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By J. B. Gayle

A 1/2-ton experimental coke oven was installed ac the Bureau of Mines Southern Experiment Station, Tuscaloosa, Ala., in 1948. Designated as the Tuscaloosa oven, this unit features a 17-inch carbonizing chamber, globar heating elements, and silica-brick walls designed to simulate as closely as possible the carbonizing conditions for commercial slot-type ovens. Because of the small force exerted on the oven walls in most tests conducted to date (probably owing to the practice of charging coals and blends at a moisture content approximating that normal to commercial plants operating in this district), little information has been obtained about expansion properties. Two sole-heated ovens have therefore been constructed and used as supplementary equipment for determining the expansion properties of coals tested in the Tuscaloosa oven. The reasons for constructing the Tuscaloosa oven, the details of design, the operating, characteristics of the oven and the reproducibility of results have been discussed in previous publications. 3 4 5/ The present report deals with the effects of substituting various high- and low-volatile coals for components of a selected base blend carbonized under conditions similar to those normally used for producing foundry coke. Results of tests of 11 coals and 14 blends indicate that several blends tested rave cokes having physical properties very similar to those produced from the reference blend.

Jan 1, 1957

By Catherine C. Kilgore

The Bureau of Mines investigated the availability of manganese from known domestic occurrences. Eight of these deposits were found to have demonstrated resources totaling 420 million metric tons with an average grade of 10 percent contained manganese. They were found to be submarginally subeconomic. Economic evaluations of the eight deposits resulted in incentive prices ranging from $8 to almost $35 per long ton unit (22.4 pounds) of contained manganese. Comparing these prices with the current market value of $1.70 per long ton unit of manganese clearly illustrates the submarginal nature of the domestic ores analyzed. These domestic resources would probably not be developed except in the case of an extreme national emergency. Production from the eight deposits would take 3 to 6 years to develop, and the final product would be manganese ore concentrate, which could be used in the production of ferromanganese. If preproduction development began in 1981, annual production would peak in 1987 with 900,000 metric tons of recoverable manganese. Thereafter, production would see a steady decline unless additional resources were located or technologic improvements were made to allow processing of lower grade material, or unless mining and processing of ocean manganese nodules began to take place.

Jan 1, 1982

By Wilbur I. Duvall, Thomas C. Atchison, David E. Fogelson

The breakage of rock by explosives depends largely on the ability of an explosive to transfer its stored potential energy to the rock as strain en- ergy. Therefore, the relative rock-breaking abilities of explosives can be determined indirectly by determining the relative amounts of strain energy transferred to the rock at the time of detonation. This report presents experimental data on the strain energy contained in explosion-generated strain pulses in a granite gneiss. Six explosives were tested. The scaled total radial strain energy E/W flowing outward through a spherical shell of scaled radius R/W1/3 surrounding the point of detonation was found to follow an exponential decay propagation law of the form Analysis of the data showed that the intercept parameter H depended upon the type of explosive used but that the absorption coefficient B was practi- cally independent of the type of explosive. Comparison of the intercept pa- rameter H and the calculated energy of the explosive showed that the percent- age of explosive energy transferred to the rock increased linearly as the ratio of the characteristic impedance (product of density and propagation velocity) of the explosive to that of the rock increased toward unity. From 5 to 9 percent of the calculated total energy released by the explosive was transferred to the rock as radial strain energy.

Dec 1, 1959

By John A. Johnson

Tests ere conducted at the Mount Weather testing adit of the 57 Bureau of Mines on the effectiveness of spraying water along the outside of the drill steel as compared with standard wet-drilling practice. The spray equipment used in the tests was designed primarily for the control, in quarries, of dust from dry drilling with solid type drill steel. Equipment Spray equipment is made in sizes to fit different drill steel but is alike in design, the only difference being in the diameter of the ring and the number of spray holes. The device is mace of cast steel and has a coating of Stellite on the inside edge that comes in contact with the drill steel. It looks like a garden spray, except that the spray holes point in only one direction.

Jan 1, 1939

By J. M. Singer

Flame propagation of lower limit hybrid coal dust-methane-air mixtures in vertical and horizontal flame ducts of 15.2 cm id and 1.8 m length has been investigated to provide information bearing on safety in mines. Fuel concentrations at lower limits of flame propagation and equivalences of coal dust and methane are much higher for continuing flame propagation than for short-span flame propagation in the vicinity of an "overdriving" ignition source. As the energy of the ignition source was increased, the flame speed and the distance of flame propagation from the ignition source increased, whereas the total fuel concentration at the lower limit decreased.

Jan 1, 1968

By Edward D. Thimons

Because of the high number of accidental methane gas ignitions in metal and nonmetal mines, the Bureau of Mines searched for a simple guideline that would allow mine personnel to evaluate the methane hazard in a given mine. Air samples were collected by the Bureau in 53 metal and nonmetal mines and analyzed for trace evidence of methane gas. Samples were collected in the returns and at the working faces. Those mines classified as gassy by the Mine Safety and Health Administration had a significantly higher average methane concentration than those classified as nongassy. Of the 9 gassy mines sampled, 7 had methane concentrations above 100 ppm, whereas only 1 of the 44 nongassy mines had a concentration above 100 ppm. The 100-ppm concentration may be used as a simple and convenient guideline for forecasting the methane hazard in a mine, whether or not the mine is classified as gassy. There was no consistent correlation between commodity mined and methane concentration, nor was there a correlation between mine depth and methane concentration. Neither of these factors can be considered a guideline for predicting methane hazards.

Jan 1, 1979

By R. D. Leitch, W. P. Yant

"In the course of another investigation4 during 1926 and 1927, samples of water collected from a few abandoned coal mines indicated that their drainage was usually lower in acidity than water from active mines in the same locality. In order to determine whether this condition might have a bearing on the advisability of sealing abandoned mines, a number of such mines were visited, samples of drainage were collected, and as much information- as possible was obtained from officials of the mining companies and older residents of the district. The results of this work are the basis of the present report.The authors are indebted to E. W. Robertson, F. F. Spowart, J. H. Nagle, and W. D. Adams of the Northwest Mining & Exchange Co.; E. M. Fasset, Fred Lane, Wm. Humphreys, and Dr. T. A. Hutchison of Brockway, Pa.; C. W. .Faulk of the Shawmut Mining Co.; James Hau of Kersey, Pa., and to others for information received; and to Dr. R. R. Sayers of the Bureau of Mines, under whose direction the work was conducted.The Lower Kittanning is the most important bed in the locality studied. A great many of the abandoned mines examined are in this bed, and nearly all of the present active ones are. The Upper Freeport bed is also mined to some extent, and a number of the abandoned mines formerly worked this bed. As only three active mines are now (1927) working the Upper Freeport, the comparison of acidities is necessarily limited. Of these three, one had been idle since 1922 until shortly before it was sampled.The location of most of the mines was already known from previous work, but some of them had to be located by following up streams known to contain acid waters. A sample of the- outflow was collected in self-sealing bottles known as ""citrate bottles"" for the determination of dissolved oxygen by the Winkler method.5 Another sample was taken for the determination of acidity according to standard methods of water analysis.6 Ferrous iron was determined at the mine or very soon after taking the sample by titrating with a standard solution of potassium permanganate in acid solution. The hydrogen-ion value was determined by a standard double-wedge comparator.7From the total acidity values in each sample, which are the most important values, the total iron was calculated on the assumption that acidity as sulphuric acid was due to dissolved ferrous sulphate. This assumption is commonly made for mine waters, but is inaccurate to the extent that free acid is already present, and some of the iron is present as ferric, rather than ferrous, sulphate. The amount of ferrous sulphate may be a rough measure of the extent to which oxygen is lacking within the mine. The permanganate titrations just mentioned showed what part of this total iron was in combination as ferrous sulphate, and the difference .was assumed to be that in combination as ferric sulphate, after correcting for the amount of free acid already formed as shown by the titration values."

Oct 1, 1928

By John A. Johnson

[Tests were conducted at the Mount Weather testing adit of the Bureau of Mines4/ on the effectiveness of spraying water along the outside of the drill steel as compared with standard wet-drilling practice. The spray equipment used in the tests was designed primarily for the control, in quarries, of dust from dry drilling with solid type drill steel. EQUIPMENT Spray equipment is made in sizes to fit different drill steel but is alike in design, the only difference being in the diameter of the ring and the number of spray holes. The device is made of cast steel and has a coating of Stellite on the inside edge that comes in contact with the drill steel. It looks like a garden spray, except that the spray holes point in only one direction.]

Jan 1, 1939

In 2007, a total of 278 metal mining operations reported employment to the Mine Safety and Health Administration (MSHA).1 Metal mines were the smallest mining commodity sector, comprising 1.9% of all mining operations. ? Gold mines comprised 44.6% (n=124) of all metal mining operations. Other common types of metal mines were iron ore (n=36; 12.9%) and copper ore (n=35; 12.6%). ? Nevada had the largest number of metal mines (n=45; 16.2%), followed by Alaska (n=28; 10.1%).

Aug 1, 2009

By C. W. Owings

"PURPOSE OF REPORTThe safety and efficacy of permissible storage—battery gathering locomotives are becoming recognized more and more in coal mines. The great mobility of this type of haulage equipment is due to the fact that no trolley wire and bonding of rails are needed; hence wherever there is track and adequate ventilation to dilute properly any dangerous gases, the storage—battery gathering locomotive may go. As coal near the outcrop or the surface is mined out, coal farther from the outcrop or deeper in the ground must be mined, and gassiness of the coal bed often increases under these conditions. The use of electrical equip¬ment capable of giving off arcs or sparks while operating near or at the coal faces constitutes a serious explosion hazard. Often, it is uneconomical or impracticable to use animal haulage, and locomotives must be employed. The operator should consider the safest and most economical unit; permissible equipment is the answer to this problem, and storage—battery locomotives are the only permissible electric haulage units.A comparison of permissible storage—battery locomotives with cable—reel locomotives of the latest enclosed ""explosion—tested"" type has been made at the Keystone No. 1 mine of the Houston Collieries Co., at Keys one, W. Va. The information and data contained in this publication were obtained by the writer during an inspection of haulage at this mine.ACKNOWLEDGMENTSThe writer is indebted to P. C. Thomas, vice president and general manager, the Koppers Coal Co., operator of the Keystone mines, who granted permission for making the study. W. A. Wilson, general superintendent, Houston Collieries Co., arranged for the investigation and for obtaining the data. C. E. Zuspan, chief electrical inspector, and J. C. Newman, division electrical inspector, accompanied the writer underground and assisted materially in obtaining information and data upon the haulage methods and performance of the locomotives. The assistance or general mine Foreman Pierman and of mine foreman White is gratefully acknowledged."

Aug 1, 1931

By Carl Belser

In 1925 the Park Utah Consolidated Mines Co., after several years of experimental work, installed a system for signalling from cages which has been operating efficiently and with low upkeep costs for the post 19 years. The system was adopted for a large western metal mine but was later abandoned be arse of the constantly shifting shaft alinement. Recently the system has been studied and probably will be put into service at two other large mines. One of the principal reasons wry the system has not boon adopted more widely has been the lack of adequate details both as to the desirability of having such a system and as to its construction and operation. Previous signaling, systems contained undesirable features, such as charged bare wires extending the full length of the shaft. Under the direction of O. N. Friendly, then general superintendent of the Judge Mining & Smelting Co., the present system, entailing the use of a samll current at low voltage, was gradually developed. Many of the refinements in the system wore contributed by Leonard Wilson, consulting electrical engineer, Salt Lake City, Utah.

Jan 1, 1945

By Clinton C. Knox

During the latter part of 1943, a magnetometric survey was conducted by the Geophysical Division of the Bureau of Mines at the Mahopac magnetite mine, Putnam County, N. Y., in an endeavor to locate a segment of the ore body that reports state was cut off by a fault. The Mahopac mine was abandoned about 1895 after producing nearly 1,000,000 tons of high-grade magnetite iron ore. The results of the investigation indicate the termination of the ore body by "pinching", or a displacement of such magnitude as to place any extension at a considerable distance from the original are body. This report describes the work done on the project and presents the data obtained.

Jan 1, 1948

By R. C. Buehl

An experimental iron blast furnace of 3-foot-diameter hearth, producing about 12 tons of metal per day, was operated for 2 weeks with various proportions of anthracite replacing a corresponding amount of coke. The furnace operated well with anthracite in amounts up to 40 percent of the total fuel and produced metal of uniformly low sulfur and normal silicon contents. An increase to 50 percent anthracite during two attempts resulted in poor operation and the charge hung in the s haft of the furnace. INTRODUCTION Anthracite production in Pennsylvania decreased from 84,400,000 net tons in 1926 to 40,600,000 net tons in 1952, and there was a further decline in 1953 to 30,900,000 net tons. Employment in the anthracite industry dropped from 165,000 men working an average of 244 days per year in 1926 to 57,900 working an average of 163 days per year in 1953,3/ which has naturally resulted in considerable unemployment in the region. The industry is actively engaged in promoting new uses for anthracite to increase the demand and thus improve economic conditions in the region. One possibility is the use of anthracite to replace part of the coke for smelting iron ore in blast furnaces. The tests in this report were made to determine whether this use of anthracite would be feasible.

Jan 1, 1955

By Shirley F. Colby

A continued rise in construction activity in 1941 forecasts further increases in the demand for building materials of mineral origin, Recent studies by the Bureau of Mines, United States Department of the Interior, reveal that sales of mine and quarry products and their derivatives as a class have followed the long-term trend of construction activity in the past and are benefiting now by the upswing in all types of building. At present most building materials of mineral origin are holding their own in the competitive arena. A few are slipping behind, but others have forged fax ahead. Prominent among those that have surpassed general construction activity since 1925 are sand, gravel, and crushed stone (used in concrete and road metal and railroad ballast) and cement. Both building stone and roofing slate have followed the building curve closely, although in the last few years sales of roofing slate have risen above the curve and sales of building stone have dropped below it. Clay products and building lime, on the other hand, have lagged behind the general procession. Gypsum sales likewise dropped behind, but during the last few years, this industry, thanks to the wider acceptance of its newer products, has staged a marked recovery so that it now stands in about the same relation to total construction activity as it did is 1927-25.

Jan 1, 1941

By Philip C. Good

Unweathered low-grade calcareous phosphate rock of about 20 percent P205 grade was beneficiated by a procedure in which contained carbonates were decomposed by calcination at about 1,000° C. On quenching the hot calcined rock in water, major impurities passed into a slime phase which was mechanically separated from a coarser concentrate fraction. Phosphate rock of two major types was beneficiated in batch-scale studies yielding concentrates containing 31.3 to 38.5 percent P205 at recoveries ranging from 54.8 to 86.0 percent. The samples were from two major deposits in India. Processing information gained was utilized in extending the work to a continuous-flow system, processing phosphate rock at rates up to 157 kilograms per hour. Superphosphate exceeding 16 percent water-soluble P205 was prepared from concentrate derived from continuous-flow processing.

Jan 1, 1976

By Jerry E. Olson

In 1985 the U.S. Bureau of Mines conducted a mineral survey of 68,458 acres of the Clan Alpine Mountains Wilderness Study Area (NV-030-102) which covers 196,128 acres in Churchill County, NV. Most of the area studied is underlain by Tertiary volcanic rocks. In the northeast corner of the study area, an upthrown block of Triassic sedimentary rocks partially extends into the area. The study area is probably part of a large eroded caldera. No major mines or active claims are within the study area. Field investigations included examination of workings in Starr Canyon, historical and recent mining activity near the mouth of Florence Canyon, other mining claims, and anomalous zones delineated by data from Great Basin GEM Joint Venture studies. No mineral resources were identified, but sample results indicate one significant mineralized zone situated along a northwest trend between the head of Starr Canyon and the head of Cherry Creek may contain precious metal resources. Further investigation of this zone is warranted.

Jan 1, 1987

By A. Z. Dimitroff

An improvised rock-dust disseminator, consisting of a 10-gallon galvanized metal milk can that dispenses rock dust in return air currents by the injection of compressed air has reduced the float dust explosion hazards at the Koehler coal mine, Koehler, N. Mex.

Jan 1, 1965

By Wallace W. Roepke

The Bureau of Mines has a well-established health and safety research effort directed to fundamental studies of the mine cutting system. This report describes the ignition danger of using cutting bits with flat wear area on still-intact carbide inserts.

Jan 1, 1983

By John H. Soulé

"INTRODUCTION Spodumene and lepidolite were shipped from the Harding pegmatite deposit, Taos County, N. Mex., in the period from 1930 to 1930. Tantalum minerals were noted as early as 1924 and described in 1931 3/ but no tantalum ore was shipped until 1942. The deposit was mapped and studied by geologists of the Federal Geological Survey and engineers of the Bureau of Mines late in 1942 and early in 1943, and a Bureau of Minus exploratory project was carried out in 1943. 4/ Thu following report presents the results of that project.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Minos has as its primary objective the more effective utilization of our mineral resources to the end that they make the greates possible contribution to national security and economy. It i the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lovell B. Moor, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallugiical 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."

Dec 1, 1946

By S. H. Ash

As part of the work done at the Washington coal mines during the year 1929 , a study was made of the safety practices in and about the mines . Inasmuch as electrical blasting has made considerable headway it is interesting to note the manner in which it is done and the reasons why it was discarded at some of the mines . Blasting is done at the mines in the State by means of capped fuse , electric blasting " caps , " and in some instances by electric delay detonators . Black blasting powder with fuse is used at most of the open- light mines . The use of squibs was discontinued several years ago because the coal operators , without exception , recognized the dangers incidental to their use . Permissible explosive and dynamite are also used at some of the open- light mines . With the exception of some rock work and the driving of level work in gangways and air courses the explosive is detonated by means of capped fuse .

Apr 1, 1930