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By G. L. Oldright

In the first Report of Investigations of the present series?(No. 4562) the usual course of progress ill reducing the minerals of low-grade ores to their valuable metallic components had been noted as advancing along two lines to concentrate a usually diminishing percentage of these minerals to a smaller bulk of richer product, and then to smelt the smaller bulk more cheaply per pound of metal produced. Fundamental properties of lead compounds made it difficult to treat much richer lead products than are treated at present in several steps of conventional lead smelting, unless ?marked modifications were made. No limits to the richness of the feed itself' were set by the ore (Scotch) hearth; on the contrary, the richer the feed, the better the results given by the hearth. The natural field of operation of the hearth, as determined by the ores available, was seen to lie in the Central United States, with their lead concentrates containing negligible quantities of precious metals and. with few ores of such metals available for use as fluxes. It was noted) however, that even in its chosen field, the Scotch hearth, or "ore" hearths developed from them, was not always used; the usual smelting practice was followed, at times, of sintering followed by blast-furnace smelting for even rich ores.

Jan 1, 1949

By Eugene O. Binyon

"Belt and shaker conveyors, used singly or as combined units, have for many years been an integral part of many coal-mine haulage systems. The belt conveyor has also been used extensively as a main haulage unit in open-pit iron-ore mines of the Lake Superior district, particularly on the Mesabi Range. Few underground metal mines, however, either in the ferrous or non-ferrous branches of the mining industry, use the conveyors exclusively or even extensively for underground haulage. At present, only five iron-ore mines in the entire Lake Superior district have belt- or shaker-conveyor installations of any significant size. Of these mines, three are in the Crystal Falls-Iron River district of Michigan on the Menominee Range, one is on the Marquette Range near Ishpeming, Mich., and one is on the Mesabi Range near Keewatin, Minn.Results of the studies of tackless haulage in the Lake Superior district will not permit the establishment of any formula to prove or disprove the advantages of belt or shaker systems at all underground mines. The studies do show that trackless haulage can be used to advantage where the proper conditions exist. Advantages are particularly apparent when development can be planned sufficiently in advance of exploitation to permit installation of belts or shakers as part of the development program and where the systems are extended to include haulage in stopes as well as main entries.During the winter of 1947-48, the Bureau undertook a study of all of the underground ore conveying systems known to be in operation in the Lake Superior district for the purpose of making available to the entire mining industry the technologic data developed in the area. Because conditions that led to the installation of the belt and shaker conveying systems were often a function of the character of the deposit or the method of mining, a brief description of those conditions is included in this report.After a preliminary investigation into the extent to which trackless conveyors were employed in the district, it was found that a detailed study at five bites would result in fair appraisal of that method of haulage in the underground iron-ore mines.Each of the five significant installations is described separately in this report. In one instance, however, company policy does not permit identification of the mine wherein the conveying is done. In that instance the operation is designated as mine ""A"".Unless otherwise specified, all tonnage figures quoted herein are gross.The cooperation of officials of all of the companies operating underground mines in the Lake Superior district permitted successful completion of preliminary studies of mining practices and conveying systems.Special acknowledgment is made to R. D. Satterley, general superintendent, and to operating staffs of the Sherwood and Morris mines of the Inland Steel Co. The assistance given by W. D. Whitman, assistant superintendent, and Douglas Tippett, mine captain at the Morris mine, and P. D. Pearson, superintendent, R. O. Marsten, engineer, and W. Johnson, mine captain, at the Sherwood mine, is acknowledged."

Oct 1, 1949

By Jueun Lee, Jong-Hwa Yoon, K. Rider, Bernard J. Martin

Whole body vibration is known to affect movement accuracy [1], however little is known about changes in the organization of movement and movement strategies used to limit the influences of perturbations. The specific aim of this work is to analyze the motion and coordination of upper body segments of seated operators performing reaching tasks under whole-body sinusoidal vibration exposure and simulated vehicle ride motion. The long-term objective is to model reach coordination and predict the dynamic behavior of the upper body motion under vehicle vibration exposure. Method The reach task consisted of pointing with the right hand index finger to targets located on touch screens placed in front of the subject, 45° overhead and 90° to the right in the mockup cabin of an HMMWV placed on a 6 DOF ride motion simulator. The task was performed under stable (no vibration) and vibration (sinusoidal vibration or simulated ride motion) conditions. A motion capture system was used to record kinematic data of reflective markers to recreate body link trajectories. Joint angles (torso, shoulder and elbow; Figure 1) were then computed using quaternions. Coordination between body links was defined as a) the joints angle-versus-angle relationships between the upper arm and lower arm, and b) the joint motion onset relationships between torso, upper arm and lower arm in the time domain. Results Angle–versus-angle relationships. The relationship between upper arm vs. lower arm angle and torso vs. upper arm angle for a far forward reaching movement in the stable (solid lines) and vibration conditions (dotted lines) are illustrated in Figure 2. Fig 2A compares the control condition with a 4 Hz lateral vibration while Fig 2B compares the control condition with a 6 Hz vertical vibration. It appears that under vibration exposure the reduced upper arm extension is compensated by an increase in torso flexion. This effect is seen in the last phase of the movements (encircled areas). In addition, the lower arm extension is delayed under 6 Hz vertical vibration (Fig 2B left panel). Time of joint motion onset. The timing relationship between torso, upper arm and lower arm is largely a function of the target to be reached. Examples of delays between body links are illustrated in Figure 3. The control condition is compared to a 6 Hz vertical vibration for three

Jan 6, 2006

By D. J. Parker

On Thursday, March 18, 1937, the country was shocked by news of a terrific explosion at the New London, Tex., school, which caused the death of 280 pupils rind 14 teachers. The explosion occurred at about 3:05 p.m. in the largest of the 11 school buildings on the campus. Figure 1 shows this building, market; "Main high school building?, with respect to other buildings, pipe lines, oil wells, and gas lines on the property.

Jan 1, 1937

By W. W. Agey

As a part of the program of investigation of domestic sources of manganese in the western United States, engineers of the Bureau of Mines examined. and obtained samples of ore from two properties in the vicinity of Barstow, San Bernardino County, Calif. In addition to these, samples from two other properties in the same vicinity were submitted by the owners. As the ores were too low-grade to be acceptable for the direct production of ferromanganese, beneficiation studies were made to determine the amenability of the ores to concentration by ore dressing. The Big Reef manganese claims axe about 140 miles east of Barstow, Calif. The claims were leased by W., E. Thurber of San Gabriel, Calif., from the owner, C. S. VanDoren of Daggett., Calif. Manganese oxides occur as a replacement deposit in heavily brecciated andesite along a fault plane. Four samples were taken by an examining engineer of the Bureau of Mines from the ore zone, which, when composited, were representative of all the exposed ore. Preliminary tests were made on lot B, and final tests wore made on the composite sample. The Trans-Oceanic property is about 20 miles southeast of Barstow, near Newberry, in the. Pisgah mining district, Calif. The sample, submitted by the owners, was taken from a 1,000-ton reject clump from a hand-sorting operation. The ore occurs as a replacement of rhyolite.

Jan 1, 1952

By D. J. Parker

On Thursday, March 18, 1937, the country was shocked by news of a terrific explosion at the New London, Tex., school, which caused the death of 280 pupils avid 14 teachers. The explosion occurred at about 3:05 p.m. in the largest of the 11 school buildings on the campus. Fire 1 shows this building, marked "Main high school building", with respect to other buildings, pipe lines, oil wells, and gas lines or the property.

Jan 1, 1937

By L. C. IlsLey

"During the last eight years there has been a noticeable increase in the use of permissible equipment in gassy and dusty coal mines. This trend has undoubtedly been toward greater safety in mining, but in spite of this all is not well ""along the front.""In many mines those in charge, either through ignorance or supposed economy, have neglected to install sufficient copper and maintain good bonding on the rails used for return circuits to have a safe working voltage for the permissible equipment which is intended to afford them safety.Low voltage, when properly analyzed, is not economy but frequently is an expensive oversight. Burned-out armatures, controllers, rheostats, and switches are costly in themselves to repair or replace, but the greatest cost in many instances is the loss of production resulting from idle and broken-down equipment.From a safety standpoint, excessive low voltage where permissible equipment is necessary is almost criminal negligence. A burn-out of any kind is liable to cause an arc that may burn its way through a casing wall and bring about a hazardous condition if gas or dust in explosive proportions should be present. Again, all wiring, both interior and exterior to the apparatus, is subject to the extra heating consequent upon low voltage. It should be remembered that if the voltage drops the current must increase a corresponding amount in order that the same work may be accomplished; and as the heating effect is as the square of the current, an enormous overheating of the electrical parts and wiring often takes place. This heating effect is especially detrimental to trailing cables used on portable equipment, because under the most favorable conditions the size of cable selected is only barely sufficient to do its work properly at a safe working temperature; therefore, when the extra current load is added because of poor voltage, overheating is sure to result, with consequent deterioration of the insulation, This effect greatly increases the liability of cable failures in service, and in turn adds to the hazards incident to the use of portable equipment of the permissible type involving the use of trailing cables.Some manufacturers have tried -to protect their equipment from low voltage, especially below a certain point, by -installing low-voltage relays which will trip when the voltage falls to a predetermined value. It is understood that some operators have hesitated or refused to install such low-voltage protection because they were aware that the voltage conditions were so poor that the equipment could not operate under the safe limits set. It is difficult to understand how any progressive company that is willing to go to the ex-pense of installing permissible equipment could be so shortsighted in this phase of common sense, safety, and economy."

Dec 1, 1929

By Martin D. Conyac

Results of the minerals survey indicate low potential for the discovery of placer gold along Deck Creek aid for copper, silver, and gold in PreTertiary rocks within the boundaries of the Lake Fork RARE II area. Potential for oil, natural gas, coal, and geothermal resources is negligible. No evidence of economic mineral resources was found during the examination of the study area, and no assays of rock or placer samples taken from the urea showed economic mineral values. There are no producing or developing mines within the boundaries o of the lake Fork study area. SETTING Mining Districts The Lake Fork RARE II area is on the eastern fringe of the Cornucopia Mining District, which is centered about 6 mi west. It is also on the western edge of the Homestead district, centered about mi east.

Jan 1, 1983

By R. J. Gunderman

Redesigns of the operator compartments on a continuous miner and on a face haulage vehicle are described. The objective was to optimize the compartments within limitations of existing equipment and functional configurations. Both safety and production should be improved through more comfort for the operator and more natural placement of controls. Design guidelines supplied by the Bureau from a previous contract were used along with human factors analyses to determine requirements. Mock-ups were fabricated from layouts and used to refine design details. The new compartments were implemented and the machines evaluated underground. Comments and reactions to both machines were favorable.

Jan 1, 1978

By P. -E. Boileau, P. Marcotte, Y. Aldien, S. Rakheja

A number of biodynamic models of the hand-arm system have evolved on the basis of measured driving-point mechanical impedance (DPMI) responses to facilitate analyses of the coupled hand-tool system [1]. The parameter identifications in such models are based upon minimization of an error function of the model and the target impedance data, which may not yield a unique solution. Consequently, a number of model structures and parameter sets could be realized that would equally satisfy the target curve. Moreover, the vast majority of the reported models exhibit acute deficiencies due to excessive static deflections of model masses, presence of a low frequency mode and very light masses in the order of 1.2- 4.8 grams. The models also do not characterize the dependency of the biodynamic responses on many factors, namely the hand forces, hand-arm posture and vibration intensity. This study aims at development of a hand-arm biodynamic model with considerations of the hand forces, and both the DPMI and power absorption measures, to enhance the uniqueness of the model. Methods Two different model structures are chosen for identifying the model parameters on the basis of measured DPMI and absorbed power characteristics of the hand-arm system under zh-axis vibration over a range of hand-grip and push forces. Owing to the strong influence of the hand-handle coupling forces, the models were initially derived for fixed hand forces, namely 30 N grip and 50 N push forces, as suggested in the ISO 10068 standard [2]. The equations of motion for the model are formulated and solved to compute both the DPMI and absorbed power responses. A constrained minimization function comprising weighted errors of both the DPMI and absorbed power is formulated and solved to identify the parameters. Alternate functions corresponding to different combinations of hand forces are then applied to identify hand-force dependent model parameters. Variations in the model parameters are investigated as functions of the grip, push and coupling forces through linear regression analysis. Regression-based models are formulated for deriving the hand-handle forces dependent model parameters. The validity of the model is also examined under selected combinations of hand forces. [ ]

Jan 6, 2006

By G. L. Oldright, Virgil Miller

"This paper is the eighth; of a series on smelting in the lead blast furnace, and the third' of a group on the modifications brought about by the introduction of rich charges.ACKN0WLEDGMENTSThe data that appear in these articles were obtained through the courtesy of the operators of the Bunker Hill smelter at Kellogg, Idaho. The authors take this opportunity to express their appreciation to Stanley A. Easton, the vice-president and general manager, Frank M. Smith, smelter director, and to A. F. Beasley, the smelter superintendent, and his staff.INTR0DUCTI0NIt has been noted that the gases issuing from the top6 of the charges in the International Smelting Co.'s furnaces at Tooele, Utah, were very similar in composition to the gases from the top of the iron blast furnace, as they contained about 26 per cent of CO and 12 per cent of C02, the rest of the constituents being mainly nitrogen with a very little hydrogen and oxygen. It has been seen that where the column of coke was sufficiently high, the production of C0 gas to carry out the reduction of lead ores was accomplished in about the same manner as in a gas producer. In some cases, there was a little oxygen in the ""top gas"" -- usually not over a few tenths of a per cent, but at times amounting to several per cent. The presence of this gas was attributed to irregularities in operation that permitted air to come up through the tuybres to the surface without meeting any coke that was incandescent. Only a hundredth of a per cent or so of sulphurous oxides was present in the gases issuing from the top of the furnace."

Apr 1, 1931

By E. C. Baker

The capital investment and operating costs of two methane-control systems used during longwall mining operations are compared in this Bureau of Mines report. Costs are given for a surface gob hole drainage system and an underground cross-measure borehole drainage system to control methane gas in gobs in four coal mining areas--central Pennsylvania, northern West Virginia, southern Virginia, and northern Alabama. Present-worth analysis is used to determine the more cost-effective alternative in each location. The alternatives have equal lives and provide the same service based on a minimum rate of return of 15 pet. In central Pennsylvania and northern West Virginia, the gob hole system is more cost effective than the cross-measure system, by 10 and 18 pet, respectively. In southern Virginia and northern Alabama, the cross-measure system is more cost effective, by 29 and 38 pet., respecitively. Costs for other locations must be developed on a case-by-case basis.

Jan 1, 1988

By Charles A. Sorrell

This Bureau of Mines publication reviews the structural characteristics of crystalline phases and phase equilibria data for the system NaC1-KC1-AlC13-NaF-KF-AlF3, which encompasses a large number of molten salt fluxes currently used in aluminum recycling. Its purpose is to provide guidelines for research into the relationships between molten salt compositions and their physical properties, notably vapor pressures, densities, surface tensions, and viscosities, knowledge of which is essential to maximizing fluxing efficiencies and metal recovery and minimizing hazardous emissions and disposal problems. In addition, this report describes experimental determinations of sub-solidus compatibility relationships in the system, which is of the quaternary reciprocal type, containing 12 different stable 4-phase assemblages in the solid state. The compatibility diagram serves to define the important compositional planes across which important changes in properties are likely to occur.

Jan 1, 1986

By R. A. Beall, S. L. Ausmus

The development of a completely water - free expendable graphite mold material , useful for reactive metal castings , has been detailed . Mixing and curing variables have been evaluated both by physical testing of the material itself and by castings of titanium , zirconium , and hafnium . The blend of powdered graphite , cornstarch , dextrin , cereal binder , linseed oil , and Carbowax -4000 is a successful mix when mulled in a carbon dioxide atmosphere , and properly cured and fired . The primary advantage of this material is its adaptability to standard foundry techniques ; i . e . , core blowing and hand ramming . Temperatures in the curing and firing cycles do not exceed 960 ° C , and no vacuum firing is required .

Jan 1, 1964

By D. J. Bauer

The Bureau of Mines has conducted extensive studies on the recovery of alumina from kaolinitic clay by a HCI leaching-HCI sparging process. The current study reports a modification of the process, which involves a double-leaching system. The first leach of the calcined clay is made at as high a HCI acid strength as possible so that the dissolution of aluminum chloride hexahydrate (AlCI3*6H20) is suppressed, Most of the impurities, but very little aluminum, are soluble in the strong acid. After liquid-solid separation and washing, the solids are leached with recycled weak HCI, which dissolves the AICI3'6H2O. The pregnant liquor is separated from the gangue, and AICI3'6H2O is crystallized from solu-tion by injecting HCI gas. A proposed flowsheet is presented, and the effect of bleedstream size on AlC13'6H20 purity is discussed.

Jan 1, 1984

By A. Gene Collins

Rapid, sensitive, and precise methods of determing major, minor and trace constituents of oilfield brines are needed. Several methods have been developed or adapted by the Federal Bureau of Mines at the Petroleum Research Center, Bartlesville, Okla. The following methods are described in this report: Spectrophotometric and volumetric for iodides and bromides; potentiometric for pH, alkalinity, acidity, borate boron, total boron, and organic boron; gravimetric for potassium; disodium ethylenediaminetetraacetate (EDTA) volumetric for total hardness, calcium, and magnesium; spectrophotometric for fluorides; and color comparison .for arsenic. Adequate sensitivity, precision, and accuracy were obtained for each method. The Bureau of Mines pioneered in research on the analysis of oilfield waters (2, 46, 47).6 However, several of these early procedures were quite time consuming. Also, they did not include methods for determining trace and minor constituents of brines.

Jan 1, 1961

By Scott Turner

The present rapid growth of coal stripping in the United States is a curious reversal of the tendency of mining to proceed from outcrop to depth. A combination of technical and economic factors bas stimulated the use of stripping methods until today many million tons of coal We being recovered by open cuts from sites that an earlier generation of engineers would have passed by as not commercially mineable or, if workable at all, only by underground methods. The total quantity of bituminous coal and lignite mined in the United States by stripping in 1928, the latest year for which detailed figures are available, was 19,789,000 short tons. Of this, 71,000 tons came from small workings not equipped with power shovels and 587,000 tons from properties in which stripping and underground work were carried on at the same mine; but as neither of these types is representative of modern stripping practice, they will be omitted in the discussion that follows. The total from strip pits proper in 1928 was 19,131,000 tons, produced by 176 pits employing 385 steam or electric shovels.3 Figures by States are given in Table 1. Detailed statistics will be found in Economics of Strip Coal Mining; a study by O. E. Kiessling, to be published by the United States Bureau of Mines.

Jan 1, 1930

By Michel C. Frippel

This section of the Minerals Yearbook reviews the minerals industries of 45 countries: the 12 nations of the European Community (EC) (Belgium, Denmark/ Greenland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Portugal, Spain, and the United Kingdom); 6 of the 7 nations of the European Free Trade Association (EFTA) (Austria, Finland, Iceland, Norway, Switzerland, and Sweden); Malta; the 11 Eastern European economies in transition (Albania, Bosnia and Hercegovina, Bulgaria, Croatia, Czechoslovakia, Hungary, Macedonia, Poland, Romania, Serbia and Montenegro, and Slovenia); and the countries of Central Eurasia (Armenia, Azerbaijan, Belarus, Estonia, Georgia, Kazakhstan, Kyrgystan, Latvia, Lithuania, Moldova, Russia, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan).

Jan 1, 1994

By John R. Benham

The Windigo Theilson RARE II area has a low mineral potential. There are no mines or claims in the area. The only observed results of mining activities were five prospect pits near Tolo Mountain. Samples from these pits contained no significant assays. The study area contains more than 190 million cu yds (145 million m3) of cinders in 17 cones. Development of these cinders is unlikely because their locations are remote, and other sources supply area needs. The Geological Survey has classified the area as prospectively valuable for geothermal resources. However, there has been no geothermal exploration activity.

Jan 1, 1982

By Gerrit V. R. Goodman

Future coal mining systems will be able to cut from crosscut to crosscut where advances could exceed 100 ft. However, limitations arise when ventilating such mining systems. In deep advance mining, there would be no workers at the face to advance ventilation tubing or curtain manually. Traditional methods also provide no means for maintaining face ventilation after the miner backs away from the face. U.S. Bureau of Mines research is studying means to provide effective ventilation at cut depths beyond the current limit of 4D ft. Several innovative ventilation schemes are currently being considered. One such method is the use of a jet fan to ventilate a deep cut. A jet fan is simply a freestanding fan using little or no ducting to direct the ventilation flow. Jet fan testing in a 90-ft entry revealed that higher exit velocities and greater penetration depth occurred when various configurations were used to confine and direct the air flow. Additional testing also indicated that 2,200 cfm of fresh air was delivered to the face? 90 ft distant when a check curtain was used to limit entrainment around the fan. Without this curtain, this quantity dropped to only 1,000 cfm. This testing indicated that a jet fan was capable of providing ventilation to a distant face area. It also highlighted potential problems, such as recirculation at the fan and reentrainment in the jet flow. Despite these potential problems, jet fans may be adequate for ventilating cuts exceeding 4D ft.

Jan 1, 2010