Granite blocks production is a process which has a lot of useless material. That aforementioned material was transported and taken away in debris places, but that provoked damage in the environment. In order to solve that inconvenient in 2002 we have run two sandstone classification and grinding plants, one in Cadalso de los Vidrios (Madrid) and another one in Porriño (Galicia).
Since those plants have been created, all debris and sterile materials are recycled and turned into diverse grain sizes of sandstone, which are supplied to concrete plants, terrazzo factories, building materials warehouses, etc.
The average annual production in these years is between 250,000 and 300,000 tons and the common products taking into account its grain size are:
- Artificial aggregates: 0/22.4 mm
- Sands: 0/4 and 0/2 mm
- Rolled gravel: 2/4 mm
- Gravels: 4/8 mm
- Gravels: 8/20 and 20/40 mm
- Loose stones: 40/70 mm
- Broken blocks: 40/300 mm
Certificates for sandstone construction done by Bureau Veritas:
- 0/4, 4/8, 8/20. 0/4, 4/8, 8/20. Norm UNE EN 12620: 2003 + A1: Sandstone for concrete.
- 0/4. 0/4. Norm UNE EN 13139/ 2003 y UNE EN 13139/AC:2004: Sandstone for mortars.
- 0/22,4. 0/22,4 Norm UNE EN 13242: 2003 + A1:2008: Sandstone for granular layers and layers with hydraulic conglomerating in order to use in firm structural layers.