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By Donald F. Reed

In its program of investigation of deposits of strategic minerals, the Bureau of Mines did some development drilling from October 1247 to March 1948 at the Pickering Creek deposits, Charter County, Pa., in an endeavor to find an additional source of supply of lead and zinc. Lead mining in Pickering Creek Valley showed great activity from 1851 to 1855; but after this period mining gradually declined until 1870 when all mines were. One small mine did some work from 1917 to 1920. The ores were sulfides of lead and zinc, which were partly oxidized from the surface to the 20-foot level. As zinc was penalized at the reduction works, the ore was sorted at the mine and the zinc discarded. The Wheatley and Chester County veins contained the beet ore bodies in the district. These converging veins are 2 to 5 feet wide. To cut the veins below the old mine working' the Bureau of Mines diamond-drilled eight holes aggregating 2,820 feet. No significant lead-zinc mineralization was found.

Jan 1, 1949

By D. W. Frommer

Processing of nonmagnetic taconites by selective flocculation-des liming and anionic flotation of calcium-activated silica has been investigated using innovative procedures as a means of improving operating costs. Areas chosen for cost-cutting evaluation were grinding, fine screening, and water conservation and reclamation. The investigation was performed on Marquette range nonmagnetic taconites in the Bureau of Mines Twin Cities Metallurgy Research Center flotation pilot plant, at feed rates ranging between 900 and 1,100 lb/hr. With fully integrated water reclamation, flotation concentrates containing 65.8 percent Fe and 3.4 percent Si02 were made in the best operating period, with accompanying weight and iron recoveries of 40 and 74 percent, respectively. During this same period, the estimated cost of both flotation and water reclamation reagents was only $0.80 per ton of concentrate (1968 pricing basis). This cost is about 15 percent lower than obtained previously at this Center for flotation reagents only. The investigation demonstrated additional potential savings in operating costs of approximately $0.96 per ton of concentrate through autogenous grinding as a substitute for ballmilling. Fine screening of intermediate concentrates was employed advantageously, but the frequency of blinding may be a factor militating against use of the screen in this flotation system.

Jan 1, 1973

Rank the dust knockdown (airborne capture) ability of six different types of water spray nozzles, Approach A fixed quantity of dust is released into a large, closed chamber in a laboratory. Water sprays are turned on inside the chamber and their effectiveness on the dust cloud is evaluated from the rate at which the dust disappears. This method better simulates dust suppression underground than methods tried earlier. The results of the laboratory test were confirmed by conducting tests on a full-scale mod-el continuous miner face where dust levels were measured in the return airway. Results of the Closed Chamber Tests The graph indicates that atomizing nozzles provide the best use of water for dust scrubbing. However, use of these nozzles is limited by their susceptibility to damage and clogging. Hollow-cone nozzles perform almost as well as atomizing nozzles. Test results also indicate that full-cone, venturi-assisted, and flat-fan spray cones are about two-thirds as effective as hollow-cone nozzles. The least effective were venturi nozzles designed for moving air. The most significant advantage of hollow-cone nozzles over other nozzles tested is reduced clogging due to larger orifice size. The hollow-cone nozzle used in the test and depicted by the graph was type BD-3 manufactured by Spraying Systems Co., Wheaton, IL. This nozzle is already used on many continuous miners. Other hollow-cone nozzles of

Jan 1, 1982

By J. C. Franklin

The Spokane Mining Research Center of the Federal Bureau of Mines is placing major emphasis on chemical stabilization as part of the ground support program. Development of polymeric material suitable for bonding rock fractures around the mine opening is one phase of the program. Some of the problems that must be considered are viscosity, applicability, adhesion, cure times, strength, toxicity, and flammability. Epoxies and polyesters were investigated, but shrinkage in polyesters caused redirected effort toward epoxies. Test results with the latter showed that bonded fractures in mine-roof strata were stronger than the virgin rock. Further tests showed that polymeric materials have good potential for bonding, and in conjunction with polymer roof bolts, are expected to result in an economic and useful new support concept.

Jan 1, 1974

By E. D. Gardner

"The Bureau of Mines receives many inquiries concerning favorable areas in which to prospect for gold, procedure to be followed, equipment required, and allied subjects. This circular has been prepared for use in reply to these inquiries.Interest in gold mining and prospecting for gold remains steady. From time to time many people take to the field to search for new gold deposits. A large percentage of them have had no previous experience in prospecting for lode gold; this paper has been written with the hope that it might assist these newcomers.A majority of the metal mines in the United States have been discovered by qualified prospectors who were searching for valuable minerals at the time. Chance, however, always has played a large part in finding mineral deposits. Some of the discoveries of the past were made by men on other errands, such as rounding up burros or hunting game. Accidental discoveries of ore bodies have been made in building roads and trails and in excavating for mine struc¬tures. Evidence of ore has been brought to the surface by burrowing animals and by ants; gold found in the craws of fowl has led to discoveries of deposits. Important discoveries have been made by men who had no knowledge of rocks or minerals; on the other hand, many ore bodies have been found by experienced prospectors, sometimes after hundreds of untrained men had already passed over the ground.The prospector who carries on his work diligently and intelligently is of course more likely to be rewarded for his efforts than the lazy or unintelligent worker; nevertheless, it is obvious that if valuable deposits are not present at the place being prospected none will be found. Conscientious and painstaking efforts to trace gold to its source usually disclose nothing more valuable than some narrow, unworkable seams; however, many deposits that were developed into profitable mines were found by this method of prospecting. Although some prospectors have made several lucky strikes, many others have spent their working lives searching for gold without finding anything worth while. Probably only one prospector out of several thousand ever finds anything worth developing. Moreover, only 1 out of every 300 or 400 properties developed becomes a profitable mine.Prospecting was begun in the Western States in the fifties as the miners looked for the source of gold found in placers. The search for gold has been continuous since that time; the number of prospectors in the field at any one time, however, has varied greatly. Except in some desert regions, practicallyall of the placer fields now being worked were discovered by old timers; more-over, most of the important gold districts were found by early prospectors. Important discoveries of lode mines, however, have been made from time to time. Most of the area in the mining regions of the West has been searched many times by prospectors, and nearly all of the easily found deposits have been located, but it is reasonable to expect that new gold mines will continue to be found. Most of the future discoveries undoubtedly will be of deposits that do not outcrop. Prospecting for such deposits requires considerable digging.Several important discoveries were made in 1934. One of these, the Rogers-Gentry gold mine at the edge of Antelope Valley in Los Angeles County, Calif., was found by an experienced prospector on an old patented homestead a number of miles from the nearest producing mine. The initial discovery at this mine was an iron-stained, decomposed, silicous limestone outcrop, with no vein structure evident at the surface, near a small, barren quartz outcrop and a water seep. Another discovery, the Silver Queen gold mine, in the same general region and near Mojave, Calif., was found by an experienced miner on an open fraction 400 by 1,400 feet in size between two old properties that were thought to have been worked out years ago. The Silver Queen discovery was made as the result of finding a"

Feb 1, 1950

By Richard L. Rains

The Bureau of Mines conducted a mineral investigation of the 29,000-acre Dixie Summit area near Elk City, Idaho, during the summer of 1989. At the Petsite mine a marginally economic, identified resource of 4.9 million tons with an average grade of 0.023 ounces gold per ton was delineated. Possible resources of gold, along with silver, copper, lead, and zinc, occur in at least eight other lode deposits. Placer gold may be recoverable by recreational-sized suction dredges in some stream drainages, Five lode mines in the study area have produced over 5,516 ounces of gold (placer gold production was not recorded), 4,757 troy ounces of sliver, 36,746 pounds of lead, and 3,800 pounds of copper. Current mining claims in or adjacent to the study area total 460 lode and 70 placer claims. There are two patented lode claims within the Dixie Summit study area.

Jan 1, 1991

Monitoring systems can have numerous uses in the mine. They can aid in the efficient management of the mine by providing environmental trend data, production and maintenance control, and communications. In some cases, they can provide justification to petition the Mine Safety and Health Administration (MSHA) fog a variance of one of the mandatory safety standards. They may also increase the gross revenues of the mine by increasing the amount of coal produced or increase profits by reducing the cost of producing that coal. No single system will satisfy the requirement of all mines. Some may require simple hard-wired status-reporting systems; others, multipurpose computer-based systems that collect, analyze, and store data and perhaps control some mine functions. Even though systems vary in complexity, they are all composed of three functional components. The first component is sensors that measure the environmental or production parameters and produce an electrical signal that is fed into the telemetry. The second is telemetry devices that receive the signal from the sensors and transmit it in either analog or digital format to the third com¬ponent, analysis and display equipment. This equipment receives the transmitted signal and either stores it for later analysis or displays it. The analysis-display equipment ranges from simple strip chart recorders with preset alarms to computers, cathode-ray tubes (CRT's), and line printers that can also provide production reports. 4.2 Uses of a Mine Monitoring System A list of potential uses for mine monitoring systems, including both production-related functions and those related to health and safety, was used to develop a questionnaire. It was presented to representatives of the mining community to determine their current monitoring priorities. The responses indicated that the industry's priorities fall into the following two categories: First priority- Production and haulage Maintenance Second priority- Ventilation Communication Fire monitoring Personnel The survey shows that production-oriented systems were the most appealing to the questionnaire respondents. Since even small improvements in production efficiency and maintenance can have a large financial impact, the desirability of monitoring systems that focus on these areas is understandable. The results are summarized in table 4-1. The function that scored 100 was viewed as the most beneficial monitoring function.

Jan 1, 1984

By J. M. Harrington, C. W. Owings

"The transportation of explosives, and especially their distribution from the supply magazines of the manufacturers or dealers to the mines, quarries, or other points where they are to be used, by means of horse-drawn vehicles is an old-time practice, and the records of accidents of the past show this to have been a hazardous undertaking requiring for safety the taking of many precautions not required in the transportation of other merchandise.Displacement of the horse-drawn vehicle by the motor vehicle for the transportation of explosives is increasing rapidly. A consideration of the facts that the vehicle is operated by an explosion engine, using easily vaporized liquid fuel; that the charges in the engine are fired and the vehicle lighted by electricity; and that the vehicle, being operated insulated from the ground, may accumulate static charges led to the conclusion that new hazards are being introduced into the transportation of explosives through the use of motor-operate& vehicles, and that therefore additional special precautions must be taken against these additional hazards.That accidents have already occurred in this use of motor-vehicle transportation is evidenced from the following examples:Recently in California a driver loaded a box of granular powder in the rear of an automobile truck and a box of electric detonators in the front. Suddenly, while traveling along a highway, the explosives detonated, demolished the truck, and blew the body of the driver into small pieces. No evidence was left to show the cause of the explosion, but it is assumed that a jar or other means caused the detonators to fire, and that they in turn detonated the explosive. It should be recognized that it is unsafe to transport detonators and explosives in the same compartment, and this rule should be strictly enforced. At present this rule appears to be either unknown or, at least, frequently ignored.There are usually so many possible causes of ignition or detonation of a truck load of explosives that it is often impossible to state definitely the exact cause in a given case. This is well illustrated in the following account of an accident: A trucking company was hired to haul a truck load of explosives about 200 miles. The driver had had experience in driving trucks of explosives, and it was stated that he inspected the truck carefully before leaving the garage. Eighty 50-pound boxes of explosive were placed in tiers on each side of the truck and 265 25-pound kegs of black blasting powder were placed in the center of the truck. The boxes were placed flat and the kegs were placed on end, arranged in tiers. While the truck was being driven along the highway there was a muffled explosion. When some men, who were about a quarter of a mile away, arrived at the scene the truck was in flames and they could get no nearer than 100 feet. The driver was sitting in his seat and had apparently been killed instantly either by shock or fumes. When the flames were finally quenched, the driver's body was recovered, badly charred. It was, found that several boxes of explosives had been thrown about 40 feet by the initial explosion but were uninjured. A total of half a ton of dynamite was recovered. The cover to the gasoline tank could not be found."

Aug 1, 1930

By Thomas C. Mowatt

Preliminary Bureau of Mines studies of mafic igneous rocks collected from the Rabbit Creek area, northwestern Alaska, indicated concentrations of platinum (412 to 1,406 ppb) and palladium (343 to 892 ppb) in five of eight samples analyzed. The samples represent boulders and cobbles of mafic/ultramafic rocks from this locality. They are not from outcrop. Petrologically, (on the hand specimen scale) the samples are crudely to well-layered and are troctolitic ± gabbroie in character, with primary igneous mafic minerals strongly altered. Small patches of interstitial sulfide minerals, including chalcopyrite, bornite, pyrrhotite, pyrite, and covellite are associated with these altered zones and elsewhere through the specimens. Copper values ranged from 0.1 to 0.3 pct in samples analyzed semiquantitatively; nickel, cobalt, and chromium contents are low. Chemical, mine alogic, and petrographic relationships suggest that the rocks of similar character outcropping in northwestern Alaska could also be considered as prospective for- concentrations or platinum, palladium, and copper.

Jan 1, 2011

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

MINE VENTILATION NETWORK ANALYSIS

Jan 1, 1977

As part of remote sensing research on an abandoned mine lands (AML) site in the Colorado Springs, Colorado area, a geographic information system (GIS) database was generated. This GIS database contains information on the locations and extents of abandoned underground coal mines, the geology of the area, subsidence features and degrees of subsidence risk, topography, drill hole locations, and lineaments (linear features) related to subsurface geologic structures. A GIS database allows the reproducible and accurate comparison and analysis of any data sets which geographically overlap and are within the same coordinate system. The database has been released to the public domain so that government agencies, researchers, educators, and the general public can access this coherent database for the purposes of better understanding the study area and GIS technology. Data files and maps are available in formats that are compatible with the GIS software used in the research project and with most CAD systems so that as many people as possible can make use of the majority of the database. This document serves as the data dictionary for the database by providing descriptions and origins of the data files.

Jan 1, 1992

To provide accurate navigation and control of continuous mining systems.

Jan 1, 1996

By Richard L. Lewis

This is a discussion of the application of the zonal harmonic series to problems involving dipole sources in the vicinity of spherical boundaries. The application of a formal zonal-harmonic series solution to directly obtain numerical results involves two distinct problems: namely, the convergence of the series solution and the accurate calculation of the special functions involved in the series solution. Some interesting techniques will be introduced which help to improve the convergence properties of the series solution.

Jan 1, 1973

Roof bolting is a slow, expensive, and absolutely necessary mining activity. Roof-bolting activities also account for the largest percentage of lost-time injuries in underground coal mines. Dull bits result in the application of excessive force, which bends drill steel; and changing starter and finisher steel was the most significant source of injuries associated with roof bolting. The tungsten carbide (WC) roof-bolt drill bits currently used in American, Canadian, and Australian coal mines are capable of drilling only one or two 4-ft holes and then they are resharpened once or twice to drill another one or two holes. Often, in medium-hard rock formations (sandstone), as many as 20 to 30 bits may be required to drill a single 4-ft hole. Objective To compare the performance, longevity, and cost of newly developed polycrystalline diamond compact (PDC) roof-bolt drill bits against WC bits. Research and Background Diamonds for industrial use have been scarce throughout history and continuous attempts have been made to produce synthetic diamonds. The first synthetic diamonds were manufactured in 1953. Economically produced synthetic diamonds are 1 to 10 µm in size, but in this size range, they are totally unsuitable for industrial applications. In 1972, General Electric Co. developed a process to sinter the artificially developed, minuscule diamond particles into usable products. In this process, several layers of diamond-particles-and cobalt mixture are overlaid on WC substrates and sintered at 2,350° F and 1,000,000 psi. The final product is known as PDC. Today, PDC's are available in many shapes, but their size is limited to 3/4 in, or less, in length or diameter, because pressures greater than 1,000,000 psi are required to manufacture larger PDC's. At present, diamond and PDC arc the hardest and strongest commercial materials available for wear surfaces. The PDC used in this study had a hardness 3.61 times greater than that of WC.

Jan 1, 1992

A revolutionary development in blasting materials has occurred in the past 5 years. Ammonium nitrate, sensitized by the addition of a few percent of No. (class) 2 diesel fuel or other suitable petroleum product, has been adopted as a low-cost, efficient blasting agent2/ by a wide variety of mining and heavy construction operations. Moreover, ready availability of the component supplies throughout the Nation and ease of their formulation into effective blasting agents have made it possible for the blaster himself to pre-pare the mixes at the site of use. Although these field-mixed products have partly or wholly displaced explosives such as dynamites in some applications, there are other blasting operations where the fuel-sensitized ammonium nitrate agents do not appear to be well adapted. Important safety characteristics are inherent in ammonium nitrate-based blasting agents prepared under competent factory control, or when field mixed under equivalent close control--as long as the hazards they present are clearly understood and respected. This publication attempts to summarize knowledge of those hazards and to incorporate practical ways to cope with them. A series of safety recommendations thus is presented. These recommendations cover the preparation, storage, transportation, and use of field-mixed ammonium nitrate blasting agents.

Jan 1, 1960

By M. L. Whisman

Radiotracer techniques were developed for stoichiometric studies of photochemical reactions associated with atmospheric smog formation. Stock blends of separate hydrocarbon and oxygenated compounds were prepared and calibrated. 14C-labeled reactants and products in reaction systems involving hydrocarbons and nitrogen oxides at the ppm level were analyzed for qualitative and quantitative data. Precision and accuracy of these methods developed by the Bureau were determined by replication and statistical treatment of data, and these methods are described.

Jan 1, 1969

By Linneas W. Laage

Coal production from underground coal mines has been important to the development of the industrial economy of the United States. Environmental problems have developed from some abandoned operations. These problems include: mine and refuse pile drainage, subsidence, unsafe mine openings and to a lesser extent mine gases, slope stabilities, mine and refuse pile fires and abandoned equipment and structures. Field investigations in three eastern coal mining districts, two in Ohio and one in Illinois, were performed to document the mine closure procedures used and subsequent problems that developed. The purpose was to identify, evaluate, and rank the seriousness of these problems. Based upon this evaluation, the undesirable present day situations could have been avoided or at least minimized by varying certain mining practices or mine closure procedures. It was found that federal regulations address all of these problems during the pre mining, active mining and post mining phases except for abandoned equipment which is the least threatening problem category. Ideally current practice would prevent future problems. However, the extensive and complicated nature of the legislation, environment and mining practices will necessitate adjustments to the law. The investigator recommends the following: 1) Goal oriented legislation encouraging complete resource extraction, standardization and compilation of mining generated hydrological data, periodic review of the coal mining regulations, and improved communication and cooperation between coal interests, regulators and the public. 2) Permitting effluent limitations to accurately reflect natural conditions. 3) Solidly back filling shafts and individual assessment of sealing or capping requirements. 4) Installing shaft vent pipes into the fill material to intercept and vent methane.

Jan 1, 1982

By Stephen C. Tadolini, Thomas M. Barczak

Roof support systems, longwall shields in particular, have persistently grown in size and capacity for the past 25 years. Why is this? Is it a good thing or is it unnecessary? What are the consequences of this “bigger-the-better” design philosophy? Rarely do we see a “one size fits all” approach to roof support except when it comes to longwall shields, where the historical trend for new procurements is to simply purchase the highest capacity support you can buy. Does high capacity ensure failures will not occur? The answer is no! The highest capacity tailgate supports are typically the ones that fail the most often. What does this tell us? It tells us that there are fundamental aspects of support design and ground control that we still do not understand or recognize when designing a support system. This paper provides an interesting evaluation of these issues and proposes a different approach to support design that attempts to match the support performance characteristics to the ground behavior. Along the way, some of the old premises of support design will be discarded, and new “controversial” ideas developed. Thinking outside the box never hurt any industry. Mining has made it a common practice.

By F. E. Armstrong

The Bureau of Mines has conducted a research program to systematize the art of locating uncharted and lost oil and gas wells that penetrate coal seams; this publication presents a preliminary summary of its findings. Although no method or combination of methods will guarantee finding all uncharted and abandoned wells in a particular area, at least 75 percent of such wells can be located by compiling and applying all available information and using modern metal detectors.

Jan 1, 1973

By L. C. IlsLey, M. W. Means

The United States Bureau of Mines under provisions of Schedule 20 issues approvals covering complete operating units such as loading machines, room hoists, and storage-battery locomotives. Certain manufacturers design and build entire machines. Other manufacturers purchase a part or all of the electrical accessories from manufacturers of electrical equip- ment and assemble them, thereby making up a permissible unit. Before the assembler purchases electrical accessories for use in such contempla.ed units he may require certain information from the accessory manufacturer as to whether these par- ticular accessories are suitable for assembly in his proposed permissible outfit. In order to aid accessory manufacturers in marketing their product, a provision was incorporated in Schedule 20 whereby tests might be made on individual accessories and reports rendered as to the suitability of a given accessory for use in permissible assemblies. The section of Schedule 20 which permits this special work reads as follows:

Jan 1, 1932