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By M. N. Short

It is almost self-evident that the student of geology depends for his education in geology only in small measure upon his own observation. His chief sources of information are lectures and personal instruction from teachers, and the geological literature. Of these, the literature is by far the most important. The total geological knowledge available to the geologist of today is substantially that which is on the printed page, and no more than that. There are many geologists of outstanding rank who during the course of a busy and useful professional career have accumulated valuable geological knowledge. This, however, is never available to the profession, owing to the disinclination of these geologists to write or to the refusal of their employers to allow the results of their work to be published. With the passing of these geologists, their accumulated knowledge is irretrievably lost. In many mining districts the operating companies are not averse to the publication of geological information gathered by their engineering and geological staffs, but for various reasons this information is not published. However, when a public survey geologist goes into the district this information is placed at his disposal and eventually is published. But for the intervention of a disinterested public scientist, this information would have been buried in company files. In the last analysis, the teachers themselves depend largely upon the printed page for the knowledge they pass on to the student. Without geological literature, then, the instruction of geological students would be almost impossible. There is no .question that, as a whole, geologists who are on the public payroll have to their credit far more contributions to literature than have either teachers or professional geologists, whether the latter be independent or in the employ of private corporations. The very fact that geologists are upon the public payroll places them under obligation to make available to the public the results of their endeavors. They must either prepare these results for publication or they must furnish data or otherwise aid their colleagues to publish their results. The success or failure of a public geological survey depends entirely on the

Jan 1, 1935

By M. N. Short

It is almost self-evident that the student of geology depends for his education in geology only in small measure upon his own observation. His chief sources of information are lectures and personal instruction from teachers, and the geological literature. Of these, the literature is by far the most important. The total geological knowledge available to the geologist of today is substantially that which is on the printed page, and no more than that. There are many geologists of outstanding rank who during the course of a busy and useful professional career have accumulated valuable geological knowledge. This, however, is never available to the profession, owing to the disinclination of these geologists to write or to the refusal of their employers to allow the results of their work to be published. With the passing of these geologists, their accumulated knowledge is irretrievably lost. In many mining districts the operating companies are not averse to the publication of geological information gathered by their engineering and geological staffs, but for various reasons this information is not published. However, when a public survey geologist goes into the district this information is placed at his disposal and eventually is published. But for the intervention of a disinterested public scientist, this information would have been buried in company files. In the last analysis, the teachers themselves depend largely upon the printed page for the knowledge they pass on to the student. Without geological literature, then, the instruction of geological students would be almost impossible. There is no .question that, as a whole, geologists who are on the public payroll have to their credit far more contributions to literature than have either teachers or professional geologists, whether the latter be independent or in the employ of private corporations. The very fact that geologists are upon the public payroll places them under obligation to make available to the public the results of their endeavors. They must either prepare these results for publication or they must furnish data or otherwise aid their colleagues to publish their results. The success or failure of a public geological survey depends entirely on the

Jan 1, 1935

By H. E. Nold

THIS paper is an effort to explain in a simple manner the fundamental principles involved in examining a clay deposit for both quantity and quality and in operating a clay mine, either open-pit or underground, SO that the best quality of finished material can be made from the raw material available. The writer is aware that what is recommended in this paper is everyday practice in many refractories plants and in some other heavy-clay products plants, but observations made while visiting practically every clay mine in Ohio have convinced him that the practices herein discussed are not as widely used as their importance warrants. It is true that the problem of mining for quality is more acute in refractories plants than in most heavy-clay products plants, yet some of the latter are finding it profitable to pay more than ordinary attention to the selection and blending of their raw materials. It is hoped that this short paper may prove helpful to some who are now finding it difficult to produce a uniform product of as high quality as their clay deposit seems to warrant. The coordination of the work of the clay mine or pit with the manufacturing plant, to the end that the best product possible be made from the raw material available, presupposes a rather intimate knowledge of the clay deposit. The knowledge must include not only information of the amount of clay available but also rather detailed information about both vertical and horizontal variations in quality of the clay. This information should cover three things: quality, quantity, and location. Sampling Undeveloped Deposits In the case of an undeveloped deposit with a shallow overburden, pitting may be the cheapest way of testing. For thick deposits or deposits with rather heavy overburden, the diamond drill, using a double core barrel, offers the best means of testing. When using the diamond drill in clay testing, it is doubtful whether it pays to take less than 2-in. cores; it is difficult to get complete cores with smaller drills, and the quantity of material obtained with smaller cores is not sufficient for the necessary tests.

Jan 1, 1929

By W. E. Wickerham

THE Magnetic Storm Monitor is an instrument that continuously records variations in the earth's total magnetic field at a fixed location. It is intended for use in conjunction with airborne magnetometer surveys. There are stormy periods when changes in the earth's magnetic field are so violent that data obtained with airborne equipment would be of little value. The Monitor provides this information so that flights may be cancelled or terminated, thus eliminating useless flying. Moreover, when some unpredictable change in the earth's field occurs during an airborne survey, the Monitor record, showing a similar event, may serve to salvage the data. The utility of a base instrument is determined largely by its physical dimensions, power requirements, stability, and reliability. This instrument is small enough to be transported in any powered vehicle. It will operate from either a 110 v, 60 cycle power line or from an inverter powered by an automobile battery. The development of an electronic feedback circuit that measures the magnetic field strength and a fabricated buckout magnet having essentially zero temperature has contributed to instrument stability and reliability. A tripod supporting the magnetometer head, a chassis housing all electronic components, and an Esterline Angus Recorder comprise the equipment, shown in Fig. 1. The vibrator-type inverter shown is used when a 110 v, 60 cycle power line is inaccessible. Approxi- mately 60 w are required to operate the instrument and the circuit is insensitive to reasonable power line voltage changes or transients. The head unit contains a fluxgate-type magnetometer element and a special magnet mounted on a ceramic structure. Since this magnet is used to buck out most of the earth's field, adjustments are provided for properly positioning the magnet with respect to the element. This assembly is mounted in such a way that the element can be oriented into the total field. Fluxgate Element: The heart of the Storm Monitor is a fluxgate-type magnetometer element. The ability of this unit to detect changes in magnetic fields has been covered at length in the literature.1, 2 For this discussion it will suffice to say that the Gulf

Jan 1, 1956

By Norman L. Newbern, Robert E. Green

An investigation of the effect of size on the deformation properties of metal single crystals made it desirable to grow from the melt cylindrical aluminum single crystals possessing exactly the same crystallographic orientation but varying in diameter. Methods for the growth of rather large (up to 3 in. diam) aluminum single crystals in molds of the desired shape are well known. However, when one applies the same techniques to the growth of smaller (less than 1/8-in. diam) specimens many additional problems arise. Two of the major problems are the construction of the molds to be used and the removal of the thin specimens from these molds without deformation after growth has been completed. Also the problem of the constraint forces exerted by the mold on the specimen is much more pronounced for the smaller specimens. The technique described herein is a zone-melting method in which no mold is used since the surface tension of the molten metal and its oxide is sufficient to retain the melt. The specimen is suspended vertically in a manner similar to that of Keck and Golay.2 However, while Keck and Golay supported the specimen from both ends, the method used here supports the specimen only at the upper end. The surface tension of the molten aluminum and aluminum oxide contains the melt and suspends a length of newly grown crystal that has already passed through the molten zone until the weight of the newly grown crystal is equal to the component of surface tension holding the specimen together in the molten region. When the weight of the newly grown crystal is equal to the component of surface tension holding the specimen together the specimen pulls in two in the molten zone. The length of crystal which can be grown before this separation occurs varies with the diameter of the specimen and the size of the molten zone. In order to prevent the specimen from pulling in two a tube of glycerine is placed beneath the furnace in such a manner that the newly grown crystal passes into the glycerine which provides sufficient buoyancy to allow aluminum single crystals in wire form to be grown to lengths determined only by the length of the tube containing the glycerine. A schematic diagram of the experimental arrangement is shown in Fig. 1. The furnace used is constructed as follows. High-resistance nichrome wire is coiled on a 3/8-in. diam fused quartz tube. The distance between the windings is much less over a length of about 3/8 in. at the center so as to develop a hot spot. This core is located in the center of a 4-in. diam steel cylinder 5 in. in height and insulated from it by Kayolite. The temperature of the furnace is controlled by means of a thermocouple located near the central hot spot and a Minneapolis-Honeywell temperature controller. Temperature ins,ide the furnace is measured with a thermocouple and a standard potentiometer in the usual manner. By the above method it is possible to grow high-purity (99.99 pct Al) aluminum single-crystal wires over a range of sizes. Crystals varying from 1/8 to 1/64-in. diam were grown by the authors. Since the tube containing the glycerine cannot contain a crystal longer than approximately 3 ft, the growth of crystals longer than this presents another problem. It was found that one could cut the newly grown crystal without deformation in the region between furnace and glycerine tube try means of a cutting torch and then by moving the glycerine tube slightly aside continue

Jan 1, 1962

By Dermot Ross-Brown, Brian Stimpson

The use of point load test data by the authors to estimate rock mass cohesion is a very ingenious approach. It must be emphasized that this estimate is indeed only an estimate since the point load strength index employed to predict the uniaxial compressive strength (and subsequently predict the cohesion) is likewise only an estimate.

Jan 11, 1979

By Howard Drullard

To OBTAIN the best results from hammer drills, close attention must be paid to two factors in drill maintenance, which are of equal importance; one is lubrication, the other is the shank. With the exception of stoping drills, most modern rock drills require both oil and grease. The oil ports are in the lubricator, on or behind the hammer cylinder; the grease port for the lubrication of the 'chuck sleeve and rotating mechanism is on the chuck end. Ordinary machine oil is not, adapted to rock drills; a heavier more gelatinous oil such as castor machine oil or liquid-grease should be used. The lubricators should be filled-once for every 12 or 14 ft. (3.5 to 4m.), of hole drilled. Grease-guns should be used to fill the port in the chuck end once a shift; a medium ( No. 3) grease is well adapted to this purpose. Hard grease must not be put into- the lubricators, as it will not flow through that part. Contrary to the popular belief, oiling a machine once or twice a shift does not provide sufficient lubrication; the drills should be oiled once for every 12 or 14 ft. of, hole drilled. The rotating handle of a stoping drill -is an oil reservoir and is provided with a port for oiling. The rotating handle is packed with wicking, or similar material, which causes the oil to feed slowly from the handle to the other parts of the machine. Stoping drills require oil at. least twice a shift; lighter oils than castor, such as Arctic Ammonia may be used.

Jan 8, 1920

By Fred C. Bond

THE process of comminution by grinding is properly classified as an art, rather than as a science. Like most other operations concerned in ore dressing, or in the treatment of nonmetallic minerals, the mathematical relationships of rock breaking are still obscure, and much disputed. If some basic formula exists, comparable for instance to E = RI in electricity, it has not yet been placed in, common use. The absence of such a comprehensive mathematical background undoubtedly is the cause of many inefficient designs and installations, as well as of much poorly oriented experimental work. On the other hand, the mathematical immaturity of the process constitutes an opportunity for a real contribution on the part of those who enjoy mental pioneering. Some of the statements made in any such exploratory work may be little more than opinions, and it is to be expected that some will later be proved untrue; but such an evolutionary development is necessary if we are ever to arrive at the fundamental laws, the discovery of which can change the empirical art into a mathematically exact science. The most significant principle of comminution that we possess is probably Rittinger's law, which states that the work done in crushing or grinding is proportional to the area of the new surface produced. There is an alternative theory, known as Kick's law, which formerly was preferred to Rittinger's but which now is rather discredited. According to Kick, the work done in comminution is proportional to the volume, or weight, of the pieces broken, or to the cube of their diameters, while according to Rittinger it is proportional to the square of the diameters. Careful determinations of size distribution below the limit of sieve sizes1 indicate strongly that under ordinary grinding conditions the amount of new surface area produced is directly proportional to the net power input. Changes in the size ratio between the balls and the particles cause important differences in the proportion of the product that passes a given mesh size, but do not affect the total amount of new surface area; they merely change the distribution of the surface among mesh sizes. The principle of constant surface area is the logical result of Rittinger's law, and it may well have an important bearing on the comminution theories of the future. FORMULA FOR BALL WEAR Grinding tests have been made in the Allis-Chalmers laboratory for more than 9 years, using a standard charge of mixed balls of different sizes; and a continuous record has been kept of the rates of wear of each size. These results have been combined and plotted in various ways in order to discover the relationship that exists

Jan 1, 1940

DeLamar, the largest silver mine in the United States outside the Coeur d’Alene District in Idaho, came into production in April 1977. It is a joint venture of Earth Resources Company and Canadian Superior Oil Co., with Earth Resources being the operator. The property is a consolidation of several old operations dating back to the 1800s; the better known of these are the DeLamar and Sommer-camp mines. DeLamar is situated in southwestern Idaho near the Oregon border in the Owyhee Mountains, 88 km (55 miles) southwest of Boise, Idaho. Heavy snowfalls and very low temperatures are common in the wintertime. Planned production was 77,500 kg (2.5, million oz) of silver and 5 13 kg (16,500 oz) of gold per year. Expected life at a milling rate of 1,540 mtpd (1,700 stpd) was 20 years, with an ore grade of 144 g Ag and 1.58 g Au per mt (4.2 oz Ag and 0.046 oz Au per st). Present production is at the rate of 1,900 mtpd (2,100 .stpd). The total cost to bring the mine into production was reported to be approximately $22 million, and the mill was reported to have cost about $10,000 per daily ton of design capacity. At DeLamar, naurnanite (Ag2Se) is the principal silver .mineral occurring with acanthite (Ag2S) disseminated through quartz veins and a silicified rhyolitic ash-flow tuff of Miocene age. The mineralization is relatively iron and manganese free and is readily amenable to cyanidation giving recoveries of 85% silver and 92% gold, which occurs free. When the plant was started, considerable difficulties were encountered in handling the wet sticky ore because of the high clay content. Following primary crushing, the ore is stockpiled. Due to the sticky nature of the ore, the vibrating feeders initially installed under the stockpile were replaced by a reclaim hopper and an apron feeder which was fed 24 hours a day by a front-end loader. The minus 200 mm (8 in.) ore is fed to a 5.5 m by 2.75 m (18 ft by 9 ft) autogenous mill followed by a 2.75 m by 4.57 m (9 ft by 15 ft) ball mill and cyclones. The mills are equipped with 750 kw and 520 kw (1,000 hp and 700 hp) motors. Both mills discharge to the same cyclone feed sump and a portion of the cyclone underflow is returned to the autogenous mill. Cyclone overflow, which is 20% plus 74 microns (200 mesh), is leached in four agitators in series for 72 hours (45 hours at the 2,100

Jan 1, 1981

As a service to its readers, MINING ENGINEERING is publishing the mineral industry portion of the 1952 list of "Accredited Undergraduate Engineering Curricula in the United States." This list, revised annually, is issued by the Education Committee of the Engineers Council for Professional Development, and covers all phases of engineering education. The AIME is actively represented on ECPD, which was jointly organized by the Founder Societies and various other groups interested in the professional recognition of engineers.

Jan 4, 1953

By Clement K. Chase

The ammonia leach for copper recovery is discussed from historical and current practice standpoints. The chemistry of the system is presented together with Eh-pH and copper-ammonia solubility curves. A list of metals forming ammine complexes is presented. The advantages and disadvantages of the ammonia leach as applied to copper recovery in conjuction with modern liquid ion exchange techniques are compared.

Jan 1, 1980

By W. E. Coughlin, R. L. Faverty, F. H. Lightner

The intent of this paper is to present the general strategy and method of implementation to achieve a "fast-track" mine development. The major objectives of a "fast-track or rapid development schedule are to minimize front-end development expenditures and to realize an early cash flow from operations. The Borealis project of Houston International Minerals Corp. (HIMCO) is used as the working example to illustrate the development schedule. Borealis is a 2.9 kt/d (2,500 stpd) gold-silver heap leach operation near Hawthorne, NV.

Jan 1, 1984

THIS issue is about Chuquicamata and the new sulphide plant. Chuquicamata is moving into a new cycle of productivity; she has begun to give up the sulphide copper which lies deep-seated beneath the oxide ore zones in large but yet unknown quantity. After forty years of production, Chuqui may be likened to a strapping youngster, with adolescence and maturity still ahead. Mining operations are being projected-not for decades -but for generations. Although there are still many years of open-pit mining ahead, planning of future underground mining has been started. The bottom of the orebody is still unknown, but enough work has been done to show that Chuqui is one of the largest known copper orebodies in the world. Until recently, only the oxide ores have been mined and these have been treated at the rate of 50,000 to 60,000 tons per day by leaching. Construction of the sulphide plant was timed to coincide with reduction in production of oxide ores. The new sulphide concentrator and smelter, designed in keeping with the magnitude of the orebody, will be brought on the production line at the rate of 30,000 tons per day. The capacity of the plant now planned can be expanded to treat 60,000 tons of sulphide ore. Little wonder that Chuqui is a name legendary in the remotest mining circles. But to those who have known her more intimately, and there is hardly a mining camp without a Chuqui graduate, she means much more. She is an orebody that has made engineers. Reposing at 10,000 ft on the western flank of the Andes in the arid northern reaches of Chile, water is scarce, common fuels absent, and volcanoes and earthquakes add drama and hazard. It is these natural difficulties which have created the fascination and challenge which have caused many engineers to devote their lives to unlocking this treasure house of nature.

Jan 1, 1952

By A. J. Strane

PRACTICALLY all explosives may be classified as those that burn and those that detonate. Explosives of the first class include .black blasting and smokeless powder and are broadly known as low explosives, or propellants, because they merely burn and do that comparatively slowly. Their action is as if some power behind the projectile or other material were exerting a shoving or pushing action. The high, or detonating, explosives produce a smashing or shattering effect upon the material. In using military- explosives of the propellant class, the breach of the gun, or cannon, is proportioned to hold the pressure, so that the projectile will be blown out. Exactly the reverse is true in commercial work; then it is the "breach" or the hole that is to be broken. The projectile and the explosive are therefore chosen that will rupture the largest "breach" possible. With the high explosives, it is easy to break out the breach (that is why they are of no value as military propellants)" but with some of the low explosives it is necessary to plug up the muzzle very carefully before shooting. Doubtless the use of incendiary mixtures of oxidizing and combustible materials led, in the 13th century, to the perfection of the mixture which is practically the same as our commercial black blasting powder of today. About 600 years later, nitroglycerine was discovered, but for years its great potential energy could not be used because, in its liquid state, it could not be safely handled or transported. The accidental discovery that kieselguhr would absorb, and hold fairly well, three times its own weight of nitroglycerine, however, made it available. "Guhr dynamite," as the combination nitroglycerine and kieselguhr was termed, was soon displaced by dynamites having an active base, such as wood pulp and other carbonaceous combustible materials. These do all that kieselguhr will do and, in addition, increase the chemical reaction and add materially to the effectiveness of the blast.

Jan 8, 1920

By H. De Cizancourt

Peche1bronn.—So far Pechelbronn is the only producing district. Figures are given in Table 2 covering the main features of the field, but these figures call for the following remarks: First, Pechelbronn should not' be considered as a single unit, it appears, but as a succession of small oil fields, each of which is affected by very variable conditions. Consequently, certain figures concerning production per acre, production per acre-foot, pressure conditions and thicknesses of oil sands would be so misleading that they have been omitted here. Second, as regards production methods, attention is drawn especially to the fact that 42 per cent of the oil is extracted by the use of shafts and galleries and the remainder by pumping wells. Exploitation, formerly confined to Oligocene sands, has been extended recently to Jurassic and Triassic oil-bearing formations. Gabian.—This small oil field, discovered in 1924, is almost exhausted. Exploitation to date is restricted to three wells. There were no drilling activities in 1933. Exploration.—During 1933, two exploration holes have been started in France. The first, in the vicinity of Lavelanet (Ariége) on the Dreuille anticline, has reached the depth of 2400 ft,.; the second, in the Autun Permian Basin, is drilling at 1300 feet. Northern Africa Morocco.—Drilling operations have been on a large scale in Morocco. In the Gharb district (Souk el Arba area), the deepest well was abandoned in 1933 at 7014 ft. Small irregular productive horizons were encountered in the Miocene at shallow depth, oil and gas showing in the Eocene, but no commercial oil field has been discovered. In the Djebel Tselfat, near Petitjean, a small production of oil was obtained from a Jurassic horizon. In the meantime deeper formations are being explored and a new structure in the vicinity is being tested. In Eastern Morocco, a well is drilling near Taza. Production in Morocco, about 2400 bbl., has not been listed on Table 2, owing to its origin—exploration wells.

Jan 1, 1934

By Roswell Johnson

THE principle of sliding or graduation in royalties is accomplished either by the block, period, cumulative, or class method. The block method calls for a very low royalty rate on all oil produced up to. a certain amount. This amount would normally be that which is believed to suffice to repay the cost of the well. A higher rate would be charged after the well is making a profit. This method, common in many industries, is peculiarly inadaptable to any industry such as this where the productivity per day of the units gradually and inevitably decreases. This, for reasons given later, is because it forces an early abandonment of the well and so offends against conservation. In the period method, the royalty rate is changed by some definite amount when the well produces less than a specified quantity per day or other given unit of time. While simple to explain, it operates badly because a great deal is made to depend upon a small reduction in production, whereas the reduction as a matter of fact declines rather erratically owing to the exigency of lease management, connecting of tankage, and vagaries of the gaugers. These disadvantages are obviated by the cumulative method. In this method, all the production less than a certain amount per week has one rate of royalty, or none at all, and the oil produced in excess of that amount pays an additional rate of royalty. In the long run the calculation is probably no greater than with the period method, for simple tables will be published and printed in the oil papers that can be cut out, enabling quick readings to be made. Even without the table the calculation is easy with the few royalty rates, two or three, which would be used. In this method, the amount paid in royalty declines gradually, rather than suddenly as in the period method.

Jan 6, 1915

In accordance with the provision of the Constitution, notice is here given to all Members, Associates and Junior Members, that the dues of the year 1917 will be payable on Jan. 1, 1917, at the office of the Secretary. The dues for Members and Associates are $12 per year and the sum of $3 additional is asked of those Members and Associates who desire to have the three volumes bound in the Institute's standard half morocco binding. The dues of Junior Members are $5 per year. Volume 54 of the Transactions is now printed, and will he sent in January to all members whose dues for the year 1917 are paid.

Jan 12, 1916

Announcement is made that applications fir the Emmons Memorial Fellowship in Economic. Geology will be considered, and an incumbent appointed prior to the first of June. Applications should be sent to Professor J. F. Kemp of Columbia University not Intel: than May 15. . The holder of this fellowship receives an income of $1,000 and is expected to carry on an investigation in Economic Geology which will add a distinct contribution to the literature. The institution at which the study is pursued will be decided after conference with the members of the Committee of Awards. The character of the investigation will be decided after applications have been passed upon.

Jan 5, 1917

An ore search for commercial titanium-bearing ore deposits is in progress by the Crane Co., manufacturers of valves, because they expect this metal to be important in valve manufacturing in the future. The company will eventually be mining and making titanium sponge. At present they are buying titanium tetrachloride from the Stauffer Chemical Co, at Niagara Falls and making titanium by reaction with magnesium. Production from the Babbitt concentrator of Reserve Mining Co. is scheduled to begin in late 1951 or early 1952. The capacity is to be 300,000 tons of pellets per year made from magnetic taconite concentrates.

Jan 7, 1951

By O. Skiredj, J. F. Elliott

It has been necessary to collate the available data on the solubility of graphite in Fe-Si-Mn alloys for a study of slag-metal equilibria in ferromanganese production. That study will be reported later; the collation is reported here. The carbon content of graphite-saturated liquid iron above 1153ºC by Chipman and co-workers1 is: %C= 1.34 + 2.54 x 10~3t(°C) [l] For graphite-saturated manganese above 1322ºC it is: %C = 2.68 + 3.52 x 1CT3 t(°C) [2]

Jan 1, 1963