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Sec. 1. The membership of the Institute shall comprise six classes, namely: 1. Members; 2. Honorary Members; 3. Senior Members; 4. Associates; 5. Junior Members; 6. Rocky Mountain Members. All shall be equally entitled to the privileges of membership, excepting that no member of any class whom residence shall be outside of the United States of America, except those residing in Mexico and Canada, shall be entitled to vote. SEC. 2. Members: A person to be eligible for election or transfer into the claw of Member must be at least 27 years of age and must have had at least six years' employment in the practice of engineering, mining, geology, metallurgy, or chemistry, during at least three years of which he must have held positions of responsibility in one or more of these fields. This shall not apply to Rocky Mountain members.

Jan 1, 1939

By Barry S. Epstein

Financing the acquisition of a going coal mine operation has not had the exposure other finance-oriented projects have had. Therefore, C.I.T. feels that coal mining people and financial people should improve their understanding of the factors involved in this important type of acquisition. The discussion consists of two major subjects: analysis of the acquisition of the property, and sources and terms of funding the acquisition. Source and Terms of Funding There is a need to keep the competent medium-sized independent operator in the coal business, especially in these times of energy shortage. The creation of a resale market for coal mines encourages new investment in the coal mining business by medium-sized operators and their financial backers. Who provides debt and equity financing to acquire going coal mine operations and on what terms?

Jan 9, 1975

INTO their great Pacific Northwest counting house went the members of the Industrial Minerals Division recently, to count their blessings amidst the scenic grandeur and mineral wealth of the State of Washington. From their vantage point in Seattle, those who attended the IMD's fourth Pacific Northwest meeting turned their sights to the South and Southeast, scanned Montana, Idaho, Oregon and Utah, and predicted a very healthy economic future for their region. The praises of Idaho's booming phosphate industry were sung by Earl W. Murphy, secretary of that State's Chamber of Commerce. He said the establishment of Fort Hall, on the banks of the Snake River near Pocatello, first turned the eyes of the world toward what is now the center of the greatest known deposits of phosphate rock-the section adjacent to the common corners of Idaho, Wyoming and Utah. With the founding of Fort Hall, Mr. Murphy said, historians will also rank the construction of the first electric furnaces for the production of elemental phosphorous as equally significant in the commercial history of the West. Those furnaces were installed only last year by the Westvaco Chemical Div. of the Food Machinery & Chemical Corp. at Pocatello, at a cost of $8 million.

Jan 7, 1950

By Duncan MacVichie

THE iron fields described here are located in the Iron Springs and Pinto Mining districts, Iron County, Utah. This region is in southwestern Utah, about 260 miles south from Salt Lake City, and is reached by the Los Angeles & Salt Lake railroad of the Union Pacific system. The iron fields lie at an elevation of 5500 to 7500 ft. above sea level, and are essentially desert in character. They are covered with a light growth of sage brush, piñon pine, and scattered cedar. Weather conditions are unusually favorable for all-year mining operations, the winters being mild with little or no snow; and the summers not excessively hot, the temperature rarely rising to 100° during the day, while the nights are invariably cool. The iron-ore bearing area extends from the Iron Springs district to the Iron Mountain mining district, being approximately 25 miles long in a northeast-southwest direction, and from 1 to 3 miles wide in a northwest-southeast direction. In the Iron Springs and Pinto mining districts, the ore occurs at various points around three sides of Granite Mountain and Iron Mountain. This is readily understood by reference to Figs. 1-4. These mountains are composed of andesite, which has been forced up through the surrounding sedimentary formation, in the form of laccoliths. An extensive report on the geology of these districts was made by Leith and Harder,1 who state: The three dominating geological features of the district are three large andesite laccoliths which constitute the Three Peaks, Granite Mountain, and Iron Mountain; lying in a northeast-southwest line across the area in question. Three unconformable sedimentary series, aggregating 4000 ft. in thickness, outcrop in successive rings around these laccoliths, dipping outward asymmetrically, very steeply at the contact, less steeply further away. Still farther from the laccoliths, lava-flows 2000 ft. thick rest in nearly horizontal attitudes on the tilted sedimentary rocks. These general relations are modified by faulting. All of the rock formations of the district are more or less covered on the middle and lower slopes by unconsolidated and partly consolidated erosion debris, both aqueous and subaerial, which spreads out on the lower ground to make the deserts.

Jan 7, 1925

By L. E. Porter, H. P. Hassel

The state of California produced 310,-996,696 bbl. of oil and about 415,832,000 M cu. ft. of gas in 1944. Such oil production represented 18.5 per cent of the nation's production, as compared with 19 per cent in 1943 ,The tremendous demand placed upon the California fields is indicated by the monthly production in 1944, as follows: Month Barrels per Day Jan................... 809,262 Feb.................. 820,712 Mar.................. 824,592 .4pr ................. 829,973 May.................. 832,068 June.................. 846,038 July.................. 849,231 Aug.................. 858,932 Sept.................. 885,823 Oct................... 877,667 Nov.................. 876,613 Dec.................. 883,847 In all, 2100 wells in proved areas and 269 wildcats were drilled in California during the year 1944. At the end of the year, approximately 270 wells were drilling in the state, as compared with 156 wells at the same time in the preceding year. Nine new fields or new zone discoveries were made during the year, which, according to best estimates, will contribute some 77,000,000 bbl. of new reserves; in addition, the extensions of old fields will increase the new reserves about 165,000,000 bbl., or a combined total, through dis- coveries of new fields, zones, and extensions, of 242,000,000 bbl., offsetting to the extent of about 78 per cent the total oil produced during the year. Geographically, the reserves from these new field and zone discoveries and extensions are distributed as follows: Per Cent San Joaquin Valley........ 72 Coast Area............... 24 Los Angeles Basin Fields. . . 4 100 The state's reserves of crude oil at the end of the year have been estimated to be distributed as follows: The outstanding development project for the year was that of the United States Navy in the Naval Petroleum Reserve No. I, Elk Hills field. During the year, 115 wells were completed in this field, and at the close of the year an average of 19 strings of tools were drilling. This program is being jointly conducted by the Standard Oil Co. of California with the Navy and is designed to increase the production of Naval Petroleum Reserves from approxi-

Jan 1, 1945

By P. S. Roller

P. S. ROLLER,* College Park, Md.-The author introduces the idea of a grind limit, or lower size limit of the particles formed directly by grinding, and this is stipulated to be 0.70 micron. I wonder where all the particles come from that lie between the resolving power of the microscope and 0.7 micron, which are seen under a microscope in examining a sample of grind? There is also introduced the idea of excess fines; this is all right in itself but the author's quantitative definition seems to be virtually impossible to justify, and, moreover, is obscure. Just why E, the excess fines, should be defined as the distance between an F line and a [?] line is hard to follow, and just where the distance should be measured does not appear to be stated, as it should be since the F and [?] lines intersect and the distance between will depend upon where that distance is measured. The basis of the presentation is the relation of log weight against log size that was "discovered" by Schuhmann. While this relation is implied to fit, the only evidence that I can see is a slightly irregular line in Fig. I between 2 per cent and 18 per cent by weight and then a precipitous drop at 18 per cent away from any sort of straight line. Some of the conclusions are rather startling. It is stated that E, the excess fines, remains constant for all the comminution products of any particular material, except that it may decrease for some coarse crusher products. No reason is given for this assertion. One would, on the contrary, expect that excess fines, if such a concept is permissible, would generally vary with different conditions instead of being constant. Again, "as much net energy is required to reduce a ton of quartz to particles of the grind-limit diameter (namely, of course, 0.7 micron) by grinding as is required to melt the quartz," This would require many data to prove, but no proof is given; any considera¬tion would reveal the impossibility of such a result. Still further, ore samples "ground to widely different sizes, and with different circulating loads and different size distributions or product, show the same production of new surface area per revolution of the mill, when this grind limit is used." This statement is confuted by ordinary experience, which teaches that grinding efficiency varies generally with the condition of material. For example, the cushioning effect of fines is widely accepted, while the inefficiency of a ball mill when the feed is too coarse is also well known. R. SCHUHMANN, JR.,* Cambridge, Mass.¬Contrary to Mr. Bond's stand, there is a great deal of miscellaneous experimental evidence that comminution does not stop at around 0.7 micron, nor does it cease consuming energy at that point. Comminution is in fact recognized as an important method of producing colloids.5 Mechanical comminution methods were used by von Weimarn6 to produce colloidal dispersions of a variety of solids, including the minerals chalcocite, galena, hematite, stibnite. Utzino7 gives average particle sizes ranging from 0.02 to 0.09 micron for colloids produced by mechanical comminution of several crystalline solids. Andreasen and Berg8 have ground

Jan 1, 1941

By Sherwin F. Kelly

THE joint meetings of the Mining Geology Committee and the Society of Economic Geologists proved to be deservedly popular, and the interesting papers drew an attendance which strained the capacity of one of the large meeting rooms.. As might be expected these days when even the Supreme Court can't keep away from the subject of gold, the discussions opened on Thursday morning with several papers devoted to questions of structural and mineralogical relationships of the deposits of this metal. The presentation of Ira B. Joralemon's paper, "Veins and Faults in the Bralorne Mine," by Reno Sales, elicited considerable discussion on the relation of mariposite to gold, and the situation of the gold deposits with respect -to the Coast Range batholith. H. V. Warren stated that lie had observed mariposite always to be associated with gold in this region, but that gold was not always associated with mariposite. He pointed out that there is a series of veins on the west side of the batholith with a different mineralogy that, because of their richness but small size could quite easily make good, small mines. John A. Dresser concurred in this, and said lie thought this region was one of great promise for the mining geologist. He also reported having found mariposite associated with gold values below commercial limits, in the Appalachian regions.

Jan 1, 1935

By John Chipman

RECENT developments in iron alloys containing nitrogen have indi-cated that this element may exert a considerable influence on the proper-ties of the metal. This influence is not always in an undesirable direction and the indications are that nitrogen should be regarded as an alloying element, the amount of which should be subject to control, rather than as an inherently deleterious impurity. In controlling this element in liquid iron to the best advantage, it is necessary to have a reliable background of fundamental data pertaining to solubilities, rates of solution and chemical reactions of nitrogen in liquid iron. Obviously, the first step in such an investigation is the determination of the solubility of nitrogen in pure iron, and this has been the object of the experiments described in this paper. The solubility of nitrogen in solid iron has been measured by Jurich,1 Sieverts,2 Martin,3 and Iwasé4 and the agreement among the first three inspires confidence in their results. No accurate determinations of its solubility in liquid iron have been recorded though several investigators have obtained approximate results. Strauss5 was able to introduce 0.03 to 0.04 per cent nitrogen into steel by the action of either ammonia or nitrogen on the liquid metal. This was accomplished by Eilender and

Jan 1, 1935

By G. I. Madden, L. H. Van Vlack

WhEN basic refractories which contain peri-clase, MgO, are used in steel furnaces, they are altered by iron oxide to form magnesiowiistite, (Mg,Fe)O, and an iron-rich magnesioferrite, (Mg,Fe)Fe2O4. Silica, which is usually present, produces a silicate liquid that surrounds the solid phases. The individual crystalline grains of the above two solid phases grow at elevated temperatures. Previous papersL" showed that, if either periclase or magnesiowiistite is present as the only solid phase, its grain size increases in proportion to temperature and in proportion to the square root of time; the growth rate is reduced slightly if the amount of silicate liquid is increased. Similar results have been observed for iron-rich magnesioferrite.3 To determine the effect of the presence of two solid phases on the rate of grain growth, micro-structural studies have been made on samples containing both magnesiowustite and magnesioferrite. The experimental procedure was the same as that followed in the previous studies of this type.'12 Briefly, this included determination of compositions from the available phase relationships4 that would produce the two phases of interest at the firing temperature and using reagent-grade raw materials to prepare mixtures of these compositions. The mixtures were pressed into pellet-size samples and then fired at the desired time and temperature. The samples were water-quenched to preserve the microstructure present at the firing temperature. Standard reflected-light metallographic techniques were used for sample examination and sample analysis. Grain sizes were determined by measuring the mean diameter of a number of randomly selected grains in a two-dimensional microsection. A large cross section of the sample was covered to prevent biased data resulting from such effects as localized differences in the radius of curvature of the crystal grains. Examination indicates that grain growth is restricted when more than one solid phase is present. This is illustrated in Fig. 1 for: (a) magnesiowustite plus a silicate liquid; (b) magnesioferrite plus a silicate liquid; and (c) magnesiowiistite and magnesioferrite plus a silicate liquid. Fig. 2 plots the

Jan 1, 1964

By John L. Watson

A conceptual model (MAGSEP) is described to simulate the beneficiation characteristics of a drum magnetic separator in terms of the probability of an individual grain being recovered in the magnetic concentrate. This probability is determined as a function of particle magnetic composition and magnetic field strength and is modified by particle size and the separator operating conditions. The model predicts the size, magnetic grade and distributions of magnetic and gangue minerals in the concentrate and tailings produced by the drum separator. The configuration of the magnetic concentration circuit may be altered to permit single or double drum units in parallel or series operation. The characteristics of the feed material, in terms of a magnetic parameter, are essential in permitting the determination of individual grain recovery probabilities upon which the model is based. Thus the model requires input data relating to the distribution of composite grains in terms of magnetic grade and particle size. To illustrate the use of the conceptual model an example is given for the beneficiation of New Zealand iron sands.

Jan 1, 1984

By Albert F. J. Bordeaux

Discussion of the paper of Albert F. J. Bordeaux (Bi-Monthly Bulletin, No. 23, September, 190S, pp. 629 to 640). A. H. BROMLY, Zihuatanejo, Guerrero, Mexico (communication to the Secretary*) :-The following criticism of what "is offered as a summary which may be found useful by mining engineers," is not dictated by any captious spirit, but in the interest of historical and scientific accuracy. The States of Queretaro and Oaxaca have produced sufficient silver to warrant more extended notice. Referring to Pachuca, State of Hidalgo, the somewhat loose and. inexact statement is made that "the ore-deposit is an andesite, intermixed with quartz-veins, rich from the surface." A better description would be,-the ore-deposits consist of quartz-veins in andesite. It is notable that many of the rich shoots worked in recent days did not come to surface. In consequence, Pachuca, is often quoted by the ill-informed as a camp in which values improve with depth, the truth being that the veins carry shoots, or clavos, some of which were exposed at surface and some not. The name of " electric plow," applied to the mechanical stirrer of recent use, is certainly not to be recommended. The stirrer, or agitator, consists essentially of a traversing gang-plow, operated by power through shafting, drums, and wire-rope. The fact that in certain plants the motive-power used is electricity does not make it an electric plow. Such a name suggests a machine of which the motor is an essential and integral part; which is not so in this case. A lathe in a factory driven by water-power is not called a hydraulic lathe. My experience agrees with Dr. Raymond's note as to azulaque, which in sortie districts is also applied to blue copper carbonate. The El Oro, Esperanza, and Mexico mines should be allocated to the State of Mexico; the Dos Estrellas being in Michoacan, as stated. The El Oro quartz certainly does not appeal to me

May 1, 1909

By M. R. Hatfield, F. J. Vosburgh

In a recent article, it was shown that in the blast furnaces in Germany that are lined with carbon blocks no cooling plates are used, and that shower cooling is employed on the hearth and bosh sections. While one of the authors was in Germany he was told that one furnace was being operated without even the shower cooling on the bosh section, though the hearth section was shower-cooled. In discussion of this interesting situation with a number of blast-furnace operators in this country, it was made clearly and promptly evident that shower cooling was very unpopular, probably because of its messiness and its ineffectiveness. Both of the causes for the dislike of shower coolings are reasonable ones. Shower cooling can be and frequently is messy, but the present cooling of blast furnaces leaves much to be desired on that score. Shower cooling is ineffective as compared with plate cooling, so far as its usefulness in keeping the bricks cool enough not to melt or fall to pieces is concerned. However, the introduction of carbon linings changes the situation. No one is concerned with keeping a carbon lining cool, for no temperature in the blast furnace has any effect on carbon, which is just as stable at 3000°F. as it is at 70°F. The only concern is for the shell—to keep it cool enough for safety and comfort— and for that shower cooling is sufficient. Of course, with only the shell to cool, instead of the shell plus all the refractory material, much less water would be required, and the necessity for constant attention to the flow would be lessened, as the hundreds of inlets and outlets would be eliminated. Probably half of the water used in cooling a blast furnace is used for cooling the shaft and tuyeres and the remainder for the bosh and hearth sections. However, in view of the dislike of shower cooling in the United States, and particularly because at least one German blast furnace is operated with no cooling of the bosh section, thought was given to the possibility that a carbon-lined blast furnace might be operated without any cooling of the entire carbon-lined portion. For that reason a series of experiments was performed to determine what might be the temperature of the shell of a blast furnace protected by a carbon lining and operated under varying conditions up to a maximum inside temperature of 3000°F. Experimental Procedure A schematic diagram of the experimental setup is shown in Fig. I and a photograph of the entire assembly in Fig. 2. The heating element was a a tubc nominally 25/8 in. 0.d. by 2 in. i.d. by 30 in., used as a resistor. Power was furnished by a I5-kva. transformer operating

Jan 1, 1942

By M. R. Hatfield, F. J. Vosburgh

In a recent article, it was shown that in the blast furnaces in Germany that are lined with carbon blocks no cooling plates are used, and that shower cooling is employed on the hearth and bosh sections. While one of the authors was in Germany he was told that one furnace was being operated without even the shower cooling on the bosh section, though the hearth section was shower-cooled. In discussion of this interesting situation with a number of blast-furnace operators in this country, it was made clearly and promptly evident that shower cooling was very unpopular, probably because of its messiness and its ineffectiveness. Both of the causes for the dislike of shower coolings are reasonable ones. Shower cooling can be and frequently is messy, but the present cooling of blast furnaces leaves much to be desired on that score. Shower cooling is ineffective as compared with plate cooling, so far as its usefulness in keeping the bricks cool enough not to melt or fall to pieces is concerned. However, the introduction of carbon linings changes the situation. No one is concerned with keeping a carbon lining cool, for no temperature in the blast furnace has any effect on carbon, which is just as stable at 3000°F. as it is at 70°F. The only concern is for the shell—to keep it cool enough for safety and comfort— and for that shower cooling is sufficient. Of course, with only the shell to cool, instead of the shell plus all the refractory material, much less water would be required, and the necessity for constant attention to the flow would be lessened, as the hundreds of inlets and outlets would be eliminated. Probably half of the water used in cooling a blast furnace is used for cooling the shaft and tuyeres and the remainder for the bosh and hearth sections. However, in view of the dislike of shower cooling in the United States, and particularly because at least one German blast furnace is operated with no cooling of the bosh section, thought was given to the possibility that a carbon-lined blast furnace might be operated without any cooling of the entire carbon-lined portion. For that reason a series of experiments was performed to determine what might be the temperature of the shell of a blast furnace protected by a carbon lining and operated under varying conditions up to a maximum inside temperature of 3000°F. Experimental Procedure A schematic diagram of the experimental setup is shown in Fig. I and a photograph of the entire assembly in Fig. 2. The heating element was a a tubc nominally 25/8 in. 0.d. by 2 in. i.d. by 30 in., used as a resistor. Power was furnished by a I5-kva. transformer operating

Jan 1, 1942

By P. S. Rudman

The allotropic volume changes of the ,metallic elements are reviezoed with the conclusion that in general atomic volume is conserved to better than 1 pct in such transformations. A table of the atomic volumes of the metallic elements is given and its use in considering the size factor in alloys is discussed. The importance of the concept of atomic-size factor, due to Hume-Rothery and coworkers,' is firmly established. Most attempts at quantitative formulations of this concept have employed the atomic radius (half some interatomic distance) as the measure of size and innumerable tables of such radii exist. This is probably, however, an unfortunate choice of parameter. Firstly, discussion in terms of interatomic distances requires a knowledge of the crystal structure. While this is known, except for a few cases, for the elemental structures, there are still many undetermined alloy structures. Secondly, except for the simpler structures, face-centered cubic (Al),* body-centered cubic (A2),* and hexagonal-close-packed (A3).* with ideal axial ratio, there is no unique in- teratomic distance, an m y decision must be made as to which distance, or which average of the distances, should be used. However, the most important point is that for metals the dominant bonding parameter can generally be expected to be atomic volume and not interatomic distance. This is perhaps most explicitly stated in the Wigner-Seitz cellular method.' In this approximation, cellular polyhedra of atomic volume v are replaced by spheres of radius Y,: 4/3 ?rs3 = v. That is, there is no reference to the interatomic distances. If atomic volume is in fact the dominant parameter, then in allotropic transformations we might expect to find atomic volume approximately conserved. For example, in the A1 ? A2 transformation we would thus have

Jan 1, 1965

By A. Hamilton Garner

The occurrence of oil seepages in Venezuela has been known since the early days of Spanish occupation. It was not until 1912, however, that any serious exploration work was undertaken. In that year, the Caribbean Petroleum Co., then a subsidiary of the General Asphalt Co., employed a large staff of geologists to make a systematic survey of large areas in eastern and western Venezuela, selecting the most desirable localities out of the immense area covered by the Valladares concession. This preliminary work was completed in the fall of 1913, and in February, 1914, the company completed its first commercial well at Mene Grande. Development work has progressed slowly, for various reasons, but petroleum in quantity has been encountered in nine widely separated localities. The Mene Grande field has been put on a producing basis and approximately 4,000,000 bbl. of oil is being shipped annually. Increasing quantities of oil are now being drawn from El Mene and La Rosa. In the light of these developments, the world's need for oil reserves, and the proximity of Venezuela to the United States, American capital is being attracted more and more to Venezuela. Although considerable careful geological work has been done in Venezuela by the various oil companies now operating, most of the data is buried in the company files, and the published literature has been extremely meager. The most valuable contribution to date has been a map and report by Jahn, which, as it was printed in Spanish, is not generally available to the American oil public. Venezuela, located in the northwestern part of South America on the Caribbean Sea, lies between l° and 12° north latitude. Its principal

Jan 1, 1925

By Edward Keller

In order to conduct intelligently the sampling of copper of various forms and grades, solid or in molten furnace-charges, a knowledge of this subject is essential. Yet figures and tests have been persistently withheld from publication, and the books at our command give us little or no information in this regard. This gap in our copper-literature has led to a series of experiments, the results of which are given below. Nearly all gold- and silver-bearing copper, destined for shipment, is cast into the form of bars or pigs. For the sampler, the question arises, Does copper, so cast, remain homogeneous ? If it does, sampling should present no difficulties; but, from experience, we know that this is not the case, and we are thus led to study the behavior of the precious metals arid impurities in copper when the latter changes from the molten to the solid state. For the purpose of the experiments here described, all available grades of copper were selected, and all of them mere subjected to the same conditions, an important requisite for proper comparison. The molten copper obtained directly from reverberatory- and blast-furnaces was cast in a cast-iron mould, the sides and bottom of which were 1 inch thick, and would, therefore, give the copper a fair length of time to chill. The inside dimensions of the mould, and, consequently, of the block of copper obtained, were: length, 10 inches; width, 9 inches; and depth, 5 inches. Fig. 1 illustrates the method employed to obtain samples from these blocks. A was cut away, and the face so produced BALTIMORE COPPER WORKS,

Jan 1, 1898

By K. C. Li

ARSENIC and antimony are always grouped together by chemists, since they are both members of group V of the periodic table of elements and exhibit a general similarity in the formation of compounds. Metallurgists generally think of them as less closely related because they do not have similar uses. In metallurgical operations, especially lead and copper smelting, arsenic tends to go off as a vapor phase and collect as fume in the flues, while antimony tends to remain with the bullion. Broadly speaking, the frequency of occurrence, practical utility and the effects on associated metals of arsenic and antimony are such that the metallurgist is inclined to think of arsenic as a troublesome impurity in ores, but of antimony as a valuable constituent that is recovered either as a byproduct or through the metallurgical treatment of antimony ores. Estimating the world production of arsenic as about 40,000 tons annually, probably not more than about 200 tons yearly is produced and used in metallic form, whereas one half of the approximately 40,000 tons of antimony produced annually is metallic. ARSENIC The modern uses of arsenic differ little from ancient ones. Though it has been known from early times, its poisonous quality is almost the only one that yet finds extensive use. The shift in the past century from its utilization in poisoning people to the poisoning of insects, beginning in 1860, has not only led to a considerable increase in

Jan 1, 1953

By F. O. Willhofft

The symposium on mine safety held in connection with the annual meeting of the Institute three years ago, it. was pointed out that "at present no convenient, reliable, accurate means for determining the gas content of mine air is available, for use by the ordinary mine man." In a letter addressed to Coal Age and published on Feb. 25, 1925, Thomas T. Read, then Director of the Safety Service of the Bureau of Mines, stated: "It is to be hoped that sometime in the near future some-one will invent a reliable methane indicator that is con-venient to, use and will permit the keeping of all flames of every character out of bituminous mines, through doing away with the safety lamp." The Martienssen methane detector, which has re-cently received the official approval of the Bureau of Mines, is intended to. meet the demand for such an in-strument as expressed at that meeting and on many other occasions. The characteristics which qualify it for the task are the following: (1) simplicity; (2) small bulk and light weight; (3) ruggedness; (4) accuracy sufficient for the requirements; (5) safety; and (6) dependability. The principle on which the working of the instrument is based may best be explained by giving a brief out-line of the various stages of development through which the inventor, Professor Martienssen of the University of Kiel, Germany, advanced to the final solution of the problem which he had undertaken to solve.

Jan 2, 1928

By R. A. Salathiel

A new synthetic material has been developed which is highly effective in treating drilling muds to reduce filtration rate. The material is the soluble salt of a very high molecular weight condensation product of sulfonated phenol and formaldehyde (SPIF). Laboratory tests show that SPIF is effective in muds of all salinities varying from fresh water to saturated salt water. Alkaline materials. such as soda ash or caustic and quebracho, may be used in combination with SPIF to advantage, and are essential in muds containing saturated salt water. In a field test where the water used in the mud had a salinity of about one-half that of sea water, SPIF in combination with caustic and quebracho made a very satisfactory mud. SPIF does not ferment. but due probably to additional polymerization a slight decrease in effectiveness is found when it is subjected to high PH and high temperature for a long time. INTRODUCTION Drilling mud is essential in rotary drilling. The influence of variations in the different properties of a mud on its ability to perform the various functions in drilling of wells is thoroughly understood in some cases and poorly understood in others. For instance, the function of mud density in restraining high pressure fluids is simple and well known. On the other hand. while the value of low filtration is widely recognized, it is seldom possible to determine precisely what filtration rate is required for the mud to perform its functions properly. Filtration rate is important because it influences the ease of moving tools in or out of the hole. Filtration rate also affects the stability of the bore hole walls, which are subject to softening and degradation by aqueous filtrate. Difficulties in rotary drilling are often avoided by using low-filtration muds. Treatment of fresh-water muds to provide moderately low filtration rates usually consists of adding chemicals to improve the dispersion of the clays. To provide very low filtration rates, organic colloidal materials are added. Among the materials hat are used in this way are starch, natural gums, and altered celluloses. In muds that contain large amounts of salt or calcium or magnesium ions, the clays are coagulated and, as a consequence, the filtration rate is undesirably high. In such muds organic colloids are of great importance. LIMITATIONS OF PRESENT FILTRATION ADDITIVES Starch and water-soluble gums are widely used as filtration control agents. Starch is the most important material of this kind being used. It has the advantage of relatively low cost. It is effective in promoting low filtration rates, not only in fresh water muds, but also in muds containing large amounts of salts. However, both starch and natural gums are subject to fermentation and must be preserved from damage caused by microbiologic attack. Also, both starch and natural gums tend to increase the mud viscosity undesirably. Furthermore, the quantity of material required may be quite large. This is especially true when substantial amounts of salts are present. In such a case small addition* of starch may increase rather than reduce the filtration rate of the mud. Carboxy-methyl-cellulose, a chemically altered form of cellulose, has some advantages over starch. It is effective in smaller concentrations and does not increase the viscosity as much as

Jan 1, 1952

Addicks, L Ambler, J O Anderson, F B Armstrong, T Allen, L M, Jr Arnold, C E Adams, C E Adams, R E Anderson, A J Booth, E L Bernhardt, D I Boyd, W S Browning, W C Blake, D E Black, T B Bergman, Julius Bowen, H P Beckett, P G Blickensdefer, F C Bond, Josiah Butler, P P Bondlas. Y

Jan 1, 1923