Since ancient times, there have been many methods for digging marble from mines. However, the most substantial development of mining techniques has only occurred over the past hundred and fifty years. Usually, marble mining techniques consist of several phases. The cutting phase is the phase where the “wall of excavation” of marble (the part of the mountain that can produce blocks of marble) is physically separated from the surface of the mountain. Before this can be done, the surface must be adequately prepared to reduce waste to a minimum and allow the development of the mine (which must follow the appropriate scheme in accordance with the mine typology) to continue on a regular basis. The proper cut area limitation is carried out according to the thickness of the mountain, the direction of cutting, the distribution of natural cracks from the rock, and the output of blocks that can be obtained from the mountain, as well as the continuity of the color and pattern of the marble.

Since Ancient Rome, when the exploitation of the Carrara mine began, cutting was carried out by a manual method that implies the separation of the marble bench wall from the mountain through fracture. The oldest technique is “tagliata”: the miners create cracks in the rock using a tool right where they find a crack or gap that already exists, to obtain a V-shaped cut line. Then the slit is forcibly opened with an iron plate, to get a gap inside which causes the separation of the marble bench wall. Another more rugged technique involves the use of pieces of wood: pieces of wood are placed in the cutting line and then moistened with water. The wood that loads makes the gap in the surface of the marble swell, which then breaks the marble and separates it from the mountain plate.

Manual techniques like the one above were used for centuries until finally gunpowder was discovered. Mine excavations with gunpowder were used massively until the beginning of the 20th century, allowing very large excavations in a relatively short time. The technique of “varata” (the name used for the separation of large mountain plates using gunpowder bombs), which has been used from the 19th century, is a very spectacular excavation technique to tell because of the amount of excavation that can be achieved.

To prepare varata several deep holes are made in marble. Inside the hole, a bomb consisting of explosive charges connected to the detonator was prepared. The part of the hole that remains empty (“borraggio”) is filled with sand or milled stones, to resist the impact of the explosion. A signal trumpet warns the diggers to take refuge, then the bomb is set off. The explosion made the bench wall slip because it was separated from the mountain, allowing the diggers to divide it into marble blocks.

The problem with the varata technique is the waste of material due to the explosion that destroyed the mountain. The miners then began to conduct more controlled explosions, with the cargo placed to get a more precise separation of the marble blocks (for example through the use of linear charges). Explosives are still used today, when it is needed to make the excavation area safe by removing a number of mine conditions that can pose a risk, or to facilitate the separation of marble plates that have been outlined by modern techniques.

In the 20th century, miners began abandoning the varata technique and began testing the “taglio” technique (cutting). This technique allows the diggers to get the marble slab which is described very precisely, which means that material waste will be very low. The first method is to cut with helicoidal wire: a wire about 5 millimeters in diameter woven with steel wire forms a helix. In wire grooves, water mixtures and abrasive materials are poured: wire, connected to the motor mill, strained and then skipped (the most innovative plant speed may reach fourteen meters per second) through marble along the cutting line. The use of helicoidal wire spreads quickly, also because it allows cuts of various types, lengths and directions.

The most modern method, as well as the most popular at the mine today, is cutting with diamond wire which was introduced in the late 70s at the Carrara mine. The principle is the same as the helicoidal wire method, but small steel cylinders called “pearls” are added in and covered with industry-specific diamond layers. This combination of ingredients can provide more efficient results thanks to its hardness.

There are also other cutting methods, though less popular, namely chain cuts which are carried out through the use of machines that have toothed chains passing through the stone. There is also a marble cutting cutter with toothed discs and water jet cutters that use high speed and high pressure water jets to cut.

Our miners in Italy use only the latest and most precise mining methods, so that the slabs produced are uniform in thickness. That means our marble are more durable marble with better aesthetics.

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