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By L. Adler

Two basic cases involved in the design of an opening in bedded rock are: 1) where the beds deflect from each other so as to be separated; and 2) where the beds deflect onto their lower neighbor, loading the latter while reducing their own load. Analysis of case 1 is relatively simple, while the interference of the original deflection curves in case 2 complicates analysis of the latter. Figures and formulae are presented for determination of interference loading in this situation. The design of an opening in bedded rock involves two basic alternatives.1'2 In one case the beds deflect away from each other, so as to be separated from their neighbors; in the other case the beds deflect onto their lower neighbor, loading it, while reducing their own load. This is shown in Fig. 1. The first case lends itself to a simple analysis, since the upper and lower boundaries of each beam remain a free surface. In the latter case, however, due to the interference of original deflection curves, the analysis is more complex. Earlier investigators of this interference problem solved it by making the tacit assumption that this type of loading was uniformly distributed along the beam's length. While there is no intuitive justification for this assumption, its use does lead to an approximate solution. Still, a more exact solution does not require this apparently unrealistic restriction. To achieve initial simplicity, the analysis will at first be limited to a two-bedded sequence, as in Fig. 2. Since both beams have identical end conditions and spans, the original deflections of their center lines are members of the same family of curves, as shown in Fig. 3. Therefore, if interference occurs at one point along their center lines, it will occur at every point. For convenience, the midspan point is that usually examined. Deflection at midspan for a uniformly loaded beam regardless of end conditions is: where c is a constant depending on end conditions; w is the body load and equals yh, lb per ft; y is the specific weight of rock, lb per ft'; L is the span, ft; E is Young's Modulus, lb per ft2; I is moment of inertia (for a rectangular section), I = bh3/12 = h3/12, (ft4); b is the width of beam and equals one; and h is the thickness of beam, ft; or 3U > yB an Substituting the appropriate values into Eq. lb, interference between the two beds can be predicted. Should it occur, the additional loads along the lower boundary of the upper bed and the upper boundary of the lower bed must be determined. From the principle of action and reaction, these added loads are known to be equal and opposite, as indicated in Fig. 4. Since the final deflection curves for both beds are identical (Fig. 3), their successive derivatives of y with respect tox must also be identical. That is:

Jan 1, 1961

By H. Jehn

Like some other Pt-group metals palladium shows a low but considerable solid solubility of oxygen, which was found already from oxidation studies. The oxygen solid solubility of palladium in equilibrium with gaseous oxygen has been investigated at 900 - 1300 °C in oxygen (665 mbar) and air by gassing and analyzing polycrystalline samples. The 0-concentrations range from 40 to 90 ppm and decrease with rising temperature. The isobaric solubility can be represented by the least-squares fit log c0 = 0.5 log p02- 0.32 + 920/T (c0 in wt. ppm, p02 in mbar, T in K). The thermodynamic data of the exothermic solution reaction are calculated to ?H°= -17.6 kJ?mol-1 and ?S° -76.5 J?mol ? K-1. The behaviour of palladium in an oxygen atmosphere is characterized by the simultaneous reactions of the solution of oxygen in the metal and the formation and evaporation of volatile oxides besides the pure metal evaporation.

Jan 1, 1984

By M. M. Singh, J. W. Brown

Three rocks of highly varied physical properties are selected for the first reported experimental study concerning microseismic activity of rock under tension to determine the effects of static fatigue, loading rate, repeated loading and rock anistropy compared to compression and bending loads. The microseismic method of detecting rock under deformation may be a great potential tool in surveillance and location in situ of dangerously stressed strata, as well as predicting rock failures. Noises emitted under load or the rate of energy (energy of noise pulses generated per unit time) are computed for varying conditions. The tests are conducted at constant load on a dead weight loading machine to eliminate all possible extraneous noises — an indispensable precaution — at various load levels. Experimental results are reported including the relation of total energy emitted to tensile strength of rock and the possibility of simulating a phenomenological model for microseismic activity. Plots of some of the experiments are included. INTRODUCTION Rock failure, whether on a large scale faulting in the earth's crust and rock bursts in mines, or on small scale ruptures of laboratory test specimens, generates transient vibrations in the rock mass. Mechanisms of intermittent deformation, such as twinning and cracking through and between mineral grains, also produce similar vibrations, but of very small amplitude. Such vibrations from both deformation and failure are referred to as microseismic activity, rock noise, or occasionally seismo-acoustical activity. An individual rock noise is sometimes

Jan 1, 1967

By Euzebio De Oliveira

ONE of a recent batch of samples from the Serra da Baliza, in the state of Parana, Brazil, contained asphalt and a dark heavy oil; and workmen on the railway from Porto União to Uruguay discovered asphalt, coming from eruptives that outcrop along the Rio de Peixe. The occurrence f asphalt in the triassic eruptives of southern Brazil, however, has been known a long time, according to Dr. Gonzaga de Campos. It is generally believed that the Botacatú sandstone is always a hard vitrified rock, from the metamorphic action f. the overflowing eruptive contacts. In this region, however, the contact metamorphism is almost nil; the sandstone is slightly hardened in a narrow zone about 20 to 30 cm. wide. In many places, the sandstone is so friable as to be easily reduced to sand, which is used-.in, mortar for building in Guara-puava and Palmas. South and west from Porto União,. this bench of sandstone is about. 50 m. thick, and is capped by a heavy bed. f basic eruptives, many of which are amygdaloids. Dr. Geo: P. Merrill, after studying the triassic eruptives collected by the Coal Commission, reached the conclusion that. "All these rocks are of typical basalt-diabases, not in any essential different other than in structure. An interesting mineralogical phase is its paucity in olivine, which in many cases is completely lacking. Professor Hussak, who carefully studied these rocks and their accessory minerals, decided that in the dikes they are granular (diabase) and, that in the lava sheets, porphyritic (augite-porphyrite or melaphyre), and that the latter pass evidently to normal diabases and are always typical of effusive rocks. The examination f many slides from dikes and sheets leads us to adopt the opinion of Professor Hussak; the rocks of the dikes are of ophitic structure, while that of the sheets show a great variety f structure and may vary from almost granular to basaltic. The great paucity in olivine had been noted by Hussak, who classes as melaphyres, the porphyritic triassic rocks in Brazil which contain olivine.

Jan 4, 1921

By Charles W. Merrill

Obsolescence in the mineral world is virtually nonexistent if the term is taken to mean that a mineral commodity, once established in commerce and industry, subsequently has fallen into disuse. We are living in an age of minerals. Each generation puts an increasing array of mineral-based commodities, in larger quantities, to more uses than ever before. Bastnasite, a museum mineral and a collector's item a few years ago, is now produced in quantity at Mountain Pass, Calif. Uranium, a minor byproduct of vanadium mining in the Rocky Mountain plateau area before World War 11, has grown to be a leading mineral product in several western States. And finally the total quantity and value of minerals both in the United States and in the World establish new records almost yearly. Surely the mineral industry as a whole is not obsolescent in our economy. Nevertheless, there are particular uses for particular minerals that are obsolescent and some applications have been supplanted entirely. Tin does not occupy the prominent place in foil manufacture that it once did, and the schoolboy's slate left most classrooms before the oldest of us were born.

Jan 9, 1964

By J. B. Dilworth

OUTCROPS of coal have bees discovered is many localities is the Philippine archipelago, and practically all of the larger islands contain deposits of this mineral. Very little prospecting has been done to determine the value of the various coal-bearing areas, but so far as known, the largest and most promising fields are found : (1) is northern Cebu; (2) is the small island of Batan, a part of the province of Albay is southeasten Luzon; (3) is the somewhat larger island of Polillo, off the east coast of Luzon, and (4) is southern Mindoro, sear the small coast tows of Bulalacao. Northern Panay, south-central Cebu, and various localities is southern Luzon, Masbate, Negros, and Mindanao also afford evidences of the existence of coal-beds, the extent and value of which have not yet bees proved. The general position of these islands and districts is shows on the map of a portion of the Philippine Islands, Fig. 1. Some of these coal-fields have been known for many years (coal was discovered is Cebu 1827 and is Batas is 1842),1 and several futile attempts were made by the Spaniards to operate mines is these districts. But owing to many circumstances, chief among which were indifferent management, the political unrest of the islands, natural difficulties of transportation, and those inherent in the mining of steeply-inclined and somewhat irregular seams, no considerable output was ever obtained from any of these mines, and the fuel required is the many departments of industrial and political life has continued to be drawn largely from Australia and Japan. These conditions exist to a great degree at present, and though much interest is the coal-deposits of the Philippines

Jan 1, 1909

Jan 1, 1967

By AIME AIME

ARRANGEMENTS for the Annual Meeting of the Institute were well advanced at the end of December as the following program will show. Heretofore this has been printed separately, but its inclusion in the Annual Review issue of MINING AND METALLURGY will, it is hoped, make it more easily available for reference until the final program is issued, which will be distributed at the meeting. Added details will appear in the February issue. Last year's meeting drew a record crowd of over 2300 which should be exceeded this year. Early reservations at the headquarters hotel, the Waldorf-Astoria, or any other convenient hotel are desirable, as are prompt reservations for the Annual Dinner. No one need worry about too much speechmaking this year, for the honors will be awarded and accepted in a few words instead of a few paragraphs, in seconds rather than minutes.

Jan 1, 1939

By J. W. MacDonald

Review of equipment, performance, and shaft design plans including head-frames for sinking and forms for lining are given. Also included are comparative data for shafts of 11 x20 ft and 193/4 x 30 ft with 756 and 666-ft depths, respectively. Advantage from curtain wall installation with "slip forms" which warrant consideration for normal lining are outlined. A preliminary review is also made of "chemical grouting" to stop water inflow leakage with Halliburton equipment and service. Two coal mine shafts recently completed in Franklin County, Ill., afford experience and accomplishment to warrant review. These shafts provide access to a tract with a potential recovery of one hundred million tons. This work provided the initial sinking by other than a contractor's organization since 1918. Four additional shafts required during the interim were sunk under contract arrangement with others. Supervisory contact and inspection afforded experience to govern planning and conduct of the recent work. TEST DRILLING Core test holes were drilled within each of the two shaft locations. Four additional cable tool holes were drilled on a radius of 700 ft from the shaft bottom to determine the coal seam elevations and govern the underground layout plans for each shaft. A graphic log of the hoist shaft test drillhole is shown by Fig. 1. A very soft sandstone was found at a depth of 16 ft. Cored recovery of the sandstone proved much weaker than the overlying compacted sand secured with coring facilities for soil recovery. Gradation from the very soft sandstone to fairly hard material occurred with the next 14 ft, extending to a depth of 30 ft. The weak character within the upper portion entailed need of adequate protection when sinking as described later. A part of the sandstone provided sufficient porosity and permeability to warrant further investigation. Adjacent cable tool drilling for temporary water supply disclosed inflow was limited to 2 gpm with a depth of 40 ft. It was increased to 12 gpm during the next 50 ft of drilling and occasioned subsequent precaution when sinking. General arrangement of facilities for sinking the hoist shaft is shown by Fig. 2. An available steel frame building was used to accommodate the hoist, compressor, shop, and shower or change room. The stiff leg derrick with 90-ft length of boom permitted removal of forms from the wood shop to the storage area or delivery within the shaft. Reinforcing steel and other needs were similarly handled, in addition to headframe erection. The headframe was placed over one end of the shaft to enable passage of forms for lining through the adjacent half next to the stiff leg derrick. The steel headframe as shown by Fig. 3 was fabricated locally. Side anchored cables from the

Jan 1, 1961

By Howard R. Pratt, Jimmie L. Bratton

The Air Force Weapons Laboratory (AFWL) has been carrying out a series of experiments whose principal purpose is to measure the dynamic response of rock media to large pressure pulses. Coupled with the field experiments have been theoretical calculations simulating this response. These two approaches allow an appraisal of the current ability to measure in-situ rock response under extreme conditions and also give a fair estimate of the current state-of-the-art in the area of computer calculation of the response of "real" geologic media to a large load. The area chosen for the test series is composed of a sequence of sedimentary units (shale, sandstone, and limestone) located in the Estancia Valley 45 miles east of Albuquerque, N.M. (Fig. 1). The units, which dip gently off the uplifted Manzano Mountains to the west, are essentially horizontal at the test site. An extensive geologic and geophysical investigation of the area was carried out in the form of surface mapping and seismic exploration. Numerous holes were cored and material properties were determined from tests of the cores. In-situ geophysical measure¬ments were also carried out. The experiment consisted of loading a 60X40 ft test area with a 4000-psi transient exponentially decaying pressure pulse. The pulse was initiated at one end and traveled the 60-ft length of the test bed. The test area was instrumented with acceleration, velocity, and strain measuring devices placed in drill holes to depths of 30 ft. Theoretical computer calculations of the response of the layered geologic media have been carried out on the AFWL CDC 6600 using one and

Jan 1, 1972

By E. H. Timmerman, A. F. van Everdingen, J. J. McMahon

The prevent paper contains a method which combines the material balance equation' with the water influx equation' to obtain reliable values for the active oil originally in place and a quantitative evaluation of the cumulative water influx. The method is illustrated by an application to a reservoir without original gas cap. In the absence of an original gas cap. results may be obtained using only field production and pressure data, PVT analyses. and a minimum of subsurface information. CHARACTERISTICS OF RESERVOIR AND RESERVOIR FLUIDS Production in the field under review is obtained from the top of the Wilcox formation of Eocene age, at a depth of approximately 8,100 ft subsea. The structural map, Fig. 1, shows that the accumulation, half elliptical in shape with the long axis in east-west direction, is trapped to the north and on the upthrown side of a normal fault. A number of east-west faults with additional minor faulting in random directions are found in the general area, and seismic information and production performance indicate in this particular case the existence of a second fault a short distance downdip, with a strike more or less parallel to the fault controlling the accumulation. It is estimated that 1,830 acres were originally underlain by oil and that the maximum thickness of the original oil column, about 37 ft, was only slightly greater than the maximum thickness of the oil-bearing sand. Maximum net sand thickness was estimated at approximately 26 ft. From logging and subsurface information the gross sand volume has been placed at 37.400 acre-ft. which reduces to about 27,500 acre-ft after probable non-productive intervals have been deducted. The following table presents laboratory analyse; data for the Wilcox sand cores. Average Average Samples Considered Permeability Porosity All Samples 236 md ..19.9percent Samples with k>l md 256 md 20.5 per cent Samples with k>8 md 275 md 20.9 per cent Interstitial water was estimated at 15 per cent. The initial gas-oil ratio was approximately 900 cu ft/bbl. and the initial shrinkage factor was determined by the laboratory to

Jan 1, 1953

Discussion of the paper of Frederick Laist, presented at the Butte meeting, August, 1913, and printed in Bulletin No. 79, July, 1913, pp. 1147 to 1162. J. C. DICK, Salt Lake City, Utah :-I would like to ask Mr. Laist why a 10 per cent. salt solution was used. MR. LAIST :-The reason for using salt in the solution is to get .the sulphur. The solution of dilute sulphuric acid has no solvent action on the sulphur even after roasting, and the addition of the salt is made primarily to dissolve the sulphur chlorides. MR. DICK:-I would like to ask also if you made any experiments as to grinding fine your calcines, rather than leaving the coarse material. MR. LAIST :-We have not made any experiments along those lines except in the laboratory, but the objections which we have to grinding are that the difficulties of roasting are very much greater when roasting finely ground material than when roasting coarse material, and the difficulties of leaching are somewhat increased; the percolating system is simpler and easier to manipulate, particularly when acid solutions are used, so that we prefer from our experience not to grind. STUART CROASDALE,* Denver, Colo. (communication to -the Secretary +) :-In order to meet the conditions involved in his ore-treatment problem, Mr. Laist has developed a very interesting and apparently successful metallurgical hybrid which he calls the oxychloridizing roast. The lower floors of the MacDougall furnaces are made to accomplish what used to be done on the " cooling floor" in the old days of salt roasting and " hypo " or brine leaching of silver ores.

Jan 11, 1913

By B. C. Blake

IN general, billet-type or long slender ingots are used when it is desired to produce directly from the ingot in one conversion a product of medium or small cross-sectional area. They are designed to eliminate the blooming and billet-mill stages of the usual procedure. As used at Connors, they constitute a means of keeping a continuous rolling mill busy in the production of high-quality small rods, small angles, hoop stock, baling ties and concrete reinforcing rods without the need for a blooming or billet mill. They represent sound steel with the best surface that is commercially practical to use in the rolling of small continuous mill products.

Jan 1, 1947

THE first session was held in the small hall of the Academy of Music, on Tuesday evening, February 18th, 1879. The proceedings were opened by the reading, by President Eckley B. Coxe, of the following Address : SECONDARY TECHNICAL EDUCATION. Technical education is a subject to which both the American Institute of Mining Engineers and the American Society of Civil Engineers have of late years given much attention, and deservedly so. We all remember the admirable address of our former President, Mr. Holley, at the Washington meeting, upon this subject, and the very interesting reunion of the two societies in Philadelphia for its discussion. The problem to the solution of which the meeting devoted its attention was, "Shall the practical education of the engineer in the mine, in the rolling-mill, in the workshop, or in the field, precede, be contemporaneous with, or follow his theoretical studies in the technical school ?" I do not propose to add anything to what was so admirably said by so many of our leading engineers on that occasion ; but I shall ask your attention to another question in technical education, which seems to me equally worthy of our consideration, and which, I am sorry to say, has as yet attracted but little attention in this country. It is, "Shall the apprentices (I call them so for the want of a better general name), who are growing up and learning their trades in and around our mines and works, and from whose ranks the master mechanics and foremen of the future must be taken-shall they be provided with some means of obtaining as much theoretical training as may be necessary to enable them properly to understand the various processes and operations that they may be called upon to superintend, and not be obliged to pick up, as best they may, here a little and there a little truth mingled with much error?" In the former case, those who have the ability and industry to avail themselves of the advantages that should be offered to them would fit themselves to become real foremen, men who would understand and appreciate the true engineer and his methods. Of late years the young men of this country who have wished to enter our profession have had great facilities offered to them for so doing ; there have been undoubtedly great improvements in the methods of instruction; and although I am very far from imagining that no further progress can be made, or is demanded, yet I feel sure that

Jan 1, 1879

Jan 1, 1879

By G. R. St. Pierre, A. J. Wilhelem

In connection with the reduction of hematite or magnetite to metallic iron, it appeared desirable to study the rate of reduction of each oxide to the next lower oxide under conditions which excluded all other condensed phases. For this purpose, pellets of Fe,O,, Fe,O,, and oFeOo were prepared. A gas train for the preparation of Ar-Hz-H20 mixtures was employed to establish a continuous flow of a controlled atmosphere over a pellet suspended on a balance. In this manner the following individual reduction steps could be studied: For example, pellets of hematite were reduced solely to magnetite by adjusting the gas atmosphere such that it was oxidizing to wustite. In other words, the reaction was complete when the hematite pellet had been totally converted to magnetite. The pellets were prepared from Baker Chemical ferric oxide. The ferric oxide powder was moistened and handrolled. Air sintering at 950°C produced Fe,0, pellets with a density of 3.65 g per cm3. The pellets ranged in size from 0.6 to 1.2 cm diam. The magnetite and

Jan 1, 1962

By Ta M. Li

How will phosphate producers in southeastern Idaho fare with growing governmental regulations and environmentalism of the late 1970's? With a similarity that is reminiscent of the battles between the coal industry and environmental-conservation groups earlier in the decade, Idaho's future growth and a nation's need for phosphate fertilizer products remain uncertain. The catalyst that brought the issue to the forefront was the preparation of an Environmental Impact Statement (EIS) addressing the development of phosphate resources in southeastern Idaho. Although the final EIS was published in August 1977, resolution of rational and orderly growth in this potentially vital region remains stifled as Secretary of the Interior Cecil Andrus virtually "sits" on it.

Jan 1, 1978

By H. F. Silliman, Daniel R. Hull, Earl W. Palmer

THE brass-rolling industry has not had a great deal of experience with antimony in its product. There have been some recent excursions with antimony as a corrosion inhibitor in tubes, but in sheet brass it has been regarded with apprehension and generally avoided. This is not to say that [ ] contaminations have never occurred, and probably a great many brass mill men have had their own ideas on the effect of such contamination. Our own views were based upon certain experiences some years ago with strip castings that split lengthwise in the early stages of rolling. The nature of this splitting is shown in Fig. I, from a photograph taken in 1922 as a record of 20 bars of 65-35 common brass made with an antimonial brand of copper. These bars were cast 6 ¾ in. wide by 1 in. thick by 45 in. long. In the first pass through the rolls, 19 of the 20 split lengthwise throughout their length, while each half curved outward in a wide arc as it emerged from the rolls. [ ] In those days, if splitting was not a frequent occurrence, it was not unfamiliar. One can recall periods of short duration when large amounts of common brass would behave in this way. There was nothing imaginary about these spells. The affected metal would split lengthwise in the breaking rolls, and no maneuvering of mill practice made any difference. The condition would descend like a plague, demoralize the mill for several days, and disappear. It is doubtful if anyone knew the cause-however many explanations may have been current. In 1921 a quantity of split brass was traced to the use of fired small-arms

Jan 1, 1943

By R. F. Hinds

A pressurizing system was designed and built to apply a radial pressure of 5.000 psi to rock samples. Samples of the Bradford, Weir and Kirkwood sandstones were subjected to radial pressures parallel and perpendicular to the bedding in the system and the changes in conductivity, porosity and permeability were deter-mined. Asymptotic decreases in conductivity, porosity and Klinkenberg permeability were observed over the 0- to 3,500-psi range. From these data, the increase of formation factor over the same range was calculated. The cementation exponent expressed in the Archie equation was found to increase with pressu,re. The rate of change varied from formation to formation. Only small differences were observed for samples taken parallel to the bedding as comnared to those taken perpendicular to it except for the Bradford sand. Above 3,500 psi the data are not good enough to tell if the properties continue to fall-off asymptotically or in a different manner. A possible explanation for the probable litnit of the asymptotic rate around 3,500 to 4,500 psi is that this represents the maximum pressure which the formations have unrdergone during their geological life as a result of burial. INTRODUCTION For many years measurements have been made in the laboratory of the properties of oil-bearing sandstones with little consideration being given to whether these properties had been changed when the samples were moved from their original position in the ground to the laboratory. Relatively little has been reported in the literature on the effect of pressure on the properties of sandstones. The changes in permeability for eight typical consolidated oil-bearing sandstone samples with overburden pressure (0- to 15,000-psi range) was presented by Fatt and Davis' in graphical form. In 1953 Fatt' also reported the relationship between porosity and overburden pressure for four typical consolidated oil-bearing sandstone samples (0- to 5,000-psi range). Fatt later described the changes of formation factor and porosity of 20 typical oil-bearing sandstone samples with overburden pressure changes (0- to 5,000-psi range) giving the values of the coefficients and exponents in the Archie' equation, and the more general Winsauer equation', where C, k and m are empirical constants, F is the formation factor, and + is the porosity. During the experiments of this investigation the core was contained in a neoprene rubber sleeve as shown in Fig. 1. It was held between two steel end members which were mounted in a steel cylinder. The unassembled pressure cylinder with its component parts is shown in Fig. 2. The core was insulated from the two steel end members by a Teflon sleeve with a small hole in the

By H. W. Fleming, R. R. Brooks

The Clearwater Deposit, a small occurrence of massive-sulphide mineralization enclosed in an envelope of disseminated-sulphide mineralization, was discovered as a result of an aeroelectromagnetic survey in New Brunswick in 1955. Subsequently, additional flights were made over the deposit and various ground follow-up methods were employed to ascertain the nature of their response. All methods proved to be capable of indicating the occurrence with varying degrees of precision. This paper is a presentation and a discussion of the magnetic and electromagnetic data, both airborne and ground, and the self-potential data obtained over this deposit. The attention of Canadian mining exploration companies was initially focussed on New Brunswick by the discovery, in 1953, of the Brunswick ore body. Ground electromagnetic surveys were of considerable assistance in locating and developing this deposit. In the following year, 1954, the Heath Steele base-metal deposits were discovered by employing an airborne electromagnetic device and ground electromagnetic surveys to follow-up the airborne indications. These discoveries demonstrated clearly that both airborne and ground electromagnetic techniques were applicable for locating the near-surface deposits of massive sulphides present in this region. Airborne electromagnetic equipment became available on a contract basis through Aeromagnetic Surveys Limited early in 1955 and was used extensively thereafter throughout a large portion of northern New Brunswick. It was as a result of one of these surveys with Aeromagnetic Surveys Limited equipment in the summer of 1955 that the Clearwater Deposit was detected. The airborne anomaly was located on the ground by means of an electromagnetic survey using a Swedish Slingram unit. During 1956, the region was investigated more thoroughly- in the hope that other sulphide bodies might be located. Airborne electromagnetic coverage was extended and the Clearwater Deposit itself was used as a testing ground for the various methods and types of equipment currently in use in New Brunswick. In this paper com prative data are presented for the airborne magnetic, airborne electromagnetic, ground magnetic and ground electromagnetic surveys over this deposit. The ground electromagnetic instruments used were the McPhar vertical-loop unit and the Slingram and Boliden horizontal-loop units. Self-potential surveys were carried out with a McPhar unit. From the geophysical point of view, all ground electrical methods employed indicated the presence and the extent of the massive-sulphide mineralization with a good degree of accuracy. The horizontal-loop methods however, defined the contacts more precisely as is to be expected when dealing with a flatly-dipping

Jan 1, 1961