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By McHenry Mosier

This is the fourth progress report in the series on the use of detachable rock-drill bits in the metal mines of the United States. It contains comparative statistics and costs or drilling at eight mines not reviewed in previous reports, comparison of the use of detachable bits at small mines and large mines, a discussion on the life of drill rods, and general conclusions derived from an analysis of the rock-drilling practice at all the mines investigated on this survey. This paper completes the descriptions of operating practice in rock drilling at individual mines. Data on drilling practices at 28 mines are given in appendices I and II and drilling costs are shown in appendix III. Research in the fundamentals of rock drilling, including the use of detachable bits, has been undertaken by the Bureau of Mines in its testing adit at Mount Weather, Va. Reports on the progress off this investigation will be issued when results warrant their publication.

Jan 1, 1937

By K. J. Liles

This Bureau of Mines paper describes the composition and properties of drilling fluids for use in high-temperature geothermal wells, and summarizes the problems encountered with fluid use at the known major geothermal sites throughout the world. These include the western continental United States, Hawaii, Italy, Iceland, Japan, New Zealand, and Turkey. Water-base drilling fluids of 9- to 10-lb/gal weights are relied on primarily for geothermal well use, although air drilling is sometimes used. Bentonite-lignite-water systems have been used most often, and additives such as polyacrylates, lignosulfonates, and chromates are employed to improve the properties of the basic system.

Jan 1, 1976

By Pedro Lilienfeld

The objective of this program was the development, design, and fabrication of six personal-sized completely self-contained dust monitors capable of real-time as well as time-averaged monitoring of the concentration of respirable particles in coal mines, in the range of 0.1 to 100 mg/m3. The operation of these monitors is based on light scattering and passive air sampling. The design stressed overall miniaturization, ruggedness, simplicity and versatility. These instruments incorporate a single-chip CMOS microprocessor to perform all signal processing, data display and storage, and timing functions. The overall dimensions of these devices are, approximately, 10 by 10 by 5 cm.

Jan 1, 1982

In 2006, data obtained from the Mine Safety and Health Administration (MSHA) indicated a total of 935 underground (6.3%) and 13,950 surface (93.7%) mining operations.1

Jan 1, 2008

By James V. Kelly

During the winter of 1946 and the spring of 1947, the Bureau of Mines conducted an investigation and drilling program in the vicinity of the village of Fairplay, Wis. Fifteen diamond drill holes totaling 2,457.6 feet of bore were completed. This work was part of a general study of the zinc-producing area of southwestern Wisconsin and had the particular purpose of investigating a structural trend, determined by the Federal Geological Survey, in an area some distance from known ore bodies or active mines.

Jan 1, 1948

By Austin B. Clayton

The magnetite deposits of the Big Ore Bank, in Lincoln County, N.C., were mined during the reconstruction period following the Civil War. The country rock at the Big Ore Bank property consists of micaceous schists and schistose quartzite with a few beds of dolomitic marble. Magnetite occurs with micaceous chlorite schist and is often so schistose that it is hard to distinguish from associated minerals. A magnetic survey by the North Carolina Geological Survey indicated several magnetic anomalies that appeared to justify exploration. The Bureau of Mines drilled 10 diamond-drill holes, totaling 4,493 linear feet, to delineate the deposits. More than 500 sludge samples and 119 core samples were collected for analysis. The project was begun in November 1943 and completed in April 1944.

Jan 1, 1948

By Martin J. Gavin

During the present study of lubricating oils in the San Francisco laboratory of the Bureau of mines it became desirable to distill oils used in the experimental work at pressures as low as 10 mm., (mercury column) absolute. In the effort to overcome difficulties and eliminate sources of error the apparatus described below was finally developed. The distilling flask is essentially the Hempel flask used by the Bureau of Mines for the analytical distillation of petroleum3. The complete apparatus is shown in Figure 1. As air leakage at connections is an ever present or potential source of difficulty and error in vacuum apparatus, the, mouth of the flask is drawn down to one cm. internal diameter which materially simplifies obtaining an air-tight seal at this point. Before reducing the mouth, the spray screen is inserted and adjusted in position.

Jan 1, 1927

By James P. Bennett

The U.S. Bureau of Mines investigated the role of imported natural flake graphites in dolomite-carbon refractories used in steelmaking processes and evaluated carbon fibers as a potential substitute. Varying quantities (1.5-30 pct) of natural flake graphite and carbon fibers were added to test samples. The effect of the additions on modulus of rupture (75°-2,750° F), deformation under load (2,750° F), and air-slag-metal resistance (3,000° F) was studied. Carbon purity of natural flake graphite additions did not influence hot strength, deformation under load, or air-slag-metal resistance. When the quantity of 90-pct-carbon graphite addition varied between o and 30 wt pct, hot strength was highest, deformation under load lowest, and air-slag-metal wear the least at 10 wt pct. As test temperature increased from 500° to 2,750° F, the hot strength difference became less. Carbon fiber additions were limited to 1.5 pct in dolomite-carbon brick. At this level, physical properties were generally comparable to those obtained with natural flake graphite, but were below values obtained with 10-pet-f1ake graphite additions. Carbon fibers are not considered a satisfactory substitute for natural flake graphite.

Jan 1, 1989

By P. A. Richardson

The current Bureau of Mines active list of permissible explosives includes 76 brands. Eleven are gelatinous and the rest are the granular type. The list of permissible blasting devices comprises five Cardox models.

Jan 1, 1970

By Ronald S. Conti

This U.S. Bureau of Mines report discusses the results of research conducted in the Bureau's experimental mine at Lake Lynn Laboratory on the response of fire sensors to simulated mine fires, which included (1) a slowly developing coal-conveyor belt fire, (2) a rapidly burning liquid fuel-belt fire, and (3) a liquid fuel-belt fire in the presence of diesel exhaust. During these tests, several mine fire sensors were evaluated with respect to sensor placement, spacing, and type. The data indicate that smoke sensors alarm several minutes before CO sensors do; and that, in the presence of diesel exhaust, a prototype diesel-discriminating smoke sensor can successfully function without being sensitive to the diesel contaminants. The vertical placement of sensors in the entry near the fire was also shown to be critical in terms of alarm times. Additional data showed that variations exist in response time and level of response for two brands of electrochemical CO sensor. Results also indicate that early detection of fires will improve the probability of miners' escape, because of reduced smoke concentrations during the incipient stages of the fire.

Jan 1, 2010

By J. Ribovich

The current Bureau of Mines active list of permissible explosives includes 71 brands. Eleven are gelatinous, 56 are the granular type, and four are water-gel explosives, an entirely new type of ammonium nitrate-based explosive for use in coal mines. The list of permissible blasting devices comprises five Cardox models.

Jan 1, 1973

By Thomas C. Denton

The Old Reliable copper mine was first examined by Harlow D. Phelps , an engineer of the Bureau of Mines , in October and November 1942 , in compliance with a request from the War Production Board , which furnished copies of assay maps of the 100- and 200-foot levels and requested that they be check-sampled . The author and R. li. Grantham and W. D. Hughes , engineers of the Bureau , made a second and more detailed examination later , after a number of manways had been opened that were inaccessible when the first examination was made .

Feb 1, 1947

By G. B. Botsford

In August 1943 the Bureau of Mines began an investigation of the West Portal magnetite mines, which comprise the Swayze and Turkey Hill properties. The work included (1) traversing with a dip needle to record magnetic anomalies, (2) diamond drilling, and (3) sampling old mine dumps; it was completed in April 1944. The deposit consists of two parallel veins, which strike northeast and dip southeast. They carry magnetite in gneiss and schist. The Swayze mine was discovered in 1867 and closed in 1889, while the Turkey Hill mine was opened in 1872 and closed in 1887. The dip-needle survey covered 266 acres. The diamond drilling comprised 11 holes totaling 4,910 feet from which 142 samples were taken for chemical analyses. Old mine dumps were sampled at 52 points for chemical and magnetic analyses.

Jan 1, 1948

By T. A. Hendrickson

The Bohemia district, situated about 30 miles southeast of Cottage Grove, Oreg., in the Calapooia Range, has been the major producer of lead and zinc in Oregon. Sporadic production has been Maintained from the district since its early discovery about 1858. In 1942, a selective-flotation mill was built at the Champien mine, which operated for only a short time and was forced to close because of the war and lack of labor. The Champion mill reportedly has been operated as a custom mill for the treatment of ore from the Musick and Helena mines, located in the district sometime in the past. This report summarizes the results of laboratory ore-dressing studies made on ore samples from the Musick and Helena Mines.

Jan 1, 1951

By Martin J. Gavin

In an earlier paper (Karrick, Lewis, C. A convenient and reliable retort for assaying oil-shales for oil yield: Bureau of Mines, Reports of Investigations, Loral No. 2229, March, 1921. Reprinted in Eng. and Min. Jour, April 30, 1921, also in Mining & Met., May, 1921) which describes the apparatus and method used in the laboratories of the Bureau of times for assaying oil-shales, no mention is made of the quality of oil obtained when the apparatus is operated under conditions determined to be most suitable for producing highest yields of oils. So many inquiries regarding the nature of the oil have been received, that it seems advisable to present a short report on the subject. Experimental work indicates that it is possible to vary the quantity and quality of the oil obtainable with the assay retort from a given shale by varying the conditions of retorting. As an example, some figures that are averages for several closely agreeing tests are shown below.

Jan 1, 1921

By H. G. Iverson

As a part of the program of investigation of domestic sources of manganese ore, mining engineers of the Bureau of Mines examined and sampled three properties in the vicinity of Winnemucca, Nev. As the ores were too low grade for direct production of ferromanganese, they were tested for their amenability to concentration by ore-dressing methods. Two samples of ore were procured by examining engineers of the Bureau of Mines from several outcrops in the Pollard Canyon area, Pershing County, about 30 miles southeast of Winnemucca. The manganese occurs in relatively small lenticular bodies as secondary replacement deposits in chert and quartzite. The first sample represented average run -of -mine ore as exposed in the Pollard Canyon deposits. Sample 2 was composed of hand-sorted, high-grade ore.

Jan 1, 1954

By Paul A. Pierce

In 1984, the Bureau of Mines evaluated an area previously identified as having "probable mineral resource potential" for copper, lead, zinc, gold, or silver within the Elkhorn Wilderness, about 5 miles west of Winston, MT. The purpose of this study was to determine whether the mineralized structures at nearby mines and prospects outside of the Wilderness extend into and contribute to the anomalous zone and, if so, to expand the domestic supply of strategic and critical mineral resources for future needs by identifying and quantifying resources on public lands. Fifty-eight soil samples, 23 rock samples, and 1 stream sediment sample were collected in the Staubach Creek area. Overall sample analyses suggest the anomalous zone in the Staubach Creek drainage is possibly associated with -.mall pyritiferous quartz veins. These veins or veinlets may be part of a system of northeasterly-trending structures prevalent in this art of the Wilderness. However, there is not sufficient evidence to prove that identified resources outside of the Wilderness extend into it in the Staubach Creek drainage, or that economic base- or precious-metal deposits are likely.

Jan 1, 1987

By G. T. Krempasky

This report covers the installation and evaluation of lb reinforced concrete sets, 6 in each of 3 mines in the Goeur d'Alene mining district, Shoshone County, Idaho, and is the second of a series to determine the feasibility of a more permanent type of mine support. Closure measurements, where applicable, were made periodically of the concrete-set installations and were compared to the initial cross section of the sets. A different method of blocking was used at each test site; at one test site the type of blocking was changed several times during the test. Results from each test site are reported separately. No attempt was made to compare the cost of the concrete installations with the cost of other types of support used in the district. Such an evaluation of permanent types of support would require a longer period of time. At this time, tests are not complete enough to determine the applicability of underground concrete supports. However, results to date tend to confirm the general opinion that precast concrete mine supports could be used to advantage in openings that require support and must have long life, especially where decay of timber is an important factor.

Jan 1, 1963

By Albert E. Long

Preliminary experiments conducted in 1949 with a few diamond bits in which the diamonds in the bit crowns were set in hard-vector directions indicated that a substantial saving could be effected when a high percentage of the diamonds were oriented in this-manner. It was realized, however, that many additional tests would have to be performed before a positive trend could be established and the possibility of coincidence eliminated. Therefore, a long-range series of experiments was planned to investigate various phases of the problems related to the orienting of diamonds in diamond bits. This report (the third in a series) 2/3 presents the information obtained from tests conducted to investigate more fully the effects of orienting high-grade drill bort in diamond bit crowns. In these tests, the drill bort were oriented in both hard-vector and soft-vector directions in the crowns of AX-size bits. Test drilling was done in a dike of saussuritized dacite porphyry similar to a fine-grained granite in hardness e drillability.

Jan 1, 1954

By J. R. Thoenen

During the year 1927 the Bureau of Mines, at the request of a number of quarry operators, undertook to make a study of quarry operating costs in order to determine average costs for certain operating conditions and to suggest a model cost accounting system for quarry operations. A detailed questionnaire was prepared and mailed by the bureau to all quarries on its records as employing ten or more men in 1926.

Jan 1, 1929