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By Daniel Harrington

For several years the United States Bureau of Mines has been making a study of ventilation in metal mines, this study covering practically all the important mining districts of the country. One of the districts where a close and extended study was made was that of Butte, Mont., with its numerous interesting problems and conditions. In February, 1916, Daniel Harrington, mining engineer of the United States Bureau of Mines, was detailed to investigate the circumstances surrounding the death of 21 men in the fire at the Pennsylvania mine at Butte, and during that investigation he made underground visits to several of the large mines through the courtesy of the mine operators, and became much interested in the ventilation conditions. In May, 1916, Mr. Harrington was detailed te work in cooperation with Dr. A. J. Lanza of the United States Public Health Service in an investigation of the prevalence and causes of miners' consumption in the district. This work broadened so much that the investigation was not completed until late in 1918, the investigators making a detailed inspection of all working places in four large mines and a more or less extended examination of conditions in about 20 other mines. Ventilation was recognized immediately as being an important factor in the health of miners, and from the outset of the investigation a large part of the work consisted in obtaining and compiling data relative to the flow of air, humidity, and temperature. The officialsof the North Butte mine were engaged in making a study of ventilation problems before the coming of the investigators, so that opportunity was given to work with those officials for several months. Detailed data on air flow, temperatures, humidities, and an analyses had been obtained before the fire in the North Butte mine June 8, 1917, which resulted in the loss of 163 lives. Much information was obtained during the progress of the fire, and a detailed examination was conducted after the fire, hence an exceptional opportunity existed to study conditions relating to ventilation. This bulletin is a result of studies made from the data collected during the two and one-half years of study and observation a-boveoutlined. Its publication has been delayed through lack of funds for printing. Other publications relative to metal mine ventilation -in other parts of the United States are expected to follow.

Jan 1, 1923

By M. Hertzberg

The Bureau of Mines measured the energy requirements for the spark ig-nition in air of Pittsburgh seam bituminous coal dust, lycopodium spores, and polyethylene powder with a 1.2-L furnace and 8-L and 20-L chambers. Thermal autoignition temperatures of the same dusts were mea-sured in the 1.2-L furnace. Electrical ignition requirements are given in terms of both effective spark gap energies, [ ] and stored circuit energies, 1/2 CE2. The measured order of electrical ignitability for the three dusts is consistent with the data of other researchers; however, the absolute values are systematically higher, probably because of higher flow and turbulence levels in the chambers used and lower electrical efficiency in the circuit used here. The temperature dependence of the lean limit of flammability for lyco-podium was measured wi th the 1.2-L sys tem, and those measurements con--firm the applicability of the modified Burgess-Wheeler law to a dust. Due to experimental complexities, the minimum ignition energies for dusts may not reflect intrinsic flammability behavior. However, some valuable information may be obtained from the relative ignition energies of various dusts at ambient and elevated temperatures. In addition, the concept of minimum electrical ignition energies for homogeneous gas mixtures is reevaluated theoretically.

Jan 1, 1985

By Edward E. Johnson

The U.S. economy made significant progress in 1984. The current-dollar gross national product (GNP), the market value of the Nation's output of goods and services, increased almost 11 percent over that of 1983 to slightly more than $3.66 trillion (table 1), and the real gross national product increased almost 7 percent.2/ Such rapid growth in real GNP has not occurred since the early 1950's. Real final sales increased only 5 percent during 1984, and real business inventories increased $24.8 billion ($57.9 billion in current dollars). Total employment of 106.7 million was an all-time record, and the unemployment rate declined from 9.5 percent in 1983 to 7.4 percent in 1984. During 1984 the U.S. dollar showed great strength on international markets, contributing to large current-dollar negative net exports of goods and services (-$62.5 billion) and even larger negative net exports of merchandise (-$107.6 billion). The strong dollar and the substantial increase in net imports of goods and services helped reduce U.S. inflationary pressures and provided a major source of loanable funds for financing domestic private investment.

Jan 1, 1985

By E. P. Youngman

The mining law of British North Borneo is entitled " The Mining Ordinance , 1927. 113 The only mining regulation or rule available is " Rules 313 , 114 passed in accordance with article 26 of the ordinance of 1927. Before the passage of this legislation , the country had no specific law governing the granting of mineral rights , although the land law contained provisions relating to mining lands . The land ordinance of 19135 still controls in a few details . All references in this paper , unless otherwise specifically designated , are to the mining ordinance .

Mar 1, 1933

By D. S. Kingery

Efficient transportation is necessary to complement modern mechanized mining methods. The increasing trend toward high-capacity face loading equipment has demanded equally efficient haulage methods; this has been met by increasing mine-car sizes, using larger locomotives, and increasing haulage speeds, all requiring properly installed and maintained haulage roads specifically designed for this type of traffic. The recommendations and specifications included in this circular were made to point out salient factors important to the proper construction and maintenance of track haulage roads and to serve as recommended standards for track installation and maintenance. GLOSSARY OF TERMS USED Haulageway. - The track, walkway, trolley wire, feeder lines signal end telephone lines, signals, telephones, support, and drainage of the entry referred to. Subgrede. - The base upon which the ballast is laid.

Jan 1, 1954

Capture airborne respirable dust generated by an auger-type continuous mining machine to reduce workers' dust exposure. Approach Install a water-powered scrubber system, operating at 1,400 psi, on the sides of the conveyor. The scrubber draws the dusty air from the face area and discharges cleaned air into the face return. How It Works Auger-type continuous miners pose unique ventilation and dust control problems. To protect face workers from the dust, the end of the brattice is usually maintained close to the face to increase ventilation effectiveness. However, it is taken down as the machine cuts toward the exhaust side to allow the machine to complete its cut. Often, the brattice is not reinstalled in a position to most effectively control

Jan 1, 1989

By King K. Mak

The objectives of this study are to: (1) Assess current signing regulations and practices; (2) Develop effective signing guidelines; and (3) Evaluate the applicability and appropriateness of the proposed signing guidelines through field demonstration at representative mines. A literature search was conducted to determine the state of the art for signing applicable to surface mine haulage roads as well as survey of existing MHSA regulations and review of MSHA accident records. Nine representative mines were visited to gather information on current signing practices. Preliminary signing guidelines were then developed based on the abovementioned data. Field demonstration of the preliminary signing guidelines was conducted in which signing programs were implemented in two selected mines. Signing requirements were first assessed at each of the two participating mines. Subsequently, the necessary signs were designed, purchased, and installed at the two mines. Evaluation of the signing program as to its adequacy, appropriateness, and effectiveness was solicited from both mine management and operations personnel. Experiences gained from field evaluation were then incorporated into the final signing guidelines as presented in this final report.

Jan 1, 1981

By Koehler Stout

Previous work done by the authors of this report indicates that hydraulically-placed backfill can be strengthened several fold by various placement methods. Sunshine mill tailings were tested by these placement methods and strength increases up to thirty times were achieved over the ordinary placement methods. A computer simulation study of the test stope in the Sunshine Mine showed that a high-modulus fill absorbs up to 27% of normal stresses versus 7% for "normal" fill while reducing maximum convergence 28% versus 8% for "normal" fill. Although high-modulus fill was not placed in the test stope during this contract, various instrumentation was purchased, designed and built to record necessary data in the stope. Stress gauges were placed in the pillars and recorded data corresponded quite closely with theoretical projections.

Jan 1, 1983

By D. Harrington

As no cure is known for silicocis after it has developed, prevention is the only effective remedy. There are two main lines of approach to the problem of dust-disease prevention in industry - the engineering, through control of dust production, and the medical, through selection of workers by examination; success probably depends upon a combination of the two. Hatch (146) considers the following measures essential to a complete, well-balanced program of control of the dust hazard in industry: 1. Selection of workers by means of physical examinations in order especially to eliminate those with tuberculosis and other disorders of the respiratory system. 2. Reduction of the duct concentration below the standard of permissible dustiness through adequate moans of dust control and good housekeeping. 3. Limiting the frequency and duration of employment in the dusty occupations, thus reducing the rate of deposition of dust in the lungs. 4. Routine measurement of the effectiveness of the dust-control program by means of periodic medical examinations and duct surveys.

Jan 1, 1935

By Fredrick L. Johnson

The Bureau of Mines, under Congressional mandate, conducted a mineral survey on the Park Range WSA (Wilderness Study Area) in 1984 and 1985. The WSA, located about midway between Tonopah and Ely, encompasses 47,268 acres. No mineral resources were delineated, nor were workings found, during the investigation. There has been, however, exploration in and near the north end of the study area. ASARCO is actively exploring a block of 41 claims for hot-spring type, low-grade, large-tonnage gold deposits. Their claim block is almost entirely in the study area. The Morey mining district, 7 miles southwest of the study area, produced silver and lesser amounts of gold and lead sporadically from the mid-1860's through the mid-1960's. The WSA is underlain by Tertiary rhyolitic and latitic volcanic rocks and by Paleozoic sedimentary rocks. The Paleozoic rocks have been faulted, silicified, brecciated, and hydrothermally altered, and have anomalous concentrations of precious metals and pathfinder elements. Additional exploration in the north part of the Park Range WSA may lead to delineation of gold resources.

Jan 1, 1986

By Bernard Lewis

During the past 10 years the technical investigations conducted by the Explosives Division of the Mine and Explosives Bureau of the Bureau of Mines have been described in a series of summarizing reports prepared by Wilbur I. Huff, consulting explosives chemist of the Bureau. These reports covered the…

Dec 1, 1947

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

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, improve or modify coal mine fire-fighting strategies and methodologies through large-scale tests. Since wood is the second most abundant fuel available during a coal mine fire, it was decided that series of large-scale wood crib fire tests were 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.

By D. K. Denton, J. M. Girard, D. F. Scott, T. J. Williams

Personnel from the Spokane Research Laboratory, National Institute for Occupational Safety and Health, examined an underground pillar at the Homestake Mine, Lead, SD. Investigations involved strain relief and seismic tomography studies in the mine, and ultrasonic velocity measurements on pillar core in the laboratory. Measured octahedral normal stress was 37 MPa (5,366 psi); seismic P-wave velocities averaged 5.2 km/s (17,060 ft/s); and ultrasonic velocities at a pressure of 39.6 MPa (5,750 psi) averaged 6.3 km/s (20,669 ft/s). The difference between in-mine and laboratory velocities is attributed to the attenuation of seismic energy by mine fractures larger and more numerous than those in the samples of core measured in the laboratory. Using these results, researchers hypothesize that pillar rocks have the ability to withstand stress an order of magnitude greater than they currently sustain.

Duty on Lead Reduced. -On December 28, the President signed H.R. 5047 which reduces the duty on unwrought lead from 3.5% ad valorem to 3% ad valorem, with a floor level of 1.0625 cents per pound, effective retroactively from January 1, 1980, through June 30, 1983. Pacific Northwest Power Bill Passed. -On December 5, the President signed S. 885 which will enable the Bonneville Power Administration to guarantee 20-year contracts to its 15 major industrial customers in exchange for higher rates. In effect, the bill will have industrial customers pay some of the costs of building additional generating facilities in the Northwest, of which thermal units are expected to be a major part. BPA supplies power to six primary aluminum producers which operate eleven plants having over 30% of the primary aluminum capacity in the United States.

Jan 1, 1980

By William Hustrulid

The National Institute for Occupational Safety and Health (NIOSH), as part of a comprehensive program to improve mine safety through the widespread acceptance of careful excavation principles in drifting, have revisited standard drift round design concepts. Although the initial emphasis was on contour row design and providing improved design tools for blasting with de-coupled charges, the focus has broadened into the development of a general gas pressure-based drift round design approach. The concept of a damage radius (Rd) for a given explosive-hole-rock mass combination is introduced. With the damage radius as the basic building block, the blast holes are positioned on the face, beginning with the buffer row, to achieve the desired excavation size, shape and smoothness. The design of the contour row of holes is also performed using a pressure-based approach. The paper presents in some detail the overall approach and the required gas pressure-based design equations.

Jan 1, 2007

By Walter W. Fisher

A study of copper cementation on iron was initiated to determine the effect that deposited copper has upon subsequent cementation. A microscopic investigation of cementation on an iron surface showed that cupric ion precipitates predominately on a growing copper deposit attached to the iron surface. A kinetic study of the cementation process in a revolving drum showed that the cementation rate is enhanced by the copper deposit attached to the iron surface and by the discrete copper particles of a cement copper slurry. The kinetic study also indicated that the character of the deposit is affected by the major anion in the solution. The cementation process is visualized to occur as a series of electrochemical cells in which cupric ion precipitates on copper dendrites attached to the iron surface.

Jan 1, 1973

Objective To develop safety training tools for mine safety and health professionals that fill gaps in currently available materials. Background Over the past 4 years, NIOSH has developed and released a series of training videos targeted at underground mine safety. These videos were developed in close cooperation with the mining industry and safety training professionals and were intended to provide realistic, interesting, effective training to both new hires and experienced miners. The videos cover the mining cycle, starting with the breaking of the rock (Handling Explosives in Modern Mines), making certain the work area is safe after a blast (Rock Falls— Preventing Rock Fall Injuries in Underground Mines), installation of ground supports and recognition of failed supports (Miner Mike Saves the Day), and hauling both ore and materials in the mine (Hazards in Motion). A separate video (Hidden Scars) captures the story of a fatal rock burst through an interview with a miner who nearly died and who lost his partner in the accident. These videos have been extremely popular in the mining industry and are being used across the nation as well as in 18 other countries. Two of them, Rock Falls and Miner Mike Saves the Day, have won Alice Hamilton awards, NIOSH’s highest recognition for Excellence in Occupational Safety and Health, in the Educational Materials category. Approach A recently completed independent evaluation of the SRL mining videos identified five themes that mine safety trainers consider necessary for successful training materials: high quality, credibility, accurate content, effectiveness, and an engaging nature. All of the NIOSH videos were rated very high for each theme. Using these measures of effectiveness, a more difficult challenge has been undertaken. Much has been written in the mining industry about the coming turnover in employment. The average age of miners in the United States is approaching 50, and many of the “experts” will be leaving the industry as they reach retirement age. The mining industry, like many industries involving skilled labor, relies heavily on a master-apprentice relationship between new hires and older miners. New hands learn from experienced miners. Their learning falls into three primary categories—they learn what’s important to know, they learn how to do things correctly and safely, and they learn the culture.

Mar 1, 2002

By Linneas W. Laage

The purpose of this report is to document the fire experiments conducted at the Waldo Mine, NM during March 1990. The U.S. Bureau of Mines is concerned with improving and validating the predictive capability of the mine ventilation and fire simulator, MFJRE. To accomplish this, fire experiments were conducted at the Waldo Mine and temperature profiles were developed as functions of time and distance from the fire. These tests then provided data for verifying the heat transfer model in the MFIRE mine ventilation and fire simulator. An initial analysis of this data indicates that it will serve this purpose well. This report summarizes the data obtained during six fire tests at the Waldo Mine.

Jan 1, 1994

By J. H. Stears

Increasing use of Birmingham and other roof trusses prompted a Bureau of Mines study of support forces produced on a mine roof by these members. Equations, obtained from laboratory and field tests, are given for calculating the contact forces between the roof strata and a typical truss. Actual contact forces for a specific truss are difficult to estimate because of variable friction loss at the contact points. A finite-element analysis, using typical contact forces, indicated that trusses have a negligible effect on the stress field in massive, competent roof strata. The effectiveness of trusses in supporting broken rock strata was not analyzed. However, experience has shown that trusses are effective in supporting incompetent roof.

Jan 1, 1988

By Terry J. Close

In 1986 and 1987, at the request of the U.S. Bureau of Land Management, U.S. Bureau of Mines personnel studied 7,040 acres of the 7,240-acre Sheep Mountain Wilderness Study Area (OR-006-003) in order to evaluate its identified mineral resources. The area studied is along the divide between the Snake River and Pine Creek about 1.5 mi south of the village of Oxbow in Baker County, OR. No mineral resources or mineral-related activities were identified in the Sheep Mountain study area. The basalt covering most of the study area has no known mineralized sites. However, it contains common agate and opal that is of limited interest to mineral collectors. This basalt (stone) could be used locally as construction material (crushed stone or fill); however, suitable material is wide spread in the region and more accessible to possible markets.

Jan 1, 1987