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By Warren E. Morrison

This study was prepared in response to the need for a series of data that reflect the basic flow pattern of energy resources in the United States. To effectively measure and analyze energy,2 it is necessary to prepare balances that reflect both production and consumption, and the various forms energy resources take at different stages of utilization. Before energy can be measured it must also be put into a common unit. In this study the common unit us d is the British Thermal Unit (Btu). The ideal point to survey energy is at the stage of final ultimate use, representing the useful work derived from the interaction of energy inputs and the prime mover. Unfortunately this concept of efficient or useful work from energy output cannot readily be measured in the aggregate. With the present available official data, energy measurement can be carried to the point of calculation of net inputs of energy3 into the economy at various stages of utilization. However, preparation of energy balances, on a net basis is hampered by the fact that this can only be done for years when the censuses of Mineral Industries and Manufactures are taken, usually at 5-year intervals.

Jan 1, 1964

By Richard A. Thomas, Isaac A. Zlochower, Gregory M. Green, Kenneth L. Cashdollar, Martin Hertzberg

This paper reports the results of flammability studies for methane, propane. hydrogen, and deuterium gases in air conducted by the Pittsburgh Research Laboratory. Knowledge of the explosion hazards of these gases is important to the coal mining industry and to other industries that produce or use flammable gases. The experimental research was conducted in 20 L and 120 L closed explosion chambers under both quiescent and turbulent conditions, using both electric spark and pyrotechnic ignition sources. The data reported here generally confirm the data of previous investigators, but they are more comprehensive than those reported previously. The results illustrate the complications associated with buoyancy, turbulence, selective diffusion, and ignitor strength versus chamber size. Although the lower flammable limits (LFLs) are well defined for methane (CH,) and Propane (CA), the LFLs for hydrogen (HZ) and its heavier isotope deuterium (D2) are much more dependent on the limit criterion chosen. A similar behavior is observed for the upper flammable limit of propane. The data presented include lower and upper flammable limits, maximum pressures, and maximum rates of pressure rise. The rates of pressure rise, even when normalized by the cube root of the chamber volume (V 1/3), are shown to be sensitive to chamber size.

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

D.2 Principal Types of Coating A Sodium Silicate Sodium silicate is a good fire retarder when freshly applied, but it loses its effectiveness if the relative humidity is at all high, thus exposure to a relative humidity exceeding 65 percent causes a serious decrease in the effectiveness after only one month. In fire, sodium silicate swells to a frothy mass (intumescence) which hardens and insulates the wood against heat. This property is destroyed by exposure to moisture. Manufacturers of many of the proprietary paints containing silicates state that their products have overcome this difficulty The reagent may be applied alone, or, better, in a mixture with lime-water and common salt, or with inert fillers such as kaolin or asbestos. B Ammonium Phosphate Strong solutions (25 to 35 percent) of monammonium phosphate or diammonium phosphate give good protection. Two or three coats of hot solution should be applied either with a large flat brush or an ordinary paint spray gun The solution should be applied as hot as possible, as this improved penetration, and it should be the aim of the operator to apply 4 lbs of reagent, i e , one gallon of 33 percent solution to every 100 square feet of surface

Jan 1, 1976

By Jr. Dubaniewicz, Gregory M. Green, Kenneth L. Cashdollar

Laser-based instruments are used in areas where coal dust ignition presents a safety hazard. The National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory ~NIOSH, PRL! is conducting a study to help determine when an optical beam may be considered a potential ignition source in underground coal mines or coal storage facilities. Researchers conducted experiments to determine threshold igniting powers for Pittsburgh seam bituminous coal dust clouds using an 803 nm continuous wave laser. For fine sized coal dust dispersed in air, concentrations ranging from 600 to 2000 g/m3 were the most easily ignited. A heated layer of coal dust that deposited on the fiber tip during dispersion ignited the dust clouds. Minimum observed igniting powers for laser beams delivered by 200, 400, and 800 mm core fiber optic cables and directed into coal dust clouds were 2.0, 3.0, and 5.0 W, respectively. Threshold igniting power was proportional to beam diameter, and threshold igniting power density decreased with larger fiber diameters. Ignition delay times averaged 0.6 s and did not vary significantly with laser power under initially turbulent test conditions and with flammable targets. Comparisons are made with the results of other researchers.

By J. W. Thompson

CONVEYANCE OF COAL IN PLACES. Coal or other mineral in place may be granted and conveyed as land, separate and apart from that which underlies or overlies it. Board, etc., of Greene County v. Lattas Creek Coal Co., 100 Northeastern, 561 (Indiana), January, 1913. MINERALS SUBJECT OF GRANT. Coal, mineral, and stone under the surface of the earth are the subject of grant and exception, and when excepted in a deed become a separate and distinct inheritance. Gordon v. Million, 154 Southwestern, 99 (Missouri), February, 1913. CONVEYANCE BY ONE COTENANT. One cotenant of land can not make a valid conveyance as against his cotenants of the minerals therein and a right to the small timber on the surface necessary for mining purposes with easements and full rights of way over the premises by the construction of roads, tram- ways, or railroads for the purpose of extracting, storing, handling, and shipping the mineral products. Ball v. Clark, 150 Southwestern, 359 (Kentucky), November, 1912. CONTRACT OF SALE COVENANTS RUNNING WITH LAND. Where a deed was made pursuant to a contract for the sale of certain copper-mining property at an agreed price, and at the same time and as a part of the same transaction a written agreement was

Jan 1, 1913

By A. L. Murray, D. Harrington

From 1870 to the end of 1929 the coal production of Utah has been some- what less than 110,000,000 tons. During this period at least three major disasters have occurred with fatalities totaling about 380, establishing a decidedly bad record of approximately 3.5 persons killed by major mine explo- sions per million tons of coal produced. Even during the period when there have been no disasters, such as the years 1914 to 1920, inclusive, the fatalities in ordinary working were about 5.4 per million tons produced, against 3.7 per million tons for the whole United States for the same years. The 5-year period following the World War, 1918 to 1922, inclusive, had 4.7 fatalities per million tons; hence, the fatality record in the coal mines of Utah has uniformly been in excess of the average of the coal mines of the entire country. Notwithstanding this poor record, Utah has given to the coal-mining world many excellent safety methods and practices, and Utah coal mines in general take greater measures toward safe mining than do the coal mines of any other State; if practices and methods allowed and pursued in coal mines of other States were tried in Utah coal mines, there would be a succession of disasters.

Nov 1, 1931

Although early Spanish settlers used coal several centuries ago, significant commercial coal mining in New Mexico began in 1861, when the U.S. Army opened a mine to supply Fort Craig. Since then, coal from the state has been used to fuel railroads, lead and copper smelters, and other local industry. In recent years, lower-cost strip mining methods and an increased demand for coal by electric utilities in the Southwest have caused an increase in New Mexico coal production. The coal-bearing regions of New Mexico underlie about 25,000 square miles or20.6 percent of the total area of the state. However, the majority of coal-bearing regions lie under Indian lands that are regulated by the Office of Surface Mining (see Navajo and Hopi data on pages 72-75). Today, most of the coal produced in New Mexico comes from the San Juan Basin in the northwest part of the state and the Raton Area in the north central part. New Mexico's reserves are estimated to be 4.6 billion tons, about one percent of the national reserve. New Mexico's permanent regulatory program was conditionally approved December 3 1, 1980. Its Abandoned Mine Lands Program was approved July 17,198 1.

Jan 1, 1992

By Alan G. Mayton

A prototype end-cab shuttle car (SC) design has been developed to improve protection and address ergonomic concerns of the SC operator in low coal mines. The new design features an end cab transversely mounted to the SC and equipped with a closed-circuit video system. The end cab was retrofitted to a low-coal SC and evaluated in surface trials at the U.S. Bureau of Mines. During surface trials, test operators evaluated the end-cab SC relative to visibility; cab features-space, seating, controls, and operator position; tramming-inby, outby, and turning corners; and dumping. Trials were conducted using 12 test subjects; 6 were experienced SC operators. Results of the trials were promising. Of the experienced operators, the only operator with low-coal experience gave the new design the highest rating. Four experienced operators rated the end-cab design "better" to "much better" than a standard center-driven, side-cab SC for visibility when tramming, protection from roof and rib hazards, and no change in seat position with direction of travel. This report discusses research to modify a used 21SC JOY SC, retrofit the SC with the Bureau-developed end-cab, and evaluate the retrofitted end-cab SC in surface trials.

Jan 1, 1993

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

D. 1 Most Effective Salts A. Ammonium Phosphates Monammomium phosphate and diammonium phosphate (salts of ortho phosphoric acid) are superior to the triammonium salt in fire-resisting properties. Of these two, the monammomium salt is chemically the more stable. It is also held very retentively by a number of woods, thus reducing leaching out of the salt if exposed to water. Saturated aqueous solutions of mon- or di-ammonium phosphates have vapor preservatives corresponding to an atmospheric relative humidity of 9Z to 93 percent, the wood, will, therefore, not attract any moisture at humidities below this figure. Low concentrations (1 lb dry fire-retardant per cubic foot of the dry, treated timber) will stop flame and high concentration (5 lbs. per cubic foot) will prevent smoldering. B. Ammonium Sulphate In low concentrations ammonium sulphate has only a small effect on flame propagation, but its effect is marked when concentrations of the order of 20 percent are employed. It has no appreciable effect on smoldering. It is more corrosive to metals than are the phosphates, but is less corrosive than ammonium chloride or magnesium chloride. It is possible to leach it out of wood by prolonged and continuous action of water The vapor pressure of the saturated solution corresponds to 81 percent atmospheric humidity.

Jan 1, 1976

By Michael A. Trevits

Mine fires can be especially perilous because toxic products can quickly spread well beyond the fire zone thereby exposing all underground miners to dangerous and deadly conditions. Since November 1998, there have been six major underground coal mine fires or explosions in the United States (Willow Creek (twice), Sanborn Creek, Loveridge No. 22, West Elk and the Jim Walter Resources No. 5 Mine). In each case, the entire mine or specific areas of the mine had to be sealed due to the build-up of dangerous gases and the fear of uncontrolled spread of the fire. Effective placement of mine seals can deprive a mine fire of oxygen and is often followed by water flooding or injection of inert gas into the affected area. When access to the fire zone is impossible because of safety reasons, airtight mine seals can be constructed, in the area of the fire, remotely from the surface through vertical boreholes. Remotely constructed mine seals are commonly made from cementitious material. Since these mine seals are typically erected blindly, it is difficult to determine if mine roof-to-floor and rib-to-rib closure has been obtained. This paper provides a review of the available materials and technology used to remotely construct mine seals through vertical boreholes.

Jan 1, 2002

By John L. Reuss

A laboratory study was conducted by the Bureau of Mines to investigate the technical feasibility of decomposing hydrous magnesium chlorides by using a steam pyrohydrolysis technique. This procedure consisted of injecting steam into the atmosphere of a decomposition furnace containing samples of hydrous magnesium chloride and determining the rate of hydrolysis by measuring the rate of chloride evolution. The variables investigated were temperature, amount of water vapor in the decomposition atmosphere, and hydration stage of magnesium chloride. The application of steam was shown to accelerate both the rate and completeness of magnesium chloride decomposition reactions. For example, when magnesium chloride hexahydrate is exposed to a furnace temperature of 600' C in an air atmosphere for 20 minutes, the decomposition is 37 percent. Under identical conditions in a steam atmosphere, the decomposition is in excess of 70 percent. The magnesium oxide produced by the steam pyrohydrolysis of magnesium chloride dihydrate at 800° C contained 98 percent magnesium oxide. Based on magnesium oxide composition, this is equivalent to that of burned magnesite produced at temperatures in excess of 1,300° C. To demonstrate the quality of the product on a practical basis, metal reduction tests have shown it to be equivalent to reagent-grade magnesium oxide as a carbothermic reduction feed material.

Jan 1, 1974

Improve the field-of-view into the front-right blind spot for drivers of large haulage trucks, thereby reducing the growing collision hazard in surface mines. Approach Reduce the glare problem found in the first generation fresnel lens blind area viewer design by eliminating the upward-looking section of the fresnel lens and adding a rear hood to reduce backlighting. How It Works The first generation blind area viewer was developed and in-mine tested as an aid to improved visibility for large haulage trucks. Other aids were improved left-and right-hand mirrors. Evaluations showed that a blind area viewer mounted on the right-front of the radiator deck was effective and was readily accepted by drivers. Nevertheless, because glare was a problem under certain conditions, a low-profile viewer was developed. Glare control louvers from the earlier design were kept and a backlighting glare control hood was added. The height of the hardware was reduced by eliminating the top three inches of the fresnel lens. This portion of the lens contained an upward-looking segment which originally was thought to be needed so the driver could see the horizon when he looked through the viewer and be better

Jan 1, 1982

Permit quicker, safer clearance of hang-ups in the ore passes and chutes of underground mines. Approach Develop a device that can be operated from a safe distance to explosively propel a projectile into the hang-up. How It Works The Hang-Up Clearance Module, consisting of a stand, steel disk, explosive charge, and aiming device, is placed at a location convenient for line of sight aiming at the hang-up. This placement can be more than 100 feet from the target. Once aimed, the charge is remotely detonated, and the disk is converted by explosive force into a slug and propelled to the hang-up, bringing it down. The steel disk and an explosive charge are contained by a plastic casing. A small booster which is placed at the rear center of the explosive makes up the last component of the charge. Initiation is accomplished by standard means such as detonating cord or a number 8 blasting cap. When Initiated, a detonation wave travels through the explosive, inverting and consolidating the steel disk into a large slug. This slug is propelled at high velocity to the hang-up, delivering more than 5 million foot-pounds of energy on impact.

Jan 1, 1981

By Sean Gallagher, Thomas G. Bobick, Diane M. Doyle-Coombs, Richard L. Unger

The U.S. Bureau of Mines has developed an in-house facility to evaluate selected effects of whole-body vibration (WBV) levels experienced by underground mobile equipment operators, Vertical vibration data were collected from a coal haulage vehicle via a uniaxial accelerometer attached to the machine frame under the operator&apos;s seat. Data were analyzed and processed so a computer-controlled platform could approximate the vibration signals. Eight men (35.5 yr 2 6.5 SD) participated in a pilot study to evaluate the effects of shock and kBV on heart rate (HR), blood pressure (BP), and subjective discomfort. Subjects were exposed to vibration for 30-min periods while seated in a typical seat (backrest angle at 90° or 130°) &apos;that was plain steel or modified with 2 in foam padding. Subjects repeated the same protocol on a separate day, without the vibration. Results indicated the vibration significantly increased the HR (Q< 0.01), systolic BP, mean BP, the number of times subjects reported discomfort, and overall subjective discomfort rating (pc 0.85). When seated in the steel seat, the overall discomfort rating (E< 0,081) ad the number of times discomfort was reported (p< 0.05) increased significantly. Seatback angle had no significant effect on any of the dependent measures.

Determine the dust reduction capabilities of various bag valves available to the minerals processing industry. The Problem Many different types of ground mineral products are packaged into 50-and 100-lb paper bags. Although bag technology is continually improving, dust contamination from bags still remains a significant problem for workers. The greatest source of dust is the bag filling valve. Ideally, the bag filling valve should close after it fills the bag with the ground mineral product. However, the valve usually fails to close properly since some mineral product gets trapped inside the valve during filling and ejection. As a result, when the bag has been filled and falls from the fill station, a rooster-tail of product is discharged from the bag valve. As the bag hits the conveyor belt, additional product discharges from the bag valve. The dust from these sources contaminates the air inspired by the workers filling the bags as well as the work area. Dust also clings to the outside of the bag, contaminating the pallet loading station. Because the various commercial bag valves are composed of different materials, a dust analysis was performed on five of these valves to determine their dust reduction capabilities. The five valves analyzed were: standard paper, polyethylene, extended polyethylene, double trap, and foam.

Jan 1, 1986

By A. F. Colombo

In an effort to maintain an adequate supply of iron to meet national economic and strategic needs, the Bureau of Mines, U.S. Department of the Interior, is conducting research on methods for beneficiating the oxidized taconite resources located on the western Mesabi range in Minnesota, thus expanding domestic iron ore reserves. The selective flocculation and cationic flotation process was investigated in a pilot plant using an ore feed rate of 410 kg/hr (900 1b/hr) and 88 percent recycled water. Lime and a cationic flocculant were used to clarify the waste slurries treated in the water reclamation circuit. An oxidized taconite assaying approximately 36 percent Fe yielded concentrates averaging 63.5 percent Fe and 4.3 percent SiO2 and having an average iron recovery of 84.4 percent. The estimated reagent cost per tonne of concentrate was approximately $1.10. In an attempt to recover more of the iron lost in the flotation tailing, wet high-intensity magnetic (WHIM) separation was incorporated in the pilot plant circuit. The flotation concentrate grades obtained from beneficiation circuits with and without WHIM scavenging were similar, but when WHIM separation was used the overall iron recovery was increased by 2 to 9.5 percent, depending on the iron assay of the flotation tailing.

Jan 1, 1978

By John H. Scott

At the request of the Mine Safety and Health Administration, U.S. Department of Labor, the Bureau of Mines evaluated the model BT 300 C-D blasting machine tester, manufactured and distributed by Research Energy of Ohio, Inc. (REO), to determine whether the tester performed as stated by the manufacturer and responded satisfactorily to electrical faults introduced into the blasting machine circuit. Tester readings were recorded for 13 blasting machines and for 12 circuits constructed to simulate the electrical parameters of actual machines. The tester readings were acceptable for all of the blasting machines, although the switch position assigned to one machine produced an off-scale reading. The tester responded satisfactorily to the simulated circuits and detected serious voltage or capacitance faults when they were introduced. However, it did not respond accurately to certain resistance faults. Temperature tests were also made, and the tester performed equally well at temperatures of 20°, 42°, and 81° F. This tester was judged a useful accessory for field checking blasting machines for defective batteries and capacitors, despite its limitations. It is recommended that the tester manufacturer specify the lowest acceptable reading at which a blasting machine may be used and below which the blasting machine should be returned to the laboratory or manufacturer for maintenance.

Jan 1, 1981

Provide reasonably priced, reliable fire protection for AN-FO haulers. Approach An automatic fire sensing and suppression system for AN-FO haulers was developed and on-vehicle tested. How It Works The system works in two ways to protect personnel from dangerous and unpredictable AN-FO fires. First the system senses and suppresses fires on the truck before they spread to the AN-FO in the bunker. This design was chosen because AN-FO truck fires generally start when combustible liquids (such as diesel fuel, hydraulic fluid or lubricating oils) are ignited by hot surfaces mainly on three areas: the engine, the transmission or the power take-off. These fires are quickly sensed by a linear temperature sensor strung throughout these three areas. The system then warns the operator and automatically suppresses the fire by discharging 30 pounds of multipurpose dry chemical extinguishing agent through a network of fixed hoses and nozzles. Second, this system includes six spot thermal sensors mounted inside the bunker on the truck to monitor the AN-FO temperature in case a fire does spread to the bunker area. If the bunker temperature rises to 190° F, a loud siren is sounded to warn nearby per-

Jan 1, 1981

By Robert F. Chaiken

A novel approach to eliminating environmental and public safety hazards that are associated with fires in abandoned coal mines and waste banks involves the use of in situ combustion technology developed by the Federal Bureau of Mines to accelerate the burning of the wasted coals in place. This technology would be used under exhaust ventilation control conditions that would allow for total management of the hot gases produced. Combustion stoichiometries would be optimized to minimize unburnt combustibles and to maximize the heat content of the gas products, which will be exhausted at one or more fan locations. When necessary, scrubber systems would be employed to remove air pollutants, such as sulfur dioxide; heat utilization systems (process heat, steam, and electricity) would also be employed to offset operational costs. Ultimately, complete burnout would solve the fire and acid water formation problems of the abandoned coal mine or waste bank. Pertinent technical data for burnout control are derived and discussed in terms of the important material and operational parameters. In general, it is believed feasible to operate a burnout system in an existing abandoned mine or waste bank fire at thermal power levels in the range of 10 to 100 Mw, and at exhaust gas temperatures of 1,000° C (1,830° F).

Jan 1, 1980

By Paul Sands

Single- and two-stage tests were made with 6-inch, coal-cleaning hydrocyclones to determine the effect of hydrocyclone geometry, operating conditions, and feed composition on performance. Most of the testing was conducted in an open-circuit pilot plant that had a maximum capacity of about 9 tons per hour. The coals used in the investigation had top sizes of 1/4 inch and 28 mesh. Considerable latitude was found in the range of geometry variables that could be used without affecting performance adversely, although a certain minimum ratio of overflow to underflow openings had to be maintained for best operation. Two-stage cleaning proved distinctly better than operation with a single hydrocyclone, because clean coal lost in the refuse product of the primary unit can be partly recovered in the secondary. There is an unusually great difference in the specific gravities at which the individual sizes of the feed are separated in the hydrocyclone. This militates against high efficiency because maximum yield occurs when all sizes are cleaned at the same specific gravity. The size composition of the feed and, more particularly, the size composition of the impurity have a greater influence on the efficiency attainable in the hydrocyclone than in most other types of fine-coal cleaners.

Jan 1, 1968