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By Julie Mitchell, Robert King, Len Eros

The Bureau of Mines has studied the Deserado Mine computerized monitoring and control system, located in Rangely, Colorado, to acquire knowledge about the overall costs and benefits of mine monitoring systems. The Deserado system is a complex system monitoring environmental parameters, electrical power, and operation of all mine equipment, and controlling the entire conveyor haul age system. This paper discusses the evaluation of the Deserado monitoring system from initial design through system installation and operation. It also examines the costs, benefits, and performance of the monitoring system.

By William L. Rice

Geochemical humus sampling techniques were used by the Bureau of Mines in investigating a potential large, low-grade gold deposit in the Orogrande district, Idaho. Conifer needle humus samples were processed by ashing and fire assay-atomic absorption analysis. An area bearing anomalous concentra¬tions of gold and silver was outlined by the geochemical method.

Jan 1, 1970

By John Nagy, Henry G. Dorsett, Murray Jacobson

Laboratory studies show that ignition of a dispersed combustible dust in an open vessel may be prevented by adequate inerting . Factors affecting the inerting requirements are -- dust concentration , spark energy , ignition temperature , composition of the substances used for inerting , fineness of dust and type of combustible . The oxygen concentration of the atmosphere and in some instances the proportion of admixed inert powder and moisture required to prevent ignition are given for 367 dust samples . Variations in inerting requirements with strength of igniting source are discussed .

Jan 1, 1964

By W. Blake, J. Whyatt

Sixty years of rockbursting in the Coeur d’Alene district has taught painful lessons and led to a number of practical advances in controlling rockburst hazards. This paper summarizes those lessons, concentrating on practical measures that have been successfully adopted to reduce hazards. These lessons are explained in the context of district mining history and current understanding of rockburst phenomena. Overall, the paper provides the practicing mine engineer with an appreciation of rockburst hazards and an overview of practical measures that can be used to control these hazards in the context of Coeur d’Alene district experience.

By Fred N. Kissell, Jon C. Volkwein

In This Chapter [How inert gas works to prevent methane explosions How inert gas is generated and delivered at highwall mines Volume and quality requirements for inert gas at highwall mines How an inert gas system is operated and Precautions to take during mining to prevent methane explosions] This chapter discusses a method, originally developed by Volkwein and Ulery [1993], to prevent methane explosions during highwall mining. In highwall mining, a horizontal auger or a mining machine enters the coal seam from a surface mine pit at the bottom of a highwall, and the coal is mined out from a series of parallel holes. Explosions can be prevented by injecting inert gas into each hole as it is mined. Coal near the surface has lost most of its methane gas over time. However, in recent years, surface mining has been used for deeper reserves of coal. This trend toward mining deeper reserves has increased the chance of encountering methane, and methane explosions at highwall mining operations have resulted in injuries. HOW INERT GAS WORKS TO PREVENT METHANE EXPLOSIONS A methane explosion requires the presence of sufficient amounts of both methane and oxygen, as well as an ignition source. If the methane cannot be reduced and the ignition source cannot be eliminated, then explosions may be prevented by adding an inert gas, which contains little to no oxygen, to the mixture [FWQA 1970]. Just how much inert gas must be added depends on the mining rate, as well as the composition of the inert gas. An explosibility diagram can be used to show whether a methane mixture is explosive after inert gas is added [Zabetakis et al. 1959] (Figure 10–1). This diagram indicates that gas mixtures fall into one of three range categories—explosive, explosive when mixed with air, and nonexplosive—depending on the percentage of methane and percentage of “effective inert.” Effective inert is calculated from the percentage of “excess nitrogen”3 and percentage of carbon dioxide in the mixture.

Jan 6, 2006

By Thomas C. Ruhe

The Bureau of Mines conducted research to determine the safe operating conditions for using recycled (used) lubricating oil from mining equipment as a partial replacement for diesel fuel to make ANFO-type blasting agents. The use of recycled oil (RO) saves energy, reduces oil imports, and reduces mining costs. Low ambient temperatures may cause these recycled oils to become too viscous for proper absorption by ammonium nitrate (AN) prills and result in poor blast performance, safety hazards, and environmental problems. To help quantify and resolve these issues, viscosity, mixing, and performance tests were conducted at various temperatures. Diesel fuels No. 1 and No. 2 were studied separately and in blends with 25,50, and 75% RO. Good quality ANFO mixes (94-6) were produced with dry absorbent prills and blended fuel (No. 1 diesel plus RO) at temperatures as low as -40° F (-40°C) with 75% No. 1125% RO, and at -20°F (-29°C) with 50/50. Diesel fuel No. 2 also made good mixes as low as -30" F (-34" C) with 75% No. 2/25% RO, and at 0° F(-18° C)with 50/50. Reference detonation velocity tests were conducted in 1.4" (3.6 cm) diameter steel pipe at 70°F (21°C) on No. 1 diesel ANFO (94-6), giving an average value of 9722 ft/s (2964 m/s). Comparison tests showed good ANFO performance at low temperatures. Blended fuel ANFO (75% No. 1/25% RO) mixed, loaded, and tested at -40°F (-40°C), produced an average velocity of 9247 Ws (281 8 m/s). A 50/50 blend gave a velocity of 8083 Ws (2464 ds) at -20°F (-29°C). Based on these results, a practical field method has been developed to help evaluate whether a specific oil blend will mix properly with AN at a low ambient temperature. This method will help to promote the safe and reliable use of RO ANFO at low temperatures, with adequate performance.

Jan 1, 2008

By George D. Dub, FREDERICK G. MOSES

The Bureau of Mines, in connection with the investigations of war minerals it conducted, examined the graphite deposits of this country, studied the methods of mining and preparation used, and sought to devise more efficient methods for the preparation of do- mestic graphite, and to standardize the quality of the product. The graphite investigations covered three general phases, as follows: 1. An examination of the deposits in Alabama and other States, and a survey of the methods of mining and preparation used. In this connection methods of sampling and analysis were noted and ex- periments made to determine a standard method of sampling and a rapid but accurate method of analysis. 2. Experimental work on the concentration and refining of domes- tic crucible graphite to improve the quality of the product and to lessen waste. 3. Experimental work in crucible manufacture to determine the properties of domestic flake and the maximum proportions that might be used without impairing the quality of the crucibles. This work was accompanied by photomicrographic study of crucible structure. In this bulletin are presented the results obtained in the first two phases of the work outlined above. The bulletin is in two parts. The first part describes the methods of mining and milling used, suggests a standard method of sampling finished graphite, and de- scribes a rapid and convenient method of analysis developed at the Pittsburgh station of the Bureau of Mines, to which had been as- signed the analytical and microscopic work. The second part describes experiments on the concentration and milling of graphite, which were made at the Salt Lake City, Utah, station. As soon as the reports incorporated in this bulletin were ready, mimeograph copies were distributed to those persons most interested in order to make the results immediately available. The experimental work on crucible manufacture, assigned to the Columbus, Ohio, station, yielded results which were made known to the industry. Á report on this work will be published later as a separate bulletin.

Jan 1, 1920

By M. C. Simmons, Boyd Gutorie

Desulfurization experiments at the Petroleum Experiment Station of the Bureau of Mines at Bartlesville on virgin light distillates obtained from some ‘high-sulfur’ crude oils have shown that the octane numbers of the original distillates are increased on the average about one unit, that the octane numbers of distillates with 4 ml. tetraethyl lead are increased 2 to 3 units, and that the The Petroleum Experiment Station, at the request of the Petroleum Administration for War, instigated and has in progress an investigation of crude oils of the United States to determine their possibilities for yielding straight-run distillates suitable for use as base or blending stocks to produce high octane aviation gasoline. One phase of this investigation deals primarily with so-called ‘high-sulfur’ or ‘sour’ crude oils by seeking to determine the effects of sulfur removal upon the virgin distillates prepared from these crude oils. To date, virgin distillates from several ‘high-sulfur’ crude oils from Texas, New Mexico, and Oklahoma have been prepared and desulfurized in pilot-plant distillation and desulfurization units at the Petroleum Experiment Station. The properties of the undesulfurized and desulfurized distillates were determined and compared to show the effect of sulfur removal. Results of these investigations showing the suitability of these crude oils as sources of virgin naphtha aviation base stocks have been prepared and forwarded to the Petroleum Administration for War and other approved persons. The following preliminary summary is presented to acquaint those interested not only with the present results of the investigation of several ‘high-sulfur’ Texas, New Mexico, and Oklahoma crude oils, but also to give some basic information as to certain sulfur compounds, especially their identification in straight-run distillates, their depressing effects upon the octane numbers of leaded fuels, the benefits obtained by their partial and complete removal, and some of the processes being used to effect their removal.

Nov 1, 1943

By Joseph T. Singewald

The term "titaniferous magnetite" is used to designate those mag- netic ores of iron that carry more than 2 or 3 per cent of titanium. Large and easily workable deposits of these ores occur in different parts of the world, and have attracted attention for many years. Under present furnace practice, however, the smelting of these ores is both difficult and expensive, and for that reason they are not accepted by furnaces, so that the deposits are practically worthless. The problem of finding a feasible method of utilizing these ores has naturally been attractive, and numerous attempts have been made to solve it. Experiments to that end embrace two lines of investigation. The one that has been the more frequently tried is the elimination of the titanium from the ores, so as to make possible their smelting in the usual way. The other is the devising of a method of smelting by which titaniferous ores may be reduced as economically as are non- titaniferous ores. The former method involves a physical process, the latter a chemical process. The measure of success attainable by the first method depends entirely on the relations between the iron and the titanium in the ore. Views in regard to these relations have been divergent. Some investi- gators have believed the titanium to occur as a part of the magnetite molecule, in which case, of course, any process of mechanical separa- tion would be impossible. Others have believed that the titanium occurs as the mineral ilmenite, and that the ores are aggregates of magnetite and ilmenite. In this case a separation of the two minerals is theoretically possible. Magnetite is highly magnetic; ilmenite is nonmagnetic or only feebly magnetic. Crushing and magnetic con- centration should separate them. Numerous experiments in mag- netic separation have been made with various degrees of success, but rarely has more than a very imperfect separation been obtainable. In other words, some of the titanium exists in a separable form and some in an inseparable form, and the ratio between the two forms is

Jan 1, 1913

By S. J. Page, J. A. Organiscak

Airborne respirable dust surveys were conducted at six surface coal mines to investigate the effectiveness of dust control methods used on rotary rock drills and bulldozers. Dust controls commonly used on drills include a dry dust collection system, exhausting from a shrouded area around the collared hole, and an enclosed drill operator cab, filtering airborne dust from the cab. Bulldozers are also typically equipped with an enclosed operator cab as a dust control measure. Airborne respirable dust sampling was conducted near each equipment's source of generation and inside its enclosed cab. Silica analysis was performed on the dust samples to determine the percent silica content in the dust generated at the six mining operations. An additional eight- month follow-up of dust sampling was also conducted in the enclosed operator cabs of several rock drills and bulldozers. Data were analyzed for long-term variability of accepted control methods to abate dust and silica levels. The highwall rock drill was the major and most variable dust source as compared to the bulldozer, generating dust levels, on average, one order of magnitude higher than dust levels of the bulldozer. Four of the six drills surveyed had dust containment and capture problems at the shrouded drill table above the lple. Repairs or modifications to three of the drill dust collection systems were shown to reduce dust levels by more that 50% next to the shrouded drill table. The enclosed operator cabs provided more than 90% and more than 40% lower dust levels than at the dust source for the drill and bulldozer, respectively. Long-term sampling of several of these highwall drills and bulldozers showed that the dust levels in the drill cabs were frequently higher than 0.2 mg/m3 and more variable than in the bulldozers. The bulldozer dust levels were frequently below 0.2 mg/m). Future research should focus on improving some of the deficiencies present in the drill's primary dust collection system, and developing quality control methods to ensure the integrity of enclosed cab protection for equipment operators.

By James A. Powell

A seismic system which utilizes in-mine geophones to detect trapped miners has been developed. Tests at the Bureau of Mines Safety Research Mine at Bruceton, Pa., and at two operating mines indicate such a system has a maximum detection range in excess of 1,000 feet. The system is fieldworthy and portable and requires less than 30 minutes to set up and check. Real-time detection is possible.

Jan 1, 1976

By S. P. Howell

The Bureau of lines as repeatedly called attention to dangerous practices in the transportation and opening of kogs of black blasting powder. In 1914 Diwin Higgins (Prevention of Accidents from Explosives in Metal inos, Miners' Circular 19, Bureau of Mines, p. 15) stated "canisters should always be opened by removing the bung. To use a pick or other sharp tool for cutting a hole in the canister is dangerous. After the necessary amount of powder has boon taken out, the canister should be kept closed. The powdor should always be handled at a safe distance from an open light." In 1919, Geo. S. Rice (onthly Statement of Coal line Fatalities for June, 1919, Bureau of Mines, pp. 16 to 18) calls attention to the dangers that arise in underground transportation and handling of explosives, and calls special attmtion to the danger of hauling explosives in motor trips; the unnecessary risk involved in hauling men on the trip at the same time, and the necessity of keeping open lights away from black blasting powder. In 1919 the writer (Sensitiveness of Explosives to Frictional Impact, Tech. Paper 234, Bureau of Mines, pp. 13, 15) called attention to the fact that black blasting powder is not as sensitive to frictional impact as the nitro-glycerin dynamites and the gelatin dynamites. Black powder may be ignited by direct impact and the writer believes that this may occur without presupposing a preliminary spark. It is well known, however, that black blasting powder is very sensitive to ignition by spark flame, or heated materials, and these may be produced by an electric current, by an open light, by incandescent particles from a pipe, cigar, or cigarette, by the tearing of metal sheets or scraping of metal against metal, and possibly, by other means. -- The above discussion will serve to introduce a newly recognized hazard the ignition of black blasting powder by the forcible opening of kegs with wodden tools. The details of three accidents in which kegs of black blasting powder ex- ploded instantly when a wooden tool was driven forcibly through the top of the kegs are as follows: 1. In 1915, a powder man employed by a coal mining company stated that he was opening a 25-pound log of black blasting powder by driving a hole in the top with a wooden sprag when the powder in the leg ho was opening ignitod. This caused the ignition of fifty-two additional 25-pound logs of the powder, and the fatal burning of this and another powder man. The ono making this statement lived five hours after the explosion.

Sep 1, 1920

By J. H. East

Potash is one of the essential chemicals used in fertilizing soil deficient in natural minerals . Europe uses a large tonnage of potash in the form of easily soluble salts , and this is particularly true of those countries where the natural minerals in the soil have been exhausted owing to intensive cropping of the land . The application of potash to the soil in these countries is essential if normal crops are to be obtained ; during the war , some European countries were unable to obtain sufficient potash , and productivity of the farming areas declined seriously . • The largest -known deposits of potash in the world ; with the possible. exception of Russia , occur in Germany , and the German output of processed salts constituted about 65 percent of world production prior to the war . The German potash-plant installations are large , modern , brick and steel construction and apparently built for a planned operation of many years . Two districts produced approximately 80 percent of the German potash; the Werra -Fulda district , near Vacha , had the largest production , and the Sudharz district , near Nordhausen and Sonderhausen , was second . (Fig . 1. ) Hannover and Stassfurt were two smaller producers . Potash fertilizers are rated in terms of potassium oxide (K20 ) . The usual basis for calculation of production or application of the salt is to reduce the potash content to 40 percent K₂0 .

May 1, 1947

By D. B. Dow

The transportation of any commodity which is actually or potentially a source of fire or explosion, has been made safe, insofar as humanly possible, by rigid requirements as to inspection mechanical safety devices, and by printed labels. For the most part these precautions have been sufficient. This is evident when it is considered that in the thousands of instances in which commodities with a great fire risk have been transported, few disasters have occurred. This paper deals with the recent gasoline explosion which occurred at Memphis, Tennessee. At 7:50 a.m. January 24, 1921, vapors from a tan: car of gasoline became ignited and resulted in a blast that killed eleven people and badly injured nineteen others. Probably forty or fifty men, women, and children received slight injuries from falling debris or from burns. The explosion wrecked an oil plant, leveled a block of frame buildings, and broke window panes within a radius of five blocks.

Feb 1, 1921

By F. B. Tough

An inusual job in controlling a gas well was executed on No. 1 well, Inland Oil and Refining Co., situated on the Alkali Butte structure, Freemont County, Wyoming. The work was done by the company in cooperation with the . S. Bureau of Minos, and resulted in a fuel saving of $5,000 in one season and of a repair job estimated at $15,000, or a total of $21,000. The woll had an open flow of 6,000,000 cubic feet of gas per day with a rock pressure of 560 pounds per square inch. A string of 6-1/4 inch casing with a toothed shoe was set on the cap rock above the gas sand at 2181 feet. Then the well was shut in, the gas worked out around both the 6-1/4 inch and 6-1/4 inch strings, breaking through the ground surface at several points under the derrick. Casing troubles encountered while drilling made it unsafe to attempt Coving the 6-1/4 inch string. Moreover, it was important from the standpoint of good management to make the gas from this well immediately available for fuel in other operations and, in addition, to save the gas from wasting. An ordinary mudding and cementing job would have necessitated sitting down this well for probably two months out of a very short operating season. For these rousons it was determined to mud the well, if possible, between the 6 and 8 inch strings by pumping mud fluid through the connection from the gas clamps. The gas clamps used wore of ordinary construction with a side outlet, making them equivalent to a Braden-hoad. When the mud fluid was pumped through the gas clamp into the space between the two strings, it began to appear inside the 6-1/4 inch string. It apparently entered the well either around the toothed shoe or through a "line sawed" leak in the string and was blown out of the well as fast as it was pumped in. In order to stop the leaks, about a half a gunny sack of finely chopped bull ropa was fed with the mud between the casings as before. The hemp gathered around the valves of the mud pump to some extent, and it also stuck in the casing-head fittings a few times. An obstruction in the casing- head would be removed by permitting the woll to "blow back" for a few seconds, and one in the pump valves, by removing the valves when necessary. In two days' time sufficient hemp and mud had been pumped into these strings to kill external and internal pressure. The wall was shut in and allowed to stand over night. The next day, by opening and closing the master gate at intervals,

Mar 1, 1921

By D. A. O'Keefe, M. M. Wong

To obtain beryllium metal of higher purity , flakes produced from electrorefining scrap metal were used as cell feed for a second cycle of electrore fining at 500 ° C in an electrolyte composed of 51.7 mole - percent LiCl , 36.9 molepercent KC1 , and 11.4 mole - percent BeC¹ · Metallic impurities in the flakes totaled more than 108 ppm , the metallic impurities in the metal obtained from the two - cycle electrorefining were , with the exception of 35 ppm of calcium , below the spectrographic determination limits .

Jan 1, 1964

By Dennis Dolinar, Christopher Mark, Gregory M. Molinda

In 1999, 2,087 unplanned roof falls were reported from 841 mines. Nearly 55% of all mines reported at least one roof fall, and nearly 17% of the mines reported five or more falls. In order to investigate the variables that contribute to roof falls, the National Institute for Occupational Safety and Health (NIOSH) compiled a national database of roof performance from 37 coal mines. Geotechnical factors and their effect on roof fall rates were compiled from over 1,500 miles of drivage. The factor that is the best predictor of roof fall rate is the Coal Mine Roof Rating (CMRR). For a low CMRR (#30), almost all cases have high roof fall rates. Conversely, high roof fall rates are rare for strong roof rocks (CMRR $ 60). Roof fall rates were also higher in deeper mines, probably because of greater stresses. Intersections were much more likely to fall than roadways, and four-way intersections were more prone to fall than three-way intersections. In a controlled comparison of the effect of increasing bolt length on roof fall rates, it was found that longer bolts reduced the roof fall rates in 11 of 13 cases. A relationship between the roof fall rate, the intersection span, and the CMRR was also found. Finally, a systematic method for tracking roof performance and geotechnical variables was demonstrated.

Jan 10, 2000

Improve the safety of roof bolting machine operators working in underground coal mines while maintaining or improving efficiency of the roof bolting operation. Approach The Bureau of Mines funded research under contact to develop equipment that would assure greater safety in drilling holes and installing roof bolts. The research led to the design and fabrication of a roof-boiling machine that allows its operator to per-form drilling and bolting tasks while under permanently sup-ported roof or canopy protection. How the Prototype Works The major components of the remote-control roof bolter are a flexible-shaft drill that provides continuous drilling capability without the need to Stop to add drill extensions for long holes; a roof-bolt inserter that can bend a longer-than-seam height roof bolt into the drilled hole; and a roof-bolt lifter/torquer that completes insertion of the roof bolt into the hole and torques it to the desired tension.

Jan 1, 1986

By C. A. Herbert

"The Workman's Compensation Law of Indiana, enacted in 1915, amended in 1917, 1919, 1923, and 1927, and in 1929 named the Indiana Workmen's Compensation Act of 1929, provides for a weekly compensation for disability due to accidents of 55 per cent of the average weekly wage of the employee, to start on the eighth day of disability. Compensation is computed from a maximum and minimum weekly wage of $30 and $16, respectively. Thus, the maximum weekly compensation is $16.50 and the minimum $8.80; the total compensation paid is not to exceed $5,000.In addition to the compensation the employer is required to pay all medical, surgical, hospital, and nurse fees for a period of 30 days and may be required to pay such fees for an additional 30 days at the direction of the Industrial Board of Indiana. In the case of fatalities the employer must contribute $100 toward funeral expenses.The law also stipulates that ""the employer shall keep a record of all injuries, fatal or otherwise, received by his employees in the course of their employment,"" also that the employer shall report within one week of their occurrence all accidents that cause either the death of the employee or the loss of more than one day's work. However, no standard form is furnished or required by the industrial board on which the employer shall keep a record of accidents, neither is he required to report the time of return to work of the injured employee unless the period of disability exceeds seven days and the accident thus becomes compensable. Hence, no record is kept of noncompensable accidents other than the first report sent to the industrial board by the employer.If the employer were required to keep a complete and concise record of all accidents, in duplicate, on a special form either furnished or required by the board, giving all of the essential data in regard to the accidents, and if he were required to submit a copy of this record to the board at the end of the fiscal year, the data thus assembled would not only be of material assistance to the board, particularly in making up its annual report, but would also furnish information of much value in the study of accident causes and what may be done to remove them.Those industries that have made marked progress in reducing accidents keep such records, as it is only through a full knowledge of how accidents occur that intelligent steps can be taken to prevent their recurrence. Unfortunately, the mining industry as a whole in Indiana has not kept pace with many other industries in reducing accidents, and it is urged as an aid to improvement that a thorough and complete record of mining accidents be kept."

Dec 1, 1932

By J. M. Stuve

The standard heats of formation (?Hf°) of holmium trichloride and terbium trichloride were measured by solution calorimetry. Heats of solution of holmium and terbium metals and their anhydrous chlorides were measured in 4.360 molal HCI at 298.15° K. From these measurements ?Hf° for HoC13 (c) was calculated as -240,290 ±1,700 cal/mo1e, and ?Hf° for TbC13 (c) was calculated as -238,330 ±1,500 cal/mole at 298.15° K.

Jan 1, 1967