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December 4, 2025

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Lubrication and anti-corrosion of a tunnel drill

Tunnel-boring machines operate in extremely harsh environments, where bearings and rotating components face heavy loads, contaminated mine water, and significant temperature fluctuations. These conditions make reliable lubrication and corrosion protection essential. This case study shows how targeted product choices improved performance, reduced maintenance costs, and increased overall operational reliability.
Description of the situation

The bearings in the cutterhead of a tunnel-boring machine are subjected to extreme dynamic loads, contaminated mine water, and significant temperature variations. Underground conditions further complicate lubrication maintenance. The grease in use could not withstand the mine water and was washed away, compromising the seal between the bearings and the sealing elements. As a result, the lubricating film broke down, corrosion accelerated, and the damping effect that the grease structure normally provides under shock loading was lost.

Specifications
SegmentMining
Lubrication pointBearings en rotating parts
Used productEurol Grease CS-2/502-S 
Eurol Lube PL BIO
Product codesS005121
S009125
Type of machineTunnel drill machine
Solution

By using Eurol Grease CS-2/502-S, the lubricating film in the cutterhead bearings remains intact even under continuous exposure to mine water and heavy shock loads. Its pronounced water-repellent properties and high EP load capacity keep both the rolling elements and the seals optimally protected against premature wear. In addition, Eurol Lube PL BIO deposit a dry, corrosion-inhibiting film on other rotating components, preventing flash rust and ensuring clean, low-friction operation. Together, these two lubricants have lowered total maintenance costs by roughly 25 % across multiple projects, reduced unplanned downtime by 10 %, and generated overall savings of about € 25.000.

Customer testimonial

“Wear stopped and corrosion disappeared. The 502-S grease does not dry out and is very economical in use. No oil leaking. Great EP properties.”