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Gaize: An untapped resource of Lithuania

2014-07-07

The only field of gaize, valuable rock, in Lithuania is situated in Šilutė district. The field has been abandoned for 20 years. Explored and forecast resources of this field are in the region of several dozen million tonnes. The production of this rock could offer economic, environmental and social advantages to Lithuania.

Gaize is a rock dominated by amorphous (opalescent) silicon dioxide which has active hydraulic properties. These properties make it most suitable for the production of Portland cement: a 10–15% gaize admixture binds calcium hydroxide which is released by hardening cement to insoluble calcium silicate hydrate.

The only gaize field in Lithuania is related to the upper sediments of the chalk santonian layer. More than 40 years ago, the Stoniškės gaize field in the south western part of Lithuania in Šilutė district situated on two neighbouring sites of Žemaitkiemis and Stoniškės (located 700 m apart) was explored.

The Žemaitkiemis site was put into operation but was abandoned in 1994 due to the general weakening in the demand for building materials. Only 0.7 million tonnes of gaize was excavated on this site. The remaining reserves are 15.9 million tonnes. Moreover, the neighbouring Stoniškės site has gaize deposits of 17.8 million tonnes. The reserves of the Žemaitkiemis site can be increased by the forecast resources (24 million tonnes) located nearby. The reserves may also be increased depthwise but this method is not viable due to more complex excavation (especially hydrogeological) conditions.

Gaize from the Stoniškės site was mostly used for the production of Portland cement as an active hydraulic admixture replacing pozzolan which used to be imported from the Bryansk area (Russia).

Rock

Average values, %, from–to

SiO2

Al2O3

Fe2O3

CaO

MgO

SO3

Hydraulic activity

Gaize

63.5–73.2

1.0–2.1

0.3–1.0

6.0–17.3

0.4–0.5

0.2–0.4

165.0–226.1

Silica marl

24.6–57.4

1.9–4.2

1.3–2.6

17.8–37.3

0.6–1.4

0.0–1.3

148.7–305.4

Carbonate gaize

37.3–64.4

1.7–4.1

1.0–2.4

16.6–31.5

0.3–0.9

0.1–1.0

193.9–304.1



Chemical composition of the effective layer of Stoniškės field
Experiments have shown that gaize has much broader application as it can be used for the production of pozzolan Portland cement,
decorative cement, lime and gaize binder, silicate bricks, porous concrete and synthetic wollastonite. The demand for the latter has been growing strongly worldwide but the possibilities of gaize synthesising need further analysis.

“Studies have shown that the forecast reserves of gaize in Lithuania are several million dozen tonnes. It is a huge asset which has not been used so far. If more investors showed interest in the production of this rock, it would be definitely beneficial for the Lithuanian economy”, said Vice-minister of Environment Daiva Matonienė.

For more information about gaize, please contact Vytautas Antanas Januška, Head of the Division of Underground Resources, Lithuanian Geological Survey, tel. (8 5) 213 3436, email vytautas.januska@lgt.lt

Public Information Division
07/07/2014


Minister of Environment of Lithuania Kęstutis Navickas
Minister of Environment of Lithuania Kęstutis Navickas