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By A. W. Maynard

Simple chemical spot tests for the identification of major alloying elements in aluminum-base alloys are described. The tests are suitable for use by nontechnical personnel working outside a laboratory. Tests for zinc, copper, manganese, and magnesium employ electrographic sampling methods and sample papers. Use of electrographic sampling in a test for magnesium in aluminum is made possible by using glass fiber filter paper. Differentiations between magnesium and magnesium-silicon alloys of aluminum and between aluminum-base and magnesium-base alloys are made by direct chemical solution tests. Description of a device for obtaining reliable electrographic samples is included. A sequence of testing for identification by alloy groups is given.

Jan 1, 1971

By H. Carroll

An ozone detector was built and evaluated for its applicability in smog-chamber studies. The detection method is based on the reaction of ozone with ethylene and the measurement of resultant chemiluminescence. In the first phase of evaluation, the detector's response to ozone was studied as a function of several instrument parameters, and optimum conditions were defined for the maximum and most stable responses to ozone. In subsequent evaluations, the method was checked for sensitivity, precision, and interferences and was compared with two alternative methods. Results showed the chemiluminescence method to be acceptably sensitive and precise for smog-chamber studies and superior to the Mast ozone meter and KI (colorimetric 1 percent neutral-potassium iodide method) methods in that it is specific for ozone.

Jan 1, 1972

Provide a low-maintenance, reliable means of generating bubbles and controlling bubble size for column flotation. Approach Commercial sparger systems used in flotation columns to process minerals provide only limited means of controlling the size of bubbles generated and the rate of air injection. Generally, these limitations are a detriment to flotation performance, particularly in recovering coarse or fine mineral particles. In addition, conventional bubble generation systems require frequent maintenance, often requiring shut-down of the column itself for repairs. To permit greater control of the bubble size generated in the flotation column and to eliminate the counter-productive problems associated with the operation of current air sparger systems, the Bureau of Mines investigated alternative methods for generating bubbles. Based on the investigation, an external bubble generation system was designed, developed, and laboratory and commercially tested.

Jan 1, 1987

Establish a procedure for reliably determining cation exchange parameters at an in situ mining site. The Problem Predicting the movement rates of pollutants from waste disposal sites requires reliable measurements of cation exchange parameters since cation exchange can retard pollutant movement. Reliable measurements of these parameters are also required for predicting the length of time needed to restore groundwater quality after in situ mining. Cation exchange is otten the controlling mechanism for the replacement of leach solution cations by the cations in the returning ground-water. Unfortunately, laboratory measurements using core samples are of minimal reliability. The uneven clay distribution at most sites produces a high variability in laboratory results. In addition the flow pattern in the laboratory tests is different from that in the field. Approach Bureau of Mines research has developed a field-test procedure that is quick and yields reliable and representative data. A corresponding data analysis procedure was also established in order to verify the' applicability of the computer simulation model of cation exchange used in the analysis, and of the general analysis procedure, with actual field data.

Jan 1, 1986

By A. Wahab Khair, Richard D. Begley

"This paper presents results of destructive tests performed on rectangular coal specimen under the influence of two vertical and simultaneous wedge indentation forces. Several wedge designs and spacings were utilized in compression tests. The objective of these experiments was to qualitatively monitor the effect of different wedge designs and spacings on the stress distribution within the coal specimen.Coal samples from the Waynesburg coal seam were cut and trimmed to cubical dimensions of approximately 5 X 10 X 20 cm. These specimen were subjected to parallel compressive forces through two vertically applied wedge indentors. Loading was achieved with a hydraulic hand pump in order to facilitate interferogram construction. The load increments were limited due to the sensitivity of the holographic interferometric technique (holometry) in measuring small displacements; therefore, interferograms were taken only during similar increments in order to allow for a qualitative comparison between different wedge design and spacings. In some cases, interferograms were taken immediately before and after failure of the specimen.Introduction Failure Modes Three distinct modes of failure occur when geologic materials are subjected to wedge indentation forces. As shown in Figure 1, a crushed zone is located immediately adjacent to the indentor while chipping can occur if the fractures initiated in the crushed zone extend upwards to the free surface.. The third failure mode is a zone of intricate frac¬tures located between the crushed zone and the chipping zone. Several experiments have been conducted over the years to better understand crater formation and stress distribution within geologic materials under the influence of an indentor. Generally speaking, crack initiation and propogation observed in these experi¬ments correlate fairly well with wedge indentation theory; however, the nature of the .fractures is greatly influenced by different material properties such as grain size and cleavage planes. In other words, a wide range of behavior has been found in different rocks subjected to wedge penetration. For example, it has been observed that some rocks are merely crushed and indented while others are more prone to cracking and chip formation. Therefore, the development or nondevelopment of chips depends mostly on wedge geometry, rock type and depth of penetration. This work is part of the study associated with opti¬mization of cutting parameters, which is best modeled by using brittle materials and subjecting them to rigid wedge penetration tests."

Jun 1, 1988

By A. J. Farstad, R. F. Kehrman

Characteristics of metal/non metal mines were evaluated to determine the suitability of applying the U.S. Bureau of Mines electromagnetic location system to the problem of locating trapped driers in metal/non metal mines. Statistical distributions of mine depths and overburden conductivities show that the existing USBM EM system is inadequate for most metal/non metal mines. Alternate approaches to trapped miner location in deep mines were identified and subsequent field tests were conducted at six (6) mines to evaluate their feasibility. The approach considered to be the most promising is one which utilizes the existing manpack transmitting system, modified slightly for a dual frequency output, in conjunction with a sophisticated signal processing receiver on the surface. The main advantage of staying with a "through the earth" approach is that the underground equipment can be kept simple, easily maintained, light- weight and inexpensive.

Jan 1, 1979

By J. C. Hartley

The most important single operation in mining is the ventilation of underground areas in a manner conducive to the health and safety of employees. Adequate volumes of pure air must be supplied at the working faces, along the haulageways, and wherever men work, so as to dilute and carry away the methane liberated from the coal and adjoining strata, noxious gases evolved by the use of explosives, and the carbon dioxide exhaled by men and formed by oxidation of carbonaceous material, as well as any other gases, and also dusts which may be found in mine workings. A sufficient quantity of air must also sweep abandoned or worked-out areas of the mine to prevent the accumulation of gases, where sealing methods are not utilized to isolate old workings. Air, in a quantity adequate to meet the needs of the particular mine to which it is applied, is necessary, and supplying it can be made very expensive through failure to observe good practices in its direction and apportionment." Leaky stoppings, doors, and overcasts rob the working faces of air and add to the ventilating cost by burdening the fans with fugitive air,

Jan 1, 1944

Although haulage truck collisions account for only a small percentage of haulage accidents, the likelihood of severe injury, or even death is very high when such a collision does occur. Most rear-end collisions also result in considerable equipment damage, creating a need for expensive repairs. To improve collision protection, some southwestern surface mines have, for several years, been fabricating and using extended bumpers. In cooperation with these mines, the Bureau of Mines has worked to improve this technology by evaluating the structural requiremnts of extended bumpers. How Extended Bumpers Help The Bureau found that when one large rear-dump haulage truck collides with the rear of another an extended bumper protects the driver of the vehicle that is struck by dissipating the impact energy into the rear tires and pushing the whole vehicle forward. An extended bumper also prevents the box on the truck that is hit from penetrating the cab of the other truck-a typical and serious collision hazard. A further advantage derives from the wide design of the extended bumper which helps prevent damage to truck ladders, thereby minimizing any entry or exit problems. Extended bumpers also provide safe work platforms at the front of large haulage vehicles.

Jan 1, 1984

By R. Karl Zipf

A method is presented for creating realistic numerical models for practical coal mine ground control. The method includes procedures to collect the necessary mechanical input parameters from a geologic core log, procedures to set up a model, and procedures to interpret calculation results. The input parameters come from a detailed geologic core log and extensive point load tests of estimate rock layer strength. A suite of material property input parameters is proposed that allows the user to go from core log to numerical model inputs. Rock bolt anchorage properties are also linked to the material properties of each geologic layer in the model. Following this procedure leads to very realistic calculations of the rock failure process and rock support system behavior. These calculations in turn enable realistic comparison of the effectiveness of alternative rock support systems.

Jan 5, 2007

This Information Circular from the National Institute for Occupational Safety and Health (NIOSH) documents and supplements the information presented in a series of workshops held during 2002 and 2003. The primary intended audience consists of all who are involved in developing and conducting miners? training. According to the Mine Safety and Health Administration (MSHA), mine operators reported 240,000 full-time equivalent workers and independent contractors reported 42,000 full-time equivalent workers working on mine property during the year 2000. Unfortunately, these workers have a relatively high risk of suffering serious work-related injuries and illnesses. The mining industry has the highest rate of occupational fatalities among all U.S. industries. The fatality rate is 30 deaths per 100,000 workers compared to 4.6 for all private industry(Morbidity and Mortality Week Report, 2001; NIOSH, 2002).Compared to workers in other industries, miners also have a relatively high rate of nonfatal lost-time injuries, and their injuries tend to be more severe (Bureau of Labor Statistics, 1999). Many miners are also exposed to significant health hazards, including coal and silica dust, diesel exhaust, and noise. More than 1000 U.S. miners die of lung disease each year(NIOSH, 1999).

Jan 1, 2002

By A. D. Mah

Thermodynamic data on compounds of arsenic and sulfur were critically evaluated by the Bureau of Mines. Changes of standard enthalpy and Gibbs energy, and logarithms of the equilibrium constants were tabulated as a function of temperature for reactions involving these compounds.

Jan 1, 1982

By R. F. Abernethy

A chemical method of determining microgram quantities of arsenic in coal was investigated by the Bureau of Mines to supplement a semiquantitative spectrographic method of determining arsenic in coal ash. In accordance with a method recommended by the International Organization for Standardization, 1-gram samples of coal are decomposed by wet oxidation with boiling sulfuric acid (H2S04) and nitric acid (HN03) to remove the organic matter. After heating to fumes of SO3 to remove HN03, the arsenic is separated as arsine by the action of zinc in H2S04 solution. The arsine is absorbed in dilute iodine solution in which the arsenic is determined colorimetrically by the molybdenum-blue reaction. Two modifications of the method for obtaining the arsenic in solution, in addition to the wet oxidation method, give satisfactory results. The modifications are (1) furnace ashing with MgO added to the coal, followed by treatment with H2S04, and (2) extraction of arsenic from the coal by dilute HNO3 without ashing. Float-and sink-tests show that arsenic is associated mainly with mineral matter in the three coals examined. High-temperature ashing tests show that very little arsenic is volatilized from coal ash below 1,000° C, but it is virtually all removed from the ash at 1,300° C.

Jan 1, 1968

By H. O. McDonald

Solutions containing Cr6+ and sulfuric acid are used in a number of surface-finishing operations. Substantial quantities of chromium and copper are lost and pollution problems are created when the spent solutions are discarded. To minimize the undesirable environmental effects while improving secondary resource recovery technology, the Bureau of Mines is conducting research to detoxify and recover metals from these solutions. Spent etchants are treated to remove copper and reduce Cr6+ to Cr 3+ in an electrolytic cell. The anodes and cathodes are granulated coke. The spent solution is continuously pumped through the electrodes. Hexavalent chromium is reduced to trivalent chromium, and copper is recovered at the cathode. Reoxidation of Cr3+ at the anode was not observed. The removal and recovery of copper reduction of Cr6+ lessen chemical demand and increase efficiency in waste in treatment operations associated with the use of these solutions.

Jan 1, 1980

Prevent collisions between large mine-haulage trucks and smaller vehicles parked in areas not visible to the haulage-truck operator, Approach Two electronic systems were developed to detect the presence of vehicles in the blind areas of a parked haulage truck. The systems can warn haulage truck operators of presence of vehicles that are blocked from view. The systems do not apply for trucks in travel. How It Works The systems use electronic transmitting techniques-one system is based on low-frequency radio waves and the other on very-high-frequency radio waves. Each system requires that a signal transmitter be mounted on the smaller vehicle to be detected. Continuous signals from this transmitter are sensed by receiving antennas mounted on the right front and rear of the large haulage truck. Upon receiving a signal, the receiver energizes warning lights and a buzzer in the cab of the haulage truck, alerting the operator to a possible collision hazard. Detection distance is adjustable, depending upon the size of the haulage truck, but a minimum of 30 feet was the design goal.

Jan 1, 1990

Eliminate accidental tramming of a cleanup tractor. Approach A switch was installed in the operator's seat cushion to pre-vent the cleanup tractor from tramming without an operator in the driver's seat. How It Works The operator must be seated, and the Forward/Reverse Switch (that controls tramming direction) must pass through the NEUTRAL position before the vehicle will tram. See Figure 1. A pressure-sensitive seat cushion switch, a solid-state relay, and a double-contact relay were added to the control circuitry of an S & S BMUAT -88 cleanup tractor to create this tramming interlock. The weight of the operator on the cushion closes the seat cushion switch (Figure 2, A). This activates the solid-state relay (B), which completes the initial circuitry. Moving the For- ward/Reverse Switch (C) to NEUTRAL energizes the coil in the double-contact relay (D) and closes both contacts. One contact completes a sustaining circuit which keeps the double-contact relay energized. The second contact transfers power to the remaining contacts within the Forward/ Reverse Switch. These circuits are shown in greater de- tail in Figure 2.

Jan 1, 1978

By David C. Oyler

The Bureau of Mines is cooperating with the U.S. Department of Energy in a directional degasification project at the Emerald mine near Waynesburg, Pa. This project is designed to combine the highly successful underground horizontal degasification technology with surface drilling methods. The objective of this program is to demonstrate that directional drilling can be used as a technique for degasifying coalbeds ahead of mining to reduce the hazards of methane-air explosions in coal mines. The directional hole at the Emerald mine is designed to start vertically and enter the Pittsburgh coalbed horizontally. A 3-inch-pilot hole entered the Pittsburgh coalbed at a vertical depth of 999 feet. The hole will be reamed to 8-3/4 inches in diameter, and 5-1/2-inch casing will be cemented in place. Three individual 3-inch-diameter, 3,000-foot horizontal gas collection holes will be drilled into the coalbed in a "bird foot" pattern. A corehole and vertical dewatering hole have been completed at the anticipated coalbed intercept. The dewatering hole was drilled to 130 feet below the Pittsburgh coalbed, a depth of 900 feet, and 880 feet of 7-inch-OD casing was cemented in place. Seven vertical holes for monitoring the extent and progress of degasification have been drilled within the horizontal drilling area.

Jan 1, 1979

By G. W. Jones

[A survey of the literature relating to ignition temperatures of acetylene-air and acetylene-oxygen mixtures reveals rather wide disagreement in the reported results. In some instances the ignition temperatures of acetylene-air mixtures were reported to be lower then those of acetylene-oxygen mixtures, which is contrary to experience with other combustibles. To clear up some of the reported discrepancies, the authors have investigated the ignition temperatures of acetylene both in air and oxygen, and their results are presented in this report.]

Jan 1, 1941

By Kenneth P. Klouse

The current rulemaking on mine illumination makes it necessary for mine personnel to have an understanding of the behavior of light. They must be able to understand many terms that are new to the industry and must be familiar with the use of various types of photometers. With this knowledge, the enforcement criteria for mines can be understood and compliance can be maintained.

Jan 1, 1976

By Fred C. Turin, Sean Gallagher, Kim M. Cornelius, William J. Wiehagen

An important part of initiating a site-wide ergonomics evaluation process is prioritizing jobs to be analyzed. While injury data is important, other factors such as worker discomfort and physical exertion requirements, should be considered. This paper describes the use of four sources of data (injury records, the Nordic Standardized Musculoskeletal Questionnaire, supervisor interviews, and management concerns) to prioritize jobs for ergonomic analysis. The approach described integrates the four sources using a decision matrix to prioritize jobs for ergonomics analysis.

By Gordon E. Fletcher

This Bureau of Mines report outlines the atomic absorption analysis of oilfield brines for barium, calcium, copper, iron, lead lithium, magnesium, manganese, potassium, sodium, strontium, and zinc, using the method of additions. The advantages of using atomic absorption are discussed. The method of additions was chosen to overcome large matrix interferences usually found in brines; techniques of overcoming chemical, ionization, and background interferences are also described. The method was used to analyze several hundred oilfield brines and found to be rapid and reasonably accurate. A solvent extraction method was used to concentrate lead, copper, zinc, and iron in low-level samples.

Jan 1, 1974