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By Oscar Lee

"Flotation is generally regarded as a process that is only applicable to metallic minerals. However, its scope is now known to be greater than this, because some of the nonmetallic minerals are floatable, such as graphite, sulphur, and fluorite. Recent observations show that limestone may be added to the list of floatable nonmetallic minerals. Such work is being done on a laboratory scale at the Southern Experiment Station (Tuscaloosa, Ala.) of the Bureau of Mines, Department of Commerce, where experimental magnetic concentration of the low-grade iron ores of the Birmingham district is in progress. Certain experiments have demonstrated that the limestone may be floated from the magnetic log-washer tailing, and then incorporated in the iron concentrate.If the loss of lime could be prevented, some ores though low in iron and high in insoluble contain enough lime to make their concentrates self-fluxing. Since this loss in the magnetic log-washer can not be avoided, the Time must be recovered from the tailing by some method and added to the magnetic iron concentrate before sintering. Then the resulting concentrate will be self-fluxing.While seeking a suitable means of treating the tailing for recovery of lime, flotation was tried. It was at once evident that this method had possibilities, during the early part of the investigation, soap solution made from a common soap was used as a flotation reagent. The froth obtained was a fairly good lime concentrate. This result was an important clue, and led to tests with the use of such reagents as oleic acid and sodium oleate. Later, cresol, creosote, coal tar and other similar flotation reagents were tested in combination with the oleic acid and soap solutions. As a result, oleic acid and cresol used together were found to be satisfactory.The tailing from the magnetic log-washer is in excellent physical condition fur flotation. The iron ore had been ground in a ball mill to 100 mesh for magnetic concentration. Hence the bond between the lime carbonate and the other constituents of the tailing was well broken."

Apr 1, 1926

By Dennis A. Long

"The size of off-highway trucks has increased substantially over the last decade, bringing about a radical change in truck maintenance practices and procedures. As a result, surface mine maintenance mechanics today are faced with the increased hazards of working with larger and heavier tools and components and doing repairs at greater heights, thereby exposing them to a high potential for serious injury or death. Not surprisingly, the number of accidents involving truck maintenance mechanics is significantly increasing.The Bureau of Mines has assessed the haulage truck maintenance safety problem, analyzing maintenance-accident data over the 7-yr period, 1978- 84, in terms of personnel, job activities, truck components and systems, tools involved, and truck design. This assessment, based on the review and interpretation of 1,225 haulage truck maintenance accident reports, identified major factors contributing to these accidents. Overall, young, inexperienced workers are involved in most accidents. A typical maintenance accident involves a male mechanic under 33 yr old, with less than 5 yr job experience. INTRODUCTIONOver the past decade, surface mine maintenance and repair operations have changed radically. The number of maintenance personnel has grown along with the hazards of working with larger and heavier components at greater heights and with larger and heavier tools. Furthermore, transfer of skills from over-the-road vehicle mechanics is not as feasible as it once was, because of the ever increasing size of mining equipment and the complexity of its design. In short, surf ace mine equipment maintenance and repair has become increasingly sophisticated as well as labor intensive, necessitating further research and evaluation in terms of both safety and efficiency (1, 7-8) 2"

Jan 1, 1986

Reduce exposure of longwall face workers to respirable dust generated during the advancement of roof supports. Approach Identify and implement current water-application and improved support-movement practices used to lower support-generated dust. Defining the Problem Bureau studies have shown that on some longwall faces support dust can contribute over 30 percent of the respirable dust exposure of face workers. Conditions contributing to high levels of respirable dust generation during support movement are: depth of cover greater than 1,000 ft; immediate roof consisting of coal top or friable shales; and face-air velocities in excess of 500 fpm. Moreover, at most longwalls, supports are advanced on the intake-air side of the shearer as it travels with the airflow. This places the shearer operators, and in many cases the support movers, downwind of support advance, thus increasing their respirable dust exposures.

Jan 1, 1984

The dust exposure of the longwall shearer operator is usually determined by his position relative to the cutting drums. The dust generated during cutting may travel up-wind, against the primary airflow, and be carried out into the walkway where it can contaminate the intake air for as much as 10 feet outby the shearer operator's controls. Thus, both head and tail drum operators are exposed to un-acceptably high levels of air-borne respirable dust. One Solution The latest generation of long-wall shearers has features that make the use of radio remote or umbilical (hard wire) remote control relatively easy to implement. Remote control can enable shearer operators to control machines from positions that are less dusty than normal control stations. With either type, the head-drum operator can now control the shearer from a position up to 20 feet on the intake-air side of the shearer, while the tail-drum operator's station is now located across from the head drum.

Jan 1, 1984

By R. V. Lundquist

Lime-soda sinters, made and processed for recovering alumina and soda, consisted of several types of compound structures differing from the ideal dicalcium silicate and sodium aluminate. Many or these compound structures were causes for low alumina recovery and contributed to the relation or leach slurries. Presence or free lime, whether in the sinter or released by hydrolysis of sinter compounds, contributed to relation of leach slurries. Free lime tends to establish the initial viscosity assumed by a leach slurry. Previous investigations by the Bureau of Mines (1, 4)4/ and by other laboratories (5) have demonstrated the technical applicability of the lime-soda sinter process to the recovery of alumina from aluminum silicate materials. The basic concept of the process is sintering aluminum silicate materials with limestone and soda ash for the production of dicalcium silicate and sodium aluminate and then extracting the sodium aluminate by leaching the sinter in causticized liquors. Alumina is precipitated from the pregnant liquors by carbonating with carbon dioxide. Reaction in the sintering operation may be represented by the following simplified equation: A1203?SiO + 2CaCO3 + Na2C03 = 2Ca0?SiO + Na20?Al203 + 3C02

Jan 1, 1960

By John W. Frey

This paper presents one of a series of digests of foreign mining legisla- tion and court decisions which is being prepared in advance of a general report relative to the rights of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of Trinidad has been prepared from the best information available in ashington but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers to whom it is being referred through the courtesy of the Department of State.

Sep 1, 1930

By George S. Rice

"The successful use of the gas mask by the American Army it France in combatting the poisonous gases of German .shells caused many Army men to feel that the as masks were proof against any kind of gas which might be encountered. The result has been that from time to time there have been reported in the press, deaths of former army men through using their masks to enter various kinds of gases such as illuminating gas, gasoline vapor, and the gaseous atmospheres produced by mine fire. Such a case has just been reported from a mine, in Copperopolis, California, where a former Army man lost his life in descending a mine shaft filled with the fumes of a mine fire. Another man who, in attempting to rescue him, merely used a dust respirator, lost his life also.While the American type of the Army gas mask was developed by the Bureau of Mines for the War Department, and since the war a section of the Bureau's in¬vestigative force has been developing industrial gas masks for certain specificgases, the Bureau has repeatedly called to the attention of the public the fact that such masks have serious limitations and in no case should a gas mask be used in underground workings for the reason that there may be an insufficient amount of oxygen to breathe, (and the gas mask does not supply oxygen) or there may be present carbon monoxide, which the Army mask will not remove, and there always is some carbon monoxide produced by a mine fire or by a coal-mine explosion, or by a blast of dynamite or other explosive.It is true that the Bureau has been developing a mask which may take care of a small percentage of carbon monoxide, that is, one per cent and under, but in mine fires and after explosions, there may be, and frequently is, a much larger percentage of carbon monoxide in the mine atmosphere. Masks such as these, for small percentages of carbon monoxide and associated gases are for use in connection with industrial surface plants, as for example, on the top of a blast furnace or around gas producers in the open air."

Oct 1, 1920

By E. P. Youngman

The mining law of the Belgian Congo does not cover the Province of Katanga nor the District of Kivu (in Eastern Province). Regulations of the Comité Spécial du K tanga are in force in Katanga and those of the Comité National du Kivu in Kivu. The three laws differ only in detail, and grants made by the Comité Spécial du Katanga or by the Comité National du Kivu must be approved by the Ministry of Colonies. The following résumé is designed to coordinate the three sets of regulations.

May 1, 1930

By E. P. Youngman

The law now in effect (January 30, 1931) in the Netherlands with respect to the prospecting for and the developing of minerals is regulated by , or based upon , the French Act of April 21 , 1810 , "Concernant les mines , les minières et les carrières ( Bulletin des Lois No. 285) . " A second edition of a compilation ( by Drs . Ccuvee and Ritter ) of the mining legislation of Holland , including this act with other legal requirements , was published in 1928 under the title of "De Nederlandsche Mijnwetgeving , " by H. T. Tjeenk Willink & Zoon , Haarlem. In this abstract reference is made to the Act of 1810 , the Royal Decree of September 18, 1818 , the Mining Act of 1903 , and the Act of June 20 , 1924 .

Aug 1, 1931

By J. M. Stuve

Heat of solution measurements of high-purity neodymium metal and neodymium trichloride (NdCls) in 4.360 molal hydrochloric acid (HCI) were used to determine the standard heat of formation (6EPr) of NdCls? From solution data obtained, the heat of formation of NdCls (c) was computed as -248,970 ±260 cal/mole at 298.150 K.

Jan 1, 1965

By Oliver Bowles, J. E. Crawshow

A line of cordeau detonating fuse was placed in hole No. 2, no electric detonators being used in the hole. After 12 or 13 cases of 40 per cent nitro starch powder had been poured into the hole in loose form, it was found that a space of only 17 ft. remained for stemming. It was decided that space for an additional case of powder might be obtained by tamping the charge. The tamping was done with a heavy plunger, about 3 or 3 inches in diameter and 10 inches long, made of lead with an iron core with an iron eye in the top to which a 3/4 inch rope was attached, and weighing between 30 and 40 pounds. This weight was intended for use in sinking explosive in wet holes, and not for tamping. It is estimated that the tamping had continued at least 10 The quarry superintendent had gone a considerable distance for a box of powder, returned, and reached a point about 10 feet from the hole, minutes.

May 1, 1920

By H. A. Doerner

The Rare and Precious Metals Station of the U. S. Bureau of Mines has investigated several cases in which widely divergent amounts of molybdenum were reported by a number of custom laboratories to which quartered portions of the same sample had been sent for analysis . On an oxidized lead ore containing considerable vanadium and a little molybdenum , the amount of the latter reported ranged from 3.14 to 0.24 per cent M003 . The high results were due to the fact that vanadium was estimated with , and reported as , molybdenum . When analyzed by the method described in this paper , 0.15 per cent Moog was found, which is a fair agreement with the lowest figure previously reported . In another and more unusual example , a fine- grained rock containing considerable graphite was submitted for analysis . As a white residue could not be obtained by treating this material with acid , several chemists decomposed the ore by a prolonged fusion with soda ash and nitre and leached the melt with hot water in crder to insure the dissolution of any and all the molybdenum present . After precipitating and filtering the silica from the solution , acetic acid , ammonium acetate , and lead acetate were added to precipitate lead molybdate . The solution contained phosphorous derived from the ore , which precipitated as lead phosphate . The latter was mistaken for , and reported as , molybdenum. As two different chemists used essentially the same procedure , their results , although incorrect , checked . Other chemists using different methods found no molybdenum . From these and other instances it is evident that reputable and conscientious assayers may make serious errors in determining molybdenum, and even duplication of results by different chemists does not necessarily insure against error . The elements most likely to cause trouble are vanadium, tungsten, uranium , arsenic , antimony , titanium, tin , phosphorous , and chromium . The precautions necessary to eliminate these and other impurities vary with the type of ore and the method of analysis . Most texts present methods of limited application and omit or fail to emphasize adequately such precautions . No one method can be given that will best fit every case , but the following procedure has been selected as being the simplest reliable method for such occasional determinations of molybdenum in an ore as are encountered in customs work.

Sep 1, 1930

By A. C. Watts, C. A. Allen

In the No. 3 Sunnyside mine of the Utah Fuel Co. a disastrous fire started on the afternoon of August 17 , 1920 , the effects of which are still present in the mine . On account of the extent of the fire , the expense involved in reopening the mine and the opportunities afforded for determining the effects of depleted air , a description of it is worthy of record . This paper is a summary of a more complete report , prepared by the writers , which will be published by the U. S. Bureau of Mines .

Feb 1, 1922

By Thomas V. Falkie, R. Venkataramani

Table 15. Summary of Physical Characteristics of Coal and Shale from Channel Samples. Table

Jan 1, 1972

1. The Federal Mine Safety and Health Act of 1977 defines an independent contractor as "any person, partnership, corporation, subsidiary of a corporation, firm, association or other organization that contracts to perform services or construction at a mine." Contractors that perform specific types of work (e.g., shaft and slope sinking, material handling within mine property, drilling and blasting) are required to report the number of employees who perform work at coal mines and at metal and nonmetal mines.

May 1, 2003

By D. E. Wolfson

The Bureau of Mines investigated the use of preheated coal in carbonization operations. Liquor yields and coking times were reduced, coke quality was improved, and smokeless pipeline charging to coke ovens should eliminate a serious source of pollution.

Jan 1, 1972

By M. L. Fenger, S. F. Mauser

This 1s a report on an Investigation performed during Contract No. H0166069 "High and Medium Voltage Trailing Cable Splices and Connections," which presents a summary of the requirements formulated. The requirements are presented in the form of considerations for medium-voltage splices, and medium- and high-voltage couplers used in underground coal mines.

Jan 1, 1979

By Vijia K. Karra

Making sure workers within the aggregates industry go home safely each day is the goal of aggregate companies throughout the United States. At the National Institute for Occupational Safety and Health (NIOSH) researchers are contributing to NIOSH’s vision of safety and health through a fact-finding approach to reducing injuries/illnesses in various mineral sectors. Surveillance data from the Mine Safety and Health Administration (MSHA) has been the primary source for such analyses. It helps to focus research efforts on key machinery, workers, and their tasks. The crushed stone category referred to in this article is represented as crushed and broken stone in the MSHA database.

Objective Develop field measurement and computer modeling methods to predict the potential for hang-ups and structural failures in underground mine ore paws. Background Analysis of Mine Safety and Health Administration (MSHA) accident statistics has identified ore pass hazards as a significant safety problem in underground metal mines in the United Stales. Recent ore pass failures have underlined the lack or ore pass design methods ant1 standards available to both MSHA and mine engineers. Injury and fatality data for the 20-ycar period between 1975 and 1095 show that nearly 75% of the injuries were directly or indirectly related to pulling or freeing ore pass chutes, the use of hand tools, falls or broken rock, and structural failures or chutes or gates and ore pass walls.

Feb 1, 1998

Control dust generated during mining in salt mines. Approach A machine-mounted exhaust ventilation system which moves with the cutting machine from place to place was developed. The system captures the dust at the face of the heading and exhausts it downstream of the heading in the crosscut. This helps cause fresh air from the crosscut to flow over the machine operator's position, and aids in keeping the dust cloud close to the face. How It Works The system consists of (1) a circular intake hood with a 10-inch slot extending 250 degrees around the base, bolted to the gearhead; (2) 20-inch-diameter wire-wound flexible ducting to connect the intake hood to the fan (25 ft. is allowed sufficient slack for bar movement); (3) an industrial exhaust fan capable of generating 10,000 cfm with 13 inches water gage pressure at 1435 rpm; and (4) 150 ft. of collapsible 24-inch tubing for the exhaust duct which is de-played and returned In each heading by the cutter operator and/or his helper.

Jan 1, 1983