Ground engineering specialist Keller revealed a massive 70% drop in half-year pre-tax profit following floods in Australia and geopolitical issues in the Middle East and North Africa. However the group expects results for the full year to remain within the current range of market expectations after two major US jobs got underway.Chief executive Justin Atkinson said, "While we continue to make progress in our developing markets, a recovery in our more mature construction markets is taking longer than expected and over-capacity remains an issue, particularly in the US, maintaining pressure on margins in the near term." Profit before tax slumped to £3.4m for the six months ended 30 June 2011 from £11.3m before. Revenue for the period increased to £545.5m from £496.9m earlier. However the group said despite a further contraction in US markets, its North American operations reported revenue of £207.9m compared to £198.0m in 2010, boosted by its contracting business Hayward Baker. The US business as a whole reported an operating loss of £1.8m compared to a loss of £1m in 2010."Two major US jobs did get underway in the first half, which are expected to be important contributors in the second half," Keller explained.Its order book has increased 14% from the same time last year.The total dividend has been maintained at 7.6p per share.---CJ