The underground salt mine operated by Südwestdeutsche Salzwerke AG in Heilbronn is huge: a network of roads covering a total length of more than 700 km needs to be maintained on a continuous basis. This Herculean task is taken on by the SF 2600i dinting machine.
The main reason for operating the dinting machine in the salt mine on a non-stop basis is unevenness of the mine floors caused by blasting and cutting during tunnel driving. In addition, previously rehabilitated floor pavements are gradually destroyed again by the heavy-duty vehicles that are needed for salt mining. In both cases, the floor surfaces are covered with a mixture of potholes, bumps, steps and rutting. “The effects are quite severe,” explains Herbert Hesser, head foreman at the mine. “Axles, wheels, chassis and gearboxes of the 150 mobile machines operated in the mine are severely affected by the uneven floor surfaces. The costly consequences are downtimes, high repair costs and increased parts requirements.
When driving on floor surfaces levelled by milling, the mobile machines achieve an average speed that nearly equals the maximum permissible speed in the mine of 35 km/h. On uneven roads, on the other hand, they achieve an average speed of only 15 to 20 km/h. This costs the company money every day. A lot of valuable time is lost, for example, simply because our workforce needs longer to get to their workplaces underground, which often requires them to travel up to 10 km. In addition, fuel consumption increases by an impressive 35% on poorly maintained haulage roads. And last but not least, we have a duty to care for the welfare of our employees. For roads allowing smooth and safe travel protect against health risks, such as back disorders. And in the long run, the company in turn benefits from the welfare of its employees.”
All of these cost factors are eliminated by the SF 2600i dinting machine single-handedly. The predecessor model, a 2600 dinting machine, kept things moving underground from as early as 1993. “But even the most robust machine comes to the end of its useful service life one day. There was no question that we would replace it with the new SF 2600i dinting machine from Wirtgen, which has been providing excellent services here since November 2011,” Hesser adds.
The SF 2600i is equipped with a cutting drum which levels off uneven surfaces to produce a perfectly even floor offering convenient riding properties and minimum rolling resistance. The salt mined in the Heilbronn mine has a compressive strength of between 20 and 25 MPa. Operating at a working width of 2.5 m and a cutting depth of 0.1 m, the SF 2600i achieves advance rates of up to 800 m per 8-hour shift. “This enables us to keep our road network in good shape all the time,” commends the head foreman. After cutting, the material deposited behind the machine is levelled by graders, watered and compacted.
Hesser points out that “the dinting machine has been fully customized to meet our specific requirements. The close cooperation with Wirtgen – whether in terms of machine design, planning, transport, or after-sales service – was most convincing. And the benefits add up: our investment in the new machine pays off through increased efficiency as well as reduced operating and repair costs,” says the expert, adding that “for us, the dinting machine is an indispensable asset.”
Michaela Adams, Mario Linnemann
Press and Public Relations
Phone: +49 2645 / 131-0
Fax: +49 2645 / 131-499
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State-of-the-art road construction in a salt mine. The SF 2600i is a special-purpose machine for lowering the floor levels and for maintenance of haulage roads in underground salt mines with low headroom.
The core element of the SF 2600i dinting machine is a 2.60 m wide cutting drum operating in counter-rotating mode. The cutting depth is continuously adjustable to up to 20 cm, and the specified working depth and slope are then maintained by the machine’s automatic leveling system.
Poor floor conditions increase machine wear and tear, travel times, fuel consumption and health risks.
The floors offer good riding properties after milling, thus allowing higher average speeds.