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By IRENE AITKENS

The Mining Law of 1910 , with amendments of 1914 and 1928 , is at present in force in the Dominican Republic . The first and basic mining law of the Republic was passed in 1876 , and although numerous changes and amendments have been made from time to time , the new laws and amendments thereto have not changed the original or basic law materially . However , these enactments have materially changed the legal methods governing the exploitation of the mineral resources of this country and have added new regulations and requirements to those concerning certain specific minerals , etc. The original or basic law still exists as it was first promulgated to protect the rights of the Dominican Republic itself , the rights of the landowner , and the rights of prospectors in general . The Mining Law of 1876 remained in force , without amendment , until it was superseded by the law of May 25 , 1904 , an enactment modeled after the Mexican mining law and designed especially to encourage the investment of

May 1, 1931

By Raymond B. Ladoo

The uses for which ground talcs are suited closely depend upon their physical and chemical properties , but , in spite of this fact , little scientific investigation has been made in order to devise quick and accurate tests for the determination of these properties . The chemical properties of talc are inherent and may not be altered or modified except by selective mining or by chemical processes not practical in the present status of the industry . However , the determination of chemical properties is not so important , for most uses , as of physical properties , although sometimes certain chemical characteristics are perhaps unduly insisted upon by chemists in some industries . Physical properties are dependent both upon mineralogical characteristics and upon methods of grinding and sizing and may thus be partly changed or modified by changes in practice . There is so little known of the chemistry and physics of the various processes in which talc is used that the purchase and sale of talc is governed more by rule- of- thumb methods dependent upon individual opinion and often , prejudice , than by accurate , standard tests . This not only causes unwarranted price fluctuations , but injures both the producing and consuming industries by creating false ideas of the suitability of talc for various uses . It thus seems important that present tests be standardized and made uniform for the whole industry , and that new tests devised to fill the existing gaps .

Jul 1, 1920

By K. C. Dean

Changes in the types of materials used for the construction of recent automobile models have occasioned a review of the continued applicability of current recycling techniques. Plastics are being used increasingly in late model cars. To evaluate the changes occurring, a 1972 Mercury Montego, furnished by the Ford Motor Co., was completely dismantled and analyzed, and the composition was compared with that of a composite automobile from 15 vehicles ranging in date of manufacture from 1954 to 1965 and designated as a circa 1960 model. The composite vehicle contained about 26 pounds of plastics, while the 1972 model contained over four times that quantity. The increasing use of plastics in automobiles suggests that research to improve the economic potentiality of plastics recycling is warranted.

Jan 1, 1974

By B. M. O'Harra

The residues resulting from the retort distillation of zinc ores have from 40 to 75 per cent of the weight of the original ore and contain from 5 to 15 per cent zinc . A rough estimate indicates that approximately 450,000 tons of residues are produced annually in the United States , containing about 36,000 tons of zinc . Besides the current production of residues there are at many smelter sites large accumulations from past operations which are available for treatment if this can be done profitably . In addition to their zinc content the residues contain much unconsumed coal , which has been carbonized during the distillation process , and those from most western ores also contain lead and silver . In this paper is summarized the information obtained in a survey , recently made by the Bureau of Mines , in cooperation with the Missouri School of Mines and Metallurgy , of processes which are in use or which have been suggested for the treatment of retort residues . The complete report of the survey is to be published as a Technical Paper of the Bureau of Mines .

Apr 1, 1923

By John J. Sammarco

Illumination plays a critical role in an underground miner?s safety because miners depend most heavily on visual cues to recognize hazards. Mobile mining machinery, located in the miner?s peripheral field-of-view (±10° to about ±60° off-axis), may pose potential pinning and striking hazards. The main objective of this research was to determine if there were peripheral visual performance improvements for the detection of moving objects when using cool-white light-emitting diode (LED) cap lamps as compared to incandescent (INC) light bulbs commonly used in miner cap lamps. The cap lamp variable of interest is the spectral power distribution (SPD); the illuminances were normalized by a diffusion filter. The second objective was to determine if age is a factor for peripheral visual performance. This is important because the workforce is aging ? the average miner age is about 43 years old. Thirty subjects participated in the study; ten subjects each in the age groups of younger (18 to 25 years), middle (40 to 50 years), and older (50+ years). Visual performance was quantified by the subjects? speed and accuracy of response to detect the rotation of high-contrast (white) circular targets located 3.83 meters (m) away at -20°, 40°, and 50° off-axis. The speed of detection and the number of missed target rotations (accuracy) were measured. The prototype LED cap lamp results were best with a 11% to 15% improvement compared to the INC and LED cap lamps respectively. Age does appear to be a significant factor. For the middle and older age groups?, target movement detection time increased 75% and 60% and the number of missed targets increased 500% and 450% respectively in comparison to the youngest age group. The results also suggest that target location is a significant factor. The subjects? target movement detection time for the 40° and 50° target movements increased 16% and 69% respectively as compared to the -20° target.

Jan 1, 2008

By E. J. HOFFMAN, J. c. W. FRAZER

The apparatus and methods described in the following pages were devised and used by the writers in connection with certain investiga- tions of the technologic branch of the United States Geological Sur- vey, especially those bearing on the improvement of furnace condi- tions and on efficiency in the use of fuel. The Bureau of Mines, which has charge of such analyses and tests of fuels as were formerly made by the technologic branch of the Sur- vey, is using the same apparatus and methods in connection with similar investigations that are being carried on at the testing plant of the bureau at Pittsburg, Pa. The furnace conditions prevailing both in small plants and in large industrial establishments in this country are frequently far from satisfactory. If such conditions are to be improved, they must be more thoroughly understood, and means must be found to insure complete combustion of the fuel, and yet to permit operation with such an excess of air as will result in the greatest efficiency. In this work the services of the chemist are indispensable. A very important problem is the determination of the small percentage of unburned combustible matter that escapes from the furnace in the flue gases. Under ordinary circumstances so little as 0.1 per cent of unburned combustible matter in a furnace gas is equivalent to about 1 per cent of the fuel used; and for the determination of such small percentages of gas more accurate and refined methods are required than have ordinarily been available heretofore. It is the purpose of this paper to describe some apparatus and methods which have proved satisfactory to those engaged in the chemical work of the investigations mentioned. While these methods and apparatus have been designed more particularly with regard to analysis of furnace gases, their use is by no means limited to that purpose. The reader will readily see their applicability to other uses in which the sampling and analysis of gases are involved.

Jan 1, 1911

By R. Hogg

"The problems of sampling particulate materials, and of characterizing the distributions of particle size and composition are reviewed. Requirements for sampling from comminution systems are discussed and a simple formula is presented for estimating the minimum sample size needed. The limitations and errors associated with the techniques available for particle size analysis are evaluated and guidelines are suggested for the selection of appropriate methods. The use of microscopic and macroscopic approaches to the characterization of particle composition are discussed.INTRODUCTIONComminution is a process of particle size reduction in which the goal is to produce a material with a specified particle size distribution from a coarser feed. In mineral processing applications, the product size distribution is often qf secondary importance to the extent to which individual mineral grams can be liberated from one another. However, due to poor understanding of the nature of the liberation process and the lack of reliable procedures for characterizing it, the actual specification is normally in terms of particle size.Particle size distribution can be regarded as the fundamental characteristic of a particulate system. The distributions of particle shape and composition among the various particle sizes present are often sufficient to define the bulk properties and behavior of the system. Description of the distributions of size; shape and composition of the different phases which may exist within individual particles is necessary to complete the picture and is especially important for predicting liberation etc., in comminution processes. It is quite obvious that · the complete characterization of real particulate systems is a formidable, if not .impossible task. Practical characterization procedures should involve ·evaluation of those characteristics which are deemed to be important and which can be measured. In comminution systems, this should ideally include the particle size distribution, the size-by-size distributions of particle composition, and as much information as can be acquired on the internal composition and structure of individual particles. In most cases, of course, we fall far short of even this rather limited goal."

Jan 1, 1988

Case studies from four western states are used to illustrate the impact of the environmental compliance process on the mining industry. The case studies were not chosen as a statistically significant sample of all mining operations in the western United States but were chosen as representative of operations on both public and private lands and in locations that exhibited varying degrees of involvement by governmental units, non-governmental organizations and the general public. Basically, each case study was chosen because some aspect of their environmental compliance process helped to illustrate an interesting point in the regulatory process. The criteria used to select the case studies were: mines located in different jurisdictional areas, mines located in varying geological areas~ mines located in areas having different historical relationships with mining: and operations that are in production as well as those seeking an operating permit. The variety of such projects should provide the necessary foundation to evaluate the impacts of the environmental compliance process in each location.

Jan 1, 1994

In this U.S. Bureau of Mines report, in situ vat leach mineral recovery system concepts are described and cost compared with conventional mining and pad and autoclave leach processing systems. In the proposed systems, leachable ores are enclosed in place in reagent-impermeable in situ vat constructions. The ores are then rubbled and flood leached or flood oxidized and leached. The in situ vats are called stope leach or stope autoclave vessels. The report also proposes ore body-adjacent in situ vat constructions containing rechargeable processing stopes. A series of ore body-specific, innovative, and conventional mineral recovery systems case study designs are described and prefeasibility level costed. Based on a comparison of these prefeasibility level cost estimates, the proposed systems are determined to be economically competitive with conventional min¬eral recovery systems. The in situ vat leach mineral recovery systems concepts for leachable and refractory ores are developed around the drill-split narrow-vein and longwall mining methods described in part 1 of this Information Circular series.

Jan 1, 1995

By James H. Russell

The Bureau of Mines used a statistical approach to evaluate the effects of temperature, current density, and composition of the electrolyte on the purity of boron prepared by electrolysis of a fused mixture of boric oxide in potassium fluoborate. The quadratic equation which best fits the data was calculated for a temperature of 650° to 850° C, a cathode current density of 40 to 1,150 amp/ft2,and a boric oxide content of 0.3 to 7.1 molal. The best products, better than 95 percent boron, were obtained when the current density was less than 2 amp/ft2 and the boric oxide content was less than 2 molal.

Jan 1, 1967

By W. M. Deaton

[Knowledge of the ten?erat~rre to wkich n gas ullder3atur~ted xith re- srplc t to water vapor may be cooled before the water p?f 11 3egin to condense 8 is desirable .and frec-uently iq neceTsarp in nWy resenrch c~d industri~J activities. This tenperrture, the dew point, i s 2 nrrticulnrly innortmt factor in high-pressure gas transmission, PS water cox?-ensate any interfere i with the flow of gos in the line. Sonetimes this interfexnce is due only to the yresence of the liquid water. At other tfncs, under certain condi- tions of pressure and teriperature, the cogdense;? water cn!nhines with the 93 to farm solid .y2: hydrctes. These solid coar~ouncis ma:/ ccllect in sufficient quantit;. to rehce materially the c~xrying cap.citg of the pipe line or ever, to ply thc line coimletelp. ]

Jan 1, 1938

By W. M. Deaton

[Knowledge of the ten?erat~rre to wkich n gas ullder3atur~ted xith re- srplc t to water vapor may be cooled before the water p?f 11 3egin to condense 8 is desirable .and frec-uently iq neceTsarp in nWy resenrch md industri~J activities. This tenperrture, the dew point, i s 2 nrrticulnrly innortmt factor in high-pressure gas transmission, PS water cox?-ensate any interfere i with the flow of gos in the line. Sonetimes this interfexnce is due only to the yresence of the liquid water. At other tfncs, under certain condi- tions of pressure and teriperature, the cogdense;? water cn!nhines with the 93 to farm solid .y2: hydrctes. These solid coar~ouncis ma:/ ccllect in sufficient quantit;. to rehce materially the c~xrying cap.citg of the pipe line or ever, to ply thc line coimletelp.]

Jan 1, 1938

By Harold J. Barnett

In January 1948 , the Secretary of the Interior directed that a study be made of energy resources and requirements that would provide a basis for continuing appraisal of the adequacy of the Department's programs in the energy field . That this instruction was timely has been demonstrated by the increasing interest being evidenced by Congress , industry , labor , and the public in the future of the energy segment of our national economy . Several studies of individual energy sectors have appeared . Various legislative proposals have been made in Congress for obtaining more information on this subject . Substantial interest in energy projections is not , of course , a recent innovation . Energy availability and consumption are strategic factors in peacetime prosperity and growth and in our national defense as well . The past generation's literature of earnest public discussion and of legislative consideration of matters involving energy projections is very extensive . This is an exploratory study produced in the Program Staff of the Office of the Secretary of the Interior in the first half of 1949 and revised recently to take account of certain of the preliminary energy data from the 1947 Census of Manufactures and critical comments . It is offered at this time solely as a technical contribution in economic research technique . As the Bureau of Mines has recently undertaken to revise this preliminary study , critical and other comments are invited .

Oct 1, 1950

According to industry representatives, U.S. producers were listing unalloyed 95.5 percent aluminum ingot in October at 53-57.5 cents per pound, but reportedly much is being priced at 53 cents. New York dealers raised their October positions by about 3 cents to 56-56.5 cents, mainly to cover spot supply shortages. London Metal Exchange 3-month forward contracts traded up in October from 52.3 to 57.3 cents per pound and closed at 56.4 cents. ASBESTOS The Jaquays Asbestos Corp. has announced the imminent closure of its mine and mill in Globe, Arizona. This is the last asbestos producer in the State having operated continuously, except during the early thirties, since 1914. Cost of compliance with environmental regulations was given as the reason for closure.

Jan 1, 1978

By Thomas A. Jones

An impure variety of barite, which lends itself well to the manufacture of heavy drilling mud for oil wells, is widely distributed throughout the Ouachita Mountains in Arkansas. The ore mined in the area and used for drilling muds usually contains an average of 67 percent barium sulfate, although ores as low as 50 percent BaSO4 are occasionally used. Due to the increased demand for barite for drilling caused by the intense search for hew oil occurrences during the years 1945 and 1946, the Federal Bureau of Mines began an investigation of barite deposits in the Ouachita? Mountains in October 1946. In all, 10 barite deposits were examined, trenched, sampled, and studied during the investigation, which was terminated in May 1947.

Jan 1, 1948

By Rustu S. Kalyoncu

A major goal of the Bureau of Mines is to conserve the Nation's mineral resources by developing improved performance materials. In support of this mission, a survey of the state of the art of chemically bonded refractories has been made, covering the scientific literature, government reports, and patents. This review includes research and development results for phosphate, silicate, oxychloride, oxysulfate, and other bonding agents used in refractories manufacture. A significant finding of the review was that references on bonding mechanisms, bond formation kinetics, and other important process parameters and conditions were few and universally vague. As a result, recommendations are made to expand research efforts to investigate the kinetics and mechanisms of reactions in chemically bonded refractories.

Jan 1, 1982

By Manuel Gomez

A computerized moving average technique was developed to interpolate coal seam characteristics between sample points. The interpolative method coupled with multivariate regression analysis and simulation procedures was used to forecast coal properties not readily obtained from an analysis of drill core samples. Coal property forecasts were of two kinds: (1) specific mine property forecasts that are suitable for mine product control and yield a good approximation of the local variation along both the vertical and horizontal axes of the seam, and (2) regional estimates where much of the local seam variation is smoothed out, but the general trends are maintained. Forecasts of the volatile matter, ash, total sulfur, and the heating value for part of the Pittsburgh seam located in Ohio, Pennsylvania, and West Virginia were in good agreement with independent evaluation data. Spatial configuration for preparation characteristics, particularly, the effect of crushing on sulfur release, low-and high-temperature carbonization properties, the Hardgrove grindability index, the coal hardness index, gasification variables, and hydrogenation factors were constructed for the same area of the Pittsburgh seam. These forecasts may be developed from drill core data collected in the exploration phase of mining. The results, which may take the form of a series of maps, are useful to mining, chemical, and combustion engineers, to economists and mine managers, as well as to coal users for mine design, economic analyses, energy forecasts, utilization studies, mine product control, and environmental control and programming.

Jan 1, 1974

By L. A. Neumeier

The Bureau of Mines evaluated the properties and anisotropy in properties of rolled Zn-Cu and Zn-0.12 pct Ti-Cu alloys with various copper additions to 1.25 pct. The alloys were rolled cold and at various hot-rolling temperatures to reductions as high as 92 pct after breakdown rolling. The properties are extremely sensitive to various combinations of composition, rolling temperature, and rolling reduction, Zn-Cu alloys can develop good creep resistance, but they are inferior in that respect to Zn-Ti-Cu alloys. For alloys either with or without the titanium addition, cold-rolling results in recrystallization of the matrix and rejection of copper from solution, causing poor hardness, tensile, and creep properties, but high ductility. Peak tensile strengths develop when the alloys are rolled in the range 320° to 400° F, Best creep resistance for Zn-Cu alloys requires higher rolling temperatures when copper content is increased. Creep resistance is best for Zn-Ti-Cu alloys with about 0.75 to 1.0 pct CU rolled near 480° F. Some copper is soluble in the TiZn15 phase, which forms into "stringers" during rolling. The possible contributions to creep behavior of factors such as distribution of second-phase particles, grain size, and preferred orientation are discussed.

Jan 1, 1970

By Donald E. Redmon

This Bureau of Mines report reviews injury experience in the nonmetallic mineral industries (except stone and coal) for 1968-69. For each of the years, 23 tables summarize disabling work injuries by department, source of injury, extent of disability, part of body injured, and nature of injury. Correlative information on employment, worktime, and operating activity is also presented.

Jan 1, 1973

By M. S. Oudenhoven

The Bureau of Mines conducted an investigation to determine the theoretical stress distribution in the vicinity of explosively expanded rock bolt anchors independent of their bolts. Plane-strain solutions applicable to this problem were obtained by combining the field pressure with the uniform pressure that would be produced by vertically placed anchors having 2-, 3-, and 4-foot spacings. High rock stress which would be produced by an anchor was localized, as would be expected from St. Venant's effect, and increased as the field pressure decreased.

Jan 1, 1967