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By George C. Lipsey

FOR many years the mining of coal and other minerals occurring in sedimentary formation has been planned according to information obtained by diamond drilling. Placer mines have used churn drills for sampling and estimating deposits, and some metal mines have used the method either wholly or in part. The diamond drill method, therefore, although not entirely new, has come into more prominence in the last few years. Several large-scale developments now being planned or in the production stage have used this method in varying degree. This paper will describe the operations of the Howe Sound Exploration Co., Ltd. at Snow Lake, Manitoba, where a gold mine was developed and equipped for mining and milling wholly on the basis of diamond drilling results. The property has been in operation nearly 3 years, so that results can be compared with the estimates and assumptions made from the diamond drilling. In developing the subject it is necessary to outline as briefly as possible the normal method of mining, from discovery to production stage. Table I sets forth these various stages, the methods of financing, the percentage of total cost, and the relative time interval required for each section of the work. The plan presented in this table cannot be applied to all mining developments, but it gives a basis on which to work. In Stages 2 and 3 the investment is moderate, and if the property does not respond favorably the options or interests can be terminated. Stage 4 represents a sizeable investment, and it is more difficult to drop the property after this part of the operation is completed. Stages 2, 3, and 4 may be repeated several times by diflerent groups or companies before Stage 5 is reached, but when Stage 5 has been started the total capital investment must be provided and there can be no turning back. It will be noted that there is a total of 116 units of investment in the overall cost if one company proceeds with Stages 2, 3, 4, and 5 in order. Stage 4, however, consumes time which is important when markets are being considered. Bringing a property into production when metal prices are low is much more difficult than when the prices are high, and if this stage can be set aside production is attained more quickly. When Stage 4 is eliminated the total becomes 86 units of cost for Stages 2, 3, and 5, but an adjustment of 14 units must be added to Stage 5. These 14 units represent the useable value of Stage 4. Thus Stage 4 represents an investment of 30 units if carried on before Stage 5, but 14 units if included with Stage 5. This is accounted for by the fact that development work can be accomplished more cheaply under Stage 5, since everything that is done is planned on a production basis with permanent services. Stage 4 must of necessity be governed by expenditures, and a great many temporary services, including housing and power plants, must be provided. The prospect shaft is a small one, and drifts,

Jan 1, 1953

By David J. Selleck, Eugene P. Pfleider

9.61. Introduction. Open pit mining methods produce more than 80% of all raw materials today in the United States. Much of this comes either from properties that formerly employed underground methods and were converted to open pit or from mines that ultimately must go underground when the economic stripping limit is reached. Generally the ores are transported over large vertical distances and techniques have been developed to do this economically. One approach is to combine conventional surface trucking, over relatively level roads, with the use of gravity and underground facilities. There are various modifications, depending upon the character of the orebody and the topography. Several schemes, as used in Sweden, Canada, and the United States, merit describing. One of the critical problems involved in the transference of ores from surface to underground is that of flow of bulk solids. Must it be crushed? Will it hang up in the transfer? What size and inclination of ore pass are required. How is the ore best fed onto the transporting device underground? As an example, the planning engineers for the Carol Project of the Iron Ore Company of Canada faced these problems in making their designs for the production and transportation of some 55,000 tpd from their Smallwood Mine in Labrador. Other operations, facing somewhat similar conditions, used other approaches of interest. This chapter describes some of the factors involved in the design, construction, and operation of a combination surface underground transportation system as applied to open pit mining operations. 9.62. Tunnel-Ore Pass Systems. The type, shape, dip, and size of the orebody, as well as the surface topographic features, generally estab-

Jan 1, 1968

CONTENTS PAGE ANDERSON, ARVID E., and CAMERON, FRANK K.-Recovery of Copper by Leaching, Ohio Copper Co. of Utah. Discussed by Thomas B. Brighton, H. C. Goodrich, Arvid E. Anderson, Thos. P. Billings, Frank K. Cameron 2 BEESON, J. J.-Mining Districts and Their Relation to Structural Geology. Discussed by Charles Keyes, Chas. A. Porter 4 DOBBEL, CHAS. A.-Deep-hole Prospecting at the Chief Consolidated Mines. Discussed by G. W. Crane 10 CRANE, G. W.-Notes on the Geology of East Tintic. Discussed by G. W. Crane, H. E. Havernor, N. O. Lawton 11 SACKETT, B. L., BARDWELL, CARLOS, JACOBSON, SIMON, and JENSEN, N. H. Lead Smelting in Utah. Discussed by D. W. Jessup, B. L. Sackett, E. H. Laws 13 BARDWELL, E. S., and MILLER, Roy H.-Pulverized Coal as Fuel for Copper Refining Furnaces. Discussed by L. D. Anderson, E. S. Bardwell, C. P. Crawford 15 WIGTON, G. H.-The Chief Consolidated Volatilization Process and Mill. Discussed by Thomas Varley, S. G. Olmstead, V. O. Lawton, O. C. Ralston.... 16 JESSUP, D. W.-Evolution in the Preparation of Ores for Lead Blast Furnaces. Discussed by W. Spencer Reid, D. W. Jessup, Carlos Bardwell 19 ALLEN, H. P., and MADGE, WM. C.-Chloridizing Mill of the Standard Reduction Co. Discussed by Thomas Varley, H. R. Hanley, H. P. Allen, George H. Dern 20 TUCKER, E. L., and HEAD, R. E.-Effect of Cyanogen Compounds on Floatability of Pure Sulfide Minerals. Discussed by Blarney Stevens 24 Mix, B. E., and BARKER, L. M.-Method of Unloading Ores and Coarse-crushing Practice at Magna Plant of Utah Copper Co. Discussed by W. C. Madge,B. E. Mix 25 KEIGLEY, C. T.-The New Byproduct Coke Plant of the Columbia Steel Corporation. Discussed by W. M. Grant, C. T. Keigley, A. C. Feilder 25 JACKSON, P. W.-Blast Furnace Plant of the Columbia Steel Corporation. Discussed by W. R. Phibbs, H. M. Henton 26 OLDRIGHT, G. L., KEYES, H. E., and WARTMAN, F. S.-Production of Ferric Sulfate and Sulfuric Acid from Roaster Gas. Discussed by G. D. Van Arsdale William E. Greenawalt, G. L. Oldright 27 MAZANY, M. S.-Braden Copper Company Caletones Smelter. Discussed by A. B. Young, G. L. Oldright 36 HARRINGTON, D.-Safety Methods in Utah Coal Mines. Discussed by Edward K. Judd, Otto Herres, Benedict Shubart, A. C. Watts, D. Harrington 36

Jan 12, 1925

By Donald L. Everhart

SOONER or later intelligent exploration for uranium leads to these questions: Where did the metallic ions that formed the orebodies come from? What processes and geologic factors were involved in ore replacement? These matters, of course, make a big difference in how best to look for orebodies. Before these questions are discussed it might be well to point out other factors bearing on the subject. The whole business of uranium exploration is only a little over ten years old, participation by the public is only about six years old, and real interest and activity by more than a few large mining companies has arisen only in the past two or three years. Throughout this short period, uranium exploration has been affected by the unique influences of necessary security measures and by division of the over- all job into individual projects by a large number of specialists in diverse fields. This has meant that a normal interchange of information on the nature of uranium deposits has really only just begun. Com- pared to the vast amount of published studies on iron, copper, lead, zinc, and gold deposits over the past 50 to 75 years, current knowledge of uranium deposits is in its infancy and much of the pertinent information is still scattered about in a number of unpublished sources. The volume of reports on all phases of uranium exploration is now beginning to mount at a remarkable rate, and geologists with widely varying specialized backgrounds in uranium geology are engaging in spirited debates over the origin of uranium and the relative importance of geologic controls of various deposits.

Jan 9, 1954

By Neville J. Price

In order that the reader may not be misled, I feel it necessary to comment upon the title of this paper. "Laws of Rock Behavior," one may take as being part of the all-embracing "Law of Nature" and this, according to the Oxford Dictionary, relates to the principles of conduct recognized as being pleasing to God. I feel it would be presumptuous to erect a code of rock behavior on this basis, so turn to a secondary definition, namely that a "Law" is that which is intrinsically reasonable. It is extremely unlikely that any group of geologists, or workers in rock mechanics would be in complete agreement about what could be taken to be "intrinsically reasonable." Therefore, this paper does not present any deified utterances, but rather deals with a few aspects of rock behavior which I consider to be intrinsically reasonable and with which I hope the reader will concur. The mode of behavior of rocks in the Earth's crust covers the range from wholly brittle to completely ductile ; with a deformation time scale which may be measured in milliseconds, for some events such as meteoritic impact, or in millions of years for the tectonic deformation involved in mountain building. A complete survey is, of course, outside the scope of an introductory paper, so I must be both brief and selective in my treatment. Any attempt to establish the mode of rock behavior in the Earth's crust should take into account data and relationships established in laboratory experiments and correlate these with field evidence. Consequently, the first section of this paper presents a brief discussion of the experimental aspects of rock mechanics which are pertinent to the subsequent discussion.

Jan 1, 1970

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

By Walter Nummela

INTRODUCTION By the end of 1979 pellet productive capacity from the processing of low grade iron ores in the Lake Superior-District will total 86 million tons per year. Of that tonnage, 72 million result from the processing of magnetic ores such as taconite, about 6 million tons from the flotation processing of relatively coarse grained specular hematite, and 8 million tons from the processing of fine grained non- magnetic ores at Tilden. The Tilden flowsheet represents a break- through in the processing of this type of crude ore and hence is unique in the Lake Superior District (1). Operations at Tilden started in late 1974 with Algoma Steel, J&L Steel Corp., The Cleve- land-Cliffs Iron Company, The Steel Company of Canada, Ltd., Wheeling- Pittsburgh Steel Corp., and Sharon Steel Corp. as participants. Cleveland-Cliffs operates and manages the operation. Other companies have conducted extensive pilot plant tests or are in commercial production in the processing of fine grained non-magnetic ore materials (2). Flowsheets and reagent schedules may be different for each particular application, but some of the problem areas in the processing of Tilden ores have also been experienced at operations such as the IOC Plant at Sept-Isles, at Lamco and at Bong in Liberia, and in pilot testing of Fabrica ores of Ferteco Mineracao in Brazil. With a grind of about 80-85% -500 mesh resulting in 50% of the particles in the concentrate being less than 15 microns, a discussion of the pro- cessing of Tilden type ores fits the topic of this workshop. There are very large tonnages of fine grained non-magnetic crude ores which exist throughout the Lake Superior District and other iron ore producing regions. These fine grained non-magnetic materials constitute an important source of iron minerals. Before going into specifics of the flowsheet, it is important to

Jan 1, 1979

Iraq Petroleum Co. together have produced more than 2,000,000 bbl. from all areas since 1927, most has been returned to the reservoir through the wells. Iraq Petroleum Company's small skimming plant at kirkuk supplies its operating requirements. Drilling Operations The Iraq Petroleum Co., since 1930, has discontinued exploratory drilling and concentrated on the exploitation of the Kirkrik field preparatory to filling its 84,000 bbl. pipe line. Drilling operations are on schedule and the I.P.C. expects to have its initial producing wells ready to turn into the line by April of this year. The Mosul Oil Fields Ltd., holding company of all the shares in the British Oil Development Co., after acquiring the "West Tigris Concession" in May, 1932, has completed a geological survey of its 46,000 square miles and is entering upon an exploratory drilling program with three cable-tool rigs. Petroleum in Iraq Transferred Territories in 1933* The Khanaqin Oil Co., which operates the Naft Khaneh field in the so-called Transferred Territories, has continued to supply the Iraq market with petroleum products during the period under review. The output of it's refinery at Alwand during the past three fiscal years ending March 31 has been as follows:

Jan 1, 1934

By A. S. Argon, G. East

From their study of the anisotropy of grain boundary mobility in aluminum, the authors conclude that tilt boundaries have a higher mobility than twist boundaries because the atomic misfit at the pure-twist boundary is relatively small compared to the misfit at a tilt boundary for a given amount of misorientation. If this is true, then one would expect a twist boundary to have a lower grain boundary energy than the corresponding tilt boundary. Fig. 6, taken from the work of Gjostein and Rhines,10 shows that this is indeed the case for [001]-cu tilt and twist boundaries in the high-angle region, thus lending support to the authors' conclusion.

Jan 1, 1968

By Hans Lundberq

IINDUSTRY'S attention is now focused on the production of munitions thereby creating a demand for certain minerals which in prewar days were produced only in limited quantities. Now production of these minerals must he increased from the known deposits and new deposits must be found. Can geophysics help? "War minerals" such as tin, vanadium, tungsten, antimony, manganese, chromium, and cinnabar have no physical characteristics sufficiently different front the country rook to permit their direct location by ordinary geophysical methods. As already demonstrated in work on gold and oil, useful information may be obtained indirectly, however, outlining structural features or geological conditions favorable for the deposition of such ores or the accumulation of oil. Recently, more direct and truly qualitative methods have been brought into a useful and practical stage, and by the combined application of old and new methods a technique has been developed which, it is hoped, will be of importance in the search for these vital minerals.

Jan 1, 1941

Today, the employment of the modern hammer drill, using hollow steel, with air or water to expel the cuttings from the drill hole, is the rule rather than the exception in practically all rock-drilling operations. There is considerable carelessness in the matter of keeping the hole in the drill steel properly opened. Plugged steels wholly or partially, prevent proper operation of the drill, whereby drilling speed is retarded, water tubes are bent or broken, and time is lost in tink-ering, or, as often happens, the drilling gang is idle while someone makes a trip to the shop after another drill steel or water tube. To relieve this condition, the Ingersoll-Rand Company has developed, as an auxiliary to the Leyner sharpener, a new device-the Leyner shank and bit punch.

Jan 4, 1918

By Eugene Stephenson

CRITICAL analyses of the work expended in producing oil by the utilization of gas energy have appeared in the publications of Shaw,1 Pierce and Lewis,2 and Herold,3 authors who have ably discussed the factors which must be taken into consideration in comparing energy consumed per barrel in various wells which are flowed by means of gas-lift. However, two distinct phases of oil production are concerned with the ratio of gas energy consumed to oil produced. One of these phases is the gas-lift, which utilizes the differential gas pressures for the purpose of flowing oil, whether these pressures be natural reservoir pressures or be induced by artificial compression of gas or air. The other phase has to do with prorating oil production in pools which are operated either as units, or are subject to such restrictions as those imposed at Oklahoma City by the Corporation Commission, or, by similar controlling groups in other fields. An abundance of literature is available relative to the problems of flowing wells by gas-lift, but the first suggestion that the energy of the gas within the oil and gas pool might serve as a basis for proration, appeared in the timely article by McWilliams.4 Much of the. dissatisfaction with proration in certain fields is because some operators feel that besides the hazard to the wells which accompanies the test, the method of allocating production on the basis of the "potential" gage is inequitable and gives some operators a distinct advantage over others.5 The most severe penalty may be exacted from the most progressive operators or those who attempt to produce their oil with a minimum quantity of reservoir gas. If :no difficulties ever

Jan 1, 1931

By R. J. Colony

DEPOSITS of iron are widely scattered in the folded Cretaceous rocks and the associated igneous intrusives of Puerto Rico. Most of them are too small for commercial development, but a few have aroused some scientific and economic interest, among them the large body of residua] limonite at the west end of the island near Mayaguez1-6 (Fig. 1) and the mixed hematite and magnetite deposit on the southern slopes of the Sierra de Cayey, about four miles north of Arroyo.7-9 Neither of these orebodies has been developed, nor have investigations of the widely distributed deposits of magnetite, which include all the remaining occurrences of iron deserving of economic consideration, proceeded beyond the exploratory stage. With the possible exception of the mixed deposit near Arroyo, the magnetite is directly associated with andesitic and dioritic intrusives, which invade the Cretaceous rock section, and the bulk of it, occurring in calcareous sediments, is clearly of contact-replacement origin. The small deposit on Rio Portugues, north of Ponce, is found in a limestone band near its contact with an andesite dike.10,11 Two deposits of unde-

Jan 1, 1935

By R. W. Smith

Many industries such as the cement industry handle large quantities of limestone and clay slurries. However, at present very little is known about the flow properties, such as friction loss due to flow of slurries in pipelines. This lack of knowledge has made it often very difficult to calculate the total dynamic head of a proposed slurry handling system, and therefore has often made the selection of correct size slurry handling equipment difficult. Because of lack of knowledge about slurry flow a study of slurry flow theory has been made at the Portland Cement Association's Research and Development Laboratory with the idea of developing a method whereby friction losses due to slurry flow may be predicted for any size pipeline. The flow equations developed have been checked by pilot plant size equipment. DERIVATION OF FLOW EQUATIONS It has been known for some time that limestone and clay slurries handled in cement plants do not flow in the same manner as a Newtonian fluid such as water. When a Newtonian fluid flows the shear stress at any flow velocity is proportional to the rate of shear. This phenomenon can be illustrated by a line (Figure 1). The viscosity of the fluid is the slope of the curve. Thus, the flow properties of the material may be characterized by a single materials constant: viscosity. When a non-Newtonian fluid with the type of characteristics exhibited by limestone and clay slurr-ries flow, a similar curve can be constructed (Figure 2). This graph is a shear diagram of a Bingham plastic non-Newtonian fluid. It should be noted that with the Bingham(1) plastic type of flow viscosity, the slope of the curve, is still an important materials constant. In addition, however, there is another materials constant, namely the yield stress of the material. One way to visualize this constant is to consider it as the amount of energy that must be put into a Bingham plastic material to start it flowing.

Jan 1, 1961

By J. H. Bowden

The shaft-plant here described was put in operation in September, 1895, and the No. 6 slope-motor was started in May, 1896. The plant comprises : One Norwalk three-stage compressor l21/2, 91/2 and 5 in. diameters of air- and 20 in. diameter of steam-cylinder, all 24 in. stroke; capacity at 100 revolutions, 296 cu. ft. of free air per minute, compressed to 600 Ibs. per sq. in. A main pipe, 5 in. diameter, 4380 ft. long, with five charging-stations in No. 6 Shaft, and a branch of 3 in. pipe, 3100 ft. long, with three charging stations, in No. 6 Slope. These pipes on each line charge a Porter compressed-air motor, with 7 by 14 in. cylinders, and four 24 in. drivers, weighing about eight tons, with a tank-capacity of 130 cu. ft. of air at 550 lbs. pressure in the main tank, reduced to 160 lbs. in the 8-in. auxiliary tank of 4.2 cu. ft. capacity, supplying the cylinders. The No. 6 shaft run averages 4000 ft. each way on grades of $ to 23/4 per cent., and averaging close to one per cent. in favor of the loaded cars. The No. 6 slope run averages 2100 ft. with nearly the same grades. The mine-cars weigh 2800 Ibs. empty, and about 9800 lbs. loaded, and are hauled in trips of 12 to 20, averaging about 15 cars. The shaft-motor now hauls about 355, and the slope-motor 320 cars per day of 10 hours, replacing in the shaft 17 mules, and

Jan 1, 1901

By G. M. Lee

SEVERAL improvements have been made in Granby smelting practice since the company abandoned the direct smelting of raw ore in the blast furnaces in June, 1927, in favor of sintered concentrate. These improvements have been made in several fields, but the most novel and outstanding change was the development of a process of concentrating most of the gold, and a somewhat smaller fraction of the silver present, in a small portion of the blister copper produced. The practice of making "copper bottoms" is usually associated with the reverberatory smelting of copper ores containing high percentages of impurities, or of copper matte high in precious metals. It has for its object, in the one case, the production of a major part of the copper relatively free from impurities and, in the other case, the production of a small per¬centage of the copper carrying the major part of the precious metals. Although the blister copper produced at the Anyox plant of the Granby company is remarkably free from deleterious impurities and normally contains no great amount of precious metals, certain economic considerations made it advisable to concentrate the existing precious metals into a relatively small percentage of the blister copper produced. The process devised took advantage of principles and reactions of the usual bottoms processes, but was carried out in the converters instead of in a reverberatory furnace.

Jan 1, 1935

By Harry H. Power

WORK of the Committee on Education of the Petroleum Division has been under way for approximately-one year. Although some progress has been made, further activities of the Committee are necessary in order to discuss mutual problems more thoroughly by a unified group interested primarily in this field of specialization.

Jan 1, 1944

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 William Kent

(Read at the Amenia Meeting, October, 1877.) IN a paper by Mr. Frank Firmstone, published in vol. iv, of the Transactions of the Institute, on "Comparison of Results from Open-topped and Closed-topped Furnaces," the regularity of the average grade of pig iron produced by the furnace under different conditions is expressed by means of a curve or diagram. The object of this note is to show that the graphic method, or that of representing variations by plotted curves or diagrams, is capable of a much more extended application to blast-furnace records, making a valuable auxiliary to the "furnace .book," and that by it the practical metallurgist may obtain at a glance information concerning the variations of the furnace during long periods, which could be found in the furnace book only after a tedious search. Plate XII is a graphic record of an anthracite blast furnace for one month. The table on page 554 gives the figures obtained from the furnace book, together with a record of temperature of the atmosphere, barometric pressure, and moisture in the air, which was obtained from a meteorological observatory not far from the furnace. In the records of a furnace, two of the variable qualities are final results, viz., the quantity of pig iron produced, and its grade; all the other variables are antecedent causes which produce the final results. Of these variable causes which contribute to the quantity of product and its grade, some are partially under the control of the furnace manager, others depend upon the state of the atmosphere, and still others are accidental. Of the first class are the character of the materials charged, and their relative proportions, their mechanical conditions, as wet or dry, large or small pieces, etc., the revolutions of the engine, the heat and pressure of blast, and the distribution of the charge. Of the second class are the number of pounds of air blown into the furnace for each stroke of the engine, the amount of moisture in the air, and the condition of the chimney draughts. These vary largely with the season of the year. Of the third. class is the leaking of a tuyere or a temporary stoppage. To keep a record of this kind for a whole year, it is only necessary to procure a sheet of common profile or cross section paper, about 38 inches long and 8 or 10 inches wide, with cross lines ruled about 0.1 of an inch apart. The vertical lines, or those in direction of the

Jan 1, 1878

By Edgar A. Scholz, Attilio G. Spat

The rapid worldwide increase in labor costs, prices of goods and services, and the rising tide of economic nationalism do not bode well for the future of mineral exploration and the mining industry. The increasing complexity and difficulty involved in finding economic mineral deposits makes these trends particularly significant. A comparative cost analysis of domestic and foreign exploration projects which developed into mines during the period 1960-74 may be useful in indicating the general nature of exploration expenditures as these trends continue. This analysis is based on a survey of 18 US and Canadian mining companies. Due to the inexact nature of exploration expenditure data, plus the fact that no two mining companies follow the same system of cost allocation, the results of the survey must be considered quite general in character.

Jan 6, 1977