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

C. 4 Hoist Assemblies (not man-rated) A large number of manufacturers supply materials handling winches. These units are predominately electric powered while a limited number of vendors supply air powered equipment. Air powered units are currently used extensively for underground materials handling purposes. Suppliers of materials handling equipment normally include a disclaimer statement in their published literature which clearly states that the equipment "is not designed or suitable for lifting or lowering persons " This category of commercially available equipment can be adequate for emergency man hoisting provided that its' capacity is suitably derated and provided also that the necessary safety features are incorporated. Section C. 5 details the equipment which could be added to a commercial materials hoist to meet these needs. Four commercially available hoist assemblies, two electric and two pneumatic are discussed in the following paragraphs. This equipment is typical of what is commercially available and three of the units are currently used extensively in mining applications. Each hoist description includes a remarks paragraph which identifies the additional equipment each hoist would require for emergency hoist use.

Jan 1, 1976

To develop an explosive charge that will effectively break rock in underground mines and that can be safely fired without the use of blast-holes or the need for stemming. Approach The Bureau of Mines developed a non-incendive, cylindrically-shaped explosive charge that will not ignite gassy or dusty atmospheres, even methane-laden air. How It Works Firing unconfined explosive charges in underground mines is prohibited by law since detonation in gassy or dusty atmospheres is extremely dangerous. However, there are advantages in using unconfined charges from both a safety and a production standpoint. Explosives can effectively break up large boulders, rocks and slabs when leveling roof falls and can dislodge overhangs which miners would other-wise have to dislodge manually, exposing themselves to

Jan 1, 1983

To reduce front-end loader (FEL) collision accidents by detecting obstacles in the rear blind area. The Problem Federal regulations require an audible backup alarm to activate when an FEL is backing. Since the device is constantly being activated, the warning soon becomes a normal part of the mine environment and is less effective as a warning device. Also, when several machines are working together, it is difficult to detect by ear alone just which machine is backing. Approach The Bureau defined the location for hazard detection to include an area extending 15 to 20 ft behind the rear bumper of an FEL. Then, existing surveillance and detection technology was assembled, ruggedness, and applied to the FEL's rear blind area to form a new discriminating backup alarm system employing either infrared light, ultrasonics or radar

Jan 1, 1986

By Robert C. Hickman

"INTRODUCTION The Big Four fault and the Sandy Creek fault, with several cross faults, traverse the Stalion-Curnel fluorspar prospect in a northeasterly direction. The Big Four mine, about three-quarters of a mile northeast of the prospect, is the only active mine in the immediate area.A resistivity survey was made of a portion of the prospect by the Division of Geophysical Exploration, Bureau of Mines, in May and June 1946. As a result of this survey, five holes were drilled by the Bureau of Mines during the period from October 8 to December 16, 1946. Two Longyear No. 12 Junior Straitline diamond drills were used for the work.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each project as soon as practicable after its conclusion. The Mining Division, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Division, Oliver C. Ralston, chief, analyzes samples and makes beneficiation tests.The project was under the supervision of Mitchell H. Kline, chief, Raleigh Branch, Mining Division."

Mar 1, 1948

Control dust generated during overburden drilling at surface coal mines using either wet suppression or dry collection systems. Approach For the wet suppression systems, a range of water flow rates was tested over a number of holes. Each hole was drilled at a specific and constant flow rate. A recording flow meter was mounted in the water line near the control system pump. For the dry collection systems, each drill was tested with the front of the shroud set at different heights above the ground. Because of the irregularity of the ground surface, all height measurements were taken at the front of the shroud. Background Wet drilling systems consist of a water tank mounted on the drill from which water is pumped into the downhole air line. The water droplets in the bail air conglomerate dust particles as they travel up the the annular space of the drilled hole, thus controlling dust as the air bails the cuttings from the hole.

Jan 1, 1987

By P. W. Jeran, M. C. Irani, D. H. Lawhead

The Beckley mine is one of five new mines in a heretofore unmined portion of the Beckley coalbed. The remoteness of these new mines from prior mining and their greater overburden preclude applying methane emission experience obtained in the old mines. Four sections of the Beckley mine were monitored. The data gathered show that variations in methane emission cannot be explained by variations in coal production. Although overburdens varied by as much as 30 pct, no correlation with methane emissions could be determined. The rib emissions increase with increased length of rib from a section advancing into virgin coal and do not decline over a prolonged idle period (32 days) whereas some decline has been measured for a section not mining into virgin coal. The indication is that degasification prior to mining will reduce the hazard of methane emissions in this area of the Beckley coalbed.

Jan 1, 1977

By C. Travis Anderson

"A recent critical study by Ralston3 of the iron system points out the importance of and necessity for work upon the preparation of ferrous oxide. Not only are ferrous oxide samples desired for determination of the important physical and chemical properties, such as specific heats and heats of formation, bat also information on the stability and behavior of this material is of considerable technical importance. Related. problems where the properties of Fe0 are important have to do with desulphurization of iron, the formation and occurrence of magnetite in copper smelter slags, and sulphur elimination in copperFerrous oxide also has valuable catalytic properties, as is demonstrated in nitrogen fixation.Pure ferrous oxide has never been prepared in quantities large enough to furnish adequate physical and chemical data on its properties. Only two or three experiments4 have produced a fraction of a gram in a state approximating purity and have collected evidence that has been sufficient proof of their having done so. Ferrous oxide is stable only above about 570°C., and below that splits into magnetite and iron according to the reactionUp to about 1920, those who had endeavored to prepare FeO made no provision for rapid chilling, so that although their product. may have had the proper iron oxygen ratio for FeO, in reality it-probably did not consist of pure FeO. The above reaction is reversible; above 570oC. magnetite and iron are supposed to recombine almost completely, and if so, should constitute a direct and easy method of preparation. The data, however, were somewhat conflicting, and the extent to which the reaction goes in either direction needed checking. Preliminary experiments on the interaction of molten Fe304 with solid Fe gave Fe0 of about 85 per cent purity, corresponding to. the approximate purity obtained by some previous investigators. The present work is concerned chiefly with the results cf repeated interaction between partly reduced magnetite and iron, and the calculations which may be made from such results. Repeated treatments are necessary, because molten impure ferrous oxide and iron can not be kept in contact for more than short periods of time."

Oct 1, 1928

By John A. Davis, John Gross

This paper is one of a series giving the results of metallurgical tests conducted by: the Alaska station of the Federal Bureau of Iſines, on the recovery of gold from the black sands of placer clean-ups. The data given in this report were obtained from tests on a lot of black sand from a property located on St. Patrick Creek, Fairbanks mining district, Territory of Alaska. This property comprises the Sagan Fraction and adjoining bench claims, and is being operated by J. A. Lillie. The sand ad already been treated at the mine by amalgamation. A sample taken by Mr. Lillie and assayed at the station showed that the gold still remain ing amounted to ll cents per pound. As this gold content was sufficiently high to justify further treatment of the same, 770 pounds were shipped to the station for testing. The reader will note that the gold content is given in cents per pouni, rather than per ton. This is in conformity with practice in the district in valuing black sands, as the quantity obtained at any one time is small, much less than one ton. . The sand consisted principally of schist and quartz, with very little ilmenite and garnet; and no magnetite or sulphides. Most of the gold present as contaminated with quartz, as the free particles of gold had been removed by amalgamation at the mine.

Sep 1, 1920

By J. J. Bourquin, S. H. Katz

"Three types of respiratory apparatus namely, gas masks, hose masks, and self-contained oxygen-breathing apparatus - are now commonly used for protection from noxious gases, vapors, and smokes or ristes, but no particular type can be selected as best for all conditions. Many factors must be considered in connection with each situation, so that each must be considered as a problem in itself. Following are concise statements for comparing the types:Gas masks are the simplest and easiest to wear, also the least cumber-sore; but they protect only in comparatively low concentrations of noxious gases and should never be used where the air contains less than 16 per cent of oxygen. Special masks give protection from one gas or class of gases, but may give no protection against another gas or class of gases.Hose masks protect in any irrespirable atmosphere, but are somewhat cumbersome, the length of hose limiting the distance a wearer may go from fresh air. They are serviceable also where a supply of pure air moves with the wearer, as where a locomotive engineer in a smoky tunnel is using a hose mask supplied with air from the compressed air line of the locomotive. Hose masks consume no chemicals or materials and so are not limited in the time they may be used.Self-contained oxygen-breathing apparatus protect in any irrespirable atmosphere, but their weight is cumbersome, they can be used only by trained men, and frequent attention must be given them to maintain good working condition. On the other band they are the only safe means for exploring mines and other places filled with irrespirable gases in high concentrations."

Jun 1, 1923

By D. Harrington

Examination of numberous disasters , such as fires or explosions , and the evidence at coroner's inquests following such disasters in several States , have shown the writer how frequently men in charge of the operation and safety of mines have forgotten, or have failed to learn , details of safe mining practices , After securing a position of trust as superintendent , or a certificate of competency to act as shot -firer , fire boss , or mine foreman, some men seem to have felt it unnecessary to keep safety principles in mind , or to keep abreast of current progress in safety ; they have concentrated on getting out maximum tonnage at minimum cost . • In coroner's inquests , the testimony after disasters has shown that firebosses , foreman , and coal -mine superintendents are noticeably lacking in knowledge of the provisions of the State mining law relating to fans or doors , frequency of crosscuts , nature of stoppings necessary , electrical equipment , records of daily mine examinations , quantity of air required , or splitting and overcasting .

Jul 1, 1922

By Harry Dobroski, Larry G. Stolarczyk

A medium-frequency (MF) communication system has been built and has been tested in underground mines. It provides radio coverage to vehicles and personnel anywhere in the mine via parasitic coupling into existing mine conductors. The system consists of base stations, repeaters, and vehicular and personnel transceivers. Air-core antennas for vehicles and clamp-on antennas for base stations and repeaters were designed for maximum coupling efficiency using existing mine wiring. Personnel transceivers are of a unique vest design that features a low physical profile, good user comfort, and efficient antenna design. In-mine tests show impressive results. Range between rubber-tired vehicles and base stations is often measured in miles. With repeaters, greater range is possible.

Provide an economic alternative to drill-blast excavation with the same ability to excavate openings of varied orientation, shape, and size. Approach Develop an efficient, adaptable, mechanical excavation machine that produces unconfined tensile failure in rock. How It Works A drill-split fragmentation machine that combines a drill and a unique splitter has been developed. The drill and splitter are mounted on a carriage that positions the splitter in a hole immediately after it is made by the drill. The splitter creates force loads that cause the rock to fragment, and the process is repeated for excavation. The unique splitter applies both radial and axial loads to the rock mass, which produces an excavation action comparable to pulling a plug. This excavation action distinguishes the radial-axial splitter from typical demolition splitters, which require a free surface parallel to the axis of the splitter toward which to break rock.

Jan 1, 1989

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 Willard L. Hunter

The Bureau of Mines smelted samples of chromite ore and concentrate from the General Services Administration (GSA) purchasing depot at Grants Pass, Oreg., in a submerged-arc furnace to establish smelting conditions and the energy requirement to produce high-carbon ferrochromium. Raw material, in the form of ore, flux, and reductant, and electrical energy are available on the Pacific coast to smelt the chromite. The concentrate can be smelted without prior agglomeration by employing hogged wood (wood chips) as a major portion of the reductant. The energy requirement is relatively low, about 3,960 kw.-hr. per ton of alloy. The ferrochromium produced will contain about 60 percent chromium. In addition to the smelting data, a statistical summary of the grade and amount of chromite purchased during the stockpile program and estimated chromite reserves and production volume are given. It is estimated that 632,000 tons of Cr203 contained in chromite of all grades is available in the western coastal States. Of this total there appears to be sufficient metallurgical-grade and beneficiable ore to sustain a smelting operation for 25 years at a consuming rate of 25,000 tons a year, utilizing material comparable to that delivered to the Government stockpile.

Jan 1, 1961

By J. Roger Loebenstein

ASARCO Incorporated, the only domestic arsenic producer, terminated copper-smelting operations and the associated recovery of byproduct arsenic trioxide at Tacoma, W A. in 1985. It still shipped small quantities of trioxide from its remaining stocks in 1987. Imports for consumption of arsenic trioxide were slightly higher than in 1986. Domestic Data Coverage.-Shipments of small amounts of arsenic trioxide from remaining stocks by Asarco were reported voluntarily to the Bureau of Mines.

Jan 1, 1989

To reduce equipment operator exposure to respirable dust in enclosed cabs by examining the effectiveness of retrofitting air pressurization and filtration systems on existing cabs.

Jan 1, 2001

Use water-jet-assisted cut-ting technology to reduce the exposure of mi ne workers' to respirable dust. Approach Install water-jet-assist on mining machines and evaluate its impact on respirable dust. How It Works Water-jet-assisted cutting involves a mechanical cutting bit working in combination with a moderate pressure (generally up to 10,000 psi) water jet directed just in front of, or through, the bit tip. One of its advantages is reduced dust generation because the jet wets the face of the material being cut more efficiently than a conventional low-pressure water spray, thus capturing much of the dust before it ever becomes airborne. It also removes loose cuttings ahead of the bit before they are pulverized by the bit into respirable dust. Total water consumption is about the same as for conventional low pressure dust control water spray systems. However, there is some increase in power consumption because of the energy needed to provide the high pressure water.

Jan 1, 1987

By Paul T. Allsman

SCIENTIFIC inquiries concerning phenomena that may influence mining technology were widely publicized during the year. The deep-hole drilling project "Moho," 3 the use of nuclear explosives underground, and the recovery of minerals from the depths of the sea became subjects of scientific and general discussion. The mining industry continued to watch these developments with keen interest: but its more immediate concern was the increasing tempo of competition between mineral commodities, the domestic producers of these commodities, and foreign sources of supply. The competitive situation has intensified the industry's efforts to develop more efficient new mining methods, as well as to improve the efficiency of present practices. The attitude of the industry was well illustrated by rapidly expended use of low-cost ammonium nitrate explosives, the establishment of rigid schedules for equipment maintenance, and close attention to the detailed costs of production. The complexity of planning a new coal mine is aptly illustrated by the editors of Mechanization in the April 1959 Issue, in which they outline the cost of developing a mine and the various problems, factors, and decisions involved.4

Jan 1, 1960

By E. D. Gardener, Byron O. Pichard

"Methane, frequently called fire damp or marsh gas, is very well known to coal miners but to thy average gold miner it means nothing, as it is not associated generally with the rock formations in which gold is found.We have recently been conducting a study of mine air in typical gold mines on the Pacific Coast, and out of five California mines in which the air was sampled, three showed methane. Each of these three mines, referred to below as mines A, B, and C, have had accumulations great enough to be ignited. An authentic report from another California, gold mine, which has not yet been sampled, states that recently the superintendent was seriously burned by the ignition of a pocket of gas. This mine is later mentioned as mine D.Mine A is an old mine which had been abandoned for several years and permitted to fill with water. It has been unwaterad recently, and is now being developed at greater depths. During the unwatering, gas bubbles formed on the water and upon being ignited burned freely. It is reported that two men were seriously burned from accidentally igniting the gas. Samples of the bubbles on analysis showed high percentages of methane. Since the mine has been unwatered, no trouble has been experienced through gas being ignited. However, out of a total of six air samples which we took recently in scattered working places, all showed small amounts of methane, the methane content being 0.06, 0.04, 0.05, 0.04, 0.04 and 0.07 per cent, respectively. When these samples were taken methane was not suspected, but its general presence in the mine air indicates that it is being given off constantly."

Dec 1, 1921

By Jay F. Colinet, John A. Organiscak

In This Chapter [Which dust source to address first How much air and water are needed Keeping dust out of the walkway Moving workers upwind Dealing with the stage loader-crusher Gob and wing curtains to aid airflow The shearer-clearer system Modified support movement practices and Dust control for future longwalls ] Controlling longwall dust is not easy. Longwall production levels are high, and there are several different sources of dust to contend with. If dust levels are high, the initial effort should be devoted to finding which source is the cause. Then, efforts to reduce dust can be concentrated where they will have the most impact. To control dust at longwalls, a large amount of ventilation air and spray water must be used. The water must be sprayed correctly so as not to blow dust into the walkway. Techniques to change local airflow patterns can be helpful. The shearer-clearer, as well as gob and wing curtains, are examples of such techniques. DECIDING WHICH DUST SOURCE TO ADDRESS FIRST [If a longwall is out of compliance with dust standards, knowing where the extra dust is coming from helps to get back in compliance quickly.]

Jan 6, 2003