On-site quarrying, each of which produce some thousands of cubic metres of material annually, is carried out using the most sophisticated of technology, and is increasingly combined with similarly advanced block-working systems. The openings of the quarries are sometimes terraced, or at times they are subvertical walls related to the local geological structure and the economic importance of the deposit.

In most of the Ossola gneiss, marble and granite quarries, quarrying techniques permit that quite uniform blocks can be obtained directly from the deposit which then go on to be sectioned and further formed on the quarry site itself. The entire process of these techniques all together is referred to as "taglio al monte" (cutting on the mountain) to distinguish it from sectioning operations that take place on the site, and the sawing stage which is carried out in the appropriate laboratories.

Explosives may be used as a cutting method, but according to newly refined methodologies (pre-splitting) that have little to do with regular mining techniques; a series of holes of a diameter of 30-40 mm are drilled, having a distance of 5-10 times that of the diameter between them, and which get loaded with weak explosives so as to avoid fragmenting of the desired block and to be able to remove it according to the way the holes lie. In these cases the explosive is of a detonated fuse type or, more exactly, a wick containing 10-15 gr of explosives (pentrite) per metre. This method may be used for any type of rock as long as the removal is planned in the best way in relation to natural irregularities (fracture systems) in the rock, or in relation to layers that can split easily (foliation, schistosity). This is the same for all "cutting on the mountain" methods.

For less abrasive rock, such as those so-called marble, normal "cutting on the mountain" methods are used and carried out using a diamond wire system, that is, a steel cable along which are distributed small "diamond chips" which constitute the real and proper cutting tool. This method is increasingly employed especially for large-scale gneiss and granite quarries, and has the advantage of reducing wastage while awoiding damaging the deposit, such as that which can occur during the use of already low-wastage and highly controlled explosives.

After a bank is removed, it gets successively cut down in gangsaw blocks for commercial use via block-cutters (on tracks that permit a perfect alignment and inclination of drilled holes). Turned upside down on the quarry working site, the blocks are subsequently harnessed and hoisted via heavy duty lifting devices typical to quarries (derricks) consisting of two struts, a column with a turning arm for an arc of 270°, and which can reach over 70 metres. This modern materials movement and transport system can no longer be compared to the traditional "lizzatura" (sliding transport), or to telferage, which are much less productive and safe; consequently these latter systems are no longer used. Logically, an access road is required to the quarry which can take the weight and movement of large vehicles: its construction is to be considered one of the most costly investments to be made when initiating quarrying activity.