Search Documents

By H. W. Ahrenholz

Seven weeks of 1971 were devoted to a nationwide coal walkout resulting in lost production of some 70 million tons and leaving 1971 coal production at about 550 million tons. Compounding the problem, consumption of coal in 1971 by electric utilities rose by about 5% to 336 million tons. In the mean- time, numerous contracts were awarded for coal R&D including $24.8 million given by the Office of Coal Research to Bituminous Coal Research for the construction of a coal-to-gas pilot plant using the BIGAS process. Exports declined mainly due to Japan's decrease in steel production and to that country's increase in coal imports from Canada and Australia. The advances in equipment design and mining procedures made 1971 a noteworthy year. Introduction of the variable pitch I dipper, the trend toward wheeled vehicles, the greater use of scrapers in reclamation and battery-operated vehicles and oscil-mining, and the increased activity in the areas of ventilation and dust control were given widespread approval. There were also strides made in computerization, longwall mining, roof bolting, rock dusting, mine haulage and methane detection.

Jan 2, 1972

By Noel Stearn

OF THE many instruments devised for the measurement of magnetic anomalies, the ordinary dip needle, by virtue of its superior simplicity of construction, facility of manipulation, and definiteness of interpretation, seems to merit serious attention as the instrument most readily applicable to the detection of magnetic anomalies of the higher order of magnitude. , In spite of the fact that it has been used for many years for the discovery of iron ore in Europe and in the Lake Superior region of America, its capabilities as a geological instrument have not yet been thoroughly plumbed. The Wisconsin Geological Survey, under Dr. W. 0. Hotchkiss, E. F. Bean, and H. R. Aldrich, has been most thorough in developing the technique of the instrument, and the results it has obtained have aroused a general interest in a more widespread use of geomagnetics as an exploration method and the dip needle as a geological instrument. The simplicity of the instrument is an especial advantage, as it can be used by anyone, regardless of his technical training; but to insure useful results not only is a knowledge of the background of geomagnetics necessary but also an understanding of the principles of the instrument itself.

Jan 1, 1928

By A. P. Coldren, V. Biss

SINCE the r ? a transformation rates of many carbon-free ferrous alloys and low-carbon alloy steels are relatively fast, conventional equipment is not suitable for the dilatometric determination of continuous cooling transformation diagrams. On the other hand, a method based on metallographic analysis of quenched specimens would not be practicable because the various products of shear-dominated transformation are essentially indistinguishable in low-carbon iron-base alloys. Both problems may be avoided by a thermal analysis method employing gas quenching of small specimens austenitized in vacuo. The laboratory equipment employed in the present study consisted of a Tektronix Type 564 Storage Screen Oscilloscope and a Kinney high-vacuum evaporator, modified as shown in Fig. 1, to permit heating a small specimen and cooling it slowly by programmed cooling or rapidly (up to about 8000°F per sec) by a controlled quench with helium gas. The oscilloscope records the electromotive force of a 40-gage (0.003-in.-diam) Chromel-Alumel thermocouple in the specimen during cooling. The temperature at which the cooling curve begins to show the influence of the heat produced by the phase change in the specimen was arbitrarily taken as the transformation-start temperature.*

Jan 1, 1970

By J. J. K. Daemen, C. Fairhurst

Introduction The stress field around a supported tunnel can be considered as being composed of: i) the virgin (pre-mining) stress in the rock ii) the (elastic) change in this stress field caused by creating the opening iii) the (time-dependent ) change in the stress field produced by (i) and (ii) as a section of the rock breaks up iv) the (time-dependent) influence of the stress build-up in the support. Several authors have examined the conditions necessary to produce static equilibrium between the support, the rock, and the regional (in-situ) stress field. The analysis used by Labasse (1) is typical. Consider a circular tunnel radius R in a hydrostatic stress field (P), and a radial pressure pi exerted by the support. According to Labasse, the radius ‘b’ to which the rock will break* for a given support pressure, pi, can be calculated from: - the equilibrium equation: [ ] As a zone of broken rock develops around the opening, the stress circle for a point on the elastic-broken rock boundary moves to the right in the Mohr diagram until the radial stress in the broken zone s equal to the radial stress in the elastic zone.

Jan 1, 1971

By R. Laird Auchmuty

FOREWORD THE A. I. M. E. Subcommittee on Bituminous Mining has been trying for several years to secure the information that was collected by the Marquette Cement Manufacturing Co. on the subsidence of its property caused by mining coal beneath it. The Marquette company was willing to have these data used, but it was impossible to obtain them because the records had been filed away. About two years ago these records became available and the engineering data presented herewith were compiled from them by R. L. Auchmuty, assisted by L. E. Young, who was connected with the collection of the information. On account of the cost, it is impossible to reproduce all of the data here, although the original information is on file with the records of the Committee on Ground Movement and Subsidence. The accompanying charts show representative and average data and give only the engineering information with enough description to tell how it was obtained. It is hoped that all of those connected with the original case will participate in the discussion that this will bring forth. HOWARD N. EAVENSON, Chairman, Subcommittee on Bituminous Coal Mining.

Jan 1, 1931

By E. C. Robertson

Observations of faults in mines, at outcrops, and in the laboratory lead to the conclusion that the displacement d of a fault increases irregularly but monotonically with the thickness t of its associated fault gouge and breccia, not including adjacent undisplaced jointed rock. The general trend of data points has a slope d/t of about 100. (The correlation coefficient of a logarithmic regression line is r = 0.94.) The rather wide scatter of the points can be accounted for by inaccuracies in measurement of d and t, and by variation in the conditions at faulting of confining pressure, rock type, water pressure, and deformation history. Limestone is an exception to the relation. Until the data can be corrected and refined, the relation should be used only qualitatively for estimating displacement of ore bodies in mines. The suggested relation is based on observations of 48 steeply- dipping normal and reverse faults and nine small flat-dipping thrust faults, with displacement less than 5 km (3 miles). It does not apply to large strike-slip and low-angle overthrust faults because their large displacements are poorly determined and their breccia thicknesses are widely variable.

Jan 1, 1984

By Robert I. Kingman

SUFFICIENT testing has been performed with the Dutch State Mines Cyclone for thickening and desliming flotation feed at the concentrator of the National Lead Co., Tahawus, N. Y., to prove its application for this work. It is the purpose of this article to present some of the test results, operational details and advantages of cyclone thickening and classification. The metallurgy of the mill operation was described by Frank R. Milliken, assistant manager of the titanium division.l The present flowsheet for the recovery of ilmenite consists in grinding the crushing plant product in four open-end rod mills in closed circuit with mechanically vibrating screens to approximately -20 mesh. The screen undersize is treated in Crockett magnetic separators which produce three products: magnetic concentrate, nonmagnetic tailing containing ilmenite and gangue, and a Crockett slime overflow. The non- magnetic tailing is classified into eight sizer spigots products and a classifier overflow. The spigot sand products are tabled separately to produce a rough ilmenite concentrate, a middling product and a tailing. The table middlings are returned to Crockett feed. The table concentrate is dewatered and dried and further concentrated on Wetherill magnetic separators to produce the finished ilmenite concentrate.

Jan 8, 1950

By James B. Cathcart

The potash mine of the International Minerals and Chemical Corp. is about 18 miles east of Carlsbad, New Mexico, in sec 1 and 12, T 22 S, R 29 E, N.M.P.M. Potash is produced from two zones in the Salado formation of late Permian age. The lower zone, consisting of a mixture of sylvite (KCl) and halite (NaCl), lies at a depth of about 900 ft, and the upper zone, in which the principal potassium mineral is langbeinite (K2S04.2MgS0d), lies at a depth of about 800 ft. Because of the plastic nature of the material, fractures in the Salado formation are extremely rare and have been noted only on the 800 ft level of the International mine. The open fracture described below is almost unique. Only one other open fracture has been noted, and it was on a working face in the same general area as the one described, but was destroyed before the writer had a chance to examine it. According to J. E. Tong, foreman on the 800 level, this fracture was similar to, but smaller than, the one herein described.

Jan 1, 1949

By AIME AIME

THE Committee on Elimination of Waste in industry came into existence from a speech in Washington by Mr. ,Hoover, in November, in which, he said: It is primary to mention the three-phase waste in production: first, from intermittent employment; second, from unemployment that arises in shifting of industrial currents; and third; from strikes and lockouts. Beyond this elimination of waste there is another field of progress in the adoption of measures for positive improvement in production.

Jan 1, 1921

By Henry Howe

W. E. RUDER, Schenectady, N. Y.-In 1913 I presented a paper before this society on Grain Growth, and at that time it seemed to me that the only explanation for grain growth was that of critical strain. I do not think I published the photographs at the time, but I made some experiments on the effect of stretching sheets of metal. This allowed for fairly accurate determinations of the amount of cold deformation, At the time I worked-with silicon steel because one could see the change in grain growth with the naked eye. I stretched about 10-samples from 0.5 per cent. to 10 per cent., and, after heating to 1,050° C., I found that the maximum grain growth occurred at about 2 ½ per cent. cold deformation. This I designated "the critical strain" for maximum grain growth. About a year ago I talked with Prof. Jeffries, who explained to me his ideas of grain growth. It occurred to me that it would be a very easy thing to check the strain hypothesis against the strain and temperature hypothesis, if we took a certain number of these strips, strained exactly alike and heated to different temperatures; in that case the maximum grain growth ought to appear at a different percentage of deformation for each temperature. These experiments showed that there was, as Mr. Jeffries shows in his present paper, a decrease in germinative temperature with increased cold deformation. The samples were stretched from ½ to 8 per cent. and heated for 10 hr. in hydrogen. Samples were introduced into a furnace previously heated to temperature. A maximum grain growth was obtained at 5 per cent. deformation, when heated to 750° C.; at 2 ½ per cent. when heated to 800' C.; at 1 1/4 per cent., if heated at 950°C.; and at 5/8 per cent.. when heated at 1,100° C. This shows very clearly that the germinative temperature decreases with the increase in cold deformation. The growth was very much more marked, however, at the high temperature, i.e., the grain grew more rapidly and attained a much larger size than at lower temperature. In considering the photographs (Fig. A) those along the lateral edges should be ignored because.

Jan 4, 1917

Discussion of the papers of DAVID H. BROWNE, Louis V. BENDER, and R. E. H. POMEROY, presented at the New York meeting, February, 1915, and printed in Bulletin No. 97, January; 1915, pp. 49 to 60, 73 to 81, and No. 98, February, 1915, pp. 445 to 453, respectively. E. P. MATHEWSON, Anaconda, Mont.-After hearing about the success of D. H. Browne with his furnaces, we in Anaconda decided we might venture into the field of pulverized coal for reverberatory smelting. We sent a delegation of investigators to see Mr. Browne and his work, and they returned, filled with enthusiasm, and said they would recommend it strongly. We thereupon asked for an appropriation, and after some delay obtained the same and fitted up one furnace to use pulverized coal. We copied Mr. Browne's practice and his selection of machinery for drying and pulverizing coal; and we also copied the burner he used, which was a standard article on the market. We got an expert coal-dust machinery man to design our plant, and were very glad we did so as we avoided some of the unpleasantness that had been experienced at other plants through fires and minor explosions.

Jan 5, 1915

By Arthur F. Taggart

The following conclusions on the work of the Hardinge mill are based on data furnished to the writer by the Hardinge Conical Mill Co. in the form of the mesh cards hereto appended. Energy units (E. U.) and relative mechanical efficiencies (R. M. E.) are computed by the "volume method" of Stadler.' Screen apertures used are the average apertures of testing screeps of the meshes given. i . Card 122. June 28, 1912. Vipond Porcupine Mines Co., Ltd., Schumacher, Ont., Canada. Ore from mill bin. Gangue, quartz and basalt. 4.5 ft. by 13 in. ball mill, Capacity, 48 tons per 24 hr. Charge, 4,000 lb. balls. Speed, 33 rev. per minute. Horsepower, 15 to 17. Water, 100 per cent. by weight. (50 per cent. ?) Product deslimed and oversise reground in pebble mill, see Card 113. Feed to mill through 2-in. mesh. Mesh Feed, Per Cent. Discharge, Per Cent.. + 1in. 5.50 ....... + 3/4. 28.00 + in. 30.00 ...... + 1/4in. 19.72 ....... + 10 10.87 2.10 + 20 2.42 8.00 -20 3.51 .....,. + 40 ....... 22.68 + 60 ...___ 10.50 4-80 ....... 11.80 + 100 ....... 3.90 -100 ....... 40.15

Jan 1, 1916

YEAR OF ELECTION 1913. FRANK DAWSON ADAMS, Montreal, Canada. 1921. WILLIAM CUTHBERT BLACKETT Sacriston, Durham, England. 1923. GELASIO CAETANI Rome, Italy. 1920. HENRY STURGIS DRINKER Merion Station, Pa. 1933. KARL EIKERS NEW YORK, N. Y. 1922. FEDERICO GIOLITTI Torino, Italy. 1906. SIR ROBERT A. HADFIELD London, England. 1928. JOHN HAYS HAMMOND New York, N. Y. 1921. FRANK WILLIAM HARBORD London, England. 1917. HERBERT HOOVER Washington, D. C. 1905. HENRI LECHATELIER Paris, France. 1931. WALDEMAR LINDGREN Cambridge, Mass. 1921. C. McDERMID London, England. 1913. EZEQUIEL ORDONEZ Mexico City, Mexico.

Jan 1, 1934

By E. Escobar Pallares

Footnotes to column heads and explanation of symbols are given on page 239. H.C.T. means the deep zone for High Cold Test crude oil. L.C.T. means the shallow zone for Low Cold Test crude oil. They occur in the same area. In the same area there are many shallow pits and some wells. In the column showing total oil production to the end of 1939 are included 355,997 bbl. from shallow pits before 1939. During the last year there was no production from shallow pita.

Jan 1, 1940

By E. Escobar Pallares

Footnotes to column heads and explanation of symbols are given on page 239. H.C.T. means the deep zone for High Cold Test crude oil. L.C.T. means the shallow zone for Low Cold Test crude oil. They occur in the same area. In the same area there are many shallow pits and some wells. In the column showing total oil production to the end of 1939 are included 355,997 bbl. from shallow pits before 1939. During the last year there was no production from shallow pita.

Jan 1, 1940

By John D. Hanks

INTRODUCTION Chevron's Uranium Mill is located near Panna Maria, Texas; 70 miles southeast of San Antonio. Designed by Kaiser Engineering, the Mill will process a nominal 2500 dry T.P.D. of uranium bearing ore containing 15% uncombined moisture. Earl Torgerson, San Mateo, California, is the consulting metallurgist on process design. Feed to the plant consists of a mixture of high, medium and low grade sandy day ore; the average grade of the ore will be 0.7% throughout the life of the project. The ore is delivered to the mill via truck and stored by type in individual piles on a flat storage area. The ore is fed by conveyor to a semi-autogenous grinding mill. The SAG mill discharge slurry is pumped either to a storage tank or to the first of five mechanically agitated leach tanks where both H2SO and NaC103 are added. Following leaching, the slurry is mixed with thickener No. 2 overflow before being pumped to a six-thickener, countercurrent decantation circuit where the solution containing uranium is separated from the leach residue. The residue is washed essentially free of solubilized U308 values at the sixth thickener and discharged to an adjacent tailings pond. The first thickener overflow, containing approximately 0.4 grams U308 per liter, is filtered for clarification and sent to the liquid ion exchange (solvent extraction) section. The pregnant aqueous solution is mixed with organic solvent containing amine on which the complex uranyl sulfate ions are absorbed. The immiscible aqueous and organic solutions are mixed and separated in each of the four stages of solvent extraction. The final pregnant organic is directed to a stripping section. A strip solution containing (NH4)2S04 (ammonium sulfate) and NH4C1 (ammonium chloride) is contacted and separated from the organic in each of the four mixer-settler units. The strip solution is mixed with NH3 and the uranium precipitates along with trace amounts of sulfate, chloride, and ammonia. After washing in a thickener, the uranium precipitate or yellowcake is centrifuged and dried in a multiple hearth roaster. Overflow from the yellowcake thickener is recycled back to the stripping section of the solvent extraction circuit. The dried yellowcake concentrate contains more than 98% U308; diluents include H20, ammonia, chloride, etc.. Impurity concentratons in the product are sufficiently low, after drying, to permit direct shipment to refinement installations. ORE RECEIVING Ore from one or more mines will be stored on a pad adjacent to the uranium processing mill. Ore stored in the area may total 200,000 tons or more, which is equivalent to over a two month treatment reserve for the mill. In addition to providing surge capacity, the proposed storage facility permits natural oxidation of the ore and affords an area which, in turn, improve plant U308 recovery and reduces consumption of oxidizing reagents. The uranium bearing ore is segregated at the storage area into several distinct types. One group can be identified by its sandy, clay-like matrix and will be distinguished by its U308 concentration of high, medium, or low. Other ores contain substantial quantities of carbonaceous shale, typical of ore in the area. Feed is recovered from any one or combination of piles, in accordance with operating requirements and recovery factors. The run-of-mine ore, at 15% moisture, is transferred to a stationary, 24-inch by 24-inch grizzly. Undersize material falls into a 280-ton surge hopper located below grade, while oversize material is removed for preliminary size reduction. A sump-pump is located at the reclaim hopper to recover excess mositure and ore spillage for processing. Plant feed is continuously drawn from beneath the hopper at an average rate of 120 tons per hour by means of an apron feeder. The hopper is equipped with a low level safety system to protect the apron feeder assemble. The ore is transferred to a belt conveyor, elevated and discharged into a semi-autogeneous grinding (SAG) mill. Water addition at the discharge point is automatically controlled by a feed rate, moisture analyzer system located on the belt conveyor. GRINDING Minus 24-inch ore, at a rate of 120 mosit tons per hour and cyclone underflow at a rate of 137 moist tons per hour are combined with a controlled 186 gallons per minute fresh, warm plant process water. The mixture, at an average 68% solids, is fed to the SAG mill. The viscous mass is subjected to grinding at a temperature moderately above ambient resulting from use of the 140ºF well water. The 16.5'x5.0' Marcy Mill is driven by a 500 H.P. A.C. Motor. The mill will rotate at 73.4% of critical speed or 14.06 R.P.M. Eight percent of the mill's volume will be occupied by steel grinding balls; 22% by pulp. The mill is designed to rotate in either direction, in order to obtain maximum lifter and liner life. The SAG mill is equipped with a trommel having ½ -inch slots for removal of oversize material at its discharge and the large or oversize material is collected and either recirculated periodically or discarded. The undersize slurry is diluted to 64% solids with the addition of hot well water or mine water to the mill discharge sump. The flow is automatically controlled utilizing data from a gamma density meter. The slurry from the mill discharge sump is pumped to hydrocyclones to classify the particles. Underflow from the cyclones, at 80% + 28 mesh, is recycled to

Jan 1, 1979

By Herbert F. Miller

For a long time I have believed that the gas- and brick-costs of open-hearth furnaces using prodncer-gas could be greatly decreased by a change in the design of the port, which would materially reduce the first-cost of the furnace, the rebuilding-cost, and the repair-cost. The defects of the present type of such furnaces, which has clone duty for so many years, may be studied in Fig. 1, in which A A are the two air-uptakes, B is the gas-uptake, and C the end of the gas-port. In the present type of furnace, C is practically 011 the edge of the bath and therefore combustion begins to take place at that point, but has no effect until the gas passes from 5 to 10 ft. into the hearth. As the furnace grows older, C moves back by reason of the burning or falling down of the arch. The furnace reaches its highest efficiency when C has moved a certain distance, but is still near enough to the bath for the overhead layer of air to hold the gas down on the bath, and far enough back to permit combustion to take place at some distance from the bath. This latter fact means that the temperature is sufficient to melt steel at the edge of the port. From this time on, the furnace decreases in efficiency. What is the reason ? As C moves further hack, the gas is released from the gas-port at a point where there is little or no overhead layer of air. The result is that the gas floats along the roof, with the air mostly underneath it. Why the air does not stay over the gas is readily seen in Fig. 1. The lines of draft naturally run parallel to the length of the furnace. The air-uptakes being on the sides and the gas-port in the middle, most of the air will naturally be drawn along the sides of the furnace and the layer of air will be thinnest over the gas, where it is most needed.

Jan 1, 1914

THE progress in lead smelting practice in the United States during 1930 has been along previously defined lines. Since most of the material treated is high-grade concentrate relatively high in zinc, practically all the plants have been forced to adopt double sintering. This generally results in there being' no matte fall, and most of the copper in the charge is recovered in the furnace dross. The furnace dross is . smelted with. scrap iron and flux .in small reverberatories, giving a shipping matte or speiss high in copper and low in lead. Details of this reverberatory. furnace practice vary at the different plants. There is a decided tendency toward moreintensive filtration of blast- furnace and sinter fume. Bag capacity has been in- creased by using higher pressures and more frequent shaking.

Jan 1, 1931

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 Samuel S. Adams

Potash, the generic term for a variety of potassium-bearing minerals, ores, and refined products (Table I), owes its importance as an industrial mineral to the potassium requirement of growing plants. The term "potash" originally referred to potassium carbonate produced by the leaching of wood ashes. This process, for which the first U.S. patent was issued in 1790, was the basis for the largest United States chemical industry in the early nineteenth century. The agricultural use of potash soon eclipsed the chemical applications following the German discovery in 1840 that potassium is essential to plant growth. The initial discoveries of large deposits of soluble potassium minerals, essential for agriculture applications, were made in 1857 in Germany and in 1914 in the United States. More than 90% of the 20.4 million short tons K2O produced in the world in 1970 (Eilertsen, 1971 ) was derived from marine evaporite deposits and approximately 90% was used in fertilizers. The potassium content of an ore, mineral, or product is customarily expressed as % K,O, a unit of measure which is neither a natural nor synthetic compound of potassium (1 .O% K is equivalent to 1.2046% K,O) . Geology Potassium, the seventh most abundant element in the earth's crust, is present in silicate minerals in igneous, sedimentary and meta- morphic rocks. Potassium is also a major constituent of many surface and subsurface brines (Table 2). Economic potash deposits are essentially restricted, however, to widespread, thick accumulations of marine chloride evaporite deposits. These deposits yield high grade, large tonnage ore bodies, many of which are amenable to low cost mining and beneficiation. The products from these deposits are, moreover, ideal for use in fertilizer because of the high relative solubility of the potassium chloride and sulfate evaporite minerals. World potash production and reserves for such de- posits so vastly overshadow other sources of potassium that the following discussion will be limited largely to potash deposits in marine evaporites with brief reference to certain potash-rich brines. Approximately 85% of current domestic production is from bedded salt deposits and much of the balance is from brines. Marine evaporite deposits are accumulations of salt minerals deposited in structural sedimentary basins through the evaporation of sea-water or mixtures of seawater and other brines. The salt minerals are precipitated in assemblages and sequences of assemblages as determined by the compositions of the brines and the solubility relations in the salt systems (D'Ans, 1933). The evaporation of seawater normally yields carbonate minerals as the first precipitates (Table 3). Further evaporation and concentration of the brine leads to the precipitation, in succession, of sulfate, chloride, and supersaline mineral assemblages including the salts of potassium and magnesium. The common minerals, ores, and products of potassium deposits are listed in [Table 1]. Many potash deposits contain accessory evaporite minerals together with a variety of detrital and authigenic silicates (Braitsch, 1971).

Jan 1, 1975