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By Robert Livermore

IT has been a noteworthy feature of the Cobalt camp, that many of the valuable ore deposits have been covered, wholly or in part, by small but usually deep lakes, such as Cobalt, Cart, and Peterson lakes, and with the subject of this article, Kerr lake. In the early days of the camp many water-covered areas, which have since been found to be valuable, were ignored, or neglected by owners, or simply perfunctorily staked for water rights. Kerr lake is probably the evidence of a fault or sharp fold, having a general east and west strike, and containing a series of ore-bearing fissures, parallel generally to the strike, although having some notable exceptions to the general rule. On the north side of Kerr lake the formation is of diabase, while on the south side it is of Huronian slates and conglomerates. These Huronian measures extend out under the lake, dipping gently to the north to a lateral distance not yet definitely determined, owing to the lack of development under the deepest parts of the lake. Probably the contact between the diabase and Huronian or else between the former and the .underlying Keewatin formation occurs somewhere near the center of the lake. Kerr lake originally covered 45 acres. Of this the Kerr Lake Mining Co. owned 12, the Drummond Mine, 7, and the Crown Reserve Mining Co. the remainder of 26 acres. Since the latter's property was originally entirely under water, it was necessary for the owners to make land for buildings and shaft room. Accordingly, in 1908, a trench was blasted out which deepened the outlet, and lowered the lake 8 ft. As many of the rich veins of the Crown Reserve and Kerr Lake companies were under water, mining was pursued under some disadvantages. Fortunately the rock is tight and solid, and mining has been done sufficiently far from the surface to avoid unnecessary risk. Nevertheless, there was always danger of encountering open seams, through which too large a flow of water for comfortable working might come. Careful soundings were made over the veins, y means of steel-shod pipe, through mud and water to bedrock, but there was sometimes an element of uncertainty as to whether actual bedrock had been reached. Furthermore, the necessity of leaving safe backs between workings and lake tied up large quantities -of-ore, -and- made development- in certain

Jan 7, 1914

THOMAS T. READ, Palmerton, Pa. (communication to the Secretary*). -It is much to he regretted that in presenting a further discussion of these deposits, first described by myself' and later discussed by C. M. Weld,2 Mr. Wang bas not made a more complete presentation of the evidence on which he bases his conclusions as to their origin. Mr. Weld said in his paper that his visit was confined to a few hours, that he saw only one of the several exposures, and that he took away no samples for further study. My own visit was brief, and for another purpose than the study of the geological features of 'the deposits, so the fact that Mr. Weld described as a hornblende-granite the rock which I described as a "dark gray syenitic rock," and which Mr. Wang identifies as a hornblende-syenite, seems of no great importance, since this rock is generally decomposed along the contact, presumably the only place in which Mr. Weld observed it. Later in the same paper (p. 31), Mr. Weld says that his opinion is that the magnetite of the deposits is primary, but Mr. Wang makes no mention of this in stating his own conclusion to the same effect. When Mr. Weld's paper appeared, I did not discuss it, because, although I considered the evidence- that he brought forward to support his belief that the magnetite is primary too slender to support the hypothesis, my own evidence to the contrary was equally tenuous. .The opportunities for observation and study open to Mr. Wang must have provided him with

Jan 6, 1917

J. J. MCLELLAN, Webb City, Mo.-The Media mill, at the time it was built, was the largest mill that had been designed in the Joplin district. It was put up in a hurry, to take advantage of the high prices for zinc ore in 1915, by the owners of an adjacent plant, which had been very profitable. They owned a compound Corliss engine, and to take advantage of a single-unit drive it was necessary to build the mill in the form chosen, which involved making the hopper feed directly through the breakers and rolls, the undersize from the screen passing at once to the jigs, the oversize going through the rolls and returning to the original trommels. The mill was built in fairly good proportion; crushing was done by jaw breakers, Webb City pattern,' and three sets of 42-in. (106.7-cm.) Cornish rolls for reducing the oversize. The jigs were larger than the usual practice. The roughers were two six-cell jigs, with 42 by 48-in. cells. The cleaner jig was the largest ever constructed in the district up to that time, having seven 36 by 48-in. cells, for treating the rougher jigs. There was also a chat rougher. "Smittem," as used in our district, is the partly concentrated product from the rougher, which is finished on the cleaner jigs. "Chats" are the middlings proper, that is, they are the grains of chert with included particles of sulphide; the very low-grade smittem is sometimes included among the chats. When drawing chats from a jig, we also draw about ten times greater quantity of barren chert in order to insure complete recovery of mineral. This mixture of middlings and tailings is taken to a set of 30-in. rolls, the crushed product then going to a chat rougher, a comparatively small jig, with 26 by 36-in. cells. The principal departure of the Media mill from the usual practice was to build a hopper sufficiently high to give gravity feed to the jigs, without using elevators. The sludge plant, for table treatment of sand and slime, also contained several innovations in the manner of distributing the feed. The tables were arranged in two rows and the feed ran around the outside in a launder having two or three cone classifiers

Jan 1, 1918

By O. W. Ellis

THE writer has dealt with the effect of various methods of melting copper upon the gas content of the metal.1 The copper referred to in his in his earlier paper was melted in the foundry both in the oil furnace and the electric furnace. As the metal, did not measure up to conductivity FIG. L -INGOT OF OVERPOLEP COPPER. standard, the term "casting copper" was applied to the material in the title of the paper. It was thought that some information in regard to the gases in a sample of overpoled copper might also be of interest, and through the courtesy of C. R. Stevens, superintendent of the copper mill of the Westinghouse Elec. & Mfg. Co., such a sample was obtained. The metal was chill-cast in the form of an ingot about 7 in. long, 2 ½ in. deep (from the base to the raised surface of the ingot) and from 1 3/8 to 1 7/8 in. wide. A photograph of part of the ingot is shown in Fig. 1. The effect of overpoling on the surface of the metal is here quite clearly shown.

Jan 1, 1929

By H. M. St. John

MAINTAINING a satisfactory structure in brass and bronze castings has always been a foundry problem of great practical importance. While metallurgists and scientific investigators have not entirely ignored this matter, it has received less of their attention than has been given to iron, steel and the wrought copper and aluminum alloys. Investigation in this field has probably been discouraged to some extent by the complicated nature of the alloys involved. Hundreds of alloys are in more or less common use, most of them containing copper, zinc, lead and tin in-widely varying proportions. They also contain appreciable percentages of iron and antimony as impurities, and often phosphorus, which has been added as a deoxidizer and fluidifier. Small amounts of sulfur are usually present. It is not uncommon to find nickel, sometimes in rather substantial quantities. Traces of other metals are frequently present. So complicated and variable a mixture obviously offers difficulties in. any investigation of the various factors that influence the structure and other properties of the casting.

Jan 1, 1930

By R. P. Rothwell

IN January last I published in the Engineering and Mining Journal a table giving, with a considerable degree of accuracy, the production of anthracite coal for the year 1874. At that time it was impossible to give any correct estimate of the production of bituminous coal, for the returns I had been able to secure from such distant and scattered districts were not always forwarded punctually, and the work of -obtaining anything like a true estimate of the coal mined in districts from which I was unable to obtain official returns was both laborious and tedious. As will be seen from the detailed reports furnished herewith, I have succeeded in obtaining tolerably accurate returns of 20,093,704 tons; and upon careful revision by numerous well-informed local authorities, my first estimate of the amount of coal not officially returned to me has grown very considerably; indeed, as I get more information on the subject I find that our bituminous coal production greatly exceeds the amount we have been accustomed to hear it placed at, aggregating as it does, 26,465,704 tons. Mr. Andrew Roy, State Inspector of Mines for Ohio, has reported the production of Ohio at 4,168,445 tons, while his first estimates were but 3,820,000 tons; and similarly, in other cases, the more full the returns direct from the mines the more incorrect do I find all previous reports. I am able now to furnish, not an accurate statement, indeed, but by far the most full and reliable one that has yet been published of our coal production. The amount of labor involved in obtaining this admittedly imperfect report has been simply enormous. In the following tabular statement it will be perceived that Pennsylvania produces nearly one-half of all the bituminous coal mined * Since this paper was read fuller reports from some of the States whose production had been "estimated" have modified the figures given. The most serious error is in California, which produces probably 200,000 tons less than these figures. Oregon and Washington territories also yield smaller amounts than here reported; but these reductions are probably fully compensated by fuller reports from other States that were here underestimated. The correct aggregate amount will not vary much from that here given. Early in 1876 I will be able to give a fuller and more accurate report for the year 1875.

Jan 1, 1875

By William Waters Van Ness

The Pierrefitte mines, situated in the South of France, in the district of the Hautes-Pyrenees, owe their name to the fact that the first mining operations of any extent, and of comparatively reccnt date, were carried out in the neighborhood of the village of Pierrefitte, which is a branch terminus of the Midi railway. The Pierrefitte mines, however, embrace a wide extent of country and several different concessions, on most of which comparatively little exploration-work has been done. The portion of the property presently to be described is a zone running roughly E—W., over a distance of about 5 miles from the valley of Cauterets to the valley of Estaing, the ridge dividing these valleys being a spur of the main chain of the Pyrenees, and running more or less at right angles to it. According to local tradition, which various indications tend to confirm, these mines are of ancient date, the first workings being attributed to the Romans, who are supposcd to have sought not only the lead but also the silver which is contained in the ore. Old slags have been found in the neighborhood which might well have been produced from the cupellation of lead-ores. These old workings, while of considerable extent at times, do not seem to have extended beyond a depth of 100 ft., even this depth being somewhat exceptional. The old notarial records of the district show that mines were known to exist, and that they were even worked, in the sixteenth century, but since the mines were abandoned (by the Romans or others) considerably prior to this period, very little

Jan 1, 1909

By Charles E. Barker

Jan 1, 1985

By R. E. Tate, L. J. Herman

We have had occasion to produce wire of Np-237 in small diameters for use in some chemical experiments. Since the mechanical metallurgy of neptunium has not been investigated extensively, it seems desirable to report our successful extrusion technique. Because of the neptunium activity and its attendant health hazard the experimental work was done in glove boxes and related equipment also used for Pu-239. At room temperature a phase neptunium' is a hard (Dph -355) orthorhombic metal of high density (p = 20.45 g per cu cm). a neptunium transforms2 to tetragonal ß neptunium at about 280°C and this in turn transforms to bcc y neptunium at about 577°C. The y phase melts at about 637°C. A temperature of 340° to 345°C was selected for the extrusion, this temperature being a compromise be- tween a possible advantage of working with the presumably more plastic cubic y phase above 577°C and the risk of having the neptunium react with the alloy steel die to form the low-melting Fe-Np eutectic. A 0.75-in.-long, 0.26-in.-diameter ingot of good-purity* Np-237 was extruded by the direct *C = 230 ppm, Pu = 200 ppm, thirty-five metallic elements below limit of detection by spectrographic methods. process through flat-face orifices to form several sizes of wire ranging from 0.010 to 0.030 in. in diameter. Molybdenum disulfide was used as the die lubricant. The extrusion was done in a vacuum of about 10-4 torr to reduce reaction of the neptunium with atmospheric gases. British workers3 at Harwell have extruded neptunium under similar conditions. The force required to extrude 0.010-in.-diameter wire at the rate of 4 in. per min was 6000 lb, as measured with an electrical load cell. Wire 0.020 in. in diameter was extruded with a force of 4700 lb at a rate of 2 in. per min, and wire 0.030 in. in diameter was extruded with a force of 4000 lb at a rate of 1.3 in. per min. An extrusion constant, c, can be computed from the measured forces, P, for the equation4 P = c log-A/a where A/a is the extrusion ratio or the ratio of the cross-sectional areas of the container and the

Jan 1, 1965

By M. F. Trice

Pyrophyllite is a hydrous aluminum silicate (A1²Si4O10(OH)²)1 that, occurs in both the foliated and the massive forms. The foliated variety resembles talc in that it has a greasy feel, a pearly luster, perfect basal cleavage, and usually is white, although in some deposits apple green, gray, brown, russet, and nearly black specimens may be found. The massive deposits of pyrophyllite yield pearl gray to light tan aggregates, some of which are so friable that they may be crushed with the hands into a fine gritty powder. Frequently specimens of the massive variety are studded with crystals of radial structure. The mineral has a specific gravity of about 2.7 and a hardness of 1 on Mohs' scale.' The chemical composition of commercial pyrophyllite reflects the mineralogy of the deposits, which, according to Stuckey12 contain pyrophyllite and quartz, together with chloritoid, sericite, and a few other minerals of negligible importance. The latter, he says, ('are noticed in but small quantities to the extent they might occur as accessory constituents of an igneous rock or as products of regional metamorphism or weathering. . . . Quartz is abundant everywhere except in the very best grades of pyrophyllite." Analyses of specimens from several deposits are listed in Table 1, showing that the silica content varies from 57 to 73 per cent and the alumina from 22 to 33 per cent. Oxides of iron and the alkaline metals are collectively present, with one exception, to an extent of about 1 to 1.5 per cent. Sources At present, North Carolina is the only commercial source of pyrophyllite, although the mineral has been found in small quantities in many parts of the world. The North Carolina deposits are in the "Carolina Slate Belt," which traverses the center of the state in a southwesterly direction. This belt varies from 8 to 50 miles in width. Two major deposits of pyrophyllite lie along its eastern boundary, in what is known as the Deep

Jan 1, 1942

By M. F. Trice

Pyrophyllite is a hydrous aluminum silicate (A1²Si4O10(OH)²)1 that, occurs in both the foliated and the massive forms. The foliated variety resembles talc in that it has a greasy feel, a pearly luster, perfect basal cleavage, and usually is white, although in some deposits apple green, gray, brown, russet, and nearly black specimens may be found. The massive deposits of pyrophyllite yield pearl gray to light tan aggregates, some of which are so friable that they may be crushed with the hands into a fine gritty powder. Frequently specimens of the massive variety are studded with crystals of radial structure. The mineral has a specific gravity of about 2.7 and a hardness of 1 on Mohs' scale.' The chemical composition of commercial pyrophyllite reflects the mineralogy of the deposits, which, according to Stuckey12 contain pyrophyllite and quartz, together with chloritoid, sericite, and a few other minerals of negligible importance. The latter, he says, ('are noticed in but small quantities to the extent they might occur as accessory constituents of an igneous rock or as products of regional metamorphism or weathering. . . . Quartz is abundant everywhere except in the very best grades of pyrophyllite." Analyses of specimens from several deposits are listed in Table 1, showing that the silica content varies from 57 to 73 per cent and the alumina from 22 to 33 per cent. Oxides of iron and the alkaline metals are collectively present, with one exception, to an extent of about 1 to 1.5 per cent. Sources At present, North Carolina is the only commercial source of pyrophyllite, although the mineral has been found in small quantities in many parts of the world. The North Carolina deposits are in the "Carolina Slate Belt," which traverses the center of the state in a southwesterly direction. This belt varies from 8 to 50 miles in width. Two major deposits of pyrophyllite lie along its eastern boundary, in what is known as the Deep

Jan 1, 1942

Some years ago the open Hearth Committee of the Institute reached the conclusion that the reading of "set" papers tended to preclude the specific and detailed discussion of specialized problems of current interest to those operating steel plants. As an innovation the Committee distributed in advance of the meeting in May, 1927, a questionnaire containing a list of 27 topics involving operating problems. The subsequent discussion of the questions, participated in by 37 members, was a conspicuous success. Semiannual meetings have been held since; and at the conference of November, 1929, at Chicago, 131 men were present and the minutes comprised a book of 133 printed pages, thereby, indicating the growing value of the conference in the eyes of both the metallurgists themselves and the companies that employed them. With this example in mind, the Directors felt that definite advantages would accrue to a similar conference to be participated in by smelter officials and metallurgists engaged in the operation of copper reverberatory furnaces. The settlement of the Carson litigation, which for several years had virtually stopped public discussion of reverberatory practice, offered an opportune time for launching the scheme. Although the Conference may become largely self-financing in the future, some funds were regarded as necessary to conduct the first meeting. The members of the Rocky Mountain Income Committee, in view of the fact that copper smelting was essentially an activity of the Rocky Mountain area, recommended the project be, in effect, underwritten by the Fund, and the directors approved an appropriation for this purpose. Invitations were extended to high executives of the various-companies interested to send representatives to an initial meeting to be held at Salt Lake City, May 26-27. The response was enthusiastic. Twenty-three metallurgists representing 12 different plants were present to discuss the comprehensive-program relating to construction and operating phases of reverberatory smelting. It was understood that the record was not to be included in the regular publications of the Institute but that it would be prepared for private distribution among the participants and the officials of their companies. That the exchange of views and experience was no less instructive and stimulating than it was frank, full and informal is indicated by the following transcript of the minutes of the meeting.

Jan 1, 1930

By A. C. Veatch

Jan 1, 1921

By Henry M. Rowe

Professor Ruff's most illuminating paper' describing his extremely valuable investigation of the carbon-iron equilibrium diagram assigns definite temperatures to certain very important lines in the diagram, viz.: the eutectic temperature EB (Fig. 1) and the " near-eutectic " temperature E'B', but without indicating clearly enough the reasoning which warrants these assignments. These temperatures are of such primary importance that it is well to indicate the apparent gaps in the reasoning, in the hope that they may be filled in. In his diagram, Fig. 1, the point X and the liues B'D'lII represent the experimental results reached by Ruff and Goecke;a AB, AEB, and SE represent the liquidus, the solidus, and the solubility of the carbon in solid austenite in the absence of graphite according to Gutowsky,3 AB being also in accordance with Spiecker's data; S'E' the solubility of carbon in solid austenite in the presence of graphite according to Ruer and Iljin;5 GS the line A3 after Ooerens and Meyer; 6 and EBC the true eutectic line as inferred by Prof. Ruff from Gutowsky's data. B'D' is the carbon content found in cast-iron which had apparently saturated itself with carbon in the presence of the graphite of the enclosing graphite crucibles in which the determinations were made. From its straightiiess and its sharp inflection near 6.67 per cent. of carbon, the carbon content of

Jan 1, 1913

By R. M. Raymond

RECENTLY one of the Welsh coal companies, which has an excellent plant of up-to-date ma-chinery both on the surface and underground, operated under modern methods, sent one of its engi-neers to the United States to study actual operations in the mines. He visited several of the most important and best conducted collieries, went back, and reported that the greatest difference between operations in England and in the United States was. the closer con-tact between management and workmen. By manage-ment he meant management all the way through; close cooperation between office management, superintend-ents, foremen, shift-bosses, etc., and the workmen. A visit to some of the coal mines in that country by the writer made this fact rather impressive. The feel-ing on this side of the water that the methods in use in the coal mines in England are not up-to-date was found in many cases to be quite erroneous. Many mines, particularly those with very thin beds, in which profitable operations are doubtful under the best con-ditions, have necessarily had to adhere to old methods instead of making mechanical improvements. The Powell-Duffryn mines, in the center of the South Wales district, are certainly operating successfully, and have planned their business excellently. Sufficient areas of contiguous land have been leased for extended opera-tions. Mine plants are laid out in the valley, for work-ings on both sides, on a reasonable tonnage of 1500 to 3000 tons to each operation. The beds are from 30 to 48 in. thickness, and a 3-ft. seam is considered an ex-cellent thickness of coal; in fact, the miners prefer to work on the thinner beds rather than the thick ones, where they consider it more difficult to control the backs. This company is making use of its fine coal for produc-ing electric power, which is distributed to its own operations, and for use in the communities adjoining. For this purpose methods of cleaning the fine coal are being put into use. Compressed air is generated at the central power plant and is transmitted over long dis-tances to various mines in each valley. A byproduct coke plant uses more of the fine coal and gives further returns from non-commercial coal. The long-wall system applied in sections of limited size is popular in working the small seams, and me-chanical cutting is used, also handling either by shaking chutes or belt conveyors, or a combination of both. In some mines mechanical cutting is not necessary. The backs are so handled that in the softer or somewhat crushed seams hand cutting can be carried on effec-tively.

Jan 10, 1927

By Harry M. Mikami, Harold A. Heiligman

The term chromite is often used to cover all chrome ores and concentrates which are the designations actually employed by most industrial users and producers. Chromite is, of course, the predominant mineral in chrome ores which are aggregates of chromite and gangue minerals, most commonly magnesian silicates. Most chrome ores now used are petrographically chromitites which is a rock, rather than an individual mineral term. The title of this chapter, following past usage, is meant in the broad sense. Chromite is the only primary commercial source of chromium. This book is intended to deal only with nonmetallic minerals and rocks. Chromite uses are both metallic (ferroalloys) and nonmetallic (refractories and chemicals), but any discussion of mineralogy, geology, and mining is common for all types. A number of the major commercial ores are interchangeable, and their uses are determined by economic considerations. Mineralogy COMPOSITION [Chromite is a term embracing a wide range of chromium-bearing spinel*-group minerals the compositions of which can be expressed as (Mg,Fe2+)0.(Cr,AI,Fe3+ )203.t This can be further generalized to R2+O.R23+03 and the molecular RO: R,03 ratio is generally close to one. The exact composition may be arbitrarily expressed as a solid solution of six end-members, MgAI2O4, MgCr2O4, MgFe2O4 FeCr2O4, FeA12O4, and Fe2+.Fe23+04 with the proportions of each stated or plotted in the six-cornered prism of Johnston and Stevens61 or this scheme may be simplified to comprise only three endmembers making up a composition triangle, Fig 1. [ ] FIG 1-Triaxial composition diagram showing molecular compositions of chromites listed in Table 1. The RO.Fe2O3 corner includes Ti02 norms listed in the table. Note that the high-alumina chromites (1, 2, 3, 9), form a cluster well apart from the high-Cr2O3 chromites. There is a tendency for high-iron chromites to be higher in Fe2O3 + TiO2 but it is not a consistent or systematic relationship. The MgO/RO ratio must also be known to characterize the chromite chemically. Simplest and most convenient method is Thayer's' in which a chromite such as (Mg.65Fe.352+)O.(Cr.40Al.50Fe.103+)203 would be written as (Mge,) Cr eAlo. The molecular pro- portions of ferrous and ferric oxides can be seen at a glance as the divalent and trivalent oxides]

Jan 1, 1960

By E. Gybbon Spilsbury

It is not my purpose in this paper to describe all the different contrivances which have been devised, during the last quarter of a century, for the purpose of Iessening the expense of mining and tunnelling operations; I wish merely to call your attention to the crying want of the Western miners for some cheap and effective machine, capable of economizing on the heavy item of hand-drilling, and to enumerate a few of the latest improvements which have been made in machines of this class. This necessity for the introduction of some kind of labor-saving machinery in mining, especially in the West, begins to make itself felt more imperatively every day. No branch of industry has remained so conservative to the old customs and systems of working, as has mining; and yet no branch is so entirely dependent on economical working for a successful issue; and in very few is the proportion of cost of hand-labor to profits obtained so preponderantly heavy. Perhaps the chief reason for this seeming apathy towards progress in this direction arises from the fact that nearly all mining operations, especially in this country, are carried on in regions more or less remote from the great centres of civilization, thereby rendering the carriage and erection of machinery extremely difficult and expensive. Another reason, however, exists in the fact that a large number of men in charge of mining operations are greatly prejudiced against the introduction of machinery underground, from the idea that it cannot be made to adapt itself to the various positions and

ALABAMA Anniston.-Bretz, J. A. Carrington, F. G. Gerber, A. B. Klugh, B. G. Semple, R. A. Ashland.-Barton, .J. Bessemer.-Abbott, C. E'. Ball, T. L. Beaver, J. J. Ferguson, V. Salmon, H. S. Sehaber, C. F. Whatley, W. J.

Jan 1, 1923

By H. K. Livingston

THE first person to investigate intensively the vast field of surface phenomena and capillary effects was the eminent English scientist, Lord Rayleigh (1842-1919), who laid down most of the fundamentals of this subject. This work was greatly amplified by Irving Langmuir,1 who, in connection with research for the General Electric Co., spent 25 years on the study of the surface chemistry of films, finally receiving the Nobel Prize in Chemistry for 1932 in recognition of his work. At present, William Harkins,2 of the University of Chicago, is the world's foremost authority on surface-tension measurement and his independent work, when combined with that of Langmuir, resulted in the orientation con-cept of solubility and surface activity, which is now an important funda-mental in chemistry. The theory laid down by these men was first applied to practical considerations regarding petroleum reservoirs by F. E. Bartell,3 of the University of Michigan, in connection with an American Petroleum Institute research grant. The latest and most advanced application of Bartell's work is contained in an article published in 1935 by Allen Garrison,4 of Rice Institute, in which he relates Bartell's measurements to the ratio of oil to water produced by wells and shows the types of petroleum reservoirs where the effects studied by Bartell are significant. This article is intended as a minor extension of such work.

Jan 1, 1938

By Henry Mulryan

THE largest and purest known deposit of diatomite is being actively mined and processed 3 ½ miles south of Lompoc, Santa Barbara County, Calif., by the Johns-Manville Products Corporation. The workings FIG. 1-LOCATION OF DIATOMITE DEPOSIT AT LOMPOC. cover 4000 acres, the depth of economically recoverable diatomite being 1000 ft. (Fig. 1). Lompoc, a community of 2500 population, is situated in the Santa Ynez River Valley 10 miles inland from the Pacific Ocean. It is 44 miles

Jan 1, 1936