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By A. Dolatmoradi

Nanocrystalline structure formations produced by severe plastic deformation in Fe-0.15C with initial ferritic-pearlitic and IF steel with ferritic microstructures have been studied through microstructural observation and microhardness measurements. It was found that the nanocrystalline region first forms near the surface of samples due to localized severe deformation. It was also observed that the nanocrystallization rate of Fe-0.15C and IF steels and the deformed layer thickness in these two materials are different with similar milling conditions. The crystallite size and structural evolution of the samples during milling was studied by employing XRD and SEM.

Jan 1, 2010

By N. Hiroyoshi, R. D. Corpuz, M. Ito, Hokkaido University, C. B. Tabelin, S. Veerawattananun

"Acid mine drainage (AMD), the very acidic and heavy metal-contaminated leachate generated when pyrite-bearing rocks are exposed to surface oxidizing conditions, is a serious environmental problem encountered after the closure of mines and mineral processing operations. In this study, we investigated the effects of soluble phases and metallic oxides, which are commonly found in strongly weathered pyritic wastes, on pyrite oxidation. Strongly weathered pyrite containing melanterite (FeSO4·7H2O) as the main soluble phase was obtained from Furikusa mine, Japan. The sample was washed using two methods to vary the relative amounts of melanterite in the sample. The effect of metallic oxides on pyrite oxidation was evaluated using ultrapure hematite suspensions. Our results showed that under acidic conditions, the effect of soluble salts on the oxidation of pyrite was stronger than hematite. More thorough washing of the sample resulted in the formation of an arsenic-bearing iron-oxyhydroxysulfate coating that minimized pyrite dissolution. This oxidized layer became relatively thicker and mechanically stronger when hematite was introduced after the more thorough removal of soluble salts. Characterization of this “coating” coupled with geochemical modeling suggest that it is most probably composed of two materials: schwertmannite and scorodite. Based on these results, a new approach to suppress pyrite oxidation by directly using iron-oxyhydroxysulfate as coating material is introduced.INTRODUCTION Acid mine drainage (AMD), the very acidic and heavy metals-contaminated leachate produced in closed/abandoned mine sites (Evangelou, 1995), mineral processing and coal cleaning tailings (Evangelou, 1995), and tunnel construction waste rocks (Tabelin and Igarashi, 2009, Tabelin et al., 2012), is one of the oldest and probably the most serious environmental problem of anthropogenic origin. When released to the environment, it rapidly pollutes river, soil and groundwater systems leading to the destruction of affected ecosystems. AMD is produced when pyrite (FeS2), one of the primary gangue minerals in sulfide ores and coals, is exposed to oxidizing conditions as illustrated by the following reactions:"

Jan 1, 2016

By M. Reza Bateni, M. Zandrahimi, J. A. Szpunar

Titanium aluminides and nickel aluminides offer the potentials, as coating materials, for high temperature and aerospace applications. In this research, attempt has been made to develop Al-Ti and Ni-Al intermetallic compound coatings on the surface of Inconel 738. The coatings applied through pack cementation and simultaneous diffusion annealing processes. Scanning-electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDAX) and grazing angle X-ray diffraction were used for evaluating of coating structure. It was demonstrated that the pack cementation technique could be used to develop TiAl3 and AlNi intermetallic compounds coating on Inconel 738 substrate. When pack cementation technique is based on a halide-activated pack with aluminum and titanium powders, the coating consists of TiAl3 intermetallic compound phase. Whereas, by pack aluminization of Inconel 738, the coating consists of AlNi intermetallic compound phase.

Jan 1, 2004

By BRIAN HITCHON

Calcium, magnesium, bromide and iodide extraction from formation waters for use as industrial minerals has occurred in several countries, but not yet in Canada. Potential commercial brine fields exist in th e Upper Devonian Beaverhill Lake Formation of so uthern Alberta, and the Middle Devonian Elk Point Subgroup of north-central Alberta, f rom which calcium, magnesium and bromide are potential products. Iodide contents in fo rmation waters f rom the Upper Cretaceous Belly River Formation and the Lower Cretaceous Viking and Bow Island fo rmations in central and southern Alberta are at the lower range limit of commercial iodide-bearing formation waters elsewhere in the world. Available information is insufficient 10 outline potentially commercial areas in Alberta, but such info rmation can be most easily obtained f rom test borings for shallow natural gas. Lithium is not now produced commercially f rom formation waters but its content should be monitored in view of f uture increased demand for this metal.

Jan 1, 1984

By I. H. Warren

"An analysis of form-coking processes is presented in terms-of their fundamental mode of operation and their relationship to other coking processes. Their possible future role in cokemaking is assessed. IntroductionAny consideration of prospects and possibilities for form coking must commence with the iron and steel industries-their likely future growth pattern on a world and regional basis and the potential direction of future developments in iron and steelmaking technology.From the numerous estimates which have been made of the future consumption of steel, it would appear that a growth rate of 3lllo between now and the year 2000 is likely. Radical changes in steel making technology are unlikely to be commercially adopted on any significant scale during the next twenty years . However, widespread commercialization inter alia of continuous casting and direct reduction, growth of electric furnace steelmaking and a decrease in coke rates will all contribute to a growth rate for metallurgical coke that certainly will be less than that of steel."

Jan 1, 1980

"This paper presents results of ongoing research being carried out at the University of New South Wales into improved methods for estimating rock mass strength. In this paper the rock mass strength of Hawkesbury Sandstone is assessed. An estimate is first made based on an extensive database of intact rock strength data being collated by the author and the assumption that the rock mass strength can be determined following the GSI approach. The resulting strength envelope is then compared with nine documented case studies where stress induced failure has occurred in tunnels excavated within Hawkesbury Sandstone. The case studies cover a range of conditions:• construction dates from 1880s to 2006• spans from 3.2 to 12.5 m• depths from 17 to 124 m• excavation methods of drill & blast, roadheader and TBM.Finite element modelling is used to assess the likely magnitudes of the stresses present at the time of failure. The finite element models are interrogated to provide the values of major and minor principal stresses in and around the mapped failure zone. Failure and stable points are then compared to the rock mass strength envelope(s) of Hawkesbury Sandstone derived using the Hoek-Brown criterion and spalling criteria. The Hoek-Brown rock mass strength envelope differentiates between the ‘failed’ and ‘stable’ zones remarkably well.INTRODUCTIONStress induced failures of rock masses are fortunately rare in civil tunnelling. However, when they occur they provide an opportunity to calibrate an assumed rock mass strength criterion. This paper compares an estimate of rock mass strength for the Hawkesbury Sandstone with the following cases where stress induced failure occurred in tunnels excavated within Hawkesbury Sandstone.• Cataract & Devines Tunnels of the Upper Canal (Upper Nepean Scheme)• Malabar Outfall Tunnel• Sydney liquefied petroleum gas (LPG) Storage Cavern• Northside Storage Tunnel• Cross City Tunnel• Lane Cove TunnelTwo-dimensional finite element modelling is used to assess the likely magnitudes of the stresses present at the time of the failures. The principal stresses are then compared to the assessed rock mass strength envelope(s) of Hawkesbury Sandstone derived using the 2002 Hoek-Brown criterion (Hoek et al., 2002) and the spalling criterion suggested by Diederichs (2007)."

Jan 1, 2015

By Norman O. Lotter, Dominic Fragomeni, Jorge Oliveira, Dee J. Bradshaw, Rebecca Monnapula

"The role of mixed collectors in enhancing the metallurgical performance of sulphide flotation processes was reviewed in 2008, and later published as an integrated theory by Lotter and Bradshaw, 2009. The theory proposed that xanthates, dithiophosphates and dithiocarbamates could be synergistically combined in an optimal formula to deliver improved grade and recovery. The approach uses a five-step structure, viz.1. A mineralogical study of the ore to be treated, identifying and quantifying the economic minerals (with hosting and association) and gangue species present.2. Selection of candidate collectors from this mineralogical information and from the known pulp conditions of that operation (e.g. Eh, pH).3. Design and execution of a factorial experiment to estimate and test the main effects and interactions, and to model the response surface for an optimum formulation [Box et al., 1978].4. Use of a High-Confidence Flotation Test platform in the factorial to reduce overall errors and allow for clearer observations [Lotter, 1995; Lotter and Fragomeni, 2010].5. Statistical design of a plant scale trial to measure and validate the gains [Napier-Munn, 1995; Lotter et al., 2009]. Eland Platinum, which was commissioned in November 2007, appointed a team to apply this theory to formulate an optimized mixed collector suite for use in the operation. The West Pit ore (UG2 - Normal ore) was sampled at site and brought to Xstrata Process Support, Sudbury, Canada, for mineralogical and metallurgical testing in 2008. Microprobe and QEMSCAN measurement characterized the type, grain size and textural association of the discrete Platinum Group Minerals (PGM) present. From the mineralogical data, it was clear that a mixture of dithiocarbamate and two xanthates would be a likely reagent suite selection. A factorially designed set of High-Confidence Flotation Tests studying these was performed, concluding that an optimal suite using certain amounts of these collectors was a viable formulation that would advance the grade and recovery performance at Eland above the standard PIBX by approximately 2.13% 4E PGE. The plant trial, which used a form of the replicated block design after Napier-Munn, 1995, and Lotter et al., 2009, exceeded this estimate with an overall PGE recovery gain of 2.48% (absolute basis) and a concentrate grade gain of 26.4 g/t PGE (absolute basis), as well as reducing chrome in concentrate from 2.04 to 1.62% (absolute basis). These gains proved to be statistically significant using the analysis of variance method, and have validated the theory."

Jan 1, 2011

By M. K. Kim

This study presents a framework for quality inspection of precast concrete components using the 3D laser scanning technique. As precast concrete-based rapid bridge construction is getting standardized, quality assessment of the precast concrete becomes critical for preventing any failures during the construction process. Moreover, as Building Information Modeling (BIM) gains popularity in the construction industry, autonomous and intelligent inspection systems are needed. Current method for quality control of precast concrete components, however, heavily relies on visual inspection and contacttype measurements, which are time and labor demanding. Also, storage and delivery systems of inspection information such as the procedures and results of quality inspection are lacking. To overcome these limitations of the current quality assessment technique for precast concrete, this study aims to develop a BIM-based framework for efficient quality inspection of precast concrete with the use of a 3D laser scanner. First, we formulate practical guidelines including detailed inspection procedure, selection of optimized scanner and scan location, inspection criteria, and data storage and delivery system. Second, to investigate the applicability of 3D laser scanning to precast concrete quality inspection based on the proposed framework, a case study inspecting quality of a lab-scale object assumed as precast concrete component is presented for detecting defects.

Aug 1, 2013

By J. M. Hemstock, H. L. Ames

THESE forums have been held annually since they were introduced by Mr. L. E. Djingheuzian in 1957. The response of millmen to questionnaires such as the one this year is ample evidence of the interest these create. This year's topic is unlike those of past years since it is an attempt to understand a new concept of grinding rather than to improve the old. Before, we were thinking in terms of 2-5 cents improvement in grinding costs, now we will be discussing savings of 15-2 5 cents. As a background for this forum we will begin by summarizing the major controversial issues relating to grinding with steel, many of which will undoubtedly apply to pebble milling. Our •task to-day is to learn what has already been done in pebble milling and obtain a fair overall view of this method of grinding.

Jan 1, 1961

By W. H. Zieman

"THIS IS THE THIRD of the consecutive Annual Forums on Grinding that were instituted by Mr. L. E. Djingheuzian in 1957. The first was on the subject of Ball Milling (Transactions, Volume LX, 1957) and the second on The N on-Cataracting Ball Mill (Trans-actions, Volume LXI, 1958). From the discussions at these forums it was evident that one of the most important factors affecting the efficiency of grinding is the shape of the liners. In order to make a study of liners in use, it was •decided to seek the co-operation of operators across the country by sending out questionnaires requesting basic information. Additionally, these operators were urged to set down briefly any pertinent information on the subject acquired through experience and experiments at their own particular plants. A compilation and analysis of these data were to form a basis for discussion at the Forum on Liners at the Annual Meeting in Montreal, April, 1959. The response of the milling fraternity to this solicitation was most gratifying, and clearly indicated the importance attached by the operators to the effect of liner design upon overall grinding performance."

Jan 1, 1959

MR. J. F. MYERS, Consulting J3eneficiation Engineer, Greenwich, Conn.: In the written discussion contributed by Mr. F. C. Bond in item ( 2) (page 515), speaiking about the significance of the ratio of mill diameter to the make-up ball diameter, he states: "When this ratio exceeds 100 the power and capacity of the mill are de-creased"; and the paragraph ends with a reference to the 30 per cent ball volume "with some de-crease in mill capacity". I believe this broad statement is incorrect. When we are dealing with a non-cataracting mill, pre-ceded by a good rod mill, there is a slight increase in capacity, but the power does drop. The second point that I consider needs consideration is Mr. Bond's item (8), Proper Mill Speed (page 516). This paragraph should be qualified to cover single-stage mills only. It does not apply where a rod mill is followed by a non-cataracting ball mill. The statement as is, with no qualification, gives an erroneous idea of proper mill speeds.

Jan 1, 1957

By W. H. Zieman

NORMAN WEISS, Milling Engineer, American Smelting• and Refining Company: The subject of the Forum on Rod and Ball Mill Liners is very fascinating, and there is no end of discussion when operators get together on grinding. However, the hypotheses and suppositions easily outrun the facts, especially when we •consider the inaccuracy of many reported observations. Still surprisingly small is the number of concentrators even reasonably well equipped to measure power consumption of each grinding mill, together with running time, so that data on this tangible factor, at least, can be obtained with precision. While the more elaborate devices of this nature, producing for each 24-hour period the total power consumption, average kilowatt hours per hour, short-term demand chart, instantaneous demand, and print-out, may cost in the neighbourhood of $2,500 per mill and may be difficult to justify, the combination of an ammeter, watthour meter, and running-time meter will cost only a few hundred dollars, so there appears to be little reason not to in-stall them in view of their numerous advantages.

Jan 1, 1959

By L. E. Djingheuzian

ANON-CATARACTING (N-C) ball mill is so operated that the balls are not thrown in-ward at the top of their paths. The result is to maintain, in the mill, a quiescent pool in which classification will occur at a limiting size corresponding to the pulp density. N-C operation is produced by effecting proper relationship among mill speed, ball diameter, volume of ball load, and pulp density. Such operation is typified by the primary ball-mill operation of the Tennessee Copper Company, Copper-hill, Tenn., and the Cleveland Cliff Iron Company, near Ishpeming, Mich.

Jan 1, 1958

By W. Beres, Li. J.

The finite element method (FEM) has been applied to investigate the stress fields and deformation of a TiN/Ti-6A1-4V coating/substrate system subjected to nanoindentation. MSC Patran and MSC Marc were used to prepare the three-dimensional finite element models and to perform the simulations of the Vickers nanoindentation experiments. Pure silicon and TiN/Ti-6A1-4V coating/substrate system were analyzed. The properties of the materials were assumed to be homogeneous and isotropic with a linear hardening behavior. The reverse method was used to extract material properties, such as the yield stress and strain hardening coefficient, from the numerical results by comparing the simulated indentation load vs. penetration depth (P-h) curves with those obtained experimentally. Both non-linear elastic and non-linear elastic-plastic analyses were carried out for the coating/substrate system. The results are given for four different coating thicknesses.

Jan 1, 2004

By V. G. Papangelakis, T. Clark, G. Kolliopoulos

Sustainability of the hydrometallurgical industry requires the development of processes for effective water recovery; if process water is recovered and recycled, fresh water intakes will be reduced. Forward osmosis (FO) is an innovative membrane process that promises to recover water from industrial process aqueous streams or seawater with less energy input compared to reverse osmosis (RO) and evaporation; the energy efficiency relies on the spontaneity of the process (no energy input required). The driving force of the process is the osmotic pressure gradient between a dilute feed solution (process water) and a concentrated draw solution. The draw solution is an engineered aqueous solution that contains a highly soluble chemical reagent that is able to osmotically "draw" only water from the dilute stream, through a semi-permeable membrane, leaving behind a small volume of concentrated brine. The draw solute is separated and recovered for reuse, leaving behind water. The main energy requirements of the FO process arise from the separation and the regeneration of the solute chemicals from the diluted draw solution. This work focuses on the evaluation of aqueous carbonated trimethylamine (TMAH:HCO3) as the draw solution and reports recent findings on the separation efficiency of TMA and CO2 from the solution.

Jan 1, 2015

By K. Law

"The Hatch Product Transport (HPT) system is a highly flexible and configurable route selection and sequencing system for controlling large bulk material handling facilities. The system has a generic control algorithm that can be configured to suit any material handling facility. It can also be easily reconfigured to cater to plant expansion or modifications without incurring significant disruption to the existing production, costs in testing, and re-commissioning, thus achieving cost savings throughout a facility’s lifecycle.This new material handling control system has been installed at BHP Billiton’s Port Hedland iron ore terminal to facilitate its expansion to beyond 100 Mt output capacity."

Jan 1, 2006

By J. M. Cummings

The importance of controlled sand properties to the production of quality castings has been recognized by foundry men for many years, but the maintenance of requisite standards results in a relatively high sand consumption, which in steel foundries, for instance, may range from half a ton to over one ton of sand per ton of finished casting. During the war, obtaining and maintaining adequate sand supplies became a serious problem in many foundries, owing to increased wartime production and serious 'bottlenecks' in transportation. As a result, considerable interest was aroused in the possibilities of various sand reclamation systems by which up to 85 or 90 percent of discarded sand may be returned to a usable condition. During the past five years or so, a number of sand recovery installations have been made by both ferrous and non-ferrous foundries in Canada and the United States, and have resulted in substantial reductions in sand costs in every case. The possible benefits of sand reclamation are particularly apparent in British Columbia where no suitable sands for steel and heavy iron foundries occur naturally, and where freight costs on imported sands are considerably higher than initial selling prices. This is well illustrated by the fact that silica sand, which sells for about $2.00 per ton at pits in Illinois, is laid clown in British Columbia for around $11.00 or $12.00 per ton. The operating costs quoted for certain of the reclamation schemes, i.e. $0.25 to $1.50 per ton, may actually be no higher than the cost of waste sand disposal in city-located foundries. In view of the foregoing considerations, the British Columbia Research Council has undertaken a study of the possibilities for sand reclamation, with particular attention directed to its application in local steel foundries. No commercial occurrences of silica sand are known in the Province, and, with this in view, the Council previously investigated the possibility of recovering silica sand from local impure sands. Results were definitely encouraging, but it was felt that the present market is too small to permit economical production by the method developed.

Jan 1, 1947

By T. R. Stanley

Introduction The purpose of this paper is to interest mining men in the economic possibilities of sand deposits suitable for modern foundry work. Many members of the profession are constantly travelling over the country and it is felt that some knowledge of the necessary properties of foundry sands will enable these men t0 recognize such deposits. It is the experience of the writer that good sands suitable for the varied work of a foundry, such as that of the Consolidated Mining and Smelting Company, at Trail, are almost impossible to obtain from western Canadian sources. It is hoped that the following discussion may arouse some interest in the search for such sands. Sands are used in foundries for two purposes. The main use is for making moulds suitable for receiving hot metal. The mould must retain the? required shape until the metal has solidified. The second use of sand in the foundry is as an abrasive in sand blasting. This is a relatively minor use, and consequently will not be dealt with in detail. Any coarse sand with a high content of quartz will serve this purpose, but round-grained sands are superior to angular types, because they have not the same tendency to shatter on impact with the casting. Sand plays an extremely important part in the successful production of sound castings. This is more evident today than ever before, due to the greater variety of castings and alloys, each of which requires special sand characteristics. Poor sand is responsible for a great many foundry troubles which formerly were attributed to bad? metal; in fact, one investigator goes so far as to say that ninety per cent of bad castings can be traced directly to the sand. Very little of the vast amount of sand distributed over the earth's surface is suitable for moulding. It is the purpose of this paper to describe briefly the properties which are essential in good moulding sand. Sand for this work must be able to withstand the wash and hydrostatic pressure of molten metal, and yet be sufficiently porous to allow the gases generated in the mould to escape.

Jan 1, 1935

By Eiichi Sato, Koichi Kitazono, Hiroshi Masuda, Kenta Higane

"The present study investigated the low-temperature creep mechanisms in ultrafine-grained (UFG) aluminum manufactured by accumulative roll bonding. UFG aluminum with grain size 0.39 µm showed steady state creep even at room temperature under low stresses as confirmed by the creep curves in the strain rate–strain plot. The low-temperature behavior was divided into four regions by three distinctive stresses, sI, sII and sIII: sI (=45 MPa) is denoted as the micro-yielding stress with which dislocations start movement, sII (=85 MPa) the dislocation-multiplication stress above which dislocations multiply with creep deformation, and sIII (=171 MPa) the conventional yield stress above which macroscopic plastic strain is generated. During low-temperature creep, below sI, negligible plastic strain is generated. Between sI and sII, creep deformation with stress exponent 2.5 occurred, which is accommodated by dislocation absorption into grain boundary and grain boundary sliding, similarly to the low-temperature creep of HCP metals. Between sII and sIII, creep deformation with stress exponent 7.0 occurred, whose mechanism is similar to the low-temperature creep of coarse-grained aluminum. Above sIII, power-law breakdown occurred.INTRODUCTIONIt is well understood that the creep deformation brings about at high homologous temperatures (T/Tm) of >0.4, where Tmis the melting point, with diffusion processes. Recently, the importance of aluminum is increasing for cryogenic temperature parts such as a metallic liner or a cap in high pressure-hydrogen vessels, and the presence of creep behavior in aluminum at room temperature has become recognized (Matsunaga, 2013;Kassner, 2015).In HCP metals and alloys, especially intitanium, steady-state creep behavior appears at room temperature with apparent activation energy of1/10 of that for self-diffusion(Neeraj, 2000; Matsunaga, 2009).On the other hand, Kassner (2015) claims that aluminum shows creep behavior at room temperature with apparent activation energy of 4/5of that forself-diffusion, but never reaches the steady state. We should note that it is derived from the data obtained from short-term creep tests of few hour, and Matsunaga (2013) already claimed the presence of steady state in room temperature creep in aluminum with activation energy of 1/5of that for self-diffusion.The mechanisms for low temperature creep are considered different between HCP and FCC metals: in HCP metals, grain boundary sliding is observed and is thought to accommodate piled-up dislocations at grain boundaries through absorbing them. The so-called slip-induced grain boundary sliding occurs with low number of activated slip systems(Matsunaga,2009).On the other hand, in FCC metals, many activated slip systems bring about work hardening with dislocation cell structure formation. In the initial stage of creep, it results in primary creep (Kassner, 2015), but Matsunaga (2013) claimed that once the annihilating of a cross-slipped dislocation to another reaches balance, steady state is established. It has been, however, strongly required to show more convincing experimental verification for the presence of steady state in FCC metals at low temperature."

Jan 1, 2018

By Xiaozhu Chen, Qi Ping, Pu Yuan, Qinyong Ma

"In order to investigate the fractal feature of coalmine deep rock fragments under impact loads, variable cross-section split Hopkinson pressure bar apparatus, 50 mm in diameter, was adopted to conduct impact compressive test for rock specimens from -962m deep coalmine. Various impact pressures, such as 0.3, 0.6, 0.9 and 1.2MPa, were selected to implement different loading rates. Sieving statistical analyses were conducted for rock fragments after being impacted, and the particle size distribution of broken rock in various loading rates were calculated with the fractal method and then the corresponding fractal dimension was obtained. Test results shows that there is a good self-similarity and fractal feature in fragments distribution of deep coalmine sandstone under impact loads. The fractal dimension of fragments is between 1.9 and 2.7. The research also indicates that there is an approximate power relationship between dynamic compressive strength and fractal dimension, and a strength power relationship between fractal dimension and average strain rate. Moreover, there is a linear relationship between fractal dimension and specimen absorbed energy. The rock fractured process can be quantitatively described through fractal dimension, which can reflect the deep rock broken degree and is an ideal index to evaluate the distribution of rock fragments.INTRODUCTIONBroken rock is one of the most basic processes in mining operations, rock fragmentation has always been an important index to evaluate rock breaking effect (Xu & Yu, 1984). Macroscopic fragmentation of rock material is the final results of continuous development, expansion, gathering and cutthrough of internal micro-cracks. This process, developing from microscopic damage to macroscopic fragmentation, is an energy dissipation process and shows fractal characteristics (Xie, 1993). Turcotte (1986) has conducted statistical analyses of fragmentation for different kinds of geological materials under various broken conditions, and arrived at the conclusion that fragmentation distribution is a fractal."

Jan 1, 2015