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T. W. ROBINSON, Pueblo, Colo.: Mr. Potter's review is a striking testimony to the important part played by science in this branch of practice. But, the question arises, In which department has science effected most ? The available raw material, the size of furnaces, the general design and equipment of the plant, and the daily management, are particulars, each of which contributes to the general result, while the effect of each merges into that of the others. The following notes concerning the operations of the furnace-plant of the Colorado Fuel and Iron Company (formerly the Colorado Coal and Iron Company), at Pueblo, may throw some light upon the question of their relative importance. This company operates three stacks, and when the plant first came under my observation, about nine months ago, the furnaces were constructed, equipped,and run as stated below: Raw Materials.—The main sources of ore-supply were, as they still are, the Orient and Calumet mines of the company. The Brecce and Morning Glory ores, mentioned below, were formerly brought from Leadville, but are practically now no longer used. The Orient ore is a porous brown hematite, easily reducible in the furnace. The Calumet is a magnetite, very refractory in character, requiring preliminary roasting. Both are fairly uniform in composition. The Breece and Morning Glory are red hematites, resembling in appearance the soft ores of the Vermilion range, Lake Superior. The coke here used is made of coal from the company's mines in southern Colorado, and is distinct from that produced by the company in the western part of the State. The structure is similar to that of Alabama coke. The limestone employed is a calcite. The analyses are given in Table I. I would note, parenthetically, that I know of no section of the country presenting harder conditions for furnace-practice than these materials impose. Results cannot be measured by the more

Jan 1, 1894

By T. M. Geffen, H. N. Hall

One-third to one-half of the original oil is left in most reservoirs even after thorough gas driving or waterflooding. In contrast, essentially all of the oil contacted con be recovered by flooding with a solvent (a fluid miscible with the reservoir oil). It is not economical to fill a reservoir with solvent since the value of the solvent would very likely exceed that of the oil. A practical method would be to inject a small bank of solvent to displace the oil. This solvent bank in turn could be driven through the rock by a less valuable scavenging fluid, such as natural gas which is also miscible with the solvent. Such a method of oil recovery was studied in the laboratory using long (up to 95 ft) core systems. It was found that, as the solvent moves through the reservoir, the front end of the solvent bank becomes mixed with the oil and forms a relatively short mixing zone between undiluted crude oil and pure solvent. An engineering correlation was obtained which can be used to predict the length of this zone. Displacement of the solvent by natural gas can be achieved with complete miscibility (above the critical pressure of the gas-solvent system at reservoir temperature) or with partial miscibility at lower pressures. Under conditions of complete miscibility, it was found that the length of the gas-solvent mixing zone could be predicted from the correlation developed for the solvent-oil mixing zone. With partial miscibility, two phases exist and the solvent is displaced by a modified gas drive in which vaporization and condensation occur. Equations are developed to predict the performance of this type of displacement. Two plans are suggested for application of miscible fluid displacement. one for miscible displacement of the solvent and the other applying to lower pressures where partial miscibility occurs during solvent displacement. Calculations based on the laboratory tests indicated that a bank of solvent with a volume of less than 10 per cent of the hydrocarbon volume under consideration will generally be adequate to obtain high oil recovery from the portion of the reservoir contacted in miscible fluid displacement. INTRODUCTION The conventional methods by which oil is displaced from reservoir rock—solution gas drive, conventional gas drive, and waterflooding—are all processes in which the oil is expelled from the rock by direct displacement with a fluid immiscible with the oil. Because of the immiscible type displacement, complete recovery of the reservoir oil is not achieved. In economically successful flooding operations, as much as 50 per cent of the original oil may be abandoned in the reservoir as unrecoverable. The use of a solvent (miscible with oil, such as LPG) as an injection fluid does not have the undesirable displacement features common to the use of gas or water (immiscible with oil). It can be readily appreciated, however, that it would not be economically feasible to displace the oil and entirely replace it with a solvent. A process was therefore devised for use in field operations in which only a small volume of solvent would be required to obtain essentially complete oil recovery in the portion of the reservoir contacted. In this process, the solvent acts as a buffer between the reservoir oil and injected gas, allowing the natural gas to displace indirectly the oil with much greater efficiency than if the gas displaced the oil directly. DESCRIPTION OF OIL RECOVERY PROCESS The solvent oil recovery process will be described in

Jan 1, 1958

By Wilbur H. Grant

THE property of the United Comstock Mines Co. lies in the eastern foot-hills of the Sierra Nevada Mountains, in the Washoe mining district of Storey County, Nev. Commencing at the boundary line between Virginia City and Gold Hill, covering all the town of Gold Hill, it extends south to American Flat; the main camp, or the new town of Comstock, the mills, shops, residences of employees, and the main haulage-tunnel portal are located on American Flat. The property extends for about 10,300 ft. along the lode; this covers the southern end of the main Comstock lode, the Knickerbocker branch, and the junction of the Silver City branch with the Comstock lode. Within the property, 5000 ft. of the main Comstock lode is known to have been productive, 1000 ft. of the lode at the northern end of the property is thoroughly developed, and 1000 ft. south of this is partly developed; this leaves about 3000 ft. of the known productive portion that has not been opened up by this company. The northern end of the property, or the Imperial mine, has been intricately developed by five main levels and numerous sublevels. The Yellow Jacket ground to the south has been partly developed by the reopening of three old levels. In addition, the main haulage level is driven from the portal at Comstock for 9250 ft., to the north end of the property; about 5500 ft. of this `is in the foot wall of the lode and parallel to it.

Jan 11, 1922

By A Scott

Long before a modern mine commences operations it has already become a wealth of information. After start up, it can generate enormous quantities of data û especially with semi-automated data acquisition by instrumented mine equipment. However, much of this data is of limited use for evaluation of (potential) performance unless it links in some way to the site business model. An underlying reason for this waste of data is that the different cultures, financial, technical, community, environmental, etc not only have many areas of interest but also have very different conceptual models by which they evaluate performance. It is too ambitious to attempt to bring all of these cultures together û in a single step. However, the success of the Mine to MillTM project has demonstrated that substantial operational value can be added by using a more integrated approach to comminution. The next logical step is to integrate measurement and then to track performance from orebody model to saleable product and waste disposal. From resource to product also represents a path from very sparse, highly variable data to much more detailed measurement and more representative sampling. However, in both cases the data collected is strongly focused on the technical requirements û not on the business model. This paper considers how to define at least some of the key decision points in terms of some case studies. Performance data from many areas might be used to derive simple models which can then be used for forecasting and optimisation of planning.

Jan 1, 2002

By Charles A. Kliche

INTRODUCTION The Northern Great Plains Coal Province which occupies approximately 36.6 ha contains about one-half of the nation's total coal resources. About one million ha are underlain by coal that is considered to be mineable from the surface. The topography of the province is predominately plains, rolling hills, and some badland areas characterized by breaks or sharply eroded hills. Elevations range from about 1500 m above sea level on the west to about 600 m above sea level on the eastern boundary. The average slope of the ground is approximately 2 m per km. Streams in the province drain generally easterly and southeasterly (1). In the United States, the Northern Great Plains Province lies within the states of North Dakota, South Dakota, Montana, Wyoming, Nebraska, and Colorado. The coal within the province is located almost entirely in the states of North Dakota, Montana, and Wyoming. Although it is relatively low rank, the coal within the province encompasses a large portion of the total remaining U. S. reserves. The U. S. Geological Survey estimates the total remaining coal resources of the United States to be 2.6 trillion mt within 1000 m of the surface, and 2.9 trillion tons within 1830 m of the surface. Of this total, only about 177 billion mt are classified as reserves meaning that they are (1) known in location, quantity and quality from geologic evidence supported by engineering measurements, and (2) economically recoverable based on currently available technologies and current market value (2).

Jan 1, 1983

By Don Blackmar

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

Jan 1, 1928

By Don Blackmar

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

Jan 1, 1928

By George B. Pryde

Dear Sir: Yours of July 23rd, relative to my appointment on the Safety Committee in connection with the Rocky Mountain Coal Mining Institute. As you say in your letter, "The duty of this committee is to draft suggestions as to safer mining practices with the idea of preventing disasters in coal mines." Much has been written and many suggestions made on this same subject, and it is very hard to put up further recommendations than have already been made. The disasters you mention in your letter unquestionably have direct reference to coal mine explosions, which from time to time still occur in this and other countries. As far as our Western mines are concerned, you know that sprinkling and shot firing by electricity have been very extensively carried out. Notwithstanding these precautions; we have had a few rather serious disasters in the past in these mines. I do not care to place any blame or responsibility on the companies having these disasters, but it is a fact that in each and all of them, after careful investigation has been made, that the human element has had more or less bearing on the accidents happening. From most reports that we gain, either directly or indirectly, it is very evident that investigation shows after an explosion that the rules governing one or both of the above safety measures have been somewhat carelessly or negligently carried out. Much has been written and read about rock dust sprinkling, but it is questionable if this method is doing a great deal toward the eliminating of disasters. While it is true it may have the effect of preventing propagation, still I do not believe anyone claims for it a sure preventative against initial explosions. I had occasion not long ago to visit a mine, after an explosion, in which dust barriers were supposed to be hung, and from indications it was quite evident that the dust barriers had been in operation, but they did not prevent the explosion from reaching all open parts of the mine. It is also true that profuse scattering of rock dust throughout a mine would have a beneficial effect, but there is a question arises here as to whether the sprinkling by rock dust or the spraying by water, if available, is the most effective. I am satisfied that if all coal mines are kept well sprinkled and all open workings maintained in a thorough moist condition, that the biggest factor in a coal mine explosion is in this way eliminated. There is no doubt but what the use of permissible powder, particularly if shot by electricity, has had a very marked effect on the number of disasters in mines, and if this method of shooting was energetically carried out there would be a difference in the number of explosions, both minor and Major, all over the country. Some of the recent explosions have taken place where no shooting was being done, but there is no denying the fact that the other ingredient, namely, coal dust, entered in the elements very extensively. We have read and heard of hydraulic cartridges and other patents (substitutes for powder) that were being worked out for the purpose of

Jan 1, 1923

By V. D. Perry

AS the traveler approaches Chuquicamata from the seaport of Antofagasta, crossing in a northeasterly direction the 150 miles of coast range and completely barren pampa with its low, rolling hills and broad depressions, the gradual rise to an elevation of 9000 ft is imperceptible, and it is hard to realize that the smoothly contoured hills east and west of the mine are from 10,000 to 11,000 ft above the level of the sea. The deceptive monotony of the scene is relieved only by the background of an unbroken line of lofty volcanic peaks, part of the Andean Cordillera, which rise, snow covered, against the eastern skyline. The drab geographical foreground is matched by the geological monotony of unaltered, gray rock

Jan 1, 1952

By Dr. T. L. F. Muller

INTRODUCTION During the past decade a wealth of knowledge has been acquired about the mechanisms and reactions responsible for the physical properties of metals. In the field of steels, in particular, research of a fundamental nature has enabled us to interpret mechanical properties such as hardness, brittleness, creep strength, etc., in terms of atomic interactions. So rapid has been the development of physical metallurgy in some fields that publications are often outdated by the time they appear in print. The development of new steel products has been rather empirical by nature in the past and only during the past few years have new products been "designed" in terms of known physico-metallurgical phenomena. However, although this is a great stride forward it should be added that the development of a commercially successful product is a far more complicated process. In addition to the physico-metallurgical background this requires consideration of factors such as low production cost, market research and probably most valuable of all, an interested end user to co-operate in the development. This paper deals rather briefly with three of the most recent developments in steels in Britain with which the author has had some association. The main purpose of this is to demonstrate how the improved properties of the new product are based upon established physico-metallurgical phenomena. Generally speaking a commercially successful product of the type described here offers similar properties to that of an existing product at lower cost or has improved properties or features such as greater ease of cold forming, at similar cost. ULTRA-FINE GRAIN STRUCTURAL STEELS The development of higher yield strength structural steels dates back over a considerable number of years and has led to a variety of types. The one described below contains niobium as a grain refiner in an otherwise conventional mild steel matrix. By controlled rolling in a strip mill considerably increased yield strengths are obtained. In Fig. 1 are shown somewhat diagrammatically the relative hardening effects of carbon and manganese on ferrite. It will be seen that strength is enhanced by the solid solution hardening effect of manganese and the pearlite content. An obvious limitation of high pearlite content is a lack of cold workability and weldability. Manganese has to be restricted to low levels for the same reasons. The two other mechanisms which are known to impart higher strength are precipitation hardening and grain refinement. Precipitation hardening is impractical in most cases for structural steels and it is therefore clear that only grain refinement remains as a potentially useful strengthening mechanism.

By B. F. Fackenthall

The Durham Iron Works of Messrs. Cooper & Hewitt, near Riegelsville, Pa., occupy a site which has been almost continuously the scene of iron-manufacturing industry since 1727. Doubtless if Anthony Morris and his thirteen associates, who in that year erected a blast-furnace on the Durham Creek, a short distance above where the Durham Iron Works now stands, could have had a vision of the improved and enlarged apparatus of their successors, they would have been not less astonished by the huge stack, the hot-blast ovens, and the blowing-engines of the modern blast-furnace, than by the railroad which now follows the bank of the river on which their clumsy " Durham boats " once floated pig-iron to Philadelphia. In one particular, posterity must confess their snperiority. We are told that in November, 1728, they shipped three tons of Durham iron to England. The proprietors of the Durham Iron Works are not now shipping iron to England. The present Durham furnace was built (in place of two smaller ones) in 1874 and 1875, and made its first blast in 1876. A description of it, with other works of the same proprietors, at Trenton, N. J., by A. L. Holley and Lenox Smith, was published in London Engineering for January 31st, and February 21st, 1879. Since that time, a number of improvements, dictated by experience, have been made in the details of the furnace and fittings; and the recent roilclusion of a long and successful blast presents a convenient opportunity for a description of the works and a statement of the results of practice. The accompanying drawings will show the general arrangement of the works. The furnace, Plate I., Figs. 1 and 2, is 75 feet high by 19 feet bosh. The hearth is 11 feet 4 inches in diameter, with seven tuyeres 5 feet 6 inches above hearth-line. The tuyeres project 9 inches into the furnace, making the interior tuyere-circle 9 feet 10 inches in diameter. The front is a modification of Luermaun's

Jan 1, 1886

By Kaye P. Strong, Desmond M. Levins, Anthony G. Fane

1. INTRODUCTION The safe disposal of tailings is the most important environmental question facing the uranium mining industry today. This is because tailings present a major long term radiological hazard as they contain about 71% of the radioactivity originally in the ore. The magnitude of the problem can be appreciated by considering the quantity of tailings involved. For example, projections of milling programs in Australia indicate that there will be 100 million tonnes of tailings produced by the year 2000 (Levins 1980). The United States currently has in excess of 100 million tonnes and by the year 2000 will have between 900 and 1700 million tonnes (Landa 1980). Present options for tailings rehabilitation include leaving them above ground, returning them to the mine or placing them in specially excavated pits. In any event, the tailings will be covered with earth and revegetation attempted. This will remove the problems of airborne radioactive dust and water erosion of the tailings, at least in the short term, but diffusion of radon-222* from the tailings may still occur. The Atomic Energy Control Board of Canada (1981) has proposed a maximum allowable radon flux from rehabilitated tailings of 0.074-0.37 Bq m -2s-1(2-10 pCi M-2 s-1); the exact level is to be determined "after discussion with other regulatory agencies and the industry". The United States Nuclear Regulatory Commission (USNRC 1980) has been more restrictive in recommending a maximum flux of 0.074 Bq m -2s-1 (2 pCi m-2s-1). As a guideline they also suggested a minimum depth of covering material of 3 m to achieve this surface flux for tailings typically found in the western milling regions of the United States. The design of rehabilitation schemes is aided by a knowledge of radon transport through tailings piles. In this paper we present the results of a theoretical analysis and experimental study of radon diffusion through selected Australian tailings and cover material. The minimum cover criteria of 3 m is reexamined in the light of these findings. [ ]

Jan 1, 1981

By John Furness Park

The mining district is located in the northeasterly part of Nevada, between the Jarbidge River on the west and the East Fork of the Jarbidge on the east. The northern boundary of the district is but a few miles south of the Idaho state line—the gold-bearing area extending from this point south, for 5 or 6 miles. • The Jarbidge Mountains, in which the ore deposits occur, range from 5000 to 11,000 ft. in elevation, the most important mines being situated about 7000 ft. or higher. The town of Jarbidge lies along the Jarbidge River and is reached by stage from Rogerson, Ida., the nearest railroad point. During the summer months, the camp may be entered from the south by way of Deeth, Nev., but no regular transportation facilities are available over this route. History The mineral deposits were not discovered until 1909, when D. A. Bourne, panning along the river bank, found gold in. the gravel at the mouth of a small stream flowing into the Jarbidge. He prospected in the vicinity of this stream, later known as Bourne Gulch, and shortly after located the North Star claims. During the following spring and summer (1910), the camp of Jarbidge grew from nothing to a town of 2000 people and the hills surrounding it were practically all taken up by mining claims. Most of the work done during the first year or two consisted of trenching and open-cut prospecting. Tunneling was started on a number of claims and many veins were uncovered. Mills were built and operated on a few properties, notably the Pavlak and the North Star. These ran only a few months, however, when they were closed down because of extraction and financial difficulties. A period of development followed in which the majority of the present producing mines were opened. The Elkoro Mines Co. acquired a number of claims in 1915 and started work on the present mill in 1917. Since that time other properties have been taken over until this company is by far the largest operator in the district. Only one other company is now actively engaged in mining, the Bluster Mining & Milling Co., which has

Jan 1, 1925

By T. Ward, K. Shah, K. Murray

The mining industry is processing deposits with ever decreasing grade at ever increasing operating costs while margins are under constant pressure by material substitution and recycling. We are reaching the point where building it bigger just isn’t good enough as social and environmental constraints become more intense. In response to the growing demands on our industry, Goldcorp has embarked on a journey to increase resources by converting Waste to Ore. Gravity pre-concentration and sensor sorting testwork has been completed on samples from our Canadian operations in order to determine the amenability of our mineralized waste to sorting and upgrading. As expected some material was amenable to sorting and a review of the economics supported demonstration plant testing. The ability to economically sort mineralized waste into ore and barren rock is being demonstrated by Goldcorp. It has been made possible by leveraging the experience mineral sizer manufacturers have gained in the oil sands and hard rock applications, seeking more energy efficient screening machines and embracing the advancements that ore and recycling sorter suppliers have achieved. The paper will discuss the testwork and results achieved to date from both the lab and demonstration plant.

Jan 1, 2018

Gunpowder Copper Limited processes 1,000 tonne/day of Mammoth ore in a conventional flot- ation concentrator. Run of mine ore is prepared for flotation by three stages of crushing and two stages of ball milling. The concentrate, in which the primary copper mineral is chalcocite, is solar dried and exported to Japan. The history of operation is summarised, and plant practice and metallurgical problems are discussed.

Jan 1, 1974

C. W. GOODALE, * Butte, Mont.-In regard to the employment manager, the North Butte Mining Co. has undertaken that line of work and the rest of the companies are watching the experiment. If it is proved to be the proper thing, the system will be introduced into other mines. We have to combat the opposition to the use of the "rustling card. It is nothing more nor less than asking the nationality, where the plan formerly worked, and whether he is married or single. ROBERT RHEA GOODRICH, Anaconda, Mont. (written discussion?).¬Since the efficiency of the different phases of personnel work employed by industrial concerns, which are bringing about greater efficiency and lessening the labor turnover, the latter being intimately connected with "contentment of mind," depends on the individual workman, it is highly desirable, as far as industry is concerned, to keep the workman's mind and body in trim in order to lessen accidents and produce a higher grade of work. Prevention being better than cure, health supervision of the workmen during employment should be maintained by the employers in order that mental alertness and physical well-being may be obtained. I have long believed, from observation in many plants, that when any problem is dependent on the individual workman, what he believes and what he does is vitally dependent on his health. I will follow with much interest what is to be clone in the future in relation to the subject of health supervision during employment (as well as medical examinations at the time of employment), and I hope this idea will be generally instituted in personnel work. A workman with good health and a contented mind should be an ideal component of a progressive industrial concern. The contentment of the workman is fostered by a number of admirable phases of welfare work which are being still further developed. The mental and physical well-being of labor should be the issue in Labor vs. Capital in the new period of the industrial promotion of the United States into which we are now entering.

Jan 4, 1919

By Charles Dorrance

Culm is a general term used in the anthracite regions for many years to denote a mixture of coal, bony coal and impurities which is sent to the refuse-banks. Thus, 35 years ago culm contained the pea and buckwheat sizes of anthracite; but to-day, and as mentioned in this paper, culm is used specifically to denote the material which passes through the smallest screen in the anthracite-breaker. The smallest size of commercial anthracite is known as No. 3 buckwheat, barley, or bird's-eye coal, and is ordinarily made through a round-punched plate having openings & in. in diameter, and over a round-punched plate with openings 3/32 in. or 1/16 in. in diameter. Thus culm will consist of coal, bony coal, slate, gravel, iron pyrite, etc., ranging in size from 3/32 in. down to dust. Other local terms for culm are " slush," " silt," and " dirt." The first experiments towards the utilization of anthracite culm by briquetting, and the first briquetting-work done in this country, were in 1872 at Port Richmond Piers, Philadelphia, Pa., by E. F. Loiseau.1 Clay was used as a binder and the finished briquette was water-proofed with shellac, etc. Excessive cost was given as the reason for discontinuing work at this plant.

Jan 1, 1912

By Warren E. Wilson

PRESENT-DAY design of launders is essentially an art depending to a marked degree upon the experience of the designer, whose problem is that of determining the dimensions of a conduit that will transport the pulp within the physical limitations of the plant and in the most economical manner. This paper has been prepared in an effort to place launder design upon a more scientific basis. A method is developed from elementary principles and presented in a form that may be used directly by the designer in determining launder dimensions.. The equations that are developed are believed to represent an advance over older ones, in that they give due consideration to all the pertinent variables, either including them in the analysis or showing that they may be neglected within the limits of applicability of the equations. Experimental data from several sources are used in evaluating the coefficients that are not determined in the mathematical analysis. On the basis of the material presented, it is concluded that launders may be designed with a much greater degree of accuracy than previously believed possible, when due consideration is given to all the factors involved in the problem. However, a great deal of work still remains to be done in the laboratory before a complete answer to all the questions in launder design can be made available. HISTORY OF LAUNDER DESIGN Among the references1-11 are cited accounts of many experiments that have been conducted in an effort to advance the knowledge of the flow of liquid-solid mixtures in flumes and pipes. With three notable exceptions, this work was carried on in such a manner that the results have limited value in solving the general problem, since not all the pertinent variables were measured and controlled. The exceptions are found in the works of Blue,6 Gilbert,7 and Blatch,11 who exercised great care in controlling and measuring all the significant quantities involved in the experimentation. It is notable that much of the work done by men directly connected with the mineral industries1-4 lacks somewhat in completeness, owing apparently to preconceived notions concerning the factors that determine the flow. For example, many measurements on flow in pipes and flumes carrying liquid-solid mixtures determined only the slope and percentage of solids, with no mention of size of particles, depth of flow, roughness of channel or specific gravity of solids. Material in current handbooks8,9 and textbooks is based largely on the experimental work cited above. Although most discussions of the topic-include statements that the results to be obtained by using the data presented are limited by the fact that all variables have not been considered, it is

Jan 1, 1943

Traditional methods for the production of transition metals from their ores usually include the electric arc smelting of the ore or concentrate to produce a ferroalloy. This is subsequently refined to produce either a ferroalloy or to produce the metal or metallic carbide. Recent trends in the treatment of iron ores have seen the development of many processes for solid state carbothermic reduction followed by melting of the prereduced iron to produce steel and similar types of processes are under consideration for the production of ferroalloys. There are clear potential savings in energy and control of emissions from such processes. This paper discusses some research which is currently underway at La Trobe University into the solid state carbothermic reduction of chromium and tungsten ores to produce the metallic ferroalloy or the carbide for subsequent further processing. The kinetics of the carbothermic reduction of both chromite and scheelite were found to be dominated by gaseous CO rather than by direct carbon reduction. However the diffusion of carbon into the ore is certainly an important feature of the process. The production of tungsten carbide from the metal is the slow step in tungsten reduction. The development of phases during reduction were studied using a scanning electron microscope and an electron probe and knowledge of the phases produced allows analysis of the reduction process.

Jan 1, 1997

The Electricity Generating Authority of Thailand own and operate an opencut mine supplying coal to on-site power stations at Mae Moh, 600 km North of Bangkok. The mine is being expanded from an annual production of 1.5 million tonnes per year in 1982 to over 9.5 million tonnes per year by 1991. The mine will be amongst the largest open pit operations in the world. It is technically difficult to operate and plan due to complex geology, weak strata and surface constraints including reservoirs, forests and traditional villages. This paper presents a case study of mine planning for the above project including associated collection and processing of geological and geotechnical information. The existing operation is described, as well as the strategy adopted for the mine at expanded production. The planning covers various phases of mine planning including a Conceptual Study, a Definitive Study and detailed short term planning. Each stage incorporated new information and reflected a higher level of confidence in the data and resulting plan. Sophisticated computer techniques were required including geological modelling, calculation of volumes, geotechnical analysis, scheduling and costing. The planning was undertaken on site by a team of Australian and Thai Engineers as part of the Thailand-Australia Lignite Mines Development Project which is a four year programme of assistance funded by the Australian Government.

Jan 1, 1986