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By Tuncel M. Yegulalp

The objective of this study was to categorize mining operations in the stone, and sand and gravel industries into areas of similar ground control functions and define initial factors affecting operational safety in each area, by means of utilizing publicly available data, telephone interviews and on site observations. The findings and recommendations presented in this report are based on the information collected during the two phases of the project. They also contain, in part, the collective qualitative opinion of the operators with respect to government rules and regulations on ground control safety and the implementation of these rules and regulations by government inspectors.

Jan 1, 1981

Control surface stream loss by identifying and selectively sealing water loss zones in stream channels overlying underground mines. Approach Electromagnetic terrain conductivity surveys, coupled with stream gaging, are performed within a stream channel to identify saturated fracture zones associated with loss of stream water. This information is used to target locations for the injection of expandable polyurethane grout. The grout is injected two to three feet beneath the surface of the strcambed, across each loss zone, to seal the fractured strcambed and restore stream flow across the damaged area. How It Works Multiple zones of infiltration (natural and induced) normally exist in stream channels overlying mined areas, causing water handling and/or acid drainage problems in the mines as well as loss of stream flow. It is typically difficult to accurately locate these loss points. Therefore, Conventional methods of stream repair, such as using plastic membranes or clay and rock rip-rapping, are applied to long lengths of a stream channel. The two step approach developed by the Bureau of Mines First quickly and accurately locates loss zones using electromagnetic ground conductivity survey and gaging instruments. Conductivity is measured at fixed spacings (typically 25-50 ft depending on the instrument and desired observation depth), Ground conductivity increases when saturated conditions exist at depth. These apparent flow loss zones are confirmed by gaping, to eliminate possible effects due to unobservable metal debris adjacent to or buried in the stream sediment.

Jan 1, 1991

By E. C. Lane

[The motor gasoline that s being marketed in the United States this summer slightly more volatile then that sold a year ago. This increase in volatility is shown by a general lowering ref the average distillation rang, of about 2°F. During the post 10 years the Bureau of Mines has made semiannual surveys of the gasoline marketed in the United States, the survey just completed being the twentieth in the series. The 12 cities in which samples were collected have beer chosen as representative of the more important marketing territories, as it is obviously impracticable to obtain a sample of every gasoline sold in the entire country.]

Jan 1, 1929

The U.S. Bureau of Mines evaluated water-jet-assisted longwall shearers in full-scale laboratory tests and underground. Both test programs showed that use of high-pressure water did little to reduce the shearer motor energy required to maintain a given cutting rate. However, three other major benefits were achieved with the use of water-jet-assisted cutting. At a pressure of 1,800 psi, respirable dust levels were reduced about 80 pct compared with the dust levels of the conventional water spray system operating at 340 psi. Operating at higher pressures required for water-jet assist also resulted in an increase in the average size of coal cut, which translates into a decrease in product fines. Finally, although no controlled measurements of bit wear as a function of water pressure were made, mine personnel reported that the shearer bits lasted longer when water-jet-assisted cutting was used.

Jan 1, 1989

By Robert L. Lagace

The attention of this group was focussed on four through-the-earth communication systems that are presently of high interest to the U.S. Bureau of Mines; four systems for providing operational/emergency communications on the working sections of coal mines, indeed up to the very face of the section. The systems are: uplink-data, downlink-voice, sidelink-call alert coded page, sidelink-roof bolt voice page. Each of these systems makes use of the mine overburden as the signal transmission medium, as opposed to the guiding wires, cables, and tunnels treated by the operational communications working group. Each of these systems satisfies one or more of the Bureau's objectives for mine communications systems; namely • reliable links for monitoring the mine environment under both operational and emergency conditions. • reliable links for communicating with miners during emergencies. • special links for increasing the efficiency of day-to-day operations of the mine. Each of these systems has been successfully demonstrated on a limited experimental basis, and prototypes of all these systems are installed and operating in the USBM experimental mine in Bruceton, Pa. Each of these systems must now be optimized regarding its performance, and engineered for practical routine application to the working sections of actual operating coal mines, particularly those of the room and pillar type. This optimization and engineering must take place subject to the principal constraints listed by Howard E. Parkinson in his Workshop paper entitled, "Objectives and Constraints of Through-the-Earth Electromagnetic Communications Systems'' and enumerated below. • Depth of Mine Overburden • Overburden Conductivity • Electromagnetic Noise In and Above Mines • Limited In-Mine Electrical Energy (Stationary or Man Carried) During an Emergency • Intrinsic Safety for In-Mine Equipment • Practical and Rugged Equipment for Use Under Both operational/Emergency conditions • Severe Weight Limitations for Man Carried Equipment • Reasonably Low Costs Especially for Man Carried Equipment Part II of this paper provides a brief description of each system, while Part III summarizes the present status of developments related to these systems and some recommendations for future work needed to advance these systems to the practical application stage.

Jan 1, 1973

By J. O. Jones

[Willis Mountain in southeastern Buckingham County is one of several kyanite deposits its central Virginia. It is composed principally of kyanite resulting from metamorphism of siliceous sedimentary beds rich in alumina. The mountain, which trends north-south, is 2 miles long and is topped by a narrow ridge with sleep rugged sides rising to an altitude of 1,160 feet and projecting 500 fast shove the surrounding countryside. Bureau Mines engineers examiner Willis Mountain early in 1949, when bonded concentrations of coarsely crystalline kyanite were observed in the kyanite-quartzite on the northern end of the mountain and in loose boulders on the eastern slope. Commencing in late July 1949, the investigations continued on the Long Mountain segment for 11 months, ended in June 1950. A total of 600 samples from 32 diamond-drill holes, aggregating 3,876 feet of drilling, and from 255 feet of sampling in 3 trenches was assayed for kyanite and ferric oxide.]

Jan 1, 1954

By Andrew K. C. Wong

Hydraulic transport has been considered as one of the most economical methods in transferring granular materials over relatively long distances. In the natural world, it is used to transport basic material required for the support of life; in industry, it is a method widely adopted for handling materials. But the phenomena of hydraulic transport has not yet been thoroughly understood. As most of them are conditioned by a number of hydraulic and mechanical parameters, of which the basic relationships are not fully known, the traditional approach in relating these parameters to the energy requirement is purely empirical in nature. Empirical formulas, such as that proposed by Durand, (1) only give satisfactory results over a selected range of (particle size)/(pipe diameter) ratios and slurry concentration. When the case is more complicated or when new situations arise, the empirical formulas fail to give good predictory results. In fact, most of these formulas are based upon dimensional analysis, where the underlying physical interaction is not explicitly considered. Apart from the loosely related, non-dimensional groups incorporated in the formulas, there is practically no analytical means for modifying the formula so as to enable it to cope with more complex real physical situations. Although it seems quite remote that a complete rigorous solution to this highly complex problem could be generated in the near future, it is generally recognized (2, 3) that research in this area should be directed to more comprehensive studies of the obscure phenomena. In fact, there are a good number of very basic problems such as the effects of gradation and concentration of particles upon

Jan 1, 1972

By O. T. Barrett, R. F. Aberethy, H. N. Cooper, Thomas Fraer, William L. Crentz

"INTRODUCTION The object of the techniques described in this report is to determine the possibilities of separating the components of a raw coal into such grades as may be necessary to recover some exceptionally clean functions for special purposes.To do this commercial gravity methods would require separation at very low specific gravities, entirely outside the range of conventional practice. Hence, a technique has been developed for breaking down cool ample, into very close fractions within the gravity range of the (-lean coal matter as well as for separating it from the refuse and particles.Such data on the fundamental specific-gravity consist of the clean-coal matter will serve to appraise the difficulty of the problem and to chow be accomplished if and when effective methods of making such separations commercially are developed."

May 1, 1945

Develop a curved ray geotomographic program with constraints to counteract non-uniqueness in order to improve the reliability of seismic tomographic imaging of geological structure in mining regions. Background Seismic tomography provides a two-dimensional image (tomographic reconstruction) of the distribution of the seismic velocity in geologic structures using measured travel times of seismic waves crossing the area. It can provide a more complete representation of features be¬tween boreholes than other crosshole processing methods that measure only average properties or borehole logging methods that measure properties only near each borehole. Seismic tomography has many mining applications. They include locating geologic structures of contrasting seismic velocity, detecting fractured regions where the seismic velocity is low, and monitoring solution injected above the water table where the increase in saturation increases the seismic velocity. Thus, tomographic imaging techniques show great promise for detecting and locating geologic hazards that affect the productivity, safety, and environment of mining operations.

Jan 1, 1992

By Erle C. Donaldson

A study of subsurface waste disposal in the United States shows that in eight States a wide variety of industrial wastes are being injected into formations ranging in age from Precambrian to Recent. More than 30 wells ranging in depth from 300 to 12,000 feet are used for waste disposal into subsurface formations which include unconsolidated sand, sandstone, vugular limestone, and fractured gneiss.

Jan 1, 1964

By C. M. Mason

A series of gelatinous permissible explosives was prepared with increasing sodium nitrate content and subjected to an improved technique for evaluating incendivity in coal dust-air and coal dust-gas-air mixtures. Those explosives containing an appreciable amount of sodium nitrate were found to be very hazardous in coal dust-air and coal dust-gas-air mixtures.

Jan 1, 1969

By R. H. Sprute

This report describes Bureau of Mines laboratory test results in electrokinetic dewatering and consolidation of metal-mine tailings. Tailings were placed in 0.3-cubic-foot Plexiglass models, and dc potential was applied until dewatering ceased. Time-oriented measurements of water removal, changes in resistivity, and power consumption were recorded during the dewatering process. Dewatered material was tested for moisture content and density. Equipment and procedures were developed to optimize the method for unclassified mill tailings from a particular mine in the Coeur d'Alene, Idaho, district. Results indicate the method to be highly effective in dewatering and consolidating this material.

Jan 1, 1974

By Harry G. Dosh

Sillimanite, kyanite, and andalusite are aluminum silicates having the same chemical composition (Al2SiO5) and are used in the ceramics industry for the manufacture of high-grade refractories. Natural sillimanite with added corundum or other alumina to just short of mullite (3Al2O3 -2SiO2) proportions is unequalled for jobs wherein strength at high temperatures, resistance to spalling, and resistance to slagging by acid slags are desired. High-grade porcelain ware also requires these minerals. At the same cost, sillimanite would be preferred for most uses, but the lack of any large source of sillimanite bas given economic preference to kyanite or andalusite for special refractories and high-grade porcelain wares. Sillimanite-bearing schists were observed in Spartanburg County, S. C.; as early as 1937 by D. Hoye Eargle, geologist with the U. S. Soil Conservation Service. The mineral was not identified until 1942, when Miss Jewell Glass, of the U. S. Geological Survey, examined several of the deposits. This identification was confirmed in 1943 by Dr. Laurence L. Smith, of the University of South Carolina, when he examined the Spartanburg County deposits and found numerous additional occurrences of sillimanite schist in Greenville County. Subsequent work by the Bureau of Mines and the South Carolina Geological Survey has been responsible for the location of additional sillimanite-rich schist deposits in Spartanburg County. Between October 1, 1948, and November 21, 1948, the Bureau of Mines conducted an exploratory diamond-drilling project on the John Gideon property in the southeastern section of Spartanburg County (fig. 1) and drilled a total of 681.7 feet in six holes. Drilling indicated that the deposit is relatively shallow, as no ore was cut below the zone of weathering.

Jan 1, 1950

Humankind's interest in measurement of human physical strength probably dates to the first humans. At that time, life was truly a struggle in which the fittest survived. To a great extent, fittest meant strongest. Interestingly, current interest in human physical strength in the workplace stems from 1970-1980s vintage research demonstrating that persons with adequate physical strength are less likely to be injured on physically demanding jobs. Survival in many modem workplaces may still be a case of survival of the strongest. There is, however, a flip side to this issue - that persons with limited strength are more likely to be injured on "hard" jobs. To address this problem, we can apply what we know about physical strength to job design. "Hard" jobs can be redesigned to be within the physical strength capability of most people. Since physical strength is important to these jobs, we must find ways to quantify it through testing. This publication concerns human physical strength testing. Its purpose is not to recommend any particular type of testing, but rather to describe the types of testing available and their uses. It is up to each individual user of strength testing to decide which testing technique is most appropriate for his or her particular application. This booklet discusses four types of strength testing: isometric, isoinertial, psychophysical, and isokinetic. Human Strength Before describing the different types of strength measurement, we must define the term "strength" and explain the concept of strength measurement. Strength is defined as the capacity to produce force or torque with voluntary muscle contraction. Maximum strength is defined as the capacity to produce force or torque with a maximum voluntary muscle contraction.(1,2) These definitions include some key words that must be explained. A voluntary muscle contraction is "voluntary." When a person's physical strength is measured, only the effort the person willingly puts forth at the time is measured. Thus, when we test a person's "maximum strength," we are not measuring his or her actual maximum, but some lesser value representing what he or she is comfortable expressing at the time with the existing equipment and environmental conditions. Interestingly, when researchers startled persons being tested (e.g., by setting off a starter's pistol behind them), they have found significant increases in measured strength.(3) It has been hypothesized that the lower strength displayed during normal testing provides a margin of safety against overloading and damaging muscle tissue. The test equipment and the tested person's familiarity with the process also influence the "voluntary" strength output. The interface between the tested person and the test equipment is particularly important. A poorly designed interface induces localized tissue pressures that vary from uncomfortable to painful. In this situation, testers are measuring voluntary discomfort tolerance - not strength. It is important for strength researchers to keep the "voluntary" nature of their data in mind when they are designing their equipment and protocols.

Jan 1, 1998

By William A. Beck

Bauxite was discovered in the Springvale district in 1916. About 16, 000 tons was mined in the period 1916 to 1922, but no bauxite mining has been done since that time. The Bureau of Mines explored for bauxite in the district from September 5 to November 18, 1943. During the life of the project, the Bureau of Mines obtained mineral exploration agreements covering a total of 11,330 acres from 50 property owners. A total of 388 holes were drilled on five of these properties and 164 samples were taken and analyzed. The Springvale bauxite district includes an area of about 30 square miles in the northwestern part of Randolph County, Ga. The village of Springvale is in the west central part of the district, and Cuthbert is 8 miles southeast of it (fig. 1).

Jan 1, 1949

The following methods should be used to protect miners from the adverse health effects of exposure to respirable coal mine dust and respirable crystalline silica: ? Informing workers about hazards ? Establishing written emergency procedures ? Using engineering controls, work practices, and personal protective equipment (including respiratory protection when dust control equipment is being installed, maintained, or repaired) ? Monitoring exposures ? Conducting medical screening and surveillance ? Encouraging smoking cessation ? Maintaining medical records

Jan 1, 1997

By J. B. Clemmer

This report summarizes the results of u laboratory study of the beneficiation of Arkansas bauxite by flotation. Although the investigation is not yet completed, a preliminary retort of the results on several typical bauxites is presented to show the merits rind limitations of flotation for the production of concentrates acceptable to the aluminum industry. It is

Jan 1, 1941

By J. B. Clemmer

This report summarizes the results of u laboratory study of the beneficiation of Arkansas bauxite by flotation. Although the investigation is not yet completed, a preliminary retort of the results on several typical bauxites is presented to show the merits rind. limitations of flotation for the production of concentrates acceptable to the aluminum industry. It is

Jan 1, 1941

By Michael G. Zabetakis

Limits of flammability of normal propyl nitrate (NPN) vapor were investigated at ambient and elevated temperatures. Minimum spontaneous ignition and decomposition temperatures were determined with laboratory apparatus over the pressure range from 0 to 4,000 p.s.i.g. Flame speeds and the detonation susceptibility of NPN vapor were measured at elevated temperatures. Stable detonation was obtained with liquid NPN at elevated temperatures, and the detonation velocity was determined to be between 4,700 and 5,100 m./sec.

Jan 1, 1962

By W. V. Kuster

The investigation described in this report is part of a survey by the Federal Bureau of Mines of the titanium resources of the United States. The purpose of this project was to study a typical coastal deposit of beach sands in the Middle Atlantic States, particularly in the area surrounding the Delmarva Peninsula. The field investigation consisted of a reconnaissance survey of the Eastern Shore of Maryland, followed by surface sampling and drilling of the sands on Assateague Island, off the Atlantic coast of Maryland. The study covered the period January-December 1957. Detailed analyses were made of 5-foot sections of eight drill holes along the Maryland section of the island. The heavy-mineral fraction of these samples was separated by sink-float tests, using acetylene bromide as the heavy liquid. The minerals comprising the heavy fraction were examined microscopically, and mineral counts were made on selected samples.

Jan 1, 1959