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By M. O. Magnuson

As part of an experiment in the restoration of lands strip-mined for coal, revegetation studies were conducted at three backfilled strip-mine sites in north-central Pennsylvania. The sites were subdivided into plots that were given varying amounts of lime and fertilizer. In tests conducted cooperatively with State and Federal agronomy experts, the plots were then planted with a variety of trees, shrubs, and grass-legume mixtures. Initial tree and shrub survival was not appreciably affected by lime and fertilizer applications where the spoil pH was above 4.5. Of 14 species of trees and shrubs tested, Norway spruce, black locust, Japanese larch, pitch pine, and white pine were the hardiest. The ground-cover percentage of grass-legume mixtures in the second growing season was substantially increased by using lime and fertilizer. Mixtures comprised partly of fescue were the most satisfactory.

Jan 1, 1968

By K. C. Strebig

The effect of some organic additives in diamond drilling of quartzite was investigated in the laboratory with a drill instrumented to measure the rate of penetration, the thrust, and the torque and to record each as a function of the distance drilled. A statistical plan was followed throughout the investigation, and an equation representing the bit performance was derived from the mathematical theory of reliability. The coefficient of friction in drilling increased with the use of additives, although the wear coefficient decreased. The decrease in wear associated with an increase in energy per unit volume consumed and the increase in penetration rate resulted in a net decrease in the cost per foot of drilling. A hypothesis explaining the effects achieved with the additives is given.

Jan 1, 1971

By F. E. Armstrong

An instrument using a gamma-ray backscatter technique for determining the weight-percent incombustibles content of coal dust and rock dust mixtures in coal mines has been built and tested. The unit gives a direct readout in per-cent incombustibles for coal mine dust mixtures containing between 50 and 100 percent incombustibles; calibration of the device requires using a sample of the rock dust employed; this is usually limestone but occasionally dolomite or gypsum. A small americium-24l source is used with a scintillation detector whose output feeds a rate meter. The source-detector geometry used was chosen to reduce the effects of variation in bulk density. Accuracy of the system is within ±3 percent for most mixtures. The instrument is portable and completely self-contained; the rechargeable batteries supply power for 300 to 400 determinations.

Jan 1, 1974

By Clinton C. Knox

The Townsite mine, consisting of 40 acres in the town of Cardin, Okla., is in the center of a highly productive part of the Picher-Cardin district of the Tri-State zinc and lead field. Previous to the time of the work done by the Bureau of Mines, the property had been partly explored by churn drilling, and an area-of about 8 acres in the southwestern corner had been exploited by underground workings. The Bureau of Mines investigation had as its object the more intensive development of the northern part of the property where previous drilling had indicated a possible ore deposit of commercial grade. Churn drilling by the Bureau began in September 1942 and continued to February 1943. Twenty holes totaling 4,827 feet of bore were completed. Utilizing the information gained from these drill holes, the Weidman Mining Co., lessee of the tract, sank a shaft and proceeded to the exploitation of the indicated ore bodies.

Jan 1, 1949

By C. Melvin Lepper

Microseismic energy is generated when stresses accumulated in rock formations are released in the form of fracturing. The acoustic emissions resulting from these rock fractures and movements are detectable as velocity signals in the earth near the energy source. A Bureau of Mines microseismic system that is capable of detecting the acoustic emissions from pit slope movements is described. The digital circuitry incorporated in the system allows a microprocessor program to immediately calculate and present the location coordinates for the seismic energy source in the mine pit wall. This monitoring system is compact, portable, reliable, and relatively inexpensive and rapidly provides accurate information to the mine operators about the stability of a pit slope.

Jan 1, 1982

By Scott Turner

We are here today to witness the graduation of 63 young men as Engineers in the mineral industries . It is an important occasion and one in which the public takes a keen interest , since this school has long been famous for the educational facilities it affords young men, and for the high professional standing of its graduates . : : : It is fitting that once each year we should pause to review the path the student has traveled , and to reflect upon the perspective opening before him as an engineer . I was invited to come from Washington to take part in this ceremony and to say something to these young graduates . In searching for a theme ," it occurred to me. that perhaps my best contribution would be to duscuss certain beliefs as to college training , deal with the situation in which the young engineer finds himself on graduation , touch on the new ideas of the social and political responsibilities of the engineer , and point out what he may expect to find in practice , and , above all , what he must do to orient himself properly in the mining profession and maintain the best traditions of our brotherhood . Let us first review your college days and see what they have done for you . I am told there are still many temptations in college . I know there used to be . Rest assured the same holds true in the professional life ahead of you. The main difference is , perhaps , that your greatest temptations in college were those offered by your teachers , who tried to entice you into realms of harder work, closer application , increased concentration , clearer thinking and better understanding , by animating your curiosity and increasing your powers of reasoning and of observation . In other words , here you have carefully and systematically been decoyed toward finer and loftier things . Do not expect that similar helpful influences will greet you on every side in your professional life . Often quite the contrary is the case .

Oct 1, 1930

By D. Harrington

During the 5-year period 1906-10 inclusive, 84 major disasters (a major disaster being one in which 5 or more lives are lost) occurred in the coal mines of the United States, or an average of 17 per year, and the total number of fatalities from coal-mine gas and dust explosions (major plus minor) for the 5 years aggregated 2,338 or 477.6 per year. The monotonous continuance of coal-mine disasters month by month aroused the people of the United States to such an extent that it was felt necessary for the Federal Government to try to do something looking to the avoidance of the admittedly excessive loss of life in our coal mines, and this was one of the deciding factors in the establishment of the United States Bureau of Mires in 1910. That results have been obtained in this particular cause of coal-mine accidents may be seen from the fact that for the year 1933 but one major explosion disaster occurred in the coal mines of then united States and the total number killed in that disaster was 7. Unquestionably the coal-mining industry through use of oaf or mining practices and aided by the various kinds of work of the Bureau of Mines looking to the prevention of mine fires and explosions is in large part responsible for this very creditable change. If the gas and dust explosion fatality rate of 1.059 per million tons of coal produced during the period 1906-10 inclusive had continued to the first of January 1934, instead of the 6,373 deaths which actually occurred due to gas and dust explosions, there would have been 13,480. Hence, during the 23 years existence of the Bureau of Mines there has apparently been a saving of about 7,102 probable deaths, or an average of more than 300 per year, from gas and dust explosions as against the number which would have occurred had the 1.059 gas and dust explosion fatality rate for the period 1906-10 continued. Thirty-nine persons were killed in all kinds of explosions (both major and minor) in the coal mines of the United States in 1933; if the 1.059 gas and dust fatality rate of the 1900-10 period had been in effect in 1933, about 400 persons world have been killed. Unquestionably, the various teachings of the U.S. Bureau of Mines looking to the avoidance of explosions and fires in mines have had a vital influence in reducing the number of explosions and fires and also in decreasing their destruction in case they occur.

Jan 1, 1934

By J. W. Town

The Bureau of Mines determined the physical properties of southeastern Idaho phosphate fines as related to mineral composition, particle size and liberation, beneficiation, and potential use in structural clay products. The phosphate mineral in the fines was identified by unit-cell dimensions to be essentially the same as the phosphate mineral fluorapatite identified in the coarser sizes. The mean particle frequency as determined by electron-microscopy and pipet-analyses was between 0.5 and 0.2 micron. Liberation of the phosphate could not be definitely determined because of the weathered condition of the minerals and their extreme fineness. No beneficiation scheme was developed that would concentrate the phosphate into a marketable fertilizer product; therefore, forming and firing tests were made to demonstrate that the fines can be used to manufacture structural clay products.

Jan 1, 1968

By Raymond B. Ladoo

"The increasing realization of the fire hazards involved in the use of wooden shingles caused the National Lumber Manufacturers' Association to beginsome five years ago a search for a suitable fire-resistant paint. The problem was submitted to the Educational Bureau of the Paint Manufacturers' Association of the United States and work was started by Mr. Henry L. Gardner at the Institute of Industrial Research, Washington D.C. in collaboration with Dr. Herman von Schrenk, a timber expert of St. Louis.The results of this,work have been described by Heckel, in ""Asbestos"", (Heckel G.B., Asbestos in the Paint Industry, Asbestos, Vol. 2, July, 1920,pp.- 5-10).,,who gives the following formula for one of the colors as typical: It will be noted from this formula that ""asbestine"" forms 33% of the total liquid pigment by weight or 31.8% of the solid constituents. Hockel in the article referred to describes this paint,as ""asbestiform"" and assumes since ""asbestine"" is magnesium silicate it must be the chrysetile variety of ""Asbestine"", however, is not asbestos but is a trade name for a fibrous variety of talc mined in the Gouverneur district, St. Lawrence County, New York. This rather natural error persists through the article and credits asbestos with many desirable properties which are characteristics of talc."

Aug 1, 1920

By Perry N. Halstead

This report describes two goniometers that, by simple manipulation, can be used to ascertain the attitude of a joint, vein, or fracture plane observed on the planar projection of a borehole photograph taken with an NX borehole camera of the type developed by the U.S. Army Corps of Engineers. One goniometer was designed to interpret photographs taken in vertical drill holes and the other for photographs taken in inclined drill holes. In practice, several measurements are made on each photograph with the goniometer. These data are then substituted into mathematical equations, which are derived in this report and the attitudes of fracture planes are determined.

Jan 1, 1968

By Paul M. Tyler

This paper presents one of a series of digests of foreign mining legisla- tion and court decisions that 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 Switzerland 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 consuler officers, to whom it is being referred through the courtesy of the Department of State. Sitzerland is a small country in which little mining is done, yet it has a voluminous body of mining legislation. There are two salt-mining districts in Switzerland; that at Bez, Canton of Vaud, belongs to the Canton but the deposit is worked by a private company; and those at Schweizerhalle, Rheinfelden and Ryburg are worked by a joint stock company formed by the Cantons interested. Iron ore is mined at Gonzen, Canton of St. Gallen, and large beds of gypsum are worked, mainly for domestic consumption. In general, however, although many kinds of minerals are said to have been found in Switzerland, mining operations are irreguler end relatively unimportant. Even during the world war only about 2,500 persons were employed in mining establishments and most of these were in under round stone quarries. On the other hand, the republic comprises 22 Cantons, of which 3 are divided, making 25 units, and in the absence of generel Federal legislation, each of these units virtually has its own distinct mining la Under these circumstances, it is obviously inadvisable to review the mining lars of Switzerland in the same detail as those of other countries which Lave been digested in this series. For the lars of individual Cantons, as well as for a more comprehensive summary of the Swiss legislation as a whole, the reader is referred to a recent German publication." Many of the statements in the present paper can be traced to this source. Acknowledgment is also made of the brief analysis published by anot..er German authority..

Jan 1, 1933

By Robert M. Becker

This report (part 3 of a five-part series) presents computer programs for evaluating moments and moment relationships of the generalized probability distributions extended or developed in parts I and 2. The principal program is for evaluating the first three moments and moment relationships of the compound-multinomial distribution for finite as well as for infinite populations. This is the generalized distribution for sampling to some amount of items per sample. Another program is for evaluating the first four moments, the moments of the mean, and the moment relationships of the multinomial and generalized hypergeometric distributions. This is a general moment program in sampling to some number of items per sample or for sampling to some number of samples. This program will accept either ungrouped data, frequency data, or probability data.

Jan 1, 1965

By Dennis R. Dolinar, John L. Ellenberger, Gabriel S. Esterhuizen, Anthony T. Iannacchione

A survey of pillar conditions was carried out at 21 operating limestone mines that use the room-and-pillar method. The surveyed pillars were all located in rock that was classified as “Good” to “Very Good” using the RMR rock mass classification system. The average pillar width was 14.5m and the width to height ratio varied between 0.53 and 3.52. Pillar conditions were rated using a visual rating system that accounts for the effect of geological structures as well as stress related fracturing. Nine cases of pillar instability were recorded. Pillar instabilities were typically limited to individual pillars or small groups of pillars within an otherwise stable layout. Local geological structures such as inclined discontinuities or weak bedding planes contributed to instability in seven of nine cases that were observed. Elevated pillar stresses contributed to instability in the two remaining cases. All the unstable pillars observed had width-to-height ratios of less than 1.5. It is concluded that pillar instability is most likely to be caused by unfavorable geological structures in pillars with width to height ratios of less than 1.5. Stress related instability such as rib spalling becomes more prevalent when the average pillar stress approaches approximately 20 MPa.

By Raymond B. Ladoo

Talc mining ·in the state of New York was first started about 1876, but important production did not start until 1880, when about 4,000 tons were shipped, In 1883 the production was about 6,000 tons valued at $75,000, or an average of $12.50 per ton, From this date the production gradually inc~eased to a peak of 93,236 tons in 1916, valued at $961,510 or about $10,30 per ton, In 1918 the production declined to 71,167 tons valued at $902,100, or about $12,70 per ton. For ma.ey years New York ,-Jas the largest producer in the United states, but in 1917 and 1918 its output was surpassed by Vennont in tonnage thou[;h not in value. In June, 1920, there were three companies producing talc in the Gouverneur district, st. La,1Tence Co'Ul'lty, and one near Natural Bridge.

Oct 1, 1920

By J. G. Eisele

Solvent-extraction characteristics of dodecyl phosphoric acid (DDPA) were investigated to determine its potential as a fractional or selective extract-ant for individual elements in a rare-earth-yttrium mixture. The DDPA is an effective extractant for splitting rare-earth mixtures into light and heavy subgroups. Yttrium normally extracts with the heavy rare-earth elements but may be shifted toward an extraction sequence with the light rare-earth elements by increasing the pH. Elements in the light and heavy ends of the rare-earth series can be separated from middle-group rare-earth elements by using diethylenetriaminepentaacetic acid (DTPA) as an aqueous phase counter-extractant. Hydrogen-ion dependency of the distribution coefficients differs from that reported for similar systems at tracer-level concentration.

Jan 1, 1965

By J. F. Barkley

"In the course of the Government's Fuel Economy Survey of its own power plants, studies and tests have been made of various oil-burning equipments under power-plant boilers. There are now many types of burners being offered in the relatively limited field of power-plant use. The majority of the types used may be grouped into two general classes- those using steam to effect the atomizing of the oil, and those using mechanical means.Burners using steam have had the most prominence in this field for a long period. The mechanical atomizing type of burner successfully applied on shipboard, however, pointed to a possible betterment in land work. The vision presented itself of a burner that would need no steam for atomizing that would permit of air inlets or registers compactly arranged as a part of the entire burner, and that would only require the natural stack draft usually available in land boiler furnaces. Hence, rather recently there has been much development along this line, resulting in various types of burners.In Table 1 are grouped test items chosen from many tests showing representative analyses of the products of combustion obtained with various burners installed in various types of furnaces. In all these tests the burners were handled by experts and represent practically the best attainable for that particular arrangement. The boiler efficiencies ranged from 70% to 80%. It will be noted that the burners using steam for atomizing were able to secure slightly better 002 and less 02 without the presence of CO."

Feb 1, 1926

By G. J. Slavens

The U.S. Bureau of Mines conducted research on preparing submicrometer titanium nitride (TiN) powder as a substitute for tungsten carbide (WC) in cutting tools and wear-resistant parts. Earlier research on a small scale was expanded to include a larger reactor. The TiN powder was produced by contacting titanium tetrachloride (TiCI4) with anhydrous ammonia (NH3) in the presence of Mg at 1,100° C. The powder was collected in an electrostatic precipitator (ESP) filled with ultra-high-purity (UHP) Ar. All collected powder was thermal vacuum distilled to remove Mg and magnesium chloride (MgCl2), leaving the purified TiN. Powder handling and purification procedures were conducted to assure low oxygen content in the powder product. Oxygen content in the distilled TiN powder product was as low as 0.40 wt pct. Nitrogen averaged near 22.0 wt pet with a high of 22.4 wt pct. The purified powder product had an average median particle diameter of 0.14 µm with a standard deviation of 0.09 µm.

Jan 1, 2010

By G. L. Neumann

The Guymard mine in Orange County, N. Y., is reported to have been discovered in 1862 and mined until 1876, producing 10,000 tons of lead and zinc ore. The property was examined by an engineer of the Bureau of Mines in 1948. Development work was done by the Bureau in April and May 1949 and March 1950. During these two periods four drill holes totaling 2,090 feet were completed. The mineralized sections of the core were sampled and assayed.

Jan 1, 1952

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Jan 1, 2008

By William R. Wayment, David E. Nicholson

The Bureau of Mines studied some physical properties of hydraulic backfills and their paramount characteristics , and made preliminary attempts to compact this type of material . The in- place density of hydraulic backfills affects the properties of strength , consolidation , and water percolation . Dense fills give better support than loose fills . In - place density properties themselves are affected by grain size , grain size distribution , and the particular conditions of sedimentation in a stope ( the amount of work the slurry water does to compact the material ) . Field sampling of in - place densities of fills presently used in four different mines and laboratory and underground compaction tests using a standard concrete vibrator show that the initial in - place density of the cohesionless fill material tested can be significantly increased by vibratory compaction .

Jan 1, 1964