Search Documents

By R. J. Gajan

As part of its research program on secondary metal refining, the Federal Bureau of Mines has developed a fast method for determining aluminum, iron, copper, cadmium, and lead in zinc-base alloys. The new method is intended for use by trained technicians in laboratories with inexpensive equipment. It can be used either in the analytical laboratories of the many small plants that are characteristic of the secondary metals industry or in laboratories engaged in basic research to improve refining processes. A complete analysis for the foregoing elements can be made in less than 3 hours from a single sample in solution. The method is especially helpful when a small amount of sample is available. Aluminum and iron are determined spectrophotometrically and the other elements polarographically. The new method is now being used for control analysis in metallurgical research, and the results compare favorably with previously used spectrographic methods. Luke and Braun4/ described a photometric method for the determination of aluminum in zinc diecasting alloys in which the aluminum was complexed with Aluminon reagent (ammonium salt of aurintricarboxylic acid), forming a red lake. An adaptation of this method was used for determining aluminum. Beers law is obeyed between 0.01 and 0.06 milligram of aluminum.

Jan 1, 1961

By A. F. Colombo

The western Mesabi range nonmagnetic taconites containing about 34 percent Fe were evaluated by the Bureau of Mines in a 900-pound-per-hour pilot plant employing a selective flocculation-desliming-cationic flotation technique. The flotation step was a reverse flotation process and involved the flotation of the gangue minerals. The objective of the research was to increase the availability of domestic raw materials for the iron and steel industry. The beneficiated ores yielded concentrates containing 62 to 64 percent Fe and less than 5.5 percent Si02 with accompanying iron recoveries that averaged about 75 percent. Comparable flotation results were obtained with either fresh or 80 to 90 percent reclaimed water. Recycled waters having turbidities as high as 5,000 ppm Si02 did not affect the flotation process. Reclaimed waters containing residual calcium contents of less than 10 ppm gave better flotation concentrates than those containing 15 ppm.

Jan 1, 1976

By A. R. Rule

This report describes preliminary studies by the Bureau of Mines to develop a procedure for extracting the fluorine from low-grade fluorspar ores in which the CaF2 particles are finely locked in the calcite matrix. A combination of flotation beneficiation and pyrohydrolysis is applied to recover and to liberate the fluorine. Flotation of a finely locked high-calcite fluorspar ore containing only 11.7 pct CaF2 recovered over 92 pct of the fluorspar at a grade of 51 to 52 pct CaF2. Pyrohydrolysis of the flotation concentrate liberated nearly 90 pct of the fluorine as aqueous HF. By this procedure over 80 pct of the fluorine contained in the original ore was extracted.

Jan 1, 1974

By John P. Coughlin

The Bureau of fines has tested a portable microseismic processor recorder at the Galena Mine, Wallace, ID, both in an environmentally controlled enclosure and, with minimal protection, in a working area of the mine. In both trials the device demonstrated effective and reliable data acquisition capabilities.

Jan 1, 1985

By Webster S. Anderson

Bureau of Mines planer mining tests on the phosphate bed of the Douglas mine, near Drummond, Mont., indicated that a competent bed with a Mohs' scale hardness of 3 to 4 cannot be mined economically with the planer. Although planer mining was feasible where the bed was fractured enough for a 4-inch depth of cut to be consistently maintained, the depth of cut in the competent beds at the Douglas mine did not exceed 0.5 inch. Average production rates were 0.15 ton per minute and 9 tons per man-shift.

Jan 1, 1966

By D. S. Kingery

Owing to changes in State mining laws, the Maryland Bureau of Mines requires all mine foremen to have a thorough, practical knowledge of mine gases and the limitations and use of recognized gas-detecting devices. This requirement involves immediate training of second-grade mine foremen and aspirants to qualify them for certification under the new law. Cooperation of the Federal Bureau of Mines was requested, and a plan for training was discussed and adopted. The methods used in Maryland aroused unusual interest by participating individuals, and the final results were very satisfactory. Consequently, it is thought that this plan will be of interest and assistance to other organizations faced with the need for such training.

Jan 1, 1952

By R. L. Grayson, W. E. Wallace, J. W. Stephens, M. D. Attfield, P. S. Brower, V. Vallyathan, M. J. Keane, J. C. Harrison

Pure respirable quartz is a known pathogenic agent for lung disease. However, for mixed dusts, neither mineralogical nor in vitro cytotoxicity assays unequivocally predict the contribution of quartz to their pathogenic potential.First, although Coal Workers' Pneumoconiosis (CWP) and Progressive Massive Fibrosis (PMF) prevalence have been found to correlate with total respirable coal mine dust exposure, and with coal rank (Attfield and Morring, 1992), epidemiological studies generally have not found the quartz component of coal mine dust as measured by X-ray diffraction or infrared spectroscopy (each of which essentially measures the mass-percent quartz in a bulk sample) to be clear predictors of CWP prevalence or incidence (Walton et al., 1971). Second, the properties which distinguish the extreme fibrogenic potential of quartz are not revealed by conventional in vitro bioassay comparison with other silicate mineral dusts. As an example, quartz and kaolin (aluminosilicate) clay in vitro cytotoxicities are comparable for lavaged primary pulmonary macrophages.The studies discussed here address these two anomalies from a general hypothesis that the pathogenic activity of respired quartz particles is associated with properties of, and interactions with, the particle surfaces. One factor in the expression of toxic activity by a particle surface is the biological availability of that surface. Anomalous lack of correlation of disease prevalence with mass percent quartz in exposures to some mixed composition respirable-sized dusts suggests that individual particle surface features, invisible by bulk sample mass analysis, may alter the biological availability of a fraction of quartz particles in a dust. For pure-surfaced mineral particles, the comparably strong prompt membranolytic activities of quartz and kaolin in vitro suggest that upon deposition of such particles in the lung there must be other interactions with particle surfaces which distinguish quartz. This might be due to toxic surface-associated sites specific to silica, or to interactions of other sites on other mineral particles which affect the biological availability of their toxic functional groups. For example, alurninol groups on clays affect the availability or activity of adjacent silanol groups. Surface activities which distinguish quartz pathogenici ty might be manifest in one or more of the sequential interactions upon deposition in the lung; first with the pulmonary surfactant system, then with extracellular and phagolysosomal enzymatic digestive processes, or with subsequent cytotoxic processes.

Dec 1, 1995

By W. H. Eddy

The Bureau of Mines conducted laboratory batch flotation tests and continuous pilot plant flotation tests on a complex calcareous fluorspar ore from Cave-in-Rock, Ill., to determine the technical feasibility of producing commercial-grade concentrates by the sodium fluoride-calcium lignin sulfonate-fatty acid method of concentrating fluorspar previously developed by the Bureau. The continuous flotation tests, treating about 150 pounds of ore per hour, produced fluorspar concentrates assaying 96.4 percent CaF2; 90 percent of the fluorspar was recovered.

Jan 1, 1967

By W. L. Crentz

The Black Mesa coal field is part of the Hopi and Navajo Indian Reservation in Apache, Navajo, and Coconino Counties, Ariz. The field is in an isolated area with the nearest railroad 70 to 90 miles to the south. Travel is restricted by roads that become impassable during inclement weather. The area is a mesa and rises from 500 to 2,000 feet above the surrounding territory. Water is very scarce, and the nearest stream of any consequence is the Colorado River about 90 miles northwest from the center of the field. Coal beds are found in the Mesaverde formation of the Cretaceous age, but they are uncorrelated and range from subbituminous to bituminous in rank. Huddle2/ estimates the reserves of subbituminous coal in Arizona at about 15 billion tons, most of which is in the Black Mesa field. The geology of the field has been reported by Campbell and Gregory.3/ Coal production is small, and the output is used almost exclusively for domestic fuel in the Indian schools, missions, and trading posts.

Jan 1, 1955

By I. L. Nichols, K. C. Dean, P. H. Johnson

Hydrochloric acid , sulfuric acid , and chloridizing roast- water leaching methods for dissolution of cesium and rubidium from Maine , Canada , and Southern Rhodesia pollucite ores and their flotation products were investigated by small- scale tests . Optimum conditions were determined to be ( 1 ) for hydrochloric acid leaching , use 12.7 equivalents of 8.8 normal acid per equivalent of cesium in the sample and leach for 6 hours at 100 ° C ; ( 2 ) for sulfuric acid leaching , use 12.7 equivalents of 14.4 normal acid and leach for 2 hours at 120° C ; and (3 ) for chloridizing roast - water leaching , roast minus 200 - mesh ore, limestone , and calcium chloride in a ratio of 2 : 4 : 1 , respectively , for 1 hour at 900 ° C , and leach the calcine for 1 hour at 80 ° C with enough water to give 35 pct solids . Extractions of cesium from ores and flotation products containing over 20 pct cesium were in excess of 97 , 93 , and 96 pct for the hydrochloric acid , sulfuric acid , and chloridizing roast - water leach processes , respectively .

Jan 1, 1964

Reduce the cost and incidence of low-back pain in underground coal mines through redesign of materials-handling tasks. Background Approximately 25 pct of all injuries in mining involve trauma to the hack. These injuries account for at least 30-40 pct of worker compensation payments made by the industry, are the leading cause of lost work days in mining, and have been estimated to cost the industry $50 million annually. It is clear that the traditional approach to reduce back injuries (i.e., training) has been largely ineffective. Thus, new approaches are necessary to control this problem. This document briefly describes methods that can be used to redesign hazardous materials-handling tasks to reduce the threat of worker injury. Approach A model for redesigning materials-handling tasks is shown in figure 1. The model outlines the sequence of steps that should be followed (and questions that should be asked) when developing new strategies for handling materials in underground coal mines. A critical examination of the current supply-handling system is the first step to developing safer materials-handling procedures. The purpose is to identify hazardous tasks that can be modified to reduce injury risk. Accident analysis (a review of past accident records) and task analy¬sis (usually a videotaped analysis of hazardous jobs or tasks) arc effective methods of distinguishing areas where job redesign is needed.

Jan 1, 1992

Use instantaneous sampling to pinpoint dust sources and to Improve dust control on longwalls. Approach Use a dust monitor developed under a Bureau contract. How It Works Sampling can be done by either a moving or a stationary method. In the "moving' method, the dust monitor is carried by a survey engineer walking at the midpoint of the shearer Dust levels and face position (support number) are taken during all phases of the mining cycle while the shearer is cutting. These measurements can show how changes in airflow along the face, face specific; (rock partings) and cutting sequence (cutting the wedge) variables affect dust levels. In the "stationary sampling" method, the survey engineer stands with the RAM at a fixed location on the face. As the shearer approaches, the dust level and the distance to the shearer are recorded at 10-second intervals. Typically measurements start when the shearer is 20 feet from the sampling position and continue as the shearer passes the position until it is 20 feet away on the other side. Dust profiles around the machine are obtained at several fixed locations along the face only while the shearer is cutting.

Jan 1, 1982

By G. W. Weems

The Bureau of Mines combined preconcentrating techniques and mass spectrometry to develop a parts-per-billion general analysis of impurities in helium. The impurities are preconcentrated using a Bureau trace-impurity analyzer; 35-mm Hg pressure of helium is left in the concentration trap to sweep the impurities into the mass spectrometry and provide a 10-mm Hg sample pressure.

Jan 1, 1966

By Robert W. Smith

Computation of the thermodynamic properties of the reaction products in the deflagration of explosive gas mixtures has been a most valuable guide regarding the possible kinetic mechanisms of homogeneous combustion processes. Knowledge of the physically possible end states is indispensable for understanding observed deviations from equilibrium in heterogeneous combustion. However such information on dust flames is entirely lacking. To complement a Federal Bureau of Mines study of stationary graphite dust flames burning in pure oxygen,6/ this report gives examples, at atmospheric pressure and room temperature, of composition profiles in an idealized oxygen-dust flame, with both mass and enthalpy being preserved. Similar profiles can be obtained from the data of the paper for elevated temperature and pressure.

Jan 1, 1960

By D. L. Sawyer

Aqueous C12-02 leaching procedures developed by the Bureau of Mines to produce zinc chloride from zinc sulfide bulk concentrates were effective in extracting 99 pct of the zinc and 97 pet of the silver contained in samples of massive seafloor sulfides from the southern Juan de Fuca Ridge. Zinc sulfide (sphalerite and wurtzite) mineralization comprised 55 and 88 pct of two specimens provided by the U.S. Geological Survey for this study. Minor occurrences of galena, chalcopyrite, and other minerals in the sulfides permitted the recovery of pregnant liquors that were low in metal values other than zinc, which were successfully purified by a two-step cementation procedure using zinc dust.

Jan 1, 1983

By Mark A. Ackerson, Kenneth E. Hjelmstad

An ideal fire warning alarm system for underground mines would be low cost, convenient, fast, reliable, and able to warn all underground workers. Present warning systems, such as phones, messengers, and stench, fail one or more of these criteria. The U.S. Bureau of Mines may have devised the ideal system. The one way communication system employs a large loop antenna and transmitter to create a 630 hertz (Hz) electromagnetic field to send information through-the-earth to cap lamp battery mounted micro- receivers worn by underground miners. Field tests of prototype equipment in 1986 resulted in through-the- rock signal transmission of over 762 m (2500 ft). Subsequent hardware upgrades for more recent tests resulted in transmissions of over one mile. Recently developed receiver circuitry employs phase- locked-loop detection circuitry responsive only to a specific series of pulses of given time duration, that eliminates false alarms from electromagnetic noise emitted by mine equipment, power lines, or lightning. A multichannel system can relay standard messages to miners

Develop personal computer (PC) based software for analyzing and/or filtering time- and frequency-domain attributes of seismic and electromagnetic signals from geophysical surveys for the enhanced interpretation of rock masses and subsurface geologic structure. The Problem Both mining and petroleum geophysicists utilize seismic signals to characterize rock masses for delineating subsurface stratigraphy and structural conditions. However, a vast amount of information available in seismic project evaluation data often is unavailable for interpretation unless these data are enhanced. New processing technology increases the quality of these signals for analysis and interpretation. Comprehensive signal processing software is mostly written for petroleum exploration companies. Commercially available signal processing programs are often limited to a single application or are restricted for use with specific hardware, e.g., a digital oscilloscope or a mainframe computer. The programs may use computer codes that are proprietary, restrict user modification to expand capabilities, or may be hard to interface. They may have insufficient documentation for easy use and be support dependent.

Jan 1, 1990

By R. L. Grant

The Bureau of Mines applied automatic computational methods to analyze the degree of correlation between sound transmission and atmospheric conditions. Statistical analysis of data collected over a 5-month period indicated that the following weather variables, listed in order of decreasing importance) have a significant effect on the transmission of sound in the atmosphere: 1. Wind velocity and wind direction. Winds in the direction of travel of the sound wave increase the sound intensity and duration. 2. Barometric pressure. High pressures are related to low sound intensities and durations. 3. Atmospheric temperature. High temperatures are related to low sound intensities and durations. Inversion of the atmospheric temperature did not appear to affect sound transmission under the conditions of this study.

Jan 1, 1967

By Parviz F. Rad

The Bureau of Mines conducted groove cutting experiments in marble, lime-stone, granite, and quartzite with a 7-inch disk cutter under a normal thrust of 7,000 lb. The values of muck weight per unit length, specific energy, cutting coefficient, and groove depth for each of these rocks were determined for groove spacings ranging from 0.1 to 4 inches, and from these results the values of optimum and critical spacing were computed" The results indicate that compressive strength may be used to predict some of the cutting characteristics of the independent grooves. Considering all the cutting characteristics, particularly those for the interacting grooves, Shore hardness, coefficient of rock strength, and torsional velocity correlate with cutting characteristics better than do other physical properties. Some of the field applications of the principles established in this report are identified.

Jan 1, 1974

By Terry J. Close

In 1992, as part of the U.S. Bureau of Mines Idaho Land Assessment Program, the Western Field Operations Center investigated the mineral resources of the 30,300-hectare Elk Summit study area. The area is in the Clearwater National Forest, adjoining the Selway-Bitterroot Wilderness in Idaho County. Idaho. The study area is underlain by granitic and metasedimentary rocks. Associated with these rocks are road metal (stone) resources, black sand mineral placer resources, and thermal water resources. Also present are abundant sand and gravel. Two of the five sites examined during the Bureau study have road metal (stone) resources, one has black sand mineral resources, one has thermal water resources. The fifth site is a black sand mineral placer occurrence. There is no evidence of petroleum or coal resources. Idaho County records indicate that 38 mining claims, mostly black-sand placer, have been located in the study area, Twenty-three of the claims are current. Workings consist of a few pits and trenches at the placer, and two borrow pits. The only mineral commodity produced from the area was about 1,500 tonnes of stone excavated from the Savage Pass and Swamp Creek borrow pits along the Elk Summit road, north of Hoodoo Lake. The stone was used to surface the road; these stone resources will continue to be used as needed.

Jan 1, 1993