 Keller's business is ground engineering and with a turnover of 100 million pounds, we're one of the biggest Our main operating centers are in the UK, West Germany and the United States But we have subsidiaries and branches in a further 10 countries Keller operates in three main areas of geotechnical engineering ground improvement, piling and specialist grouting Keller again who introduced the stone column technique or vibro replacement Which can be applied to a wider variety of soil types With this technique gravel or crushed stone is poured into the space around the vibrator and Compacted to form a stone column Then we took the idea a stage further by inventing the bottom feed system in which stone is fed down through the poker and Simultaneously monitored up in the cab The benefits of these innovations are economy and speed Not only that we have the widest range of vibrators