Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to the newest version of your browser.

Your browser appears to have cookies disabled. For the best experience of Construction News, please enable cookies in your browser.

Welcome to the Construction News site. As we have relaunched, you will have to sign in once now and agree for us to use cookies, so you won't need to log in each time you visit our site.
Learn more

Exploring new channels

AGGREGATES

Marine dredging in the English Channel has become the focus for firms such as RMC, which insist that besides taking the strain off a stretched aggregates market, the process is ecofriendly. Alasdair Reisner reports

CLAIMED to be the busiest shipping lane in the world, the English Channel has for centuries seen cargoes from around the world pass through the choppy waters between Dover and Calais.And wherever ships go, shipwrecks will surely follow.

Such maritime misfortune and the channel's reasonably shallow waters have attracted a small industry of salvage experts, divers and marine archaeologists, who pick over each newly discovered wreck.

In the coming months another band of entrepreneurs and researchers will be jostling for space among the passenger tankers and bulk carriers.

But the buried treasure they will be looking for does not come in the form of treasures from Armada galleons or trade-route clippers.

Instead they are looking to take advantage of sand and gravel deposits in the so far unexploited east English Channel.

As general manager of one of the firms involved in the move, RMC Marine's John Wilkinson is excited by the prospects offered in the area 'Certainly it seems that the market for marine aggregates is expanding as things go forward, assisted by the difficulty of gaining planning permissions for new quarries in the south-east.'

The move makes even more sense following the recent publication of reports demanding a massive boom in the number of new homes to be built in the south-east, all of which will require a strong supply of aggregates for their construction.

With this in mind, RMC Marine has just completed work stretching one of its dredgers, the Sand Falcon, to allow more efficient dredging and delivery of minerals from the east English Channel, which is further out and deeper than the firm's current operating areas.

But, despite the fact that the marine dredging of aggregates reduces the need for quarrying of inland greenfield sites, this dredging of the mineral riches found beneath the sea is now coming to the attention of environmental groups, which claim it disturbs finely-balanced marine ecosystems.

Mr Wilkinson takes a conciliatory approach to such claims.

'It is quite right that these guys challenge what is going on in the marine environment where we don't know much about the long-term effects, ' he says.

But although little is known about these ecosystems, he adds that, when it comes to understanding the effects of dredging on such habitats, the people with the best knowledge are the dredging companies themselves, which have to collate this information as part of their licensing conditions.

'We are not blundering in there blindly, ' says Mr Wilkinson.He points out that one of the key conditions for anyone dredging coastal waters for aggregates is that they do not scrape away the seabed right back to bare rock or clay.

'One of the fundamental rules is that we must leave a bed of gravel down there, usually about a metre or so, to allow the sea bed to recover, ' says Mr Wilkinson.

That is all well and good - but who is to say that, when miles offshore away from prying eyes, you won't just hoover up everything on the sea bed, whether in your licensed area or not, and scarper back to shore with your booty?

'Every ship has a computer linked to a global positioning system which is automatically switched on when the dredge pipe is lowered. It also measures the quantity of material taken onto the ship using a nuclear density meter.

'All the information from the computer is sent directly to the Crown Estate so they would know straight away if we were in breach of our licensing conditions.'

Mr Wilkinson says the east English Channel has reserves for at least 3050 years according to current understanding of the area.

These materials can be delivered right to the heart of London, where demand is highest, thanks to dedicated wharves on the Thames.

From here it is just a short barge journey to RMC plants at Vauxhall, Battersea and Fulham, allowing the collected material to be distributed around the capital. Such a direct route into the city has environmental benefit as it reduces the number and length of wagon journeys required to deliver the material.

So, with this bounty lying below the surface in the channel, isn't Mr Wilkinson concerned that other firms may catch on and compete for the rights to dredge it?

If he is, he isn't showing it.

'Not everyone has licences and it isn't easy to get them. It can take up to 10 years and there are no newcomers rushing in, ' he says.

'Even if somebody did try to come in they would need £20 million to invest in a ship, so there are limited options for entry into the market.

'Even if you did try to enter the market with a ship that could, say, dredge two million tonnes a year, you would have to market all of that material or you would have an under-utilised ship that just burns cash.'

So it seems that RMC Marine's efforts to gain licences for the English Channel are set to pay dividends and help take some of the strain from the stretched market for UK aggregates.

And in the current climate it is unlikely that Mr Wilkinson's hopes for the business will be dashed on the rocks.