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By M. M. Tilman

A series of alloys was laboratory prepared by adding up to 4 weight-percent cobalt to the basic composition of type AM 350 (AISI 633) stainless steel. Aging curves were established for each alloy at 750° F, 850° F, and 950° F for lengths of time up to 100 hours. A series of annealed steels containing as much as 1 weight-percent cobalt was cold-rolled 50 percent and aged for 3 hours at 850° F. No improvement in hardness due to cobalt was observed in the steels transformed by heat treatment. Slight improvements in hardness were observed in the steels transformed by cold working.

Jan 1, 1968

By J. W. Horne

The quantitative determination of salt in petroleum ins generally divided into two steps - (1) extraction of salt from the oil and (2) accurate measurement of the extracted salt. This paper presents a method used by the Bureau of Mines for quantitatively extracting the water-soluble chloride salts4/ from petroleum and discusses important details attendant on the success of the method. Among these details are homogeneity in the dispersion of salt crystals, emulsified brine and other impurities in the oil sample, complete solution of the salt, and total extraction and titration of all the aqueous phase. Recently, the chlorides of sodium, calcium, and. magnesium produced with and present in various oils have developed growing problems of salt deposition and corrosion in the petroleum industry. Therefore, a technical study of various emulsions and salts that accompany petroleum is being made by the Bureau of Mines in cooperation with the State of Oklahoma. One report (5)5 reviewing the literature pertinent to the study has been published.

Jan 1, 1940

By W. L. Staker

Alternatives were developed to the conventional ammoniacal carbonate leaching-steam stripping procedure for recovering copper as an oxide from contaminated scrap metal. By entraining air bubbles in the leach solution, the copper dissolution rate was increased to 1.5 g/in2 of copper surface per hour, compared to 0.5 g/in2/hr produced by conventional agitation in stirred tanks. Using entrained nitrogen gas bubbles for agitation in conjunction with powdered sulfur not only resulted in rapid dissolution but also simultaneous precipitation of the copper from solution as a high-grade cuprous sulfide.

Jan 1, 1971

By J. W. Horne

The quantitative determination of salt in petroleum ins generally divided into two steps - (1) extraction of salt from the oil and (2) accurate measurement of the extracted salt. This paper presents a method used by the Bureau of Mines for quantitatively extracting the water-soluble chloride salts4/ from petroleum and discusses important details attendant on the success of the method. Among these details are homogeneity in the dispersion of salt crystals, emulsified brine and other impurities in the oil sample, complete solution of the salt, and total extraction and titration of all the aqueous phase. Recently, the chlorides of sodium, calcium, and. magnesium produced with and present in various oils have developed growing problems of salt deposition and corrosion in the petroleum industry. Therefore, a technical study of various emulsions and salts that accompany petroleum is being made by the Bureau of Mines in cooperation with the State of Oklahoma. One report (5)5 reviewing the literature pertinent to the study has been published.

Jan 1, 1940

By George J. Conroy, Angel G. Jordan, Eugene W. Bartel

Time-domain reflectometry has long been an accepted and used method for locating electrical faults in electrical cables. The process has, however, required the use of equipment that is somewhat complex and difficult to use. The skill level needed to operate such equipment is high. Therefore, the use of the time-domain reflectometry process has been limited to selected locations and controlled environments. The process, however, has great potential for mine system applications. The ability to locate and repair trailing power cable without removing it from the mine would result in great savings in cost and employee-hours. Therefore, an automatic microprocessor-controlled time- domain reflectometry system was developed to reduce process complexity and skill level needed to operate the unit. The theory of operations is discussed along with the computer analogies used in the unit. The present unit capabilities are presented and future areas of application and research are discussed.

Jan 1, 1979

By Nicholas T. Zilka

One mineral deposit in the Golden Trout Wilderness has potential. The currently producing Pine Tree Mine on the Little Kern River has an estimated 120,000 tons (109,000 t) each of indicated and inferred reserves averaging 0.77 percent tungsten trioxide. No apparent potential exists for base or precious metal or other mineral deposits. INTRODUCTION The Golden Trout Wilderness, established by Congress in 1978 under Public Law 95-237, encompasses 240,000 acres (97,000 ha) of conifer-forested, rolling, upland plateau at the headwaters of the Kern River in Inyo and Sequoia National Forests (fig. 1). Abundant streams locally contain Golden Trout, namesake of the area. Major roads serve the area to the west and east of the Wilderness; access is poor to the north and south.

Jan 1, 1982

By C. M. Mason

A method for evaluating the relative incendivity of detonating cord in natural gas-air mixtures was developed. The method consisted of firing short lengths of cord in bundles to determine the number of strands per bundle which would ignite natural gas-air mixtures 50 percent of the time in the 45-cubic-foot gallery of the Bureau of Mines. The relative efficiency of a flame quenching agent, potassium acid tartrate (KHT), when incorporated in both the pentaerythritol tetranitrate (PETN) core and the polyethylene sheath, was explored. The effects of sheath thickness, sheath composition, core weight, and core composition were evaluated. The bundle method established a quantitative scale for evaluating the relative incendivity of cords. The relative incendivity determined by the bundle method was then compared with the incendivity of 100-foot lengths of detonating cord when initiated in 8 percent natural gas in the 640-cubic-foot gallery of the Bureau of Mines.

Jan 1, 1968

By Oliver Bowles

It is noteworthy that 80 to 95 per cent of the gross production of all slate quarries in the United States is discarded as waste . In view of the loss involved in handling so much waste , and the consequent added cost of the finished product , the Bureau of Mines has undertaken a study of the slate industry for the purpose of devising the best means of reducing the proportion of waste , and of utilizing the unavoidable waste . The utilization of waste has received special attention , and the cooperation of many prospective purchasers of waste slate has been enlisted in testing its adaptability for various uses .

Mar 1, 1921

By George S. Rice, L. C. IlsLey

"A remarkable explosion of fire-damp caused by a discharge of lightning at the new shaft at the Sitalpur coal mine, has been reported by the Chief Inspector of Mines of India, who gave the following details:""The explosion occurred during a thunderstorm, and the evidence showed that a flash of lightning had, to all appearances, passed down the shaft caus¬ing disruptive discharges at certain points between the guides and the winding rope, rending the latter at two places situated respectively .228 .feet and 278 feet from the surface, The distance between the winding rope and the side of the shaft was 5 feet 4 inches, indicating a spark gap ;of this width, and an intensity of discharge which could not fail to ignite the explosive mixture of gas and air known to be present in the shaft.""The Compressed Air Magazine, January 1920 issue, which contained the above extract also goes on to state;""In 1915, M, Ferey described in a paper read before the Societe de l'Industrie Minerale phenomena of a similar character to the above. In a pit liable to sudden outbursts of gas, for the sake of safety, shot firing was carried out from the surface. During a storm, in the year 1905, shots went off in two places after the detonators had been connected to the conductors) we read in the Colliery Guardian, London. These shots were situated respectively 1,400 and 1,410 metres from the firing station, Realizing the possible danger from this cause, the precaution was taken to cut the conductors at the bottom of the shaft and to connect there just before firing, Even under these conditions a shot went off spontaneously, -.owing, it is believed, to lightning."""

Feb 1, 1920

Provide the U.S. mining industry with the means to measure and control exhaust emissions of diesel engines used in underground mines. Approach Diesel research is divided into four primary areas: exhaust aerosol measurement, particulate control, gaseous emission control, and chemical and biological characterizition of particulate matter. Diesel research is frequently cosponsored by industry; collaborative research ventures between industry, academia, other government agencies, and the Bureau arc common. Diesel research at the Bureau is conducted in the diesel engine research facility at the Bureau?s Twin Cities Research Center (TCRC). This facility is a state-of-the-art laboratory capable of performing emissions testing, exhaust control evaluations, and safety tests. Background Exposure of mine workers to airborne contaminants from diesel engine exhaust is potentially harmful. The National Institute for Occupational Safety and Health has recommended that whole diesel exhaust be regarded as "a potential occupational carcinogen" and that ?reductions in exposure to diesel exhaust in the workplace would reduce the risk." The U.S. Mine Safely and Health Administration (MSHA) convened an Advisory Committee on Standards and Regulations for Diesel-Powered Equipment and is beginning to implement its recommendations, which cover health, safety, and certification and approval issues surrounding the use of diesels underground. In January 1992, MSHA published an advance notice of proposed rulemaking to regulate diesel particulate matter in underground mines.

Jan 1, 1992

By D. R. Tesarik, R. W. McKibbin, J. B. Seymour

Displacement and stress changes in cemented backfill and ore pillars at the Buick Mine, near Boss, MO, were monitored by engineers from the U.S. Bureau of Mines and The Doe Run Co., St Louis, MO. A test area in this room-and-pillar mine was backfilled to provide support when remnant ore pillars were mined. Objectives of this research were to evaluate the effect of backfill on mine stability, observe backfill conditions during pillar removal, and calibrate a numeric model to be used to design other areas of the mine. Relative vertical displacements in the backfill were measured with embedment strain gauges and vertical extensometers. Other types of instruments used were earth pressure cells (to identify loading trends in the backfill), borehole extensometers (to measure relative displacement changes in the mine roof and support pillars),and biaxial stress meters (to measure stress changes in several support pillars and abutments). Two- and three-dimensional numeric codes were used to model the study area. With information from these codes and the installed instruments, two failed pillars were identified and rock mass properties were estimated.

Jan 1, 1995

By W. F. Marshall

The effect of engine parameters on exhaust emissions from two diesel engines was studied experimentally. Fuel-injection characteristics and intake air conditions were considered as parameters influencing the emissions. Emphasis was placed on the effect of parameter variations on nitrogen oxide (NOx) emissions, because diesels generally emit very low levels of carbon monoxide (CO) and unburned hydrocarbons. Emissions other than NOx were at lowest levels when the engines were adjusted for best performance. NOx emissions can be diminished somewhat through variation in fuel-injection characteristics, but there generally are penalties in emissions of CO, smoke, and unburned hydrocarbons or in engine performance. Temperature and composition of intake air have a significant effect on NOx emissions. Levels of NOx are reduced by recirculating the exhaust gas or by adding water to the intake air stream. However, the rate of water added or exhaust gas recirculated must be limited to prevent the degradation of engine performance and increased emissions of CO and smoke. At high exhaust recirculation rates, levels of CO and smoke were increased such that it was necessary to derate the engine and also to use a catalytic system for oxidation of CO.

Jan 1, 1971

Provide an improved, rugged, reliable, cost-effective automatic fire protection for mine haulage trucks. Approach Systems that automatically sense and extinguish fires on haulage trucks were designed, built, and in-mine tested. How It Works Temperature sensors mounted above the engine of the truck detect the heat from a fire while it is still small and controllable. A cab-mounted control panel warns the operator of the fire emergency and then automatically triggers the discharge of 60 pounds of multipurpose dry chemical extinguishing agent (from storage tanks through hoses and nozzles) into the engine compartment. If desired, the control panel can be field-adjusted by changing one resistor to delay the discharge for up to 60 seconds to allow time for the operator to stop the truck and shut down the engine. The system can be assembled with either pressurized storage tanks, or a combination of non-pressurized storage tanks plus separate pressure cartridges. This pressure source option is one of the improvements of this system over the earlier systems described in Technology News No. 11. Other improvements are a simplified control circuit and an improved sensor.

Jan 1, 1980

By John C. Edwards

Chapman-Jouguet detonation calculations were carried out for pentaerythri-tol tetranitrate (PETN), TNT, and ammonium nitrate-fuel oil (AN-FO) explosives using the compressibility form of an equation of state of hard spheres based upon Percus-Yevick (PY) theory, and a chemical equilibrium detonation code called TIGER. Similar calculations were also carried out with the Becker-Kistiakowsky-Wilson (BKW) equation of state. For PETN, the BKW equation gives somewhat better agreement with experimental values of detonation velocity and pressure. However, in terms of experimental temperatures and concentrations of the minor product species (NO), the predictions of the PY equation are shown to be more satisfactory. Similar comparisons of experimental and theoretical results for TNT and AN-FO indicate that the PY equation has general utility in predicting the detonation properties of condensed explosives at moderate loading densities (Po < 1.3 g/cm3).

Jan 1, 1974

By A. W. Kbair, L. D. Gehl

"INTRODUCTION The rock-bit interaction during the cutting process in underground mines has been a matter of great concern to mining operators, researchers and manufacturers, particularly after the passage of strict environmental laws. Coal cutting bears directly on airborne coal dust generation and rock cutting generates frictional sparks which may cause face ignitions, jeopardizing the productivity, safety and economy of the industry. It is imperative to investigate into the factors which have influence on bit we.ar. Hurt and Evans (1981) concluded that the point attack bits have greater ignition potential than the conventional wedge shaped bits, and also worn bits were more responsible for ignition than the new bits. The results of a study (Khair et al., 1992) suggested that after 7% weight loss, the bit should be replaced. The polycrystalline compact diamond (PDC) tipped bits are reported to be cost effective in a study done by USBM (Twin Cities Research Center), and it was stated that the PDC tipped drill bits had 80 to 100 times longer life than the ordinary tungsten carbide (WC) tipped bits.This paper presents the results of the experiments which were conducted utilizing a coal cutting simulator at the laboratory of the Department of Mining Engineering, West Virginia University, USA. The description of the machine and the experimental set-up have been described elsewhere (Khair et al., 1989; Gehi & Khair, 1994), and therefore, will not be discussed here. The rock types which were used in experimen~ are Tennessee sandstone, Berea sandstone and Indiana limestone. The operating parameters include (1) drum speed, (2) water spray pressure and (3) bit type. Besides studying the wear characteristics influenced by the above mentioned variables, the effect of these parameters on the required cutting force, specific energy consumption, acoustic emissions rate and rise in temperature of the bit were also studied. A preliminary study was also done to compare we.ar characteristics of the WC bits with those of the poly-crystalline compact diamond tipped bits."

Dec 1, 1995

By D. Harrington

"The fire boss in coal mining and the shift boss in metal mining, though held responsible to a large extent for safety of underground employees and of the mine, are, it seems to me, not always vested with sufficient authority nor given compensation commensurate with their duties. The metal-mine shift boss, although his position as regards his relations between employer and employee, is frequently an unenviable one, has as a rule much more authority than the fire boss and is not expected to perform the menial tasks required of the latter by many coal-mining companies.In most coal-mining States the coal-mine foreman and the fire boss are re¬quired to possess a certificate of competency obtained by passing an examination. The foreman is legally responsible for the safety of the miners, as in most instances the superintendent is not required to pass an examination. Although the foreman is held legally responsible for the safety of the miners, the law does not, in general, compel the superintendent or other higher officials to delegate sufficient authority to the foreman to enable him to put his wishes or judgment into effect; and this condition has tended in many instances towards perpetuation of unsafe conditions.The fire boss is held legally responsible for conditions in his ""beat"", but he is generally given only such authority as the mine foreman sees fit to delegate, frequently very little, Moreover, the fire boss is generally required to cover his ""beat"" within two hours before the entrance of the underground workers. Only too often his territory is so great that in order to reach all the working faces and chalk the required date at the face, he must travel at a rapid walk or even run. When such haste is necessary to cover the required ground, it is manifestly im¬possible for the fire boss to make a careful inspection or examination of the roof, timbering, wiring, gas, etc., at each place, and doubtless in his hurry many unsafe conditions escape his notice."

Sep 1, 1920

1. In 2002, 14,520 mining operations reported employment statistics to the Mine Safety and Health Administration (MSHA). Almost half (49%) were sand and gravel mines, followed by stone mines (30%), coal mines (14%), nonmetal mines (5%), and metal mines (2%).

Jan 1, 2004

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

APPENDIX C SCALING RELATIONSHIPS 1. Scaling Law for Fly Ash Crater Formation The scaling law derived for predicting crater diameters at different scales is developed below by considering the equation of motion of individual fly ash particles. It is assumed that the air drag on each particle is characterized by Stokes flow, and at the borehole - passage intersection the air velocity and the fly ash particle velocity are the same. The equations of motion for a fly ash particle are the following, (see Figure C-1).

Jan 1, 1973

By Marilyn Biviano

This analysis was conducted in response to concerns raised by the Chairman of the Energy and Commerce Committee of the House of Representatives regarding the potential impacts on automobile production, GNP and employment resulting from embargoing south African supplies of the platinum-group metals, platinum and rhodium. This analysis should be considered an addendum to the recently released study in which the direct economic costs I of a U.S. embargo on selected South African strategic and critical materials are estimated. The estimated GNP and employment impacts result when a mineral shortage reduces domestic industrial production and are in addition to the direct costs estimated in the earlier study. The direct cost to this nation resulting from a decision to embargo six south African strategic and critical minerals was estimated at $1.85 billion per year during the 1988-1992 time frame of the study. The estimated direct costs include the costs to U.S. consumers resulting from higher strategic mineral prices, lower mineral consumption, and the cost of developing higher cost domestic mineral resources. A large proportion of the costs result from the shortage of the two metals: platinum and rhodium. The average direct annual cost of embargoing is estimated at about $1.4 billion for platinum and $384 million for rhodium.2

Jan 1, 1988

By S. Gallagher, A. Mayton, R. Merkel

The prolonged exposure of equipment operators to shock and whole-body vibration (WBV) IS linked to cumulative back, neck, and abdominal disorders. In low-coal mines, space restrictions make seat suspensions difficult to use in isolating operators from shock and WBV. Researchers at NIOSH, Pittsburgh Research Laboratory, are responding to these issues by investigating viscoelastic foams. For the full-load case. an ergonomic seat with viscoelastic foams isolated the shuttle car operator from shock at 15 Hz. Researchers used results from additional foam testing with an analytical model to identify viscoelastic foams that provide shock isolation at a frequency below 5 Hz.