Search Documents

By Gary E. Sherman

Preliminary economic mining feasibility studies were conducted by the Bureau of Mines to estimate mining costs in the Juneau gold belt area of the Juneau Mining District, southeastern Alaska. Investigations were conducted on the economics of two mineral deposit types: (1.) Berners Bay vein gold deposits, and (2.) stockwork gold deposits containing gold, silver, and lead. Cost estimates were developed using the Bureau of Mines Cost Estimating System (CES). Discounted cash flow return on investment (DeFROI) was calculated using the Bureau's MINSIM computer program. Underground mining of a Berners Bay vein gold deposit was found to be economic (15 pct DCFROI) at a recoverable metal value of $353.67/mt for a 100 mtpd shrinkage stoping mine with a 10 yr mine life, $324.76/mt for a 20 yr mine life, $138.63/mt for a 500 mtpd longhole stoping mine with a 10 yr mine 1 ffe, and $127.50/mt for a 20 yr mine life. Block caving mining of a large stockwork gold deposit was found to be economic at a recoverable metal value of $15.28/mt for a 18,000 mtpd mine with a 20 yr mine life.

Jan 1, 2011

Objective The main purpose of this video is to teach mine rescue personnel certain aspects of rescue work that are not traditionally taught. These include the strain caused by working continually under adverse conditions; the "survivor guilt" that occurs from being spared the fate of one's deceased cohorts; and the posttraumatic stress that may be experienced during the sometimes lengthy task of recovering the victims' bodies. Background On November 20, 1968, an explosion rocked the Farmington No. 9 Mine in northern West Virginia (figure 1). The explosion killed 78 of 99 miners who were working in the mine, including all but one member of the mine's rescue team. Some 30 years after the event, researchers from the NIOSH Pittsburgh Research Laboratory (PRL) conducted a video interview with Danny Kuhn (figure 2), the only Farmington No. 9 mine rescue team member who was not working that day and who did not die in the explosion. According to the Mine Safety and Health Administration (MSHA), there are about 80 underground coal mine rescue teams in the United States, and according to the National Mining Association, there are more than 850 underground coal mines. This represents a significant decrease in both over the past decade. The low number of rescue teams is a concern because serious incidents, though fewer, still happen, and if a disaster occurs, there will be fewer rescue teams to respond. This would result in an increased need to use available human resources very efficiently. Much training to prepare these rescue teams still takes the form of what educators call "teaching to the test." In other words, teams practice in order to win mine rescue contests. This test-oriented approach has traditionally been augmented by interactions with others who have responded to real situations or by participating in actual incidents. Given few incidents and fewer rescue teams from whom to derive enrichment, the preparation of coal mine rescue personnel becomes a problem. Recently, more emphasis has been placed on active learning, such as working out problems in smoke. These sessions more nearly simulate the actual conditions that today's team members might rarely encounter. To properly prepare and retain the current coal mine rescue personnel who are left in the workforce, it is necessary not only to offer such hands-on experience, but also to replace the learning narratives that once were passed from team to team. The present video is intended to contribute in that capacity. Approach NIOSH researchers first learned of Mr. Kuhn in the fall of1998. Mr. Kuhn was contacted and agreed to an interview. An oral history interview was conducted with Mr. Kuhn in early November1998. After reviewing the videotape of the interview, researchers determined the content to be so rich as to warrant a second interview in a more formal setting. The second interview was done in early December 1998. During this interview, Mr. Kuhn spent about 2 hours describing the Farmington disaster, including the workplace climate leading up to the explosion, the events that took place in the 10 days after the explosion, and the nearly 10-year effort to safely and successfully recover most of the victims' bodies. The videotape of the second oral history interview with Danny Kuhn was reviewed and edited by NIOSH researchers for content. Careful attention was used to ensure that valuable information was presented, but within a reasonable timeframe. A detailed map of the Farmington No. 9 Mine was edited into the final video and used to highlight critical features as they were being described by Mr. Kuhn. Results and Accomplishments A 60-minute videotape and instructor's guide for use in safety training or other settings was completed. The target audience consists of all those who work in underground coal mines. This training video will help safety instructors better prepare mine rescue team members for the situations that they will encounter when engaging in extended rescue and recovery work. As a result of this expectations training, team members will be more likely to serve their

Mar 1, 2002

By R. A. Franks, J. C. Edwards, L. Yuan

To determine the critical air velocity for preventing smoke rollback, diesel-fuel fire experiments were conducted in the National Institute for Occupational Safety and Health’s (NIOSH) Pittsburgh Research Laboratory’s Safety Research Coal Mine. Such information is necessary for preplanning and implementation of ventilation changes during mine fire fighting and rescue operations. The fire intensity varied from 50 to 300 kW depending on the fuel tray area. Airflow in the 2-m- (6.6-ft-) high, 2.9-m- (9.5-ft-) wide coal mine entry was regulated during the course of each experiment. The airflow was measured upwind from the fire as an average over the entry cross-section with an ultrasonic airflow sensor and was recorded dynamically with a mine monitoring system. The extent of smoke reversal was monitored with light-obscuration monitors, ionization smoke sensors and visual observations. Experimental results for the critical air velocity for smoke reversal as a function of fire intensity compared very well with model predictions based upon a computational fluid dynamics fire dynamics simulator.

By Forrest T. Moyer

INJURY experience and employment data are presented in this chapter for metal and nonmetal mines, stone quarries, sand and gravel pits, iron blast-furnace slag plants, and metallurgical plants (including ore-dressing and nonferrous reduction plants and refineries) in the United States. Employment and injury experience data for all mineral industries are given in volume II. The 1962 figures are preliminary summations which are subject to revision. They were compiled from all reports from producers received by the Bureau of Mines through April 15, 1963. The data for metal, nonmetal (except well and brine operations), stone, and sand and gravel operations were collected by a mandatory reporting system under the provisions of the act of September 26, 1961, Public Law 87-300 (75 Stat. 649). The act authorized the Secretary of the Interior to study the various aspects of safety in metal and nonmetal mines (excluding coal mines) and report the findings 2 years sub-sequent to the enactment of the law. Data on nonmetal well and brine plants and nonferrous reduction plants and refineries were reported voluntarily by the operators. METAL MINES Preliminary data for the metal mining industry comprise reports on 1,871 mines and pits. The combined fatal and nonfatal injury-frequency rate was 31.95 per million manhours in 1962, a decrease of 8 percent from the similar rate of 34.54 in 1961. Metal operations reported a total of 61 fatal and 3,201 nonfatal injuries.

Jan 1, 1963

By J. W. Eckerd

The crushing of chestnut-size (1-5/8 by 13/16 inch) Pennsylvania anthracite in four commercial crushers (impact) jaw) hammer-mill) and gyratory types) was studied by the Bureau of Mines to determine which could produce the largest proportions of buckwheat Nos. 1 and 2 sizes (9/16 by 3/16 inch). Single pass dry and wet crushing techniques and the effect of stage crushing were evaluated. Calculations were made to show the effect of closed-circuit reduction on production rates and yield of the various sizes. The data show that the gyratory crushers produced the greatest percentage of the desired sizes. A ring-type hammer mill produced the greatest tonnage of buckwheat No.1 and rice (14.9 tons per hr.) during dry grinding tests) but the yield of these sizes was only about 55 percent) as compared with 62 to 70 percent for the gyratory crushers. The impact and jaw crushers produced the smallest amount of buckwheat and rice and the largest quantity of oversize material.

Jan 1, 1960

By T. M. Ruff, W. G. McCoy, M. J. Beus, S. Iverson, W. Hasz

Technology to enhance safety during mine hoisting has been developed by researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health. Assessment of current hoisting technology suggests that monitoring conveyance position and load directly from the skip or cage top offers several significant safety advantages. Wireless data transmission schemes and a package consisting of sensors, batteries, and a charger mounted on the wire rope and skip have been developed. A state-of-the-art automated hoisting test facility was constructed to test the concept in a controlled laboratory setting. Field tests in a fill-size shaft are underway.

By Travis Q. Lyday

Mineral production in Fiji, a group of 322 volcanic islands and atolls of Melanesia in the southern Pacific Ocean, continued to be dominated by gold. However, the Fijian mineral sector remained a minor factor as a source of export earnings, Government revenues, and employment, generating only 1% of the gross domestic product (GDP), estimated as $1.2 billion.2 The largest and most important mining operation was the Vatukoula gold mine on the north side of Viti Levu, the main island. The Vatukoula Mine has been in prduction since 1932, producing about 3.8 million troy ounces of gold and 1.3 million troy ounces of silver to date. In April 1983, the large Australian mining firm, Western Mining Corp. (WMC), assumed operation of the mine in a joint venture with Emperor Gold Mining Co. Ltd., which operated the mine previously. The WMC takeover of the mine management was expected to bring in additional capital and technological expertise in order to modernize operations, increasing both efficiency and output. During the year, rate of recovery was only about 75% of the gold contained in the ore and only 40% of the contained silver. Mining at the Vatukoula Mine was done using bath opencut and underground methods, with about 60% of the ore mined attributed to the underground operations.

Jan 1, 1985

By Travis Q. Lyday

During 1981, Ecuador's gross domestic product (GDP) increased by a reported 4.8% in real terms, a slight improvement over that of 1980. In current prices, the CDP in 1981 was estimated at $13.7 billion.2 The inflation rate increased to 15.6% according to official figures, above that of 1980. Ecuador's production of petroleum increased 3% in 1981 compared with that of 1980. The consortium of Corporación Estat al Petrolera Ecuatoriana (CEPE), the state oil company, and Texaco, Inc., produced almost 98% of the total from their Putumayo Basin operations in Oriente, the eastern jungle region. In sharp contrast, output from the Santa Elena Peninsula Fields, where oil was first produced commercially in 1921, continued to decline, producing only 510,000 barrels, a decrease of almost 8% compared with that of 1980.

Jan 1, 1983

By Michael G. Pojar, John K. Ahlness

"The copper industry has had a long and interesting history associated with leaching, involving vat, dump, heap, and in situ methods. The Bureau of Mines has also had an interest in copper leaching and has researched the techniques of solution recovery, particularly concentrating on in situ methods. In situ mining is a relatively low cost method and has been proven commercially successful by nine operations. It has been most commonly used for final recovery in old workings at the conclusion of conventional mining operations.This report brings together information about 10 commercial in situ operations as well as 14 experimental projects. These 24 sites comprise most of the in situ copper mining activities that have taken place in the United States. Background information, geology, ore preparation, solution application, and recovery and processing are provided for each operation. Production data and tables summarizing the engineering statistics for each operation and an extensive in situ mining bibliography are included. INTRODUCTIONThe purpose of this Bureau of Mines report is to summarize the documented in situ copper leach mining activities that have taken place in the United States. It was prepared to provide a source of engineering and operating data upon which future in situ copper mining activities can be based. Twenty-four different sites are discussed. These are all of the sites that are known to the authors from the extensive in situ copper leach mining bibliography developed at the Bureau's Twin Cities (MN) Research Center (Appendix B).In situ copper leach mining activities fall into the following categories:1. Commercial operations with ore body preparation.2. Commercial operations in old mine workings.3. Experimental programs.Ore body preparation includes such activities as blasting, block caving, and hydraulic fracturing (hydrofracing) specifically to fragment the ore body. Operations in old mine workings include those done in open pits, worked out block caved areas, and backfilled stopes where leaching is done as an afterthought to conventional mining. Experimental programs are small-scale tests of the feasibility of a commercial operation. Some of these programs did not progress to the point where leach solutions were applied to the ore.Each operation (locations shown in figure 1) will be discussed in terms of background information, geology, ore preparation, solution application, recovery and processing, and engineering and production data. Information was collected from published reports, communications with company personnel, and site visits."

Jan 1, 1982

Objective To develop safety training tools for mine safety and health trainers that can be used for both new-miner training and annual refresher training. Background For the past 3 years, NIOSH has been developing training materials for mine safety trainers in response to gaps identified during stakeholder meetings. Most materials have been directed to the hazards of underground mines, but the recent passage of Part 46 of CFR 30 required new-miner and annual refresher training in aggregate operations. One result was the identification of another audience needing basic information about safety in mining. Trainers characterized trainees in this segment of the industry primarily as young males, many of whom had little work experience. Approach Training specialists from the Arizona State Mine Inspector’s Office approached NIOSH researchers early in2002 about the possibility of a collaborative project to develop safety training materials for new trainees in aggregate operations. A preliminary search of MSHA accident statistics identified over a dozen common hazards that could be targeted in a training video. A storyline was developed for review by safety specialists in the aggregate industry, and a script was written to cover the selected hazards. Although the target audience was primarily new hires, the finished video was also to be relevant to more experienced workers.

Jan 1, 2003

By J. R. Thoenen

This circular is the second of a series presenting methods employed in solving the technical problems encountered in the production of sand and gravel. The first paper3 discussed the methods use in prospecting and exploration. This one teals with the problems involved in bringing a raw prospect to the production stage and considers the various methods of development and the Factors affecting that development. Later publications are planned to present and discuss methods of recovery and treatment. The recovery of sand and ravel from natural deposits and their preparation for market involve a progressive sequence of operating steps or processes. Each step or process presents its own peculiar problems which require different angles of mental approach, methods, and tools, but all are more or less dependent on the step or process which precedes or follows.

Jan 1, 1933

By F. A. Rutledge

The Batesville district in north central Arkansas is one of the important sources of manganese ore and ferruginous manganese ore in the United States, with a history of production dating back to 1849. From studies by the Federal Geological Survey, it was recognized that the district probably still contains substantial reserves of low-grade ore. It was natural, therefore, that the deposits in this area should be among the first investigated by the Bureau of Mines under the Strategic Materials Act of June 1939, by which the Bureau was authorized to explore domestic deposits of strategic minerals, at that time designated as those of antimony, chromium, manganese, mercury, nickel, tin, and tungsten. The field work of the Bureau of Mines in the Batesville district was done in two distinct phases. Under project 308, active from August 1940 to June 1941, carbonate-oxide ores were investigated at five separate areas in which 100 trenches, test pits, shafts, and edits aggregating 4,364 linear feet were excavated and 839 samples were taken and assayed. Under project 323, in progress from February 1941 to January 1942, wad deposits were explored at 10 separate areas by 408 prospect shafts, churn-drill holes, and bucket-drill holes aggregating 23,680 linear feet from which 285 samples were taken and assayed. Processes for beneficiating the wad ores were investigated at ore-testing laboratories of the Bureau of Mines.

Jan 1, 1952

By Charles W. Huggins

A study of the high magnification of some inorganic fibers which are found in nature or produced in the laboratory, has been conducted with the electron microscope. This series of electron microqraphs shows the important morphological differences exhibited by potassium-lead silicate, lead-aluminum silicate, chrysotile, wollastonite, silicon nitride, potassium titanate, cobalt chrysotile, magnesio-fluor-richterite, fluor-richterite, refractory oxide fiber, silicon carbide, massive serpentine, and palygorskite. A ribbon or a thin lath 250-2500 A. wide is the structural form of potassium-lead silicate and lead-aluminum silicate. Chrysotile, cobalt chrysotile, and massive serpentine all have a tubular structure and a fairly uniform (150-300 A.) diameter. Wollastonite, potassium titanate, fluor-richterite, and magnesio-richterite crystals have a lath shape, and potassium titanate laths are laminated ribbons. Single fibers of silicon nitride and palygorskite are ribbons, and the silicon nitride sample contains many twins (branching fibers). Palyqorskite fibers are highly flexible and have cross-sectional measurements of 150-300 A. Silicon carbide fibers differ from other fibers because their structure consists of several different forms. The sample used in this study had, predominately, a margarite-type structure. The refractory oxide fiber lost, all its apparent fibrosity after being prepared for electron microscopic examination, and only irregular fragments are visible in the electron micrographs.

Jan 1, 1962

By M. A. Trevits, J. E. Urosek, A. C. Smith, M. P. Valoski

Unlike other types of mining accidents, where an incident generally involves only a few workers, the danger of a mine fire extends to every person working in the underground environment. Mine fires can trap or kill those working underground by blocking avenues of escape and rapidly creating heat, asphyxiating gases and toxic fire products that can quickly spread throughout the mine. The National Institute for Occupational Safety and Health (NIOSH), in partnership with the Mine Safety and Health Administration (MSHA), is conducting research to test, evaluate and improve or modify coal mine fire-fighting strategies and methodologies through large-scale tests. Because wood is the second most abundant fuel available during a coal mine fire, it was decided that a series of large-scale wood crib fire tests was needed to measure the products of combustion and to observe the capability of commonly available direct application fire suppression equipment, namely, fire extinguishers, water and gas-enhanced foam. This paper discusses the wood crib fire tests, provides insight into the products of combustion and describes observations made during the application of the fire suppression agents.1

By George S. Rice

"""To prevent the propagation of mine explosions, the Bureau of Mines, Department of Commerce, recommends rock-dusting all coal mines, except anthracite mines, in every part, whether in damp or dry condition. It also recom¬mends that rock-dust barriers be used to sectionalize the mine as additional defense; but these should not be regarded as a substitute for generalized rock-dusting."" (Mine safety decision, No. 5, April 7, 1927.)The purposes of this circular are to present concisely the requirements for effective rock-dusting of coal mines in order to prevent propagation of mine explosions, and to point out the principal related facts on explosibility of coal dusts and mixed coal-mine dusts, as determined by extensive testing in the Experimental Mine of the Bureau of Mines. study of these principal facts on coal-dust explosibility in conjunction with the recommendations for rock-dusting, should help to make clear to mine operators and others concerned the necessity for systematic rock-dusting in all coal mines except anthracite mines, and the futility of inadequate or sporadic rock dusting.The descriptions of nearly 1000 explosion tests in the Experimental Mine are available in a forth-coming bulletin2 and in earlier publications.3For detailed specifications as to the kind of rock-dust, amount to use, where to be applied, and method of sampling and testing, the reader is referred to Bureau of Mines Serial 26064, and American Engineering Standard Committee ""Recommended American Practice for Rock-Dusting Coal Mines"" quoted in Bureau of Mines Information Circular No. 60305.Summary of Specifications for Rock-Dusting1. Mines to be rock-dustedAll coal mines, except anthracite mines, should be rock-dusted.2. Extent of rock-dustingAll open accessible parts of a coal mine should be rock-dusted, including slopes, entries, cross,-cuts, and rooms, headings and pillar workings to within at least 50 feet of the face.3 Amount of rock-dustingAfter cleaning up the coal dust as thoroughly as practicable, sufficient rock-dust should be used to have the mixture of remaining coal-dust plus the rock-dust in any zone contain 65 per cent or more of inert or noncombustible matter. First dusting may require 3 pounds to 5 pounds per linear foot of passageway.4. When to rock-dust In any zone or section (made by dividing the mine for rock-dusting purposes) when the incombustible content falls to 55 per cent, that section should be re-rock-dusted so as to bring the incombustible content well above 65 per cent."

Jun 1, 1927

By Pablo Velasco

After becoming an oil exporter in 1972, Ecuador experienced a remarkable economic upswing until 1978. However, in 1979 and 1980, a combination of only slight improvements in agricultural output and stagnating petroleum output lowered rates of real gross domestic product (GDP) expansion to 5.3% and 4.3%, respectively. In current prices, the GDP in 1980 was estimated at $11.3 billion.2 The slowdown in growth is attributable in large part to the low level of petroleum exploration in the 1972-79 period. Ecuador's production of petroleum declined 4.5% in 1980 compared with that of 1979. The consortium of Corporación Eatetal Petrolera Ecuatoriana (CEPS), the State oil company, and Texaco, Inc., operating in Ecuador's eastern jungle region was responsible for nearly all of 1980 production, The volume of total crude petroleum exports from Ecuador dropped from 44.7 million barrels in 1979 to 40 million barrels in 1980, although crude petroleum export revenues rose from $1,032 million in 1979 to $1,294 million in 1980- The latter figure represented 54% of Ecuador's 1980 merchandise exports. Crude oil exports accounted far about 46% of the value of 1979 merchandise exports. The total nonfuel mineral exports in 1980 were valued at less than $1 million.

Jan 1, 1982

By R. L. Zick, J. D. Byars, T. P. Mucho

Recently, a large Pittsburgh seam longwall mine was nearing depletion of a major portion of its current reserves and had begun to develop in a different direction from its original portal area to access additional reserves. This meant that a large area of the mine would be abandoned and sealed. However, continued use of the original mine portal area required that the water accumulating in the abandoned mine would eventually need to be pumped to the surface. This would be in addition to the discharge water associated with the new portion of the mine. Several pumping and sump options were investigated to handle the quantity and quality of the anticipated discharge water. This paper describes some of these options, their advantages and disadvantages, and the final engineering decisions. Some problems and unanticipated outcomes, as well as the eventual solutions are discussed, including: (1) estimates of pump requirements, (2) water pool size, (3) eventual water quality, (4) anticipated inflows, and (5) integration into the overall mine water system.

By Stephen C. Tadolini, Thomas E. Marshall, Cecil Banta, L. J. Prosser, Anthony T. Iannacchione

The Pittsburgh Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) endeavors to provide national and world leadership in the prevention of work-related illness, injury, and death. This is accomplished by using a scientific approach to gather information, assemble and create knowledge, then translate the knowledge and results into products and services. These products and services are then delivered to all personnel who can effect prevention. Obviously, the development and use of instruments to monitor mine roof conditions provides an opportunity to execute that mission. In the late 1990’s, based on observations at a number of underground limestone mines, only a few used roof monitors. Subsequently, NIOSH introduced the Roof Monitoring Safety System (RMSS) as an aid to roof inspection beyond traditional visual and sounding techniques. Initial expectations were that by gaining roof movement information, ultimately roof sag rates could provide indications of eventual failure. During this investigation, RMSSs were installed in 13 underground limestone mines in six states and this paper analyzes the data obtained at three of these mines. This paper also provides an overview of the system, data, analysis, and applications relevant to the RMSS.

By R. Karl Zipf, Francois E. Heuze

Stress analysis programs such as MULSIM/NL, LAMODEL, MinSim 2000, and EXAMINETAB are used in the mining industry to analyze stresses and displacements in coal mines, platinum mines, gold reefs, and tabular-type deposits. These relatively simple numerical models can efficiently simulate yielding and failure of a rock mass near a mine opening and subsequent stress transfer. The main input parameters for these models are a family of nonlinear stress-strain curves for the in-seam material. For many applications of these models, such as in coal mining, extensive field measurements and observations exist from which to estimate these stress-strain curves and calibrate the numerical models; however, such measurements are lacking for other types of mines. A three-step method is presented to determine nonlinear stress-strain curves for boundary-element (BE) programs used in many mining applications. The method requires a suite of laboratory-scale strength tests at various confining pressures. Note that this analysis uses laboratory-measured strength and modulus properties of alluvium. The dependency of the mechanical properties of alluvium on scale has not been established, although more tests are being planned. However, it is believed that the relative comparisons performed are valuable regardless of scale effects. First, the FLAC2D computer program is used to model the laboratory tests and determine cohesion (c) and friction angle () for a Mohr-Coulomb material model. Second, another FLAC2D model uses the c and values to calculate vertical stress and strain around a single opening in the rock mass. This model calculates the stress-strain path of points at various distances from the opening boundary. Finally, based on these stress-strain paths, the stress-strain curves needed for a BE analysis are derived. This three-step method was demonstrated in a large, flat-lying underground test facility in very weak rock. The BE analyses agreed well with observations of failure at the test facility and provided a basis for evaluating the behavior of alternative layouts.

By Richard J. Mainiero, James H. Rowland

When most people think of explosives transport they think of a hazardous operation. We all know that we aren’t allowed to transport explosives through tunnels and are discouraged from traveling through heavily populated areas. Popular opinion suggests that explosives transport is a very risky operation. The authors decided to look into this a little more thoroughly and found just the opposite to be true. While there have been some disastrous world-wide accidents involving the transport of industrial explosives, this is not the case in the U.S. Over the past 10 years, accidents related to the transport of explosives used in mining and construction have resulted in 5 major injuries, 11 minor injuries, and no fatalities. Explosives and ammonium nitrate (AN) transport outside the U.S. has not had such a good record; there have been 4 major explosives or AN transport accidents resulting in a total of more than 300 deaths. Most of these fatalities could have been prevented if the accident site had been evacuated once the explosive or AN cargo began burning. The safe history of explosives and AN transport in the U.S. is due to diligent efforts by government, labor, and industry. However, accidents will become more common and disastrous if we become complacent.