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By K. E. Tame

The Bureau of Mines is studying possible modifications in conventional ore-processing methods that will confine and permit controlled disposal of radioactive liquid wastes. Stream and ground water pollution from radio-active nuclides, principally radium 226 and thorium 230, in liquid wastes from uranium mills can be minimized by reusing the waste solution within the mill. Such reuse of waste solution in an acid leach-resin-in-pulp flowsheet was investigated in the laboratory. The process consists of acid leaching for dissolution of the uranium, sand-slime separation and countercurrent decantation washing for recovery of a pregnant slime slurry, and the use of ion-exchange resin for recovery of uranium from the slurry. Reuse of clarified barren effluent for washing in the simulated mill circuit was carried through 55 cycles. Dissolution of uranium from the ore averaged 97.5 percent. Washing efficiency of 99.9 percent was attained when using 4.35 volume tons4 of combined barren effluent and makeup water per ton of ore. Absorption of uranium from the pregnant slime slurry by an ion-exchange resin averaged over 99.9 percent.

Jan 1, 1962

By C. A. Herbert

In summer, when hot, moisture-laden air enters a coal mine in the region east of the Mississippi River, the moisture is likely to condense on the roof and ribs because the incoming air is cooled below its dew point upon contact with the roof, ribs, and floor of the mine passageways. When the roof and ribs become wet owing to this condensation they are said to "sweat." In many mines, as soon as this sweating begins, shale or slate roof that appears solid and strong in winter begins to cut and fall. For a long time most mining men believed (many still believe) that the roof trouble was due to this sweating. However, from observation of conditions in one mine the operators concluded that the trouble was caused by expansion and contraction of the roof due to changes of temperature. This opinion was confirmed by experiments at several mines in cooling the air as it entered the mines. Methods used in these mines for cooling the air are described in this circular. MINE A At mine A the roof gave considerable trouble in the summer, and it was observed that where a spray of water from a leaking dam kept the roof wet and at a uniform temperature no difficulty was experienced with the roof, although it had cut and fallen on either side of that point. From this fact the company officials concluded that changes of temperature in the air rather than moisture caused the trouble and that if the incoming air were cooled to approximately normal strata temperature much of the additional roof trouble experienced during the summer would be overcome.

Jan 1, 1940

As fulfillment of the requirements of Contract H0387019 for the United States Department of the Interior, Bureau of Mines, a complete field kit, for performing on-site determinations of individual employee Time Weighted Average (TWA) exposures to nitrogen dioxide (NO2) and nitric oxide (NO), has been developed by MDA Scientific, Inc. This report provides background information and experimental data validating the use of this kit with confidence to ? 10 percent accuracy.

Jan 1, 1981

By Charles M. Mason

The Bureau of Mines evaluated equipment and procedures for drop-weight testing of explosive liquids as prescribed by Test 4) a widely used method. It was demonstrated that partial ignitions, originally designated as negative results, should be designated positives; it was also shown that wear or erosion of the sample cups and the type of mount used for the apparatus had important effects on the results. Relative sensitivity as measured by Test 4 was found to vary slightly with temperature. The Bureau also designed a fixed 2-kg weight and associated electromagnetic release, which subsequently were incorporated as standard in a revision of Test 4. The original concept that the test involves only adiabatic compression was found to be an oversimplification; an alternate mechanism for the initiation process is proposed in which due consideration is given to the effects of cavitation and microjets.

Jan 1, 1966

By E. D. Gardner

This paper discusses prospecting for lode gold and lists the principal lags and. regulations pertaining to locating; lode claims on public lands. It is a preprint of a part of a bulletin being prepared by the United States Bureau o Mines entitled "Equipping, Developing and Operating Small Gold Mines". The increased interest in gold mining manifested during the past few years (1932-1935) bas stimulated prospecting. Many adventurers have taken to the field to search for now gold deposits. A. large percentage of them have had no previous experience in prospecting for lode gold; this paper has been written with the tope that it might assist these newcomers.

Jan 1, 1935

By Laurel A. Powers

The Bureau of Mines process for recovering Ni and Co from low-grade domestic laterites uses a reduction roast followed by an ammonia, ammo-nium sulfate leach. This investigation examined the waste streams of the process for their potential environmental impact and focused on the laterite residue produced. The U.S. Environmental Protection Agency's extraction procedure (EP) toxicity tests and column leaching showed that leachable metal concentrations would be low enough so that the residue would not be considered a hazardous waste under present definitions. Under nonacid leaching conditions, about the same amount of metal was extracted from laterites as from their residues, and the leachates were similar to water samples from an undisturbed laterite deposit. Washing tests on the laterite residue showed that ammonia and ammonium sulfate concentrations were reduced according to equilibrium stage calculations, resulting in residues that would be acceptable for revegetation. With water washing only, the residue would not be considered a hazardous waste even though significant amounts of Ni and Co were absorbed from entrained leach solution onto the residue. Washing first with fresh leach solution and then with water prevented this absorption and thus improved the overall metal recovery.

Jan 1, 1983

By Roy J. Greenfield

The overall purpose of this research was to improve the understanding of how the post disaster seismic location system works, what determines the signal size, what is the character of the seismic noise, how well the system can detect blows from a trapped miner, and how well the source of the blows can be located. Based on an improved understanding of the system, improvements were suggested in the seismic subarray configuration, and in the system deployment procedures. An important part of this research was to become familiar with the seismic system operation and to work with the Westinghouse Electric Corporation and MSHA personnel to modify and improve the system. To accomplish this we participated in the planning, execution, and data analysis for a number of seismic field tests. Several in-mine field tests were conducted. From these tests the capabilities of an in-mine seismic system were analyzed and specifications were made for designing an operational in-mine system. Several portions of the work done on this grant were covered in previous reports. In particular the capabilities or the presently operational surface based seismic location system has been thoroughly documented by Durkin and Greenfield (1981). Portions of the location procedures and effects of mine openings on seismic signals have also previously been published. These portions or the work will only be summarized in this final report.

Jan 1, 1982

By W. H. Ode

An investigation of standard methods for determining ash in low-rank* coals showed that generally 60 to 95 percent of the total sulfur in the coal is retained in the ash as SO3. This large sulfur retention causes a positive error in the determined mount of ash of as much as 6 percentage points for the coals examined, although it usually is 2 to 3 percentage points for lignites and about 1 for subbituminous coals. Unless the sulfur content is low or unless a correction is made for the SO3 retained, the fixed carbon and oxygen have an equivalent negative error when determined by difference; also other inaccurate analytical values occur when the data are calculated on an ash- free bas is. No simple modification of the ashing procedure was found that would reduce the sulfur retention to a point where its effect on the ash determination would not be significant, Therefore, for accurate analytical work on law-rank coals, the SO3 should be deducted from the determined ash to obtain a "corrected" ash value.

Jan 1, 1962

By H. W. Brandt

A field test was designed to inject a specially formulated two compound epoxy resin into the roof rock ahead of a working face to cement fractures and formation interfaces at the Westmoreland Coal Co., Winding Gulf Div., Eccles No. 5 Mine, Eccles, West Virginia. Five 30 foot long X 2 inch diameter, hold were drilled at an angle of 15° above the plane of roof line front the face of a working entry. The epoxy resin compounds were pumped through a proportioning unit and mixed in-line before being discharged into the drill hole under treatment it injection pressures up to a maximum of 450 psig. When the coal face was advanced an anomalous failure of the roof rock occurred in the treated section. Further testing was suspended until the cause of the failure could he determined. The polymers were tested, under confined conditions, in 2 inch pipe columns. Extreme temperature and pressure (up to 2400 psig) rises were recorded as they cured, It was concluded that this pressure source fractured the rock and caused the roof failure. The entire program was terminated after it was determined that the heat rise and resultant high pressures could not he controlled chemically or mechanically.

Jan 1, 1978

By Albert W. Deurbrouck

This report describes preparation characteristics of significant coalbeds in Tazewell County , Va . In 1961 Tazewell County produced 933,110 tons of clean coal from six coalbeds ; the Lower Banner , Raven , Jawbone , Upper Seaboard , and Pocahontas No. 3 and No. 5. Samples from all of these beds , except the Lower Banner , were included in this study plus a sample from the Pocahontas No. 4 bed . Of the samples collected , only one would require upgrading to be of metallurgical quality . The coals ranged in rank from high- volatile -A to low- volatile bituminous .

Jan 1, 1963

By L. Kaufman

Fifteen boride composites were synthesized by hot pressing and evaluated by physical and incendivity testing as non-sparking tool materials. The incendivity tests, conducted at the U. S. Bureau of Mines, Albany Research Center, compared the boride compo-sites with standard cobalt-bonded tungsten carbide material used for coal cutter bits. Two titanium diboride composites and two zirconium diboride composites out-performed cobalt-bonded tungsten carbide in wear resistance and reduced tendency to cause ignitions. However, three of these candidates exhibited undesirable chipping. The remaining candidate, a TiB2-(Ni, Cu) composite, did not chip, nor did it cause ignitions at levels where cobalt-bonded tungsten carbide tools caused ignitions in the incendivity tests. Thus, this material appears to be a logical candidate for further development.

Jan 1, 1973

By Joseph F. Davies

To gain knowledge of the actual accident hazards present in Kentucky coal mines, reports of fatalities during 1931, 1932, and 1933 have been analyzed and the pertinent factors included in tables, accompanied by some discussion and recommendations for the reduction of accidents from particular causes. ACKNOWLEDGMENT This study was made possible through the cooperation of John F. Daniel, chief of the Kentucky Department of Mines, who made available department records, in addition to the monthly bulletine issued by his office reporting these fatalities.

Jan 1, 1934

By R. W. Stahl

Gas accumulation and dust suspension are the major safety hazards in coal stockpiling and reclaiming operations. This report presents a schedule of safety precautions and plant design features devised by the Bureau of Mines to reduce danger from these and other sources.

Jan 1, 1965

By B. W. Madsen

The Bureau of Mines conducted a large-scale (6.4 t), long-term (2,165 days) test to gain a better understanding of the leaching characteristics of chalcopyritic ores. An ore sample containing 0.77 pct Cu was leached in a fiberglass column by downward percolation of acidified ferric sulfate solutions. Three sets of leaching conditions were investigated: (1) ambient temperature leaching, (2) elevated temperature (50° to 60° C) leaching, and (3) elevated temperature leaching after inoculation with thermophilic bacteria. Leaching at ambient temperature resulted in a copper extraction rate of 0.44 pct per 100 days. Increasing the temperature to 50° to 60° C resulted in decreased activity of natural mesophilic bacteria, and the leaching rate decreased to 0.22 pct per 100 days. The pH was lowered from 2.0 to 1.6, and nutrient solutions that contained thermophilic bacteria were added. This procedure resulted in an increase in the ferric-to-ferrous iron ratio and an increase in the copper leaching rate. However, the increased leaching rate was not sustained, and 120 days after inoculation the bacterial activity declined, the ferrous iron content increased, and the copper leaching rate decreased.

Jan 1, 1983

By B. W. Moore

The U.S. Bureau of Mines investigated the separation of heavy rare-earth elements (REE) in an ion-exchange process. An ion-exchange column consisting of two sections, a loading section and a separation section, provides high levels of REE loading and good REE separation with an expected processing cycle of less than a month, while current ion-exchange technology requires more than 5 months. A different resin is used in each section: sulfonic resin in the loading section and iminodiacetic resin in the separation section. The separation section is further divided into two segments: the first conditioned with NH4 and the second with acid. Erbium is loaded onto both segments of the separation column as a retaining ion. Bands of mixed REB eluting between separated bands of pure REB were recycled directly to the column. Without mixed-band recycle, over 80% of the REE eluted from the column was separated into fractions with 99% purity of each element; with such recycle, the percentage of separated elements can be increased to around 90%.

Jan 1, 2010

By S. J. Gerdemann

In support of its objective to improve mine safety, the Bureau of Mines has searched for better materials and systems to anchor roof bolts. TIlis report describes a study on the effects of mine waters upon accelerated gypsum, one of the materials under consideration. The accelerated gypsuw dissolved at an appreciable rate relative to an assumed 10-yr life span of a roof bolt. Surface orientation, initial ion concentration of a dissolving solution, and flow rate of the solu-tion had substantial effects on the dissolution rate. Factors such as water-cement ratio, accelerator content, wax capsule additions to the gypsum in cartridge-installed bolts, surface area, temperature, and curing duration had little effect. In an actual roof-bolt environment, dissolution will occur in static solutions to the solubility limit of gypsum (~2 giL) and cease, result-ing in minimal damage; but in flows of unsaturated solution as slow as 1 L per month, a loss of up to 10 pct will occur in 2 yr. Since miners cannot readily measure the flow or ion concentration of static-appearing water at every roof-bolt site, all such water must be assumed to be pure and flowing. It is recommended that gypsum-bonded roof bolts be confined to dry roofs only.

Jan 1, 1983

By John J. Sammarco

The U.S. Bureau of Mines is conducting research into computer-assisted mining, which requires investigation of new techniques for development and application of computer-based technologies. Today's technology can require significant effort in software development, as has become evident in the early stages of this Bureau research. Technologies for software automation, such as computer-aided software engineering (CASE), are available. This report explores CASE, its general features, and its importance in software development. Information is presented to assist in selection and application of the variety of CASE tools and methods for automating various stages of software development. When evaluating CASE for use, it is important to examine tools that support an organization's existing methods of software development. Support for existing hardware platforms must also be examined. Merely selecting a "good" CASE tool does not insure success. Thorough evaluation of implementing CASE is also critical. Subjects to evaluate for CASE implementation include organization culture, support from management and end users, training resources, and pilot projects. Organizations that benefit the most from CASE evaluate CASE features with respect to their needs and they properly implement CASE.

Jan 1, 1990

By R. C. Annear

This report describes open, sublevel, and shrinkage stoping at the Greenwood mine, operated by Inland Steel-Co. The iron ore mine is in Marquette County, Mich., about 6 miles southwest of Ishpeming (fig. 1). The Greenwood is one of three active underground hard-ore mines on the Marquette range, the others being the Cliffs-Shaft and the Champion mines. The operation reflects an achievement in exploiting small, difficult-to-mine hard-ore bodies lying beneath a 200-foot overburden of glacial drift, which is partly water bearing. This report can indicate only briefly the efforts of personnel in overcoming adverse conditions in mining more than 2 million tons of ore, 80 percent of which was in lump form, for open-hearth production of steel. Significant data presented include descriptions of the principal mining methods employed, sublevel and shrinkage stoping; percent aged mining costs for the entire year 1957, covering both direct mining costs and general expenses; and performance records in units of labor, power, and supplies.

Jan 1, 1960

By Robert A. Jankowski

"Following passage of the Coal Mine Health and Safety Act of 1969 (Public Law 911173), the Bureau of Mines initiated a research program aimed at controlling respirable dust exposures of coal mine workers. Respirable dust is the dust that gets into, and interacts with, the lungs of those who inhale it. It has long been recognized as a severe health hazard to mine workers. This program has been implemented by a team effort consisting of the Bureau's in-house capabilities, the Generic Center for Respirable Dust, and contractors, as necessary. Over the years, Bureau research has addressed principally three areas:o Compliance with the Federal 2.0 mg/m3 dust standard (1970-76).o Dust control for longwall mining (1976-1983).o More stringent respirable dust standards due to quartz dust (1983-1987).In addition, fundamental studies have been conducted by the Generic Center for Respirable Dust, with emphasis on penetration of dust into the lung. Accomplishments have been significant, but problems remain, as noted later.The Coal Mine Health and Safety Act of 1969, established a 2.0 mg/m3 dust standard for all coal mining operations, underground as well as surface. At the time of enactment of this legislation, the industry was averaging approximately 4.0 mg/m3. The Bureau of Mines respirable dust research program played a significant role in identifying and developing effective technology to allow better compliance with this new standard, thanks to industry implementation and Federal enforcement."

Nov 1, 1988

In 1962 and 1963, two in situ combustion pilot tests were conducted in the shallow Second Venango sand near Reno, Pa. Because of poor oxygen utilization and lack of production response, both tests were considered failures and were terminated. The area was then relatively inactive until late 1966, when a development well drilled near the 1963 test site had surprisingly good production in what was considered to be a pressure-depleted reservoir. Other wells drilled in and around the old thermal pilot areas also came in as good oil producers. This report presents a study of the increased oil production from the Second Venango sand in the Reno area, and the apparent connection of the present production response and the old thermal pilot tests. Apparently combustion occurred in the Second Venango sand after the 1962 and 1963 experiments were terminated and, supported by large volumes of air left in the reservoir after the 1963 test, generated carbon dioxide which helped repressure the formation. This field evidence of combustion warrants another pilot experiment to further explore the use of properly designed in situ combustion techniques in increasing production from the Second Venango sand.

Jan 1, 1971