Search Documents

By John E. Conley

Of the three chemical elements most vitally essential for plant growth the United States, before World War I, had developed ample domestic supplies of but one-phosphorus. During and shortly after the war period, the fixation of nitrogen was greatly expanded in this country, as in many others, insuring a supply adequate for agriculture as well as for munitions. However, in spite of a search for sources of the third element, potassium, which began years before the war, attained almost frantic intensity between 1914 and 1919, and continued for 10 years thereafter, it was not until 1921 that the American Trona Corporation put its Searles Lake operations into continuous production. This company in 1926 became The American Potash & Chemical Co. but has never supplied much more than 15 percent of the potash consumed in the American market. Likewise, though discovered in 1921 in drill cuttings from oil wells, it was not until 1926 that domestic deposits of potassium salts adequate to render the United States independent of foreign sources of supply were proved to occur in the Permian Basin of Texas and New Mexico.

Jan 1, 1944

By C. L. Karr

U.S. Bureau of Mines (USBM) research has shown that fuzzy logic and genetic algorithms (GA's) have great potential for industrial process control. A technique has been developed by the USBM in which GA's are used to substantially reduce the time needed to design fuzzy logic controllers (FLC's).This technique shows promise as an efficient, robust approach to developing control systems. The research described in this report is twofold. First, the basic approach to developing an FLC using GA's is presented. The GA-designed FLC is developed for a specific physical system, a pH titration system. Second, empirical results are presented in which variations in the FLC implementation are compared. Specifically, the effects of altering five aspects of the pH FLC are considered: (1) membership function form, (2) number of fuzzy classes, (3) the center-of-area method, (4) implication operator, and (5) fuzzy rule form. Results indicate that (1) the technique in which GA's are used to design FLC's is effective, and (2) when this technique is used, variations in FLC implementation have little effect on FLC performance in a chosen control problem.

Jan 1, 2010

By H. M. Thorne

Oil shale, a potential source of products presently obtained from petroleum, is found in many countries. The most extensive known deposits from the standpoint of potential shale oil in place are those in Brazil and the United States of America. Mining methods used for oil shale range from open-pit operations for shallow deposits to room-and-pillar and longwall techniques for deposits with thick overburdens. Oil shales from different sources vary greatly in the amounts and types of organic and inorganic constituents. By retorting, the organic material is converted to oil, gas, and coke. The largest percentages of oil are obtained from materials having the highest hydrogen content. Over 2,000 retorting systems have been patented, but only a few have been used industrially, and no single process seems best for all types of shales or economic conditions. Shale oils have different characteristics, depending on the source rock and method of retorting. They contain large quantities of olefinic hydrocarbons and more oxygen, nitrogen, and sulfur derivatives of hydrocarbons than most petroleums. Consequently, petroleum refining methods usually must be modified for shale oil. This is particularly true in catalytic processing. Hydrogenation, even under mild conditions, improves shale-oil refinability. Several byproducts may be obtained from both the retorting and refining steps.

Jan 1, 1964

By R. G. Gürtunca

The future of the United States (US) mining industry will be affected greatly by recent coal mining disasters. These have resulted in new legislation which will have an impact on mining economic costs as well safety and health of miners. This paper discusses the changes that new legislation and regulations are making to the industry and current research that is producing technologies to make mining safer and will likely impact the future of mining.

Jan 1, 2009

Prevention of coal-mine explosions depends largely upon thorough knowledge of the causes that initiate explosions. A review of coal-mine explosions in one geographical area when supplemented by nationwide data of similar nature, should serve as a guide for the adoption of measures for explosion prevention. Explosions in bituminous-coal mines of the United States during the 10 years ended December 31, 1932, ranked third in the causes of fatal accidents and constituted 16.1 percent of all fatal accidents in bituminous mines. Kentucky now ranks fourth in coal output in the coal-producing States of this country; a study of the coal-mine explosions in this state will be of definite interest locally among coal-mining people, as well as to those in the coal-mining industry who are concerned in preventing coal-mine explosions. This circular reviews gas and dust explosions in Kentucky coal mines to show their hazards, to point out the influence of certain factors in causing explosions, and to indicate the effectiveness of preventive measures.

Jan 1, 1934

By Richard Rittenhouse

This program was to develop a new base line system for automated continuous room and pillar type mining. The primary requirement estab¬lished for this machine is that the machine be capable of mining and bolting simultaneously. Additionally, this machine was to provide temporary and permanent roof control, have a productive - full - face semi-automatic mining system, leave a clean entry outby the machine, provide maximum operator protection, provide effective dust suppression and provide air scrubbing to restrict respirable dust to permissible levels. The machine has effectively demonstrated the ability to mine and bolt simultaneously. Additional above ground operation, testing, and time studies are recommended to further verify the machines abilities. Design improvements are recommended for future generation AES machines. These relate to marginal design areas such as side loading on vent duct lift cylinders, etc., that will not impair additional testing of the existing machine.

Jan 1, 1983

By Doris M. Hyde

In the past, mining has represented between 11% and 12% of the gross domestic product (GDP). In 1982, mining contributed over $150 million to the estimated $1.4 billion GDP.2 Overall economic growth for 1983 was projected at about 2%, primarily as a result of increased tourism. The inflation rate remained at or fell below the 1982 level of almost 4%. The Government continued its efforts to strengthen the industrial base by improving infrastructural systems and the establishment of a free trade zone. Laws against property ownership by foreigners or foreign-owned companies were strengthened, but the prohibition was softened to allow for close family inheritance. Otherwise, Government approval must be obtained to retain property acquired through inheritance, court order, mortgage, or other means. Special consideration was granted to foreign investors seeking to promote industries beneficial to the economy.

Jan 1, 1985

By W. F. M. GOSS

The locomotives in service on the railroads of this country consume more than one-fifth of the total coal production of the United States. The amount is so large that any small saving that can be made effective in locomotive practice at once becomes an important factor in conserving the fuel supply of the nation. For this reason the United States Geological Survey gave attEmtion to the special problems of combustion in locomotive boilers. It approached this task from several different directions. The facts presented herewith constitute one series of results. In the fall of 1906 the locomotive-testing laboratory of Purdue University, at Lafayette, Ind., entered on a series of tests, one purpose of which was to determine in precise terms the degree of efficiency with which a modern high-class American locomotive utilizes the heat energy of the fuel supplied to it. The general interest in the subject, the elaborate plans which had been formulated for conducting the work, and the substantial character of the support which had been pledged to maintain it justified the Geological Survey in aiding the investigation. a The cooperation of the Survey consisted in detailing experts to assist the regular staff of the laboratory in the chemical and calorific work of the tests. These experts, working under the general supervision of the director of the Purdue laboratory, became responsible for the sampling of smoke-box gases, of the fuel used, of the cinders caught in the front end, of the sparks discharged by the stack, and of the refuse caught in the ash pan. The gas analyses were made by them at the university laboratory. The analyses of all solid samples and the calorific tests of the fuels were made at the government fuel-testing plant at St. Louis. The representatives of the Survey were not concerned with other phases of the work.

Jan 1, 1911

By G. L. Anderson

The U.S. Bureau of Mines (USBM) has conducted research to improve the nondestructive testing (NDT) of wire hoist ropes. Losses in the diameter of a wire hoist rope are used as one criterion for judging when a rope should be replaced. Losses are determined by periodically measuring the rope diameter and comparing this measurement with the original measured diameter; when the diameter reaches a specified minimum at any point along its length, the rope must be retired. Generally, these measurements are made at randomly selected locations along the length of the rope, using a hand caliper. To provide more accurate measurements and to allow measurements to be taken continuously along the length of a hoist rope, an optical diameter-monitoring system was built for the USBM under contract. Continuous measurements are preferable because, when combined with continuous electro-magnetic NDT results, they can indicate whether losses in metallic cross-sectional area originate from external wear or internal wear and corrosion. Tests of the system showed that the instrument met specifications when measuring wire rope at low rope speeds but was inaccurate at speeds over about 30 m/min (100 ft/min). This report describes the prototype system, presents the results of the test program, and describes the capabilities of the system.

Jan 1, 2010

By W. N. Marchant

The Bureau of Mines improved removal of selenium from zinc smelter acidic gas scrubber effluent by using zinc dust to precipitate soluble selenium prior to lime neutralization. Lime neutralization alone decreased selenium in the waste water from, typically, 6 parts per million to 2 parts per million, whereas the use of zinc dust precipitant gave an effluent containing less than 0.1 part per million of selenium. The waste treatment operation first was developed on a laboratory scale and later was successfully tested at a smelter site on a 1-gallon-per-minute basis. During the research a simple and rapid means was developed for determining selenium in waste water; the technique enabled visual semiquantitative selenium determinations that later were confirmed quantitatively by X-ray fluorescence.

Jan 1, 1978

By H. Netuka, J. V. Horak, A. W. Khair

"A general review of major problems concerning mathematical modelling of roof bolting problem is given. A mathematical model (MM) of interactive set Bolt - Resin - Rock and its discretization based on the Finite Element Method (FEM) is developed to calculate numerically course of displacement, stress and strain fields in this set. This new MM enables to get also course of the normal and tangential components of contact stress vector, normal displacement and then mutual tangential slip at the bolt - resin and resin - rock interfaces, respectively.Behavior of system on all interfaces is modelled in the MM as a ""unilateral contact"" governed by so called non-classical boundary condition of Signorini's type including Coulomb's law of friction between resin and rock, and ""a given friction"" law between bolt and resin (see Duvaut, Lions (1972) for mathematical formulation).Numerical example and some values of resulting stresses are shown and remarks on necessary and sufficient conditions for solvability of the problem are also given.IntroductionAs is well known roof bolting has become the primary support system in almost all underground coal mines. But the ""theoretical"" design criteria for roof bolt patterns are rather problematic because: "" ... real mechanisms by which the roof bolts reinforce the immediate roof of underground coal mine entry are still relatively unknown"", see Peng (1986).The aim of this contribution is to present brief description of fundamentals of mathematical theory (see Hlavacek et al., 1988) which could be, according to our opinion and knowledge, very helpful for numerical modelling of a such type of problems. For the sake of brevity we restrict ourselves here to just one of the simplest possible problem: analysis of the behavior of interactive set composed by only single full - length - grouted bolt, resin (or cement) and suitable part of domain of a ""immediate"" neighborhood of bolt which should represent physical action of real rock material."

Dec 1, 1995

The 1965 Lignite Symposium, the fourth in a series and the third sponsored by the University of North Dakota and the Bureau of Mines, was held at Bismarck, N. Dak., on April 29-30, 1963. Them 7 symposia provide a forum for those interested in the technology and utilization of solid fuels, especially lignitic coals. As part of the meeting, a 200-mile field trip was taken including inspection of (1) the 200-megawatt, pulverized Lignite-fired Leland Olds plant of Basin Electric Power Cooperative, under construction near Stanton, N. Dak.; (2) the site of the Glenharold mine of the. Truax-Traer Goal Co., Division of Consolidation Coal Co., where a wheel excavator was being assembled; (3) the operating Beulah mine of Knife River Coal Mining Co., subsidiary of Montana-Dakota Utilities Co., near Beulah, N. Dak.; and (4) the 400-megawatt, hydro-electric Garrison Dam powerplant, near Garrison, N. Dak.

Jan 1, 1966

By R. V. Lundquist, H. Leitch

Sodium aluminate is the principal aluminum compound formed in the sinters prepared by the lime - soda sinter process for recovering aluminum from silicate source materials . The properties and characteristics of this compound were studied to improve the efficiency of the process . Crystalline sodium aluminate was prepared by sintering stoichiometric quantities of soda ash and calcined alumina for 1 hour at 1,250 ° C. The extent of aluminum extraction from sodium aluminate was determined in water and in solutions of NaOH and Na₂ CO3 . Nearly complete extraction of aluminum from sodium aluminate was achieved only in solutions containing free NaOH in excess of that supplied by the salt through hydrolysis . About 42.2 to 68.8 percent of the aluminum was extracted in water or in solutions of Na₂ CO . The precipitation of alumina trihydrate from sodium aluminate solutions was shown to be part of a continuous , reversible reaction according to the equation Al (OH ) A1 (OH )3 + OHThe reverse reaction dissolves alumina trihydrate in NaOH solutions to produce sodium aluminate . Approximate equilibrium concentrations were determined for the reaction at 30° , 50 ° , and 70 ° C. False apparent equilibrium conditions for the dissolution reaction appear when only a small excess of alumina trihydrate is present in the NaOH solutions . A large excess of alumina trihydrate must be present before the true equilibrium point is assured . The engineering significance of the data is summarized , showing controls that should be exercised for a successful and efficient process .

Jan 1, 1964

By J. R. Cobble

Dissolution of chalcopyrite with acidified ferric sulfate produces a sulfur layer on the unreacted chalcopyrite surface that interferes with further dissolution. The U.S. Bureau of Mines has developed a process to improve the leaching kinetics of these types of diffusion-controlled systems. The system features the Bureau-developed turbomill, an attrition grinder that scrubs the reaction product coating away from the unreacted mineral grains during leaching. The system can be operated continuously at any temperature up to the boiling point of the leaching agent. This method is a hydrometallurgical alternative to chalcopyrite smelter technology and eliminates sulfur dioxide emission problems with its associated costs. Batch testing at 900 C with the chalcopyrite-ferric sulfate system resulted in copper extraction exceeding 99 pct. At an optimal energy consumption of 1,520 kW· hjst, 95 pct of the copper was extracted. The pregnant liquor was clarified and tested for typical solvent-extraction recovery of the copper. Two-stage extraction and two-stage stripping recovered 96 pct of the copper in an electrolyte suitable for copper electrowinning.

Jan 1, 1993

By K. C. Dean

Discarded automobiles represent the greatest single resource of reusable metals, plastics, and rubber in the United States. This report presents results of Bureau of Mines research, conducted from 1965 to 1983, on separating and recovering useful materials from the scrapped hulks, using old and new metallurgical techniques combined with standard scrapyard methods. The Bureau determined the materials composition of three composite cars designated as circa 1960, mid-1970's, and early 1980's, and used these cars to study smokeless incineration and hand-sorting techniques. In studies on treating rejects from automobile shredders, the Bureau designed a process that included air classification, water elutriation, magnetic separation, handpicking, and heavy-medium separation, and also investigated cryogenics and liquation. Complete recovery of cop-per and other metals was economically made by hand and tool dismantling, leaching, or selective melting of starters and generators. Techniques are also discussed for plastic recovery and waste tire treatment.

Jan 1, 1985

By William W. Adams

A new record in accident prevention was made by the metal-mining a industry of the United States in 1938, as signalized by a lower fatality rate than in any previous year. The rate was less than half as high as in 1911, the earliest year for which figures are available. A good safety record was also established in the prevention of nonfatal injuries, as the injury rate was lower than in any other years except 1931 to 1935, a 5-year period notable for its unusually low injury rates. Employment was more limited in 1938 than in 1937, both in number of men employed and total number of man-hours worked. The number of workdays per man also was smaller than in 1937. Operating companies reported that 7,233 mines were active in 1938 or some part of the year and that the total number of men employed was 103,027. This figure represents the summation of the average number of men employed as reported by the companies, the average for each mine being that for the period during which the mine was active. The number of employees at all mines in 1938 was 15,402 less than in 1937. Reports covering all mines indicated a total of 188 million man-hours worked during the year, or 21 percent less than the nearly 240 million man-hours worked in 1937. In the performance of this work accidents occurred that resulted in the death of 156 employees and the injury of 1.2,722, each injured employee being disabled for more than the remainder of the clay on which he was hurt.. The fatality rate for 1938 was 0.83 per million man-hours worked, which was 9 percent more favorable than the rate of 0.91 for 1937. Nonfatal injuries occurred at the rate of 67.61 per million man-hours worked, an improvement of 10 percent compared with the injury rate of 75.37 for 1937.

Jan 1, 1941

By William W. Aljoe

This report summarizes the Bureau of Mines noise-control research program from 1972 to 1982. Each segment of the mining industry--under- ground coal, underground hardrock, surface mining, and processing plants--has different noise-control problems because of vast differences in working procedures, equipment, and workplace design. The Bureau has identified the most serious noise problems in each segment and has developed strategies for attacking these problems. This publication points out the need for noise control in the mining industry, discusses Federal regulations governing worker exposure to noise, and describes the Bureau's overall approach to mining noise- control research. It traces the history of noise overexposure in each segment of the mining industry and discusses the major noise sources. It provides detailed information on noise-control research efforts in the Bureau's major areas of emphasis, including the results of these efforts. Finally, the report discusses the Bureau's future role in research on mining noise control, emphasizing the need to expend more effort on long term in-house investigations into the noise problems that have been identified in past programs as the most serious ones.

Jan 1, 1985

By Ronald S. Conti

This paper describes technology and training that has been identified for underground emergency responders. Historically, underground mine rescue teams have only received training in the course of actual emergencies, or in simulated mine environments, usually on the surface, with placards to identify objects and hazards. Also, while U.S. Federal Regulations require all underground miners to walk escapeways and conduct fie drills every 90 days in a smoke-free environment, this does not fully prepare them for the conditions that will be encountered in real escape situations. Therefore, it is extremely important that miners are provided with adequate technology and that training simulations are conducted in a realistic manner. A series of mine rescue training and mine emergency response development (MERD) exercises, and in-mine smoke training was developed, conducted, and evaluated by state and company teams, and by National Institute For Occupational Safety and Health (NIOSH) personnel. The training exercises were held at NIOSH's Lake Lynn Laboratory (LLL) and operating mines during the past several years. This training resulted in improved technology and training for mine rescue teams, fire brigades, first responders, and miners in general. For example, existing technologies were identified to help responders during exploration and recovery operations. These included various chemical light shapes, strobe lights, light vests, and laser pointers to identify team members. Most of these devices may be used to mark underground areas and certain mine materials. Strobe lights were used for mapping out escapeways and lasers were used to negotiate travel through smoke. Thermal imaging systems allow rescue personnel to see in darkness and through dense smoke, and allows the user to easily locate missing or trapped personnel and heated areas. A hands-free communication system showed potential for enhanced communications between team members, the fresh air base, and command center. A new team lighted-lifeline allows for flexibility in movements of team members during routine tasks and allows them to easily find their fixed position on the lifeline. Of all the technology evaluated by underground personnel, laser lights and lifelines were most beneficial in leading personnel to safety and out of the mine in smoke-filled passageways. A positive-pressure inflatable escape device (IED)/airlock, was used to isolate the "hazardous" environment from fresh air and allow rescue team members to traverse through. An inflatable feed- tube partition that can rapidly block large openings such as underground passageways or tunnels and simultaneously provide a feed-tube for high-expansion foam generators was also deployed during the simulations. These technological advancements have improved the state of readiness for rescue personnel and have increased the chances of survival for all personnel escaping from underground emergencies.

By Henry M. Harris

A study was made by the Bureau of Mines to determine if shapes of oxide-glass compositions could be roll-formed at high temperatures, and to find the conditions required for adequate formability. A unit with directly connect' furnaces and heated rolls that allowed forming of most of the compositions developed. Glasses of the feldspar type were chemically unreactive with the alumina grains, and allowed the best roll forming. Optimum forming was attained at temperatures of 1,400° to 1,530° C, with compositions containing 30 or 40 percent feldspar and 60 or 70 percent alumina. Formability was better when compositions contained minus 325-mesh materials, rather than coarser or finer powders. In many cases, roll-formed shapes had physical properties equal to or better than the normally sintered shapes of the same composition.

Jan 1, 1967

By J. C. Barrett

Bureau of Mines research on the arc welding characteristics of titanium was initiated in 1948. Little was known about the art except that the easily contaminated metal required more protection from the atmosphere during welding than most other metals. Chambers were designed and built within which titanium could be welded with adequate inert gas protection. Welds were made and their properties studied, and prototype items were made successfully. This report, presenting a resume of the titanium arc-welding experiments undertaken by the Bureau of Mines, demonstrates that the process is successful if conducted under proper conditions and describes the welding of prototypes. INTRODUCTION The Bureau of Mines' first report on methods of joining titanium covered the subject of spot welding,4/ outlining the conditions necessary for producing spot welds in ductile titanium consolidated by powder metallurgy methods and describing the characteristics of such welds. This report embraces the field of fusion weld-ing of titanium and traces the development of suitable methods and equipment for producing such welds.

Jan 1, 1956