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By Charles Will Wright

The purpose of this paper is to present briefly certain preliminary results of the study of mining methods by the United States Bureau of Mines; to show the relative importance of each method in terms of tonnages mined and man-hours consumed; to give to the mining engineers and particularly to the young student of mining a better understanding of the principal mining methods; and to indicate changes now in progress and to present suggestions for improvements in the art of mining. Questions of mine development and details of underground practice such as drilling and blasting, loading, hauling, hoisting, ventilating, pay systems and mine management are omitted, as these have been or will be discussed in other bureau publications.

Jan 1, 1931

Argentina follows Venezuela and Mexico as the largest producers of crude petroleum and natural gas in Latin America. Argentina 1S practically self-sufficient in fuels, but relies substantially on imports for its supply of copper, iron ore, ferroalloys, sulfur, and fertilizers. Mining activity is limited and is in an incipient stage of growth, considering the country's potential for mining. Most nonfuel mineral output in 1979 consisted primarily of minerals used for construction, while only 9% are other nonmetallic, and 2% are metallic minerals. Argentina is Latin America's major producer of boron minerals and uranium (yellow cake). Mineral exports consist primarily of borates, uranium concentrates, and of late, some tin. These exports have in the past been shipped mostly to Great Britain. London banks have been involved in arranging financing for St. Joe Minerals Corp. IS planned development of the El Pachon copper deposit (see map), and were being counted upon to also back the development of large copper and manganese projects. The following is a review of Argentine mineral production in 1979: (For 1981, the production of boron minerals is put at 167,000 metric tons and uranium at 300,000 metric tons.)

Jan 1, 1982

By Omotayo Kalejaiye

The Siwek 20-L chamber is widely used throughout the world to evaluate the explosibility of dusts. This research evaluated the quality of dust dispersion in the Siwek 20-L chamber using Pittsburgh coal, Gilsonite, and purple K dusts. A Pittsburgh Research Laboratory (PRL) optical dust probe was used to measure optical transmittance through the dust cloud at various locations within the chamber. A total of 540 tests were performed, with triplicate tests at five nominal dust concentrations and six locations. The two standard dispersion nozzles (rebound and perforated annular nozzle) were compared. The transmissions corresponding to the normal ignition delay period were used to: (a) determine variations in spatial uniformity of dispersion obtained with both nozzles; (b) make comparisons between the experimental transmission data and those calculated from theory for the three dusts; and (c) make comparisons with transmission data measured in the PRL 20-L and Fike 1-m3 dust explosion chambers. The uniformity of dispersion for the three dusts was similar with both nozzles, despite the differences in nozzle geometry and mode of operation. Transmission data of the three dusts were all significantly lower than those calculated from theory. This was discovered to be, in part, due to significant reduction in particle size that occurred during dispersion. By measuring particle sizes before and after dispersion, values of 60%, 50%, and 20% reduction in particle size (based on the surface-weighted mean diameter) were obtained for Pittsburgh coal, Gilsonite, and purple K, respectively. Transmission data from the PRL 20-L, Fike 1-m3 and the Siwek 20-L chambers indicated comparable results in terms of uniformity of dispersion. However, transmission data from the Siwek 20-L chamber were significantly lower than those of the PRL and Fike chambers. Again, this was attributed, in part, to the significant reduction in particle size that occurred during dispersion in the Siwek chamber. The design of the outlet (dispersion) valve of the Siwek 20-L apparatus charge vessel was largely responsible for the particle break-up. The contribution to particle break-up by the dispersion nozzles and the high level of turbulence in the chamber were found to be minimal. This is a significant finding in that the dust particle size tested for explosibility in the Siwek chamber is considerably smaller than the original dust sample.

Jan 1, 2010

By R. R. Lowery

An analysis of three 1-1/4-diam manufactured wire ropes of 6x19 classification was done to identify and describe reference conditions of new rope. Reference condition is of value when examining tested or retired ropes. Measurements of strand and rope pitch and of wire and rope diameter confirmed adherence of all ropes to those construction specifications. Mechanical properties of strength and ductility were determined by accepted methods for the ropes and wires from the ropes. Individual wires from one rope failed to meet minimum wire ductility values. Wire chemical composition varied in average carbon levels, from 0.70 to 0.78 wt pct, and in manganese content, from 0.45 to 0.80 wt pct. One manufacturer's product contained 1 to 3 wt pct Ni and Cr. Heavily wrought pearlitic steel microstructures were porous and contained inclusions. Cold work variations were evidenced by wrought grain width. Recorded anomalies reflected the condition of the manu-factured products. The report provides data that compare the three wire ropes studied, but cannot verify the effects that these conditions or anomalies have on rope service life.

Jan 1, 1983

By Stanley P. Jacobsen

Samples of fine coal refuse were obtained from 11 coal preparation plants throughout the United States. These samples were characterized by ash analysis, particle size, and mineral composition. From the characterization, geographical locations, and the dewatering equipment being used by the plants, five sites were selected for obtaining bulk fine refuse samples. The selected coal preparation plants were using for final dewatering thickeners followed by: a vacuum disc filter, a filter press, a belt press filter, a centrifuge, and a settling pond. None were using thermal drying. The moisture content of the final cake varied from approximately 23% to 50% depending upon the feed material, flocculant addition, and the type of equipment. The filter press gave the lowest moisture content followed by a belt press and then either a centrifuge or vacuum filter. The centrifuge products were all dried to an approximate 5% moisture in a thermal dryer.

Jan 1, 1981

By G. F. Friel

A series of experiments in the U.S. Bureau of Mines Safety Research Coal Mine at the Pittsburgh Research Center evaluated the effects of crosscuts on the travel time of carbon monoxide (CO) along an entry to improve the accuracy of a mine-fire locator program. Three entries, ten single crosscuts, and three double crosscuts were instrumented with CO sensors. One-percent CO in nitrogen was released and monitored as it traveled the entries. In addition to dispersion of CO at the front of the CO wave, CO was entrained from the entry into the crosscuts. It was determined for an entry and single-crosscut configuration that the measured travel time for a concentration change of 5 ppm was 27% greater than the predicted time based upon entry volume only, but 13% less than the predicted time based upon entry and crosscut volumes. For an entry and double-crosscut configuration, the measured travel time for the same concentration change was 25% greater than the predicted time based upon entry volume only, but 10% less than the predicted time based upon entry and crosscut volumes. An effective dispersion coefficient for CO dispersion along one of the entries was estimated to be 1.5 m2/ s.

Jan 1, 2010

By R. G. Knickerbocker, David Schlain, F. K. Shelton, J. H. Jacobs

"Many manganese ores contain from 0.1 to several percent cobalt. If such ores arc used for the production of ferromanganese, the cobalt is lost; on the other hand, if they are used for the production of electrolytic manganese, the cobalt can be recovered during the purification of the electrolyte.The production of cobalt in the United States is insignificant compared to the amount consumed, most of which is imported from the Belgian Congo. Cobalt-bearing manganese ores may therefore constitute an important reserve of cobalt in times of emergency. Moreover, the combined value of manganese and cobalt in some ores may be sufficient to warrant the recovery of both metals by the electrolytic manganese process, whereas the recovery of either manganese or cobalt alone might not be economically feasible.In view of the potential importance of manganese ores as a source of cobalt, a survey has boon made of the cobalt content of manganese ores. Most of the data have been obtained from analyses made in the Bureau of Mines, but valuable data have also been obtained from publications of the Geological Survey, various State publications, and other sources. Unfortunately, most published analyses of manganese ores do not include cobalt determinations; when such analyses were fairly detailed, but did not include cobalt, it was presumed that cobalt was not present in significant quantity.Information on the cobalt content of domestic manganese ores is given in table 1. Ores containing 0.1 percent or more cobalt are listed in table 2, and the districts in which such ores occur are shown in figure 1. Most of the known cobalt-bearing manganese ores occur in the southeastern part of the United States. A group of deposits in central Arizona and a few scattered deposits in other States also' contain cobalt."

Apr 1, 1946

By W. C. Hudson

"Sillimanite, kyanite, and andalusite are aluminum silicates having the same chemical composition (Al2Si05) and are used in the ceramic industry for the manufacture of high-grade refractories. ""Natural sillimanite with added corundum or other alumina to just short of mullite 2SiO2) proportions is unequalled for jobs where strength at high temperatures, resistance to spalling, and resistance to slagging by acid slags is desired. High-grade porcelain ware also requires these minerals.""At the same cost, sillimanite would be preferred for most uses, but the lack of any large source of sillimanite has given economic preference to kyanite or andalusite for special refractories and high-grade porcelain ware.""3/The possible economic value of the sillimanite schist in the piedmont Plateau was first recognized by Dr. L. L. Smith, of the University of South Carolina, who published an article in the Engineering and Mining Journal, August 1943, on an occurrence of sillimanite schist in South Carolina.The Bureau of Mines was interested in developing a large source of sillimanite to relieve the shortage of high-grade refractories, and initiated a project to locate the ore-bearing areas in Georgia and South Carolina and to develop the most favorable ones.Two hundred and seventy-eight outcrops of sillimanite-bearing schists were found by a Bureau of Mines engineer.4/ The schist occurs irregularly throughout a belt extending from Talbot County, Georgia; to Spartanburg County, South Carolina, about 220•miIes long and approximately 15 miles in maximum width. The Bureau drilled four areas of the more coarsely crystallized schist in Georgia and South Carolina:In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon; chief; conducts preliminary examinations, performs the actual exploratory work; and prepares the final report. The Metallurgical Branch;.R. G. Knickerbocker; chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director."

Sep 1, 1946

By R. E. Brewwe

"INTRODUCTION Anyone who has had frequent occasion to compare methods of analysis and testing as employed in European countries with those used in the United States has felt the need of a table or graph giving the relationship between the units of measurement of finely powdered materials. Most of the few published comparisons include only two series of sieves and often require tedious interpolations to adapt the data of one series to the series more familiar to the reader. To eliminate such deficiencies, the author hopes that the discussion and comparison of fine-series sieve sizes presented here will conserve the time of interested research workers.ACKNOWLEDGMENTSThe author is deeply indebted to Virginia B. Strathearn, scientific aide, for help in compiling the information from the literature and to W. A. Solvig, senior chemist, for valuable suggestions in preparing the manuscript.SQUARE-MESH-SIEVE SERIES OF DIFFERENT COUNTRIESSieving analyses of powdered materials have been placed on a comparable basis in different countries by the introduction and adoption of standard sieve-scale series. Series of wire-cloth square-mesh sieves in common I oratory and industrial use include: Institution of Mining and Metallurgy standard laboratory screens (I.M.M.); British Standards Institution standard for fine-mesh test sieves (B.S. or B.S.I.); Tyler standard sereer-scale sieves; United States standard sieve series; Deutsche Industrial-Nermen (DIN); and the standard control sieves of the Association Francaise de Normalisation (AFNOR). With the exception of the I.M.M. series in which the opening is equal to the diameter of the wire, the general proportions of the various series of sieves are similar. The size of British and American sieves is designated by the number of meshes or openings per linear inch or, more recently, by the number of microns per linear sieve opening. In a technical sense the word ""mesh"" is meaningless, unless the diameter of the wire is also given, so that the size of the opening can be determined. On the Continent sieves are designated either by the nunber of Mesh per linear centimeter or by the number of openings per square centimeter."

Jul 1, 1944

By Lyman C. Hitchcock

The objective of this program was to determine the minimum luminance requirements for underground coal mining work from the working face to the first transfer point. The resulting data encompasses 114 visual tasks from conventional continuous and longwall mining methods representing the salient visual tasks found in the jobs listed. Cutter Operator Roof Bolter Face Drill Operator Airdox Operator Longwall Jackman Shuttle Car Operator Loader Operator Shot Fireman Continuous Miner Operator Longwall Head Conveyor Operator Longwall Tail Conveyor Operator

Jan 1, 1973

By J. P. Powell

The increased costs of exploration and drilling of new oil fields and the continued success of water flooding in nearly depleted oil fields have created a demand for information on the results obtained from individual projects. The Bureau of Mines has published several reports concerning water-flood activity in the Mid continent area and at the request of the industry has continued to collect and disseminate this information. This report was written in response to these requests. It describes in detail the water-flooding projects in Anderson, Franklin, Linn, and Miami Counties, Kans., and includes methods of water treating and the results obtained. The production histories of each county and many water-flood projects are shown graphically from the date of the first development. Maps of most of the major projects, showing their status as of January 1, 1953 are presented also. The practice of injecting water to stimulate oil production was legalized in Kansas in 1935, and the first water-flooding project authorized in this four-county area was initiated by the Texas Co. in December 1935 in Linn County, Forty-nine projects2/ initiated in the area to January 1953 are estimated to have recovered approximately 10 million barrels of oil that could not have been produced by methods used previously. About 7,900 productive acres had been, or are, flooded by these projects, and approximately 1.36 million barrels of water had been injected.

Jan 1, 1953

By Eric E. Ungar

Some fundamental facts regarding noise are summarized. Guidelines for reducing plant noise are indicated, and simple means are discussed for determining, whether quieting of specific equipment items will reduce plant noise significantly. Design and installation recommendations are made for quieting chutes by means of dams, impact cushioning pads, impact shields, and damping materials, and for quieting; screens by means of resilient decks, lined screen bottoms, drive mechanism enclosures, and side plate additions. A brief account is appended of the wear and productivity performance of resilient materials observed in three cleaning plants.

Jan 1, 1976

This report is a proceedings of a briefing recently sponsored by the Bureau of Mines at which Bureau personnel presented findings from their research efforts to improve steelmaking techology currently used in the United States. The papers contained in this report address many areas of concern to the iron and steelmaking industry. Among these are improving arc stability in electric arc furnaces, preheating ferrous scrap to reduce energy consumption, fluorspar substitutes in steel-making, basic steelmaking refractories, corrosion of iron-based materials, improvements in stainless steel acid pickling processes, recycling of stainless steel dusts and other wastes, and use of wastes as a source of zinc for electro/galvanizing.

Jan 1, 1988

By D. Pennington

Ground-water levels and subsidence have been monitored over a longwall panel of a deep coal mining operation located in western Pennsylvania. The monitoring network includes eleven ground-water monitoring wells completed to measure water level changes in separate shallow and deep aquifer zone-, and 50-foot surveyed subsidence stations parallel and perpendicular to the panel centerline. Monthly monitoring data were collected during the premining, mining, and postmining tine periods. Aquifer testing and borehole geophysical logging were conducted during premining, and post-mining conditions to document any changes in aquifer properties and ground-water flow patterns. Results indicate ground-water declines were located with respect to the mining face and mined longwall panel. Dewatering of the deep aquifer zone caused a significant water level decline in deep wells; however, the shallow aquifer zone was isolated fro major impacts by an aquitardal layer during, the, one-year period. Transmissivity data were greatly impacted by fracturing, in the highly anisotropic aquifer system. Borehole geophysical logging indicated changes in ground-water flow patterns and zones of increased fracturing from subsidence.

Jan 1, 1984

By V. Vern Hutchison

This selected list contains 829 entries with citations to Bureau of Mines publications related to petroleum and natural gas, which were released during the 1961-1970 period. Some entries are multiple in nature, resulting in a total of 881 citations.

Jan 1, 1972

By John C. Edwards

To increase the capability to predict the effectiveness of a flame arrester in the cooling of hot combustion gases expelled through a flame arrester, the U.S. Bureau of Mines developed an equilibrium. model and one-and three-dimensional transient thermal models of a flame arrester, which were used to predict the temperature evolution within the arrester and the maximum temperature at the external surface of the arrester. The models account for convective and conductive heat transport within the arrester and radiative losses at the exit surface. The gas flow through the arrester is established from an empirically derived relationship between the gas velocity and the pressure gradient across the arrester. Lateral heat loss from the arrester to the enclosure wall is accounted for in the three-dimensional model. The model calculations for maximum outside surface temperature of the arrester showed an approximate agreement with measured values for vent-area-to-enclosure-volume ratios between 12 and 28 in2?ft-3.

Jan 1, 2010

By J. M. Mutmansky, L. Xu

"IntroductionSince the establishment of the star,just concentration of 2 mg/m3, a strong effort has made by mining engineers and researchers to provide better dust control equipment and procedures for underground coal mines.Particular areas of success have been implementation of better coal-cutting strategy to control dust generation, better design of water sprays for dust suppression and air movement, use of scrubbers, and improved design of face ventilation systems. A drastic improvement occurred over time such that the average dust concentrations for continuous miner operators dropped from 6.5 mg/m3 in 1968 to 1.3 mg/m3 in 1980 and for auger, cutter, longwall, and roof bolter occupations from 2.7 mg/m3 in 1973 to 1.6 mg/m3 in 1980 (Niewiadomski, 1983).While dust concentrations in mining sections have been dropping considerably, one problem area has been mining sections where quartz is a considerable portion of the airborne dust. The federal regulations require that quartz content must be held below 0.1 mg/m3 in the air regardless of the concentration of the total dust. This legislation limits the allowable dust concentration to a ""reduced standard"" of 10/ (% quartz) when the quartz content of respirable dust in the mine atmosphere is more than 5%. Today, approximately one-third of underground coal mining operations have designated areas with more stringent dust standards in place, and many mines experience considerable difficulty in meeting these standards (Jankowski, and Babbitt, 1989).It is well known that metal miners subjected to respirable dusts high in quartz have a higher incidence of silicosis than those exposed to dust low in quartz. However, the role of quartz in the development of coal workers' pneumoconiosis is still a highly controversial question, in spite of the large number of research projects devoted to this subject over the last 20 years. Because coal seams contain less quartz than metal ores and quartz often comes from sources outside the coal seam (e.g., roof and floor), it is difficult to relate studies that deal with the quartz content in coal seams and the incidence of coal workers' pneumoconiosis. Hamilton, Ogden, and Vincent (1983) have provided a plausible explanation for the incidence of the disease by hypothesizing that the quartz content does not affect the probability of developing pneumoconiosis until some threshold value (generally thought to be about 10%) is exceeded.The objective of the research studies summarized here was to obtain a better understanding of quartz occurrences in airborne coal mine dust by studying the variations of the quartz levels in different dust sizes and the relationship between the quartz content in airborne coal mine dust and the quartz content in the mined material. The implications of the results to control of dust in high-quartz sections will also be discussed."

Mar 1, 1992

By H. L. Bibbs, H. D. Snedden

"INTRODUCTION The use of beryllium and its alloys has increased rapidly during the last decade. Further expansion of its use is limited; in part, by lack of adequately developed ore reserves. The principal commercial beryllium mineral is beryl, which is found chiefly in pegmatites and produced for market as a byproduct of the mica and feldspar industries. The coarse beryl is mined selectively, sobbed and sorted by hand, and then sold without further beneficiation. The known reserves of coarse beryl are small. No method has been available for concentrating small disseminated beryl crystals, so ores of this type have not been mined or have been left on waste dumps. Disseminated ore in low-grade unmined areas and waste dumps on developed properties is a potential source of beryl, provided a method is developed for its beneficiation.Published literature on the concentration of beryl is lacking in detail or deals chiefly with tests on artificial mixtures of pure minerals, and procedures as given were not applicable to the beryl ores tested at the Salt Lake Station. The testing procedures described in this report are independent developments. By employing these procedures, beryl was satisfactorily con¬centrated from several run-of-mine and dump ores, although these ores wore low in grade and part of the contained beryl was finely crystalline and disseminated.Beryl, quartz, and feldspar, when ground to flotation sizes, are so alike in color and general appearance that they cannot he distinguished by visual observation. The progress of the work depended on rapid determination of the grade of test products by means of the petrographic microscope. Small samples of concentrates and tailings were often cut after each addition of reagents, dried, and examined under the microscope."

May 1, 1947

By G. B. Shea

Among the many engineering problems directly related to conservation in the petroleum industry, that of crude-oil emulsions continues to be important. Emulsions of water and oil always have constituted one of the most serious forms of waste in the oil fields, and the necessity of dehydrating emulsified crude petroleum to obtain marketable or pipe-line oil confronts operators in many fields with a major operating problem. In 1926 the Bureau of Mines published a comprehensive treatise s on oil-field emulsions dealing with field conditions, practical methods of dehydration, and physicochemical characteristics of the formation and resolution of emulsions. Although this bulletin is still available and may be obtained from the Superintendent of Documents, Washington, D. C., and although its contents are a valuable reference on the subject of emulsions, knowledge regarding the physical properties of emulsions and the phenomena of dehydration has increased greatly within the last decade. With the information gained through continued scientific research, substantial improvements have been made in the art of resolving petroleum emulsions. Moreover, in recent years there has been a growing realization of the importance of emulsion-preventive measures that has led to more critical examination of the causes of emulsions and methods of eliminating or at least reducing the degree of emulsification. Conditions causing agitation and commingling of oil and water and the formation of "cut oil" often are within the control of the producer, thereby making it possible to utilize preventive or remedial measures by which emulsification may be minimized or avoided. In fact, many companies have materially reduced their treating costs as a result of careful studies in emulsion prevention and proper handling of "wet" production. Of course, in many instances preventive measures or the correction of conditions causing emulsification cannot be achieved practically or economically, and the emulsions that form must be treated regardless of the care exercised or the money spent in attempting to prevent their formation.

Jan 1, 1939

By S. H. Ash

THE ANTHRACITE region of Pennsylvania contains over nine-tenths of the total anthracite deposits of North America and produces all but an insignificant proportion of the total output of anthracite in the Nation. The whole economy of the northeastern section of the United States depends, to a large extent, on the mining of Pennsylvania anthracite, which is shipped to New Jersey, New York, and New England and is a principal source of energy and heat for that entire region. The responsibility of the Federal Government for developing an engineering method that will prevent inundation of the Pennsylvania anthracite mines and keep them in operation has long been recognized. To obtain a reliable picture of the anthracite-mine-water problem and to solve that problem, it is necessary to have factual data on the volume and the quality and character of the mine water handled by the pumping plants in the anthracite region, as well as the kinds of pumps utilized and problems concerning their operation.

Jan 1, 1953