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By S. C. Sun, D. R. Mitchell

Experiments show that ores such as tungsten and tin, which slime excessively, can be deslimed and upgraded by ultrasonics. The method proposed depends primarily upon the stratifying and peptizing action caused when high frequency sound waves are propagated upward through ore pulp in a cylinder tube. Stratifying and peptizing are somewhat hindered by the accumulating action, which embodies additional effects of reflection and refraction.

Jun 1, 1956

By R. W. Gurry

Thermodynamic calculations indicate that boron is a better deoxidizer than silicon but probably is not quite as effective as aluminum. Boron should, therefore, be readily oxidized out of the open-hearth bath, which implies that it is not recovered in significant concentration from any scrap charged; also that, if added in the ladle, it tends to oxidize out during teeming unless protected by the presence of a better deoxidizing agent. These conclusions do not apply to liquid cast iron, in which the oxygen content is much lower than in liquid steel. The possibility of conserving certain strategic alloying elements widely used in steelmaking, notably manganese, chromium and molybdenum, by the use of boron, which in small concentration appears to be extraordinarily effective in promoting hardenability, raises a question as to what extent any boron present in the scrap charged into the open hearth is oxidized out during melting and subsequent refining. This question is significant because the optimum concentration of boron in the finished steel, which is fairly critical, would be very difficult to attain if the boron in the charge were largely retained in the metal. Moreover, unless boron is substantially eliminated in the open-hearth process its use on a large scale would eventually make it impossible to produce boron-free steel except by restricting the charge to virgin material. There is at present, unfortunately, virtually no satisfactory direct evidence to provide an answer to this question; but there are indications from practice that boron is oxidized out in the open hearth in the production of medium or low-carbon steel, although it may be retained if the carbon content remains fairly high; that is, if the oxygen is kept fairly low. In the absence of direct data, it is necessary to rely upon the indications of indirect evidence, the best approach now available being a thermodynamic calculation of the deoxidizing power of boron in liquid steel by the general method used so successfully by Chipman1 in his study of the reactions in the open-hearth process. The thermal data for boron, upon which such a calculation must be based, are reasonably satisfactory; the only quantities not directly determined are the entropy of melting of boron, the activity coefficient of boron in liquid steel, and the activity coefficient of B2O3in an open-hearth slag; but these values may be estimated with ample accuracy. The results of this calculation, which is presented later, are given in Table I, together with corresponding data for other deoxidizing elements. This table shows the calculated residual content of oxygen in equilibrium with different residual concentrations of the deoxidizer in the metal;

Jan 1, 1944

By R. W. Gurry

Thermodynamic calculations indicate that boron is a better deoxidizer than silicon but probably is not quite as effective as aluminum. Boron should, therefore, be readily oxidized out of the open-hearth bath, which implies that it is not recovered in significant concentration from any scrap charged; also that, if added in the ladle, it tends to oxidize out during teeming unless protected by the presence of a better deoxidizing agent. These conclusions do not apply to liquid cast iron, in which the oxygen content is much lower than in liquid steel. The possibility of conserving certain strategic alloying elements widely used in steelmaking, notably manganese, chromium and molybdenum, by the use of boron, which in small concentration appears to be extraordinarily effective in promoting hardenability, raises a question as to what extent any boron present in the scrap charged into the open hearth is oxidized out during melting and subsequent refining. This question is significant because the optimum concentration of boron in the finished steel, which is fairly critical, would be very difficult to attain if the boron in the charge were largely retained in the metal. Moreover, unless boron is substantially eliminated in the open-hearth process its use on a large scale would eventually make it impossible to produce boron-free steel except by restricting the charge to virgin material. There is at present, unfortunately, virtually no satisfactory direct evidence to provide an answer to this question; but there are indications from practice that boron is oxidized out in the open hearth in the production of medium or low-carbon steel, although it may be retained if the carbon content remains fairly high; that is, if the oxygen is kept fairly low. In the absence of direct data, it is necessary to rely upon the indications of indirect evidence, the best approach now available being a thermodynamic calculation of the deoxidizing power of boron in liquid steel by the general method used so successfully by Chipman1 in his study of the reactions in the open-hearth process. The thermal data for boron, upon which such a calculation must be based, are reasonably satisfactory; the only quantities not directly determined are the entropy of melting of boron, the activity coefficient of boron in liquid steel, and the activity coefficient of B2O3in an open-hearth slag; but these values may be estimated with ample accuracy. The results of this calculation, which is presented later, are given in Table I, together with corresponding data for other deoxidizing elements. This table shows the calculated residual content of oxygen in equilibrium with different residual concentrations of the deoxidizer in the metal;

Jan 1, 1944

TO THE, BOARD OF DIRECTORS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen -The following report covers briefly some of the more important activities of the Institute during the year 1923. In my report for the year 1922, I drew attention to the falling off in membership of the Institute due to the depressed condition of the mining industry in several lines and the inability of many of our members to find profitable employment in mining or its associated branches. A number who were unemployed during 1922 established connections during 1923, but a still greater number have been forced to resign or drop their membership during 1923 Fortunately, the number dropped is not so great as in the previous year. The Employment Service conducted by, the four Founder Societies bears witness to the trend in business For the young men just out of college, there are plenty of opportunities at small salaries, there are plenty of opportunities for them as laborers; but for the mature members, those of experience, there are few calls During the last eighteen months, our Employment Service has been able to place only six of our members out of every hundred engineers for whom it has found work. Another loss which this Society has suffered, but which is not felt so keenly by our sister societies, is in its foreign members. The A. I M. E. has always had a large foreign membership, but of recent years exchange has been so heavily against many European and South American coun¬tries that a large number of members residing abroad have been compelled to relinquish their membership Almost invariably these members express keen regret because of the necessity that confronts them, and almost invariably the writers express hope that present conditions will not last long and that they will soon be able to ask for reinstatement. Having stated the darkest side of the picture first, it may now be drawn to your attention that in spite of these losses the number of persons applying for membership was decidedly encouraging. From the quality point of view, the membership has not gone back¬ward The Membership Committee has declined to recommend many

Jan 1, 1923

By F. G. Cottrell

(New York Meeting, February, 1912.) ABOUT a year and a half ago, at the San Francisco meeting of the American Chemical Society, in connection with the excursions to local smelting-works, I had occasion to show some lantern-slides illustrating the recent commercial development of electrical methods for precipitating the suspended matter from smelter-smoke, the underlying phenomena of which were clearly brought to the attention of the technical public by Sir Oliver Lodge as long ago as 1884. In the Journal of industrial and Engineering Chemistry, August, 1911, most of these views were reproduced, together with an account of the work from its beginning up to July, 1911. To-day I wish particularly to show you some of the further developments of the work since that time; but in order to make these clear they will be prefaced by a brief abstract of the article above referred to. The removal of suspended particles, front gases, by the aid of electric discharges is by no means a new idea. As early as 1824 we' find it suggested by Hohlfeld 1 as a means of suppressing ordinary smoke, and again a quarter of a, century later by Guitard.2 These suggestions, which do not seem to have stimulated any practical study of the question, were soon entirely forgotten, and only brought to light again by Sir Oliver Lodge,3 many years after he himself had independently rediscovered the same phenomena and brought them to public attention 4 in a lecture before the Liverpool Section of the So-

Jul 1, 1912

By Ove Rehnberg

Catalytic purifiers are widely used as exhaust treatment devices on diesel equipment in confined spaces. The paper summarizes some studies carried out at the University of Lulea on diesel exhaust purifiers. The main purpose has been to elucidate important chemical activities of catalysts useful for the improvement of their effect. The effects of platinum catalysts on exhaust constituents such as carbon monoxide, nitrogen oxides, unburned gaseous hydrocarbons, and polynuclear aromatic hydrocarbons are discussed. Also pointed out are the great differences in catalyst activity and advantages/disadvantages associated with the catalysts.

Jan 1, 1982

By H. B. Goodrich

Anthony I?. Lucas died suddenly at his home in Washington, D. C., on Sept. 2, 1921. Captain Lucas, as he was known to us, was born in Dalmatia, Austria, in 1855, of Montenegrin ancestry. He was graduated as an engineer at the Polytechnic of Grate and served in the Austrian Navy as second lieutenant. In 1879, he obtained leave of absence and visited an uncle in the United States. After an extension of this leave of absence, in order to undertake an engineering engagement in the lumber district of Michigan, where he resided, he decided to become an American citizen. He was naturalized in May, 1885. His name was Luchich, but as his uncle had adopted the name of Lucas, which was more easily pronounced by Americans, from his entrance to this country, he used this Anglo-Saxon form. Without knowing this fact, upon first meeting him a person was sometimes surprised to note the rather Germanic pronunciation of the Captain. Although he subsequently revisited Austria with Mrs. Lucas, he made his permanent home at Washington, D. C. His son served with distinction in the A. E. F. during the World War. His activities in this country as a mining engineer were at first in Colorado and later in salt mining at Petit Anse and Belle Isle, La. During his salt investigations, his attention was directed toward the possibility of oil in the Gulf Coast region and in January, 1901, his well, the "Lucas Gusher," on Spindle Top, Tex., started a new era in the oil business and his reputation as discoverer made him famous throughout the world. Captain Lucas became a member of the A. I. M. E. in 1895. During 1914, 1915, 1918, and 1919, he was chairman of the Petroleum and Gas Committee of the Institute and was at all times prominent in Institute affairs. As to the personality of Captain Lucas, the lasting impression is of a courteous hospitable gentleman, genial, affable, obliging, and helpful with his advice br assistance to any colleague. He was sincere, honest, firm against all obstacles, backing his judgment with his own hard work along any course which he had determined to be correct. His value in the engineering world lies mainly in the petroleum industry. In the oil business all wild-catters are pioneers that deserve credit and gratitude upon their success. There are, however, names that particularly stand out in our history. Drake conquered such obstacles as ridicule, lack of finances, and started the oil business. In 1901, Captain Lucas had the conviction that Spindle Top, a dome rising about 12 ft. above the coastal prairie south of Beaumont, Tex., contained commercial oil. He was scoffed at by practical oil men of the East. Noted geologists

Jan 1, 1921

By R. V. Lundquist

Leaching manganese-bearing materials with NaOH to remove caustic-soluble silica has been demonstrated as a method for up- grading manganese. Those materials containing opaline varieties of silica respond most readily. Spent leach liquors are regenerated by treatment with lime to precipitate calcium silicate and to reactivate the NaOH for leaching.

Jan 4, 1953

By I. L. Dillamore

A purely geomentrical analysis based on oriented-growth relationships is presented to derive annealing-texture orientations in bcc metals from their- known deformation textures. The analysis takes as its starting point a description of- the bcc deformation texture and follows previous work on fcc metals in considering pvobable nurleation sites for recrystallization and the textural limitations on grains growing into a deformed matrix. The analy-sis accounts for the prominent and the minor coinponents of the annealing textures formed from two the deformation textures and can account for the ob-sem:ed temperature dependence of the annealing texture of bcc metals. THERE have been a number of investigations of annealing textures in bcc metals but few attempts to relate these textures to the deformation textures. This has been largely due to the lack of definition of both annealing and deformation textures, neither of which shows sharply defined orientations. It is, however, necessary to get a better understanding of primary recrystallization textures in bcc metals in view of increasingly exacting demands upon the quality of steel sheet for drawing purposes and as a necessary step towards the control of textures through processing. An analysis is presented here which relates annealing textures to deformation texture, by a purely geometrical method. This takes as its basis the oriented-growth theory of recrystallization and makes some reasonable assumptions regarding the make-up of bcc deformation textures and the limitations on growth relationships in bcc metals. Detailed information on this latter point is not available at the present time, and the present analysis may need to be streamlined or extended when such information is at hand. It is felt, however, that despite these limitations the analysis provides useful results and a valuable aid towards understanding the effect of processing variables. 1) BCC ROLLING TEXTURES Different workers have used a variety of descriptions for the texture developed in bcc metals by rolling. For the present purpose it will be assumed that two different deformation textures can be obtained: 1) a texture containing a major (112)[li0] component and a minor (001)[1i0] component for which increasing deformation causes the (001)[li0] component to increase at the expense of the (112)[li0] component, as suggested by Dillamore and ~oberts' (this is the texture predicted to arise starting from randomly oriented material); 2) a t~xture containing the above components and (111)[110] and (ii1)[112] components. This texture could arise from a material with an initial (110)[001] or (iil)[112] texture. It is well-known that the (ll0)[001] orientation rotates to (ii1)[112]that on roll-

Jan 1, 1965

By H. K. Shearer

Oil production in north Louisianat in 1939 was 25,249,640 bbl., a decrease of 11.2 per cent from 1938. The only important increases in production were in the Cotton Valley and Shreveport fields, but Caddo, Homer, Sligo and Zwolle also made slight gains. Greatest decreases were in the Lisbon and Rodessa fields. Xatural gas production of 313,333 million cu. ft. was an increase of 5.6 per cent over 1938. The increase was accounted for in the Monroe field, while all other fields showed only minor variations from the production of the previous year. Well completions in 1939, as compared with 1938, were as follows: The decline in number of completions was due entirely to lack of proved areas for drilling, and would have been greater except for a revival of interest in the old Caddo shallow field. A majority of the wells completed during the year were in various old, shallow fields, so the average depth of drilling was much less than in several preceding years, notwithstanding a few very deep tests. No new fields were discovered, the only wildcat well reported as a producer being a very small oil well in northwestern De Soto Parish, which is of no apparent commercial importance. Deep gas-distillate production in the Cotton Valley formation was opened at Lake Bistineau and Lisbon, and oil at Shongaloo, but all these wells were too small to encourage additional drilling. Extensions and Developments Caddo Field.—More active drilling was donc in the 36-year old Caddo field in 1939 than in any of the newer fields, with completion of 133 oil

Jan 1, 1940

By H. K. Shearer

Oil production in north Louisianat in 1939 was 25,249,640 bbl., a decrease of 11.2 per cent from 1938. The only important increases in production were in the Cotton Valley and Shreveport fields, but Caddo, Homer, Sligo and Zwolle also made slight gains. Greatest decreases were in the Lisbon and Rodessa fields. Xatural gas production of 313,333 million cu. ft. was an increase of 5.6 per cent over 1938. The increase was accounted for in the Monroe field, while all other fields showed only minor variations from the production of the previous year. Well completions in 1939, as compared with 1938, were as follows: The decline in number of completions was due entirely to lack of proved areas for drilling, and would have been greater except for a revival of interest in the old Caddo shallow field. A majority of the wells completed during the year were in various old, shallow fields, so the average depth of drilling was much less than in several preceding years, notwithstanding a few very deep tests. No new fields were discovered, the only wildcat well reported as a producer being a very small oil well in northwestern De Soto Parish, which is of no apparent commercial importance. Deep gas-distillate production in the Cotton Valley formation was opened at Lake Bistineau and Lisbon, and oil at Shongaloo, but all these wells were too small to encourage additional drilling. Extensions and Developments Caddo Field.—More active drilling was donc in the 36-year old Caddo field in 1939 than in any of the newer fields, with completion of 133 oil

Jan 1, 1940

By William H. Marlowe, Thomas E. Ban, Eric Johnson

Introduction In recent years, the industries of the US have been caught between ever increasing environmental concerns and an increasing uncertainty in availability of fuel. An obvious solution is to use our vast reserve of coal by direct combustion or gasification. The problem involves development of a fuel that is environmentally acceptable for these purposes. In order to resolve this problem in the shortest period of time, it would be ideal if an existing technology could be modified to produce a clean fuel from coal. Shortly after World War II, the iron ore industry was compelled to develop a high quality ore from low grade resources. This need led to the development of the taconite industry which involved milling, concentrating, and pelletizing technologies. These technologies are now fully established and applicable to conversion of coal. This presentation introduces a process for converting high sulfur coal into carbonized composite pellets, which emit low quantities of sulfur and particulate matter and may be produced by employing proven elements of technology. The new product, a clean pellet fuel (HelifuelTM) was initially developed by McDowell-Wellman Co., a subsidiary of Helix Technology Inc., at their Dwight-Lloyd Research Laboratories

Jan 1, 1982

H. G. KNOX,* Norfolk, Va. (written discussion?).-There is one subject that Mr. Hobart seems to have inadvertently omitted from his very valuable paper, and that is corrosion. The shipbuilder, perhaps more than anyone else, has constantly to guard against it, our chief reliance being paint and galvanizing, where practicable. The corrodibility of a welded. joint is salt water must be determined before deciding whether this type of construction is to supersede riveting. At the present time, this question cannot be answered, although considerable work has been started in an attempt to arrive at a conclusion. The British Admiralty and several British shipbuilders have studied it extensively. Their experiments and conclusions have been very carefully followed and reported in this country by Naval Constructor Goodall of the British Navy. To date, these show that no undue fear need be felt from corrosion. At the Norfolk Navy Yard a series of plates welded with various electrodes were submerged in dilute sulfuric acid, such as is used in cleaning prior to galvanizing. While this test may not be conclusive in any quantitative way, it does show a marked difference in the corrodibility of welds made with different electrodes tinder different conditions. To thaw any conclusions from this accelerated this accelerated test would be, however, ill advised. In riveted joints, the exposed heads and points of the rivets always show the greatest tendency to corrode. This is clue to two reasons: first, as they are raised above the surrounding surface the paint is more susceptible to abrasion; and, second, electrolytic action is set up between rivet and plate. These same reasons lead us to expect a tendency of the welded joint to corrode. Various methods have been suggested for decreasing the probable inherent corrodibility of the weld, in addition to the customary coat of paint. These generally embody the introduction of alloys, principally copper; into the electrode material. Plating the electrode with copper is not effective in that the deposited copper segregates in the weld and actually increases the electrolytic action. As far as is known, no extensive test on the so-called copper-bearing alloy steels, which might be made up into electrodes, has been carried out, but when obtainable, electrodes of this alloy will be subjected to service tests.

Jan 6, 1919

By GEORGE H. DERN

IF THE engineer is to go into politics, as I think he should, I believe the curriculum of every engineering school should be amended to include a good stiff course in public speaking. My observation has been that the engineer in private conversation can scintillate as brightly as a life insurance agent or an oil stock salesman, but before an audience, with rare exceptions, he is a total loss. He will not get up and talk. He hides his light under a bushel, and sits on the bushel as dumb as an oyster. I have seen meetings of the Utah Section at which some topic of general interest to the members was up for discussion, and where an animated debate was the logical thing to expect. After the chairman states the subject and invites discussion, there is dense silence. Finally a member, bolder than the rest, gets up and with trembling voice and knees makes a motion. The motion carries, the meeting adjourns, and then the members gather into groups and begin to discuss the question seriously -and intelligently, giving cogent arguments on either side and embellishing their remarks with appropriate or inappropriate epithets illustrations and figures of speech. Now, I am not pleading for more speechmaking. The good Lord knows we have too much of this great American indoor sport already. But I think every man ought to be able and ready to express his opinions at the proper time. Some men have a reputation for wisdom because they do not talk much. We speak of the wise old owl because she never speaks, but in my opinion the owl's reputation for wisdom is vastly overrated. silence is more apt to be a cloak for stupidity than for wisdom. The person who has ideas can- not exert any influence by keeping them locked up in his own mind. The great motive force of the world is not muscle, but ideas, and ideas in order to get in their work must be released.

Jan 1, 1925

By Thomas J. O’Neil

During the past five years, the mining industry has been subjected to new operating constraints that are unprecedented in number, scope, and urgency. The industry must operate in a safer, cleaner manner, yet produce more without large price increases. Compliance with any new sweeping legislation is always difficult-and particularly so in today's adverse economic climate, which is being aggravated by the steady stream of environmental control and tax-reform programs. In effect, while government is unwittingly but surely undercutting the country's productive capabilities, it blames industry for the resulting failure to meet consumer demand. Any such real or alleged failure then brings heightened bitterness from Congress. During the recent energy shortage, for instance, threats of nationalization were ventilated in public along with proposals to abolish the mineral depletion allowance.

Jan 11, 1974

By Fred Bond

THERE is acute need for a method that will measure the size distribution of finely di-vided materials, particularly when the par-ticle sizes are smaller than the openings of the finest screen cloth regularly available for testing. Several methods and types of apparatus are in common use, but none are entirely satisfactory for all purposes. The commonest methods are microscopic grain counts, elutriation by liquids or air, and sedimentation. Valuable results have been secured by air elutriating devices, typified by the Haultain Infra-Sizer and the Pearson Air Analyzer. These are especially useful in obtaining sized fractions that can be examined and analyzed separately. They are particularly advantageous because the sizes of the sam-ples produced are adequate for a consider-able amount of subsequent manipulation and testing. The sedimentation methods, such as the Wagner and Klein turbidimeters, and the sedimentation balance, do not deliver sized fractions, but they do provide a means for reasonably rapid comparative determina-tions of fineness and surface area, which are important in many industries. The sedimentation balance consists essen-tially of a balance pan suspended in a liquid that contains falling particles. These are weighed as they settle onto the pan, and the time rate of settling is determined. The size distribution is computed from the set-tling rate. The balance appears to be in-herently more accurate than any of the other methods, and it has served a useful purpose in the study of numerous problems, but there have been limitations which have re-stricted its scope of application. Because of the essential simplicity of the method, it was felt that intensive investiga-tion might lead to modifications that would make it a valuable tool for the operators in industries that require precise information regarding the results secured from grinding equipment. A large number of size-distribu-tion determinations below 200 mesh were required in connection with a particular research problem in fine grinding. The sedimentation balance was used, in this investigation, and a technique was gradually developed that ultimately gave good results. A serious difficulty appeared, early in the work. It was discovered that less material always settled on the sedimentation pan and more on the bottom of the containing jar than could he accounted for by calculation, and also that the material that settled to the bottom of the jar outside the edges of the pan was considerably finer than that on the pan. This segregation was so great that the dis-tribution obtained for the finer sizes was obviously very much in error; material ground to about the degree of comminution of cement might have only 60 per cent of the calculated weight actually settling on the pan, and the error increased with the fine-

Jan 1, 1939

By Derek J. Fray, John Chipman

THE solubility of graphite in y-iron has been determined by several workers'12 with reasonable agreement. With the increasing use of more complex steels, it is necessary to understand more fully the thermodynamics of the austenite phase. The activity of carbon in a number of alloys is known but the maximum solu- bility of graphite has only been measured by Sohnchen and piwowarsky3 for Fe-Ni and Fe-Si alloys. Recently, Chipman and Brush reviewed the published data on the activity of carbon in binary and ternary austenite and also obtained expressions for calculating the solubility of graphite in Fe-Ni, Fe-Co, and Fe-Si alloys. On comparing the theoretically derived solubilities with the limited results of Sahnchen and Piwowarsky, it was found that the agreement for Fe-C-Si was excellent but there was considerable discrepancy for Fe-C-Ni and no data for Fe-C-Co. It was therefore decided to measure the solubility of graphite in a series of Fe-Ni and Fe-Co alloys. The alloy samples were made up by induction melting a high-purity master alloy under an inert atmosphere in an alumina crucible and drawing the molten metal into four-bore alumina tubes. Using this technique, it was possible to form alloy rods approximately 2 in. long and 1/18 in. in diam. Sixteen lengths of fine rod could be made without solidifying the master alloy. These were then allowed to cool under the inert atmosphere before being sectioned. The samples were packed in a graphite crucible with spectroscopic graphite powder, together with a piece of pure iron foil. Dry hydrogen, which had been saturated with isopropyl alcohol at room temperature, was passed over the crucible at 1000°C for 72 hr. At the end of the 72 hr argon displaced hydrogen in the reaction tube and the crucible was quickly pushed to the water-cooled end. The samples were thoroughly cleaned of the adhering graphite and analyzed. The pure iron samples always contained 1.5 0.02 pct C, which compares favorably with the data of smith2 and

Jan 1, 1970

By Robert W. Hunt

In 1888 the writer had the honor of submitting to the Institute a paper on " Steel Rails and Specifications for their Manufacture."* In his judgment the specifications were sufficient for "that day and generation." In that paper I said: '' The first duty falls upon the railroad engineer in designing his section. If that is bad, the steel-maker will be heavily handicapped in trying to furnish a satisfactory rail. I suppose it is hopeless to expect the adoption of standard sections."

Jan 1, 1896

By Charles E. Hall

The Crimora mine, operated by the American Manganese Company, Limited, is located 21/2 miles east of Crimora station, 011 the Shenandoah Valley railroad, in Augusta county, Virginia. It is situated in a basin at the western base of the range of mountains which flanks the Shenandoah Valley on the east. This range is composed of the Potsdam sandstone (No. I. of the Pennsylvania survey), and extends in a northeasterly-southwesterly direction the entire length of the valley. The general dip of the measures is westward. The massive sandstone of the mountain is geologically overlaid with shales or slates, which belong to the Potsdam, or lie between it and the Lower Silurian limestone. Throughout this region these shales are decomposed, and form more or less extensive clay deposits, which are found along the base of the range and often underlie a considerable area to the westward of the abrupt slope of the range. Sand and fragments of quartzite occur in considerable quantities on the surface, and often conceal the true character of the underlying formation. The area containing this ore-deposit extends northeast and south-

Jan 1, 1892

Jan 1, 1939