Almost 100 years ago, German drilling business Johann Keller devised “vibro compaction” — using vibrations in deep holes to compact soil and boost its bearing capacity. The FTSE 250 construction engineering firm bearing the Keller name today has gone through myriad M&A deals — it started as the ground-engineering division of the UK’s GKN in the 1950s, before buying Johann Keller in 1975 and rebranding — but some of its 10,000 staff still deploy vibro compaction.
Keller laid 500 vibro concrete columns for the foundations of London’s Olympic Stadium. It also carried out metro tunnelling in Melbourne and worked on a deep sewerage system in Singapore. To potential investors, though, its success seems to have stayed underground: shares in the are down 10 per cent