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By Feilding C

Vitrinite of humic source (often designated as vitrinite A) is the maceral by which the rank of a coal ought to be determined. Therefore its recognition, and the precise identification of other vitrinites is essential. The majority of Australian petrologists are not differentiating between the vitrinite group macerals in maturation studies, the results of which have led to unexplained phenomena in coal characterisations and evaluation, such as 'reactive inertinites' and inaccurate predictions in petroleum source rock studies. The Callide coal has been chosen as a case study, with examples from other coals. The coal seams from the Callide Coal Measures show variation in the predominance of some macerals, indicating successions of environmental changes. The application of transmission electron microscopy (TEM) to the study of the Callide coal has enabled a better understanding of the nature and origin of some of the less understood macerals such as micrinite and vitrinite B. Two forms of vitrinite have been observed, each with a distinct reflectance range. The wood-sourced vitrinite A displays an average reflectance of 0.56 per cent, and a range of 05. - 0.7, implying a higher rank than the 0.49 per cent Ro total vitrinite reflectance recorded in previous publications. Vitrinite B is one of the most commonly-occurring macerals in the Callide coal. The lower-reflecting vitrinite B which forms bands, often several hundred microns in thickness, in TEM appears to be electron transparent lipid rich. Vitrinite B is interpreted to represent accumulations of leaves, and is believed to be a major source of hydrocarbons in Australian sedimentary basins. The Callide coal has entered the oil window, and oil has been generated from some exinite, cutinite, and resinite, as evident from the amber to light brown fluorescence of exinite and the presence of exsudatinite in cell cavities and cleats. However vitrinite B, the major potential source of oil, is seen under the microscope to be generating oil, thus placing this coal at the top of the oil window. Micrinite, the origin of which has been much debated, occurs as cell filling or infill of spaces between laminations in vitrinite B.

Jan 1, 1991

By Om P. Pande, Larry S. Diaz

Modern mineral processing plants could not operate efficiently, or even exist, without instruments which indicate, record, control, and in some cases anticipate the many changes that occur in a process. Even in plants which are operated manually, instruments are used to tell the operator when he should turn a valve or press a handswitch. Accordingly, all mineral processing plant engineering and construction projects must give careful consideration to this area of design activity.

Jan 1, 1978

By M J. Thomson, P T. Burgin

The economic growth of Hong Kong and adjacent territories in Southern China is, to a considerable extent, dependant on air transportation, but the present Kai Tak Airport is incapable of expansion to meet future needs. After years of study, agreement was reached to build a new airport on the island of Chek Lap Kok, some 34 km remote from Hong Kong, with an ultimate capacity of 87M passengers and 8.9 Ml of cargo per annum. Apart from the building of the airport and its associated infrastructure (including a new town), other similar massive construction works have been necessary in the form of land reclamation from the sea and existing outer lying islands. The construction of bridges, tunnels, railways and highways are also an integral part of the project. The paper provides a broad overview of the concepts of the scheme (called The Airport Core Programme) and highlights some of the major operations and equipment being used in the projects, whose cost at 1992 prices was reckoned to he Hong Kong (HR)$l63hn.

Jan 7, 1997

By B. Q. Li, S. P. Song

"This paper describes an on-going research on developing coupled boundary element and finite element algorithms for the solution of thermal and electrodynamic problems relating to materials processing. The coupled methods are uniquely suitable for field problems involving composite regions, in which detailed information on field distributions within one particular region is of more interest and yet the solution can be obtained only if the effects of other regions are all considered. Problems of this type include heat transfer in multiple regions and also magnetic induction involving an infinite boundary. The hybrid boundary and finite element formulation, algorithm development and the applications are discussed. Two examples are given to demonstrate the capability and accuracy of the coupled algorithm for heat transfer problems. Various treatments of corner discontinuity are discussed. It is found that the double flux treatment is an ideal choice amongst those tested as it is easy to implement and also gives the most accurate solution. 1. INTRODUCTIONElectrodynamic and transport problems occur frequently in materials processing systems. Accurate solution of these problems is of great importance not only for our fundamental understanding of physical principles governing these phenomena in the processing systems but also for optimization of the existing processes as well as development of new processes. For this purpose, many numerical algorithms have been developed. These computational schemes in general can be classified into three categories, that is, the finite element and finite difference schemes and the boundary element scheme. The former two are domain based numerical algorithms while the latter the boundary-based algorithm.The finite element method, which is based on the variational calculus, is a very useful and yet popular engineering numerical method for boundary value problems defined over irregular boundaries. The use of the method requires the discretization of the entire domain. It can be applied to solve both linear and nonlinear problems, but is particularly powerful for nonlinear problems that involve the field variables defined within the computational domain. On the other hand, the boundary element method, with its root in the Green's function method, is very efficient for linear boundary value problems or nonlinear problems that involve field variables only along the boundaries. The primary advantage of the boundary element method lies in the fact that only the boundaries of the computational domain need to be discretized, and hence the dimension of the problem is reduced by one, compared with the finite element method."

Jan 1, 1994

By Ken Musgrave

"A program is described that helps managers and supervisors control maintenance more effectively. Work- order generation, preventive maintenance, repair parts inventory, planning and scheduling, reporting, analyzing costs, printing purchase orders and other functions are covered. Flexibility often permits integration with other programs such as payroll, cost accounting and materials management.The Role of MaintenanceMaintenance provides a service to allow the rest of the operation to do its job effectively. Its success should not be measured by maintenance cost alone, but also by its effectiveness in reducing downtime and maximizing production. It can make sense to spend more maintenance dollars if this results in an even greater contribution from increased production.The Cost of MaintenanceIn mining companies, maintenance costs can be as much as half of operating costs. Maintenance has generally not been given the management attention that an expenditure of this magnitude deserves."

Jan 1, 1986

By John B. Dilwoth

This paper treats primarily of the valuation of developed coal properties by the method of capitalizing their estimated average future earnings. However, reference is also made to valuations of undeveloped coal lands and to various methods of appraisal other than by future earnings. Fundamental Valuation Principles Before discussing in detail coal property valuations, a few statements bearing on the general subject will be made to present certain of the writer's views on the question as a whole. 1. A certain property at a given time has but one true value. This is not universally admitted. The appraiser rather frequently finds that a coal owner has in mind three valuations for his holdings; one, the figure at which he feels they should be appraised for taxation purposes; another, the much higher one that should be used if a loan is to be negotiated on the property; and a third, intermediate between the other two, the price for which he would be willing to dispose of his holdings were they for sale. The last is usually nearest to the true value, and because this is so the statement is generally accepted that the fair value of such a property is the price arrived at by negotiation between a willing seller and a willing buyer who are otherwise disinterested. 2. Notwithstanding the foregoing, it is only very generally and approximately true that the proper measure of the value of a given developed' coal acreage is the unit or per-acre price for which one or more bodies of similar coal in the same district have been sold recently. To give a few reasons why such a measure of value can not be strictly applied, it may be noted: a. That sales are often forced by circumstances at times when the coal business is depressed and buyers can be found only for properties that are offered at figures far below their true value. b. That conversely, during periods of unusual prosperity, abnormally high prices are paid. Such conditions obtained several years ago when coal brokers, with very profitable contracts but no sure source of supply, were bidding against inexperienced or shortsighted operators for proper-

Jan 1, 1928

The specification for tender nominated the requirements for ore hoisting and servicing; this showed that one common duty winder could be selected. Foliowing the design of the shaft layout, the merits of fixed or rope guides were compared and the latter selected.The specification called for the supply and installation of the complete hoisting system. Construction of the winder tower and shaft bottom steel work had to proceed while mine development was in progress using the sinking winder and headframe. Guide ropes, winder ropes, and the sky shaft were installed in the shortest possible time, and as the shaft was not equipped with ladder-ways, a second means of access had to be provided.Very few problems were encountered witll the commissioning of the winder, and in the first 2 years of operation the only significant modification was to the circuitry associated witll the moving access platforms.Hoist rope tension checking and adjustment are simple, and non-destructive testing has shown no deterioration of these ropes. The operation of the balance ropes has been very satisfactory but cleaning presented problems in the early stages. Guide ropes have been trouble free and require minimum attention.Normal wear on the PVC rope groove inserts on the winder drum has been negligible.Since the commissioning on fully automatic ·control, the winder has operated with very few, minor delays.

Jan 1, 1969

By T. T. Read

Personnel work is a term recently introduced to cover the great variety of activities in industrial work that deal with the human factor. Much attention has been focusscd upon individual phases of personnel work, such as accident prevention, sanitation, "welfare" work, reducing labor turnover, and so on. In most cases these activities have been carried on as though they were distinct and separate fields; as a matter of fact, they are only different phases of the single problem of human engineering, and each has important and fundamental relations with the others. Thus, for example, high labor turnover is one of the most important causes of a high accident rate, and unsatisfactory housing conditions are an important cause of labor turnover. In the early stages of the study of these problems, it was necessary to take them up separately; the time has now arrived at which it is desirable to consider them as a whole in order to bring them into the right relation to each other. When thus considered as phases of an interrelated whole, they may be grouped as personnel work. A discussion of the importance of personnel work as a means of increasing dividends in industry may be objected to by some as a too materialistic way of looking upon work that is humanitarian. Nothing could be more mistaken than such an opinion. Humanitarianism, per se, has no place in industry, and nothing is gained and much is lost in pretending that it has. The only reason why a corporation engages in business is to make profits, and any activity of the corporation that does not tend either directly or indirectly toward that end is poor business. It is equally poor business to overlook any activities that do tend indirectly to the making of profits. On this basis, personnel work can be justified as a corporate activity; there is no justification whatever for abstract *humanitarianism from the business standpoint. One characteristic of the American workman is a general high level of intelligence, and it is an insult to intelligence to ask a man to believe that anything so impersonal as a corporation is really desirous of benefiting

Jan 1, 1918

By Frank P. Traczyk

INTRODUCTION The process of solid-liquid separation can be an important decision in plant design. It is very important that one must consider not only the most effective means of solids-liquid separation, but also to consider the effects on upstream and downstream processes. A solid-liquid separation is done either to remove the solids £ran the liquids as in copper concentrates or rave a liquid from the solids as in uranium operations. In either case, washing can be an important consideration to clean the solids or recover the liquids. This section will deal with solid- liquid separation other than thermal, sedimntation processes, or hydro cyclones. The three major areas discussed are pressure filters, vacuum filters, and centrifuges that are most cannon in the minerals industry. PRESSURE FILTERS Pressure filters are one common type of solid-liquid dewatering devices. There are my different types of pressure filters that are both continuous and batch operations. They are characterized by using an external pressure to push or force the slurry through porous media to force the liquids out of the solids. Whereas vacuum filters are limited to one amsphere or bar working pressure, some types of pressure filters operate as high as 16 bars pressure. Pressure filters are also effective for hot slurries where a high boiling point can be a problem or precipitation occurs under vacuum. The types of pressure filters most common in the mineral processing industry include plate and frame and recessed plate filters. Some of the new technologies including automatic pres- sure filters and belt presses are also discussed. Plate Frame Filters Plate and frame filters are one of the oldest and most effective means of both dewatering solids and clarifying liquids. Plate and frame filters consist of a skeleton that is used to hang or support alternate plates and frames that are pressed together to form chambers. The filter plates consist of a drainage grid that is covered by sane type of filter media through which a liquid is

Jan 1, 1986

By B. F. Tillson

ALTHOUGH most accidents occur through the A carelessness or misfortune of the workmen; that is no reason why we should not take all physical precautions practicable. The best way to approach the problem of mine safety is to acquire a personal feeling of responsibility for the accident and then plan how it might have been prevented had we known that it was to occur. A statistical analysis of the physical conditions contributory to accidents will give an indication of some of the methods or mechanisms that should be revised or safeguarded. The handling of rock or ore is a common source of minor injuries. Freedom from accident when mucking largely depends on the skill and care of the workman; this also is true, to a certain degree, to loading cars from chutes, but much can be done in the layout of chutes and their equipment to provide equal safety with less skill. Permanent stagings, or rigid units that may be easily assembled, should be provided so that the men handling the chute boards or gates and barring the jammed chunks will have a convenient safe footing for their operations. A stance to the side of the chute mouth is to one in front, because a man will not be liable to be struck by flying lumps or his bar, should it he caught in the mass, yet in many mines the workmen face the chute when loading a car. Fig. 1 shows the operation of a plank chute having special latches which support the chute boards in such manner that they may be conveniently dropped into place to stop the flow of ore.

Jan 1, 1926

By F. Keith Jacobson

To be involved in the construction of a deep dredged caisson for a major bridge pier is one of the most rewarding and professionally challenging experiences one can have in the bridge construction business. That experience was doubled in the construction of the two deep dredged caissons for the Highway 82 Bridge over the Mississippi River near Greenville, Mississippi. The challenges and the construction risks associated with constructing these two dredged caisson pier foundations highlight the construction engineering innovation associated with major bridge pier construction. The 1,378-foot Main Span of the Highway 82 Bridge makes it the longest cable stayed bridge span over the inland rivers of the United States. The main piers for this bridge are supported on two dredged caissons measuring 80-feet by 122-feet in plan, founding 200-feet and 170-feet below the river surface. The challenges of constructing these caisson structures, sinking them through 70-feet of water to the river bottom and then excavating and further sinking them to the founding grade without exceeding the design tolerances, were enormous. The construction engineering opportunities for innovation included major breakwater structures to create a friendly environment in 11 fUsec currents, the first time use of Articulated Concrete Mattresses for river bottom scour control, unique air dome design to maximize the buoyancy of the caisson structure while floating, a caisson guide system to assure positive control and positioning of the caisson during the initial sinking phases. and a comprehensive sinking plan to assure maximum control and minimum risk. Many of the innovative solutions to the construction challenges on this bridge will be incorporated into future caisson construction projects on the lower Mississippi River.

May 11, 2007

By A. D. Garman

This paper presents one of a series of digests of foreign mining legislation and court decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the laws of Nicaragua has been prepared from the best available information in Washington , but is released subject to correction and amplification , if necessary, by the proper American diplomatic and consular officers to whom it is being referred through the courtesy of the Department of State .

Jul 1, 1930

By D. A. Phillips

A procedure for designing an optimum pit to yield maximum profit is described. The volume in which a possible pit is considered is divided into discrete blocks, each of which is assigned an economic value equivalent to its worth as a block of mineable material. The profitability of a pit can then be generated by summing the blocks within the pit. The optimizing procedure starts at the surface level and proceeds downwards level by level, to obtain the optimum pit at each level. The method makes use of the fact that an optimum pit at a particular level must be completely contained in any optimum pit at a lower level. Procedures for generating block costs, and pits with various slope angles under the restriction of complete block removal are considered briefly. The main description is of the theory of the method and the computer program based on this. The method is applicable to any type of mineral deposit, the only requirement being that the orebody should be represented accurately by a block model.

Jan 1, 2014

By B. D. Thomas

When the origin and early plans, of Battelle Memorial Institute were described in this journal in October 1929 by R. W. Gillett the first director, the doors of the laboratory had just been opened and the hope of the founder that the institution serve the world by research for industry still existed only as an ideal in the minds of the thirty or so employees who then constituted the staff. Since that time the country has experienced troublous times. A devastating depression plunged the entire world into an unprecedented period of financial and industrial inactivity; and the slow recovery of the late thirties was soon to be overtaken and overwhelmed in the violence of war. Through this time of stress Battelle has continued to grow. The staff has increased to almost 600; buildings and equipment have been added, until now it stands in a place of pre-eminence in the metallurgical and engineering world.

Jan 1, 1944

By Somasundaran P., M. Vasudevan, Z. Dai, D. R. Nagaraj, T. Bhambani, P. Patra

Historically, efficient beneficiation of ultramafic ores has been challenging, partly due to a lack of clear scientific understanding of the effects of Mg silicates, particularly fibrous serpentines, on selective Ni recovery. Recent research at Columbia-Cytec as a part of a Vale JDP project has led to new insights into the mechanistic aspects of the adverse effects of Mg silicates. Our research has provided strong evidence to support the hypothesis that the adverse effects of Mg silicates are mediated through their large influence on pulp rheological properties, far more than any other pathway. The severity of the effect of Mg silicates is predominantly dependent on the aspect ratios of Mg silicates. For example, the pulp viscosity increases dramatically with increase in the fibrous nature of the gangue mineral leading to poor Ni separation. Various ways by which the suspension rheology affects flotation sub-processes, with implications for remedy are discussed. The insights and results have served to develop (or construct) a phenomenological model to adequately explain all of the ore flotation data, particularly the Mg silicate transport to the froth phase and the concentrate.

Jan 1, 2011

By E. Berl

THIS may be a most unnecessary paper-from what does crude oil come and how was it formed? Many people, inside and outside of the petroleum industry, believe that we have actually enough oil, and that we can easily produce very important products from this extremely valuable raw material. The writer believes, however, that the answer to this question concerning the parent material and the formation of oil is of broader interest, because it may be that from the answer to these problems it would be possible to get answers to other important indus-trial questions. Therefore, a study in this line seems to be justified, and the writer will submit some of the results which he has collected during more than ten years with many very capable collaborators, to whom his thanks may be expressed on this occasion.

Jan 1, 1938

By C. B. Dudley

IN the spring of 1877, the Pennsylvania Railroad Company became so dissatisfied with the average life and wear of the steel rails it was then able to procure, that it determined to make an investigation into the chemical composition and physical properties of steel rails, with a view, first, to answering the question why one steel rail has to be removed from the track after, perhaps, eight months' service, while another lasts ten years ; and, secondly, if this investigation succeeded in throwing light on this important subject, to use this information in securing better rails in the future. The results

Jan 1, 1879

By Charles B. Dudley

In the spring of 1877, the Pennsylvania Railroad Company became so dissatisfied with the average life and wear of the steel rails it was then able to procure, that it determined to make an invest,igation into the chemical composition and physical properties of steel rails, with a view, first, to answering the question why one steel rail has to be removed from the track after, perhaps, eight months' service, while another lasts ten years; and, secondly, if this investigation succeeded in throwing light on this important subject, to use this information in securing better rails in the future. The results

Jan 1, 1879

By V. N. Kolesnikov

The gold-silver deposits of the northern Primorye region are located in the eastern part of the East Sikhote-Alin volcanic belt, where the belt overlaps the Kema island-arc terrain of the Aptian-Albian age. There have been four deposits and numerous mineralization points found in the NE-trending Kema metallogenic belt that is about 1000 km long and 100 km wide. The known mineralization is of epithermal type, controlled by faults, and concentrated in quartz, quartz-fluorite-adularia, and, less commonly, sulfide-quartz vein systems hosted by the Upper Cretaceous-Lower Tertiary volcanic rocks. The vein systems extend for hundreds meters along strike, varying from tens centimeters to 50-60 meters in width. They are surrounded by wide zones of low-temperature hydrothermal alteration containing some gold-silver mineralization for which the commercial value was not studied during the early exploration. The ore bodies contain from 1 to 50-80 ppm of Au and from 1 to 1000 ppm of Ag. Gold is native, associated with quartz, and represented by particles from tens of microns to 1 mm in size. Silver occurs in native form as a constituent of argentite, pyrargyrite, stephanite, and other sulfosalts. The test work carried out for three vein systems 20 years ago showed that gold might be easily and almost completely recovered from the ore by cyanide treatment. The paper describes the geology and mineralogy of the deposits, Salut and Primorskoye, that are the most studied properties of the Kema belt. It also presents the data available on disseminated gold-silver mineralization in stockworks, altered explosive breccias, and wide zones of low-temperature hydrothermal alteration. This mineralization should be explored for possible exploitation as large open-pit, heap-leach deposits.

Jan 1, 1998

By Jie Ma, Shun-Li Zhao, Jian Zhao, Jie-Yu Zhang

"Microstructural morphology evolution of Ni-45wt.%Mo droplets during rapid solidification process was investigated using an advanced modified 3D cellular automaton-finite element(CAFE) model by CALCOSOFT software. The model was modified by User-defined functions (UDFs) and validated with experimental solidification microstructural morphology of Ni-45wt.%Mo droplets available in the literature. Then, the influences of convection heat transfer coefficient, superheat of the alloy droplets and droplets size were investigated during the rapid solidification process. The predictions show that microstructural morphology is obviously sensitive to convection heat transfer coefficient and droplet size. With the decrease of convection heat transfer coefficient, the grain density decreases. In addition, the decrease of the droplet size could obtain refined microstructure. However, decrease the superheat ofNi-45wt.%Mo droplets has little effect on microstructural morphology.IntroductionFor several decades, much attention has been paid to undercooled alloy droplets of rapid solidification process for which can obtain refined microstructure, decreased microsegregation and extended solubility of alloying elements [1-3]. Extensive prior work shows that solidification of droplets plays an essential role in advanced material properties [ 4]. Consequently, it is very important to investigate the microstructural morphology evolution, especially for dendrite growth during non-equilibrium solidification process, for dendrite growth reflected the kinetics of the crystal growth process."

Jan 1, 2013