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By Raymond B. Ladoo

Toward the end of 1920 , the average grades of ground feldspar offered to the pottery industry were so poor and so generally unsatisfactory that many of the largest consumers decided to take active steps for their own protection . A few of the potters made arrangements to grind their own feldspar , while others asked the Bureau of Mines to make a detailed study of the problem and to suggest methods of improvement . Accordingly such a study was undertaken, the partial results of which are outlined in this preliminary report . The outstanding features of the present feldspar industry which are of interest in this connection are stated below. (1 ) Many grinding companies do not own or control all or even a major part of their sources of crude material , but buy in job lots from many sources . (2 ) There is great need of more adequate engineering and chemical control over mines and mills . ( 3) ~ Out of date , inefficient methods and equipment for mining and grinding are in common use . (4) Little or no cooperation exists between feldspar producers , but on the contrary many feldspar companies are exceedingly secretive . This tends towards (a) preservation of obsolete methods ; ( b ) want of knowledge of the essential features of production , market requirements , and the relation between total milling and consuming capacities of the country; ( c ) inefficient and often mistaken trade practices ; ( d) unprofitable and even ruinous competition in dull periods . (5) The small size of many feldspar deposits precludes maintenance of an efficient organization at each individual mine . ( 6 ) Many of the best deposits of feldspar situated close to railroads are becoming depleted , which results in gradual lowering of grades , and increase in cost for better grades . (7) There is a lack of exact mowledge of the ceramic properties and behaviour of feldspar by some consumers , which results in ( a) purchase of feldspar on the basis of price alone , thus encouraging low production costs at the expense of quality , and ( b) inefficient and expensive cross- hauling of both crude and ground feldspar .

Jan 1, 1922

By George H. Schnakenberg

Automation of coal mining activities at the face offers improvements in worker safety, health, and productivity. Introduction of integrated computer-sensor systems to current mining machines will enable these machines to perform some of the most hazardous tasks through supervised teleoperation. The U.S. Bureau of Mines is pursuing the development of the enabling technology necessary to achieve this goal. The research program consists of both basic and applied research, each focused on the fundamental issues of computer and sensor technologies. Short-term research is directed to providing computer-assisted, remote supervisory operation of present underground equipment; the long-term goal is the development of progressively more intelligent mining systems. The research program includes a review of robotic machine and autonomous vehicle technologies and of current mining technology, which provides a base for developing innovative mining methods; research in navigation and guidance technology, emphasizing control of a continuous mining machine; research on coal-rock interface sensing technology for horizon control, and rib thickness control in highwall mining; the development of computer systems and hierarchical architectures for real-time control; and development of expert systems for machine system fault diagnostics and predictive maintenance. This report presents a brief background and the current status for each of these research areas.

Jan 1, 1989

By Allen D. Look

Uninterrupted shaft operations are an important economic factor in mine operation, and good shaft support is an important aid in preventing accidents and interruptions. More permanent supports can cut the hazards, costs, and delay incident to replacement of conventional timbers, especially where subject to decay. Installation of prestressed, precast concrete shaft supports in 100 feet of shaft at the Banner mine, Lordsburg, N. Mex., nave a satisfactory permanent installation in a section of shaft that had given trouble with conventional timbering. Use of rock bolts supporting gunited wire netting around the rock walls of the shaft prevented sloughing. No attempt was made in this paper to arrive at comparative costs of installation of various types of support. However, it was indicated that use of a lighter weight aggregate would be desirable in further use if prestressed precast members as placed in the Banner mine.

Jan 1, 1957

By J. H. East

Potash is one of the essential chemicals used in fertilizing soil deficient in natural minerals . Europe uses a large tonnage of potash in the form of easily soluble salts , and this is particularly true of those countries where the natural minerals in the soil have been exhausted owing to intensive cropping of the land . The application of potash to the soil in these countries is essential if normal crops are to be obtained ; during the war , some European countries were unable to obtain sufficient potash , and productivity of the farming areas declined seriously . • The largest -known deposits of potash in the world ; with the possible. exception of Russia , occur in Germany , and the German output of processed salts constituted about 65 percent of world production prior to the war . The German potash-plant installations are large , modern , brick and steel construction and apparently built for a planned operation of many years . Two districts produced approximately 80 percent of the German potash; the Werra -Fulda district , near Vacha , had the largest production , and the Sudharz district , near Nordhausen and Sonderhausen , was second . (Fig . 1. ) Hannover and Stassfurt were two smaller producers . Potash fertilizers are rated in terms of potassium oxide (K20 ) . The usual basis for calculation of production or application of the salt is to reduce the potash content to 40 percent K₂0 .

May 1, 1947

By John J. Mulligan

The Bureau of Mines investigated reports of mineral deposits within 10 miles of the route of the proposed pipeline from Prudhoe Bay to Valdez. No producing lode deposits or lode prospects of possible national economic significance were found. Measured placer deposits in the route are or slight value except possibly some deeply buried gold placer deposits in the Fairbanks and Livengood Quadrangles. The pipeline corridor crosses five belts of minerals having potential economic value: (1) The north slope of the Brooks Range (oil, gas, oil shale, coal, phosphate); (2) the south slope 01 the Brooks Range (copper, gold); (3) the Livengood area (gold); (4) the Fairbanks area lead-silver, antimony); and (5) the Wrangell Mountains-Denali copper belt (copper-gold). The Jarvis Creek coalfield, an eastern extension of the Nenana coalfield, is on the north side of this belt. Scattered along the corridor across the Chugach Mountain and in the vicinity of Valdez are a wide variety of metallic deposits that make up the eastern margin of the Chugach gold belt but do not seem to constitute a well-defined zone.

Jan 1, 1974

By W. W. Adams, T. D. Lawrence, D. R. White

"This paper presents the results of the eleventh yearly accident-prevention contest, the National Safety Competition of 1935, conducted by the United States Bureau of Mines. Participating in the competition were 336 mines and Quarries in 37 States. Five mining or quarrying companies, each the leader in its group for having established the best safety record during the year, were awarded the national safety trophies 'Sentinels of Safety.Since these annual contests were begun 11 years ago the scope of the competition has been broadened materially, both as to the number of plants participating and as to the number of man-hours of exposure to accident hazards. Moreover, marked progress in the pre¬vention of accidents has been achieved, as is indicated by an almost constant downward course in the accident-frequency rates for the contest group as a whole during the past 11 years. On the other hand, the accident-severity rates for the group showed an upward trend during the first part of the period and a downward trend during the latter part, except in 1930 and 1934, when two disastrous explosions occurred with heavy loss of life, and in 1935, when there was an increase in the number of fatalities although no major disasters occurred. The accident rate for 1935, both as to frequency and severity, was higher than for 1934.The National Safety Competition is conducted by the Bureau of Mines in the interest of safety in the mining and quarrying industries. This object is accomplished directly through the efforts of the competing companies and their employees to win first place in the competition and thereupon receive well-merited and national recognition for their achievement. Indirectly the purpose of the contest is accomplished through studies by the Bureau of Mines of the fasts contained in the accident reports which the competing companies furnish to enable the Bureau to compute the accident rates that are the basis for determining the winners of the contest.The statistics that constitute the basis for determining the winning companies and the relative standing of all companies are prepared uniformly without regard to the States in which the companies operate, or to differences in classes of accidents covered by State laws relating to compensation for injuries resulting from industrial accidents."

Jul 1, 1936

By Gwendolyn D. Hood

The Bureau of Mines investigated techniques for dewatering slurries from talc-processing operations to improve water reclamation and pro-duce dewatered solids suitable for disposal. Various flocculating reagents were evaluated, and a nonionic polyacrylamide was found to be most effective in a specialized flocculation dewatering technique. The flocculation dewatering method was applied in laboratory batch tests and in continuous tests using a static screen, a belt-roller device, and a clarifier-thickener laboratory unit. In continuous tests using the unit, wastes of 3.5 pct solids were dewatered to 56.9 pct solids using 0.03 Ib of flocculant per ton of dry solids treated.

Jan 1, 1983

By Janke L. W. Jolly

Owing to an upsurge in export earnings. Cameroon made substantial economic Progress in 1978 and 1979. With a real growth estimated at 6%, the gross domestic product (GDP) for 1979 surpassed $5 billion.2 Crude petroleum production was providing a new potential in 1978 and 1979 for achieving national self-sufficiency. Among other benefits, crude petroleum exports were helping to offset the escalating costs of refined petroleum imports and to reduce the 14% to 17% annual rate of inflation. Over the 4 years prior to 1978, Cameroon's petroleum imports increased by 12.1% in volume annually, while the import cost increased by 24.5% annually to about $105 million. Total export earnings for 1978 were $805 million,3 to which crude petroleum contributed $25.3 million and crude aluminum product exports contributed $25.9 million. Petroleum exports had increased to about $240 million in 1979 and were in third place after coffee and cacao. Total imports for 1978 were valued at nearly $1 billion. The volume of petroleum imports decreased in 1979 to 552,000 tons, compared with 622,000 tons in 1978. The European Economic Community (EEC) countries purchased over 75% of total Cameroonian exports and provided most of the Nation's imports. The United States purchased $12.4 million in petroleum exports from Cameroon in 1978. Domestic consumption of aluminum metal from imported Guinean alumina continued. to grow; thus exports of this metal to France (valued at $2 million in 1978) and Japan

Jan 1, 1981

By Efrem R. Reeves

Noise-induced hearing loss (NIHL) is the most common occupational illness in the United States, with 30 million workers exposed to excessive noise levels [NIOSH 1996] every day. Of particular concern is the mining industry; which has the highest prevalence of hazardous noise exposure of any major industry sector [Tak et al. 2009] and is second only to the railroad industry in prevalence of work-ers reporting hearing difficulty [Tak and Calvert 2008]. This document is for operators, safety personnel, and mechanics in the mining industry who are not specialists in noise control engineering or acoustics. Evaluations of successful and unsuccessful attempts at controlling noise on several large, underground metal mining machines are detailed to illustrate the basic principles of noise control. Once personnel understand the guidelines and principles of noise control, they will be able to ¦evaluate the extent of a noise problem; ¦determine the best approach to the problem; and ¦apply the most appropriate solution. Because of the insidious nature of NIHL, it can go unnoticed until a considerable loss of hearing has occurred. In some cases, diagnosis is delayed because an exposed individual claims to have become accustomed to the noise. In reality, that person may have already suffered irreversible hearing loss. Humans can hear sounds in the frequency range from about 20 to 20,000 Hertz (Hz). Within this range, NIHL usually begins in the frequency region around 4,000?6,000 Hz, the upper levels of the speech region. The first noticeable symp-toms include difficulty understanding higher pitched voices, such as the voices of females and children, and difficulty understanding certain consonant sounds, which are primarily high frequency in nature. The extent of NIHL varies depending on the level and duration of noise exposure and on an individual?s susceptibility; despite having similar noise exposure, individuals can experience differing degrees of hearing loss, or none at all. NIHL is almost always preventable. To reduce or eliminate the possibility of NIHL, an individual?s noise environment must be analyzed and appropriate action taken to reduce noise exposure.

Dec 1, 2009

By J. Howard Bird

The purpose of this publication is to discuss grounding mediums and the phases of grounding related to corrosion and cathodic protection. The material presented is believed to contribute to a better understanding of this subject. It also indicates more effective methods of reducing corrosion damage to metal structures and equipment in the mining industry by cathodic protection. The authors do not intend to discuss technical aspects but rather to explain the general principles of this method of inhibiting corrosion. The relationship between soil resistivity, protective grounding, and corrosion is presented. Corrosion causes the annual loss of billions of dollars; which can be greatly reduced. Losses in the mineral industry can be excessive owing to the extensive use of direct-current power, the presence of considerable dampness, and the frequent, indiscriminate use of dissimilar metals.

Jan 1, 1958

By N. Greninger

The Bureau of Mines examined the possibility of a seasonal variation of respirable dust concentration in U.S. coal mines. The first step was to review company and MSHA-inspector dust samples that had been collected during the past several years in 14 selected mines for compliance purposes. Results indicated severe scatter in data; most standard deviations of the dust concentrations measured in winter and summer months were comparable in magnitude with the mean values of dust concentrations for the seasons. Therefore, a detailed statistical analysis was conducted. At the 90% confidence level, the company samples of three mines had winter means 0.15 to 0.54 mg/m3 higher than the summer means; six mines had negligible seasonal variations; and five mines had winter means that ranged from higher to lower than the summer means. Inspector data, however, were too sparse for analysis. In view of both the low frequency of occurrence of a seasonal effect and its wide scatter in several of the mines, the study was ended with the conclusion that seasonal varia-tion in respirable dust levels, in general, is an insignificant factor.

Jan 1, 1986

By S. H. Ash

Tunnel driving is recognized as one of the most hazardous of occupations; this is a reflection of the high accident severity rates and resultant high compensation and similar costs in this industry. Most tunnels are driven by contractors who bid for the jobs, taking into consideration the prevailing industrial insurance rates at the time the bids are placed. After the bid is secured the contractor then attempts to complete the job at the minimum cost to himself. In a sense the accident-cost item is fixed for at least one year when a policy is secured. Time is generally an important factor not only for the contractor, but also for the insurance carrier and the assured. If the assured represents a private interest, the cost burden usually is ultimately placed on the general public which avails itself of the service contemplated; if the project is a governmental enterprise the cost burden unquestionably falls upon the general public involved and on the general tax payer. For these reasons it is of vital interest to the public that accidents not only be kept at a minimum as a humanitarian objective, but also because the accident-cost burden, too frequently not even realized and considered to the degree that it should be, can assume proportions that materially affect the cost of the enterprise. The basic industrial insurance rate for tunneling in California in 1932 contemplated an earned premium of 12.12 percent of the labor pay roll. The State has been particularly engaged in large construction enterprises, some of which involve high accident cost rates, notably structural-steel bridge building, which contemplates an earned premium of 19.65 percent of the labor pay roll. When this figure is compared with the much lower rates that apply to other industries it is apparent that a heavy toll in human wreckage is taken by such engineering projects, which must be viewed as monuments to human suffering as veil as to human achievement.

Jan 1, 1933

By A. K. Schellinger

1. In the United States, the industrial application of centrifugal force for separating phase constituents has been confined almost entirely to aqueous systems at room temperature. This paper presents results for experimental tests on the use of centrifugal force for separating the liquid and solid phases in molten nonferrous alloys. 2. The development and use of a small centrifuge for treating molten metals is described. The centrifugal apparatus was, in essence, a 3-inch diameter spinner pot, which revolved, within -a gas -fired furnace, at speeds up to 3,000 r.p.m.

Jan 1, 1953

By G. W. Birge

The Bureau of Mines investigated the effect of temperature on the mechanical strength of cokes of the type normally used in blast furnace operations. Eight samples of industrially produced cokes were subjected to ASTM tumbler tests at temperatures as high as 1,100° C (2,012° F); these temperatures had no significant effect on tumbler results for cokes with stability indexes of 40.6 to 59.9. Two foundry cokes which were tested at only one elevated temperature (900° C) decreased slightly in tumbler stability. Iron are pellets made from a variety of ores and by various industrial methods were not significantly affected by temperature when tested in an oxidizing atmosphere at 1,000° C (1,832° F) by the tentative standard ASTM method.

Jan 1, 1966

By R. Barany

This paper reports determinations of heats of formation (from the oxides and elements) of crystalline cadmium metasilicate and crystalline lead meta-silicate by hydrofluoric acid solution calorimetry. The results, in conjunction with known entropy values, yield free energies of formation. There are no earlier data of this type for cadmium metasilicate. The results of this investigation for lead metasilicate deviate from the literature values (which are less reliable) in the direction of increased thermodynamic stability. Both cadmium and lead metasilicate are much less thermodynamically stable with respect to their constituent oxides than are the corresponding compounds of the alkaline earth metals.

Jan 1, 1959

By R. D. Leitch

[The accepted theory of acid formation in coal mines with the subsequent appearance of the acid in coal-mine drainage, is oxidation of iron pyrite and subsequent solution and hydrolysis of the iron sulphate formed. It has also been found that 5 gobbed sections and worked-out areas, where there is usually an abundance of iron pyrite-bearing, materials in contact with air, are the sections that make the most important contribution to the quantity of acid drainage. It would thus seem obvious that if oxygen can be kept out of contact with tae acid-forming materials in tie- sections mentioned the amount of acid in coal-mine drainage could be reduced markedly and corrosion problems with mine pumping equipment and general stream pollution mitigated thereby. Although the efficiency of the suggested remedy as been borne out by laboratory experiments6, it has appeared desirable to substantiate the laboratory work by field observations in so far as pertinent data are available. It has been difficult to learn of mines or sections of mines about to be sealed, whereby an actual comparison of the drainage before and after sealing can be made. In view of that difficulty it has been necessary to devote attention to a comparison of the character of the water from areas already sealed with that from open but otherwise comparable sections of the sane mine. Previous cork has shown that the acidity of drainage in different parts of the same mine may vary, but if it can be shown also that the water from sealed areas is with but fen exceptions less acid than the otherwise similar open sections of tae same mine, the laboratory finding will be supported in a practical gray. This report presents some of the evidence that has been obtained.]

Jan 1, 1930

By Raymond W. Hiteshue, Henry H. Ginsberg, Paul S. Lewis

Coal was gasified in the presence of up to 3.57 million roentgens of gamma rays by the Bureau of Mines to determine whether the irradiation increased the gasification rate or yields of methane and hydrogen . High volatile A bituminous coal was gasified with steam at 500 and 1,500 psig and temperatures of 1,400 ° and 1,800 ° F ; five other coals ranging in rank from lignite to anthracite were gasified at 500 psig and 1,800 ° F. The average results of replicate experiments with and without radiation were compared for possible effects of radiation from 40,000 curies of radioactive cobalt . The irradiation had no gross effect on the gasification rate or on the yield and distribution of methane and hydrogen . It was concluded that gammaray irradiation produced no improvement in the technology or economics of coal gasification .

Jan 1, 1964

By E. C. Lane

The motor gasoline that is being marketed in the United States this summer is slightly more volatile than that sold a year ago. The increase in volatility is shown by a lowering of the distillation temperatures, ranging from 2°F. at the average initial boiling point to 4°F. at the average end point. During the past nine years the Bureau of Mines has made semiannual surveys of the gasoline marketed in the United States, the survey just completed being the eighteenth in the series. The cities in which samples were collected have been chosen as representative of the more important marketing territories, as it is obviously impracticable to obtain a sample of every gasoline sold in the entire country. Samples were collected in Omaha as well as in the 11 cities where samples were taken last winter. It was believed advisable to include samples from Omaha in order to give a better balance to the survey for the country as a whole.

Jan 1, 1928

By Leon E. Esparza

In 1985, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied the 16,927-acre Pryor Mountain Wilderness Study Area (MT-067-206), part of the 3,955-acre Burnt Timber Canyon Wilderness Study Area (MT-067-205), and part of the 4,550-acre Big Horn Tack-On Wilderness Study Area (MT-067-207) to evaluate their identified mineral resources. The Burnt Timber and Big Horn Tack-On study areas contain 3,430 and 2,550 acres, respectively. The three areas are in Carbon County, MT, and Big Horn County, WY, about 13 miles north of Lovell, WY. No identified resources exist in any of the study areas. Bureau of Mines personnel reviewed literature, searched county mining records and examined prospects, claims, and mineralized areas to determine whether identified mineral resources existed. The three study areas are within the Pryor Mountain unorganized mining district. U.S. Department of Energy production records indicate there were 223,000 pounds of uranium oxide (U308) and 236,000 pounds of vanadium pentoxide (V205) produced from 19 properties within the mining district. The average ore grade was 0.36 percent [3,600 ppm (parts per million)] U308 and 0.416 percent (4,160 ppm) V20S. Only the Pryor Mountain study area has current claims, the 50 claims of the S0S group.

Jan 1, 1986

By T. G. Carnahan

The Bureau of Mines conducted laboratory-scale weathering research on a leach residue containing elemental sulfur and mixed metal sulfides. Experiments were performed to determine pH and impurity element concentrations in the effluents as functions of time and to determine the effects on effluent concentrations of mixing the residue with dolomite tailing material. Four 800-day tests were conducted simultaneously. Soluble metal concentrations, especially zinc and copper, were excessive in the effluents from washed and unwashed samples of the residue. Concentrations of up to 20 g/l of Zn and 12 g/l of Cu were obtained. The pH values of the unwashed and washed residue effluents at the completion of the experiments were 2.8 and 1.9, respectively. Sulfuric acid from oxidation of pyrite caused the pH decrease. Mixing unwashed residue with dolomite tailing to maintain a near-neutral pH minimized the heavy metals content in the effluents. The pH in the dolomite tests increased slowly after the first 360 days and attained values of 7.8 and 8.2, respectively, for tailing containing 1 pct leach residue and for tailing devoid of leach residue. Dissolved zinc and copper did not exceed 0.10 g/l of Zn and 0.001 g/l of Cu.

Jan 1, 1982