The main reason for the acquisition of MEVIOR's plant were the provided opportunities for further Research and Development in the field of Industrial and innovative Minerals, who had already been a field of Research and Development for the founder and sole shareholder of Olympus S.A. Another reason was also the R & D of other materials and industrial by-products that have not yet exploited in our country.

Few of them are: clay diatomite of Elassona, pozolan of Pella, zeolite of Evros, graded dry pumice and quartz which produced from quarries and recycling both.

Clay Diatomites

By the total area of 65 acres, property of G. Georgiadis, 33 acres of them have an exploitation license and the rest have all the required prerequisites to be licensed also. The consecions will allocated in Olympus S.A.

The clay diatomite of Sarantaporo, Elassona basin, part of which is the mentioned area, have been extensively studied geologically, but industrial research (in semi-industrial scale in pilot - plant), for the production of products that will appeal for specific uses were lacking.

Greek clay diatomite of Olympus S.A. in electron microscope

Greek clay diatomite of Olympus S.A. in electron microscope

Exploratory excavation of diatomite in Elassona

Exploratory excavation of diatomite in Elassona

Research for the possible uses of Greek clay diatomite have only done at laboratory scale. It should be noted the extensive work of the Geological Department of Athens University and Professor M. Stamatakis in order to produce lightweight aggregates (Light Weight Aggregates) by participating in several European Research Projects.

The diatomite of the mentioned area consist of discoidal and cylindrical diatom shells which consists of amorphous SiO2 (Opal-A), clays of the smectite and illite group, with diatomite to clays ratio of about 60/40 (which ratio after air seperation increased to 75/25). A typical chemical analysis and SEM photograph is available.

Extensive research excavations have been done in the licensed area of 65 acres. Also, and drillings have been done by other organizations in the wider area and they reported for a 40m thick of aluminous diatomite, estimating reserves of 4,000.000 tonnes for the property.

The industrial research was based on the main characteristic of the thermal processed at 800 oC diatomite product which is the low bulk density related to the porosity. Thus research focused on the possibility of producing a heat insulating lightweight building element and an absorbent material.

The research for lightweight aggregate (Light Weight Aggregates LWA) had already been done by the University of Athens on a laboratory scale as mentioned above.

It should be mentioned that Danish clay Diatomite (Fur island) has similar main characteristics with the Greek one (Olympus Minerals diatomite product) is used on both types of uses, the production of heat insulating components and the absorbent, mainly for exports.

Industrial research which have done concerning glazed building elements, was a comparative evaluation of similar market products which were the Ytong's and Porotherm's bricks. Carried out by National Interuniversity Research Institute of silicate Lands and Materials in Mons, Belgium (Institut National Interuniversitaire des Silicates, Sols et Materiaux) and funded by G. Georgiadis. (The research is originally submitted below).

After extensive measurements determined the optimum firing temperature (900 C) where a change on the view of diatoms will happened above it (blurriness) despite that its structure is not affected dramatically as it is depicted in the microscopic photographs (x1000) Thus, the strength of the specimens is almost doubling, but also to increase the density of the specimens with an adverse effect on the thermo-sound insulating properties.

The comparative evaluation which is based on the thermo-sound insulating properties of the products, classifies Olympus diatomite between the two products of Ytong and Porotherm (fired at 950oC - approximately equal energy) and based on their compressive strength superior of both of them.

SEM photograph after the firing

SEM photograph after the firing

Pictures taken by optical microscopy (x1000) in different temperatures of firing

Pictures taken by optical microscopy (x1000) in different temperatures of firing

The Industrial Research for the production of absorbent made on pilot-plant scale at the Centre Technologique International de la Terre et de la Pierre in Tournai, Belgium on a representative 20 tonnes sample from the concession quarry of OLYMPUS company and funded by G. Georgiadis.

The research provides with all the required data for the creation of a plant that will produce absorbent diatomite granules. Particularly, provides with info about the crushing conditions the percentage of the smaller granulometries which removed after the sieving, before the entrance of the material in the rotary kiln, the firing conditions (temperature), the exhaust flow, the fuel consumption per ton, the firing loss, the final classification, etc.

The produced material was evaluated by the French Geological Institute (BRGM) and compared with Diatomites from Denmark and China and as absorbent with attampoulgiti and montmorillonite in accordance with applicable standards. The result of the comparison as is depicted in the relevant table of BRGM, proves that only the Chinese Diatomite is superior in absorbency than the Greek one which outweighs all the others.

A paper about the clay diatomites of Olympus Minerals have been submitted in the International Conference for Industrial Minerlals in Athens in 2008 from G. Georgiadis, M. Stamatakis and K. Chtzicharalambous. Concluding about the two possible uses of the Greek diatomite of Olympus Minerals which have studied were: a) as thermal - sound insulating blocks and lightweight aggregate (LWA) b) as industrial absorbents. According the current situations of the market the first use, because of the high energy prices in comparison with the prices of other products for similar uses on the world market, it cannot be a sustainable investment.

On the other side, the creation of a unit for absorbent due to the much higher price of the final product in relation to the previous mentioned use and the almost equal energy consumption (both fired approximately in 800oC - other processes cost is approximately equivalent), it is absolutely a sustainable investment (considering that the produced material in semi-industrial scale was a high quality material).

Another research was carried out by the Italian firm "LAVIOAS" about the use of the material as cat litter. The results of the research (depicted in the following table) were acceptable except the factor of clumping, which may be solved with micropeletizing of the material. Olympus Minerals, shall consider the possibility to install a new micropeletizing unit, aiming to produce a pelletized product of diatomite - zeolite mixture as cat litter and micropeletizing of superfine zeolite with addition of soil conditioners.

The following table depicts the results from the mentioned research about the usage of the Greek diatomite of Olympus Minerals as cat litter.

DATA / DATE 25-08-11
PRODOTTO / PRODUCT NAME diatomite grecia
UMIDITA (%) / MOISTURE (%) 6,65
2,36 51,79
0,5 << 0,85 46,61
FONDO 1,60

Due to the circumstances, the investment for the installation of an absorbent unit was not possible. Therefore, the company has recently started to produce diatomite products which are useful in agriculture (spraying, dusting, ingredient in soil conditioners as a source of amorphous silica) and as an insecticide. This venture achieved because of the possibility our company has to produce ultrafine products under -20 microns.

The same time the research on air separation achieved separating unwanted materials (quartz, clay agglomerates, etc.) resulting in the production of much cleaner diatomite products.

The following picture in electronic microscopy were carried out by the Chemical Process Engineering Research Institute of CERTH (Samples 1X,unprocessed sample, depicted in Photo 1 & 2). The samples which are processed in air separation of very high speed shows luck of foreign coarse particles (quartz, clay agglomerates) (Sample 1Y, depicted in photo 3 & 4).

Sample 1X (magnification x700)

Photo 1

Sample 1X (magnification x700)

Photo 2

Sample 1X (magnification x700)

Sample 2Y (magnification x700)

Photo 3

Sample 2Y (magnification x700)

Photo 4

Sample 2Y (magnification x700)

After the success of the mentioned process, the production of products which can be used as insecticide, in agriculture as a source of ultrafine amorphous silica, as superfine filler of -20 microns for various industrial uses where superfine amorphous silica required, is possible.

Concerning the use of Olympus minerals diatomite as insecticide, tests have been done in the Diatomite Institute of Canada. The research was for the use of diatomite as insecticide for ambulatory insects that grow mainly in the grain silo.

The following table depicts a comparative evaluation between different types of Greek diatomite with a reference sample (MN51) which regards mortality usually developing within silos grain insects (Sitophilus ozyzae, Tribolium castaneum). Granulometry of the produced product of -20 microns is depicted in the attached table and diagram. The measurement was made using LASER by CERTH institute.

Photograph from the electronic microscope (SEM).

Pozzolan of South Pella

The pozzolan deposits which have found in South Pella covered the needs of TITAN S.A. Cement Factory in Thessaloniki for four decades.

Olympus S.A. has already produces pozzolan of -45 microns (crushed, dried, milled in Pebble mill and air separated) for the needs of the Archaeological Service and for Roman Connie application.

After the installation of the high speed air separator and the necessary filter, Olympus S.A. can produce superfine pozzolan (-20 and -10 microns) for special uses. The hyper-milled - superfine pozzolan of -10 and -20 microns of Olympus Minerals (See grain size analysis with LASER - compared with the known Super-pozz) is suitable for specialized uses such as specialized cement putty for precision fillings and dam repairs, tunnels, sewage systems and generally microcrack seals for soil sealing ( The pozzolanic reaction ability (binding capacity of Ca (OH)2) increases in proportion to the specific surface area and inversely proportional to the grain size.

The use of superfine pozzolan is recommended for the prevention of cracks in cement due to non commitment of the released Ca(OH)2 during cement hydration and contraction.

Also, it is recommended for uses such as self-leveling floor screeds and self-compacting concrete.

The monitoring of the granulometry of superfine products using LASER carried out by CERTH (National Technology and Development Center) in Thermi, Thessaloniki.

It is important to note that while there are several plants in the country producing superfine soft minerals (calcium carbonate, etc.) the Olympus plant is the only capable plant for the production of superfine hard minerals (> 6 Mohs).

Pozzolan quarry

Pozzolan quarry

Comparative evaluation of the granulometry between SuperPozz, flying ash and Silica fume

-10 microns (D90) particle sizing


The most know area for zeolites in Greece is in the North part of Evros Prefecture. The zeolites extends also to the Bulgarian territory where an exploitation has already began by a Greek company which now has redeemed by a large multinational company while on the Greek territory no exploitation is existing. The only known effort that made for exploitation of the Greek zeolite was made by a Greek company in the past but after legal disputes the company couldn't acquire the final concession of the area to proceed in the desired exploration and exploitation. It should be noted the long, extensive and successful research on the applications of Greek Zeolite, which has made by Professor of Geology Mr. A. Filippides in the Aristotle University of Thessaloniki.

OLYMPUS S.A. after geological studies in the mentioned area has found another new area of interest, outside from the vindicated area. For this new area of 99,5 acres in Kokkalo area, which exist in the near vicinity of Petrota village of northern Evros, OLYMPUS S.A. applied for an exploration license which finally get it. In this area, based on the approved technical study by the Ministry of Environment, Energy and Climate Change, a road of 1450 meters long was excavated, which covered the whole licensed area.

Aim of this road was mainly the access to the areas where exploratory excavations where planned to made and also the geological exploration of the main part of the area.

Zeolite (Clinoptilolite) photograph from the electronic microscope (x 4000)

Zeolite (Clinoptilolite) photograph from the electronic microscope (x 4000)

The results of the exploration were encouraging with the detection of a stratiform zeolite deposit, with an average thick of 33 m. approximately and length of 300m. at least. The deposit was confirmed both by the exploratory.

The whole area had dense vegetation and there were not many zeolite occurrences. Geological - mineralogical mapping (scale map in 1:100) of the area was made. Based on the geological mapping, a dense rock chip sampling was made also.

The samples were analyzed by specialized laboratories in U.S.A. and U.K. [The Mineral Lab – COLORADO (XRD), Hazen Research Inc. – COLORADO (CEC), Intertek Wilton UK, (ICP-MS) etc.]. On these laboratories, mineralogical analyses and cation exchange capacity (CEC) were made. The results from the mentioned analyses were absolutely encouraging (Clinoptilolite content ranges from 80 to 86%).

Beyond laboratory research, which is ongoing, transferred representative quantity from different parts of the ore body to study the processing on an industrial scale in the company's plant in Assiro Thessaloniki.

Under this research trial quantities of various granulometric sizes were produced, especially ultra-fine products (D90= -20 microns and D90= -45 microns). The production putted on the market with fully satisfactory results by the use of it.

It is important to note that for the first time in Greece research about the enrichment of zeolite with clinoptilolite based on air separation after the milling of sample in a pebble mill is in progress.

The importance of this research for zeolites of Evros is generally great because it opens the way to become marketable and poor parts of the zeolite deposits.

The mentioned research was made in a concession which recently licensed by the Ministry of Environment & Energy (License Reference Number ΔΜΕΒΟ-Β/Φ6.11.7/171440/315/20-02-2017 με ΑΔΑ: ΩΙ704653Π8-ΕΟ8), after the tenancy of the area by the Decentralized Administration of Macedonia and Thrace. The quarrying activity will be developed in three separate parts of the zeolite deposit,in the total concession of 83,4273 acres. The method by which will be exploited the deposit, is the horizontal surface excavations method, which will began from the level of the existing road, which was opened for the exploration. The exploitation will take place gradually according to the schedule of approved studies (Environmental Impact Study and Technical study) and will extend in 11 acres in the first 7,5 years. After the exploitation which can last for 15 years, as the duration of the exploitation license.

The exploitation will be done in four separate open excavations in a total area of 22 acres (almost 26% of the concession area). After the exploitation each excavation will be restored immediately with the appropriate planting. Based on extensive experience in the design and operation on industrial mineral exploitation in Greece, OLYMPUS S.A. is able to fully guarantee the rational exploitation of the deposit with the least possible impacts to the environment.

In "Mavri Petra" area which in 2 Km western of "Kokkalo" area an exploration license has received from the Decentralized Administration of Macedonia - Thrace (Reference License Number: 31539 (2015)/Φ27.112/10-05-2016 with code ΑΔΑ: Ω1Τ1ΟΡ1Υ-6ΧΒ). Research was planned to made with excavations for representative sampling in order to determine the geometrical and quality characteristics of the possible deposit. The first chip rock sampling that have been done from the surface zeolite occurrences where performed in chemical and mineralogical analysis in order to determine the physical and chemical characteristics and also the quality of the zeolite samples. The results from the laboratory tests were absolutely positive Zeolite samples from the exploration research will be studied in terms of mineralogical, chemical and physical characteristics in foreign laboratories.

The initiation of the above research and exploitative work are expected before May of 2017.

Graded Dry Pumice

Noting the lack of market in graded dry pumice in different granulometric fractions and in milled dry pumice (-45 microns) Olympus S.A. already offers to the market the above products. The raw material comes from Yali on Nisyros Island and can be used for construction purposes and for many other known uses. Some of the most known are for the drinking water treatment, waste water cleaning, in pretreatment for reverse osmosis in the desalination of seawater (SWRO), in the filtration of the farm wastes, as a source of SiO2 in agriculture, in cosmetics etc.

Especially for the paint industry and as filler - extender Olympus S.A. has -20 microns granulometry.

Regarding the construction sector have been made some very interesting studies in the Laboratory of Building Materials of AUTH. The conclusions can be found on our site.

  • Checking cement as pozzolanic material with the ASTM standard C593-95 and EN 450-1 with lime and replacing cement respectively.
  • Mortars with inert materials inert pumice in which a 10% It was replaced with silica sand (0-1) mm and cement mix CEM42,5 + 25% pumice powder. The percentage of silica sand 10 % total aggregate added to normalize the grading curve in order to be in desired area.

The possible grain sizes are available after communication:

In powder formIn granular form
0 - 200 microns 0,1 - 0,3 mm
-45 microns 0,1 - 0,4 mm
-20 microns 0,2 - 0,5 mm
0,4 - 1,0 mm
0,8 - 1,3 mm
1,2 - 2,4 mm
2,0 - 3,5 mm

Testing as pozzolan cement with lime according ASTM C593-95 standards.

CompositionTestBending Resistance σKCompressive resistance σθ
Pumice 7 days 0,820 8,5
Pumice (α) 28 days 2,820 9,3
Pumice (β) 28 days 2,830 9,2

Required StrengthASTM C593-95
7 days 4,1 MPa
28 days 4,1 MPa

Εικ.3,4: Διαγράμματα καμπτικών και θλιπτικών αντοχών

Photo 3, 4: Bending and compressive strength charts

Testing of cement as pozzolan with cement according EN 450-1

CompositionTestBending Resistance σKCompressive resistance σθ
Reference 7 days 7,39 19,72
Pumice 7 days 6,55 19,70
Reference 28 days 7,31 25,30
Pumice 28 days 8,90 30,30
Reference 90 days 7,39 32,80
Pumice 90 days 7,06 25,64

Εικ.4,5: Διαγράμματα καμπτικών και θλιπτικών αντοχών

Photo 4, 5: Bending and compressive strength charts

Pumice composition as an inert
MixCementPumiceSand (0-1)WaterSpread
gr gr gr ml cm
mix1 500 450 50 270 16

Pumice composition as cement and inert
MixCementPumice (Cement)Pumice (inert)Sand (0-1)WaterSpread
gr gr gr gr ml cm
mix2 450 150 540 60 300 16

mix1 7 days 4,263 34,078
mix2 7 days 3,695 31,118
mix1 28 days 4,125 28,470
mix2 28 days 3,709 40,439

Concluding, about the mortars with thermal and sound insulating properties should be mentioned Hess's LimeStrong which is one of the most known in the US ( It is a simple mixture of finely ground pumice + water without cement, applicable for external insulation plaster with low cost and ability to add color and choice of textures (coarse, fine). It is a simple mixture of fine grained pumice + water without cement, which is used in external insulation plaster with low cost and with the ability to add color and choice of textures (coarse, fine).

Beyond the fine grained pumice (-45 microns) which reacts with hydrated lime pumice in thicker granulometry 0-2mm and participates as inert to the above mortar.