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By J. C. Bayles

It is seldom the privilege of one who contributes to the Transactions of a technical society, to describe a new industry in which, by processes employed for the first time, are attained results of conspicuous value. There are but few such patches of virgin soil worth the tilling, within the area circumscribed by the industries which have experienced a regular and uniform development. New and startling methods in production are often announced as about to be introduced; but, as a rule, they take their place among the " large desires with most uncertain issues," or give new significance to the historic words of an eminent statesman concerning " the bright beginnings and the bitter end of a halcyon and vociferous proceeding." In this paper I shall have the pleasure of briefly describing a new industry which has been established without announcement or proclamation — the manufacture of serviceable pressure pipes of great strength, from strips of steel or iron wound spirally, heated only along the overlapping edges, welded by hammering and finished into tubes of uniform diameter, and of such length as mag be found convenient in handling and transportation. As such tubes are now manufactured on a considerable scale, in a range of sizes which will soon include everything between 4 inches and 30 inches, and as much larger as may be needed, both process and product are likely to be of interest to engineers in all departments of professional work. The raw material of the industry is the ordinary sheet-iron or steel of commerce, of such lengths and widths as it is convenient to roll. The range of the ganges of the metal which can be employed has riot yet been determined. The lightest metal thus far successfully made into pipe is No. 29 iron, and the heaviest a steel gauging somewhere between 12 and 14. Heavier machines are now building which will bend steel .165 of an inch in thickness, or No. 8 of' the Birmingham gauge. Probably No. 20 or No. 22 will be the lightest used in making commercial pipes; hut the experiment with No. 29 was interesting as showing the readiness with which the flame can be controlled. To get a welding heat with such thin

Jan 1, 1888

By M. L. Requa

This paper is abstracted from the report of the Appraisement Committee of the Independent Oil Producers' Agency, of which the writer was Chairman. The other members of the committee were M. V. McQuigg and R. S. Haseltine. To Thomas Cox, engineer in charge of the investigation, and to his efficient staff of assistants, is due the credit for the detail work necessary in carrying out the plan of the Committee. It treats only of the valuation of the lands, wells, and piping, without going into details of equipment and other features. It was recognized, early in the operation, that the value of oil lands was the value of oil ,to be extracted and marketed, less the costs attendant thereon. Referring this back to the costs in cents per barrel, it became obvious that surface improvements, absolutely necessary in the production of oil, from wells then drilled, had no separate and independent value aside from the value of the land, but that any excess equipment, not necessary for the production of oil from present wells, such as drilling tools, well casing, etc., should be given a present condition value. In valuing the properties of the Independent Oil Producers' Agency, the Committee has considered the following facts: 1. That from each property there will ultimately be produced a certain total quantity of oil. 2. That in the production of that oil a certain total quantity of money will be expended. 3. That a certain total amount of money will be received from the oil. 4. That the total net receipts will be the total gross receipts less the cost of development and production. 5. That the present value of the net receipts must be such an amount that when invested by a purchaser it will be returned with 8 per cent, interest additional during the life of the property. The initial procedure consisted in making a general reconnaissance of the entire district in which the property was located and determining the lithological and structural conditions underlying the area. The data obtained from each individual tract comprised the logs of all the wells

Jan 1, 1918

By J. A. Goebel, S. Rosen

IN the NiAl phase diagram the NiAl (CsC1-type) phase field extends over a large composition range. At elevated temperatures the nickel-rich phase boundary extends to a composition of about 70 at. pct Ni, a value which is within 5 at. pct of the Ni3A1 (Cu 3 Au-type) phase boundary.' At room temperature, however, the maximum nickel content is only about 60 at. pct. Experiments have shown that alloys containing greater than 63 at. pct Ni when quenched from temperatures below 1000°C contain the equilibrium phases NiAl and Ni3A1. On the other hand, when these same alloys are quenched from temperatures above 1000°C and examined microscopically, a typically martensitic decomposition product appears in the microstructure as shown in the micrograph of Fig. 1. The structure of the martensitic phase has been determined by employing powder X-ray diffraction techniques to be an "ordered" AuCu type (Strukturbericht Llo, space group P/4 mmm - DL). The diffraction pattern of this phase differs from that of AuCu in the appearance of superlattice lines. The structure is shown in Fig. 2. The open circles represent nickel atoms and the half-shaded circles represent nickel and aluminum atoms which are randomly distributed. The sites represented by half-shaded circles would be occupied solely by nickel atoms at a stoichiometry of Ni3A1. The alloys used in this investigation were prepared from 99.99 wt pct Al and 99.99 wt pct Ni by arc melting charges of varying compositions in a water-cooled copper hearth using a tungsten electrode in a gettered argon atmosphere. In all cases chemical analysis agreed within $ at. pct with the nominal compositions of the alloys. Annealing treatments were carried out in a vertical resistance furnace through which a stream of argon gas was flowing. Specimens, which were wrapped in tantalum foil, were quenched by allowing the specimens to drop into a bucket containing iced brine. X-ray diffraction patterns were obtained from -325 mesh powder specimens by using a 114.8-mm

Jan 1, 1969

By Robert L. Wilson

Computation of reserve tonnages, stripping ratios, and grade of ore has long been a revolting aspect of the young mining engineer's job. Weeks at the desk calculator may turn into months before a single job is completed. Then many additional hours are necessary to check the calculations. During the last decade, computing machines have been widely publicized as instruments which will accomplish fantastic feats. Tales of their magical qualities have overshadowed their most basic characteristics-that of being a labor-saving device. Prior to a discussion of the electronic calculator's use on a mining problem, it may be well to point out that these machines are neither magic nor will they replace the judgment of an experienced engineer. In short, the "mighty morons," as the computors are sometimes called, are excellent labor savers but must be used correctly. They are not a substitute for thinking.

Jan 6, 1961

By John H. Ratcliffe, Hans T. Lundberg

In airborne gravity surveys effects of acceleration and irregular movements of the aircraft must be balanced out or overcome. The gradient of vertical gravity is recorded, therefore, by using two masses instead of one. As the amplitude variations are infinitesimal and difficult to measure accurately, at of gradient during flight is positive or negative. The positive portions of the pattern can then be indicated and contoured. Even with these simplifications, the source of energy must be exceptionally stable. General Principles: In the conventional gravimeter the weight of a standard mass is determined at a number of selected points within the survey area. In most systems weight is determined by comparing the gravity pull with extension or torque produced in a wire spring. The instruments employed are sensitive to the slightest movement; they cannot be used on a moving platform unless velocity is kept strictly uniform.

Jan 8, 1959

By J. R. Eckel

It has long been known that mud properties affect drilling rate and that drilling with water is as much as six to .seven times faster than with mud. However, it is not known why drilling rates with mud are lower. Recent studies show what fluid properties govern microbit drilling rate and also provide a quantitative correlation of these fluid properties and hydraulics with microbit drilling rate. All the microbit tests reported in this paper were made with a low permeability (about 10 md) limestone. They were conducted at constant bit weight and rotary speed with varying fluid properties, flow rate Q and nozzle dinnteter d. The tests showed that (1) drilling rate in a given system with constant circulating rate and nozzle velocity is a function of the kinematic viscosity [viscosity /density, (cp)/ p (density)] of the drilling fluid measured at near bit nozzle shear rates; (2) the combined effect of fluid properties and hydraulics on microbit drilling rate is defined by a Reynolds number function (kQp/dp); (3) for the same kinematic viscosity, drilling rate is independent of solids content; and (4) for the same kinematic viscosity, drilling rate is independent of fluid loss. INTRODUCTION The fact that mudding up reduces rate of penetration is well known, but the reduction varies from well to well. The rate with mud may be 80 percent of the water rate or it may be as low as 15 percent. Since this reduction of up to seven-fold takes place under conditions of constant bit weight, rotary speed and mud circulating rate in a uniform formation, it can only be a result of the change in fluid properties. Previous work1-" both in field tests and in laboratory microbit tests) showed that drilling rate with mud is lower than with water (Figs. 1 and 2). Microbit tests also confirm, at least qualitatively, the field observation that drilling rate slows with increased pressure differential from borehole to formation (Fig. 3). The qualitative effect of drilling rate of bit weight, rotary speed and rate of mud circulation are also the same for the field and microbit rig. For these reasons, the industry generally accepts microbit results as being qualitatively meaningful in terms of field application.

By C. O. Brawner

INTRODUCTION Tailings dams up to about 200 ft. high are proposed to store tailings for a major mining operation on Marinduque Island in the Philippines. The original design of the dam utilized a compacted laterite starter dam followed by hydraulic placement of cycloned sands to form slime retaining dykes along the outer face of the dam. The upstream method of construction was proposed. In view of the failure of numerous tailings dams in Chile during the EL Cobre earthquake (I), an investigation was performed to assess the earthquake stability of the proposed dam. This included a soil investigation on the first cycloned sand dyke, which had been built to a height of 45 ft. Results indicated that the density of the sand was much lower than existing empirical criteria consider to be necessary for resistance to liquefaction. As a result, the dam was redesigned. The downstream method of construction was selected and a yearly construction program was developed to make use of sand available by cycloning. To increase shear strength, improve resistance to liquefaction, and to utilize steeper slopes, compaction of all sand in the dam was specified. A special underdrainage layer and toe drains were incorporated in the design. Details of the decant system and surface erosion alternatives are described. SITE CONDITIONS The mining project is located in the Philippine Islands. At the present annual rate of production, about 4,230,000 cu.m. of tailings will be produced yearly. The volume requirements for tailings storage design for the first 10 years of operation are in the order of 45,000,000 cu.m. The topography near the mine is mountainous with many gullies and canyons carved out by high intensity rainfall and runoff. The bedrock, which is generally shallow and weathered for a considerable depth, is overlain by laterite soils. Vegetation is comprised largely of palms, banana trees, and tropical shrubs and grasses. Precipitation is heavy. The average yearly rainfall over 24 years is 65.2 in. and the maximum recorded 24 hour rainfall is 9.0 in. High intensity rainfall is associated with typhoon storms, which are a seasonal threat inthe Philippines. Fig. 1 shows a summary of monthly precipitation.

Jan 1, 1972

G. SHERBURNE ROGERS,* Washington, D. C. (written discussion ?).- Mr. Neal's paper on the petroleum hydrology of the Mid-Continent district is a welcome contribution on a subject concerning which none too much is known; it is, I think, the first published description of the chemical character of the oil-field waters of the great Mid-Continent area. When studying the oil-field waters of the California fields several years ago, the differences in chemical composition between waters occurring at various horizons seemed to be sufficient to enable the operators to use water analyses as a basis for determining the source of the water flooding a well; and it is gratifying to find that, Mr. Neal has arrived at a similar conclusion. As Mr. Neal points out, the Mid-Continent waters are very different in character from those of the California fields, and casual. inspection

Jan 3, 1919

By H. I. Young

Inasmuch as there has been a great deal of activity in this district recently, a paper of this kind should treat of all the various phases of mining, namely, prospecting, developing, and operating. Prospecting .. Where ore is found at a depth of 100 ft. (30 m.) or more, the prospect work is done by churn drilling. Several makes of churn drills are used in this work, both steam- and gasoline-driven machines being used. The drilling is usually started with a 6-in. bit, and the size of the bit is reduced, if necessary, as the hole is advanced. It is general practice to drill from 100- to 400-ft. holes, but this is governed entirely by the location and formation of the ground. In drilling sheet ground, close spacing of drill holes is unnecessary, but in narrow orebodies, the holes are spaced from 15 to 50 ft. (4.6 to 15 m.) apart. Ten years ago, very few assays were kept of the drilling, but during recent years records have been kept very accurately, showing the location, elevation, assays, and also the vertical section of the hole. After the orebody is reached, cuttings are taken every 2 or 3 ft. (0.6 to 0.9 m.) samples being sometimes taken by pouring the water off the cuttings and taking a portion of the coarse material for assay. It has been found, however, that very often the sludge material poured off with the water contains high mineral values. To overcome this, cuttings from each 2 or 3 ft. are put in a container, and, after the water is evaporated, sample for assay is taken by means of Jones samplers. Permanent records of cuttings showing various formations are kept in glass jars or glued on large cards. Drilling at present is costing from $1.25 to $1.50 per foot. In pre-war times, the drilling costs ran from 75c. to $1 per foot. Development After proving property by drilling, shafts are put down to the ore-body. These are usually vertical shafts, either single or double compart-

Jan 1, 1918

By W. D. Robertson, H. H. Uhlig

The intermetallic compounds MgzSn and Mg2Pb are two of the important series of stoichiometric compounds which magnesium forms with elements of the fourth group of the periodic system. Since there is a complete series of compounds, all possessing the same comparatively simple structure, a unique opportunity is presented to study their properties with respect to increasing atomic number of the anion as it varies from silicon and germanium, through tin and lead. The present work deals with the two lower members of this group, and it is hoped eventually that additional data regarding the silicide and germanide will be obtained. The results of such a complete study provide part of the essential basis for the empirical correlation and theoretical treatment which, in other systems, has contributed to an understanding of inter-metallic compounds and the metallic'state in general. Some experimental data are already available in the literature. However, they are fragmentary and limited in significance owing to the methods of preparation employed and the impure materials available at the time. It was our objective, therefore, using pure metals and improved metallurgical methods of preparation, to produce stoichiometric compounds of high purity for the study of their electrical and chemical properties. We felt that a detailed investigation of chemical properties, about which relatively little is known, combined with electrical properties, would be a significant contribution to the understanding of these compounds and in particular to the mechanism of corrosion associated with types of bonding in alloy systems. The chemical studies are reported elsewhere. Previous Investigations Previous work concerning the electrical properties of these compounds was undertaken in connection with the establishment of the two phase diagrams which are available in Hansenl and Beck. The first comprehensive investigation of the electrical conductivity of magnesium-tin and magnesium-lead alloys was made by Kurnakov and Stepanov.3 This was followed by Grube and Voss-kiihler4 who studied electrical conductivity and thermal expansion over a wide range of temperature and who, unlike Stepanov, appreciated the significance of the large solid solubility of tin in magnesium and took some precautions to obtain an equilibrium state. However, at the time these investigations were made, neither pure magnesium nor

Jan 1, 1949

By Carl Beal

THE most important factors that should be given consideration in valuation of oil land are: (1) the amount of oil the property will produce; (2) the amount of money this oil will bring (based upon the future prices of oil) ; (3) development and production costs; (4) the rate of interest on the investment; (5) the retirement or amortization of invested capital; and (6) the salvage or "scrap" value of the equipment when the property is exhausted. These factors are of varying importance, and some of them may not enter all valuation problems, but most of them should be given consideration in any valuation even though only a rough estimate of the value of the property is desired. The value of a property may be changed over-night by the completion of important test wells, by the sudden water flooding, or by a change in the price of oil. The best a petroleum engineer can give is the value of the property under the conditions existing at the time the appraisal is made with a fair forecast of future action of the wells and of the price of oil. Our experience in the scientific valuation of oil lands is not broad and there is very little published information on the subject; it, therefore, becomes necessary in studying such problems to form comparisons with the factors involved in the valuation of mines-the closest parallel. One of the reasons for the lack of substantial progress in oil-land valuation methods has been the necessity of making an estimate of the future production of the oil property to be valued. Oil men and accountants have not generally conceded that such estimates could be made with any degree of accuracy. It has been shown, however, in several recent publications that with certain data available reasonably close estimates can be made. The accuracy of an appraisal depends chiefly on the accuracy of the estimates of future production and of the future price of oil. The accuracy of the former is sometimes necessarily based on geological inferences. Geology is not an exact science and geological data in connection with oil production cannot always be mathematically evaluated.

Jan 9, 1919

By Robert S. Lewis

Park City, Utah, elevation 7200 ft., is on the eastern slope of the Wasatch Mountains about 25 miles southeast of Salt Lake City, elevation 4200 ft. The town and surrounding mining district are served by two railroads: one, 28 miles long, is a branch of the Union Pacific R. R. and joins the main line at Echo; the other, 35 miles long, connects with the main line of the Denver & Rio Grande R. R. at Salt Lake City. The main shaft and important mine buildings, elevation about 8200 ft., of the Silver King Coalition Mines Co. are 11/2 miles by road to the southwest of Park City, and are near the head of Woodside Gulch. The property of this company is a consolidation of several groups of mining claims, and comprises an area that is roughly 4 miles long by 1 mile wide, the long axis of which has a N. 55" E. bearing. Geology A general geologic section through the property shows a basal formation of gray quartzite, called the Weber quartzite, above which seems to lie conformably the Park City formation. Both beds are of Carboniferous age. The Park City strata consist of a number of beds of limestone, with intercalated beds of quartzite, sandstone, and shale. The exact thickness is difficult to determine, but is apparently between 650 and 850 ft. Above the Park City beds and conformable with them lie the Woodside Shales. These thinly bedded fine-grained shales, about 1000 ft. in the thickness, are of no economic importance. They are overlain conformably by the Thaynes formation, which has about the same thickness and is composed of beds of limestone, sandstone, and shale. A thin bed of shale divides the formation into an upper and a lower part; the upper part contains more lime than the lower part. The Woodside shales and the Thaynes formation are of Triassic age. All the beds dip northwest, the dip is usually from 20" to 30°, but may be as great as 40°. In places, intrusions of diorite porphyry have deformed the beds. Marked faulting in zones of a northeast-southwest trend occurred after the intrusion of the porphyry. Later faulting in a

Jan 1, 1925

By G. H. Clevenger

The reagents now used in flotation consist of various acids or salts, which may be either electrolytes or non-electrolytes, dissolved in water and some substance or combination of substances which function as collecting or frothing agents. At times the only dissolved salts present are those naturally occurring in the water used. The general effect of the electrolyte is to greatly sharpen the separation between the gangue and the concentrate. Examples of this are: The use of sulphuric acid with zinc ores; and of sodium carbonate or calcium oxide (lime) with silver-gold ores. Crude pyroligneous acid is also sometimes used when avail able. Various oxidizing agents, such as permanganates, bichromates, etc., are added in the selective flotation of lead-zinc ores. Many other reagents for performing certain specific functions, either real or imaginary, have been proposed, and a number of them have been tried upon a working scale. The wild orgy of experimentation which is now going on in flotation exceeds even that which followed the introduction of the Washoe process for the treatment of Comstock ores, when, among other things, sage-brush tea and tobacco juice were reagents added to the pans. Out of all this will, of course, eventually come a more or less standard practice for the treatment of each class of ore. Omitting a discussion of the functions of frothing and collecting agents, the reagents used in flotation for this purpose may be classified under five general heads: (1) Essential oils; (2) fixed or fatty oils; (3) alcohols and their combinations with organic acids; (4) coal tar and its refined products; (5) petroleum and its refined products. A flotative agent of some kind is required in flotation as now practiced. A single reagent, as, for example, certain of the essential oils, may perform the dual function of frothing and collecting agent, or a mixture of substances may be required. In this country, the essential oils used have been wood products, and have been almost exclusively confined to the steam-distilled pine oils. At the present time, the supply of these is limited, and the cost almost prohibitive, so that their use has been dispensed with as far as possible. The oils and tars resulting from the destructive distillation of

Jan 1, 1917

By Julian Glasser, Arthur Fleischer

THIS country was faced with the possible necessity of utilizing nonbauxitic ores for producing aluminum during World War 11. Construction of four experimental plants to treat such ores by four different processes was authorized1-4 including one at Salt Lake City, for the conversion of Marysvale alunite to metal-grade alumina and potassium sulphate by the Kalunite process.' An aluminum reduction plant in Tacoma, Wash., with a capacity of 50 tons of aluminum per day, was constructed to handle the Kalunite alumina produced at the Salt Lake City plant. The alumina and aluminum plants were Defense Plant Corp. projects operated by Kalunite, Inc. and Olin Industries, Inc., respectively. Kalunite alumina differs from Bayer alumina in several respects, particularly in that the former contains potash instead of soda. The presence of potassium in the alumina feed to the cryolite bath was stated by aluminum technologists to be undesirable under the usual operating conditions of aluminum furnaces. In 1940, about 20 tons of Kalunite alumina produced in the Kalunite pilot plant, were reduced electrolytically in a 10,000 amp furnace at Battelle Memorial Institute and at the aluminum reduction plant at Neuhausen, Switzerland. These relatively small scale tests indicated that satisfactory commercial aluminum could be produced in a practical manner. The Tacoma plant reduced about 2,500,000 lb of Kalunite alumina to produce more than 1,200,000 lb of aluminum, in accordance with the accepted gractice for reducing Bayer alumina. It was desired to determine whether commercial aluminum could be produced on a large scale and to establish the technological differences in commercial reduction practice between Kalunite and Bayer alumina. In the course of collecting data, the effects of the abnormal chemical composition and physical properties of Kalunite alumina were observed wherever possible. Tacoma Reduction Plant The reduction plant had two pot lines, each with 120 cells in series, operated at approximately 32,000 amp. Each cell was provided with a single rectangular Soederberg continuous anode, with side-pin electrical contacts. Each cell was hooded and ventilated through a stack connected to 14 other cells, with 25,000 cfm blower. When the plant started operation in 1942, all of the cathode linings were of block construction. Rebuilt cells were of rammed paste construction.

Jan 1, 1952

By L. E. Young

THE purpose of this paper is to start a discussion on: (1) methods of supporting the immediate roof, particularly of local areas of poor roof, during the mechanical loading of coal; (2) methods of increasing the rapidity of the movement of the mining faces so that, without the use of cribs, jacks, pack walls, and filling, there will be no danger to men, equipment,, and working places from the subsidence of the overlying strata. In the Pittsburgh district the application of mechanical loading devices in mines working in the Pittsburgh seam, has been retarded by the difficulties of holding and handling the draw slate. Normally the thickness of this slate averages about 8 in. but the hardness varies, and a cut of coal cannot always be loaded without placing posts or crossbars to support the slate. Locally, the slate may be thicker and special methods of support may be required. If crossbars are placed to hold the slate when the coal averages 5 ft. in thickness, the standard methods of transporting the coal cannot be followed, and the use of conveyors may be desirable. Very little information is available on the effect of increasing the rate of movement of advancing or retreating break lines or longwall faces. A few British publications have presented some data but all such data relate to longwall faces that have moved not more than 6 ft. a day. The most rapid rate of movement of longwall faces in Germany is 6 ft. per day. In the ordinary hand-loading mine in western Pennsylvania break lines on full retreat will move about 2 ft. per day. If loading machines are used under similar conditions the, rate of retreat may reach 4 ft. per day. In a mine where coal is loaded by hand on conveyors three shifts per day, the rate of retreat has ranged from 11 to 16 ft. per day, with an average of 13 ft. If mobile loading machines could be used to load on con-veyors on break lines, the rate of retreat should be increased substantially.

Jan 1, 1938

By Virgil Miller, F. B. Petermann, S. F. Ravitz

The Cle Elum nickeliferous iron deposit is in Kittitas County, Washington, in a rugged, mountainous region about 23 miles north of the town of Cle Elum. The Biewett Pass deposit, which is similar in character and occurrence, is in Chelan County, about 18 miles east of the Cle Elum deposit. A more or less continuous ore zone may extend between the two deposits, since iron ore is reported to have been discovered at Iron Mountain, which lies directly between them. The ore probably was formed by meta-morphism of laterite resulting from Ieach-ing of serpentine derived from peridotite. It consists largely of magnetite grains distributed through a matrix of limonitic material containing a small amount of hematite and chromite. Many of the chromite grains have shells and inclusions of magnetite. The magnetite grains range in size from 1200-mesh to 1/4-in., the average size being 48 to 65-mesh; the chromite grains range from 20 to 150-mesh. The gangue minerals are olivine and serpentine with a small, amount of chlorite, and appear both as very thin bands in the ore and 's minute fragments in the limonitic matrix. The nickel is present as minUte inclusions of a nickel silicate mineral within the magnetite and gangue par- ticles, varying in size from 1500 to about 280-mesh. Detailed analyses of 3000-lb. lots of Cle Elum and Blewett Pass ore are given in Table I. TABLE i.—Analyses of Ore Samples Per Cent Ore from Constituent cle Elum' Blewett Pass Cr....................... 2.23 2-12 Ni...................... 1.43 0.9s Fe...................... 52.9 41.4 SiOz.................... 5.6 13.4 CaO.................... 0.3 0.8 MgO................... 4-1 7-5 AI2O3................... 7.0 2.g P...................... 0.022 0.034 S....................... O.O1 o.oa Mn..................... I.I 0.4 Ba..................... nil co..................... o.oa 0.02 CU..................... 0.02 0.03 As...................... 0.03 Au..................... nil Ag°..................... O.58 Pt...................... ml Fe++.................... 8.9 5-9 Fe+++.................. 44-0 35-5 « Ounces per ton, 1 sr,cte,so,","&&$ally absent: B, W, M~, T~, V, ~i, Bi, Pb. Sb. Sn. Be, In, Hg. Zn, Zr. Cd. Preliminary Tests Attempts to beneficiate the ore by ore-dressing methods, including various 'cornbinations of sink and float, tabling, jigging, flotation, and magnetic separation, were consistently unsuccessful. A wide variety of roasting and leaching tests were made on both raw and reduced ore, but in most of the tests little or no nickel was extracted, and in none did the extraction exceed 50 Per cent. No nickel could be volatilized as the carbonyl. by treating reduced ore with carbon monoxide. Fairly good sepa-

Jan 1, 1944

By Constantine Michalopoulos, Roger C. Van Tassel

Commercial demand for gold in the United States is important. It has a large impact on the total world commercial and overall non-monetary demand. Given the present free market price and our need to import gold, it has a substantial adverse effect upon our international payments position. But, according to most recent estimates, the United States demand is perhaps no more than 20% of the world as a whole. In 1971, United States consumption was estimated at 215.6 tons out of a total of 1,412.1 tons 1. This figure is very close to the 16% figure developed by Consolidated Gold Fields as the average for the years 1968-1970.2 Surveys of both production and use of gold on a world-wide basis are not new. With the bulk of gold production in only a few countries, it has been possible to develop fairly reliable series on gold output. Estimates have been developed on the known reserves of gold and probable output at various prices.3 On the demand side, figures have been somewhat less complete and reliable. The Bank for International Settlements and the Director of the United States Mint have regularly published estimates of commercial use in major industrial countries. The IMF has issued an increasingly comprehensive survey in its Annual Reports. The IMF has attempted to cover all nations-not restricting its efforts to major industrial nations-and has tried to estimate both gold taken for commercial uses (Estimated Industrial and Artistic Use) and for private hoarding. Their method is to begin with data on free world output plus any net sales by the Soviet Union, subtract any additions to world monetary stocks (or add to available supply for any net reductions in world monetary stocks), subtract estimates for commercial demand and have left as a residual an estimate for private hoarding. The method is straightforward and simple but the quality of the data is suspect. Industry sources tend to believe the figures as biased on the low side because of a persistent tendency to underreport gold movements.4

Jan 3, 1974

“The mining industry can do more to alleviate world poverty, hunger and human misery, more to close the widening gap between advanced and developing nations and more to achieve international peace and understanding than any other single force in the world," Charles W. Court, Minister for Industrial Development, Western Australia, told the American Mining Congress audience at the opening session of the 1969 Mining Convention, October 19-22, San Francisco. Australia, he pointed out, is a shining example. In 1971, 60% of U.S. mining investment overseas will go to Australia and other parts of Oceania, an increase of 42% over a year ago. Australia has capitalized on world needs, its own rich resources and good investment climate. Developing nations can and should do the same, but they mix emotion with nationalism, often frightening away foreign investment which could breathe life into dormant and backward areas, said Court.

Jan 12, 1969

By R. L. Tobie

Handling and storing ore at transfer points underground are encountered frequently. An ideal solution to these troubles is probably still to be found, but at the Mather mine "B" shaft a method incorporating scraping trenches has been developed giving better service, from the standpoint of safety and simplicity, than obtained from other schemes. When shaft pockets are used for storage, the size of the ground opening required to assure capacity is often prohibitive, and shaft depth below the last level can become excessive, particularly if a crushing station is used. Also, if the material being handled contains large amounts of wet fines, it is difficult, if not impossible, to hold the material with regular chute gates. In order to remedy these problems Cleveland-Cliffs' Mather "B" has utilized three types of trenches. Types I and I1 are now in service and the third is under construction.

Jan 4, 1955

By O. Hall

DIAMOND drilling has become a very important factor in mining. It is the most satisfactory method of obtaining proof of the existence of an orebody and of determining the character and extent of the body, in measures where a core can be made. Large investments are based on the information obtained. The method of development, the mine and reduction plants, and subsidiary essentials as railways are often built without other information. The Mond Nickel Co. has drilled about 50,000 ft. (15,240 m.) per yr. for several years and has given considerable study to the question of improving the methods and of overcoming the limitations of this means of securing information. One of the main limitations of the diamond drill has been its inability to drill a straight hole. To depths of 1000 ft. (304 in.) the deflection is often not large but all holes tend to curve and take somewhat erratic courses. A hole running at a small angle to a fissure plane tends to run, along the fissure. If the hole is at a large angle, the tendency is to penetrate the fissure plane at right angles. The face of the bit having one side in solid formation beyond the fissure, the other in the selvage of the fissure tends to turn, the rods curving to the extent of their clearance in the hole. Usually rock measures have somewhat regular fissuring or strata and holes take somewhat similar courses, usually at right angles to the fissuring or strata. Excessive pressure or short or worn core barrels increase curvature. Slow speeds, correct feeds, sharp hits, and core barrels the full size of the hit, tend to decrease curvature but do not prevent it Curvature once started increases rapidly. The disappointments from crooked holes have been numerous. Discoveries have later been found to be on the properties of others. One Canadian company had a hole, supposedly discovering ore 300 ft. (91 m.) from old workings, unexpectedly turn in 8 ft. (2.4 m.) of wooden core from a timber in the old workings.

Jan 9, 1919