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By Stanton L. Tainter

"As an adjunct to its minerals-investigation program, the Bureau of Mines has developed a number of operating devices and techniques worthy of note. This paper, prepared under the supervision of J. H. Hedges, chief, Tucson Branch Mining Division, and under the general supervision of Lowell B. Moon, chief, Mining Division, reports upon certain methods devised to overcome difficulties encountered in cementing of diamond-drill holes at a Bureau of Mines project at Christmas, Gila County, Ariz.Pressure grouting was employed to recondition a caved hole it was desired to reopen and deepen. The hole, which had boon stopped 7 months previously at a depth of 488 feet, was caved below 449 feet in a contact zone of claylike, altered diorite and crumbly metamorphosed limestone. As other means of obtaining moderate pressure were not available, carbon dioxide gas, drawn from tank of liquid carbon dioxide through a pressure reducing and regulating valve, was used. The hole was reopened successfully with 12 grouting jobs.Another hole, where cawing from several water-bearing fractures between 202 and 232 feet gave trouble, was successfully cemented by the use of a grouting plug. An attempt to cement through the rods had failed, owing probably to agitation caused by water currents. Pressure grouting through the caning set above the cave could not be need, because water was forced up outside the casing when pressure was applied. The problem was solved by using a wooden plug 1-13/16 inches in diameter, which, when soaked in water, expanded to a tight fit in an AX hole. A hole was drilled through the plug, and a rubber flap valve was nailed to the lower end. In the upper end of the plug the hole was enlarged to fit loosely over an EX rod coupling finished smooth. The plug was lowered on the end of the drill rods to a point about 10 feet above the cave, where it was allowed to expand tightly to the hole. Cement grout was then pumped through the rods, and the rods were removed from the hole. After allowing time for the cement to set, the wooden plug was chopped out and drilling van resumed.Over 300 tests were made to determine the type of cement most suitable for use on the Christmas job, and the effect of cement-water ratio, temperature, and various admixtures on workability, setting time, and strength. The results of these tests, described in detail in the body of this report, indicate the desirability of thoroughly testing available cements when it is necessary to drill holes under difficult conditions that may cause failure.When it became desirable to reopen and deepen a caved drill hole, it was considered easiest to recondition the hole by pressure grouting, As other mans for obtaining moderate pressure were not available, a method utilizing carbon dioxide gas was employed. The hole was reconditioned successfully with 12 grouting jobs."

Nov 1, 1949

By H. H. Schrenk

There are several well-recognized procedures for controlling exposure to hazardous atmospheres in industry. They include (a) substitution of less toxic material, (b) enclosure of processes, (c) wet methods, (d) local exhaust, (e) general ventilation, and (f) use of respiratory protective devices. In addition to their employment as a control measure in occupational exposures, respiratory protective devices also are essential in emergencies that may arise from failure or improper use of other control equipment. Respiratory protective devices usually are employed to supplement other methods of control, as temporary expedients, or when other methods are not readily applicable or practicable. It seems reasonable to assume, however, that where respirators are used consideration has been given to the factors involved and that the devices can provide satisfactory protection if used properly. Their use should not be arrived at simply by a process of elimination of other methods that are more difficult to apply.

Jan 1, 1943

By Robert C. Johnson

Single crystal whiskers of ZrO2 and TiO2 were grown by solution and crystallization of these oxides in molten baths. Mixtures of Na2B407 and LiC1 were the most suitable growth media for zirconia. Sodium borate alone and Na2CO3 plus SiO2 were best suited for titania. The solubilities of zirconia and titania in molten sodium borate were determined, Whether zirconia whiskers were dendritic or nondendritic depended on the temperature used. The best single crystal whiskers were grown below 1,100° C. Titania whiskers always grew as single crystals. The tensile strengths of zirconia and titania whiskers were about 15,000 psi and 50,000 psi, respectively. Modulus of rupture was about 49,000 psi for zirconia whiskers and 75,000 psi for titania whiskers. Chemical analyses showed the zirconia and titania whiskers to be pure. The zirconia and titania whiskers were shown by X-ray analysis to be, respectively, baddeleyite and rutile.

Jan 1, 1965

By Robert L. de Beauchamp

The Bureau of Mines reviewed aluminum chloride technology to determine the problems associated with its preparation from minerals, and to ascertain the best areas for research to solve these problems. Commercial AlC13 production processes are described and the ?state of the art? for the preparation of AlC13 from aluminous materials is evaluated. Areas for further research are indicated.

Jan 1, 1969

By T. T. Read, T. L. Joseph, F. H. Royster

In a preliminary study of the beneficiation of iron ores conducted by the Bureau of Mines, one of the authors (T. T. Read) found it necessary to ascertain, if possible, how much effect a decrease in the silica content of an iron ore has upon the cost of making pig iron from the ore. In the beneficiation of iron ores the most important impurity to be removed is usually silica, and the amount that can be expended on a beneficiation process to reduce the silica content of the ore is obviously determined by the amount of increase in the value of the ore after beneficiation. The price that can actually be obtained for a beneficiated ore is, of course, a matter of negotiation between the seller and the buyer, but since the relative value of different grades of iron ore must be chiefly based upon the cost of making pig iron from them, an approximation as to the effect which decrease in the silica content of ore has upon the cost of snaking pig iron is an important guide in estimating what probable average gain will result from subjecting an ore to a beneficiation process. A search of the literature failed to reveal any detailed statement on this important topic, but fortunately the data are at hand to permit making an approximate calculation of the probable effect. For the purpose of the calculation assume three iron ores with the following composition (natural):

Jan 1, 1924

By F. A. Rutledge

The Bureau of Mines Investigated the Copper Bullion claims at Rua Cove on the east coast of knight Island in Prince William Sound, Alaska, during November-December 1948 and March-April 1949. This project was part of the Bureau of Mines program for developing critical and strategic minerals in Alaska, Mineralization at the copper deposit on the Copper Bullion group of claims is mainly pyrrhotate and chalcopyrite, confined to a northeast-trending shear zone in the greenstone 2,000 feet northwest of Rua Cove. The property has been partly developed by two adits, by a number of crosscuts from the upper adit, and by several diamond-drill holes.

Jan 1, 1953

By Verne E. Hooker

The Bureau of Mines conducted a preliminary investigation to determine the state of stress in crystalline rock outcrops near Atlanta, Ga. The secondary principal stresses in a horizontal plane near the surface are compressive and are 500 to 3,000 psi. The maximum compressive stress is northeast-southwest in the Stone Mountain-Lithonia district but changes to northwest-southeast near Douglasville. The elastic constants were determined from data obtained by static and dynamic laboratory methods and in situ velocity measurements. Results show Young's modulus to be dependent upon both stress level and anisotropy in the rock. Average secant moduli obtained from triaxial tests were used to compute the applied stress from borehole deformation measurements.

Jan 1, 1966

By B. J. Scheiner

Electrooxidation of cinnabar mercury ores (HgS) was investigated as a means of providing an effective and economical hydrometallurgical technique for extraction of mercury from its ores, particularly those too low in grade to allow economical metal recovery by retorting or furnacing techniques. Oxidation was accomplished by electrolysis of ere slurried with brine. Cinnabar was dissolved by oxidation of the insoluble sulfide to soluble mercuric salts. The mercury ion in a brine solution forms a stable tetrachloro complex. Typical laboratory experiments required I to 7 hours of electrolysis at 35-percent pulp density in a brine solution that contained 4 to 20 weight-percent sodium chloride (NaCl). Power consumption ranged from 10 to 50 kwhr/ton of dry ore. Mercury extraction values between 90 and 99 percent were obtained with all of the ores investigated. Subsequent mercury recovery from leach solutions was readily accomplished by precipitation on zinc. Pilot mill experiments in a 100- to 200-lb/hr extraction plant are in progress to quantify power and reagent requirements, and extraction and recovery data obtained to date closely parallel those obtained in the laboratory.

Jan 1, 1970

By Constantine C. Popoff

"INTRODUCTION AND SUMMARYDuring 1946 several high-grade limestone deposits in western Washington were examined by the Bureau of Mines. This report presents the data obtained from investigation of the Sauk Mountain deposits in east-central Skagit County, Washington.The investigation consisted of transit and topcgraphic surveys and sampling. The areas selected for sampling were first cleaned by blasting; channel samples up to 40 pounds were cut where practical. Chip samples averaging 30 pounds were taken where channel samples could not be cut. A total of 21 samples in the Sauk Mountain area were taken and. analysed. The locations of the samples are shown in figures 2 and 4, and the analyses are listed in tables 1 and 2. This investigation is a part of a long-range program of general investigation of mineral resources for future industrial development of the Pacific Northwest. The Sauk Mountain deposits were investigated for the purpose of disclosing now sources of high-purity limestone, which could be mined and shipped at low cost to Seattle and other industrial cities in the Pacific Northwest."

Oct 1, 1948

By P. R. Bremmer

As part of a program to devise alternative technologies for producing alumina from domestic resources, the Bureau of Mines investigated the leaching of calcined kaolinitic clay to form basic aluminum chloride solutions. Bench-scale experiments were conducted for single-stage batch leaching with AICl3 solution and three-stage countercurrent leaching with substoichiometric HCI. Variable conditions of clay calcination and leaching were studied to determine their effects on aluminum extraction and pregnant liquor composition,

Jan 1, 1984

By R. R. Sayers

Carbon monoxide poisoning, as usually encountered, is an acute condition resulting from breathing atmospheres containing that gas. It is characterized clinically by headache, dizziness, weakness in the legs, increased respiration at first which later becomes irregular and depressed, collapse, unconciousness, and death; anatomically it is characterized by temporary changes in the red blood cells due to the combination of carbon monoxide with hemoglobin, and, in prolonged severe exposures, degenerative changes in various tissues of the body, especially those of the central nervous system. No race or nationality is immune or has a, special tolerance for carbon monoxide. From data at hand, it is known that both sexes are about equally susceptible. All ages are affected, but small percentages seem to have a more deleterious effect upon young animals and this is possibly true of children. Exercise, high temperature and humidity, and low oxygen content of en atmosphere increase the degree of poisoning for a certain concentration of carbon monoxide. Anything that lowers the physical fitness of a man, such as illness, overwork, or excesses of any kind, exaggerates the effects. More cases of poisoning from carbon monoxide occur in coal mines in the cold months of the year, because explosions take place more frequently during that period, also in homes where gas is used for beating purposes, and in garages from accumulation of automobile exhaust gases due to poor ventilation.

Jan 1, 1923

By Lee M. Manna

Approximately 10,000, 10-Ton, 4 wheel, 2 truck, coal mine cars are in general service in U. S. Mines. None are equipped with an automatic braking system. Very few are equipped with hand or parking brakes. The report lists major manufacturers of the car and develops estimate as the percentage represented. It complies physical specification of cars of major car manufacturers, and develops a composite clearance diagram. It then discusses a pneumatic system employing truck components for an automatic system that could be used as an add-on unit. The components are listed and priced and a schematic circuit is developed for the system. Recommendations as to future programming are made.

Jan 1, 1976

By Charles L. Ross

A successful placer mine is being operated by the E. T. Fisher Co. on Rock Creek in the South Pass mining district at Atlantic City, Wyo. About 2,800 cubic yards of gravel is dug daily by a gasoline-driven dragline shovel with a 1 1/4-yard bucket and washed in a movable plant with a gold-dredge trommel and standard-dredge sluice boxes; the total cost is about 12 cents per cubic yard. The gold-bearing gravel occupies a narrow valley between two low ranges, of hills. The ground is covered by brush and willows, which are cleared of in the fall by burning after the leaves have dried. The elevation at the mine is 7,600 feet above sea level.

Jan 1, 1935

By R. Blickensderfer

Several thin film absorber stacks with spectrally selective characteristics were developed by the Bureau of Mines. The stacks consisted of a silicon thick film or a zirconium compound thin film on a reflective thin film of silver. The zirconium absorber films, with the general formula ZrCxOyNz, were prepared by reactively sputtering zirconium or zirconium carbide in argon with small amounts of oxygen, nitrogen, or both, or by oxidizing zirconium films in air. A few similar types of films were prepared from titanium. The short-wave absorptance over the solar spectrum, a(s), and thermal emittance at 600 K, e(600 K), of the solar absorber stacks were calculated from room-temperature reflectance data. The values of a(s) ranged from 0.47 to 0.93, e(600 K) from 0.49 to 0.034, and the ratio a(s)/e(600 K) from 1.7 to 34. The specimen with the best combination of properties, a ZrNx-Ag stack, had a solar absorptance a(s) of 0.85 and a ratio, a(s)/e(600 K), of 24. The effect of film thickness and composition on spectral selectivity was determined. An emissometer for measuring normal total emittance up to 800 K and a method for determining a (s), e(T) (hemispherical), and a(s)/e(T) using simulated solar radiation are described. A calorimetric method for measuring a(s) and e(T) (hemispherical) at elevated temperature is also described. Measurements made on several specimens agreed favorably with calculated values.

Jan 1, 1976

By Lloyd A. Morley

This report abstracts project work performed under USBM Grant GO155003 during the period 4 November 1975 to 3 November 1976. The research was funded, as a continuance of previous support from USBM Grants GO133077 and G0155003, to gain further knowledge in mine electrical system safety. Five reports have been separately produced, all under the grant title, "Coal Mine Electrical System Evaluation," and are as follows: 1. Volume I - Continuous Monitoring, 2. Volume II - Transient Analysis, 3. Volume III - Shielded Cables, 4. Volume IV - Computer Modeling, and 5. Volume V - Battery and Battery-charging Safety. Abstracts of these comprise the balance of this document with one exception. The task ?d-c offsett currents," does not fall under the scope of the other report volumes and, further, the material to be presented does not justify a separate report. Hence, this subject concludes the Executive Summary.

Jan 1, 1977

By E. R. Palowitch

This report stems from a study by the Bureau of Mines of the possibility of reducing coal filter-cake moisture by applying radiant heat directly to the filter cake while under vacuum during the drying phase of the filter cycle. One disk of a 4-foot-diameter vacuum filter was equipped with gas-fired radiant-heat generators and the effect of radiant heating on the moisture content of a variety of filter cakes was studied. The results of this investigation show that this process can best be described as a filter aid capable of increasing the effectiveness of conventional filtration approximately 6 percentage points of moisture. The operating cost of removing water by this method is somewhat lower than the average operating cost of thermal drying and is considerably cheaper when the total cost is considered. Removal of water from coal that has been wet-cleaned is an important part of the overall coal preparation process. Water is a contaminant, and it is foolish to wash coal to reduce its ash content and add inert water in the process. In some instances the removal of water is actually more important than the removal of ash-forming minerals; its weight adds to the cost of transportation, and its evaporation during burning or carbonizing absorbs useful heat. Fine coal that contains more than about 10 percent moisture is notoriously difficult to handle. A problem thus exists for which there are sound practical and economic reasons to seek a solution.

Jan 1, 1961

Low-cost housing, like automobiles, should be appraised in the light not merely of first cost but of upkeep as well. Even more important than the number of miles the family car will go on a gallon of gasoline is the number of days the family home can be kept comfortable on a ton of fuel. A furnace tender who tossed every third shovelful of coal into the ashcan would lose his job promptly, but the effect is the same when homes continue year after year to pour out precious heat through uninsulated roofs and walls, Greater economy in household heating means even more to the national economy than to the individual, especially now that we are preparing for defense. Our fuel resources, although large, should be conserved. If less fuel is used for civilian needs, augmented requirements for defense can be met without unduly increasing the number of men needed at the coal mines and oil ells or adding new producing units that might complicate ultimate readjustment to peacetime conditions when the emergency is past and over-expansion of many industries brings new problems if unnecessary demands for transportation facilities are reduced, public carriers will be able to haul more munitions, and manpower needed for national defense will be released; and by protecting workers from health hazards in their homes additional man-hours of productive effort will be gained. Moreover, reducing the running expenses of houses by proper heat insulation helps home owners to maintain payments on property, and by minimizing foreclosures helps to stabilize the financial structure of the country. In short, here is a situation where the interests of the individual and the Nation are identical and the greatest good for the greatest number is obtained without sacrifice to anyone.

Jan 1, 1941

By S. J. Gasior

A method for destroying the caking properties of bituminous coal was developed by the Bureau of Mines. Coal is treated in a fixed bed by heating through its plastic range under controlled temperatures in mildly oxidative atmospheres composed of inert gas and/or steam containing about 1 volume-percent oxygen. High-volatile A (hvab) and high-volatile B (hvbb) and low-volatile bituminous (lvb) coals in the size range 1/8 to 1-1/2 inches were successfully treated at 0 (atmospheric pressure) to 300 psig in static beds 6 to 18 inches deep. Conditions of treatment depended on the coal and ranged from 80 to 200 minutes at 350° to 510° C. Char produced in this manner from hvab coal was gasified with steam at 800° C and 100 psig in a fixed bed in one series of tests and in other tests was exposed to hydrogen in a dilute co current free-falling-bed system at 750° C and 3,000 psig without agglomerating.

Jan 1, 1965

By T. M. Ruff

A prototype mucking machine designed to operate in narrow-vein stopes was developed by Foster-Miller, Inc., Waltham, MA, under contract with the U.S. Bureau of Mines. The machine, called a compact loader-trammer, or minimucker, was designed to replace slusher muckers in narrow-vein underground mines. The minimucker is a six-wheel-drive, skid-steered, load-haul-dump (LHD) machine that loads muck at the front with a novel slide-bucket system and ejects it out the rear so that the machine does not have to be turned around. To correct deficiencies of the tether-remote-control system, a computer-based, radio-remote-control system was retrofitted to the minimucker. Initial tests indicated a need to assist the operator in guiding the machine in narrow stopes. An automatic guidance system that used ultrasonic ranging sensors and a wall-following algorithm was installed. Additional tests in a simulated test stope showed that these changes improved the operation of the minimucker. The design and functions of the minimucker and its computer-based, remote-control system are reviewed, and an ultrasonic-sensor-based guidance system is described.

Jan 1, 2010

By P. D. Kovscek

The performance of a novel prototype kerf-cutting impact mining machine was evaluated under a cooperative agreement between the U.S. Bureau of Mines and RAMEX Systems, Bellevue, WA, while operating under conditions typical of normal tunnel entry development. Selected operating parameters were monitored concurrently to determine baseline operating conditions and to study relationships between operating parameters. Using the data obtained, the specific energy requirements of the impact mining machine were calculated and compared to specific energy requirements of tunnel boring machines cutting in rock having similar hardness. Tests results indicate that the kerf-cutting impact mining machine can provide a mechanical means for mining very hard rock that cannot be effectively mined using commercially available mechanical excavators.

Jan 1, 2010