Search Documents

By S. S. Peng

Successful longwall mining requires a good roof control. A good roof control implies that: (1) no excessive pressure is build up in the face powered supports, and (2) chain pillars are designed in such a way that panel entries are well protected and interactions between adjacent panels are minimized. A clear understanding of strata behavior around longwall panels due to face movement is, therefore, the foremost requirement for achieving better roof control. This dissertation is designed to analyze the effects of strata behavior on longwall panels due to the mining activities. The following topics are studied: (1) the weighting, phenomena and their effects on front abutments, and (2) the chain pillar stability and pillar design under various roof conditions. Three dimensional finite element analysis was employed. The effect of parameters such as overburden depth, mechanical properties of the immediate roof and main roof, panel width, and size of chain pillar on (t) and (2) were analyzed. Four typical models were utilized to simulate various phases of panel extraction under various combinations of the above parameters; model one is to simulate the beginning of panel mining; model two is to simulate the situation that longwall face has passed more than half of panel length; model three is to simulate the completion of panel production; and model four is to simulate the second panel mining. The following formulae have been developed by applying multiple regression model to analyze the finite clement results: (1) a formula that classifies the type of root strata at the face area. (2) formulae that predict the first weighting and periodic weighting lengths. (3) a formula for design of the chain pillar size. Case studies were performed to check the validity of the formulae proposed. Comparison of the formulae proposed for the chain pillar design with other formulae were also performed.

Jan 1, 1984

By James R. Boyle

The value of Alabama's nonfuel mineral production in 1987 was $446.6 million, an increase over that of 1986 and the first increase in 3 years. Alabama was second in the Nation in production of bauxite and ferroalloys; third in bentonite, crushed dolomite, crushed marble, and fire clay; and fourth in masonry cement. Trends and Developments.-Employment in the minerals industry remained relatively low for the second year even though the overall unemployment rate dropped to 7.9% by December. Employment in mining and primary metals dropped about 10% and 2%, respectively.

Jan 1, 1989

By W. E. Brown, P. R. Porath, V. Miller, C. E. Wood, C. Prasky, E. P. Barrett

"INTRODUCTION This investigation was a part at the Bureau of Mines program for the production of critical and essential materials needed for the war.The Boykin Committee for investigating the steel shortage aided in obtaining an appropriation to be expended by the Bureau of Mines in studying the utilization of North Dakota lignite in the manufacture of hydrogen that could be used in the production of sponge iron from low grade ores of Minnesota.OBJECT OF INVESTIGATIONThe investigation was conducted by the Bureau of Mines to ""determine the workability of the proposed bubble-hearth process and its possible use in connection with an experimental plant for the gasification of lignite being operated by the Coal Division of the Bureau of Mines at Grand Forks, North Dakota.ACKNOWLEDGMENTSThis report is one of many on various aspects of the Bureau of Mines program directed toward the more effective utilization of our mineral resources.Investigations of our mineral resources are conducted by the Mining Branch, L. B. Moon, chief, and by the Metallurgical Branch, O. C. Ralston, chief.The scope of the report falls in the province of the Metallurgical Branch, whose activities embrace the separation of difficulty beneficiated ores, the production of pure metals from domestic deposits, the exploration of marginal ore reserves, the recovery of secondary metals, and the improvement of present industrial metallurgical practice."

Jun 1, 1947

By S. M. Dar

The U.S. Bureau of Mines constructed a full-scale model of a 15-ft-wide coal mine entry to use in combination with finite-element analyses to investigate roof support systems and various types of roof bolts. The objective was to enhance understanding of the fundamental mechanics of the interaction between rock and supports and the relative integrity of bolted mine roof as a function of roof bolt type, length, spacing, and tension, and the basic characteristics of the roof strata. The laboratory test results, when correlated with computer simulations using fmite-element analysis and underground verification tests, should provide a basis for desigillng safer, more cost-effective roof control systems and help to establish guidelines for employing fully grouted resin and mechanically anchored bolting systems. The background for this research, the research approach, the methods and equipment employed, and the results are described in this report.

Jan 1, 1989

By J. L. Konchesky

The technical feasibility of gasifying powdered, noncoking, low-rank coal with steam in an externally heated tube has been demonstrated. The tube, 112 ft. of alloy-steel tubing shaped into a helix, served as an electrical conductor of electricity used for heating. The effects of the following variables were studied: Residence time of coal in reactor, average reaction temperature, steam concentration, and rank or geologic age of coal. Reaction pressure was maintained in the range 19-26 p.s.i.a. High carbon conversions and large yields of synthesis gas were obtained with low-rank coal. In one test, for example, about 88 pct. of the carbon in a subbituminous C coal was gasified at 1,910* F. with a residence time of 1 sec. The gas contained 58 pct. H2, 19 COD 15 CO, and 3 CH4; the yield was 30 cu. ft. (at 32' F. and 14.7 p.s.i.) of synthesis gas (CO + H2) per pound of dry coal.

Jan 1, 1960

By Joseph B. Cummings

"Occurrences of fluorite on the Packard property were first examined by an engineer3/ of the Bureau of Mines in July 1943 as the result of receipt of an application for an access road. In August of the same year the showings were examined by a geologist4/ of the Federal Geological Survey. The property was again examined by an engineer5/ of the Bureau of Mines in March 1944. This last examination resulted in a proposal that access be gained by construction of a truck trail and that the Bureau of Mines undertake to explore the fluorite showings.The truck trail was constructed by the Public Roads Administration, which began the work on February 17, 1945, and completed it 8 days later.The Bureau of Mines exploratory program was completed on May 16, 1945. It consisted of stripping overburden, trenching, test pitting, tunneling, sampling, and topographic mapping.In addition to being described in some detail, the extent of the work as well as results are shown in accompanying tables and figures.Mrs. Rhoda A. Packard, Mrs. Nora 1. Cline, and C. B. Pettingill, all of Tonto Basin, Ariz., own the property, which comprises four contiguous, unpatented lode mining claims recorded at Globe, Ariz., as the Walnut and the Bluebird 2, 3, and 4. The claims are situated in T. 6 N., R. 11 E., Gila County. David L. Roscoe of Tombstone, Ariz., holds a lease and option to purchase.Access to the property is by Highway 88 from Globe, 34 miles to Roosevelt, thence 24 miles by a graded county road along the west side of Roosevelt Lake to Tonto Basin. Here the Greenback Ranch road, constructed by the Forest Service and maintained by the county, crosses Tonto Creek and continues easterly to the foothills. The truck trail leaves the road 8.5 miles east of Tonto Basin and runs 2.5 miles in a southerly direction to the property. (Fig. 1.)The fluorite deposits lie in and along a small canyon in a rough, rocky area at an altitude of about 3,400 feet, Vegetation is scant and of the usual desert variety. The summer climate is dry and hot and the winter climate moderate. Rainfall at the Forest Service Station in Tonto Basin was 11.4 inches from May 1944 through March 1945."

May 1, 1946

By Floyd R. Hertweck

This Bureau of Mines publication contains analyses and related source data for 349 natural gas samples from 26 States and 2 foreign countries. The 3 samples from foreign countries and 339 of the U.S. samples were collected during calendar year 1983. The remaining seven samples were collected earlier, but releases granting permission to publish were not received until 1983. All samples were obtained and analyzed as part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by the mass spectrometer and chromatograph. The results of these investigations are published annually to make the information available to the petroleum industry and the general public. Twenty-seven publications have presented the results of 13,332 gas analyses made prior to 1983. The first three bulletins (1-3)3 contain analyses and related source data on 5,218 gas samples collected from 1917 through 1960; these bulletins have been supplemented annually by information circulars (4-17, 19-24, 26-27) containing 8,104 analyses of sam¬ples collected since 1960.

Jan 1, 1984

By G. L. Neumann

Owing to the need for additional sources of supply of both zinc and lead following World War II, the Bureau of Mines investigated many abandoned lead-zinc mines in the eastern United States. A series of shallow veins in south-western St. Lawrence County has long been a subject of speculation. These veins, which average about 4 feet in width and cut across the bedding of the country rock at right angles, are filled with calcite-carrying galena and sphalerite. The deposits have been worked sporadically during the last 115 years. From 1837 to 1852 the Coal Hill, the North, and the Victoria mines near the village of Rossie were at their peak of activity. Other calcite veins were prospected and a small production was realized. The Bureau of Mines began diamond drilling May 1, 1950, under the general supervision of McHenry Mosier, chief, Mining Branch, Bureau of Mines, Region VIII, and under the immediate supervision of the author) who was project engineer, following the preliminary examination by Robert S. Sanford. A total of 3,870.2 feet was drilled in 18 holes on four of the numerous deposits scattered over Macomb and Rossie townships. Drilling was completed September 21, 1950.

Jan 1, 1952

By Pamela J. Watson

The U.S. Bureau of Mines has demonstrated in laboratory tests that drilling with surface-charge-neutralizing concentrations of polyethylene oxide (PEO) polymer solutions simultaneously improves penetration rates and extends bit life. The applicability of this additive to improve drilling performance in coal measure rocks was demonstrated under field conditions at an abandoned mine land site in Pennsylvania and a producing coal mine property in Ohio. Penetration rate improvements ranging from 15 to 50 pet were obtained when core drilling through a variety of coal measure lithologies. Drilling cost analysis indicates that the small added cost of using the polymer is more than offset by the savings that result from demonstrated increased drilling penetration rates, which translate into drilling cost savings of about 10 to 30 pct. This report also gives chemical analyses of a variety of coal measure rocks and some corresponding local drilling water samples, obtained from a wide geographical base, along with threshold concentrations of PEO required to effect the improved drilling performance in these rocks. From these data, the threshold PEO concentrations needed to ensure improved drilling performance can be estimated for any coal measure rock suite. Proper techniques for mixing PEO solutions are also presented.

Jan 1, 2010

By N. P. Kripakov

The Bureau of Mines has developed a unique new mine design procedure to determine the changing static load distributions imposed on under-ground support structures during the mining cycle. The procedure reduces the complexities associated with analyzing a three-dimensional problem. A combination of the multiple-seam displacement-discontinuity model and a two-dimensional finite-element window model produces refined results for a specific area of interest by assuming displacement compat-ibility between models. Input to the procedure includes the geometry of mined-out areas in up to two adjacent seams, the rock mass characteris-tics of the surrounding geology, the in situ stress conditions, and the mining sequence. The displacement-discontinuity program calculates ex-pected loadings for mine structures affected by the mining cycle and/or by overlying or underlying seams. Pseudoelastic finite-element analysis using a yield-factor approach determines the stability of coal pillars by simulating the degree and extent of nrogressive rib failure and sub-sequent load transfer. Application of the procedure is demonstrated on a field problem. In-duced stress changes predicted from the numerical model analysis are in reasonably good agreement with stress measurements obtained from an instrumented chain pillar affected by remnant workings in an upper seam.

Jan 1, 1988

By Warren E. Morrison

This study was prepared in response to the need for a series of data that reflect the basic flow pattern of energy resources in the United States. To effectively measure and analyze energy,2 it is necessary to prepare balances that reflect both production and consumption, and the various forms energy resources take at different stages of utilization. Before energy can be measured it must also be put into a common unit. In this study the common unit us d is the British Thermal Unit (Btu). The ideal point to survey energy is at the stage of final ultimate use, representing the useful work derived from the interaction of energy inputs and the prime mover. Unfortunately this concept of efficient or useful work from energy output cannot readily be measured in the aggregate. With the present available official data, energy measurement can be carried to the point of calculation of net inputs of energy3 into the economy at various stages of utilization. However, preparation of energy balances, on a net basis is hampered by the fact that this can only be done for years when the censuses of Mineral Industries and Manufactures are taken, usually at 5-year intervals.

Jan 1, 1964

By A. E. Petersen

To reduce U.S. dependence on imports of titanium, the U.S. Bureau of Mines has investigated the recovery of titanium from perovskite (CaTi03). Domestic perovskite deposits represent a significant, but untapped, titanium resource. An acid sulfation method was developed that will extract about 97 pct of the titanium and the columbium and 70 to 90 pct of the rare-earth byproducts from perovskite concentrates. A flow-sheet for recovering titanium as pigment-grade titanium dioxide (Ti02) is discussed. Test work performed in developing each unit operation is described. The first three unit operations have been demonstrated using laboratory-scale continuous methods of operation: acid sulfation of perovskite concentrates, leaching sulfation residue to dissolve metal values, and precipitation of titanium oxysulfate monohydrate (TiOS04?HP) from the resulting leach flltrate. Batch testing of other unit operations was performed: TiOS04?H20 redissolution and iron reduction, precipitation of Ti02 by hydrolysis, and regenerating recoverable acid with rare-earth byproduct recovery. Cost evaluation results are provided, indicating that processing perovskite concentrates by acid sulfation may be an economically viable means of producing Ti02.

Jan 1, 2010

By D. A. Buckingham

The Bureau of Mines evaluated potential availability of domestic nickel from 23 deposits, Evaluations included an estimation of in situ and recoverable resources, applicable mining and processing technologies, and capital and operating costs. Discounted cash flow analysis with a 15-pct rate of return was used to determine the average total cost of production of each operation, Identified in situ resources contain 9.0 million metric tons (t) of nickel; 5.5 million t is recoverable as nickel metal or ferronickel. Demonstrated in situ resources contain 8.2 million t of nickel; 4.8 million t is recoverable as nickel metal or ferronickel. No nickel is available at a total cost of production equal to the January 1983 market price of $3.24 per pound. Analyses indicate that potential annual production can only meet current consumption levels at a total cost of production of $7.60 per pound of nickel, Nickel's availability is contingent on (1) successful adaptability of nickel processing methods to domestic resources, (2) location of a smelting facility, and (3) marketability of byproducts and coproducts. Analyses were performed on the effects of byproduct and coproduct revenues, energy, labor, and transportation costs, and metallurgical recoveries on nickel's availability.

Jan 1, 1984

By D. E. Sullivan

The Bureau of Mines investigated the availability of potash from 68 mines and deposits in 12 market economy countries (MEC's) containing, at the demonstrated resource level, approximately 11.7 billion metric tons (mt) of potash in assay terms of contained K2O; K2O as used by industry as a standard of comparison for the different forms of potash. These resources include almost 190 million mt in the United States, 9.63 billion mt in Canada, approximately 430 million mt in Western Europe (France, Federal Republic of Germany, Italy, Spain, and the United Kingdom), 1.24 billion mt in the Middle East (Israel and Jordan) and over 220 million mt in other countries (Brazil, Chile, and the Congo). This analysis his determined that future production of potash in MEC?s will most likely continue to be from the large resources associated with producing operations in Canada. Based solely on the demonstrated resources included in this study, potash mining in the United States would decline while overseas production from MEC's can continue into the next century at near current production levels. However, timely development of new or inferred resources would offset any such decline. Producing mines in Canada have the resources to increase and maintain increased production well into the next century. For U.S. potash users, Canada is a long-term stable and secure source.

Jan 1, 1986

By F. W. Lee

The paramount importance of water to life of all forms on the earth is too well known to require elaboration in this brief paper. It has repeatedly been termed the most valuable of all our mineral resources. Its importance is justifiably recognized in the extensive areas covering the earth which receive sufficient rainfall to sustain a relatively luxuriant vegetation; but in those areas where rainfall is insufficient to support anything but a relatively meager plant growth, the location of a water supply and its development become of even more vital interest to those attempting to obtain a living from the soil. Geological investigations concerning the water supply of the United States have been most extensive, important work having been accomplished by Federal, State, and local governments and by private enterprise. A casual examination of the titles of the 739 Water-Supply Papers published by the United States Geological Survey3/ alone testifies 'to the vital nature of our water resources and the extensive work that has been done on them.

Jan 1, 1936

By W. P. DYKEMA

This report gins the results of a study conducted hy the Ilnreau of Mines for the purpose of informing the petroleum industry on the recent progress in the de,·elopment nncl application of the absorption process for recO\·ering gasoline from natural gas. The work has been undertaken entirely with regard to plant practice and for the purpose of describing the features and the operation of units of the plants now in use, the improvements that have been made, and the reasons for any ehanges eontemplated by the engineers in eharge· of the plants studied. Throughout the United States the impro,·ements in the absorption process that are under consideration by engineers not only widen practice so as to include gases at all pressures and percentages of gasoline content, but seem to be dewloping definite standards as to dimensions of towers, l"elocities of flow, saturation of oi~ areas of eooling surfaces, and quantities of menstruum to be circulated. Although perfect practice has by no means been attained, the writer belie,·es thnt a description of the current practice at ,·arious plants, including those ob,'iously more efficient features that each plant hns <le\"eloped and uses at one or another stage of treatment, will intere;; t and possibly help all persons operating or designing absorption plants.

Jan 1, 1919

By Charles L. Kimbell

In overall aggregate, the world&apos;s mineral industry in 1987 experienced a more satisfactory year than in 1986, at least insofar as its performance could be assessed from traditional statistical indicators. Production, trade and consumption seemingly advanced in the case of the majority of commodities, and prices for a number of commodities advanced. It was by no means certain, however, whether 1987 investment in mineral industry ventures would top the levels of 1986, when, in the case of petroleum industry investment expenditures there had been a sharp decline, this in contrast to evidences of a slight upturn in steel industry investment. World crude mineral output value was estimated at more than $1,084 billion, and the value added by minerals industry processing of this material probably raised the total value of the industry&apos;s production from primary materials to more than $2,600 billion constant 1983 dollars. Less easy too assess was the value of mineral commodities moving in international trade, but with a resurgence in oil prices from the 1986 levels, an increase above the 1986 $500 billion mark seemed assured. There are no comprehensive aggregate statistics on mineral consumption comparable to those on production and trade, but quantitative growth recorded for most major commodities suggested a favorable trend, particularly when coupled with a general (though by no means universal) upturn in unit prices.

Jan 1, 1989

By W. J. Wiehagen

The Work Crew Performance Model (WCPM) seeks to define performance variability within similar tasks of an underground work crew and relate observed variability to a cost consequence. Performance variability is described using work site observations to determine the adherence to job elements con¬tained within a standard operating procedure. Key components of the WCPM include (1) job definition through task analyses and the ranking of job elements by perceived cost consequence, (2) observational techniques for establishing performance baselines by measuring adherence to safe and proficient job procedures, and (3) cost linkages between adherence to task procedures and measures of consequence for noncompliance. Data presented within this report were obtained through the study of shuttle car operation in an underground mine in Appalachia. Observed adherence to safe and proficient job procedures by opera¬tors matched well with the consensus profiles (measured through a nominal group technique) with min¬ing personnel. It was also found that experienced operators consistently outperformed less experienced, incidental operators. These findings imply potential use of the WCPM as a practical procedure for thinking systematically about the choices available to reduce performance variability. Field application of the model can offer useful data to evaluate training and financially support performance improvement strategies that can be tested for their ability to reduce human error.

Jan 1, 1994

By Philip C. Tully

[This bibliography contains 3,655 different citations to technical and scienfic literature on helium and alpha-particles, abstracted by 13 abstract service iblicatlons during 1964. Multiple subject classification increases the total number of entries to more than 5,800. Helium citations are listed by 22 major assifications, alpha-particles by 12]

Jan 1, 1970

By Shiro Watanabe

To determine the potentialities of nickel as a substitute for cobalt in catalysts for the synthesis of hydrocarbons from carbon monoxide and hydrogen, RESULTS The maximum oil yields obtained in bench-scale equipment were as follows: Using 100N1:20Mn:100 kaolin:200 diatomaceous earth catalyst, a maximum yield of 133.8 cm.3/m.3 of pure CO+2H2 was obtained from one pass of the feed gas, With a nickel:cobalt mixed catalyst (Ni:Co - 3:7) having the composition 100(Ni+Co):8MgO: 5Th02:200 diatomaceous earth, a maximum of 172.2 cm.3/m.3 of pure C0+2H2 was obtained.

Jan 1, 1951