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By H. C. Loesche

The problem of signaling to the hoisting engineer from the cage in a shaft mine has been given considerable thought and attention by engineers and mine operators seeking to Increase the safety and efficiency of hoisting. HISTORY R. L. Rutherford,3/ an employee of the Magma Copper Co., Superior Ariz., realizing the need for a simple and practical moving-cage signaling system, began a serious of experiments early in 1937, Available electrical moving-cage signal in operation at this date required that signal wires be installed in the shaft to make a simple, positive signal without wires, the first experiments used the pipe lines in the shaft for carrying the signal current, but these experiments were not successful.

Jan 1, 1945

By Wesley A. Grosh

The Allah Cooper mine, in Louisa County, Va., formerly was a producer of lead and zinc. It was believed that the critical shortage of leach and zinc and the fact that some ore had been produced at this mine justified exploration of it. A preliminary examination was made on April 30, 1943, by J. E. Hill, a Bureau of Mines Engineer. Diamond drilling was done on the property from November 30 to December 18, 1943, to determine whether the sulfide body extended to depth. One hole drilled to a depth of 650 feet and located so as to cut the Allah Cooper ore shoot about 150 feet below the lowest known mine workings failed to disclose sulfide vein at that depth.

Jan 1, 1949

By Robert W. Freedman

This report describes sampling and analytical procedures used for measurement of sulfates in diesel tailpipes and in the diluted exhaust within dilution tunnels. A variety of methods exist for sulfate analysis for such systems, including ion exchange. Two chemical methods used by the Bureau of Mines are described in detail. These are based upon spectrophotometric measurement of chloranilic acid using barium chloranilate. The procedures are rapid and relatively inexpensive. In general, ion exchange is preferred by many analysts for sulfate analysis. However, it is more complex and expensive than chloranilic acid procedures, which are adequate for exhaust analysis.

Jan 1, 1982

By A. L. Engel

The sample of ore on which the work described in this paper was done came from Mina Oriente, Carrizal Bajo, Provincia de Atacama, Chile, South America, and was sent at the request of the Chil.ean Government through the Foreign Minerals Division of the Bureau of Mines. This ore had been tested locally for treatment by flotation and cyanidation without satisfactory results. An additional difficulty was the absence of water near the ore deposits, so that in any treatment method considered the water requirements would have to be very low. It was desired to develop a practical method of recovering the gold and, if possible, the copper in the area. No data of previous investigations were made available. The sample received was mostly quartz, highly brecciated, with limonite and hematite in the fractures. Copper occurred as malachite and azurite, also in the fracture s and to a slight extent as a stain in the quartz. Some fine-grained pyrite with a little arsenopyrite occurred within the quartz. An occasional grain of chalcopyrite was observed. No free gold was seen during examinations of the ore, but amalgamation indicated that some was present.

Jan 1, 1949

Provide an accurate, reliable means for determining when a sealed mine or mine section can be safely reopened after a fire. Approach The Bureau of Mines performed a research investigation that resulted in the development of a mathematical formula for deriving a quantity, called RATIO, which can be used to define when a sealed mine or mine section has returned to safe recovery conditions after a fire. Research Results There were two major results from this Bureau research. Over a period of several years, the Bureau of Mines conducted six experiments at its Bruceton Experimental Mine in Pennsylvania. The experiments involved sealing the mine after several tons of piled coal had been allowed to burn continuously for 2 to 3 days. Although gas data obtained during the experiments revealed nothing significant, measured smoke particle levels were found to correlate with the stages of combustion and temperatures of the smoldering coal pile. Moreover, it was found that no smoke particles are produced when high-temperature smoldering exists deep within the mass of the coal pile since the smoke particles are filtered by the coal surrounding the hot region. Smoke is emitted into the mine atmosphere only if combustion is occurring near exposed surfaces. As suggested by these findings, any decision to recover a sealed mine area based primarily upon the absence of smoke particles is not a wise derision.

Jan 1, 1988

By A. L. Murray

"Welfare endeavor in connection with both the metal and the coal mines of Utah has shown gratifying progress during recent years, and in most mining towns of the state, both the operators and their employees deserve much credit for the efforts put forth to better the living, working, educational and recreational conditions. Progress has been and is being made, but there are still a few important towns where purer water and better sewage disposal are pressing needs.In the older metal-mining towns that are incorporated and are independent of the mining properties operating in the vicinity, less opportunity is presented for the companies to exercise efforts looking toward improved welfare conditions than in company towns controlled by the mine operators.However, even in such towns the companies can do much to better welfare conditions, as shown by the progress in Bingham Canyon during the past several years. The Utah Copper Company has spent $800,000 since 1920, in the erection of modern brick cottages, apartment houses and the Germnell Memorial Club. The cottages and apartment houses have every convenience to be found in up-to-date city homes. The Gemmell Memorial Club erected and equipped at a cost of $175,000 was provided by the company for the benefit of the Utah Copper employees living in the canyon and has been made the recreational center for the camp. Another improvement is the $100,000 fireproof hotel built by the United States Mine of the United States Mining, Smelting and Refining; Co. in the Copperfield section of Bingham Canyon. This hotel will accommodate 105 men exclusive of hotel help and has all the conveniences of a city hotel."

Sep 1, 1925

By John R. M. Hill

The Bureau of Mines performed elastic-plastic, finite-element analyses to investigate the support performance of hydraulic backfill. A mathematical model was developed for two vertically adjacent stopes separated by a sill pillar. An exact duplicate of a working stope was not intended; however, the model did simulate a working stope to the extent that field measurements from an active stope could be used for comparative purposes. Using a predetermined mining sequence, the computer analysis simulated the mining operation as a series of incremental cut-and-fill steps. Computer results included a complete history of stope closure and pillar stresses throughout the mining sequence. With the mining sequence and rock properties held constant, three separate analyses were made using varying backfill properties. These cases included no fill,-low-to-medium-quality fill, and medium-to-high-quality fill. Results of these analyses show decreases in stope closure and pillar stresses as the backfill quality increases, thus reducing the possible occurrence of rock bursts. Predicted stresses within the backfill compare favorably with field measurements. A relationship between maximum stress normal to the stope wall and the ratio of relative fill stiffness to relative rock stiffness was also indicated.

Jan 1, 1974

By G. V. Sullivan

This report describes an investigation by the Bureau of Mines of flotation techniques for the recovery of chromite from fine-grained disseminated ores. Reported work on the concentration of chromiferous materials shows that flotation has been applied almost exclusively to slime-free pulps. Therefore, chromium recoveries that could be obtained by flotation were related to the amount of slime rejected. However, results of recent studies by the Bureau of Mines showed that des liming is not a requisite to selective concentration of chromite. Laboratory-scale tests on seven ore types from the more important chromium-bearing areas of the Pacific Northwest showed flotation to be technically feasible for treatment of all but one of the samples. Concentrate grades were affected more by the composition of the chromite mineral than by the grade or character of the ore. Test results from three of the samples showed that, without prior desliming of the pulp, 78 to 91 percent of the chromium could be recovered in concentrates of 90 percent or more chromite; two samples responded to similar treatment, resulting in concentrates of more than 80 percent chromite with recoveries of 85 and 89 percent chromium. One sample of mill products, subjected to severe weathering, required removal of the primary slime to obtain a concentrate of 65 percent chromite with only 75 percent chromium recovery.

Jan 1, 1960

By Roy H. Grau, John C. LaScola

This Bureau of Mines report contains a tabulation of methane emissions during 1980 for all coal mines located in the United States with emissions greater than 0.1 MMcfd. Listed for each mine are methane emission quantity, location, and coalbed. The report also compares records of 1975 and 1980 and describes relationships between emissions in 1980 and the Bureau's coalbed gas content data on 11 mines.

Jan 1, 1984

By Benjamin W. Haynes

Materials from phosphate rock mining and processing were analyzed for fluorine and uranium content as part of the Bureau of Mines program to more effectively recover resources from mining and mineral processing reject materials. The analysis of both feed and waste materials generated in the beneficiation and acidulation of phosphate rock was performed to obtain information on the disposition and concentration of these elements in phosphate rock processing streams. Fluorine was determined by a distillation-titration method and by ion chromatography. Uranium was determined by the dibenzoylmethane (DBM) method, the reliability being confirmed by roundrobin analysis of samples within Bureau of Mines research centers. National Bureau of Standards (NBS) Standard Reference Material (SRM) 120b-Phosphate Rock was also analyzed for fluorine and uranium to verify procedures and results. Fluorine values ranged from 0.3 wt-pct in gypsum filter cake to 3.7 wt-pct in phosphate rock concentrate. Uranium ranged from less than 5 µg/g in gypsum filter cake to 200 µg/g in a dried clay slime.

Jan 1, 1981

Avoid accidents that can occur when applying belt dressing from an aerosol can, particularly when can pressure has dropped or when spraying against wind. Approach Use a garde-type sprayer. How It Works Commercially available garden-type sprayers can be used for applying conveyor belt dressing from 12 feet away, or more. Pressure is easily raised and maintained at about 50 psi. Most sprayers have a hand pump, but a battery-powered cordless model is also available. Garden-type sprayers are available in various sizes from 11/2 to 18 gallons, with the larger models wheel mounted. The 3-gallon model evaluated by the Bureau has a shoulder carrying strap, which gives additional safety advantages. Use of the strap frees both hands for climbing ladders or holding onto catwalk rails. When spraying, one hand can remain on a handhold to lessen the chances of touching a moving belt.

Jan 1, 1980

By J. P. Conway

The yielding-rock-bolt concept, as developed in South Africa, consists of a smooth-bore die or collar fitted to a standard rock bolt. Laboratory testing at the Bureau of Mines Spokane Mining Research Center under slow and fast strain rates showed that extrusion loads can be controlled by varying the configuration of the die bore and that theoretical analysis (using basically Sachs' theory of wire drawing) predicts extrusion loads of the different die-bore configurations. A derived equation, based on this research, can be used for designed die-thread combinations for any desired extrusion load. Dynamic loading resulted in slightly higher loads (15 percent) than static loading. The strain hardening effect, which increases yield and ultimate strength, was partly offset by adiabatic heating of the threads, which decreases strength.

Jan 1, 1975

By E. J. Kloos

Bureau of Mines-approved self-contained breathing apparatus of the compressed air demand type were evaluated for performance at low temperature. Apparatus durations, breathing resistances, and airflow rates were measured on machine tests at room temperature and -25° F. Man tests under actual wearing conditions verified the machine test results. Many serious functional changes in apparatus performance occurred at low temperature. Pressure regulators malfunctioned when diaphragms lost flexibility. Under certain conditions frozen condensed moisture sealed exhalation valves and fogged eyepieces. High-pressure leaks, not encountered at ordinary temperature, developed at low temperature. Tests results are discussed generally and specifically for each apparatus. Recommendations are given to obtain optimum performance from demand type breathing apparatus at low temperatures.

Jan 1, 1968

By Rudolf E. Greuer, Linneas W. Laage, Xinton Chang

INPUT FORMAT INSTRUCTION FILE FOR PROGRAM MFIRE GENERAL RULES FOR DATA INPUT: $THERE IS NO NEED TO DISTINGUISH INTERGER AND REAL NUMBERS. $ $ SYMBOLS FOR NUMERICAL INPUT INCLUDE THE FOLLOWING $ $ 1234567890 -+BLANK $ $ * FREE FORMAT IS ALLOWED. COMMA AND BLANK SPACE CAN BOTH BE $ $ DELIMITERS. SEQUENTIALLY DISTRIBUTED BLANK SPACES ACT AS ONE $ $ DELIMITER. BLANKS ADJACENT TO A COMMA HAVE NO DELIMITING EFFECT $ $ * A ZERO INPUT CAN BE OMITTED BUT NOT THE DELIMITERS EXCEPT WHEN $ $ THE ZERO INPUTS ARE THE LAST ONES ON A LINE. $ $ * A LINE WHOSE FIRST NON-BLANK SYMBOL IS "$ IS AN INSTRUCTION $ $ LINE WHICH WILL BE IGNORED IN A PROGRAM RUN. $ $ * A LINE WHOSE FIRST NON-BLANK SYMBOL IS NEITHER ONE USED IN THE $ $ ABOVE LIST FOR NUMERICAL INPUT NOR "$, OR WHICH CONTAINS MORE $ $ THAN 3 SYMBOLS OUTSIDE OF THE LIST, IS A COMMENT LINE WHICH WILL $ $ BE SHOWN IN THE OUTPUT FILE. $

Jan 1, 1990

By Robert P. Vinson, Fred N. Kissell, Edward D. Thimons

Because of the high number of accidental methane gas ignitions in metal and nonmetal mines, the Bureau of Mines searched for a simple guideline that would allow mine personnel to evaluate the methane hazard in a given mine. Air samples were collected by the Bureau in 53 metal and nonmetal mines and analyzed for trace evidence of methane gas. Samples were collected in the returns and at the working faces. Those mines classified as gassy by the Mine Safety and Health Administration had a significantly higher average methane concentration than those classified as nongassy. Of the 9 gassy mines sampled, 7 had methane concentrations above 100 ppm, whereas only 1 of the 44 nongassy mines had a concentration above 100 ppm. The 100-ppm concentration may be used as a simple and convenient guideline for forecasting the methane hazard in a mine, whether or not the mine is classified as gassy. There was no consistent correlation between commodity mined and methane concentration, nor was there a correlation between mine depth and methane concentration. Neither of these factors can be considered a guideline for predicting methane hazards.

Jan 1, 1979

By John R. Benham

The Long Swamp RARE II area contains no prospects, claims, or mines. It has a low potential for ore deposits. There are no geothermal, oil, or gas leases in the area. APPRAISAL There are no mining districts in the study area. The nearest is Chewack Mining District, which is 6 mi (9.6 km) north of the area. This district had numerous claims located for tungsten; the principal tungsten ore mineral was wolframite. Wolframite was found here in 1898 by surveyors of the International Boundary Commission. The area was staked in 1908 and developed during 1915 and 1916. Only in 1936 was ore shipped; the 30 ton (27.2 t) shipment proved to be unprofitable for the claimants (Culver, 1945, p. 41).

Jan 1, 1982

To recover metals as sulfide concentrates from contaminated waste streams using hydrogen sulfide (H2S) generated by the bacterial digestion of waste organic materials. Approach The goal of this research is to develop a treatment method for metal mine effluents that will rival the cost and convenience of conventional lime treatment, and that will provide better effluent water quality, result in less expensive sludge disposal, and allow for the selective recovery of metals.

Jan 1, 1993

Determine whether the total delay time in blasting may be safely increased beyond the currently permitted 0.5 s, without igniting a methane or methane-coal dust atmosphere and determine the minimum borehole spacing to avoid misfires. Approach At present, regulations limit the delay time used in short-delay blasting to a total of 0.5 s. Many in industry and government would like to see this total delay time increased to 1 5 to permit an increase in the number of different delays available for short delay blasting and an increase in the time between delay periods. The Bureau of Mines conducted research to determine whether the total elapsed delay time for blasting coal in underground mines could be safely expanded, with resulting improvements in productivity. The research was conducted at a surface mine in St. Clairsville, Ohio. Experimental shots were conducted in several pits, each of which had a 5-foot-high coal seam (Pitts-burg No.8) in a 50-foot highwall. The coal seam and a mobile gallery provided a good simulation of an underground coal face. The Bureau also examined the relationship between borehole spacing and misfires, to check on reports over the past few years that permissible explosives frequently misfire. These reports were not well documented, but were numerous enough to warrant investigation. Misfires of permissible explosives in an underground coal mine can be very hazardous; a burning cartridge of explosive may be ejected from a borehole and ignite the gas or dust in the mine, or a misfired cartridge in the muck pile may detonate during drilling and mucking operations, causing serious injuries.

Jan 1, 1986

By Wilbur I. Duvall

This report presents experimental data on the propagation of explosion- generated strain pulses in rock. Tests were performed in 5 different rock types, employing 10 different types of explosives. Charge sizes ranged from 0.5 to 50 pounds, and travel distances ranged from 2.5 to 70 feet. Analysis of the data shows that the experimental peak strain data satisfy an exponential decay propagation law of the form: ?R/W1/3 = Ke ?aR/W1/3. For a particular rock, parameter K is a linear function of the calculated detonation pressure or the calculated energy density of the explosive. For a particular explosive, K is a linear function of the elastic parameter of the rock, p2, a result, which is at variance with elastic theory. The absorption constant, a, is independent of type of explosive but dependent upon rock type. However, no definite relation between a and the physical properties of the rock could be established.

Jan 1, 1959

By G. W. Jones, R. E. Kennedy

Most gasolines and naphthas are mixtures of paraffin- series hydrocarbons and comprise such substances as pentane , hexane , heptane , octane , and others up to perhaps dodecane . Many of these hydrocarbons , when mixed with the proper proportions of air and ignited , are highly explosive . It is due to this characteristic that gasoline has become so important as a fuel in internal -combustion engines . Gasoline and naphtha also are used in the industry as solvents and cleaning agents . Because of their explosive properties they are dangerous to use unless the composition is so chosen that the vapor pressure of the mixture is not high enough to produce explosive mixtures with air at the temperature at which they are used . Hydrocarbon mixtures may be made less hazardous by adding some incombustible liquid , such as carbon tetrachloride . Barrier reports the amount of carbon tetrachloride that must be added to different naphthas to render such mixtures free from fire and explosion hazards . He found that the amount of carbon tetrachloride that must be present in the final mixture of naphtha and carbon tetrachloride varied with the density of the naphtha . Of the naphthas tested the amount of carbon tetrachloride necessary to render such mixtures free from fire and explosion hazards ranged from 30 to 70 percent . .. Determination of the fire and explosion hazards of carbon tetrachloridehydrocarbon mixtures would be easy if the boiling points and vapor pressures of the two were the same at any given temperature . The fact that carbon tetrachloride boils at 76° C. while the boiling points of the hydrocarbons found in gasoline and naphtha may range from 37° , the boiling point of pentane ,

Nov 1, 1934