Nissiros volcano emerged from the sea 200,000 years ago to form a cone of land. As it continued to erupt over the following years, molten fragments of stone were released in the atmosphere, only to cool down again as they fell on the ground to eventually form layers of volcanic ash.
There are five calderas on Nissiros island. “Stefanos”, 260 metres wide and 30 metres deep, is one of the largest and best preserved hydrothermal craters in the world.
The volcano’s latest big eruption dates back to 1888, while a smaller one took place in 1933.
LAVA Mining & Quarrying was established in 1952 to operate the pumice stone Municipal Quarry located on Yali island to the north of Nissiros. The company was integrated into Heracles Group in 1977 and began expanding to new activities in 1980 by acquiring the Gypsum Quarry at Altsi, Sitia. In 1989, LAVA began to operate the pozzolana rock quarry in Milos, while the silica sand quarry on the same island started operating in 1996. In 2001, HERACLES Group becomes a member of Lafarge Group, present in 64 countries and worldwide leader in building materials. From 2002 until 2011, LAVA developed aggregates trading in its unit in Almyros, Volos.
Pumice Stone Quarry (Yali)
The pumice stone quarry is located on Yali island, to the north of Nissiros. LAVA has been operating the quarry, owned by Nissiros Municipality, since 1952. This opencast quarry is operated using the method of vertical benches.
How the pumice stone quarry operates
Initially, there is an uncovering of the deposits from the overburden sterile geological formations (8-25m). The quarrying is done with bulldozers and the quarried material is driven to the processing installations through belt conveyors.
Processing consists of granulometric gradation of the material in circuit of static and vibrating sieves and a crushing of a minor part.
3. Deposit – Trading
The final products (variably-granulated pumice stone) are deposited through belt conveyors in outdoor specially formed stockpiles. From there on, through tunnels as well as through a second series of belt conveyors the products are loaded into vessels and shipped to customers.
The quarry’s production capacity is up to 1,000,000 tons/year; it has privately-owned port facilities than can serve vessels with a tonnage of up to 27,000 tons at a loading rate of 1,000 tons/hour.
Pumice stone extraction, granulated fragments production and trading and bulk product loading into vessels are compliant with the requirements of ISO 9001:2008 standard.
Pumice stone qualities produced by the quarry are CE-marked according to ΕΝ 13055-1:2002 (Lightweight aggregates for concrete, mortar and grout) and EN 13055-2:2004 (Lightweight aggregates for bituminous mixtures and surface treatments and for unbound and bound applications) standards. For this purpose, the quarry is equipped with a laboratory conducting quality control of pumice stone as to its grading, moisture and specific weight.
Committed to sustainable development
The pumice stone quarry is constantly upgraded and improved on annual basis. Activities mainly focus on enhancing employees’ and contractors’ Health and Safety, reducing the environmental footprint and ensuring the quarry’s sound environmental management and operation, based on Sustainable Development principles. The commitment of the quarry’s people is essential for the success of the broader “Sustainability Ambitions 2012” project on sustainable development of Heracles Group.
Health and Safety: Top priority
Occupational Health and Safety of employees and contractors are fundamental values and key priorities in all LAVA’s activities. Like all other company facilities, the quarry has been applying Lafarge Group’s Health and Safety policy with zero accident target since 2006. Systematic efforts in the past few years have led to considerable progress and a continuous improvement in Health and Safety issues.The policy involves measures regarding equipment, use of Personal Protective Equipment, Standards and Procedures for all tasks executed and appropriate training programmes to foster a common understanding of a safe behaviour.
Improving environmental performance
Sound environmental management and the quarry’s upgrading are daily priorities. Under “Sustainability Ambitions 2012”, the quarry has been implementing a specific action plan that focuses on: reducing its environmental footprint by restoring the landscape (quarry rehabilitation), protecting marine biodiversity in the broader vessel-loading area (through anti pollution plans and Vessel Waste Management Plans) and recycling the batteries and lubricants of vehicles and equipment.
30.000 saplings have been planted for the quarry’s rehabilitation in the past years. Indigenous plants used in rehabilitation are grown in a nursery garden at Yali.
[ΠΗΓΗ: http://www.lava.gr/ ]