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By Sebastián Seria, Jorge Álvarez, Diego Cáceres

The capacity to break the rock into adequate size fragments and in a cost-effective way is one of the main challenges in large open pit copper mines in Chile. That capacity is often compromised by the accuracy of geological estimations and the resources allocated by the mine site to update those models, making the blasting design highly dependent on that input and in consequence, blasting results. Given these opportunities, having an alternative method to input estimated key geological parameters allows blast designers to modify their designs and apply the appropriate energy to achieve the desired results. By using measurement-while-drilling data from boreholes and a few samples of actual, widespread, hardness measurements on site, we can deliver an updated cost-effective hardness estimation that is used as an input to improve the blasting design and its results on fragmentation. This estimation is delivered as a hardness interval – often in MPa units- related to the position of actual drilling measurements. In addition, having a sufficiently large drilling dataset allows us to predict hardness in new, undrilled areas near already measured boreholes, serving as a prior estimation available before pattern design. The use of these estimations, applied to several copper mines in Chile, allow us to more accurately determine explosive amounts and borehole drilling, which directly contributes to more productivity and efficiency in mine site operations. The results are often related to narrowing the gap for fragmentation results, even so, in some cases that will be related to direct savings in Drilling & Blasting process in a range 5-10% of the budget, due to powder factor changes.

Jan 26, 2026

By Hung-Ming Chen

This paper presents a Cloud-based system framework for providing a web-based building information model (BIM) service. Cloud computing technologies were used to develop a BIM data center, which can handle the big data of massive BIMs using multiple servers in a distributed manner. In addition, the system allows multiple users to access the BIM data center online to submit and review BIMs concurrently. In this study, the advanced technologies/tools of web development and Cloud computing were applied and incorporated to develop a prototype system, named CloudBIM. On the client side, this study applied WebGL and HTML5 in the web-based interface development to achieve the 3D display of BIMs and the dynamic interaction with viewers through browsers. Users can access the services of CloudBIM by using PCs, laptops and tablets anytime anywhere to view the 3D model via browsers, which support WebGL. On the server side, this study used Apache Hadoop, an open-sourced distributed file system based on Google?s technologies, to establish a BIM data center. The Hadoop Distributed File System (HDFS) can utilize multiple servers to provide mass storage spaces in a distributed manner. Based on the use of Apache HBase, which provides Bigtable-like structured storage for HDFS, this study proposes database schema for storing the information from massive BIMs in two bigtables, named Object table and Property table respectively. In addition, Hadoop MapReduce, a Hadoop component for the parallel processing of large data sets, is utilized for model data acquisition by parsing the IFC files of uploaded models in parallel.

Aug 1, 2013

By K Williams

Marvel Loch South Pit has had a number of stages of open and underground mining activities before acquisition by Sons of Gwalia. The historical pit had achieved a completed pit depth of 150 metres and the shaft and decline mine had reached approximately 220 metres in depth using open stope mining methods. The various mining methods reflect the various economics and industry practice at the time. The South Pit ore zones are medium grade (~2.5 g/t) but have a regular geometry and large tonnes per vertical metre. A number of studies have been completed up to a pre-feasibility stage looking at options to extend the pit depth and to lower the unit cost of gold production. The options considered were the re-optimisation of the pit to determine further cutbacks or the innovative use of an in-the-wall ramp. The in-the-wall ramp (tunnel) would permit the removal of the in pit ramp to expose additional ore that was within the footprint of the ramp design and to provide the opportunity to increase the final pit depth. Similar mining method has only been used at Three Mile (Coolgardie, WA) and Chalice Mine (Norseman, WA). The tunnel would serve as a gateway for further extension of the south mine and the central ore zone via underground mining methods. The ultimate depth of the South Pit has been extended to 310 metres below surface and significant additional ore has been recovered. This paper will give an insight into the various studies to optimise the Tunnel mining method, the determination of the various tunnel dimensions, and the phases of mining to arrive at the completed design.

Jan 1, 2003

By W. J. Feuerstein

STRUCTURAL imperfections in crystals, in recent years, have received the attention of metallurgists concerned with single-crystal properties. Certain etching solutions cause local variations in the rate of etching at dislocations.' Dislocations are expected to be preferred segregation sites for impurities' and Dash" has shown that precipitation of copper occurs preferentially at edge-type dislocations in silicon. Diffusion rates along dislocations are probably higher than rates through more perfect crystalline regions.' These and other phenomena which may be influenced by dislocations may be studied by revealing dislocations as etch pits. This study was undertaken to develop an etch solution for silicon crystals to reveal low-angle grain boundaries associated with dislocation arrays and also etch pits with good contour definition. Additional etches have been reported by Dash," Vogel and Lovell.T rystals were sectioned on crystal lographic planes at various angles from the growth direction for microscopic examination of the etch pits. Experimental Crystals of 75-100 g mass and 3 cm diam were oriented and cut on crystallographic planes. Crystals were grown by Czochralski technique from a quartz crucible. Lapped wafers were chemically polished in a modified CP-4 etch for 1 min (bromine was deleted from the etch solution). The polished wafer was then etched* at room temperature for 5 min. The use of larger amounts of H2O and/or CH2COOH slows the reaction. The Cu(NO3),.3H2O was added to increase the reaction rate and give more definition to the etch pits developed. Some pertinent features concerning the attack of this etch on silicon can be summarized as follows:

Jan 1, 1959

By E. J. Schmitz

The mining of the Triassic coals of the Richmond basin has been carried on, upon a larger or smaller scale, for more than a hundred years. Notwithstanding the close proximity of the field to a large city and to tide-water, assuring both a good home-market and cheap transportation, and notwithstanding the good quality of the fuel and the great thickness of the principal bed developed and worked, operations in this field have been conducted with but limited success. The basin comprises about 189 square miles, being from 24 to 31½ miles in length by 5½ to 10 miles in width. Not much more than one-tenth of this area has been explored in a practical and efficient way, and not over 1200 acres have been worked near and along the outcrops or edges of the coal. The practical mistakes which have been committed undoubtedly in a number of the mine-operations of the past, do not alone explain the unsatisfactory success and progress of the industry of this field ; nor can it be ascribed to the lack of local enterprise. Other reasons have to be looked for; and, as a principal one, the irregularity and the faulted conditions of the coal deposits must be pointed out. As a second cause, the indifference of the State government, which leaves the development of the field entirely to private enterprise, instead of aiding it by systematical and practical geological investigations, deserves to be mentioned. Nothing has been done by the State since the excellent work done more than fifty years ago by Professor Rogers, who could not at that time enter into the details of such

Jan 1, 1895

By Robert M. Yerkes

The following is a brief account of the methods of measuring intelligence especially prepared for use in the U. S. Army, of typical results, and of some of their immediately practical applications. It has been prepared for the assistance of army examiners and for the information of all who are interested in the relations of scientific placement to military efficiency. Purpose of the Intelligence Tests Under the direction of the Division of Psychology, Medical Department, and in accordance with provisions of War Department General Order No. 74, mental tests are given recruits during the 2-wk. detention period. These tests provide an immediate and reasonably dependable classification of the men according to general intelligence. Their specific purposes are to aid: 1. In the discovery of men whose superior intelligence suggests their consideration for advancement; 2. In the prompt selection and assignment to development battalions of men who are so inferior mentally that they are suited only for selected assignments; 3. In forming organizations of uniform mental strength where such uniformity is desired; 4. In forming organizations of superior mental strength where such superiority is demanded by the nature of the work to be performed; 5. In selecting suitable men for various army duties or for special training in colleges or technical schools; 6. In the early formation of training groups within regiment' or battery in order that each man may receive instruction and drill according to his ability to profit thereby; 7. In the early recognition of the mentally slow as contrasted with the stubborn or disobedient; 8. In the discovery of men whose low-grade intelligence renders them either a burden or a menace to the service.

Jan 1, 1919

By Edward Keller

In order to conduct intelligently the sampling of copper of various forms and grades, solid or in molten furnace-charges, a knowledge of this subject is essential. Yet figures and tests have been persistently withheld from publication, and the books at our command give us little or no information in this regard. This gap in our copper-literature has led to a series of experiments, the results of which are given below. Nearly all gold- and silver-bearing copper, destined for shipment, is cast into the form of bars or pigs. For the sampler, the question arises, Does copper, so cast, remain homogeneous ? If it does, sampling should present no difficulties; but, from experience, we know that this is not the case, and we are thus led to study the behavior of the precious metals arid impurities in copper when the latter changes from the molten to the solid state. For the purpose of the experiments here described, all available grades of copper were selected, and all of them mere subjected to the same conditions, an important requisite for proper comparison. The molten copper obtained directly from reverberatory- and blast-furnaces was cast in a cast-iron mould, the sides and bottom of which were 1 inch thick, and would, therefore, give the copper a fair length of time to chill. The inside dimensions of the mould, and, consequently, of the block of copper obtained, were: length, 10 inches; width, 9 inches; and depth, 5 inches. Fig. 1 illustrates the method employed to obtain samples from these blocks. A was cut away, and the face so produced BALTIMORE COPPER WORKS,

Jan 1, 1898

By G. R. Speich

RECENT studies by Smith and Olney,1,2 Olney,3 Greifer and Salli,4 Rys etal., and Olney and smith 6 have established that graphite is the first decomposition product to format the surface of hypereutectoid plain-carbon steels when they are austenitized in a vacuum or inert atmosphere and slowly cooled. This graphite evidently forms directly from the austenite and only at the surface of the specimen. The interior of the specimen is found to be free of graphite. The graphite layer can almost completely cover the specimen surface and the rate of its formation is markedly sensitive to the orientation of the austenite. The present work was undertaken to study this phenomenon further, especially with regard to the effect of temperature and austenite orientation. The material studied in this work was a high-purity iron-carbon alloy containing 0.88 pct C, 0.005 pct Mn, 0.016 pct Si, 0.005 pct S, and 0.002 pct P. Specimens were heat-treated in a commercial hot stage modified for rapid quenching.7 This permitted direct observation of the formation of the surface graphite. A vacuum of 10"" to 10-5 mm of Hg prevented oxidation or decarburization of the specimens. Specimens were austenitized for 30 min at 1100°C and quenched to a series of lower temperatures where they were isothermally transformed. Surface graphite was observed to form at 700°, 750°, and 780°C but not at 825°, 900° or 1000°C. Since the maximum solubility of austenite for graphite is 0.88 pct C at 800°C,8 surface graphite only forms at tem-

Jan 1, 1962

By Arthur Taggart

FLOTATION of sulphide minerals and native metals is no longer a practical difficulty. The underlying scientific principles of the method, although not explored in anything like complete detail, have been formulated with sufficient breadth so that the direction of attack on any specific case is clearly indicated. It has been known since the earliest clays of flotation that certain of the nonsulphide nonmetal minerals-e.g., sulphur and graphite-would respond to flotation by oils as sulphides do; therefore they have been grouped with sulphides in many patents. But since the development of the chemical theory of collection,1,2,3 this similarity in action has been one of the facts cited in disproof of the theory by opponents of the hypothesis.4,5,6 Air levitation? of certain oxidized minerals, both metalliferous? and nonmetalliferous, and separa-tion thereby from other oxidized minerals, is a recent development in practice, although the discovery of the method dates back 17 years.7 This paper presents evidence that the principles underlying the air levita-tion of the nonsulphide nonmetal minerals are the same as those utilized in the flotation of the sulphides and native metals. It will be apparent immediately to anyone with knowledge of mineral concentration that separation of air-levitated minerals in water from minerals not so levitated is a simple matter of water-gravity concentra-tion, the separating device employed depending solely upon the size of the particles treated and the buoyancy differences effected by the levita-tion, The usual separating means employed are: (1) a flotation machine for fine, slimy and for well aerated granular material; (2) shaking tables for granular less aerated material.

Jan 1, 1937

By N. S. Kenny, A. A. Burr

THE purpose of this note is to present evidence that vacancies, which have been produced by quenching from a high temperature, alter the rate of strain-hardening of an hep single crystal. The majority of investigations of the effects of quenched-in vacancies on the yield stress of metals have been made using fee samples in the form of thin wires. However, there is an inherent disadvantage in using such wires to study the effects of vacancies on the rate of strain-hardening of metals because fee wires begin stage II slip either immediately upon yielding or very shortly thereafter. When stage II slip occurs, very rapid strain hardening also occurs, masking the effects of vacancies on the rate of hardening. In this investigation single crystals of magnesium hep were studied since magnesium has only one slip plane at low temperatures and has, therefore, an extensive easy glide region. In addition, the effect of both static and dynamic recovery on the rate of hardening were eliminated by testing in liquid nitrogen. Both forms of recovery occur in hep metals by dislocation climb, which is a diffusion controlled mechanism and is negligible at liquid nitrogen temperatures. Finally, the dependence of the strain-hardening rate on the crystal orientation was eliminated by using the equations of Schmid and Boas.' Variations in the strain-hardening rate could, therefore, be attributed to the presence of vacancies. Single crystals in the form of rods approximately 5 mm in diam and 6 cm long were grown by a modified Bridgman technique from commercial high-purity magnesium (99.97 pet) supplied by the Dow Chemical

Jan 1, 1962

By E. W. Schilling

THE separation of hematite by hysteretic repulsion was first brought to the attention of the public in 1922, by W. M. Mordey1. Three years later another paper2 was published and after another four years a third paper3 appeared in the South African publications. Certain data were lacking in these papers. In order to continue the work intelligently a knowledge of the shapes of the hysteresis curves for certain minerals was very necessary. This information was not available until the present year4. It was known that reduction of certain ores rendered them amenable to this process of separation but definite data in the form of curves showing exactly the effect of such treatment were lacking. Prob-ably our best source of information on the separation of minerals by the use of alternating-current magnetic fields today is the reports from the U. S. Bureau of Mines 5-7. It is not the purpose of this paper to tell the reader in detail how to make a commercial separator. Experimental models have recently been made 7 and the results obtained have been so good that it is the opinion of the authors that the public will soon take an active interest in the subject and its development. The writers have constructed a separator that is considerably different in construction and operation from the two types described by Mr. Davis. This will be described, but the real purpose of this paper is to outline certain experiments and give curves showing data that have a fundamental bearing upon the practical construction of a separator of this type.

Jan 1, 1935

The epithermal silver-gold Red Rock Deposit is hosted in the Late Permian inter- mediate to silicic composition Drake Volcanics of New England, N.S.W. This deposit represents one of the few low sulfur epithermal precious metal systems in eastern Australia, and differ! from epithermal models in that the hydrotherma: system which produced mineralization was active in a shallow water marine environment. The Red Rock Deposit has a resource of 180,000 tonnes of 66g/t Ag and 0.9 g/t Au, and a Ag:Au ratio of 70:1. Mineralization is largely associated with hydrothermal brecciation, and occurs as disseminations, vein stockworks, and struc- turally controlled lodes. Ore minerals comprise acanthite (argentite), electrum, native Ag, Ag- sulfosalts and base metal sulfides, Alteration minerals associated with ore are quartz, cal- cite, adularia, pyrite, illite, illite-mont- morillonite, chlorite and sphene (leucoxene). Illitic and propylitic alteration zones sur- round the hydrothermal breccia. Bulk rock analyses indicate that alteration is character- ized by the addition of Si, K, Fe, Mg and the loss of Na and Ca. Ore was deposited from a boiling fluid in a temperature range of 222- 295¦C, and of 0.5-7 wt. Z NaCl equivalent sal- inity. An upper hydrostatic depth limit of about 800 m is implied for the boiling fluid ii an open vein. Sulfur isotopes indicate a mag- matic sulfur source, and oxygen isotopes imply a predominantly marine ore fluid. Modern analogs of the submarine hydrothermal system that formed the Red Rock Deposit occur in the Taupo Zone, New Zealand, and southern Kyushu, Japan.

Jan 1, 1987

By Kim M

Mukuk gold mine in South Korea produces a pyrite concentrate containing gold associated with arsenopyrite as a gangue mineral. The effects of Portland cement as a depressant on the flotability of arsenopyrite were studied to improve the separation of arsenopyrite from pyrite concentrate containing gold. A series of the fundamental flotation tests were performed using Portland cement as a function of pH and concentration of the collector. Flotation recovery of pyrite and arsenopyrite in the fundamental tests with amyl xanthate showed that arsenopyrite was depressed by the addition of a moderate amount of Portland cement, but pyrite was not depressed by it. In the flotation tests of the artificial mixture samples with arsenopyrite and pyrite, following pH were adjusted to be 10.5 by Portland cement, different amount of amyl xanthate was added. The results from these studies showed that flotation recovery of pyrite was 100 per cent under the condition of some addition of amyl xanthate, but arsenopyrite was not floating at all. Portland cement shows remarkable depression of galena, but its effect on the flotability of chalcopyrite is not as clear. In the pulp under Portland cement addition, chalcopyrite can be easily activated by the addition of sodium bisulphite, whereas galena is depressed more effectively. From the batch flotation tests with the pyrite concentrate, the galena concentrate and the Cu-Pb bulk concentrate from the mines, it was confirmed that the results of the batch flotation tests agree with the results of the fundamental flotation tests. The effects of depression by Portland cement on pyrrhotite, marmatite and stibnite are also discussed briefly.

Jan 1, 1993

By E. M. Baroody

MUCH information on intermetallic diffusion has been obtained in experiments in which two volumes, initially at different uniform concentrations, are maintained in contact at an interface which is plane, or nearly so. Concentration-distance curves are obtained after suitable times, and analyzed on the basis of a one-dimensional form of Fick's law In early work the linear equation to which Eq. 1 reduces when D is independent of concentration was used. However, when the initial concentrations c, and c, are appreciably different this simplification is often unjustified, and the suggestion by Matanol in 1933 of a way of avoiding it was welcomed. Matano's paper was based on work done as early as 1882 by Boltzmann.2,3 In 1938 Rhines and Meh14 reported an extensive investigation of systems in which the diffusion coefficient depends strongly on concentration, and included a detailed description of the Matano-Boltz-mann method. To a large degree, this description represents the formal method as it is understood and applied today, most later discussions having emphasized thermodynamic and mechanistic aspects of diffusion. Exceptions are the comments of R. V. Churchill, contained in a paper by Ham, Parke and Herzig,5 and the papers by Hall8 and by Kirkaldy.7 More discussion appears necessary since some aspects of the problem remain obscure. Better computational procedures are also needed. The common method, involving graphical determination of slopes and areas, is inconvenient and makes the estimation of errors difficult. Background of the Matano-Boltzmann Method Eq. 1 is to be considered along with initial and boundary conditions. Take the origin of x at the

Jan 1, 1958

By L S. Barbour, M K. Meiers

Soil covers for mine waste are subject to changes in structure as a result of root development, and wet/dry or freeze/thaw cycling. The purpose of this study was to evaluate the changes in the hydraulic conductivity of three non-compacted clay covers over time. The covers are located on a sodic/saline overburden fill (30-Dump) at the Syncrude oilsands mine in Fort MacMurray, Alberta, Canada. Monitoring of these covers for temperature, matric suction, and water content by the University of Saskatchewan has been ongoing for more than three years. The three covers (D1, D2, and D3) were constructed in 1999 and are 50 cm, 35 cm, and 100 cm thick. The covers are comprised of a surface layer of reclaimed peat/mineral mix over a secondary reclaimed mineral soil (glacial till or glaciolacustrine clay), placed over a sloping shale surface. Field measurements of hydraulic conductivity within the secondary layer were obtained using a Guelph Permeameter during the 2000, 2001, and 2002 summer field seasons. Repeated measurements were made within the D1, D2, and D3 covers at depths of approximately 40 cm, 30 cm, and 60 cm, respectively. The values of hydraulic conductivity for the covers were similar to each other during each of the field study seasons. The mean hydraulic conductivity of the secondary layer increased every year: 2.5 + 10-6 cm/sec to 2.1 + 10-4 cm/sec to 4.3 + 10-4 cm/sec from 2000 to 2001 to 2002. Soil temperature data shows that one freeze/thaw cycle occurred each year at the measurement depths.

Jan 1, 2003

By Frank Foote, Willard L. Bruner, Eric R. Jette, Y. New york

The alloys of gold and iron were investigated in 1907 by Isaac and Tammann,l who determined the thermal diagram for the entire system by thermal analysis and microscopic examination. They also reviewed the previous literature. Since that time the present authors have been able to find only two additional references. Guertler and Schulze2 examined the electrical resistance of iron alloys containing up to 40 per cent by weight of gold between 0" and 200" C.; the alloys were in the form of wires. The main result of this work was to confirm the solid solubility limit found by Isaac and Tammann; namely, about 20 per cent Au. More recently, Shih3 has examined the magnetic properties of gold alloys containing up to 10 weight per cent iron and particularly the range below 5 per cent. The alloys in the lower range were found to be paramagnetic; the 10 per cent alloy was ferromagnetic. The present investigation was undertaken to determine the solid solubility limits at various temperatures, particularly below the a-y transformation point of iron, since these solubilities are of some importance in connection with the working of the alloys in the manufacture of certain "grey" and "blue" golds. Materials and Methods The gold was obtained from the U. S. Metals Refining Co. and contained 99.99+ per cent Au. The electrolytic iron had been annealed in hydrogen and contained impurities as follows: P, 0.035; Si, 0.001; S, C, Mn, Cu, each 0.01 per cent. Weighed quantities of the two metals were placed in small crucibles lined with pure sintered MgO; a saturated solution of magnesium nitrate

Jan 1, 1934

By Stein Wennberg, Snorre Tessem

INTRODUCTION The mine is situated in the middle of Norway 150 km north of the town Trondheim. The iron ore deposits were discovered in 1906 and have been continuously mined since. The first owner was A/S Nordiske Grubekompagni. In 1912 Fosdalens Bergverks-Aktieselskab was established; since World War II it has been a wholly state-owned company. The location is advantageous, with mining facilities, ore dressing plant and stockpile situated near the northern head of the Trondheimsf jord. The iron ore always occurs in Ordovician lavas and sediments, now altered to greenschists, keratophyres and limestone. The ore bearing zone is 150 km long. The deposits consist of two parallel linear ore bodies lying one above the other in the same stratigraphic horizon which dips 70' to the south. The upper body is 50-100 m high, the lower one 250 m high, while the distance between the two bodies in the East mine varies between 20 and 60 m. The ore width varies between 5 and 8 m. The ore bodies strike WSW and plunge between 10' and 15" in this direction. To date continuous ore has either been worked or opened up along a total strike length of 10 km. Until 1969 all ore was mined in the western part of the deposit called the Western mine. In the spring of 1969 production started in a new mine, the Eastern mine. The ore bodies in this new mine are geologically the same as in the old mine, but they have been displaced 700 m downwards along a major fault in the Fosdalen valley.

Jan 1, 1981

By H. J. Chalmers

"Since the advent of large volume flotation machines, Cominco Ltd. has actively studied possible application of such machines to their various milling operations. A number of installations have been made and more are on the drawing board. This paper gives a description of these units, information as to choice of equipment, and information as to operating experience. Mechanical and operating details of six installations are summarized. Three different types of machines are discussed.Pine PointThe original Pine Point zinc flotation circuit comprised conventional roughing with two stages of cleaning. Over the years with increase in feed tonnage there have developed two adverse conditions; namely, a reduction in zinc concentrate grade coupled with an increase in MgO in the concentrate. This resulted in higher freight payments along with more severe smelter penalties. An intensive test program, in 1971, showed that the concentrate grade could be raised by 1.5 units of zinc along with a reduction in MgO from 0.8% to 0.47.. Subsequently this was done by adding two additional stages of cleaning using 16 cells of Denver 200-V's. The project was completed in January 1973 at a cost of $510,000 to give an estimated annual savings of about $390,000.Selection of the Denver Model 200-V was based on minimum floor space requirement, availability, and favourable operational and maintenance experience with Denver 100’s. As it happens it was possible to ""shoe-horn"" the 16 cells into place with a minimum of plant alteration. Some problems have been encountered with a tendency to ""sand up"" at high pH, particularly at the corners. Otherwise operational service has been very good."

Jan 1, 1974

By Wallace E. Johnson, Leslie R. Hill

As part of a continuing study of intense energy effects on the earth, such as explosive cratering for Plowshare, large scale hydro- dynamic computer codes which numerically integrate the two-dimensional mass, momenta, and energy conservation equations have been adapted for use on geological materials. Experimentally determined nonlinear dynamic equations of state and constitutive equations governing material strength are incorporated into a two-material Eulerian code, DORF. With the use of this code, impact studies have been made of projectiles with arbitrary shapes in the r,z cylindrical plane normally incident on semi-infinite half-space targets. The impact of projectiles on rocks has been studied empirically and experimentally; however, this paper employs a theoretical approach. Particular examples selected involve the impact of aluminum and iron projectiles on oil shale at velocities of 0.5 and 1.0 cm/µsec. These studies offer a quick and economic means to edit quantities unavailable in an experiment and to independently study the effect of varying parameters such as material shape, density, and strength, and impact velocity. Results reveal early time agreement with experimental high-speed photography as seen in the bowl-shaped crater and spray. Initial impact pressures at the projectile-target contact are in close accord with the one-dimensional Rankine-Hugoniot relations for the impact of dissimilar materials. These equations require local continuity of pressure and particle velocity across the interface and were found to hold locally, quite independent of projectile shape. Essentially all projectile energy is transferred quickly to the oil shale target (tens of microseconds). Over 75% of the original kinetic energy

Jan 1, 1971

By F. T. Lee

Directional dependence of strength and deformation properties of the Mount Waldo granite pluton in southeastern Maine is controlled by joints and microfractures whose orientations are linked to flow- induced alignment of microcline crystals. Longitudinal and cross joints which formed during cooling of the mass, as well as much younger sheeting fractures, are commonly associated with subparallel, discontinuous microfractures. The orthogonality of microfractures (open, closed; filled, unfilled; bubble planes) establishes the ease of splitting of the granite. The easiest splitting direction (rift) is subhorizontal, the second easiest direction (grain) is parallel to the cross joints, while the direction of least easy splitting (hardway) is parallel to the longitudinal joints. Static and dynamic measurements made in the field and laboratory established that structural features are responsible for the marked stiffness anisotropy of the granite. In the central part of the pluton the static Young's modulus in the north-south direction averages 31.1 GPa, and 20.9 GPa in the east-west direction; the stiffer direction being parallel to the long C-axes of microcline phenocrysts and microfractures as identified in outcrop, core samples, and thin sections. Vertical downhole sonic measurements of dynamic moduli ranging from 2.5 to 16.2 GPa appeared to be anomalously low when compared to the static horizontal values. However, the field sonic values were confirmed by laboratory sonic pulse testing of oriented cores. The field results reflected closely spaced layers of open horizontal microfractures. Those deformation and strength properties that are closely tied to bubble planes, filled microfractures, and microcline orientation could be extrapolated to greater depths with good hope of success.

Jan 1, 1984