¡VAMOS! mining concept for submerged inland mining on any continent

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

Today, the WEDA Dredging Summit and Expo 2018 starts1. Tomorrow, Olivier Marcus is going to present a paper on the ¡VAMOS! project2, I assisted co-authoring. The message we wanted to convey is the applicability of the ¡VAMOS! system we’ve developed in a European Research and Development consortium3. By now we were well acquainted with the European Situation, but as this was going to be presented in the United States I had to do some research all over, for the American market situation. It turned out that ¡VAMOS! concept could be used their as anywhere else.

Schematic of typical vertical ore body in an opencast or submerged setting (Credit: ¡VAMOS!)

First of all, some explanation what the ¡VAMOS! project is about. We’ve noticed that here in Europe mineral resources are heavily depleted or located at locations that are not accessible due to their economic or environmental value. One solution would be to dig deeper, but in open cast mining, you’ll run into an enormous overburden removal and drainage problems. The other is to tunnel mining, but that is very expensive and dangerous. The ¡VAMOS! concept opens up a new approach: submerged mining.

Diagram of the original ¡VAMOS! concept (Credit:¡VAMOS!)

Instead of pumping the water out, we use it to transport the mineral to the plant. And this is very familiar for us in the dredging industry. So, we’ve found another location where we can discover dredging! Usually dredging involves transporting huge volumes of sediment, but the fraction of the ore, that is really paying for the operation tends to be very small. In mining terms it is the ore grade. Depending on the ore grade, the operation can be economically feasible or not. As this is a very fine line, mining economics have already done a lot of research on this and they call it the ‘Exergy Cost’. In short: an operation for low grade ore may be more expensive when the mineral is expensive. In fact, when one is mining sand, the ore grade is 100% and the price will be low, so the profit has to come from its volume.

Exergy cost (kWh) needed for producing a given mineral from bare rock to market. (Credit: Valero)

This model is basically applicable in both the European and the American market. Although the local business mentality will result in different underlying economic calculations. In Europe we were working with a report on the critical resources that are on the agenda of the European Commission4. It turns out, that now the United States has their own list of critical minerals5, just signed into executive order6. The list differs somewhat, but is certainly recognisable. This is a good indication, that the ¡VAMOS! mining concept can be evaluated equally to the other options for the American market.

Medium-Term (2015–2025) Criticality Matrix (Credit: US DOE)

So, who knows, maybe there is an innovative entrepreneur in Olivier’s audience at the WEDA and the first real production model might be put to work in an American mine. At least, when delivering a product like this, we would not have to worry about the Jones Act.

MV handling on LARV at Lee Moor test site in Devon, UK

References

  1. Dredging Summit and Expo 2018, WEDA
  2. WEDA Dredging Summit & Expo, Damen
  3. ¡VAMOS!
  4. EIP on Raw Materials, European Commission
  5. Interior Seeks Public Comment on Draft List of 35 Minerals Deemed Critical to U.S. National Security and the Economy, US Department of the Interior
  6. A Federal Strategy To Ensure Secure and Reliable Supplies of Critical Minerals, Executive Order 13817 of December 20, 2017

See also

How DOP Pumps Developed and Entered the Digital Age

First application of a DOP pump

Recently, my daughter asked me: ‘Dad, what good is it to know your history?’ And I answered: ‘Dear, if you don’t know your past, you will not understand the world around you.’ And the world around us is changing rapidly. The most recent change in our dredging world is the launch of the DOP web shop1. The ultimate entrance into the digital age of a well proven pump. For those young people that only know how to order online (or others interested in dredging history): long before webshops were around, customers and suppliers had a direct relationship with each other.

In the early ‘90s, when Ballast Nedam received the contract to build the railway tunnel near Schiphol Airport2, they had a real tough challenge. The ground water level near Schiphol is very high. Any hole there, fills up rapidly. Using sump pumps to remove the water from a building pit would be useless. To prevent collapse of the sides, there was already sheet piling in place, supported by braces to carry the side load. The space between the braces was too small for a long reach excavator. And the area under the braces too low to work from pontoons. Moreover, the foundation pilings where already in place and they should not get damaged by the excavation with a crab crane.

Construction site of the railway tunnel at Schiphol Airport

At this point, Ballast Nedam contacted their supplier De Groot Nijkerk for a smart solution. Ballast Nedam wanted a small self-contained dredging machine, that would fit between the braces and remove the sediment hydraulically. In a real Gyro Gearloose fashion, De Groot Nijkerk managed to patch together a contraption to prove the concept: ‘the first DOP pump’ (of some sort). It consisted of a normal dredge pump and a submerged jet pump in the same frame.

Proof of concept for a DOP

The tests were successful and the prototype was turned into a production model. The main difference being that the bearing and the dredge pump were designed with a mechanical seal to remove the gland water installation. This mechanical seal required some development on itself, as standard mechanical seals were too fragile. The newly developed seal was of real dredging proof quality. The product was successfully used and word spread around the Dutch contractors about this nifty little dredging machine. As a result, the new DOP was introduced in 1991 and started a career of its own.

Introduction of the first standard DOP on the market

As customers were very original in creating their own solutions for their specific problems, this single product slowly evolved in a whole line of products and options3. For as long as I remember, there was this picture in the product leaflets, that the customer could use to configure their own tool. Hence the slogan: ‘Your job, our tools.’

Typical selection diagram of DOP options

Over time, the range has been reengineered and thoroughly standardised. Due to this standardisation, the sales could also be standardised. Thus, the natural consequence: the webshop. Here you can experience online convenience with personal service.

Real DOP’s on display. Buy them at https://dopshop.damen.com/

References

  1. Damen DOP shop
  2. Schiphol Airport expansion, Wikipedia (Dutch)
  3. The DOP® submersible dredge pump and the possibilities for the contractor, DPC December 1998

See also

 

 

A Sample of Soil Samples

Soil sample exhibit at the Damen Dredging Experience

‘Welcome Sir, very nice you would like to buy our dredge. What do you want to dredge with it?’
‘Sand.’
‘Ah Sir, very well. Our dredges are very capable of dredging sand. What kind of sand are you going to dredge?’
‘Grey sand!…’

Sounds familiar? Well to me it does. Sometimes, even our most esteemed customers lack a basic knowledge of their primary process. Often, I’ve been called into a meeting with the customer, to explain about sand and its physical properties. Nowadays, we can show them an exhibit in the Damen Dredging Experience1 to discuss their particular case. Eventually, we can tease out the information we need, to inform the customer the estimated production of their dredge. Educated customers do know about their operation and can make the estimation themselves.

There are several parameters that influence the performance of the dredge. Particle sizes, grain forms, densities, mineral types, cohesion and many more. And we are very happy when the customer already has his own soil report of his particular operation. This would comprise bore logs, particle size distribution and cone penetration tests. If this is not possible, a sample of the concerned soil will do. We do have our own small soil mechanics lab, in which we can measure the required properties.

Elementary soil mechanics laboratory at our company

The most useful property is the particle size distribution or PSD. This can be done in a sieve tower. (red circle) The soil sample is placed in the top sieve and the sieves are vibrated to separate the various fractions. The contents of the sieves are weighed and plotted in a logarithmic graph. This resulting PSD can then be used in production estimations.

Procedure to establish a particle size distribution

For a good measurement, we need a sample the size of a 1.5L coke bottle. About two thirds of soil and one third of water. We need the water to capture the fines in the sample. Do not drain it! And the bottle is a good container for transport and widely available. Stash it in your check-in luggage. Otherwise, you will run into trouble with the airport security about carrying liquids in your hand luggage.

Examples of sample containers encountered for estimation

All these variations in soil properties have a major influence on the performance of the dredge. So, this is why we would like to know exactly what the customer is going to do with our dredge. Otherwise, we might end up in an analogous situation when somebody wants to buy a truck. You can explain all about the installed power and the cargo capacity and then you get this question:
‘Sir, can you tell me how much paper I can transport with this truck?’
‘Ah well, we are not in the transport business ourselves, but as you are a good customer, we can make an estimate for your convenience. What kind of paper? Kite paper? Cardstock? In blocks, boxes or roles?’
‘Oh, I don’t know. Just paper’.

Model dump truck from a customer2, typically used at dredging projects

References

  1. Kommer Damen opening the ‘Damen Dredging Experience’, DredgingToday
  2. 2. 35 ton dumper, Martens en Van Oord

See also