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By Oscar Lee, B. W. Gandrud, F. D. DeVaney

"IntroductionFlue dust which results from the smelting of ores containing appreciable quantities of fines is one of the troublesome products of iron blast-furnace practice. Gases issuing from the furnaces at a high velocity carry small particles of coke, ore and flux into dust-collecting chambers. These particles constitute the flue dust. Lasses of iron ore through the production of flue dust vary between wide limits in the different furnaces, and depend on a number of factors, such as size and design of furnace, amount of fines in the ore, the operating conditions and the blast pressure.Blast-furnace operators of the Birmingham district keenly realize this waste. The ores are comparatively low grade and require more fuel than is ordinarily used elsewhere. Hence the flue dust is low in iron content and high in coke. As a result it is not in suitable condition for direct sintering. In many other iron and steel centers direct sintering is a common practice. In the Birmingham district efforts have been made to prevent this loss by recharging the dust into the furnace, but, as might be expected, a material fine enough to be blown out once will very likely be carried over again.In general, the flue-dust losses in this district will average 250 pounds per ton of pig iron produced, but at times the losses at different furnaces are substantially higher or lower than this figure. On the basis of the present rate of pig-iron production, the annual loss of flue dust exceeds 300,000 tons. The iron content of the dust probably averages 25 per cent, therefore about 75,000 tons of iron is wasted yearly, or about 3 per cent of the iron mined is lost in flue dust."

Jul 1, 1926

By David P. Lindroth

The objective of this research by the Bureau of Mines was to determine the technical feasibility and associated pilot data for drying minus 1/4-in coal with microwave energy at a frequency of 2.45 GHz. The drying data were obtained experimentally on three coal types: bituminous, subbituminous, and lignite. The experiments were performed with a custom-designed conveyorized microwave oven having a continuous power capability of 12 kW. Drying efficiencies near the theoretical maximum of 1.54 kg of water per kilowatt hour of energy input were achieved for two coals and two sizes; overall drying efficiencies averaged 77 pct.

Jan 1, 1986

By R. T. Johansen

A gradual decrease in injection rates commonly occurs as a water-flooding project becomes older. This decrease can be attributed to changes in reservoir conditions, such as swelling of clay minerals, fillup, or gradual plugging of the sand face. However, a rapid decrease in the rate of injection indicates abnormal behavior and is cause for alarm. Extreme plugging conditions can completely stop injections into a formation. Such behavior in wells was the main concern of the tests described in this report. An accepted method of alleviating this condition is by backflowing input wells - closing the supply lines to the wells and allowing the reservoir pressure to force water back into the wellbore and to the surface. If backflowing is not successful, a string of smaller diameter pipe sometimes is run inside the casing, and the sand face is flushed with a waterspray. More drastic treatment is to inject acid into the wellbore to dissolve extraneous matter, or even part of the reservoir material, in an attempt to restore the permeability of the sand immediately around the wellbore. Any of these procedures can he coordinated with bailing and swabbing of the well for cleanout purposes.

Jan 1, 1957

By James Westfield

A brief résumé follows of recent activities of the Division of Coal-Mine Inspection that have had a favorable effect on health, safety, and the reduction of injuries at coal mines: 1. The Federal Mine Safety Code for Bituminous Coal and Lignite Mines of the United States was issued originally by the Director of the Bureau of Mines on July 24, 1946, after consulting with management and labor representatives of the coal-mining industry. The code has been used by Federal coal-mine inspectors while inspecting bituminous-coal and lignite mines as a basis for determining the existence of unhealthful and unsafe conditions and practices in these mines. A revised code was issued by the Secretary of the Interior on October 8, 1953, after further consultations with representatives of management and mine workers and was incorporated by reference in the 1952 and subsequent bituminous-coal wage agreements. The agreement of May 29, 1946, between the Secretary of the Interior, acting as Coal Mines Administrator under authority of Executive Order 9728, and the United Mine Workers of America, covering bituminous-coal and lignite mines in Government possession, charged Federal coal-mine inspectors with the responsibility of making periodic investigations of the mines and reporting to the Coal Mines Administrator any violations of the Federal Mine Safety Code. Federal coal-mine inspectors also had temporary authority to close mines found to be imminently dangerous, but such authority (under Executive Order 9728) was removed on June 30, 1947, when Government control of the mines was terminated.

Jan 1, 1958

By Lowell B. Moon

Concern over possible wartime shortages finally resulted in passage of the Strategic Materials Act in 1939. As authorized by one section of this legislation, the Bureau of Mines proceeded to investigate deposits of seven strategic minerals with the objective of developing tonnages of low-grade material that could be mined in an emergency. During the war, the size of the program and the number of strategic minerals were increased, and the objective was the more immediate one of aiding production. Since the war, the size of the program has been reduced, but the number of minerals on the strategic list continues to be large. The objective has returned to that of 1939. In the course of the program, more than 10,000 examinations were made and about 1,300 projects were run on deposits of 33 different commodities. A considerable contribution to war production was made in six of the commodities investigated, and a minor contribution was made in twelve others. Substantial reserves have been indicated in 19 minerals. Private interest is currently active in some of the deposits developed in 14 commodities.

Jan 1, 1950

By Ralph H. Whaite

To assist the anthracite industry obtain technical data on pneumatic packing, the Federal Bureau of Mines imported a pneumatic packing machine from Germany and installed it in a mine of a cooperating company in the Northern anthracite field of Pennsylvania. This report covers the second in a series of experiments in applying pneumatic packing for controlling strata movement (subsidence) above mine workings in the Pennsylvania anthracite region. The first experiment2/ was begun in January 1950, in a section of the mine where about 50 percent of the original coal remained in the form of pillars; since the company did not plan to mine the pillars in this particular area, pneumatic packing of the chamber voids was done for test purposes only. During this initial test the machine was operated on 204 shifts, and 652,400 cubic feet of breaker refuse material (22,834 tons) was packed into the voids of 16 chambers. The work was completed in December 1951.

Jan 1, 1956

This report, the fourth in an annual series, outlines recent trends and developments in the minerals industry. Discussed are new methods, equipment, techniques, and systems used to more effectively extract and process mineral products. Environmental considerations, health and safety standards, price controls, inflation, material shortages, and more dependence on foreign imports were problems faced by the minerals industry. Although productivity increased for most mineral commodities, the annual rate of increase has slowed in recent years, indicating a maturing technological situation. Growing concern for energy resulted in increased interest and research in alternative fuel sources. The primary concerns of metallurgists were pollution control and improved efficiency and performance of metallurgical processes, especially for reduction of energy consumption.

Jan 1, 1974

By R. L. Soderberg

Large open stopes mined by vertical crater retreat or sublevel s are sometimes backfilled with uncemented sand to support the stope walls and alleviate rock bursts. The failure of bulkheads in two different mines prompted a research project at the Bureau of Mines to prevent a recurrence of these failures. A series of laboratory tests with drains and sand filters was conducted to measure the bulk-head pressures when adequate drainage was maintained. Results showed that bulkhead pressure was reduced to near zero while drains were in operation, as compared to full hydrostatic pressure when drains were blocked or drainage was restricted. A relatively simple, free-draining bulkhead was shown to be adequate.

Jan 1, 1985

By A. R. Rule

A flotation process was developed by the Bureau of Mines for separation of carbonate and phosphate minerals occurring in unaltered phosphate ores of the Phosphoria formation. The process involves depression of phosphate minerals with fluosilicic acid and flotation of carbonate minerals with fatty acid emulsions. In individual laboratory tests, selective removal of carbonates was achieved with phosphate recoveries ranging from 60 to 80 pct P205. In continuous-circuit testing, sizing and separate treatment of coarse and fine fractions was necessary to achieve 65-pct P205 recovery. Concentrate grade ranged from 26 to 33 pct P205. The flotation tailings containing primarily carbonate and phosphate minerals is a potential fertilizer material. When reacted with H3P04, concentrated superphosphate containing approximately 40 pct available P205 was obtained.

Jan 1, 1974

By Mark R. Pettitt

The results of an extensive research and development program to reduce the noise generated during coal cutting are presented. The characteristics and magnitude of continuous miner coal cutting noise sources are defined. This work consisted of development of a simulated coal ,cam to facilitate above-ground coal cutting tests, noise measurements in a reverberant acoustic chamber during simulated mining operations of a continuous miner (cutting the simulated coal scam), and noise measurements in an underground coal mine during continuous miner operation. In-mine and laboratory test results were in excellent agreement for both A-weighted overall levels as well as A-weighted one-third octave band spectra. Methods to reduce coal cutting noise are presented. These methods take full advantage of the dynamic characteristics of the forces generated during coal cutting. Dynamic cutting force isolation was shown to be a very effective technique. Finally, a continuous miner was equipped with a cutter head that incorporated (among other design factors) cutting force isolation. Successful, lung term, in-mine use of the cutter head demonstrated coal cutting noise at the operator's station of less than 90 dBA and 50% coal, 50% rock cutting of less than 93 dBA.

Jan 1, 1985

By Pamela J. Watson

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

Jan 1, 2010

By Eugene H. Skinner

The U.S. Bureau of Mines conducted experiments on the use of lightweight concrete in the density range of 100 Ib/ft3 for liners in underground mines. Three test sections were completed: a monolithic, portal-type structure with integral walls and arch constructed aboveground; an underground test section constructed in a mine drift using plywood forms; and a second section constructed in a drift using an air-supported formwork. The lightweight concrete in the two underground test sections was placed using piston pumps and a slickline. Fiber reinforcement was added to the concrete in the mine sections without any apparent problems with either pumping or placement of the concrete. In another experiment, the Bureau and Hecla Mining Co., Mullan, rD, used lightweight concrete in the density range of 25 Iblfe to replace timber blocking in a raise preparation structure. Other experiments are described in which low-density, lightweight concrete blocks were produced for mine ventilation doors, stoppings, and barricades. Other mine uses reviewed include pillars and collapsing beams. An advantage of low-density concrete is that it will display up to 50% deformation at a constant yield stress. These hlllovative concepts in deformable concrete lining systems will aid mine operators by decreasing capital and maintenance costs, increasing the available space in underground haulageways, and providing productivity gains and improved resource recovery in the soft, caving, squeezing, or bursting grollnu conditions often found in deep mines.

Jan 1, 1989

By N. H. Coates

A small, special-purpose centrifugal compressor was developed to circulate 60 pounds per hour of helium at 1,000° F and 250 psig because standard, commercial units were not available. Performance characteristics of this compressor were determined at helium flows of 2,000 to 18,000 std cu ft per hour, pressures of 100 to 250 psig, and temperatures of 100° to 1,000° F. This range is 2 to 90 actual cu ft per minute. Several graphs show the adiabatic head developed by the compressor over this wide flow range at various combinations of temperature and pressure. A compressor performance map relates pressure ratio to mass flow, temperature, pressure, and speed. This map can be used to accurately predict compressor performance factors within the range of operating conditions covered by the experiments.

Jan 1, 1963

By Albert L. Toenges, Theodore R. Jolley

"INTRODUCTION The construction of frame houses (fig. 1) in recent years instead of the conventional sod hut (igloo) (fig. 2) by the Eskimos in the villages along the Arctic Ocean has increased the demand for fuel in these villages. The frame houses, which are not insulated against extreme cold and are difficult to heat, are equipped with Goal stoves. The well-insulated sod huts were heated comfortably with whale-oil stoves. In some years whaling is Door, consequently there is a demand for solid fuel.The Eskimo villages usually are on the sand spits at the mouths of rivers and points of land near the best fishing and hunting grounds. These narrow necks of land usually are sand bars that are not underlain with coal, and coal must be transported to the villages. Lack of development of coal deposits in the Arctic has made it necessary to import coal from the States, generally from 'Washington, to supply these villages. This coal is imported by boat and is received once a year. Its cost is, high, and development of coal deposits in the Arctic to supply these native villages should result in a considerable saving to the Government-operated schools and hospitals as well as to the natives.Early traders attempted to establish coaling stations in the Arctic, and the Eskimos generally know where the coal deposits are situated. A. reconnaissance of a number of deposits in the Arctic was made in the summer of 1946 by engineers of the Coal Division, Fuels and Explosives Branch, Bureau of Mines, and this report describes the areas investigated and suggests plans for the development of some of these deposits."

Dec 1, 1947

By Albert A. Munsch

The Munsch National First-Aid Instructors Association had its inception during the teaching of a Federal Bureau of Mines first-aid instructors' class at McPherson, Kans., under a cooperative plan of first-aid training. Upon completion of- the course on July 1, 1938 members of the class organized the charter chapter of the association under the name of McPherson (Kans.) District Charter Chapter No. 1. On July 1, 1941, 3 years after the founding of the association, there were 15 chapters in the national council -7 in Kansas, 3 in Oklahoma, 2 in Texas, 2 in New Mexico, and 1 in Arkansas. Although the pioneer work of the association was done in the petroleum industry, the plan will be of even greater benefit to a district in which there are various types of plants, mince, and operations of the mineral and allied industries. ACKNOWLEDGMENTS The writer appreciates the cooperation and assistance of the following persons: S. P. Redfearn, safety engineer, Globe Oil & Refining Co. and affiliated companies, Wichita, Kans., and H. (Chief) Moore supervisor of safety meetings, Shell Oil Co., Inc., McPherson, Kans., for their untiring efforts and enthusiasm in organizing an- attending the first class, organizing three other classes, and helping to plan the work of the association

Jan 1, 1942

By H. E. Peterson, W. L. Anderson

"INTRODUCTION The great demand for tungsten incident to the war has led to the exploration of a large number of low-grade tungsten deposits. To properly evaluate the low-grade deposits it is essential to have available a dependable method of analysis applicable to all types of low-grade tungsten ores. Results reported on the tungsten content of the ores have often varied quite widely and have led to confusion. The Bureau of Mines has been requested by Government lending agencies and by companies interested in the production of tungsten to publish a general method for the determination of tungsten in low-grade ores. To meet this need, the Bureau of Mines is herein submitting two methods for analysis that have been proved on a large number of tungsten-bearing ores various types in the Bureau of Mines laboratory in Salt Lake City. Also, a third method was developed that requires no cinchonine and has proved to be applicable on most tungsten ores. The cinchonine method is the generally accepted for analysis of tungsten ores. Very reliable results can be obtained by this method if certain precautions are taken, as outlined in this report."

May 1, 1943

By E. K. Stanek

This report contains results of two major efforts related to electrical transients on mine electrical power systems. The first area concerns the use of digital computers to model mine electrical power systems and predict transients or duplicate field recordings of transients. Two existing general purpose circuit analysis programs were used. The first was the TRW Engineering System Simulator or TESS. The second was Electronic Circuit Analysis Program or ECAP. TESS proved to be superior to ECAP in several important characteristics, including system size limitations and modeling nonlinear elements. The second major topic covered in this report is the evaluation of commercially available surge suppression devices. These devices were found to be quite acceptable and guidelines for the selection and placement of surge suppressors were included. The final important item is a listing of the worst-case transients, from a design point of view, for ac and de utilization systems and ac distribution systems.

Jan 1, 1979

By S. L. Windes

This report presents physical and petrographic properties of approximately 60 types of rock from operating mines or mineral-investigation projects and supplements Repot of Investigations 4459, Physical Properties of Mine Rock (hereinafter referred to as Part I). The physical properties evaluated include the following: Apparent specific gravity Apparent porosity Compressive strength Flexural strength (modulus of rupture) Impact touchiness Abrasion hardness Scleroscope hardness Modulus of elasticity (Yourg?s modulus) Modulus of rigidity Specific damping capacity Longitudinal bar velocity

Jan 1, 1950

By J. A. Organiscak

Quartz dust is one of the most significant ongoing health concerns in coal mining today. Since the early 1980's, the U.S. Bureau of Mines has conducted numerous studies in underground and surface coal mines to identify the sources of quartz dust and its fundamental characteristics. This report presents data and conclusions obtained from these studies. The two most significant quartz dust sources were found to be the continuous miner excavating rock and the highwall drill operating in a rock overburden. The percentage of quartz was found to be higher in the smaller size fractions of dust when significant amounts of rock were mined by the continuous miner. Another factor theorized to affect quartz dust generation and size characteristics is the morphology of the quartz-bearing rock. Several laboratory studies were conducted to investigate capture efficiency of water spray technology and flooded-bed scrubbers with respect to the particle size of the dust. Water sprays and flooded-bed scrubbers were both found to be less efficient on smaller dust particles, and the scrubber was particularly less efficient on quartz dust. These results indicate that quartz control technology should be directed at controlling smaller sized dust particles.

Jan 1, 1990

By C. C. Popoff

The Dunkleberg district is in the Flint Creek Range of the northern Rocky Mountains, about 45 miles northwest of Butte, Mont. Silver - lead and zinc mineralization occurs over an area 4 miles long from north to south and 1 to 2 miles wide from west to east. Ore in appreciable quantity has been produced, mostly from the Forest Rose group of mines in the southern part of the district. The Forest Rose mine was the largest producer of lead and the Wasa mine, a mile farther south, the main producer of zinc. The total output of ore from these properties during World War II was 113,000 tons, or 98.2 percent of the total recorded production of the district. The Wasa mine was examined by a Bureau of Mines engineer2/ in 1944. Subsequent investigations during 1946, 1947, and 1948 included trenching and drilling Fn the Wasa area and examination of the Forest Rose and other mines.

Jan 1, 1953