Search Documents

By Bernard K. Asdell

Georgia, a state seldom considered to be an important mineral producer, has one surprising feature-it is the nation's largest producer of kaolin. Kaolin is a highly important raw material in the paper, rubber, ceramic whiteware, paint and chemical industries. In 1965, more than 2.7 million tons of kaolin were produced in this state, a 150,000-ton increase over the preceding year, and production continues to climb. Strictly defined, the term "kaolin" applies to a group of hydrous aluminum silicates in which kaolinite is the predominant mineral. Kaolinite is inherently white, non-abrasive, chemically inert, and of a very fine particle size, ranging from sub-micron to 40-microns equivalent spherical diameter. An electron-micrograph of kaolinite is shown in Fig. 1. The particles finer than about 2 microns are thin, elongated plates, hexagonal in outline. The larger particles, coarser than 2 microns, are predominantly vermicular in outline with a foliated structure. Table I shows a typical chemical analysis of commercial, wet-processed kaolin compared to pure kaolinite.

Jan 11, 1967

By Thomas D. Henderson, Donald E. Crowell

INTRODUCTION This paper presents a "case history" of the steps taken to estimate capital and operating costs for a typical porphyry copper concentrator of ±9,070 metric tons (10,000 short tons) per day capacity. The concentrator described herein is hypothetical, but is based on experience and is, in effect, a composite of several actual projects. The numbers used are illustrative only and do not represent actual costs at any particular concentrator. These numbers are, however, representative of typical milling costs at one point in time, and. are sufficiently accurate to illustrate the cost estimating procedures described in this paper. It is not possible to publish actual, current milling costs and, in any event, actual cost figures quickly become meaningless in today's economic situation with various costs all rising at different rates. The paper is divided into three parts: (1) order-of-magnitude estimate, (2) feasibility study estimate, and (3) discussion of differences between estimated and actual costs.

Jan 1, 1978

By John A. Church

AT a time when the treatment of gold and silver ore9 by fusion, in opposition to the mill-process, is attracting so much attention in this country, it may be useful to consider what is done in a well-conducted foreign work. For this purpose I will ask the reader to accompany me to Lend, in Austria, a small but thoroughly organized

Discussion of the paper of E. S. Moore, presented at the Colorado meeting, Sep-tember, 1918, and printed in Bulletin No. 135, March, 1918, p. 687. W. F. SMEETH, * Bangalore, Mysore, India (written discussion ? )-Before dealing with the air blasts, I would like to clear up a geological point. The author states that the matrix of the conglomerate resembles a hornblende schist. This is a, misapprehension. The conglomerate

Jan 10, 1918

By Mark E. Smith

To allow recovery of gold values from ore which cannot be economically processed by the mill, Pinson Mining Company has developed a run-of-mine heap leaching facility. In order to estimate production scale recovery rates, reagent consumption and percolation problems, a series of pilot scale tests were performed. These tests typically consisted of 3,630 metric tons (mt) (4,000 tons) leach ore at a grade of .94 to 1.56 grams Au per metric ton (g/mt) (.03 to .05 oz. Au/ton). Test heaps were loader stacked to approximately 4.3 meters (14 feet) high. Information from these pilot scale tests was employed in the design and construction of the production scale facility. Parameters such as spray rate, leach cycle, sprinkler placement, and barren solution chemistry were determined by the pilot tests.

Jan 1, 1984

SINCE you have asked me many times in particular how those mirrors are made that are commonly called spheres,* and even though I have told you at other times, I do not wish to omit writing of it here again in detail, so that you may have as complete information as I can give you, both in order to satisfy you fully and because it belongs among the subdivisions of the subject that I have proposed. Concerning this, I first tell you that it was an ancient discovery, and in those times as today was celebrated, and worthily so. For the effects these mirrors produce are miraculous things incomprehensible to me, and the more I think about it the more I am bedazzled with wonder, nor do I know how to explain by theory of perspective the causes demonstrated by their effects. Marvelous indeed is the beauty of their shining clearness, but much more so is the fact that (according to the shape that the craftsman has chosen to give them) they reflect back the shadow of the things

Jan 1, 1942

By O. L. Kowalke

During the last few years the use of base-metal thermocouples has increased very considerably in various industries, due to the necessity for more precise control of temperatures. The base-metal couple has the advantages of being robust to a surprising degree, cheap as compared with platinum couples, sufficiently accurate for most operations, rapid in indicating changes in temperature, easily renewed or repaired, and of generating a much higher electromotive force than the noble-metal couples. There are, however, some factors, such as indicating and recording instruments, the insulation on the elements, the constancy and homogeneity of the wires, and the resistance to oxidation in the furnace, that limit the. Usefulness of the temperature-measuring device. It is the purpose of this paper to discuss in what manner these factors affect the usefulness of the couples.

Jan 9, 1919

By P. E. Price, N. J. Grant

DURING the course of creep studies in iron-chromium-nickel alloys, it became necessary to establish the limits of the two-phase ferrite-austenite field at 1300°C. The shape of this region, predicted from the iron-chromium and chromium-nickel binary

Jan 1, 1960

By J. B. Hiskey, G. Ramadorai

This paper presents the kinetics of leaching pure wulfenite (PbMoO,) with sodium sulfide solutions. Wulfenite dissolves in the presence of sulfide ion according to the following reaction: PbMoO , + S= PbS + MOO;. Synthetic galena is formed and molybdenum is released to solution as molybdate ion. The reaction follows the shrinking core model and the leaching mechanism involves mixed kinetics where both diffusion and chemical reaction are rate controlling. Molybdenum extraction is explained in terms of temperature, particle size, and sodium sulfide concentration.

Jan 1, 1977

By George Kenzy, Charles B. Manula

This paper introduces a philosophy of dynamic modeling. Here, the development of a simulation model of a coal mining system is described for the purposes of: (a) system design and selection of equipment for a new operation; (b) analysis of existing operation' for possible alterations, additions, or general improvements.

Jan 1, 1976

Jan 1, 1934

By S. Chander, V. N. Sharma

Nickeliferous laterite ore from Sukinda, Orissa (India), consists of very fine particles agglomerated into larger aggregates. The ore is chemically and mineralogically complex and presents many characterization and beneficiation problems. In this study the results of a detailed investigation to characterize the ore by several techniques are discussed. Various techniques used for characterisation include elemental analysis, electron microscopy, electronspectroscopy for chemical analysis, x-ray and electron diffraction, differential thermal and thermogravimetric analyses, EDAX analysis, Mössbauer and infrared spectroscopy. Generally one method compliments the other and it is shown that a combination of several techniques is necessary to fully characterize the ore. The scope and limitations of the techniques are also discussed.

Jan 1, 1980

By B. C. Mariacher, I. Hoffman

In 1952, beneficiated phosphate ore first began to move from the Oron plant of Negev Phosphates Ltd. in the Negev Desert to the super-phosphate plant at Haifa, Israel. Since that time this company has continually sought to overcome its natural handicaps affecting the operating efficiency and quality of the product in an effort to bolster the agricultural program of Israel and the development of an exportable commodity. The most serious deterrent to the development of a beneficiation process was the total absence of water. The Oron plant lies approximately 30 miles south of the irrigated regions of Israel with the nearest producing water well located about 10 miles to the northwest. The urgency of early phosphate production made it necessary to consider only dry processes in the initial operation. Fortunately, the ore was amenable to a dry process which yielded a usable concentrate assaying about 28.5 pct P2O5; but phosphate recovery was low. A description of the characteristics of the Negev ore should help to clarify the principles upon which the dry concentration is based.

Jan 5, 1961

By A. T. Tye

WHEN the roughing tables operated in 1923 were abandoned, all the coarse iron pyrite for-merly removed by the tables had to be ground to flotation size, which caused an increased power con-sumption of 2 kw.-hr. per ton. Recently, by increasing the tonnage, this has been reduced to a total of 16.6 kw.-hr. per ton. The cost of repairs has been slightly reduced by using an alkaline circuit instead of the acid mine water used in 1923. Other economies from elim-inating roughing tables and the finishing tables have more than compensated for the extra grinding and the total costs have remained practically the same, until the first part of 1927, when, with increased tonnage, the total cost has decreased to 72 cents and the repair cost to 9 cents. In 1923, with a combined gravity and bulk flotation flowsheet, the grade of concentrate was only 4.38 per cent copper. With preferential flotation this has in-creased to over 17 per cent copper. The tailing has decreased from 0.29 per cent -copper to 0.18 per cent. The copper recovery, instead of decreasing; as might be expected, has increased from 87.4 per cent to, 91.5 per cent. The silver recovery has also increased from 88

Jan 8, 1927

By D. E. Moore

The strength of a natural serpentinite gouge was measured at 400°C and an effective pressure of 100 MPa. The strength of the gouge decreased with increasing pore pressure to 50 MPa and then was nearly constant between 50 and 125 MPa. The samples at 50-125 MPa pore pressure slid stably, whereas those at 3-25 MPa pore pressure showed stick-slip behavior. Lengthening the pre-heating time to 72,000 s of samples at 100 MPa pore pressure led to increases in both the strength and the likelihood of sliding unstably. With still longer pre-heating times, the strengths decreased again and sliding once more became stable. The strength of the gouge at 3 MPa pore pressure was unaffected by changes in pre-heating time. A possible explanation for the results is that excess pore pressures are being generated in the gouge, causing the true effective pressure to be lower than the apparent value.

Jan 1, 1984

By Bruce A. Lamberton

In U. S. underground mines concrete work is not widely used. Timber and steel are cheaper, and there are few serious water problems. But in the Union of south Africa men dig deeper, more persistently, and probably more profitably than anywhere else on earth. Some gold mines near Johannesburg are below the 10,000 level and employ as many as 35,000 natives on a single property. Underground substations, pump chambers, and air conditioning plants have capacity to serve small cities. The complexity and extent of underground operations and the heavy subsurface water flows, especially in the new Free State gold fields, require heavy in a Deep concrete installations.

Oct 1, 1956

By John V. Beall

One Sunday night last month the phone rang and it was George Schenck from Penn State. How would we like to see a big scrap operation, he wanted to know. A few days later we were on the Connecticut turnpike headed for New Haven to visit a large scrap operation, M. Schiavone and Sons. George had a large clam basket in the back which he explained was for collecting trophies. The car shredder, he said, turns out some fancy metal shapes. In fact, they have gained a certain acceptance as objets d’art among George's friends and relatives. He thinks there may be a small, but possibly lucrative secondary market for shredded cars in the art world if the idea is imaginatively promoted. On the way to New Haven we received a briefing on the scrap industry. The scrap business grew from humble beginnings. Mostly it was started by a few immigrant Jews who collected junk in hand- or horse-drawn carts. The fortunate one might even have had a truck. Before proceeding further, we hasten to point out that the word "junk" is strictly taboo among scrap people, who prefer to refer to their industry as the "secondary metals industry."

Jan 1, 1970

By Jerrold Marcus

The peninsula is roughly 700 miles long and 180 miles wide. The southern portion is the American-sponsored Republic of Korea and the northern half is the Soviet-promulgated People's Democratic Republic of Korea. The area of South Korea is almost 40,000 sq miles, about the size of the state of Maine, and contains a population estimated at 22.5 million. Prior to annexation by Japan in 1910, the Korean economy was based on a system of self-sufficient farming units, but with Japanese occupation it was geared to Japanese economy. Emphasis was placed on supplying raw materials for Japanese industry and food surpluses to help feed Japan, and on providing a connecting link with Manchuria, traditionally a major raw material source for Japan. Small metal refineries, ore processing, and semi-finished goods manufacturing units grew into existence in the northern part of Korea, where much of the electric power is generated. Under Japanese domination, the south remained essentially agricultural. Food productivity was increased, although manufacture of elementary consumer goods was stimulated for Japanese markets.

Apr 1, 1956

Jan 1, 1912

W. N. Triplett (Geology of the Silver-Lead-Zinc Deposits of the Avalos-Providencia District of Mexico, P. 583) was born in Tecumseh, Mich., and attended the University of Michigan and Massachusetts Institute of Technology. From 1912 to 1917 he worked for Moctezuma Copper Co., a Phelps Dodge subsidiary at Nacozari, Sonora, Mex. He served in Army as Second Lieutenant Field Artillery from 1917 to 1918 and from 1919 to 1922 returned to Moctezuma Copper Co. From 1922 to 1952 he has been with Compania Minera de Penoles, S. A., a subsidiary of American Metal Co., Monterrey, N. L., Mexico in Unit Dept. as chief geologist and at present is consulting geologist. Mining geology and operation is of particular interest to Mr. Triplett. He presented a previous paper before with M. W. Hayward entitled, "Occurrence of Lead-Zinc Ores in Dolomitic Limestones in Northern Mexico." Besides being an AIME member, he holds membership in Society of Economic Geologists. Fishing, hunting and photography are his favorite hobbies.

Jan 1, 1952