The economic case for expansion is set out in the recently published document Adding Capacity at Heathrow Airport—Impact Assessment (January 2009). This assessment includes among other things the air passenger duty revenues from additional non-transfer passengers that are forecast to use the additional capacity.
A copy of the impact assessment is available at:
A thorough assessment of historic mapping, aerial photographs and visual appraisal, found that around 43 per cent. of the proposed site area had been quarried for gravel extraction. This assessment is set out on page 31 of the “Adding Capacity at Heathrow - 2008 Historic Environment Appraisal”, available at:
No formal assessment has been made of the impact of additional capacity on the supply of sand and gravel for London’s construction industry. The impact assessment includes estimates of the costs of construction of a third runway. This is a comprehensive assessment, which includes the cost of sand and gravel, and is available at: