Search Documents

By D. E. Etter, J. E. Selle

HIGH-PURITY cerium metals, supplied as 99.9 pct pure, by various suppliers, vary widely in melting points and in the shapes of the differential thermal-analysis curves obtained as the samples are heated. A definite correlation is noted between the melting point, amount of premelting, and the number of inclusions present in the material. Briefly, the DTA apparatus, previously de-

Jan 1, 1964

By H. William Ahrenholz

The coal industry had another prosperous year in 1966. Since the turn of the decade, production has been climbing at an average rate of 6% per annum. Although the fast pace slackened somewhat, 1966 production showed a gain of almost 3 % over that of 1965. An impressive record can be drawn from the fact that output per man-day in 1966 was more than twice that of the early 1950's, and more than three times that of the early 1940's. And even though man-power requirements lessened, those men retained by the industry worked longer hours and benefited through higher hourly pay rates. However, cost to the customer increased a little. Such statements can only be made for a healthy industry -one that is constantly improving its efficiency. Coal currently provides more than 25% of the total U.S. energy output. About 50% of all U.S.- mined bituminous coal goes directly to the electric utility market. It should be noted that, now, well over one trillion kwh of electricity is generated annually. Dependence of the giant electric utility industry on coal is based on economy and an abundant, dependable supply of this fuel.

Jan 2, 1967

By FRED T. WILLIANS

INTRODUCTION. THE Park City mining-district is distinctively a camp of few properties, 5,000 acres, or one-third of the entire district, being under the management of but three companies. As a rule, the ore-bodies lie deep, with no outcrop, except where erosion has formed the deeper canyons and gulches. Ontario canyon exposed the famous Ontario ledge, and Woodside gulch showed the first ore of the Silver King Coalition mine. The Quincy ore-bodies were first brought to light in upper Empire canyon, and Thaynes canyon was instrumental in aiding the prospector during the early days of the camp. There are 22 shafts which have reached a depth of at least 500 ft., ten a depth of 1,000 ft., five a depth of 1,300 ft., and two a depth of 2,000 ft. The amount of lateral development has been proportionally extensive, including six long tunnels, four of which are in 3 miles, with a fifth now being driven. The Ontario lower drain-tunnel is now more than 4 miles long. The formations are sedimentary, dipping about 30° NW. and N., and traversed by many fissures, dikes, and faults. The principal ore-bodies are found associated either with the contact of the basal Ontario quartzite and the overlying limes, or on a quartzite stratum within the limes, or in the fissures, or along some of the porphyry dikes. The district covers the intersection of the Uintah and Wasatch ranges, which explains the existence of large folds and faults, and fissures of great length, width, and depth. In a general way, the geology of the district consists of a basal quartzite dome, which has been exposed by erosion at the Ontario property. The Ontario fissure lies entirely within this formation. Flanking this dome on the west, north, and east lie

Jun 1, 1911

[Secretary's Note.—The following official tables, prepared by the government of the State of Nuevo Leon, and presented to the Institute at the fifth seseion of its Mexican meeting, held at Monterrey, November 26, 1901, present in compact form a general summary of the mineral and metallurgical industry of the State for the preceding calendar year, together with a statement of the railway-shipments of ores from January 1 to October 31, 1901, which, in the absence of direct official mining and metallurgical statistics (not yet available for that year), clearly indicates an increased activity and productiveness of these industries. In other words, the mines are reported to have yielded in 1900 a total product of 83,960,169 kilos of ore; whereas, the railway is reported to have carried, in 10 months of 1901, a total of 108,318,647 kilos of ore. At this rate, the railway-shipments for 1901 mould amount to nearly 130,000,000 kilos. It is, of course, possible that the railwaystatistics include other freight than ores, or that they include duplications, such as would be involved in the record, first of certain ores transported, and afterwards of the " base bullion " produced therefrom. An accurate comparison is therefore impossible ; yet, after making all reasonable allowances for such items as have been named, it seems safe to infer that the mining and metallurgical industry of this State accomplished in 1901 a substantial progress.]

Jan 1, 1902

By AIME AIME

ON JULY 12, 1921, S. S. Arentz, representative at large from Nevada, introduced in the House of Representatives, under the number H. R. 7736, a bill to revise, amend and codify laws of the United States relating to the location of mining claims on public domain, and other purposes. This bill had been drafted by a committee of consulting engineers of the U. S. Bureau of Mines. The immediate purpose of this introduction in Congress was to make it avail- able for general information and discussion. In pursuance of this purpose Mr. Arentz issued the following circular: This proposed codification and revision of the mining laws of the United States as received from a committee of mining and metallurgical engineers appointed by the Director of the United States Bureau of Mines was introduced in the House of Representatives by the undersigned (who has operated and developed mines throughout the West for many years). It is submitted to prospectors, mine operators and mining engineers, all of whom are affected and vitally interested in the subject with the hope that they will give this bill their careful consideration and study.

Jan 1, 1921

By B. W. Vallat

(San Francisco Meeting, October, 1911.) THE Newport mine, located at Ironwood, Gogebic county, Mich., on the Gogebic iron-range, is owned and operated by the Newport Mining Co., for the mining of iron-ore. I. GEOLOGY. The general geology of the Gogebic range has been determined and recorded at different times by well-known geologists,) and their work will be referred to briefly in connection with the local conditions in the mine. The strike of the formation across this property is about 15° north of east. The, general dip is 68° to the north. At the base of the formation on the south lies the granite. Looking north, at right angles to the strike of the formation, we have the foot-wall of quartz-slates and quartzite about 400 ft. wide; the iron-formation about 800 ft. wide, and the hanging-wall of black slates. The iron-formation is composed of banded jasper and quartzite together with iron oxide and concentrations of iron-ore. In character the ore is a soft red hematite, with occasional masses of hard blue "steel ore." The formation is crossed in many places by diorite dikes, which cut through at various angles, the larger or main dikes dipping into the foot-wall in a SE. direction at angles varying from 15° to 30°, while numerous small dikes occur which strike through the formation in a vertical plane and at approximately right angles to the main dikes. There are various theories concerning these dikes, especially as to the time of their origin with relation to the ore-deposition. The commonly-accepted theory is that the dikes were there first, but there are some who contend that they were formed

Nov 1, 1911

By J. F. Abel, F. T. Lee

Subsidence is controlled by a complex com¬bination of mining and geologic factors. For example, a compilation of worldwide data shows that, as the percentage of shale in the overlying rock mass decreases and the amount of sandstone increases, the angle of draw (and the area affected by subsidence) decreases. Limestone in the over¬burden appears to cause a more than twofold decrease in the angle of draw compared to a like amount of sandstone. Increased amounts of sandstone were accompanied by a greater surface subsidence relative to the mining height. The total thickness of overburden did not appear to influence the subsidence magnitude above super-critical panels. The greater the thickness extracted, the smaller percentage of that thickness shows up at the surface as subsidence. The greater the percent of the seam extracted, the greater the subsidence reaching the surface. The maximum subsidence above room-and-pillar panels de¬pends on the pillar height and minimum width as well as the other factors listed.

Jan 1, 1984

By H. S. Munroe

The dressing-works of the St. Joseph Lead Company were destroyed by fire, February 26th, 1883. Within about four months, or on July 5th, 1883, the new mill, with a capacity of 500 tons per day, was built and in active operation. The capacity of the new mill has since been increased to 800 tons per day. The old mill was built in 1867, by Mr. C. B. Parsons, the present superintendent. It was a curious rambling old structure, which had grown with the demands of the business; a few jigs having been added in one place, a table or two in another and wings and sheds added to the main buildings, from time to time, as it was found necessary to increase the efficiency or the capacity of the mill. The old mill was, moreover, a most interesting place to the student, a perfect "museum of ore-dressing." Nearly every form of dressing apparatus known to the art had, at one time or another, found a place under its roof, jigs of many kinds, concave, convex, side-bump and stationary tables, tyes, buddles, dolly-tubs, etc., etc. The method of dressing followed in the main the lines of English practice, but with many modifications, both in the machinery and the methods of working, due to the inventive genius of Mr. Parsons. Different forms of crushing apparatus were tried, and the best method of handling the ore and the different products of

Jan 1, 1889

By T. P. Chen, F. W. Bowdish

Studies made with a captive bubble apparatus on the sulfidization and collection by amyl xanthate of true chrysocolla specimens have defined the ranges of pH value and sulfide concentration which permit contact between the bubble and the mineral surface. Titanium compounds were the most effective of the materials found to activate the sulfidization of chrysocolla. With titanium activation, the contact angles and the ranges of pH value and sulfide wncentration giving bubble contact were all increased. Chrysocolla ores were concentrated by flotation. Chrysocolla ores occur at many localities in grade and quantity sufficient to make mining and millin feasible, but no satisfactory method of concentratio has been found. Although chrysocolla may be leached with acid, only those ores without acid-consuming gangue may be leached economically. Because of its potential importance, a study of the conditions nece sary for flotation of chrysocolla has been carried ou The literature contains a few references to flotation of chrysocolla. Two methods were developed by the U. S. Bureau of Mines.1,2 The first consisted of a fatty acid soap and a high xanthate as collectors of chrysocolla from a synthetic ore, while the second involved the use of hydrogen sulfide and xanthate. Ludt and DeWitt3 demonstrated the difference in adsorptive powers of chrysocolla and quartz for bas triphenyl methane dyes and suggested the use of butyl, hexyl or octyl-substituted malachite green as collector. Jackel4 emphasized the effects of combin tions of reagents such as Aerofloat 31, pine oil, and Reagents 404 and 425 with sodium sulfide and zinc hydrosulfite as conditioning agents. Although he reported recoveries of 89% from a synthetic ore and 98% from a natural ore containing azurite, malachite, chalcopyrite and chrysocolla, careful application of Jackel's method to chrysocolla from Tyrone, N.M., failed to give a high recovery. MATERIALS AND TECHNIQUE Samples from Inspiration, Ariz., and Tyrone and Magdalena, N. M., were used for experimentation and verified as true chrysocolla by leaching tests, specific gravity tests and X-ray diffraction. Chrysocolla does not dissolve at pH 4, although malachite and azurite do. Chrysocolla is about half as dense as the copper carbonates. X-ray diffraction analyses by the powder camera method confirmed the samples as true chrysocolla. A captive bubble apparatus, which cast an enlarged image of the air bubble and the mineral surface upon a screen, was used to check on the character of the surfaces. The specimens were prepared by grinding a flat surface on a glass plate using fine abrasive; then they were washed and kept in distilled water until they were to be treated with reagents. Before each reagent treatment, the specimen was carefully checked for cleanliness in the captive bubble apparatus. It was assumed that the surface was clean if, after fine grinding and washing of the specimen, the bubble would not stick. Specimens were handled with glass forceps, and precautions were taken to avoid contamination of the mineral surfaces. Contact angle measurements were carefully made several times on each treated specimen to obtain reliable average values. EFFECT OF pH VALUE AND SODIUM SULFIDE CONCENTRATION In each experiment, a specimen with a freshly ground surface was immersed for 10 min in a solution of sodium sulfide, washed and immersed for 15 min in a solution containing 30 mg per 1 of potassium amyl xanthate. The specimen was then washed again in distilled water and tested for contact angle in the captive bubble apparatus while submerged in distilled water. In this series of experiments, the pH of the sulfidizing solution was varied from 3 to 7, and the concentration of sodium sulfide, containing 60% Na2S, was varied from 50 to 650 mg per 1. Many combinations of pH value and sulfide concentration resulted in no contact between the bubble and the surface, but over a limited range of conditions, contact angles varying from 24ºto 52ºwere obtained. The data in Fig. 1 show sulfidization conditions that lead to bubble contact and those that do not. The region of contact is surprisingly small, which may indicate why flotation of chrysocolla involving sulfidization has proven so difficult in practice. Several features of the system are illustrated in Fig. 1. In the region between pH values of 4 and 6 with sodium sulfide concentrations below about 350

Jan 1, 1963

By C. E. Kemp, A. B. Dyes

Results of a field research project on the thermal recovery of oil by movement of a combustion front are presented. This field test was conducted in the South Belridge field, This The war paitern was a Southsing1e 2.5-acre five-spot pattern in the 700-ft deep Tulare sand. Results of this project indicate the technical feasibility of producing high viscosity, low-grallity crude oils by thermal means. It was demonstrated that heavy oils could be moved rapidly over considerable distances by thermal drive, and that high percentage recoveries of oil could be effected. The bulk of the oil recovery came after arrival of the burning front at a production well. However, rapid corrosion and high-temperature failure of conventional pipe and equipment both below and above surface occurred. Stainless steels gave more satisfectory performance under these conditions than did conventional steels. Oxygen was seldom observed in gas from wells ahead of the burning front, and it appears that the front was continuous throughout the life of the experiment. INTRODUCTION During late 1953 and early 1954, industry-wide attention was focused on the thermal recovery of oil by movement of a combustion front through an oil zone. Two separate Oklahoma field tests were described in publications by Kuhn and Koch, and Grant and Szasz. To obtain basic information needed for making engineering and economic appraisals of commercial recovery of heavy oil by this thermal recovery method, a new field research projecta3,4 was started May 31, 1955. Twelve oil companies contributed to this project with General Petroleum Corp. as operator. Since combustion recovery experiments* with heavy oils in other areas had been conducted in small patterns,"' an important purpose of this test was to determine whether the process could be operated in a pattern of near-commercial well spacing. The south Belridge field, located 30 miles north of Taft, Calif., was chosen because its oil sands are similar to many heavy oil sands which typically have low primary recovery and leave a large amount of oil in place. such fields are not particularly suited for common secondary recovery methods. DESCRIPTION OF TEST SITE The test interval was a Tulare sand at a depth of about 700 ft. Nine test wells were drilled, cored and completed from Oct., 1955, through Jan., 1956. The initial pattern shown on the map, Fig. 1, consisted of an injection well (II)', four producing wells (1P-4P), and four observation wells (IT-4T). An old well (81) was also recompleted for use as an observation well. The area enclosed by the original four production wells was 2.5 acres; the distance from the injection well to each production well was 233 ft. During the combustion period, Well 5P was drilled to replace Well 2P, and Well 6P was drilled to replace Well 3P. The new wells were 25 ft beyond the old production wells along a diagonal from the injection well, and resulted in an increase in pattern area to 2.75 acres. Isopachs are shown in Fig. 1. The average thickness of the oil sand in the test pattern was 30 ft. Fig. 2 presents two cross sections through the test pattern. Oil sand is represented by white and claystone by gray. The dashed lines indicate layers of conglomerate grading to claystone. The sand thickness was fairly uniform throughout the test pattern except in the 1P area. The sand body dips gently from the northwest to southeast, about 3 degrees from horizontal. The sand is unconsoli-dated, and grades from very fine material to pebbles as large as 2 in. in diameter. Table 1 presents the average initial properties of the formation. The in-place porosity of 37 per cent was estimated from the porosity of coke-consolidated cores taken after combustion. Original core analyses data were adjusted to 37 per cent, giving pore volume saturations of 60 per cent oil, 37 per cent water, and 3 per

The Institute assembled in the rooms of the Geographical Society, Cooper Union, at 8 o'clock P.M., February Nth, 1874. President Barnard, of Columbia College, delivered an address of Welcome, to which President Raymond responded. The Council then presented the following names, duly indorsed for election as members and associates. The gentlemen named were unanimously elected. *Bullock, M. C.,. ., . New York. Burke, M. D.,.... Cincinnati, Ohio. *Burt, M. W.,.....Wheeling, W. Va. Cameron, J. G. M.,. ..'New York. *Canfield, Frederick A,,. .. Dover, N. J. *Chandler, Prof. C. F.,. .. New York. *Clayton, J. E.,. .. . Salt Lake City. Colton, C. A,,.... New York. *Cooke, Prof. George H.,. . New Brunswick, N. J. *Cooper, Edward,.... New York. "Dahlgren, C. B.,.... Mazatlan, Mexico. Dutton, Capt. U. E.,. .. Washington, D. C. *Eurich, E. F.,.... New York. Fuller, H. L.,.... Woodside, Luzerne County, Pa. Hamilton, S. Jr.,.....New York: Harnickell, A,,.,.. New York. *Hearne, F. J.,. .. . Wheeling, W. Va. *Hill, Samuel W.,.... Marshall, Mich. *Hulbert, Edward J.,. . Houghton, Mich. *Hunt, R. W.,.....Troy, N. Y. Ihlseng, M.,.....New York. "Iselin, Henri,.... New York. *Janney, Morris P.,. ..Pottstown, Pa. "Jenney, Frank B.,. .. . Brooklyn, N. Y. *Jenney, Walter P.,... Brooklyn, N. Y. Joy, D. A.,.....New York. *King, Clarence,.... New York. *Kittoe, E. F.,....Charleston, S. C. Lawrence, Robert,.... New York. *Locke, J. M.,..... Cincinnati, Ohio. *McCormick, Henry,. .. Harrisburg, Pa.

Iron Ore Resources of the World (Die Eisenersvorrate der Welt)_ By G. Einicke. Verlag Stahleisen, Dusseldorf, 1950. 418 p., with 192 tables and an atlas volume containing 100 p. of reaps. 66 German Marks.-A notable work in which the latest available information on iron ore deposits has been compiled by diligent work, continent by continent, country by country. The author reveals the effect of geological formations, iron content of ore, accessability, cost of transportation, political and economic considerations. Ore beds of importance to the German iron and steel industry are given more space than others. The bibliography contains almost 250 references. A tragic comic feature is the author's complaint that as soon as a map of iron ore resources of a country has been completed, the country's boundaries are changed. Reviewed by W. Trinks, Carnegie Institute of Technology. Industrial Research Laboratories of the United States. National Research Council, Washington, D. C. Ninth Edition. 1950. 445 p. $5.-Contains information on the research laboratories of 2845 industrial and commercial organizations, including names of research executives, location of labs, types of activity, whether any consulting services are offered. There are two appendices, one of which lists data on government labo ratories which cooperate with industry, and the :)ibex naming universities and colleges offering research services to industry.

Jan 2, 1951

THE Institute assembled in the rooms of the Geographical Society, Cooper Union, at 8 o'clock P.M., February 24th, 1874. President Barnard, of Columbia College, delivered an address of welcome, to which President Raymond responded. The Council then presented the following names, duly indorsed for election as members and associates. The gentlemen named were unanimously elected. *Bullock, M. C., - New York. †Burke, M. D., - Cincinnati, Ohio. *Burt, M. W., -Wheeling, W. Va. †Cameron, J. G. M., - New York. *Canfleld, Frederick A., - Dover, N. J. *Chandler, Prof. C. F., - New York. *Clayton, J. E., - Salt Lake City. †Colton, C. A., - New York. *Cooke, Prof. George H., - New Brunswick, N. J. *Cooper, Edward, - New York. *Dahlgren, C. B., - Mazatlan, Mexico. †Dutton, Capt. C. E., - Washington, D. C. *Eurich, E. F., - New York. †Fuller, H. L., - Woodside, Luzerne County, Pa. †Hamilton, S. Jr., - New York †Harnickell, A., - New York. *Hearne, F. J., - Wheeling, W. Va. *Hill, Samuel W., - Marshall, Mich. *Hulbert, Edward J., - Houghton, Mich. *Hunt, R. W., - Troy, N. Y. †lhlseng, M., - New York. *Iselin, Henri, - New York. *Janney, Morris P., - Pottstown, Pa. *Jenney, Frank B., - Brooklyn, N. Y. *Jenney, Walter P., - Brooklyn, N. Y. †Joy, D. A., - New York. *King, Clarence, - New York. *Kittoe, E. F., - Charleston, S. C. †Lawrence, Robert,. - New York. *Locke, J. M., - Cincinnati, Ohio. *McCormick, Henry, - Harrisburg, Pa. * Members. † Associates.

Jan 1, 1874

By F. F. Aplan, G. Simkovich

Zinc oxide, an n-type semiconductor, and nickel oxide, a p-type semiconductor, were studied in electrostatic separation experiments in pure and doped forms. In addition, pure potassium chloride and potassium chloride containing one volume per cent silver were also investigated. It was found, in agreement with theory, that the presence of dopants in the oxides could either increase or decrease the electrical conductivity of the base compounds and, thus, control the response of these particles to electrostatic separation. Further, it was shown that the same dopant in the n- and p-type semiconductors produced opposite conductivity effects; again in accord with theory. Finally, it was found that the presence of dispersed silver particles in the normally insulator phase potassium chloride produced sufficient electronic conductivity to cause the silver containing particles to respond as would materials possessing "medium-type" conductivities.

Jan 1, 1980

By James B. Cathcart

Marine phosphorite deposits occur in Braxil, in the Bambui Group of late Precambrian or Early Cambrian age. The phosphorite is laminated, isoclinally folded, and is composed of black, elongated apatite pellets and quartz grains cemented by quartz and muscovite. Abundant, narrow quartz veinlets cut through the .rock at right angles to the elongation direction of the pellets. The phosphorite is 0 to 80 m thick and contains 5 to 30 percent P2O5. The deposit is elongate towards the northeast, and the central, thickest, and richest part is bounded by faults. Measured reserves are about 250 million tons that average a bout 13 % P205. Preliminary testing indicates that grinding, scrubbing, and desliming will produce a material usable for fertilizer manufacture at a cost competitive with imported phosphate fertilizers.

Jan 1, 1979

By Thomas M. Plouf

Getting optimal performance from flotation cells can, in many cases, be critical to a project's economic viability. Simple testing procedures can sound early warning signals as well as maintain optimum recoveries from the flotation cycle. The materials required for a simple testing laboratory include: (1) pH meter or pH paper, (2) bottles of reagents used in plant flotation, (3) stop watch, (4) calibrated eye droppers. (5) laboratory flotation machine (1000-g tank, open impeller), (6) froth collection pans, (7) magnifying glass, (8) sizing screen sufficient to retain 10% of the flotation feed coarse fraction, (9) sizing screen for the size particles at which desliming of the plant flotation feed is to take place, and (10) a set of screens covering the complete range of feed particle size.

Jan 4, 1978

By Robert E. Bush, E. S. Mardock

The objective of this paper is to present practical methods of applying radioactivity logs to problems of interest both to those engaged in evaluating fundamental reservoir data as well as to those engaged in subsurface structural work. The basic theories underlying the operation of radioactivity logging methods are briefly discussed along with some of the problems arising in the interpretation of the log. Relative methods of quantitative interpretation are described, with a discussion of relative reference lines and specific examples are given showing the application of these relative quantitative interpretation methods. To show the variation of the methods described, specimen wells penetrating formations widely divergent in point of geologic age were selected to demonstrate the application. A relative reference line is determined for the Neutron Curve and by comparison to known petrophysical data such as porosities from diamond cores, a direct quantitative relationship is developed. The application of this relative calibration curve to logs of unknown wells will permit a reasonably accurate determination of porosity in limestone and dolomite formations. Specific examples are given showing the application of these relative methods of interpretation to logs of the Smackover limestone in Louisiana, the Edwards limestone and dolomites of South Texas, and Permian dolomites of West Texas. Radioactivity logs have been used extensively by the petroleum industry for a number of years and recognition of their value has grown steadily, not only as tools to aid in the solution of specific stratigraphic problems, but also as potential sources of the basic data necessary for the estimation of net pay and reserves. The value of radioactivity logs for stratigraphic work has been pointed out in the literature,1,2,4,5,6 and now has long been recognized by the industry, but the quantitative application of the logs has advanced but little beyond the stage of a strong conviction that radioactivity logging curves will some day provide the information on such important quantities as the porosity and the liquid saturation of the formations. During the past few years the staffs of the Lane-Wells Company and Well Surveys, Incorporated, have devoted a great deal of time, thought, and experimentation to the relationships existing between radioactivity curves and the lithologic conditions encountered, and this paper is, in a manner of' speaking, intended as a progress report of this work and includes suggestions which the authors have found useful in the interpretation of radioactivity logs. The section on theory is not intended as a complete exposition of the physical processes involved, but rather as a brief introduction to the reader of these processes so that he may acquire a better understanding of the behavior of the radioactivity curves under the varied conditions encountered in normal well logging. Three relative methods for using neutron logs for the quantitative estimation of porosity in limestone or dolomite are presented. These methods are based on the comparison of logs and porosity data from wells in Louisiana, South Texas, West Texas, and New Mexico. These areas were selected because not only were there more core data available from these areas but also the majority of these data were from limestone or dolomitic zones. The correlation between core data and logs is simpler for limestones and dolomites than it is for sandstones due to the fact that sandstones are more complex than limestones and differ more widely among themselves as to composition of cementing materials, siltiness, etc. When data applicable to the various types of sandstones are available, the authors hope to present a discussion similar to this paper covering sandstones or possibly a more general discussion covering all types of reservoir rocks. The relative methods for estimating porosity which are presented in this paper fall short of the absolute method sought. However, these methods possess the advantage that they can be applied to almost any neutron log as long as the range of application is held within the limits imposed by the local lithologic conditions which prevailed during calibration, i.e., these methods are for short range application only. THE THEORETICAL BASIS FOR RADIOACTIVITY LOGGING The two redioactivity logging curves commercially available today are the

Jan 1, 1950

By William P. Blake

The literature of the occurrence of quicksilver-ore in the United States does not contain, so far as the writer is aware, any mention of the locality herein described. In the preliminary report * upon the resources of the transPecos region of Texas, von Streerwitz gives a long list of minerals observed as occurring there, but cinnabar is not mentioned. In the second report upon the same region † mention is made of the reported existence of cinnabarite in one of the mountain ranges north of the Sierra Carrizo and the Bofecillos, but the author adds: " In spite of my careful examination of the float, I have not yet found any traces of this metal (quicksilver) up to the present time." Prof. Dumble, also, in * Geol. Surv. of Texas, E. T. Dumble, 1889, p. 225 (first report). † Geol. Surv. of Texas, E. T. Dumble, 1890, p. 713 (second report)

Jan 1, 1896

By B. F. Tillson

ALTHOUGH most accidents occur through the A carelessness or misfortune of the workmen; that is no reason why we should not take all physical precautions practicable. The best way to approach the problem of mine safety is to acquire a personal feeling of responsibility for the accident and then plan how it might have been prevented had we known that it was to occur. A statistical analysis of the physical conditions contributory to accidents will give an indication of some of the methods or mechanisms that should be revised or safeguarded. The handling of rock or ore is a common source of minor injuries. Freedom from accident when mucking largely depends on the skill and care of the workman; this also is true, to a certain degree, to loading cars from chutes, but much can be done in the layout of chutes and their equipment to provide equal safety with less skill. Permanent stagings, or rigid units that may be easily assembled, should be provided so that the men handling the chute boards or gates and barring the jammed chunks will have a convenient safe footing for their operations. A stance to the side of the chute mouth is to one in front, because a man will not be liable to be struck by flying lumps or his bar, should it he caught in the mass, yet in many mines the workmen face the chute when loading a car. Fig. 1 shows the operation of a plank chute having special latches which support the chute boards in such manner that they may be conveniently dropped into place to stop the flow of ore.

Jan 1, 1926

By E. M. Norris

THE Western phosphate deposits extend over a large area in the Rocky Mountain region, comprising portions of south central Montana, southeastern Idaho, northeastern Utah, and southwestern Wyoming. A limited acreage of these deposits passed into private ownership prior to Dec. 9, 1908, at which time 7000 sq. mi. of land in these phosphate fields was withdrawn from public entry by direction of the Secretary of the Interior. Under the Act of Feb. 25, 1920 (41 Stat. 437) title to all phosphate lands in the public domain was reserved to the United States with provisions for leasing portions to citizens, corporations, states, etc. The above act, in effect, created by law a Western phosphate reserve of approximately 2,269,055 acres.

Jan 1, 1944