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By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

2. Preliminary Study - Initial Probing 2. 1 Introduction Initial probing of the mine passage is required prior to the emplacement of the sealant material or deployment of the seal checker system. Factors which are of interest in sealing and checking include a. size and condition of the mine passage b. location of the borehole with respect to the ribs c. the presence of water flows d. the proximity to an intersection The importance of each of these factors depends strongly on the sealant material. Because the sealant material had not been selected at the time of the initial probing study, a broad survey of probing techniques was conducted. The capabilities and limitations of each technique as they applied to probing through the borehole were identified. To facilitate this comparitive evaluation, Table I was prepared which lists all passage conditions which might affect the emplacement of sealant material in the passage. The most satisfactory techniques for observing each condition of interest are listed together with the effects of the observation on the sealing operation. Table II summarizes the environmental conditions likely to be encountered in the passage being probed and the physical

Jan 1, 1973

By L. B. Berger, S. J. Pearce

One phase of Bureau of Mines' work in health and safety is promotion of the use of safe, satisfactory, and reliable respiratory protective. devices. To insure that such devices will be available, the Bureau has established schedules of minimum requirements for self-contained breathing apparatus, gas masks, supplied-air respirators. (hose masks, air-line respirators, and abrasive blasting helmets, hoods, or masks), dispersoid (dust, fume, and mist) respirators, and nonemergency gas respirators (chemical cartridge respirators). Approval tests of self-contained breathing apparatus are conducted by the Safety Branch; approval tests of other types of respiratory protective equipment are conducted by the Health Branch. Both branches are in the Health and Safety Division.

Jun 1, 1950

By C. C. Clark, R. R. Backer, J. D. Vickery

This report presents the results of tests conducted by the U.S. Bureau of Mines to determine the transport characteristics of highly concentrated paste backfill mixes made from dewatered total mine tailings. The slurry concentrations of the mixes were all above 78 pct by weight with slumps ranging from 6.4 to 16.5 cm (2.5 to 6.5in). Laboratory material property tests and full-scale pumping tests were conducted using pipe diameters of 102,128, and 154 mm (4, 5, and 6 in) and a positive-displacement pump. The results indicated that the tested backfill mixes can be successfully transported as a stiff paste and identified the influence of and the interaction among the various mix and system variables.

Jan 1, 1995

By Paul S. Schopf

The results of an experimental investigation into the possible use of medium energy acoustic fields (130 to 140 dB) to precipitate 1 to 10 micron particles is presented. The aerosol was produced with a LeMer generator using oleic acid and nitrogen. The sound field was a sinusoidal standing wave field in an acrylic tube, with light transmission data used for concentration determination. The results showed collection efficiencies of up to 80% on 2 micron particles with a residence time of 11.8 seconds at a sound pressure level of 139 dB re 2x10-5 N/m2. A discussion of the possible turbulent mechanism is made, as well as review and comparison with others? work.

Jan 1, 1972

Crosson and Peters treat the errors that result in miner location due to errors in the overburden earth model used for computing location. A parallel effort by J. Powell of PMSRC is discussed here, where the location method used is that of the Westinghouse location program - "Miner". This location program was tested by Powell by using arrival times generated from the overburden earth model of Table l* rounded to the nearest millisecond. Location computations were then made using 3 geophones at a time. The average location is tabulated for all geophone triplets except when 3 geophones are in line. Geophone arrays were as shown in Tables 2 and 3. The manner in which the test was done is illustrated in Figure 1. I. SUMMARY OF RESULTS The arrival time differences, based on the Table 1 earth model, together with geophone locations based on the array geometries of Tables 2 and 3, were entered into the computer, together with a stated depth of 700 feet and an estimated overburden seismic velocity of 10,000 feet per second. These parameter values were processed by the location program - "Miner". Figure 2 illustrates the interpretation of the plots and data. The tabular data and plots of Table 4 and Figures 3, 4, and 5 illustrate the location error results obtained. These plots indicate that for sources within the array, the errors are considerably less than the measured errors obtained during field tests of the present location system. The possible reasons for this discrepancy are noted in Part Eight (Earth Models).

Jan 1, 1974

By J. P. Coughlin

Gypsum plaster is calcium sulfate hemihydrate (CaS04-1/2H2O). There are two varieties, commonly designated as a and ß. The hydration setting) of this plaster involves the chemical reaction: CaS04?1/2H20(c) + 3/2H20(l) = CaSO4?2H20(c); that is, the hemihydrate combines with water to form the dihydrate. Many substances, when present as impurities, either in the hemihydrate or the water have influenced the rate of the hydration reaction. The objective of the Bureau of Mines work described in this report was to investigate the accelerating or retarding effects of small amounts of dissolved substances and to attempt to classify these effects upon a chemical basis. To eliminate competing effects, the work was conducted separately on the two varieties of hemihydrate; both were in highly pure form. (Commercial plasters usually are a mixture of the hemihydrates, with other substances present as impurities.) As the hydration reaction of each variety of hemihydrate evolves heat in amounts known from previous work, 5,6/ the authors decided to use calorimetric methods to follow the extent of the hydration reaction as a function of time. Two calorimetric methods were employed. One was designed to study the hydration reaction with a large water to plaster ratio and the other with a small water to plaster ratio (to simulate commercial practice in utilizing plaster).

Jan 1, 1959

By Arne Landsberg

Accessory metals, although valuable resources, present possible environmental concern in the smelting of base metals. The Bureau of Mines, U.S. Department of the Interior, has undertaken research to define the chemistry involving these metals. Arsenic in copper smelting is the first to be investigated. Roasting, the first step in many copper smelters, was chosen for initial investigation because of the potential for arsenic removal in this primary process. Simple, static-bed, vaporization experiments were devised to obtain the data in this study. Ancillary transpiration and mass spectrometry were also used to delineate conditions necessary for arsenic volatilization from a roaster feed. For nearly complete arsenic removal, a temperature of 650°-700° C, a reducing atmosphere including carbon monoxide, and a source of sulfur were found to be essential.

Jan 1, 1980

By T. W. Johnson

The Bureau of Mines, in cooperation with the Natural Gas Department of the American Gas Association, has in progress a study or the flow of natural gas through high-pressure transmission lines. A major problem of this study is to compare the deliveries calculated from the gas pipe-line flow formulas commonly used, with the metered deliveries from pipe lines in operation. In order to obtain such comparisons a series of tests has bean made on 25 operating pipe lines in Kansas, Oklahoma, Louisiana, Arkansas, Texas, and California ACKNOWLEDGEMENTS Study of the flow of natural gas through high-pressure transmission lines was made under the general supervision of H. H. Hill, former chief petroleum engineer of the Bureau of. Mines, H. C. Fowler, acting chief petroleum engineer of the Bureau of Mines, N. A. C. Smith, superintendent of the Bureau of Mines Petroleum Experiment Station at Bartlesville, Okla., and T. Brandenthaler, chief of the oil and gas action of the Bartlesville station.

Jan 1, 1929

By Jr. Smith

To investigate the effects of flow geometry on laminar flames, studies are in progress in this laboratory employing Bunsen-type burners with rectangular cross section. Interpretation of these studies requires a determination of the flow velocity at all points of the rectangular cross section for one dimensional steady laminar flow. In addition, values of the velocity gradient at the boundary for such flows are needed in the interpretation of blow-off and flash-back studies with burners of rectangular cross section. The hydrodynamical problem of steady laminar flow of a viscous fluid in channels of rectangular cross section was solved by Stokes. His results have been quoted by Love21 and by Dryden, Murnaghan, and Bateman,§/ and they have been discussed by Boussines and by Paschoud. It may be noted that the steady laminar flow of a viscous fluid in channels of rectangular cross section constitutes a hydrodynamical analogue for the problem of the torsion of an isotropic prism of rectangular cross section.

Jan 1, 1952

By R. T. Johansen

The adverse effects on waterflooding and well-completion methods of clay minerals indigenous to petroleum-production formations recently have received considerable attention. Knowledge of the types and amounts of clay minerals present would allow estimates of the response of such formations to injected or infiltrated water; however, the random distribution of clays in sedimentary formations makes direct evaluation of ?water sensitivity? desirable. A method for the direct evaluation of water sensitivity has been developed, based on measurement of water-vapor adsorption. Correlation of such data with the results of nitrogen-adsorption measurements provides valuable information on the content and properties of clay minerals in sedimentary rocks. The method is relatively simple and has the advantage that it may be used with small, irregularly shaped chips or shale-streaked samples, as well as with typical core samples. Methods previously employed required separating the clay from the rest of the reservoir-sample material and then performing a clay analysis either by X-ray diffraction, differential thermal analysis, liquid permeability, or a combination of these methods (2,3) .3/ This water-vapor-adsorption method requires measuring only a few points on the isotherm to tell whether or not the sample is water sensitive. The goal of these measurements is not to determine the type or amount of clay present, but what will be its sensitivity to flood water. This method gives a direct means of solving this problem.

Jan 1, 1958

By J. H. Holden, C. C. Shale, G. R. Strimbeck, W. S. Bowie

Electrical characteristics of positive corona are presented for air in a 2 - in - diam electrostatic precipitator operating under dynamic conditions at temperatures of 600 ° to 1,500 ° F and pressures of 0 to 80 psig . Results show that current - voltage relationships depend solely on air density . Comparison of data on positive corona with previously published data on negative corona demonstrates a higher sparkover voltage and a wider range of operability for positive corona at temperatures above 375 ° F. The possibility of achieving higher voltages with positive polarity as indicated by these experiments implies several advantages for the use of positive corona in precipitators to allow better removal of suspended material from hot gases . Based on the physics of an ion in an electrical field , a theoretical equation is derived to define current - voltage characteristics of positive corona in terms of air density . Constants for the equation are evaluated from Calculated current - voltage values at different air densities agree reasonably well with experimental data .

Jan 1, 1964

By J. A. Stampe

In connection with its investigations of strategic minerals in the United States, the Bureau of Mines ran magnetic surveys totaling more than 533,000 linear feet at 30 deposits of magnetite in northern New Jersey. These deposits occur in a belt of granitic gneiss and in limited areas of limestone. The ore consists of magnetite accompanied by score of the following minerals: Hornblende, augite, apatite, feldspar, biotite, calcite, garnet and pyrolusite. Results of these investigations are being presented in two reports of which this is the second. The first paper, Certain. Magnetite Deposits in New Jersey, by A. L. Neumann and McHenry Mosier, was issued in April 1948 as Report of Investigations 4225.

Jan 1, 1949

By R. R. Wells

An important activity of the Bureau of Mines is the continual search for new sources of minerals. As a part of the investigation of strategic mineral deposits in the United States, samples of mercury ores were submitted to the Ore Dressing sections of the Salt Lake City and Albany stations for metallurgical testing. This paper gives data summarizing the results obtained from laboratory beneficiation studies of mercury ore samples submitted during the period 1941 to 1947. Ores tested included three from Jackson County, Oreg., one from Valley County, Idaho, one from Storey County, Nev., and one from Sonoma County, Calif. In general, the ores from Oregon were not amenable to concentration by flotation because of intimate association of cinnabar with other minerals or because of extremely low grade. One Oregon ore was amenable to direct distillation provided lime was added to reduce corrosion of the retort.

Jan 1, 1950

By D. K. Ingram, G. L. Mowrey, T. R. Rehak

Problem: Blasting is a hazardous component of surface mining. Serious injuries and fatalities result from improper judgement or practice during rock blasting. This paper describes several fatal injury case studies, analyzes causative factors, and emphasizes preventive measures. Method: This study examines publications by MSHA, USGS, and other authors. The primary source of information was MSHA’s injury-related publications. Results: During the 21-yearperiod from 1978 to 1998, the mean yearly explosive-related injuries (fatal and nonfatal) for surface coal mines was 8.86 (95% CI: 6.38 -11.33), and for surface metal/nonmetal mines 10.76(95% CI: 8.39 - 13.14). Flyrock and lack of blast area security accounted for 68.2% of these injuries. This paper reviews several case studies of fatal injuries. Case studies indicate that the causative factors for fatal injuries are primarily personal and task-related and to some extent environmental. A reduction in the annual injuries in surface coal mines was observed during the ten-year period of 1989 - 1998 [5.80 (95% CI: 2.71 - 8.89) compared to the previous ten-year period of 1979 - 1988 [10.90 (95% CI: 7.77 - 14.14)]. However, such reduction was not noticed in the metal/nonmetal sector, i.e., 9.30 (95% CI: 6.84 - 11.76) for the period 1989-1998compared with 11.00 (95% CI: 7.11 - 14.89) for the period 1979-1988. Discussion: A multifaceted injury prevention approach consisting of behavioral/educational, administrative/regulatory, and engineering interventions merits consideration. Impact on industry: The mining community, especially the blasters, will find useful information on causative factors and preventive measures to mitigate injuries due to flyrock and lack of blast area security in surface blasting. Discussion of case studies during safety meetings will help to mitigate fatal injuries and derive important payoffs in terms of lower risks and costs of injuries.

By R. A. Beall

As part of an ongoing program to develop high-quality materials with improved performance and service lives, and to conserve critical minerals, Bureau of Mines, U.S. Department of the Interior, researchers studied the process of hot-rolling metals, alloys, and composites in vacuum. First, a comprehensive review of the literature is presented, including the advantages and disadvantages of using vacuum. Next, details of hot-rolling titanium, chromium, and molybdenum-iron bimetal are given. Finally, the design of new equipment is described. At this time, it is uncertain whether hot-rolling metals in vacuum will gain commercial acceptance in the future.

Jan 1, 1979

By John D. Prater

Thallium is one of the rarer metals that has come into commercial importance in recent years. Although the element was first reported by Crookes in seleniferous deposits in lead chambers of a sulfuric acid plant in the Harz Mountains of Germany, it had no commercial significance until about 190O because of the high cost of extraction. Thallium occurs widely in the earth's crust but is found in such low concentrations that it is recovered only as a byproduct from processing other elements. There are no domestic ores of thallium; the entire output in this country is supplied by the American Smelting & Refining Co. as a byproduct of its cadmium operations at Globe, Colo. Thallium also is recovered from the flue dusts of sulfuric acid works in which thallium-bearing materials are used and as a byproduct of the lithopone industry. This paper describes methods for recovery of thallium from 'white arsenic" and lead Cottrell-precipitator dust of the American Smelting & Refining Co., lead smelter, Murray, Utah. Owing to an enlarged market for thallium because of increased military requirements and expanded peacetime uses, the Salt Lake Station of the Bureau of Mines surveyed the occurrence of thallium in ores, concentrates, and smelter products from all parts of the nation and found the most promising source was certain smelter products of the American Smelting & Refining Co. plant, Murray, Utah. Much of the thallium was being lost in marketed arsenic products; therefore, this investigation was undertaken to develop methods for recovering the thallium.

Jan 1, 1952

By A. W. Khair, M. Ahmad

"Bit wear has been proven to have a significant effect on respirable dust generation in coal cutting system. The mechanism of bit wear can be adhesion, abrasion. oxidation, or diffusion. depending on cutting conditions. This paper presents a portion of an extensive ongoing series of studies to better understand the principles of bit wear and dust generation. Used bits collected from underground coal mines were analyzed to identify the basic principle of bit wear in coal and rock cutting. Distribution of weight loss and conical height loss of worn bits were studied and bit wear was divided into four stages according to weight loss. Utilizing these worn bits, Laboratory experiments have been carried out to study the effects of bit wear on coal cutting system and respirable dust generation. An Automated Rotary Coal Cutting Simulator was use to perform the experiments. Acoustic emission monitoring is applied to study the effect of bit wear on fracture formation and dust generation. INTRODUCTIONContinuous miners were introduced in the 1950’s and became the major equipment in underground coal production. Now the larger production in the coal industry has increased the demand for continuous miners and their use. It is well known that serious dust problem is also introduced with the use of continuous miners, especially with recent increase in productivity. On the other hand, legal restrictions are made ·more strict by the Mine Health & Safety Administration for the respirable dust generated by the continuous miners to prevent coal workers from incidence of pneumoconiosis. The incidence of pneumoconiosis depends on dust concentration, exposure time, and physical properties of dust. Of them, dust concentration is the best parameter for the assessment of the risk of pneumoconiosis. Although a lot of research work has been done to reduce dust concentration substantially, some areas are still required further investigation to meet the strict regulations. One of the areas is about bit wear and dust generation. In this area, the principles of bit wear and effect of bit wear on dust generation are major concerns."

Mar 1, 1992

By L. A. Haas

The U.S. Department of the Interior, Bureau of Mines, is conducting laboratory-scale research to determine the leaching conditions required with sulfuric acid for extracting base metal from a matte with a copper-to-nicke1 ratio of 6 to 1. The matte (61.2 pct Cu, 9.7 pct Ni, 3.3 pct Fe, 21 pct S, and about 5 oz of precious metals per ton) was prepared from Duluth Complex (Minnesota) ore by smelting a bulk sulfide flotation concentrate. The matte was pre leached at atmospheric pressure to selectively extract 20 pct of the nickel, and the undissolved solids were referred to as the matte residue. Autoclave leaching of the matte residue extracted over 95 pct of the nickel, copper, and iron. The remaining leach residue in the autoclave contained over 100 oz of precious metals per ton. The leaching conditions required were matte grind of greater than 98 pct minus 325 mesh, pulp concentration of 50 g/1, total pressure of 100 psig with oxygen at 150° C or 400 psig with air at 180° C, 50 g/1 H2S04, 700 rpm agitator speed, and 6 hours of leaching time. The leaching time was decreased to 2 hours by increasing the agitator speed to 1,300 rpm. Sulfuric acid concentration greater than 50 g/1 did not appreciably enhance the base metal extraction, but with less acid, residues with higher iron concentrations were obtained. Supersaturation of the liquor was prevented at 150° C by using a 1ixiviant that contained 30 g/l Ni and 20 g/1 Cu.

Jan 1, 1979

By Masami Hayashi

Cost evaluations were made for five processes for producing 100,000 tons of electrorefined copper per year from a chalcopyrite concentrate. The processes were (1) conventional smelting with all furnace gases vented to the atmosphere; (2) conventional smelting with converter gases routed to an acid plant and reverberatory gases vented to the atmosphere; (3) conventional smelting with converter gases routed to an acid plant and reverberatory gases to a citrate system plant; (4) conventional smelting with all furnace gases routed to a citrate system plant; and (5) a modified smelting process in which the concentrate is roasted before being charged to the reverberatory furnace, with roaster and converter gases routed to an acid plant. The total fixed capital costs of the plants were estimated as (1) $56.7 million, (2) $77.4 million, (3) $87.2 million, (4) $73.9 million, and (5) $77.0 million, respectively. Total S02 removal from stack gases as sulfuric acid or sulfur for each process was (1) none, (2) 66 percent, (3) 99 percent, (4) 98 percent, and (5) 78 percent. Assuming no credit for byproduct sulfur or sulfuric acid, total operating costs per pound of electro-refined copper produced were estimated as (1) $0.081, (2) $0.103, (3) $0.119, (4) $0.111, and (5) $0.103, respectively.

Jan 1, 1974

By G. W. Elger

This report describes pilot-plant studies and an economic evaluation of a process developed by the Federal Bureau of Mines, Albany Metallurgy Research Center, to produce synthetic rutile from a rock-type ilmenite concentrate. In this process, ilmenite blended with coke and lime is smelted in an electric arc furnace to separate most of the iron as salable pig iron and to form a titania-enriched slag of low iron content, which is treated with oxygen and titanium pyrophosphate. The titanium oxides are converted to crystalline rutile; the phosphate glass contains most of the associated impurities. The treated slag is ground and leached with sulfuric acid to liberate rutile crystals, which are concentrated by physical methods. In pilot testing conducted to obtain data for a cost estimation, a synthesized product containing about 88 wt-pct TiO2 and less than 2 pct FeO was extracted from a rock-type ilmenite concentrate containing about 45 wt-pct TiO2. The estimated fixed capital cost (on a mid-1975 basis) of a plant producing 500 tpd of synthetic rutile is $28,290,100. Based on 330 operating days per year, the estimated operating cost for this process is $351 per ton of synthetic rutile. The estimated selling price of synthetic rutile made from rock-type ilmenite is $344 per ton, based on a credit of $160 per ton of pig iron and a 20 pct interest rate of return on investment after taxes.

Jan 1, 1976