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By E. R. Palowitch

This report is the result of a series of coal-cleaning tests using a dense-medium cone-type washer. Detailed results are given for 2 tests using a magnetite medium and 4 tests using a pulverized-refuse medium. Approximately 120 float-and-sink tests and over 500 separate chemical analyses were made in conjunction with these tests. In these tests higher recovery efficiencies and sharper separations were obtained when using a magnetite medium, especially on coal sizes below one-half inch. When sizes above 1 inch at low specific gravities of separation are cleaned, the pulverized refuse medium compared favorably with the magnetite medium.

Jan 1, 1956

By Anil Mahyera

Towards the goal of achieving uniform-high-tensions in roofbolts to provide superior roof support[1-7] for extended periods, Terra Tek installed mechanical-anchor bolts in a mine in eight different ways -- under torque/thrust control with and without hardened washers, belleville washers and tension equalization; in a conventional manner with and without a hardened washer. The various bolt groups were analyzed in terms of their tension uniformity and mean tension levels. Installing the bolts accurately with ? a hardened washer under the bolthead, and ? proper torque/thrust control resulted in the mast uniformly tensioned bolts -- with a coefficient of variation of only 14%, an improvement of 3 times over a conventional installation. Also, these bolts maintained a high tension level -- 80% of the installation tension, compared to 50% achieved conventionally.

Jan 1, 1982

By A. T. Harris

Ground quartzite, known in the industry as amorphous silica, is produced from a quartzite deposit near Honey Brook, Pa., by George F. Pettinos, Inc., of Bala-Cynwyd, Pa. The quartzite is mined by the open pit method and processed in a mill at the mine. The operation regularly produces five standard grades of sand and one grade of crushed stone; however, the company accepts special orders and will produce material to meet the customer's specifications. Beneficiation (chiefly crushing and screening) is controlled by laboratory screen tests on samples taken during preparation of the sand. The chief uses of the sand are for foundry operations, furnace lining, concrete aggregate, and other specialized uses. The quartzite in this deposit is of uniform composition and does not require control by chemical analysis. However, for special purposes, analysis will be furnished.

Jan 1, 1965

By John Gross

The modern practice of grinding ores so that often 80 per cent or more of the product is finer than 200 mesh makes it desirable to supplement sieve sizing so as to extend considerably the range of sizing. Moreover, the fact that the material finer than sieve size represents the major part of the work done in grinding emphasizes thick need in can investigation of crushing efficiency. A method based on the settling rate of particles in grater appeared to be most practical for sizing; finely ground ores. There are two possible methods of utilizing this principle: one based on free settling or sedimentation; and the other on separation by means of a rising; current of water, or elutriation. In sedimentation, mechanical entanglement causes material at the start to settle in a mass, and this persists throughout. As this feature is largely eliminated by elutriation, which permits a comparatively clean separation of the various sizes, the elutriation method was adopted.

Jan 1, 1929

By George S. Rice

In 1911 the Director of the United States Bureau of Mines instructed the chief mining engineer of the bureau , during an investigation of coal-mine safety conditions in Europe, to ask the directors of the various mine-experiment stations whether they would favor a European conference . The majority of the officials in immediate charge of experiment stations favored the plan , and Victor Watteyne, inspector general of Belgium, suggested that the United States call such a conference to be held immediately after the Eighth International Congress of Applied Chemistry, which was to assemble in New York on September 3, 1912 . Accordingly, invitations were issued by the United States Government to those countries having mine-experiment stations , namely, Austria-Hungary, Belgium, France, Germany , and Great Britain, and to those that contemplated the establishment of such stations , Canada and Mexico . All but Great Britain and Canada accepted ; Mexico designated a representative , who later found it impossible to come. The Government of Great Britain in declining, expressed regret at its inability to accept ; an informal statement was made that the opening of the experimental gallery at Eskmeals , England , occupied the attention of the officials in charge . Delegates were appointed by their respective Governments as follows: Austria-Hungary, Julian Czaplinski , royal mining engineer. Belgium, Victor Watteyne , inspector general of mines . France, J. Taffanel, director of the Lievin experiment station . Germany, Carl Beyling, bergassessor, director of Dortmund experiment station. United States , Charles E. Munroe, consulting explosives expert and George S. Rice, chief mining engineer of the Bureau of Mines . Subsequently Mr. William O'Connor , a mining engineer and mine operator of Wales , who opportunely appeared at the Pittsburgh station with letters of introduction from the South Wales Institute of Engineers and from prominent mining officials of Great Britain , was unanimously invited to take part in the meeting as an unofficial representative of Great Britain . Messrs . Beyling, Taffanel , and Watteyne were met in New York on September 3, by George S. Rice, who accompanied them to Washington, where they were welcomed by Director J. A. Holmes , of the Bureau of Mines , and where , with the delegates to the Eighth International Congress of Applied Chemistry , they were presented to President Taft . Mr. Taffanel was unfortunately called back to France just before the scheduled time of the conference on account of a mine disaster ; the other delegates , including Mr. Czaplinski , convened at Pittsburgh on the morning of September 14. Mr. Rice, representing the Director of the Bureau of Mines , acted as temporary chairman , and called the meeting to order.

Jan 1, 1914

By R. M. GRANTHAM, J. H. SOULE

C. R. Keyes, F. C. Schrader , F. A. Jones ( the first director of the New Mexico School of Mines , whose name was given the deposits ) , and N. H. Darton all described the Jones iron deposits within a decade after their discovery in 1902 . The earliest locations now on record were made in 1927. Interest in iron ores was revived during the second World War . Paul E. Pesonen , of the Bureau of Mines , reported on the deposits in December 1941 and proposed an extensive exploratory program . In March 1942 , the deposit was reported upon by C. H. Johnson , also of the Bureau of Mines , and a definite program of exploration was outlined .

Feb 1, 1947

By E. C. Fitch

This report discusses fire-resistant hydraulic fluid safety from three different directions. First, results of a survey prepared for the Fire Resistant Hydraulics Journal by the staff of the Fluid Power Research Center are analyzed. Second, operational limitations of fire-resistant hydraulic fluids are examined. Finally, laws and standards of various foreign countries are investigated. Three conclusions are derived from a close study of fire-resistant hydraulic fluid safety from these three directions. First, a significant number of experts in the fluid power industry are no in agreement about aspects of fire-resistant hydraulic fluid fire-resistance and toxicity. This indicates a need for more in depth research. Second, the use of fire-resistant hydraulic fluids involves a compromise between the decreased fire hazards and increased toxicity and machine incompatibility problems. Finlly, major foreign governmental agencies have thorough laws and standards concerning fire-resistant hydraulic fluids. These laws and standards may provide a solid framework for further international research into fire-resistant hydraulic fluid safety.

Jan 1, 1979

By Edmund S. Leaver

The Precious Metals Section is concerned primarily with ore-testing problems associated with precious metals and with the analysis and concentration of a large number of the strategic-mineral samples that have been included in the research program of the Bureau of Mines. During the fiscal year 1938-39, 30 projects were completed. The requests for this service are based upon the desire of the sponsor to obtain the best or most satisfactory method for maximum recovery of the minerals. In many instances it is a question of improving present milling practice, with due regard to utilization of present equipment. In others, the probable tonnage available maybe the deciding factor in the choice of a particular recovery method. Under all circumstances the results of tests axe prepared with the thought of aiding a competent metallurgist, familiar with local conditions, to formulate a practical flow sheet or to assist the mill operator to correct known losses. A microscopic examination for identification of the mineral constituents and their association in each ore is always a big help, in planning the tests and may indicate the reason for former troubles or assist with best procedure.

Jan 1, 1940

By Edmund S. Leaver

The Precious Metals Section is concerned primarily with ore-testing problems associated with precious metals and with the analysis and concentration of a large number of the strategic-mineral samples that have been included in the research program of the Bureau of Mines. During the fiscal year 1938-39, 30 projects were completed. The requests for this service are based upon the desire f the sponsor to obtain the best or most satisfactory method for maximum recovery of the minerals. In many instances it is a question of improving present milling practice, with due regard to utilization of present equipment. In others, the probable tonnage available maybe the deciding factor in the choice of a particular recovery method. Under all circumstances the results of tests axe prepared with the thought of aiding a competent metallurgist, familiar with local conditions, to formulate a practical flow sheet or to assist the mill operator to correct known losses. A microscopic examination for identification of the mineral constituents and their association in each ore is always a big help, in planning the tests and may indicate the reason for former troubles or assist with best procedure.

Jan 1, 1940

By A. R. T. Denues

"INTRODUCTION The orienting phases of the current investigation of cushioned blasting in the Explosives Division of the Bureau of Mines were indicated in a previous publication (5) 3/. Pertinent literature reviewed therein indicated a highly controversial field. This emphasized the need for experimental studies of many factors that affect the health and safety of miners and the efficiency of mining operations. Results of some orienting tests showed marked effects on practical hazards. Further, they emphasized the necessity and importance of the contemplated investigation. The scope and general plan of these practical inquiries into the safety of cushioned blasting were indicated.This investigation of cushioned blasting relates to the various means employed to reduce the intensity of application of energy from explosive actions in boreholes. It has been suggested (from p. 19 of reference that the divisions of this work would correspond to the salient hazards affected by cushioned blasting. These include the ignition hazard, hazards from poisonous gases, and other practical hazards in the blasting technique. The ignition hazard was resolved into two components of approximately equal weight. These include studies of effects upon (1) the incendivity of blown-out shots and upon (2) the occurrence of such shots. Experimental studies of effects on the incendivity of blown-out shots were first undertaken. Questions of the best procedure for making these evaluations have been adduced, and the interpre-tation and utilization of the results of gallery testing seemed to require detailed attention; some preliminary general considerations of such testing were therefore necessary."

Jan 1, 1943

By L. A. Grant

This paper describing the concentrator practice of the Montana Mines Corporation at Helena. Mont., is one of a series of articles on milling methods and costs being prepared by the United States Bureau of Mines. The Spring Hill mine and mill are located 4 miles south and west of Helena, Mont., near the head of Grizzly Gulch. The mine portal is on the east slope of the gulch, and the mill is directly opposite on the west slope. Grizzly Gulch is one of the tyro gulches which unite at the south end of Helena to form Last Chance Gulch, on which the main street of Helena is built.

Jan 1, 1931

By C. Q. Cupps

n view of increased interest in secondary recovery of oil in the Cut Bank field, Montana, a review has been made of unpublished data obtained during a 1943-44 study of reservoir oil characteristics in this field. Considerable uncertainty was attached to interpretations of subsurface oil sample analyses from six Cut Bank zone wells, one Lander sand well, and one Moulton sand well, because of adverse sampling conditions and wide range in the data. Much of this uncertainty has been removed by this review which has shown two of the Cut Bank zone samples and the Moulton sand sample to be representative of the reservoir oils. Estimates of original reservoir oil characteristics derived from differential-liberation analyses of these samples show that the oil in the Cut Bank zone was initially saturated at the gas-oil contact pres-sure, 750 psia, and the oil in the Moulton sand was undersaturated with a saturation pressure of only 380 psia. The rest of the samples were indicated to be nonrepresentative of the reservoir oils because of a disproportional vaporization of heavier components of the solution gas. The vaporization of these components is believed to be a cumulative effect of contact of the oil with bypassing, light-gravity gas which had been liberated at higher pressures from solution in oil farther back in the formation, or which had come from the gas cap, rather than from the singular effect of gas evolution caused by excessively low bottom-hole pressures. Change of oil composition caused by the latter was found to conform closely to that occurring during a differential liberation of gas in the laboratory.

Jan 1, 1967

By J. M. Kuchta

Concentrated hydrogen peroxide (H202) is a highly reactive oxidizing agent that liberates heat when it decomposes. The heat liberated may be sufficient to ignite combustibles with which the peroxide comes in contact. For this reason, concentrated hydrogen peroxide should be handled only by personnel familiar with its many unique properties.6 Hydrogen peroxide is used as a bleaching agent in the manufacture of textiles; this is its major single use in the United States. It is also employed as a reagent in chemical synthesis, as a source of free radicals to start polymerization, as a foaming agent in the manufacture of porous substances, and for its effect on biological processes. Moreover, highly concentrated hydrogen peroxide is a compact source of energy that can be utilized both as a monopropellant and as the oxidizer in a bipropellant system, During World War II, large quantities of highly concentrated hydro- gen peroxide were used as propellants, particularly in Germany. Since then, production of the peroxide has increased rapidly; in the United States alone it has more than doubled since 1950.7 Because of its widespread use, increasing interest has been shown in the hazards of handling the high- strength peroxide.

Jan 1, 1961

By Thomas J. Peters

The Danskin/South Fork Boise River study area is 40 air km southeast of Boise, Idaho. The 16,000-hectare, two-segment area is mainly underlain by Cretaceous-age granodiorite and an aplitic and pegmatitic complex of the Idaho batholith, Miocene-age rhyolitic tuffs and lavas, and late Tertiary-age basalt flows. No mineral resources were identified in the study area. One mine, The Flat Creek mine, which produced several ounces of gold and silver, was found in the study area. It is geologically similar to deposits in the Neal mining district, adjacent to the northwest corner of the area; gold mineralization occurs along east-northeast-trending faults and associated quartz veins, which dip moderately to steeply southeast, and within adjacent Cretaceous granitic rock. Samples indicate the Flat Creek deposit is not rich enough to mine underground, and near surface, open-pit-mineable deposit areas could not be identified. However, exploration is warranted there and also in the 7-km interval to mines in the Neal district, and for extensions of those mines. No evidence of geothermal activity was observed, although there are hot springs in the vicinity. Some alluvial (placer) samples from the interior of the study area contained free gold, but no substantial gravel deposits were seen.

Jan 1, 1993

By M. E. Tyrrell, C. W. Houck

Mixtures of zirconium diboride and refractory metals of group VI were resistance sintered to high - density compacts using modified electric welding equipment . To evaluate the use of chromium , molybdenum , or tungsten as binders for zirconium diboride the sintered compacts were examined in polished sections and tested for crushing strength , hardness , microhardness , oxidation rate , and resistance to mechanical shock . Chromium yielded the highest compressive strength , the greatest resistance to mechanical shock and oxidation , and a satisfactory Rockwell hardness . Molybdenum did not yield a satisfactory cermet . Tungsten yielded compacts having high microhardness but very low mechanical strength .

Jan 1, 1964

By Arthur B. Campbell

This Bureau of Mines report describes a method that utilizes a computer program to evaluate integral Gaussian profiles of atomic concentration versus depth in a solid. The specific use illustrated involves profiling ion- implanted metals using proton-induced X-ray emission (PIXE) analysis and ion sputtering (IS) for sectioning

Jan 1, 1979

By R. W. Hiteshue, C. O. Hawk, H. H. Ginsberg, M. D. Schlesinger

The Bureau of Mines studied single - step catalytic vapor - phase hydrogenation of oils derived from coal and oil shale . Treatment of middle oil , from hydrogenation of bituminous coal , gave good yields of gasoline with a German - made molybdenum- zinc - chromium catalyst . The Bureau also achieved good results with duplicates of this catalyst made from domestic raw materials . In one set of experiments with the German catalyst , 38 to 52 wt pct of feed was converted to gasoline . The total liquid product was 91 to 98 wt pct of the feed . Not all this gasoline can be claimed as production , however , because about 20 pct of the feed was in the gasoline range , and part of it undoubtedly survived the hydrocracking treatment . Hydrogenation of crude shale oil in the presence of cobalt molybdate catalyst produced a total liquid product of 89 wt pct of feed . The hydrogenation converted 27 wt pct of feed to gasoline and 44 wt pct of feed to diesel fuel . The remaining liquid product , 18 wt pct of feed , was residue boiling above diesel fuel . The gasoline was of poor quality , with an octane number of 39.1 . The overall product seemed a suitable feed stock for a conventional refining operation . Coker distillate hydrogenation , using a cobalt molybdate catalyst , gave a total liquid product of 97 vol pct of feed ; of this product 60 vol pct was jet fuel and 40 vol pct was diesel fuel . High nitrogen and sulfur in all three of these raw materials severely poison the usual refining catalysts . Thus , the common objective in these

Jan 1, 1964

By G. St. J. Perrott, G. W. Jones

"In cooperation with The Edison Electric Illuminating Co. of Boston, Mass., a survey was conducted in 1929 and 1930 by the United States Bureau of Mines to determine the general hazards of combustible gases and vapors in manholes and other underground openings owned by this company. The territory served approximates 650 square miles and includes 46 cities and towns. The transmission and distribution systems are on overhead construction and underground wires and cables run in underground conduits and manholes. There are 17,000 manholes on the system, and also an area in Boston proper served by the Edison tube system. These conduits and manholes are laid in various types of streets from the most modern type of cement roadbed to the older type of loose macadam. The conditions as found could be considered as typical of any public utility in the electric-light and power field. The survey extended over a period of about a year beginning in June, 1929, and ending in July, 1930, and during this time 1,765 different manholes were tested and a total of 4,068 tests were made.Previous to starting the actual survey, one of the writers, G. W. Jones, spent considerable time in Boston determining the best methods of practical· test procedure. In this work cooperation was given by John Campbell, superintendent, special service department, who for a number of years has been making a study of explosions in underground street areas and preventive measures in Boston and various cities.After this preliminary investigation the tests were continued by employees of the Edisun Company. Copies of all records of tests were forwarded to the United States Bureau of Mines Pittsburgh Experiment Station so that the writers were in close touch with the progress of the survey, and changes could be made in the test procedure whenever deemed necessary."

May 1, 1931

By Robert M. Becker

Part 5, the last of this series, deals with the theoretical confirmation and application of results developed in parts 1 and 2. The bulk-sampling variances of Hassialis and Kassel and Guy are compared with those in part 2, both as to formulation and as applied to ores and coal. The results provide confirmation for much of the development in part 2. Examples are presented for determining the reliability of bulk samples with respect to various measurable characteristics. These characteristics include, for example, assays for elements or compounds and particle surface area. The bulk samples considered consist either of a given weight, a given volume, or a given number of particles. In addition to problems of sample reliability, some of these examples may also be applicable to quality control. Several possible applications of results developed in parts 1 and 2 are outlined. These include tests for random data, degree-of-mixing indices, and particle-fineness indices.

Jan 1, 1966

By George R. Ingham

This paper is one of a buries being prepared by the Bureau of Mines on mining methods and costs at various mines in the United States, and is a description of the mining practice at Ajo, Ariz., where the New Cornelia Branch of the Phelps Dodge Corporation mines copper ore from an open pit, and operates a concentrator for the treatment of the ore thus mined. ACKNOWLEDGMENTS The authors wish to express their appreciation to M. Curley, manager of the New Cornelia Branch of the Phelps Dodge Corporation, for his review of this paper and permission to publish it. They also wish to acknowledge the assistance given by W. C. Lawson, assistant engineer, in the preparation of the paper.

Jan 1, 1932