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By I. K. Chopde, M. M. Dhobe, C. L. Gogte

"The quality of machined surface is becoming more and more important to satisfy the increasing demand of component performance and its reliability. While machining any component, it is necessary to satisfy the surface integrity requirements. Heat treatment plays an important role in improving the characteristics of the material.This work investigates the effect of heat treatment on the surface characteristics of AISI D2 tool steel after Wire-Electro Discharge Machining (W-EDM). The test specimens were prepared by hardening and tempering and then machined with Wire-Electro Discharge Machining process. Optical and scanning electron microscopy, surface roughness and micro hardness tests were conducted to study the surface characteristics of the machined surface. After characterization based on microstructures and test results, it is observed that the recast layer droplets are of smaller size with reduced white layer thickness resulting in higher hardness and lower surface roughness.IntroductionWith the development of mechanical industry, the requirement of alloy materials having high hardness, toughness and impact resistance is increasing. At the same time the quality of machined surface is becoming more and more important to satisfy the increasing demands of component performance and reliability. When machining any component, it is necessary to satisfy the surface integrity requirements. Surface integrity has two important parts. The first is surface texture, which governs mainly surface roughness. The second is surface metallurgy, which concerns to the nature of surface layer produced in machining [2]."

Jan 1, 2012

By G.A Subagyo

The condition of slag in a pyrometallurgical reactor is vital to ensuring control of the process. A new technique based on multivariate image analysis (MIA) of digital images has been developed to provide an online measurement of important slag characteristics, such as the presence of exposed metal, the presence of solid phases, and temperature. This paper shall describe the technique and provide some results from analysis using industrial plant data.

Jan 1, 2003

By Eugie Kabwe

The velocity of detonation (VOD) is a significant property considered when rating an explosive. It may be quantified as a confined or unconfined velocity. The confined velocity is the rate at which the detonation wave propagates through an explosive within a blast hole or any restrained space. The unconfined velocity emanates when an explosive is detonated in the open. However, the confined velocity is more significant as explosives are usually employed under a definite degree of confinement. This paper evaluates the increment of air deck volume and its effect on the VOD. The air gap (air deck) volume is increased stepwise from 10 to 30% of the total blast hole volume by reducing the stemming height in the collar zone. Thereafter, the VOD estimation in the 172-mm-diameter explosive column is conducted using the Dáutriche technique. It is observed that the VOD reduced with the increasing air deck volume and detonation failure is high when 30% of the blast hole volume is replaced with air deck. It is deduced that the increment of the air deck volume has an effect on the attenuation of the steady-state VOD.

By C. A. Pearson, W. D. Dietzman, M. E. Hawkins

Results of chemical analyses and electrical resistivity measurements of 422 samples of oilfield brines from 120 east Texas fields in Railroad Commission of Texas Districts 5 and 6 are presented in tabular form . These samples represent water from all of the major petroleum- productive formations in the area . Water analyses and electrical resistivity data , when fully utilized by proper study techniques , are useful tools in the solution of many engineering problems such as detection of well leaks , identification of water sources , and interpretation of electrical well logs . In the area included in this study , these representative data should facilitate the solution of problems in which water analysis and water resistivity are factors .

Jan 1, 1964

By Maurício Covcevich Bagatini, Maycon Athayde

Nowadays, the HPGR (high-pressure grinding rolls) is an intermediate step between filtering and balling in the most modern iron ore pelletizing operation. The operation debottlenecks filtering process and reduces pressure over the typical milling process to control particle size to the balling. The present study evaluated aspects of microwave application to the iron ore concentrate fed to HPGR in a bench scale unit. Iron ore concentrate was irradiated varying the microwave exposure time and grinding efficiency was evaluated. The moisture influence in the HPGR efficiency was also assessed. The pellet feed blaine surface area (BSA) improved by 300 cm2/g and % < 325# fraction by 3%. Scanning electron microscope (SEM) images show the formation of micro-cracks onto the particle surface induced by microwave; the effect observed helped improve the milling process performance, in addition to the moisture reduction observed due to the temperature increase.

By S. A. Vazhnov, A. G. Kalimov, A. A. Potienko

In this paper we describe a mathematical model of the magnetic field and magnetohydrodynamic processes simulation in aluminum reduction cells developed in St. Petersburg State Polytechnic University, Russia. The model includes: (a) calculation of the currents in the busbar system and inside the aluminum cell construction elements including cathode and anode structures, aluminum and electrolyte layers; (b) magnetic field simulation using the integral equation method; ( c) investigation of the magnetohydrodynamic characteristics on the basis of a shallow-water approach. The developed model was used to investigate operational characteristics of the different industrial aluminum cells. Calculated magnetic field distributions and MHD stability parameters were compared with the available experimental information; the comparison demonstrated a reasonably good agreement.

Jan 1, 2006

By P Ottenio, B CarrT

In the last 40 years, the froth flotation process widely spread in the paper industry becoming the dominant technology for ink removal from recovered paper slurries and cellulose fibres recovery. Most of current models used to describe the flotation deinking process are based on hydrodynamic and statistical theories of ink particles collision/attachment to air bubbles. The complexity of these theoretical models, together with the variability of the recovered papers composition, does not allow to define a set of æeasy to handleÆ equations to be used for modelling industrial flotation cells. This main limiting aspect makes that, in several deinking process modelling tools, basic parameters used to characterise the flotation unit, ie yield, ink removal efficiency, water loss, are constant parameters. Although in some process simulation tools the flotation yield/efficiency is adapted to process control parameters (air ratio, pulp flow, pulp consistency), physicochemical variables (namely the pulp frothing aptitude, the pulp surface tension and the ink adhesion energy to air bubbles) are not taken into account to adjust the flotation yield/efficiency. Data collected during recent laboratory and pilot plant experiments focusing on the role of surface active substances on the flotation efficiency were therefore interpreted and used to identify general trends that could be described with simple semi-empirical models. A set of model equations using surface tension and froth removal height as main variables was then defined in order to describe the behaviour of a pilot flotation cell. Trends obtained during the dynamic simulation of the deinking pilot plant were in good agreement with experimental data obtained under similar experimental conditions, thus indicating that developed equations can forecast with good approximation the behaviour of a flotation deinking unit.

Jan 1, 2005

Aberfoyle sought to reduce Hellyer project development risk to a greater degree than usual. Consequently the ore reserves estimate and feasibility study were particularly comprehensive. A detailed ore reserve study was completed based on extensive drill core and underground sampling, large scale pilot plant work and a detailed feasibility study. Leading external consultants were used for advice on commercial matters which impact on ore reserves and to audit major technical conclusions, including the results from pilot plant work and the ore reserve estimate. Other project risks were diminished by negotiating a State agreement covering security of title, royalty formula and environmental management procedures, by obtaining sales contracts, and by analysing Hellyer&apos;s position on an industry cost curve. The task of financing the project was much simplified by the extent and quality of information available from the ore reserves estimate and feasibility study report.

Jan 1, 1990

By Charles Goodeve

"BEFORE I begin, I should like to thank The Canadian Institute of Mining and Metallurgy for the honour they have bestowed in inviting me to give this address at the fourth annual C.I.M. Conference of Metallurgists banquet.Secondly, I should like' to convey the greetings of the Iron and Steel Institute of Great Britain in accordance with a request made by its Council at its last meeting. The I.S.I. hopes for the continued growth in strength of this annual Conference and in the collaboration between our respective societies.When I read the program of this Conference, it was brought home to me what a non-ferrons country Canada is. Also, I realized what enormous advances have been, and are being made, and what an ex-citing field non-ferrous metallurgy is for the scientist. This made me wonder, as I have done before, whether the future for steel was proof against these advances.At present, iron and steel stand astride the metallurgical world like a Colossus; I hope that the bronze industry will pardon my stealing their thunder and mixing my metaphors! Will this still be so in the future?The best way to answer this question is to take a look at the fundamentals to see why the iron atom dominates to such an extent that al! other metals are called ""non-ferrons."" Is its present position due to historical and therefore ephemeral reasons, or is there a fundamental difference between the atom of iron and those of other metals?"

Jan 1, 1966

By Jan Knobloch

Inter Stand Cooling (ISC) can increase productivity of a HSM and improve final mechanical properties of the strip. Constant Target Exit Temperature can be ensured for the whole strip length eliminating skid marks and other temperature oscillations of the transfer bar. The paper deals with advanced control module of ISC. Essential mathematical models of the control system is introduced and basic functionality is explained. Temperature model is based on FEM. Mechanical and thermal properties of the strip are calculated from chemical composition using neural network. Further on an experimental possibilities for investigation and design of ISC cooling headers will be shown. In conclusion practical experience with ISC on various HSM will be discussed.

Jul 30, 2018

By Jürgen Antrekowitsch, Thomas Griessacher

"Heavy metal containing residues are typically hazardous wastes because on the one hand, a deposition gets more and more complicated and on the other hand, the large amounts of metals like Zn, Cu, Fe and Pb represent a significant value. Thus, a post-treatment of these materials with the recovery/recycling of the metals and stabilization of the waste is not only ecological but often also economical. The therefore typically applied recycling processes utilize pyrometallurgical steps, where carbon or carbon monoxide from fossil coal and coke is used as a reducing agent, which results in large amounts of CO2 emissions. An alternative option is the application of a hydrogen-rich gas emitted in biomass utilization processes as a carbon-neutral reducing agent. Investigations in a retort process which were done at different temperatures and times showed excellent results concerning the achievable reduction rates and final contents of the heavy metals for various residues.IntroductionNowadays heavy metal containing residues like electric arc furnace dust (EAFD), dust from cupola furnaces, waelz slag, etc. are declared as hazardous wastes in a growing number of countries due to the leachability of the heavy metals in these residues. For that reason it is no longer possible to landfill these materials or use them for road construction or disposal works. Some land filling activities, carried out until now, have only been realizable because of some process modifications or cost intensive post-treatment steps of these residues. But the disposal capacities for such materials are decreasing, therefore increasing the prices. The second point for the growing disposal limitations is the stringent environmental legislations and regulations, which restrict the number and amounts of materials which can be dumped [1 – 5].From the other point of view these heavy metal containing residues usually have high contents of zinc, lead, iron, etc., which represent a significant value and therefore a big potential to recover these metals. This is why in recent years the number of recycling processes and the amount of recycled heavy metal containing residues have continuously increased. These recycling processes have the target to recover the valuable metals from the residual materials in the form of a saleable product as well as the stabilization of the slag produced in these processes [5, 6]."

Jan 1, 2011

Traditionally, surface coal mines in the Western United States have been limited by economics to depths between 150 to 200 feet. Utah International Inc., however, is now planning to strip coal its San Juan Mine in Northwestern New Mexico to depths ranging up to 400 feet while uncovering 20 feet of steam coal. This method is cost-competitive with nearby shallower coal deposits and underground mining of the same property. How trucks and shovels can pre-strip for a dragline, along with results of the planning process, comparison with alternate systems, capital requirements, operating costs and comparisons with other coal sources are all detailed. Also discussed are the major problems anticipated, how they might be corrected, and potential improvements to the concept. Introduction The San Juan Deep Stripping Project will be situated at Utah International&apos;s San Jean Mine. The mine is in the Four Corners region, so-called because four states enjoy a common border point about 30 miles to the northwest.(see Figure 1). The area is a semi-arid plateau region with an average elevation of 5,200 feet, receiving an average of 6 inches of precipitation annually

Jan 1, 1981

By Michel G. Grenier

Compliance with Diesel Particulate Matter (DPM) exposure regulation is currently performed using timeweighted average (TWA) sampling on underground mine workers. These samples are collected in the span of an entire shift and the resulting concentrations are compared to a legislated exposure limit. While this is very useful to determine the exposure level of an individual to DPM, it fails to clearly identify causes of exposure and highlight opportunities that could help reduce the exposure of workers in the course of the work shift. Real-time DPM monitoring measures the worker?s exposure as a function of time and helps identify circumstances where corrective actions can be taken or design changes can be made by the individual or the employer to reduce the overall exposure of the worker and peers. This work focused on obtaining DPM concentrations using a real-time polycyclic aromatic hydrocarbon (PAH) monitor. The aim was to demonstrate that this instrument, while not a direct DPM analyzer, was able to provide a concentration profile that could easily be linearly correlated to standard TWA elemental carbon measurements. In addition, several instances of improvements that could be implemented to reduce the exposure of underground employees were demonstrated.

May 1, 2010

By Subagyo

The condition of slag in a pyrometallurgical reactor is vital to ensuring control of the process. A new technique based on multivariate image analysis (MIA) of digital images has been developed to provide an online measurement of important slag characteristics, such as the presence of exposed metal, the presence of solid phases, and temperature. This paper shall describe the technique and provide some results from analysis using industrial plant data.

Jan 1, 2003

By E. Demir

Transportation cost is the dominant cost and accounts for almost half of the total mining cost in surface mining. Therefore, determining transportation cost is critically important for the economic feasibility of mining projects. Turkey produces around 85 million tons of lignite per annum. The biggest state-owned company, Turkish Coal Enterprises (TKI), accounts for 43 per cent of the country?s total lignite production. Around 85 per cent of the produced lignite is used in power plants for electricity generation and 15 per cent is used for domestic heating in cities and urban areas. On behalf of the Turkish government, TKI distributes around 2 Mt of lignite annually, at no cost to poor needy families countrywide in accordance with Social Assistance and Solidarity Funding aid. Subcontractors are utilized for lignite transportation, and conflicts arise due to the different transportation cost calculations at different mines. A robust model that provides unbiased cost estimations is therefore of paramount importance. This paper presents the transportation cost estimation software, NAKMAL, that has been developed for estimating the transportation cost of lignite from the mine face, including excavation and loading, to various final destination points through five different transportation scenarios. NAKMAL was designed using VisualStudio.NET, validated using field data and some case studies, and it is currently being used by TKI for calculation of transportation cost country-wide.

Jan 1, 2012

In this, the centennial year of The Institute, it is appropriate that the history of the Institute in New Zealand be recorded. I am indebted to John Dew, compiler of the centenary publication æMining People A Century - Highlights of the First Hundred Years of The AusIMM 1893 - 1993Æ, for many of the early historical references in this paper. In July 1892 the Amalgamated Mining Managers&apos; Association of Australasia held its annual conference in Ballarat, Victoria, Australia, when it was suggested by the delegate from Broken Hill that the time had arrived for the establishment of an Australasian Institute of Mining Engineers. Resulting from this meeting at Ballarat, a Provisional Committee was formed at Broken Hill with the object of forming The Australasian Institute of Mining Engineers having the following objectives. To promote the arts and sciences connected with the economic production of the useful minerals and metals, the welfare of those employed in those industries by means of meetings for social intercourse, and the reading and discussion of professional papers with the circulation by means of publications amongst its members and associates the information thus obtained.

Jan 1, 1993

By Carlton E. Brown

Impinger dust-counting methods are used by industrial hygienists for determining the number concentration of unhygienic siliceous dusts in industrial atmospheres. Various statements have been made regarding the size of the smallest particles revealed by the microscopic employed in such determinations. Published data on the subject are quite limited. This report presents information on the size of the smallest particles revealed by light-field and dark-field techniques applied to impinger and electric precipitator samples collected from experimentally established aerosols of silica dust and bituminous-coal dust. Size distribution and number concentration of particles of the various sizes in the aerosols were determined from samples collected by thermal precipitation simultaneously with the impinger and electric precipitator samples. The size of the smallest silica and bituminous-coal dust particles determined in the light-field counting method used was about 1./1, . There was relatively little variation in the values from 8 impinger and 33 A.-C. precipitator samples of silica dust and 13 impinger and 13 A.-C. precipitator samples of coal dust. The coefficients of variation of the values from the four sets of determinations were low, ranging from ± 7.7 to t 10 percent. This size of 1,14 is close to the limit of resolution of the microscopic method used and to various previously suggested values. The size of the particles determined in the dark-field counting method used was smaller than the size (about 0.28A ) of the smallest particles determined in the light-field, oil-immersion method used for the thermal precipitator samples.

Jan 1, 1951

By T. D. Mailula

Paper written on project work carried out in partial fulfilment of M.Sc.(Chemical Engineering) degree Chromite and talc are two major gangue minerals in platinum bearing UG2 ore processed from the Bushveld Complex in South Africa. During flotation, talc is effectively depressed by the addition of depressants. Chromite, on the other hand, is considered to be hydrophilic, its recovery is believed to follow water recovery and therefore recovered by entrainment only. In certain cases it has been shown that chromite can be activated by the reagent suite and hence is made amenable to true flotation. The aim of the work was to investigate the effect of the addition of copper sulphate as an activator and the effect of the depressant type and dosage on the recovery of chromite. The results of these experiments showed that copper sulphate, at higher dosages, activated the chromite. Low dosages of copper sulphate resulted in no chromite activation. This was observed at low depressant dosages of both IMP4 (guar gum) and KU5 (carboxymethyl cellulose (CMC)). When the depressant dosages were increased, at higher copper sulphate dosages, it was observed that the activated chromite was depressed by IMP4, but that the activation was still significant with the use of KU5. The activation of the chromite is attributed to the form of the copper species present in the solution and on the mineral surfaces at pH = 9 enhancing collector adsorption and thereby increasing hydrophobicity. These species were not measured directly and it is recommended that this should be further investigated using surface mineral techniques. Keywords: flotation; depressants; chromite; copper sulphate

Jan 1, 2003

By G. H. Lewis, C. L. Krcil, N. S. Harding, D. E. Havekotte

Introduction Limestone injection work was completed in a 440-kW (1.5-million Btu per hour) pilot-scale combustor in preparation for a 50,000-kg/h (110,000-lb per hour) industrial steam boiler limestone injection test program. The main objectives were to: (1) identify the important variables that affect sulfur capture, (2) determine the maximum SO2 removal, and (3) determine the effect of limestone addition on furnace operability and heat transfer. A more detailed report is given by Lewis et al. (1985). The test program was divided into two phases. The objectives of Phase I were to determine the important variables that affect SO2 reduction and to investigate the effect of limestone addition on combustor operation and heat transfer surfaces. The objective of Phase II was to determine, using only the important variables identified during Phase I, the conditions that resulted in the greatest sulfur dioxide reduction. Phase I Test program Using one limestone, five variables were identified as having an effect on SO2 reduction. These are noted with their respective ranges: heat release rate [103 to 166 kW/m3 (10,000 to 16,000 Btu per hour-cu ft)], Ca/S molar ratio (0 to 3), flue gas oxygen concentration (3% to 5%), additive particle size [90% -150 µm (-100 mesh) and 90% -45 µm (-325 mesh)], and burner stoichiometry (SR = 0.75 and >1.15). A 2.3% sulfur northern West Virginia coal, pulverized to a nominal grind of 70% -75 µm (-200 mesh), was burned for the tests. The limestone used was obtained from a Maysville, KY, quarry and contained 51.75% (wt) CaO. An 11-run statistically designed program (plus three duplicates) was used to screen the five variables. The effect of limestone injection on the combustor heat transfer surfaces was determined by comparing the heat transfer rates through a slag panel and fouling probes during periods with and without limestone injection. Combustor operation was determined by noting any operating problems that occurred during the tests. Test procedure After furnace wall temperatures had stabilized at operating conditions, heat transfer surfaces (slag panel and fouling probes) and the convection section were blown clean, and a four-hour test was begun. The

Jan 12, 1986

By J. F. Barkley

At the request of several Federal agencies, tests were conducted on a relatively recent type of anthracite -burning equipment named the Anthratube. This device, rated at 130,000 B.t .u. per hour, was designed to burn Pea-size anthracite automatically for steam or hot-water house heating and for domes-tic hot -water supply. ACKNOWLEDGMENTS The helpful cooperation of the Anthracite Institute and the manufacturers of the equipment, Axeman-Anderson Co., Williamsport, Pa., is gratefully acknowledged.

Jan 1, 1953