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By F. McIntosh Galbraith

This paper describes the use of the magnetometer, under geological direction, in exploration of the Sudbury nickel district. The writer's experience at Falconbridge has led him to the belief that only through detailed work, and by careful correlation of both geological and geophysical results, can geophysical prospecting methods be applied successfully to mining exploration problems. It is hoped that the basic technique described in the paper will be found to have general application. Introduction Within the past 20 years, geophysical methods of prospecting have become solidly established in the field of petroleum exploration. They have not, however, been similarly adopted by the mining industry, although mining is a far older craft and should be the more advanced in its technique. While, therefore, it is almost a routine matter to have geophysical surveys performed in a new area being tested for oil, a new metal-mining district is usually teeming with prospectors and promoters long before the technical man appears on the scene. Even then, only the more primitive engineering methods are customary in the early stages of exploration. Three factors are chiefly responsible for this situation, The first is the difference between oil pools and ore deposits in their geological modes of occurrence. While most of the known metallic ore bodies have been found outcropping at the surface, petroleum deposits are characteristically buried. This does not mean that all ore deposits outcrop, but neither does it mean that we should rely on "wildcatting" to discover blind ore bodies. The second factor is the relative scale of metallic lodes and accumulations of petroleum. In areal extent, a metal-bearing vein deposit is typically a much smaller geological feature than an oil pool. Presenting a narrower target, it requires closer shooting to score a direct hit. And finally, there is the need, in mining work, for close correlation of the known local geology with geophysical observations. This becomes of increasing importance as the size of the objective diminishes. A geophysical disturbance on a large enough scale will be detected under almost any circumstances and by almost any technique; without benefit of geology, however, the significance of a local anomaly may easily be misread. Campaign at Sudbury In the Sudbury nickel district of Canada, new deposits of nickel and copper have been discovered recently by magnetic methods, under geological supervision. A campaign of exploration, designed to encompass the district eventually, was set in motion in the spring of 1935. After six years, a new and important Ore body has been discovered and its continuity established to 1000 ft. in depth; several areas have been eliminated; and a number of possibilities remain to be tested. This has been accomplished with the expenditure of less than $$I50,000-—including the cost of all diamond drilling. The responsibility for carrying out this campaign was entrusted by the company to its Geological Department, and the under

Jan 1, 1946

By F. McIntosh Galbraith

This paper describes the use of the magnetometer, under geological direction, in exploration of the Sudbury nickel district. The writer's experience at Falconbridge has led him to the belief that only through detailed work, and by careful correlation of both geological and geophysical results, can geophysical prospecting methods be applied successfully to mining exploration problems. It is hoped that the basic technique described in the paper will be found to have general application. Introduction Within the past 20 years, geophysical methods of prospecting have become solidly established in the field of petroleum exploration. They have not, however, been similarly adopted by the mining industry, although mining is a far older craft and should be the more advanced in its technique. While, therefore, it is almost a routine matter to have geophysical surveys performed in a new area being tested for oil, a new metal-mining district is usually teeming with prospectors and promoters long before the technical man appears on the scene. Even then, only the more primitive engineering methods are customary in the early stages of exploration. Three factors are chiefly responsible for this situation, The first is the difference between oil pools and ore deposits in their geological modes of occurrence. While most of the known metallic ore bodies have been found outcropping at the surface, petroleum deposits are characteristically buried. This does not mean that all ore deposits outcrop, but neither does it mean that we should rely on "wildcatting" to discover blind ore bodies. The second factor is the relative scale of metallic lodes and accumulations of petroleum. In areal extent, a metal-bearing vein deposit is typically a much smaller geological feature than an oil pool. Presenting a narrower target, it requires closer shooting to score a direct hit. And finally, there is the need, in mining work, for close correlation of the known local geology with geophysical observations. This becomes of increasing importance as the size of the objective diminishes. A geophysical disturbance on a large enough scale will be detected under almost any circumstances and by almost any technique; without benefit of geology, however, the significance of a local anomaly may easily be misread. Campaign at Sudbury In the Sudbury nickel district of Canada, new deposits of nickel and copper have been discovered recently by magnetic methods, under geological supervision. A campaign of exploration, designed to encompass the district eventually, was set in motion in the spring of 1935. After six years, a new and important Ore body has been discovered and its continuity established to 1000 ft. in depth; several areas have been eliminated; and a number of possibilities remain to be tested. This has been accomplished with the expenditure of less than $$I50,000-—including the cost of all diamond drilling. The responsibility for carrying out this campaign was entrusted by the company to its Geological Department, and the under

Jan 1, 1946

By L. E. Wilsey, W. G. Bearden

This paper presents results of analysis of the effect of fracturing on initial flow rates and on ultimate recoveries from low capacity oil formations. This analysis shows that even in formations of permeability as low as 0.1 md, large fracture treatments can yield oil recoveries and production rates approaching those of high permeability formations. Field production information is shown which supports the analytical work. INTRODUCTION Often hydrocarbon bearing formations are discovered which, while they are known to contain large quantities of oil, will not produce at commercially attractive rates without special well stimulation. Attempts to solve this problem led to the development of such techniques as underreaming, shooting, acidizing, and recently hydraulic fracturing. These methods of stimulation have been highly successful in many fields. All of these treatments, however, affect only the pay section near the well bore and therefore owe their success to circumventing and overcoming local permeability reduction about the well bore. It has been the belief that in treating wells to stimulate production in which there is no permeability reduction near the well, the maximum possible production rate increase would be of the order of two or fourfold. Hence, it has been concluded that fracture treatment of uniformly low capacity (permeability times thickness) formations could meet with but limited success. It is the purpose of this paper to show that the use of fracture treatments much larger than usually used can yield commercially attractive producing rates and high recoveries even in formations of permeability less than 0.1 of a md. PROCEDURE In order to illustrate the effects of fracturing, an analytical study of some hypothetical systems was made in which one factor at a time was varied to show what is important in recovering oil from fractured wells. It was assumed that a horizontal fracture of relatively high fluid-carrying capacity extended from a well bore. The presence of such a fracture will cause a marked influence on the flow pattern and pressure distribution in the formations, with the net effect being to reduce tremendously the resistance to flow into the well bore. A diagram of the resulting flow pattern and pressure distribution is illustrated in Fig. 1. Immediately after production commences, the principal flow of fluid is vertically from the formation flanking the fracture, into the fracture, and then into the well. After sufficient oil and gas have been produced to lower the pressure in the formation adjacent the fracture, oil and gas will begin to flow in a radial manner into the fracture from the formations beyond the end of the fracture. In calculating the performance under such conditions. the material balance or conservation of matter equation and equations of flow were solved simultaneously by a stepwise method of calculation. Flow rates were found by determining the pressure distribution, as illustrated

Jan 1, 1955

By H. L. Riley, B. W. Gandrud

AS far as the present writers know, this system of flotation has not been used elsewhere in this country, but in the last couple of years it has been introduced, with minor variations, at one plant in England and one in Wales.' The system has been described and discussed in a number of publications.2-5 The following is quoted from an abstract of the latest of these,5 a paper presented at an International Conference on Industrial Combustion in 1952. On the basis of experience to date with the commercial plants, it is believed that the kerosene-flotation process incorporates all the necessary elements to make it greatly superior to anything else now available for treating of fines in wet processes of coal preparation. Additional study and investigation are still needed, however, to determine if certain phases of the process can be improved to such an extent as to make it generally satisfactory and acceptable to the industry. Further improvements will be needed with respect to the capacities of the flotation cells and the reagent consumption. The situation referred to above explains why an investigation is being made of the possibilities of achieving better cell capacities. Results obtained from this investigation, which is still in progress, are believed significant with regard to both cell capacity in general and the relation of cell design to cell capacity in particular. Commercial equipment now being used in a laboratory-type investigation should have performance characteristics similar to those of the larger machines. Equipment and Procedures: All flotation tests have been made in a standard Denver sub-A 24x24-in. unit cell of 12-cu ft volume. Cell modifications to make it more suitable for the tests were an adjustable front-wall section for varying cell depth and a perforated scraper-drag assembly for removal of the float product. There is also an apron dry-coal feeder, a gravity-feed water supply, reagent feeders, and a centrifugal pump that feeds the mixture of coal, water, and reagents into the flotation cell. A wattmeter connected into the drive-motor circuit records the power requirements of the impeller throughout each run. Dry coal, water, and reagents are all fed through a pan-type intake to the feed pump. A Sturtevant blower was set up to furnish air for supercharging. A centrifugal pump with a garbage-can intake provides for disposal of refuse flow to an outside settling tank. Figs. 1 and 2 show the flotation cell; Fig. 2 also illustrates the blower for supercharging. For purposes of this investigation, the percentage by weight of the feed coal recovered in the float product under a standard set of conditions has been considered as the criterion of cell capacity. The authors realize that such a criterion may be somewhat unorthodox, as the term cell capacity is usually understood to refer to feed input and ordinarily takes into account the ash analyses of the float product and refuse. However, the word capacity is flexible enough so that Webster gives one definition as maximum output, a definition which seems to justify, at least partly, acceptance of the above criterion. It has been the authors' experience in the Birmingham district that the ash-reduction efficiency of the coal-flotation process is generally satisfactory and that the only real problem is to increase the rate of float recovery so that the feed rate to any given bank of cells can be increased without undue loss of coal in the refuse. Originally it was planned to operate the flotation cell to simulate continuous operation during sampling periods. It was assumed that operating for reasonable time with feed coal, water, and reagents turned on would stabilize conditions so that the weight of float coal discharged during a fixed time interval would be an accurate measure of the rate at which the coal was being floated. It developed, however, that this supposition was erroneous. The float coal, caught for fixed time intervals and weighed, gave widely varying results in duplicate runs. Efforts to correct this trouble failed, and it was decided to try to operate on a batch-test basis, whereby all the float coal produced during a run on a known weight of feed coal would be caught in tubs, dewatered, and weighed. This method gives consistent and reproducible results, with total float product weight rarely varying by more than 3 or 4 pct on duplicate runs. The standard test procedure is as follows: A 132-lb sample of dry feed coal is weighed and placed in the feed hopper. The feeder is adjusted for a rate of 800 lb per hr. Feed water and reagents are turned on, and the feed and refuse pumps are started. One minute later the impeller is started. Six minutes are allowed for the cell to fill up with the water-reagent mixture. The feed of dry coal is started at the end of this 6-min period. One minute later the float-coal removal drag is started. The float coal is caught in one tub for the first 6 min after the flow of feed coal starts. Tubs are then changed, and the float coal is caught in a second tub until the feed coal runs out, when the tubs are again interchanged to catch the float coal for the remainder of the run in the first tub. The cell is kept running for 3 min with the water and reagents on after the feed stops to allow residual float coal to be removed. At the end of a test the wet float coal in both tubs is weighed and the total weight recorded. The product in the second tub is used for moisture determination and screen-size analyses. When the

Jan 1, 1956

By Joseph Kelly

DEPLETION of anthracite resources in Lackawanna County, Pennsylvania, has forced the recovery of coal tracts formerly considered unminable. Chief among these are the large areas of outcrop coal lying on a heavy pitch on the mountain sides, abandoned thirty or forty years ago as too costly and too hazardous to mine. The old companies, in many instances, stopped their chambers 80 or 100 ft. hack from the actual outcrop, and then dropped back another 100 ft. before starting to rob the pillars, thus leaving large areas of coal. Recovery of this coal naturally leads to mining hazards not encountered years ago. The first step is to sink a slope from the surface with the pitch of the vein, and then drive counters across the pitch as close to the robbed area as proper protection for the lower side of the -counter will permit. Next, the old chambers are advanced or new ones driven in the solid, as the conditions require. As these chambers approach the outcrop the real safety work begins-that of preventing the miner from being buried or locked in by an avalanche of mud.

Jan 1, 1936

By J. E. Lawver, G. L. Samsel

The success of many mineral dressing processes, including froth flotation and electrical concentration, depends largely on knowledge of physical and chemical structures of the mineral surfaces involved. As a general rule solids have surface layers, usually invisible by optical tests, that differ from the substratum. To the mineral engineer, therefore, a knowledge of the surface structures of minerals is of paramount importance. During the past decade one of the most powerful tools in the study of froth flotation mechanisms has been the use of radioactive tracers, but this technique usually cannot give definite information regarding the chemical changes that may or may not have occurred at the surface.

Jan 5, 1959

By John F. Havard, Armine F. Banfield

Sooner or later, we all get involved in the economic study and valuation of a mineral deposit. To communicate clearly the necessary information, we must scrupulously use various terms with specific meaning. All these terms-such as ore, exploration, development, production, reserves, proven ore, probable ore, possible reserves, resources, as well as similar terms applying to coal-are continually on the lips of anyone who reports on the economic aspects of a mineral deposit at the exploration, development, and production stages. The meaning of these terms is even more important in feasibility studies to determine whether a deposit should be put into production. Finally, careless use of these terms in reports published for public financing may, and sometimes does, lead to prosecution of the writer for misleading information.

Jan 7, 1975

Jan 1, 1887

Jan 1, 1884

By D. E. Swets, P. C. Frank, D. L. Fry

THE hydrogen-steel system has received considerable attention in the past several years. Recent experiments in this laboratory have shown that another group of operations, namely, sanding and grinding,' must be added to the already well-estab- lished list of phenomena that cause hydrogen to permeate steel. Qualitative tests which have been made with a very sensitive ion-gage type of detector similar to that used by Norton,' showed that sanding a steel surface caused hydrogen permeation. A metal type 6~6 vacuum tube was used as the ion gage with an electrometer to measure the ion c~rrent.~ The protective enamel coating was removed from the tube.

Jan 1, 1959

Jan 1, 1943

By Malcolm C. Bridges

A review of the application of geomechanics to open stope mining in Australia was recently undertaken for the Australian Mineral Industries Research Association (AMIRA). It compiled the current state of geomechanics and its application to open stope mining, and recommended avenues of research which should be supported by the industry. Information was compiled for eleven mines which use the method. This included their geological setting, the performance of the mining and evolution of the method, properties and behaviour of rock and backfill, and techniques for measurement and analysis. Open stoping accounts for about two-thirds of production from underground mines in Australia. In the future this proportion will progressively increase and the method will become more complex. Overall, the method is being sucessfully applied, but its full potential is not being achieved because a range of problems and limitations are evident within the mines. Many of these are common to several or more mines. These include: zones of poor ground conditions that delay access and stope development; crown pillars that are irrecoverable; substantial overbreak from the walls and backs of stopes; and lack of a widely accepted method to design systems of stopes. Generally, geotechnical information and techniques for applying it to mining are well-developed. However, it nee

Jan 1, 1983

Executive-A. R. Ledoux, chairman. Membership-J. V. W. REYNDERS, chairman. Finance-J. V. N. Dorr, chairman. Library-E. GYBBON SPILSBURY, chairman. Papers and Publications--BRADLEY STOUGHTON, chairman. Nominations-Pope YEATMAN, chairman.

Jan 11, 1919

Jan 1, 1945

By Nathaniel Arbiter

INTRODUCTION Almost seventy-five years ago problems in the recovery of sulfides from then designated slime fractions were the impetus for the development of flotation. The fall-off in recovery by gravity methods below about 200-mesh, and the shift from coarser vein deposits to more disseminated ores, particularly for copper, provided the background for flotation's rapid advances. Although the ensuing years have witnessed major improvments both in flotation reagents and in flotation machines, many problems are still with us. And since, with the exception of the unique leaching of chalcocite ores at Inspiration, flotation is still the exclusive mainstay for primary recovery of all base metal sulfides, the solution of these problems as they arise is vital to the well-being of the mining industry. Before considering the problems themselves, it will be useful to review the current status of sulfide flotation in the United States. The last comprehensive survey by the Bureau of Mines in 1975 (1) showed sulfide ore tonnages treated from 1960 to 1975 as summarized in Table 1; Table 2 gives similar data for the flotation of all non-sulfide ores. Noteworthy is the leveling off in sulfide ore tonnages in 1970-1975, with a probable further decline in the past three years, and the sharp drop in the number of plants floating sulfide ores. In contrast, the tonnages of non-sulfide ores floated, as well as the number of individual plants, has continued to increase. In spite of these trends, two-thirds of the total tonnage of the ores to which flotation is applied is still represented by sulfides. Average grades of sulfide ores in 1975 were: about 0.6 percent for copper; near 5 percent for lead; and near 3 percent for zinc. Recoveries averaged in the low 80's for copper; about 95 percent for

Jan 1, 1979

By Alphonse Hennin

It is well known that under certain conditions ammonia is found in the gas produced by the distillation of coal. Until recently it was held, and many still believe, that this ammonia exists in the coal, and is a natural product of the destructive distillation, varying in percentage, like the other products, according to the nature of the coal, but not formed synthetically beyond that limit. This opinion is in contradiction with well-established facts concerning the formation of ammonia from the elements of the coal. If any ammonia exists as such in the coal, the quantity is insignificant. The purpose of this paper is to explain the theory of the formation of ammonia during distillation, and call the attention of the members of the Institute to its application in connection with the production of heating-gas for metallurgical purposes, etc. For many years little or no importance was attached to the presence of ammonia in coal-gas. It was deemed by the gas-manufacturers an undesirable product of the process, as one of the impurities to be removed; and no attempt was made for its recovery. Not until its practical extraction and utilization was found possible, did scientists commence to investigate the question. Little was known about the nitrogen of the coal, and still less about the reactions leading to its transformation into ammonia. A. W. Hofmann, I believe, was the first to establish a relation between the percentage of nitrogen in the coal and the proportion of ammonia in the coal-gas. As early as 1863 he pointed out that, in dry distillation, such as is practiced in the manufacture of illuminating-gas, only one-third of the total nitrogen in the coal is liberated, two-thirds remaining in the coke. It is no longer possible to doubt that the ammonia is a synthetical product, resulting, under certain conditions, from the combination of the,elements of the coal. Chemistry teaches that ammonia is formed in many cases when

Jan 1, 1893

By C. F. Hardy, D. R. Mitchell

Bolts held up roofs as mining machines went on to set new records, but rising labor costs still plagued operators.

Jan 2, 1951

By Brian W. Mackenzie

In this age of advancing technology, mining companies are confronted with increasing competitive forces. The depletion of high-grade deposits and the development of substitute materials are intensifying market competition. The accelerating activity of petroleum companies in mineral exploration is increasing competition for deposits. At the same time, the trend in government policy is towards a reduction in traditional mineral-industry incentives. To succeed, the mining company must respond to these changing economic conditions by developing a decision-making framework that can effectively contend with the new opportunities and constraints. What are the elements of such a decision-making framework?

Jan 1, 1970

By R. W. Smith

An amine used as a collector in a commercial flotation process is usually a rather impure substance. The differences in ionization constants and solubilities of various amines undoubtedly affect their collecting power or strength. This investigation explores some of the differences among several amines of similar (although not precisely the same) chain lengths. An attempt is made to relate the differences to both observed contact angle and Hallimond tube flotation behavior in quartz systems.

Jan 1, 1974

Although the Suggestions to Institute Authors, as revised and amplified over the years to meet changing conditions and experience, have had as their primary objective the guidance of the author who is preparing a paper for record in the TRANSACTIONS, there are in this current version many excellent suggestions for the preparation of any material for publication by the Institute In this connection it should be emphasized that in a sense, and to a degree determined by the editors, the Institute has in its journals "a place for everything," especially a place for the article of practical nature that is of immediate but not necessarily permanent interest Such articles may be referred by the Institute Technical Publications Committee to the editors or submitted directly to them , [Papers (TECHNICAL PUBLICATIONS and TECHNICAL NOTES) authorized for the TRANSACTIONS are, with the discussion, gathered together at the end of the calendar year and with a table of contents and index, bound, according to Branch classification, as volumes of the TRANSACTIONS

Jan 1, 1952