Case study: Case CX470C excavator at work in the Botticino marble quarries
A 50-tonne Case CX470C full-size crawler excavator has joined a fleet of six tracked excavators and three tracked loaders in an Italian quarry that produces Botticino Classico marble, as used in buildings such as La Scala theatre in Milan, Grand Central Station in New York, the Altare della Patria in Rome, Harrods department store in London and the Galeries Lafayette in Paris.
The ancient Romans first quarried the stone in the mountains east of Brescia, and it is near here where the Valverde Cooperative is located. The group of 36 partners operates a concession in a quarry that extends over 35,000 square metres and produces over 30,000 tonnes of marble each year.
Valverde Cooperative purchasing manager Maurizio Fraboni says the group chose the Case CX470C because they carry a lot of loads on steep slopes and needed an excavator that was safe, robust and stable while being able to lift up to 27 tonnes.
"We were also looking for an excavator with optimum visibility," Fraboni says, "since visibility means safety, especially in our mountains."
The Case CX470C’s cab achieves a high level of visibility through the use of narrower crossbars that leave more space for the broad windscreen and four side mirrors, in addition to a camera monitor for rear view vision, and a second standard side camera monitor linked to a large colour monitor installed in the cab. The monitor also provides an on-board diagnostic service that allows the operator to pre-programme the power, and the carrying capacity of the auxiliary hydraulic circuit, to a maximum of 10 settings.
Case says other features affecting the purchase decision were the excavator’s ability to move about easily in the quarry’s tight spaces, as well as being powerful and robust enough to handle heavy-duty tasks. In addition, the Valverde Cooperative is developing a policy for reducing its environmental impact, and the CX470’s 270kW Isuzu AL-6UZ1X engine has low noise and exhaust emissions meeting the Tier IV interim emission standards (Stage III/B).
Fuel consumption is reduced by Case’s ‘intelligent’ hydraulic system that provides five functions for saving energy: The Boom Economy Control reduces engine rpm when lowering the boom and during rotation; the Auto Economy Control reduces engine rpm when the joystick controls are inactive; the Swing Relief Control manages the distribution of hydraulic power at the beginning of rotation operation to ensure a more efficient use of pressure and hydraulic reach; the Spool Stroke Control automatically adjusts the hydraulic pressure during excavation; and the Idle shutdown function switches off the engine after a certain period of inactivity.
Paolo Entrade, of the Maren-CMO dealership which supplied the excavator, says the machine was adapted to the cooperative’s needs.
"The CX470C excavator purchased by Valverde was equipped with track rollers with two ribs for ensuring greater friction when approaching the sharp slopes found in the quarry," Entrade says. "The arm barely measures 2.9m, shorter than the standard arm, to provide a better grip when moving blocks of marble. It is also better adapted to the confined spaces of the working areas."
Explosives are used to open the formation, a portion of rock isolated from the mountain, for cultivation of the quarry. The single blocks are stacked one after the other by using diamond wire and then transported by the excavators to the work areas for the subsequent phase of squaring of the blocks. Finally, the blocks are transferred into the storage areas, where they continue their journey to the processing site on trucks.
The heavy-duty Case CX470C is used in operations such as ground work, handling blocks detached from the mountain by explosives, and keeping the work area tidy.
"Prior to purchasing, Maren-CMO offered to let us try it for a while so we could feel the stability of the unit and its ability to get over any slope effortlessly," Fraboni says. "Our cooperative only purchases new units if our operators give us their vote of confidence for the machines. They need to feel secure about the units that they are asked to operate and the CX470C excavator offers the technology, the robustness and the stability necessary to put our extraction operators totally at ease."
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