Exhibition ‘Sand On The Move’ At The National Dredging Museum

Flyer for the exhibition ‘Sand on the move’ (Credit: National Dredging Museum).

As we’ve seen in my last post, sand is one of the commodities most in demand1. Here in the Netherlands, there is a whole industry built on the extraction and distribution of sand. One of the most used extraction methods is dredging, something we’re well acquainted with. One of the most used distribution methods is barge transport. And the National Dredging Museum has opened an exhibition on these complementary trades: ‘Sand on the Move’2.
Last Thursday was the opening of this new exhibition of the museum. For the occasion, there were two speakers invited. Kees van der Veeken, director Consortium Grensmaas showed us the current practice of sand mining. Tjeerd Roozendaal, head engineer – program director projects and maintenance of Rijkswaterstaat had the honour to open the exhibition. Afterwards, there was a dinner buffet available for the guests. An excellent opportunity to learn, hear opinions and build on your (dredging) network.

Panoramic view of the ‘Sand on the move’ exhibition.

Our modern infrastructure was only made possible by the application use of sand as foundation of roads and fill material in concrete and tarmac. At the exhibition, there are displays of four big projects about sand mining: ‘Betuweroute’3, ‘Kraaijnbergse Plassen’4, ‘IJsseloog’5 and ‘Grensmaas’6. Each highlighting a certain aspect of sand mining in the Netherlands.
Another part of the exhibition revolves around the distribution of sand. And this posed a chicken and egg problem: in order to build roads, you need roads to transport the sand. So, in the early days, before there were roads, sand was being delivered over water by barge. There was a short period, where numerous small enterprises, mostly family owned, filled the gap of transporting sand by barge, taking the place of delivery trucks. Also my family had a motor vessel for sand transportation, ‘Excelsior’. And my grandfather told me many times of his adventures on board and his relative happy times. As this was hard work for sure.

Motor sand barge ‘Excelsior’ (Credit: Co Winkelman).

Along with old photographs of those sand barges, there are also many models and a video exhibit. Each conveying respect to these men, women and sometimes children, that have been toiling to build the roads and railways that we are now taking for granted in our luxurious times.
Unfortunately, these businesses worked to their own demise. As roads and railways improved, there was less need to transport the sand by barge, but directly hauled to the location where it was needed by road. So, somewhere this typical business dried up. Nowadays, sand is still transported by barges, but they are usually owned by large companies, that own the whole product line from extraction, distribution to application.
There is also a small sand laboratory to experience yourself, how many different aspects of sand are involved in selecting the right sand for the right application. At a small scale and easy to understand steps, this represents how we are evaluating sand in our own laboratory. Next to this laboratory, there are many more kid friendly exhibits in the rest of the museum. I can highly recommend you to plan a visit to the national dredging museum these weekends or during the Christmas holiday.

Mini sand laboratory (Credit: National Dredging museum).

References

  1. The World in a Grain, Amazon
  2. Sand on the Move, National Dredging Museum
  3. Betuweroute, Wikipedia
  4. Kraaijenbergse Plassen, Wikipedia (NL)
  5. IJsseloog, Wikipedia
  6. Grensmaas, Wikipedia (NL)

See also

Don’t rock the boat, don’t tip the boat over

DOP Dredge ‘Roanoke’, Long Island, USA

We were quietly enjoying our dinner on a relaxed evening in our vacation. Suddenly, we were rudely disturbed by rumble and clatter from across the valley. For our eyes developed a rock slide. Just as sudden as it started it was already over. Perplexed, we were too slow to capture the event and put it on social media. Afterwards, I took some pictures of the rubble. As you can see, it was not even a proper rock slide, more the collapse of a retaining wall.

Retaining wall collapse, Sóller, Mallorca, Spain, June 21, 2018

Come to think about it, it was not the first collapse I witnessed. Back in 2006, I was visiting our DOP dredge at Roanoke on Long Island, NY in the USA. I had to do some measurements and general inspection. I was below decks connecting the data recorder to the drive system and had to check something with the dredge master. Just when I climbed on deck, he yelled at me to hold on. Immediately a torrent of water and sand was flung horizontally over the dredge. Some stones cracked a window in the control cabin. Within seconds a tsunami lifted the dredge for about a meter and we kept rocking until the reflecting waves in the pit eventually subsided.

DOP Dredge Roanoke with pit bank in the foreground, before it collapsed. Older bank collapses in the background.

That was one big bank collapse to me. A bank collapse is a known, although undesirable phenomenon in dredging1. It is a result of dredging methods, relying on the development of an active bank to produce a heavy slurry, that is sucked up. However, the sediment does not consist of a uniform block of sand. Usually, the sediment is deposited in different layers, each with their own geo technical properties. These result in varying propagation velocities of the active banks. When a ‘faster’ sand is under a ‘slower’ sand, the upper layer is not supported anymore and collapses. As the bank slumps down, it displaces an enormous volume of water and this often causes a tidal wave of its own. At Roanoke, the effects were aggravated by the fact, that the upper bank ran all the way to above water level.

Progression of an active bank and bank collapse

As this bank collapse can be expected when dredging with active banks and different sand layers, dredging companies are very keen on predicting these nasty consequences. Not only for the safe working condition of the crew, but also to prevent material damage and eventually for a stable and reliable delivered profile. Exactly this is what is being investigated by dr. Askarinejad in the Laboratory of Geo-Engineering at the Technical University Delft2. He has a beautiful rig, where exactly those conditions can be simulated and measured. With a neat trick he tips the whole test facility to form an instable bank. This makes the bank collapse on demand3.

Static liquefaction tank TU Delft (Credit: dr. A. Askarinejad)

Basically, this is exactly what we can demonstrate with the ‘breaching exhibit ‘ in our dredging experience4. Of course you are welcome to come over. For those who are not in the circumstance to visit us, you can also visit the National Dredging Museum as they now have a breaching exhibit of their own5.

Handover of our old breaching exhibit to the National Dredging Museum

References

  1. Breaching Process OE 4626, van Rhee, TU Delft
  2. Amin Askarinejad, TU Delft
  3. Statische liquefactietank , Delft Integraal
  4. Loose sand, how hard can it be?
  5. Baggermuseum krijgt model van Damen Dredging, Binnenvaartkrant

See also

Book Review: Moddergeuzen

Front cover Moddergeuzen by C. Baardman (Credit: JN Voorhoeve, Den Haag)

Summer is in full progress. People are already taking holidays. So, it is time for another book recommendation to take with you and pass your leisure time. Another favourite book from my dredging library is ‘Moddergeuzen’, or ‘Mud Beggars’, by C. Baardman1. However, the English translation doesn’t convey the right feeling about it. In Dutch the ‘Geuzen’ were patriotic nobleman, who fought against the Spanish oppression in the 80 year war2. Beggars sounds so derogatory.

In contrast to ‘Mannen van Sliedrecht’, from my previous review3, ‘Moddergeuzen’ is more describing the personal life of the crew on board the dredges, instead of the big historical picture. Baardman is able to bring all the crew members to life. At least to me. Either by reminding me of stories I heard from my family, or even by similar events I experienced personally. Still, there are some main characters. Most notably Leen Hoornaar and his son Jan. There are also other family ties between the crew members, as was and still is often the case on the Dutch dredges. Somehow, all those stories by and discussions with dad at the kitchen table do convey more knowledge insight and experience, than education at school does. (You need school! What your parents can tell you is your bonus to stand out from the crowd.)

That is also one of the topics Baardman addresses in his book. The old trade handed down from father to son, versus the new developments in culture, where education and knowledge gains momentum in the dredging industry. Another topic is the continuous inequality between the crew members on the one hand and the people from the office on the other hand. Regularly, socialistic thoughts are proclaimed by the crew members, but Baardman voices his idea about social improvement through the characters of Leen and Jan Hoornaar. They are the first glimmers of a work council in the industry. Another social phenomenon is the ever present religious group, that tends to be very conservative. Still, Baardman would rather identify himself as a religious writer. However, his concern to get the message across, but be careful not to look over zealous often made his books read like a regional novel4.

Well, regional is hardly applicable. Just as the dredging industry expanded all over the world, the stories in the book take place in all the now familiar dredging markets: China, Germany, Belgium, France, Rumania. Particularly the storyline in Hamburg was very interesting, as this is also the same time and region where my great grandfather has been working for some time (another story for later). The descriptions about how they must have travelled to and from the project where very illustrative.
Also the pranks they pulled on each other, or more precise on the youngest person on board where very familiar. I’ve heard the story of the coxswain being ordered to fry the cucumber, before. I don’t know if pranks are banned today. At least I don’t hear them so much anymore.

Paper model I received after building my first dredge

Times have changed. So, were the changes described at the story time in the book. Shure, there were a lot steam driven bucket ladder dredge in the adventures. And they do bring most of the exciting adventures. However, modern equipment was on the rise. Plain suction dredges and the first hopper dredges also feature in the book. Remember, hopper dredges at that time were still stationary. Free sailing trailing suction hoppers came much later. The dredge on the cover is a nice example of early twentieth century dredge design. As it happens, the National Dredging Museum in Sliedrecht has model, that looks very similar to the one depicted.

Suction hopper dredge ‘Nautilus II’ for Prins Aannemingsmaatschappij build by J&K Smit

References

  1. Moddergeuzen, Amazon
  2. Geuzen, Wikipedia
  3. Book Review: Mannen Van Sliedrecht, Discover Dredging
  4. C. Baardman: De schrijver en zijn werk, Historische Vereniging Hardinxveld-Giessendam

See also