Mineralogical locations
of Piedmont
by Patrizia and Massimo Deidda
Pellice Valley
Cave of Rorà-Comprensorio Bonet del Prete-Rorà (TO)

We are located in Luserna Valley either side of the Valle Pellice valleys radiating from the town of Luserna San Giovanni (TO) and more specifically in the high Valley of Luserna.

We arrive in the picturesque municipality of Rorà continuing the road up the Val Luserna after the municipality of Luserna San Giovanni.

Very interesting is the visit to the ECOMUSEUM Luserna stone-stone and the Quarrymen. ‘’

Beautiful and evocative in Bric, the public park.

The local economy is mainly based on extraction of Luserna stone, laminated, gneiss is extracted in countless quarries located in its surroundings.

It is believed that the exploitation of quarries dates back to the medieval period, but there are only written documentation from the mid-seventeenth century.

The most representative location where you extract the Luserna stone are located:

Valle Infernotto-Comune di Bagnolo Piemonte (CN)-at Montoso;

Val Luserna-Luserna San Giovanni Municipality (TO)-at Seccarezze;

Val Luserna-municipality of Rorà (TO)-cave of the area of Bonet del Prete.

As the pietra di Lucerna, trade name, it means one of the varieties of gneiss that emerges between the val Pellice and valle Po covering an area of about 50 km.

The laminar gneisses that commercially is named Pietra di Lucerna, is a metamorphic rock composed primarily of quartz, feldspar, mica and other minerals.

There are many applications in the construction field thanks to highly characteristic that is easy to form slabs.

Part of the crude product, named cliff, is primarily used to arm the embankments of the rivers so as to avoid flooding, and reduce environmental impact unlike other alternative materials (concrete).

Is widely used in the construction of new roads.

The finished product is used especially for urban pavement, curbs from the sidewalk and slabs, and in private buildings with stairs, balconies, paving slabs, lintels, sills, roofs, etc.

You can see that in all stages from cultivation up to Luserna stone does not throw away anything, '' TOUT VENANT ''

Formerly the quarrymen, in their laborious work, used hammers, chisels, wedges and ammonium nitrate explosives, today replaced by advanced technologies, hydraulic drifters, earthmoving, detonating cords, black powder, diamond wire.

MINING OR GROWING PHASE OF THE QUARRY

 

UNVEILING

 

The unveiling is the first stage of cultivation of the quarry, which will allow the subsequent extraction stages.

Using earth-moving machines (excavators) and the use of explosives, where necessary, removed superficial coverage of the site (capellaccio).

 

THE BANK CUT

 

 

Lamellar gneiss blocks are taken from quarrying banks using primarily the hydraulic drifters.

Once the rock Bank be extracted (there are real growing projects of the quarry) are accomplished with the hole punch vertically inside the rock, the holes are aligned from one another from 20 cm to 30 cm. Are fixed to the rock drill of barramine that can measure from 80 cm to 8.60 meters long, equipped with a special diamond tip drill the rock and retrieve the ammassandola drilling dust into little piles, the main purpose is to prevent this waste into the air and is reused for the Sprint preparation of mine.

Obtained the holes, aligned and parallel, are placed the detonating cords from 3gr-6gr-9 Gr. nut-12gr per cm depending on the piece of rock that you want to remove from the mountain.

If the detonating cord will split the blockage, using black powder added protected by rock powder extracted from the rock drill and hole flooding with water, will allow the Boulder of detached and stir from the main bank in the Sprint.

The primary block extraction method in these cave (Seccarezze) is using a special machine equipped with a diamond wire cutting the rock with a smooth, clean cut in this way the blocks obtained will not be solicited from the explosive that can trigger a process of fracturing.

The extracted blocks are delivered in firm ready for processing.

 

LUSERNA STONE

 

SAWING

 

Using mechanical means, blocks are placed in line with the diamond disc saw machine.

The diamond disk year different sizes depending on the block that you want to slice, vary from 50 cm in diameter up to 3.5 meters.

Sawing machine can also be multi disc, are also used diamond wire sawing machines to cut bad parts of the block.

Attractive and effective is the multi-blade chassis with which you can slice into a single solution the Luserna stone block, in order to fulfill this task the frame works tirelessly for four or five days without ever interrupting the sawing phase.

 

FLAMING

 

The Luserna Stone plates obtained by sawing are cleaned using a thermal process that heats up the surface, using torches to get natural stone.

 

ALTERNATIVE PROCESSING

 

POLISHING

 

This alternative processing is done with a special polishing machine that makes glossy sheets used for paving slabs subjected to polishing do not undergo the first trial of flaming.

 

BRUSHING

 

This alternative route is run from the same machine that polishes simply changing the brushes.

Brushing makes the rough stone but smooth resulting in a sense of warmth.

THE MINERALS

 

Research, study and mineralogical investigation resulting in systematic sampling of the minerals of this place was only possible thanks to the hard work of excavators that have turned our applause for the outcome of the research.

 

 

Aeschynite in crystals, crystals in albite , anatase crystals, arsenopyrite crystals, Crystal bismutite , brookite crystals, calcite , cerussite crystals in chalcopyrite crystals, crystals, chlorite in cosalite crystals, crystals, epidote crystals, fluorite crystals, galena crystals, Hematite crystals, Crystal hellandite , heulandite crystals, ilmenite in laumontite crystals, crystals, magnetite , crystals marcasite crystals, molybdenite, Opal, pyrite crystals, quartz crystals, rutile crystals, stilbite crystals, Crystal synchysite , titanite crystals, wulfenite crystals.

Permission to research in the cave is subject to the consent of the licensee.

THANKS

 

My heartfelt thanks to Istituto Geografico Militare in Florence that has made available the cartography of the area treated.

Thank you to the dealers of the cave Rocks High in the person of Angelino Mauro and employees who gave a chance to the author of this report.

We thank Bruno Marello, Beppe Finello, Graziano Delcore and Andrea Rosso.

 

Copyright 2019
Minerali Piemonte
Management by
MSGWEB
Photos and descriptions edited by
Patrizia and Massimo Deidda
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