Project ¡VAMOS! Let’s Go Real!

¡VAMOS! equipment on trial at Lee Moor, Devon, UK.

One month ago, we concluded the ¡VAMOS! project with a presentation at the European Commission headquarters in Brussels1. A relieving event after an amazing project. It all started long, long ago, when several people from the early partners came together and their creative minds forged a brilliant concept: let’s apply the experience from the off-shore mining machines to submerged inland mines, to retrieve minerals, which currently are not profitable to exploit2.

There were three major questions in the project:

  1. What will the production rates be in relation to the minerals that can be expected?
  2. How do we find out, where the valuable mineral is in a submerged environment?
  3. Is the alternative system indeed as easy to handle and environmentally safe as envisioned?

All these issues have been addressed in various work packages. As this was not a desk study or a lab experiment, we needed real hardware to test in field trials. A mining vehicle, a hybrid ROV and a barge to launch the others. The engineering and building was interesting in itself, but the real test was in the two field trials. All the equipment and the people had to perform there. And after all these years since I helped writing the project proposal, it worked! I love it when a plan comes together!

All three research questions can be answered positive. We know how to handle such a system and the hardware required. It will definitely look different than the test vehicle. Here we optimized the engineering for the test, not for production or operation. But we definitely know how to configure the components in a viable operating system. The cutting system was tested to the limits, and production rates estimated. This machine was too light as a production model, but the cutting technology will be able to handle the hardest mineral, as long as weight and power can be applied. As there is no direct vision under water, we developed a data fusion system, where measurements from video, laser, sonar and GPS where the environment was presented in meticulous detail and the vehicle completely modelled in geometry, position and movement. At the pit floor, we were literally driving in virtual reality. The machine created some turbidity, deteriorating vision, but it happened to be less persistent than initially thought. The influence from precipitation runoff into the pit caused more turbidity. All together, we also prepared several business cases for this system against a conventional solution and there are certainly opportunities for a ¡VAMOS! solution.

Results from ¡VAMOS! (a) Cutting tests (b) Virtual vision (c) Equipment handling (d) Viability example (Credit: ¡VAMOS!).

The EU was also very interested whether clients were lining up for the real product. However, investments in the mining industry are slow, long term projects. Our main objective was to find out the operational parameters and present this as a viable alternative to conventional system. And that is what we’ve achieved. And the technology has matured enough, that when there is an opportunity for such a requirement, we are confident, that the tested components can be scaled to production size and readily applied. As a research project, we are finished. At each partner, we will still be working on the test results and improving our technology further. For the interested customer: we are ready to offer a production model. ¡VAMOS!: let’s go for real!

A happy team after concluding the ¡VAMOS! project.

References

  1. The outcomes and the future of the ¡VAMOS! project, ¡VAMOS!
  2. Developments in Mining Equipment and Pumps for Subsea and Inland Submerged Deposits, WODCON 2013

See also

Discussion at LinkedIn post

Graduation Gijs Ter Meulen: Drag Analysis And Model For Forces And Production

Gijs proudly presenting his MSc. certificate.

We have another bright new MSc. engineer in dredging technology1: Gijs ter Meulen. Tuesday, he presented and defended his thesis on the forces and production of a trailing suction head. For this thesis project he was working at our research and development department at Damen Dredging Equipment2.

Trailing suction hopper dredges have become the tool of the trade for modern dredging contractors. They are versatile, flexible and able to transport sand over great distances. They load their cargo in their holds, by sucking up the sediment from the sea bottom with a big trailing suction head. This head looks like an out of size vacuum cleaner head.

Typical drag head on a railing suction hopper dredge.

Usually, it is very difficult to comprehend what is going on in and around the drag head. There is some laboratory research done, but not all results are freely available. Other knowledge is solely based on the experience of well-seasoned dredge masters. I do have respect for the experience of dredge masters, but their stories are hardly usable for an academic model description. So, Gijs took on the challenge to piece together a model, that satisfies our curiosity and fits with the experiences.

Concise development of the drag head model by Gijs ter Meulen.

For this project, he identified several steps, which we briefly touch upon here:

  1. The processes and forces around the drag head3 were all investigated on their cause and effect.
  2. A model was set up, where each process and their interaction with the others were identified.
  3. One main process in the drag head is the jetting production. A powerful jet of water is injected into the soil and this erodes part of the sediment under the drag head4.
  4. Another main process is the cutting production5. What is not eroded away by the jets, is removed by the teeth at the back of the visor.
  5. As the contribution of the processes to the forces and the production is known, the total performance can be calculated.

Along the way, this gave us very useful insight in the capabilities of the drag head and the trailing system, all the way to the requirements for the propulsion. Now, we will be able to continue to improve our drag heads even further. Any other students who would like to participate in that project are welcome to contact us5.

Gijs takes a new step in his career path. He is going to work for a well esteemed customer of us, so we will see him around in the dredging industry. Thanks Gijs, bon voyage!

Gijs, good luck with your future career in dredging.

References

  1. MSc Offshore & Dredging Engineering, TU Delft
  2. Innovation, Damen Dredging Equipment
  3. Designing Dredging Equipment [OE4671], Vlasblom
  4. Sand erosion with a traversing circular jet, Robert Weegenaar
  5. The Cutting of Sand, Dredging Engineering
  6. Internships, Damen Dredging Equipment

See also

Sunken Treasures From ¡VAMOS! At Silvermines

Overview of the ¡VAMOS! test operation in the Magcobar Pit, Silvermines, Ireland

Last week, I was at a test site for the ¡VAMOS! project. It was in the abandoned Magcobar Pit1. Well, only in ancient times, people have been digging for silver at this location. In 1963 the site was opened for a large scale operation to mine Baryte2. A mineral used in the oil industry. After the veins ran out in the open cast mine, they continued underground, extending the tunnels almost to the next mine in an adjacent area. Then they had to stop operation altogether and the pit got filled with water from a small river that now enters in an attractive waterfall. So far the historic perspective of this site. Currently the forgotten mine is bustling with activity. So many people and equipment was brought in from all corners from Europe, it looked like a circus has come to town.

The ¡VAMOS! road show on its way to Silvermines, Ireland

When I came there, the team had already set up camp and assembled the Launch and Recovery Vessel. The Mining Vehicle was ready to be deployed and we could commission and test the special drive we had provided for the project3. Another item we had to commission was the dewatering facility. Well, it is a fancy name for a dump area. Basically, it is a reclamation area, where we can collect the material that has been cut by the mining vehicle and was pumped through the discharge line to the shore. We had one pond for collecting the cuttings and one pond for containing the fines. Eventually all effluent water was skimmed trough an overflow box.

Overview of the dewatering facility

As there might still be some very fine material contained in the overflow water, we wanted to dispose the water at a lower level than where we were going to do the cutting tests with the mining vehicle. This would ensure clear visibility and an undisturbed background turbidity for the effects measurements. A submerged pipe line for dredging is a well-known component in the dredging industry. If e.g. a discharge line of a cutter suction dredge has to cross a busy fairway, the discharge line is submerged under water, so the traffic can pass without interruption.

Example layout of a submerged dredge line

There are several issues to pay attention to. Selecting the right diameter is the first to consider. You definitely don’t want to block the submerged dredge line. In order to reduce the critical velocity and increase the mixture velocity, the diameter of the submerged pipe is usually chosen a bit smaller than the rest of the pipe. Furthermore, you don’t want any air get trapped in the submerged line. Air inside the line will make the pipes float again, usually at the most inconvenient moment and probably damage the line. Positioning the submerged line can be done by actually having the air in the line slowly escape. The line will lose buoyancy and settle on the bottom. Injecting compressed air will float the line again.

Deployment of a submerged dredge line

The mining we are doing at the Magcobar Pit is solely for scientific purposes. The material we gather and sample will not be used. But, we hope our technology will revive some disused mines again to their former glory. At least get some people back at work. There are a lot of little villages that fully depended on the activity of the mine. The little town of Silvermines is still remembering those good old times with a little monument to commemorate a glorious past4.

Memorial for the mining industry in the town of Silvermines

References

  1. ¡VAMOS! preparing for second field tests in Ireland, ¡VAMOS!
  2. Baryte, Wikipedia
  3. Dual Stage Dredge Pump and Double Action Pump Drive for ¡VAMOS!, Discover Dredging
  4. Silvermines, Wikipedia

See also