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By A. J. Fejes

The purpose of this Bureau of Mines report is to provide mining industry personnel and regulatory authorities with a subsidence-reference list and annotated bibliography that will aid them in locating subsidence information and in developing their own subsidence information sources. Over 700 references are listed in the Bureau's subsidence information center bibliography; approximately 600 of these references were obtained for assessment. Of these 600 references, 167 were selected to be rated, categorized, and annotated. All literature referenced in this report was published prior to 1984. Table 1 is a cross - referenced index that classifies and rates selected references with respect to specific keywords. References are rated not on quality of content but rather on applicability to given subject areas. Appendix A is an annotated bibliography of the references listed in table 1 and provides further information of each article to aid the user in selecting articles for specific areas of subsidence technology. Appendix B is a copy of the subsidence information center bibliography.

Jan 1, 1985

By Roy T. Sorensen

The Bureau of Mines has investigated the recovery of cell-grade alu-mina by RCI leaching of calcined kaolin in the alumina miniplant at its Boulder City (NV) Engineering Laboratory. Classification and thickening were used for separating aluminum chloride leach liquor from the siliceous residue generated in the acid leaching step of the clay-HCI process. Coarse solids were classified from fines at 115 mesh and countercurrently washed in three additional spiral classifiers. Fines were treated in a conventional five-thickener, countercurrent decantation circuit. When this method was applied to the solids-liquid separation of slurry from RCI leaching of minus lO-mesh calcined kaolin, 75 pct of the residue reported as classifier sands and 25 pct as thickener underflow. Predicted individual classifier and thickener area requirements were 6 and 25 ft2/tpd, respectively. Total thickener circuit flocculant requirement was 2.4 lb/ton solids. Aluminum chloride pregnant liquor was produced that analyzed 8.4 pct A1203 and contained more than 97 pct of the alumina in the liquid phase of the slurry. Bench-scale settling tests were used to correlate fines content of leach residue to thickener area and flocculant requirements.

Jan 1, 1983

By Donald I. Kurth

The Bureau of Mines conducted experimental work on comminuting coal. The size distributions of coarse fragments and fine particles were obtained under different modes of energy application--drop, impact crushing, wedge impact, compression, and shear tests. Four levels of energy application were used in the impact crushing and wedge impact tests. Airborne dust and respirable air-borne dust distributions were obtained for the impact crushing and wedge impact tests. Analyses of nonairborne dust and coarse fragment-fine particle distributions were carried out on impact, wedge, compression, and shear tests. The experimental size data on nonairborne dust were fitted to normal, log-normal, power law, Weibull, log-Weibull, and exponential distribution functions. Both the nonairborne dust and the coarse fragment-fine particle size distributions are best described by Weibull distributions. For the impact crushing tests, mean product size was found to be inversely related to specific crushing energy. The particle counts in a given size range of airborne and nonairborne dust were found to increase with increased input energy and specific crushing energy. However, in another sense the particle distributions were independent of energy level; that is, the percent-ages in a given size range were approximately constant regardless of energy level. Respirable airborne dust was related to respirable-size nonairborne dust by a power law.

Jan 1, 1975

By Richard D. Miller

This publication contains routine analyses and related source data for 434 gas samples from 16 States. These samples were collected during calendar year 1961 as part of the continuous survey for the occurrence of helium in natural gas conducted by the Helium Activity of the Bureau of Mines. The analyses herein were made by mass spectrometer and Frost helium apparatus. The most important helium resource discovery made during 1961 was the Table Mesa field in San Juan County, N. Mex. This field, Which has an estimated recoverable helium reserve of 850 million cubic feet, is now supplying gas containing approximately 5.4 percent helium to the Bureau of Mines Navajo Helium Plant at Shiprock, N. Mex.

Jan 1, 1964

By Richard D. Miller

This publication contains routine analyses and related source data for 434 gas samples from 16 States. These samples were collected during calendar year 1961 as part of the continuous survey for the occurrence of helium in natural gas conducted by the Helium Activity of the Bureau of Mines. The analyses herein were made by mass spectrometer and Frost helium apparatus. The most important helium resource discovery made during 1961 was the Table Mesa field in San Juan County, N. Mex. This field, Which has an estimated recoverable helium reserve of 850 million cubic feet, is now supplying gas containing approximately 5.4 percent helium to the Bureau of Mines Navajo Helium Plant at Shiprock, N. Mex.

Jan 1, 1964

By George S. Rice, F. B. LANEY, A. J. Lanza, Edwin Higgins

Under its organic act the Federal Bureau of Mines is directed to conduct investigations relating to the improvement of health conditions in the mineral industries. This report describes the lead and zino deposits and the mining methods employed in the sheet-ground area of the Joplin district, Missouri, and discusses the causes and the methods of abating rock dust in the mines, the chemical and physical characteristics of the dust, and the quantities present in mine air. Although the preliminary investigation included a number of the "soft-ground" mines, the writer spent the larger part of his time in the sheet-ground mines, for in them alone was siliceous dust found in appreciable quantities. Some results of the preliminary investigation have been published by the Bureau of Mines in Technical Paper 105.a The territory covered in t~lCpreliminary investigation, during the period between November 7 and December 6, 1914, embraced parts of Jasper, Lawrence, Newton, and Greene Counties, Mo., and outlying districts in Kansas and Oklahoma. The remainder of the field work, to which 84 days during the period from February 9 to July 19, 1915, were devoted, was confined to the sheet-ground mines, the most important of which are situated in the vicinity of Joplin, Webb City, Carterville, and other smaller near-by towns in Jasper County, Mo.

Jan 1, 1917

By K. B. Higbie

The quantitative separation of tantalum from columbium has been obtained through several liquid-liquid extraction processes. The valuable metals are separated by selective extraction from organic feed solution using a mineral acid or by selective extraction from aqueous feed solutions employing an organic solvent. The greatest degree of separation was obtained when organic ketones, particularly methyl isobutyl ketone, were used. Approximately 200 combinations of various organic solvents and mineral acids were tested as possible separation systems in which the tantalum or columbium content was extracted from organic solutions of the anhydrous pentachlorides.

Jan 1, 1956

By W. W. Adams

Increased employment and a lower accident-frequency rate were the outstanding features of the metal- and nonmetal-mining4 industries of the United States in 1939 compared with 1933, according to reports furnished by individual mining companies to the Bureau of Vines, United States Department of the Interior. Except for 1937, the reports for 1939 showed gains both in number of employees and number of mar -hours worked over all years since 1929. The accident-frequency rate per million man-hours of exposure to mining hazards was lower than in any year since 1925. Reports for 1939 revealed a total of 111,909 men employed in and about mines, an increase of inure than 8 percent over 1931 The total volume of labor performed at all mires was slightly more than 299 million plan-hours, an increase of mare than 10 percent over 1938. As these gains suggest, the average employee had a longer period of work in 1939, the increase amounting to r workdays per employee.

Jan 1, 1941

By R. A. Friedel

THE IMPORTANCE of infrared and ultraviolet-visible spectrometry in studies of the structure of coal and similar substances is described. Special experimental techniques have been developed for these studies. Thin sections of coal are preferred, but halide pellets are easier to prepare. Information obtained from infrared spectra on chemical functional groups has been discussed; the importance of both intensities and wavelengths of absorption bands has been emphasized. Functional groups assigned include aliphatic and aromatic CH, methylene and methyl groups, hydrogen-bonded hydroxyls, hydrogen-bonded and chelated carbonyls, phenolic structures, minerals, and aromatic structures that are benzenoid or polynuclear. Infrared studies of structures of coal extracts, distillates, and reaction products of various processes, both chemical and physical, are discussed. Coallike infrared spectra of chars of model compounds have been utilized extensively in studies of coal structure. Ultraviolet-visible absorption spectra of coals show a lack of fine structure and low spectral intensities. These results have been applied to the questions of the chemical and physical structure of coal, particularly the question of polynuclear aromaticity of coals. The color of coal is also treated. The physical-chemical origin of the color of coal may be due to free radicals, as interesting correlations of ultraviolet-visible spectra with electron paramagnetic resonance have been obtained. The optical color of coal has been explained and simulation of the color changes observed in thin sections has been carried out, The spectra and structure of coal derivatives and other carbonaceous materials are also discussed. Possible sources of error in absorption spectral measurements are pointed out. Limited measurements of the ultraviolet-visible reflectance spectra of coal are described.

Jan 1, 1967

By Clarence Karr

In 1955 the Federal Bureau of Mines established a low-temperature tar laboratory at its new Appalachian Experiment Station in Morgantown, W. Va. The objective of the laboratory is to investigate the yields and chemical and physical properties of tars from low-temperature carbonization of coal, to investigate means of economically upgrading these tars, and to make available to industry and the public essential data for increasing coal utilization through the establishment of a new coal-chemical industry, based on the utilization of low-temperature tars. Because of the obvious economic significance of phenols, as well as the relative ease with which they can be separated and analyzed, initial research has centered mainly around this class of tar constituents. It was realized early that no listing of phenols and their physical properties existed that included enough compounds to be practicable. The purpose of this paper is to make such a compilation available.

Jan 1, 1957

By Reinhardt Thiessen

Views and conceptions of the origin, composition, and general nature of coal differ so widely that to determine the real extent of actual knowledge is no easy matter. The chemist finds difficulty in attacking the chemical problems and the engineer lacks a broad chemical basis for the study of his problems. Thus the economical and efficient utilization of coal in the industries suffers from a lack of knowledge of the composition of coal itself. Most scientists interested in this matter, as has been brought out in discussions during the recent investigation of coal problems, appear to have only a vague idea of the components of coal and their origin. Some are even in doubt as to whether substances derived from the wood and resins of plants form a part of coal; and few seem to have more than the dimmest idea of what are the components of coal, the condition in which these now exist, and the transformations that they haye undergone. Although during the paiilt century or more many co.rrect observations have been made and recorded, these were falsely or inadequately interpreted, so that many of the interpretations rendered are contradictory. As a result there has been great confusion. Many of the observations made in the past, although accurate and correct, could not be explained, because the principles involved in a correct solution of the problem were not then known. For example, Parkinson, Hutton, Petzhold, Guembel, and others made valuable discoveries regarding the processes by which plant substances are transformed into coal, but as the principles involved are those of colloidal chemistry, a science not known to the scientific world of that time, the observed facts could not be interpreted and the solution of the whole problem was blocked. The explanation of the true meaning of the alternating bright and dull bands so familiar in all ordinary bituminous coals afforCls another example. This banding has been observed and recorded from the earliest times, and has led to the forming of many false theories. Some gAologists, for example, have endeavored to explain the bands as due to alternating climatic conditions during the coal-forming period. Had the geologists known the true nature of coal they could not have made this mistake nor many others made in the past. To fill in a few of these gaps and to clarify some of the existing confusion is the aim of this paper. The immediate cause that led the author to investigate further the composition of coal and the origin and structure of its constituents was that when an attempt was made to discover the meaning of the coking and noncoking properties of coal a more exact knowledge of the nature of coal was required than was then available.

Jan 1, 1920

By W. F. Watts

In 1980 the Bureau of Mines developed the Mine Inspection Data Analysis System (MIDAS). MIDAS is a computerized, industrial hygiene data base capable of statistically analyzing environmental data collected in coal and noncoal mines and mills by Mine Safety and Health Administration (MSHA) inspectors or mine operators. The objectives of this report are to describe the current contents of MIDAS, to report analyses of coal and noncoal mine respirable dust samples collected by MSHA inspectors and to evaluate the proposed change in the metal and nonmetal respirable dust standard from a formula based upon the percentage of quartz identified in the sample to 100 µg/m3 of respirable quartz. Based on samples collected by MSHA inspectors, changing the noncoal respirable dust standard would result in 4 pct fewer samples with dust concentrations exceeding the standard. Analysis of respirable coal dust data collected by MSHA inspectors showed that mines with longwall plows or shears had the highest geometric mean concentrations (1.64 and 1.29 mg/m3, respectively). Mine operations using continuous rippers out-numbered longwall mine operations about 10 to 1 and had a geometric mean concentration of 0.66 mg/m3.

Jan 1, 1987

By W. J. McKenna

This paper, describing the milling practice at tine lead-zinc concentrator of the International Smelting Co., is one of a series of papers on milling methods being prepared by the United States Bureau of nines. The concentrator is operated as a unit of the International Smelting Co. and is located about 40 miles southwest of Salt Lake City, at Tooele, Utah. The Tooele Valley Railroad, operating between the plant and Warner, Utah, a distance of 6.5 miles, makes connection with both the Union Pacific and Denver & Rio Grande Railroads.

Jan 1, 1933

By Joseph J. Wallace

1. From the standpoint of present production and recoverable reserves, there are two beds of major importance in Allegheny County -Pittsburgh and Upper Freeport -and one of lesser importance -Redstone. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 short tons per acre-foot of coal in place, are estimated at 832 million short tons as of January 1, 1953. Of this total, 768 million short tons is in beds 28 inches and more thick. Areas in some beds were omitted from the estimate because available data relative to the bed characteristics are too meager for making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1953

By D. H. Platt

Gypsum and gypsite, used in the manufacture of plaster and plaster products, have been mined from deposits near Acme, Hardeman County, Tex., for more than 30 years. The Certain-toed Products Corp., 120 East Lancaster St., Ardmore, Pa., operates the Acme, Tex., mine. Underground hauling was done with storage-battery and Diesel-electric-powered shuttle cars. Many mining companies and individuals have manifested interest in all types of equipment powered by Diesel or Diesel-electric units, as attested by the recent increase in use of Diesel-powered equipment in underground metal and nonmetal mines. The purpose of this paper is to describe the manner in which a storage battery-powered Joy Model 60D2 shuttle car was converted to Diesel-electric power. The conversion was made, at the instance of the operating company, by Stewart & Stevens on Services, 4801 Lemon Ave., Dallas, Tex. This is believed to be the only such converted shuttle car in use.

Jan 1, 1950

By James E. Norman

[The flotation of mica is mentioned frequently in the literature, but must of the references have dealt with the recovery of mica by the old anionic collectors. The first use of the new cationic reagents indicated their superiority- as collectors in the flotation and a. agglomerate tabling of micas, feldspars, quartz, clay, and other acidic mineral, but the separation n of these minerals from each other necessitated study of the flotation of each mineral.]

Jan 1, 1941

By James E. Norman

[The flotation of mica is mentioned frequently in the literature, but most of the references have dealt with the recovery of mica by the old anionic collectors. The first use of the new cationic reagents indicated their superiority as collectors in the flotation and agglomerate tabling of micas, feldspars, guartz, clay, and other acidic minerals, but the separation of these minerals from each other necessitated of the study of the flotation of each mineral.]

Jan 1, 1941

By C. M. Harrer

This paper describes the location and general features of iron occurrences in Colorado. Most of the deposits were examined; many are in forested and mountainous areas at altitudes of 5,000 to 13,700 feet. Iron is known to occur in 30 counties of western Colorado. Transporting the ore to market is a handicapping economic factor involving long truck and railroad hauls; the nearest purchaser of smelting ores is the Colorado Fuel and Iron Corp., at Pueblo, Colo. When the ore can be sold locally for special purposes and at higher prices than can be obtained at iron smelters, small-scale operations can supply that market.

Jan 1, 1959

Humankind's interest in measurement of human physical strength probably dates to the first humans. At that time, life was truly a struggle in which the fittest survived. To a great extent, fittest meant strongest. Interestingly, current interest in human physical strength in the workplace stems from 1970-1980s vintage research demonstrating that persons with adequate physical strength are less likely to be injured on physically demanding jobs. Survival in many modem workplaces may still be a case of survival of the strongest. There is, however, a flip side to this issue - that persons with limited strength are more likely to be injured on "hard" jobs. To address this problem, we can apply what we know about physical strength to job design. "Hard" jobs can be redesigned to be within the physical strength capability of most people. Since physical strength is important to these jobs, we must find ways to quantify it through testing. This publication concerns human physical strength testing. Its purpose is not to recommend any particular type of testing, but rather to describe the types of testing available and their uses. It is up to each individual user of strength testing to decide which testing technique is most appropriate for his or her particular application. This booklet discusses four types of strength testing: isometric, isoinertial, psychophysical, and isokinetic. Human Strength Before describing the different types of strength measurement, we must define the term "strength" and explain the concept of strength measurement. Strength is defined as the capacity to produce force or torque with voluntary muscle contraction. Maximum strength is defined as the capacity to produce force or torque with a maximum voluntary muscle contraction.(1,2) These definitions include some key words that must be explained. A voluntary muscle contraction is "voluntary." When a person's physical strength is measured, only the effort the person willingly puts forth at the time is measured. Thus, when we test a person's "maximum strength," we are not measuring his or her actual maximum, but some lesser value representing what he or she is comfortable expressing at the time with the existing equipment and environmental conditions. Interestingly, when researchers startled persons being tested (e.g., by setting off a starter's pistol behind them), they have found significant increases in measured strength.(3) It has been hypothesized that the lower strength displayed during normal testing provides a margin of safety against overloading and damaging muscle tissue. The test equipment and the tested person's familiarity with the process also influence the "voluntary" strength output. The interface between the tested person and the test equipment is particularly important. A poorly designed interface induces localized tissue pressures that vary from uncomfortable to painful. In this situation, testers are measuring voluntary discomfort tolerance - not strength. It is important for strength researchers to keep the "voluntary" nature of their data in mind when they are designing their equipment and protocols.

Jan 1, 1998

By Manuel Gomez, V. F. Parry, John B. Goodman

"INTRODUCTION The need for an accurate and precise analytical method for determining moisture in coals of high water content has been recognized by the coal industry as well as the fuel technologist. Interest in this particular phase of coal technology extends back to the early work of German investigators on the brown coals of Central Europe. Studies by these workers led to the establishment of a direct immiscible liquid-distillation method 4/ as the accepted moisture determining technique in European laboratories. Direct moisture determining methods, those methods that utilize various techniques to drive off the water from a given sample of coal and either collect the water in a calibrated receiver or selectively trap the water driven off in a suitable absorber, have found little favor in the United States. They have been treated merely as research tools.5/ The problem of moisture determination in low-rank coals of the United States has not been given much consideration because such coals contribute only about 2 percent of the total United States production. With renewed activity in low-temperature carbonization and with the growth of interest in coal and coal-tar hydrogenation, the American coals of lover rank containing 20 to 40 percent bed moisture will be subjected to extensive investigation. If the low-rank coals of the United States are to be accurately appraised, the need for qualitative and quantitative analytical proceeded becomes more pronounced. These coals, especially the lignites of Texas and North Dakota, are highly susceptible to oxidation, a process that proceeds to a greater or less extort when low-rank, high-moisture coals are treated by oven-drying methods. The extent of this atmospheric oxidation has been described and evaluated by numerous workers. 7/In many respects, the problem of moisture determination in low-rank coals, those found in the United States and the high-moisture coals of Central Europe, is similar. Conversely, the problem of moisture determination assumes a different aspect when the coals of the eastern and the middle-west sections of the United States are considered. Present methods, the loss in weight gravimetic-type procedures, serve adequately to test these low-moisture coals. The determination of moisture in coals containing 20 to 40 percent water should be approached from a direct method rather than from an indirect gravimetic-type procedure because of the oxidative tendencies of these coals and the demonstratrated inability of a loss-in-weight technique to remove all the water in a given sample of coal."

May 1, 1953