures.

Jan 1, 1974

By D. S. Burgess

About 100 tests of flammability were carried out with H2, CH4, and CO in mixtures with air using the Federal Bureau of Mines 12-ft-diameter spherical pressure vessel as an explosion test chamber. The LeChatelier approximation gave slightly conservative estimates of the limits of downward flame propagation (onset of significant pressure rise) using the following measured values for the individual gases, in percent: H2, 8.5; CH4, 5.25; CO, 13.0. No justification could be offered for using the LeChatelier law for upward flame propagation limits and indeed reported data suggest that calculated values would not be conservative. The observed upward limit for methane-air mixtures (4.85 pct) was less than the widely accepted lean limit for this fuel; those for lean hydrogen-air mixtures and carbon monoxide-air mixtures did not differ from the lowest accepted values. Diffusional effects on the propagation of single, binary, and ternary fuel mixtures are discussed.

Jan 1, 1982

By Laurence G. Trudell

A geologic framework for interpreting stratigraphic and geographic variations of the Green River Formation in the Piceance Creek Basin is developed from lithologic data accumulated by the Bureau of Mines from oil-shale coreholes. From detailed Bureau of Mines descriptions of samples from nine coreholes and supplementary lithologic data from seven additional sampled sections, three cross sections were constructed along lines transecting the basin. Plotted as lithologic columns with corresponding oil yields and resistivity logs, the sampled sections are correlated on a time-stratigraphic basis. Distribution and correlation of nahcolite and halite zones are shown, and the approximate base of leaching of these saline minerals is indicated. General lithologic characteristics of members and zones are discussed and interpreted. Large-scale lithologic logs illustrate the nine Bureau of Mines core descriptions, and the complete description of Bureau of Mines-Atomic Energy Commission Colorado Corehole No. 1 is included in an appendix. The time-correlated cross sections provide a necessary framework for understanding the depositional history of the Green River Formation and will facilitate evaluation of oil shale and other mineral resources in the Piceance Creek Basin.

Jan 1, 1970

By N. A. Pace

This is one of a series of papers being published by the Federal Bureau of Mines for the dissemination of information on methods and practices used in the mining and preparation of crushed stone for market requirements. Performance in terms of units of work or tons produced per machine and per operator man-hour are given whenever that information is available. Direct operating costs are useful for comparing different methods, and are, therefore, included if possible. In addition to the factual description of equipment and methods used, it is desirable to discuss the engineering reasons for the choices that have been made. This paper is particularly concerned with the opertions at the Columbia plant of Palmetto Quarries Co. of Columbia, S.C. The plant is about one-half mile east of the Congaree River and adjacent to the southwest corner of the city of Columbia. Rail access is by the Atlantic Coast Line Railroad, and by a spur strack of the Seaboard Airline Railroad.

Jan 1, 1962

By Michael G. Zabetakis

Vaporization of a solvent into an airstream at temperatures above the flash point of the solvent is hazardous if vapor is liberated at a rate that is sufficient to produce a flammable mixture. In may operations, the formation of such a mixture is prevented by rapid diluton of the vapors with air. The minimum air requirements for the dilution process are determined by the composition of the lower limit mixture at the temperature and pressure of interest. Because limits of flammability cannot always be calculated with sufficient accuracy for a proposed operation, they .rust often be determined experimentally. The present Bureau of Mines investigation was prompted by an application in which the lower limits of flammability of a number of solvent mixtures were required over a range of temperatures at atmospheric pressure. These limits were to be used along with available solvent-vaporization-rate data to establish minimum airflow rates needed to prevent the formation of flammable mixtures in an industrial process. Lower limits of flammability were determined for a number of mixtures containing methyl ethyl ketone, tetrahydrofuran, toluene, ethyl alcohol, and ethyl acetate in dry air-at atmospheric pressure and temperatures between 16° and 200° C. The experimental values were found to be in good agreement at with those predicted by Le Chatelier's law; variations with temperature were in fair agreement with those predicted by a modified Burgess-Wheeler law.

Jan 1, 1962

Quickly and cheaply consolidate underground slimes to facilitate their use as backfill and permit their easy handling for other reasons. Approach: The slurry containing slimes is pumped into active stopes and electrokinetically dewatered to provide consolidated back fill. How It Works: To densify slimes electro-kinetically two electrodes are placed in the material to be dewatered and densified. Typically, the electrodes are pieces of wire mesh fencing. One is placed on the bottom, and the other is suspended in the slurry near the surface. Figure 1 is a simplified section of a test. A d-c voltage of 100 to 400 volts is applied across the slurry. This causes the solid particles which are in suspension in the water (usually these are negatively charged) to migrate toward the anode; simultaneously, the water moves toward the cathode. Water immediately adjacent to the negatively charged solid particle surfaces contains an excess of dissolved positive ions. When these ions are attracted to the electrode and move towards it, they also exert

Jan 1, 1976