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By Rod Maclean, George Stewart

"This paper covers the planning, development, and mining of an underground pillar complex using a bulk mining method. To achieve the long-term goal of continually improving our operating processes, all cut-and-fill and undercut-and-fill workplaces at Thompson Mine have been evaluated for their conversion potential to the bulk method referred to as VerticalBlock Mining (V.B.M.).Since December 1979, conversion has occurred to the extent where 80% of the ore hoisted is mined using Vertical Block Mining (V.B.M.).Productivity and profitability have been substantially improved by converting to this bulk method, especially in pillar areas.IntroductionThompson Mine is a 6000 ton per day underground nickel mine located 3 miles outside the City of Thompson, 400 air miles north of Winnipeg . The mine has two shafts, T-l and T-3 (Fig. 1). The T-l shaft is 4427 feet deep with the deepest mining taking place on 4000 level. The T-3 shaft, which is the area of this presentation, extends to a depth of 2607 ft with the deepest operating level at 2400 ft. The two shafts, some 10 000 ft apart, are connected underground on numerous levels. The ore mined at T-3 is trammed on 2400 level to the T-I main ore pass and hoisted through the T-l shaft. Eight hundred and fifty thousand cubic feet of fresh air per minute ventilates the mine.The 1400 level 310 pillar complex is located in the T-3 mine area. There are six rib pillars, two crown pillars and one main pillar (boundary pillar between cut-and-fill stopes) within the complex (Fig. 2). The majority of the ore in this area has been mined using mechanized cut-and-fill techniques .Undercut-and-fill mining was the method originally planned to recover these pillars. It is slow, labour-intensive, and requires extensive use of timber during the mining cycle. The extraction drifts in the area are heavily timbered due to their proximity to the ore and the age of the facilities. Increasing drift maintenance costs and the successful mining of two main pillars with V.8.M. techniques provided the stimulus to review the mining plans for this area."

Jan 1, 1988

By P. G. Keohane, J. S. Drake

"Cominco's Polaris Mine is a lead-zinc underground operation that began commercial production in early 1982. The mine site is located on Little Cornwallis Island in the Canadian Arctic at a latitude of 75°23'N and at a longitude of 96°55'W. The nearest settlement, Resolute Bay, some 100 kilometres southeasterly from the mine, is accessed from the mine by light aircraft. The mine site can be accessed by sea during the six-week ice-free period each year. During this time all major operating supplies are brought to the mine and the lead and zinc concentrate products are shipped out to market.GeologyThe Polaris orebody lies near the top of the Thumb Mountain Formation of Ordovician age. This formation is a relatively homogeneous section of thin to medium bedded limestones which are brecciated and dolomitized in the area around the orebody. The deposit is described as a Mississippi Valley-type orebody. Ore minerals are sphalerite and galena with the waste being predominantly dolomite with calcite and marcasite. The ore is quite porous with voids being generally filled with ice as the mineralized zone lies entirely within permafrost. Reserves consist of about twenty million tonnes of ore grading 3.8% Pb and 14.3% Zn with a further three million tonnes of inferred ore at a slightly lower grade.The orebody strikes in a north-south direction with the hangingwall dipping at about twenty degrees to the east. It is generally conformable with the stratigraphy. The footwall in the western portion of the orebody, the Panhandle, lies about 10 to 30 metres below the hangingwall. To the east the footwall drops sharply, creating an orebody height of up to 110 metres in what is referred to as the Keel Zone. The Panhandle Zone has typically 80 - 110 metres of cover above the hangingwall , About 25% of the reserves are in the Panhandle Zone, the remainder being in the Keel Zone. Figure I illustrates a plan view of the orebody relative to other surface facilities on the property and Figure 2 illustrates a simplified section through the Panhandle and Keel Zones."

Jan 1, 1985

By Jaime V. Ongpin

"The author will give a capsule history of Benguet Corporation and attempt to identify its operating environment and underlying ""strategy"" until 1974, when the company's management assumed office. The company's operating environment and ""interim strategy"" from 1975 to 1980 will be described. The discussion will cover an environmental forecast and define the company's"" strategy for survival"" for the balance of this century.IntroductionIn December last year, I was asked to deliver a pa per for the management lecture series a t the Asian Institute of Management in Manila. The paper was entitled "" The 1970's: A Decade of Disaster For New Mining Projects"" . In that paper, it was my task to review the results of new mining projects in the Philippines during the previous decade. The task was not a happy one, for the results themselves were not only unhappy, but disastrous on a scale unprecedented in Philippine history. Out of a total of 17 major mining project s involving an aggregate capital investment in excess o f US $2 billion during the 1970s, only three project s have been profitable, and all the rest have either gone "" belly up"" or are teetering on the very edge of financial disaster.It is in the context of this shocking record of widespread financial dislocation in the Philippine mining industry, (which in varying degrees appears to have been paralleled in virtually every other country in the world where mining is an important sector of the economy) that I address myself tonight to the theme of this symposium. My paper is entitled ""Risk Management Strategy in Mining"" and it is sub titled ""Can Benguet Corporation Survive to Celebrate its Centennial in 2003?"". I have inserted the word ""Strategy"" and added the subtitle, because I wish to make it clear first, that my presentation to you tonight will be focused exclusively on the strategic aspect s of risk management, and second that I will limit myself to Benguet's own ""in-house"" experience and perspectives on this subject. I would caution you therefore, to consider my views within this restricted framework, and in light of the particular and sometimes peculiar circumstances within which Benguet Corporation operates."

Jan 1, 1983

By Charles A. Schacht

"Relining, lining maintenance, and ladle repair can represent a significant cost in steelmaking. Therefore, the objective of all steelmaking shops is to minimize this cost and to maximize the lining life. However, the thermomechanical behaviour of the ladle lining is highly complicated and sometimes misunderstood. The ladle design also has a significant influence on lining life. Other factors which have a direct influence on lining life are the shop lining installation practices and manner in which the ladle is used. The objective of this paper is to provide an understanding of the impact of these factors as related to improving the integrity of the lining and increasing lining life.Fundamentals of Steelmaking Ladle Lining Expansion ForcesNumerous studies have been conducted by the author on steelmaking ladles with molten metal capacities ranging from 110 ton s to 350 tons. The steelmaking ladle typically has a sidewall plate with a slight taper and for analytical purposes can be classified as a cylindrical vessel.A typical ladle is described in Figure I. The ladle sidewall lining usually consists of a working lining and a safety lining. Although the type of refractory used in the working lining varies based on the type of steel produced and other metallurgical requirements, the refractories typically used are: 70% alumina brick; direct bond mag-chrome brick; resin bond dolomite brick; and direct bond dolomite brick. Fireclay brick, high alumina brick, or a similar strength brick is used as the safety lining.Normally, the ladle lining is exposed to a through-thickness temperature gradient and restrained by the ladle sidewall plate, is described in Figure 2. The hot face side of the refractory lining develops a compressive thermal force and the ladle sidewall plate develops an equilibrating tensile force. The radial joints open on the cold side of the working lining as the lining joints have little or no tensile strength. A radial compressive load (P) develops between the working lining and the vessel shell due to the thermal restraint imposed on the lining by the shell. The radial compressive load is transferred from the working lining through the safety lining onto the ladle sidewall. Therefore, the safety lining must have the strength to accommodate the radial compressive load (P)."

Jan 1, 1991

By F. Parada Luna, F. Parada Torres, J. Salvo, A. Reghezza

In the pyrometallurgical processes of copper concentrates, arsenic is preferentially concentrated in the dusts carried by the gases as a result of their volatility and subsequent condensation in the gas cleaning train. In this work results obtained by alkaline leaching of the dusts from Ministro Hales roasting plant, belonging to Codelco, are presented. For the Ministro Hales plant the alkaline leaching would be an alternative to the recirculation of dusts to the roasting furnace. The experimental study considered NaOH and NaOH plus NaHS leaching of two samples of dusts, with 4.24 and 2.55% arsenic respectively. The results show that it is feasible to extract 90% of the arsenic and 50% of the antimony at room temperature using only NaOH, and when the temperature increases to 95ºC, the extractions of As and Sb increase. Copper remains in the solid residue with less than 1% dissolution, and the NaOH net consumption was approximately 140 kg/t of dust. In leaching tests with NaOH + NaHS, two types of methods were tested, baking plus leaching with water and direct leaching with a NaOH+NaHS solution. With the second method arsenic extraction increased to 95% and copper dissolution was less than 0.01% at 85ºC, NaOH 100 g/L, NaHS 90 g/L, 1.5 h and L/S ratio of 5/1 (L/kg). The bismuth remains stable in the solid in all cases. INTRODUCTION The presence of arsenic in copper concentrates has increased with time and the environmental regulations are becoming increasingly more stringent. In concentrate treatment pyrometallurgical plants, most of the arsenic is volatilized condensing in the gas train and is collected along with the entrained solids to form the flue dusts. Under these conditions, in smelters of copper concentrates with high arsenic content, the dusts are being treated in hydrometallurgical plants to extract and stabilize the arsenic, which also means that most of the copper contained in the dust is co-extracted with the arsenic. This affects the recovery of copper in the smelter and an alternative such as the selective alkaline leaching of arsenic, would allow the copper from flue dust to be recovered.

Jan 1, 2019

By J. N. Cram

"The comments given are to help allay generally accepted ideas that the handling of arsenic as arsenic-trioxide (As2o3J in and from off gas pyrometallurgical operation fumes is difficult, hazardous and expensive. It need not be any of these things if the basic and rather unique chemic3l and physical properties are understood and taken care and advantage of through present day technologies. These particular characteristics are:-(1) As2o3 sublimes and re-condenses, at a relatively low temperature;(2) As2o3 is, for practical in-plant purposes, insoluble in water at ambient temperatures and quite soluble in water just below the boiling point;(3) residual suspended and dissolved As 2o3 can be removed from water by complete dissolution with very little sulfuric acid, followed by the addition of small amounts of ferrous sulfate and calcium chlorate, with oxidation to the ferric and arsenite state and precipitation of an insoluble ferric calcium arsenate, thereby lowering the As2o3 content of solutions to acceptable levels. Even lower levels of non-toxic forms of arsenic solids and residual As2o3 in the water solutions can be attained by also using phosphate, and lime, along with the above.A background re past arsenic processing methods, present day operations, plus predictions re future trends, and hazards, are outlined."

Jan 1, 1979

By K. N. Bolatbaev, S. S. Naboichenko

The initial rates of dissolution of pyrite, chalcosine, sphalerite and galena in acidic sulphate solutions under oxygen pressure were measured in the range of Poe = 0.2-1 MPa, 130-180 °C, [H2SO4]0 = 0.2-0.7 M, and in the presence of surface-active agents and agitation producing Re = 4-16 x 103. Reaction orders, activation energies, and values of reaction constants for these oxidation reactions were established. The reactions also were shown to be diffusion-controlled; and the rates demonstrate a linear dependence on the surface area of the sulphides. A surface reaction model, in which oxygen is transported through a solid layer of surface products, has been advanced. The initial stage of high-temperature interaction at pH <7 is suggested to involve a chemical activation of the sulphide surface and is described by the following general reaction: MenSm + H3O+ Men-1 Sm-1 (HS-)s + H2O The subsequent oxidation of surface complex HS- to S0 or SO2-4 occurs with the assistance of Fe(III), Cu(II) ions depending on temperature and the redox potential of the medium, which are defined by oxygen pressure and composition of the reaction mixture, especially concentrations of H2SO4 and metals with variable valence. General process kinetics are complicated due to the formation of by-products on the basis of Fe3+ Pb2+, Cup ions, which displace the kinetics into the diffusion region.

Jan 1, 2004

By Antonio Laguna

During the past few years, synthetic efforts have been addressed to the synthesis of polymeric materials with optical or semiconducting properties or even with capabilities to act as sensors for volatile organic compounds (1). The most recent studies have been concerned with the synthesis of heterometallic systems with short metal-metal interactions and the determination of their optical properties. These complexes are undoubtly interesting from a theoretical viewpoint and include an emerging class of luminescent materials, in which the observed luminescence results mainly from the interactions among the different metal centers, as well as the environments of these atoms. The understanding of the photophysics and photochemistry of these products could permit the design of complexes with appropriate metals and ligands chosen for individual applications. Following a synthetic strategy consisting on reactions between acid heterometal complexes and basic gold precursors we have succeded in synthesizing supramolecular assemblies formed via acid-base stacking, which display tunable luminescence or selective and reversible sensitivity to Vapour Organic Compounds (VOC?s) (2-5). In this sense, in accord with previous Mössbauer studies carried out in the gold precursor complex [AuR2]- (R = C6F5), the basic properties of this and related materials have been employed as building blocks of supramolecular assemblies in their reactions with complexes in wich the metallic centers act as lewis acids as, for instance, Tl(I) or Ag(I) (6). For instance, in the case of silver, by reacting equimolecular quantities of [NBu4][Au(C6F5)2] with AgClO4, in acetone, a solid of stoichiometry [Au2Ag2(C6F5)4(OCMe2)2]n is obtained. The polymeric nature of this material in solid state is confirmed through X-ray analyses (figure 1). It consists of polymeric chains formed by repetition of Au2Ag2 moieties linked through short gold-gold interactions. Nevertheless, in solution, the nature of this polymeric materials was still a matter of controversy and, in this case, the optical properties have been shown as useful tools in order to obtain information. Thus, while dilute acetone solutions of this complex give a emission coming from pentafluorphenyl localized ??* excited states, in accord with the presence of isolated tetranuclear Au2Ag2 units, when the measurements are done at different and higher concentrations, a band that does not obey the Lambert-Beer law appears. This deviation is consistent with molecular aggregation in solution of these units through gold-gold interactions, and a clear correlation between the emssion wavelength and the structure in the solid state and in solution is shown (figure 2). DFT calculations accord with the observed experimental behaviour and show the nature of the orbitals involved in each transition.

Oct 1, 2003

By Frands Jensen, Erik Eriksson

"Haldor Topsoe’s Wet gas Sulfuric Acid (WSA) technology has been proven in a number of industries converting sulfurous gasses to concentrated sulfuric acid. In the metallurgical sector plants have been delivered handling SO2 gasses from copper, zinc, molybdenum, and lead ore. WSA has high energy efficiency and allows autothermal operation from feed gas strengths as low as 3.0% (volume). Recent variants of the WSA process have been developed that allow very high SO2 conversion efficiencies of over 99.9%. This paper describes the technology, its advantages and industrial achievements.The WSA technology is well suited for production of concentrated sulfuric acid of commercial quality from the sulfur dioxide (SO2) gas that inevitably emerges from the metallurgical processes. Some of the features that make the WSA technology attractive for this application are:- High SO2 conversion rates (up to 99.99%)- High energy efficiency leading to a low autothermal point (~ 3% SO2)- No need for gas cooling and drying to produce concentrated sulfuric acid- No production of waste- Very low cooling water consumptionThis paper describes the WSA process principles and highlights features that make this process attractive for handling SO2 gases."

Jan 1, 2014

By M. Tanaka, H. Narita, T. Fuchikami, K. Morisaku, K. Nagao, T. Yoshida, K. Kuroda

The effect of various N-substituents on the performance of amide-containing tertiary amine compounds in the extraction of Rh(III) from HCl solutions was investigated to optimize the structure of these compounds for industrial use. It was found that N-2-ethylhexyl-bis(N-di-2-ethylhexyl-ethylamide)amine and tris(N-di-2-ethylhexyl-ethylamide)amine, which have long, branched alkyl chains, were suitable for Rh extraction, because they were soluble in a practical diluent (80 vol% n-dodecane?20 vol% 2-ethylhexanol) and stable against highly concentrated HCl/Rh solutions, and showed high selectivity for Rh(III) over Pd(II) and Pt(IV).

Jan 1, 2014

By Peter J. Franklin

"Short-term mine planning of open pits is an activity that has historically been carried out by hand. Typically, the use of computers has played little part in this type of mine planning. This paper describes the objectives and the procedures involved in short-term mine planning, comments on the type of computer systems available, and describes in detail a computer-aided short-term planning and scheduling system known as STEPS.IntroductionThe mine planning department of any o pen-pit mining operation performs a wide variety of different tasks. However, their primary concern is the preparation of detailed long-and short-term mine plans. These mine plan s will define the long-term operating strategies and definitive everyday working plan s for the ongoing development of the open pit.In this day and age, when operating costs have spiralled upwards due to inflation , and product revenues have decreased due to depressed economies and poor markets, it is vitally important for all aspects of the mining operation, including mine planning, to be efficient and cost effective.There are numerous options available for planning engineers when generating a mine plan. A cost effective mine plan must investigate all these options and select the optimum. When using manual planning techniques, it is often impossible to evaluate all the available options. To do this, and to produce an optimum mine plan, a computer is required.This paper discusses mine planning, with emphasis toward the short-term plan and comments on how the processes may be computerized. It also describes in detail, a computer software system called STEPS, which has been designed as an interactive graphics, computer-aided short -term mine planning and scheduling tool."

Jan 1, 1985

By Michel David

"The usual complaint of mines is that grade does not match exploration expectations. Quite often, more tons are mined than expected but at a lower grade. This can be seen as dilution. Geostatistics can help predict which dilution can be expected both in terms of grade and tonnage for different mining methods.The usual vocabulary of geostatistics speaks of block distribution; block variance, size effect, information effect, all terms which say very little to the practitioner. In f act, all this can be rephrased in terms of dilution .In this paper, the following is presented - an example which shows how reserves change with the size of selection units and number of samples taken, and tables which show the dilution that are bound to happen when dealing with the commonly encountered log-normal distribution. Finally, the paper shows how grade tonnage computations should be made in the case of an arbitrary distribution. IntroductionGeostatistics progresses more and more rapidly if one judge s by the number and quality of papers published in Mathematical Geology or at APCOM meetings. More and more case studies describing successful applications are published (David et al., 1986)(Kwa and Mousset-Jones, 1987). It is estimated that more than 270/0 of the gold mines around the world use geostatistics. There is still, however, a lot of resistance from the remaining 73%. Geostatistics has more formulae and equations than it needs to reach year 2000. We will be well into the third millenium before all the models available now are actually used. The progress may come in the form of finding better ways to present known statistical results and getting away from the jargon of geostatisticians. One example may be in trying to explain how we can answer the most common plea of the mining industry: production grade is not what was expected in the feasibility study."

Jan 1, 1988

By T. Alan O'Hara

"The decision to invest capital in developing a mine and constructing a mineral processing plant and services is usually made after a feasibility study shows &apos;that the estimated future cash flow from mine operations will yield an adequate return on the estimated capital expenditures.The actual return on investment may differ substantially from that estimated in the feasibility study, because of the probabilities of errors in estimating capital costs, ore reserves, operating costs, mineral revenue and operating productivity. This paper outlines the R.S.S. (root sum of squares) risk analysis procedure of computing the overall probability of the actual project D.C.F. (rate of discounted cash flow), differing from that estimated in the feasibility study.Variation in Project D.C.F.It is assumed that a feasibility study of the project has been completed which has defined the estimated values for all the project parameters, such as ore reserve tons and grade, capital cost, concentrate recovery, metal revenue, daily milling capacity and operating costs.The financial analysis of the mining project will have determined that the cumulative cash flow will yield an expected D.C.F. on the capital cost if all project parameters attain the estimated values. If, however, the actual value of any parameter varies from that estimated, the actual project D.C.F. will vary from the estimated D.C.F. Risk analysis methods attempt to determine the overall effect of probable variations in the estimated values of all project parameters on the D.C.F. of the mining project. This overall effect is expressed as a probability profile, which shows the likelihood of actual D.C.F. values greater or less than that estimated.Thus, a completed risk analysis of a mine project, with an expected D.C.F. of 15.51%, would display the characteristics shown in the preceding diagram."

Jan 1, 1982

By Mitchell Gordon

"In almost all thickener applications the highest possible solid/liquid separation efficiency is what is desired by the user. There is a trend in the industry due to monetary restraints and environmental pressures to look at ways to extract this maximum performance by either retrofitting existing thickeners or installing the most cost effective new thickener. This paper looks at some of the common problem areas and presents a range of solutions developed by Outokumpu Mintec in North America and outokumpu's subsidiary Supaflo Technologies Pty. Ltd.The Emerging PictureAfter many hours of discussions with a large number of plant personnel over the last two years a picture began to emerge regarding current thickening operations in the industry. Initially, it seemed that everybody had their own unique process problems and therefore needed a correspondingly unique solution. Looking more closely at all the cases and the ideas that we had either implemented or suggested, it gradually became apparent that the majority of operators all had one and the same process need ....""Better Separation Efficiency""The range of operational problems that were uncovered in the survey were much more varied than expected and often were not even considered initially to be thickener problems. Often, it was only after the rejection of many solutions to the problem, generally due to capital cost, that the actual cause of the problem was looked at and found to be a thick-ener.A summary of the problems that have so far been identified is presented in Table 1. They are subdivided under three major categories of environmental, process and paste fill to highlight the wide range of mining activities that can be affected by poor thickener performance. These seem to be the major areas where the need for better separation efficiency is rooted."

Jan 1, 1995

By Y. Wang

In this paper, the tribological and electrochemical corrosion properties of Al2O3/polymer nanocomposite coatings were studied using a micro-hardness test, a single-pass scratch test, an abrasive-wear test, and finally an electrochemical technique such as potentiodynamic polarization measurement, The coatings containing Al2O3 nanoparticles showed improvement in scratch and abrasive resistance compared with polymer coatings; this improvement is attributed to the dispersion hardening of Al2O3 nanoparticles in polymer coatings, Corrosion test results showed that the embedded Al2O3 nanoparticles in the polymer matrix do not sacrifice the corrosion resistance of the polymer itself.

Jan 1, 2005

By Robert A. Gault, T. Scott Ercit, Mehmet F. Taner

"Abstract -Vanadium mineralization occurs in oxide-rich horizons within the layered gabbro zones of the upper parts of the Bell River Complex, Matagami, Québec and the Lac Doré Complex, Chibougamau, Québec. The vanadium-rich horizons are well defined on the ground and in aeromagnetic surveys by their high magnetic susceptibility; consequently, magnetic susceptibility can be an indicator of vanadium mineralization. The main oxide minerals are ilmenite and titanian magnetite, containing 20% to 70% of volume and the ratio of titanian magnetite to ilmenite is relatively constant, ranging from about 1:1 to 2:1. Their sizes are less than 5 µm to greater than 1 mm to 2 mm, occurring as coarse- to medium-grained subhedral crystals intergrown with cumulate silicate minerals (plagioclase, pyroxene, etc.). Electron microprobe analyses indicate that the ilmenite grains are mineralogically and compositionally homogeneous and have low V contents (average 0.18% equivalent V2O5). In contrast, the titanian magnetite grains are inhomogeneous, consisting of trellisworks of ilmenite lamellae in Ti-poor, V-rich magnetite [less than 2 wt% TiO2, and 1.41% equiv. V2O5 (1.16% V2O3) for 20 analyses]. Thus, the magnetite is the principal ore mineral of vanadium; it hosts vanadium in the form of V3+, not V5+, as is commonly and erroneously reported. We have also devised a flowchart for the beneficiation of vanadium-titanium ores. Sommaire - La minéralisation de vanadium se trouve dans des horizons riches en minéraux oxydés de la partie supérieure des zones de gabbros lités des Complexes de la Rivière Bell, Matagami, Québec et du Lac Doré, Chibougamau, Québec. Des horizons riches en vanadium ont été bien définis sur le terrain et dans les levés aéromagnétiques par leur susceptibilité magnétique élevée; conséquemment, la susceptibilité magnétique est l’indicateur directe du contenu en vanadium. Les principaux minéraux oxydés sont l’ilménite et la magnétite titanifère, contenant 20% à 70% du volume et le rapport de magnétite titanifère à ilménite est relativement constant, allant d’environ 1:1 à 2:1. Leur dimension varie de 5 µm à plus grande que 1 mm à 2 mm, apparaissant sous forme de cristaux subidiomorphes, de grains grossiers à médiums, intercroissant avec la gangue silicatée (plagioclase, pyroxène, etc.) de la texture de cumulat. Les analyses à la microsonde électronique montrent que les grains d’ilménite sont minéralogiquement et chimiquement homogènes avec un faible contenu en V (moyenne 0.18% équiv. V2O5 ). Contrairement, les grains de magnétite titanifère sont hétérogènes, contenant des lamelles d’ilménite en "trellisworks"; ces grains sont pauvres en Ti et riches en V pour la portion magnétite de la magnétite titanifère [surtout contenant moins de 2 wt. % TiO2, et en moyenne 1.41% équiv. (1.16% V2O3) pour 20 analyses]. Ainsi, la magnétite est le principal minerai de vanadium; elle renferme du vanadium sous forme de V3+ et non de V5+, tel qu’il a été communément et à tort rapporté. Nous avons aussi défini un "flowchart" pour la bénéficiation des minerais de vanadium-titanium."

Jan 1, 1998

By Kenneth L. Graham

Horizontal directional drilling from existing underground workings will greatly reduce, if not replace, surface exploration drilling. Diminishing ore reserves along with increasing difficulty in acquiring access and permitting of drilling surface holes requires a change in procedure. The length and direction of the required long holes is site specific, but once determined could be quickly mobilized. Data would be available for a much more timely evaluation without any surface disturbance and required reclamation issues. Preplanned directional drilling from underground will also provide an evaluation of already inconsistent uranium deposits located under surface terrain that is inaccessible to surface drilling.

Aug 1, 2010

By B. Farabi Khoshmehr

In the present study the effect of Silicate Sodium oxidation agent concentration and Plasma Electrolytic Oxidation (PEO) treatment time were investigated on properties of oxide layer on Aluminum alloy. The phase composition and surface morphology of PEO films were evaluated through x-ray diffraction (XRD) and scanning electron microscopy (SEM). Pin on Plate abrasive machine were used to investigate of were resistance of coating. The results showed that oxide layer which formed on Aluminum surface consist of high temperature a- Al?O? and ?- Al?O? phases. The diffraction peak intensity and percentage of these phases were increased by increasing silicate sodium concentration. Microscopic studies revealed a porous surface for PEO coating. This was affected by silicate sodium concentration and oxidation time. The wear test results showed that the weight loss of PEO coating was reduced due to improvement of their wear resistance.

Oct 1, 2011

"These guidelines set out information on timely disclosure of news releases which are intended to provide, existing shareholders and potential investors, factual information on which a reasoned investment decision can be made.Consider the problems and concerns raised by the following hypothetical news releases:Natural Resource Company""The Company has recently optioned a large and exciting gold property near the ""XXX"" gold discovery area. In describing the property, the Company's independent consultant has said: ""The favourable location of, and some of the results of prior work done on the property give the Company a worthwhile mineral exploration opportunity .... "". The Company proposes to expeditiously conduct a sizeable exploration program on the property as soon as the appropriate financing has been arranged.""Non-Resource Company""Based on discussions with several European countries, the Company anticipates that it will have orders to ship over 200,000 crates of widgets to those European countries over the next two years. These orders, which considerably exceed the Company's forecasts for the first year, represent a projected profit to the Company in excess of $1,000,000 over the next five year period.""GuidelinesTimely disclosure news releases are intended to provide, to both existing shareholders and potential investors, factual information on which a reasoned investment decision can be made. National Instrument 43-101 Standards of Disclosure for Mineral Projects provides requirements for disclosure of a scientific or technical nature for a mineral resource company.The examples do not provide sufficient detail and are misleading because material information is omitted. The following guidelines should be observed when preparing a news release:"

Jan 1, 2003

By S. Rash Ahmadi

One of the most important elements in power plants is rotors and repairing the damaged rotors is very important in view point of economics. One of the most complicated problems in power plants is increasing of stiffness of the turbine rotors. This problem which occurs mainly due to thermal shock or rubbing makes to exit damaged rotor from service. These elements can be repaired effectively by heat treatment methods. Tempering heat treatment is the most common solution for straightening of damaged rotors but it requires having good knowledge about heat treatment parameters (temperature and time) and their affects on fundamental properties of rotors. In this article, a suitable method is introduced in order to modify the increased stiffness in journal part of rotors due to martensite transformation, using heat treatment tempering process.

Oct 1, 2011