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By Ashiwani Kr Gupta

The floatability of coal is affected by the presence of dissolved inorganic ions in plant process water. Water quality is characterized in terms of conductivity, hardness, turbidity and composition of oil. These quality indices are correlated with coal flotation performance for three different water named, ?R&D laboratory tap water?, ?process untreated water? from West Bokaro wahsey-2 Tata Steel, India and ?process treated water? after passing laboratory developed treatment process. The study clearly indicated that a significant quantity of clean coal is being lost due to poor process water quality used in the flotation process. The laboratory investigations showed that if these dissolved salts and suspended solids are reduced to even 50%, a clean coal yield improvement by minimum 5%~10% at the same ash level could be expected. Therefore, the conventional practice of water recycling though a thickener or a tailings pond needs a complete re-look. The water treatment process for recycled water has also been discussed for improving the process water quality as well as enhancement in flotation performance efficiency.

Jan 1, 2014

By Boris K. Krstev

INTRODUCTION The flotation process, in the real industrial complexes, is characterized by the existence of the significant number of the close reciprocal interrelationship between the input and output Darameters. Traditional complexity is appeared with regard to absence of the suitable a priori information for the physico-chemical characteristics of the flotation process. It’s led to needful of taking of consideration about the undefinition which have got the place in the real conditions and application of the statistical methods. The identification of the flotation process through statistical methods is conception of the more-stages procedure, including the collection and previous analysis, the choice of the model structure and valuation method, the estimation of the model un- known parameters and the results interpretation. The essential concept for the subject of this paper belongs to the empirical models ("black-box") and deals with optimizing in constant industrial plant process. The offered method envisages the application of process operation data in order to improve the work process or constant accomplishment of better results for the target function in relation to the former achievement. The optimum process solution isn't afixed value under the influence of various factors, but "a moving point" along the response surface and deviates from the scheme solutions. The evolutive planning method constantly "investigates and approaches" the optimum solution for the selected target function. As a matter of fact the expert operates the plant without interrupting the normal work process. The essential concept of method is to attain changes in the standard conditions, but so limited that they will not effect either production or the product. This method is based on statistical concepts and availability of following the risk of error. The possible influental factors for the flotation process (m=l, 2, 3) is following: the metal content in the feed ore; production level (t/h); grinding fineness in the flotation pulp; pH-values; the consumption of collectors and modifiers The possible target functions are: the recovery of plant capacity, metal recovery in the concentration process and concentration quality. The application of the evolutive operativity method in the chalcopyrite flotation- Bucim concentrator, combines the statistical data and the operator's experience in the interpretation and making a decision which adds up to the precise automatic performance of the process. The advantages of this method in relation to the existing procedure for the flotation process are the following: • The method is unexpensive and losses are reduced to the time necessary to collect the data and record them in the computer. This method provides a constant process control and a quality decision which is better than those brought by an ex- pert with great experience ("hit-and-miss method"). • The method also provides incidental data about the effects. • The method should not be considered as a procedure for solving an incidental problem ("crash program"). • The obtained results must be interpreted by an appropriate expert in order to be considered instructive. MATHEMATICAL STATISTICS Taking into consideration the complexity of the enrichment processes it's necessary the application of "black-box" and mathematical modelling. The presence of the indefinite elements compel us towards the both theory of the probability and mathematical statistics. The mathematical statistics by the mineral processing investigation of the valuable raw materials in the last years has had greater signifance and widely spread application. The application of the mathematical statistics methods for the technological pro- cess analysis and the construction of the mathematical models is bound up by the task putting of the automatic control system de- sign (Fisher R. A. 1941, 1949). The statistical analysis in the enrichment processes is applied formerly, especially in the sampling estimation. Contemporary, in the last years is imposed the tendency of mathematical statistics application for the obtaining of quantity characteristics and quantity valuation from the individual influental factors. Above mentioned tendency in the significant level is based by the mathematical statistics development as a mathematical discipline close connected with the technical cybernetics general joining to the investigated object as a "black-box". Another essential factor in the mathematical statistics development is appeared the created mathematical theory of experiments as a new, to some extent, autonomous statistical domain. The theory of experiments has demonstrated exclusively importance for the investigation of the complex more-factorial processes in the chemistry, mineral processing, metallurgy etc. The investigation by the enrichment processes of the valuable raw materials and their management is possible by the statistical method application. In the same time, it's possible to use the wide-spread traditional methods of the statistical analysis, such as the methods of the dispersion, correlation, regression etc. Also, it may be mentioned above all the methods of the statistical planning of the extreme experiments. The more perspective are representatived some cybernetic methods which are based by the probability as an approach in the process analysis, for example, the identify of the ways and forms, the graph application as an additional instrument in the correlation analysis, the dynamic programming etc. The mathematical statistics application in the laboratory investigation scale is connected above all by the experimented material analysis and the compact representation of the obtained results. The mathematical statistics methods are more varrying and may be applied in the investigations of the wide circle of problems

Jan 1, 1996

By D. J. Sapsford

This paper details results from laboratory simulation of an innovative underground bioleaching process. The underground reactors are periodic flushed with recycled leachate to remove uranium that accumulates within the reactor water. This leaching cycle has been recreated within the laboratory. This study examines the influence of varying cycle protocol on uranium leaching. Protocol variants examined include variation of flushing frequency, flush volume, leachate recycle, nutrient solution (NPK) addition to reactors and Fe(III) sulphate addition to reactors. The presented data highlight the dramatic improvements in uranium recovery that might be achievable by varying the operating protocol for the actual underground reactors.

Aug 1, 2010

By H. H. McGregor

Introductory remarks by author When Mr R. C. J. Goode suggested preparation of a paper in the area of manpower utilization in South Africa, I was, while keen to accept his invitation, somewhat hesitant for two reasons. Firstly, I recognized the great difficulty of making a factual contribution, because of the lack of really relevant statistical information available, the fact that much of it is out of date, and the difficulty of researching and co-ordinating it and of evaluating a statistically sound resultant viewpoint. Experience in the actual preparation of this paper has done nothing to change my view in this respect. Secondly, it is obvious that a paper presented to a meeting of this Institute, by a member of it, would be expected to devote considerable attention to the subject in the mining industry. I am not directly employed by the mining industry, although my company has carried out extensive assignments for various sectors of it both in this country and in other parts of the world, since the 1939-45 war. I am more conscious than most of the tremendous technical and managerial skills at the disposal of the industry in this country, and consequently am equally conscious of the hazards of publishing facts and figures which might be taken to indicate any criticism of performance. I am aware that some of the information that I am about to present may indeed generate comment, and possibly even critical comment. I would like to be regarded therefore in presenting this information, as a member of the group, rather than an external critic. Under these circumstances, comment can only be constructive, and this is my earnest hope. The contribution of my paper, if contribution there is, will I hope be in the area of assessing labour productivity in mining, and in secondary industry in such a way that the performance of each against its own past results is comparable. This task has not for the present been to my knowledge attempted, and in advance I wish to take out authors' insurance against legitimate criticism from professional economists and others, by stating that I am well aware of possible short-comings in the arguments. Nevertheless I believe that under the circumstances I have, with the important assistance of several people, been able to take the subject further than has been the case in the past. Finally, I have related productivity in the mining industry and in secondary industry to a target of productivity in the Republic of South Africa. I was fortunate recently in being able to attend a series of lectures by a prominent economist in America. He introduced his subject by calling it 'A broad survey of macro-economics'. Perhaps I might be permitted to describe my paper, in the same idiom, as 'The macro-management of labour'.

Jan 6, 1970

By Evan Just

THE high standards of living and improved national security that industrialization can bring are so evident that no country can be named that does not cherish the hope of industrializing. With such a universal aim, why do many countries unable to develop their own industries accomplish so little toward attracting the foreign private investor, who alone can provide them with the necessary capital and skill? Obviously, because they fail to under- stand what constitutes a favorable climate for investment, because they have false notions about being exploited or dominated by the foreign investor, or because they are so nationalistic they refuse to permit outside assistance. The purpose of this paper is to aid the citizens and policy makers of developing countries in achieving their aims, by defining the conditions which en- courage investment and portraying the results of a policy of encouragement. The following is quoted from Eugene R. Black, president of the World Bank:

Jan 6, 1957

By P. J. Bethell

This paper reviews current fine coal cleaning circuitry, including water washing cyclones, tabling and froth flotation. It goes on to examine possible future beneficiation based on emerging technologies. Circuits considered include those incorporating spirals, fine heavy medium cycloning, hydrosizers and column flotation.

Jan 1, 1988

By G. S. Brooks

DURING the past few years, the Mineral Point Zinc Co. has had under consideration the improvement of various types of gas-filtering apparatus used in the removal of dust from crushing and milling plants, in the manufacture of oxide, and on blast-furnace fume and sintering furnaces. The original equipment of the various plants of the company was, of course, along lines of the standard stationary bag house. These houses required large surfaces, hand shaking, and varied only in the manner of the collection of solids and in the distribution of the gas. Early in 1908, the first trial of a mechanical bag house was made at Nassau Plant at Depue, Ill. The duty of this installation was on dust-laden gas from a fine-crushing mill. The Printz and Rau bag machine was finally adopted and put into operation. This ingenious machine embodied what were then to us two novel features in bag-house practice: 1. An intermittent crinkling and snapping of the filtering fabric to free the meshes of solids. i 2. A reversal of gas flow for a short period by a temporary connection w th the suction trunk. This equipment worked fairly well except in cold weather, when we ran into condensation troubles. Had we at that time understood more fully some of the limitations of fabric filtering work, these might well have been remedied. We were impressed by this experience, however, with the efficiency of sudden tension on the fabric under suction. After a study had been made of some of the Western blast-furnace houses using the reversal-of-flow feature, experiments were started early in 1914 with a view to developing an automatic equipment along the best lines of our past experience. The objects sought were: 1. Keeping labor out of the houses for hygienic reasons. 2. Reduction of labor costs. 3. Reduction in -size of hag houses. 4. Accessibility. 5. Ability to handle relatively hot gases where required.

Jan 11, 1917

By Charles E. Mergentime, J. Marshall Dean

Mergentime/Loram's extension of the Washington, DC Metro Subway System includes construction of dual 1,770-foot tunnels in soft ground, a crossover structure, a fan structure and pumping station, and other related work. This paper describes the overall construction requirements of the Contract, including subsurface conditions; Mergentime's value engineering of the tunneling and compressed air contract requirement; selection of the tunnel boring machine and backup equipment; installation of the compressed air plant; the manufacture, use and evaluation of the tunnel liners; and the tunneling performances during construction of the first tunnel.

Jan 1, 1985

By Charles D. Russell, L. H. Jenks, W. J. Leas

A detailed description is given of an experimental method for determining relative permeability of porous media to gas. Results are presented for natural and synthetic cores. The experimental data for two and three phase systems are compared. The reproduci-bility of the equilibrium gas saturation ii demonstrated and the effects due to a variation in rate of gas flow are discussed. An attempt is made to correlate total permeability and rock textural factors with relative permeability to gas. Capillary pressure curves obtained simultaneously with the relative permeability curves are shown to be equivalent to those obtained in conventional displacement cells. INTRODUCTION The advances in petroleum reservoir technology during the past decade have made increasingly apparent the desirability of a simple, rapid, reliable metliod for obtaining relative permeability data on small cores. Such data are needed in order to study fluid mechanics in porous media and for the more refined reservoir behavior prediction calculations now under development. The early experimental work in this field was done by Wyckoff and Botset1 who measured relative permeabilities for gas-liquid mixtures flowing through

Jan 1, 1950

By S. G. Tough, H. J. Hignett

The Transport and Road Research Laboratory is carrying out tunneling trials at Chinnor, Oxfordshire, with a 5-m-diam, full-face tunneling machine. The work, which is for research purposes only, involves driving the tunneling machine through chalk with most of the physical characteristics of the machine and its power consumption closely monitered. At the Conference a film was shown about this work, illustrating both the tunnel construction and the research program.

Jan 1, 1974

IT is not enough to know how to melt well and to have the bellows and charcoal for your purpose. If you wish to make small castings turn out well, on account of their thinness, it is necessary to aid the metals with unctuous and corrupting materials like tin, sublimate, arsenic, or realgar,

Jan 1, 1942

By G. F. Tagg

In an earlier paper1, the author described a method of interpreting earth-resistivity curves, based on the theoretical investigation of a single horizontal underlying stratum. If the four-electrode system of Wenner is employed, the resistivity in a homogeneous soil is given by the formula p = 2paR [1] where a is the electrode separation and R is the resistance of the earth between the two inner electrodes. If the earth is not perfectly homo¬geneous, the application of this formula gives an apparent specific resistance varying with the electrode separation. In the special case of the single horizontal underlying stratum, there is a surface layer of thickness h and resistivity pi and a lower layer, extend-ing to infinity, of resistivity p2. It has been shown by Lancaster-Jones2 that the apparent resistivity, obtained by an application of equation 1 is related to the true resistivities, the depth h and the electrode separation a by an expression of the form pa/p1 = 1 + 4F [2] where Pa is the apparent resistivity and F is a function (actually an infinite series), of the ratio h/a, and a reflection coefficient k = (p2 - p1)/(p2 + p1). For given values of h/a and k, the right-hand side of equation 2 can be calculated, and curves drawn showing the relationship between Pa/P1, h/a and k. Such a set of curves for the case when pi > P2 is given in Fig. 1.

Jan 1, 1937

By D. E. Sherwood

Mr. Tamaro introduced his paper which concerned the construction of foundations for the buildings and related infrastructure of the World Financial Center on a reclaimed shoreline site at the Southern tip of Manhattan Island. This large project presented difficult design and construction problems, both geotechnical and structural. All structures were supported by foundations carried to rock. Two of the buildings were supported by conventional pier (pad) foundations constructed within diaphragm wall cofferdams. The remaining structures were supported by either piles to rock or caisson (large diameter) piles with socket depths drilled through the rock of up to 7.6 metres. Underground services, railway and proposed road tunnels all affected the installation of foundations. The proposed road tunnels for the new six lane 'Westway' would involve an excavation 12 metres deep adjacent to and under three buildings. This problem was solved by an agreement that tower windloads would be taken by the tower foundations and not distributed through the basement walls. This was achieved by a system of battered caissons founded on the rock and arranged so that adjacent caissons were founded in different rock masses. Diaphragm walls were restrained using tie backs. Ground testing indicated an exposure to D.C. stray current corrosion of all underground construction. As a result all of the foundations were isolated from the ground by non-conductive materials. In the case of piles and caissons the reinforcing for the caisson was fully protected by concrete and all outside steel used for the installation of piling was considered sacrificial and not used in the computation of long term load carrying capacity.

Jan 1, 1991

By T. W. Johnson

One of the common methods of increasing recovery of oil from partly depleted oil sands is to inject natural gas, air, or air-gas mixtures into the sand, thereby supplying energy to move oil into the well bore. Where natural gas is not available, air or an air-gas mixture is used as the repressuring medium. Air-gas mixtures are obtained from the casing-heads of oil-producing wells in the areas repressured with air or air-gas mixtures and consist usually of varying amounts of the hydrocarbon gases, nitrogen, oxygen, and carbon dioxide. Laboratory experiments have been conducted by the Bureau of Mines to determine the effect of air on crude oils.4/ In these experiments the crude oils were oxidized by the air, and the degree of oxidation depended not only upon the chemical composition of the crude oil but also upon the duration and method of contact between the oil and air, the temperature of the fluids and the concentration of the oxygen. When the crude oils were oxidized the following results and changes in the oils were obtained:

Jan 1, 1937

By P Holtham, K C. Runge, E Tabosa

Traditionally, comminution and flotation have been surveyed, analysed and optimised separately. This often results in less than optimal outcomes because of the complex interactions between the two processes. Flotation recovery is a strong function of the valuable mineral particle size distribution with lower recovery of ultra-fines due to poor flotation kinetics, optimum recovery for the intermediate sized particles and lower recovery for the coarser particles due to poorer liberation. Thus, to optimise flotation recovery and grade it is usually best to grind to a fine size. This requirement needs to be balanced by the cost of grinding finer and the revenue that results from an increase in grinding throughput, which often results in a coarsening of the flotation feed.This paper demonstrates a technique which can be used to predict the effect of a change in feed grind size on flotation performance. It can be used to determine the optimum grind size for a particular operation which optimises total circuit profitability. Analysis is relatively easy to perform, as a minimum, requiring only size by assay data of the feed and product streams of the process. Case studies will be presented that demonstrate the usefulness of this technique in feed grind applications. Potential use of the technique for regrind evaluation is discussed. The limitations associated with this technique in certain circuit scenarios will also be outlined.CITATION:Runge, K C, Tabosa, E and Holtham, P, 2014. Integrated optimisation of grinding and flotation circuits, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 77–84 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By David Russell, Courtland Lee

FOREWOHD-Americans have been able to create wealth from the nation's natural resources to an extent unprecedented in recorded history, thanks largely to the existence of a free market and of a rational body of laws. The General Mining Law of 1872, for instance, by establishing the rules of the game, was quite effective in channeling the ability of Americans to discover and develop mineral deposits. Another example was the Mineral Leasing Act of 1920 which made available the more easily discovered mineral deposits by spelling out the conditions and rules under which miners could obtain leases on federal lands.

Jan 5, 1977

By C. Tsatsanifos

Following closure of an old asbestos mine in Zidani, Kozani Prefecture, Greece, the geotechnical and environmental restoration of the tailings slopes was required. The geotechnical aspects of the restoration included the formation of gentler slopes to increase stability, in combination with drainage works for the same purpose. The environmental aspects of the restoration included covering the slopes with successive layers of soil in order to minimize infiltration of rainwater, and hence the potential for further transport of asbestos fibers, and to provide a suitable layer for revegetation of the slope. The paper presents results of slope stability evaluation using both limit equilibrium and finite element analyses and raises some issues related to reducing impacts to the geoenvironment when designing such restoration projects.

Jan 1, 2006

By Conrad W. Stellar, John L. Paynich

Abstract-A Design/Build concept that provides for earliest possible completion and lowest cost is presented. Elements of the program include: joint cooperation between owner, designer and builder; schedule construction sequence; and a line budget. Benefits over lump sum contracts are reviewed.

Jan 11, 1978

By Robert B. Hopler

Emplacing explosives in the borehole by bulk methods is utilized today for about 35% of all of the explosives used in the United States. Although different from today's methods, some bulk emplacement has been utilized throughout the history of explosives. This paper provides an overview of the evolution of the industry from primarily packaged to primarily bulk materials and methods.

Jan 1, 1992

4.5.1 General The provisions of the article shall apply to the design of axially and laterally loaded driven piles in soil or extending through soil to rock. 4.5.1.1 APPLICATION (Revised Article 4.3.1.1) Piling may be considered when footings cannot be founded on rock, or on granular or stiff cohesive soils within a reasonable depth. At loca-tions where soil conditions would normally permit the use of spread footings but the potential for scour exists, piles may be used as a protection against scour. Piles may also be used where an unacceptable amount of settlement of spread footings may occur. 4.5.1.2 MATERIALS Piles may be structural steel sections, steel pipe, precast concrete, cast-in-place concrete, prestressed concrete, timber, or a combination of materials. In every case, materials shall be supplied in accordance with the provisions of this Article.

Jan 1, 1989