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By J. D. Patsey, G. T. Lineberry

Introduction A computer program was developed for analyzing drum-type hoists before modifying an existing system or designing a new one. Its use permits the preliminary evaluation of a system before seeking technical assistance from mine hoist designers and manufacturers. The user-friendly program accepts a variety of data and analyzes hoisting systems for any balance state. The program can be used to calculate skip capacity to yield a desired production rate, solve for drum face width, select a permissible wire rope, estimate total horsepower of the hoist plant, and estimate annual power cost. Whether required for a large mining complex or for a relatively small operation, a hoisting system must be carefully designed to ensure the efficient, reliable, and safe flow of material. Because shaft sinking and hoist installation can total between 2.5% and 3% of the cost of opening a deep mine, proper hoist selection is critical. Today's mining engineer has at his disposal the most powerful design and analytical aid ever, the microcomputer. There is, unfortunately, limited software for the study of hoisting systems, unlike that for other materials handling equipment (Manula and Albert, 1980; Prelaz et al., 1964; Bucklen, 1969; Thompson, 1985). HOIST reduces a time-consuming set of calculations to a concise package of interrelated subprograms. A literature review revealed no common-user programs to analyze hoisting systems, although at least four major hoist designers/manufacturers/installers have their own in-house programs. To provide a tool with which the mining engineer could preliminarily analyze a materials hoisting system or could check the calculations of a hoist contractor, a computer program was developed. HOIST was written in BASIC for the IBM-PC for ease of program adaptation and to encourage field use on compatible systems. Details of program development are omitted, since the basic principles of hoisting analyses are relatively straightforward, simple, and readily accepted (Harmon, 1973; Nordberg, n.d.; Adler, 1957). Program features, intended usage, and benefits of the computerized solution are emphasized over theory development and mathematical rigor. Background The mine hoist system that is selected and installed at a mine is the "lifeline" of that mine, with installations lasting 20 years or more. Thorough study is warranted to ensure that productivity demands are met at a minimum cost per ton. The increased cost of a large, powerful, high-speed hoist must be offset by increased production to justify its selection. To optimize this tradeoff, an extensive hoisting analysis should be performed. The analyses to properly size the skip (or cage), the drum, and the hoist drive are conducive to computerization, permitting rapid evaluation of changeable operating and design parameters, such as velocity, acceleration, state of balance, and productivity demand. The program is particularly useful in conducting sensitivity trials, such as investigation into the effect of change of productivity on skip capacity and on horsepower of the hoist drive. HOIST is currently limited to the study of drum-type hoists with cylindrical drum(s). However, only minor changes to the program would permit analysis of friction hoists and conical drum configurations. Model development and testing The program is based on accepted equations and physical relationships. Examples of manual calculations formed the basis for decision points and program branching. Data is input in the order that it would be needed if the problems were solved manually. The choices are arranged likewise. HOIST was developed in sections, with manual solutions performed to check program logic. The testing became more rigorous as sections were completed. Output from one section becomes input for following sections, as appropriate. The simplified flow diagram of HOIST is given in Fig. 1.

Jan 2, 1987

By S. Uludag

Spontaneous combustion of coal has been studied by laboratory techniques using an apparatus in a small-scale laboratory testing. Coal?s inherent characteristics can be measured using Differential Thermal Analysis (DTA) and Crossing Point Temperature (CPT) methods. The DTA curve obtained after testing is compared with actual inherent moisture and its effect on spontaneous combustion has been investigated. It has been found that the Wits-Ehac Index increases as the inherent moisture of the sample increases. Therefore it can be deduced that liability to spontaneous combustion increases with increased inherent moisture. In addition, volatiles have a catalytic affect on self heating immediately after the inherent moisture is reduced. This is identified as stage two in the thermogram. The inherent moisture has a cooling effect during the initial stages of testing and is visible in the DTA thermogram. In addition, while an increase in carbon content means an increase in Wits-Ehac Index value, an ash content decreases the likelihood of on spontaneous combustion. Keywords: Spontaneous Combustion, Differential Thermal Analysis, Crossing Point Temperature, Moisture, Coal, Laboratory Testing.

Jan 1, 2007

By Hwasoo Park

Keywords: FC mold, Argon, Magnetic, Solidification Fluid flow plays a significant role for steel surface quality in continuous casting. Although water models are able to model fluid flow, the flow pattern is not of practical interest since the moving solidifying shell cannot be accounted. Computer modeling has become a popular and dependable tool to analyze the complex phenomena occurring in continuous casting. In this numerical simulation we coupled momentum and energy equations considering the solidification of steel along with turbulence ?-e model. The vertical bending mold is equipped with bifurcated nozzle with 15 degrees of port angle. FC mold is supplied with DC induced magnetic fields. Influence of argon and magnetic fields on molten steel flow and heat transfer is investigated by solving momentum equations adding source terms due to multiphase ? magneto hydrodynamics. The results show that magnetic fields reduce the jet velocity from port by lower magnetic core induced field but the influence on meniscus velocity is complex to describe. Magnetic fields increase surface temperature and homogenize its distribution on surface and inside a mold.

Jan 1, 2005

By R. Colás, A. Salas, M. P. Guerrero Mata, R. Garza

"The use of the finite element method (FEM) for studying the plastic behavior of metals has become a common practice over the past few years, because it has been proved to be a good means of evaluating processes parameters, and predicting and improving processes, avoiding the traditional trail and error technique. FEM was used via a commercial package (Abaqus) to create two dimensional models to simulate uniaxial tensile tests for a galvanized low carbon steel. The aim of the work was to analyse the plastic behaviour of a distribution of grains on the zinc cover of a set of galvanized low carbon steel samples. A mesh with lines 2 mm apart was drawn on one of the faces of the samples that were deformed at room temperature, at constant crosshead speed, stopping the deformation at different times. Before and during the stops the deformation measurements were recorded for further calculations in an image analyser in order to compare these with computational predictions, as well as validate the numerical model. The results of this study can be extended to other testing conditions, besides the model can be used for obtaining constitutive equations of the materials.INTRODUCTIONThe use of the finite element method has been widely spread during the last two decades in most engineering areas, it is a good means of obtaining approach values at a first try [1-4]. Thanks to the software and hardware developments it is now possible to run huge problems within hours or minutes, making the technique more accessible and useful for the industry.The aim of this work is to create a finite element model for the uniaxial simple tension test, and compare the results with some experimental results, and asses the validity of the model.The plastic behaviour of the materials with FEM has been studied for a long time [5] and there is always something new to learn about this behaviour of the metals in particular, as well as to characterized new materials and alloys [6,7]. The tension test has been used since XIX century to get knowledge of the materials [5,8], it is the test that has been used the most and the only that is fully standardized, although it has the limiting of low strains, it is still the most widely used, especially in the industry.Two different finite element models in two dimensions (2D) have been developed, one called the mesh model and the other one the grain model, attention was focused on the geometry and strain prediction. The model is validated with experimental test, by using the data and directly comparing it with the numerical predictions. All the tests were carried out at the same constant crosshead speed at room temperature. An analysis of the grid distortion using FEM and analytical methods has been carried out."

Jan 1, 2001

By Sanchita Chakravarty, Sumantra Bhattacharya, Divya Jyoti, A. K. Mukherjee, Soni Jaiswal

"Release analysis is independent of collector and frother dosage and type, but it is primarily influenced by the degree of liberation or “state of release of the sample”. The shape of release curve is an indication of the degree of liberation. This paper briefs about the effect of reagent combination, particle size and surface characteristics on the release analysis of difficult-to-clean LVC coal.Release analysis of three LVC coal fines obtained from two different coalfields of India was carried out at three different size levels such as -0.5mm, (-0.5+0.1) mm, and -0.1mm. The collectors used were n-dodecane and commercial diesel oil. Incomplete liberation of coal fines even at a size of -100µm, corroborated by photomicrographs of ROM and clean coal macerals, in a great measure reduced the flotation-based cleaning potential of the fines. FESEM images of fines reveals that the adherence of ultrafine onto the surface of relatively coarser particles reduced the clean coal recovery. The results obtained also appear to be coal, reagent combination and, particle size and particle surface specific. Only one coal indicated the liberation as is usually expected for -0.1mm particles with a reasonable yield of 65% at 18% ash. INTRODUCTION Froth flotation has a long history of being used to treat coal fines. Coal flotation is considered to be difficult, if the percentage of Near Gravity Material (NGM), i.e. essentially locked particles, in flotation feed is >10% [Aplan, 1993], which is usually the case with all the coking coal fines in India. The fines are rich in vitrinite, so valuable for coking coal. Unfortunately, there appears to be no standard procedures to determine the separation efficiency of froth floatation. Release analysis proposed by C.C. Dell in 1953 [Dell, 1953], aimed to determine the ultimate floatability of coal. Several other techniques had been proposed but release analysis technique has been considered to be a vast improvement over the batch flotation process [Forrest et al. 1994]."

Jan 1, 2018

By P. R. Hanes

A description of the methods used in driving two tunnels, 2 miles long each, one a 9-ft. and the other a 19-ft. diameter section, for the Owyhee Irrigation Project, Oregon. One heading of the smaller tunnel was driven 1315 ft. in 73 shifts in one month and 10,966 ft. of this section completed in ll½ months using two shifts for eight months and three shifts the rest of the time. This is a good illustration of the proper use of a mechanical shovel and the importance of careful selection of supplernentary equipment to secure best results. Large cars, speedier and heavier locomotives, 36-in. gage track of 45-lb. rail, and a good switching method increased actual shoveling time and cut down muck removal period about 45 minutes from average. The larger tunnel, after trying out standard electric revolving shovels of both the rail mounting and caterpillar tread types, was excavated with a mechanical mucker. This is the first time that a tunnel of so large a section has been handled this way. This record work was accomplished without drill carriages.

Jan 1, 1934

By L. D. Jayaweera, R. G. Robins

The pocessing of gold bearing sulphide minerals wr ich contain arsenopyrite and other complex arsenic sulphide minerals results in arsenic containing emissions and effluents which must be given careful consideration in relation to clean air and clean water standards. The sources of arsenic and the various process options for treating arsenical gold ores and concentrates are briefly reviewed. The problem relating to the removal of arsenic from gaseous emissions from roasting processes is considered. Residues from aqueous processing contain a variety of arsenical materials which have not been characterised, and the long-term stability of these is suspect. 'rhe use of lime to stabilise aqueous residues as either calcium arsenate or calcium arsenite has been shown to be inadequate for long term disposal since both compounds are converted into calcium carbonate due to the influence of carbon dioxide in the atmosphere. Ferric ion solutions have been used to precipitate ferric arsenate or to form ferric hydroxide which binds the arsenic for short term disposal, The long term stability of these ferric materials is poor, but could lead to the acceptance of a slow release option rather than complete containment of residues.

Jan 1, 1991

Our merchant marine is rapidly outgrowing our consular service, according to Edward N. Hurley, Chairman of the United States Shipping Board, who urges that steps be taken immediately to provide facilities abroad for handling the millions of tons of shipping which will be afloat under the American flag in peaceful trade when the war is over. When peace is restored and our present tonnage is scattered over world trade routes, the consular service will be inadequate to handle our ships: Besides, it will have to work against the handicaps of obsolete shipping regulations and, in many cases, lack of experience. There are nearly 100 pages in the United States consular regulations dealing with shipping platters. . Many of these regulations are based on old treaties and many of them are obsolete. There are also differences between treaties with various countries. Our consuls often lack authority to handle matters involving the interests of our sailors and shipowners. Before we can operate a modern merchant marine we must revise, standardize, and simplify this whole mass of regulations and bring them up to the efficiency of other nations' practice.

Jan 12, 1918

By Frank Ladwig, Stephen Gos

Tailings and/or wastewater generated from gold extraction plants employing cyanida­ tion must often be treated to remove the cyanides and heavy metals for environmental reasons and/or gold extraction inhibition reasons, due to the presence of heavy metals like copper, which have a detrimen­ tal effect during cyanidation. In recent years, the treatment of effluents contain­ ing cyanides and heavy metals has been widely studied, Among chemical treatment methods, the use of hydrogen peroxide has been universally employed as a viable option. However, in some cases, effluents containing high concentrations of heavy metals and/or solids decompose the hydrogen peroxide, an undesirable side reaction. The addition of stabilizers or other peroxygen compounds together with hydrogen peroxide can, however, considerably reduce the rate of decomposition and thus result in detoxi­ fication costs, which are considerably less than the standard detoxification process using hydrogen peroxide. In some cases, the reaction rate can also be increased, resul­ ting in lower investment costs for new detoxification plants. This paper deals with the results of developmental work performed in the recent past and introduces some new processes with the aim of optimizing reagent consumption and costs.

Jan 1, 1992

By A. Santha Ram

The Indian Mining sector is subjected to a number of trends including call for global transition towards the route to sustainable development. Several regulations were enacted by the Government departments, from time to time, in order to identify the problems faced by the mining industry, including small-scale mining operations and to suggest appropriate mitigation measures in the form of environmental standards and certifications. During this process, a pursuit of sustainable development is regarded as an important area responding to socio-economic conditions, priorities and thus guides eventually corporate policies and practices. Thus, there is a need to formulate strategies for sustainable development. Based on these strategies some environmental indicators were developed in order to track down the progress and to evaluate its success. A case study pertaining to a group of iron ore mines in North Goa and Chromite mines in Sukinda, Orissa was selected for this study. Base line environmental data has been generated in the respective study sites. A core set of environmental indicators monitoring environmental progress based on the P-S-R model pioneered by OECD is linked with indicators for assessing the integration of environmental concerns.

Jan 1, 2003

By G. E. Joe

"This is a panel discussion on the milling experience with large volume flotation machines in Canada. Over the past ten years, the Canadian milling industry has been characterized by treatment of ever increasing tonnages of lower grade ores. In order to treat these ores efficiently, mineral processors have been employing increasingly larger volume flotation machines. In older established mills, standard flotation cells have been replaced by the larger volume models with very apparent savings in mill floor space as noted in the Opemiska copper mill.We are pleased to hear from four mill operators with extensive experience on large volume flotation machines. They are:1. I. E. Wahn, metallurgist with Falconbridge-Manibridge, who will describe their mill experiences with the Tank cell and the Maxwell cell.2. G. M. Hughes, mill superintendent of Sherritt Gordon-Ruttan, will detail recent experience with the Agitair cell.3. J. R. Maxwell, mill superintendent of Opemiska Copper, will report on their Maxwell cell installation and operation.4. A. H. Winckers, superintendent of Development and Technical Control, Sullivan Mill, will present a paper written by H. J. Chalmers describing Cominco's past experiences with large volume flotation machine installations including Denvers, Wemcos and Maxwells."

Jan 1, 1974

Today's emphasis on the enterprise bargaining process must be seen as an opportunity for organisations to further develop occupational health and safety standards at work. In particular, this shift from a centralised industrial relations system to employer, employee bargaining, presents organisations with an excellent opportunity to develop OH & S at the `shop floor' level. This is despite real difficulties in presenting hard data on the cost benefits. Unfortunately, examination of enterprise agreements ratified by the Australian Industrial Relations Commission (AIRC), show that less than 32 per cent contain provision for occupational health and safety. Those addressing the issues of occupational health and safety have included segments such as: ò rehabilitation activities; ò a new emphasis for workplace occupational health and safety committees; ò formalising procedures related to hazard identification and control; ò the use of personal protective clothing; and ò occupational hygiene and health monitoring issues. For example, an enterprise agreement reached between CIG-Gases and their unions, included clauses which commit employees to attending ten safety meetings and two work place inspections each year, in order for them to receive any further pay rises.

Jan 1, 1995

At a meeting of the Associated Engineers, with Columbia Section in charge, a discussion of the metric system was led by-Mr. F. A. Ross. While the majority of the engineers present favored resolutions seeking compulsory adoption and use of the system at the end of 1924 it was believed the engineers present should not undertake to speak for the entire membership and upon suggestion of Mr. J. B. Fisken the resolutions were laid over to be acted upon at a later meeting. The resolutions are as follows: WHEREAS the Great War has drawn the United States into a permanent and close relationship with the other nations of the world and opened the way to an unlimited foreign trade; and WHEREAS more than-70 per cent. of all nations have discarded their arbitrary standards of weights and measures and have made the use of the decimal, or metric, system obligatory; and WHEREAS the United States still clings to an antiquated, complex, cumbersome, and wholly illogical system of weights and measures, consisting of a duodecimal and fractional arrangement of arbitrary units, instead of definitely determined and correlated units following the decimal system; and

Jan 8, 1919

A. K. McCosh, Coatbridge, Scotland (written discussion*).-It is well known in Great Britain that oven operators in the United States have been able to reduce the coking time much below European standards by the employment of higher temperatures. Our linings have always been the factor that has prevented our doing the same, and it would be of much interest to coke-oven operators here if Mr. Blauvelt would give a typical analysis of the bricks his company uses for the linings of its ovens, and if he could see his way to send me a sample so that I could have the texture examined, I should personally be very much obliged. The lining brick which my company has found most successful is of a ganister variety, and has the following analysis: Silica, 80.8 per cent.; alumina and iron oxide, .17.8 per cent.; lime, 0.8 per cent.; magnesia, 0.07 per cent.; but with this brick the least carelessness on the gas regulator's part may destroy the lining. It would also be of interest if Mr. Blauvelt could give the temperatures of the air leaving these generators and also of the oven flues.

Jan 10, 1918

The paper sets out the context for water and the challenges that have to be faced in the battle to alleviate global poverty. It acknowledges that the world has been blessed with abundant water but because of population and development pressures, and the projected changes in climate, avoiding serious water shortages in some places will be difficult. MiningÆs use of water is placed in context and the paper then considers the specific threats to the industry in terms of availability and price and the need to find mechanisms to deal with the issue of resource degradation caused by abandoned mines. Rio TintoÆs use of water is then set out and three examples are given of how different water challenges have been addressed. The paper goes on to consider each element of a water strategy designed to move Rio TintoÆs performance towards excellence. This strategy incorporates improved management procedures (policy, principles, standards and targets), performance enhancement (through use of the Rio Tinto Water diagnostic and technology changes) and working with others in the academic and NGO community who seek to address the same global issue.

Jan 1, 2003

By G. C. Stone

AS the term "hardness" is used with many different meanings, it should be understood that it here means resistance to deformation by compression. It was determined by measuring the pressure, in pounds per square inch, necessary to reduce by 20 per cent., the length of cylinders 1 in. (25 mm.) in diameter by 2.6 in. (66 mm.) long. The tests were made at Columbia University on an Olsen 400,000-lb. machine, the load being applied at a constant rate of speed 0.0319 in. per min. The results were obtained by Messrs. Rigg and Williams, and some of them were given in a paper read at the Sixteenth Annual Meeting of the American Society for Testing Materials, in June, 1913. The remainder of the results were obtained in subsequent experiments by the same authors. In all cases, the results given are the averages of three or more closely concordant tests. All of the spelters tested were of standard commercial grades and all were of compositions making them good deliveries. The accompanying table gives the results arranged in the order of increasing hardness:

Jan 1, 1919

Meeting of June 26, 1914.-The President was authorized to appoint Advisory Committees to co operate with the United States Bureau of Mines. The President announced the appointment of Edward H. Benjamin and W. C. Ralston as additional members of the Committee on Arrangements for the San Francisco meeting, 1915. H. T. Van Ells and Judd Stewart were appointed to represent the Institute on a joint committee of several technical societies to consider the standardization of graphical methods for the presentation of statistics. The President announced the appointment of H. Foster Bain to succeed Edward H. Benjamin, resigned, on the Committee of Management of the International Engineering Congress, 1915. The Secretary was authorized to issue a new circular advertising the sale of back Transactions and to sell back Transactions, bound in cloth, at a price of $35 for 46 volumes, provided sufficient orders were received to warrant the special binding. The sum of $177.50 was contributed to the San Francisco Local Section. Upon recommendation of the Committee on Membership, 70 Members, 4 Associate Members and 7 Junior Members were elected to their respective classes; there was also one change of status from Junior Member to Member.

Jan 8, 1914

By Serge Vézina

Environmental issues have evolved considerably over the last two decades. The main contributing factors, to name a few, have been the changing values of our modern societies, the globalization of trade and its linkage to environment, evolution and accessibility of information/communication technologies, better educated populations, climate change, long range transport of toxics and the increasing influence of NGOs and multistakeholders. As well, environmental management of mining operations had to be realigned in order to meet these new realities and to respond to more elaborated regulations oriented towards sustainability. Environmental Management Systems (EMSs) have emerged and have been introduced to meet not only the assurance of conformance to regulations but also to prevent pollution and to apply the continuous improvement of mining processes. EMS models have been developed and certification to international standards (e.g. ISO-14 001) is a common practice. Globalization has imposed challenges and additional requirements to environmental management. Developing a mine in emerging countries implies dealing with international agencies, local communities and a variety of government infrastructures to obtain a ?licence to operate?. This paper presents the structure of our EMS and how we have adapted its implementation to our operations in South America.

May 1, 2003

Rougher Cells The photo shows one of three carloads of new Denver Equipment Co. rougher flotation machines destined for a single customer. [ ] Low level froth overflow on both sides, and double impeller mechanisms in an open-flow type tank, were designed to enable control of variable conditions in the rougher circuit for better metallurgy. Intense agitation and aeration are claimed, for effective recovery of low-grade mineral particles. Standard parts are used, interchangeable with regular Denver Sub-A units. The Super Rougher is now in production and a 2-cell No. 24 machine will be displayed at the Mining Show. Circle No. 1 Fans A line of industrial fans built for air or materials handling is available in eleven sizes from 670 to 44,000 cfm capacity from Westinghouse Electric Corp. The air hand¬ling wheel has backwardly-inclined blades. Circle No. 2 Trolleyphones The Femco Trolleyphone, plug-in model, 2550 series, is offered as a simple mine or mill communications system by Farmers Engineering & Mfg. Co. More compact, easier to install and service, the new model is powered from existing trolley wire or power line. Circle No. 3

Jan 1, 1952

By G. A. Achilleos

The insufficiency of Boolean Logic and ?hard? decision making to represent and manage spatial data in set with their spatial errors comprises a remarkable difficulty for widely accepted estimation procedures, in realistic planning of space geometric problems and management through a GIS. Fuzzy logic as well as other theories such as the theory of Probabilities, Bayesian theory etc., contribute substantially towards this direction. Data are accompanied by their accuracy and are managed through the applications and modules of Spatial Analysis, aiming to access a decision with known accuracy and fuzziness. As it concerns the cases of waste sanitary landfill sites designing, which are based on the construction of a bank, the problem shown by this paper, seems to be quite serious. The determination of the theoretical waste disposals body in the landfill is based on an uncertain Digital Elevation Model (DEM). As this model is a result of a procedure enclosing errors and inaccuracies, it is for certain a non - error free model. Thus, the geometric computation of the excavation quantities and the waste disposals solid body volume, misquotes the expected standard theoretical computation and imports the need to decide and set a risk level for the project.

Jan 1, 2005