Underwater Extraction of Sand and Gravel

摘要

Thirty years ago approval for planning permission for new sand and gravel extraction sites was obtained without too much cost or effort. Easily accessible deposits, usually those above the water level, or high-quality deposits were extracted first. Planning permission for a new greenfield site is now much more difficult to obtain and, if granted, imposes stiff environmental restrictions and requires improvements to the locality. To make a site cost-effective companies have to ensure that the full potential of the site's deposit is extracted or return to previously worked deposits using techniques and plant that are efficient for the task. Accordingly, the use of dredging as a method of underwater extraction of sand and gravel has become more commonplace in the UK.