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By Edmund S. Leaver

[In previous reports5/ of ore-testing studies standard methods of conducting; test with precious-metal ores selected as representative of certain mining districts were discussed in considerable detail. In addition to standard tent procedures such as direct cyanidation, amalgamation, gravity concentration, and flotation, or a combination of these methods, it is sometimes necessary to apply other methods, such as preliminary roasting and washing of the calcine with plain or acidulated water before cyanidation. In all of this work standard tenting procedure has been supplements by he necessary assaying and analyses of original ore and test products.]

Jan 1, 1941

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 Roger M. Turpening

This study was performed to examine the feasibility of using seismic shear waves to detect the presence of abandoned coal mines. !he Antiquity Coal Mine near Antiquity, Ohio was used as a region of known voids. No attempt was made here to accurately locate the mine tunnels if detection was obtained. The results of this study were positive. Sharp changes in the amplitude of the received shear waves were clear indications of the presence of a fluid (gas or liquid) filled region between the source and receivers. When moving the source showed no change in the received signals it was concluded that the voids existed beneath the sensors. Prior to these tests drilling (SM-3) had determined that a void did exist in this area. This void was confirmed by this shear wave test and two additional voids were found.

Jan 1, 2012

By S. H. Lorain

Tin mining on Seward Peninsula, Alaska, has been intermittently active since the early 1900's. Most of the recorded production (over 2,200 short tons of metallic tin) has been obtained from placer deposits, but recent production also has resulted from development of lode deposits associated with intrusive rocks occurring in the western part of the peninsula. Generally, the lode deposits containing tin minerals (principally cassiterite) are found in dikes, in granite masses, and in silicate zones in limestone overlying the granite. Both the placer and lode deposits have been of considerable strategic interest to the Government because of the almost total absence of a domestic supply of tin. The most important tin-lode deposit discovered to date is in the Cassiterite dike at the Lost River mine, on Cassiterite Creek about 85 miles northwest of Nome. This highly altered, rhyolite porphyry dike averages 12 feet in thickness, strikes N. 75° to 85° E., and dips steeply to the south; it can be traced on the surface for about 8,000 feet. Throughout its explored length of about 2,200 feet the dike everywhere contains some tin and tungsten in veinlets and disseminations; economic concentration of the are minerals, however, is confined to definite shoots. The ore minerals include cassiterite, stannite, hulsite, paigeite, wolframite, scheelite, and base-metal sulfides; gangue minerals include fluorite, boron silicates, and lithium-bearing minerals. Some ore minerals also occur in the numerous other dikes and in the granite and intruded limestone in and adjacent to the mine.

Jan 1, 1958

By John D. Foulkes

An investigation is made into whether commercially available equipment can be used to engineer effective emergency warning systems for underground coal mines. Discussions with members of the Bureau and the Mining Enforcement and Safety Administration established that the preferred system should operate over the existing Pager Phone twisted pair, and broadcast an audio alarm. Applicable equipments such as voice band tone signaling equipment, alarm sounding equipment, mine telephones and complete alarm systems from over thirty manufacturers are listed. Factors affecting the range over which an alarm could be detected in representative mine situations were studied. These included (a) the subjective masking effects of typical background noise found in mines, such as that due to continuous miners (b) the attenuation of sound in mines (using both a theoretical and experimental results) and (c) the attention-getting qualities of different sound for miners. Audio alarm systems meeting the requirements can be installed and representative systems are described.

Jan 1, 1977

By John C. Machisak

THIS CHAPTER of the Minerals Yearbook (Volume III) contains overall injury experience for coal mines, both anthracite and bituminous, coke plants, petroleum and natural gas, peat, and asphalt and related bitumens (native); metal mines, their metallurgical plants, including ore-dressing plants and primary nonferrous reduction plants and refineries; nonmetal mines; nonmetal mills; sand and gravel operations; slag (iron blast-furnace) plaints; and stone quarries and their related pants. Volume I of the yearbook contains a chapter showing injury experience and employment data treated separately by metal mines, nonmetal mines, quarries and their related plants, metallurgical plants (ore-dressing plants and primary nonferrous reduction plants and refineries are shown separately), nonmetal mills, sand and gravel plants, and iron blast-furnace slag plants. Volume II contains injury and employment experience in the fuel industries (coal, coke, petroleum and natural gas, asphalt and related bitumens (native), and peat. Injury and employment data are submitted voluntarily for the mineral operations through an industry canvass made by the Bureau of Mines, except for the coal industry, whose reports are mandatory. Information published in this chapter is the result of this canvass. Figures presented in this chapter for 1961 are preliminary except for anthracite, peat, coke, petroleum and natural gas, asphalt and related bitumens, and slag. These preliminary data, with the exception of bituminous coal, are a summation of reports received by May 31, 1962, from the operators showing their injury and employment experience. Estimations of injury and employment experience are not included in these preliminary data.

Jan 1, 1962

By James A. Wasson

This report summarizes the results and conclusions reached by various investigators who have attempted to determine the extent to which hydraulic fracturing will affect the secondary recovery of crude oil by waterflooding. It also discusses the most advantageous use of this well-stimulation method in waterflood projects. A thorough search of the literature was made, and pertinent information was abstracted from appropriate reports. A carefully designed and controlled program of formation fracturing is an effective aid in waterflooding because it increases water-injection and oil-production rates. Generally, fracturing has resulted in little or no reduction in ultimate oil recovery, but under certain circumstances recovery has been substantially increased.

Jan 1, 1963

By Glen C. Reed

"The Avon mica district of Latah County, Idaho, is situated on a heavily forested spur of the Thatuna Range at an average altitude of 4,000 feet. The nearest rail connection is at Avon, a small farming settlement 7 miles to the south. The main supply point is Moscow, Idaho, which is 35 miles by graveled and graded county roads from Avon.Discovery of mica-bearing pegmatites in 1885 was followed in 1888 by exploitation of several outcrop deposits. Although factual data are unavailable, past production appears to have been well in excess of $100,000. Recent production (September 191 to April 1945) amounted to 65,824.78 pounds of trimmed sheet mica and 33,294.17 pounds of punch mica having a total gross value of $434,298.The several properties of the district are variously owned by estates, individuals, and the State. When active, all wore under lease or sublease to individual operators.The deposits are in an area of pre-Cambrian schists adjacent to a small granitic outlier of the Idaho batholith. The pegmatites are nearly concordant in dip and strike to the foliation of the enclosing schists. The more persistent bodies are usually tabular, lenticular, or pegmatite. Individual dikes range in length from 10 feet or less to 300 feet.The recoverable crude mica content of the pegmatites ranges downward from a maximum of 115 pounds per ton of pegmatite mined. Material discarded in rifting and trimming operations further reduces recovery to a maximum of 5 pounds per ton -of pegmatite mined. The average recoverable sheet content of the 'recently operated .deposit is estimated at 2 pounds per ton of pegmatite -mined. Available data indicate that about 21 percent of the district's recent production of trimmed sheet mica has been ""Group A"" material suitable for exacting condenser requirements. A few of the dikes contain local concentrations of beryl.Reserves of the three known major deposits of the district are estimated at about 600 to 1,000 tons of combined ""indicated"" and ""inferred"" crude block mica. One of these deposits is inferred to contain between 150 and 450 tons of beryl.It is believed that those mica reserves are minable only under a cost-market price ratio similar to that established during 1943 and 1944. A small part of the reserves can be ""high-graded"" under the present price structure. Profitable recovery of the beryl would require a market price four to five times that paid in 1944.Preliminary examination of the Avon mica district was made by the Bureau of Mines in the summer and fall of 1942. A study of the Muscovite mine and a brief reconnaissance of the surrounding district led the Bureau to recommend that the district be explored by angle-dozer trenching."

Jul 1, 1946

By Terry R. Neumann

A mineral survey of the 23,760-acre Abert Rim Wilderness Study Area (OR-1-101) was conducted by the U.S. Bureau of Mines in 1986 at the request of the Bureau of land Management in order to evaluate its identified mineral resources. The study area is located in south-central Oregon, 26 mi north-northeast of Lakeview, OR. Federal and Lake County mining records indicate no mining claims, geothermal leases, or oil and gas leases within the study area as of January 1, 1987. No economic concentrations of minerals were found in the study area. The Wilderness Study Area is dominated by Abert Rim, a north-trending Basin and Range fault scarp that parallels the study area's western boundary. Exposed on the scarp is an approximately 2,000-ft-thick volcanic sequence consisting of Oligocene-Miocene basalts, tuffs, and tuffaceous sedimentary rocks.

Jan 1, 1987

By C. L. Brown

"INTRODUCTION The heavy loss of life from mine fires in some coal mines recently has focused attention on the importance of maintaining reliable communication systems between the active working sections of mines and the surface. A study of conditions following disasters in mines indicates that in several instances lives could have been saved if telephone communication had been available. Communication systems were not installed in some of these mines where disasters occurred, and in other mines they were installed in such a manner as to be rendered useless following a mine explosion or fire. Lives have been lost because of the inability of the rescue crews or persons di-recting the rescue to communicate with trapped men. Cases are known where many lives might have been saved had it been possible to give instructions for escaping or for location of barricades.More than 500 major disasters in which 5 or more lives have been lost have occurred in mines in the United States. The total number of lives lost in these disasters has exceeded 13,000. Some of the victims died instantly; but for many it was hours and in some instances days before death occurred. Evidence found in recovery operations following some of the disasters indi¬cates that many died needlessly because of the lack of suitable means of communication between the underground working areas and the surface.A localized gas and dust explosion in a coal mine in 1930 resulted in the death of 82 men; 2 were killed outright by the force of the explosion, 6 by a combination of burns and afterdamp, and 74 by afterdamp. About 140 men escaped or were rescued following the explosion, Of these, 119 escaped with little or no assistance, 2 were rescued promptly following the explosion, and 19 were rescued from behind a barricade. Seven bodies were re-covered from behind an ineffective barricade in another place; subsequent investigation proved that these men might have been guided to a safe location had an effective communication system been available."

Oct 1, 1946

By Samuel M. Bryant

The purpose of this study was to develop procedures to measure Bingham flow properties for mine tailings and to use these to predict the possible consequences of a hypothetical tailings flow failure at the Tenmile Tailings Pond at Climax, Colorado. The consequences of such a failure were found to be minimal, and the failure itself highly; unlikely. Values of Ty (Bingham yield shear strength) and np (plastic viscosity) were measured for 10 materials using results obtained from vaned coaxial viscometer tests and triaxial tests.

Jan 1, 1983

This report is a proceedings of a briefing recently sponsored by the Bureau of Mines at which Bureau personnel presented findings from their research efforts to improve steelmaking techology currently used in the United States. The papers contained in this report address many areas of concern to the iron and steelmaking industry. Among these are improving arc stability in electric arc furnaces, preheating ferrous scrap to reduce energy consumption, fluorspar substitutes in steel-making, basic steelmaking refractories, corrosion of iron-based materials, improvements in stainless steel acid pickling processes, recycling of stainless steel dusts and other wastes, and use of wastes as a source of zinc for electro/galvanizing.

Jan 1, 1988

By Oliver C. Fursman

The Bureau of Mines undertook this investigation in order to determine the feasibility of producing commercially acceptable alumina and iron by application of the Pedersen process to high-silica, high-titania, ferruginous bauxites of the Pacific Northwest. Calcium aluminate slags were produced by smelting bauxite with coke and lime in an electric-arc furnace. Over 90 percent of the total alumina can be extracted by sodium carbonate solution from slags of properly controlled ternary-phase composition (CaO-Al203-SiO2) that are cooled slowly enough to permit adequate crystallization of the 2CaO-SiO2 and the calcium aluminate compounds. Most of the iron charged was recovered in the regulus; the slag contained about 2 percent iron (as iron oxide), regardless of smelting time.

Jan 1, 1968

By Charles F. Jackson

Waste filling has been employed for many years for supporting the walls of stopes and preventing failure and subsidence of the surrounding and overlying rock formations, and its effectiveness for this purpose has long been recognized. It is used for permanent support in ground where timbering (including square-setting) is inadequate for more than temporarily supporting the walls of the excavations. It should be rioted, however, that effective as a good, solid fill may be in resisting heavy side pressure and direct weight, its usefulness for supporting large areas of back and preventing breaking and movement of the overlying rocks is limited. Even the strongest and most uniform rocks will break if the unsupported span becomes too great; and since filling cannot be packed tightly against a horizontal back there is always a possibility of the back breaking and consequent subsidence if the maximum self-supporting span is exceeded. Planes of separation, such as bedding and fault planes, slips, and joints, are common in all rock masses; these may occur above the stoping area where their presence cannot be ascertained by observation. If too much reliance is placed upon filling for the support of a large horizontal area of back (as contrasted to support of vertical or steeply inclined walls) large masses of rock may break along a. plane of weakness, compress the fill, and leave an open space into which caving of the overlying rocks may continue until the space is filled. In this paper the term "waste filling" includes any filling material other than ore - waste mine rock, rock from surface quarries or opencuts, sand and gravel, mill sands, or slags from smelting operations.

Jan 1, 1935

By K. E. Stanfield

This report presents the results of analytical studies made on two series of oil-shale samples from the Mahogany ledge of the Green River mine the character of the various grades of oil shale that are being mined and processed into shale oil and refined products at the Bureau of Mines Oil-Shale Demonstration Plant at Rifle, Colo. The analytical work was part of a synthetic liquid fuels program being conducted at the Petroleum and Oil-Shale Experiment Station, Laramie, Wyo. The 16 oil shales ranG6d in color from a gray brown ( or a sample that assayed 10.5 gallons of oil per ton to a very dark brown for a sample that assayed 75.0 gallons of oil per ton. In general, the samples were similar as to the types of organic and inorganic matter that they contained but varied widely in the amounts or these constituents. The principal constituents were calcite, dolomite, illite, and yellow organic material, while the minor constituents were quartz, feldspar and plagioclase feldspar, pyrite, marcasite, analcite, opal, black organic material, and small woody fragments. Some micro-fossils, spores and pollen grains were found also.

Jan 1, 1951

By George T. Faust

The petrographer engaged in examining the products resulting from the beneficiation of ores and rock minerals is constantly required to develop new means and methods of assaying microscopically the results of such operations. From time to time investigators have published descriptions of apparatus that have aided in solving problems in processes f physical separation. Thus, in 191.9, Coghill and Bonardi 31 published a paper covering the application of the binocular microscope and camera lucida to the microscopic analysis of pulverized ores. Similar work has been published by Schneiderhohn 4/, Schwartz 5/, and Head and his associates6/, 7/, 8/. The present paper goes further and considers application of the polarizing comparison-microscope to problems directly concerned with mineral dressing where it is desirable to compare analogous products, and in addition it suggests new uses in various related fields. This work was conducted under the cooperative agreements of the Southern Experiment Station of the Federal Bureau of Mines and. the University of Alabama.

Jan 1, 1940

By Lloyd H. Banning

With the ever-increasing demand for energy in all forms, electrical energy generated from geothermal resources could become an important energy source in the next few decades. Geothermal fluids, which contain appreciable quantities of dissolved salts and gases, are generally corrosive to materials of construction. Since data on corrosion of materials in geothermal brines is limited, the literature was surveyed through February 1972 to obtain a compilation of information on corrosion resistance of aluminum and its alloys, copper and copper-base alloys, carbon steel and cast iron, stainless steels, chromium-iron alloys, nickel-and cobalt-base alloys, and titanium in heated brines including sea water.

Jan 1, 1973

Protect mine rescuers from heat-induced stress that drastically cuts their endurance and saps their strength. Approach To prevent exhaustion caused by thermal stress, a rescuer can wear a liquid-cooled hood and vest which absorbs heat, thereby reducing the heat-induced strain on the rescuer's heart and circulatory system. How It Works Liquid coolant is continuously circulated through a self-contained system in which the coolant is chilled by a heat sink on the wearer's belt. The coolant, which is a mixture of alcohol and water, is pumped from the heat sink to bladders inside the hood and vest where it absorbs body heat. After absorbing heat In the hood and vest areas, the coolant returns to the heat sink where it is rechilled by passing through a tube coiled around a steel can containing a block of ice. To adjust the temperature of coolant leaving the heat sink unit, a valve can be operated by the wearer, causing part of the flow to bypass the coil. A small pump and a rechargeable battery are also part of the assembly.

Jan 1, 1979

By Ren G. Dong, Kristine M. Krajnak, Dan Welcome

Continual occupational exposure to vibrating hand tools can damage the neural, vascular and other soft tissues of the fingers. Rat tail models have been developed to investigate the biological responses of the tissues to vibration.1-2 However, the biodynamic response of the tail relative to that of the human fingers has not been characterized. The objective of this pilot study was to compare the transmissibilities of rat tails measured via a scanning laser vibrometer to those of human fingers gripping a handle. Methods In Part I of this experiment, four male Sprague Dawley rats (6 weeks old) were exposed to discrete 5g-rms sinusoids of 32, 63, 125, 160, 250, and 500 Hz. The rats were restrained in Broome-style restrainers with their tails constrained without compression to an exposure platform via elastic straps as shown in Figure 1. The platform was attached to a vertically vibrating shaker. The vibration was measured for the array of points shown in Figure 1 using a scanning laser vibrometer (Polytec) and the transmissibility calculated for each point on the tail relative to the reference points on the platform. In Part II, three male human subjects were exposed at the frequencies specified in Part I - with the addition of 1000 Hz - at a magnitude at the ANSI <0.5-hr limit up to 63 Hz, after which the acceleration was held constant at 5g-rms. The subjects gripped an instrumented handle at 20 N as shown in Figure 2. The transmissibility was calculated relative to the reference points on the handle. [ ]

Jan 6, 2006

By Donna L. Anderson

This U.S. Bureau of Mines report describes a system to determine the position and heading of a continuous mining machine during the maneuvers required at the face area of a mine. The system consists of commercially available angular position sensors and a computer interface developed and tested at the Bureau. The sensors employed are laser-based scanning devices that report the angular location of retroreflective targets within their 90° field-of-view. The targets are mounted on the continuous mining machine; the laser scanners are mounted on an external reference structure. The computer interface consists of a single-board computer-controller programmed to gather and process the angular position information, and to calculate the machine&apos;s position and heading relative to the reference structure. A sensor fusion algorithm will be incorporated into the computer interface programming to increase the accuracy and reliability of the system.

Jan 1, 1989