Search Documents

By D. B. Dowling

The interest which has been aroused in prospecting for oil in the foothills of southern Alberta, and in the oil possibilities of the known gas fields situated in the less-disturbed areas, called for a much closer examination of the structure, thickness, and composition of the underlying rocks of the region than had hitherto been made. The areal geology of the larger part of the great plains was outlined by Dawson, McConnell, and Tyrrell, between 1881 and 1885. The foothill area was not critically examined at that time, owing to the time which would have been required for its proper study and the difficulty that was found in recognizing in the foothills the divisions which had been adopted in the mapping of the formations of the plains. This was due in great measure to the paucity of exposures in continuous sections of the lower divisions of the Upper Cretaceous. Since the pioneer work on the plains was published, the beds which form continuations south into Montana have been critically examined, The Canadian beds arch over the end of a flat anticline which rises to the south; and two sections in Montana, one on each side of the anticline, help to explain some of the difficulties previously encountered in the mapping of the measures found in the foothills. The index map, Fig. 1, shows the area studied, and its relation to southeastern Alberta, and to Montana. Problems of Correlation The principal difficulty experienced in correlation was in connection with the measures known as the Montana group. The beds of this group did not seem to agree in the two Montana sections. They showed the same differences to some extent as are encountered in comparing the foothill measures with those of the plains. The Montana group in Dakota and Manitoba consists of a series of shales of marine origin. In the eastern Montana section two sandstone members appear, leaving a shale member at the top and another

Jan 1, 1916

By Fred T. Greene

Most of the recent discussion of the mineral land law published in the Transactions is in the abstract—an exception being Mr. Goodale's paper, The Apex Law in the Drumlummon Controversyll which illustrates in concrete instances many of the practical disadvantages of what Dr. Raymond has called "The Law of the Apex." The present paper, it is hoped, may serve a similar purpose, emphasizing the necessity for a change in our mining laws, and bringing home to mining engineers some of the defects and dangers of our present code. There are many storm centers of "apex litigation" in the Rocky Mountains; and not the 1east. of them is the Wardner camp, where such litigation has been almost continuous since 1892, and the end is not yet. In their decisions, the courts have accepted the claims of the litigants that the "Wardner vein" is a broad zone varying from 250 to 500 ft. in width at the surface. This is the simplest theory which could have been advanced, and probably decreased, rather than augmented, the number of contests; in fact, every one of the claim owners seemed to feel that the greatest advantage would accrue to him if this theory were adhered to. The dominant structural feature of the Wardner vein is a persistent fault, striking N. 40' W., dipping about 40" to the southwest and called the "Wardner foot wall." Fig. 1 is a composite of two adjacent cross-sections of the vein and is a fair representation of the relative size and shape of the orebodies and their relation to the "Wardner foot wall." The country rock is a comparatively thin-bedded sericitic quartzite which has an average strike of N. 80" W. and dips at high angles to the north and south. The movement on the Wardner foot wall is apparently normal, and there has been more or less brecciation on either side of it; but as the moving mass was that above the foot wall, the brecciation has been more complete on that side, and has extended farther from the plane of movement. Many minor faults, generally of insignificant extent, resulted from the movement along the Wardner foot wall. Most of these were

Jan 1, 1916

By Frederick J. Pope

The protaxis of the North American continent consists, as is well known, of a large V-shaped area of Archæan rocks, which lie for the most part in the Dominion of Canada, and occupy an area of not less than 2,031,000 square miles. The western limit of this area extends from 'Lake Superior in a northwesterly direction to the Arctic Ocean, the southern is found along the Lower St. Lawrence as far as Labrador. A minor area, spoken of as the Adirondack region of northern New York, has a somewhat broken connection with the main body in a narrow band of igneous rock, which crosses the Upper St. Lawrence where it leaves Lake Ontario. The ancient crystallines are also presumably beneath all the later sediments, hut the above brief description outlines their principal exposures. This great rock-complex consists, for the most part, of a series of gneisses, which present great variations in both structure and composition. In certain sections areas of gneisses of the general composition of granite, and remarkably uniform in character, prevail. They consist largely, if not exclusively, of crystalline rocks in which a banding or foliation has been induced by pressure. These rocks constitute the basal member of the Laurentian system, and by later writers have been referred to as the Ottawa gneiss. In other and quite extended areas, gneisses, regarded by many as composed of altered sediments, are associated with crystalline limestones, quartzites, and much injected igneous matter. To this series the term Grenville has been applied. Both of these series of gneisses are penetrated by various igneous masses, of which the most important are great intrusioiis of several members of the gabbro family, such as anortho-sites, norites, pyroxenites, and gabbros proper; the whole form-

Jan 1, 1900

By S. F. Shaw

The Sierra Mojada mining district is situated in western Coahuila, about 8 km. east of the Chihuahua state line, and about one-half way from the northern to the southern extremity of the state. It is at the terminus of the Mexican Northern R. R., 125 km. northeast of Escal6n, Chihuahua; also about, 240 km. due west of Monclova, Coahuila. The altitude is approximately 1500 m. above sea level. The Sierra Mojada valley is about 10 km. long, from east to west, with a width of 1 to 2 km. It is approached from the east through the Puerto del Oro, where the Mexican Northern R. R. enters the valley; the slope from west to east is gentle. The Sierra Mojada, of which about 300 m. is an almost vertical wall, bounds the valley on the south side; on the north side, the slope to the crest of Sierra Planchada is more gradual, rising only 200 or 300 m. above the valley. Water is relatively scarce in the district, and there are no running streams. The rainy season, usually beginning at the middle of June, lasts through July, and occasionally into August or September. In some years the rains fail entirely. The slope of the ground is such that nearly all the water immediately runs off. The arroyos along the flanks of the mountains are not very deep, but in heavy rains, sometimes approaching cloudbursts, a tremendous volume of water rushes down them, carrying large boulders. A certain amount of seepage collects in the agglomerate, lying below the conglomerate, and is retained in the local fractures. Some shallow wells have been sunk in this agglomerate, and one well over 150 m. deep was sunk on the Volcan ranch, supplying about 76 1. (20 gal.) per min. A considerable supply of water is collected in large earth reservoirs in and below the town of Esmeralda. In ordinary years this supply will last until January or February, after which the Volcan well has to be depended on until the next rainy season. Vegetation is scarce, aside from scanty scrub oak and other brush in the mountains, and a few mezquite, locust, pepper, and cottonwood trees

Jan 1, 1923

By S. F. Shaw

The Sierra Mojada mining district is situated in western Coahuila, about 8 km. east of the Chihuahua state line, and about one-half way from the northern to the southern extremity of the state. It is at the terminus of the Mexican Northern R. R., 125 km. northeast of Escal6n, Chihuahua; also about, 240 km. due west of Monclova, Coahuila. The altitude is approximately 1500 m. above sea level. The Sierra Mojada valley is about 10 km. long, from east to west, with a width of 1 to 2 km. It is approached from the east through the Puerto del Oro, where the Mexican Northern R. R. enters the valley; the slope from west to east is gentle. The Sierra Mojada, of which about 300 m. is an almost vertical wall, bounds the valley on the south side; on the north side, the slope to the crest of Sierra Planchada is more gradual, rising only 200 or 300 m. above the valley. Water is relatively scarce in the district, and there are no running streams. The rainy season, usually beginning at the middle of June, lasts through July, and occasionally into August or September. In some years the rains fail entirely. The slope of the ground is such that nearly all the water immediately runs off. The arroyos along the flanks of the mountains are not very deep, but in heavy rains, sometimes approaching cloudbursts, a tremendous volume of water rushes down them, carrying large boulders. A certain amount of seepage collects in the agglomerate, lying below the conglomerate, and is retained in the local fractures. Some shallow wells have been sunk in this agglomerate, and one well over 150 m. deep was sunk on the Volcan ranch, supplying about 76 1. (20 gal.) per min. A considerable supply of water is collected in large earth reservoirs in and below the town of Esmeralda. In ordinary years this supply will last until January or February, after which the Volcan well has to be depended on until the next rainy season. Vegetation is scarce, aside from scanty scrub oak and other brush in the mountains, and a few mezquite, locust, pepper, and cottonwood trees

Jan 1, 1923

By A. Perry Thompson

I- GeneRal Distribution, AppeaRance, and Relations ........ 563 11. Data fRom MicRoscopic Examination............... 568 1. Criteria for Distinguishing Primary from Secondary Minerals...... 568 2. The Leonard Vein Filling..................... 574 Quartz............................ 575 Pyrite............................ 575 Enargite............................ 576 Covellite............................ 578 Bornite............................ 581 Chalcocite........................... 583 Chalcopyrite.......................... 586 3. The Fault-Vein Covellite..................... 587 The Speculator Ore........................ 587 The East Gray Rock Ore.....,.............. 589 4. Other Occurrences of Covellite.................. 591 111. Conclusions........................... 592 1. The Replacement of Minerals..................592 2. The Character of Mineralizing Solutions .............. 594 I. General Distribution, Appearance, and Relations Mining in Butte has seldom encountered covellite in commercial quantities. The notable occurrences, extending vertically and laterally perhaps several hundred feet, presented scattered, bladed lenses of this mineral in a matrix of quartz, pyrite, enargite, bornite, and chalcocite. But under the microscope covellite is seen to be widespread in the Butte ores, though in such small quantity that megascopic examination will not discover it. In early mining operations covellite was found in the Gray Rock vein, a member of the Blue vein system. As described by Sales,' it persisted as an occasional ore mineral, associated with quartz, pyrite, tetrahedrite, bornite, chalcocite, and minor amounts of sphalerite, from the 700-ft. to the 1,200-ft. level of the East Gray Rock and Diamond mines. Crushed quartz-monzonite and later quartz completed the vein filling between

Jan 1, 1916

By W. S. Hyler, L. W. Berger, R. I. Jaffee

Hydrogen additions of 390 ppm to A-55 titanium and 368 ppm to Ti-8 pet Mn have no deleterious Hydrogenadditionseffect on the unnotched and notched rotating-beam fatigue properties of these materials. 'These amounts of hydrogen, however, are sufficient to cause severe notch-impact thesematerials.embrittlement in A-55 titanium and pronounced loss of tensile ductility in Ti-8 pet Mn. The lack of embrittling effect in fatigue in the latter alloy is consistent with the postulated strain-aging mechanism of hydrogen embrittlement in a-ß alloys. There is a significant strain-agingincrease in the unnotched endurance limit of A-55 titanium with the addition of hydrogen. This increase may be explained as the result of internal heating effects which would dissolve the hydride and cause solid-solution strengthening. TITANIUM and its alloys may be seriously embrittled by relatively small amounts of hydrogen. The form which this embrittlement takes has been shown to vary with alloy type. The a alloys, for example, suffer most strongly from loss of notch-bend impact toughness' when sufficient hydrogen is added, and this effect has generally been associated with the presence of hydride phase in the micro-structure. In a-ß alloys, on the other hand, hydrogen is most detrimental to tensile ductility in slow-speed tests,2-1 and the embrittlement may be detected in a most convincing manner by means of rupture tests at room temperature. This particular kind of embrittlement has not been associated with a change in microstructure, but has been classified rather generally as associated with a strain-aging type of mechanism.' In the present paper, the effect of an embrittling amount of hydrogen on the rotating-beam fatigue properties of both an a and an a-ß titanium alloy is covered. For this study, annealed commercially pure (A-55) titanium was chosen as an a alloy, and equilibrated and stabilized Ti-8 pet Mn as representative of a typical a-ß alloy. Nominal hydrogen levels of 20 and 400 ppm were evaluated, the latter amount having been shown previously to be severely detrimental to the impact toughness of commercially pure titanium and to cause pronounced strain-aging embrittlement in the Ti-8 pet Mn alloy. The only report of the effect of hydrogen on the fatigue properties of titanium is given by Anderson et al.,° in which a push-pull type of fatigue test was conducted on as-received commercial-purity titanium sheet. Much scatter was found in the results, but generally the presence of hydrides slightly decreased the fatigue strength of unnotched specimens in the longitudinal direction. The results of notched tests were masked too greatly by scatter to be significant. Experimental Procedure Preparation of Materials—Analyses of the A-55 titanium and the Ti-8 pet Mn alloy used in this investigation are given in Table I, which indicates the 8 pet Mn alloy to be more nearly a 6 pet Mn alloy. This alloy will be referred to as Ti-8 pet Mn, however, since this is the commercially designated composition. Both alloys were received in the form of5/8-in. diam rod and, after suitable surface preparation, 5-in. lengths were vacuum annealed at 820°C. Half of the rods for each material were then hydrogenated at 820°C to a nominal hydrogen content of 400 ppm. The hydrogenated and vacuum-annealed A-55 rods were hot swaged at 700°C from 5/8-in. diam to 1/4-in. diam, and then annealed 1 hr at 800°C and air cooled prior to preparation into test specimens. Fabrication of the Ti-8 pet Mn alloy was by hot swaging to 3/8-in. diam at 760" and then 1/4-in. diam at 704°C. This material was then annealed 1 hr at 704", followed by furnace cooling to 593"C, and finally air cooling to room temperature. Evaluation—In order to examine more completely the effects of hydrogen on the particular materials studied, slow-speed tensile and notch-bend impact properties were determined in addition to fatigue data. Tensile specimens were of the standard ASTM type with a reduced section of 1/8-in. diam and a gage length of 1/2 in. A subsize cylindrical Izod specimen was used for impact tests. These specimens had a 45" notch with a 0.005-in. radius and a 0.150-in. root diam, and the stress concentration factor of this notch in bending was Kr = 3. Both the ten-

Jan 1, 1959

By THOMAS S. MENNIE

ON GORE Mountain, about four and a half miles, southwest of the village of North Creek, Warren Co., N. Y., are the Barton Mines. Here is the largest known deposit of garnet in the world. This property is owned by H. H. Barton &: Son Co., of Philadelphia, and is being worked under lease by Barton Mines Corpn. North Creek is the terminus of the branch of the Delaware and Hudson R..R., which runs into the

Jan 1, 1925

By AIME AIME

THE 140th meeting of the Institute will be held in the Engineering societies Building, 'New York, Feb.: 16-19, and one of the most important features, one which cannot be reduced to text in the TRANSACTIONS, will be the opportunity to renew old friendships and make new friends, to talk things over -to orient one's self in these troublous .times. There will be daily get-together luncheons for all, luncheons and dinners for specialized groups, an informal dance, the annual reception and banquet, and a smoker. And such a smoker! It starts with dinner at .dinnertime, shows signs of cabaret, turns smoker, and then goes entertainment-all for the price of one. This year one can stay long after 11 o'clock-there will be time and opportunity to amble around and meet everyone present. The formal program is rapidly rounding into shape. The annual business meeting will -be held on Tuesday morning and the banquet will be at the Commodore. The four Divisions and the various, Technical Committees are arranging their sessions. and scheduling for these a long list of significant papers. A .feature of the meeting will be a number of round tables on timely subjects.

Jan 1, 1931

.MAX ROESLER, Firmeza, Oriente, Cuba (communication to the Secretary?).-It is substantially admitted by all who have recently been in touch with these deposits that the orebodies lie in the fine-grained dark-green rocks, called diorite by most writers and diabasic by myself. The three points of disagreement concern the agency of included limestone blocks as causes of deposition, the agency of the

Jan 5, 1917

W. E., RUDER, Schenectady, N. Y. (written discussion *).-Professor Howe, with characteristic thoroughness, has demonstrated that Professor Jeffries' "Reversed Inheritance" explanation of the case in question is contrary to fact, as shown by many previous observers. Since the photographs were my own, I feel it my duty to say a few words in discussion. In the first place, it is to be noted that these photographs were of pressed powders, and although many of Professor Jeffries' original experiments were made from this kind of material, the nature of such a specimen must of necessity be different from that of the fused metal, although the same basic laws of grain growth may apply in both cases, certain factors, such as the rate of change, for example, are undoubtedly different in each case. That the 1000° C. grain is a natal grain is evident from its appearance contrasted with the more perfectly formed, though smaller, grains in the 1300° C. photograph. I am not sure that Professor Howe's explanation of the formation of this grain is necessarily the correct one, although it agrees with. Stead and Carpenter's results. I am inclined to think that this grain may have been formed on heating, because I have been able to produce grains of the shape and magnitude of Stead and Carpenter's grains by heating to 850° C. pure electrolytic iron, which has been subjected to a strain gradient. On reheating to 1300° C., the mobility being so much greater, the individual crystals had time for unhampered re-arrangement and growth after their second refinement on passing Ac3, so that we have in this case a true fused metal condition in which the individual crystals are arranged in true equiaxed grains of a size consistent with their high temperature anneal. In this case the grains are equiaxed, inheriting none of the columnar tendencies of the previous grain, because they were not affected by any strain gradient, except possibly some accidental local gradients. It seems to me that the introduction of pressed powders into the discussion of grain growth, where allotropic changes take place, unnecessarily complicates an already complicated problem.

Jan 1, 1918

By D. J. Coolidge, H. L. Sheakley

THIS paper does not deal with all sands used in the glass industry in Missouri; it covers only that used in the plate-glass factory at Crystal City. However, it is probably safe to say that other sands, pro- [ ] duced throughout the state for this purpose, are of identical nature. The glass sand used in Missouri is commonly called the St. Peter deposit, which is ascribed to the Ordovician Rock series in the form of sandstone. This St. Peter deposit, aside from a few small outliers, covers a large area of eastern Missouri. It forms, through a broad curve, the northeast margin of the typical Ozark region between Cape Girardeau on the southeast and Mineola, Montgomery County, on the northwest. The belt is extremely irregular, varying from one to ten miles in width; its length is 150 miles in a straight line. [ ] The outcrop near the entrance to the Crystal City mine appears in the form of a sandstone bluff approximately 30 ft. high, running along Plattin Creek (Fig. , I). Above the sand rock an overburden of Joachim limestone appears, which, thickens to nearly 300 ft. and forms the hill commonly called Buck Knob. Test holes, where drilled at various points and the drillers' log indicate that the St. Peter deposit ranges in thickness from 63 to 71 feet. PROPERTIES OT THE ST. PETER SAND From an analysis of the glass sands of the St. Peter formation in Missouri, the follow-

Jan 1, 1942

By Arnold H. Kackman

At the Kaiser Cement and Gypsum plant near San Jose, Calif., one rod-ball mill has taken over the entire raw grinding function for the largest single cement operation in the West. Installed as part of a major overhaul performed on the plant by Kaiser Engineers, the new mill does the work of seven previous mills in feeding the plant's six kilns and keeping pace with its annual capacity of 8.5 million bbl of cement. Installation of the mill, which is the largest in the world, was started in December of 1966 and completed in April of 1967. The over-all modernization program surrounding the new mill has included the modification of existing crushing facilities; the building of new raw materials handling and blending facilities, new raw milling facilities, and new slurry handling facilities; and the installation of a digital-analog control system.

Jan 7, 1967

By C. E. Dobbin

THE identification of rock formations by a study of certain physical characteristics of burned samples was introduced in Wyoming in 1,926, when W. G. Buckles, superintendent. of the brick department of the Parco Development Co., reported to officials of the Producers & Refiners Corpn. that shales from the Cretaceous and older formations exposed between Parco and Rawlins exhibited distinctive coloration and textural features when burned in a standard brick kiln at temperatures ranging between 1000° and 3000° F. In collaboration with Elfred Beck, chief geologist of the Producers & Refiners Corpn., Buckles later burned cuttings and cores from several Wyoming wildcat wells in a standard kiln and successfully identified certain subsurface formations which had not been satisfactorily identified by other means. The results of their investigations were outlined in papers presented by Beck before the American Association of Petroleum Geologists at San Francisco in March, 1928, and by Buckles at. a joint meeting of the Rocky Mountain Oil and Gas Association and the Production Division of the American Petroleum Institute at Casper in November, 1928. These papers have not been published. The investigations set forth in this paper were carried out for. the purpose of determining the value of certain ceramic tests in assisting the petroleum engineers of the U. S. Geological Survey to identify well cuttings that represent Cretaceous shales penetrated beneath unconformable Tertiary formations in central, and eastern Wyoming, but that yield neither lithologic nor paleontologic criteria for satisfactory correlations with distinctive weathered outcrops. The investigations were made in the chemical laboratories of the Geological Survey at- Midwest, Wyo., and consisted of studying certain physical characteristics of burned bricks from representative outcrop samples of unweathered Cretaceous shales and of similarly burned cuttings of the same shales collected from wells in the Salt Creek oil field.

Jan 1, 1931

By W. L. Penberthy, H. J. Ramey

Experimental work on the combustion oil recovery process has consisted of both laboratory and field studies. Although field experiments are the ultimate test of any oil recovery process, they are costly, time consuming and difficult to analyze quantitatively. Laboratory combustion tube experiments can be opertzted far more rapidly and cheaply, but are subject to scaling and interpretation problems. This paper points out some important design problems, operational criteria and considerations in2portunt to interpretation of results. An analytical hcut model of movement of a burning front axiully along a cylinder with heat loss through an annular insulation was developed. The result was used to identify steady-state temperatrrre distributions both ahead of and behind the burning front, with and without heat loss. Results indicate potential operating limitations on the minimum burning front rielocity (or air flux) which may be used for any given combustion tube. Results also enable estimating the effective thermal diffusivity and over-all heat loss from experimental data and thickness of the brnning zone. Resu lts of operation of a combustion tube constructed recently verify this preliminary theory in the region immediately ahead of and behind the burning front surprisinRly well. INTRODUCTION Many field and laboratory studies of the forward combustion oil recovery process have been conducted since the early publications of Kuhn and Kochl and Grant and Szasz2 in 1953 and 1954. In view of the complex and costly nature of this type of investigation, it is not surprising that no complete theory of the nature of the forward combustion Drocess is yet available. However, gross effects are understood well enough that reasonable design procedures are available for planning field operations. Nelson and McNeil 3,4 have published two comprehensive papers concerning design procedures. One major consideration in planning field operations is the fuel concentration at the burning front. Fuel concentration controls air requirements — an important cost factor in forward combustion. Although fuel concentration can be estimated from field test results by various methods, results are subject to great uncertainty in view of natural limitations on experimental observations. Nelson and hlcNeil4 recommend that fuel concentration be determined from laboratory combustion tube studies. Fuel concentration is only one of many important factors which can be studied by combustion tube experimentation. An obvious goal of imporrance must be development of a comprehensive theory of the forward combustion process. If a theory of this process can be established which matches controlled laboratory experimentation, it should be possible to apply this theory to field operating conditions with some confidence. Laboratory combustion tube studies have already yielded important information concerning the combustion process. However, details concerning the design, construction and operation of combustion tubes are rare. Combustion tubes used by various investigators vary in size, length and mode of operation. Therefore, one purpose of this paper is to present considerations important to design, construction and operation of a combustion tube. In regard to previous combustion tube studies, attention is called to Refs. 1 through 9. These references describe a wide variety of equipment types and present a great deal of pertinent experimental data. In general, combustion tubes usually consist of thin-walled stainless steel tubes containing an oil sand pack mounted within a pressure jacket. Provisions have often been made to heat the tube ex tern a lly by separately controlled heaters to reduce heat losses. This step usually permits operation at low air fluxes (air rate per square foot burning front surface) similar to those encountered in field operations. Burning is usually conducted from the air inlet end of the tube to the outflow end. The tube orientation used has been vertical or horizontal. For vertical tubes, burning has been conducted vertically downwards. As a result of laboratory studies, many of the

Jan 1, 1967

By A. B. Young

THERE were produced in this country in 1923 probably in the neighborhood of 12,000 or 13,000 tons of refined and crude arsenic, by far the greater portion coming as a by product of smelting operations. Early this year copper smelters were producing arsenic at the rate of about 425 tons per month and lead smelters at the rate of 7;0 tons per month. During the entire eighteen years prior to 1919, there were produced in the United States only 47,000 tons of arsenic, which amounts to only 25 per cent. of the present output. The great increased demand has come about through the augmented use of arsenates as insecticides and arsenates as weed killers. In an extract from "Mineral Resources of the United States" on "Arsenic in 1922," Messrs. Heikes and Loughlin say, "The minimum possible demand for arsenic in 1923 was estimated at the end of 1922 to be about 13,000 tons, including 2000 tons for plate glass manufacturers, 3000 tons for lead arsenate, 3500 tons for calcium arsenate, 1500 tons for weed killers, 1200 tons for Paris green, 1000 tons for sheep dips and 750 tons for proprietary mixtures. More recent information, however, indicates twice as great a demand for calcium arsenate." The latter has found great use in the last three or four years as a weapon to combat the boll weevil pest of the southern cotton belt. ~t the present writing refined white arsenic is being quoted on the New York market at from 13)d c. to 1455 c. per Ib., while the average price during the eighteen-year period just mentioned was 4.8 c.

Jan 1, 1924

By C. Edwin Nighman

THE following is a description of the methods used in rescuing men and extinguishing the underground fire at the Pennsylvania mine, Butte, Mont. This fire, which cost the lives of 21 men, began about 9 p.m., Feb. 14, 1916, at or near a ventilating fan on the 1,200 air-shaft station. This shaft at that time was downcast, while the main hoisting shaft was upcast. Owing to the proximity of the fire to the air shaft, the air in the latter soon became heated, and as the fan on the level was not running¬the power having been cut off shortly after the outbreak' of the fire-the aim' shaft became upcast to the 300 level. At this point a blanket of cold air from the surface caused the smoke and gases to he drawn in on that level and carried down again through the workings to the 1,200. A short time after the discovery of the fire, water was turned down the air shaft through a series of pipes around the collar of the shaft, which caused the smoke to recede, below the 300, so that within 2 hr. it was possible to search that level for the missing men. From the above it will be apparent why the air shaft was upcast instead of downcast as under normal conditions, and why men were suffocated at considerable distances from the seat of the fire. The smoke and gases that came up the main hoisting shaft did not diffuse through the workings to any extent. There are doors on all levels in the connections to the main hoisting and air shafts, but-in the confusion and running around many of these doors were left open, and this undoubtedly caused the smoke and gases to spread more rapidly than they would otherwise have done. It was necessary for most of the men on the various levels to pass close to the air shaft in going to the hoisting shaft, and when they encountered the smoke and gases in that vicinity a number turned hack and climbed down with the direction of the air currents and were then suffocated, while all those who passed through the relatively short pall of smoke to the main shaft were saved.

Jan 2, 1917

By Charles Pack

Die castings may be defined as metal castings made by forcing molten metal, under pressure, into a metallic mold or die. It is necessary to keep this definition in mind to avoid confusing this process with other permanent-mold casting processes. The fundamental principles of the process have been known and practised many years. The simplest application is embodied in the modern linotype machine in which molten metal (usually tin-lead alloy) is forced under pressure into a metallic mold. The pressure is derived from a piston and cylinder immersed in the molten metal. Progress in the art of die casting may conveniently be divided into three groups: Machine for imparting pressure to the metal, material for the die or mold, casting alloys. The problem of delivering molten metal under pressure into a die is comparatively simple, when dealing with low-fusing-point alloys, as the alloys of lead and tin, but it is much more complicated when dealing with metals of higher fusing points, such as the alloys of zinc, aluminum, and copper. Although the art of die casting is comparatively new and, to a large extent, unknown, the records of the patent office are replete with patents on the subject. Fig. 1 shows the Underwood machine patented in 1902; this is probably one of the first machines designed for the production of commercial die castings. The relation of this machine to the linotype casting machine is clearly apparent. A cylinder and piston are immersed in the molten metal, the application of power to this piston forcing the molten metal, under pressure, into the mold or die. The Doehler machine, Fig. 2, patented in 1907, is based on the same general principles. This machine is used to a large extent at the present time, throughout the United States, for the production of zinc, tin, and lead alloy die castings. In the machine shown in Fig. 3, patented by Doehler in 1910, compressed air is used for forcing the metal into the die. In Fig. 4 is shown another of this type of machine. Here compressed air is applied to the surface of the molten metal to force it into the die. In a machine patented by Chandler in 1914, shown in Fig. 5, the

Jan 1, 1919

By D. R. Cook

This paper is a case history of an exploration venture for base metals, begun by the Rocky Mountain District of Bear Creek Mining Company in 1952 and completed in 1954. The project was based on the idea of W. S. Burbank, U. S. Geological Survey, that commercial deposits of base metals might occur in Paleozoic sediments beneath hydrothermally altered volcanic rocks in the Southern Bonanza mining district, Colorado. Here, an area of andesitic rocks, four square miles in extent, has been argillized, pyritized, chloritized and silicified. Geological, geophysical and geochemical studies were followed by the diamond drilling of three holes totalling 6,220 feet. Further alteration ang geochemical studies were made on the cores from these holes. A brief review of the alteration and geologic mapping, colored aerial photograph interpretation, geochemical soil and rock sampling, magnetic, gravity and radio-metric surveys are presented together with some conclusions regarding this work. This paper is a case history of an exploration venture for base metals, begun by the Rocky Mountain District of Bear Creek Mining Company in 1952 and completed in 1954. Important contributions were made to the project by personnel of the Rocky Mountain District and the Geophysics Division. Individual acknowledgements to these people are made at the end of the paper. BASIS FOR THE PROJECT The project was based on the idea of W. S. Burbank (1947, p. 444) that commercial deposits of base metals might occur in Paleozoic sediments beneath hydrothermally altered volcanic rocks in the Southern Bonanza mining district, Colorado. Paleozoic sedimentary rocks, including the favorable Leadville limestone, are exposed three miles south of the altered area, and reason exists to believe that they might underlie it within a reasonable depth. Alteration of pre-mineral volcanic rocks has been used successfully as a guide to concealed orebodies in the Main Tintic and East Tin tic mining districts, Utah (Bill-ingsley, 1933, p. 120-122; Lovering et al, 1949; Howd, 1957, p. 124-134; Cook, 1957, p. 73) and could be a useful guide here. GENERAL GEOLOGY AND STRUCTURE The Northern and Southern Bonanza mining districts are northwest of the San Luis Valley in southern Colorado, just within the northeastern edge of the San Juan volcanic province. The districts are1ocated on the southern extension of the Sawatch uplift, a prorninent northwest-trending structural high. The highly productive mining camp. of Leadville, Gilman and Aspen are on the northeastern and northwestern flanks of this uplift where Paleozoic limestones have

Jan 1, 1961

By Howard N. Eavenson

ALL of the matters so far taken up by the Institute Committee on Stabilization of the Coal Industry will be of help, but it seems to be that under present conditions not very much can be expected until the railroad situation has been improved. As an instance of this, I would cite the fact of our experience at our mines in West Virginia and Kentucky. During 1917 and 1918 at our West Virginia plants we produced for our own consumption, practically entirely in the Chicago district, about 4,750,000 net tons of coal. In 1919 our output was reduced to 3,500,000 tons, this being caused partly by the shortage of orders in the few months following the armistice, but more particularly by The car shortage which began last September and continued throughout the remainder of the year, with the exception of December. This car shortage has been more acute since the first of the year, and while we now have an actual capacity here of 20,000 tons daily and have the equipment to produce it, with the possible exception of a few houses, we are able to average only about 12,000 tons, and in consequence, about 30 per cent. of our by-product ovens in the Chicago district are idle, and a number of blast furnaces are down for the want of coke. These figures, of course, refer to conditions before the strike of switchmen in April was started.

Jan 1, 1920