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By G. E. McClelland

As part of its mission to assure an adequate domestic supply of metals essential to the Nation's welfare, the U.S. Department of the Interior, Bureau of Mines, investigated a particle agglomeration technique as a means for improving the flow of leaching solution through heaps of clayey or finely crushed, low-grade, gold-silver ores. Bench-and pilot-scale experiments showed that the percolation rate of cyanide leaching solution was markedly enhanced by mixing the ore with a portland cement binder, moistening the mixture, and mechanically agglomerating and aging the feed prior to heap building and leaching. The rate of gold and silver recovery markedly increased because of the increased, uniform percolation of leaching solution through the agglomerated feed. The use of concentrated cyanide solution instead of water during the agglomeration procedure decreased the leaching time required to obtain maximum recovery. Results of bench-and pilot-scale experiments are discussed.

Jan 1, 1981

By John H. Soulé

"INTRODUCTION Spodumene and lepidolite were shipped from the Harding pegmatite deposit, Taos County, N. Mex., in the period from 1930 to 1930. Tantalum minerals were noted as early as 1924 and described in 1931 3/ but no tantalum ore was shipped until 1942. The deposit was mapped and studied by geologists of the Federal Geological Survey and engineers of the Bureau of Mines late in 1942 and early in 1943, and a Bureau of Minus exploratory project was carried out in 1943. 4/ Thu following report presents the results of that project.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Minos has as its primary objective the more effective utilization of our mineral resources to the end that they make the greates possible contribution to national security and economy. It i the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lovell B. Moor, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallugiical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, Assistant Director."

Dec 1, 1946

By James S. Browning

The Bureau of Mines conducted laboratory batch and pilot plant flotation tests to determine the technical feasibility of recovering commercial-grade mica from a California micaceous schist. Best results in the laboratory batch tests were obtained using sodium carbonate and sodium silicate for pH control and quartz depression, and a combination of fatty acid and cationic reagents as the mica collector. In continuous pilot plant flotation tests, an alkaline fatty acid-cationic method recovered about 70 percent of the mica in a concentrate analyzing 95.6 percent mica.

Jan 1, 1965

By John Nagy

The Bureau of Mines examined explosion development in a closed spherical vessel, mathematically correlating flame travel, pressure, and time with parameters defining the reaction. The model assumes that burnt and unburnt zones are separated by a thin, radially moving flame front. Isothermal and adiabatic systems are considered. Correlation with gas and dust explosion data is better for the adiabatic system, but the isothermal development is simpler and in reasonably good agreement. Interpretation of the explosion phenomena is facilitated by expressing the rate of mole change in the flame front in terms of elementary parameters. This expression is developed by examining the components of spatial-flame velocity.

Jan 1, 1969

By W. W. Simpson

The Bureau of Mines conducted research to determine the effects of potassium trithiocarbonate (KTTC), a degradation product of potassium ethylxanthate (KEX), on flotation of chalcopyrite and molybdenite. Small amounts of KTTC were identified in fresh and aged solutions of KEX using thin-layer chromotography. Hallimond tube flotation tests on pure minerals showed that KTTC acts as a weak collector for chalcopyrite. Both KEX and KTTC tend to depress molybdenite, but the depression effect is easily overcome by addition of a small quantity of fuel oil. The results of the Hallimond tube tests were confirmed in batch flotation tests using a porphyry copper ore.

Jan 1, 1983

By F. S. Crawford

Interesting data on electric blasting and sinking of the Montreal No. 5 shaft of the Montreal Mining Co., Montreal, Wis., were obtained during the sinking of the last 877 feet of this shaft. Several unusual features and safety practices are also to be found in the Montreal mine. The Montreal shaft was sunk 2,156 feet from August 16, 1921, to May 1, 1924, and 877 feet from October, 1927, to June, 1928. The first section of the shaft was supported with steel sets spaced 5 feet on centers; and instead of lagging the walls were covered with three-eighths of an inch of gunite where Greenstone was encountered, and where quartz-slate was found (from the surface to the 12th level) the walls were lagged with tamarack lath treated with carbolineum, a preservative.

Jan 1, 1929

By Carl Belser

In 1925 the Park Utah Consolidated Mines Co., after several years of experimental work, installed a system for signalling from cages which has been operating efficiently and with low upkeep costs for the post 19 years. The system was adopted for a large western metal mine but was later abandoned be arse of the constantly shifting shaft alinement. Recently the system has been studied and probably will be put into service at two other large mines. One of the principal reasons wry the system has not boon adopted more widely has been the lack of adequate details both as to the desirability of having such a system and as to its construction and operation. Previous signaling, systems contained undesirable features, such as charged bare wires extending the full length of the shaft. Under the direction of O. N. Friendly, then general superintendent of the Judge Mining & Smelting Co., the present system, entailing the use of a samll current at low voltage, was gradually developed. Many of the refinements in the system wore contributed by Leonard Wilson, consulting electrical engineer, Salt Lake City, Utah.

Jan 1, 1945

By John P. Powell, J. L. Eakin

"INTRODUCTION AND SUMMARYNowata County, in the northeast corner of Oklahoma, is one of the principal oil-producing counties of this stripper area. Many fields in the county were opened and much oil was produced before statehood. The location of the major fields, as defined by the Oklahoma Corporation Commission, 2/ the outline of the areas of water-flooding activity, and the location of the several projects described in detail in this report are shown in figure 1.There was some drilling in the county earlier; but it was not until after 1904, when the Secretary of the Interior confirmed as valid the leases granted by the Cherokee Nation, that the major drilling activity began. Initial development in this part of Oklahoma was in the Chelsea field in Rogers County, which adjoins Novata County on the south. The activity spread rapidly northward to the Alluwe and Coody's Bluff fields, and then to the Nowata-Claggett field. Continued exploration resulted in discovery of the Delaware-Childers field, where some wells having an initial production of 1,000 barrels daily were completed. Fields discovered and developed during the next few years included the Lenepah (Elliott), Adair, California Creek, Curl Creek, Woody, and South Coffeyville. The oil-production history of Nowata County is shown in figure 2. In assembling the data for a production curve, it was found that the combined production records for Nowata and Rogers Counties were available for 1914 to 1951, inclusive, and that records for the individual counties were available only from 1926 to 1951, inclusive. The early production figures for the counties from 1905 to 1914, inclusive, except for 1909, were calculated from the initial production statistics of the Federal Geological Survey mineral resources bulletins and production data assembled by C. H. Beal. 3/ The production values for 1905 to 1926 for Nowata County were obtained by dividing the total production for the two counties by a percentage factor derived from known facts regarding the oil industry in the area. Production figures for the individual counties from 1926 to 1933, inclusive, were obtained from the files of the Oil and Gas Journal, and the figures from 1933 through 1951 were obtained from monthly reports of the Oklahoma Corporation Commission."

Jun 1, 1952

By John E. Kelley

Laboratory equipment, which simulates abrasive impacts between steel and minerals that might be present during pneumatic transport of coal, was used by the Bureau of Mines to characterize the potential explosion hazard of such collisions in an atmosphere of fine coal dust, air, and methane. A variety of coal mine rock materials, including sandstone, limestone, and pyrite-bearing limestone, were impacted with specimens of pipeline steel. Tests were con-ducted in atmospheres containing zero to 6.4 vol-pct methane mixed with zero to 300 mg/l coal dust. Coal dust in air alone was not ignited by abrasive impacts, but additions of as little as 1 vol-pct methane to the coal dust and air mixture resulted in ignitions. Steel impacting against sandstone caused ignitions in mixtures of coal dust, air, and methane, and the probability for ignitions increased with an increase in methane. No ignitions occurred with impacts of steel on lime-stone or pyrite-bearing limestone, even when large showers of sparks were produced. Studies of the effect of tangential collision velocity showed that no ignitions of coal dust, air, and methane occurred below 900 fpm (4.57 m/sec). Ignitions in coal-air-methane mixtures were found to be caused by a hot friction-induced smear on the impacted rock at the impact site rather than by sparks. High-speed photography was used to verify this observation.

Jan 1, 1976

By Michael G. Zabetakis

The process of ?gasfreeing? has been defined3/ as "* * * the removal of oil and vapors from tanks, pipelines, and compartments to render such spaces safe for the intended work," Generally, part or all of a vessel is gasfreed for one of several reasons: Periodic cleaning; tank inspection or repairs; shipyard overhaul or major repairs; or change of cargo, Curing the gas- freeing, flammable or explosive4/ mixtures (mixtures through which a flame can propagate after ignition by an open flame, heated object, electrical charge, or other means) may be produced. These mixtures create an explosion hazard, as the pressures produced after their ignition are often great enough to completely demolish the vessel and kill all those aboard, This paper outlines a study by the Federal Bureau of Mines of the gas explosion hazards likely to be encountered while gasfreeing a vessel compartment. To better understand these hazards it will first be necessary to review the language used in gas- explosions work. This language is considered in the following sections. Inert gases such as carbon dioxide, nitrogen, water vapor, and others can be used to decrease the range of combustible-vapor concentrations in which flammable mixtures are formed. Sufficient quantities of such gases can often be added to cause a mixture that originally was flamable to become nonflammable. Unfortunately, the use of water vapor in this application is complicated by the fact that elevated temperatures are required to keep the water in the vapor state. In practice, it may be difficult to maintain these elevated temperatures throughout the space (such as a cargo tank) to be inerted for any length of time. Accordingly, where other inert gases are not available, it may be desirable to gasfree a Lank by using heated air. To do this, the combustible vapors should be flushed as quickly as possible from the space to be gasfreed. In a properly designed system, large tanks were gasfreed with a littlee as 6 volumes of air per volume of tank capacity.

Jan 1, 1961

By J. D. Tolman

In view of present interest in a revival of gold mining enterprises, papers dealing with the development of small gold properties are apropos. The present paper deals with the operation of a small gold property in the exploration and development stage, mining and milling 25 tons of ore daily, and indicates what may he expected in the way of mining costs under northern climatic conditions, by practicing rigid economy, at a property where disproportionate overhead costs are unavoidable bacause of the small rate of production. The output of this prospect is treated in a small amalgamation plant which has been described in a previous circular.. HISTORY Prospecting in the district was begun in 1909, and by 1911 the adjoining mines, Hollinger and McIntyre, were in operation. Actual work was begun on the Rochester claim in July, 1922, and carried on through 1924. The property was closed until 1928 when the present company took it over, together with the other holdings of the Canadel Mining Co. A small mill was started as a pilot plant on March 24, 1929, and is still in operation.

Jan 1, 1931

By G. D. Coe

Float-and-sink tests indicate what results are obtainable by gravity separation and rare therefore an invaluable adjunct to most coal-cleaning processes. However, it is difficult to make a direct interpretation of float-and-sink data on coal, and several systems for interpreting them have been proposed. Of these, that developed and used extensively by Bird3/, Yancey4/, and Gandrud5/ is considered by the author to be the most satisfactory. It makes use of four interrelated curves (hereafter referred to as be "washability curves"). These curves were explained by Bird in a paper6/ published in 1923, but his explanation has been regarded by some as not sufficiently

Jan 1, 1938

By William C. McBee

Prompted by forecasts of a sulfur oversupply, the Bureau of Mines, U.S. Department of the Interior, is conducting research on potentially large-scale uses of this commodity to extend or replace such construction materials as asphalt, cement, and mineral aggregates. Through these efforts, paving materials have been developed in which sulfur replaces up to 50 pct of the asphalt normally present and which can be prepared and placed with existing mixing and paving equipment. Laboratory properties and design methods for this direct mixing process are described along with properties obtained on small-and large-scale field demonstration projects. These properties are compared with those obtained from control materials prepared without sulfur additions. Monitoring for toxic gases during laboratory and commercial mixing and paving operations is discussed also.

Jan 1, 1978

By Irving Hartmann

The record of safety in the use of permissible explosives in United States coal mines has been excellent, due in great measure to the persistence with which research has been carried on in the Bureau of Mines, to the development of permissible explosives, and to the cooperation of mine operators and workers in using permissibles in a recommended manner and in the effective though gradual replacement of black powder and other nonpermissibles. The demand for increased rate of coal production, changes in mining conditions and minim methods, and introduction of new mining machinery have resulted in modified or new blasting practices. To keep abreast of these developments the Bureau of Mines conducts investigations under actual mining conditions at the Experimental coal mine near Pittsburgh, Pa. Several years ago an extensive study was complete to determine conditions under which the allowable charge limit for permissible explosives per shot hole might be raised from 1.5 to 3 pounds without undue risk of gas or coal-dust ignitions. As a result of the study, this increase in the charge limit was authorized under certain specified conditions in 1948,5/ greatly facilitating production schedules.

Jan 1, 1954

By George S. Rice, J. W. Paul, E. H. Denny

Data assembled by the Bureau of Mines , coupled with requests from coal companies , have emphasized the desirability of establishing standardized specifications for brattice cloth with particular respect to durability and fireproofing . Brattice cloth is a canvas or other material , often covered with some fireproofing composition , which is used extensively in coal mining for temporarily deflecting air into pillar workings and maintaining ventilation at the working faces . These specifications will be established , it is planned , through a cooperative program in which the U. S. Bureau of Standards will make a series of tests of various brattice cloths treated with respect to fire- resisting qualities and the U. S. Bureau of Mines will continue to assemble field data on the use of brattice cloth . Plans now are being made for this cooperative work. Without attempting to make a complete survey , the Bureau of Mines has made preliminary studies and investigations , and verious representative coal - mining companies have furnished detailed information . The information thus gained will be used as the basis for the cooperative investigation , but the Bureau of Mines would welcome additional information from mine operators on the character and weight of brattice cloth , conditions of use , durability , quantity employed and price . Such information should be sent to the Director , Bureau of Mines , Washington , D. C. The mine operator is interested in procuring at reasonable cost a brattice cloth with lasting fireproofing quality and of as great durability and strength as possible . There has been a lack of assembled data and knowledge regarding the subject , but the Bureau of Mines feels that this lack of knowledge may be overcome if the coal -mining companies will lend their hearty support to the cooperative investigation and submit information relative to the use of brattice cloth in their own properties . Information contained in this report is based on data obtained from coal operators in bituminous districts of Pennsylvania , Alabama , Utah , Indiana , Illinois , Colorado and Nova Scotia .

Feb 1, 1923

By G. St. J. Perrott, N. A. Tolch

"PURPOSE OF TESTSThe propulsive strength4 developed by the Cardox blasting device depends on the thickness of disk, weight of heater element, and weight of carbon dioxide charge. It might be supposed that the maximum weight of carbon dioxide that can be charged into the shell should give the greatest strength. However, according to the ballistic pendulum, the maximum weight of carbon dioxide with certain conditions of heater and disk has less propulsive strength than a smaller charge; in one condition of test a loss of 39 per cent in propulsive strength was noted. It is therefore of interest to study the effect of the variables that determine the strength of Cardox.ACKNOWLEDGMENTGrateful acknowledgment is made to A. B. Coates, associate mechanical engineer who developed the testing method for measuring pressures in the Cardox shell.DESCRIPTION OF DEVICEThe Cardox blasting device as fully described by the bureau in Report of Investiga¬tions 2920 (1929), consists essentially of hollow—steel shell, cylindrical in shape, an electrode, valve assembly, shearing disk, and discharge cap. The shell is prepared for use by inserting a heater element, closing the open end with a shearing disk, and screwing in place the discharge cap. The charge of carbon dioxide enters the shell through the electrode.The heater element is fired by an electric igniter of the match—head type. The heat released by the heater element completely gasifies the carbon dioxide and raises the pressure of the gas until it is enough to shear the disk."

Apr 1, 1931

By Benjamin W. Haynes

As part of the first-order assessment of potential manganese nodule processing reject waste materials, the Bureau of Mines estimated the physical and chemical characteristics of reject waste materials that would be generated from each of five potential process flowsheets. These processes were chosen because of their economic and technical feasibility for first-generation nodule processing. A brief description of the five processes is given to show process inputs and outputs, The physical characteristics are predicted based on land-based laterite processing where applicable, and where no land-based analog exists, on the basis of process chemistry. The probable chemical characteristics such as element content and compound form are tabulated for each process for 16 elements: As, Ba, Be, Cd, Go, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, TI, and Zn. These elements were chosen based on their presence on the toxic substance list of priority pollutants, EP toxicity criteria, and major and minor elements of economic importance (Co, Fe, Mn, and Mo). Physical and chemical analyses as well as results of the EP toxicity test of one industrially supplied pilot plant reject waste material are presented.

Jan 1, 1982

By James J. Olson

The Bureau of Mines used micro fracture density analysis of quartz grains in thin sections and diametric pulse velocity measurements along preblast and postblast cores to determine the nature and extent of rock damage produced by small (0.25-,0.50-,1.0-, and 2.0-kg) charges of high intensity explosive (C-4) in granite. Pulse velocities from the postblast cores were significantly lower than velocities from the preblast cores and, with the core logs, provided clear identification of the upper and sometimes the lower limits of most severe damage. These zones ranged from about 1.68 ft for the 0.25-kg blast to 4.16 ft for the 2.0-kg blast. Microfracture densities from postblast cores were significantly higher and more variable than densities measured from preblast cores. The microfracture density measurements showed that microscopic damage was present far past the zones of most severe damage as delineated by the pulse velocity logs and core logs. An exponential relation-ship was observed between the micro fracture density levels and the charge weight.

Jan 1, 1973

By Kenneth M. Earl

In its investigation of deposits of strategic minerals, the Bureau of Mines did some development drilling at the New Galena Deposit in an endeavor to find an additional source of supply of lead. In Bucks County, lead and zinc minerals have been found in shales over a largo area west and northwest of Doylestown. Considerable mining has been done in the vicinity of New Galena on the North Branch of Noshaminy Creek, 3 miles northwest of Doylestown. It has not been possible to obtain a satisfactory history of the New Galena mine, as there is much disagreement in statements. Most of the mining was done in open pits. Two shafts were sunk to shallow depth; one of these became part of the main pit' which is 256 foot long, 50 to 75 feet wide, and 20 to 44 feet deep. Small pits 8 to 10 foot square wore sunk on the ore zone, which extends some 1450 feet to the southwest. The rock containing the minerals is either black or gray shale. The gray material closely resembles limestone. The following minerals have been reported from the mine: quartz, ankerite, calcite, galena, sphalerite, pyrite, chalcopyrite, and bornite. Some of the galena has yielded 10 to 15 ounces of silver and 10 cents in gold per ton. The average grade of the ore as mined is not known. To investigate the downward extension of the ore shoot, the Bureau drilled two holes aggregating 373.9 feet, No additional ore was developed by this work.

Jan 1, 1950

By John A. Johnson

[Tests were conducted at the Mount Weather testing adit of the Bureau of Mines4/ on the effectiveness of spraying water along the outside of the drill steel as compared with standard wet-drilling practice. The spray equipment used in the tests was designed primarily for the control, in quarries, of dust from dry drilling with solid type drill steel. EQUIPMENT Spray equipment is made in sizes to fit different drill steel but is alike in design, the only difference being in the diameter of the ring and the number of spray holes. The device is made of cast steel and has a coating of Stellite on the inside edge that comes in contact with the drill steel. It looks like a garden spray, except that the spray holes point in only one direction.]

Jan 1, 1939