Search Documents

By John P. Bernardi, Ralph B. Hall

Past and present phosphate production in the central Florida phosphate district has been predominantly from the unique Bone Valley formation. As these lucrative reserves are depleted, production will shift to the Hawthorn formation in all areas, but particularly so within the southern extension, where vast potential reserves of low grade phosphates exist. Use of existing plants can be extended for some years by mining deeper into the underlying Hawthorn formation, and by mining previously ignored peripheral areas if erratic combinations of the two formations. Hawthorn Production, as compared to the Bone valley, will be characterized by lower grade; lower tonnage yield, lower pebble percent of product, higher mining ratios, higher slimes (- 150 mesh) content, and more complex mining and beneficiation problems. Geological control and more sophisticated operational procedure; will become increasingly more important as the lower quality reserves replace Bone Valley production.

Jan 1, 1981

By William Reynolds

THIS paper deals with the results of a study of the application and development of mining machines for cutting out and removing dirt bands in bituminous coal beds. FACE PREPARATION When one or more dirt bands1 occur in a seam of coal, the problem of elimination of impurities becomes manifest. The degree of complete-ness to which these impurities are removed at the face has an important bearing upon labor costs, haulage costs and outside cleaning costs, and often the ash content of the product is markedly affected. Yet, because the present-day miner is paid for the number of tons he loads he often lacks interest in the quality of the coal. To insure a clean product, a system of penalties for dirty coal is enforced, but control of extraneous impurity content in the loaded coal is often inadequate and ineffectual when coal and banded impurity are shot as one. It seems only logical that to reduce the amount of impurities by proper face preparation before the men are permitted to load the coal is the most efficient method of preparation.

Jan 1, 1936

By E. H. Crabtree

Research on the iron ranges begins to bear fruit in big plant construction -Big coppers raise capacity, build at new Arizona, Michigan, Nevada, properties - Hydrometallurgy comes to fore with new uranium ore treatment and the Chemico process for nonferrous metals -

Jan 2, 1953

By D. J. Spottiswood, C. N. Robinson, D. E. Spiller, E. G. Kelly

This paper describes the performance of a new design of spiral that is optimized for fine coal cleaning. Reduced Performance (Tromp) curves are presented to compare this spiral with the older design, as well as with other commonly used coal cleaning equipment. As an aid to equipment selection and circuit design, data are also presented to show how variables, such as flow rate, pulp density, and particle size, affect efficiency and the separation specific gravity.

Jan 1, 1985

By Herbert Herman, M. E. Fine

THE first decomposition product of a supersaturated aluminum-rich A1-Ag alloy at low tempera- tures is Guinier-Preston zones.'-, The zones are ideal and each consists of a spherical shaped silver-rich cluster about 16 A in diam syrounded by a silver-poor shell approximately 72A in diam.' The composition of the two regions is not known with certainty., After quenching from the solution anneal, these zones form rapidly on aging at temperatures as low as -30°C.5 The rate of zone formation increases with aging temperature; the activation

Jan 1, 1961

ALTHOUGH iron ores occur in many parts of Sweden the two principal deposits are those at Grängesberg (see accompanying map) and at Kiirunavaara-Gellivare. Both of these deposits are con-trolled by a holding company, Trajikaktiebolaget Grängesberg-Oxelösund, which sells annually about one-half of, the iron in ore traded in world markets and has a fleet of 24 seagoing ore boats, with a total dead weight capacity of 172,500 tons. Because of its pre-eminence in international iron ore trade a brief outline of its operations will be of interest. ORE DEPOSITS OF GRÄNGESBERG The Grängesberg deposits have been known since the Middle Ages, but up to the middle of the nineteenth century the ore was transported from the mines to the furnaces in winter in. sleighs. Railway building began in 1853, and in 1873 the complicated structure of capital investment was tottering, but the basic bessemer process created a demand for ore high in phosphorus, as this is, and refinancing on the initiative of Sir Ernest Cassel put the principal operation on a firm footing. There are numerous property owners in the district, but they are all controlled by a joint administration board, and 90 per cent of the ore is produced by a subsidiary of the Grängesberg company from proper-ties which it either owns or leases. The ore, a mixture of magnetite and specular hematite, is in lenticular bodies, dipping about 70 E. in. fine-grained gneiss, and contains about 61 per cent Fe and 1 per. cent. P. There are two principal veins; the total ore reserves to a depth of 500 meters are estimated at 150,000,000 tons. As seen in the accompanying illustration, the ores were first worked in open cuts, but eventually underground shrinkage stoping was adopted. Difficulties were encountered in the support of the workings and from the freezing of the ore in the stopes, so slicing was adopted, although block-caving is used in one place. Most of the mining is now done at a depth "of 150 to 190 meters. The present annual output is about 1,400,-000 tons of crude ore, which yields about 1,000,000 tons of concentrate after being subjected to magnetic con-centration and jigging.

Jan 1, 1927

By Edward H. Robie

IN many ways, the Annual Meeting of the Institute in February was the most successful yet held. Attendance surpassed even that of the 75th Anniversary Meeting in 1947 with its international flavor. The number of technical sessions and the number and quality of papers presented almost certainly set a new record. The banquet was the best attended of any yet held even though the price reached a new high. Despite the demand for almost 1700 tickets to the banquet, some felt that the price-$13.50-was higher than they could afford. There are two points of view: One is that this is the big social event of the year for members and that it is worth from three to five dollars more to have it at the Waldorf and to have a luxury menu, as we did this year, with turtle soup, a fish course, guinea hen for the entree, and wild rice (which we understand is $3.50 per lb) for a vegetable. The other point of view is that a seven or eight dollar banquet of more simple food at the Commodore Hotel would more than make up in appeal, especially to the younger and less well-heeled members, what it would lack in glamour.

Jan 1, 1952

By Wilbur Nelson

THE year 1924 showed even less drilling in Kentucky and Tennessee than the preceding year. The operators in this section, however, are anxious to resume development work and are only waiting for a higher market for crude oil before starting such a program. In Kentucky, during 1924, 1605 wells were completed, the combined initial daily production of these wells being 25,599 bbl. Of the total number of wells drilled 1176 were oil wells, 61 gas wells, and 368 were dry holes. The average initial production of the oil wells was 21.8 bbl. per well. In Tennessee, 28 wells having an initial daily production of 1199 bbl. were completed during 1924. Of these, 3 were oil wells, 6 were gas wells, and 19 were dry holes. The initial production of the three oil wells was 400 bbl. Of the total number of wells drilled in Kentucky in 1924, 73 per cent. came in as producing wells; and of those drilled in Tennessee, 10 ½ per cent. came in as producing wells and 20 per cent. as gas wells. In Tennessee, during 1924, wildcatting dropped off considerably and only about one-half as many wells were drilled as in the preceding year; in Kentucky, on the other hand, there was only a slight curtailment in drilling, there being 1943 wells drilled in 1923 as against 1605 in 1924.

Jan 3, 1925

By Fred D. DeVaney

W. O. Philbrook (Carnegie Institute of Technology, Phila.)—Mr. DeVaney's paper is a valuable addition to the growing technology of the magnetic roasting of lean iron ores. His furnace is ingeniously designed to permit close control of the process and to achieve high thermal efficiency by counter-current heat exchange and the withdrawal of both solid and gaseous products at relatively low temperatures. The principle of using a lean reducing gas to avoid over-reduction of the ore even at high operating temperatures (for rapid re-action rate) is thoroughly sound. The gas analyses and flow rates reported, however, are internally incon- sistent and render suspect any details of a heat balance based upon them. While it is entirely proper to consider the entrant gas as a reagent and to account only for the heat evolved by consuming a portion of the gas, many operators are accustomed to a heat balance using the total calorific value of the reagent supplied; and comparison of heat balances made with different bases of calculation can be quite misleading. Since Mr. DeVaney's paper is likely to be cited frequently in future discussions of magnetic roasting processes, it seems worth while to point out the internal discrepancies and to give alternate values of heat requirements for different bases of calculation.

Jan 1, 1954

[ ]

Jan 1, 1938

Jan 1, 1890

Jan 1, 1947

By Richard A. Conkling

A shale layer, buried beneath two or three thousand feet of strata, in some instances, will upon folding become thicker in the synelines and thinner on top of the anticlines. This can be accounted for, in part, by the stretching on the crests of the fold and the compressing in the troughs; but this will by no means account for all of it, as is shown in the example herein set forth. It is my firm belief that the rest of the thickness is due to flow. What causes the movement, however, does not concern us here, SO long as there is movement, for this article purposes to show its effect upon the producing area of different sands. It is the author's hope, in this way, to drop a hint or two that may be valuable to the oil geologist, in making estimates of future productions and values of oil properties. An example will be given from property in the famous Gushing Pool in northeastern Oklahoma, where the author has had occasion to make a detailed study before recommending some property to his company, and has then been able to watch the results of this work. The author never mapped the surface structure in this pool, as this had been done by Frank Buttram when he was with the Oklahoma Geological Survey. We are using, therefore, a section of his map in this article for our surface contours. The main east dip comes farther east than this section shows. From the 10-ft. contours in Fig. 1, it will be seen that the surface folding is very slight, but in the contour map of the Bartlesville sand (Fig. 2), which was the greatest producing sand, we see much more complex folding. It seems that the folding becomes greater with the depth. Folding may have started in Middle Pennsylvanian times and continued through the Upper Pennsylvanian which is found at the surface. This may, or may not, have been the cause of the increase of folding with depth. However, the fact that mostly concerns us is the interval of shale between the Bartlesville sand and the Tucker sand. The Tucker is the next productive sand below the Bartlesville. Not enough wells have been drilled to the Tucker sand to make a contour map of it, but

Jan 1, 1917

By Don Blackmar

THE production of non-ferrous secondary metals has become a large and important industry in the United States, and deals with practically every type of manufacturing concern. Its business is unique in that it generally buys from its customers as well as sells to them, whether they are individuals, cities, corporations, or the United States government. Its operations are of vital importance to the success and prosperity of many of the nation's most important manufacturers; yet there are few industries about which less is generally known by those outside it, whether concerning the magnitude of its operations or the details of its actual technique. The industry itself is to blame for this meager publicity, because its technical men have made few attempts to openly exchange ideas, in spite of the excellent examples set by the iron and steel or the copper and brass industries. Whether this is due to the ancient shroud of secrecy generally supposed to cover smelting operations, or because its technical men actually felt that the industry was too puny to be interesting, is hard to say. This paper will consider its subject in a general way, attempting to show something of the size and importance of the industry, as well as its fitness to do its work well. Attention will be called to the sound economic reasons for the handling of non-ferrous wastes by specialists, and to the often unseen losses of metals and labor which occur when manufacturers reclaim their own metallic wastes.

Jan 1, 1928

By Robert M. Dreyer

Although lateritic ore deposits are relatively flat-lying, surficial ore bodies, the evaluation of lateritic bauxite and nickel deposits is among the most difficult problems confronting an economic geologist. Laterite is a soil formed under tropical conditions resulting in the concentration, within the soil zone, of certain trivalent metals-principally iron and aluminum, but also, locally, nickel and manganese. The soil zone is divided into two parts: (a) the true soil or lateritic zone and (b) the zone of partially altered bed rock or saprolite. Whereas bauxite generally is confined to the lateritic zone, some nickel deposits occur in both the laterite and saprolite zones. The evaluation of bauxite and lateritic nickel deposits thus has both similarities and differences. These ores have been formed by supergene, soil-forming solutions moving downward through zones of widely varying permeability within the weathering rock. Because the permeability varies widely, both vertically and laterally, the extent of weathering may vary greatly within short distances. Because the weathering process varies widely, the degree of metal concentration may also vary widely. It is not at all uncommon for a laterite to change, within a few centimeters, from a virtually valueless rock to a high grade ore. Moreover, the depth of weathering, and hence the depth and form of the ore profile, vary greatly. Obviously, for this type of deposit, a few grab samples or a few drill holes are virtually worthless. The evaluation of such a deposit requires a sophisticated statistical study based on thousands of carefully selected samples. As a rule of thumb, the cost of evaluating a large bauxite or lateritic nickel deposit will be about one cent per ton of ore in the ground. Thus, the cost of evaluating a several hundred million ton deposit may be considerable.

Jan 8, 1978

Jan 1, 1935

[ ]

Jan 1, 1938

By Carl Swartz

ALTHOUGH a number of articles appeared during the war advocating the use of cadmium in lead-tin solders, very little information of value can be found in the literature regarding the properties of solders containing cadmium. In most of the published articles the cadmium seems to have been considered merely as a partial substitute for tin in a tin-lead alloy rather than as an essential constituent of a ternary alloy. The primary object of the substitution of cadmium for tin was to lessen the amount of tin required, at a time when the latter was scarce and high-priced, and thus to produce a cheaper solder. While this object was accomplished, the new properties resulting from a change from a binary lead-tin alloy to a ternary lead-tin-cadmium alloy were not given proper consideration in many cases. For the past few years, the American Smelting & Refining Co. has been marketing a very considerable amount of cadmium in the form of lead-tin-cadmium alloys for use as solders for certain special purposes, and the successful use of these solders suggested that if more extensive knowledge were available concerning the properties of lead-tin-cadmium alloys of various compositions their field of usefulness might be materially extended. The investigation described in the present paper was undertaken to obtain this information and, by means of tests under conditions approaching those of practical use, to determine the suitability of cadmium solders for various purposes.

Jan 1, 1928

By Leonard Larson

DURING several years immediately preceding the adoption of wet-charge smelting at McGill, various necessary conditions affecting this procedure, such as plant rearrangement and the metallurgical nature of the concentrate produced at the concentrator, were fully considered. Wet-charge smelting is not altogether novel to the recently recon-structed smelter at McGill. A number of years prior to this improve-ment, when flotation methods were initiated at the concentrator, large tonnages of wet and (at that time) sticky flotation concentrate were charged directly into the reverberatory furnaces, because of the difficulty in handling the entire tonnage in the roasters. The plant had excess reverberatory units and this surplus furnace capacity was utilized to smelt raw flotation concentrate. During the years 1927 and 1928, a number of actual operating furnace test runs were made to determine in principle the feasibility of wet-smelt-ing operation. Results were encouraging, and in November 1932 the roasting plant was shut clown. For some time thereafter the wet feed was delivered directly to the reverberatory side-charging calcine hoppers already in place. Feeding the wet material through the old calcine hoppers and charge holes into the furnace involved considerable labor, but under the conditions existing at that time it was desirable to continue wet smelting even under the handicap of this laborious procedure. The smelting plant during this period was on a curtailed production basis, operating only about 15 days per month. The alternate starting up and shutting clown of the roasting plant presented a difficult problem and charging the wet material directly to the furnace entirely eliminated this difficulty. The roasting plant was never operated thereafter.

Jan 1, 1938

By H. Ries

IN THE marketing of mineral products, it is always highly desirable for both the producer and the consumer to be able to discuss things in a common language, and this can only be done if there are standard methods for expressing the properties of the raw materials. Having developed such a form of expression, the next step would be the making of specifications, which may serve as a basis for selecting raw materials. Considering the large number of non-metallic minerals that are used, there are not a few for which there are no standard laboratory tests to be used in determining their properties, or even standard specifications on which grades or market price may be based. Indeed in many cases the consumer simply requests the producer to submit samples, and rejects or accepts them without any explanation. Could the producer know in advance just what the consumer needed, time and money might often be saved. It appears to the writer that it is of the highest importance to devise standard laboratory tests wherever possible, as this enables the consumer to state definitely what he needs, and is of great assistance to the producer. It should also work to reduce misunderstandings and disputes. 'In the case of sands, we find that they show a wide variation in their character, ranging from those that are so coarse as to be of gravelly nature to those that are so fine that they might be classed as silt; and from very clayey ones to those that are practically free from clay. For this wide range of sands, we have a corresponding variety of uses, which are based mainly on the physical properties of the sand, although these are not always very definitely stated. The chemical composition need rarely be considered, if the sand is of siliceous nature. To determine and express these properties there should be standard tests, which are to be followed in all cases where the material is tested in the laboratory.

Jan 1, 1926