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LAFARGE counting on innovation with PRECIA MOLEN, to optimize the processing of aggregates.

Real showcase of the expertise from the Lafarge group, the Signes quarry (83) distinguishes itself from the other sites of the group throughout the world, by the innovate implementation strategy to maximize the treatment of aggregates. Its originality lies, among others, in the use of automated solutions for loading trucks, approved for commercial transactions. The latter allows you to take charge of significant site traffic while reducing the loading time. Selected under the terms of a call for tenders launched in 2011, the Precia Molen solutions, specialist in industrial and commercial weighing, have been able to respond to the needs expressed by a rigorous product specification, which included interfacing with the “Quartz” business application, property of the Lafarge Group.

A precursor site, unique within the Lafarge group

With a total area of 73 hectares, of which 33 are exclusively dedicated to extraction, this limestone deposit is intended to produce gravel and sand for BPE concrete or for road products.

Overall view of the loading stationThe traditional loading method is to multiply the number of weighbridges at the output and the number of stakeholders (greeting agents, scale agents…), to perform the loading. It nevertheless has some drawbacks since it subjects the teams to very high cadences during the entire site operating schedule and generates waiting queues that lead to a slowdown of the truck rotations.


A continuous weighing automatic loading station, via a legal metrology conveyor-type scale.

Type BT mechanical infrastructureThe driver presented an RFID badge at the loading terminal which ensures the consistency check between the loading point and the product to load, calculates the net weight to load as a function of the known tare and AGWR.
When the driver is directed to the target loading hopper, it rebadges, which triggers the filling cycle, stops it when the target weight is reached and triggers the printing of a weight ticket.

The driver then gets his delivery slip in an offset position, equipped with a network printer. The driver may leave the site without having to go over the output weighbridge.

The BT conveyor-type weighing machine was revealed to be an original solution for bulk management. It can be used in internal weighing or in commercial transaction Class 0.5, +/-0.25% accuracy or Class 1, +/- 0.5% accuracy, instead of the output weighbridges. It is declined on a 400 mm belt with a 1.2 m centre to centre distance up to an 1800 mm belt a 5 m centre to centre distance and covers a flow range of a few t/h up to 1,200 t/h.

For drivers who do not wish to use the automatic mode, the load can be carried out to the loader and its weighing ensured using input/output weighbridges. At the outlet, the scale agents help drivers to print their weight ticket (WT).

The drivers acclaim the automatic loading

BasculeThanks to the automatic loading station, the cycle is carried out in only 10 minutes versus more than 40 minutes with a human intervention. Since its effective commissioning in October 2012, nearly 90% of drivers choose this mode of loading which allows them, by limiting and rationalizing their presence on the site, to save time and improve their productivity.

Another important strength in terms of quality of service, the certified weighing also delivers the expected quantity, avoiding the risk of over- or under-loading.


“This major project has required a comprehensive approach and could not have been successful without the strong transverse and technical trade skills within Lafarge and Precia Molen. Being ‘all automatic’ implies an evolution of mentalities as well as the agent profiles so that the latter may grasp all the technical aspects of this type of loading. However, the benefits stack up rapidly and significantly. Thus, we have improved our ability to operate our production site” commented Thierry Marchand, project leader at Lafarge Aggregates South.