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By Joseph W. Murray

Prior to 1950 Magma's ore production came from two parallel, steeply dipping, east-west striking mineralized faults, one called the Main or Magma vein and the other the Koerner vein, which lay about 1100 ft to the south. This vein system has been explored and mined over 9000 ft horizontally and 4800 ft vertically. In 1950 continued exploration led to the discovery and development of replacement orebodies in the Devonian limestone zones adjacent to the veins. These replacement deposits occur in the eastern part of the Magma mine and follow the strike and the 30º east dip of the host limestone. Strike length of the ore bodies varies from 250- 500 ft and thickness from 15-125 ft. The orebodies are large tabular masses with chalcopyrite and bornite being the dominant ore minerals. Hematite and pyrite are the most abundant gangue minerals. Incompetent limestone, shale, or a porphyry sill hanging wall is characteristic of portions of the replacement beds. In many instances the ore is blocky, badly fractured and intermixed with layers of limestone gouge, pyrite and hematite.

Jan 6, 1973

By John Ryan

SIR HUMPHREY DAVY'S epoch-making treatise delivered on Nov. 9, 1815, before the Philosophical Society of London, first announced and demon¬strated a flame safety lamp for detecting methane in mine air. Coal mining was known in England as early as 1180, more than 600 years before the advent of a safe lighting and gas-detecting appliance. Mining, no doubt, took place first in outcrop coal, and danger from gas did not become apparent until the workings became deeper and more extensive. Davy's lamp did much to increase the safety of miners, and a modified Davy lamp is still widely used for detecting the presence and approximate amount of combustible gas in mine air. No factor in coal mining has improved more rapidly during the past 15 years than safety measures. This progress came about not only as a result of the work-men's compensation laws now in force in most of the states of the Union, but because the research work of the U. S. Bureau of Mines has demonstrated some dan¬gers incident to coal mining which were not considered to be serious matters prior to that time. Electric power and explosives are necessary but 1-potential hazards in American coal mines. A general mechanization program is now under way, while the mines are growing deeper and more extensive. Conse-quently ventilation problems are more complex and a demand has been created for positive detecting devices for carbon monoxide as well as methane. Scientists and manufacturers, working hand in hand during the past 10 years, have invented and developed appliances which make systematic and effective examination of mine air possible. The object of this paper is to describe briefly the approved testing devices in use today, with the hope that they may lead to the saving of life. Dangerous coal mine gases may be placed in two groups: (1) those that are dangerous because of their explosive properties, and (2) those that are dangerous because of their toxic properties. Methane (CHI) is the important gas of the first group, and in so-called gaseous mines constantly exudes from the coal and rock; it may accumulate and form an explosive mixture.

Jan 2, 1927

By Harold Rose

THE peak of production from the Appalachian natural gas field was apparently reached about 10 years ago, and the annual production from Pennsylvania, West Virginia and Ohio has now dropped to about two-thirds of the amounts obtained in 1916 and 1917. This .falling off in production has occurred in spite of vigorous efforts and large expenditures by producing companies to maintain or increase their output. The greatly increased costs of development and handling are reflected in the present average value of natural gas at the point of consumption, which value in the three states referred to, has more than doubled in the past 10 years. While it is true that the natural gas production of the United States has increased during recent years, this increase has come from southwestern states, particularly from Oklahoma, California, Louisiana and Texas, which states are now leaders in the production of this valuable but fleeting resource. Pennsylvania, originally the leading state in natural gas production, occupies sixth place in the latest (1924) U. S. Bureau of Mines statistics. West Virginia, which held first place for 15 years, has dropped to third rank, and Ohio is the seventh state in the order of natural gas production. Domestic and industrial demands for gas are constantly increasing everywhere in the United States. These growing demands have accentuated the difficulties in the localities with depleted natural gas supplies, and serious shortages have already occurred during winter months in the Pittsburgh district. Some relief has been obtained by placing restrictions on the industrial use of natural gas, and by increasing the price (which tends to reduce consumption). Yet these are but temporary expedients for checking gas consumption, which fail to solve the problem of adequate future supplies of gas.

Jan 10, 1926

By Donald E. Crowell

In the fall of 1969, ASARCO and Newmont Mining Co. began the design of the 700tpd concentrator at their Black Cloud shaft located near Leadville, Colo. The concentractor would treat by flotation a Pb-Zn-Ag ore containing minor gold values. Flowsheet design was based on laboratory test work performed at the Minerals Research Testing Laboratory of ASARCO. Since the concentrator is located at an elevation of 11,000 ft, cold weather was a major factor in design considerations. The original capacity was designed as 700 tpd but for various reasons an ultimate capacity of 1,000 tpd was desired. This necessitated special consideration in the design of several areas, particularly the grinding circuit. The grinding circuit chosen was a single 9 X 12 ball mill operating in closed circuit with one 20-in. cyclone. The ball mill will operate at low speed and as an overflow type originally. The mill can be speeded up and converted to grate type for handling the larger tonnage when required. Thickeners and filters were oversized and space was left for additional flotation cells in order to handle the increased tonnage in these areas. Pumps were sized so that they could handle the increased tonnage by increasing their speed. Construction began in May 1970; the Black Cloud concentrator went on-stream in April 1791.

Jan 1, 1974

By J. Donald Graham, John G. Kuhn

The goal of any development drilling program is the drilling of the exact number of holes necessary to adequately determine grade and dimensions of an ore body, no more and no less. Any technique which eliminates unnecessary drilling costs produces beneficial results, both to the company and to the person who can claim the savings. The method for controlling development drilling programs to be described was developed during the latter part of a major development drilling project at the Christmas mine of Inspiration Consolidated Copper Co. in Gila County, Arizona. It was used to test the need for drilling individual holes but could be expanded to control an entire project. Application of this method involves an evaluation of geological conditions present and a good bit of common sense. Projects involving large disseminated, rather homogeneous ore bodies of the porphyry-copper type would be the most likely candidates for application of the technique. Discontinuous ore bodies would not be amenable. The method is based on the measurement of the linear correlation between the spatial distribution of two sets

Jan 1, 1973

Jan 1, 1966

By A. E. Gorum, I. Cornet

Fatigrle of ionic crystals has been studied primarily in magnesinm oxide. under cyclic stress dislocations move irrreversibly; they multiply; slip bands form and grow; cracks mucleate and propagnte, and failure occurs. The use of ionic crystals such as MgO is advantageorus in such investigations because they are optically transparent. Individual dislocation Intersections with {100} surfaces may be observed with a standard microscope, using etch-pit techniques. Slip, deformation, crack .formation, and fracture in MgO crystals under cyclic stress are compared with cotrresponditzg processes in metals. ThE effect of cyclic loading in metals has been studied for many years. The appearance of slip lines is readily observed and the ensuing fracture may also be seen. From these observations it is possible to predict the behavior of a material and make an educated guess as to what is happening internally, but the actual changes taking place within the structure are not readily apparent. If one could obtain a material in which the individual glide components could be observed, it would be invaluable in determining the actual slip distribution resulting from cyclic loading as well as the distribution of slip in the neighborhood of a growing crack. Such a material is magnesium oxide. Dislocation arrays may be observed by means of etch pits

Jan 1, 1961

By Samuel M. Cassidy

The exact date of man's first use of coal is lost in antiquity. The discovery that certain black rock would burn was undoubtedly accidental and probably occurred independently and many times in the world over thousands of years. It is quite likely that these independent discoveries were made when primitive man chanced to build camp fires on exposed ledges of a black rock, then was amazed when it caught fire. The Chinese recorded the use of coal 1100 years before the Christian Era and from the Bible we learn that King Solomon was familiar with coal in what is now Syria. In Wales, there is evidence that the Bronze Age people used coal for funeral pyres, and it is known that the Romans used this fuel. There are other ancient references. So the knowledge that coal would burn, and even some uses of that knowledge, go back thousands of years. However, practical and consistent use of coal seems to date to England in the Middle Ages. COAL IN AMERICA In the Americas, there is evidence here and there of occasional use by the Indians. However, the first recorded discovery of coal, in what is now the US, was by French explorers, who reported an outcrop exposure on the Illinois River in 1679. Following this, other discoveries were made by French and British explorers, but the first recorded actual usage was in Virginia in 1702, where a French settler was granted permission to use coal for his forge. Earliest recorded commercial mining was in 1750, from the James River coalfield near Richmond, VA, a deposit now abandoned. Besides local consumption from this field, shipments were made to Philadelphia, New York, and Boston. During the Revolution this coal was of importance in the manufacture of shot and shell; so important, in fact, that the British sent an expedition in 1781 to destroy the iron works and

Jan 1, 1981

By P. N. Ivanov

The world experience shows that the tremendous potentialities of the computers and other technical means in improving management efficiency are not fully utilized. One of the causes is the tendency to solve the problems of management automation divorced from the management methods and schemes which demand continuous improvement in view of the steady progress of the social production. It may be safely affirmed that making decisions on management improvement divorced from management schemes or on both divorced from management automation problems cannot lead to success. The grave and sometimes unsuperable difficulties encountered in management automation arise from copying traditional management methods and schemes without solving the problems which exist both in management and automation fields. The system solution of management problems has unquestionable advantages and is not proposed for discussion. What is proposed to discuss is the difficulties emerging in developing a methodology of the system approach to management improvement and automation. Though aware of the fact that the questions proposed for discussion are not new, we think it advisable to briefly review them, first because they fall in the "chronically unsolvable" category, and, secondly, as it will enable us to illustrate the method of solving them in the framework of the proposed system approach.

Jan 1, 1977

By K. H. Nimerick, G. P. Laflin

Laboratory data and field tests indicate that substantial losses of valuable coal can be caused by wind erosion. Wind tunnel tests show the effects of wind velocity and particle sizing on the amount of coal lost while in transit. Different coals were evaluated to determine the variables associated with wind erosion. The erosion losses can be substantially reduced by using a binder, or crusting agent, to consolidate the surfaces of the coal into a solid mass which resists erosion. This not only reduces economic loss but minimizes polllution.

Jan 1, 1980

By R. E. Head

SOME mixtures of sulphide and oxide ores from the Tintic district in Utah are of a sufficiently good grade to be shipped to the smelter without beneficiation. In mining this type of ore, however, a material tonnage of ore of a similar composition but of lower grade is obtained. It is a ques-tion of economics whether such ore should be shipped with a certainty of a small return or concentrated if that would yield a sufficiently increased return to amortize plant construction and upkeep and yield a higher rate of profit than at present. It may be assumed that the tonnage of this borderline ore is constantly increasing and that eventually it will, attain such proportions as to justify plans for milling on a relatively large scale. Under existing conditions, the producer of mixed sulphide and oxide ores is not greatly concerned about the physical characteristics of his ore or of its mineralogical complexities, since his contract with the smelter calls for payment on the basis of chemical analysis. When concentration is contemplated an entirely different picture is presented. Percentages of valuable metal content must then be con-sidered in terms of minerals, for it is in the form of minerals that recoveries are made and losses sustained. In describing the performance of a given flotation mill and reagent combination, it may be stated as a generality that a specific percentage recovery of valuable elements is made. Tech-nically, however, the concentrator is really constructed and the reagents are selected to recover the valuable minerals. These considerations must be given prominence in discussing border-line ores from the Tintic district because of their physical characteristics and mineralogical composition. Because of these peculiarities they may be justly termed complex, since their lead, silver, and copper contents are each represented by two or more minerals of different chemical composi-tion and presenting widely divergent physical properties. This paper sets forth the results of a microscopic study of a type of borderline ore from the Tintic district that is now being treated by direct smelting. A

Jan 1, 1938

By P. G. Mason

The upswing in the price of gold in 1979 prompted renewed interest in the Mercur gold property by Getty Oil Company, owner and operator, and Gold Standard Inc. of Salt Lake City, Utah, currently retaining a 15% net profits interest. Extensive geological exploration work resumed to delineate the ore reserves, and metallurgical test work was initiated under the direction of A.H. Ross & Associates. This led to the development of an aqueous pressure oxidation process suitable for treatment of the refractory ores. Subsequent geostatistical studies revealed that the distribution of high refractory ore was less than previously estimated, and thus a higher return on investment could be realized if a direct carbon-in-leach process were used despite a sacrifice in overall recovery. This paper reviews the geological and metallurgical studies that led to this final process selection.

Jan 1, 1984

By Toyohiko Hirota, Fukuo Itoh

Oil and natural gas aside, sea floor mineral resources currently being exploited in Japan are offshore sand and gravel and deep-sea manganese nodules. The mining of sand and gravel has already started. With regard to manganese nodules, the geophysical investigation and the study of the mining method are also underway. This report outlines the activity of a few Japanese firms, the Deep Ocean Minerals Association formed by some 30 private firms, Government agencies, a public corporation and two government research institutes. Researches on new exploration instruments, properties of deep-sea sediments and the mining method currently conducted by the National Research Institute for Pollution and Resources are described in detail.

Jan 1, 1976

By T. L. Kesler

With only six small spodumene prospect pits, no detailed mapping, and no subsurface information in 1938, the Carolina lithium-pegmatite area now contains four mines among more than 25 properties on which exploratory work has been done. Even the open pit mine of Foote Mineral Co. described herein, from which ten million tons of ore and waste have been removed since 1952, was virgin ground when mapped in 1938-40 1. It has been a privilege to participate in the transition. In 1940, the spodumene pegmatites were known in a 25-mile belt (originally noted for tin prospecting) between Lincolnton, N. C. and Grover at the South Carolina line. Subsequently, Broadhurst 2 reported relatively small bodies northeast of Lincolnton near the Catawba County line. To the south, diamond drilling done in 1953 on the old Ross tin-mine property near Gaffney yielded pegmatite cores containing a few crystals of spodumene. This fact, not previously reported, suggests that some of the pyroxene in the Ross shaft as described by Sloan 3 may be spodumene.

Jan 9, 1961

By D. H. Henley, F. F. Craig, W. W. Owens

The oil recovery performance of systems producing entirely by bottom-water encroachment has been experimentally determined in a series of scaled laboratory-model tests. The effects of well spacing, fluid mobilities, rate of production, capillary and gravity forces, well penetration and well completion techniques on the oil recovery performance have been investigated. The laboratory tests were performed using two uniform, un-consolidated sand-pack models. The models have ratios of the interwell distance to the formation thickness of 12 and 2, respectively. Tests at constant total fluid production rate were performed simulating a range of uniform reservoir characteristics and operating conditions encountered in field operations. The performance was determined by material balance and by observation of the encroachment of dyed fluids into the models. The results of the model tests agreed with those obtained mathematically when the conditions previously considered in theoretical studies were simulated, that is, when the oil and water are of equal density and no capillary forces exist. The model study of bottom-water drive indicated that certain variables can aoect the oil recovery performance to a greater degree than can be predicted by present analytical methods. In one comparison, the oil recovery at a water-oil ratio of 20 (obtained at a wide well spacing) varied as much as threefold, depending upon the system's properties and the production rate. Lesser effect of mobility ratio and no eflect of capillary forces over the range studied were observed. The test 'results also showed that the deeper the well penetration into the oil column, the greater the total water production to a producing WOR of 20. However, the ultimate sweep efficiency, and so the oil recovery to this level of WOR, did not vary significantly with well penetration. Horizontal fractures at the top of the formation did not significantly change the sweep characteristics of the reservoir models when values of radius and fracture capacity encountered in actual reservoirs were used. Impermeable pancakes at the bottom of the well moderately increased the oil recovery efficiency both at water breakthrough and at high water-oil ratios. A method is outlined by which the oil recovery performance of other uniform bottom-water drive systems can be estimated from the information obtained in these model tests. INTRODUCTION When oil is produced from a well which partially penetrates an oil zone completely underlain by water, the water rises directly beneath the well in a symmetrical cone when the system is uniform. Two different flow mechanisms can cause the water cone to form—coning and bottom-water drive. In coning, the aquifer is relatively inactive and the cone is formed beneath the well by the pressure gradients associated with the oil flow to the well. The oil can be produced by a solution-gas drive, an edge-water drive or other driving forces in the interwell area. In a bottom-water drive, the driving force for oil production comes from an upward encroachment of the underlying active aquifer. Two papers have analyzed the theoretical performance characteristics of bottom-water drive reservoirs. In the initial mathematical investigation, Muskat' established the equations which determine the pressure distribution in this type of reservoir and solved these equations for certain conditions. Specifically, it was assumed that the water and oil had equal mobilities and equal densities, there were no capillary forces, the pressure throughout the oil zone remained above the bubble-point pressure, a constant pressure existed at the initial water-oil contact and the oil was completely displaced by the encroaching water. These assumptions were used in obtaining analytical solutions. In general, Muskat found that the sweep efficiency to initial water breakthrough to the well was larger for the thicker oil zones, the closer well spacings, the lower ratios of vertical to horizontal permeabilities, the smaller the penetration of the well into the oil zone and the smaller the bore size of the well. The production history after water breakthrough was expressed as a volumetric sweep efficiency at a given producing water-oil ratio. The results indicated that cumulative oil production at producing water-oil ratios of 10 is less affected by the well spacing than is the water-free production history. Muskat studied well spacing which today would be regarded as close. The maximum value of his dimensionless well spacing (ratio of interwell distance to formation thickness) was 4.3. This would require the development of a 50-ft-thick oil sand on less than 10-acre spacing if the vertical and horizontal permeabilities were equal, with

By J. B. Evans

Maintaining overall optimum profitability at a mine site necessitates constant reassessment of operating strategies. In essence, each strategy is a particular combination of envisaged capital expenditure, income flow and elapsed time. Selecting a strategy, based on profita¬bility potential requires each contemplated strategy being subjected to discounted cash flow analysis; even with a computer such analysis can be cumbersome. The chapter discusses a 'shortcut' technique which assigns profitability rankings to alternate strategies and iden¬tifies those aspects of a. strategy which impact heavily on profitabil¬ity. This technique can yield quick assessments of sufficient accuracy for many operating strategy decisions. taken on site at on-going mines.

Jan 1, 1978

By R. Jr. Schuhmann

PROBLEMS in expressing, interpreting, and using size-distribution data recur in many phases of mineral dressing; therefore it is desirable that size analyses be ex-pressed in such a form, either numerically or graphically, that comparisons can be made readily. The size distribution of comminuted material is a result of a specific physical operation on the material and therefore should be governed by some definite physical principle, or cause-effect relation. Although this principle has not been dis-covered, it has been found that the size distribution of comminuted, homogeneous solids may be expressed by relatively simple mathematical equations. Two equa-tions in particular, proposed by Gaudin1 and by Rosin and Rammler,2 respectively, have stood out, both having wide demon-strated ranges of application. The form and the method of application of the two appear almost irreconcilably different on the surface, but, as will be shown, they are asymptotic in the fine sizes when expressed in the same units. This paper gives the results of a further study of the Gaudin and Rosin-Rammler relations, made with the object of develop-ing a form of size-distribution equation that will be more usable and more signifi-cant-particularly in comminution studies, both for interpreting the nature of size distribution and for evaluating surface. The work is summarized in the following:

Jan 1, 1940

By R. S. Archibald

The subject of this paper is particularly appropriate, since Daniel C. Jackling was active in early exploitation of taconites on the Mesabi Range and contributed greatly to their later economic development. After his success in developing the low grade porphyries in the West he looked for more worlds to conquer, and so undertook the concentration of low grade taconites, from which he hoped to produce commercial ore. Mesabi Iron Co., organized in 1919, actually did produce merchantable sinter from taconites in 1922. The enterprise did not prove commercial at the time, as cost of production was high and the surplus of iron ore in the Lake Superior District already contributed to a low market price, but this same property has since been developed by Reserve Mining Co. The work done by Jackling had much to do with the success of this later venture. Iron ore was first discovered on the Marquette Range in Michigan in 1845. The first ore from this range came from the old Jackson mine in Negaunee in 1848. During these early years this property and others on the Marquette produced limited tonnages for transportation to Lower Lakes and for consumption by charcoal furnaces in the area, where a plentiful supply of hardwoods furnished the charcoal for iron smelting. The Marquette and other ranges tributary to Lake Superior did not produce much ore for transportation to Lower Lakes until the locks at Sault Ste. Marie were constructed, but from the time the first lock at the "Soo" was completed in 1855 these ores were transported through the locks to consumer centers in the East. The Marquette Range has a history of continuous production from 1848 to the present day.

Jan 5, 1959

By J. H., R. W. Guard, Westbrook

In 1953 Kornilov and Mints' presented data on thermal expansion and electrical conductivity of the compound Ni3A1 which indicated the possibility of a transformation in Ni3A1 at about 600°C. The present paper gives results of some observations

Jan 1, 1960

By W. Joseph Schlitt, Kenneth J. Richards, John D. Prater

Kennecott Minerals Company has developed a leach-hydrolysis route for treating flue dusts from copper smelters The flue dusts are acid leached in an oxygen atmosphere to solubilize copper and fix the arsenic, antimony, and bismuth as stable compounds Copper is recovered by cementation with Iron and the barren solution is recycled Molybdenum and other values may be recovered by modification of the basic flow sheet Results of bench scale and pilot plant tests are discussed in terms of the effect of operating parameters.

Jan 1, 1981