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By J. D. Steenkamp, G. E. Williams

Keywords: Ilmenite, titania slag, pig iron, rutile, zircon Located on the eastern shores of South Africa, 180 km north of Durban, Richards Bay Minerals (RBM) produces approximately 2.0 million metric tonnes of product annually making RBM a leading producer of titania slag, high purity pig iron, rutile and zircon. Heavy minerals are extracted from the nearby dunes by dredging and concentration on a floating gravity separation plant, followed by separation of the ilmenite, rutile and zircon at the mineral separation plant located at the smelter site. The ilmenite is processed through an oxidizing roast followed by magnetic separation and is then partially reduced to an 85 per cent TiO2 slag in one of four six-in-line a.c. electric arc furnaces. The slag is milled and then classified into two product sizes suitable as a raw material for both the sulphate and chloride pigment processes. The high quality iron produced during the reduction process is further processed to produce various grades of low-manganese iron. Around 95 per cent of the products are exported, yielding a world market share of about 25 per cent of titania slag, rutile, high quality pig iron, and zircon.

Jan 1, 2006

By S. R. Dindarloo

"Truck-shovel systems are the dominant material loading and haulage machinery in open pit mining operations. Optimal selection, sizing, and allocation of this capital intensive equipment is highly desirable for both achieving production targets and improving the mine’s economics. In this study, discrete event simulation technique was applied for modeling material transportation in Golegohar open pit iron ore mine in Iran. Direct observation of the material loading and haulage for duration of three months resulted in statistical modeling of the operation in the form of probability distribution functions. These probability models were used as the inputs of a stochastic simulation model constructed in GPSS/H simulation language. The model was validated through comparison with the actual operation and was used to test different what-if scenarios and sensitivity analysis of the current system. Some modifications in the number of trucks, shovels, and dispatching strategies were proposed. Simulation resulted in considerable improvements in the mine’s production and economics.INTRODUCTION There are three different mechanisms of discrete, continues, and hybrid material transportation in open mines, including but not limited to: i) in-pit crusher and conveyor belts (hybrid), ii) slurry piping (continues) and iii) truck-shovel system (discrete). Although, each mechanism has its advantages, the truck-shovel system is the dominant method of material loading and handling in open pit mines owing to its high production rate, excellent flexibility, relatively low operating and capital costs, and good maintainability. General objectives of optimal equipment selection include: i) meeting the long and short term requirements of production rates, ii) human & equipment safety, iii) environmental protection, and iv) economic operations (Figure 1).The two most important decision factors on a truck-shovel system selection and sizing are the equipment geometry and size. Geometry (equipment width, weight, turning radius, swing angle, etc.) is mostly controlled by mine’s designs and layouts, as well, as operational constraints. After selection of a favorable geometry based on the constraints; the next step is to select the equipment manufacturer. Once the geometry and manufacturers are selected; the next step is to decide on models (e.g. Bucket size) and required number of each unit"

Jan 1, 2015

By Juan C. Diaz, Juan P. Carmona, Manuel Z. Salgado, Oscar J. Restrepo

The “Teaching Kids” project is an educational initiative for young people and children from elementary schools. It is carried out by Mining, Geological, and Environmental Engineering students from the SME Student Chapter of the Universidad Nacional de Colombia, Medellin. The primary purpose of the Teaching Kids project is to share knowledge about geosciences and mineral resources in a didactic and attractive way, emphasizing the importance of identifying the use of minerals in daily life and responsible and sustainable mining in our society. Furthermore, this project aims to promote the importance of pursuing geoscience majors in the new generations and improve the mining industry’s public perception. Different methodologies related to early childhood education are implemented, such as gamification, in which the dynamics of games are adapted during the development of workshops to teach and learn in an active and motivated environment. Furthermore, the Montessori Method is used. It implements textbooks, sensory mineral boxes, and presentations to allow learning through experimentation itself (Montessori 2003). The implementation of this methodology has been successful; it has shown high engagement, participation, and retention of the basic concept of geoscience and mining.

Feb 1, 2025

By C. Fairhurst

Most of the papers designated as being within the topic of underground storage at this Symposium are concerned with aspects of radioactive waste isolation. Although this is, unquestionably, an important international application of underground storage, and one involving a considerable number of research investigations, the subject of underground storage is indeed much broader. Several major international conferences have been devoted exclusively to it. Applications include storage, under a range of temperatures and pressures, of oil and liquefied petroleum products, compressed air, heat, foodstuffs of various kinds, hazardous and 'nuisance' industrial by-products, and a variety of special applications, both civilian and military - some in use, others proposed. Storage may be in caverns excavated specifically for the purpose, exhausted mines may be adapted for storage or, in some cases, the material to be stored may be injected under pressure into the pore spaces of porous-permeable formations at depth. A variety of rock types and geological environments are used, e.g. excavations in salted or domal salt, where long-term creep closure of the openings is a concern; massive granite, where fluid loss through fissures may be important. Cavities may have spans of several tens of meters, and there is interest in achieving still larger excavations. As would be expected, this breadth of underground storage applications introduces a similarly broad range of questions in rock mechanics and rock engineering. The report will review these questions and recent developments in rock mechanics research, computational procedures, and design applications - and will also discuss the opportunities for a still greater range of applications of underground storage to current industrial and social problems.

Jan 1, 1989

By R. Curtis

To achieve compliance with 2015 EPA Tier 4 Final regulations, which permit only around 10% of Tier 3 particulate matter (PM) and NOx emissions, a number of technologies are being implemented. Use of a fuel borne nanoparticle combustion catalyst reduces the level of PM and unburned hydrocarbons exiting the combustion chamber, alleviating the burden on downstream exhaust after-treatment systems. The impact of an iron-ceria combustion catalyst (GO2) on carbon oxidation kinetics and on diesel engine emissions is presented. The iron-ceria nanoparticles catalyze carbon oxidation at lower temperatures and increase the oxidation rate by a factor of 18 at 400 °C. Engine tests on a generator powered by a John Deere Model engine and field tests on a Cummins ISC 330 tractor truck and CAT 3508B propulsion engines are presented. Use of GO2 resulted in a reduction in PM10 (particulate matter under 10 um) emissions of up to 26% and a hydrocarbon emission reduction of up to 41%. NOx emissions did not increase in these trials and the amount of change depended on engine type. Application of this fuel borne technology for emissions reductions in mining equipment offers significant benefits.

Feb 27, 2013

By H. C. George

This bulletin deals with prime movers, power-transmitting machinery, and the surface equipment and methods used to pump oil wells. It does not discuss geological problems nor the methods and equipment used in drilling or at flowing oil wells. Much of the presentation is by photographs and drawings which are described in the text. Underground equipment and methods for pumping oil wells will be discussed in a later publication of the Bureau of Mines.

Jan 1, 1925

By Ryo Sasai, Takeshi Itakura, Haruki Imaizumi, Hideaki Itoh

"Emission of industrial wastewater containing harmful oxoanions is one of the serious problems on account of its toxicity and the environmental pollution, especially caused by boric, phosphinic, arsenic and antimonic species. In this study, we developed a novel treatment technique of such polluted-water by hydrothermal mineralization. The treatment is “Geomimetic” method for precipitating oxoanions in aqueous media as natural ore resources by using hydrothermal treatment with calcium salts mineralizer. The treatment made it possible not only to detoxify the polluted-water, but also to recover the calcium minerals such as Ca2B2O5·H2O, Ca5(AsO4)3(OH), etc. Concentration of each ion in treated-water was lower than that of effluent standard in Japan. Moreover, the residual concentration of each ion was independent of the initial concentration, but it depends only on the solubility of the formed mineral under hydrothermal condition. Therefore, the hydrothermal treatment could be recommended as one of the treatment techniques of polluted-water.IntroductionVarious oxoanions such as boron and arsenic oxo-anions have high toxicity against human health and the environment. They are important resources, however, for plating or advanced material manufacturing industries[1-3], from which the wastewater containing these oxoanions is generated every day. An appropriate treatment is often required for industrial wastewaters to attain national effluent standards of Japan (NESJ, B: 10 mg/dm3, As: 0.1 mg/dm3). On the other hand, there is no production of arsenic and boric resources in Japan, and they are expected to be recycled. Therefore, the establishment of a system for the removal and recycling of arsenic and boron from wastewaters is of global significance.Several methods to remove them from aqueous media have been already reported by using adsorption[4], electro-coagulation[5], membrane separation[6-8] and biological techniques[9]. However, these methods have the following problems because of their stability in water. (1) Removal yield is low, especially for tri-valent arsenite ion (AsIIIO3 3-) and borate ion. (2) The applicable concentration range is narrow. In addition, the used adsorbents or collected residues after treatments are sill hazardous wastes, so that they must be treated by a proper method. But, it is very difficult to convert them to recyclable resources at most industrial plants. These problems are caused by the difficulty to recover these oxoanions as stable solid precipitates with low solubility in water. The establishment of recycling system of these hazardous compounds will be one of the world-important issues, especially, in Japan, which is poor in natural resources. On the other hand, compounds that contain high arsenic concentrations and are insoluble in water, are often found in natural minerals, for example, as haidinglite (Ca(AsO3OH)·(H2O) or Johnbaumite (Ca5(AsO4)3(OH)). This fact suggests that nature has an ability to produce insoluble As-bearing minerals. Similar phenomena can be found in case of boron, antimony, etc."

Jan 1, 2008

By David Penswick

Despite anecdotal evidence to the contrary, the mining industry is not in decline. Rather, the world?s largest mining companies are among the most consistently profitable companies in any industry. In many cases, profitable mining companies have been built around a few large scale, long life mines. These criteria for success ? size and long life ? have led to the current preference for deposits that can be exploited using open pit methods. However, developments in the science of block caving have resulted in this mining method achieving costs and productivities that are competitive with the largest open pits, while achieving widespread applicability. One implication of the low costs and widespread applicability of block caving is that some current open pits are possibly too deep.

May 1, 2003

By Toby Mayo, Tassos Grammatikopoulos, Massoud Aghamirian, MARK FEDIKOW

The Zoro pegmatite project in east-central Manitoba occurs 20 km east of the historic mining town of Snow Lake. A composite sample (Master Comp) was prepared fromthree pegmatite zones within Zoro Dyke “D1” including the North, Central, and South Zones for mineralogical analysis and heavy liquid separation (HLS). The mineralogical examination was conducted on a subsample crushed to ca. P80 of 600 μm to determine the overall mineral assemblage, liberation of spodumene, and assess the potential recovery of spodumene by flotation. XRD and QEMSCAN results show that the sample consists of spodumene (10.5%), quartz (29.3%), plagioclase (29.0%), K-feldspars (21.3%), micas (5.1%), tourmaline (2.9%), and Fe-Mn-phosphates (0.1%). Spodumene is well liberated (88%), but also forms complex particles (7%), and middlings with quartz (4%). Liberation of spodumene increases from 81 in the + 600 μm to 95%in the − 106 μm size fraction. Liberation of quartz, feldspars, and micas account for 89%, 94%, and 83%, respectively. Electron probe micro-analyses and LA-ICP-MS showed that the average Li concentration is 3.7% in spodumene, 2196 ppm in micas, 1001 ppm in tourmaline, and 115 ppm in K-feldspars. Thus, spodumene accounts for 96%, micas 2%, Fe-Mn phosphates 1%, and both K-feldspars and tourmaline for < 1% of the total Li in the sample. The mineralogical data indicate the potential to recover spodumene by flotation with minimal Li losses due to other than spodumene carriers. Heavy liquid separation was conducted on the Master Comp which was crushed to − 6.4 mm, while the − 600 μmfractionwas removed fromthis test. The coarse fraction − 6.4mm/+ 600 μmwas subjected to HLS tests with eight heavy liquid-specific gravity cut-points (2.65 to 3.10 g/cm3). HLS indicates that it is possible to produce a high-grade lithium concentrate (close to 6% Li2O) after the rejection of iron silicates with magnetic separation.

Sep 16, 2020

The U.S. economy continued to expand during 1986, although at the slowest pace since 1982 when the current business expansion began. Real gross national product (GNP) grew about 2.6%, slightly below 1985 growth but significantly below that of 1984. The continuing expansion was fueled predominantly by rising personal consumption expenditures as well as growing government purchases of goods and services. Fixed investment, although positive, failed to grow at the rate of the overall economy. The trade deficit, which increased more than 30% over the record 1985 level, continued to depress economic growth despite significant declines in the price of petroleum and the value of the dollar. On a more positive note, domestic employment continued to grow--increasing over 2 million from the 1985 level--and inflation and interest rates declined. The unemployment rate dropped slightly to 7.0%. Of direct importance to the minerals-producing industries, expenditures for consumer and producer durables as well as investment in residential construction each grew faster than the overall economy, but investment in nonresidential structures fell more than 10% from the 1985 level. The low level of real capital spending declined about 3% in 1986, following strong gains in 1985 and in 1984. Capital expenditures for new plant and equipment bottomed out in the second quarter and expanded in the third and fourth quarters. The decline in the first half of the year was partially attributed to uncertainty arising from the then-proposed tax bill. Also, there was little impetus for corporations to invest in new capacity since factories were operating at less than 80% of capacity during most of the year, in part because of continued competition from imports.

Jan 1, 1987

"These guidelines, implemented in 2003, were recommended by the Diamond Exploration Best Practices Committee established by the Canadian Institute of Mining, Metallurgy and Petroleum. The guidelines are applicable to public companies and their consultants reporting diamond exploration results.“The guidelines are referenced in the Companion Policy of NI 43-101 with a statement that disclosure regarding the reporting of diamond exploration sampling results should conform to them.”Reporting GuidelinesThe following guidelines have been recommended by the Diamond Exploration Best Practices Committee established by the Canadian Institute of Mining, Metallurgy and Petroleum. These guidelines are applicable to public companies and their consultants reporting diamond exploration results.In respect of these guidelines, Diamond Exploration Results are results derived from the initial activities undertaken to investigate a diamond bearing prospect or deposit, to generate tonnage, grade and value estimates that cannot be classified as a Mineral Resource or Mineral Reserve. They do not address the earlier stage reporting of geophysical, geochemical or kimberlite indicator mineral results.Public reports of Diamond Exploration Results relating to mineralization not classified as Mineral Resource or Mineral Reserve must address the confidence limits of the result and contain sufficient information to allow a considered and balanced judgement of the significance of the results.The objective of these guidelines is to assist public companies and consultants in making appropriate disclosure of diamond exploration results by reporting in a manner which is:Uniform within the diamond exploration industry; Consistent with reporting from other industry sectors .Comprehensive .Unambiguous .The guidelines are not prescriptive. Materiality is the overriding principle that determines the information that should be disclosed. However, where a company or consultant deviates from the guidelines, the disclosure or technical report should state the extent to which the guidelines have not been followed, and the reasons for the deviation.The guidelines do not in any way replace jurisdictional reporting requirements (For example, the requirement for Canadian reporting issuers to comply with Canadian Securities Administrators National Instrument 43-101 by having technical disclosure endorsed by a Qualified Person as defined in that legislation)."

Jan 1, 2003

By Gerald M. Ellis

Exploration for gold .deposits on Hispaniola has taken place sporadically over the years but has expanded in the past decade. There are veintype, disseminated, alluvial and elluvial deposits. Investigations were previously undertaken in Haiti by combined Haitian, Bureau of Mines, and UN geological teams at Grand Bois Limbe(Milot) and Cap Coq areas. Later studies were conducted at the Miches and Moncion districts. Gold occurrences were reported in quartz, silicic-barite veins and gossans. An important deposit ?at Pueblo Viejo is? a disseminated type where extraction is taking place in the oxidized zone. Exploration by Japanese and West German firms with local geologists are described in this paper together with Pueblo Viejo, Miches, Restauracion, Milot, and Meme ?areas where occurrences are known. Copper deposits with associated gold va1ues are also described. These include vein deposits in Central Cordillera and disseminated deposits at Terrier Rouge and Blondin.

Jan 1, 1989

?Four-wheel, skid-steer, rover developed for CSA ?U-chassis for payload accommodation ?Passive geometric suspension ?Max speed 13km/hr ?Remote workstation ?275kg payload capacity ?On-board processor, IMU, motor encoders ?5.2kW-h battery capacity

May 1, 2013

By Frank J. Purcell

“Down The Hole” (DTH) hammer drilling is often necessary to advance the casing during pile construction where the test bores have determined difficult drilling conditions with obstructions such as boulders, cobble and glacial till. The use of compressed air to operate DTH hammers in foundation drilling has been a contentious point in many regions of the world due to its potential to disturb the ground around the pile being constructed. There are many examples of damage to adjacent building foundations where compressed air exiting the pile being drilled disturbed the subsurface around the building’s existing piles. This paper looks at the use of compressed air in DTH hammer foundation drilling and the move towards controlling the exhausted air to avoid over drilling the pile, causing potential damage to nearby piles. Simulated models of air flow penetration into the soil of different configurations of drill bits are discussed to highlight design changes employed to better control the air during the drilling process. A case study of the construction of a water-tight pipe pile wall for a building’s underground parking structure is studied to demonstrate the potential of DTH hammer foundation drilling where the air is fully controlled.

Nov 1, 2022

By ERIK CHARRIER, ADITYA JUGANDA, Jürgen Brune, Gregory Bogin, Patrick Maier

Confined explosions are a major risk in underground coal mine operations. Depending on confinement, ignition location and obstacles in the flame path, methane explosions can transition to detonations. This research focuses on explosion experiments in a reactor with diameter of 71 cm and length of 30.5 m, along with developing the corresponding computational fluid dynamics (CFD) model that captures the observed flame behavior. The results show that the 2D and 3D CFD models are able predict the experimental flame front propagation velocity, but the 3D model shows more explicit conformity than the 2D model.

May 1, 2024

By G M. Mudd

Mine tailings represent one of the two largest sources of mine waste from the minerals industries (the other being waste rock). Given the problems of declining ore grades and growing production, tailings generation is increasing exponentially across the global mining industry. Common practice is for mines to build large containment dams to store tailings during operations, which are then rehabilitated following mine closure. At some sites, however, the controversial practices of riverine or marine dumping of tailings is still practiced. As recent tailings dam failures have shown, there are legitimate questions being raised about the long-term viability of leaving tailings above ground due to the risks of collapse and failure. At present, it is rare for mines to emplace tailings back into former mine voids following mine closure, most commonly into a former open pit mine void (although a fraction of the tailings may be used for underground mine backfill, this is minor in scale). The approach of in-pit tailings has numerous advantages, such as inherent physical stability, low to negligible acid and metalliferous drainage (AMD) risks, as well as allowing more productive use of formerly mined land. In tropical areas where surface repositories are prone to leakage with potential for AMD and widespread dispersal of radionuclides (in the case of uranium mining), in-pit management provides particularly strong advantages – thorough hydrogeological studies are required, however, to address residual groundwater contamination risks and to establish sound, long-term environmental monitoring regimes for groundwater quality and subsidence issues. This paper presents a study of in-pit tailings management and compares it with surface repositories established in a tropical climate. The comparisons lead to the conclusion that, at least under tropical conditions, in-pit tailings management should be considered as world’s best practice – especially for radioactive uranium tailings.

Aug 8, 2011

By L. C. So, S. Faucher, S. Mostaghel, D. Sauter, S. -Y. Oh, S. K. Lee

"Molten material from pyrometallurgical furnaces is tapped at high temperature, carrying a large amount of heat. Traditional handling methods of slow air cooling or water granulation do not allow for the recovery of heat from slag and matte. Furthermore, water granulation adds an inherent safety risk of explosions. Recently, there have been numerous studies into processes attempting to recover waste heat. However, most of them have never been commercialized due to numerous challenges including scalability, cost, low heat recovery efficiencies, and difficulties in heat utilization. Ecomaister-Hatch has recently developed and commercialized a reliable and simple dry atomization system that allows for heat recovery while eliminating the use of water. Comparisons of pilot and commercialized dry atomization and heat recovery technologies will be presented and challenges of these technologies will be highlighted.INTRODUCTION Slag has traditionally been regarded as an undesired waste product from smelting operations with slag management focused on removal and disposal of “waste”. Over 500 million tonnes of slag are produced per year, carrying with it ~220 TWh of energy (Barati, Esfahani, & Utigard, 2011). Depending on the process, the energy content of slag ranges from 10-90% of the total energy input (Barati, 2011, Rodd, 2010). There has therefore been great interest in recovering energy from slag. Slag handling methods can broadly be classified into three categories: (1) dumping and slow cooling, (2) wet granulation and (3) dry granulation. As discussed below, only dry granulation routes are amenable to heat recovery. Slag dumping involves the slow cooling of molten material and crushing of the resulting solid. In this process, slag is dumped on the ground directly from furnaces or transferred to slag pots that are moved by rail or haulers and then dumped on the ground. The molten material is left to cool and solidify until it can be broken and handled by heavy machinery."

Jan 1, 2017

By O. P. Hood, R. H. Kudlich

When a gasoline locomotive is used in a mine there is danger of the noxious gases of the exhaust vitiating the air, but if enough air is circulating in those parts of the mine in which the locomotive is used, these gases are so diluted that they are rendered harmless, and the health of the workmen is not affected. In some mines the use of gasoline locomotives is impracticable, though in the majority of mines where they have been tried they have proved to be safe and economical. To determine the limitations that should surround the use of these machines in mines so that they shall not be detrimental to health and so that their economic advantage may be retained, it is necessary to ascertain the volume and the character of the exhaust gases and the amount of these gases that may be safely allowed in the mine air, and also to determine safe conditions of operation. The problem is primarily one of ventilation and like all ventilation problems must be intelligently computed to meet the conditions of each mine. The investigation described in this bulletin was undertaken 'by the Bureau of Mines in an endeavor to obtain exact information on some of the basal questions involved in the use of gasoline locomotives in mines, this investigation being one of many that the bureau has been conducting in its efforts to increase safety and efficiency in mining.

Jan 1, 1915

By N. Nišić, A. Cvjetić, V. Jovanović, D. Knežević, D. Nišić

The risks associated with operating water reservoirs and tailings storage facilities (TSFs) are different because of their different purposes, methods of construction and operation, and characteristics of the materials impounded and their flow behaviour. Regardless of the differences, these two types of structures are often put in the same category when it comes to risk assessment and the application of relevant methodologies, which may result in unrealistic outcomes. In this paper we investigate whether it is possible to apply the risk ranking methodology designed for water reservoirs to TDFs and overview the key differences between these two types of structures. We also provide a comparative analysis of the results obtained by conducting a risk assessment of the operation of a TSF, applying the method recommended by the International Commission on Large Dams (ICOLD), and analyse the results using the failure mode and effects analysis (FMEA) technique. It is concluded that a more realistic evaluation of risk levels can be obtained by adopting a systematic approach to risk assessment in accordance with the traditional risk definition on which the FMEA technique is based.

Nov 30, 2022

By A. E. Wraith, J. Protheroe Jones, P. J. Mackey

The world’s first copper electrorefinery started production in 1869 at Burry Port in South Wales. Built within the Pembrey Copper Works which had commenced smelting operations in 1849, the new refinery was based on principles described in the British patents issued to J.B. Elkington in 1865 and 1869. Refining principles and practices pioneered there were key to the foundation of modern electro-refining practice in what is now a dominant international industry producing over 16 Mt of electrical grade copper annually. This paper explores the background to this pioneering application of the new, early 19th century, science of “electro-metallurgy” and examines its links to the contemporary decorative electro-plating industry and to the shortcomings of 19th century fire refining. The beginnings and early years of the Pembrey electrorefinery are briefly discussed in relation to the quality, applications and pyrometallurgy of copper at the time. More than a decade would elapse before the birth of the electrical age: the Pembrey refinery may be seen as one of its vital precursors. Note: This paper was originally published as part of the Copper 2013 proceedings (A.E. Wraith, P.J. Mackey and J. (formerly R.) Protheroe Jones, “Origins of Electrorefining: Birth of the Technology and the World’s First Commercial Electro-Refinery”, paper in Electrorefining, Vol. V, Book 2, (Eds. R. Abel and C. Delgado), Cu 2013 International Conference, pp. 19-33, IIMCh, Santiago, Chile, 2013). It is reproduced here together with a new Appendix and supporting references that lists the year of commencement of the first electrolytic copper refinery by country, 1869 to 1956. It all, the year of the first electrolytic copper refinery established for 15 countries is included. These 15 countries now produce more that 70% of world refined copper (for 2018). INTRODUCTION In the 1840s, the new science of ‘electro-metallurgy’, a term coined by Smee in 1841 (Smee, 1841), was being adapted to the decorative electro-deposition of silver in a thin, bright adherent coating that was evidently equal in appearance to traditional silverware (Williams, 1976). Chief among innovative manufacturers of decorative objects who took up the new art of silver electro-plating was the acclaimed firm of G.R. Elkington and Co. of Birmingham, England. The company, which vigorously developed all aspects of electro-metallurgy for the decorative trade, entered the field of ‘electrotyping’, a technique in which the surface features of a mould are copied on an electro-deposited copper layer which, when stripped off, can be used to reproduce an imprint of the mould. In essence, it is a form of casting by electrodeposition, invented in 1837 independently by Jacobi in Russia (Pavlova, 1968) and Spencer in England (Wyatt, 1851).

Jan 1, 2019