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By Michel Aubertin

Les rejets miniers sont communément utilisés, depuis plus de 60 ans, comme matériau de remblayage des chantiers souterrains. Les roches stériles et les rejets de concentrateur sont employés comme remblais car ils sont disponibles sur les sites miniers à un coût réduit pour aider au support de terrain. Le remblayage des ouvertures est également avantageux car il permet de réduire la quantité de rejets entreposée en surface. Dans les mines souterraines, le remblai des chantiers doit aider à maintenir un espace de travail sécuritaire, tout en favorisant la récupération du minerai et le contrôle de la dilution. Il est alors essentiel d'évaluer précisément les pressions exercées par le remblai sur les murs et sur les barricades installées près de la base des chantiers. Dans cette présentation, des solutions existantes pour évaluer les pressions dans les chantiers sont brièvement revues. Les auteurs présentent ensuite des solutions analytiques récemment développées à cette fin, qui permettent de tenir compte du transfert des contraintes du remblai aux parois des chantiers et des galeries. Les solutions proposées, qui sont basées sur la théorie de l?effet d?arche, prennent en compte l'influence de la géométrie des ouvertures et de la position des barricades. La méthode de calcul permet aussi de calculer l?effet des pressions d?eau pour un remblai partiellement ou totalement submergé. Les solutions s'appliquent au cas d?un remblai récemment mis en place, alors que l?effet de la pression interstitielle ne peut pas être négligé, et aussi à plus long terme sous une condition drainée. Des résultats expérimentaux et des simulations numériques sont utilisés pour valider les équations proposées. Les résultats analytiques et numériques montrent notamment que la pression totale sur une barricade peut être grandement augmentée par la pression d?eau, tandis que la contrainte effective peut être réduite par les pressions interstielles (par rapport à la condition drainée ou sèche). On discutera aussi des implications pratiques de ces résultats pour l?application des remblais souterrains.

Nov 1, 2008

By I. M. Marshall

SOME years ago the writer had the opportunity to plumb a number of mine-shafts, each of which presented various conditions and difficulties. This afforded the chance to compare several methods of shaft plumbing in the light of ease and rapidity. This comparison led to the development of an adaption of the Weisbach, or approximate alignment, method, to three wires in a single shaft. Professor Weisbach, some time prior to 1850, introduced his method of shaft plumbing by triangulation on but two wires, and was the first to show that a triangle of very narrow shape is the best for this purpose. THE WEISBACH METHOD The two-wire method, using a Weisbach triangle, is described in several .English text-books on mine surveying and is used frequently in various parts of the world, but in Canada it is almost unknown. The writer has described an example of this two-wire method (1), but a brief resumé here may clarify the explanation of its application to three wires. In this two-wire method, instead of endeavouring accurately to align the instrument with the wires, it is set only in approximate alignment, and the small angle formed at the instrument is measured. This is expressed graphically in Figure l, where C represents the position of the instrument and A and B the positions of the wires. The sides of the triangle are measured as well as the angle ACB, and the angles at B and A are found by applying the Sine Rule or the formula

Jan 1, 1938

By R. A. L. Drew, F. Jalilian, M. Jahazi

Joining of superalloy Inconel 61 7 with a foil interlayer using transient liquid phase bonding (TLP) technique was studied. Inconel 617 is a solid solution, Ni - Cr - Co- Mo alloy with an exceptional composition of high temperature strength, oxidation, carburization resistance and thermal stability. In this investigation, two bonding temperatures, 1065°C and 1150°C, and two interlayer thicknesses with joining times varying from 5 minutes to 24 hours were employed. Experiments were carried out using nickel base interlayer (A WS BNi-3) with boron as the melting point depressant (MPD) element. Joints were characterized using optical microscopy, SEM, FEG-SEM, EBSD, XRD and microhardness. The results indicated that the rate of elimination of the liquid phase with increasing the bonding temperature, holding time and decreasing the thickness of the interlayer increased. The main precipitates in the diffusion layer had platelike and blocky morphologies for both bonding temperatures and all holding times.

Jan 1, 2006

By Frank Ebbutt

In this paper it is proposed to point out certain structural factors that; have an important bearing on gold deposition. The subject will be treated; more or less generally. Although the writer has had access to a great many; of Canada's gold mines he does not wish to take the liberty of discussing; details of any particular mine or mines; the aim will be to discuss controls; that are evident in many places.

Jan 1, 1954

By P. Homola, M. Karlík, M. Slámová

"Aluminum sheets (AA1199, AA8006, and AA5754) were processed by accumulative roll-bonding (ARB) in the temperature range from 20 to 350°C. The microstructure of the sheets was characterized by means of scanning and transmission electron microscopy and electron backscattered diffraction. Mechanical properties were monitored by hardness measurements and tensile tests. Increasing strain (number of ARB cycles) led to incremental development of lamellar microstructure with a decrease of the spacing between high-angle grain boundaries in the normal direction of sheets. ARB process produced an important increase of strength while maintaining thickness and relatively high ductility, without accenting of the anisotropy of mechanical properties of sheets. The level of hardening decreased with the processing temperature and at 300 and 350°C ARB caused even the softening of the material due to the recovery of the deformed microstructure or partial recrystallization during heating to ARB processing temperature.INTRODUCTION Accumulative Roll Bonding (ARB) is a technique of grain refinement by severe plastic deformation (SPD) proposed by Saito et al. (1999). One ARB cycle consists in sheet cutting, surface treatment, stacking of two pieces, heating (optional), and rolling with 50% reduction in thickness. Since the sheet thickness remains unchanged by this cycle, ARB processing can be repeated as many times as desired. The goal of ARB is to impose an extremely high plastic strain on the material, resulting in structural refinement and strength increase without changing specimen dimensions. After several cycles, ultra-fine grained (UFG) materials with high strength and relatively high ductility are produced. An advantage of this method is that it does not require any special equipment as other SPD methods such as equal channel angular pressing (ECAP) (Valiev & Langdon, 2006), high pressure torsion (HPT) (Valiev et al., 2000), or cyclic extrusion and compression (CEC) (Richert et al., 1999), but only a conventional rolling mill and so it is seen as an economically viable and industrially scalable processing route. ARB processing has been successfully applied to various kinds of metallic materials at room or elevated temperatures (Tsuji, 2005). Besides processing single metals and alloys, ARB has also been used for creating ultra-fine grained and nanograined metallic composites (Wu et al., 2010; Qu et al., 2014)."

Jan 1, 2018

By J. Kouam

Al-Si-Cu and Al-Si-Mg alloys are widely used in several applications. Although they can be produced near-net-shapes, products made of these alloys very often require some machining. The purpose of this study is to evaluate the machinability of A319 and A356 under TO and T6 conditions. The machinability was assessed using during dry drilling machining process and the machinability indexes used are the chip form, the chip breakability and the cutting forces. It is found that 319 and 356 exhibit different machinability behaviors, especially in the T6-condition in terms of forces requirements, chip breakability and chip segmentation. It is also found that both the microstructure of the workpiece materials and the machining conditions significantly affect the chip formation mechanism, and therefore, the machining parameters could be selected to promote a chip form that is easily manageable in production.

Jan 1, 2011

By C. E. Cairnes

The Slocan mining camp in Kootenay district; British Columbia; has long been noted for the great number of its silver-bearing deposits; and for the success that has; in many instances; attended their development. The orebearing area lies east of Slocan lake and mainly within a radius of 6 to 8 miles of the mining town of Sandon. Within this limited area 135 or more properties have shipped ore in quantities of from 100 tons or less to more than 500; 000 tons; and with a total value in silver; lead; and zinc ranging from a few hundred dollars to well over $10; 000; 000. Of the three metals; silver has easily ranked first in value; with lead second and zinc third. Zinc production; however; made slow progress in the early years; and with . the exception of the Lucky Jim mine; and a few others where high-grade ore could be readily hand-sorted; was a detriment to the silver-lead ores until improved methods of separation enabled it to take an important place in the mineral production of the Slocan.

Jan 1, 1954

By A. L. Holloway, N. M. Soonawala, L. S. Collett

"Since the late 1970s, a major R&D program has been under way in Canada to assess the concept of disposing of nuclear fuel wastes in deep plutonic rock. Atomic Energy of Canada Ltd . (AECL), a federally-owned corporation, has been given the responsibility of directing this research (Rummery et al., 1983).The Underground Research Laboratory (URL), constructed in a granite pluton 15 km east of Lac du Bonnet, Manitoba (Fig. 1) is a major component of the Canadian Nuclear Fuel Waste Management Program. A diverse geotechnical experimental program is being carried out during both the construction and operating phases of the URL. This program involves detailed geological mapping, rock mechanics and hydrogeology studies, and geophysical surveying, to characterize the rock mass surrounding the shaft, and it has been described by Simmons et al. (1983). As part of the construction-phase program, ground-penetrating radar (GPR) surveys are being carried out during excavation, in an attempt to delineate fractures both ahead of the excavation and behind the walls of the excavation. This paper presents the results of surveys performed during shaft excavation and describes a procedure for plotting the data.Ulricksen (1982) cites examples of radar surveys to evaluate surficial deposits, such as peat, sands and gravels, and cavity detection in subsurface hard rock. Fowler (1981) used radar for fracture and clay vein detection in coal seams.In Canada, pioneering work in GPR has been done by Annan and Davis since the mid-seventies (Annan and Davies, 1976). Their work concentrated on problems relating to permafrost in the Arctic ."

Jan 1, 1986

By Chris G. Dobson

Introduction The Britannia mine is at Britannia Beach, on Howe sound, approximately thirty miles from Vancouver. The first claims were staked in 1898, and a local company was formed at that time to develop them. In 1904, Mr. Grant B. Schley became actively interested in the property and in the following year the Britannia Mining and Smelting Company, Limited, was incorporated to operate it. This Company was taken over a few years later by the Howe Sound Company, Limited. The mine comprises five more or less separate ore-bodies, which have produced approximately 20,000,000 tons of ore to date. The East Bluff ore-body, with which the present paper deals, is well suited to large-scale mining by means of carefully placed powder blasts. It covers approximately an acre and lies in the slate footwall, in a bay produced by a fault. The hanging-wall side, on the west, forms the face of the Bluff glory-hole, which extends to the 1,200 level. A portion of this ore was available for breaking into this old glory-hole, below which four bulldoze chambers could quickly be built. Mining of this block is complicated by a very soft footwall, which 'runs' badly when broken. In stoping, care is taken to guard against the hazard of dilution by deliberately leaving a small portion of ore on the footwall. Some of this will undoubtedly be lost, but it is hoped to recover a fair amount of it after the major drawing is completed. The deposit occurs in a greenstone which has been highly silicified following brecciation. The chief minerals are chalcopyrite, sphalerite, and pyrite. Concentrates of copper, zinc, and pyrite are made at the mill. The average grade of ore runs 0.7 per cent copper, 1.5 per cent zinc, and 0.03 oz. gold per ton. The rock, which is practically a chert, is extremely hard, but shatters well. Both in stoping and drifting, holes must be closely spaced and powder used generously. Development When development work started in the East Bluff, there were no raises and only one drift on each level in this section of the mine. After blocking out the ore by thorough diamond drilling, a production of two thousand tons per day was set as a goal. To obtain this tonnage from so small an area required a great deal of carefully planned and well timed development work.

Jan 1, 1935

By M. S. Hedley

"The Lucky Jim mine is at Zincton in Slocan mmmg division; on the Kaslo-Nakusp branch of the Canadian Pacific railway. It is owned and operated by Zincton Mines; Limited; a subsidiary of Sheep Creek Gold Mines; Limited. The mine is far in the lead in the production of zinc in the Slocan. Its recorded production from concentrates and shipping ore was 102; 260; 191 pounds of zinc to the end of 1945.GENERAL GEOLOGY With the exception of acidic dykes the rocks near the Lucky Jim mine belong to the Slocan series, which is Triassic in age and consists principally of argillaceous rocks. It disconformably overlies greenstones of the Triassic Kaslo series about 3 miles to the northeast, and is cut by granitic rocks of the Nelson batholith 5 miles to the southeast.The sedimentary rocks in this area are best referred to on the whole as slates. They lie within the more fissile basal part of the Slocan series. The term 'slate belt' conveniently distinguishes this area of rocks characterized by slaty cleavage from the more massive argillites that are more characteristic of the Slocan as a whole. The contact between the slaty and massive argillites lies ½ mile southwest of the mine."

Jan 1, 1954

By R. Kamguem

The surface of a mechanical part plays an important role in determining performance in service. The presence of scratches left by the cutting or tearing of the material on the surface of the workpiece supports the concentration of stress and strain. This article presents the experimental study for high speed milling of the aluminum alloy 7075-T6, using cutting tools different by the nose radius and coatings (TiCN, TiAIN, TiCN + A12O3 + TiN). A multi levels factorial design of experiment (DOE) and statistical analysis was used. The roughness parameters investigated are Ra, Ra, Rv, Rc, Rsm, and Rk. The results show that the feed rate, the types of coatings and the geometry of the cutting tools have the most significant impact on the surface roughness profil. Surface finish charts according to feeds and cutting speeds were established for each tool tested.

Jan 1, 2011

By E. G. Joe

"Recent trends in Canadian mineral processing were reported in seven areas of interest covered by seventeen technical papers at the 1976 Annual Meeting of the Canadian Mineral Processors, held at Energy, Mines and Resources' Camsell Hall, Ottawa. New milling equipment included the Enviro-Clear thickener, large-volume Outokumpu flotation machines and abrasion-resistant polyurethane screens. Grinding experiences from a variety of milling operations were reported. Opportunities for increased sizing and grinding efficiency were presented. Flotation control by digital computer and by chemical additions were described in two mill operations. Slurry pumping and sampling techniques were described for various operations. Environmental control in milling was reported concerning dust suppression, arsenic removal and tailings disposal. Several aspects of gold milling were described by the most recently commissioned gold mine and by CANMET. Potash operations were reported showing the similarity of processing and process control to that of metallic minerals."

Jan 1, 1976

By Arnfinn F. Prugger, Fritz F. Prugger

"The Saskatchewan potash beds are overlain by a number of water-bearing formations. There are water zones in the footwall as well. These aquifers created difficulties during the construction of shafts to the potash beds at 1()(}() m depth, and they pose a continuous threat to the safe and efficient operation of potash mines in the province.The first shafts to be sunk in Saskatchewan encountered major problems during shaft sinking. Of the 17 potash shafts started in the province, five had major water inflows during shaft sinking or after production startup, and one was abandoned because of water problems. The biggest obstacle encountered during shaft sinking was a poorly consolidated sand-shale-clay-siltstone unit commonly called the Blairmore Formation, which occurs at a depth of about 500 m. The initial problems with shaft sinking were overcome in the 19605by using European methods of freezing and the installation of cast-iron tubbings or a double-steel lining through water bearing horizons.From the start of production in the early 19605, operators have been aware of the ever-present hazard of potential water inflows into mine openings from permeable units in both the hanging wall (carbonates of the Dawson Bay Formation which occur 15 m to 50 m above the mining level) and the footwall (carbonates of the Winnipegosis Formation which occur 50 m to 150m below). This awareness has been reflected in conservative over-all extraction rates and mining layouts specific to local conditions. In spite of this consciousness, a number of water problems have occurred in operating mines. These have resulted in everything from simple increases in expenditure to the shut-down of one mine in 1987.In this paper a history of water problems in the Saskatchewan potash industry is given, followed by a summary of measures that are now commonly used to avoid these problems. A description of each inflow event is given, and the attempt is made to analyze the causes of each occurrence. Based on what was learned f rom each event, suggestions are made to prevent future water inflows into potash mines."

Jan 1, 1991

By Jianzhong Liu

Based on the characteristics of overburden rock strata movement, surface ground subsidence and casing deformation and failure, a tension-shear combination failure model of surface borehole was set up. The main controlling factors of the mining-induced deformation and failure of surface borehole were researched with this failure model and the limit analysis method. The mining methods and geology conditions mechanics action mechanism to surface borehole and its time ?space evaluation rule was found. The surface borehole deformation and fracture rule were advanced. It provides theoretical support to optimizing layout, structure type, security measure and local casing protection of surface borehole.

Aug 1, 2013

By A. Saigal

The effect of temperature on the cutting forces during machining of alumina reinforced aluminum composites was investigated, Aluminum 6061, 10% Al2O3 reinforced composite and 20% Al2O3 reinforced composite were tested, A 5/8-inch diameter high-speed steel end mill, a Micro 100 TiN coated single edge endmill cutter and a two-fluted solid carbide insert cutter were used for tooling, The results, in general, showed an increase in the cutting forces as the temperature of the material increased, From the raw data, there are temperatures ranges in which the force data did decrease but they were insignificant with regards to predicting a downward trend. A regression analysis was used to understand which variables had the greatest affect on the forces being generated, The correlation and regression analysis showed that at 600 rpm (velocity: HSS- 98,2 sfpm, Micro 100 cutter - 78,5 sfpm, solid carbide cutter - 192,4 sfpm) the tooling, the workpiece material, built up edge, and temperature were statistically significant factors in the test, Tooling was a significant variable in all testing, The smallest forces recorded during machining were generated with the solid carbide two-fluted endmill cutter, Visually, the solid carbide tooling produced a better surface finish during the testing which made it the tool of choice, In addition, the force data proved that as the cutting speeds were increased, the cutting forces decreased.

Jan 1, 2005

By Charles W. Villiers

AS is well known, there are large and valuable deposits of coal in British Columbia, both on the mainland and on Vancouver island. These deposits are widely distributed over the Province. The chief sources of supply on the mainland are found in the Fernie and Princeton-Nicola districts and on Vancouver island in the Comox and Nanaimo districts. The coals range from a very high quality bituminous coal to lignite. On the Upper Skeena river there is said to be a very large deposit of anthracite or semi-anthracite, but this field has not been developed. Coal was first discovered in British Columbia on the north end of Vancouver island in the year 1835, but it was not until 1852 that coal mining was seriously undertaken by the Hudson's Bay Company at Nanaimo, where mining has been carried on continuously ever since that date. The production of coal in the Province continued to increase until the year 1910, when the annual output reached its peak at 3,100,000 tons and a total of 7,800 men were employed in the industry. Since 1910, the production has dropped steadily until, in 1934, only 1,347,000 tons of coal were produced and less than 3,000 men were employed. This continued decrease in production has in no way been caused by lack of coal reserves. It has been due entirely to curtailment of markets. I do not propose to discuss coal mining practice in British Columbia, where we have all sorts of mining conditions, including submarine mining. There is no lack of coal supplies for either industrial or domestic purposes, nor is there likely to be any shortage of coal in the Province for many generations. We have our mining troubles, which increase the cost of production, but there are no insuperable difficulties to prevent the extraction of a large and increasing supply of coal. Our main difficulty-in fact our only serious difficulty-is to find a market for our output, and we must consider means which can be evolved not only to conserve our existing markets but also to expand them, at any rate within the boundaries of Canada. I will therefore confine my remarks chiefly to the all-important factor of Markets for our coal.

Jan 1, 1936

By Louise Corriveau

Exploration strategies have traditionally considered felsic gneiss complexes of the Canadian Shield sterile. This paradigm is challenged with the discovery of extensive granulite-facies Cu-Au, Fe oxides-bearing hydrothermal systems in the 1.4 Ga Bondy and 1.5 Ga La Romaine volcano-plutonic complexes of the Grenville Province. Early identification of magnetite-rich units in association with meta-exhalite and pelite-like units was key to targeting the search for mineralization, protolith information and indicators of pre-metamorphic hydrothermal activity during regional surveys of these frontier terrains. Textural evidences for a volcano-plutonic setting were found. There remained, however, numerous impediments to the recognition that the ubiquitous magnetite-laden units and associated aluminous gneiss were hydrothermal in origin. Many metamorphic reactions form magnetite at the amphibolite to granulite facies transition, and hydrothermally-leached rocks resemble metapelite or migmatitic restite, while carbonate alteration zones may look like marble or calc-silicate rock. Non-typical metamorphic mineral assemblages, modes and colours arise when hydrothermally-derived rock types are metamorphosed. These effective markers served as tools for reliable field identification of hydrothermally-altered rocks. In our case-studies, we traced pre-metamorphic hydrothermally-driven Fe-oxide precipitation in association with sericitization, albitization, pyrophyllite alteration, chloritization, and B enrichment by mapping unusually high contents of (1) magnetite or hematite, (2) biotite, (3) albite, (4) sillimanite, (5) orthopyroxene or phlogopite with cordierite, and (6) tourmaline or kornerupine. The unveiled garnetite, tourmalinite, and aluminous gneiss had assemblages that vary according to metamorphic grade and composition. To assess if high mode of Fe-Mg-Al phases resulted from partial melting (restitic residue) or metamorphism of hydrothermal rocks, we compared leucosome mineral assemblages, shape and amount with that expected of in situ partial melting reactions. In both areas there is no compelling evidence for these units to be restites. In contrast, the presence of lapilli in garnet-cordierite-sillimanite gneiss, though extremely rare, constitutes conclusive evidence for extreme pre-metamorphic high-sulphidation alteration of a volcanic protolith, while Fe-oxides or sillimanite-bearing nodules and veins record a less pervasive alteration. Geochemical research on element mobility and mass balance calculations further testified of an hydrothermal origin for these gneisses. The magnetite-rich units, together with calc-silicate rocks, garnetite, hornblendite, albitite among amphibolite, provided effective guides to sites of fluid discharge and led to the discovery of Cu and Cu-Au showings. With the presence of highsulphidation alteration, these features suggest early Cu-Au VHMS-type alteration halos within a predominantly felsic composite volcano-plutonic arc setting for both case-studies. Evidences for subsequent F-driven orthomagmatic fluid activity are also present.

May 1, 2003

By Forrest A. Kerr

The subject of the Coast Range batholith and its eastern contact zone needs no introduction to British Columbia mining men. Because of its reputed potentialities, this zone has aroused much interest. Because it has touched the pockets of the people by actually producing dividend-paying mines, it has been able, more particularly in certain isolated sections, to retain and accentuate that interest. However, the Stikine River section of the zone has never had the good fortune to have a mine developed, which, through profits or lack of profits, could create such interest. The Cassiar district, beyond the Stikine River area, has been a lure to the prospector for over half a century and was still strong enough in the last few years to attract close to a million dollars in capital and labour. All of this has passed through the Stikine river area, has looked at it, and ignored it. Sufficient interest has never been aroused in the area to bring forth an effort to see what is there, in spite of the fact that it belongs to the same zone in which some of our richest mining camps are located. Because the contact zone of the Coast Range batholith has long been recognized as an ore producer of considerable potentiality, the Geological Survey some years ago formulated a plan to map as much of this area as possible in order to assist in promoting its development. This plan has been furthered during the last fifteen years whenever opportunity presented itself, until today a fairly large part of the area has been covered. The work which has been done on the Stikine during the last two years is the beginning on what is the largest remaining gap in the general plan.

Jan 1, 1928

By N. Saracoglu, J. P. Golightly, R. H. Wallis, J. J. Brummer

"The McClean uranium deposits are located 11 km west northwest of the Rabbit Lake Mine. Their average grade is 1.8 % U3O8 , and they contain 6. 350 tonnes of uranium oxide in seven pods of variable grade and mineral assemblage. They are hosted by both basal Athabasca Group and the regolith developed on the underlying crystalline basement. The major mineral facies are: sulphide, arsenide, 'bleached', and hematite, with the important uranium minerals being coffinite, uraninite and pitchblende. Abundances of carbon and sulphur isotopes are consistent with their derivation from pyritic graphite in basement gneisses. Isotopes of oxygen and hydrogen suggest equilibration at temperatures of about 200°C. Ar39/ Ar40 age determination of illite associated with ore suggest mineralization began about 1300 m.y. ago and that significant alteration had ceased by about 1170 m.y. ago though Pb/ U data suggest the deposits continued to evolve into the Mesozoic.IntroductionThe McClean deposits lie on the eastern side of the Athabasca Basin of northern Saskatchewan where they are part of a cluster of uranium deposits lying west of Wollaston Lake (Fig. 1). The general stratigraphy is schematically portrayed in Figure 2 which emphasizes that mineralization is hosted by both the Athabasca Group and the underlying regolith and also that the deposits are preserved at depth and have not suffered from preand post-Pleistocene weathering and erosion. This circumstance, combined with their simple shape and the presence of seven separate zones of mineralization (pods) allows a description, based on over 450 fully cored drill holes, to be made of the wide variation in chemistry, grade, alteration patterns and position relative to the sub-Athabasca Group unconformity. Ar39 / Ar40 age determinations have been made of illites associated with regolith, Athabasca Group and mineralization and studies are in progress on C, S, 0 and H isotopes of mineralized material and host rocks. Only some of these data have been published; Brummer et al., (1981); Golightly et al., (1982); Bray et al., (1982); and Saracoglu et al., (1983). The only other published data on McClean geology are by Tremblay (1982, 1983)."

Jan 1, 1986

By Christina Graf

A synthesis of colloidal gold shell particles with a silica core is described. Small gold nanoclusters were attached to the functionalized surface of colloidal silica particles. Reductive growth and coalescence of these clusters lead to the formation of a closed gold layer. By variation of the thickness of this gold layer and the radius of the shell it is possible to adjust the plasmon resonance of the gold shell particles over the whole visible and infrared region of the spectrum. The optical properties of the particles made are in good agreement with theoretical calculations for coreshell particles. Due to their low polydispersity these gold shell particles form in solution large crystals with submicron lattice constants. It is also possible to produce hollow gold shells by dissolution of the silica core. A new method to coat the silica core gold shell particles with an additional outer silica shell is also presented. This allows due to a reduction in the Van-der-Waals forces to make more permanent dried crystals and facilitates functionalization of the particles for use in various photonic applications.

Oct 1, 2003