18 October 2012
METAX A Potion of Knowledge
18 October 2012
The MOSE (MOdulo Sperimentale Elettromeccanico: Experimental Electromechanical Module) is a project intended to protect the city of Venice in Italy, from floods. This project has been carried out by the Consorzio Venezia Nuova on behalf of the Ministero delle Infrastrutture e dei Trasporti (Italian Ministry of Infrastructures and Transport) and of the Magistrato alle Acque di Venezia (Venice Water Authority). It is supported by a “sample” of batching and jet grouting injection plants. Let’s see the details of the project.

On the MOSE’s building site of Lido Nord Treporti (one of the planned sites, together with the ones of Chioggia and Malamocco), they are now carrying out the progressive positioning of the threshold caissons in the trench system, previously dug in the area of Bocca di Lido. The caissons consists in concrete blocks that will support the protection gates of MOSE; the ground consolidation of this installation requires a complex intervention that involves the most advanced technological skills of the company Mantovani Spa, assisted by the project creativity of Metax, engineering division of the company Cima Spa, that offers diversified solutions to the specialized high-profile building industry since 1987.

We are in the company of Mr. Pasquale Triggiani, qualified technician and Managing Director of Metax division, on the north-east side of Bocca di Lido, in front of the waterway that leads to Treporti. Within this area there are two facilities, which are dedicated to the production of cement mixtures used for consolidation injections into the seabed. In particular, our visit to the building site regards the new JM40PV plant, which runs fully automatically, according to the sum of the weight method.
The role of these facilities is essential, and the construction of the structures was made in a specific way, paying great attention to details, on behalf of the Metax research and development department. “The first system of this kind has been designed with the aim of producing cement mixtures also using sea water, reducing high costs due to the traditional use of fresh water”, explains the industrial expert Pasquale Triggiani. “It is a technology developed in co-operation with the company Mantovani Spa and implemented after a series of successful tests, already in the first start-up years of the MOSE building site, at the end of 2004. The first installed batching plant was the JM30, which is still running. Then, we made a revised and corrected version, enhancing the whole system with the implementation of an inverter and the use of a series of innovative technologies that enable the management of a highly complex mixture that has a very high density and a very low viscosity”.
The operation of the facilities delivered by Metax division is shown directly by the person entrusted with the production and injection of cement grout at Lido Nord Treporti, Mr. Silvio Dell’Andrea, mining technician and co-ordinator within the special foundations division at Mantovani Spa: “The new JM40PV represents the crucial plant dedicated to consolidation injections during the laying of the caissons in the seabed. In recent months, with the help of several tests, we have studied the ideal mixture for injections, that have confirmed the excellent quality of viscosity and of the specific weight combined with high flow capacity”.
The main parts of the JM40PV are: storage silos, hopper for additives and special powders, water tank embedded in the plant, electronic control unit with weighting system (for the control up to 10 components for 20 different type of mixture that are stored in the memory). “However, with this plant we control up to six or seven components”, points out Triggiani. “All operations can be recorded and controlled by means of a data logger, also conceived by Metax division, which delivers functional reports in real time. Each hour, during the standard operation, the system carries out a series of tests on the viscosity and the specific weight of the mixture. Even for weightings of 500 or 1,000 kg, we were able to obtain a difference of 1 or 2 kg only, bringing the qualitative results reached in the laboratory at an industrial level”.
Still speaking about the technological improvements of the JM40PV compared to the primitive model JM30, the new machinery is equipped with a centrifugal pump with vertical axis, both in the mixer and in the storage tank with agitator: this innovation allows the obtainment of an excellent mixing quality by significally reducing maintenance costs at the same time.


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