Search Documents

By W. C. Sanborn

The Bureau of Mines program of investigation and development of domestic mineral deposits had as its wartime objective the most effective immediate utilization of these resources in the interest of National security. Since the war, the results of individual projects are being prepared for publication as rapidly as practicable. Numerous chromite deposits were examined, among them those of the French Hill Mine in northern California. Situated 16 miles east of Crescent City, 76 miles from the nearest railroad shipping point at Grants Pass, Oreg., this deposit had a recorded yield of about l4,000 tons of metallurgical-grade chromite to the end of 1943. By the end of 1946, total production was more than 25,000 tons, averaging 43 percent Cr2O3, with a chrome:iron ratio of about 2.5:1.

Jan 1, 1948

By Alan R. Buehler

A mineral survey of the 67, 110-acre Raven?s Eye WSA (Wilderness Study Area) in the north-central Snake River Plain of Idaho was conducted by the U.S. Bureau of Mines in 1985, at the request of the Bureau of Land Management. The WSA is in Blaine and Lincoln Counties; the northwest corner is about 1 mile east of Carey, 10. A search of county mining claim records indicated that no claims have been located in the WSA. Basaltic lava is the only rock type exposed within the WSA. A platy variety of lava (slab pahoehoe) occurs that is produced from other lava fields in southern Idaho. The material is marketed as decorative stone, used for wall veneers, and retails for approximately $125/ton. Within the W5A, approximately 18,000 tons of indicated reserves are concentrated in two areas, and a total of 12,000 tons of indicated subeconomic resources were found at six other localities. An additional 10,000 tons of inferred subeconomic resources are unevenly distributed over the remainder of the WSA.

Jan 1, 1986

By H. E. Powell, T. E. Hill, W. A. Calhoun

The object of this investigation was to determine the effectiveness of certain cationic flotation collectors , Ethomeens , in recovering fine particles of lead minerals from mill tailings at a grade equal , at least , to that of the mill feed ( 1.7 percent lead ) . The Ethomeens , derived from tertiary amines having one fatty alkyl group and two polyoxyethylene groups attached to the nitrogen , were evaluated by bench- scale flotation tests . The 14 Ethomeens tested consisted of four groups : Coco amine , soybean amine , tallow amine , and stearyl amine . The best results were obtained with coco amine C / 12 , soybean amine S/ 15 , tallow amine T / 12 , and stearyl amine 18/20 . From a feed containing 0.23 percent lead , rougher concentrate grades of 2.12 to 3.89 percent lead were obtained , with recoveries of 17.3 to 27.5 percent of the total lead . Some of the lead mineral particles recovered had diameters of less than 1 micron . In comparative tests , the Ethomeens , or polyethoxylated amine types of cationic surface active agents , were more selective than conventional xanthate collectors for flotation of slimed lead minerals .

Jan 1, 1964

By Jacqueline A. McClaskey

The U.S. Bureau of Mines (USBM) Information and Analysis Directorate collects worldwide data on virtually every commercially important non fuel mineral commodity. These data form the base for tracking and assessing the health of the minerals sector of the U.S. economy. The USBM's data collection activity was instituted by the 47th Congress in an appropriations act of August 7, 1882 (22 Stat. 329), which placed the collection of mineral statistics on an annual basis. The most recent authority for the USBM survey activity is the National Materials and Minerals Policy, Research and Development Act of 1980 (Public Law 96-479, 96th Congress). This act strengthens protection for proprietary data provided to the U.S. Department of the Interior by persons or firms engaged in any phase of mineral or mineral-material production or consumption.

Jan 1, 1993

By C. Harry Benedict

This paper, describing the leaching practice at the Calumet and Hecla mills, Lake Linden, Mich., is one of a series on milling methods and costs being published by the United States Bureau of Mines. GENERAL DESCRIPTION The reclamation plant is located along the shores of Torch Lake at a slightly lower level than the concentrator itself. The entire location of the original concentrator, in connection with the present reclamation plant, has been ideal, lore particularly as the leaching and flotation departments are common to both units. After 15 years of operation and with the reclamation sands just a little more than half exhausted it would appear that the remaining life of the deposit could be worked by the present plan, without decided changes or renewals of plant or equipment.

Jan 1, 1930

By W. H. Lewis

This Bureau of Mines report and its companion report (Information Circular 9073) have been prepared as a complete reference on underground coal mine lighting. This report discusses system design criteria and procedures, data and specifications to aid in selection of suitable mine lighting hardware, and guidelines for system installation and maintenance. Topics include light measuring techniques and instruments, illumination regulations for underground coal mine environments and equipment, lamps and ballasts, available mine lighting hardware, design and evaluation of coal mine illumination systems, and installation and maintenance of a mine lighting system.

Jan 1, 1986

By Robert L. Chufo

This paper describes a general purpose imaging technology developed by the U.S. Bureau of Mines (USBM) that, when fully implemented, will solve the general problem of "seeing into the earth." A first generation radar coal thickness sensor, the RCTS-1, has been developed and field-tested in both underground and highwall mines. The noncontacting electromagnetic technique uses spatial modulation created by moving a simple sensor antenna in a direction along each axes to be measured while the complex reflection coefficient is measured at multiple frequencies over a two-to-one bandwidth. The antenna motion imparts spatial modulation to the data that enables signal processing to solve the problems of media, target and antenna dispersion. Knowledge of the dielectric constant of the media is not necessary because the electrical properties of the media are determined automatically along with the distance to the target and thickness of each layer of the target. The sensor was developed as a navigation guidance sensor to accurately detect the coal/noncoal interface required for the USBM computer-assisted mining machine program. Other mining applications include the location of rock fractures, water-filled voids, and abandoned gas wells. These hazards can be detected in advance of the mining operation. This initiating technology is being expanded into a full threedimensional (3-D) imaging system that will have applications in both the underground and surface environment.

By Charles Will Wright

This paper has been written to aid the owner of a small gold mine or prospect in preparing a report on his property for the purpose of interesting capital. If an owner can afford to do so, he should employ a mining engineer of recognized standing and experience to examine and report on his property, but many owners of small -mines and particularly of prospects cannot make the expenditure required for this. Further, many of them do not know how to prepare a description which will cover those features of a deposit on which a potential investor promises his opinion as to its worth. If such an owner is convinced that he possesses an orebody of sufficient grade and size to warrant the required expenditure for a thorough investigation and wishes to present his property to prospective investors, then the following suggestions concerning the proper way to sample his deposit, estimate the tonnage of developed and probable ore, and prepare a report may be of assistance.

Jan 1, 1933

By A. B. Coates, J. E. Crawshaw

"The use of such methods and apparatus as the Dautriche method and the Mettegang recorder for the determination of the rate of burning of black blasting powder and other strictly burning explosives has been found to give such erratic results that no reliance can be placed on the data thus obtained. Consequently, investigators of those factors which may affect the burning rate, such as size of grain, absolute density, chemical composition, and means of ignition have had to rely mainly on observations made during practical use for determination of the part played by each. Such tests are very difficult of interpretation.The purpose of this paper is to describe a method used by the explosives division of the Bureau of Mines for the investigation of such explosives and to present the results of an investigation using that method.The investigation was concerned with the effect of grain size, initial pressure, and means of ignition on the rate of burning or rate of pressure development of black blasting powder as compared with pellet powder.The Bichel pressure gauge was used for these tests, with the slight modification to the apparatus and method described in U. S. Bureau of Mines Bulletin 15.4 These modifications consisted of reducing the speed of the revolving drum on which the time-pressure record is taken, measuring the speed of the drum by a belt-driven tachometer, and introducing an induction coil in series with the electric squib or electric detonator to mark on the time pressure record the instant at which the squib or detonator was fired."

May 1, 1929

By R. J. Fantel

To determine the availability of phosphate rock from domestic re- sources, the Bureau of Mines evaluated the potential production of phosphate rock from the demonstrated resources of 130 mines and deposits. The evaluation included an estimation of resources, engineering methods, and capital and operating costs, and an economic analysis to determine each operation's average total cost of production over the life of the mine, including a 15-pct discounted-cash-flow rate of return on all investments. Quantified but not evaluated in this report are substantial phosphate resources at the inferred and hypothetical resource levels. The 130 mines and deposits contain 6.4 billion tons of recoverable phosphate rock product, about 20 pct from producing mines. At total production costs of under $30 per ton in January 1981 dollars, about 1.3 billion tons of phosphate rock product is potentially available, over 90 pct from producing mines. This study suggests that production from low- cost, high-grade phosphate mines now in operation will decline during the next decade, and new higher cost, Lower grade mines will have to be developed to satisfy demand into the next century, In addition to the demonstrated resources evaluated in this study, 7 billion tons of inferred-level and 24 billion tans of hypothetical- level phosphate rock are potentially recoverable, which, in part, includes material containing high amounts of magnesium, Much of this material could likely become available in the near future.

Jan 1, 1983

By B. W. Madsen

Research by the Bureau of Mines has shown that treatment of open pit waste by crushing and sizing followed by flotation of the fines and leaching the coarse fraction results in greater metal recoveries than obtained by leaching only. Tests with a chalcocite-bearing quartz monzonite mine waste sample that had been crushed to minus 6 inches and screened on 1/2 inch yielded copper and silver recoveries of 71 and 22 percent, respectively, by the combined flotation-leaching process, compared with 48 percent of the copper and no silver recovered leaching the run-of-mine material. Copper was more readily leached from the coarse material with the minus 1/2-inch fines removed than from material with the fines included. The improved leaching was attributed to improved permeability and the associated improved circulation of air to the interior of the ore column. Cost estimates showed that the proposed intensive treatment of mine waste will require a greater capital investment and higher annual operating costs than conventional milling and dump leaching process. However, the income from the additional metal production offsets the increase in capital investment and operating costs, resulting in additional profit.

Jan 1, 1975

By A. E. Schwaneke

Plans and specifications are given for constructing a quartz composite oscillator designed to measure internal friction in metals and alloys . The characteristics of the system are listed , and detailed procedures for its operation are explained . Typical measurements on manganese - copper alloy , on single - crystal magnesium , and on polycrystalline magnesium are shown to illustrate applications of the system .

Jan 1, 1964

By Raymond B. Ladoo

Garnets are usually found well crystallized in the cubic system , the principal forms being rhombic dodecahedrons , tetragonal trisoctahedrons or combinations of the two , and hexoctahedrons . They also occur as rounded disseminated glassy grains and in compact massive , laminated or gramlar aggregates . They vary greatly in color , but the most common garnets , almandite and andradite , are most often found of a dark red or reddish brown color .

Apr 1, 1922

By Ott F. Heizer

This paper describing the mining practices at the mines of Massachusetts, Massachusetts Co., Inc., at Mill City, Nev., is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in tie various mining districts of the United States. The author acknowledges the assistance of William C. Vanderburg, associate mining engineer, U. S. Bureau of Mines, in the preparation of this paper.

Jan 1, 1930

By W. G. Pariseau

The U.S. Bureau of Mines has been conducting a series of rock mechanics investigations at the Lucky Friday Mine in the Coeur d'Alene Mining District of northern Idaho. The present study uses rock deformation measurements to validate and calibrate a geomechanical model of the experimental Lucky Friday underhand longwall (LFUL) stope on the 5,100-ft level of the Lucky Friday Mine, Mullan, ID. The calibrated three-dimensional, finite-element model and measurements of rock mass displacement show a correlation of 0.795. The calibration reduces rock mass modulus to 14 to 17 pet of laboratory values and rock mass strength (with an energy rule) to 37 to 41 pet of laboratory values. This model suggested that stress-related ground control problems would be encountered west of the stope where the vein makes a right-angle turn and then splits. Rock burst activity was concentrated in this area during mining of the LFUL stope.

Jan 1, 2010

By D. E. Wolfson

This report presents 900° C BM-AGA carbonization and related data for coals from the principal beds of Nicholas, Randolph, and Webster Counties, W. Va. Thirty-three samples from nine coal beds in three counties were car-bonized at 900° C in the l8-inch-diameter BM-AGA retort, data from which have been correlated with industrial production. Host of the samples were chemically suitable for metallurgical use, and their coking properties were satisfactory. Except for four of the Lower Kit-tanning samples, the ranges of constituents in the coal seams were 1.8 to 9.0 percent ash and 0.4 to 1.1 percent sulfur, values within the range of accept-ability for metallurgical coals. Coke strength indexes were normal for Appalachian coals of similar rank, and the tumbler stability indexes of the coke ranged from 35 to 57.

Jan 1, 1969

By Stephen C. Tadolini, Thomas M. Barczak

Roof support systems, longwall shields in particular, have persistently grown in size and capacity for the past 25 years. Why is this? Is it a good thing or is it unnecessary? What are the consequences of this “bigger-the-better” design philosophy? Rarely do we see a “one size fits all” approach to roof support except when it comes to longwall shields, where the historical trend for new procurements is to simply purchase the highest capacity support you can buy. Does high capacity ensure failures will not occur? The answer is no! The highest capacity tailgate supports are typically the ones that fail the most often. What does this tell us? It tells us that there are fundamental aspects of support design and ground control that we still do not understand or recognize when designing a support system. This paper provides an interesting evaluation of these issues and proposes a different approach to support design that attempts to match the support performance characteristics to the ground behavior. Along the way, some of the old premises of support design will be discarded, and new “controversial” ideas developed. Thinking outside the box never hurt any industry. Mining has made it a common practice.

By E. R. Cole

This Bureau of Mines investigation was prompted by the need forr a stable anode for electrowinning metals, particularly zinc and copper, from acid solutions. The polarization behavior of Pb-Ag (1 pct Ag) anodes in H2SO4 and fluoride solutions was determined as the first step in the development of such an anode. A Luggin capillary, dc power supply, high-impedance voltmeter, and other equipment standard to an electrochemical laboratory were used in this study. It was determined that during polarization, a relatively hard, stable coating of Pb02 was formed on the surface of the lead-silver anode and the rate of formation of this coating was considerably enhanced by the presence of fluoride ions in solution. Subsequent investigations at the Bureau of Mines Rolla Research Center resulted in the development of a Pb02-coated titanium (Pb02-Ti) anode. Results of this effort were presented in Bureau of Mines Report of Investigations 8111. Additional data resulting from extensive testing of the Pb02-Ti anodes, as well as process improvements and innovations, are included in this report. The anodes were considered generally unsatisfactory for zinc electrowinning because of lower conductivity, higher oxygen overvoltages, and shorter in-cell life as compared with the Pb-Ag anodes now being used in industry. However, the PbO2-Ti anodes were used successfully to oxidize waste chromium solutions and to electrowin copper.

Jan 1, 1981

By A. Wahib Khair

"This article first describes the impact of respirable dust on the health of miners in underground coal mines in the United States of America. Second, it identifies the major sources of dust generation, namely cutting tools in the road headings. Two surveys associated with cutting tools were made to determine the useful life of these cutting tools, and to determine the effect of cutting tool wear on productivity of the continuous miners. Third, this article presents the results of a series of experiments carried out in the Rock Mechanics Laboratories at West Virginia University in order to study: 3.1 the effect of cutting tool rate of wear on respirable dust generation, 3.1.1 the effects of rock materials on tool wear and respirable dust generation, 3.1.2 the effect of cutting tool geometric parameters on respirable dust generation, and 3.1.3 the effect of tip materials used in the cutting tool on respirable dust generation. Recommendations in regard to cutting tool design are also presented in this paper.Silica and coal dust are the two major elements affecting the health of underground miners. According to Lemen [1] approximately 1,500 men died due to breathing in silica dust in 1936 while tunneling through a mountain of mostly silica, near the town of Gauley Bridge, West Virginia. Coal dust resulting in lung diseases in one of the major health hazards in underground coal mines. The impact of black lung on miners, coal workers' pneumoconioisis (CWP), has ranged from 16,000 to 23,000 each year since 1982 [1].The trend for conventional mining to continuous machine cutting of coal, using more productive machinery, is inexorable. Intolerable level of dust generated at the face is an indication of inefficient coal/rock cutting by these machines. The federal goverment of the United States paid about 11.7 billion dollars in workmen's compensation to more than 470,000 miners with CWP [2]. Bieniawski and Zipf [3] reported that annual benefit payments were about 2 billion dollars. The enactment of the Health and Safety Act in 1969 in the United States triggered the initial investigation into coal cutting mechanisms and cutting tool designs.The surveys concerning the utilization of cutting bits and performance of continuous miners in underground coal mines were made in order to have first hand information about bit consumption and coal produ¬ction.Three types of used bits, commonly utilized cutting tools on continuous miners, were collected from different coal mines. The used bits were grouped into symmetrically and asymmetrically worn bits. Distribution analysis for weight loss and conical height loss was done. Details of the results are presented elsewhere [4], here the results are summarized briefly. The analysis shows that approximately 50% of the collected bits have worn asymmetrically, which shows that many bits do not rotate properly during cutting. Analysis of the distribution of bit wear showed that the degree of bit wear varied from one type to another and with mining conditions. On average, the weight loss of the used bits was 4% to 7% with a maximum of 31%. Correspondingly, the loss of the conical height was observed to vary between 11% and 23% with a maximum of 71%. Figure 1 shows typical data associated with some of the used bits."

Jan 1, 1998

By Lloyd A. Morley, Robert Stefanko

Table

Jan 1, 1974