Amis d'la Curma

Where We Are

The Colma Village

Colma Yesterday ...
... Colma Today

Angelo Morbelli

His restored atelier

People of Colma
Quarrymen and Mines


Colma Activity

The Restored Canvas

Quarrymen and Mines of the Colma


The mining of cornerstones from the mines


(by Anita Rosso)

The hill of the Colma has in its subsoil the cornerstone ("Pietra da Cantoni"), better (and improperly) known as "tuff": it is a fine grain, tender and friable marl and marly sandstone.

These marine rocks deposited, 15-20 millions years ago, at a relatively shallow sea depths. This sea occupied most of the Monferrato area; as a matter of fact, it is not difficult to find fossil shells or fish teeth in the blocks, used during the building up of the houses.

Many mines were opened; inside there the layer of "tuff" had a thickness of about 10 m and followed the outline of the hill; for centuries these mines supplied with building materials. The mines were formed by tunnels 5 m width , with a height of 5 m too. From the main gallery departed, perpendicularly, entry tunnels and other galleries which were parallel to the main one.

The galleries bays were 5 m width and between a digging out and the other there was another space left 5 m width too. The main purpose of this solution was for safety reasons: to avoid the collapsing of the gallery. Many digging outs, further to the extraction of the tuff, were filled in with recovery materials deriving from the squaring of the blocks.


wheel barrows out of a quarry

The dimensions of the blocks of squared "tuff", in vernacular named “canton”, were 50 cm x 25 cm x 15 cm, with a total weight of around 32 Kg.

They were used for the building up of houses and rural residences. The dimensions of the flat tiles (in vernacular, “pianeli”) were different, larger and higher but much thinner, with a weight of around 45Kg, used for the building up of ovens. 

Some mines are still visible, though by now neglected more than a half of a century ago.

Many were the professional quarrymen who worked in the digging out of the blocks of squared tuff, but many others were also the so called “seasonal workers” who worked in mines to provide for the needs of their families. These latest, in addition to the hard farm work they carried out this activity and, once mined and piled up, the "canton" were carried away with burrows dragged by horses.

More or less important mines were managed by the Angelino, Campagnola and Valleggia families.



the inner part of a quarry