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By W. Rostoker, R. P. Elliott

TWO intermediate phases enter into equilibrium with the primary solid solutions of titanium.' The TiMn2 phase was identified by Wallbaum2 as of the C14 type isomorphous with MgZn2. Contrary to Maykuth, et al.,¹ the phase occuring at about the 50-50 atomic proportion has been shown to derive from a peritectoid reaction.:' A 30 day anneal at 900°C of an alloy containing 52 wt pct Mn developed sufficient of the new phase to give a clear and predominant diffraction pattern. The powder pattern was taken in a 14 cm diameter powder camera using filtered Cu Ka radiation. In all, 75 lines were recognized and measured. Interplanar spacing and observed intensities for the first 26 of these are given in Table I.

Jan 1, 1954

By Fred R. Ingram

FOR the purpose of this discussion, let us consider that the Rocky Mountain region covers the area in the seven Mountain States, Idaho, Montana, Wyoming, Utah, Colorado, New Mexico, and Arizona, and before we discuss the needs of these states, let us define Industrial Hygiene. Industrial Hygiene is that branch of preventive medicine concerned with the protection of health, improvement of efficiency, and prolongation of life of the industrial worker; in short, adult health conservation. It includes in its broad meaning not only the prevention of occupational diseases, such as silicosis, lead poisoning, cadmium poisoning, and many others, but such relative problems as overcrowding, fatigue, and personal and mental hygiene; exposure to abnormal temperatures, pressures, and humidities; ventilation, heating, and lighting. It is a science which requires the combined activity of medical personnel (doctors and nurses), engineers, and chemists to evaluate the exposures and determine the means of eliminating the hazard. The engineer surveys the workplace, takes air samples at the breathing level of the workman, and analyzes the work exposure. The chemist determines in his laboratory the exact amount of toxic material collected in the sample, which represents the exposure of the workman. The doctor must diagnose the occupational disease, recognize its cause, and evaluate the disability. Together, all three must correlate the data obtained and devise efficient methods, medical or engineering or process changes, for controlling or minimizing the dangerous condition and for studying the effectiveness of these measures. The plant doctor, in addition, must aid in the readjustment of the incapacitated worker and provide facilities for prevention. Industrial hygiene, however, is of no avail without the understanding co-operation of management.

Jan 1, 1945

By J. E. Harris

By elimination of other possible nucleation processes, it has been demonstrated, for commercially pure magnesium and a Mg-Al alloy, that at stresses less than that necessary for triple-point cracking creep cavities are most probably nucleated heterogeneously at second-phase particles. Evidence for the existence of such particles is presented and the role of grain boundary sliding in the nucleation process is examined quantitatively. DURING creep deformation of polycrystalline magnesium and its dilute alloys in the temperature range 0.45 to 0.7 Tm (Tm = absolute melting temperature) cavities form mainly along grain boundaries oriented normal to the stress axis and failure eventually occurs by their growth and impingement.' The possibility of low-ductility creep failure of magnesium-alloy reactor cans during service has prompted a number of studies of cavity formation in these materials.2-5 In this paper divergent theories of cavity nucleation6-10 are examined critically and conclusions drawn regarding the most probable mechanism of formation of cavities in magnesium. The paper is divided into two parts. The first section consists of the review and quantitative assessment of the possible role of grain boundary sliding in the nucleation process. In the second part an experimental program is described where an electron-microscope technique has been used to determine if second-phase particles exist in as-received commercially pure magnesium and in a magnesium alloy 1) THEORETICAL REVIEW Possible nucleation sites for creep cavities are: a) high-angle grain boundary triple points,11-14 b) subboundary/grain boundary intersections,15-18 c) ledges in the grain boundary, 19-25 d) second-phase particles. 9,26-30 Each of these possibilities is now considered with special reference to deformation of magnesium. 1.1) Triple-Point Cracking. The stroh31 condition to nucleate fracture is: " > vr [1] where ss = applied shear stress, ? = surface energy, C = shear modulus, L = length of sliding interface. This relationship is independent of the nature of the interface and it is possible to calculate the stress concentration at the end of a sliding high-angle grain boundary and thus deduce, approximately,* the minimum applied stress necessary to nucleate triple-point cracking. Such theoretical predictions for Nimonic alloys have been made by McLean13 and found to agree quite closely with the minimum stress determined by experiment. Stresses capable of nucleating triple-point cracking should also be sufficient to nucleate fracture at a grain boundary due to intragranular slip, for the lengths of sliding interface in the two cases are approximately equal. Thus the minimum stress for triple-point cracking should represent a demarcation between failure due to general "cracking" and that due to cavitation. Hauser, Landon, and Dorn32 have demonstrated that for polycrystalline magnesium in the temperature range 78° to 298°K the fracture stress is inversely proportional to the square root of the mean grain diameter. As pointed out by stroh31 this result indicates that Eq. [I] describes the fracture characteristics of magnesium at low temperatures. Heal3 has reported that for rapid deformation (112 pct hr-1) of polycrystalline magnesium the transition from cracking to cavitation occurs in the temperature range 175" to 275°C. He also presented the fracture-stress values for the same material tested under similar conditions. From Eq. [I] taking G = 1.3 x 10" dynes , ? = 600 ergs . cm-2,33 and L = 0.017 cm, a Stroh-McLean13,31 tensile stress of -266 kg. cm-2 is calculated, corresponding to a transition temperature of -190°C; this is in

Jan 1, 1965

By Robert Glass Cleland

DURING the closing month of 1929, Walter Douglas found his health impaired by the strain of many difficult years of alternating prosperity and depression, and in April 1930 resigned the presidency of Phelps Dodge. Douglas was succeeded by Louis S. Cates. The choice broke a tradition that had been held inviolate for almost a hundred years. For the first time in its long history, the direction of the company's policies and operations was entrusted to a stranger without previous Phelps Dodge background, training, experience, or tradition. But the choice was wisely made. For a time at least, the path of Phelps Dodge was to run through rough and dubious ground, and no man in the United States was better qualified to blaze that trail than Louis Cates. After graduating from the Massachusetts Institute of Technology, Cates had served a rough and financially un- profitable apprenticeship at one of the century-old mining camps of Chihuahua, Mexico. Following his return to the United States and a brief interlude as assistant to the president of the National Steel and Wire Company, he had resumed his mining career, first as timekeeper, then as

Jan 1, 1952

"The Garfield plant of the American Smelting & Refining Company is situated about seventeen miles west of Salt Lake City, on the Los Angeles & Salt Lake Railroad, and has freight service by the Denver & Rio Grande Western, Western Pacific and Bingham & Garfield Railways.The site lies between the picturesque Great Salt Lake, with its mountain islands, and the northern point of the Oquirrh Range, which forms the western boundary of the Salt Lake Valley.The location includes several hundred acres of land rising from the southern shore of the lake, selected on account of its adaptability to the economical handling of materials by gravity methods.The smelter is a custom smelter, treating copper ores and concentrates produced in Utah and adjoining states.The ores treated consist mainly of oxides from the Tintic and Park City Districts, sulphides from Bingham District, and concentrates from the mills of the Utah Copper Company, from mills in California, and copper precipitates from the Ohio Copper Company. The last product comes from low grade ores of Bingham Canyon.The following figures represent approximately the daily consumption of materials:Ores and Concentrates…2,700 tonsLime sand…100 ""Coal…350 ""Oil for Roasters…240 Bbls."

Jan 1, 1925

By Chikao Nishiwaki

INTRODUCTION The Japanese dependency for mineral raw materials from foreign sources increased rapidly within the 20 years since the Korean war. During this 20 year period Japan has attempted to industrialize and develop her economy while depending mostly on heavy import of nearly all kinds of mineral raw materials. She has fabricated them using energy generated mostly by mineral fuel that are also imported. Fabricated goods are either used domestically to accelerate more fabrication industry or exported after adding more refinement or fabrication. In this paper iron ore as a major raw material for the Iron and Steel industry, three major base metals, copper, zinc and lead, and petroleum as a major energy source have been selected as examples to represent the general features of various kinds of mineral raw materials that are imported. Among other important mineral commodities for which Japan dependa upon foreign sources are: Aluminium, nickel and cobalt, potash and phosphorous 100 percent dependent and tin, tungusten, chromium and molybdenum over 95 percent dependent. IRON ORE Statistics for the important iron and steel raw materials, namely iron ore, coal and scrap iron are shown in Tables 1, 2 and Fig. 1. Iron ore is by far the most important and basic among these three commodities. There has been practically no steel or iron imported as a metal into Japan during this period. Iron ore, including aggregate such as pellets, and metallurgical coal are mostly transported in large ore cargo boats to the port where very efficient port facilities unload them directly at the steel mill site. As a result

Jan 1, 1976

Jan 1, 1966

Jan 1, 1903

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Jan 1, 1907

By L. F. Stutzman, George Thodos

A new graphical method, which is a modification of that proposed by Buckley and Leverett', is presented for the determination of the displacing fluid saturation at breakthrough for frontal drive mechanisms. This method is applicable to all types of fluids, which may be either soluble or insoluble in the oil at reservoir and injection conditions. This adaptation has unique advantages in handling problems in which either liquids or gases are the displacing fluids. INTRODUCTION In the displacement of oil from a reservoir with water or gas injected into the formation or by the expansion of a gas cap, the determination of breakthrough or flood advance is important to define the initial and subordinate phases of the operation. Thus, the determination of the displacing fluid saturation at breakthrough is fundamental to the establishment of over-all reservoir production. Methods for analyzing this saturation and for calculating production rates have been previously reported1,'*".". All of these methods utilize the rate equation for linear flow developed by Buckley and Leverett1. xs = QT - Qn/A? (?fu/?Su) .....(1) Sp where f, represents the volumetric fraction of displacing fluid in the total flowing fluid within the reservoir as is defined by: fo = 1/1+ ku/kd µn/µn .......(2) Since the time, ?, necessary for the flood front to travel distance ?X is unknown, Eq. 1 cannot be solved directly for the determination of the breakthrough point. Therefore, it becomes necessary to solve Eq. 1 simultaneously with an equation representing a fluid bal-ance on the reservoir behind the flood front. To develop such a fluid balance equation, it has been assumed that the fluid composition is uniform in the reservoir behind the flood front. Based upon this assumption, the follow-ing equation can be derived from a material balance on the displacing fluid: x = (?X) s Dx ? x=0 [ Snx - Sn1 ] dx = QT - Qn/A? It is readily observed that the displacing fluid satura-tion behind the flood front, Snx, may be determined through the simultaneous application of Eqs. 1 and 3. Although the approach may vary, this objective re-mains the same for all of the previously mentioned graphical or analytical methods. After Sox is determined, it is then possible to calculate the gas-oil and/or water-oil ratios and the rates during the initial and subordinate phases of production, and thereby define the production history of the reservoir. In this presentation only the de-termination of Snx is considered, and the reader is re-ferred to the several texts in reservoir engineering2,4,5 for a complete discussion on the methods for establish-ing the production history of a reservoir. PROPOSED METHOD FOR DETERMINING Snx Since at any time the quantity, QT - Qn/A? is a constant, Eq. 1 may be expressed in differential form as follows: dxsn = QT - Qn/A? d (? fn/? Sn) sn .....(4) Eq. 4 may be substituted directly into Eq. 3 to obtain: ? fn/? Sn ? [ Snz - Sn] QT - Qn/A? d ( ? fn/? Sn) = QT - Qn/A? ...............(5) Eq. 5 simplifies to the expression: ? fn/? Sn ? [ Snz - Sn] QT - Qn/A? d ( ? fn/? Sn) = 1 ....(6)

Jan 1, 1958

By Roger M. Zimmerman

The G-Tunnel heated block experiment is being conducted on the Nevada Test Site (NTS) as part of the Nevada Nuclear Waste Storage Investigations project (NNWSI). The purpose of the ambient temperature testing ph se is to evaluate rock-mass mechanical properties of a block (- 8 m3) under biaxial stress changes up to 7.5 MPa above an initialization in situ value of 3.1 MPa. Results indicate that the modulus of deformation ranges from 9.7 to 17.0 GPa and Poisson's ratio ranges from 0.21 to 0.33. In general, the higher values of the modulus and Poisson' s ratio were influenced by fracture propagations parallel to the compressive stress field. Other measurements indicated that cross-hole compression (p) wave velocities and single fracture permeability values were relatively insensitive to stress changes above the in situ value.

Jan 1, 1984

By John D. Welsh

Jan 1, 1985

By R. J. Reynik, F. R. Meeks

IN the classical paper1 of Mehl and Rhines entitled "The Rates of Diffusion in the Alpha Solid Solutions of Copper", the authors state: "It has been mathematically demonstrated that the treatment of the data as though the diffusion were taking place between two flat plates instead of radially in a cylinder has no appreciable effect upon the results. Were the bars of a much smaller diameter, a modification of the analytical treatment would have been required." Unfortunately, the errors in the reported concentrations are much too large to neglect, as shown in the results below. A planar treatment of diffusion data assumes that the reference planes separated by a nominal distance (AX) have identical areas. An adjustment must be made on the concentration data should the successive diffusion planes differ in area. The Mehl-Rhines' diffusion samples were cylindrical with copper electroplated onto copper-based alloys. Successive surface areas through which diffusion occurs are in the ratio ri/r1, where ri is the radial distance between the center of the sample and the center of the i th shell to which the host (alloy) atoms diffuse, and r1 is the radial distance between the center of the sample and the center of the innermost (i = 1) experimentally reported shell from which the alloy atoms diffuse. Hence, ri/r1 (i = 1, ..., n layers) is a dimensionless correction factor to be multiplied by the reported concentration data before planar-data analysis is attempted. In the forty-seven samples reported, the original interface between the copper alloys and the electroplated copper was located at a mean distance of 8.255 mm from the center of the samples. The successive layers, machined off the samples, were approximately 0.0762 mm thick. The distance (xi) at which concentration (ci) was reported was always a distance measured with respect to the original interface, that is, with respect to the fixed distance of 8.255 mm. Hence, the as yet undiscovered Kirkendall Effect was precompensated. The values of ri and r1 are therefore given by ri = 8.255 + xi and Y, = 8.255 + x,. The illustrative table below lists the position xi (mm), ri (mm), the value of ri/r1, the reported concentration (ci) in weight percent (only valid for radial analysis of data), and the corrected concentration [c'i = (ri/r1)ci] in weight percent (only valid for planar analysis of data). Similar tables can be constructed for the remaining forty-six samples. The corrected data can be used to re-evaluate the diffusion coefficients for the reported systems.

Jan 1, 1965

By AIME AIME

OVER-ALL operations of the oil industry, as measured by production of crude oil and consumption of products, are almost exactly of the same magnitude as a year ago. Does this mean that the great oil industry has been undisturbed by the war? Has this industry, so vital to the prosecution of the war and to the maintenance of our way of life, been unaffected in its operations? No indeed - changes within the industry are great. It has been called upon to revamp its trans¬portation methods so as to move about one fourth of the total amount of crude and refined products by railroad tank car instead of by ocean-going tankers. Its fundamental internal economy, based on maximum gasoline yield from a barrel of crude, has been relegated to memories of the past. Rationing of oil products, which has been forced upon us in face of an abundant supply, is not only disagreeable medicine but is in itself completely disruptive to the marketing end of the-business.-

Jan 1, 1942

By Truman H. Aldrich

The red, or fossiliferous, ore is found in the Clinton group of the Silurian formation. This group is from 100 to 500 ft. thick in Alabama, and its outcrops have been mapped by the State or the U. S. Geological Survey. In some places, it is entirely missing (doubtless islands in the Silurian Sea). In Etowah County, in part of Greasy Cove and vicinity, the upper seam is a coral reef impregnated with the red ore; in this same county, step faults bring up the ore in three or four practically parallel ridges. In Blount County and on Raccoon Mountain, the ore runs under the carboniferous rocks and outcrops in the valleys. When examining the logs of holes drilled for oil, wherever the drill has gone deep enough, the writer has found the Clinton group underlying the Warrior coal field. The following records of holes drilled primarily for oil, given in Bull. No. 22, Geological Survey of Alabama, show the presence of either ore or red rock, and suggest vast resources yet to be outlined and developed for ore in the future. The locations are given by number on the map. Hole No. 1 was drilled 6 miles southeast of Russellville, Franklin County, by the Woodward Oil & Gas Co. It passed through 160 ft. of the Clinton, but only a small show of red ore was found at 1280-1400 ft. A test well, No. 2, drilled near Atwood, Franklin County, in sectioil 26, township 8, range 14, penetrated the Clinton at 1608 ft. and found 38 ft. of limy red rock, also 8 ft. of some blood red ending at 1820 ft., making 46 ft. of red rock in all. It is reported that some good ore was cut through but this work was done by a churn drill. At least 400 ft. of the formation was classified as Clinton. Well NO. 3, called Frankford Well, was bored by S. A. Hobson and associates in the northwest quarter of section 7, township 6, range 12, Franklin County. At 927 ft., it is supposed to have entered the Clinton; the log is as follows: Ft. Sandy limestone with reddish, high ferruginous argillaceous inclusions 10 Same growing more ferruginous................................ 18 Hematitic limestone......................................... 30 Same with slightly less iron.................................... 23 81

Jan 1, 1925

By A. A. Bauer

The ?-to-? transformation has been studied in zirconium alloys containing 22 to 70 wt pct U. In this range of compositions the ? phase can be retained by quenching. Transformation to ? occurs by a nucleation-and-growth process. The diffusion of atoms to preferred lattice sites to yield a partially ordered structure apparently controls the rate of reaction. Alpha uranium and a zirconium precipitate from the supersaturated E phase initially formed in alloys outside the equilibrium E phase composition limits. ZIRCONIUM-Uranium alloys have long been of interest for reactor-fuel applications because of the low thermal-neutron cross section of zirconium. Considerable information is available on the various properties and behavior of these alloys1 although there had been a number of areas where information was incomplete. As part of a program to provide more detailed knowledge in these areas, the presently reported investigation was undertaken. The constitutional diagram of the zirconium-uranium system is shown in Fig. 1.' The system is distinguished by a region of complete solid solubility between the body-centered cubic ß-zirconium and ? uranium phases and the existence of an intermediate phase in the vicinity of 50 wt pct U. This intermediate phase, designated as E, is reported3 to have a primitive hexagonal structure with a = 5.03 and c = 3.08A. The structure is partially ordered with zirconium atoms at the 0, 0, 0 position and zirconium and uranium atoms located randomly at the 1/3, 2/3, 1/2, and 2/3, 1/3, 1/2 positions. While the E phase may be nominally designated as of UZr2 stoichio-metry, the random distribution of uranium and zirconium atoms permit a considerable range in composition. Of interest in the research performed were alloys in the range from 20 wt pct (10 at. pct) to 70 wt pct (47 at. pct) U. In this range of compositions the body-centered-cubic ? phase can be retained either completely or partially on quenching. The nature and kinetics of transformation of the ? phase were the subject of study. Proceeding concurrently with the presently reported work was an investigation by Kearns4 which has since been reported. Kearns studied alloys containing 50 to 60 wt pct U prepared from sponge zirconium. While the work reported here is for alloys prepared from crystal-bar zirconium and the techniques of study are to some extent dissimilar to those employed by Kearns, general agreement so far as results and interpretation can be reported. Experimental Techniques—Alloys were prepared and the transformation of the ? phase studied during interrupted-quench and quench-and-temper isothermal heat treatments by means of hardness measurements and X-ray diffraction and metallographic techniques. The isothermal transformation of the ? phase on quenching and tempering was investigated further employing dynamic-modulus measurements. Electrical resistivity and limited Hall coefficient measurements were also obtained as part of the study. Alloy Preparation and Heat Treatment— Alloys containing 15, 20, 22, 30, 40, 45, 50, 55, 60, and 70 wt pct U were prepared from as-reduced uranium and crystal-bar zirconium. The alloys were double arc melted by consumable-electrode are-melting techniques. The final ingots were forged and rolled at temperatures between 790" and 840oC to 1/4-in. rod and 1/8-in. sheet. Chemical analyses of the fabricated alloys were

Jan 1, 1961

Jan 1, 1967

By J. C. Trantham, J. W. Marx

From 1955 to 1958 the Phillips Petroleum Co. conducted a series of small scale counterflow combustion field tests in a tar sand about 60-ft deep and 6 to 12-ft thick near Bellamy, Mo. A total of seven different well patterns, including conventional five-spots and seven-spots plus a 15-well line drive pattern and a 10-well radial pattern, were employed. Electric heaters, gas burners and wellbore fuel packs were tested as counterflow ignition devices. Direct drive ignition followed by reversal to counterflow operation was not possible in this case because of formation plugging by the semi-solid tar during the direct drive phase. Sustained counterflow burning was achieved with wellbore fuel packs under conirolled conditions which permitted close correlation of fire front velocity, air velocity, air-oil ratios and yields for a wide variation in process parameters. The tar in place was about 10' APl with a reservoir viscosity greater than 500,000 cp. The composite oil prodlcct was 26' API with a viscosity in the range of 5 to 15 cp. Vertical sweep efficiency in the line drive pattern was essentially 100 per cent, with no evidence of gravity segregation. Original tar in place ranged between 800 and 1,000 bbllacre-ft, specific rock permeability averaged about 800 md before burning and effective air pemeability with residual oil and water in place (at the time of ignition) averaged 250 md. The volume of oil recovered during stabilized line drive counterflow burning represented about 67 per cent of the volume of tar originally in place in the burned out zones. A minimum was found when air-oil ratios were plotted against formation air velocities, and a limiting air velocity existed below which the counterflow fire front reversed and burned back over its own trajectory, using the residual coke left behind. INTRODUCTION Early in 1955 the Phillips Petroleum Co. began preparations to field test counterflow underground combustion as a method for producing oil from high viscosity hydrocarbon deposits, such as bituminous (tar) sands. At that time all published information on the use of underground burning io increase oil recovery was based on the direct drive process, in which the fire front moved through the formatim in the same direction as the injected air stream. Such direct burning is not applicable to many heavy oil sands or to most tar sands because the heat-thinned native hydrocarbon congeals in the cold rock ahead of the fire front forming a gas permeability block which smothers the combustion. Laboratory experiments first demonstrated that this permeability blocking would not occur if the fire front and the air stream moved in opposite directions. In this counterflow (reverse) burning process the heated heavy oil or tar is driven back through the combustion zone. Here thermal cracking produces relatively light hydrocarbon products which pass through the heated rock behind the fire front (largely in the vapor phase) and are incapable of causing a gas permeability block.' Exploratory wring revealed that consolidated bituminous sandstones with a combination of tar saturation, permeability, thickness and depth favorable for experimental field testing existed at several points in western Missouri. By the fall of 1955, a test site for determining technical feasibility of the counterflow process under field conditions had been selected near Bellamy, Vernon County, Mo. — about fifty miles north of Joplin. The pay zone was too thin and too shallow to constitute a commercial prospect, but these same factors permitted controlled experimental operation with a small compressor installation and with a large number of monitor wells. These were needed for adequate observation of the underground phenomena at reasonable cost. RESERVOIR CHARACTERISTICS The reservoir chosen for the experimental field tests was a 124 thick section of tar sand extending from 49 to 61 ft subsurface, with shale and siltstone laminations sealing the top and bottom. This section was part of a larger 30-ft thick tar sand deposit which extended both above and below the test zone. Core analyses showed that the 12-ft sand was effectively subdivided into two approximately equal sections, with the lower zone being consistently more permeable than the upper zone. The most significant laboratory core data are summarized in Table 1. The line drive test which is the principal subject of this report utilized only the lower 6-ft thick zone, with the upper zone regarded as part of the 55-ft overburden. WELL PATTERNS The over-all field test program involved a total of seven different well patterns, including conventional five-spots and seven-spots plus a 15-well line drive pattern and a 10-well radial pattern. In some of the tests the full 12-ft zone was employed; in other cases only the more perme-

Jan 1, 1967

By George Holderer

THE Enos Coal Mining Co. owns an area underlaid by coal, of approximately 5000 acres. This property is situated 9 miles from Oakland City, in the southern part of Indiana. The mine has been in operation 5 years, during which time some 350 acres have been stripped, and stripping is now proceeding at the rate of about 100 acres per year. TOPOGRAPHY These coal lands consist of gently-rolling agricultural fields which in times past were farmed for wheat. There is no timber and but very little brush to contend with. The overburden varies from 10 to 60 ft. in depth. A thin bed of slate overlies the coal, followed by limestone, which varies from 3 to 15 ft.; this, in turn, is followed by sandstone, slate, shale and clay. There is a very wide variation in the thickness of all of these beds. The coal has an average thickness of 5 ft., and is a good grade of high-volatile bituminous. MINING OPERATIONS Briefly, the sequence of operations is: drilling holes with churn drills; blasting with L. 0. X.; stripping overburden to uncover coal and, finally taking up the coal, which is sent to a tipple for cleaning and sizing. In order to show what is being accomplished by the use of L. 0. X., results will be shown from May to November, 1926, inclusive, and compared to the same period in 1925. No work was done in No. 1 pit during May, 1925, hence all figures are unduly low for this month. Drilling There are in use 8 No. 44 Loomis clipper drills, caterpillar traction with gasoline engines; recently these were equipped with extra heavy stems, measuring 26 ft. overall and 4 ½ in. dia., to increase the speed of drilling. In addition, 4 No. 1 ½ G non-traction drills have been acquired, and are used to save the time of the larger drills when recleaning is necessary.

Jan 1, 1927