Marine Aggregates

Britain has one of the world’s most developed marine aggregate industries, extracting 15 to 20 million tonnes from the seabed annually. Much of this is used for building houses, transport infrastructure, replenishing beaches and improving coastal defences. The Crown Estate owns almost all of the sand and gravel resources lying off of the coast of England, Wales and Northern Ireland and awards and manages commercial agreements for companies to extract it.

The recharge of beach material has been an important market for marine aggregates since the 1960s. There is a continuing need for material to replenish exisiting schemes and provide for new ones. it is most cost effective when the material used for the schemes is sourced from the local marine environment, there are strict specifications for the material that can be used.

The Solent lies in the South Coast marine dredging region. In this region figures from the Crown Estate show that 7.5 million tonnes can be extracted annually from 13 licences. Current estimates suggest there are 25 years of primary marine aggregate production permitted. There are delivery wharves at Portsmouth, Southampton, Langstone and Cowes. Of the material extracted in the region 89.6% is delivered to the South coast.

The British Marine Aggregate Producers Association (BMAPA) is the representative trade body for the British marine aggregate industry and a member of the Solent Forum. Every year since 1998, BMAPA and The Crown Estate have jointly produced an annual report known as the Area Involved, which detailed changes in the area of seabed licensed and dredged at both national and regional scales. In 2018, 19.6 million tonnes of marine aggregates were dredged. The greatest demand is for sand and for 10mm, 20mm and 40mm gravel. Any oversize gravel is usually crushed before being re-screened into the smaller grades. Ready-mixed concrete and concrete products are the main uses of marine aggregates, and many wharves now incorporate ‘added value’ manufacturing facilities.

BMAPA estimates suggest that between 3.2 and 3.8 billion tonnes of construction aggregates will be required by 2030 to support society’s ongoing need for homes, hospitals and schools, alongside the energy, water and transport infrastructure we rely upon. Marine aggregates already make a significant contribution to the ‘steady and adequate’ supply of these essential mineral resources, particularly at a regional scale. Of the 20 million tonnes of marine sand and gravel typically extracted from licensed areas around England and Wales each year, over half (c.11Mt) are landed in London and the South East of England. This is significant, given that one third of all GB construction activity takes place here, representing a value of some £50 billion per annum. Elsewhere, marine supplies also provide an important role supporting regional construction activity in the North East, the South West and the North West.

The distribution of commercially viable marine sand and gravel resources around our coastline is highly limited, constrained by their geological distribution and their geographic position relative to the market’s location. Therefore, continued long-term access to commercially viable sources of marine sand and gravel is fundamental to the ability of the marine aggregate sector to meet future demand, as is the need to safeguard these important mineral resources for potential use in the future.

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