Search Documents

By R. E. Ray, J. W. Stevenson, J. A. Berry

Conventional concrete block plastered with a cementitious coating is the most common material used in the construction of permanent stoppings to direct airflow in underground mines in the US. All mines experience various degrees of strata convergence depending on depth of overburden, geological conditions, and type of roof support employed. Strata convergence will cause cracks and joint openings in masonry stoppings, resulting insignificant air leakage losses. Where strata convergence is severe, complete structural failure of the stopping can ultimately occur. Reconstruction of damaged or destroyed stoppings adds expensive overhead to mining operations, and even greater expenses are incurred from the additional fan horsepower required to overcome leakage losses. Ideally, a stopping should maintain high resistance to airflow while yielding to strata convergence. By properly incorporating a polyisocyanurate rigid foam material within the masonry block structure, stopping service life can be increased in mines experiencing strata convergence problems such as floor heave, roof loading, and lateral rib movement.

Jan 1, 1986

By Eugene McAuliffe

In the year 1581, the counselors of King Philip of Spain suggested to that monarch that a canal across the Isthmus of Darien would open the west coast of the South American continent to Spanish miners and explorers, enlarging and expanding the flow of precious metals then just beginning to trickle across the path cut by Spanish Conquistadors, from old Panama to Puerto Bello on the east coast. The King sent out a party of surveyors and explorers under the command of a young engineer, Savadaerro, who returned after two years, reporting upon a location for a canal which was virtually adopted by the French engineers employed by De Lesseps, who in 1877 commenced the work of constructing the Panama Canal-296 years after Sava- daerro's first survey was begun. The suggestion for an Isthmian canal, made to the king at a time when Spain was a proud, virile nation and when that country was contending with England in the fields of discovery and conquest, represents a measure of vision that has never failed to intrigue the imagination. That the young Spanish engineer recommended an undertaking so gigantic in conception that it took three and one-third centuries for its completion from the time it was first visioned matters little. In the day of Philip of Spain,

Jan 1, 1932

By FRABK HERVEY PETTINGELL

THE stock exchange and its functions is about as well understood by the average individual as the fourth dimension. What is a stock exchange? Divested of the rules and regulations by which it is governed, and the facilities it provides for the convenient handling of securities, it would be in its nude state nothing more or less than a meeting place for brokers. The stock exchange in America dates back to 1752, when a group of merchants of New York established a meeting place at the foot of Broad Street for the purpose of dealing in meal and slaves. The first definite orgarization, however, had its beginning in 1792 when 24 New York brokers signed an agreement not to buy or sell public stock for less than one quarter per cent. commission. From this small group has grown by gradual degrees, the greatest organized security market in the world, namely, the New York Stock Exchange. At the present time there are 27 stock exchanges in the United States and 5 in Canada. Based on the volume of business transacted, the Los Angeles Stock Exchange ranks 6th among them. This is attributable to the fact that strictly speaking Los Angeles has never been a stock exchange town, like some other large cities. Take for instance San Francisco, which supported one stock exchange from 1862 to .1882 and has since supported two. No city, by the way, should tolerate two stock exchanges at the same time. It is an economic folly and a senseless duplication that can be compared with rival telephone companies or competing street railway systems, paralleling each other's lines and always leads to trouble and confusion, and sooner or later one or the other falls by the wayside. While Los Angeles has had stock exchanges of one kind or another since 1896, none of them attracted much attention until 1899 when the present exchange was organized and it did not get well under way until along in 1906.

Jan 1, 1925

By P. J. Closmann

Steam zone growth as a function of time has been calculated for the case of constant rate steam injection into a preheated reservoir. To simplify the calculation a linear temperature profile has been assumed in the cap and base rock at the start of steam injection. The results indicate that at early times augmentation of steam zone growth due to preheating should be greatest. At longer times the steam zone development becomes close to that calculated with no preheating. INTRODUCTION With the increasing application of thermal recovery processes to recover viscous oil, cyclic steam injection has become important in many large-scale projects. In this process, the cycle of steam injection followed by oil production is repeated a number of times. At the beginning of the second and later cycles, steam is injected into a reservoir that has already been heated but that has lost part of its heat both in produced fluids and by conductive heat loss away from the injection zone. In such a case, the temperature level of the injection zone and the temperature distribution of the surrounding rock will affect the growth of the steam zone developed during the subsequent steam injection. Knowledge of the size of steam zone developed is important in determining the amount of oil displaced and the extent of heating in the reservoir. It is also useful to be able to compute the size of the steam zone for cases where thief zones take most of the injected steam. This paper presents a fairly straightforward method of estimating the steam zone developed in a preheated formation, based on certain simplifying assumptions. Some cases of steam injection into a reservoir at its original temperature have already been considered elsewhere.1-3 Because it is difficult or impossible to obtain an accurate representation of the temperature distribution in the reservoir some time after initial heating has taken place, in this work, a linear temperature profile in the cap and base rock is assumed (Figs. 1A and 1B). The linear profile has the advantage of yielding heat flow equations that

Jan 1, 1969

By M. Cross

INTRODUCTION The results of the Japanese dissective investigations have [l-4] transformed our understanding of how the blast furnace operates. These studies revealed an internal structure of the furnace burden with five main zones, as illustrated in Figure 1. In the granular zone the charged material retains its structure whereas in the cohesive zone the iron ore particles are at advanced stages of reduction and form a semi-molten mass with a relatively high flow resistance. In the active coke zone molten iron and slag flow through a matrix of loosely packed coke. The raceway is a relatively small void space generated by displacement of coke due to the hot blast momentum, whilst the hearth is packed with coke, slag and molten iron. [ ] It is now well appreciated that furnace control is largely achieved and maintained by using the burden charge distribution to determine the gas glow distribution within the furnace and, hence, the shape and extent of the cohesive zone. In fact, Wakayama et a1 [5] of Nippon Steel Corporation state that optimum furnace operation is synonomous with the formation of a desirable cohesive zone shape, which in turn is almost solely determined by the burden charge distribution and its mechanical properties [6]. Much of the development work on operating furnaces since the dissective investigations has been oriented towards the identification of external furnace measures which reliably predict the shape of the cohesive zone. Currently the most popular measures are top gas temperature, velocity and CO/CO, ratio profiles [5]. More recently pressure distributions as evaluated from a series of wall measurements down the height of the furnace are also being utilised [7] to identify the position and shape of the cohesive zone. A great deal of emphasis has been placed upon achieving a consistent quality in the burden charge materials, establishing a suitable set of operating conditions and only making changes when forced to, ie., the operation for some reason moves outside a desired operating range or the production requirements change. Operational control schemes based upon this philosophy (eg., Kawasaki's GO-STOP system [8]) have been remarkably successful at achieving both high production rates and relatively low fuel costs. Mathematical models have long been used as tools to assist in the analysis of the blast furnace process. Although, the models have been useful in post-operative analysis and for identifying trends, etc., they have not proved reliable for detailed design criteria or as the basis for effective control schemes. Such mathematical models have moved from simple statistical correlation, through overall and stagewise heat-and-mass balance calcu-

Jan 1, 1984

ENGINEERS AVAILABLE (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Member, technical graduate, aged 36. Experienced copper metallurgist and mining geologist. Familiar also, through 15 years' broad practical experience, with mining, cyanidation, concentration (including oil flotation), metallurgical accounting, and mine and plant management. Best references. No. 237. Member, graduate engineer with 10 years' experience in malleable, gray -Iron, and steel, as chemist., metallographist, and metallurgist. Researches and investigations by laboratory methods and under works conditions. No objection to some routine. No. 243. Member, technical graduate, broad experience in coal, oil, and clay. Will go anywhere as mining geologist after Sept. 1, 1915. No. 244. Member, technical graduate, aged 30, married, with over 10 years' experience as chemist, engineer on construction, superintendent and general superintendent of bituminous coal and coke plants. SpeaksSpanish. References. No. 245. Member, open for engagement as mine safety inspector or as superintendent of bituminous coal mine. No. 246. Member, graduate mining engineer, with five years' experience in coal mining as mining engineer, construction engineer, pit boss, and superintendent, open for engagement. Best references. No. 247.

Jan 9, 1915

By William B. Plank

IN this paper are presented the results of a complete statistical survey of the enrolment, courses and degrees, and the employment situation of recent graduates in all of the 46 institutions in the United States, including Alaska, and four of the six schools in Canada that grant degrees in mineral technology. The data were collected by the writer by means of a questionnaire in December, 1933, to which all the institutions, except one, replied. Included also are data of a similar study made by the writer in May, 1933, for the S. P. E. E. summer session of mining and metallurgical teachers at the University of Wisconsin and published in the Journal of Engineering Education for December. 1933. Some of the data of a paper of the writer's entitled, "The Trend of Mineral Engineering Student Enrolment in the United States," read at the A. I. M. E. meeting on Feb. 16. 1931, are given for comparison. Acknowledgment is made to all the administrative officers of the institutions who took the time from their busy lives to supply the in- formation asked for. Their fine cooperation has alone made possible these two surveys with a completeness of detail never before attempted

Jan 1, 1934

By A. W. Ruff

The seismic wave produced by an explosive is very important in blasting. A true understanding of the wave is only important when considering possible structural damage to buildings located near the blast, but it is also of primary importance when considering rock fragmentation. Because of the importance of the seismic wave to fragmentation, a finda-mental study of the seismic wave and its effect was made at the Cananea Consolidated Copper Co.'s mine at Cananea, Sonora, Mexico. Strain gages were used to measure the strain in the rock when nearby explosive charges were detonated. The variance in the circuit voltage caused by changes in the resistance of the strain gage was measured with an oscilloscope and recorded with a Polaroid camera. CONFINED DRILLHOLE CHARGES To record the seismic wave from a confined drillhole explosive charge, a gage was cemented to the bottom of a 4-in diam drillhole. The horizontal gage hole and nine horizontal charge holes were drilled perpendicular to the center line of the 2-39 drift and 4 ft above the floor. The gage hole was 29 in. deep, and the charge holes were drilled so that each bottomed 1 in. deeper than the gage hole. The gage was installed with its axis horizontal and parallel to the 2-39 drift. The charge holes had the following horizontal distances from the gage: hole 3, 3 ft; hole 4, 4 ft; hole 5, 5 ft; hole 9, 9 ft; hole 10, 10 ft; hole 14, 14 ft; and hole 15, 15 ft. Figs. 1 and 2 show the relationships of the gage and the charge holes. Charges of 80 pct special gelatin, which weighed 50, 100, and 150 g were exploded in the charge holes and the seismic waves were recorded. All charges were stemmed with 200 g of mud and detonated with an electric blasting cap. Fig. 3 shows the recorded seismic waves. The reflected components of the waves were too weak to be objectional on these records. Table I shows the data taken from the wave forms. The approximate average velocity of a wave with a 9-ft travel distance was 12,900 fps. Since different charge weights were used, it was necessary to scale the data. The scaled maximum compress ion-strain data and the scaled maximum tens ion-strain data are shown in Figs. 4 and 5, respectively. Figs. 6 and 7 show the strain-distance data from Figs. 4 and 5 converted to a 1-lb charge. The results showed that the wave consisted of an initial compression pulse followed by a tension pulse. The amplitude of the tension pulse approached the amplitude of the compression pulse as the distance between the gage and the shot increased. The decay rate of the seismic wave is very important in the evaluation of the blasting characteristics of a rock. When high-amplitude stresses are produced, as in rock fragmentation, the rate of decay is much more rapid than when small amplitude stresses are produced. In underground mine blasting, the burdens are usually not greater than 6 ft and the decay is very rapid. The rapid seismic-wave decay rate in the fragmentation range means that in practice, if the minimum weight of powder is used to break a specified burden, only a very

Jan 1, 1961

By S. A. Swensrud

NINETEEN Thirty-Six was the biggest year in volume in the history of the oil industry, and unquestionably the best since 1929 in respect to profits. The quota of new and difficult problems to face seemed a little smaller during 1936 than in most recent years, and a somewhat better balance existed between the different branches of the industry. 'Domestic consumption of gasoline in 1936, estimated at about 475 million barrels-the highest on record, was approximately 11 per cent above 1935, and 26 per cent above 1929. Demand for crude oil increased in about the same proportion: over 1935, and the average production, of about three million barrels daily,' constituted a new high level.

Jan 1, 1937

By Charles R. Fettke

In connection with the gathering of data for a report on the geology of the Humacao district of southeastern Porto Rico during the summer of 1916, under the auspices of the Scientific Survey of Porto Rico and the Virgin Islands, conducted by the New York Academy of Sciences, the writer had an opportunity to make a brief examination of the magnetite deposits of the eastern portion of the island. Inasmuch as these deposits have attracted some attention as possible future sources of iron ore, and as there is only scanty reference made to them in literature,' a short description based on this reconnaissance survey was deemed to be worthy of record. The magnetite deposits of eastern Porto Rico occur in association with a belt of limestone, trending approximately S 53° E, which begins 11/2 miles east of Juncos and can be traced for about 6 miles toward the coast. Four outcrops of magnetite were observed, which are designated as Nos. 1, 2, 3, and 4, respectively, on the map shown in Fig. 1. Others are probably present, but escaped notice on account of the thick mantle

Jan 1, 1924

By AIME AIME

A discussion of the Papers by Prof. H. Hubert, Liege, Belgium ; Mr. Tom Westgarth, Middlesbrough, England ; and Mr. K. Reinhardt, Dortmund, Germany, presented at the London Meeting, July, 1906, and printed in Bi-Monthly Bulletin, No. 12, November, 1906; pp. 910 to 930, 971 to 987, 1037 to 1163. MR. ADOLPH GREINER, Seraing, Belgium :-I have nothing special to add to Professor Hubert's paper except to say that there are some little things that it would be well to have cor-rected when the paper comes to be published. In dealing with the thermal efficiency of the engine, you will find that the 29.84 per cent was a very high one. Professor Hubert has forgotten those engines built under the Cockerill type, but he has referred to them in Appendix II. At our works at Cockerill we have built 63 engines, giving 63,000 h.p., and the other companies who have received licenses have built 113 engines, making 103,000 h.p., and aggregating 176 engines and 166,000 h.p. Eight years ago I had the pleasure of giving to the Institute the results obtained up to that time. Since then a good many engines have been constructed. In 1898 I thought a blast-furnace producing 100 tons of pig iron would allow 3,000 h.p. Professor Witz and Professor Hubert show that with the same production of pig the new engines take 3,800 h.p. out of the gas. At present at Cockerill we make 700 to 800 tons of pig iron per day, and we hope to have 26,000 h.p; in a few years. At present we have only half of that in gas-engines, but we hope to have in five or six years all the gas out of these furnaces to the number of 25,000 or 26,000 h.p. MR. Tom WESTGARTH, Middlesbrough, England:-My contribution is not a paper in the ordinary sense of the word, because I am sure you will agree with me that what I have written is only supplementary to the other two papers. The notes are schedules of the larger-size gas-engines built by the engine-makers, of 500 h.p. and upwards. If you look at the schedules you will find that in England gas-engines have be-

Jan 1, 1907

By B. A. Rogers

IN addition to the usual methods of manufacturing steel, a number of special processes have been the subject of considerable experimentation-and use in manufacturing practice. A number of these methods have been of a type in which a rapid refining action has been secured through the intimate mixture of fluid slag with fluid metal. The persistence with which more rapid methods are sought is indicated by the current interest in the Aston' method for producing wrought iron and in the Perrin2 process for dephosphorizing and deoxidizing steel. In the Perrin process, in particular, the mixing action is extremely vigorous and the reactions proceed with surprising speed.

Jan 1, 1936

By J. C. Bokros, A. S. Schwartz

The irradiation-induced densification of pyrolytic carbon has been shown to take place by a simple first-order rate process. The values of the densification constant, kd, for isotropic carbons are 1.0 x 10-22, 1.4 X 10-22 and 2.8 X 10-22 (nut)-1 at irradiation temperatures of 520o, 670°, and 1000oC, respectively. The apparent activation energy obtained from the temperature dependence of kd for isotropic carbons is about 0.2 ev. Estimates of the maximum stresses that develop in isotropic carbons owing to shrinkage onto an unyielding support show that stresses in excess of 15,000 psi may be avoided during irradiatian at 600" and 1000°C if the initial coating density is kept above 1.5 and 1.9 g per cu cw, respectively. If a carbon coating on an unyielding support is not completely isotropic, stresses may continue to build up at high neutron exposures after densification is complete because of continued anisotropic distortion. Stresses in excess of 15,000 psi from this source may be avoided during irradiation at 1000°C if' the Bacon anisotropy factor is kept below 1.3. A variety of applications of carbon and graphite in nuclear technology has stimulated numerous studies of the effect of neutron irradiation on these materials One of the most interesting problems associated with the use of carbons and graphites in the high fast neutron fluxes of nuclear reactors arises as a consequence of the neutron-induced dimensional changes that occur during irradiation. Energetic neutrons displace car- bon atoms from their lattice positions; and, depending on the temperature, the interstitials and vacancies produced migrate to form clusters, recombine, or are annihilated at dislocations or crystallite boundaries. The competition of various sinks for the point defects results in structure-sensitive bulk-dimensional changes that vary with temperature in a complicated way. This paper deals with the neutron-induced dimensional changes in turbostratic carbons that are being used as coatings on nuclear fuel particles. Details of the structure of these carbons and the variations of their structure with deposition conditions have been reported.'-3 It has been shown in previous work that the neutron-

Jan 1, 1968

By W. F. Rochow, W. C. Burke

Numerous designs of linings and accessories, including dams, lifters, and heat exchangers, contribute greatly to kiln efficiencies. Greater conductivity is achieved with basic brick than with fireclay and high-alumina refractories, depending largely upon the use of steel plates in radial joints between adjacent brick to increase heat transfer through the lining. Refractory lifters expose all portions of the load to radiant or convective heat and raise some portions to higher temperatures by cascading the load down through the path of the hot gases.

Jan 3, 1955

By O. G. Lellep

Modern shaft kilns in Europe are fully mechanized and burn cement of acceptable quality at 700,000 Btu per bbl and lime at 3.2 million Btu per net ton. Rotary kilns for cement have increased in thermal efficiency by using exit gas heat for preheating incoming raw material and by recovering heat from outgoing clinker in air-quench coolers. The dry process Lepol or ACL kiln has the lowest fuel consumption, 580,000 to 630,000 Btu per bbl, and very low dust loss, about 1 pct weight of clinker. The Holdebank-Gygi system reaches 720,000 Btu per bbl. The calcinator kiln for the wet process consumes 1.1 million Btu per bbl. IN every country economic circumstances prescribe the method used to produce a commodity at lowest cost. In Pennsvlvania a man's wages for working 4 hr buys a ton of coal wholesale; in Germany a laborer must work 40 hr, or ten times as long. In western Europe, therefore, conservation of fuel is of primary importance, and recent practices of burning lime and cement differ from those employed in the United States. 'This Paper presents data collected during a trip through western Europe in 1953. Considered uneconomical, shaft kilns for burning

Jan 1, 1955

Jan 1, 1966

By S. M. M. Safvi, A. Jowett

Small-scale continuous flotation tests are described in which the influence of 1) pulp density and 2) feed rate on the rate of flotation are investigated. The results provide further evidence of first-order kinetics for flotation and indicate that tests at different feed rates provide a particularly simple method of determining rate constants. Flotation kinetics are discussed in general terms. Over a period of many years numerous research workers have studied the rate of recovery of valuable materials from flotation pulps with a view to deter-mining the mechanism of the froth flotation process. Froth flo ation is fundamentally a collision process involviug at some stage collision and then mutual attachment between air bubbles and mineral particles. It is possible to draw analogies therefore between the flotation process involving mainly macroscopic particles and the ordinary processes of chemical reaction kinetics involving collisions between atoms, molecules and ions. By adopting this analogy we may postulate a general equation representing the kinetics of the flotation process: -dC/dt =K.CC ,Aa (1) The rate constant, K, will be a complex function involving reagent concentrations, particle and bubble sizes, induction times and no doubt flotation cell design. However, these are factors which can be kept constant in any series of experiments, permitting investigation of the exponents a and c, which determine the order of the reaction occurring in flotation. The various research investigations carried out so far have all aimed at evaluating a and c and in the majority of cases only since the concentration of air has usually been kept constant in a series of tests, so that a relationship of the following type has been investigated: -dC/dt = K1 Cc (2) The techniques of both batch testing and continuous testing have been used to investigate this relationship. The technique of continuous testing, in which steady-state conditions are established, permits direct investigation of the above equation. In the case of batch testing, C is decreasing continuously

Jan 1, 1961

By J. C. Osmond

One of the least known geologic regions in the U.S. is the area now called the Basin and Range Province. It is paradoxical that so little geologic information has been compiled for a province that has yielded billions of dollars worth of metals and is currently producing a small amount of oil. Regional stratigraphic studies of parts of this large territory have been published only recently, and regional structural interpretations of even parts of the province are rare in the literature. This, of course, does great injustice to the earliest workers: Gilbert,1,2 Russell,9 Le Conte,4 Spurr,5 Louderback,8 and others, who recognized the area as distinctively different from the rest of North America. Their simplified picture of the structure of the ranges and the province as a whole is the groundwork for present understanding and has never been superseded. Since their early works, however, geologic data from the province has consisted largely of detailed reports of widely scattered mining districts. Each district has been described as though it were an island in an unknown sea. More recent syntheses of the geologic history have been prepared by Lindgren,7 Ransome,8 Nolan,9 Bill-ingsley and Locke,30 Longwell,11 and Eardley.12 The tentative nature of the present interpretation, which treats the structural evolution of the Utah and Nevada area, must be considered in light of the scarcity of geologic information from the province as a whole. The methods of interpreting tectonic history from stratigraphy are based largely on the concepts of Marshal Kay.23 Discussions with Hoover Mackin also have aided in organizing the Tertiary history. TECTONIC AND STRATIGRAPHIC SETTING Two approaches to the subject of the tectonic history are possible; they correspond to looking through opposite ends of a pair of binoculars. One involves an expansion and extension of detailed work and the other an interpretation based on regional geological relationships. It is believed that the second approach, used here, is not in disagreement with detailed observations. The area of the Basin and Range Province is shown in Fig. 1. Within this area middle Tertiary to Recent high-angle faulting has controlled development of mountain ranges and valleys. Only the part of the area north of Las Vegas, Nev., and south of the Snake River in Idaho will be considered in this article. Within this part of the province most of the ranges trend north-south. Approximately two thirds of the area is covered by late Tertiary to Recent valley fill and lake deposits.

Jan 1, 1961

By W. T. Swensen

The Anaconda Company, through its wholly owned subsidiary The Anaconda Company (Canada) I,td., has investigated, optioned and partially developed a large tonnage of iron ore amenable to magnetic concentration. The reserves are located in north central Ontario and occur within a twenty-two mile belt of layered and intricately folded metamorphic rocks, close to the north contact of an igneous complex of granite and pegmatite. There are two main ore deposits. Briarcliffe is a steep to vertically dipping body 100 to 500 feet wide and over a mile long. The Two Mile Lake deposit is flat dipping and confined to an open, asymmetrical syncline; it is approximately a mile wide and 250 to 4.00 feet thick. On its flat easterly plunge, it is saucer-like in shape and is amenable to open-pitting for an east-west distance of several thousand feet. Magnetometer surveys, confirmed by drilling, indicate at least a three mile eastward extension of this deposit. Location and Access: The property is located in the Kowkash Mining District of northwestern Ontario, roughly forty-four miles north of the community of Nakina on the main line of the Canadian National Railroad. (Fig. 1) Access during the exploration period was entirely by airplane from Nakina. (Fig. 2) More recently, Nakina itself was connected to the highway network in the Longlac-Geraldton area. The property is roughly 190 miles by existing and proposed railroad from the Great Lakes waterway system. The Trans-Canada pipeline moving natural gas from western to eastern Canada passes through Geraldton roughly 70 miles south of the property. Topography: The surface features in the area are typical of a sizeable portion of the Precambrian Canadian Shield area. Many lakes, low swampy areas, and glacial moraine-type features are common in this recently glaciated area. The average elevation is between 800 and 900 feet above sea level, and the relief is probably less than 100 feet with the greater portion of the area less than 50 feet. The topographic "highs" are formed either by outcrops that were resistant to glacial erosion or by moraines, eskers and drumlins which were deposited upon the recession of the glaciers. The better mineralized zones, composed chiefly of quartz and magnetite, commonly form ridges resistant to erosion and weathering. Previous Work: Because of the obvious outcrop of the magnetite-rich beds and knowledge gained from early developments within the general region, it is conceivable that the presence of the iron formations has been known for a good many years. The area is included in studies made by L. F. Kindle* in 1929 and 1930 for the Ontario Department *Kindle, L.F., Kowkash-Ogoki Gold Area, Ontario Department of Mines Annual Report, Vol. XL, Part IV, 1931; map 40f

Jan 1, 1961

By C. M. WEILD

ATTENTION has been turned recently to the exploration and development of certain large blanket-deposits of brown iron-ore in Cuba. The most conspicuous of these to-day, and the one upon which the most light has been shed, is the Mayari deposit, situated about 15 miles south of Nipe bay. Here the Spanish-American Co. has sole control over 18,500 acres of ore-bearing lands, reported by its engineers to contain 500,000,000 tons of ore; and the necessary plant and equipment, with docks and railways, is now under construction for the early marketing of this ore. A similar deposit, and undoubtedly the next to be exploited, is the ore-field at Moa bay, where 13,000 to 15,000 acres of ore-lands, immediately adjacent to the shores of an excellent harbor, have been generously covered by numerous mining-claims, practically all controlled by four large interests. This deposit is now estimated to contain approximately 350,000,000 tons, on the basis of dried ore ready for shipment, a figure which may be increased when the western limits of the ore-deposit have been more accurately defined. Other deposits of the same type, but smaller and less accessible, are those at Cubitas, situated from 12 to 15 miles north of Camaguey city, and at Taco bay and Navas, points lying a few miles west of Baracoa. The area of the Cubitas deposit is said to be 6,000 acres, and the yield of ore is estimated at 150,000,000 tons. The Baracoa. deposits are less well known, but preliminary estimates have placed their joint ore-reserves at 40,000,000 tons. Accepting the above tonnages as reasonably correct, we conclude that the deposits enumerated give promise of adding about 1,000,000,000 tons of iron-ore to the world's supply; they have, therefore, to be considered in any attempt to fore-

Aug 1, 1909