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By Oliver Bowles

"INTRODUCTION Slate has earned a high reputation as a roofing material, carefully selected and properly placed it is rainproof, attractive, and extraordinarily durable. Despite there qualities in its favor, the slate industry during the past 30 years has suffered marked reduction in volume of sales. An increase in building construction and general improvement in business will doubtless bring renewed activity, but considerable ground has to be recovered before the industry can become prosperous. Influences tending to dwarf this long-established industry producing materials of world-wide reputation are analyzed briefly in the following pages in the hope that they may be rectified.HISTORY OF SLATE PRODUCTIONFigure 1 shows graphically the rise and fall from year to year of sales of roofing slate since 1885. In quantity, the peak was reached in 1902, and the most serious decline was from 1912 to 1918, sales at the end of this 6-year period being only one third those at the beginning. Unlike most building materials, slate experienced only a slight recovery in volume of sales during the post-war period, 1920-29. The value closely parallels the volume up to the World War period. Subsequently, however, as unit values increased the aggregate value rose sharololy above the volume curve, attaining in 1928 the point reached in 1903, although the Lumber of squares sold was scarcely one third as great. The increased unit value was due partly to larger sales of heavy architectural grades."

Nov 1, 1933

By J. R. Thoenen

Profits in the crushed-stone industry, as in any other, represent the difference between selling price and production cost. When consumer demand increases rapidly, as occurred in the crushed-stone industry from 1918 to 1927, selling prices tend to rise. Cost of production usually rises, also, owing to the expense of expanding facilities, searching for and developing new quarries, and purchasing, installing, and operating new equipment. Frequently, also, the inattention of managements to the details of operating costs is responsible for their increase. This is not due to negligence but rather to the necessity of confining attention to the problems involved in producing material to supply orders. When market conditions change and consumer demand becomes stabilized or contracts, the producer's attention usually is directed to assuring the orders necessary to keep his enlarged facilities busy. Hence, competition increases and soiling prices decline.

Jan 1, 1939

By Richard A. Dick

This Bureau of Mines report describes the evolution of modern-day blasting agent and slurry products and the state of the art of the usage of these products as it exists today. The steadily increasing consumption of blasting agents and slurries at the expense of cartridged high-explosive usage is related. Although safety is not covered in depth, reference is made to pertinent safety literature available. Product formulations, detonation reactions, and detonation products are discussed. Product terminology is defined and the significant differences between the relatively insensitive modern-day dry blasting agents and slurries and cap-sensitive high explosives are described. Blasting agent and slurry properties are discussed, as well as methods of determining and describing these properties, and specific types of products are also discussed with reference to their ingredients,-properties, and field applications. Increasing consumption of slurries, particularly in small-diameter boreholes, and the development of more cap-sensitive varieties of slurries are forecast although dry blasting agents should continue to dominate the market. The consumption of cartridged high explosives will level off or gradually decrease.

Jan 1, 1972

By J. M. Pugliese

The Bureau of Mines, in support of its overall goal of helping to meet future U.S. demand for minerals, undertook this study to aid the quarry entrepreneur and/or operator in developing quarries near urban areas. In response to increased environmental concerns, the quarry operator often must take steps beyond those required in the last decade toward gaining permits for quarrying near metropolitan areas. Following the steps suggested in this report should increase the chances to obtain the permits to open and develop a quarry. Each task and question in the general plan flow diagrams are described in detail, with the flow diagrams aimed at the goal of acquiring the necessary permits. The appendixes include (1) types of projects for which Environmental Impact Statements (EIS's) may be prepared and Federal agencies responsible for preparing them, (2) State contacts for information regarding environmental impact assessment requirements and mining and mineral land reclamation laws, (3) a checklist of environmental inventory factors, (4) a tabulation of different regulations that affect mining in Michigan and the number of townships and counties that have each of the listed regulations, and (5) environmental logic associated with site selection. A central recommendation is that the quarry entrepreneur and/or operator coordinate plans at the beginning with local government officials (such as township supervisors and/or city and county planning board members), State and Federal officials, and public groups that will be affected.

Jan 1, 1979

By J. W. Paul

The United States Bureau of Mines has made a study of roof control in 68 mines operating in the Pittsburgh coal bed in Pennsylvania, West Virginia, and Ohio. In making these studies, much information was also obtained on various exact methods of development and pillar extraction as practiced by this large group of mines. It is proposed in this paper to describe these methods, by which this group of mines in 1931, a year of reduced industrial activity, produced 28,123,000 tons of bituminous coal - 7.4 percent of the national production for the same year and an amount equal to the combined production of the coal mired in the States of Alabama, Colorado, New Mexico, Utah, and Wyoming. The results of these studies, insofar as they pertain to the prevention of injuries from falls of roof, have been published by the Bureau of Mines. In this paper only a few mines typical of each system will be described; however, should the reader be interested in other details with respect to these mines, he may refer to the following publications: T.P. 522, 1932, 43 pp. Falls of roof and coal in mines operating in the Pittsburgh coal bed in Marion and Monongalia Counties, W. Va., by J. W. Paul and J. N. Geyer.- A study of nine mines in these two counties of northern West Virginia.

Jan 1, 1935

Phase I of U.S. Bureau of Mines contract H01220S3, "Improved Sensors and Fire Control Systems for Mining Equipment, II was an investigative effort involving study of the fire problem and preliminary design of a fire protection system. Overall contract objectives included three basic efforts: * Identify problems * Develop a design * Demonstrate a system The first two efforts were conducted during the period June through November, 1972. Phase II will involve testing of system components; construction and testing of a mockup; and demonstration of the system on a truck to prove its effectiveness under actual operational and environmental conditions.

Jan 1, 1972

By L. R. Stark

Two wetland simulation experiments were carried out in order to determine the effects on manganese retention of several wetland design parameters, including flow rate, inlet pH, carbon supplementation, substrate type, and surface free water depth. The primary aim in each experiment was to determine if sustained manganese retention could be accomplished under the specific experimental treatments. If successful, these experiments could recommend design parameters for the construction of field wetland systems for manganese treatment. Crushed limestone clearly was superior to spent mushroom compost with respect to manganese retention. The presence of free surface water detracted from manganese treatment, while lower flow rates enhanced manganese treatment. Sustained manganese retention was achieved using crushed limestone as the substrate coupled with an absence of surface free water, under inlet water conditions of pH 7.0 and no appreciable iron. Sustained manganese retention was not achieved under reducing conditions using spent mushroom compost while varying flow rate, inlet pH, and carbon supplementation regimes. However, lowering the flow rate resulted in many significant beneficial effects on outlet water chemistry: lower outlet manganese concentrations (over the short term), higher outlet pH, lower outlet acidity, higher outlet alkalinity, higher outlet sulfide, lower outlet sulfate, and lower outlet redox potential. Supplementation of the wetlands with dairy whey resulted in lower outlet manganese concentrations (over the short term), marginally higher outlet sulfide levels, and acted to lower the redox potential under the high flow regime. Wetlands receiving a neutral pH had lower outlet acidity, higher outlet alkalinity, lower outlet sulfate, but equivalent outlet manganese concentrations than wetlands receiving an acidic pH. When manganese is the primary mine water contaminant and a passive water treatment system is to be used, it is recommended that crushed limestone with negligible surface water be used in place of composted materials. This recommendation assumes a source water with circumneutral pH and an absence of other metals.

Jan 1, 1993

By James L. Elder, J. P. Capp, James J. Dowd

The Bureau of Mines and the Alabama Power Co., jointly, conducted the first experiment undertaken in the United States in underground gasification of coal in place, at Gorgas, Ala. Milton H. Fies, manager of coal operations, Alabama Power Co., proposed the cooperative investigation to Arno C. Fieldner, chief, Fuels and Explosives Branch, Bureau of Mines; and assisted in supervising the experiment. The objectives of the experiment were to determine whether coal in place could be burned successfully and whether the burning could be controlled; the effect of the fire on the coal bed and the overlying strata; and the yield and quality of gas that could be obtained.

Aug 1, 1947

By S. R. Zimmerley

As a result of the drilling program of the :Mining Division, Bureau of Mines, large amounts of manganese ores have been blocked out in the Drum Mountain District of Utah. The ores, as mined, would not be acceptable for the production of ferromanganese, and this investigation was made to determine their amenability to concentration by ore-dressing methods and the amount of

Jan 1, 1942

By S. R. Zimmerley

As a result of the drilling program of the Mining Division, Bureau of Mines, large amounts of manganese ores have been blocked out in the Drum Mountain District of Utah. The ores, as mined, would not be acceptable for the production of ferromanganese, and this investigation was made to determine their amenability to concentration by ore-dressing methods and the amount of

Jan 1, 1942

By Edmund S. Leaver

[In previous reports5/ of ore-testing studies standard methods of conducting; test with precious-metal ores selected as representative of certain mining districts were discussed in considerable detail. In addition to standard tent procedures such as direct cyanidation, amalgamation, gravity concentration, and flotation, or a combination of these methods, it is sometimes necessary to apply other methods, such as preliminary roasting and washing of the calcine with plain or acidulated water before cyanidation. In all of this work standard tenting procedure has been supplements by he necessary assaying and analyses of original ore and test products.]

Jan 1, 1941

By Edmund S. Leaver

[In previous reports 5/ of ore-testing studies standard methods of conduction tests with precious-metal ores selected as representative of certain mining districts were discussed in considerable detail.]

Jan 1, 1941

By Russell R. Trengove

The largest potential reserves of manganese in Nevada are in the Pioche district. To date, these large reserves of 10-to l2-percent manganese cannot be upgraded economically. Other large, low-grade deposits, such as the Virgin River and Boulder City deposits in Clark County, cannot be considered immediate sources of manganese. Reserves of the principal manganese deposits in Nevada, based on the most reliable estimates, total about 17 million tons analyzing 7.6 to 13.6 percent manganese. Most of the deposits are of a type that cannot be prospected systematically but have been prospected and developed in the course of productive mining operations. To realize production from low-grade deposits that are amenable to concentration, a ready market must be provided. Thus far, Government stockpiles have been the major outlet for these low-grade ores. Research and experimentation over a period of years have led to development of several processes technologically applicable to these low-grade ore bodies, but their economics is not sufficient to allow competition with imported ores on the open market.

Jan 1, 1959

By Oliver C. Fursman

The Bureau of Mines undertook this investigation in order to determine the feasibility of producing commercially acceptable alumina and iron by application of the Pedersen process to high-silica, high-titania, ferruginous bauxites of the Pacific Northwest. Calcium aluminate slags were produced by smelting bauxite with coke and lime in an electric-arc furnace. Over 90 percent of the total alumina can be extracted by sodium carbonate solution from slags of properly controlled ternary-phase composition (CaO-Al203-SiO2) that are cooled slowly enough to permit adequate crystallization of the 2CaO-SiO2 and the calcium aluminate compounds. Most of the iron charged was recovered in the regulus; the slag contained about 2 percent iron (as iron oxide), regardless of smelting time.

Jan 1, 1968

By James E. Cairelli

The NASA Lewis Research Center, under U.S. Bureau of Mines program direction, performed an assessment of alternative mobile power sources for mining applications. A wide variety of heat engines and energy systems was initially examined to ascertain which could be considered as potential alternatives to presently used power systems. The present mobile power systems are electrical trailing cable, electrical battery, and diesel - with diesel being largely limited in the United States to noncoal mines. Each candidate power source was evaluated in terms, of the following requirements: (1) Ability to achieve the duty cycle (2) Ability to meet Government regulations (MSHA certification) (3) Availability (production readiness) (4) Market availability (5) Packaging capability An initial screening reduced the list of candidates to the following: (1) Diesel (2) Stirling (3) Gas turbine (4) Rankine (steam) (5) Advanced electric (batteries) (6) Mechanical energy storage (flywheel) (7) Use of hydrogen evolved from metal hydrides This list of candidates was divided into two classes of alternative power sources for mining applications - heat engines and energy storage systems. A summary of each class follows.

Jan 1, 1981

The principal activities of the Bureau of Mines Explosives Research Center during fiscal year 1969 (July 1: 1968, to June 30, 1969) are reviewed in part 1. Part 2 presents short abstracts of the publications issued during this period in the Bureau series and in the outside press. These publications are referenced in part 1 by underlined numbers in parentheses. Other publications, which are not abstracted, are cited in footnotes throughout the paper. ACKNOWLEDGEMENTS The Bureau acknowledges the support received through cooperative agreement in fiscal year 1969 from the Manufacturing Chemists Association. It also acknowledges the sponsorship by the following Government agencies of research conducted during that period: Department of the Air Force, Department of the Army, Department of Health, Education, and Welfare, Department of the Navy, Federal Aviation Administration, National Aeronautics and Space Administration, Space Nuclear Propulsion Office, and United States Coast Guard.

Jan 1, 1970

By G. B. Shea

"INTRODUCTION Much of the recent progress in increasing the efficiency of oil-well performance can be attributed to advancements in the art of cleaning wells. Through research and development by operators and service companies during the past decade, significant improvements in the application of engineering and chemical principles to well-cleaning technology have widened greatly the scope of ""clean-out"" methods to the end that greater ultimate recovery of oil will be attained.This report reviews recent improvements and developments on this important problem in California; it describes also the use of various methods and tools for cleaning wells to stimulate or revive their productivity. Developments in preventing and removing mud sheaths in well-completion operations also are described. The report is based on a field survey, supplemented by data from the technical and patent literature and from manufacturers' catalogs, which contain much valuable information.In preparing the material for publication as a Bureau of Mines report, the author has been fully aware of certain limiting conditions that attend the discussion of a subject such as that treated in this report. The following are examples:1. To a considerable extent, well cleaning in California is done with tools rented from service companies, and their representatives and employees are specialists in jobs of this type. They usually have working experience with their own equipment and methods which greatly exceeds that of persons whose interest has been casual or who have had no opportunity to study the subject in detail in actual practice. Many of the tools and methods are covered by letters patent for the protection that may be in developing and successfully applying these mechanical and chemical means of increasing the production of wells. Frequently several years have been required to perfect a given tool or technique, requiring relatively large investments to establish a service that is remunerative to those who have primary interest in a certain development and at the same time attractive enough to the operators of producing properties (because of greater quantities of oil delivered into the flow tanks) to warrant employment of or contractual agreements with a particular service group."

May 1, 1943

By Harold W. Lipper

BUREAU OF MINES helium plants produced a. record-breaking 477 million cubic feet of this essential element in 1959. The supply of helium was less than the demand before operations were resumed at the Navajo plant in July and begun Sit a. new plant at Keyes, Okla., in August. Helium was in abundant supply after August, and the informal allocation system which had been in use intermittently since 1955 was discontinued Delivery of 26 new tank cars in August and September increased the total in the tank-car pool to 163. Defense and space agencies and the Atomic Energy Commission continued to use more helium in their operations and research.

Jan 1, 1960

By E. L. Rawlins

Systematic leakage surveys of natural-gas transmission lines not only aid in the conservation of gas, but can be made to show direct financial returns of large magnitude. 1. Such surveys reveal the actual leakage from the lines, and indicate repairs to be made in order, to eliminate unnecessary waste. 2. Tests on lines, after repairs are made, show the actual saving that has been accomplished. 3. Tests on newly constructed lines reveal the presence of leakage that should be eliminated before the lines are put into service.

Jan 1, 1926

By Albert L. Toenges

The purpose of this paper is to describe some of the methods and practices of mining coal mechanically where more than one shift is worked, with the view of determining the advantages and disadvantages of various types of equipment and mining systems now in use. This paper is in the nature of a progress report, and, as the number of mines discussed in it is limited, the conclusions drawn in the comparison of various systems are not final but may be revised after subsequent investigations. Physical conditions vary in different and in the same mining districts and determine, more

Jan 1, 1938