Hellenic Geosphaera Exploration (I.G.M.E.) Special Issue March 2008

Institute of Geology and Mineral Hellenic Geosphaera Exploration (I.G.M.E.) Special Issue March 2008

CONTENTS

Newsletter of the Institute of Geology and Mineral Exploration (I.G.M.E.) Introductory address from the General 1 L.E.P.L. Supervised by the Ministry Director of the I.G.M.E. of Development (L. 272/76) Director General Prof. A. Georgakopoulos Hellenic industrial minerals and rocks: 2 current research performed by the I.G.M.E., Editorial Board: by N. Kaklamanis EurGeol Alecos Demetriades The modern filler laboratory of I.G.M.E. 6 Dr. Irene Zananiri Alexandra Zervakou Potential industrial applications of vein- 7 Athanasios Makris quartz resources in Northern Hellas, Dr. Michalis Patronis by N. Arvanitidis Dr. Athanasios Hatzikirkou Mineralogical - Petrographical laboratories 14 Editing of this issue: Applied mineralogy for the efficient 15 EurGeol Alecos Demetriades exploitation of wasted magnesite Run-Of- Fotini Chalkiopoulou Mine fines, by F. Chalkiopoulou, M. Grossou-Valta, S. Karantassi

I.G.M.E. Central Offices: “LITHOS”: The accredited ornamental stone 20 1, Spirou Loui, str. quality control laboratory of the I.G.M.E. Olympic Village, Entrance C 136 77 Acharnae Hellenic marble through the ages: an 21 overview of the marble producing areas and Tel. +30 210 2413000 the stone sector of today, Fax +30 210 2413015 by K. Laskaridis http://www.igme.gr/ The contribution of petrography to the 27 Edition distributed free of charge. evaluation of carbonate aggregates for Articles represent the views of the author(s). concrete production, by M. Dimitroula Quotation / reproduction is permitted only with proper citation of the source. Radioactivity control of building and 31 decorative materials, by F. Pergamalis, Communication: D.E. Karageorgiou, A. Koukoulis, [email protected] D. Persianis

An overview of the industrial mineral 35 resources of Greece, by I. Marantos, K. Hatzilazaridou

MARMIN STONE 2008 44 ISSN: 1791-4523

INTRODUCTORY ADDRESS FROM THE GENERAL DIRECTOR OF THE INSTITUTE OF GEOLOGY AND MINERAL EXPLORATION

ellenic Geosphaera is a quarterly Magazine of the Institute of Geology and Min- eral Exploration (I.G.M.E.), published with the aim to inform the public of the H activities and important work the Institute has and continues to perform in the geoscientific field. The natural environment is directly connected to the geological structure of our country, which the I.G.M.E. systematically studies since 1950.

The Special Issue of the Magazine that you have in your hands is dedicated to Indus- trial Minerals and Rocks, and presents a small part of the research performed at the National and European level in this field. It is published to commemorate the occasion of the I.G.M.E’s participation as local co-organiser of the 19th International Industrial Minerals Congress and Exhibition (IMC).

The Institute shows a remarkable activity in the field of Industrial Minerals and Rocks. Further to identifying and studying occurrences over the country by applying the innovations offered by modern technology, it is currently active in the following activities:

• Compilation of G.I.S. data bases and maps that will include past and current information on deposits of industrial minerals and rocks;

• Geological mapping at various scales (1:500 – 1:50,000) of selected areas of interest;

• Development of know-how for the exploitation of industrial minerals, residues from marble exploitation, aggregates and other raw materials for the production of marketable products;

• Evaluation of raw materials for cement manufacture;

• Development of tools for the after-closure beneficial use of abandoned quarries;

• Evaluation of new deposits (e.g., zeolites, pozzolanas), and

• Compilation of inventories of wastes from quarries/mines, as well as other wastes, such as fly ash.

It is worth mentioning at this point that the organisation of the 19th IMC in Hellas coin- cides with the actions that have been undertaken for the “International Year of Planet Earth” (www.yearofplanetearth.org).

The “International Year of Planet Earth 2007-2009” aims “to capture the people’s imagination with the exciting knowledge we possess about our planet and we see that knowledge used to make the Earth a safer, healthier and wealthier place for our chil- dren and grandchildren”.

The General Director

Prof. A.N. Georgakopoulos

HELLENIC INDUSTRIAL MINERALS AND ROCKS: CURRENT RESEARCH PERFORMED BY THE I.G.M.E.

Nikos Kaklamanis Mining Engineer ([email protected]) I.G.M.E., Division of Mineral Processing

Current Industrial Mineral Research 1. FRAMEWORK AND OBJECTIVES Operational Programme Currently, the research carried out Industrial Minerals, not only the “Competitiveness” by the I.G.M.E., for the location and ones examined currently, but also those studied in the past by the Support Framework evaluation of Hellenic Industrial Min- I.G.M.E. III erals and Rocks is included in the project entitled “Industrial Minerals The project is subdivided into ten – Innovative Technologies – New separate sub-projects, each one Products”, funded by the Community covering a specific industrial mineral Support Framework III, Operational commodity of Hellas, and specifi- Programme “Competitiveness”. The cally: (a) Feldspars, (b) Quartz, (c) project, with a total budget of 1.1 Zeolites, (d) Vermiculite, (e) Oli- million Euros, has the following prin- vinites, (f) Garnet, (g) Industrial cipal objectives: Minerals for cement industries, (h) • Rational exploitation of mineral Clays, (i) White Carbonates, and (j) resources via the development of Fly-ash. As mentioned above, all environmentally friendly tech- project results will be included in a nologies/methodologies for the Data Base, which shall also incorpo- utilisation of Industrial Minerals, rate all relevant data concerning by-products and wastes. Hellenic Industrial Minerals & Rocks.

• Reinforcement of the local indus- In addition, three activities—tasks, tries’ competitiveness by improv- namely (a) a G.I.S. data base for ing production procedures, elimi- Hellenic Industrial Minerals, (b) ap- nating production costs and pro- plication tests regarding the use of moting new high-added value commercial product types. Industrial Minerals for the neutralisation of effluents, and (c) study of • Development of new products, zeolite-vermiculite ash as a soil im- new markets and new fields of prover, were subcontracted and im- applications. plemented by private companies, • Utilisation of by-products and which are supporting the research wastes in order to produce low- activities undertaken by the I.G.M.E. cost raw materials. within the aforementioned sub- • Utilisation of Industrial Minerals in projects. environmental applications, in- In the following paragraphs, the cluding elimination of environmental impacts. main objectives and work carried out in each sub-project are concisely • Design and development of a discussed. The major exploration G.I.S. Data Base for the Hellenic

Page 2 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

CURRENT RESEARCH ON INDUSTRIAL MINERALS

and research sites, covered by the project are prising mainly magnetic separation of composite presented schematically on the map of Figure 1. samples and acid treatment, as well as calcination tests on non- magnetic products, (d) collec- 2. BRIEF DESCRIPTION OF tion of two bulk samples, each of 20 tonnes SUB-PROJECTS weight, and finally (e) pilot plant test-work.

2.1. Feldspars 2.3. Zeolites

This sub-project aims to contribute to the devel- The research is carried out in Thrace (Northern opment of innovative and environmentally Hellas, Rhodope and Evros Prefectures) and the friendly technologies for mineral processing of Prefectures of Arkadia and Lakonia in Pelopon- feldspathic raw materials. The proposed tech- nesus. The aim of this sub-project is to evaluate nologies will be applied on different important the natural zeolite deposits, occurring in the types of Hellenic deposits, such as pegmatites, aforementioned areas, in terms of their techni- tuffs, rhyolites and granites, in order to evalu- cal and economic feasibility for the production ate the feasibility and technical efficiency of of materials appropriate for (a) the treatment- corresponding cases, for the production of high purification of potable water, (b) treatment of grade and high added value commercial prod- liquid effluents for removal of heavy metal ucts with parallel elimination of environmental (such as Pb, Cd, Cu, Cr, Ni), (c) improvement of impacts. Major tasks of the project were: (a) soil in combination with other raw materials, geological mapping of an area of 6 km2 (scale such as fly ash and vermiculite. The research 1:5,000) and a second of 0.1 km2 (scale performed to date included the following: 1:200), (b) collection of 150 samples, (c) labo- • Geological mapping of an area of 3 km2 ratory measurement and testing, comprising (scale 1:5,000), a second of 10 km2 (scale mainly magnetic separation and flotation test 1:5.000) and a third of 32 km2 (scale work, (d) collection of 5 bulk samples, each of 1 1:50.000) at Petrota (Evros Prefecture, tonne weight, (e) pilot plant test work, and fi- Thrace, N.E. Hellas), as well as compilation nally (f) market research. of geological sections of 30 km total length, • Collection of 100 hand samples of zeolite for 2.2. Quartz laboratory research and mainly the measure- The aim of the sub-project is to develop benefi- ment of their ion exchange capacity, ciation methods for the treatment of high purity • Compilation of an inventory of 400 fountain- vein quartz reserves from Northern Hellas, in head sites, and collection of 400 water sam- order to produce ultra–pure grades of quartz. ples located in the Peloponnesus area. The specific research focuses on extracting low– • Collection of a composite bulk sample of sodium quartz deposits and developing new about 15 m3 that was mainly used for testing technologies for efficient removal of fluid inclu- in different agricultural applications. sions, which contain a relatively high percent- 2.4. Vermiculite age proportion of sodium. The following tasks Within the framework of this sub-project, re- have been completed within this project, to search work was undertaken in Central Mace- date: (a) geological mapping of an area of 19.5 donia, Northern Hellas, in order to evaluate km2 (scales 1:20,000, 1:10,000 and 1:5,000) known serpentinite bodies for their vermiculite and a second of 1 km2 (scales 1:1,000, 1:500 potential. Furthermore, samples of raw and ex- and 1:200), (b) collection of 190 hand samples, panded vermiculite were tested as effluent representing 31 research areas in Central and processors and in agricultural applications. Northern Hellas, (c) laboratory test-work, com- Briefly, the tasks accomplished comprise (a)

Page 3 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

CURRENT RESEARCH ON INDUSTRIAL MINERALS

N geological mapping of an area of 1 km2 (scale Drama 1:5,000), (b) collection Kavala of hand and bulk sam-

ples, (c) expansion test Veria Chalkidiki work on the bulk sample, (d) application tests by using the expanded vermiculite firstly to achieve Larissa the growth of high val- ued crops, and secondly in greenhouse and hy- droponically grown plants. Finally, raw, as Kefallonia well as expanded vermiculite, were tested for ATHENS their appropriateness in Zakynthos environmental applications, and specifically for the removal of heavy metal from industrial effluents (plating and tan- Milos Yali ning industries), as well

as the improvement of LEGEND potable water supplies. Pozzolana Olivinite 2.5. Olivinites Zeolite Feldspar Crete The main objective was Garnet Clays to evaluate the olivinite Quartz potential of dunite/ Calcium Carbonates (Filler grade) Vermiculite hartzburgite bodies in Fly ash 100 km the Vavdos and Vourinos Figure 1. Schematic presentation of the areas (Chalkidiki and current investigation sites for Industrial Minerals and Rocks in Hellas. Grevena Prefectures re- spectively), as sources for the production of nes bulk sample from the Vavdos Public high quality olivine sand for castings, other than Mine. Mn-steels, and as an abrasive. The work accom- The bulk sample was subject to pilot crushing plished to date included the following: and screening for the production of grades, ap- i) Geological mapping of an area of 2 km2 propriate to industrial testing in the above men- (scale 1:5,000). The mapping concerned tioned applications, with hitherto positive re- the Vavdos Public Mine and the Chromio sults. village area; 2.6. Garnet ii) Eight drill-holes of 450 m total length in the Vavdos and Vourinos areas to esti- Limited research has been accomplished within mate the size of the corresponding depos- this sub-project, covering mainly economic ge- its; ology aspects, and more specifically statistical iii) Collection of hand samples and a 13 ton- evaluation of garnet occurrences in the areas of

Page 4 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

CURRENT RESEARCH ON INDUSTRIAL MINERALS

Svoula in the Chalkidiki Prefecture, as well as cium carbonate content and high whiteness validation exploration research on Serifos Island measurements) additional tasks were per- in the Aegean Sea. formed in the studied areas, including geological mapping and estimation of reserves. 2.7. Industrial Minerals for the Cement Industry 2.10. Fly Ash

The research conducted was initially focused on Although fly ash does not comply with the geo- the location of pozzolanas in the areas of East- logical definition of “Industrial Mineral” (a natu- ern Macedonia and Thrace, Central Macedonia, rally occurring substance), it was included in as well as on Crete Island. Finally, it was re- this project as a research theme, mainly due to stricted in Central Macedonia, where geological its potential industrial applications. The aim is mapping was carried out on an area of 10 km2 to develop environmentally friendly methodolo- and a hundred samples collected for examina- gies for exploitation of fly-ash, as well as bot- tion of mainly their pozzolanity. tom-ash, produced from the lignite electric power generation plants, as soil-improvers in 2.8. Clays agricultural applications. Within the project, an The aim of the specific sub-project was the lo- inventory of the fly- and bottom-ash wastes cation of clay mineral deposits to be used in the was compiled, providing thus relevant data for ceramic industry, and as land fillings in waste the electric power plants of Ptolemaida and disposal sites. The tasks performed covered the Amindeo in Northern Hellas, and Megalopolis in broader areas of Central Macedonia (Northern Peloponnesus in Southern Hellas. In total, 220 Hellas), Epirus (N.E. Hellas), Thessaly (Central fly ash and 25 bottom ash samples were col- Hellas), and Peloponnesus (Southern Hellas) lected. Bulk samples were also taken in this and included the following work (a) Geological sub-project; 50 fly-ash samples of 50 tonnes mapping of an area of 80 km2 (scale 1:50,000), each, and 10 bottom-ash samples of 12 tonnes (b) collection of 480 hand samples, (c) evalua- each. Hand samples underwent extensive labo- tion of the characteristic features or each sam- ratory studies, while bulk samples were tested ple, (d) collection of bulk samples, (e) industrial as soil improvers for agricultural purposes, as testing of bulk samples in ceramic factories, and well as neutralisation of acid soil. (f) selection of the most interesting areas to be studied on a pilot scale. 3. FUTURE WORK

2.9. White Carbonates All the aforementioned sub-projects are near to The research aims to locate resources of white completion, given that they are funded by the carbonate materials of an appropriate quality Community Support Framework III Programme, for the requirements of the Chemical Industry with a deadline at the end of this year. At the (paints, paper, plastics). Although areas such as current stage, interim reports are being pre- the Ionian Islands of Lefkada and Zakynthos pared and submitted. Accordingly, the final were initially included in the project, two areas technical reports are to be completed by the were finally studied: (a) the Vermion Mountain end of the year. The project’s major results will in Imathia Prefecture (Northern Hellas), and (b) be communicated to the relevant authorities, Crete Island (Southern Hellas). Geological map- according to the rules of the Operational Pro- ping was carried out over a total area of about gramme “Competitiveness”. of 125 km2 (1:20,000) in both areas studied. The collected 125 samples were subject to laboratory measurements and testing. For the high quality specifications of raw materials (high cal-

Page 5 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

THE MODERN FILLER LABORATORY OF THE INSTITUTE

DIVISION OF MINERAL PROCESSING ([email protected])

Figure 1. Partial view of the Filler Laboratory. 1c 1a: Spectrophotometer, VARIAN CARY 100

1b 1b: Particle Size Analyser, SEDIGRAPH

1c: Porosity, BET Surface Area, QUANTACHROME

1a 1d: Air Jet Sieve, ALPINE

1e: Abrasion Tester, AT 1000, EINLEHNER

1f: Colour Meter, LFM1 Dr LANGE

1e Figure 1

The Filler Laboratory of the I.G.M.E. is included in the In- dustrial Minerals Dept. of the Division of Mineral Processing (DMP). Its history, started in 1980 with an old Photovolt Reflectometer. Currently, it is fully equipped with new mod- 1d ern machinery and apparatus (Figs. 1-3), which, in con- 1f junction with other equipment of the DMP, as well as in combination with the significant experience and know-how of the personnel, give this Laboratory multi- functional capabilities.

Figure 2. • Field hand/bulk sampling, crushing, grinding & Besides simple meas- sieving Laser Diffraction, Particle urements & testing Size Analyser, CILAS 1064. • Ultra fine (d <5μm) grinding by jet milling 97 of materials, in- • Evaluation of Optical Properties (X, Y , Z, Rx, tegrated studies Ry, Rz, L*, a*, b*) [ASTM C-110-06, E313 / DIN 6174] for the exploita- • Abrasion Measurement, EINLEHNER tion of Mineral • Particle Size Analysis of Powders: Laser Diffrac- Raw Materials in tion, Sedigraph, N. Stokes [0.1 μm—500 μm] the field of Fillers • Porosity and BET Surface Area Measurements are feasible. • Evaluation of Carbonate Raw Materials according to EN ISO 3262.05 & EN ISO 3262.07 Presently, the DMP runs a sub-project entitled “Greek Or- namental Stones by-Products and Wastes Management and Utilization Study – Contribution in the Sector’s Viable Figure 3. Jet Mill. Growth”, with a budget of 285 thousand Euros. This project is funded by the Third Community Support Frame- work programme (CSF III 2003-2008), and is solely com- mitted to the exploitation of marble residues of Mace- donia and Peloponnesus for industrial applications, such as Fillers.

Page 6 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

POTENTIAL INDUSTRIAL APPLICATIONS OF VEIN- Q UARTZ RESOURCES IN NORTHERN HELLAS

Dr. Nikolaos Arvanitidis Economic Geologist ([email protected]) I.G.M.E., Regional Branch of Central Macedonia

Quartz Veins Abstract

High Purity Quartz Northern Hellas hosts a number of strategic Industrial Minerals, which make it an increasingly Grades important part of the Hellenic mining industry. Feasible quantities of vein-quartz resources of variable quality are hosted by gneiss and schist mainly in Pre-Alpine metamorphic formations. New Industrial Among the marketable end products a pure white variety is exported for polyester tile manu- Applications facturing (95% quartz and 5% polyester), a quartz powder (<200 mesh) is used in the filler and ceramics industries, and a significant amount goes to the local market for more conventional applications. Previously carried out RΤD projects focused on geological exploration and development of process flow sheets to produce high to ultra pure grades of Hellenic quartz. The geological exploration work was implemented systematically, and vein-quartz deposits of high quality and low impurities, were located and economically evaluated. The major task was removal of fluid inclusions for reducing the high sodium impurities. Innovative beneficiation techniques were developed to produce optical and electronic grade quartz. The high content of sodium, due to presence of very fine fluid inclusions (<20 μm), in the upgraded quartz products, prevents any electronic applications. The production of ultra-pure silicon metal, by using plasma smelting was not fulfilled, due to incomplete reduction of quartz in the constructed furnace. The quality grades achieved to date, may already place the Hellenic quartz in a good position in certain segments of the European and International market. However, it was concluded that the high-purity quartz compositions achieved should be further beneficiated to new marketable products and industrial applications.

Περίληψη

ΝΕΕΣ ∆ΥΝΑΤΟΤΗΤΕΣ ΒΙΟΜΗΧΑΝΙΚΩΝ ΕΦΑΡΜΟΓΩΝ ΧΑΛΑΖΙΑΚΩΝ ΦΛΕΒΩΝ ΑΠΟ ΤΗ ΒΟΡΕΙΑ ΕΛΛΑ∆Α: Στη Βόρεια Ελλάδα εμφανίζεται ένας δυναμικός αριθμός στρατηγικών Βιομηχανικών Ορυκτών, γεγονός που την καθιστά ιδιαίτερα σημαντική για την Ελληνική Μεταλλευτική Βιομη- χανία. Κοιτασματολογικά αποθέματα χαλαζιακών φλεβών, με διαφορετικά ποιοτικά χαρακτηριστι- κά, φιλοξενούνται σε γνευσίους και σχιστολίθους προαλπικών μεταμορφωμένων σχηματισμών. Ανάμεσα στα εμπορεύσιμα τελικά προϊόντα ένα υλικό υψηλής λευκότητας εξάγεται για την κατα- σκευή πολυστερικών πλακιδίων δαπέδου (95% χαλαζίας και 5% πολυεστέρας), ένα λεπτομερές προϊόν (<200 mesh) προωθείται στις βιομηχανίες πληρωτικών και κεραμικών και μια σημαντική ποσότητα πηγαίνει στην τοπική αγορά για περισσότερο συμβατικές χρήσεις. Στο παρελθόν, τα έργα Έρευνας και Τεχνολογικής Ανάπτυξης επικεντρώθηκαν στην κοιτασματολογική έρευνα και τη μεθοδολογία εμπλουτισμού για την παραγωγή υψηλής ως υπέρ-καθαρής ποιότητας ελληνικού χαλαζία. Η κοιτασματολογική έρευνα είχε σαν αποτέλεσμα να εντοπισθούν και να αξιολογηθούν αποθέματα χαλαζία υψηλής καθαρότητας, ενώ ο βασικός στόχος της μελέτης εμπλουτισμού ήταν η απομάκρυνση των νατριούχων ρευστών εγκλεισμάτων. Στο πλαίσιο του έργου αναπτύχθηκαν και εφαρμόσθηκαν καινοτόμες τεχνικές για την παραγωγή «οπτικής» και «ηλεκτρονικής» ποιό- τητας χαλαζία, εντούτοις οι παραμένουσες προσμίξεις περιεχόμενου νατρίου, λόγω παρουσίας μικρού μεγέθους ρευστών εγκλεισμάτων (<20 μm), καθιστά τα εμπλουτισμένα προϊόντα χαλαζία ακατάλληλα για ηλεκτρονικές χρήσεις. Η παραγωγή υπερκαθαρού μεταλλικού πυριτίου με την εφαρμογή τεχνολογίας πλάσματος δεν ολοκληρώθηκε, λόγω ατελούς αναγωγής του χαλαζία στον φούρνο που κατασκευάσθηκε για τον σκοπό αυτό. Σε κάθε περίπτωση, οι ποιότητες που επιτεύχθηκαν μέχρι σήμερα μπορούν να βελτιώσουν τη θέση του ελληνικού χαλαζία στη διεθνή αγορά. Το γενικό συμπέρασμα πάντως ήταν ότι χρειάζεται περαιτέρω ποιοτική βελτίωση του χα- λαζία σε μια προοπτική διάθεσης νέων εμπορεύσιμων προϊόντων και βιομηχανικών εφαρμογών.

Page 7 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

INDUSTRIAL APPLICATIONS OF VEIN-QUARTZ

1. INTRODUCTION project, the achieved quartz qualities, in terms of elemental chemical impurities (Fe, Al, Ti, Na The main research and development activities and K), appear feasible for the optics industry. on quartz, worldwide, concern today its applica- Two follow-up projects, financed by the Euro- tion in the production of microelectronic compo- pean Structural Funds Programme, aimed to nents, semiconductors, etc. The production of achieve further quartz upgrading, and new ultra-pure quartz, for the electronic and optical fields of industrial application. industries, has a strong future in Europe. For the next few years, a drastic increase in demand of ultra-pure quartz/silicon is expected for 3. VEIN GEOMETRY, MINERALOGY, a number of high-tech applications, such as DEFORMATION AND CHEMISTRY halogen bulbs, photovoltaic systems, high density integrated circuits, laser lenses, silica foam, 3.1. General optical fibres. The sole producer of ultra pure According to findings of the regional scale min- silicon in the world is located in N. Carolina eral exploration, accomplished within national (U.S.A.), and supplies the U.S.A., the Japanese and EU–funded projects, the Northern Hellas and the European markets. The development of mainland hosts numerous vein-quartz deposits. a new European industry for the production of Figure 1 shows the locations of discovered and ultra to high purity quartz will increase the com- known veins hosted by rocks belonging to the petition in the world market and eradicate the Serbomacedonian (SMZ), Pelagonian (PZ) and hitherto U.S.A. monopoly conditions. Rhodope (RZ) geotectonic zones. Quartz veins routinely occur in two-mica and biotite gneiss, 2. THE RESEARCH ACTIVITIES OF THE occupying extensional fractures, except for rare I.G.M.E. ON QUARTZ cases where they partly transect granite bodies. They form disrupted and boudinaged steeply Exploration for vein-quartz deposits, as well as evaluation of known pros- QUARTZ DEPOSITS AND pects, in Northern MINING IN HELLAS Quartz Veins BULGARIA (Macedonia, Thrace) and Quartz-Feldspar Pegmatites Central (Thessaly) Hellas, Quarries Mineral Processing Mill R Mine Wastes/By-products S H has been carried out by the E O R D B O O P I.G.M.E. within the frame- M E A Z C O work of a Brite–EuRam II E N D E O A N Programme project entitled L I M A O N “New Industrial Applica- P Z IA O P N Z A E tions for Quartz Deposits O I N K E O Z Indigenous to the Commu- O C N IR E C nity” (BRE2-CT94-1026) U M R (period 1995-1998). The H O D project aimed to develop P E O L P A E advanced beneficiation G B O E L N T techniques to produce ul- IA N Z tra-pure quartz/silicon for O N E high-tech application needs of the European market, using Hellenic vein-quartz as raw material. Along with the completion of the Figure 1. Simplified geological setting of vein-quartz deposits in Northern Hellas.

Page 8 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

INDUSTRIAL APPLICATIONS OF VEIN-QUARTZ

dipping (90o to 40o) bodies, striking NNW-SSE, filling, attributed to emplacement of veins in a concordant to regional schistosity. Veins meas- dynamic, tectonically active, environment; (b) ure from 30 up to 100 m in length, rarely reach brittle fracturing that took place after the ductile 300 or 500 m; thickness varies from 3 to 15 m. deformation, accompanied by cataclasis and re- Veins are composed chiefly of milky (Fig. 2) or crystallisation (quartz 2). yellowish-brown quartz (up to 99.5% by volume) with traces of white mica, sulphides, feld- Serbomacedonian raw quartz chemical composi- spar and iron oxides. tion shows ranges of Fe=1-28 ppm, Al=22-73 ppm, Na=12-37 ppm, K=4-28 ppm, Ca=11-40 Figure 2. ppm, Mg=4-10 ppm, Ti=1.4-4.8 ppm and Milky quartz veins hosted by SMZ Li=0.1-0.9 ppm. The problem, for electronic Gneiss, Kilkis Prefecture, Central Macedonia, Northern Hellas. high-tech applications of quartz, arises from a high Na contents, which is the most difficult element to degrade to quality requirements by the purification techniques, used to success- fully eliminate other elements (i.e., Fe, Al, Ca, Ti).

b Chemical removal of fluid inclusions, and subsequent degradation to 2.9 ppm Na, resulted to substantial quality improvement of quartz (a) Milky quartz vein exposure in the (Table 1). However, after a specific, Vertiskos Formation Gneiss; contamination free comminution, and a first (b) Semi-transparent quartz with minor iron staining. screening by XRF analysis of lump quartz samples, undertaken by Dorfner ANZAPLAN, the fol-

The quartz grains are deformed, subhedral to lowing results were obtained: 0.01 wt% Al2O3, anhedral, elongated and slightly oriented, with <0.005 wt% Fe2O3, <0.002 wt% TiO2, and K2O, relative dimensions of up to 8 mm along their Na2O, CaO, MgO were all <0.01 wt%. Due to longest axis and up to 4 mm in width. Vein- the fact that most elements are below the XRF quartz has suffered (a) an early episode of duc- detection limits, these quartz sources seem tile deformation (quartz 1), postdating the vein highly potential for high purity applications.

Table 1. Chemical composition of raw and beneficiated quartz samples from Northern Hellas (values in ppm)

1 2 3 4 5 6

element C* B** A*** C* B** A*** C* B** A*** C* B** A*** C* B** A*** C* B**

Al 79.4 34.0 12.0 650.0 484.0 17.0 183.0 116.0 6.0 26.7 19.6 5.2 31.0 27.2 15.3 346.0 116.0

Ca 56.8 11.0 <0.5 32.0 22.0 57.0 2.4 1.7 0.3 6.7 5.3 2.0 8.0 5.6 0.9 58.0 205.0

Fe 49.7 7.0 3.0 745.0 19.0 4.0 32.1 21.5 0.2 15.8 11.2 0.3 21.3 14.1 0.4 157.0 55.4

Na 14.8 22.0 10.0 47.0 13.0 5.0 32.0 25.8 6.6 7.6 6.6 3.4 3.3 3.2 2.4 27.0 21.8

K 11.6 5.0 2.0 12.0 7.0 1.0 64.7 45.2 0.7 12.8 7.5 0.5 8.2 6.0 0.8 70.0 41.5

Li 0.4 0.4 0.4 0.2 0.7 0.7 0.16 0.15 0.1 0.4 0.4 0.2 0.4 0.4 0.6 <0.2 0.1

*** Grade C: Raw material; ** Grade B: Standard grade; crushing, grinding, classification, water washing, magnetic separation; * Grade A: Optical grade; acid washing and calcination

Page 9 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

INDUSTRIAL APPLICATIONS OF VEIN-QUARTZ

3.2. Fluid Inclusions (30–1600 ppm), and Ca (up to 5500 ppm) are associated with zones of fluid inclusions. Excess Fluid inclusion-hosted, as well as structurally- Al is more likely due to the ablation of discrete bound (Fig. 3), trace elements were determined sub-micron clay or mica impurities, trapped in hydrothermal-metamorphosed vein-quartz along the healed micro-fractures. from N. Hellas, using Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) The anomalous levels of Fe may be due to min- as a screening technique of possible ultra pure eral impurities (possibly sulphides), trapped quartz resources. Figure 3. along micro-fractures. The laser ablation ICP- MS analysis, conducted in the present study,

(a) Dense network of sub-parallel resulted in the as- closely spaced quasi-linear to sessment of qual- curved secondary fluid inclusion trails along cross-cutting healed ity and industrial classification of vein-quartz, and the application of suitable beneficiation techniques able to remove elemental impurities (e.g., chemical removal of (b) Intragranular secondary fluid inclusion trails of healed micro fractures affect- fluid inclusions), ing the quartz matrix. and to produce ultra-pure grades.

The main objective of these determinations was Mineral processing studies were focused on to test whether the elemental “impurities”, in beneficiation of quartz tailings samples to con- terms of commercial value, recorded by bulk vert them into exploitable resources and com- chemical analysis of quartz, were due to the mercial products, as well as beneficiation tests presence of aqueous fluid inclusions or micro- on vein-quartz samples. A flow-chart including mineral impurities. Fluid inclusions have proved crushing, classification, grinding, attrition treat- to be the principal hosts of Na and Sr ment, drying and magnetic separation was de- “impurities”, and possible controllers of Mg, Ti veloped, to improve the stages of a processing and Ca abundance (Table 1). plant already in successful operation. These results confirm the estimated composi- In terms of quartz tailings beneficiation, white- tion of fracture-controlled aqueous fluid inclu- ness, iron content and mineral impurities re- sions, derived from microthermometric meas- moval, which are considered to be important for urements, which preceded LA-ICP-MS analysis. a number of construction materials and metal- The inclusions were characterised by high levels lurgical applications, were already attained by of Na (5000-2000 ppm), Sr (26 ppm) and Li (45 pilot plant testing. ppm), compared to the quartz matrix (Na 100- 600 ppm, Sr<2 ppm, Li<1 ppm). Ablation runs, Processing tests on vein-quartz samples, in- along an array or zone of inclusions, have cluded crushing, screening, magnetic separa- shown Na values of up to 6000 ppm and Sr up tion, as well as acid washing and calcination of to 37 ppm. Titanium is generally <2 ppm, and non-magnetic fractions, to achieve substantial Mg levels less than 10-20 ppm, in the quartz upgrading of final products. Several kilograms matrix. The highest levels of Ti (6-12 ppm), Mg of these samples were subjected to further puri-

Page 10 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

INDUSTRIAL APPLICATIONS OF VEIN-QUARTZ

fication processing. the required range (70-300 μm).

All mineral processing lines tested, were co- 3.3. Plasma smelting pilot-plant evaluated to further develop a working flow- construction sheet for potential beneficiation of represen- Theoretical modelling of the plasma furnace tative vein-quartz samples. conditions was carried out in order to design Laboratory and pilot-plant trials were com- the plasma technology processing line. A twin bined to define the optimum industrial scale reactor with two power supplies and graphite flow-sheet. At the same time, beneficiation lining was designed and constructed. The testing of quartz, undertaken by available, plasma furnace, to reduce heat conduction and currently operating techniques of indus- losses, consists of two graphite crucibles and trial ultra-pure quartz manufacturers, re- zirconia pieces, and a ceramic felt, and is fed duced iron content to 0.15 ppm; a fact which by alumina slag. The operating temperature has a potential value for new industrial uses. is about 2,300oC in the furnace, and about However, the problem for electronic high-tech 2,050oC at the top of the burden. Reduction applications of quartz arisen from the high of quartz (after the addition of pure iron) led Na, and not Fe, content. It is obvious that to the production of ferrosilicon and mixed low-alkali grades of quartz veins cannot be iron and silicon carbides. Work, on characteri- discovered, and beneficiation was focused on sation of the quality grade of commercial the removal of fluid inclusions. ferrosilicon, was undertaken to assess its foundry applicability. Heat Resistant Steels Further, removal testing of the <4 to 200 μm and Grey-Iron Castings were produced. fluid inclusions, and other minute mineral impurities, was undertaken by statistical tech- 3.4. Market Research niques, such as mathematical morphology The main industrial specifications, in terms of evaluation, as for example, the probability of element contamination (mainly iron, alumina, existence or not of an inclusion in a certain titanium and alkalies), fluid inclusion distribu- micro-distance from another. tion and granulation, for obtaining ultra-pure For this purpose, carefully selected and field quartz grades were established. At the same oriented quartz samples were taken, double- time a significant number of major European polished thin-sections prepared and detailed markets of quartz were identified and related fluid inclusions studies, including cluster den- to realistic applications for Hellenic quartz. sity, morphology evaluation and microphotog- Market research already started in the first raphy were carried out. year to consider the required quartz specifi- The statistical methodology, was combined cations for specific high-tech applications, with grinding systems, grain-size distribution, and to open the project’s general vision in solid-solid separation techniques, flotation, terms of industrial exploitation. It was discov- magnetic and electrostatic separation and ered that the requirements needed in semi- leaching to produce ultra-pure quartz grades. conductor and/or long-range optical fibre ap- During this process (application of statistical plications, as far as Al and Ti contents are and beneficiation techniques), three different concerned, cannot be reached with the pre- qualities of final products were obtained, sent technology, without dissolving the quartz named quartz-2, quartz-1 and ultra-pure itself, in any natural quartz mined today at quartz. The problem with these purified prod- any quantity. ucts is not the quality that is well within the For semiconductor applications the alkalies are optical glass quartz specifications, but the particularly important, with Na and Ca contents granulometry (<30 μm), which is well below of Hellenic raw quartz being somewhat high.

Page 11 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

INDUSTRIAL APPLICATIONS OF VEIN-QUARTZ

Other end-users require specifications of 4. CONCLUSIONS (Li+Na+K) <1 ppm. Significant reserves of quartz of variable On the other hand, a specific European indus- quality have been located that guarantee con- try requires less strict quality specifications of tinuity of product supply to industry over a silica flour for optical glass production, with a period of tens of years. Beneficiation testing current consumption of 600 tonnes per an- resulted in obvious quartz quality improve- num (tpa). In the framework of the project, a ment. The main techniques required for fur- number of quartz grades for various applica- ther purification, e.g., removal of fluid inclu- tions and related prices, were determined. In sions and trace element impurities, have terms of exploitation, the project objectives been identified and experimentally developed. were disseminated through contacts with in- In addition, the flow-chart for beneficiating dustrial end-users and conference presenta- and converting quartz tailings to commercial tions. products was industrially elaborated.

The mineral exploration already conducted, A market research of the variably purified and located feasible vein-quartz deposits, which upgraded quartz powders, for a number of require further investigation, mainly with re- industrial applications, has been systemati- spect to quality characterisation. The quartz cally initiated. Finally, the plasma furnace, producing industry in Hellas faces today seri- coupled by quartz fines melting, and the ous problems of lack of resources and, also, ferrosilicon and silicon metal production, has new technology possibilities for product up- been designed and constructed. grading and market expansion.

The market research and analysis undertaken, during the implementation of the Euro- pean Brite-Euram II project, identified new commercial opportunities for specific products and applications of Hellenic quartz. Looking at the European market size for high purity micronised quartz (<10 μm), a reasonable estimate for the total amount required is about 5,000 tpa. It makes a high added value product, with a cost of about 600 Euro/ton. The main areas of application are in plastics, and in paints for road markings.

The Hellenic quartz industry, when the effective R&D steps are taken, could achieve an annual production of high purity micronised quartz, in the order of 2,000-3,000 tpa. In addition to the previous products, Hellenic quartz, due to its unique whiteness, remains a competitive source for ceramic and construction applications. Of course, the achieve- ment of optical grade end-products remains a strong potential opportunity of the Hellenic quartz industry.

Page 12 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

INDUSTRIAL APPLICATIONS OF VEIN-QUARTZ

PROJECT BRE2-CT94-1026:

“NEW INDUSTRIAL APPLICATIONS FOR QUARTZ DEPOSITS INDIGENOUS TO THE COMMUNITY”

PARTNERSHIP - ROLE OF PARTNERS: I.G.M.E.:

• The Institute of Geology and Mineral Exploration SCIENTIFIC STAFF INVOLVED IN THE PROJECT (I.G.M.E.), serving as project leader, coordinated the joint research. Also, it contributed with all available • Regional Unit of Central Macedonia: mineral exploration data, and provided quartz sam- A. Theodoroudis, N. Veranis, N. Apostolou, ples for analyses and testing. P. Tsamantouridis, C. Papadopoulos, K. Katsiavalos, S. Kilias (presently at Athens University) • The Hellenic Industrial Minerals S.A. (ELVIOR), the main quartz exploitation and development company in • Division of Mineral Processing: Hellas, expanded its processing plant capacity in order Μ. Grossou, N. Kaklamanis, V. Angelatou, P. Chara- to introduce an ultra-pure quartz production line. lampidis, F. Chalkiopoulou, I. Mavrogiannis

• The Metallurgical Industrial Research and Technologi- • Division of Mineral Economic Evaluation: cal Development Centre S.A. (MIRTEC), equipped I. Drougas, V. Pefani. with pilot plasma furnace, applied the plasma technol- • Division of Geophysics: G. Skianis ogy to produce silicon metal and ferro-silicon with low impurities content. • Division of Mineralogy and Petrography: V. Perdikatsis (presently at the Τechnical University of Tetronics R&D Company Ltd., a high-tech manufac- • Crete), S. Karantassi, G. Economou turing company, having extensive experience in pilot plasma furnace test work in the extractive metallurgy, designed and developed MIRTEC's plasma facilities.

• Universite Libre De Bruxelles focused mainly on the technical characterisation of quartz to consider its beneficial ability to produce ultra-pure qualities.

• Fundiciones Del Estanda S.A., a foundry industry, produced special ferrosilicon steels with low impurities content to meet the growing demands of the international steel market.

• UKAB, an ultra-pure quartz company, contributed in optimising the beneficiation techniques of Hellenic quartz to produce ultra-pure qualities and established potential commercial interest.

Page 13 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

MINERALOGICAL- PETROGRAPHICAL LABORATORIES

DIVISION OF MINERALOGY & PETROGRAPHY ([email protected])

The Division of Mineralogy and Petrography in terms of its multiple activities on mineralogical and petrological studies of geological, mining, environmental, hydrogeological and other research, is ac- tively involved in the research of industrial minerals and rocks, i.e., Zeolites, Quartz, Clays, Garnets, Marbles, etc. Figure 1b. SEM Photographs.

Figure 1a. Scanning Electron Microscope (SEM).

More specifically, it is carrying out specialised laboratory determinations and analyses, with state-of-the-art high technology methods, on samples from all over Hellas, as well as samples of imported materials and products.

In the Division, there are also specialised sample preparation laboratories for making thin and polished thin sections etc. Figure 2. Raman.

The analytical techniques used are: • Light microscopy • Scanning Electron Microscopy (Fig. 1) • X-Ray Diffraction • Micro-Raman Spectroscopy (both portable and desk instrument) (Fig. 2) • Differential Thermal Analysis

Page 14 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

APPLIED MINERALOGY FOR THE EFFICIENT EXPLOITATION OF WASTED MAGNESITE RUN- OF- MINE FINES

Fotini Chalkiopoulou & Martha Grossou-Valta Mineral Processing Engineers ([email protected]) I.G.M.E., Division of Mineral Processing Stavroula Karantassi Mineralogist ([email protected]) I.G.M.E., Division of Mineralogy & Petrography

The MAGFINES Abstract Project Applied mineralogy is a key tool for the process engineer, from the very early stage of field Processing of research up to the final of decision making for processing of a mineral raw material. This was Magnesite Run-Of- obvious in the case of developing process routes, appropriate for the recovery of magnesite Run-Of-Mine (R.O.M.) fines that were stockpiled for many years as wastes, stemming from Mine Fines sorting in N. Hellas, amounting to 30% of excavated ore. Extensive mineralogical work was carried out throughout the whole project, comprising mainly of Optical Microscopy, Differential Mineralogy— Thermal Analysis, X-Ray diffraction and Electron Probe Analysis. Detailed work was done at the Petrography of beginning of the project in order to identify the different mineral constituents of the material Magnesite under investigation. Mineralogy supported the evaluation/selection of processing methods/ techniques, and design of a generic flow diagram. Alternative magnetic separation and heavy Ore Model of media separation techniques were tested. The innovation was the exclusive development of a Magnesite for new Reticon Camera Sorter for project needs. Non-magnetic drums were also used in an innovative way for ‘screening’ the material. Simulation tools were also used for optimisation of the Simulation process flow-sheet, based on an ore model, developed specifically for the project. In conclusion, mineralogy, not only contributed greatly to the development of a process methodology for the beneficiation of magnesite fines, but was a key technique of the whole project.

Περίληψη

Η ΧΡΗΣΗ ΤΗΣ ΕΦΑΡΜΟΣΜΕΝΗΣ ΟΡΥΚΤΟΛΟΓΙΚΗΣ EΡΕΥΝΑΣ ΓΙΑ ΤΗΝ ΑΠΟΤΕΛΕΣΜΑΤΙΚΗ ΑΞΙΟΠΟΙΗΣΗ ΨΙΛΟΜΕΡΟΥΣ ΜΠΑΖΟΜΕΤΑΛΛΕΥΜΑΤΟΣ ΜΑΓΝΗΣΙΤΗ: Η εφαρμοσμένη Ορυκτολο- γική–Πετρογραφική Έρευνα είναι σημαντικό εργαλείο για το μηχανικό εμπλουτισμού από τα πρωταρχικά στάδια μελέτης για την αξιοποίηση μιας Ορυκτής Πρώτης Ύλης ως και το τελικό στά- διο της λήψης αποφάσεων για τη μεθοδολογία εμπλουτισμού. Εδώ αναφέρεται το παράδειγμα του έργου MAGFINES που είχε στόχο την ανάκτηση του μαγνησίτη από το λεπτομερές, <12 mm, μπαζομετάλλευμα της εκμετάλλευσης του κοιτάσματος στη Γερακινή στη Β. Ελλάδα και συνιστά το 30% κατά βάρος, του συνολικά εξορυσσόμενου πετρώματος. Στο πλαίσιο του έργου πραγμα- τοποιήθηκε λεπτομερής ορυκτολογική/πετρογραφική διερεύνηση μέσω Οπτικής Μικροσκοπίας, Διαφορικής Θερμικής Ανάλυσης, Περιθλασιμετρίας με ακτίνες-X και Μικροανάλυσης και αφενός πρόσφερε αναλυτικές πληροφορίες για το υπό μελέτη υλικό, αφετέρου υποστήριξε σημαντικά τις φάσεις αξιολόγησης και επιλογής των μεθόδων/τεχνικών για τον εμπλουτισμό του μπαζομεταλ- λεύματος. Στα εναλλακτικά διαγράμματα ροής που εξετάστηκαν, εφαρμόστηκαν μαγνητικός δια- χωρισμός και βαρέα διάμεσα ενώ ένας πρωτοποριακός οπτικός διαχωριστής (Reticon Camera Sorter) αναπτύχθηκε στο πλαίσιο του έργου, ειδικά για τις ανάγκες του υπό μελέτη υλικού. Επι- πρόσθετα, μη-μαγνητικά τύμπανα χρησιμοποιήθηκαν κατά ένα καινοτόμο τρόπο για το «κοσκίνισμα» του υλικού. Για την αριστοποίηση του κυκλώματος επεξεργασίας χρησιμοποιήθηκε το εργαλείο προσομοίωσης USIM PAC, η εφαρμογή του οποίου βασίστηκε αποκλειστικά σε ορυ- κτολογικό μοντέλο που αναπτύχθηκε και προσαρμόστηκε στο συγκεκριμένο υλικό. Συμπερασμα- τικά αναφέρεται ότι η ορυκτολογία όχι μόνο συνέβαλε καθοριστικά στην ανάπτυξη της μεθοδο- λογίας για τον εμπλουτισμό του ψιλομερούς μπαζομεταλλεύματος της Γερακινής, αλλά αποτέλε- σε κρίσιμο τμήμα της συνολικής μελέτης και του έργου MAGFINES.

Page 15 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

EXPLOITATION OF MAGNESITE RUN-OF-MINE FINES

1. INTRODUCTION occurrence is common to all samples and size fractions studied, and their percentage propor- The case examined in this paper concerns the tions show only slight differences from sample Brite EuRam project “New Process Routes for to sample and from size fraction to size fraction. the Recovery of Magnesite Run-of–Mine Fines (BRE2-CT92-0388)”, with the acronym MAGFI- Table 1. Mineral constituents of R.O.M. fines NES, co-ordinated by Grecian Magnesite S.A. Mineral Formula with partners the Institute of Geology & Mineral Magnesite Exploration, Hellas, and Control International MgCO3

S.A., France. The aim of the project was to de- Olivine (SiO4)(Fe,Mg)2

velop a new procedure for the potential exploi- Enstatite (Si2O6)(Mg,Fe)2 tation of industrial mineral fines (<12 mm), be- Chromite (FeII,Mg)(Cr, Al, FeIII)2O4 ing the waste from a previous treatment. The Serpentine (Si2O5)Mg3(OH)4 focus was on Hellenic magnesite Run-Of-Mine Magnetite (R.O.M.) fines in order to increase the magne- Fe3O4 Tremolite site production capacity at a low cost, to reduce Ca2Mg[(OH)2Si8O22)]

the waste disposal area requirements, and thus Phyllosilicates KMg3[(OH),F)2AlSi3O10

to slow down the depletion of natural mineral Chlorite Mg5(Al,Fe)(OH)8(Al,Si)4O4 wealth. Major and complex problems were ad- Talc Mg3(OH)2(SiO5)2 dressed during project implementation that con- Dolomite (Mg,Ca)CO3 cerned the nature and physical properties of Calcite materials under investigation. The answers to CaCO3 Quartz these problems were crucial for process selec- SiO2 (chalcedony, opal) tion, and the efficiency of the separate meth- Iron Hydroxides FeO(OH) (goethite) ods/techniques applied. Magnesite (Fig.1) occurs in pure or composite grains, is cryptocrystalline and found in two 2. IDENTITY OF THE MATERIAL grain sizes. The finer grains (a-Mg) are <5 μm, 2.1. Methods while the coarser ones range from 5 to 10 μm (β-Mg). The cryptocrystalline texture of magne- Extensive work was carried out at the beginning site is, in general, a favourable factor for its 2,3,7 of the project on samples representing vari- molecular purity. ous stockpiled materials and current (at that time) R.O.M. fines. The laboratory methods employed were: (a) Optical (polarising light and stereoscopic microscope), (b) X-ray diffracto- metry (SIEMENS Diffractometer), (c) Differen- tial Thermal Analysis (METTLER thermoana- lyser), and (d) Electron probe analysis (JEOL microanalyser). A SWIFT Point Counter was also used; quite a few thin sections were stained and microphotography was applied.

2.2. Mineralogical Composition

The mineralogical studies showed that the ma-

terial under investigation is of variable mineral- Figure 1. Pure cryptocrystalline magnesite (Mg) aggregate ogy (Table 1), and the main minerals are mag- (Transmitted light, +Nicols, x166). nesite, serpentine and quartz. Their mode of Serpentine representing serpentinite is the prin-

Page 16 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

EXPLOITATION OF MAGNESITE RUN-OF-MINE FINES

cipal mineral of the petrological environment of It is expected that, where there is strong adhe- magnesite, and is the most widespread phase in sion between magnesite and silicates, especially gangue material. It occurs in high percentage in the case of cryptocrystalline (chalcedony) and proportions in all samples, regardless of grain amorphous (opal) varieties, the effort to sepa- size, and occurs in foliated (antigorite-lizardite), rate and remove them will not give satisfactory fibrous (chrysotile) and cryprocrystalline results. Part of the quartzitic material contained (serpophyte) forms (Fig. 2). The high iron hy- in the fines is rich in iron hydroxides, and can droxide content in several serpentine grains in be removed by magnetic separation. iron hydroxides facilitates their removal by magnetic separation. 2.3. Impurities in Magnesite Microscopy showed that part of the magnesite grains are composite. This feature is observed in all samples/fractions, and is associated with the genesis of magnesite. It is also an important factor for the selection of processing method(s), and affects the qualitative and quantitative character of the final product.

The nature, form and percentage proportions of these admixtures, as well as their mode of association with magnesite, are so variable that their complete separation is apparently very difficult. It is estimated that, application of some processing procedures will result, either in mag- Figure 2. Composite fragments of magnesite (Mg), talc (Tc), serpentine (Srp), pyroxene (Py) in various combinations nesite "losses" (removal of composite grains (Transmitted light, +Nicols, x66). with gangue), or in low quality final products Quartz–Chalcedony–Opal: Grains of mostly (due to presence of composite grains). These quartz, but also chalcedony and rarely opal, oc- impurities create various qualitative and quanti- cur in all size fractions of the samples studied. tative combinations in the particular magnesite The close association of magnesite-silicates, as grains, resulting in the so-called multi- observed partly in some grains (Fig. 3), makes composite fragments. It should also be made their complete separation difficult, in addition to clear that the quantitative participation of mag- the lack of magnetic susceptibility of both mate- nesite in this class of material is variable, and is rials and their similar colours. estimated to exceed 50% as a rule. It is finally mentioned that these composite magnesite grains follow the downward trend, observed for mono-mineral grains from coarser to finer size fractions in the studied samples. Impurities in magnesite consist, almost exclusively, of iron hydroxides in the finer fractions (<0.053 mm).

3. CONTRIBUTION OF MINERALOGY DURING PROCESSING

3.1. F.I.S. Test-Work

The objective of the processing test work was to Figure 3. Composite magnesite (Mg) and quartz (Q) grains decide on the selection of the most appropriate in various proportions (Transmitted light, +Nicols, x42).

Page 17 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

EXPLOITATION OF MAGNESITE RUN-OF-MINE FINES

combination of methods/techniques for efficient processing methods, gravimetric and magnetic and economic production of commercial grades separation, were decided to be examined in the of raw magnesite, namely products with a mini- laboratory, parallel to the optical separation

mum MgCO3 content higher than 80%. For this tests. For the gravimetric separation test work, purpose, a series of laboratory and pilot scale a dense media WEDAG Cyclone, and a dense tests were performed. Orientation tests were media WEMCO Cone were used. For the mag- initially carried out with a Frantz Isodynamic netic separation test work, a cross belt magnet Separator (F.I.S.). A number of samples were (dry), an ERIEZ WHIMS electromagnet (wet), magnetically separated with F.I.S. in order to and an ERIEZ Rare Earth Roll magnet (dry) evaluate the relative susceptibility of the vari- were employed.2,3,7 ous grains of the different minerals.4,5 The com- Considerable mineralogical research4,5 was exe- position of magnetic and non magnetic products cuted also, during this stage of laboratory re- was studied in detail by Optical Methods. These search, in order to evaluate the results obtained data and information were very important for from the processing test work, and to acquire the development of the ore model that was supplementary information on the physical used for process simulation. characteristics of the 0-12mm material. From 3.3. Mineralogical Examinations During the investigation applied, valuable information Laboratory Process Testing was produced, concerning the quality of non- magnetic products, middlings, sinks and floats. The overall research was oriented towards the Moreover, the material’s behaviour during siev- R.O.M. wastes’ processing that could be easily ing and processing was adequately explained incorporated in the existing mill of Grecian Mag- with the assistance of mineralogy. nesite (GM) and methods such as flotation was not considered at all, since optical separation and heavy media treatment were the proce- 4. DEVELOPMENT OF THE ORE MODEL dures already installed. The lower limit for proc- Model-based, steady-state optimisation was essing had been so far the 12 mm, which ex- used as the most powerful approach to maxi- plains the stockpiling of the <12 mm ROM ma- mise the efficiency at the design stage. An ore terial. GM was the first company to attempt the model was developed to represent processed design of a sorter for the treatment of 5-12 mm material. Mathematical models were selected, material. The development of this new Sorter adapted or developed, for several unit opera- was achieved within the project. This machine is tions, which were considered in the compilation using Reticon Camera technology rather than of the final flow-sheet. Model parameters were lasers, as in existing models that are processing determined from extensive laboratory, pilot >12 mm materials.1 Further to testing on the plant and industrial testing. Lastly, the process specific sorter, there was work on: (a) Pilot flow-sheet was defined, simulated and opti- scale scrubbing and sieving, (b) Cross belt mag- mised. The USIM PAC8 software, developed by netic separation, (c) Wet high intensity mag- CI.S.A., was used for the simulation. It was, netic separation, (d) Rare-earth magnetic sepa- therefore, very important to develop a reliable ration, (e) Magnetic drums/rolls for fines sepa- Ore Model that could be incorporated into the ration, (f) Non-magnetic drums for fines sepa- software and, thus, help to predict the efficiency ration, (g) Laboratory and pilot heavy media of the different processes/methods during simu- cone/cyclone, and (h) pilot and industrial scale lation. To achieve this, a number of assump- testing on TRIFLO heavy media separation. tions were adopted that allowed the conversion After taking into consideration the mineralogical of assays into mineral phases comprising vari- and physical characteristics of the different min- ous combinations of the minerals identified. erals occurring in the R.O.M. fines, two main These assumptions were based on detailed ex-

Page 18 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

EXPLOITATION OF MAGNESITE RUN-OF-MINE FINES

perimental studies, and mainly the accurate (i.e., silica) that may equally accompany con- mineralogical examinations and observations. centrates or tailings. Taking into consideration, They are summarised below:7 material composition, and distribution of miner- • Total CaO contained in the material, is as- als over the different size fractions, it became sumed to be associated with CO2, forming obvious that no method could alone be effective CaCO3. It is considered that 80% of total for processing. There should be an appropriate CaCO3 estimated, occurs in the form of dolomite. combination of methods (i.e., magnetic separation, gravimetric separation). Moreover, the • The remaining amount of CO occurs in the 2 overall research was applied and focused to the form of magnesite (MgCO3). ‘Pure’ magnesite development of routes that could be incorpo- grains are considered to contain 95% MgCO3 and 2.5% SiO2. A typical grade of composite rated in the existing GM company’s mill. Con- magnesite grains is 75% MgCO3, and 15% ventional equipment, such as drums may be SiO2. A proportion of 20% of total MgCO3 is used in an innovative way for the simultaneous assumed to occur in the form of composite removal of fines and gangue, since traditional magnesite grains. screening of the specific 0-12 mm material is • Typical grade of ‘silica’ grains is 20% MgCO3 problematic. and 70% SiO2. A proportion of 10% of total SiO2 is in the form of ‘silica’ grains, and In conclusion, the effective collaboration of the • Typical grade of serpentine grains is 7% mineralogist and process engineer may not only MgCO3, and 50% SiO2. facilitate scientific research for a specific material’s beneficiation, but it may also produce in- 5. REMARKS AND CONCLUSIONS novative ideas, and result in a successful completion of a project. The significant role of mineralogy during mineral processing was stressed in the aforemen- REFERENCES tioned paragraphs. More specifically, mineralogy provided a fundamental and significant key in- 1. Arvidson, B. & Reynolds, M, 1995. New Photometric Ore Sorter for Conventional and Difficult Applications. Proc- put for the MAGFINES project in order: essing for Profit. 1 International Minerals Processing • To acquire a clear and accurate description of Conference, Amsterdam, 26-27. the materials under investigation as per their 2. Brite-Euram II, 1993a. New Process Routes for the Re- composition, their liberation characteristics, covery of Magnesite Run-Of-Mine Fines. 1st Progress Report, November 1st/1992 - April 30th/1993. June non-desirable impurities in the valuable min- 1993, 1-8. erals, as well as peculiarities of grains. 3. Brite-EuRam II, 1993b. New Process Routes for the Re- • To predict the materials’ behaviour against covery of Magnesite Run-Of-Mine Fines. 1st Annual Pro- gress Report, November 1993, Chapter 2, 27-39. the available processing methods/techniques, based on the above information, thus pre- 4. Brite-EuRam II, 1994a. New Process Routes for the Re- covery of Magnesite Run-Of-Mine Fines. 3rd Progress selecting the appropriate ones and avoiding Report, Chapter 3, 6-8. unnecessary efforts. 5. Brite-EuRam II, 1994b. New Process Routes for the Re- • To evaluate the beneficiation results, and ap- covery of Magnesite Run-Of-Mine Fines. 2nd Annual Pro- ply alternatives, as well as to develop innova- gress Report, December 1994, chapter 4, 17-20. tive routes and to conclude with the compila- 6. Brite-EuRam II, 1995. New Process Routes for the Recov- tion of a generic flow diagram. ery of Magnesite Run-Of-Mine Fines. Final Technical Re- port, December 1995, 26-34. • To ‘construct’ a tailored ore model appropri- 7. Brite-EuRam II, 1995. New Process Routes for the Recov- ate for simulation purposes. ery of Magnesite Run-Of-Mine Fines. Final Technical Re- port, December 1995, 83-91. Thus, with the help of mineralogy, it was appar- 8. Broussaud, A., Guillaneau, J.-C., Guyot, O., Pastol, J.-F. ent from the project start that no high magne- & Villeneuve, J., 1991. Methods and Algorithms to Im- site grades could be expected from the treat- prove the Usefulness and Realism of Mineral Processing Plant Simulators. Proceedings of the XVII International ment of this R.O.M., since there are many com- Mineral Processing Congress. Dresden, Germany. Sep- posite magnesite grains with such impurities tember 23-28, 229-246.

Page 19 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

«LITHOS» THE ACCREDITED ORNAMENTAL STONE QUALITY CONTROL LABORATORY OF THE I.G.M.E. ([email protected])

LITHOS Laboratory was established in 1999 to offer services to the Ornamental Stones Sector, partici- pating also in various joint research projects. The Laboratory is accredited by the “Hellenic Accredita- tion System” (“E.SY.D.”). The current “Accreditation Certificate No. 70 (2)” complies with ELOT EN ISO/ IEC 17025:2005.

LITHOS is well equipped with certified testing ma- chines and apparatuses for carrying out high quality test work, according to the European (EN) and/or other international Standards. For maintaining reli- ability in this process, LITHOS participates in Round Robin Tests together with other relevant European laboratories.

The Laboratory’s “Scope of Accreditation” includes Although the Laboratory’s solely EN Standards “Test Methods”, following the activities are mainly re- current practice in EU Member States. lated with natural ornamental stones, where the Some EN Standards determine “Requirements” on existing equipment per- the final products of various ornamental stones mits, other types of rele- for the purpose of assigning the relevant CE vant materials (i.e., marking, in relation to their potential application. aggregate concrete ma- For certain product types sonry units, concrete pav- and applications, the CE ing flags, agglomerated marking is gradually becom- stones, etc.) can also be ing obligatory in Hellas. Thus, without the CE tested. marking, these products will not be able to face competition in the European and International markets. For this purpose, LITHOS is in the process of obtaining the appropriate “Notification” to perform the necessary test work for the needs of any producer. Meanwhile, LITHOS, as the only accredited Hellenic Laboratory performing the whole range of these tests, can provide, upon request, the relevant services to any interested party.

The objective of LITHOS is to offer high quality services for the determination of physical

mechanical properties of ornamental stones in order to set up their identity in the

process of granting final stone products with the obligatory CE marking.

Page 20 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

HELLENIC MARBLE THROUGH THE AGES: AN OVERVIEW OF THE MARBLE PRODUCING AREAS AND THE STONE SECTOR OF TODAY

Dr. Kostas Laskaridis Geologist ([email protected]) I.G.M.E., Division of Economic Geology, LITHOS laboratory

Hellenic Stone Abstract Sector This article gives an overview of the Hellenic marble sector, and provides information on its Marble Sector historical development, and its geological background. Reference is made on the major Hellenic marble-producing areas. The great wealth of Hellas, with respect to high quality marble depos- Marble Producing its, mainly white types, in combination with a very long tradition in the art of marble, the roots Areas of which go back to ancient times, have much contributed to the development of the modern and dynamic Hellenic marble industry, which is rated among the top world producers of decora- Marble Imports- tive natural stones, both in size of production and exports. Exports Περίληψη

ΑΝΑΣΚΟΠΗΣΗ ΤΩΝ ΜΑΡΜΑΡΟΦΟΡΩΝ ΠΕΡΙΟΧΩΝ ΚΑΙ ΣΗΜΕΡΙΝΗ ΚΑΤΑΣΤΑΣΗ ΤΟΥ ΚΛΑΔΟΥ ΤΩΝ ΔΙΑΚΟΣΜΗΤΙΚΩΝ ΠΕΤΡΩΜΑΤΩΝ ΣΤΗΝ ΕΛΛΑΔΑ: Το άρθρο κάνει σύντομη ανασκόπηση του κλά- δου του μαρμάρου στην Ελλάδα και παρέχει πληροφορίες για την ιστορική εξέλιξή του, καθώς και για τις κυριότερες περιοχές εξόρυξης κατά την αρχαιότητα και σήμερα. Τα υψηλής ποιότητας κοιτάσματα μαρμάρου του Ελλαδικού χώρου, κυρίως τα λευκού τύπου, σε συνδυασμό με τη μα- κρά παράδοση της Ελλάδας στην τέχνη του μαρμάρου από την αρχαιότητα, έχουν συνεισφέρει στην ανάπτυξη μιας σύγχρονης και δυναμικής Ελληνικής μαρμαροβιομηχανίας, η οποία κατατάσ- σεται ανάμεσα στους κορυφαίους παγκόσμιους παραγωγούς φυσικών διακοσμητικών πετρωμά- των, τόσο για την παραγωγή, όσο και για τις εξαγωγές.

1. INTRODUCTION

In Ancient Hellas the use of marble lithic era (about 5,000 B.C.) with had been very wide. Marble and marble female idols, whilst later the stone were the materials that deeply series of the famous Cycladic idols touched the human sensitivity and followed. The first monuments of driven humans to the world of aes- Hellenic sculpture (marble was used thetics and symmetry. in combination with porous- material) appeared as early as 630 Marble has been used in Hellas for B.C. Representative examples of the construction of sacred buildings, such monuments were the temple of since early recorded times. The an- Zeus at Olympia, as well as the tem- cient Hellenes were the first, among ple of Apollo at Delphi, with marble many ancient civilisations, to notice from the island of Paros in the fa- the unique properties of this re- çade and porous-sandstone for the markable durable stone, which re- remaining part of the construction. mains so beautiful and can be easily The peak of the Hellenic Classical shaped according to their needs. Period is represented by such out- Marble quarrying in Hellas started standing structures as the Athens several centuries ago. The earlier Acropolis with the Parthenon and statues go back to the Middle Neo- Erecthion, the Aphrodite of Milos,

Page 21 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

HELLENIC MARBLE THROUGH THE AGES

the Hermes of Praxitelis, etc. ducing countries in the World. It provides the global market with rare varieties of marble that The history of the Modern Hellenic marble in- can scarcely be found elsewhere, and which dustry started in the 1960's, when building ac- have greatly contributed to the history of civili- tivities and standards of living rose remarkably. sation. The number of marble quarries has been con- tinuously increasing since the 1960's. Marble quarrying in Hellas started from ancient times, going back to at least 5,000 B.C. (Middle Neolithic Era). During the 6th, and mainly the 5th 2. TERMINOLOGY - GEOLOGY century, intensive quarrying is reported in the The commercial use of the term “marble” – following exploitation centres: Penteli and Aghia “μάρμαρο” (marmaro) in the Hellene language - Marina of Attica area, the islands of Naxos, does not only include the metamorphic lime- Paros (the famous marble of Paros, better stone formations, but also any ornamental known as ‘lychnitis’ has been quarried since an- stone that can be cut to standard dimensions, tiquity) and Thassos (white marble quarried at can be cleaned to a mirror finish – polished, and the Capes of Alyki, Fanari and Vathi), and Phi- finally used in the decorative marble art. In lippi, near to Kavala, for white marble. Tinos general, the name “marble” is given to a variety Island, Styra and Karystos on Evia Island of rock types, such as metamorphic rocks, e.g., (famous in ancient times for the marble quar- crystalline limestone, and/or sedimentary rocks, ried by the name ‘Karystia lithos’ or ‘Cipollino of for instance, calcareous alabasters, etc. Cur- Karystos’), Hassabali near to Larissa and Kro- rently, although there is still a habit of calling kees in Peloponissos (famous for the greenish ornamental stones by their traditional names ‘krokeatis lithos’) for green marble. Eretria on (some of them given in antiquity), norms are the island of Evia for red marble and finally Sky- being developed (e.g., by CEN TC 246) to char- ros Island (‘marble of Skyros’, this name was acterise a rock by its traditional name, by its given to the conglomerate that was quarried in petrographical name and its place of origin ancient times) for multi-coloured marble. (“Denomination Criteria”– EN 12440). In the early 20th century, extensive exploitation The geological history of Hellas has been influ- has started and marble has been exported in enced by conditions of intense orogenesis, mag- Western Europe. Thus, the Hellenic marble be- matism and metamorphism that led to the de- came well known abroad. The intensive exploi- velopment of extensive deposits of ornamental tation of Hellenic marble starts in the 1960’s, as stones. Today, in Hellas the following ornamen- a result of the sudden development of construc- tal stones are widely used: tion in urban centres, and the higher standard of living. Marble became a widely consumed in- • Metamorphic rocks: Calcitic marble, dolomitic dustrial product, with increasing demand, par- marble, cipolline marble, gneiss and ophical- cite. ticularly in large constructions and specific uses. To meet these demands, further increase of • Sedimentary rocks: Limestone, travertine, breccia, onyx and alabaster. marble production was necessary, and it was achieved through the exploitation of new re- • Magmatic rocks: Granite and granodiorite. serves all over the country. In parallel, new modern cutting and processing units were de- 3. HELLENIC MARBLE PRODUCING veloped. AREAS (DEPOSITS) IN ANCIENT A brief description, and the current status of the AND MODERN TIMES major Hellenic marble producing areas, is given Hellas is extremely privileged with regard to below (Figs. 1 & 2). marble deposits, and is one of the major pro-

Page 22 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

HELLENIC MARBLE THROUGH THE AGES

(Koumaria, Veria and Tranovaltos, Zoodochos Pigi, Zidani, Roditis and Servia of Kozani).

3.3. Ioannina Region (Epiros)

In the area of Ioannina, the characteristic ‘beige’ limestone, called ‘gianniotico’, is quarried. It used to be the most utilised ornamental stone in the Hellenic construction industry, due to its nice colour and low price.

3.4. Larissa & Volos Regions (Thessaly)

The area of Larissa and Volos offers a great variety of white, whitish, pink, and coloured marble. The marble of Tis- saion Mountain (pink of Figure 1. Main Hellenic marble producing areas. Lafkos), at the southern end of Magnesia penin- 3.1. Drama, Kavala and Thassos Regions sula, is of great economic value. Intensive ex- (Eastern Macedonia) ploitation took place during ancient times. In the marble-bearing beds of Kavala and 3.5. Penteli (Attiki Region) Drama units (Rhodope Massif), the metamorphic carbonate rocks (calcitic and dolomitic) are This area produced the world famous Pentelikon widely distributed. white marble, by the names ‘Bianco di Pendeli’ or ‘Marmo Greco Fino’. Penteli marble quarrying The most important marble producing locations started in ancient times, and continued system- in this area are: Thassos Island (white of atically up to 1976, when the quarrying activity Saliara Thassos, white of Limenas Thassos in the south-western slopes of Penteli has ‘Prinos’, Crystallina of Thassos), Volakas (White ceased, due to measures taken for environ- of Volakas, the most exported Hellenic marble mental protection. The white marble quarrying to China), Stenopos (Semi-white of Kavala), has been restricted ever since in the northern Nestos, Limnia, Nikissiani, Piges, Elaphohorio, part of the Penteli Mountain. In the areas of Dysvato, Vathilakos, and Palia Kavala. Dionyssos and Aghia Marina about 10,000 to 3 3.2. Kozani and Veria Regions (Western 15,000 m /year are produced. Today, system- Macedonia) atic exploitation (mainly underground) of the Dionyssos marble continues in the area of Pen- From this area white and white-whitish and col- teli. oured marble of superior quality is quarried

Page 23 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

HELLENIC MARBLE THROUGH THE AGES

3.6. Levadia and Domvrena (Sterea Hel- sills) and exterior decorations (window ledges, las) door stones, copings, profiles), and furnishings.

The areas of Levadia and Domvrena, offer a wide variety of pink-white, whitish, black and 5. STONE SECTOR IN HELLAS - coloured marble. The most important marble CURRENT STATUS types in the area are: Whitish of Helikona, Pink of Levadia, and the Black of Levadia. The modern and dynamic Hellenic marble industry is rated among the top world producers of 3.7. Other Regions decorative natural stones, with respect to both size of production and exports. Now-a-days, Apart from the above mentioned important pro- quarrying companies are scattered all over Hel- duction and processing centres, it is worth not- las, since there are marble deposits almost in ing the marble exploitation in many other areas, the whole territory (Fig. 1). such as the Aegean islands: Naxos (White-Semi white Crystallina of Naxos), Tinos (Green of Ti- The number of companies engaged in the mar- nos), Paros (Semi-white), Evia (Green of Styra, ble sector is estimated to be about 4,000 (6.7% Black of Aliveri, multi coloured marble of Sky- of the Dimension Stones Sector in Europe), and ros, etc.), Crete and Argolis regions includes small, medium-sized, and also several (Peloponissos), where mainly beige marble large units that they have made important in- types (Karnazeika, Didyma, Ligourio, etc.) are vestments, and rank among the best industrial quarried. units in Europe. The Hellenic marble sector em- ploys more than 60,000 people (12% of the 3 6 European employment sector); a large number 17 have a high level of specialty in the fields of quarrying, processing and installation of marble. 21 The Hellenic marble companies are mainly en- 79 gaged in one of the following fields: Quarrying, Cutting and/or processing, Manufacture of art works, Ecclesiastical elements and Memorials, 26 Trade of marble blocks, and a variety of products for the home and foreign markets, Installa-

6 tion and applications. However, there are sev- 9 eral companies that have achieved vertical or- 22 14 ganisation. Eastern Macedonia Central Macedonia Western Macedonia Epirus The marble quarry production has impressively Thessalia Sterea Hellas increased during the last few years. The total Peloponnese Kyklades islands Crete Other regions quarried production has risen sharply. In year 1966, the quarried production of marble blocks Figure 2. Number of quarries per region (Data 2004). was 141,000 tonnes. In 2002 and 2003, the annual production was ca. 2,100,000 tonnes, or 4. MAIN APPLICATIONS OF STONES 3% of the world ornamental stone production. In 2004, the annual production decreased to Today, the most common applications of dimen- 1,400,000 tonnes or 1.8% of the world orna- sional stones are facings and floorings, both in- mental stone production (Fig. 3). ternal and external, gravestones and sacred art, According to 1996 data, collected from Statisti- structural applications, special works, such as cal Institutes of E.U. States, Hellas occupies the refurbishing, restoration and roofing, staircases, fifth position in the world quarry production and interior (skirting boards, door stones, window

Page 24 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

HELLENIC MARBLE THROUGH THE AGES

export of ornamental stones, after Italy, China, 0,45 Quantity in tonnes Spain and India. However, due to strong com- 0,40

Millions Value in '000 € petition, Hellas is gradually loosing this position. 0,35

In 2003, Hellas occupied the ninth, and in 2004 0,30 the eleventh position among the top ornamental 0,25 stone producing countries in the World, after 0,20 China, India, Italy, Spain, Iran, Turkey, Brazil, Egypt, Portugal and U.S.A. 0,15 0,10 0,8 0,05 0,7

Millions 0,00 0,6 1998 1999 2000 2001 2002 2003 2004 2005 Figure 5. 0,5 Evolution of import of ornamental stones in Hellas.

0,4 Imports value (both of processed and unproc- 0,3 essed marble, granite, etc.) is 65 million € for

0,2 2005, marking an increase of about 23.2% compared to the 2002 value (41.4 million €), 0,1 and an increase of around 208% compared to 0 the 2001 value (31.2 million €). Importing ac- 1966 1985 1992 1994 1996 1998 2000 2002 2004 tivity has increased from 74,757 tonnes in 1998 Figure 3. The annual marble quarry production to 404,283 tonnes in 2005 (Fig. 5). in Hellas from 1966 to 2004 (Production in m3). The first 10 import-markets in 2005 occupy a Exporting activity has also decreased, with total share of 92.7% in quantity of the total imports, unprocessed and processed ornamental stones with Turkey having by far the largest share of exported amounting to around 377,840 tonnes Hellenic imports. in 2002, 414,000 tonnes in 2003, 387,000 ton- The main import markets for ornamental stones nes in 2004, and 361,000 tonnes in 2005, from in 2004, according to quantity, were Turkey, 206,770 tonnes in 1991 (Fig. 4). FYROM, Albania, Bulgaria, Morocco, s 0,45 Egypt, China, Syrian, Italy, and In- 0,40

Million dia. 0,35 The main import markets for orna- 0,30 mental stones in 2005, according 0,25 quantity, were Turkey, Albania, FY- 0,20 ROM, Bulgaria, Egypt, Morocco, 0,15 Syrian, China, India, and Italy. 0,10 0,05 The marble sector, as it is export 0,00 oriented, constitutes one of the few 1980 1983 1986 1989 1992 1995 1998 2001 2004 sectors in the Hellenic economy, which is in a position to compete Figure 4. Export of unprocessed and processed Hellenic marble (in tonnes). in the international market. Total exports value is of €105,197,000 The problems with the environmental legisla- (both of processed (66.9%), and of unproc- tion, and the growing bureaucracy for new essed marble (blocks and slabs 33.1%) for quarrying licenses, have led the marble sector 2005, marking a decrease of around 16%, com- companies to increase imports of raw material. pared to the 2001 value (€125,115,000), and a

Page 25 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

HELLENIC MARBLE THROUGH THE AGES

decrease of around 14%, compared to the 2004 published in 2006 the fourth edition of the Hel- value. But, when compared to the 1991 value lenic Marble Directory. (€57,872,000) there is an increase of 181.7%. The I.G.M.E. is supporting the Hellenic marble The first 10 export-markets occupy a share of sector by conducting research for new marble 71.6% in value of total exports, with U.S.A. deposits, using new methods and by introducing having by far the largest share of Hellenic ex- quality control in the Hellenic marble products ports. (LITHOS laboratory). The I.G.M.E. can provide information, advice and support to anyone in- The main markets for Hellenic marble in 2002, terested in the Hellenic marble sector. according to total value, were U.S.A., China, Spain, Cyprus, Hong-Kong, Germany, Japan Saudi Arabia, Italy, and Brazil. The first 10 ex- BIBLIOGRAPHY port markets in 2002 occupy a share of 55.88% in quantity of total exports, with China having Founti, M., 2004. Stone for construction and architec- ture - From extraction to the final Product. OSNET by far the largest share of Hellenic exports. The Editions, Volume 10, Technology Transfer Sector, main markets for Hellenic marbles in 2002, ac- June 2004, 164 pp. cording to quantity, were China, Spain, Saudi Giannaros, G., 1999. Foundation of Economic and Arabia, Cyprus, U.S.A., Hong-Kong, Italy, Ger- Industrial Research (IOBE), Greek marble sectors study, 18 pp. In: http://www.osme.8m.com/ many, Japan, and Brazil. kladikimeleti.doc The first 10 export markets in 2005 (U.S.A., http://www.acci.gr : Athens Chamber of Commerce Saudi Arabian, China, Cyprus, Japan, Brazil, & Industry. Spain, Italy, Germany, and Hong Kong.) occupy http://www.statistics.gr : National Statistics Service a share of 68% in value of total exports (107.5 of Hellas (NSSG). million €). The first 10 export markets in 2005 Laskaridis, K., 2004. Greek Marble through the ages: An overview of geology and the today stone sec- occupy a share of 53.8% in quantity of total ex- tor. Final OSNET Workshop Ioannina, Hellas, 30 ports, with China having by far the largest Sep. 2004, 17 pp. share of Hellenic exports (35%). The main mar- Marmaro, Special Edition, Marmin 2006. Business kets for Hellenic marble in 2005, according to Data Ltd., May 2006, 274 pp. quantity, were China, Hong Kong, U.S.A., Cy- Ornamental Stone from Greece, Editions Hellenic prus, Italy, Spain, Brazil, United Arab Emirates, Marble, Issue 23, May 2004, 146 pp. Germany, and Japan.

5. CONCLUSIONS

The Hellenic marble sector has a long tradition, and has managed to keep Hellas among the 10 most important marble producing and exporting countries in the World, despite increased competition.

Hellas offers a wide variety of marble of different aesthetic and technical characteristics appropriate for all uses. Modernised quarrying takes place all over Hellas. Commercial companies are active all over the World and promote Hellenic marble exports with the support of the Hellenic Foreign Trade Board (H.E.P.O.). The H.E.P.O. in collaboration with the I.G.M.E. have

Page 26 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

THE CONTRIBUTION OF PETROGRAPHY TO THE EVALUATION OF CARBONATE AGGREGATES FOR CONCRETE PRODUCTION

Marina Dimitroula Mineralogist ([email protected]) I.G.M.E., Division of Mineralogy & Petrography

Concrete Abstract Aggregates Concrete is the product of mixing aggregates with Portland cement and water. The mixture Deleterious consists of ~80% aggregates and ~20% cement by volume. The water/cement ratio is about 0.5. The dried mixture is a compact and dense material, known as “concrete”, which is widely Minerals used as a building material. The aggregates employed for concrete production are various rock types, which comply with National and/or International Specifications. In Hellas, the materials The Alkali-Silica normally used as aggregates are carbonate rocks, which are the most widespread nationally. Reaction The last are considered among the most suitable for concrete production, provided that they do not contain deleterious minerals. Such minerals are some disordered forms of silica, clays, Petrographical dolomite and others, which under special conditions can react with the cement paste, causing Evaluation an Alkali-Silica Reaction (ASR) and an Alkali-Carbonate Reaction (ACR), forming an alkali-silica gel, which swells and induces stress causing expansion and cracking of concrete. Over time, the continuous disintegration of concrete can threaten the structural safety of the construction.

Περίληψη

Η ΣΥΝΕΙΣΦΟΡΑ ΤΗΣ ΠΕΤΡΟΓΡΑΦΙΚΗΣ ΜΕΛΕΤΗΣ ΣΤΟΝ ΕΛΕΓΧΟ ΤΩΝ ΑΝΘΡΑΚΙΚΩΝ ΑΔΡΑΝΩΝ ΓΙΑ ΤΗΝ ΠΑΡΑΓΩΓΗ ΣΚΥΡΟΔΕΜΑΤΟΣ: Όπως είναι γνωστό, το σκυρόδεμα παρασκευάζεται από αδρανή υλικά (~80%), τσιμέντο Πόρτλαντ (~20%) και νερό (νερό:τσιμέντο = 1:0.5). Όταν τα αναμεμειγμένα υλικά πήξουν και στεγνώσουν, παράγουν ένα συμπαγές και ανθεκτικό τεχνητό πέτρωμα, το σκυρόδεμα, που χρησιμοποιείται ευρέως στις κατασκευές. Ως αδρανή υλικά για την παραγωγή σκυροδέματος χρησιμοποιούνται διάφοροι τύποι πετρωμάτων, αρκεί να πληρούν τις Εθνικές ή/και τις Διεθνείς Προδιαγραφές. Στην Ελλάδα τα πιο διαδεδομένα αδρανή για την παρα- γωγή σκυροδέματος είναι τα ασβεστολιθικά, επειδή προέρχονται από πετρώματα που βρίσκονται σε αφθονία στο μεγαλύτερο μέρος της χώρας. Τα ανθρακικά πετρώματα είναι από τα πλέον κα- τάλληλα για την παραγωγή σκυροδέματος, αρκεί να μην περιέχουν βλαπτικά συστατικά (προσμίξεις) και συγκεκριμένα ορισμένα ορυκτά (ή ουσίες) τα οποία(ες), ανάλογα με την ποσό- τητα και την κατανομή τους, μπορούν να επηρεάσουν αρνητικά την παραγωγή ενός καλού σκυ- ροδέματος. Τέτοια ορυκτά είναι ορισμένες ασταθείς μορφές του διοξειδίου του πυριτίου, τα αργι- λικά ορυκτά, ο δολομίτης και άλλα, τα οποία, κάτω από ορισμένες συνθήκες αντιδρούν με τα ορυκτά της πάστας του σκυροδέματος και παράγουν ένα αλκαλοπυριτικό ζελέ, το οποίο διογκώ- νεται και προκαλεί τάσεις, με αποτέλεσμα να δημιουργούνται ρωγματώσεις, οι οποίες με το πέρα- σμα του χρόνου απειλούν την ασφάλεια της κατασκευής.

1. INTRODUCTION

Concrete is the product of mixing The dried mixture is compact and aggregates (coarse and fine) with dense, known as “concrete”, which Portland cement and water. The ag- is widely used as a building con- gregates are, by volume, the major struction material. The aggregates constituents of concrete (~80%) employed in concrete production, and the rest is cement (~20%). The are various types of rocks, which water/cement ratio is about 0.5. comply with National and/or Inter- Water and cement form the paste, national specifications. In Hellas, the while the aggregates the inert filler. rocks usually used as aggregates for

Page 27 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

PETROGRAPHICAL EVALUATION OF CONCRETE AGGREGATES

concrete production are the carbonate rocks, ate minerals, calcite (CaCO3) and dolomite

which are the most abundant in the country. (Ca,Mg)CO3. A rock to be Carbonate rocks are considered among the classed as calcareous

most suitable for concrete production, provided should contain at least they do not contain deleterious minerals, which 50% lime-carbonate according to their quantity or distribution could minerals. Rocks con- have adverse effects on the production of a sisting largely of calcite “good quality” concrete. are termed as limestone; those containing additionally 2. DELETERIOUS MINERALS IN AGGREGATES Figure 1. 3 Microphotographs of disordered According to (a) the specification EN 12620 , forms of silica in limestone aggre- and (b) the 1997 Hellenic National specification gates (the insoluble material): for concrete production,6,7 the deleterious min- (a) The insoluble material of a erals contained in the aggregates are some dis- some limestone aggregates; ordered forms of silica (opal, chalcedony, (b) Radiolaria in some limestone aggregates (+N, x500); stressed quartz, volcanic glass), clay minerals, (c) Chalcedony with some calcite in the limestone aggregates (+N, x500); some magnesium minerals, coal, organic mat- ter, pyrite and others (Fig. 1). (d) Clayey material in limestone aggregates (+N, x500.

Sometimes, only a small quantity of these min- b erals in the aggregate can cause problems in c the concrete. There are guidelines stipulating that the aggregates should not contain more

than 2%, or less than 60% reactive silica.1,2 An- other example of deleterious minerals in small quantities, is the presence of sulphide and sul- phate minerals. According to EN 12620 (paragraph 6.3.2, b)3, total sulphur in the aggregates should not exceed 1% by weight (for fly ash it is 2%). If

pyrrhotite is present in the ag-

gregates, then the total sul- magnesium carbon- phur should not exceed ate are called dolomite 0.1%. Taking into account, or dolostone, and mix- the above mentioned min- tures of calcite and dolomite erals and quantities, it is are referred to as dolomitic lime- obvious, that aggregates stone or calcitic-dolomite, depending should be carefully exam- on the proportion of the main min- ined, before their use in eral. The term “magnesian limestone” concrete production. is applied by some to limestone con- d taining dolomite in amounts of less than 10%, while by others to limestone in 3. PETROGRAPHY OF which visible dolomite is lacking, but carries CARBONATE ROCKS considerable magnesium, as indicated by chemical analyses. Limestone is a relatively Limestone and dolomite, the principal calcare- pure carbonate rock. Accessory minerals are ous rocks, are composed essentially of carbon-

Page 28 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

PETROGRAPHICAL EVALUATION OF CONCRETE AGGREGATES

usually about 5% by volume. If the accessory ment. The reaction forms a swelling gel, which constituents are abundant, the rock name is may induce stress, resulting in expansion and modified accordingly to suit the particular com- cracking of the concrete, which over time can position. Glauconitic, cherty, sandy and argilla- threaten the safety of the whole structure. A ceous limestone types are particularly common. combination of the following factors may lead to Similar terms are applicable to dolomitic lime- ASR-induced cracking: stone, calcite-dolomite and dolomite. By in- • presence of disordered silica forms; creasing the content of non-carbonate materi- • available alkalis (generally from cement), als, calcareous rocks grade into other rock above a critical level, and types; thus, sandy limestone grades into calcareous sandstone, and argillaceous limestone • moisture from an external source. into marl and calcareous shale. The reactivity of silica depends on the degree of In calcareous sediments many minerals, other order in the crystal structure. Opal, is highly than carbonates, occur. Some are simply detri- disordered, and is the most reactive form of sili- tal or pyroclastic grains, washed or blown into ca. In contrast, well-ordered unstrained quartz the depositional basin, and mechanically mixed is usually non reactive. Other undesirable forms with carbonate material. There is no limit to the of silica are tridymite, cristobalite, chalcedony variety of rock particles and minerals that may (chert, flint, etc.), microcrystalline quartz, be included in this manner, but as may be ex- strained quartz and volcanic glass. There are pected, quartz and clay are the commonest. guidelines for minimising ASR in new construc- Other non-carbonate constituents are organic tions by using aggregates, which contain less remains, such as the opal of diatom and radio- than 2% by volume, or more than 60% reactive larian shells and sponge spicules; the cello- silica.1,2 phane of bones, teeth, and some brachiopod Another type of alkali-aggregate reactivity is shells; and the calcareous pigment, which dark- the Alkali-Carbonate Reaction (ACR), occurring ens many types of limestone. Authigenic miner- when certain carbonates react with alkalis to als may also be present. These may be formed, cause expansion and cracking.5 Potentially dele- either almost contemporaneously with the cal- terious carbonates are the dolomitic varieties, careous deposits, or later, during and after especially those with high clay content. There lithification. Among the commonest of these are a number of tests for assessing the reactiv- minerals are chalcedony, quartz, glauconite, ity of aggregates, such as the ASTM C289 quick 9 pyrite, gypsum anhydrite and alkali feldspars. test, the ASTM C227 mortar bar expansion test, and the gel pat test. Petrographical examination 4. LIMESTONE AND THE ALKALI-SILICA of aggregates is also an important assessment REACTION procedure (ASTM C295). In addition, Lorenzi et al.8 state that “the petrographical analysis Limestone aggregates for concrete production, points out opposite behaviours of the lime- should be hard, durable, clean, and mainly al- stones with regards the ASR. Some of these most free of clay and disordered forms of silica, rocks with silicifications show high reactivity or which, under special conditions, could react with no reactivity at all, while others, without visible the alkalis in the cement pore fluids, causing silicifications, can be reactive. Thus, the pres- Alkali-Silica Reaction (ASR) or Alkali-Carbonate ence of visible secondary diagenetic silica within Reaction (ACR), inducing expansion and crack- limestone is not a prerequisite to promote the ing in concrete. ASR is a chemical reaction be- Alkali-Silica Reaction, and the absence of visible tween disordered forms of silica, which may oc- silica does not necessarily mean that the lime- cur in aggregates, and hydroxyl ions, formed by stone is not reactive.” the release of alkali compounds from the ce-

Page 29 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

PETROGRAPHICAL EVALUATION OF CONCRETE AGGREGATES

5. PETROGRAPHICAL EVALUATION OF provided that it does not contain deleterious LIMESTONE AGGREGATES minerals. • The deleterious minerals in limestone are Taking into account: (1) the petrography of mainly the disordered forms of SiO2 and clay limestone (above) and its non-calcareous min- minerals. erals; (2) the minerals considered as deleteri- • Among the methods testing aggregate mate- ous for causing Alkali-Silica Reaction, and (3) rials for concrete production, petrographical the results of Lorenzi et al.8 that “the petro- analysis is considered a “must”. graphical analysis points out opposite behav- • Petrographical analysis alone is, however, not iours of the limestones, with regards the ASR”, sufficient to test the suitability of concrete it is concluded that limestone should always be aggregates. Similarly, chemical analyses and examined, according to National and Interna- durability tests alone or in combination, are also not adequate for testing concrete aggre- tional Specifications, although they are consid- gates. ered among the most suitable rocks for produc- Limestone aggregates are suitable for con- ing concrete aggregates. • crete production, provided they always com- It must also be emphasised, that petrographical ply with the recommended Aggregate Specifi- analysis is a very important “tool” for the cations, and their testing includes a combination of Durability Tests, Chemical and Petro- evaluation of concrete aggregates, because the graphical Analyses. use of different petrographical methods (Optical microscope, X-Ray Diffraction Analysis, Elec- REFERENCES tronic Microscope Analysis), offer rapid and very good results. Sometimes, use of the optical mi- 1. Concrete Society, 1999. Alkali-silica reaction: minimising the risk of damage to concrete. Technical Report 30. croscope is inevitable, because some minerals Concrete Society, London, 72 pp. like chalcedony, volcanic glass or stressed [www.concrete.org.uk]. quartz, are impossible to identify by other 2. Department of Transport, 1991. Specification of Highway Works. HMSO, London. methods. It should also be stressed that by 3. European Standard, 2002. EN 12620, Aggregates for studying the aggregates in thin section, the concrete. European Committee for Standardisation, Brussels, 47 pp. rock fabric is studied, especially the porosity of 4. Central Laboratory of Public Projects, 1997. Hellenic the rock, which plays a very important role for specifications for Concrete Production. Central Labora- the quality of concrete. Only petrographical tory of Public Projects, Ministry of Environment, Physical Planning and Public Works, Athena, Hellas, 58 pp. analysis gives full information about the quan- 5. Gillot, J.A. & Swenson, E.G., 1969. Mechanism of the tity, type, size, shape and distribution of pores alkali-carbonate rock reaction. Quarterly Journal Engi- neering Geology, 2, 7-23. in an aggregate (EN 12620 F.1.3 & F.2.2).3 6. Hellenic Organisation for Standardisation, 1985. Specifi- Petrographical analysis again, is probably one of cations of crushed aggregates for common concrete. the best methods to identify the Alkali-Silica ELOT document 408, Athena, 20 pp. Reaction in concrete. It is stressed that “the ex- 7. Hellenic Organisation for Standardisation, 1996. Tests for general properties of aggregates. Part 3: Procedure amination should be carried out by a qualified and terminology for simplified petrographic description. ELOT document 932.03, Athena, Hellas, 20 pp. geologist (petrographer), with experience in 6,7 8. Lorenzi, G., Guėdon-Dubied, S. & Antenucci, D., 2001. materials used in civil engineering”. The status of the reactive silica in the limestones sus- ceptible to the Alkali-Silica Reaction (ASR): Contribution of petrographic and SEM techniques. Proceedings of the 8th Euroseminar on microscopy applied to buildings ma- 5. CONCLUSIONS terials. Athena, Hellas, 4-7 September 2001, 626 pp. 9. Williams, H., Turner, F.K. & Gilbert, C.M., 1954. Petrog- Summarising the above concise account about raphy. An introduction to the study of rocks in thin sections. W.H. Freeman & Company, San Francisco, 406 pp. the characterisation of aggregates in concrete production, the following conclusions are made:

• Limestone is considered to be the most suitable rock for concrete aggregate production,

Page 30 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

RADIOACTIVITY CONTROL OF BUILDING AND DECORATIVE MATERIALS

Faedon Pergamalis, Dimitris E. Karageorgiou, Athanasios Koukoulis, Dimitris Persianis Geologists ([email protected] ) I.G.M.E., Division of Solid Fuel Resources

Decorative Abstract Materials Some constructional and decorative materials used in buildings exhibit high levels of radioactiv- Construction ity. Exposure to radioactivity has an accumulative effect on the human body. It is necessary, therefore, to check the level of emitted radioactivity in a specialised laboratory, not only on the Materials natural primary raw materials, but also on the final products. This test is not destructive, it supplements quality control of geogenic materials, and guarantees the safety of end products. Radioactivity

γ-radiation Περίληψη

Specific ΕΛΕΓΧΟΣ ΡΑΔΙΕΝΕΡΓΕΙΑΣ ΣΕ ΔΟΜΙΚΑ ΚΑΙ ΔΙΑΚΟΣΜΗΤΙΚΑ ΥΛΙΚΑ: Ορισμένα δομικά και διακο- Radioactivity σμητικά υλικά, που χρησιμοποιούνται στις κατασκευές κτιρίων παρουσιάζουν αυξημένη ραδιε- νέργεια. Η έκθεση στη ραδιενέργεια δρα συσσωρευτικά στον ανθρώπινο οργανισμό. Απαιτείται, λοιπόν, έλεγχος της εκπεμπόμενης ραδιενέργειας από εξειδικευμένο εργαστήριο, όχι μόνο των πρωτογενών υλικών, αλλά και των τελικών προϊόντων τους. Ο έλεγχος είναι μη καταστροφικός, συμπληρώνει τους ποιοτικούς ελέγχους στα γεωγενή υλικά και εξασφαλίζει τη διασφάλιση της ακινδυνότητας του υλικού.

1. INTRODUCTION

Public awareness has been raised in that they are accompanied by an recent years, both in Hellas and official certificate of radioactivity worldwide, with respect to the qual- measurement. ity of life, making imperative, therefore, the taking of certain precau- 2. RADIOACTIVITY IN tions. One such action concerns ex- GENERAL posure to increased radioactivity, which unintentionally is caused in As natural radioactivity it is defined the interior of buildings by a variety the γ-radiation of short wavelength, of construction materials. Events which is emitted by primary raw ma- that had been over emphasised from terials, and to which is added the time to time in the daily press may natural radioactivity from cosmic be recalled, as for example, the ex- radiation. In this way a natural aver- istence of radioactive casings, ce- age level of radioactivity is formed ment with increased radioactivity, (known as background radiation), coloured sanitary ware materials, as which is a characteristic feature of well as other decorative materials an area. for which there is great suspicion in What is important is for this natural the minds of consumers. radioactivity level not to be dis- It should be noted that in some turbed by the accumulation of mate- countries, the import of construction rials with increased γ-radiation, be- and decorative materials requires cause the effects of exposure on the

Page 31 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

RADIOACTIVITY CONTROL OF BUILDING AND DECORATIVE MATERIALS

human body are cumulative, causing with the passage of time malfunctions of the human cells. It is, therefore, necessary to minimise the exposure of the human body to elevated radioactivity background levels in the home and work environments. This can only be achieved by a strict control of the materials used in the construction of buildings.

The research of the Institute of Geology and Mineral Exploration (I.G.M.E) has on several occasions identified housing blocks, which use rocks with abnormal radioactivity that result in the entire block to have an intense radioactivity Figure 1. Cage of lead bricks. anomaly. In the interior of buildings, where mic radiation is practically minimised. One such there is an accumulation of such materials, and cage consists of lead bricks, each having dimen- especially in confined spaces that are not well sions of 10x10x10 cm, a total volume 0.5 m3 aerated, the levels of γ-radiation increase sig- and a weight of 350-500 kg (Fig. 1); other nificantly, posing, therefore, a health hazard. types of cages are shown in Figures 2 and 3. For the objective control of radioactivity the factor of “mass influence” is used. This means that a material with a large mass and low natural radioactivity is possible to exhibit higher radioactivity levels, in comparison to another with a smaller mass, but increased natural radioactivity. For this reason the term “specific radioactivity” is used, which is the ratio of the emitted radioactivity to the mass of the material, and it is a characteristic property attributed to each material, like its specific gravity and density. Thus, comparison of the level of γ-radiation between materials is made possible. Figure 2. Figure 3. Other types of cages for measurement of γ-radiation.

3. METHOD OF TESTING RADIOACTIVITY Measurement of radioactivity in the cage can be achieved by the use of either a crystal of NaI, The measurement of radioactivity must be car- which is activated by Thallium, or by the use of ried out in a lead cage, so that the effect of cos- a Germanium crystal of great purity, and a

Figure 4. Instruments for measuring α-radiation.

Page 32 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

RADIOACTIVITY CONTROL OF BUILDING AND DECORATIVE MATERIALS

maximum capability of distinguishing the en- monitor the geometrical characteristics of sam- ergy spectrum of γ-radiation, which is being ples, using a disc rock cutter, combined with

cooled with N2, in accordance with the arrange- the use of an α-radiation counter, enabling, ment being used. The radioactivity measure- thus, the estimation of “radioactivity balance”. ment system is accompanied by: It should be, • a pre-amplifier of the outgoing signal; however, noted that comparison • a processing unit of the signal, of substantial of materials capacity and speed, with built-in software, must be done and the necessary peripherals; on the same • an amplifier; measurement • a high resolution screen, and system, given that there Figure 7. Crystals for measuring γ-radiation. is a wide selection in size • a plotter. and quality of crystals, A necessary prerequisite is that samples of ma- which obviously have dif- terial being tested ferent behaviour (Fig. 7). should have prede- There are obviously sys- fined dimensions, tems that have the facility so as to minimise to both make a distinction even the slightest between the radiating elements and to produce difference in the measurements in international units measurements that (Becquerel). can be possibly The I.G.M.E. is equipped with radioactivity introduced by the Figure 5. Specific dimensions of geometry of the test samples. measurement instruments, which can estimate material (Fig. 5). the “specific radioactivity” of raw materials by examination of their quality and quantity char- The range of influ- acteristics, such as the chemical-mineral com- ence of the angle position, hardness, etc. during the measurement of radioactivity Hundreds of measurements of “specific γ- should preferably be radioactivity” have been conducted on terres- 2π, so that over or trial rocks (n=2,570), as well as on samples under estimations from sea bottom sediments (n=419), and their are avoided (Fig. 6). corresponding range and average values are 45-10,850 x 10-4 (mean 422 x 10-4) and 20-516 -4 -4 x 10 (mean 78 x 10 ) ch/gr.sec. Figure 6. Measuring the Below four indicative measurements of specific correct 2π angle. radioactivity of decorative rocks are given:

-4 Mass is measured in grams, while radioactivity • Hellenic marble 21 x 10 ch/gr.sec may be measured in the units of the instrument • Hellenic granite 104 x 10-4 ch/gr.sec being used. Usually ticks per second (chocks/ seconds), or units of radiation being absorbed • Imported granodiorite 222 x 10-4 ch/gr.sec (Becquerel or Micro Curie). • Imported aplite grano- 303 x 10-4 ch/gr.sec Apart from detecting unstable nuclei that are diorite responsible for the radioactivity, it is possible to

Page 33 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

RADIOACTIVITY CONTROL OF BUILDING AND DECORATIVE MATERIALS

Consequently, it would be advisable to monitor requisite. the level of radioactivity of imported materials, The cost of installation and operation of a labo- as well as to provide a certificate of radioactivity ratory of radioactivity measurement on con- for materials being exported. struction and decorative materials is relatively low, and its amortization favourable, let alone 4. AREAS OF APPLICATION - CLIENTS the fact that it gives the possibility to the I.G.M.E to develop an income from this source. The certificate of suitability may be issued for use by: On the other hand, the laboratory may be used for the measurement of radioactivity in residen- • Exporters of building materials; tial areas, as well as on raw materials for con- • Importers of decorative materials; struction of highways, railways, etc. Therefore, the completion of the I.G.M.E. «Radioactivity • Manufacturers and importers of sanitary ma- Control and Attestation of construction and terials, and decorative materials Laboratory» is considered • Manufacturers of cement products. essential to fill a regulatory gap in Hellas. In parallel, the laboratory may be used to ex- amine radioactive contamination of the geologi- BIBLIOGRAPHY cal environment of residential areas by State Authorities (I.G.M.E., Ministry of Environment, Dumoulin, C., 1980. Methodes de Prospection de l’ Uranium. COGEMA / C.I.P.R.A., France, 141 pp. Physical Planning and Public Works). Pergamalis, F., 1998. Feasibility Study for the estab- lishment of a laboratory for the radioactivity con- 5. ESTIMATE OF COST FACTORS trol of construction materials. I.G.M.E internal report, Athena, 5 pp. Market research has shown that the cost of a fully equipped radioactivity measurement labo- Pergamalis, F., Karageorgiou, D.E. & Koukoulis, A., ratory, including software and peripherals, is 2000. Radioactivity control of building materials. Proceedings of 3rd Congress of Mineral Research, about €60,000 excluding V.A.T. If an amortiza- Technical Chamber of Hellas, Athena, 383-386. tion time of 10 years is accepted, although the unit has an unlimited life span, it is concluded that the depreciation for each working day costs about €25. Consequently, the estimated daily operation cost of the laboratory is €115, which more than sufficiently covers the cost of amortization.

6. CONCLUSIONS - PROPOSALS

Emission of radioactivity by various construction and decorative materials poses a serious health hazard in the home and work environments. Lack of knowledge of radioactivity levels emitted by these materials cannot be justified. Suit- ability certificates for the export and import of all construction and decorative materials will soon be compulsory in all EU States, although in certain countries it is already a necessary pre-

Page 34 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

AN OVERVIEW OF THE INDUSTRIAL MINERAL RESOURCES OF GREECE

Dr. Ioannis Marantos Geologist ([email protected]) I.G.M.E., Division of Economic Geology Kiki Hatzilazaridou Geologist ([email protected]) I.G.M.E., Division of Development and Planning

Industrial Minerals Abstract

Endogenous The Greek geological domain is composed of pre-alpine crystalline rocks, alpine sediments, Deposits volcanosedimentary formations, and oceanic crustal and post alpine sedimentary-volcanic rocks. The Hellenides are subdivided into a number of geotectonic units, grouped into “Internal” Exogenous Deposits and “External” ones. The complex geological structure of Greece favoured the formation of various types of mineral resources. The Internal Hellenides, host a variety of industrial minerals, Hellenides formed either by magmatic or metamorphic processes (Endogenous Deposits). Several important Industrial Mineral prospects and deposits have been located in the Internal Hellenides including: olivine, magnesite, talc, vermiculite, feldspar, quartz, graphite, garnet, wollastonite, pumice, perlite, bentonite, kaolin, zeolites, pozzolana, etc. The External Hellenides are characterised by the presence of Industrial Minerals of sedimentary origin (Exogenous Deposits), including outcrops/deposits of bauxite, gypsum-anhydrite, white carbonate, attapulgite, phosphate, diatomite, etc. Exogenous deposits of weathering origin (quartz-feldspar sand, silica sand, kaolin), may be hosted in both the External, and Internal Hellenides. Taking into account that (a) the mining industry is a driving factor in human development, (b) industrial minerals are fundamental constituents for various fields of modern life, (c) technological innovations are increasing further their consumption by expanding the fields of their application, and (d) the geological structure of Greece favours the formation of a wide variety of industrial mineral occurrences/ deposits, thus, a continuous development of the industrial mineral sector is expected.

Περίληψη

AΝΑΣΚΟΠΗΣΗ ΤΩΝ ΒΙΟΜΗΧΑΝΙΚΩΝ ΟΡΥΚΤΩΝ ΤΗΣ ΕΛΛΑΔΑΣ: Ο Ελλαδικός χώρος υποδιαιρείται σε μία σειρά γεωτεκτονικών ζωνών, τις «Ελληνίδες», οι οποίες δομούνται από γεωλογικούς σχη- ματισμούς προαλπικής ηλικίας, αλπικά ιζήματα, ηφαιστειοϊζηματογενή και οφιολιθικά πετρώματα, μετα-αλπικά ιζηματο-πυριγενή πετρώματα, που ομαδοποιούνται σε «Εσωτερικές» και «Εξωτερικές». Η πολυπλοκότητα και η ποικιλία των γεωλογικών σχηματισμών και η γεωλογική εξέλιξη του ελλαδικού χώρου, έχουν οδηγήσει στη δημιουργία σημαντικού αριθμού εμφανίσεων/ κοιτασμάτων ποικίλων βιομηχανικών ορυκτών. Λόγω της γεωλογικής δομής και της εξέλιξής τους οι Εσωτερικές Ελληνίδες φιλοξενούν κυρίως βιομηχανικά ορυκτά που δημιουργήθηκαν από μαγματικές ή μεταμορφικές διεργασίες (ενδογενή). Στις Εσωτερικές Ελληνίδες έχουν εντοπιστεί σημαντικές εμφανίσεις/κοιτάσματα ολιβινίτη, αστρίων, χαλαζία, βολλαστονίτη, γρανατών, κυανί- τη, γραφίτη, τάλκη, βερμικουλίτη, μαγνησίτη, ποζολάνης, κίσσηρης, περλίτη, ζεολίθων, μπεντο- νίτη, καολίνη κλπ. Στις εξωτερικές Ελληνίδες απαντούν κυρίως βιομηχανικά ορυκτά ιζηματογε- νούς προέλευσης (εξωγενή), ανάμεσα στα οποία είναι οι βωξίτες, οι φωσφορίτες, οι γύψοι, τα λευκά ανθρακικά, οι διατομίτες, ο αταπουλγκίτης κλπ. Τόσο στις εσωτερικές, όσο και στις Εξωτε- ρικές Ελληνίδες, μπορεί να απαντούν εξωγενούς γένεσης βιομηχανικά ορυκτά που δημιουργήθη- καν από διαδικασίες αποσάθρωσης, όπως χαλαζιο-αστριούχες άμμοι, πυριτικές άμμοι, καολίνης, κλπ. Η εκμετάλλευση κοιτασμάτων βιομηχανικών ορυκτών αποτελεί ένα αξιόλογο τμήμα της ελληνικής εξορυκτικής βιομηχανίας. Το συντριπτικά μεγαλύτερο μέρος της αξίας της παραγωγής προέρχεται ουσιαστικά από λίγα μόνο βιομηχανικά ορυκτά, όπως μπεντονίτης, περλίτης, χουντί- της, κίσσηρις. Άλλες ορυκτές πρώτες ύλες που εξορύσσονται είναι χαλαζίας, άστριοι, καολίνης, ποζολάνη, γύψος, πυριτικό, λευκά ανθρακικά, μαγνησίτης, ολιβινίτης και περιστασιακά ζεόλιθοι.

Page 35 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

OVERVIEW OF THE GREEK INDUSTRIAL MINERAL RESOURCES

1. INTRODUCTION and clastic sediments). An Industrial Mineral (IM), as defined in the The External Hellenides consist of the following Glossary of Geologic Terms, is “any rock, geotectonic zones: (a) Pindos, (b) Gavrovo- mineral, or other naturally occurring sub- Tripolis, and (c) Paxos. Depending on the zone, stance of economic value, exclusive of metal- they are mainly made up of neritic to pelagic lic ores, mineral fuels, and gemstones; one of sediments (carbonates, shale, mudstone, radio- the nonmetallics.”2 They may be classified larite, flysch). In certain zones, bauxite hori- into various groups using different criteria, zons, evaporites, volcanic and slightly meta- such as fields of application (construction, morphosed rocks, may occur. chemical industry, glass and ceramics, fillers- During Palaeogene, the intense alpine orogenic extenders, etc.), geological criteria, or taking phase produced post alpine sedimentary basin into consideration commercial/trading crite- formations. The subsequent sedimentation was ria.13,43 accompanied by intense collision type magma- Industrial minerals occur in igneous, meta- tism that produced volcanic, sub-volcanic and morphic and sedimentary rocks, and may plutonic rocks. The oldest magmatic rocks occur have been formed either by syngenetic or in Thrace, where as the most recent ones are epigenetic processes in relation to their host found in the still active Hellenic arc. rocks. In this article the Industrial Mineral resources (construction mineral resources are 3. INDUSTRIAL MINERALS OF GREECE excluded) are discussed, according to their The complex geological structure of Greece geological setting and processes that fa- favoured the formation of various types of voured their formation. mineral resources. The Internal Hellenides, due to their constitution and evolution, host a 2. GEOLOGICAL SETTING OF GREECE variety of mainly endogenous industrial min- The Greek geological domain is a part of the erals; these are formed either by magmatic Alpine Dinaric Arc and is referred to as processes, including magma differentiation, “Hellenides”. It is composed of pre-alpine contact metasomatism, and hydrothermal ac- crystalline rocks, alpine sediments, volca- tivity, or by metamorphic processes, including nosedimentary rocks, and oceanic crustal and contact-regional metamorphism.13 The Exter- post alpine sedimentary-volcanic rocks. The nal Hellenides are characterised mainly by the Hellenides are subdivided into a number of presence of industrial minerals, mostly of geotectonic units, grouped into “Internal” and weathering or sedimentary origin (Exogenous “External” (Fig. 1). The Internal Hellenides deposits), according to the same classification have undergone deformation during two oro- model. genic cycles; the first in Late Jurassic-Early 3.1. Endogenous Type IM Resources Cretaceous times, and the second during the Tertiary. The External Hellenides have been 3.1.1. Mineral Occurrences of Primary Magmatic affected only by the last orogenic cycle. Origin Olivine: Widespread ophiolite outcrops occur in The Internal Hellenides are comprised of the Greece (Pindos, Vourinos, Chalkidiki, Thrace, following geotectonic zones: (a) Rhodope, (b) Orthrys, etc.). Therefore, theoretically, there is Serbo-Macedonian, (c) Circum-Rhodope, (d) a very high potential for the location of large Axios-Vardar, and (e) Pelagonian. These dunite (olivine) deposits. On the other hand, the zones consist mainly of low to high-grade requirements of industry for unaltered olivine, metamorphic rocks (schist, gneiss, amphibo- in relation to the history of the ophiolite com- lite, migmatite, anatectic granite, carbonate plexes, narrows the chances of finding fresh de- rocks, phyllite, mafic and ultramafic rocks,

Page 36 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

OVERVIEW OF THE GREEK INDUSTRIAL MINERAL RESOURCES

posits. Occurrences of fresh olivine, suitable for lands, and in the area of Alexandroupolis high quality olivine products, have been located (Thrace) on the Greek mainland.18,20,21,22,55 at Gerakini and Vavdos areas of Chalkidiki, as Zeolites are usually products of alteration of well as in the ophiolitic complexes of Vourinos the glass of volcaniclastic rocks, under diage- and Pindos.1,8 netic or low temperature hydrothermal condi- Pegmatites, the last stage product of magma tions. Large zeolite deposits of possible eco- crystallisation (in certain cases may be products nomic significance occur in Thrace (Petrota, of anatectic processes), are the main source of Pentalofos, Lefkimi, Feres, Skaloma), and on K- or Na-feldspars, mica and quartz by-products some Aegean islands (Thira, Polyegos). Less (simple pegmatites). Apart from these, high important occurrences exist on the islands of rare mineral concentrations, such as beryl, to- Lesvos, Milos, etc.34 paz, etc., may be hosted in “complex pegma- Kaolin occurrences, formed by hydrothermal tites”. Widespread outcrops of simple type peg- alteration of volcanic rocks, are widespread in matites have been located in metamorphic Greece, e.g., Thrace, Macedonia, Lesvos, Milos, rocks in the Rhodope and Vertiskos zones Kimolos, etc.17,20,24,53 Due to their origin, they (Protoklissi-Koryvos, Leptokarya, Paranesti, As- usually form veins in altered volcanic rocks. siros).9,31 Their composition varies widely, and usually Natural Pozzolanas, are materials of silica- they are not of good quality as they contain Fe, alumina composition, which in the presence of S, silica and other impurities. Deposits of hydro-

water react with Ca(OH)2 to produce com- thermal alteration of volcanic origin have been pounds with hydraulic properties. Volcanic rocks exploited in the past on the islands of Milos and with pozzolanic properties are widespread in Lesvos. Greece. Large deposits of pozzolanic rocks occur Bentonite deposits may be formed either by on the islands of Milos and Santorini, as well as diagenetic alteration of volcaniclastic rocks, or in the area of Aridea. Less important outcrops by hydrothermal alteration. Large bentonite de- are located on the islands of Kimolos, Nisyros posits occur on Milos Island. Less important oc- and Kos, as well as in some areas in Thrace.23 currences and deposits also exist on the islands Pozzolanic properties are also displayed by zeo- of Kimolos, Chios, Lesvos and Samos, and in litic tuffs (Polyegos, Dadia, etc.).29 Thrace.3,4,20,35 Pumice, is light in colour, highly vesicular and Feldspars: Large deposits of volcaniclastic lightweight rock, formed during the eruption of rocks, rich in secondary K-feldspar, have been silicic magmas with a high volatile content. Ex- located in the area of Vani on Milos Island. The tensive exploitable pumice deposits exist on K2O percentage of the rock is of over 10%, and Santorini and Yali islands. Fe2O3 varies from 1 to 2%. Beneficiation stud- 3.1.2. Mineral Occurrences Related to Alteration ies, carried out by the I.G.M.E., produced con- of Volcanic Rocks centration of potassium feldspar with less than 28 Perlite, possibly formed by alteration of vol- 0.1% Fe2O3, and barite as a by-product. canic glasses under the influence of hot va- Silica, amorphous (opal) or microcrystalline pours, is light coloured, water bearing glassy quartz, formed by hydrothermal alteration of volcanic rock, usually of rhyolitic composition. It volcaniclastic rocks, occur on the island of expands to about 10-15 times its original vol- Milos,14 as well as in other areas with intensive ume, after rapid heating at a certain tempera- post volcanic hydrothermal activity. ture. Large perlite deposits have been located on the islands of Milos and Yali. Less important 3.1.3. Mineral Occurrences Related to Contact Metasomatism outcrops occur on Kos, Kimolos and Lesvos is- Wollastonite is usually a product of contact

Page 37 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

OVERVIEW OF THE GREEK INDUSTRIAL MINERAL RESOURCES

Figure 1. Map of the Geotectonic Zones, Ophiolites and Volcanic Rocks of Greece.36

▲ industrial mineral occurrences, 0 industrial mineral mines [As=asbestos; At=attapulgite; Be=bentonite; Ba=barite; Ca=calcium carbonate; Di=diatomite; Do=dolomite; Em=emery; Fd=feldspar; Gr=graphite; Grn= garnet; Gy=gypsum; Ha=halite; Hu=huntite; Ka=kaolin; Mg=magnesite; Ol=Olivine; Pe=perlite; Ph=phosphates; Pt=stonewool; Pu=pumice; Pz=pozzolana; Qz=Quartz (quartz veins; sands); Si=silica; Ss=silica/silica-alumina sand; Tc=talc; V=vermiculite; Wo=Wollastonite; Ze=zeolite].

Page 38 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

OVERVIEW OF THE GREEK INDUSTRIAL MINERAL RESOURCES

metasomatic reactions, forming exoskarn or en- on the mainland.5,12 doskarn deposits at the contact of marble and 3.1.3. Mineral Occurrences Related to Metamor- intrusive rocks. Known skarns, with important phic Processes wollastonite outcrops, occur at Panorama near Kyanite is hosted in Al-rich rocks, metamor- Drama, as well as in the area of Kimeria village, phosed under Barrovian upper amphibolite fa- near Xanthi; estimated reserves in these areas cies conditions. Minerals of the sillimanite group are around 500 and 700 thousand tonnes, re- are common constituents of metamorphosed spectively.10,11 The Panorama wollastonite de- rocks in Rhodope.35 Non-economic kyanite out- posit contains more than 50% wollastonite, and crops have been described on the islands of is possibly suitable for filler in ceramics, some Thassos and Naxos.30,42 metallurgical applications, and as a partial sub- stitute material for asbestos in the asbestos- Graphite: Flake and microcrystalline graphite cement industry. outcrops occur in gneiss, schist and marble, of Garnet prospects are mainly developed by me- the Rhodope Zone (Thermes, Polyneri), in the tasomatic reactions near the contact of acid in- Serbomacedonian Zone (Vavdos), as well as in trusives and calcareous rocks, and in metamor- the Circum-Rhodope Zone (Makri). In the area phic rocks. On the island of Serifos, significant of Thermes (Xanthi Prefecture), a flake graphite occurrences of garnetite, suitable for abrasives outcrop has been located with estimated re- and liquid filtering, have been located. The esti- serves exceeding 600,000 tonnes of ore, and a 9,41,54 mated reserves are around 1.5 Mt, with possibly graphite content of 3-12%. 400-500,000 tonnes of exploitable garnetite un- Quartz: Significant quantities of vein quartz, 37 der open pit conditions. Large garnet pros- suitable for the ceramic and glass industries, pects also occur at Panorama, and in the area are hosted in gneiss and schist in the Rhodope, of Kimmeria, near Xanthi. The resources of gar- Serbo-macedonian, Circum-Rhodope and netite of andraditic composition of the Kimmeria Pelagonian Zones.1,16 prospect are estimated at about 1 Mt.16 Labora- tory and mineral processing tests, carried out Chrysotile asbestos, formed under low grade within the framework of an E.U. funded project, metamorphic conditions in entirely serpen- showed that the Xanthi garnet is suitable for tinised dunite, in the Zindani area (near Kozani) 44 sand blasting in metal finishing.32 has been mined till lately. The mining activities in the area ceased in 2003. The use of as- Talc and Soapstone occur in metasomatic bestos is entirely forbidden in all European Un- zones that have been developed mainly at the ion countries, since 2005, according to Euro- contacts of serpentinised ultramafic bodies and pean Union legislation.47 surrounding gneiss or schist in Chalkidiki (Vertiskos Unit) and Organi-Myrtiski-Chloi Emery, called “smyris” (“σμύρις”) by ancient (Rhodope Zone).6,35,57 Greeks, “naxium” by the Romans (from Naxos Island where it was originally mined) was pro- Vermiculite prospects of some significance are duced since the Classical Greek Era on the is- located along the tectonised serpentinite-gneiss land of Naxos. The ancient mines are located on contacts in the Vertiskos Unit (Chalkidiki).7,58 the northern part of the island in the area of Magnesite deposits of cryptocrystalline type Koronos. The deposits form lenses of variable are developed in veins, stockwork, or irregular size, and were formed by metamorphism of pre- masses, hosted in ultramafic rocks. Major de- existing bauxite deposits. Bauxites were meta- posits occur in the Chalkidiki peninsula (Vavdos, morphosed to diasporites at lower tempera- Gerakini) and on the island of Evia (Mantoudi, tures, and corundum-rich rocks at higher tem- Limni). Less important outcrops exist on Lesvos peratures, during the Caenozoic.49 Island and in the areas of Ermioni and Kozani

Page 39 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

OVERVIEW OF THE GREEK INDUSTRIAL MINERAL RESOURCES

3.2. Exogenous Type Industrial Mineral I.G.M.E.50 Resources Silica, Quartz and Quartz-Feldspathic Sand, Gypsum-Anhydrite: Extensive gypsum- occur at various places in Greece. They may anhydrite deposits of Permo-Triassic and Neo- have been formed by weathering of (a) meta- gene age have been located in western Greece morphic rocks in the areas of Evros, Serres and (Zakynthos Island, Aitolia-Akarannia, Kastoria; (b) granite in the Sithonia-Kassandra Thesprotia, Peloponissos) and on Crete Island areas of Chalkidiki peninsula, on the island of 19,39,40 (Sitia and Hania). Ikaria in the Aegean Sea, etc.; (c) cherts in the White carbonates include calcium carbonate, External Hellenides (e.g., area of Velika in dolomite and huntite. Filler grade calcium car- Messinia).9,25,26,31,56,59 In most cases, sands con- bonates, derived mainly from pure white friable tain considerable amounts of feldspars, or other microcrystalline limestone (on Kephallonia and impurities, making them suitable only for con- Zakynthos islands), dolomitic and calcitic lime- struction applications. In the area of Argos stone and marble (Korinthos, Kavala, Thassos Orestiko (Kastoria) a silica sand deposit has Island, Vermion).33 Dolomite is widespread in been discovered, with total estimated reserves Greece, but production is restricted. Huntite de- of over 1.2 Mt. Beneficiation tests on the latter posits occur in the Upper Neogene lacustrine deposit produced concentrations with 92-94%

formations of the basin in the Kozani–Aiani- SiO2 and 0.04-0.08% Fe2O3, suitable for the ce- Servia area, associated with other Mg-rich car- ramic and glass industries.56 bonates, mainly hydromagnesite and magne- The weathering of Palaeozoic leucocratic or- site.52 thogneiss, formed the residual type kaolin de- Palygorskite, Atapulgite: Large size and high posits that occur in the area of Lefkogia, near quality palygorskite deposits, originating proba- Drama. The intense kaolinisation of either sodic bly by diagenetic transformation of pre-existing plagioclase or K-feldspar precursors is associ- sandy smectitic material, have recently been ated with large tectonic fault lines, which de- discovered in the Ventzia basin (Western Mace- lineate the Lefkogia graben.38,48 donia).27

Phosphate occurrences of Jurassic and Late 4. INDUSTRIAL MINERAL MAIN CENTRES Cretaceous age, exist in the Ionian and Parnas- OF PRODUCTION 51 sos Zones. Occurrences of phosphates in Neo- The most important production centres of In- gene sediments also exist on the islands of dustrial Minerals in Greece are the Aegean sea 45 Crete and Kefalonia and in Thessaly. islands of Milos, Yali and Crete, and many other Diatomite: Several occurrences, formed in locations in northern and western mainland. lacustrine or marine environments, have been More specifically, bentonite, perlite, pozzolana, located on the islands of Samos, Crete and Za- kaolin, and silica are extracted from various de- 46 kynthos, and in the Kozani area, etc. posits on Milos Island. Most of the perlite pro- Borate minerals, colemanite-ulexite have been duction, and all of bentonite output, come from recognised in lacustrine sediments in Karlovassi Milos, while kaolin is currently extracted from basin (Samos Island).15 two deposits, operated by one company located on Milos Island. Perlite is also extracted Rock Salt, is a chemogenic rock,14 formed by from Yali Island, which is the only, and most evaporation of saline water of various origin. important exploitation centre, for pumice. Poz- Rock salt has been mined occasionally, in the zolana is extracted also from the Skydra region near past, from Monolithi area, Ioannina Prefec- in Northern Greece. ture. About 95 Mt of salt containing around 80% NaCl, has been discovered by the The most significant gypsum production centre

Page 40 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

OVERVIEW OF THE GREEK INDUSTRIAL MINERAL RESOURCES

is the Altsi deposit in Eastern Crete. Periodically, nological developments are increasing further minor quantities are extracted from the Stomio their consumption by expanding the fields of deposit (western Crete) and Zakynthos Island their application. Although minerals are non- (Ionian Sea). The Katouna deposit in Western renewable resources, it is not anticipated that Greece produces gypsum for other than cement there will be any shortage of mineral resources uses. in the foreseeable future.

The only magnesite operation and plant are lo- As the geological structure of Greece favours cated at Yerakini, Chalkidiki region in Northern the formation of a wide variety of Industrial Greece. One company operates the two active Mineral occurrences/deposits, and in view of mines of huntite at Neraida, Kozani area in new technological developments, prospecting North-Western Hellas. for new, or re-evaluation of old deposits, should continue in order to assure a continuous devel- One company in the Kozani region, North- opment of the industrial mineral sector. Apart Western Greece, operates three deposits of at- from the exploration efforts, perspectives for tapulgite. The company has also a processing further development of the sector should plant in the nearby region of Grevena. broadly address the following issues: The small-scale production of olivine is derived • Sustainable exploitation of industrial minerals from the Skoumtsa deposit, Grevena region, through the development of new and/or envi- North-Western Greece. One company extracts, ronmentally friendly technologies; from various small deposits in Northern Greece, • The taking of measures to decrease environ- quartz and sodium-feldspar. mental and social impacts (focus on extrac- Stonewool products are produced by one com- tion and processing, minimisation of pro- pany in the area of Terpni (Serres). The raw duced waste); material mainly consists of amphibolite, with • Utilisation of by-products derived from min- minor amount of limestone and bauxite. ing-processing operations; Finally, Kefallonia Island with the deposit of • Increase efforts for market penetration and microcrystalline limestone, operated by one development of new products, and company, is the most important exploitation • Intensify efforts for quality improvement and centre of filler grade white calcium carbonates. innovation. Residues stemming from the white marbles’ exploitation in the Veria, Drama, and Kavala re- REFERENCES gions in Northern Greece, as well as in Attiki,

are currently used as a significant source for 1. Αrvanitidis, N., 1998. Northern Greece’s industrial min- filler grade white carbonate raw materials pro- erals: production and environmental technology development. Journal Geochemical Exploration, 62, 217-227. duction. Dolomitic marble from the Korinthos area is additionally used as raw material for 2. Lefond, S. 1975. Industrial Minerals and Rocks. Ameri- filler grade white carbonate production.60,61 can Institute of Mining, Metallurgical, and Petroleum Engineers, Inc., New York, 3 pp.

3. Christidis, G., Scott, P.W. & Markopoulos, Th., 1995. 5. KEY CHALLENGES FOR THE Origin of the bentonite deposits of Eastern Milos, Ae- INDUSTRIAL MINERALS SECTOR gean, Greece: Geological, mineralogical and geochemical evidence. Clays and Clay Minerals, 43(1), 63-77. Industrial Minerals, and derived processed products, are fundamental constituents of various 4. Christidis, G., Marcopoulos, Th. & Foscolos, A., 1999. fields of modern life, including such industries Origin, and physical properties of a bentonite deposit of Chios Island, Eastern Aegean, Greece. Proceedings of as construction, chemical and fertiliser, ceram- the 11th International Clay Conference Ottawa, Canada, ics, paper, plastics, as well as in agriculture, 75-82.

environmental protection etc. In addition, tech- 5. Dabitzias, S., 1980. Petrology and genesis of the Vavdos

Page 41 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

OVERVIEW OF THE GREEK INDUSTRIAL MINERAL RESOURCES

cryptocrystalline magnesite deposits, Chalkidiki penin- Milos. I.G.M.E. Internal Report, 21 pp. sula, Northern Greece. Economic Geology, 75, 1138- 1151. 25. Kastritis, I., 1994. Silica sand study of Skalohori (Kozani) and Spilaio (Kastoria). I.G.M.E. Internal Report, 6. Dabitzias, S., 1994. Exploration for talc location in areas 31 pp. of Verstiskos and Arnissa formations. I.G.M.E. Internal Report, 24 pp. 26. Katsritis, I. & Hatzilazaridou, K., 1992. Evaluation of Research industrial minerals resources of Ikaria Island. 7. Dabitzias, S. & Perdikatsis, V., 1991. Occurrences of I.G.M.E. Internal Report, 20 pp. vermiculite with economic interest in the area of Askos, Thessaloniki Prefecture. Bulletin Geological Society 27. Kastritis, I., Kacades, G. & Mposkos, E., 2003. The paly- Greece 25(2), 355-367. gorskite and Mg-Fe-smectite clay deposits of the Vetzia basin, western Macedonia, Greece. In: D. Eliopoulos et 8. Dabitzias, S. & Rassios, A., 2000. Hartzburgite/dunite for al. (Editors), Mineral Exploration and Sustainable Devel- olivinite products of high quality in ophiolite complexes opment. Millpress, Rotterdam, 891-894. of Vourinos and Pindos. Proceeding of the 1st Congress of the Committee of Economic Geology, Mineralogy & 28. Kelepertzis, A. & Charalambidis, P., 1994. The tuffite of Geochemistry, Geological Society of Greece, 330-340. Vani area, Milos Island, as mineral source for production of K-feldspar concentration and barite. Mineral Wealth, 9. Diakakis, E. & Stefanidis, P., 1994. Atlas of mineral re- 88, 7-12. sources of Central Macedonia. I.G.M.E. Internal Report, 185 pp. 29. Kitsopoulos, P.K. & Dunham, A.C., 1996. Heulandite and mordenite-rich tuffs from Greece: a potential source for 10. ELKE, Mineral resources. [http://www.elke.gr/] pozzolanic materials. Mineralium Deposita, 31, 576-583. 11. Georgiades, G., 1988. Greek raw materials for the glass 30. Kosharis, G., Karantassi, S. & Hatzilazaridou, K., 1989. and ceramic industry. Industrial Minerals, 47, 135-141. The kyanite of Naxos Island. I.G.M.E. Internal Report, 12. Gartzos, E., 2004. Comparative stable isotopes study of 24 pp. the magnesite deposits of Greece. Bulletin Geological Society of Greece, 36, 196-203. 31. Kosharis, G. & Vougioukas, D., 1980. Industrial mineral research in Evros Prefecture. I.G.M.E. internal Report, 13. Harben, P.W. & Kuzvart, M., 1996. Industrial Minerals: A 27 pp. Global Geology. Metal Bulletin, 462 pp. 32. Lambrakis, D. & Panagopoulos, K., 2000. Evaluation of 14. Hatzilazaridou, K, 2002. A review of Greek industrial Hellenic Industrial minerals as blast cleaning abrasives minerals. In: P.W. Scott & C.M. Bristow (Editors), Indus- for sandblasting. Technical Chamber of Greece, Proceed- trial Minerals and Extractive Industry Geology. Geologi- ings of 3rd Congress on Mineral Wealth, Vol. Α, 579-588. cal Society of London, 115-122. 33. Laskaridis, K., 1994. Greek white calcitic marbles. In- 15. Helvaci, C., Stamatakis, M.G., Zagouroglou, C. & dustrial Minerals, April 1994, 319, 53-57. Kanaris, J., 1993. Borate minerals and related authigenic silica in Northerneastern Mediterranian Late Miocene 34. Marantos, I., 2004. Study of the Tertiary volcanic rocks continental basins. Exploration Mining Geology, 2(2), alteration in the Feres basin of Evros Prefecture, empha- 171-178. sising on the genesis of zeolites and their possible applications. Unpublished Ph.D. thesis. Technical University 16. Kaklamanis, N., Theodoroudis, A., Arvanitidis, N., Filip- of Crete, Department of Mineral Research Engineering, pou, St., Tarenidis, D. & Pefani, V., 2006. Quartz. Chania, Greece, 264 pp. I.G.M.E. Internal Report, 64 pp. 35. Marantos, I. & Kosharis, G., 2003. Industrial minerals 17. Kanaris, I., 1977. Kaolines and other clays of Lesvos and rocks in the area of Eastern Macedonia – Thrace, island. I.G.M.E. Internal Report, 28 pp. Greece. Researches, results and prospects. In: I. Anas- 18. Kanaris, I., 1980. The perlite deposits of Milos. I.G.M.E. tasiadis (Editor) Proceedings of 50 years anniversary of internal report, 18 pp. Geological Society of Greece, 77-88.

19. Kanaris, I., 1989. Gypsum deposits of Crete Island. 36. Matarangas, D. & Triadafyllidis, E., 2005. Geological map I.G.M.E, Internal Report, 63 pp. of Greece. Scale 1:1000000. I.G.M.E. digital map.

20. Kanaris, I., 1995. The industrial minerals and rocks of 37. Papastavrou, S. & Perdikatsis, V., 1991. The garnetite Kimolos island. I.G.M.E. Internal Report, 31 pp. from Serifos. Bulletin Geological Society Greece, 35(2), 291-300. 21. Kanaris, I. & Chatzidimitriadis, E., 1972. Exploration for industrial minerals on the island of Lesvos. I.G.M.E. In- 38. Papoulis, D. & Tsolis-Katagas, P., 2001. Kaolin deposits ternal Report, 56 pp. of Lefkogia, Rhodope, Greece: process of kaolinization. Bulletin Geological Society Greece, 34(3), 875-882. 22. Kanaris, I. & Kosharis, G., 1978. The perlites of Kefalos peninsula, Kos Island. I.G.M.E. Internal Report, 33 pp. 39. Pitsikas, L., 1991. Gypsum deposits of Zakynthos Island. 23. Kanaris, I. & Markoulis, M., 1983. The pozzolanic earths I.G.M.E. Internal Report, 24 pp. of Milos Island. I.G.M.E. Internal Report, 25 pp. 40. Pitsikas, L., 1992. Gypsum Triassic deposits of Aito- 24. Kanaris, I. & Minopoulos, P., 1979. Preliminary report on loakarnania Prefecture. I.G.M.E. Internal Report, 26 pp. research of kaoline-bentonite deposits on the island of

Page 42 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

OVERVIEW OF THE GREEK INDUSTRIAL MINERAL RESOURCES

41. Ploumis, P. & Hatzipanagis, I., 1993. Amorphous graph- samples from the Askos area. I.G.M.E., Internal Report, ite occurrences in schists of alternation series in the area 20 pp. of Polyneri, Psili Rahi, Agios Panteleimon. I.G.M.E. Inter- 58. Chalkiopoulou, F., Kaklamanis, N., Kanaris, I. & Kravas, nal Report, 15 pp. Ch., 1985. Separation of feldspar and quartz from gran- 42. Ploumis, P. & Zachos, S., 1990. The kyanite of Thassos. ite. 1st Congress for Non Metallic Minerals, 1985, 21-25 I.G.M.E. Internal Report, 13 pp. pp.

43. Scott, P.W., 2003. Industrial Minerals: classification, 59. Kaklamanis, N. & Chalkiopoulou, F., 1988. Results of market, geology and exploration. In: D. Eliopoulos et al. beneficiation tests on the weathered granite of Sithonia. (Editors), Mineral Exploration and Sustainable Develop- I.G.M.E., Internal Report, 5 pp. ment, Millpress, Rotterdam, 867-870. 60. Hatzilazaridou, K. & Marantos, I., 2007. Greece is the 44. Skarpelis, N. & Dabitzias, S., 1987. The chrysotile asbes- word. Positive outlook for minerals development. Indus- tos deposit at Zidani, northern Greece. Ofioliti, 12(2), trial Minerals, April issue, 36-41. 403-410. 61. Hatzilazaridou, K., Chalkiopoulou, F. & Grossou, M., 45. Stamatakis, M. & Skounakis, S., 1994. Occurrences of 1998. Greek industrial minerals—Current status and phosphate deposits in the Neogene of basin of Kartero, trends. Industrial Minerals, 369, 45-63. Heraklio, Crete. Bulletin Geological Society of Greece, 30 (3), 341-350.

46. Stamatakis, M. & Tsipoua-Vlachou, M., 1990. Diatoma- ceous rocks in Greece. Minerals, Material and Industry, Proceedings 14th IMM Congress, Edinburgh, Institution Mining & Metallurgy, London, 185-192.

47. Tsirambidis, A.E., 2005. The Mineral Wealth of Greece. Giahoudis, Thessaloniki, 391 pp.

48. Tsirambidis, A.E. & Michailidis, K., 1990. Oxygen isotope evidence on the origin of kaolin deposits of Leucogia Drama, Greece. Geologica Rhodopica, 2, 345-351.

49. Urai, J.L. & Feenstra, A., 2001. Weakening associated with the diaspore-corundum dehydration reaction in me- tabauxites: an example from Naxos (Greece). Journal of Structural Geology, 23, 941-950.

50. Vekios, P., 1979. The rock salt of Monolithi, Ioannina. I.G.M.E. Internal Report, 36 pp.

51. Vekios, P. & Chiotis, E., 1993. Paleogeographic condition formation of phosphates and parent rocks of oil in Hepirus. Contribution to the research of phosphates and hydrocarbons. Bulletin Geological Society of Greece, 28 (2), 535-549.

52. Wetzestein, W., 1975. Hydromagnesit-magnesit- lagerstatten in Macedonien, Nordgrechenland. Mineral- ium Deposita, 10, 129-140.

53. Brellis, G., Grossou-Valta, M., Kalatzis, G., Minopoulos, P., Tsailas, D. & Cohen, H., 1981. Beneficiation of low grade kaolin from Milos island. I.G.M.E., Metallurgical Researches, vol. 31, 29pp.

54. Marantos, I., Karantassi, S., Zachos, S., Romaidis, I., Karmis, P., Chalkiopoulou, F., Kaklamanis, N., Vardakas- tanis, D. & Hiotis, S., 1998. Exploration of the Thermes Graphite. I.G.M.E., Final Report, 14 pp.

55. Kaklamanis, N., 1985. On the results of perlite expanding tests from the Lesvos island. I.G.M.E., Internal report, 14pp.

56. Kaklamanis, N. & Chalkiopoulou, F., 1990. Pilot scale beneficiation tests of the Argos Orestiko Quartz sands. I.G.M.E., Internal Report, 20 pp.

57. Kaklamanis, N. & Chalkiopoulou, F., 1991. Study of Talc

Page 43 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

EVENTS:32nd International Marble Exhibition

MARMIN STONE 2008 (21/2/2008 – 24/2/2008)

International Exhibition Centre HELLEXPO, Thessaloniki

The I.G.M.E. participated in the 32nd International Marble Exhibition (MARMIN STONE) and organ- ised a meeting entitled: RESULTS OF THE CSF III PROJECT OF THE INSTITUTE (2003 – 2008) “Integrated Management of Ornamental Stones, The Deputy Minister, Mr. S. Kalafatis Aggregates and Marbles Extraction Residues— Techniques for the Exploitation of Abandoned Quarries”

The Deputy Minister of the Ministry of Development, Mr. Stavros Kalafatis, opened the Meeting, while representatives of Public Authorities and Marble Sector given short addresses during the opening ceremony. The results of the aforementioned project were presented by the I.G.M.E. sub-project leaders:

1. The I.G.M.E.’s CSF III Project for the Hellenic Ornamental Stones. Results

The General Director of the I.G.M.E., and Benefits for the Quarrying Activity, in Compliance with the Environment. Prof. A.N. Georgakopoulos Dr. Dimitrios Bitzios, Director of the Division of Economic Geology.

2. Management of the Marble Ar- eas of Falakron, Vermion, Ti- saion and Argolida. Results. Dr. Ioannis Chatzipanagis, Geolo-

gist, Regional Branch of Central Macedonia. 3. Colour: The Essential Criterion

Among the Aesthetical Characteristics of Ornamental Stones. The Colour Variations of the Ornamental Stones of the Falakron Mountain. Christos Papatrechas, Geologist, Division of Economic Geology. I.G.M.E.—Exhibition booth 4. Data Base of Aggregates: A Functional Tool for the Qualitative Selection of Aggregate Materials. Dr. Dimitrios Bitzios. Director of the Division of Economic Geology. 5. Ready-Mixed Mortars and Fillers: Markets for the Potential Consumption of the Hellenic Marbles’ Extraction Residues. Fotini Chalkiopoulou, Mineral

Processing Engineer, Division of From Left to Right: Dr. D. Bitzios (I.G.M.E.), Prof. A. Tsirambidis (AUTH), Mineral Processing. Dr. C. Katirtzoglou (I.G.M.E.), Dr. A. Hatzikirkou (I.G.M.E.) 6. Environmental Exploitation of Abandoned Quarries. Contribution to Regional Planning. Dr. Garifal- lia Konstantopoulou, Geologist, Division of Technical Geology, & Eleonora Hagiou, Mining Engi- neer, Division of Feasibility Stud- ies.

The above lectures, in Hellenic, will be accessible via the websites: I.G.M.E. (http://www.igme.gr) MARMIN (http://www.helexpo.gr)

Page 44 Hellenic Geosphaera: Special Issue on Industrial Minerals & Rocks of Hellas

I.G.M.E. ORGANISATION CHART

BOARD OF DIRECTORS

GENERAL DIRECTOR

GENERAL DIRECTOR’S OFFICE DIVISION OF HUMAN RESOURCES [email protected] & ADMINISTRATION [email protected] DIVISION OF INFORMATICS, LIBRARY & PUBLICATIONS LEGAL SUPPORT SERVICES

[email protected] [email protected]

DIVISION OF PLANNING AND DEVELOPMENT INTERNAL AUDITING OFFICE

[email protected] [email protected]

DIVISION OF OCCUPATIONAL DIVISION OF FINANCE SAFETY & HEALTH [email protected] [email protected]

SECTOR OF SECTOR OF BASIC & SECTOR OF WATER SECTOR OF MINERAL SECTOR OF SUPPORTING APPLIED GEOLOGY RESOURCES & RESOURCES & REGIONAL

SERVICES [email protected] ENVIRONMENT EXPLORATION BRANCHES [email protected] [email protected] [email protected]

R.B. OF EASTERN DIV. OF ANALYTICAL DIV. OF ECONOMIC DIV. OF GENERAL DIV. OF MACEDONIA & THRACE LABORATORIES GEOLOGY & GEOLO- GEOLOGY HYDROGEOLOGY [email protected] [email protected] GICAL MAPPING [email protected] [email protected] [email protected] DIV. OF SOLID FUEL R.B. OF CENTRAL DIV. OF RESOURCES MACEDONIA DIV. OF TECHNICAL HYDROLOGY [email protected] SUPPORT [email protected] DIV. OF GEOPHYSICS [email protected] [email protected] [email protected] R.B. OF WESTERN DIV. OF GEOCHEMISTRY DIV. OF MINERAL MACEDONIA & ENVIRONMENT PROCESSING & METALLURGY [email protected] DIV. OF TECHNICAL DIV. OF ENGINEER- [email protected] WORKS ING GEOLOGY [email protected] [email protected] R.B. OF EPIRUS [email protected] DIV. OF GEOTHERMAL DIV. OF MINERALOGY ENERGY & THERMAL- [email protected] & PETROGRAPHY MINERAL WATERS [email protected] [email protected] R.B. OF CRETE

DIV. OF MINING [email protected] DIV. OF MINERAL EXPLORA- ACTIVITIES CONTROL

TION & PROJECT EVALUATION & CONSULTATION R.B. OF [email protected] SERVICES PELOPONISSOS [email protected] [email protected]