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By A. C. Johnson

The T. L. shaft of the Eureka Corp., Ltd., near Adams Hill, Eureka, Nev., was sunk in 1954 and 1955 to permit exploration and development of the lead-zinc-silver ore that had been indicated by drilling. This paper describes the sinking of the 4-compartment, vertical shaft to a depth of 1,127 feet and includes pertinent details of equipment, methods, and costs. A shaft crew of 10 men, supplemented by 13 hoistmen, topmen, carpenter, and shop crewmen, sank and timbered the 1,127 feet of shaft in 630 workdays. Total labor per foot of shaft was 107.95 man-hours. Supplies per foot of shaft included 20 pounds of explosives, 1.61 pounds of drill steel, and 200 board-feet of timber. Power consumption, including that required for pumping, averaged 3,726 kw.-hr. per foot.

Jan 1, 1958

By Peter G. Kovalchik, Rudy J. Matetic, Susan B. Bealko, Adam K. Smith

Overexposure to noise remains a widespread and serious health hazard in the U.S. service providing and goods producing industries. Excessive noise can lead to poor verbal communication and reduce the ability to recognize warning signals. These dangerous work conditions can also cause stress and fatigue. Occupational hearing loss is a permanent illness, with no recovery currently possible. Method: National Institute for Occupational Safety and Health (NIOSH) has recognized Noise Induced Hearing Loss (NIHL) as one of the ten leading work related diseases and injuries in the United States, and has emphasized its importance as one of the critical areas expressed in the National Occupational Research Agenda. Results: One of the most serious noise problems in the goods producing industries is the operation of continuous mining machines during underground coal mining. In order to minimize occupational hearing loss, noise hazards are “designed out” early in the design process. NIOSH is leading a national initiative called Prevention through Design (PTD) to promote this concept. This paper describes the quiet by design approach of a noise control that reduced noise exposures of continuous mining machine operators by 3dB(A) using the four functional areas of PTD, namely Practice, Policy, Research, and Education.

By R. J. Fantel

The Bureau of Mines investigated the resource availability of titanium minerals from 63 mines and deposits in 12 market economy countries. These mines and deposits contain, at the demonstrated resource level, an estimated 438 million metric tons (mt) of titanium dioxide (TiO2) in the minerals rutile, ilmenite, leucoxene, and anatase. An additional 314 million mt of TiOz is available from inferred resources. If all titanium minerals and other recovered heavy minerals are sold at total costs at least equal to the January 1984 market prices, approximately 200 million mt of contained TiO2 could be recovered in total. In terms of mineral concentrates, this equals approximately 11 million mt of rutile concentrate, 187 million mt of ilmenite concentrate, 3 million mt of leucoxene concentrate, 13 million mt of synthetic rutile concentrate (in addition to the ilmenite), and 89 million mt of titanium slag. The study indicates that world resources of low-cost rutile are declining. In order to maintain future supply for high-grade titanium resources, alternate sources will need to be developed, which may include higher cost rutile mines, Brazilian anatase deposits, increased production from slag operations, or more synthetic rutile capacity from ilmenite resources, which are abundant.

Jan 1, 1986

By R. M. Santmyers

The chief compounds of boron are borax and boric acid, both of which have important applications in industry. At present the United States furnishes more than half of the world's requirements of borate materials, practically all from California. Nearly the entire production of borax in this country is under the control of four companies: The American Potash and Chemical Corporation, the Pacific Coast Borax Co., the West End Chemical Co., and the Western Borax Co.

Jan 1, 1931

By V. T. Dow

This report describes construction details and methods used in driving the 5490 tunnel at the Kennecott Copper Corp, property, Bingham, Utah. The tunnel will provide railroad access to the world-famous open-pit copper mine at the projected 5490 level. This publication is one of a series prepared by the Bureau of Mines to depict mining operations and techniques in various mining districts in the United States. Utah Construction and Mining Go. (formerly Utah Construction Co.), contractor on the tunnel project, began work during September 1956 and completed the project in February 1959. The tunnel is 18 feet wide, 24 feet high, and about 18,000 feet long, It will accommodate a railroad locomotive on standard- gage track. With the exception of the last 1,700 feet, the tunnel is supported by steel sets embedded in concrete lining. The 1,700-fact segment of the tunnel is supported by timber sets that will eventually be removed as the pit is deepened.

Jan 1, 1962

By M. G. Zabetakis, T. D. Moore

The use of a partially slotted 6.5-inch-inside-diameter vertical pipe to remove methane from a longwall gob area at a depth of 2,260 feet in the Pocahontas No. 3 coalbed ms investigated. The value of gas removed by such a pipe under free-flow conditions was found to equal the cost of the installation in this case. Approximately 25 percent of the available methane passed through the pipe without the use of an exhauster; an additional 10 percent was removed when an exhauster was employed. The diversion of methane through a vertical slotted pipe to the surface permitted the use of increased mining rates and decreased the ventilation air requirements.

Jan 1, 1972

By G. L. Oldright, F. S. Wartman

"In the process of smelting copper ores and secondaries in the reverberatory furnace to produce a copper matte and a slag low enough in copper content to be discarded on the dump, it is essential to the best functioning of the process that most of the iron in the material charged into the furnace be at the end in the form of sulphide in the matte or ferrous oxide in the slag. Ferric oxide and magnetite present in the charged material should be reduced to ferrous sulphide or oxide. Ferric oxide offers no difficulty in reduction, at least to the magnetite stage, because it reacts very readily with sulphides at quite low temperatures. Magnetite is less reactive and consequently more resistant to slagging, so that the furnace man must take advantage of all factors favoring its reduction in order to prevent accumulations in the furnace.In order to determine these factors more definitely, the Bureau of Mines in cooperation with the Department of Metallurgy, University of Arizona, has undertaken at the Southwest Experiment Station an investigation of the effect of various factors upon the rate of reduction of magnetite by ferrous sulphide. A previous paper's reported the nature of the reactions taking place and the effect of various physical factors when only pure sulphide and oxide were present. Since in the actual smelting operation, many other substances are also present, it seemed desirable to make a study of the effect of their presence upon the rate of reduction of magnetite by ferrous sulphide. Such a study has been made; the work done and the results obtained are described herewith.As will be shown later, it has been found that of the substances usually present in the smelting charge, silica and magnesia accelerate, whereas lime, alumina, and cuprous sulphide hinder the reduction of magnetite by ferrous sulphide.No report of a previous laboratory investigation of this subject has been found. Almost all furnace operators have made at one time or another at least qualitative ccmparisons of the effect of various changes in operating oonditions upon the behavior of magnetite in the furnace, but the conclusions derived from the experiments have never been published."

Mar 1, 1931

By Lloyd Williams, James R. Boyle

The mining methods and practices used at the Young zinc mine, American Zinc Co. of Tennessee, have resulted in a low-cost, high-yield operation. Zinc ore (sphalerite) occurs in limes tone- dolomi te beds of the Kingsport Formation and is mined by modified room and pillar method. Utilizing trackless mining equipment which incorporates a high degree of flexibility, this operation has had a steady increase in productivity.

Nov 1, 1964

By D. Harrington

"FOREWORDVirtually all government agencies undertook many additional responsibilities during the period immediately preceding World War II; these responsibilities increased vastly in importance and scope after the actual declaration of war following the attack on Pearl Harbor. The Bureau of Mines was one of the agencies thus affected, and it was called upon to perform many duties foreign to its normal peacetime activities.The Health and Safety Division of the Bureau of Mines, at that time designated the Health and Safety Branch, was given several important and difficult duties and responsibilities of an unusual nature because of the war while of necessity-continuing its normal functions of assisting the mineral industries in the preservation of life and health and the protection of property, this being of especial importance in wartime because of the pre-eminent importance of having maximum output of essentially all types of mineral products. Some of these additional functions were given to the Health and Safety Division because the organization of the Division, with its field set-up dividing the Nation into districts with competent, experienced personnel in charge of its work, provided the nucleus of personnel and procedure through which rapid and smooth expanded functioning was feasible.In addition to the responsibilities directly attributable to definite war activities, such as the administration of the wartime Federal. Explosives Act and the Mineral Production Security Branch a new branch (then designated division) was formed to investigate coal-mine health and safety problems after the enactment of the Federal Coal-Mine Inspections and Investigations Act, which became a law on May 7, 1941, but which actually began to function actively after the declaration of war in December 1941.The purpose of this publication is to provide a brief historical record of the activities of the Health and Safety Division as a whole and of its individual branches during the war. The detailed record has been filed in the Archives Building, Washington, D. C."

Jan 1, 1949

By Sterling J. Anderson

Through the use of nondestructive testing techniques, the Bureau of Mines is pursuing a goal of improving the efficiency of the rock excava-tion process. Toward this end, 44 laboratory tests were conducted to identify a practical method of monitoring fracture development in rock, as caused by an excavation tool. An acoustic emission CAE) transducer was used to monitor the test samples as they were loaded. The signal from this instrument was recorded in real time along with the radial and axial loads generated by the fracturing device. Through the review of these signals on a common-time base, it was possible to see the relationship between the developing fracture and the loading conditions. As a part of the posttesting investigations, samples that were pletely fractured were sawn and ground to expose the fractures. examination of these samples allowed approximations to be made incom-Visual of the total surface created. Surface area approximations were also made for the completely fractured samples. Quantitative analyses· of the AE signals were conducted for comparisons with the calculated surface areas.

Jan 1, 1987

By Donald J. Ninteman

This Bureau of Mines publication is a literature study of the problem of spontaneous oxidation and combustion of sulfides in underground mines. It summarizes the present-day hazards, process mechanisms, and prevention and control techniques of this growing problem in underground mines. The iron sulfides generally have the greatest tendency to oxidize, particularly pyrrhotite. The presence of moisture and oxygen is essential for the oxidation reaction. Highly fractured sulfides, when found with timber or combustible refuse in slowly circulating air, pose the most serious fire hazard. Quenching with water is effective in quickly dealing with local hot spots, but ventilation at high flaw rates is the most effective and economical means for long-term prevention and control.

Jan 1, 1978

By Todd M. Ruff

Blind areas around construction equipment are a major contributing factor in incidents involving a piece of equipment striking a worker. In highway construction, these types of incidents result in an average of 22 deaths a year in the United States. The Spokane Research Laboratory of the National Institute for Occupational Safety and Health, in cooperation with the Washington State Department of Transportation, is evaluating methods to decrease these incidents. One such method uses devices that assist equipment operators in monitoring blind areas around the equipment to prevent collisions with workers or other objects. Several camera and sensor systems are available for this application. These systems were evaluated on various trucks used in road construction and maintenance. Tests were conducted on sanding trucks during the winter months, which allowed researchers to investigate the effectiveness and limitations of various technologies under the most extreme conditions. Tests were also conducted on dump trucks and utility vehicles during the warmer months to study the effectiveness of the systems in highway work zones. Results showed that many difficulties arise when using camera and sensor systems in cold, snowy climates. And, while the operation of these systems is more reliable during the warmer months, challenges still exist in using them on equipment in congested work areas.

By John R. Bartels

Remote operation of continuous mining machines has enhanced the health and safety of underground miners in many respects; however, numerous fatal and non-fatal continuous miner struck-by accidents have occurred. In an effort to prevent these injuries, NIOSH researchers at Pittsburgh Research Laboratory studied the workplace relationships between continuous miner operators and various tramming tasks of the equipment using motion capture data, operator response times, and field of view data to evaluate the factors influencing operator-machine struck-by events (contact with a solid object) in a virtual mine environment. It is not feasible (nor ethical) to use human subjects to directly evaluate factors that precipitate such injuries. However, use of motion analysis data and digital human models can facilitate analysis of struck-by accident risk by allowing investigators to manipulate factors that influence injury. Factors included in this study included machine speed, direction of escape, the direction the operator was facing relative to the machine, work posture, distance from machine, and operator anthropometry. Close proximity to the machine, high machine tramming speeds, a right-facing orientation and operator positioning near the tail all resulted in high risk of being struck.

Jan 1, 2008

By William L. Crentz

Early in the nineteenth century, coal from Clearfield County entered the eastern commercial market. Ashley reports that coal was moved down the Susquehanna River by ark from Clearfield to Columbia, a distance of 260 miles, as early as 18o4. Around 1850, the famous Moshannon or Lower Freeport bed was discovered. Several years later the Moshannon Basin was developed extensively, and the coal from this area soon acquired an enviable reputation as a high-quality industrial fuel. Today much of the original Moshannon Basin coal is worked out, and the Lower Kittanning bed has replaced the Lower Freeport bed as the principal source of production in southeast Clearfield County. With depletion of the thick underground deposits, the importance 'of Clearfield County as a coal Producer would have diminished rapidly, if it had not been for strip mining the thinner beds. About 60 percent of the coal produced in the county is strip-mined, and the trend toward this mining method is expected to continue as the older underground operations are exhausted. Many strip mines are working in beds that are too thin to be recovered economically by any other method.

Jan 1, 1952

By R. H. Grau, S. B. Robertson, J. Dolgos, T. P. Mucho

The National Institute for Occupational Safety and Health (NIOSH) has developed a computer program called the Air Quantity Estimator (AQE). The purpose of the program is to provide a starting point for estimating the air quantity needed to dilute diesel particulate matter (DPM) in an underground large opening mine, albeit taking into account various input assumptions. The AQE estimates the total air quantity needed to dilute DPM emissions that enter the main airstream of the mine to current statutory levels. It helps operators pinpoint vehicles that are high DPM contributors. In addition, it allows the user to make “what if” scenarios by varying the input parameters to achieve the most efficient and practical ventilation system. The AQE is a stand-alone software program that does not require any type of spreadsheet software. Engine data must be known or estimated with some accuracy and assumptions must be made in order to limit the variability of the program output. Program calculations and two case studies, for validation purposes, are included in this report. It should be noted that the program does not ensure adequate face ventilation and personal exposure compliance.

By John A. Kiefer

Ground fault and overcurrent protection criteria for coal mine a.c. distribution systems were examined under a Bureau of Mines funded investigation. The report begins with a literature review which discusses relaying topics including instrument transformers, ground-fault pickup methods, static relaying, and comparison of relaying techniques. A chapter on ground-fault relaying provides recommendations for maximum and minimum pickup levels as a function of maximum ground current and power system line-to-ground capacitance. Research in the area of phase overcurrent protection has resulted in a complete set of procedural recommendations for the selection and setting of overcurrent relays and current transformers, molded-case circuit breakers, and distribution system fuses in coal mine power systems. The final chapter, which discusses relay system maintenance, introduces a unique test set which was developed by KETRON and used to test the performance of relaying systems in coal mines.

Jan 1, 1980

By G. H. Bennett

A field experiment was performed in a production unit of an operating copper room and pillar mine to compare the support capabilities provided by resin and mechanical roof bolts. Resin and mechanical roof bolts were alternately installed in eight intersections in a single entry. Rock mechanics instrumentation was installed to measure roof sag, bed separation, convergence, bolt pullout, torque, and strain. Bolt cost and installation time are included. Two analyses of the test were made. The analysis of the rock mechanics data showed there was no definite difference between the two bolting systems. From a broader analysis on a mine-wide basis it was concluded that resin bolts gave better support. A critical view of the experiment is given in the appendix.

Jan 1, 1974

By W. E. Dennis, M. M. Fine

"INTRODUCTION During peacetime, the United States uses less than 3,000 tons of chemical-grade celestite annually. The war need, however, was estimated to exceed 15,000 tons a year.Hitherto; most of the required chemical-grade ore has been imported from England, Mexico, and other foreign countries. If foreign sources do not find it possible to meet the demand for ore of chemical grade (plus 92 percent SrSO4), it is expected that requirements could be satisfied by concentrating low-grade domestic ores. Celestite deposits on Brown, Nolan, Fisher, and Coke Counties, Texas, are considered to be possible sources of supply for this low-grade material. The Bureau of Mines explored the most important deposits to determine the grade and amount of ore available and conducted ore-dressing tests to obtain a suitable method of concentration.The exploratory work, consisting of test pitting and sampling, was carried on under the direction of W. E. Dennis, one of the authors of this paper, from October 8, 1942, to January 30, 1943. The ore dressing-tests described herein were conducted at the Bureau of Mines Laboratory at Rolla Mo.In this report, a particular deposit is referred to by the name of the landowner on whose .property the .deposit lies. The location of the deposits investigated is shown on figures 1, 2, 3, and 4.The celestite deposits were previously studied by the Bureau of Economic Geology of the University of Texas, and the results of its investigation are published in Mineral Survey Circular No. 46."

Feb 1, 1947

By Albert L. Toenges

The Grundy coal field is in process of development, and this circular was written to describe the mining methods and practices in use in the mines now being worked in this field. In lieu of man-hour labor data for individual mines a consolidated sheet of mine costs, which includes expenses for labor, material, and power, is given for all mines. The costs are for a working day only, based on average daily production. Because the demand for coal is seasonal, the costs for idle days, which vary at each mine, have not been estimated. Approximate reserves of coal seams have been estimated from data and maps taken from Bulletin XVIII of the Virginia Geological Survey4/.

Jan 1, 1936

By F. W. Smith

To determine whether preheating coals before carbonization would improve the coking properties of the coals, particularly the weaker coking coals, 3 coals, 1 each from Illinois, Kentucky, and Pennsylvania, and a blend of the Illinois with a Pocahontas coal were preheated before testing for coking properties in the Bureau's BM-AGA pilot oven. The effects of preheating on the chemical and physical proper-ties of the coals and on the yields of carbonization products and strength of the coke produced from the preheated coals were determined, as were also the effects of bulk density, gaseous atmosphere, and residence time during preheating. Most benefit from preheating was found with weaker or oxidized coking coals, whereas the more strongly coking coals and blends showed little effect. Direct charging of preheated coal to the coke oven without cooling gave better coke, increased yield of tar, and decreased yield of gas. INTRODUCTION Although 94 percent of today's coal production comes from fields east of the Mississippi, the Eastern States have only about one-third of the Nation's recoverable reserves. West Virginia, which now produces more than any other State, has much smaller reserves than Utah, Colorado, and Wyoming.5/ However, the manufacture of iron and steel in Western States, which has increased greatly since World War I, is handicapped by the scarcity of high-grade coking coals, such as are plentiful in the Appalachian region. Unless a practical method of improving the cokemaking property of local coals is developed, ferrous metallurgical industries in the West must continue to use inferior coking coals and to pay high shipping charges for better coals.

Jan 1, 1958