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By Forrest T. Moyer

THE injury data and experience in this bulletin are presented in three general sections. The first section contains general and detailed data relating to 1948 injury experience in bituminous-coal and Pennsylvania anthracite mines, separately and combined into totals for all coal mines. The related employment, worktime, production, and productivity data are given in each breakdown of the statistical data. Tables 1 through 22 constitute a subsection and present statistics on number of injuries, frequency and severity rates, average severity, detailed and major causes of injuries, injury records of the coal-producing States, distribution of injuries by part of body, and distribution of injuries by days of disability. Tables 23 through 45, the second subsection, present injury experience in bituminous-coal mines by various selected factors of physical or operating conditions that ma contribute to the occurrence of injuries. The degree of mechanical loading, productivity, size of mine by number of men working and by tonnage mined, thickness of bed, length of shift, number of shifts, type of cap lamps, rating of mine as gassy or nongassy, type of ventilation, and combinations of these factors influencing mine safety are presented in this group of tables. Similar data on Pennsylvania anthracite mines are listed in tables 46 through 63, which comprise the third subsection. The second section of the report contains the generalized annual injury records of bituminous-coal, Pennsylvania anthracite, and all coal mines from the earliest available data through 1948. Tables 64 through 97 list the number of fatal and nonfatal injuries, injury rates, and causes of injuries on an industry basis, the long-term injury records of each coal-producing State, and the related employment, worktime, and production data.

Jan 1, 1952

By Vernon C. Davis

In initial attempts to mine taconite by conventional open-pit methods, the material tended to break into tabular blocks that were too large to be handled by conventional shovel dippers and were unsatisfactory in an ordinary crusher feed. A great amount of secondary blasting was necessary, which added considerably to the cost of mining. The Bureau of Mines and others are engaged in studies designed to contribute to the solution of taconite-mining problems. These studies concern problems related to drilling techniques and patterns, types and methods of use of explosives, and other factors relative to effecting maximum fragmentation at minimum cost. This report, is concerned with study of the application of shaped charges in drill holes, the effectiveness of shaped charges as compared to capped charges in secondary blasting, and the merits of different drilling patterns and methods of detonation of conventional-explosive charges. Fragmentation of taconite at or near the surface is controlled or strongly influenced by joint and bedding planes. Since all tests in this study were made in a jointed and bedded area, a definite conclusion as to the relative effect of a shaped charge in a drill hole, as compared to a conventional charge at greater depths and tighter ground, is precluded. However, application of shaped charges in primary blasting of taconite appears to be of no advantage. In secondary blasting of taconite, conventional, capped charges produced better breakage than shaped charges of the designs tested. Based on the results of conventional blasting practice in horizontal-, inclined-, and vertical-hole tests, no better fragmentation is obtained from blasting either horizontal or inclined holes, compared to vertical holes. Holes drilled in staggered parallel rows that intersect both series of joint planes at the greatest possible angle, give maximum breakage compared to rows paral-lel to one of the series of joint planes. Methods of detonation made little difference in breakage; but the milli-delay caps produced the best conditions for moving the broken rocks.

Jan 1, 1953

By George S. Rice

In response to numerous requests for information as to the status of internal-combustion mine locomotives of the Diesel type that use heavy or non- volatile oil for fuel, with special reference to their safe use in coal mines, the United States Bureau of Mines is issuing this report. Data mere obtained, on application of such locomotives to cod mining only in Belgium, France, Germany, and Great Britain. The locomotives are used in coal mining in other countries, as well as in potash, iron, and other kinds of mining, but their chief development has been in coal mining in Germany, France, and Belgium. Recently popular interest in the Diesel type of engine for motive purposes was aroused in this country by the successful application of Diesel engines to railroad locomotives hauling fast transcontinental trains, and, according to published statements, at a low cost of fuel per mile of run.

Jan 1, 1936

By Linneas Laage, Thomas Weber, William Pomroy

"Underground mine fires can significantly influence mine ventilation airstreams, in some cases throttling or even reversing airflows. As a result, the performance of a metal and nonmetal mine stench fire warning system, which depends on the ventilation to carry the vital warning signal, under fire conditions is different from performance under nonfire conditions. The safety of underground miners can be jeopardized if the warning signal is delayed. This Bureau of Mines report describes research to investigate fire and stench warning system interactions. A computer model is presented that permits quantitative analysis of stench warning signal delays as a function of fire location and intensity. The results of a case study involving computer simulations of stench distribution in a hypothetical mine network subject to various fire exposures are also discussed. This case study illustrates a technique for identifying the areas within a mine that are subject to unacceptable warning signal delays, thereby enabling preemptive action by mine personnel, such as redeployment of stench injectors. INTRODUCTIONFires are an ever-present threat to the safety of underground miners. Since the smoke and toxic gas produced by a mine fire can be spread rapidly by the mine's ventilation system, mine evacuation must be accomplished as quickly as possible in the event of fire. In metal and nonmetal mines, the most common means of passing the fire warning signal to each miner is the stench system. The typical stench system utilizes ethyl mercaptan, a highly odoriferous organic compound, injected on the surface into the compressed and/or ventilation airstreams. Upon smelling the stench, workers evacuate the mine according to an emergency preplan.Although the stench system has been used successfully for over 60 yr, it has several serious shortcomings, owing to certain chemical properties of ethyl mercaptan and to certain performance characteristics and limitations of present injection systems.Recent Bureau research succeeded in upgrading the overall safety and effectiveness of the stench system through the use of a superior stench odorant and the development of improved stench injection equipment (1).4 This research has also investigated a specialized computer simulation model capable of calculating the precise concentration of stench in any mine ventilation network branch at any time after stench release (2). An adaptation of the computer model now enables the analysis of stench system and ventilation system interactions under the influence of a mine fire."

Jan 1, 1987

By R. A. Franks, G. F. Friel, J. C. Edwards, L. Yuan

Two mine-fire experiments were conducted in the National Institute for Occupational Safety and Health's (NIOSH) Safety Research Coal Mine (SRCM) at the Pittsburgh Research Laboratory (PRL) which demonstrated that smoke from diesel-fuel fires of 500 kW and 660 kW heat-release rates in a return airway can develop, without causing a complete air flow reversal, into a roof layer that can migrate upwind forming a counter flow to the primary airflow in a crosscut. Subsequently, smoke can penetrate into an intake airway and create a hazardous atmosphere in the intake airway upwind from the fire. Visibility conditions less than 13 m were created by the smoke in the intake airway downwind from the crosscut. Modeling of the event with a three-dimensional, time-dependent, computational fluid dynamics (CFD) program correctly represented the smoke movement.

By Pamplinm J. W.

"INTRODUCTION For the past six years the United States Bureau of Mines in cooperation with the University of Alabama, Tuscaloosa, Ala., the Missouri School of Mines and Metallurgy, Rolla, Mo., and certain operating companies of the Florida land-pebble phosphate district have conducted an investigation to determine the amenability of phosphatic sands to concentration. 4 This paper discusses briefly an investigation of the concentration of fine phosphatic sanads of the land-pebble district of Florida. The process used - namely, the tabling of material previously given a selective oiling treatment - is new in its application to the phosphate industry, although old in principle.The feed to the standard phospidate washery is a hydraulically wined mixture of phosphate pebbles, quartz sand, and clay in which the quartz sand grains are segregated in the fine sizes. Me standard method of concentrating (washing) consists of wet-screening. at about 20 mesh to recover the plus 20-mesh material. 5 Lately some of the washeries have introduced hydraulic classifiers for sizing of the screen undersize to recover the coarser spigot products, but even this additional treatment allows much of the fine phosphate to be wasted."

Dec 1, 1932

By George S. Rice

In response to numerous requests for information as to the status of internal-combustion mine locomotives of the Diesel type that use heavy or nonvolatile oil for fuel, with special reference to their safe use in coal mines, the United States Bureau of Mines is issuing this t port. Data were obtained on application of such locomotives to coal mining only in Belgium, France, Germany, and Great Britain. The locomotives are used in coal mining in other countries, as well as in potash, iron, and other kinds of mining, but their chief development has been in coal mining in Germany, France, and Belgium. Recently popular interest in the Diesel type of engine for motive purposes was aroused in this country by the successful application of Diesel engines to railroad locomotives hauling fast transcontinental trains, and, according to published statements, at a low cost of fuel per mile of run.

Jan 1, 1936

This Bureau of Hines report on underground mine communications addresses methods and equipment to meet the communication requirements of working sections and places of coal and metal-nonmetal mines. A review of the status of trapped miner detection is also presented.

Jan 1, 1977

By Stephen C. Tadolini

The U.S. Bureau of Mines has developed ultrasonic measurement instrumentation capable of measuring strains and elongations on tensioned and untensioned mine roof bolting systems. This report evaluates the pulsed-phase-lock-loop and pulse-echo systems. The pulse-echo systems measure time of flight of a signal through the bolt. The ultrasonic instrument converts the measurement into elongations or stress. The most recent Bureau instrument development converts travel-time measurements directly into elongation, load, stress, and torque by simple data manipulation from the keyboard. Bolt preparation and instrument calibration are described in detail.

Jan 1, 1990

By Pedro Lilienfeld

This report describes a program whose objective was to develop, design, fabricate and laboratory-test two prototype instruments capable of real-time selective detection and measurement of airborne fibrous-shaped particles. The operation of this fibrous aerosol monitor (FAM) is based on the rotation imparted to the acicular particles by means of a rotating quadrupole electric field of the order of 3000 V/cm. This field induces a dipole charge separation on the fibers and aligns them with the applied field. The selective detection of the fibers is effected by synchronous detection of the resulting modulation of the light scattered from a continuous-wave helium-neon laser beam by the rotating particles. The theory of operation, design of the electric-optical detection configuration and the electronic signal processing method are discussed. By means of a scattering pulse sharpness discrimination technique, fibers whose length exceed a selectable value are detected and their number concentration digitally displayed. Counting times of 1 to 1000 minutes permit the measurement of fiber concentrations between 0.001 and about 30 cm-3. A concentration of the order of one fiber per cubic centimeter can be assessed within a relative standard deviation of 10 percent with a counting period of 10 minutes. The FAM is a portable, battery-powered instrument capable of operating continuously for about 4 hours between battery charges. Preliminary tests with crocidolite and crysotile asbestos as well as with glass fibers were performed in the laboratory and the results indicate good correlation with the standard NIOSH phase contrast microscopy filter counting method.

Jan 1, 1977

By Jon C. Volkwein

The U.S. Bureau of Mines conducted a study to assess the impact of a directional water spray system on a unique single inlet dust scrubber on a low-profile mining machine. Tests were conducted in a full-scale model mine using a continuous mining machine. Tracer gas was introduced at the face and concentrations of the tracer gas were monitored at the face and in the return. Various parameters tested included mining position, depth of cut, brattice setback, and combinations of scrubber, and directional or symmetrical sprays. Results indicated that either water spray configuration improved the ventilation effectiveness of the scrubber by a factor of 2 to 3. Average face ventilation effectiveness (FVE) values for all testing of the scrubber and directional sprays were 0.95, versus 0.37 for a standard 20-ft blowing curtain without sprays. No FVE values were less than the standard 20-ft blowing results.

Jan 1, 1989

As part of the overall development of a borehole mining system -develop backfilling techniques to reduce possible damage to the environment caused by either the cavities or the piles of sand tailings that result from in-borehole hydraulic mining. (Borehole mining is described in technology News No. 56.) Approach Water filled cavities at the bottom of boreholes are rapidly and economically backfilled by jetting a sand-tailings slurry underwater. How It Works The Bureau of Mines borehole mining system creates a cavity having a horizontal diameter of more than 50 feet. (See photograph). This cavity can be backfilled with much of the sand previously mined. The sand tailings or similar backfill material is dumped by a front end loader into a slurry mixing tank at the rate of about one ton every three minutes. Enough water is added to give a thick, but pumpable slurry. The slurry is pumped down the borehole through a string of 4-inch pipe to the cavity. After passing through a right elbow at the end of the pipe, the slurry is ejected through a nozzle. The resulting slurry jet emplaces the backfill at the outer wall of the cavity. To obtain an even distribution of fill in the cavity, the nozzle is slowly rotated. The nozzle and pipe assembly is supported from a turntable on the surface. See diagram.

Jan 1, 1981

By William A. Beck

This paper is one of a series, describing current practice in diamond drilling for production at various mines throughout the United States. It describes the drilling and blasting methods, used at the Tennessee Copper Co., which started using deep-hole drilling for blasting in 1927, employing inde- pendent, rotation percussion drills with sectional drill steel. Since 1942 the company has employed diamond drills for deep-hole drilling. This method has now passed the experimental stage and promises to become permanent. The elimination of rock dust and safer working conditions for the drill crews are listed as the main advantages. The higher initial cost of equip- ment is the principal disadvantage.

May 1, 1948

By H. D. Kline

This publication describes mining and milling methods and costs at the Madison mine of National Lead Co., St. Louis Smelting & Refining Division, in the Fredericktown district of southeast Missouri and is one of a series prepared by the Federal Bureau of Mines on methods, practices, and costs of mining and milling throughout the United States. The are bodies of the Madison mine are known for the complexity and diversity of their are minerals. Sulfides of copper, nickel, and cobalt occur in commercial quantities with lead sulfide, which is the most valuable metallic mineral in are bodies of the Bonne Terre formation in southeast Missouri. Several attempts were made by various operators to mine the complex ores and separate the sulfide minerals before 1927 when National Lead Co. became interested in the Fredericktown district. Operating then as the St. Louis Smelting & Refining Co., the company began mining and milling ores from the Madison mine in 1944 and has operated continuously since then. A recently built refinery produces copper, nickel, and cobalt metal from a concentrate containing iron sulphides and small quantities of copper, nickel, and cobalt sulphides.

Jan 1, 1961

By E. C. Lane

"INTRODUCTION The first important discovery of petroleum in New Mexico was near Dayton, Eddy County, where the Brown well was drilled in 1909, and small quantities of oil were produced. In 1911 and 1912 wells were drilled in McKinley County, but commercial production did not begin until the discovery of the Hogback field, San Juan County, in 1922. The discovery well in the Artesia field, Eddy County, drilled in 1923, gave impetus to active drilling in many areas. Since 1924 New Mexico has produced petroleum in commercial quantities and since 1930 the State has joined the ranks of the big produc¬ing States, being sixth or seventh in total production in recent years.Production by years. 1924 to 1940, inclusive, taken from annual figures in Bureau of Mines Minerals Yearbook, are given in table 1. The total production shown is 274,331,000 barrels. Andreas 3/ has published production figures for the year 1940 and a resume of all production to the end of 1940. Data from his report are presented in table 2 for each field sampled. The cumulative production, as given by Andreas, is 270,618,575 barrels."

Aug 1, 1942

By Margaret R. Egan

A series of experiments were undertaken by the Bureau of Mines to determine the emission products of several types of conveyor belting and other combustible materials found in mines. These experiments were conducted under intermediate-scale, simulated mine conditions to determine smoke characteristics and gas concentrations. From these determinations, heat-release rates, particle sizes, obscuration rates, combustion yields, and production constants were calculated. Three types of belts were investigated: chloroprene, also known as neoprene (NP); polyvinyl chloride (PVC); and styrene-butadiene rubber (SBR). The belts were designated as ignitable or self-extinguishing depending on the length of the burning time and the subsequent combustion products. Under these experimental conditions, the SBR belts were the easiest to ignite. The PVC and NP belts tended to self- extinguish within a few minutes after ignition, but were still capable of maintaining a brief flaming period. These conveyor belt combustion results are compared with previous analyses of wood, transformer fluid, and coal fires. Together they form a data base by which findings from future experiments with other mine combustibles can be compared.

Jan 1, 1988

By Edward W. Ames

"The Jewell tunnel property, situated 3/miles north of Garfield, Chaffee County, Colo., was examined by an engineer3 of the Bureau of Mines in June 1943. Field work began September 16, 1944, but was recessed from December 26, 1944, to gay 15, 1945, because of heavy snows, and was suspended July 12, 1945, when rehabilitation of the New York tunnel workings was completed to the point desired.In its program of exploration of Mineral deposits, the Bureau of Lines has as its promary objective the more effective utilization of our mineral resources, to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as seen .as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples of ore and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.For their supervision of the project and their help in revising the report, particular acknowledgment is due Wm. P. Huleatt, district engineer, Denver, Colo., and Paul T. Allsman, chief, Salt Lake City Division, Mining Branch.The property is situated in secs. 15 and 22, T. 40 N., R. 6 E., N.R.F.M. Salida, the county seat, is on the main line of the Denver & Rio Grande Western Railroad. The property is reached from Salida by following U. S. Highway 50 westward for 18 miles to the village of Garfield, near Monarch Pass, then northward for 3 miles by a very steep mine-access road up Taylor Gulch (fig. 1).The highway to Garfield is accessible throughout the year, but the access road from Garfield is generally impassable from December until June because of snow."

Sep 1, 1946

By Alvin Kaufman

Increased exploration in Alaska has resulted in many requests to the Bureau of Mines for facts about the mineral resources and mining conditions in the Territory. This report presents information about the minerals of Southeastern Alaska and the factors that affect development of a mining industry in that area. Southeastern Alaska is a narrow coastal strip of rugged mountains and many islands. The climate is mild, with an average annual temperature of 40° and heavy rainfall. Geologically, the region is favorable for deposition of ore; geographic-ally, it is difficult to prospect and to develop, except along areas immediately adjacent to the coastline.

Jan 1, 1958

By H. R. Shell

Fluorphlogopite mica was synthesized from inexpensive and abundant olivine, clay, feldspar, and sand (plus K2SiF6). The raw materials were melted in crucibles and in an internal resistance electric furnace. The melts yielded >95 percent mica. The major difficulty encountered was incomplete settling of the highly dispersed ferroalloy. This problem was not completely solved. Reducing agents tried in melts of 300 to 400 pounds were carbon, silicon, and silicon carbide. Carbon slowly reduced the iron of the raw materials, with much fuming. Silicon apparently was oxidized ahead of the melting and was ineffective under the conditions obtained. By far the best reducing agent was silicon carbide. With silicon carbide, fuming did not occur and ionic iron content of the mica flake approached 0 percent. However, even with SiC, the highly dispersed globular iron did not completely separate from the mica portion. The fluorphlogopite made during this investigation should be suitable for metallurgical use. A byproduct ferroalloy containing about 5 percent nickel, 3 to 5 percent chromium, and some cobalt was obtained. Because of the highly dispersed metallic ferroalloy, the mica was not deemed suitable for electrical or electronic uses.

Jan 1, 1962

By J. A. Cooper

The objectives of this research were to define the chemical composition and physical characteristics of the aerosols associated with attached radon daughters in operating uranium mines, and to investigate the relationship between these aerosol parameters and operating conditions. Major Results and Conclusions The organic, inorganic and radiological characteristics of test chamber and active U-mine aerosols have been measured as a function of particle size. These measurements represent the first detailed analyses of the organic and inorganic components in U-mine aerosols and the first determinations of the details of the individual and total radon daughter distributions in operating U-mines. The following is a list of the major results and conclusions:

Jan 1, 2012