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By W. B. Boggs, J. N. Anderson

An account of the operation of the Noranda smelter covering the period from December, 1927, when the smelter started, until December, 1929, was given in a paper published by the Canadian Institute of Mining and Metallurgy early in 1930.' The object of the present paper is to review matters of interest in the original paper and to describe the present construction and operation of the smelter, with particular reference to the reverberatory-furnace practice. The Noranda smelter was built by Noranda Mines, Ltd., from the designs of A. E. Wheeler, consulting metallurgist of New York, for the reduction of ores and concentrates from the Horne mine and to treat, on a custom basis, ores and concentrates from other mines in the Rouyn district. The smelter is at Noranda, about 330 miles directly north of Toronto. Construction work was started in June, 1926, and copper was first produced in December, 1927. The smelter was built throughout as two duplicate units, each with a rated capacity of 500 tons of ore per day. Operations were started with one unit and after several months it was found that one unit alone could smelt 1000 tons of ore a day. At that time there was only one hoisting shaft, No. 3, and its hoisting capacity and the capacity of the original crushing plant were insufficient to supply ore for the two units at the increased tonnage. Accordingly No. 4 shaft was sunk and a new crushing plant provided to handle the ore hoisted there. Operating two units at capacity also required the installation of two more converters to treat the additional quantity of matte produced. This work was completed in the latter part of November, 1929, and since then both smelter units have been operating continuously. In 1928, a mill to treat 500 tons a day of concentrating ore was completed. Since then the concentrator capacity has been increased twice, and at present 2000 tons a day of ore are being concentrated. The layout of the surface plant of the mine, concentrator and smelter is shown in Fig. 1 and the general plan in Fig. 2. The smelter is shown in more detail in Fig. 3. The original hoisting shaft, No. 3, is now used only for handling men, supplies and waste rock, and the original crushing

Jan 1, 1934

Jan 1, 1966

By Dr. O’Neil Thomas J., Donald W. Gentry

"We can easily represent things as we wish them to be..” -Aesop INTRODUCTION The first eight chapters of this book have primarily addressed the concepts and fundamentals associated with project valuation, particularly as they apply to mining-related projects. Specific emphasis was placed on the engineering and economic parameters and estimates necessary for quantifying line items in pro forma income statements and the subsequent calculation of net annual cash flows. Given these estimates of relative benefits, costs, and annual cash flows for a project, it then becomes necessary to convert these estimates into measures of relative desirability or attractiveness. The criteria and techniques typically utilized to determine project acceptability or desirability are, then, the topics of discussion in this chapter. Before proceeding it may be advantageous to put the problem of project evaluation into proper perspective by reiterating some of the fundamental concepts developed in Chapter 1. The basic premise set forth in this book is that the objective of the firm should be to maximize its value to its owners (stockholders' wealth). This value or wealth is represented by the market price of the firm's common stock; consequently, the primary objective of the firm can be restated as one of maximizing the value (price) of the firm's common stock in the marketplace over the long term. This price, in effect, is an indicator or index of the market's perception of the company's progress and a reflection of the investment, financing, and dividend decisions made by corporate management. These three major decisions are inter- related and jointly impact the market price of the firm's stock. Therefore, if the objective of maximizing the value of the firm to its stockholders is to be achieved, an optimal combination of the three decisions will be necessary. It is important to emphasize that maximizing stockholder wealth is not the same as profit maximization or even the maximization of earnings per share. Corporate managers making decisions based on the objectives of maximizing profits and/or earnings per share must recognize that these objectives do not consider: (I) the timing or duration of expected returns, (2) the business and financial risks of the promised earnings, or (3) the dividend policy of the firm. Obviously all of these factors are of concern to the company's stockholders and will have an effect on the market value or price of the firm's common stock. Maximizing market price per share, or wealth maximization, is therefore the appropriate corporate objective and

Jan 1, 1984

By F. C. Sturges

FOR some time mining engineers have been interested in the possibility of using small diameter shafts, sunk by core drilling, as aids to ventilation and as emergency escapeways. The possibilities are interesting to contemplate, but new methods involve unknowns, and interest tends to remain passive until these unknowns are solved. Recently we have completed two 36-in. diam. core drilled shafts, and wish to make the data on these available to the industry. Both shafts were drilled for the McLain Fire Brick Co., one at its Buckeye mine and the other at its Colonial mine. Both mines are in the fireclay underlying the Lower Kittanning coal. Both mines have been in operation for a number of years [ ] and have required expensive maintenance work on return airways. It was decided that considerable savings could be effected by short-circuiting the air to the surface through small shafts. It was also realized that these holes, located near the present workings, would be of added value as emergency escapeways. Originally, 48-in. diam. shafts were considered, but actual computations showed 36-in. diam. shafts were more than ample at both mines. The shaft at the Buckeye mine is 240 ft deep, and that at the Colonial mine 258 ft deep. Both holes were started in the lower part of the Conemaugh formation and penetrated Conemaugh and Allegheny strata. The holes were started through the unconsolidated materials overlying bedrock by constructing a concrete collar with a wall thickness of 8 in. Then the shafts were drilled by the shot-core drill method. An annular groove was cut in the rock by the abrading action of chilled steel shot run under the shoe of the core barrel. The drilling was done in stages, the core barrel drilling the groove for a certain distance depending on conditions encountered, and then the cores broken off and taken out in sections. The core barrel had a 36-in. o.d. and the finished diameter of the shaft measured almost 37 in. The major questions that could not be answered until the completion of the first shaft were, (I) how much ground water would be encountered, how would it hinder the drilling, and how difficult would it be to seal off, and, (2) how would the walls of the hole stand up. The holes of course could be cased or lined, but that is considerable added expense in any shaft.

Jan 1, 1947

By P. R. Schmidt, N. J. Themelis

A study zvas made of the deoxidation of copper at 1170°C by injecting a jet of carbon monoxide vertically upwards into the melt. The effects of submersion depth (2 to 20 cm), orifice diameter (& to 5 in.), and gas velocity (100 to 3650 ft per sec) were examined. In the oxygen range 0.1 to 1.0 pct 0, the overall rate was conlrolled by gaseoLcs mass Lransfer. The results were interpreted in terms of a rate coefficient per unit depth which was found to be constant with distance along the jet axis and nearly proportional to the orifice Reynolds number in the range 1000 < NReo < 9100. AS the gas flow rate through an orifice submerged in a liquid is progressively increased, at least three regions of bubble formation may be distinguished. At very low rates, the formation of bubbles is practically a static phenomenon, depending on the orifice diameter, the liquid surface tension, and the densities of the two phases. In this region, the bubble size is constant while the frequency of bubble formation increases with gas flow rate.&apos;-3 At higher flows (500 < NR~, < 2100), the frequency of bubble formation reaches a steady value and the bubble size increases with gas flow rate; when the bubbles issuing from the orifice become so large that they start coalescing to form larger bubbles, the turbulence induced in the liquid by the passage of previous bubbles shatters them into small bubbles of varying size. Finally, for gas velocities in the intermediate and turbulent regions of flow (NR,, > 2100) a tangential separation surface is created around the jet and momentum transfer takes place between it and the surrounding liquid medium. The entrainment of liquid and the resulting deceleration of the gas-liquid dispersion causes the jet to expand forming a characteristic jet cone. The large velocity and density differences between the jet and the liquid result in a high degree of instability and the jet envelope fluctuates rapidly.The characteristic jet cone can be observed by means of time exposure photographs such as those shown in Fig. 1 for an air jet introduced vertically upwards in a water bath. High-speed photography has showns that the gas-liquid dispersion within the cone consists of small bubbles the size of which depends mainly on the jet orifice diameter and Reynolds number. In the laminar region of flow, the following correlation was obtained by Leibson: The results of Liebson et a1.&apos; are plotted in Fig. 2. It can be seen that the region 2000 < NReo c 10,000 is not well-defined experimentally. In the entrance to the fully turbulent region of flow (NR,, = 10,000), the mean bubble diameter decreased to about 0.4 cm and varied only slightly from there on according to the correlation:

Jan 1, 1968

By Frederick F. Sharpless

The term "segregation," as here used, means the separation of certain natural resources into groups, consisting of one or more members, with the idea that when thus segregated, each group may be more easily and effectively administrated. We may, for example, consider surface rights as distinct from underground rights, and stop there; or we may go further, and deal separately with timber, water, and agricultural rights, or, going underground, we might deal separately with such groups as precious and base metals, clay, oil, gas, etc. The present paper contemplates only the separation so far as practicable, for administrative purposes, of surface from mineral rights. " Classification," in this paper, has reference to the groups into which the government has divided, is dividing, or will hereafter divide its natural resources; first, into the broad classes of mineral and agricultural lands; and, second, into coal, oil, phosphate, brine lands, etc., the central idea being the separation into natural groups for the purpose of simplifying administration and for the purpose of encouraging maximum development and minimum waste. The two subjects are in some respects quite distinct, but as my argument develops, I think it will be obvious why they are discussed in the same paper. In the pursuit of our professions as mining engineers, geologists, or operators, we are continually confronted by conditions with which our present mining laws or regulations are incompatible. It may be a conflict, hardship or injustice, a piece of favoritism, or of unnecessary red tape; or we may see lack of development in a promising locality, and wonder what is the reason. Often we can see where a modification, slight or radical, in the laws would have obviated the difficulty without doing harm to any of those immediately concerned. Such alterations as individuals could intelligently suggest would be based on a relatively small number of situations occurring in their experiences. The published replies to the queries formulated by the various committees on mining law appear generally to reflect personal experience. Concerning a few points, there is a marked uniforhity of opinion, while on other points opinions

Jan 1, 1915

By A. H. Geisler, J. H. Keeler

Preferred orientations in rolled and annealed titanium sheets were determined by the Geiger counter spectrometer X-ray diffraction technique. Five annealing textures dependent upon the temperature range of annealing were found, and in order of increasing annealing temperature pendent upon the temperature range are: 1—a deformation like texture, 2—a rotated inorder a-recrystallization temperature texture, 3-a retained u-recrysraIlization texture, on annealing at lower temperatures of the ß-region, 4—a transformation texture based on recrystallized a and predicted by the Burgers&apos; relationship, and 5—a ,ß-cube texture. These results are examined in terms of current theories of recrystallization textures. UMEROUS investigators have described the tex- ture obtained by cold rolling the hexagonal metals, titanium, zirconium, and beryllium, which have c/a ratios less than that of ideal packing, 1.633. The basal planes are rotated out of the rolling plane, about the rolling direction, so that the basal poles are tilted toward the transverse direction as shown schematically in Fig. la. In all instances but one,&apos; it was also reported that the [1010] direction was parallel to the rolling direction (see Fig. lb). Hot rolling has been reported as causing a similar tilt of the basal poles in the transverse direction (see Fig. la) and causing the [1010] direction also to be parallel to the rolling direction as shown schematically in Fig. lb. Annealing after deformation does not appreciably change the tilt of the basal poles in the transverse direction." Beryllium2-7 continues to have the [1010] direction in the rolling direction after annealing, and similar observations for titanium and zirconium&apos; . have been reported for annealing at fairly low temperatures, again as in Fig. lb. At higher annealing temperatures, however, the recrystallized grains of titanium" and zirconium have an orientation such that the [1120] direction is approximately in the rolling direction, although the basal poles are still inclined in the transverse direction. Figs. la and lc show the resulting orientations schematically. This change in orientation has been described as a nominally ±30° rotation of the hexagonal crystallites about the basal poles of the cold rolled texture and is apparent from the results which are summarized in Table I for investigations with the X-ray diffraction technique employing film. The angles y, , and ß are indicated in Fig. 2 which represents the stereographic projection of (1070) poles for the mean orientation of a pole figure. Texture determinations for titanium using the Geiger counter spectrometer have provided similar results except that in some instances additional components of the texture were proposed, as shown by the summary of data in the upper half of Table 11. On the other hand, the spectrometer technique, when applied to zirconium,* has revealed a splitting Recently completed studies of the textures of annealed zirconium", show zirconium to possess textures very similar to those reported here for titanium. Therefore, much of this discussion will include zirconium by virtue of its close similarity to titanium in pref erred orientations. of the intense areas of the pole figure for samples annealed at 600°C. This splitting could be described by a 7" rotation of the tilt axis about the normal to the rolling plane. Such a splitting for the annealed texture relative to the cold rolled texture was not observed in other determinations for either zirconium or titanium using the less sensitive film X-ray methoe and makes the relationship between the two types of texture more complex than the simple rotation about the (0001) pole based on film work. The more precise investigations on zirconium permit the descriptions in the lower part of Table 11, which show that the texture depends quantitatively on the temperature of annealing. When zirconium is annealed at temperatures up to 400°C, the texture is similar to the cold rolled texture, while annealing in the range 500" to 900°C produces a texture which is only approximately described as [11%] in the rolling direction. More precisely described results for zirconium show that the two types of splitting ( 1—about an axis in the rolling plane through an angle given in the second column in Table II and 2—about the normal to the rolling plane through an angle given in the third column of Table 11) depend on annealing temperature. The [1120 is the rolling direction only when the annealing temperature is in the vicinity of 900°C

Jan 1, 1957

By George Enos

As the coating formed affects the corrosion rate, duplicate samples of eight non-ferrous alloys were placed in flowing mine water. The alloys tested were as-cast or as-rolled and machined or polished. The paper describes the tests and gives the corrosion losses and the appearance of the samples at the end of the test. AN IMPORTANT factor affecting the rate and nature of corrosion of metals and alloys is the film, or coating, formed on the surface; and this may accelerate or retard corrosive action once started. The formation of films and coatings is intimately associated with the chemical composition and physical constitution of both the metal and the corroding medium. A film or coating may be either the corrosion product resulting from oxidation; that is, an oxide or salt, or a deposition of suspended matter from the corroding media upon the surface of the metal, or a mixture of both. The coating may adhere tightly or loosely to the surface of the corroded metal. In short, a film or coating is the reaction product of the corroding medium and the metal, which adheres to the surface of the metal and with which may be intermingled material from the attacking media not concerned in the chemical reactions. As the, terms film and coating are used by different writers for very different things, distinction is made between the two, by the present writers, on the basis of thickness. Thus, a film is defined as a corrosion product or deposition, on the surface of a corroded metal, that is of such thickness that it cannot be measured by the metallurgical microscope. A coating, on the other hand, is of such thickness that it can be measured. If the resolving power of the 2 mm. (equivalent focal length) apochromatic oil immersion objective (N.A. 1.4) is taken as the limit of the microscope, the limiting resolution is two lines that are 0.0002-0.0004 mm. apart. It is thus possible to measure coatings that are greater than 0.0002-0.0004 mm. thick. This thickness is equivalent to 200,000-

Jan 7, 1924

By D. R. Semmes

The possible oil territory of Alabama can be readily divided into two regions, the Paleozoic area of the north, and the Coastal Plain province of Cretaceous and younger formations lying to the south. This latter area has received much attention in the last few years and has been described by a number of writers.&apos; Although the possibilities of the Cretaceous series have been much emphasized by recent writers, the fact remains that the two, or possibly three, localities where oil or gas have been found in anything like paying quantities are confined to the area of Carboniferous rocks. Moreover, almost all of the oil seeps and a good percentage of the gas seeps are confined to this area.2 Topographically, as well as structurally, the Paleozoic area can be divided into three rather well defined provinces: (1) The broad, open Coosa Valley lying adjacent to the crystalline oldland, with comparatively little relief, except for occasional longitudinal ridges and rather intense folding; (2) the plateau region of horizontal or gently warped Pennsylvanian strata broken by occasional anticlinal valleys aligned northeast and southwest, outliers of the Coosa Valley proper, in which the older Paleozoic formations are exposed—a region of much relief (200

Jan 1, 1921

By J. R. Thoenek S. L. Windes

The amplitudes and frequencies of vibratiolls of a four-story stucco building were measured by specially developed electrocapacitive seismometers. Records were made on three floor levels with as many as 10 seismometers recording simultancously. Sources of vibration were: (1) an electric motor with unbalanced pulley, maximum speed 1800 r.p.m., maximum centrifugal force 90 lb., (2) truck traffic (both solid and pneumatic tires) moving over inequalities in the street in front of the house, (3) falling weights dropped on the street pavement from different heights, (4) miscellaneous sources, including a man jumping on the floor of the house and slamming doors. Tests were made to determine the natural frequencies of floor and wall panels by varying the speed of the unbalanced motor and by exciting the panels with a single impulse. The vibrations recorded were compared to records of vibrations from quarry blasts and it was observed that the vibrations from truck traffic were comparable to those recorded from quarry blasts and in no instance was there any damage to the building. As the tests were all of a negative character as far as damage was concerned, no index of destruction is formulated. Instead, the records are presented simply as vibration measurements obtained in an ordinary house under typical conditions.

Jan 1, 1940

By J. R. Thoenek S. L. Windes

The amplitudes and frequencies of vibratiolls of a four-story stucco building were measured by specially developed electrocapacitive seismometers. Records were made on three floor levels with as many as 10 seismometers recording simultancously. Sources of vibration were: (1) an electric motor with unbalanced pulley, maximum speed 1800 r.p.m., maximum centrifugal force 90 lb., (2) truck traffic (both solid and pneumatic tires) moving over inequalities in the street in front of the house, (3) falling weights dropped on the street pavement from different heights, (4) miscellaneous sources, including a man jumping on the floor of the house and slamming doors. Tests were made to determine the natural frequencies of floor and wall panels by varying the speed of the unbalanced motor and by exciting the panels with a single impulse. The vibrations recorded were compared to records of vibrations from quarry blasts and it was observed that the vibrations from truck traffic were comparable to those recorded from quarry blasts and in no instance was there any damage to the building. As the tests were all of a negative character as far as damage was concerned, no index of destruction is formulated. Instead, the records are presented simply as vibration measurements obtained in an ordinary house under typical conditions.

Jan 1, 1940

By J. F. Lewis

Believing that one of the essential points in mining, as in all other business, is to know the expense incurred in each particular department, I have carefully kept an account with each department for the past three years; and, as it may be of interest to some of our members, I herewith present it to the Institute, reduced to per centages of the total yearly expense, showing the cost for materials, repairs, expenses, tools, team accounts, powder, oil, and fuel, also for labor under its several heads: 1875—Materials. 1875—Labor, Repairs,...040 Expenses,....016 Team,. .. .. .017 Machinery,. .. .055 Tools,..006 Repairs,. .. .027 Improvements,.....030 Washer,. .. .076 Oil ..008 Pit,.. 178 Powder,..,043 Dirt,.. 130 Fuel,. .325 Superintendence,. ..050 .485 .516 100.1 1876—-Materials. 1876-Labor. Repairs,. . • .. .043 Expenses,......012 Team,.011 Machinery,. .. .090 Tools,..005 Repairs,... 027 Improvements,.....007 Washer,. .. .085 I,. ...,015 Pit,.. 139 Powder,. .. .. .030 Dirt,.. 160 Fuel,...321 Superintendence,. ..078 .444 .559 100.3 1877—Materials. 1877—Labor. Repairs,......102 Expenses,......019 Team,..031 Machinery,. .. .050 Tools,..030 Rrpairs,. .. .046 Improvements,....,031 Washer,. .. .057 I,...009 Pit,.....179 Powder,...035 Dirt,.. 162 Fuel,...200 Superintendence,. ..054 .457 .548 100.5 Average for the three years 1875, &apos;76, and &apos;77. Materials. Labor. Repairs,...062 Expenses,...016 Team,..016 Machinery,. .. .065

Jan 1, 1879

By Francis Cameron

Mining is both exciting and rewarding-although at times somewhat frustrating-and we all can have real pride in our industry, in its people, and in its accomplishments. It is, however, with concern that I have noted a deterioration in this Country in what might be called mining&apos;s stature and in the growth of a belief in many quarters that our mineral reserves are rapidly approaching exhaustion. In other words, there is a popular image that we are fast becoming a "have not" nation in many respects and that the domestic mining industry can no longer be considered, in the vernacular of Wall Street, to offer much in the way of "growth potential." I do not subscribe to this hypothesis, nor do I believe that the record of the mining industry bears this out. However, let me add that we can, in time, talk ourselves into this frame of mind and we can hasten the day when this very well might come about by unnecessary and unwise legislation or regulation. My remarks today are basically designed to give my reasons for refuting this negative philosophy and to review our record. With your help, I know we can improve our image, and the public&apos;s recognition of our industry&apos;s peculiar problems.

Jan 4, 1968

By Robert M. McGeorge, Edward S. Frohling

Most mining engineers and metallurgists who get out of school usually wind up working for a large or medium-sized company and are seldom heard of again. The enterprising few who decide to go into business for themselves soon discover that while they can adequately tackle the various technical problems involved in developing a new ore body, they know little about putting together a feasibility study-and even less about financing their project. If you are in that predicament, you&apos;ll probably tend to view the financing problem as insurmountable, especially when the economy is in a slump, capital is scarce or seemingly non-existent, the equity market is in the doldrums, labor and equipment costs keep going up relentlessly-and, to make things worse, you must operate within the competitive context created by large mining firms that seem to have in abundance all the capital and managerial expertise you feel you lack. If it&apos;s any consolation, many potentially successful properties, whether owned by big companies or small firms like yours, never reach the production stage either because of illogical expenditures made in the early phases of development or because of inefficient management. And inefficient management is a common plague in big and small companies

Jan 9, 1975

By Amos P. Brown

PYRITE, the bisulphide of iron, FeS2, is found more or less in all coal-beds: but, as a rule, in certain definite forms. More than any other impurity, it detracts from the commercial value of a coal-deposit, and yet its presence is so universal that it might almost be said that there is no coal entirely free from pyrite. My observation has been confined to the Pennsylvania bituminous and semi-bituminous coals, and to them, therefore, my remarks will be confined. Certain generalizations which I may make, however, will be found of universsl application. The lowest members of the coal-formation, No. XIII. of the Pennsylvania bituminous region, are nearly always pyritiferous, and in many cases highly so. In Cambria county, for instance, coalbed A, the Brookville, is locally known as the " Sulphur seam." The Lower Kittanning, in parts of Clearfield county, is so sulphury as to be almost unmarketable, though otherwise it is a strong locomohive coal. In Mercer county the Pardoe bed, so extensively mined there, carries great quantities of sulphur in the form of pyrite, though usually this can be separated in such a way as to detract little from the market-value of the coal. The other coal-beds of the Lower

Jan 1, 1888

Your outgoing President, following the worthy example of distinguished predecessors, submits a reckoning of his stewardship. He renders this fully realizing that without the hearty cooperation of Directors and Secretary, which he here recognizes most cordially, no President, who at best is but a passing force, can achieve markworthy results. The details as to your membership, finances, intellectual output, and,-other activities, have been submitted in the report of the Secretary.* It is enough to emphasize that during the year just expired, your organization has held two of its most successful meetings-one the largest in its history-has produced the largest number of papers, eliciting most interested discussions, has enjoyed its greatest income; and has received more than one thousand new members-passing the best previous record by more than one hundred, and exceeding the average increment of the, past five years by one third. It closes the year with 6528 members, the largest enrollment in its history. All of this might be true and yet the intellectual and social spirit, the loyalty of membership, the real life of the organization, might remain stagnant. As to these, it is for others than your speaker to testify. No comparison is feared.

Jan 3, 1918

By J. Mazia, H. Rosenthal

An investigation has been made of residual stress in the head and body of caliber 0.30 cartridge cases. The head was divided into four ring-lie sections which were cut off by a jeweler&apos;s saw. Spring-out was measured after a radial cut had relieved the circumferential bending moment. The residual stress corresponding to the observed spring-out was calculated by formulas in which the computed stress was a function of wall thickness. All rings sprang open, indicating compressive stress on the inner wall and tensile stress on the outer wall. The production stress-relief anneal of 475 F. for 45 min. reduced the stress to almost half. The priming and crimping operation, however, again raised the stress, especially in the flange section. The dect of stress-relief heat treatments on residual stresses in the body of caliber 0.30 cartridge cases was investigated by the split-ring method. Although this method did not reveal any large stresses in the body, the neck before mouth anneal was found to contain a computed stress of 30,000 psi. at the surface. This value was reduced to 15,000 psi. in 120, 30, and 15 min. at 400, 475, and 500 F., respectively.

Jan 1, 1945

By H. S. Chiang, S. S. Peng

INTRODUCTION Underground coal mining disturbs the original in-situ conditions which induces a series of strata activities and results in creating "mine pressures," the source of all ground control problems. Adoption of self advancing powered supports in modern longwall mining adds a new dimension to ground control problems and thus research. Roof stability, in general, refers to the integrity and stability of the immediate roof which is measured by the maximum exposed area and time duration without support. There are many factors that con- tribute to roof stability problems. In addition to mining height, rock property and stratum components and caving angle of the immediate roof, characteristics of joints and fissures and their degrees of development, faults and underground water, the operational techniques also play a very important role. This paper summarizes these operational techniques and methods of controlling stable and unstable roof. CLASSIFICATION OF THE IMMEDIATE ROOF There are many ways of classifying the roof (1). For practical purpose, the immediate roof in this paper is divided into three groups, i.e. unstable. medium stable and stable. Unstable Immediate Roof It has the following features (1) It consists of weak or soft carbonaceous shale, black shale, clay shale and well-jointed or fractures sandy shale

Jan 1, 1983

By David White

ATTENTION has been given to the sources and supply of the raw vegetal matter and. the conditions of its submission to the process of sedimentation. An original and most valuable review has been made of the more important or significant chemical compounds originally contained in the organic debris, and of the biochemical changes-undergone by the latter during deposition. Consideration also has been given to the factors controlling the selective biochemical decomposition, in whole or in part, of :this debris, and the deposition, as, sediments, of the undecomposed plant structures and compounds, together with more or less of the so-called "ulmic," or "humic," organic decomposition products in colloidal solution.1 BIOCHEMICAL CHANGES END IN PEAT FORMATION The biochemical process terminates in the peat stage of coal formation, and with the cessation of this process organic sedimentation is completed. All subsequent changes result from geological causes and conditions. The deposits are in the form of peats of different types, organic muds, oozes, etc. They are essentially uncompressed and are wholly unconsolidated, and their water content is great, amounting to over 85 per cent. near the surface of the deposit. Many of the chemical compounds remain as in the once living organisms; others are biochemically broken down and new ones formed.

Jan 2, 1925

Jan 1, 1947