March 2008 - IGME · March 2008 Institute of Geology and Mineral Hellenic Geosphaera Exploration (I.G.M.E.) ... Spirou Loui, str. Olympic Village, Entrance C 136 77 Acharnae Tel

March 2008

Institute of Geology and Mineral

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

Newsletter of the Institute of Geology and Mineral Exploration (I.G.M.E.) L.E.P.L. Supervised by the Ministry of Development (L. 272/76) Director General Prof. A. Georgakopoulos Editorial Board: EurGeol Alecos Demetriades Dr. Irene Zananiri Alexandra Zervakou Athanasios Makris Dr. Michalis Patronis Dr. Athanasios Hatzikirkou Editing of this issue:

EurGeol Alecos Demetriades Fotini Chalkiopoulou

I.G.M.E. Central Offices: 1, Spirou Loui, str. Olympic Village, Entrance C 136 77 Acharnae Tel. +30 210 2413000 Fax +30 210 2413015 http://www.igme.gr/ Edition distributed free of charge.

Articles represent the views of the author(s).

Quotation / reproduction is permitted only with proper citation of the source.

Communication: [email protected]

CONTENTS

ISSN: 1791-4523

Introductory address from the General Director of the I.G.M.E.

1

Hellenic industrial minerals and rocks: current research performed by the I.G.M.E., by N. Kaklamanis

2

Potential industrial applications of vein-quartz resources in Northern Hellas, by N. Arvanitidis

7

Applied mineralogy for the efficient exploitation of wasted magnesite Run-Of-Mine fines, by F. Chalkiopoulou, M. Grossou-Valta, S. Karantassi

15

Hellenic marble through the ages: an overview of the marble producing areas and the stone sector of today, by K. Laskaridis

21

The contribution of petrography to the evaluation of carbonate aggregates for concrete production, by M. Dimitroula

27

Radioactivity control of building and decorative materials, by F. Pergamalis, D.E. Karageorgiou, A. Koukoulis, D. Persianis

31

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

35

The modern filler laboratory of I.G.M.E. 6

Mineralogical - Petrographical laboratories 14

“LITHOS”: The accredited ornamental stone quality control laboratory of the I.G.M.E.

20

MARMIN STONE 2008 44

H 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 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 inno-vations 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 informa-tion on deposits of industrial minerals and rocks;

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

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

I N T R O D U C T O R Y A D D R E S S F R O M T H E I N T R O D U C T O R Y A D D R E S S F R O M T H E G E N E R A L D I R E C T O R O F T H E I N S T I T U T E G E N E R A L D I R E C T O R O F T H E I N S T I T U T E

O F G E O L O G Y A N D M I N E R A L E X P L O R A T I O NO F G E O L O G Y A N D M I N E R A L E X P L O R A T I O N

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

Nikos Kaklamanis Mining Engineer ([email protected])

I.G.M.E., Division of Mineral Processing

Currently, the research carried out by the I.G.M.E., for the location and evaluation of Hellenic Industrial Min-erals and Rocks is included in the project entitled “Industrial Minerals – Innovative Technologies – New Products”, funded by the Community Support Framework III, Operational Programme “Competitiveness”. The project, with a total budget of 1.1 million Euros, has the following prin-cipal objectives:

• Rational exploitation of mineral resources via the development of environmentally friendly tech-nologies/methodologies for the utilisation of Industrial Minerals, by-products and wastes.

• Reinforcement of the local indus-tries’ competitiveness by improv-ing production procedures, elimi-nating production costs and pro-moting new high-added value commercial product types.

• Development of new products, new markets and new fields of applications.

• Utilisation of by-products and wastes in order to produce low-cost raw materials.

• Utilisation of Industrial Minerals in environmental applications, in-cluding elimination of environ-mental impacts.

• Design and development of a G.I.S. Data Base for the Hellenic

Industrial Minerals, not only the ones examined currently, but also those studied in the past by the I.G.M.E.

The project is subdivided into ten separate sub-projects, each one covering a specific industrial mineral commodity of Hellas, and specifi-cally: (a) Feldspars, (b) Quartz, (c) Zeolites, (d) Vermiculite, (e) Oli-vinites, (f) Garnet, (g) Industrial Minerals for cement industries, (h) Clays, (i) White Carbonates, and (j) Fly-ash. As mentioned above, all project results will be included in a Data Base, which shall also incorpo-rate all relevant data concerning Hellenic Industrial Minerals & Rocks.

In addition, three activities—tasks, namely (a) a G.I.S. data base for Hellenic Industrial Minerals, (b) ap-plication tests regarding the use of Industrial Minerals for the neutrali-sation of effluents, and (c) study of zeolite-vermiculite ash as a soil im-prover, were subcontracted and im-plemented by private companies, which are supporting the research activities undertaken by the I.G.M.E. within the aforementioned sub-projects.

In the following paragraphs, the main objectives and work carried out in each sub-project are concisely discussed. The major exploration

1. 1. FRAMEWORK AND OBJECTIVES FRAMEWORK AND OBJECTIVES

H E L L E N I C I N D U S T R I A L M I N E R A L S A N D H E L L E N I C I N D U S T R I A L M I N E R A L S A N D

R O C K S : C U R R E N T R E S E A R C H P E R F O R M E D R O C K S : C U R R E N T R E S E A R C H P E R F O R M E D

B Y T H E I . G . M . E . B Y T H E I . G . M . E .

Current Industrial Mineral Research

Operational Programme “Competitiveness”

Support Framework III


and research sites, covered by the project are presented schematically on the map of Figure 1.

2. 2. BRIEF DESCRIPTION OF BRIEF DESCRIPTION OF SUBSUB--PROJECTSPROJECTS

2.1. Feldspars

This sub-project aims to contribute to the devel-opment of innovative and environmentally friendly technologies for mineral processing of feldspathic raw materials. The proposed tech-nologies will be applied on different important types of Hellenic deposits, such as pegmatites, tuffs, rhyolites and granites, in order to evalu-ate the feasibility and technical efficiency of corresponding cases, for the production of high grade and high added value commercial prod-ucts with parallel elimination of environmental impacts. Major tasks of the project were: (a) geological mapping of an area of 6 km2 (scale 1:5,000) and a second of 0.1 km2 (scale 1:200), (b) collection of 150 samples, (c) labo-ratory measurement and testing, comprising mainly magnetic separation and flotation test work, (d) collection of 5 bulk samples, each of 1 tonne weight, (e) pilot plant test work, and fi-nally (f) market research.

2.2. Quartz

The aim of the sub-project is to develop benefi-

ciation methods for the treatment of high purity

vein quartz reserves from Northern Hellas, in

order to produce ultra–pure grades of quartz.

The specific research focuses on extracting low–

sodium quartz deposits and developing new

technologies for efficient removal of fluid inclu-

sions, which contain a relatively high percent-

age proportion of sodium. The following tasks

have been completed within this project, to

date: (a) geological mapping of an area of 19.5

km2 (scales 1:20,000, 1:10,000 and 1:5,000)

and a second of 1 km2 (scales 1:1,000, 1:500

and 1:200), (b) collection of 190 hand samples,

representing 31 research areas in Central and

Northern Hellas, (c) laboratory test-work, com-

prising mainly magnetic separation of composite

samples and acid treatment, as well as calcina-

tion tests on non- magnetic products, (d) collec-

tion of two bulk samples, each of 20 tonnes

weight, and finally (e) pilot plant test-work.

2.3. Zeolites

The research is carried out in Thrace (Northern Hellas, Rhodope and Evros Prefectures) and the Prefectures of Arkadia and Lakonia in Pelopon-nesus. The aim of this sub-project is to evaluate the natural zeolite deposits, occurring in the aforementioned areas, in terms of their techni-cal and economic feasibility for the production of materials appropriate for (a) the treatment- purification of potable water, (b) treatment of liquid effluents for removal of heavy metal (such as Pb, Cd, Cu, Cr, Ni), (c) improvement of soil in combination with other raw materials, such as fly ash and vermiculite. The research performed to date included the following:

• Geological mapping of an area of 3 km2 (scale 1:5,000), a second of 10 km2 (scale 1:5.000) and a third of 32 km2 (scale 1:50.000) at Petrota (Evros Prefecture, Thrace, N.E. Hellas), as well as compilation of geological sections of 30 km total length,

• Collection of 100 hand samples of zeolite for laboratory research and mainly the measure-ment of their ion exchange capacity,

• Compilation of an inventory of 400 fountain-head sites, and collection of 400 water sam-ples located in the Peloponnesus area.

• Collection of a composite bulk sample of about 15 m3 that was mainly used for testing in different agricultural applications.

2.4. Vermiculite

Within the framework of this sub-project, re-search work was undertaken in Central Mace-donia, Northern Hellas, in order to evaluate known serpentinite bodies for their vermiculite potential. Furthermore, samples of raw and ex-panded vermiculite were tested as effluent processors and in agricultural applications. Briefly, the tasks accomplished comprise (a)

CURRENT RESEARCH ON INDUSTRIAL MINERALSCURRENT RESEARCH ON INDUSTRIAL MINERALSCURRENT RESEARCH ON INDUSTRIAL MINERALS


geological mapping of an area of 1 km2 (scale 1:5,000), (b) collection of hand and bulk sam-ples, (c) expansion test work on the bulk sample, (d) application tests by using the expanded ver-miculite firstly to achieve the growth of high val-ued crops, and secondly in greenhouse and hy-droponica l ly grown plants. Finally, raw, as well as expanded ver-miculite, were tested for their appropriateness in environmental applica-tions, and specifically for the removal of heavy metal from industrial ef-fluents (plating and tan-ning industries), as well as the improvement of potable water supplies.

2.5. Olivinites

The main objective was to evaluate the olivinite potential of dunite/hartzburgite bodies in the Vavdos and Vourinos areas (Chalkidiki and Grevena Prefectures re-spectively), as sources for the production of high quality olivine sand for castings, other than Mn-steels, and as an abrasive. The work accom-plished to date included the following:

i) Geological mapping of an area of 2 km2 (scale 1:5,000). The mapping concerned the Vavdos Public Mine and the Chromio village area;

ii) Eight drill-holes of 450 m total length in the Vavdos and Vourinos areas to esti-mate the size of the corresponding depos-its;

iii) Collection of hand samples and a 13 ton-

nes bulk sample from the Vavdos Public Mine.

The bulk sample was subject to pilot crushing and screening for the production of grades, ap-propriate to industrial testing in the above men-tioned applications, with hitherto positive re-sults.

2.6. Garnet

Limited research has been accomplished within this sub-project, covering mainly economic ge-ology aspects, and more specifically statistical evaluation of garnet occurrences in the areas of


Crete

Yali

ATHENS

Kefallonia

Zakynthos

Chalkidiki

Drama

Larissa

LEGEND Pozzolana Olivinite Zeolite Feldspar Garnet Clays Quartz Calcium Carbonates (Filler grade) Vermiculite Fly ash

Kavala

Veria

N

100 km

Milos

Figure 1. Schematic presentation of the current investigation sites for Industrial Minerals and Rocks in Hellas.


Svoula in the Chalkidiki Prefecture, as well as validation exploration research on Serifos Island in the Aegean Sea.

2.7. Industrial Minerals for the Cement Industry

The research conducted was initially focused on the location of pozzolanas in the areas of East-ern Macedonia and Thrace, Central Macedonia, as well as on Crete Island. Finally, it was re-stricted in Central Macedonia, where geological mapping was carried out on an area of 10 km2 and a hundred samples collected for examina-tion of mainly their pozzolanity.

2.8. Clays

The aim of the specific sub-project was the lo-cation of clay mineral deposits to be used in the ceramic industry, and as land fillings in waste disposal sites. The tasks performed covered the broader areas of Central Macedonia (Northern Hellas), Epirus (N.E. Hellas), Thessaly (Central Hellas), and Peloponnesus (Southern Hellas) and included the following work (a) Geological mapping of an area of 80 km2 (scale 1:50,000), (b) collection of 480 hand samples, (c) evalua-tion of the characteristic features or each sam-ple, (d) collection of bulk samples, (e) industrial testing of bulk samples in ceramic factories, and (f) selection of the most interesting areas to be studied on a pilot scale.

2.9. White Carbonates

The research aims to locate resources of white carbonate materials of an appropriate quality for the requirements of the Chemical Industry (paints, paper, plastics). Although areas such as the Ionian Islands of Lefkada and Zakynthos were initially included in the project, two areas were finally studied: (a) the Vermion Mountain in Imathia Prefecture (Northern Hellas), and (b) Crete Island (Southern Hellas). Geological map-ping was carried out over a total area of about of 125 km2 (1:20,000) in both areas studied. The collected 125 samples were subject to labo-ratory measurements and testing. For the high quality specifications of raw materials (high cal-

cium carbonate content and high whiteness measurements) additional tasks were per-formed in the studied areas, including geological mapping and estimation of reserves.

2.10. Fly Ash

Although fly ash does not comply with the geo-logical definition of “Industrial Mineral” (a natu-rally occurring substance), it was included in this project as a research theme, mainly due to its potential industrial applications. The aim is to develop environmentally friendly methodolo-gies for exploitation of fly-ash, as well as bot-tom-ash, produced from the lignite electric power generation plants, as soil-improvers in agricultural applications. Within the project, an inventory of the fly- and bottom-ash wastes was compiled, providing thus relevant data for the electric power plants of Ptolemaida and Amindeo in Northern Hellas, and Megalopolis in Peloponnesus in Southern Hellas. In total, 220 fly ash and 25 bottom ash samples were col-lected. Bulk samples were also taken in this sub-project; 50 fly-ash samples of 50 tonnes each, and 10 bottom-ash samples of 12 tonnes each. Hand samples underwent extensive labo-ratory studies, while bulk samples were tested as soil improvers for agricultural purposes, as well as neutralisation of acid soil.

3.3. FUTURE WORKFUTURE WORK

All the aforementioned sub-projects are near to completion, given that they are funded by the Community Support Framework III Programme, with a deadline at the end of this year. At the current stage, interim reports are being pre-pared and submitted. Accordingly, the final technical reports are to be completed by the end of the year. The project’s major results will be communicated to the relevant authorities, according to the rules of the Operational Pro-gramme “Competitiveness”.



Figure 1. Partial view of the Filler Laboratory. 1c

1a

1b

1a: Spectrophotometer, VARIAN CARY 100

1b: Particle Size Analyser, SEDIGRAPH

1c: Porosity, BET Surface Area, QUANTACHROME

1d: Air Jet Sieve, ALPINE

1e: Abrasion Tester, AT 1000, EINLEHNER

1f: Colour Meter, LFM1 Dr LANGE

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-ern machinery and apparatus (Figs. 1-3), which, in con-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.

Besides simple meas-urements & testing of materials, in-tegrated studies for the exploita-tion of Mineral Raw Materials in the field of Fillers are feasible. 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 Growth”, with a budget of 285 thousand Euros. This pro-ject 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.

T H E M O D E R N F I L L E R L A B O R A T O R Y T H E M O D E R N F I L L E R L A B O R A T O R Y

O F T H E I N S T I T U T EO F T H E I N S T I T U T E

DIVISION OF MINERAL PROCESSING ([email protected])

Figure 1 1e

1d 1f

1c

Figure 2. Laser Diffraction, Particle

Size Analyser, CILAS 1064.

Figure 3. Jet Mill.

• Field hand/bulk sampling, crushing, grinding & sieving

• Ultra fine (d97<5μm) grinding by jet milling

• Evaluation of Optical Properties (X, Y , Z, Rx, Ry, Rz, L*, a*, b*) [ASTM C-110-06, E313 / DIN 6174]

• Abrasion Measurement, EINLEHNER

• Particle Size Analysis of Powders: Laser Diffrac-tion, Sedigraph, N. Stokes [0.1 μm—500 μm]

• Porosity and BET Surface Area Measurements

• Evaluation of Carbonate Raw Materials accord-ing to EN ISO 3262.05 & EN ISO 3262.07


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

ΠερίληψηΠερίληψη

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.

AbstractAbstract

Northern Hellas hosts a number of strategic Industrial Minerals, which make it an increasingly 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. Among the marketable end products a pure white variety is exported for polyester tile manu-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 conven-tional 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 re-moval of fluid inclusions for reducing the high sodium impurities. Innovative beneficiation tech-niques were developed to produce optical and electronic grade quartz. The high content of so-dium, 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 fur-nace. The quality grades achieved to date, may already place the Hellenic quartz in a good po-sition 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 mar-ketable products and industrial applications.

P O T E N T I A L I N D U S T R I A L A P P L I C A T I O N S P O T E N T I A L I N D U S T R I A L A P P L I C A T I O N S

O F V E I NO F V E I N -- Q U A R T Z R E S O U R C E S Q U A R T Z R E S O U R C E S

I N N O R T H E R N H E L L A S I N N O R T H E R N H E L L A S

Quartz Veins

High Purity Quartz Grades

New Industrial Applications


1.1. INTRODUCTIONINTRODUCTION

The main research and development activities on quartz, worldwide, concern today its applica-tion in the production of microelectronic compo-nents, semiconductors, etc. The production of ultra-pure quartz, for the electronic and optical industries, has a strong future in Europe. For the next few years, a drastic increase in de-mand of ultra-pure quartz/silicon is expected for a number of high-tech applications, such as halogen bulbs, photovoltaic systems, high den-sity integrated circuits, laser lenses, silica foam, optical fibres. The sole producer of ultra pure silicon in the world is located in N. Carolina (U.S.A.), and supplies the U.S.A., the Japanese and the European markets. The development of a new European industry for the production of ultra to high purity quartz will increase the com-petition in the world market and eradicate the hitherto U.S.A. monopoly conditions.

2. 2. THE RESEARCH ACTIVITIES OF THE THE RESEARCH ACTIVITIES OF THE I.G.M.E. ON QUARTZ I.G.M.E. ON QUARTZ

Exploration for vein-quartz deposits, as well as

project, the achieved quartz qualities, in terms of elemental chemical impurities (Fe, Al, Ti, Na and K), appear feasible for the optics industry. Two follow-up projects, financed by the Euro-pean Structural Funds Programme, aimed to achieve further quartz upgrading, and new fields of industrial application.

3. 3. VEIN GEOMETRY, MINERALOGY, VEIN GEOMETRY, MINERALOGY, DEFORMATION AND CHEMISTRY DEFORMATION AND CHEMISTRY

3.1.3.1. GeneralGeneral

According to findings of the regional scale min-eral exploration, accomplished within national and EU–funded projects, the Northern Hellas mainland hosts numerous vein-quartz deposits. Figure 1 shows the locations of discovered and known veins hosted by rocks belonging to the Serbomacedonian (SMZ), Pelagonian (PZ) and Rhodope (RZ) geotectonic zones. Quartz veins routinely occur in two-mica and biotite gneiss, occupying extensional fractures, except for rare cases where they partly transect granite bodies. They form disrupted and boudinaged steeply

INDUSTRIAL APPLICATIONS OF VEININDUSTRIAL APPLICATIONS OF VEININDUSTRIAL APPLICATIONS OF VEIN---QUARTZQUARTZQUARTZ

Figure 1. Simplified geological setting of vein-quartz deposits in Northern Hellas.

QUARTZ DEPOSITS AND MINING IN HELLAS

Quartz Veins

Quartz-Feldspar Pegmatites

Quarries

Mineral Processing Mill

Mine Wastes/By-products

BULGARIA

RHODOPE ZONE

SERBOMACEDONIAN ZONE

CIRCUM RHODOPE BELT

PAIKO ZONE

ALMOPIA ZONE

PELAGONIAN ZONE

evaluation of known pros-pec t s , i n No r the rn (Macedonia, Thrace) and Central (Thessaly) Hellas, has been carried out by the I.G.M.E. within the frame-work of a Brite–EuRam II Programme project entitled “New Industrial Applica-tions for Quartz Deposits Indigenous to the Commu-nity” (BRE2-CT94-1026) (period 1995-1998). The project aimed to develop advanced beneficiation techniques to produce ul-tra-pure quartz/silicon for high-tech application needs of the European market, using Hellenic vein-quartz as raw material. Along with the completion of the


dipping (90o to 40o) bodies, striking NNW-SSE, concordant to regional schistosity. Veins meas-ure from 30 up to 100 m in length, rarely reach 300 or 500 m; thickness varies from 3 to 15 m. Veins are composed chiefly of milky (Fig. 2) or yellowish-brown quartz (up to 99.5% by vol-ume) with traces of white mica, sulphides, feld-spar and iron oxides.

The quartz grains are deformed, subhedral to anhedral, elongated and slightly oriented, with relative dimensions of up to 8 mm along their longest axis and up to 4 mm in width. Vein- quartz has suffered (a) an early episode of duc-tile deformation (quartz 1), postdating the vein

filling, attributed to emplacement of veins in a dynamic, tectonically active, environment; (b) brittle fracturing that took place after the ductile deformation, accompanied by cataclasis and re-crystallisation (quartz 2).

Serbomacedonian raw quartz chemical composi-tion shows ranges of Fe=1-28 ppm, Al=22-73 ppm, Na=12-37 ppm, K=4-28 ppm, Ca=11-40 ppm, Mg=4-10 ppm, Ti=1.4-4.8 ppm and Li=0.1-0.9 ppm. The problem, for electronic high-tech applications of quartz, arises from high Na contents, which is the most difficult ele-ment to degrade to quality requirements by the

purification techniques, used to success-fully eliminate other elements (i.e., Fe,

Al, Ca, Ti).

Chemical removal of fluid inclu-sions, and subsequent degradation to 2.9 ppm Na, resulted to substan-

tial quality improvement of quartz (Table 1). However, after a specific,

contamination free comminution, and a first screening by XRF analysis of lump quartz sam-ples, undertaken by Dorfner ANZAPLAN, the fol-lowing results were obtained: 0.01 wt% Al2O3, <0.005 wt% Fe2O3, <0.002 wt% TiO2, and K2O, Na2O, CaO, MgO were all <0.01 wt%. Due to the fact that most elements are below the XRF detection limits, these quartz sources seem highly potential for high purity applications.


b

a

Figure 2. Milky quartz veins hosted by SMZ Gneiss, Kilkis Prefecture, Central

Macedonia, Northern Hellas.

(a) Milky quartz vein exposure in the Vertiskos Formation Gneiss;

(b) Semi-transparent quartz with minor iron staining.

1 2 3 4 5

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

6

ele

men

t

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

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


3.2.3.2. Fluid InclusionsFluid Inclusions

Fluid inclusion-hosted, as well as structurally-bound (Fig. 3), trace elements were determined in hydrothermal-metamorphosed vein-quartz from N. Hellas, using Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) as a screening technique of possible ultra pure quartz resources.

The main objective of these determinations was to test whether the elemental “impurities”, in terms of commercial value, recorded by bulk chemical analysis of quartz, were due to the presence of aqueous fluid inclusions or micro-mineral impurities. Fluid inclusions have proved to be the principal hosts of Na and Sr “impurities”, and possible controllers of Mg, Ti and Ca abundance (Table 1).

These results confirm the estimated composi-tion of fracture-controlled aqueous fluid inclu-sions, derived from microthermometric meas-urements, which preceded LA-ICP-MS analysis. The inclusions were characterised by high levels of Na (5000-2000 ppm), Sr (26 ppm) and Li (45 ppm), compared to the quartz matrix (Na 100-600 ppm, Sr<2 ppm, Li<1 ppm). Ablation runs, along an array or zone of inclusions, have shown Na values of up to 6000 ppm and Sr up to 37 ppm. Titanium is generally <2 ppm, and Mg levels less than 10-20 ppm, in the quartz matrix. The highest levels of Ti (6-12 ppm), Mg

(30–1600 ppm), and Ca (up to 5500 ppm) are associated with zones of fluid inclusions. Excess Al is more likely due to the ablation of discrete sub-micron clay or mica impurities, trapped along the healed micro-fractures.

The anomalous levels of Fe may be due to min-eral impurities (possibly sulphides), trapped along micro-fractures. The laser ablation ICP-MS analysis, conducted in the present study,

resulted in the as-sessment of qual-ity and industrial classification of vein-quartz, and the application of suitable benefici-ation techniques able to remove elemental impuri-ties (e.g., chemi-cal removal of fluid inclusions), and to produce ultra-pure grades.

Mineral processing studies were focused on beneficiation of quartz tailings samples to con-vert them into exploitable resources and com-mercial products, as well as beneficiation tests on vein-quartz samples. A flow-chart including crushing, classification, grinding, attrition treat-ment, drying and magnetic separation was de-veloped, to improve the stages of a processing plant already in successful operation.

In terms of quartz tailings beneficiation, white-ness, iron content and mineral impurities re-moval, which are considered to be important for a number of construction materials and metal-lurgical applications, were already attained by pilot plant testing.

Processing tests on vein-quartz samples, in-cluded crushing, screening, magnetic separa-tion, as well as acid washing and calcination of non-magnetic fractions, to achieve substantial upgrading of final products. Several kilograms of these samples were subjected to further puri-


(a) Dense network of sub-parallel closely spaced quasi-linear to curved secondary fluid inclusion trails along cross-cutting healed

(b) Intragranular secondary fluid inclusion trails of healed micro fractures affect-ing the quartz matrix.

Figure 3.


fication processing.

All mineral processing lines tested, were co-evaluated to further develop a working flow-sheet for potential beneficiation of represen-tative vein-quartz samples.

Laboratory and pilot-plant trials were com-bined to define the optimum industrial scale flow-sheet. At the same time, beneficiation testing of quartz, undertaken by available, and currently operating techniques of indus-trial ultra-pure quartz manufacturers, re-duced iron content to 0.15 ppm; a fact which has a potential value for new industrial uses. However, the problem for electronic high-tech applications of quartz arisen from the high Na, and not Fe, content. It is obvious that low-alkali grades of quartz veins cannot be discovered, and beneficiation was focused on the removal of fluid inclusions.

Further, removal testing of the <4 to 200 μm fluid inclusions, and other minute mineral im-purities, was undertaken by statistical tech-niques, such as mathematical morphology evaluation, as for example, the probability of existence or not of an inclusion in a certain micro-distance from another.

For this purpose, carefully selected and field oriented quartz samples were taken, double-polished thin-sections prepared and detailed fluid inclusions studies, including cluster den-sity, morphology evaluation and microphotog-raphy were carried out.

The statistical methodology, was combined with grinding systems, grain-size distribution, solid-solid separation techniques, flotation, magnetic and electrostatic separation and leaching to produce ultra-pure quartz grades. During this process (application of statistical and beneficiation techniques), three different qualities of final products were obtained, named quartz-2, quartz-1 and ultra-pure quartz. The problem with these purified prod-ucts is not the quality that is well within the optical glass quartz specifications, but the granulometry (<30 μm), which is well below

the required range (70-300 μm).

3.3.3.3. Plasma smelting pilotPlasma smelting pilot--plant plant construction construction

Theoretical modelling of the plasma furnace conditions was carried out in order to design the plasma technology processing line. A twin reactor with two power supplies and graphite lining was designed and constructed. The plasma furnace, to reduce heat conduction losses, consists of two graphite crucibles and zirconia pieces, and a ceramic felt, and is fed by alumina slag. The operating temperature is about 2,300oC in the furnace, and about 2,050oC at the top of the burden. Reduction of quartz (after the addition of pure iron) led to the production of ferrosilicon and mixed iron and silicon carbides. Work, on characteri-sation of the quality grade of commercial ferrosilicon, was undertaken to assess its foundry applicability. Heat Resistant Steels and Grey-Iron Castings were produced.

3.4.3.4. Market Research Market Research

The main industrial specifications, in terms of element contamination (mainly iron, alumina, titanium and alkalies), fluid inclusion distribu-tion and granulation, for obtaining ultra-pure quartz grades were established. At the same time a significant number of major European markets of quartz were identified and related to realistic applications for Hellenic quartz.

Market research already started in the first year to consider the required quartz specifi-cations for specific high-tech applications, and to open the project’s general vision in terms of industrial exploitation. It was discov-ered that the requirements needed in semi-conductor and/or long-range optical fibre ap-plications, as far as Al and Ti contents are concerned, cannot be reached with the pre-sent technology, without dissolving the quartz itself, in any natural quartz mined today at any quantity.

For semiconductor applications the alkalies are particularly important, with Na and Ca contents of Hellenic raw quartz being somewhat high.



Other end-users require specifications of (Li+Na+K) <1 ppm.

On the other hand, a specific European indus-try requires less strict quality specifications of silica flour for optical glass production, with a current consumption of 600 tonnes per an-num (tpa). In the framework of the project, a number of quartz grades for various applica-tions and related prices, were determined. In terms of exploitation, the project objectives were disseminated through contacts with in-dustrial end-users and conference presenta-tions.

The mineral exploration already conducted, located feasible vein-quartz deposits, which require further investigation, mainly with re-spect to quality characterisation. The quartz producing industry in Hellas faces today seri-ous problems of lack of resources and, also, new technology possibilities for product up-grading and market expansion.

The market research and analysis under-taken, 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 mi-cronised quartz (<10 μm), a reasonable esti-mate for the total amount required is about 5,000 tpa. It makes a high added value prod-uct, 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 effec-tive 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 con-struction applications. Of course, the achieve-ment of optical grade end-products remains a strong potential opportunity of the Hellenic quartz industry.

4.4. CONCLUSIONSCONCLUSIONS

Significant reserves of quartz of variable quality have been located that guarantee con-tinuity of product supply to industry over a period of tens of years. Beneficiation testing resulted in obvious quartz quality improve-ment. The main techniques required for fur-ther purification, e.g., removal of fluid inclu-sions and trace element impurities, have been identified and experimentally developed. In addition, the flow-chart for beneficiating and converting quartz tailings to commercial products was industrially elaborated.

A market research of the variably purified and upgraded quartz powders, for a number of industrial applications, has been systemati-cally initiated. Finally, the plasma furnace, coupled by quartz fines melting, and the ferrosilicon and silicon metal production, has been designed and constructed.




PARTNERSHIP - ROLE OF PARTNERS:

• The Institute of Geology and Mineral Exploration

(I.G.M.E.), serving as project leader, coordinated the joint research. Also, it contributed with all available mineral exploration data, and provided quartz sam-ples for analyses and testing.

• The Hellenic Industrial Minerals S.A. (ELVIOR), the

main quartz exploitation and development company in Hellas, expanded its processing plant capacity in order to introduce an ultra-pure quartz production line.

• The Metallurgical Industrial Research and Technologi-

cal Development Centre S.A. (MIRTEC), equipped with pilot plasma furnace, applied the plasma technol-ogy to produce silicon metal and ferro-silicon with low impurities content.

• Tetronics R&D Company Ltd., a high-tech manufac-

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 interna-tional 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.

PROJECT BRE2-CT94-1026:

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

I.G.M.E.:

SCIENTIFIC STAFF INVOLVED IN THE PROJECT

• Regional Unit of Central Macedonia:

A. Theodoroudis, N. Veranis, N. Apostolou, P. Tsamantouridis, C. Papadopoulos, K. Katsiavalos,

S. Kilias (presently at Athens University)

• Division of Mineral Processing:

Μ. Grossou, N. Kaklamanis, V. Angelatou, P. Chara-lampidis, F. Chalkiopoulou, I. Mavrogiannis

• Division of Mineral Economic Evaluation:

I. Drougas, V. Pefani.

• Division of Geophysics: G. Skianis

• Division of Mineralogy and Petrography:

V. Perdikatsis (presently at the Τechnical University of Crete), S. Karantassi, G. Economou


The Division of Mineralogy and Petrography in terms of its multiple activities on mineralogical and

petrological studies of geological, mining, environ-

mental, hydrogeological and other research, is ac-

tively involved in the research of industrial minerals

and rocks, i.e., Zeolites, Quartz, Clays, Garnets,

Marbles, etc.

More specifically, it is carrying out specialised laboratory de-terminations and analyses, with state-of-the-art high tech-nology 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 labora-tories for making thin and polished thin sections etc.

M I N E R A L O G I C A LM I N E R A L O G I C A L -- P E T R O G R A P H I C A L P E T R O G R A P H I C A L

L A B O R A T O R I E S L A B O R A T O R I E S

DIVISION OF MINERALOGY & PETROGRAPHY ([email protected])

The analytical techniques used are:

• Light microscopy

• Scanning Electron Microscopy (Fig. 1)

• X-Ray Diffraction

• Micro-Raman Spectroscopy (both portable and desk in-strument) (Fig. 2)

• Differential Thermal Analysis

Figure 2. Raman.

Figure 1b. SEM Photographs.

Figure 1a. Scanning Electron Microscope (SEM).


AbstractAbstract

Applied mineralogy is a key tool for the process engineer, from the very early stage of field research up to the final of decision making for processing of a mineral raw material. This was 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 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 Thermal Analysis, X-Ray diffraction and Electron Probe Analysis. Detailed work was done at the beginning of the project in order to identify the different mineral constituents of the material under investigation. Mineralogy supported the evaluation/selection of processing methods/ techniques, and design of a generic flow diagram. Alternative magnetic separation and heavy media separation techniques were tested. The innovation was the exclusive development of a new Reticon Camera Sorter for project needs. Non-magnetic drums were also used in an inno-vative way for ‘screening’ the material. Simulation tools were also used for optimisation of the process flow-sheet, based on an ore model, developed specifically for the project. In conclu-sion, 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.

The MAGFINES Project

Processing of Magnesite Run-Of-Mine Fines

Mineralogy—Petrography of Magnesite

Ore Model of Magnesite for Simulation

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


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.

A P P L I E D M I N E R A L O G Y A P P L I E D M I N E R A L O G Y

F O R T H E E F F I C I E N T E X P L O I T A T I O N O F F O R T H E E F F I C I E N T E X P L O I T A T I O N O F

W A S T E D M A G N E S I T E R U NW A S T E D M A G N E S I T E R U N -- O FO F -- M I N E F I N E S M I N E F I N E S


EXPLOITATION OF MAGNESITE RUNEXPLOITATION OF MAGNESITE RUNEXPLOITATION OF MAGNESITE RUN---OFOFOF---MINE FINESMINE FINESMINE FINES

1. 1. INTRODUCTION INTRODUCTION

The case examined in this paper concerns the Brite EuRam project “New Process Routes for the Recovery of Magnesite Run-of–Mine Fines (BRE2-CT92-0388)”, with the acronym MAGFI-NES, co-ordinated by Grecian Magnesite S.A. with partners the Institute of Geology & Mineral Exploration, Hellas, and Control International S.A., France. The aim of the project was to de-velop a new procedure for the potential exploi-tation of industrial mineral fines (<12 mm), be-ing the waste from a previous treatment. The focus was on Hellenic magnesite Run-Of-Mine (R.O.M.) fines in order to increase the magne-site production capacity at a low cost, to reduce the waste disposal area requirements, and thus to slow down the depletion of natural mineral wealth. Major and complex problems were ad-dressed during project implementation that con-cerned the nature and physical properties of materials under investigation. The answers to these problems were crucial for process selec-tion, and the efficiency of the separate meth-ods/techniques applied.

2. 2. IDENTITY OF THE MATERIALIDENTITY OF THE MATERIAL

2.1. Methods

Extensive work was carried out at the beginning of the project2,3,7 on samples representing vari-ous stockpiled materials and current (at that time) R.O.M. fines. The laboratory methods em-ployed 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-ogy (Table 1), and the main minerals are mag-nesite, serpentine and quartz. Their mode of

occurrence is common to all samples and size fractions studied, and their percentage propor-tions show only slight differences from sample to sample and from size fraction to size fraction.

Table 1. Mineral constituents of R.O.M. fines

Magnesite (Fig.1) occurs in pure or composite grains, is cryptocrystalline and found in two grain sizes. The finer grains (a-Mg) are <5 μm, while the coarser ones range from 5 to 10 μm (β-Mg). The cryptocrystalline texture of magne-site is, in general, a favourable factor for its molecular purity.

Figure 1. Pure cryptocrystalline magnesite (Mg) aggregate (Transmitted light, +Nicols, x166).

Serpentine representing serpentinite is the prin-

Magnesite MgCO3

Olivine (SiO4)(Fe,Mg)2

Enstatite (Si2O6)(Mg,Fe)2

Chromite (FeII,Mg)(Cr, Al, FeIII)2O4

Serpentine (Si2O5)Mg3(OH)4

Magnetite Fe3O4

Tremolite Ca2Mg[(OH)2Si8O22)]

Phyllosilicates KMg3[(OH),F)2AlSi3O10

Chlorite Mg5(Al,Fe)(OH)8(Al,Si)4O4

Talc Mg3(OH)2(SiO5)2

Dolomite (Mg,Ca)CO3

Calcite CaCO3

Quartz SiO2 (chalcedony, opal)

Iron Hydroxides FeO(OH) (goethite)

Mineral Formula



cipal mineral of the petrological environment of magnesite, and is the most widespread phase in gangue material. It occurs in high percentage proportions in all samples, regardless of grain size, and occurs in foliated (antigorite-lizardite), fibrous (chrysotile) and cryprocrystalline (serpophyte) forms (Fig. 2). The high iron hy-droxide content in several serpentine grains in iron hydroxides facilitates their removal by magnetic separation.

Figure 2. Composite fragments of magnesite (Mg), talc (Tc), serpentine (Srp), pyroxene (Py) in various combinations

(Transmitted light, +Nicols, x66).

Quartz–Chalcedony–Opal: Grains of mostly quartz, but also chalcedony and rarely opal, oc-cur in all size fractions of the samples studied. The close association of magnesite-silicates, as observed partly in some grains (Fig. 3), makes their complete separation difficult, in addition to the lack of magnetic susceptibility of both mate-rials and their similar colours.

Figure 3. Composite magnesite (Mg) and quartz (Q) grains in various proportions (Transmitted light, +Nicols, x42).

It is expected that, where there is strong adhe-sion between magnesite and silicates, especially in the case of cryptocrystalline (chalcedony) and amorphous (opal) varieties, the effort to sepa-rate and remove them will not give satisfactory results. Part of the quartzitic material contained in the fines is rich in iron hydroxides, and can be removed 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 impor-tant 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 as-sociation with magnesite, are so variable that their complete separation is apparently very dif-ficult. It is estimated that, application of some processing procedures will result, either in mag-nesite "losses" (removal of composite grains with gangue), or in low quality final products (due to presence of composite grains). These impurities create various qualitative and quanti-tative combinations in the particular magnesite grains, resulting in the so-called multi-composite fragments. It should also be made clear that the quantitative participation of mag-nesite in this class of material is variable, and is 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. 3. CONTRIBUTION OF MINERALOGY CONTRIBUTION OF MINERALOGY DURING PROCESSINGDURING PROCESSING

3.1. F.I.S. Test-Work

The objective of the processing test work was to decide on the selection of the most appropriate



combination of methods/techniques for efficient and economic production of commercial grades of raw magnesite, namely products with a mini-mum MgCO3 content higher than 80%. For this purpose, a series of laboratory and pilot scale tests were performed. Orientation tests were initially carried out with a Frantz Isodynamic Separator (F.I.S.). A number of samples were magnetically separated with F.I.S. in order to evaluate the relative susceptibility of the vari-ous grains of the different minerals.4,5 The com-position of magnetic and non magnetic products was studied in detail by Optical Methods. These data and information were very important for the development of the ore model that was used for process simulation.

3.3. Mineralogical Examinations During Laboratory Process Testing

The overall research was oriented towards the R.O.M. wastes’ processing that could be easily incorporated in the existing mill of Grecian Mag-nesite (GM) and methods such as flotation was not considered at all, since optical separation and heavy media treatment were the proce-dures already installed. The lower limit for proc-essing had been so far the 12 mm, which ex-plains the stockpiling of the <12 mm ROM ma-terial. GM was the first company to attempt the design of a sorter for the treatment of 5-12 mm material. The development of this new Sorter was achieved within the project. This machine is using Reticon Camera technology rather than lasers, as in existing models that are processing >12 mm materials.1 Further to testing on the specific sorter, there was work on: (a) Pilot scale scrubbing and sieving, (b) Cross belt mag-netic separation, (c) Wet high intensity mag-netic separation, (d) Rare-earth magnetic sepa-ration, (e) Magnetic drums/rolls for fines sepa-ration, (f) Non-magnetic drums for fines sepa-ration, (g) Laboratory and pilot heavy media cone/cyclone, and (h) pilot and industrial scale testing on TRIFLO heavy media separation.

After taking into consideration the mineralogical and physical characteristics of the different min-erals occurring in the R.O.M. fines, two main

processing methods, gravimetric and magnetic separation, were decided to be examined in the laboratory, parallel to the optical separation tests. For the gravimetric separation test work, a dense media WEDAG Cyclone, and a dense media WEMCO Cone were used. For the mag-netic separation test work, a cross belt magnet (dry), an ERIEZ WHIMS electromagnet (wet), and an ERIEZ Rare Earth Roll magnet (dry) were employed.2,3,7

Considerable mineralogical research4,5 was exe-cuted also, during this stage of laboratory re-search, in order to evaluate the results obtained from the processing test work, and to acquire supplementary information on the physical characteristics of the 0-12mm material. From the investigation applied, valuable information was produced, concerning the quality of non-magnetic products, middlings, sinks and floats. Moreover, the material’s behaviour during siev-ing and processing was adequately explained with the assistance of mineralogy.

4. 4. DEVELOPMENT OF THE ORE MODEL DEVELOPMENT OF THE ORE MODEL

Model-based, steady-state optimisation was used as the most powerful approach to maxi-mise the efficiency at the design stage. An ore model was developed to represent processed material. Mathematical models were selected, adapted or developed, for several unit opera-tions, which were considered in the compilation of the final flow-sheet. Model parameters were determined from extensive laboratory, pilot plant and industrial testing. Lastly, the process flow-sheet was defined, simulated and opti-mised. The USIM PAC8 software, developed by CI.S.A., was used for the simulation. It was, therefore, very important to develop a reliable Ore Model that could be incorporated into the software and, thus, help to predict the efficiency of the different processes/methods during simu-lation. To achieve this, a number of assump-tions were adopted that allowed the conversion of assays into mineral phases comprising vari-ous combinations of the minerals identified. These assumptions were based on detailed ex-



perimental studies, and mainly the accurate mineralogical examinations and observations. They are summarised below:7 • Total CaO contained in the material, is as-

sumed to be associated with CO2, forming CaCO3. It is considered that 80% of total CaCO3 estimated, occurs in the form of dolo-mite.

• The remaining amount of CO2 occurs in the form of magnesite (MgCO3). ‘Pure’ magnesite grains are considered to contain 95% MgCO3 and 2.5% SiO2. A typical grade of composite magnesite grains is 75% MgCO3, and 15% SiO2. A proportion of 20% of total MgCO3 is assumed to occur in the form of composite magnesite grains.

• Typical grade of ‘silica’ grains is 20% MgCO3 and 70% SiO2. A proportion of 10% of total SiO2 is in the form of ‘silica’ grains, and

• Typical grade of serpentine grains is 7% MgCO3, and 50% SiO2.

5. 5. REMARKS AND CONCLUSIONSREMARKS AND CONCLUSIONS

The significant role of mineralogy during min-eral processing was stressed in the aforemen-tioned paragraphs. More specifically, mineralogy provided a fundamental and significant key in-put for the MAGFINES project in order: • To acquire a clear and accurate description of

the materials under investigation as per their composition, their liberation characteristics, non-desirable impurities in the valuable min-erals, as well as peculiarities of grains.

• To predict the materials’ behaviour against the available processing methods/techniques, based on the above information, thus pre-selecting the appropriate ones and avoiding unnecessary efforts.

• To evaluate the beneficiation results, and ap-ply alternatives, as well as to develop innova-tive routes and to conclude with the compila-tion of a generic flow diagram.

• To ‘construct’ a tailored ore model appropri-ate for simulation purposes.

Thus, with the help of mineralogy, it was appar-ent from the project start that no high magne-site grades could be expected from the treat-ment of this R.O.M., since there are many com-posite magnesite grains with such impurities

(i.e., silica) that may equally accompany con-centrates or tailings. Taking into consideration, material composition, and distribution of miner-als over the different size fractions, it became obvious that no method could alone be effective for processing. There should be an appropriate combination of methods (i.e., magnetic separa-tion, gravimetric separation). Moreover, the overall research was applied and focused to the development of routes that could be incorpo-rated in the existing GM company’s mill. Con-ventional equipment, such as drums may be used in an innovative way for the simultaneous removal of fines and gangue, since traditional screening of the specific 0-12 mm material is problematic.

In conclusion, the effective collaboration of the mineralogist and process engineer may not only facilitate scientific research for a specific mate-rial’s beneficiation, but it may also produce in-novative ideas, and result in a successful com-pletion of a project.

REFERENCESREFERENCES

1. Arvidson, B. & Reynolds, M, 1995. New Photometric Ore Sorter for Conventional and Difficult Applications. Proc-essing for Profit. 1 International Minerals Processing Conference, Amsterdam, 26-27.

2. Brite-Euram II, 1993a. New Process Routes for the Re-covery of Magnesite Run-Of-Mine Fines. 1st Progress Report, November 1st/1992 - April 30th/1993. June 1993, 1-8.

3. Brite-EuRam II, 1993b. New Process Routes for the Re-covery of Magnesite Run-Of-Mine Fines. 1st Annual Pro-gress Report, November 1993, Chapter 2, 27-39.

4. Brite-EuRam II, 1994a. New Process Routes for the Re-covery of Magnesite Run-Of-Mine Fines. 3rd Progress Report, Chapter 3, 6-8.

5. Brite-EuRam II, 1994b. New Process Routes for the Re-covery of Magnesite Run-Of-Mine Fines. 2nd Annual Pro-gress Report, December 1994, chapter 4, 17-20.

6. Brite-EuRam II, 1995. New Process Routes for the Recov-ery of Magnesite Run-Of-Mine Fines. Final Technical Re-port, December 1995, 26-34.

7. Brite-EuRam II, 1995. New Process Routes for the Recov-ery of Magnesite Run-Of-Mine Fines. Final Technical Re-port, December 1995, 83-91.

8. Broussaud, A., Guillaneau, J.-C., Guyot, O., Pastol, J.-F. & Villeneuve, J., 1991. Methods and Algorithms to Im-prove the Usefulness and Realism of Mineral Processing Plant Simulators. Proceedings of the XVII International Mineral Processing Congress. Dresden, Germany. Sep-tember 23-28, 229-246.


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.

« L I T H O S » « L I T H O S » T H E A C C R E D I T E D O R N A M E N T A L S T O N E T H E A C C R E D I T E D O R N A M E N T A L S T O N E

QUALITY CONTROL LABORATORY OF THE I.G.M.E.QUALITY CONTROL LABORATORY OF THE I.G.M.E. ([email protected])

The Laboratory’s “Scope of Accreditation” includes

solely EN Standards “Test Methods”, following the

current practice in EU Member States.

Some EN Standards determine “Requirements” on

the final products of various ornamental stones

for the purpose of assigning the relevant CE

marking, in relation to their potential application.

For certain product types

and applications, the CE

marking is gradually becom-

ing obligatory in Hellas. Thus, without the CE

marking, these products will not be able to face

competition in the European and International

markets. For this purpose, LITHOS is in the proc-

ess 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.

Although the Laboratory’s

activities are mainly re-

lated with natural orna-

mental stones, where the

existing equipment per-

mits, other types of rele-

vant materials (i.e.,

aggregate concrete ma-

sonry units, concrete pav-

ing flags, agglomerated

stones, etc.) can also be

tested.


Dr. Kostas Laskaridis Geologist ([email protected])

I.G.M.E., Division of Economic Geology, LITHOS laboratory


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.

In Ancient Hellas the use of marble had been very wide. Marble and stone were the materials that deeply touched the human sensitivity and driven humans to the world of aes-thetics and symmetry.

Marble has been used in Hellas for the construction of sacred buildings, since early recorded times. The an-cient Hellenes were the first, among many ancient civilisations, to notice the unique properties of this re-markable durable stone, which re-mains so beautiful and can be easily shaped according to their needs. Marble quarrying in Hellas started several centuries ago. The earlier statues go back to the Middle Neo-

lithic era (about 5,000 B.C.) with marble female idols, whilst later the series of the famous Cycladic idols followed. The first monuments of Hellenic sculpture (marble was used in combination with porous-material) appeared as early as 630 B.C. Representative examples of such monuments were the temple of Zeus at Olympia, as well as the tem-ple of Apollo at Delphi, with marble from the island of Paros in the fa-çade and porous-sandstone for the remaining part of the construction. The peak of the Hellenic Classical Period is represented by such out-standing structures as the Athens Acropolis with the Parthenon and Erecthion, the Aphrodite of Milos,

1. 1. INTRODUCTIONINTRODUCTION

AbstractAbstract

This article gives an overview of the Hellenic marble sector, and provides information on its 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-its, mainly white types, in combination with a very long tradition in the art of marble, the roots 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-tive natural stones, both in size of production and exports.

H E L L E N I C M A R B L E T H R O U G H T H E A G E S : H E L L E N I C M A R B L E T H R O U G H T H E A G E S :

A N O V E R V I E W O F T H E M A R B L E P R O D U C I N G A N O V E R V I E W O F T H E M A R B L E P R O D U C I N G

A R E A S A N D T H E S T O N E S E C T O R O F T O D A Y A R E A S A N D T H E S T O N E S E C T O R O F T O D A Y

Hellenic Stone Sector

Marble Sector

Marble Producing Areas

Marble Imports-Exports


the Hermes of Praxitelis, etc.

The history of the Modern Hellenic marble in-dustry started in the 1960's, when building ac-tivities and standards of living rose remarkably. The number of marble quarries has been con-tinuously increasing since the 1960's.

2. 2. TERMINOLOGY TERMINOLOGY -- GEOLOGY GEOLOGY

The commercial use of the term “marble” – “μάρμαρο” (marmaro) in the Hellene language - does not only include the metamorphic lime-stone formations, but also any ornamental stone that can be cut to standard dimensions, can be cleaned to a mirror finish – polished, and finally used in the decorative marble art. In general, the name “marble” is given to a variety of rock types, such as metamorphic rocks, e.g., crystalline limestone, and/or sedimentary rocks, for instance, calcareous alabasters, etc. Cur-rently, although there is still a habit of calling ornamental stones by their traditional names (some of them given in antiquity), norms are being developed (e.g., by CEN TC 246) to char-acterise a rock by its traditional name, by its petrographical name and its place of origin (“Denomination Criteria”– EN 12440).

The geological history of Hellas has been influ-enced by conditions of intense orogenesis, mag-matism and metamorphism that led to the de-velopment of extensive deposits of ornamental stones. Today, in Hellas the following ornamen-tal stones are widely used:

• Metamorphic rocks: Calcitic marble, dolomitic marble, cipolline marble, gneiss and ophical-cite.

• Sedimentary rocks: Limestone, travertine, breccia, onyx and alabaster.

• Magmatic rocks: Granite and granodiorite.

3. 3. HELLENIC MARBLE PRODUCING HELLENIC MARBLE PRODUCING AREAS (DEPOSITS) IN ANCIENT AREAS (DEPOSITS) IN ANCIENT AND MODERN TIMESAND MODERN TIMES

Hellas is extremely privileged with regard to marble deposits, and is one of the major pro-

ducing countries in the World. It provides the global market with rare varieties of marble that can scarcely be found elsewhere, and which have greatly contributed to the history of civili-sation.

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 century, intensive quarrying is reported in the following exploitation centres: Penteli and Aghia Marina of Attica area, the islands of Naxos, Paros (the famous marble of Paros, better known as ‘lychnitis’ has been quarried since an-tiquity) and Thassos (white marble quarried at the Capes of Alyki, Fanari and Vathi), and Phi-lippi, near to Kavala, for white marble. Tinos Island, Styra and Karystos on Evia Island (famous in ancient times for the marble quar-ried by the name ‘Karystia lithos’ or ‘Cipollino of Karystos’), Hassabali near to Larissa and Kro-kees in Peloponissos (famous for the greenish ‘krokeatis lithos’) for green marble. Eretria on the island of Evia for red marble and finally Sky-ros Island (‘marble of Skyros’, this name was given to the conglomerate that was quarried in ancient times) for multi-coloured marble.

In the early 20th century, extensive exploitation has started and marble has been exported in Western Europe. Thus, the Hellenic marble be-came well known abroad. The intensive exploi-tation of Hellenic marble starts in the 1960’s, as a result of the sudden development of construc-tion in urban centres, and the higher standard of living. Marble became a widely consumed in-dustrial product, with increasing demand, par-ticularly in large constructions and specific uses. To meet these demands, further increase of marble production was necessary, and it was achieved through the exploitation of new re-serves all over the country. In parallel, new modern cutting and processing units were de-veloped.

A brief description, and the current status of the

major Hellenic marble producing areas, is given

below (Figs. 1 & 2).

HELLENIC MARBLE THROUGH THE AGESHELLENIC MARBLE THROUGH THE AGESHELLENIC MARBLE THROUGH THE AGES


3.1. Drama, Kavala and Thassos Regions (Eastern Macedonia)

In the marble-bearing beds of Kavala and Drama units (Rhodope Massif), the metamor-phic carbonate rocks (calcitic and dolomitic) are widely distributed.

The most important marble producing locations in this area are: Thassos Island (white of Saliara Thassos, white of Limenas Thassos ‘Prinos’, Crystallina of Thassos), Volakas (White of Volakas, the most exported Hellenic marble to China), Stenopos (Semi-white of Kavala), Nestos, Limnia, Nikissiani, Piges, Elaphohorio, Dysvato, Vathilakos, and Palia Kavala.

3.2. Kozani and Veria Regions (Western Macedonia)

From this area white and white-whitish and col-oured marble of superior quality is quarried

(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’ l i m e s t o n e , c a l l e d ‘gianniotico’, is quarried. It used to be the most utilised ornamental stone in the Hellenic construc-tion industry, due to its nice colour and low price.

3.4. Larissa & Volos Regions (Thessaly)

The area of Larissa and Volos offers a great vari-ety of white, whitish, pink, and coloured mar-ble. The marble of Tis-saion Mountain (pink of Lafkos), at the southern end of Magnesia penin-

sula, is of great economic value. Intensive ex-ploitation took place during ancient times.

3.5. Penteli (Attiki Region)

This area produced the world famous Pentelikon white marble, by the names ‘Bianco di Pendeli’ or ‘Marmo Greco Fino’. Penteli marble quarrying started in ancient times, and continued system-atically up to 1976, when the quarrying activity in the south-western slopes of Penteli has ceased, due to measures taken for environ-mental protection. The white marble quarrying has been restricted ever since in the northern part of the Penteli Mountain. In the areas of Dionyssos and Aghia Marina about 10,000 to 15,000 m3/year are produced. Today, system-atic exploitation (mainly underground) of the Dionyssos marble continues in the area of Pen-teli.

Figure 1. Main Hellenic marble producing areas.



3.6. Levadia and Domvrena (Sterea Hel-las)

The areas of Levadia and Domvrena, offer a wide variety of pink-white, whitish, black and coloured marble. The most important marble types in the area are: Whitish of Helikona, Pink of Levadia, and the Black of Levadia.

3.7. Other Regions

Apart from the above mentioned important pro-duction and processing centres, it is worth not-ing the marble exploitation in many other areas, such as the Aegean islands: Naxos (White-Semi white Crystallina of Naxos), Tinos (Green of Ti-nos), Paros (Semi-white), Evia (Green of Styra, Black of Aliveri, multi coloured marble of Sky-ros, etc.), Crete and Argolis regions (Peloponissos), where mainly beige marble types (Karnazeika, Didyma, Ligourio, etc.) are quarried.

Figure 2. Number of quarries per region (Data 2004).

4.4. MAIN APPLICATIONS OF STONESMAIN APPLICATIONS OF STONES

Today, the most common applications of dimen-sional stones are facings and floorings, both in-ternal and external, gravestones and sacred art, structural applications, special works, such as refurbishing, restoration and roofing, staircases, interior (skirting boards, door stones, window

sills) and exterior decorations (window ledges, door stones, copings, profiles), and furnishings.

5.5. STONE SECTOR IN HELLAS STONE SECTOR IN HELLAS -- CURRENT STATUS CURRENT STATUS

The modern and dynamic Hellenic marble indus-try is rated among the top world producers of decorative natural stones, with respect to both size of production and exports. Now-a-days, quarrying companies are scattered all over Hel-las, since there are marble deposits almost in the whole territory (Fig. 1).

The number of companies engaged in the mar-ble sector is estimated to be about 4,000 (6.7% of the Dimension Stones Sector in Europe), and includes small, medium-sized, and also several large units that they have made important in-vestments, and rank among the best industrial units in Europe. The Hellenic marble sector em-ploys more than 60,000 people (12% of the European employment sector); a large number have a high level of specialty in the fields of quarrying, processing and installation of marble. The Hellenic marble companies are mainly en-gaged in one of the following fields: Quarrying, Cutting and/or processing, Manufacture of art works, Ecclesiastical elements and Memorials, Trade of marble blocks, and a variety of prod-ucts for the home and foreign markets, Installa-tion and applications. However, there are sev-eral companies that have achieved vertical or-ganisation.

The marble quarry production has impressively increased during the last few years. The total quarried production has risen sharply. In year 1966, the quarried production of marble blocks was 141,000 tonnes. In 2002 and 2003, the an-nual production was ca. 2,100,000 tonnes, or 3% of the world ornamental stone production. In 2004, the annual production decreased to 1,400,000 tonnes or 1.8% of the world orna-mental stone production (Fig. 3).

According to 1996 data, collected from Statisti-cal Institutes of E.U. States, Hellas occupies the fifth position in the world quarry production and

79

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6

26

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173 6

Eastern Macedonia Central MacedoniaWestern Macedonia EpirusThessalia Sterea HellasPeloponnese Kyklades islandsCrete Other regions



export of ornamental stones, after Italy, China, Spain and India. However, due to strong com-petition, Hellas is gradually loosing this position. In 2003, Hellas occupied the ninth, and in 2004 the eleventh position among the top ornamental stone producing countries in the World, after China, India, Italy, Spain, Iran, Turkey, Brazil, Egypt, Portugal and U.S.A.

Exporting activity has also decreased, with total unprocessed and processed ornamental stones exported amounting to around 377,840 tonnes in 2002, 414,000 tonnes in 2003, 387,000 ton-nes in 2004, and 361,000 tonnes in 2005, from 206,770 tonnes in 1991 (Fig. 4).

The problems with the environmental legisla-tion, and the growing bureaucracy for new quarrying licenses, have led the marble sector companies to increase imports of raw material.

Imports value (both of processed and unproc-essed marble, granite, etc.) is 65 million € for 2005, marking an increase of about 23.2% compared to the 2002 value (41.4 million €), and an increase of around 208% compared to the 2001 value (31.2 million €). Importing ac-tivity has increased from 74,757 tonnes in 1998 to 404,283 tonnes in 2005 (Fig. 5).

The first 10 import-markets in 2005 occupy a share of 92.7% in quantity of the total imports, with Turkey having by far the largest share of Hellenic imports.

The main import markets for ornamental stones in 2004, according to quantity, were Turkey,

FYROM, Albania, Bulgaria, Morocco, Egypt, China, Syrian, Italy, and In-dia.

The main import markets for orna-mental stones in 2005, according quantity, were Turkey, Albania, FY-ROM, Bulgaria, Egypt, Morocco, Syrian, China, India, and Italy.

The marble sector, as it is export oriented, constitutes one of the few sectors in the Hellenic economy, which is in a position to compete in the international market. Total exports value is of €105,197,000

(both of processed (66.9%), and of unproc-essed marble (blocks and slabs 33.1%) for 2005, marking a decrease of around 16%, com-pared to the 2001 value (€125,115,000), and a

0

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Figure 4. Export of unprocessed and processed Hellenic marble (in tonnes).

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Figure 5. Evolution of import of ornamental stones in Hellas.

Figure 3. The annual marble quarry production in Hellas from 1966 to 2004 (Production in m3).



decrease of around 14%, compared to the 2004 value. But, when compared to the 1991 value (€57,872,000) there is an increase of 181.7%.

The first 10 export-markets occupy a share of 71.6% in value of total exports, with U.S.A. having by far the largest share of Hellenic ex-ports.

The main markets for Hellenic marble in 2002, according to total value, were U.S.A., China, Spain, Cyprus, Hong-Kong, Germany, Japan Saudi Arabia, Italy, and Brazil. The first 10 ex-port markets in 2002 occupy a share of 55.88% in quantity of total exports, with China having by far the largest share of Hellenic exports. The main markets for Hellenic marbles in 2002, ac-cording to quantity, were China, Spain, Saudi Arabia, Cyprus, U.S.A., Hong-Kong, Italy, Ger-many, Japan, and Brazil.

The first 10 export markets in 2005 (U.S.A., Saudi Arabian, China, Cyprus, Japan, Brazil, Spain, Italy, Germany, and Hong Kong.) occupy a share of 68% in value of total exports (107.5 million €). The first 10 export markets in 2005 occupy a share of 53.8% in quantity of total ex-ports, with China having by far the largest share of Hellenic exports (35%). The main mar-kets for Hellenic marble in 2005, according to quantity, were China, Hong Kong, U.S.A., Cy-prus, Italy, Spain, Brazil, United Arab Emirates, Germany, and Japan.

5.5. CONCLUSIONSCONCLUSIONS

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 com-petition.

Hellas offers a wide variety of marble of differ-ent aesthetic and technical characteristics ap-propriate for all uses. Modernised quarrying takes place all over Hellas. Commercial compa-nies 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

published in 2006 the fourth edition of the Hel-lenic Marble Directory.

The I.G.M.E. is supporting the Hellenic marble sector by conducting research for new marble deposits, using new methods and by introducing quality control in the Hellenic marble products (LITHOS laboratory). The I.G.M.E. can provide information, advice and support to anyone in-terested in the Hellenic marble sector.

BIBLIOGRAPHYBIBLIOGRAPHY

Founti, M., 2004. Stone for construction and architec-ture - From extraction to the final Product. OSNET Editions, Volume 10, Technology Transfer Sector, June 2004, 164 pp.

Giannaros, G., 1999. Foundation of Economic and Industrial Research (IOBE), Greek marble sectors study, 18 pp. In: http://www.osme.8m.com/kladikimeleti.doc

http://www.acci.gr : Athens Chamber of Commerce & Industry.

http://www.statistics.gr : National Statistics Service of Hellas (NSSG).

Laskaridis, K., 2004. Greek Marble through the ages: An overview of geology and the today stone sec-tor. Final OSNET Workshop Ioannina, Hellas, 30 Sep. 2004, 17 pp.

Marmaro, Special Edition, Marmin 2006. Business Data Ltd., May 2006, 274 pp.

Ornamental Stone from Greece, Editions Hellenic Marble, Issue 23, May 2004, 146 pp.



AbstractAbstract

Concrete is the product of mixing aggregates with Portland cement and water. The mixture 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 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 normally used as aggregates are carbonate rocks, which are the most widespread nationally. 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, dolomite and others, which under special conditions can react with the cement paste, causing 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.

T H E C O N T R I B U T I O N O F P E T R O G R A P H Y T H E C O N T R I B U T I O N O F P E T R O G R A P H Y

T O T H E E V A L U A T I O N O F C A R B O N A T E T O T H E E V A L U A T I O N O F C A R B O N A T E

A G G R E G A T E S F O R C O N C R E T E P R O D U C T I O N A G G R E G A T E S F O R C O N C R E T E P R O D U C T I O N

Concrete Aggregates

Deleterious Minerals

The Alkali-Silica Reaction

Petrographical Evaluation

Marina Dimitroula Mineralogist ([email protected])

I.G.M.E., Division of Mineralogy & Petrography


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.

Concrete is the product of mixing aggregates (coarse and fine) with Portland cement and water. The ag-gregates are, by volume, the major constituents of concrete (~80%) and the rest is cement (~20%). The water/cement ratio is about 0.5. Water and cement form the paste, while the aggregates the inert filler.

The dried mixture is compact and dense, known as “concrete”, which is widely used as a building con-struction material. The aggregates employed in concrete production, are various types of rocks, which comply with National and/or Inter-national specifications. In Hellas, the rocks usually used as aggregates for



PETROGRAPHICAL EVALUATION OF CONCRETE AGGREGATESPETROGRAPHICAL EVALUATION OF CONCRETE AGGREGATESPETROGRAPHICAL EVALUATION OF CONCRETE AGGREGATES

concrete production are the carbonate rocks, which are the most abundant in the country. Carbonate rocks are considered among the most suitable for concrete production, provided they do not contain deleterious minerals, which according to their quantity or distribution could have adverse effects on the production of a “good quality” concrete.

2. 2. DELETERIOUS MINERALS IN DELETERIOUS MINERALS IN AGGREGATESAGGREGATES

According to (a) the specification EN 126203, and (b) the 1997 Hellenic National specification for concrete production,6,7 the deleterious min-erals contained in the aggregates are some dis-ordered forms of silica (opal, chalcedony, stressed quartz, volcanic glass), clay minerals, some magnesium minerals, coal, organic mat-ter, pyrite and others (Fig. 1).

Sometimes, only a small quantity of these min-erals in the aggregate can cause problems in 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 ag-gregates should not exceed 1% by weight (for fly ash it is 2%). If pyrrhotite is present in the ag-gregates, then the total sul-phur should not exceed 0.1%. Taking into account, the above mentioned min-erals and quantities, it is obvious, that aggregates should be carefully exam-ined, before their use in concrete production.

3.3. PETROGRAPHY OF PETROGRAPHY OF CARBONATE ROCKSCARBONATE ROCKS

Limestone and dolomite, the principal calcare-ous rocks, are composed essentially of carbon-

ate minerals, calcite (CaCO3) and dolomite (Ca,Mg)CO3. A rock to be classed as calcareous should contain at least 50% lime-carbonate minerals. Rocks con-sisting largely of calcite are termed as lime-stone; those containing additionally

magnesium carbon-ate are called dolomite

or dolostone, and mix-tures of calcite and dolomite

are referred to as dolomitic lime-stone or calcitic-dolomite, depending on the proportion of the main min-eral. The term “magnesian limestone”

is applied by some to limestone con-taining dolomite in amounts of less than

10%, while by others to limestone in which visible dolomite is lacking, but carries

considerable magnesium, as indicated by chemical analyses. Limestone is a relatively pure carbonate rock. Accessory minerals are

a

b c

d

Figure 1. Microphotographs of disordered forms of silica in limestone aggre-gates (the insoluble material):

(a) The insoluble material of some limestone aggregates;

(b) Radiolaria in some limestone aggregates (+N, x500);

(c) Chalcedony with some calcite in the limestone aggre-gates (+N, x500);

(d) Clayey material in limestone aggregates (+N, x500.


usually about 5% by volume. If the accessory constituents are abundant, the rock name is modified accordingly to suit the particular com-position. Glauconitic, cherty, sandy and argilla-ceous limestone types are particularly common. Similar terms are applicable to dolomitic lime-stone, calcite-dolomite and dolomite. By in-creasing the content of non-carbonate materi-als, calcareous rocks grade into other rock types; thus, sandy limestone grades into cal-careous sandstone, and argillaceous limestone into marl and calcareous shale.

In calcareous sediments many minerals, other than carbonates, occur. Some are simply detri-tal or pyroclastic grains, washed or blown into the depositional basin, and mechanically mixed with carbonate material. There is no limit to the variety of rock particles and minerals that may be included in this manner, but as may be ex-pected, quartz and clay are the commonest. Other non-carbonate constituents are organic remains, such as the opal of diatom and radio-larian shells and sponge spicules; the cello-phane of bones, teeth, and some brachiopod shells; and the calcareous pigment, which dark-ens many types of limestone. Authigenic miner-als may also be present. These may be formed, either almost contemporaneously with the cal-careous deposits, or later, during and after lithification. Among the commonest of these minerals are chalcedony, quartz, glauconite, pyrite, gypsum anhydrite and alkali feldspars.9

4. 4. LIMESTONE AND THE ALKALILIMESTONE AND THE ALKALI--SILICA SILICA REACTION REACTION

Limestone aggregates for concrete production, should be hard, durable, clean, and mainly al-most free of clay and disordered forms of silica, which, under special conditions, could react with the alkalis in the cement pore fluids, causing Alkali-Silica Reaction (ASR) or Alkali-Carbonate Reaction (ACR), inducing expansion and crack-ing in concrete. ASR is a chemical reaction be-tween disordered forms of silica, which may oc-cur in aggregates, and hydroxyl ions, formed by the release of alkali compounds from the ce-

ment. The reaction forms a swelling gel, which may induce stress, resulting in expansion and cracking of the concrete, which over time can threaten the safety of the whole structure. A combination of the following factors may lead to ASR-induced cracking:

• presence of disordered silica forms;

• available alkalis (generally from cement), above a critical level, and

• moisture from an external source.

The reactivity of silica depends on the degree of order in the crystal structure. Opal, is highly disordered, and is the most reactive form of sili-ca. In contrast, well-ordered unstrained quartz is usually non reactive. Other undesirable forms of silica are tridymite, cristobalite, chalcedony (chert, flint, etc.), microcrystalline quartz, strained quartz and volcanic glass. There are guidelines for minimising ASR in new construc-tions by using aggregates, which contain less than 2% by volume, or more than 60% reactive silica.1,2

Another type of alkali-aggregate reactivity is the Alkali-Carbonate Reaction (ACR), occurring when certain carbonates react with alkalis to cause expansion and cracking.5 Potentially dele-terious carbonates are the dolomitic varieties, especially those with high clay content. There are a number of tests for assessing the reactiv-ity of aggregates, such as the ASTM C289 quick test, the ASTM C227 mortar bar expansion test, and the gel pat test. Petrographical examination of aggregates is also an important assessment procedure (ASTM C295). In addition, Lorenzi et al.8 state that “the petrographical analysis points out opposite behaviours of the lime-stones with regards the ASR. Some of these rocks with silicifications show high reactivity or no reactivity at all, while others, without visible silicifications, can be reactive. Thus, the pres-ence of visible secondary diagenetic silica within limestone is not a prerequisite to promote the Alkali-Silica Reaction, and the absence of visible silica does not necessarily mean that the lime-stone is not reactive.”



5. 5. PETROGRAPHICAL EVALUATION OF PETROGRAPHICAL EVALUATION OF LIMESTONE AGGREGATES LIMESTONE AGGREGATES

Taking into account: (1) the petrography of limestone (above) and its non-calcareous min-erals; (2) the minerals considered as deleteri-ous for causing Alkali-Silica Reaction, and (3) the results of Lorenzi et al.8 that “the petro-graphical analysis points out opposite behav-iours of the limestones, with regards the ASR”, it is concluded that limestone should always be examined, according to National and Interna-tional Specifications, although they are consid-ered among the most suitable rocks for produc-ing concrete aggregates.

It must also be emphasised, that petrographical analysis is a very important “tool” for the evaluation of concrete aggregates, because the use of different petrographical methods (Optical microscope, X-Ray Diffraction Analysis, Elec-tronic Microscope Analysis), offer rapid and very good results. Sometimes, use of the optical mi-croscope is inevitable, because some minerals like chalcedony, volcanic glass or stressed quartz, are impossible to identify by other methods. It should also be stressed that by studying the aggregates in thin section, the rock fabric is studied, especially the porosity of the rock, which plays a very important role for the quality of concrete. Only petrographical analysis gives full information about the quan-tity, type, size, shape and distribution of pores in an aggregate (EN 12620 F.1.3 & F.2.2).3 Petrographical analysis again, is probably one of the best methods to identify the Alkali-Silica Reaction in concrete. It is stressed that “the ex-amination should be carried out by a qualified geologist (petrographer), with experience in materials used in civil engineering”.6,7

5. 5. CONCLUSIONS CONCLUSIONS

Summarising the above concise account about the characterisation of aggregates in concrete production, the following conclusions are made:

• Limestone is considered to be the most suit-able rock for concrete aggregate production,

provided that it does not contain deleterious minerals.

• The deleterious minerals in limestone are mainly the disordered forms of SiO2 and clay minerals.

• Among the methods testing aggregate mate-rials for concrete production, petrographical analysis is considered a “must”.

• Petrographical analysis alone is, however, not sufficient to test the suitability of concrete aggregates. Similarly, chemical analyses and durability tests alone or in combination, are also not adequate for testing concrete aggre-gates.

• Limestone aggregates are suitable for con-crete production, provided they always com-ply with the recommended Aggregate Specifi-cations, and their testing includes a combina-tion of Durability Tests, Chemical and Petro-graphical Analyses.


1. Concrete Society, 1999. Alkali-silica reaction: minimising the risk of damage to concrete. Technical Report 30. C o n c r e t e S o c i e t y , L o n d o n , 7 2 p p . [www.concrete.org.uk].

2. Department of Transport, 1991. Specification of Highway Works. HMSO, London.

3. European Standard, 2002. EN 12620, Aggregates for concrete. European Committee for Standardisation, Brussels, 47 pp.

4. Central Laboratory of Public Projects, 1997. Hellenic specifications for Concrete Production. Central Labora-tory of Public Projects, Ministry of Environment, Physical Planning and Public Works, Athena, Hellas, 58 pp.

5. Gillot, J.A. & Swenson, E.G., 1969. Mechanism of the alkali-carbonate rock reaction. Quarterly Journal Engi-neering Geology, 2, 7-23.

6. Hellenic Organisation for Standardisation, 1985. Specifi-cations of crushed aggregates for common concrete. ELOT document 408, Athena, 20 pp.

7. Hellenic Organisation for Standardisation, 1996. Tests for general properties of aggregates. Part 3: Procedure and terminology for simplified petrographic description. ELOT document 932.03, Athena, Hellas, 20 pp.

8. Lorenzi, G., Guėdon-Dubied, S. & Antenucci, D., 2001. 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-terials. Athena, Hellas, 4-7 September 2001, 626 pp.

9. Williams, H., Turner, F.K. & Gilbert, C.M., 1954. Petrog-raphy. An introduction to the study of rocks in thin sec-tions. W.H. Freeman & Company, San Francisco, 406 pp.



AbstractAbstract

Some constructional and decorative materials used in buildings exhibit high levels of radioactiv-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 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.

R A D I O A C T I V I T Y C O N T R O L R A D I O A C T I V I T Y C O N T R O L O F B U I L D I N G A N D D E C O R A T I V E M A T E R I A L S O F B U I L D I N G A N D D E C O R A T I V E M A T E R I A L S

Decorative Materials

Construction Materials

Radioactivity

γ-radiation

Specific Radioactivity

Faedon Pergamalis, Dimitris E. Karageorgiou, Athanasios Koukoulis, Dimitris Persianis Geologists ([email protected] )

I.G.M.E., Division of Solid Fuel Resources


ΕΛΕΓΧΟΣ ΡΑΔΙΕΝΕΡΓΕΙΑΣ ΣΕ ΔΟΜΙΚΑ ΚΑΙ ΔΙΑΚΟΣΜΗΤΙΚΑ ΥΛΙΚΑ: Ορισμένα δομικά και διακο-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.

Public awareness has been raised in recent years, both in Hellas and worldwide, with respect to the qual-ity of life, making imperative, there-fore, the taking of certain precau-tions. One such action concerns ex-posure to increased radioactivity, which unintentionally is caused in the interior of buildings by a variety of construction materials. Events that had been over emphasised from time to time in the daily press may be recalled, as for example, the ex-istence of radioactive casings, ce-ment with increased radioactivity, coloured sanitary ware materials, as well as other decorative materials for which there is great suspicion in the minds of consumers.

It should be noted that in some countries, the import of construction and decorative materials requires

that they are accompanied by an official certificate of radioactivity measurement.

2. 2. RADIOACTIVITY IN RADIOACTIVITY IN GENERAL GENERAL

As natural radioactivity it is defined the γ-radiation of short wavelength, which is emitted by primary raw ma-terials, and to which is added the natural radioactivity from cosmic radiation. In this way a natural aver-age level of radioactivity is formed (known as background radiation), which is a characteristic feature of an area.

What is important is for this natural radioactivity level not to be dis-turbed by the accumulation of mate-rials with increased γ-radiation, be-cause the effects of exposure on the



RADIOACTIVITY CONTROL OF BUILDING AND DECORATIVE MATERIALSRADIOACTIVITY CONTROL OF BUILDING AND DECORATIVE MATERIALSRADIOACTIVITY 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 radio-activity background levels in the home and work environments. This can only be achieved by a strict control of the materials used in the con-struction 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 anomaly. In the interior of buildings, where there is an accumulation of such materials, and especially in confined spaces that are not well aerated, the levels of γ-radiation increase sig-nificantly, posing, therefore, a health hazard.

For the objective control of radioactivity the fac-tor of “mass influence” is used. This means that a material with a large mass and low natu-ral radioactivity is possible to exhibit higher ra-dioactivity levels, in comparison to another with a smaller mass, but increased natural radioac-tivity. For this reason the term “specific radioac-tivity” 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 be-tween materials is made possible.

3.3. METHOD OF TESTING RADIOACTIVITY METHOD OF TESTING RADIOACTIVITY

The measurement of radioactivity must be car-ried out in a lead cage, so that the effect of cos-

mic radiation is practically minimised. One such cage consists of lead bricks, each having dimen-sions of 10x10x10 cm, a total volume 0.5 m3 and a weight of 350-500 kg (Fig. 1); other types of cages are shown in Figures 2 and 3.

Measurement of radioactivity in the cage can be achieved by the use of either a crystal of NaI, which is activated by Thallium, or by the use of a Germanium crystal of great purity, and a

Figure 1. Cage of lead bricks.

Figure 4. Instruments for measuring α-radiation.

Figure 2. Figure 3.

Other types of cages for measurement of γ-radiation.


maximum capability of distinguishing the en-ergy spectrum of γ-radiation, which is being cooled with N2, in accordance with the arrange-ment being used. The radioactivity measure-ment system is accompanied by:

• a pre-amplifier of the outgoing signal;

• a processing unit of the signal, of substantial capacity and speed, with built-in software, and the necessary peripherals;

• an amplifier;

• a high resolution screen, and

• a plotter.

A necessary prerequisite is that samples of ma-terial being tested should have prede-fined dimensions, so as to minimise even the slightest difference in the measurements that can be possibly introduced by the geometry of the material (Fig. 5).

The range of influ-ence of the angle during the measure-ment of radioactivity should preferably be 2π, so that over or under estimations are avoided (Fig. 6).

Mass is measured in grams, while radioactivity may be measured in the units of the instrument being used. Usually ticks per second (chocks/seconds), or units of radiation being absorbed (Becquerel or Micro Curie).

Apart from detecting unstable nuclei that are responsible for the radioactivity, it is possible to

monitor the geometrical characteristics of sam-ples, using a disc rock cutter, combined with the use of an α-radiation counter, enabling, thus, the estimation of “radioactivity balance”.

It should be, however, noted that comparison of materials must be done on the same measurement system, given that there is a wide selection in size and quality of crystals, which obviously have dif-ferent behaviour (Fig. 7).

There are obviously sys-tems that have the facility to both make a distinction between the radiating elements and to produce measurements in international units (Becquerel).

The I.G.M.E. is equipped with radioactivity measurement instruments, which can estimate the “specific radioactivity” of raw materials by examination of their quality and quantity char-acteristics, such as the chemical-mineral com-position, hardness, etc.

Hundreds of measurements of “specific γ-radioactivity” have been conducted on terres-trial rocks (n=2,570), as well as on samples from sea bottom sediments (n=419), and their corresponding range and average values are 45-10,850 x 10-4 (mean 422 x 10-4) and 20-516 x 10-4 (mean 78 x 10-4) ch/gr.sec.

Below four indicative measurements of specific radioactivity of decorative rocks are given:


Figure 5. Specific dimensions of test samples.

Figure 6. Measuring the correct 2π angle.

• Hellenic marble 21 x 10-4 ch/gr.sec

• Hellenic granite 104 x 10-4 ch/gr.sec

• Imported granodiorite 222 x 10-4 ch/gr.sec

• Imported aplite grano-

diorite

303 x 10-4 ch/gr.sec

Figure 7. Crystals for measuring γ-radiation.


Consequently, it would be advisable to monitor the level of radioactivity of imported materials, as well as to provide a certificate of radioactivity for materials being exported.

4. 4. AREAS OF APPLICATION AREAS OF APPLICATION -- CLIENTS CLIENTS

The certificate of suitability may be issued for use by:

• Exporters of building materials;

• Importers of decorative materials;

• Manufacturers and importers of sanitary ma-terials, and

• Manufacturers of cement products.

In parallel, the laboratory may be used to ex-amine radioactive contamination of the geologi-cal environment of residential areas by State Authorities (I.G.M.E., Ministry of Environment, Physical Planning and Public Works).

5. 5. ESTIMATE OF COST FACTORS ESTIMATE OF COST FACTORS

Market research has shown that the cost of a fully equipped radioactivity measurement labo-ratory, including software and peripherals, is about €60,000 excluding V.A.T. If an amortiza-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 amorti-zation.

6. 6. CONCLUSIONS CONCLUSIONS -- PROPOSALS 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 emit-ted 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-

requisite.

The cost of installation and operation of a labo-ratory of radioactivity measurement on con-struction and decorative materials is relatively low, and its amortization favourable, let alone the fact that it gives the possibility to the I.G.M.E to develop an income from this source.

On the other hand, the laboratory may be used for the measurement of radioactivity in residen-tial areas, as well as on raw materials for con-struction of highways, railways, etc. Therefore, the completion of the I.G.M.E. «Radioactivity Control and Attestation of construction and decorative materials Laboratory» is considered essential to fill a regulatory gap in Hellas.

BIBLIOGRAPHYBIBLIOGRAPHY

Dumoulin, C., 1980. Methodes de Prospection de l’ Uranium. COGEMA / C.I.P.R.A., France, 141 pp.

Pergamalis, F., 1998. Feasibility Study for the estab-lishment of a laboratory for the radioactivity con-trol of construction materials. I.G.M.E internal re-port, Athena, 5 pp.

Pergamalis, F., Karageorgiou, D.E. & Koukoulis, A., 2000. Radioactivity control of building materials. Proceedings of 3rd Congress of Mineral Research, Technical Chamber of Hellas, Athena, 383-386.



AbstractAbstract

The Greek geological domain is composed of pre-alpine crystalline rocks, alpine sediments, volcanosedimentary formations, and oceanic crustal and post alpine sedimentary-volcanic rocks. The Hellenides are subdivided into a number of geotectonic units, grouped into “Internal” and “External” ones. The complex geological structure of Greece favoured the formation of vari-ous types of mineral resources. The Internal Hellenides, host a variety of industrial minerals, formed either by magmatic or metamorphic processes (Endogenous Deposits). Several impor-tant Industrial Mineral prospects and deposits have been located in the Internal Hellenides in-cluding: olivine, magnesite, talc, vermiculite, feldspar, quartz, graphite, garnet, wollastonite, pumice, perlite, bentonite, kaolin, zeolites, pozzolana, etc. The External Hellenides are charac-terised by the presence of Industrial Minerals of sedimentary origin (Exogenous Deposits), in-cluding outcrops/deposits of bauxite, gypsum-anhydrite, white carbonate, attapulgite, phos-phate, 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 oc-currences/ deposits, thus, a continuous development of the industrial mineral sector is ex-pected.

Industrial Minerals

Endogenous Deposits

Exogenous Deposits

Hellenides

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


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.

A N O V E R V I E W A N O V E R V I E W

O F T H E I N D U S T R I A L M I N E R A L O F T H E I N D U S T R I A L M I N E R A L

R E S O U R C E S O F G R E E C E R E S O U R C E S O F G R E E C E


OVERVIEW OF THE GREEK INDUSTRIAL MINERAL RESOURCES OVERVIEW OF THE GREEK INDUSTRIAL MINERAL RESOURCES OVERVIEW OF THE GREEK INDUSTRIAL MINERAL RESOURCES

1. 1. INTRODUCTION INTRODUCTION

An Industrial Mineral (IM), as defined in the Glossary of Geologic Terms, is “any rock, mineral, or other naturally occurring sub-stance of economic value, exclusive of metal-lic ores, mineral fuels, and gemstones; one of the nonmetallics.”2 They may be classified into various groups using different criteria, such as fields of application (construction, chemical industry, glass and ceramics, fillers-extenders, etc.), geological criteria, or taking into consideration commercial/trading crite-ria.13,43

Industrial minerals occur in igneous, meta-morphic and sedimentary rocks, and may have been formed either by syngenetic or epigenetic processes in relation to their host rocks. In this article the Industrial Mineral resources (construction mineral resources are excluded) are discussed, according to their geological setting and processes that fa-voured their formation.

2. 2. GEOLOGICAL SETTING OF GREECE GEOLOGICAL SETTING OF GREECE

The Greek geological domain is a part of the Alpine Dinaric Arc and is referred to as “Hellenides”. It is composed of pre-alpine crystalline rocks, alpine sediments, volca-nosedimentary rocks, and oceanic crustal and post alpine sedimentary-volcanic rocks. The Hellenides are subdivided into a number of geotectonic units, grouped into “Internal” and “External” (Fig. 1). The Internal Hellenides have undergone deformation during two oro-genic cycles; the first in Late Jurassic-Early Cretaceous times, and the second during the Tertiary. The External Hellenides have been affected only by the last orogenic cycle.

The Internal Hellenides are comprised of the following geotectonic zones: (a) Rhodope, (b) Serbo-Macedonian, (c) Circum-Rhodope, (d) Axios-Vardar, and (e) Pelagonian. These zones consist mainly of low to high-grade metamorphic rocks (schist, gneiss, amphibo-lite, migmatite, anatectic granite, carbonate rocks, phyllite, mafic and ultramafic rocks,

and clastic sediments).

The External Hellenides consist of the following geotectonic zones: (a) Pindos, (b) Gavrovo-Tripolis, and (c) Paxos. Depending on the zone, they are mainly made up of neritic to pelagic sediments (carbonates, shale, mudstone, radio-larite, flysch). In certain zones, bauxite hori-zons, evaporites, volcanic and slightly meta-morphosed rocks, may occur.

During Palaeogene, the intense alpine orogenic phase produced post alpine sedimentary basin formations. The subsequent sedimentation was accompanied by intense collision type magma-tism that produced volcanic, sub-volcanic and plutonic rocks. The oldest magmatic rocks occur in Thrace, where as the most recent ones are found in the still active Hellenic arc.

3. 3. INDUSTRIAL MINERALS OF GREECE INDUSTRIAL MINERALS OF GREECE

The complex geological structure of Greece favoured the formation of various types of mineral resources. The Internal Hellenides, due to their constitution and evolution, host a variety of mainly endogenous industrial min-erals; these are formed either by magmatic processes, including magma differentiation, contact metasomatism, and hydrothermal ac-tivity, or by metamorphic processes, including contact-regional metamorphism.13 The Exter-nal Hellenides are characterised mainly by the presence of industrial minerals, mostly of weathering or sedimentary origin (Exogenous deposits), according to the same classification model.

3.1. Endogenous Type IM Resources

3.1.1. Mineral Occurrences of Primary Magmatic Origin

Olivine: Widespread ophiolite outcrops occur in Greece (Pindos, Vourinos, Chalkidiki, Thrace, Orthrys, etc.). Therefore, theoretically, there is a very high potential for the location of large dunite (olivine) deposits. On the other hand, the requirements of industry for unaltered olivine, in relation to the history of the ophiolite com-plexes, narrows the chances of finding fresh de-



posits. Occurrences of fresh olivine, suitable for high quality olivine products, have been located at Gerakini and Vavdos areas of Chalkidiki, as well as in the ophiolitic complexes of Vourinos and Pindos.1,8

Pegmatites, the last stage product of magma crystallisation (in certain cases may be products of anatectic processes), are the main source of K- or Na-feldspars, mica and quartz by-products (simple pegmatites). Apart from these, high rare mineral concentrations, such as beryl, to-paz, etc., may be hosted in “complex pegma-tites”. Widespread outcrops of simple type peg-matites have been located in metamorphic rocks in the Rhodope and Vertiskos zones (Protoklissi-Koryvos, Leptokarya, Paranesti, As-siros).9,31

Natural Pozzolanas, are materials of silica-alumina composition, which in the presence of water react with Ca(OH)2 to produce com-pounds with hydraulic properties. Volcanic rocks with pozzolanic properties are widespread in Greece. Large deposits of pozzolanic rocks occur on the islands of Milos and Santorini, as well as in the area of Aridea. Less important outcrops are located on the islands of Kimolos, Nisyros and Kos, as well as in some areas in Thrace.23

Pozzolanic properties are also displayed by zeo-litic tuffs (Polyegos, Dadia, etc.).29

Pumice, is light in colour, highly vesicular and lightweight rock, formed during the eruption of silicic magmas with a high volatile content. Ex-tensive exploitable pumice deposits exist on Santorini and Yali islands.

3.1.2. Mineral Occurrences Related to Alteration of Volcanic Rocks

Perlite, possibly formed by alteration of vol-canic glasses under the influence of hot va-pours, is light coloured, water bearing glassy volcanic rock, usually of rhyolitic composition. It expands to about 10-15 times its original vol-ume, after rapid heating at a certain tempera-ture. Large perlite deposits have been located on the islands of Milos and Yali. Less important outcrops occur on Kos, Kimolos and Lesvos is-

lands, and in the area of Alexandroupolis (Thrace) on the Greek mainland.18,20,21,22,55

Zeolites are usually products of alteration of the glass of volcaniclastic rocks, under diage-netic or low temperature hydrothermal condi-tions. Large zeolite deposits of possible eco-nomic significance occur in Thrace (Petrota, Pentalofos, Lefkimi, Feres, Skaloma), and on some Aegean islands (Thira, Polyegos). Less important occurrences exist on the islands of Lesvos, Milos, etc.34

Kaolin occurrences, formed by hydrothermal alteration of volcanic rocks, are widespread in Greece, e.g., Thrace, Macedonia, Lesvos, Milos, Kimolos, etc.17,20,24,53 Due to their origin, they usually form veins in altered volcanic rocks. Their composition varies widely, and usually they are not of good quality as they contain Fe, S, silica and other impurities. Deposits of hydro-thermal alteration of volcanic origin have been exploited in the past on the islands of Milos and Lesvos.

Bentonite deposits may be formed either by diagenetic alteration of volcaniclastic rocks, or by hydrothermal alteration. Large bentonite de-posits occur on Milos Island. Less important oc-currences and deposits also exist on the islands of Kimolos, Chios, Lesvos and Samos, and in Thrace.3,4,20,35

Feldspars: Large deposits of volcaniclastic rocks, rich in secondary K-feldspar, have been located in the area of Vani on Milos Island. The K2O percentage of the rock is of over 10%, and Fe2O3 varies from 1 to 2%. Beneficiation stud-ies, carried out by the I.G.M.E., produced con-centration of potassium feldspar with less than 0.1% Fe2O3, and barite as a by-product.28

Silica, amorphous (opal) or microcrystalline quartz, formed by hydrothermal alteration of volcaniclastic rocks, occur on the island of Milos,14 as well as in other areas with intensive post volcanic hydrothermal activity.

3.1.3. Mineral Occurrences Related to Contact Metasomatism

Wollastonite is usually a product of contact



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].



metasomatic reactions, forming exoskarn or en-doskarn deposits at the contact of marble and intrusive rocks. Known skarns, with important wollastonite outcrops, occur at Panorama near Drama, as well as in the area of Kimeria village, near Xanthi; estimated reserves in these areas are around 500 and 700 thousand tonnes, re-spectively.10,11 The Panorama wollastonite de-posit contains more than 50% wollastonite, and is possibly suitable for filler in ceramics, some metallurgical applications, and as a partial sub-stitute material for asbestos in the asbestos-cement industry.

Garnet prospects are mainly developed by me-tasomatic reactions near the contact of acid in-trusives and calcareous rocks, and in metamor-phic rocks. On the island of Serifos, significant occurrences of garnetite, suitable for abrasives and liquid filtering, have been located. The esti-mated reserves are around 1.5 Mt, with possibly 400-500,000 tonnes of exploitable garnetite un-der open pit conditions.37 Large garnet pros-pects also occur at Panorama, and in the area of Kimmeria, near Xanthi. The resources of gar-netite of andraditic composition of the Kimmeria prospect are estimated at about 1 Mt.16 Labora-tory and mineral processing tests, carried out within the framework of an E.U. funded project, showed that the Xanthi garnet is suitable for sand blasting in metal finishing.32

Talc and Soapstone occur in metasomatic zones that have been developed mainly at the contacts of serpentinised ultramafic bodies and surrounding gneiss or schist in Chalkidiki (Vertiskos Unit) and Organi-Myrtiski-Chloi (Rhodope Zone).6,35,57

Vermiculite prospects of some significance are located along the tectonised serpentinite-gneiss contacts in the Vertiskos Unit (Chalkidiki).7,58

Magnesite deposits of cryptocrystalline type are developed in veins, stockwork, or irregular masses, hosted in ultramafic rocks. Major de-posits occur in the Chalkidiki peninsula (Vavdos, Gerakini) and on the island of Evia (Mantoudi, Limni). Less important outcrops exist on Lesvos Island and in the areas of Ermioni and Kozani

on the mainland.5,12

3.1.3. Mineral Occurrences Related to Metamor-phic Processes

Kyanite is hosted in Al-rich rocks, metamor-phosed under Barrovian upper amphibolite fa-cies conditions. Minerals of the sillimanite group are common constituents of metamorphosed rocks in Rhodope.35 Non-economic kyanite out-crops have been described on the islands of Thassos and Naxos.30,42

Graphite: Flake and microcrystalline graphite outcrops occur in gneiss, schist and marble, of the Rhodope Zone (Thermes, Polyneri), in the Serbomacedonian Zone (Vavdos), as well as in the Circum-Rhodope Zone (Makri). In the area of Thermes (Xanthi Prefecture), a flake graphite outcrop has been located with estimated re-serves exceeding 600,000 tonnes of ore, and a graphite content of 3-12%.9,41,54

Quartz: Significant quantities of vein quartz, suitable for the ceramic and glass industries, are hosted in gneiss and schist in the Rhodope, Serbo-macedonian, Circum-Rhodope and Pelagonian Zones.1,16

Chrysotile asbestos, formed under low grade metamorphic conditions in entirely serpen-tinised dunite, in the Zindani area (near Kozani) has been mined till lately.44 The mining activi-ties in the area ceased in 2003. The use of as-bestos is entirely forbidden in all European Un-ion countries, since 2005, according to Euro-pean Union legislation.47

Emery, called “smyris” (“σμύρις”) by ancient Greeks, “naxium” by the Romans (from Naxos Island where it was originally mined) was pro-duced since the Classical Greek Era on the is-land of Naxos. The ancient mines are located on the northern part of the island in the area of Koronos. The deposits form lenses of variable size, and were formed by metamorphism of pre-existing bauxite deposits. Bauxites were meta-morphosed to diasporites at lower tempera-tures, and corundum-rich rocks at higher tem-peratures, during the Caenozoic.49


3.2. Exogenous Type Industrial Mineral Resources

Gypsum-Anhydrite: Extensive gypsum-anhydrite deposits of Permo-Triassic and Neo-gene age have been located in western Greece (Zakynthos Island, Aitolia-Akarannia, Thesprotia, Peloponissos) and on Crete Island (Sitia and Hania).19,39,40

White carbonates include calcium carbonate, dolomite and huntite. Filler grade calcium car-bonates, derived mainly from pure white friable microcrystalline limestone (on Kephallonia and Zakynthos islands), dolomitic and calcitic lime-stone and marble (Korinthos, Kavala, Thassos Island, Vermion).33 Dolomite is widespread in Greece, but production is restricted. Huntite de-posits occur in the Upper Neogene lacustrine formations of the basin in the Kozani–Aiani-Servia area, associated with other Mg-rich car-bonates, mainly hydromagnesite and magne-site.52

Palygorskite, Atapulgite: Large size and high quality palygorskite deposits, originating proba-bly by diagenetic transformation of pre-existing sandy smectitic material, have recently been discovered in the Ventzia basin (Western Mace-donia).27

Phosphate occurrences of Jurassic and Late Cretaceous age, exist in the Ionian and Parnas-sos Zones.51 Occurrences of phosphates in Neo-gene sediments also exist on the islands of Crete and Kefalonia and in Thessaly.45

Diatomite: Several occurrences, formed in lacustrine or marine environments, have been located on the islands of Samos, Crete and Za-kynthos, and in the Kozani area, etc.46

Borate minerals, colemanite-ulexite have been recognised in lacustrine sediments in Karlovassi basin (Samos Island).15

Rock Salt, is a chemogenic rock,14 formed by evaporation of saline water of various origin. Rock salt has been mined occasionally, in the near past, from Monolithi area, Ioannina Prefec-ture. About 95 Mt of salt containing around 80% NaCl, has been discovered by the

I.G.M.E.50

Silica, Quartz and Quartz-Feldspathic Sand, occur at various places in Greece. They may have been formed by weathering of (a) meta-morphic rocks in the areas of Evros, Serres and Kastoria; (b) granite in the Sithonia-Kassandra areas of Chalkidiki peninsula, on the island of Ikaria in the Aegean Sea, etc.; (c) cherts in the External Hellenides (e.g., area of Velika in Messinia).9,25,26,31,56,59 In most cases, sands con-tain considerable amounts of feldspars, or other impurities, making them suitable only for con-struction applications. In the area of Argos Orestiko (Kastoria) a silica sand deposit has been discovered, with total estimated reserves of over 1.2 Mt. Beneficiation tests on the latter deposit produced concentrations with 92-94% SiO2 and 0.04-0.08% Fe2O3, suitable for the ce-ramic and glass industries.56

The weathering of Palaeozoic leucocratic or-thogneiss, formed the residual type kaolin de-posits that occur in the area of Lefkogia, near Drama. The intense kaolinisation of either sodic plagioclase or K-feldspar precursors is associ-ated with large tectonic fault lines, which de-lineate the Lefkogia graben.38,48

4.4. INDUSTRIAL MINERAL MAIN CENTRES INDUSTRIAL MINERAL MAIN CENTRES OF PRODUCTION OF PRODUCTION

The most important production centres of In-dustrial Minerals in Greece are the Aegean sea islands of Milos, Yali and Crete, and many other locations in northern and western mainland.

More specifically, bentonite, perlite, pozzolana, kaolin, and silica are extracted from various de-posits on Milos Island. Most of the perlite pro-duction, and all of bentonite output, come from Milos, while kaolin is currently extracted from two deposits, operated by one company lo-cated on Milos Island. Perlite is also extracted from Yali Island, which is the only, and most important exploitation centre, for pumice. Poz-zolana is extracted also from the Skydra region in Northern Greece.

The most significant gypsum production centre



is the Altsi deposit in Eastern Crete. Periodically, minor quantities are extracted from the Stomio deposit (western Crete) and Zakynthos Island (Ionian Sea). The Katouna deposit in Western Greece produces gypsum for other than cement uses.

The only magnesite operation and plant are lo-cated at Yerakini, Chalkidiki region in Northern Greece. One company operates the two active mines of huntite at Neraida, Kozani area in North-Western Hellas.

One company in the Kozani region, North-Western Greece, operates three deposits of at-tapulgite. The company has also a processing plant in the nearby region of Grevena.

The small-scale production of olivine is derived from the Skoumtsa deposit, Grevena region, North-Western Greece. One company extracts, from various small deposits in Northern Greece, quartz and sodium-feldspar.

Stonewool products are produced by one com-pany in the area of Terpni (Serres). The raw material mainly consists of amphibolite, with minor amount of limestone and bauxite.

Finally, Kefallonia Island with the deposit of microcrystalline limestone, operated by one company, is the most important exploitation centre of filler grade white calcium carbonates. Residues stemming from the white marbles’ ex-ploitation in the Veria, Drama, and Kavala re-gions in Northern Greece, as well as in Attiki, are currently used as a significant source for filler grade white carbonate raw materials pro-duction. Dolomitic marble from the Korinthos area is additionally used as raw material for filler grade white carbonate production.60,61

5.5. KEY CHALLENGES FOR THE KEY CHALLENGES FOR THE INDUSTRIAL MINERALS SECTOR INDUSTRIAL MINERALS SECTOR

Industrial Minerals, and derived processed prod-ucts, are fundamental constituents of various fields of modern life, including such industries as construction, chemical and fertiliser, ceram-ics, paper, plastics, as well as in agriculture, environmental protection etc. In addition, tech-

nological developments are increasing further their consumption by expanding the fields of their application. Although minerals are non-renewable resources, it is not anticipated that there will be any shortage of mineral resources in the foreseeable future.

As the geological structure of Greece favours the formation of a wide variety of Industrial Mineral occurrences/deposits, and in view of new technological developments, prospecting for new, or re-evaluation of old deposits, should continue in order to assure a continuous devel-opment of the industrial mineral sector. Apart from the exploration efforts, perspectives for further development of the sector should broadly address the following issues:

• Sustainable exploitation of industrial minerals through the development of new and/or envi-ronmentally friendly technologies;

• The taking of measures to decrease environ-mental and social impacts (focus on extrac-tion and processing, minimisation of pro-duced waste);

• Utilisation of by-products derived from min-ing-processing operations;

• Increase efforts for market penetration and development of new products, and

• Intensify efforts for quality improvement and innovation.


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32. Lambrakis, D. & Panagopoulos, K., 2000. Evaluation of Hellenic Industrial minerals as blast cleaning abrasives for sandblasting. Technical Chamber of Greece, Proceed-ings of 3rd Congress on Mineral Wealth, Vol. Α, 579-588.

33. Laskaridis, K., 1994. Greek white calcitic marbles. In-dustrial Minerals, April 1994, 319, 53-57.

34. Marantos, I., 2004. Study of the Tertiary volcanic rocks alteration in the Feres basin of Evros Prefecture, empha-sising on the genesis of zeolites and their possible appli-cations. Unpublished Ph.D. thesis. Technical University of Crete, Department of Mineral Research Engineering, Chania, Greece, 264 pp.

35. Marantos, I. & Kosharis, G., 2003. Industrial minerals and rocks in the area of Eastern Macedonia – Thrace, Greece. Researches, results and prospects. In: I. Anas-tasiadis (Editor) Proceedings of 50 years anniversary of Geological Society of Greece, 77-88.

36. Matarangas, D. & Triadafyllidis, E., 2005. Geological map of Greece. Scale 1:1000000. I.G.M.E. digital map.

37. Papastavrou, S. & Perdikatsis, V., 1991. The garnetite from Serifos. Bulletin Geological Society Greece, 35(2), 291-300.

38. Papoulis, D. & Tsolis-Katagas, P., 2001. Kaolin deposits of Lefkogia, Rhodope, Greece: process of kaolinization. Bulletin Geological Society Greece, 34(3), 875-882.

39. Pitsikas, L., 1991. Gypsum deposits of Zakynthos Island. I.G.M.E. Internal Report, 24 pp.

40. Pitsikas, L., 1992. Gypsum Triassic deposits of Aito-loakarnania Prefecture. I.G.M.E. Internal Report, 26 pp.



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E V E N T S :E V E N T S : 3232ndnd International Marble Exhibitio International Marble Exhibition n

M A R M I N S T O N E 2 0 0 8 M A R M I N S T O N E 2 0 0 8 (21/2/2008 (21/2/2008 –– 24/2/2008 24/2/2008))

International Exhibition Centre HELLEXPO, Thessaloniki

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 and Benefits for the Quarrying Activity, in Compliance with the Environment. 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.

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 Mineral Processing.

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 General Director of the I.G.M.E., Prof. A.N. Georgakopoulos

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, Aggregates and Marbles Extraction Residues—

Techniques for the Exploitation of Abandoned Quarries”

The Deputy Minister, Mr. S. Kalafatis

From Left to Right: Dr. D. Bitzios (I.G.M.E.), Prof. A. Tsirambidis (AUTH), Dr. C. Katirtzoglou (I.G.M.E.), Dr. A. Hatzikirkou (I.G.M.E.)

I.G.M.E.—Exhibition booth

The above lectures, in Hellenic, will be accessible via the websites:

I.G.M.E. (http://www.igme.gr) MARMIN (http://www.helexpo.gr)

I.G.M.E. ORGANISATION CHARTI.G.M.E. ORGANISATION CHARTI.G.M.E. ORGANISATION CHART

BOARD OF DIRECTORS

LEGAL SUPPORT SERVICES

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GENERAL DIRECTOR

DIVISION OF HUMAN RESOURCES

& ADMINISTRATION

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INTERNAL AUDITING OFFICE

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DIVISION OF INFORMATICS,

LIBRARY & PUBLICATIONS

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DIVISION OF PLANNING AND

DEVELOPMENT

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DIVISION OF FINANCE

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SUPPORTING

SERVICES

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APPLIED GEOLOGY

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RESOURCES &

ENVIRONMENT

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SECTOR OF MINERAL

RESOURCES &

EXPLORATION

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REGIONAL

BRANCHES

DIV. OF GENERAL

GEOLOGY & GEOLO-

GICAL MAPPING

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ING GEOLOGY

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WORKS

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RESOURCES

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DIV. OF MINERAL

PROCESSING &

METALLURGY

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DIV. OF MINERALOGY

& PETROGRAPHY

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DIV. OF MINERAL EXPLORA-

TION & PROJECT EVALUATION

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DIV. OF MINING

ACTIVITIES CONTROL

& CONSULTATION

SERVICES

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R.B. OF EASTERN

MACEDONIA & THRACE

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R.B. OF CENTRAL

MACEDONIA

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R.B. OF WESTERN

MACEDONIA

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R.B. OF EPIRUS

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R.B. OF CRETE

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R.B. OF

PELOPONISSOS

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GENERAL DIRECTOR’S OFFICE [email protected]

DIV. OF

HYDROGEOLOGY

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DIV. OF GEOTHERMAL

ENERGY & THERMAL-

MINERAL WATERS

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DIV. OF GEOCHEMISTRY

& ENVIRONMENT

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DIV. OF

HYDROLOGY

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Documents

March 2008 - IGME · March 2008 Institute of Geology and Mineral Hellenic Geosphaera Exploration (I.G.M.E.) ... Spirou Loui, str. Olympic Village, Entrance C 136 77 Acharnae Tel