Search Documents

By Lucia Kuizon

The Antimony RARE II area is underlain principally by Mesozoic igneous rocks associated with the Sierra Nevada batholith. The San Andreas fault zone is near the southern boundary. Metallic mineral deposits are associated with the fault zone. These deposits were formed from magmatic solutions, and tend to be along shears and fractures within the country rock. Marble and dolomitic marble deposits occur in Paleozoic roof pendants or inclusions in the Mesozoic intrusive rocks in the area (Troxel and Morton, 1962, p. 52).

Jan 1, 1982

By Wm. F. Netzeband

The purpose of this paper is to present to the operators, in other districts a detailed description of the ruining method used and the results obtained to exploiting one of the zinc-lead deposits of the Kansas-Oklahoma-Missouri district. No. 1. mine is located in the heart of the town of Picher in the extreme northeast corner of Oklahoma. HISTORY The first prospect drilling was done at No. 1 mine late in-1914, and shaft sinking was started early in 1915. Sufficient ore was developed to start construction of the mill in April, 1016, Production begin in August, 1916, and the mine s been producing, except for short periods, to the present time. The property was originally a 40-acre tract, but additional properties have been consolidated with the original one until the mine now covers 200 acres.

Jan 1, 1929

By R. Hogg, T. F. Dumm

"Abstract - With increasing interest in the physical cleaning of fine coal, there is a need for extension of the sink float analysis procedure to finer sizes. Problems arise, however, in ensuring complete dispersion of the particles in the heavy liquids. A procedure has been developed in which surfactants are used as dispersing agents, and solids concentration is minimized (using a simple formula to estimate the minimum weight needed for statistical reliability). Using centrifuges to increase separation rates and subsieve particle size analysis of the specific gravity fractions, a complete size specific gravity distribution can be obtained. Analyses have been performed on coal samples as fine as -10 µm.IntroductionTraditional gravity separation techniques such as jigging, heavy media and water-only cyclones, shaking tables, etc., have been used to remove impurities from coal ranging in size from about 15.cm (6 ln.) to about 150 µm (100 mesh). The coal washabilty or float-and sink technique ls a well-established procedure for determining the optimum extent to which a coal can be cleaned by such physical separation methods. Because of the desire to recover even finer coal fractions by gravity separation techniques, there is a need to extend the coal washabillty analysis into the ultrafine range. The purpose of this paper ls to describe some of the significant factors that influence fine particle specific gravity separation. Washability analyses have been performed on three ultrafine ( <10 µm) coal samples representing three general mining districts in Pennsylvania. Results of these analyses indicate that the washabillty technique can be successfully applied to ultrafine particles when proper care ls taken."

Jan 1, 1988

By Oliver Bowles

"Properties and Uses.Iceland spar is a name given to a pure crystallized form of calcite (CaCo3) which is sufficiently transparent and free of defects to be used in the manufacture of optical instruments. While the actual requirements are small, the degree of purity and physical perfection demanded renders it somewhat difficult to obtain suitable material.The properties of value in Iceland spar are its transparency combined with double refraction. It is used in the manufacture of polarizing microscopes, saccharimeters, colorimeters and photometers. Its most important use is in the manufacture of Nicol prisms, which constitute an essential part of every polarizing microscope. The principle governing the construction of the Nicol prism is as follows:Ordinary light in passing through a crystal of calcite is resolved into two rays of plane polarized light vibrating in planes at right angles to each other and having different indices of refraction. Thus the two rays follow different paths through the crystal. The prism of Iceland spar is cut diagonally and cemented together again with a transparent cement having an index of refraction intermediate between the two rays passing through the prism. Canada balsam is employed for this purpose. The prism is cut at such an angle that the ray having the greatest index of refraction meets the surface of the balsam at an angle greater than the angle of total reflection, and it is thus deflected to the side of the prism, while the second ray passes through. Thus one of the rays is eliminated and polarized light vibrating in a single plane is obtained."

Apr 1, 1920

By Richard F. Link, George S. Koch

Through the use of statistical methods, estimates of metal content and tonnage of an ore body made by using data from 18 diamond-drill holes are compared with actual values established with data from 1,829 drift samples. The reliability of the estimates made from the drill holes is assessed in several ways. The relationship of metal content (assay-width product) to grade is explained. It is concluded that useful estimates can be made from 18 drill holes provided that reasonable assumptions are made and certain risks accepted. The ore body investigated is the Don Tomas vein of the Frisco mine, San Francisco del Oro, Chihuahua, Mexico.

Jan 1, 1964

By D. L. Sawyer

The Bureau of Mines studied alumina extraction from uncalcined, kao-linitic clay at temperatures from 1000 to 2500 C using 20-or 27-wt-pct-HCI concentrations and with an acid-to-clay ratio of from 0.8 to 1.4 times stoichiometric. Autogenous digestion pressures ranged from atmospheric pressure to about 900 psia. Extraction of 96 pct of the alumina was obtained by HCI leaching at temperatures and leaching times that varied from 1000 C for 120 h to 2000 C for 15 min. Hydrochloric acid stoichiometry of the reaction A1203&apos;2Si02&apos;2H20 + 6HCI + 2AICl3 + 2Si02 + 5H20 was studied at different temperatures and leaching times in a 750-mL tetrafluoroethylene-polymer-lined autoclave. A combination of high temperature and 20 wt pct excess HCI promoted rapid and almost quantitative extraction of alumina (99 pct in some tests). Additional Bureau data obtained with 35-mL tantalum bombs and leach-ing tests with added fluoride are also provided. At high temperatures, the addition of fluoride did not result in a significant improvement over HCI alone and was deleterious to the filtering properties of the digest residue.

Jan 1, 1985

By Stuart Lipoff, John E. Trombly, Paul Brien, O&apos

System objectives and design criteria for an in-mine ULF radio paging system are discussed. Coding formats, frequency and bandwidth selection criteria leading to the system design are discussed. The prototype call alert transmitter and pocket page receiver is functionally described. The report includes circuit descriptions, schematics, parts lists, printed circuit fabrication and assembly drawings. The report concludes with an estimate of the manufacturing cost for each assembly.

This Bureau of Mines report is a compilation of information on computer models of mineral commodity markets in the Federal Government, The directory was compiled by the Analytic System Working Group of the Interagency Minerals Information Coordinating Committee to support the formulation of policies related to nonfuel minerals.

Jan 1, 1984

By Ronald H. Church

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

Jan 1, 1986

By W. Hermanson

This report, which covers the period from January 16 to October 21, 1974, describes the work performed in compliance with the requirements of contract no. H0242028 and modifications 1 and 2 thereto. The purpose of the contract was to further reline and modify three of the canopies (shuttle car, loader, and roof drill) which were developed under contract no. H0220031, and to conduct further testing and demonstration of the relined designs. Modifications I and 2 involved conducting further in-mine evaluations of the face. drill and cutter canopies, also developed under contract no. H0220031. In addition to the canopy modifications, the contract involved an evaluation of an operator&apos;s seat concept for a shuttle car which was developed for the USBM by another contractor.

Jan 1, 1974

By G. W. Birge, D. E. Wolfson, J. G. Walters

Seventeen samples were carbonized by the BM -AGA pilot - plant test method and in industrial ovens . Chemical and physical properties of the samples were determined , and the physical properties of the cokes prepared by the two methods were compared . Since the capacity of the plants from which these samples were obtained is about 30 percent of the 1959 total for the United States , the data given in this report are indicative of the chemical and physical properties of blends used to produce industrial cokes and the acceptable chemical and physical properties of the resultant coke .

Jan 1, 1964

By Susan M. Moore

Many challenges are faced by workers in lower-seam (42 inches or less) mines. The lower-seam heights confine mine workers to their knees as they perform their daily tasks such as installing roof bolts, delivering supplies, repairing belt, or cutting coal. Miners working in these lower seams often consider kneepads to be their only line of defense against knee injuries. However, healthy knees do not start and stop with kneepads. Other interventions such as changing postures, proper hygiene, and work station design may also be used to reduce mine workers? risks for developing knee injuries. Incorporating these and many other interventions into a mine worker?s ?way of life? is an important step to ensuring a long, healthy career and retirement. Keeping knees healthy is also a key aspect to reducing costs in low-seam mines as the industry battles rising health care costs, and training/recruitment of replacement workers is time-consuming and costly. Educating the workforce about the possible interventions to reduce knee injury risk is a primary objective for the National Institute for Occupational Safety and Health?s (NIOSH) Pittsburgh Research Laboratory (PRL). Therefore, NIOSH researchers, along with industry and academia, developed a training package to educate the mining com­munity about some possible interventions beyond kneepads that may be used to help decrease knee injury rates. Increased awareness and simple changes are the first steps to reducing knee injuries.

Jan 1, 2008

By John P. Coughlin

The Bureau of fines has tested a portable microseismic processor recorder at the Galena Mine, Wallace, ID, both in an environmentally controlled enclosure and, with minimal protection, in a working area of the mine. In both trials the device demonstrated effective and reliable data acquisition capabilities.

Jan 1, 1985

By E. W. Parsons

Permanent support of the back is an important economic factor in maintaining a tunnel or other underground opening in condition to render the service for which it was driven. Timber has been most commonly used for support in tunneling and drifting because of its strength and ease of installation. Even when treated for decay, however, timber is subject to deterioration and, over a long period of time, should not be considered a permanent support. Concrete support or lining is permanent and has been used in tunnels of every size for many years but has been almost exclusively cast in place, a difficult, costly process. This report deals with the design and installation of precast concrete supports to combine the best features of both methods.

Jan 1, 1958

By R. W. Holliday

To determine the copper and nickel content of reported ore occurrences in the Chippewa mine near Rockmont, Douglas County, Wis., the Bureau of Mines reopened and sampled the old shaft and workings during the summer and fall of 1953. Occurrences of native copper near Rockmont and others near Gordon, also in Douglas County, Wis., are in lava flows, which extend from the Keweenaw Peninsula of Upper Michigan southwest across Wisconsin and into Minnesota. Sporadic attempts have been made to find additional economic copper deposits in these flows since profitable mines were developed in Upper Michigan nearly 100 years ago. The Rockmont and Gordon areas were explored extensively more than 50 years ago. More recently, from August 1944 to duly 1945, an occurrence near Gordon was investigated by the Bureau.2/

Jan 1, 1955

By J. R. Koehler

Effective barrier pillar design is essential for safe and productive underground coal mining. This U.S. Bureau of Mines report presents an overview of available barrier pillar design methodologies that incorporate sound engineering principles while remaining practical for everyday usage. Nomographs and examples are presented to assist in the determination of proper barrier pillar sizing. Additionally, performance evaluation techniques and criteria are included to assist in determining the effectiveness of selected barrier pillar configurations.

Jan 1, 1995

By G. Asai

The Bureau of Mines has been engaged in a program to increase the utilization of chromium by providing samples to individuals and institutions requesting chromium for research investigations. This report consists of a tabulation of the disposition of chromium samples distributed from July 1953 through June 1961; 109 requests for chromium were answered by providing chromium as electrolytic plate, powder, or wrought forms. The demand for samples reached a peak in fiscal year 1959 and declined to a relatively low level in fiscal year 1961. The largest number of requests came from individuals engaged in mechanical property studies; there were also many requests from those concerned with vaporized metal and physical properties studies. Most noteworthy application for chromium was the experimental use of the radioactive form, Cr[51], in radiotherapy of cancer.

Jan 1, 1964

By A. J. Barry

An apparatus and procedure have been developed for testing the anchorage effectiveness of slotted-type bolts. The apparatus consists of: (1) A hydrualic Jack assembly for loading the bolt and (2) a device (extensometer or cathetometer) for measuring displacement of the bolt as it is loaded. This apparatus and procedure permit measurment of anchor slip for loads up to the yield load of the bolt. Two representative makes of slotted-type bolts (a total of 94 bolts) were tested in typical sandstone and shale mine roof. Analysis of the test results showed that (1) anchorage capacities up to the yield load of the bolts can be developed in either rock type; (2) the shape of the slotted end of the bolt affects the ease with which the bolt can be driven; (3) all bolts for which the driving distance was more than 1.25 inches produced satisfactory anchorage in both rock types (thus, driving distance can be used as a criterion for satisfactory anchorage); (4) for the group of bolts that was satisfactorily anchored the anchor slip was unaffected by the type of bolt but was considerably larger in shale than in sandstone; and (5) the bolt expansion, that is, the amount the wedge expands the prongs in excess of the diameter of the hole, can also be employed as a criterion for satisfactory anchorage. Although the bolt-expansion and driving-distance results do not differ appreciably, the latter is recommended because it is easier to determine.

Jan 1, 1954

By Q. H. Forbes

"The high injury rand fatality rate in coal mining, as compared with other industries, has caused the mining industry to become more and more interested in accident prevention methods.The prevention of accidents in the mining industry is probably not as simple a problem as it is in other industries, but if the experience of coal mining companies who have taken up the work of accident prevention seriously during recent years means anything, there is little doubt that most mining companies car improve their accident records very materially.Such results can be obtained in practically all instances without adding to production costs. In fact, there is little doubt that a well-organized program of accident prevention Will bring about a 'material production cost reduction due to increased efficiency, lower labor turnover, fewer delays due to accidents, better satisfied workmen, and a direct saving in compensation costs as well as many other items of expense.The more closely a. person is connected with the work of accident prevention, the more he becomes a believer in the value of amity in human relationships and the more he is able to exercise a spirit of toleration, fairness, justness, and helpfulness toward the problems of others, whatever those problems may be. Human nature responds to just these expressions of good willAnother great and invaluable effect of working for safety, is the fact that it is building up in the mind an appreciation of that which is constructive and, conversely, in opposition to that which is destructive In other words; the person who is sincerely striving to prevent accidents because they are destructive, costly, tad injurious, is subconsciously training his mind to look on any proposition from a constructive point of view. Working for accident prevention and safety is about the finest social training any person can have. It does not make a Person a financial Wizard or an executive genius, but it does make for the highest type of citizenship.While humanitarian reasons alone should be sufficient to maze accident prevention work an important factor in every mining organization, there are other reasons as well, since it has been proved conclusively that there can be no efficiency and economy without safety, as somebody pays when safety is lacking. Every safety device pays dividends; every safety application evaded is an assessment and a loss. Dangerous conditions are the most expensive and extravagant conditions in or about a coal mine. The economic gains are of considerable interest to all coal mining companies and this is brought about as before stated--through decreased compensation rates, the reduction of labor turnover, etc."

Dec 1, 1930

By John B. Bennett

This Bureau of Mines report presents a method of standardizing forecasts of mineral consumption that attempts to resolve the problems caused by the use of different data bases, different definitions of minerals consumption, and different base years for making projections. Using this method, forecasts of U.S. and world mineral consumption, in the year 2000, for nine commodities (aluminum, chromium, cobalt, copper, manganese, nickel, tin, tungsten, and zinc) are standardized and compared. Also selected forecasts or associated growth rates are used to generate implied values of consumption for 1980-83, which are then compared to actual values of consumption for 1980-83. The economic growth predictions underlying the forecasts are examined, and some general conclusions are drawn. A description of each methodology used to generate these forecasts is given in an appendix.

Jan 1, 1986