Respected for its green attributes, a new dredging innovation saves mines a lot of money and time
“How much do we have to sacrifice to carry out dredging services in our tailings or sedimentation ponds?”
That is the question mining companies are inevitably confronted with. And, most often, the headache is the huge cost it entails.
Yet dredging does not need to be underestimated; it expands the functionality and lifespan of a mine pond. By removing the sediment, it creates additional capacity. The sediment in many cases can be recycled into good use.
A new innovation ensures that dredging becomes the least of mining companies’ worries, Fred De Pauw, Managing Director of Dredging Services, informs African Mining Brief. It enables a mine to keep a sedimentation pond in working order while dredging goes on which is an important process in tailings treatment.
De Pauw explains that Dredging Services’ solution eliminates the need to drain or decommission any mine tailing or sedimentation pond. With their design, the water loss will be kept to an absolute minimum, as all water is re-used by the semi-closed dredging system they work with.
Above and beyond, the need to build new ponds is eliminated, resulting in both financial savings as well as reductions in the carbon footprint associated with putting up a new dam or pond.
Ideal for gold and coal mines
De Pauw endorses the use of the innovation for both coal and gold mines saying
with most coal mines, thousands of tons of coal fines end up in water reservoirs, once the dredging is begun, the tailings are pumped onto a large stock-pile and the coal can be sold again to power stations and other establishments. This helps to cover the cost of the dredging.
In gold mines, where tailings end up in ponds, not all gold is extracted and by dredging these ponds and with additional recovery systems, fine gold can also be recovered, reclaiming gold again for reselling.
De Pauw says Dredging Services’ current dredger is able to dredge lined ponds, without any damage to the pond liner. Where dredging is done with excavators, etc, the risk is extremely high in casing damage to any type of liner. However, with their system, they can “see” the lining and cutter height, and the cutter suction head is adjusted to safe effective dredging depth.
Dredging Services’ dredger can work in any type of water reservoir, as they don’t use “spuds” to anchor the dredger inside a pond, but use removable shore anchor systems on the pond walls and embankments. No damage to pond linings, pipes, reservoir walls/embankments, etc.
They also remove green vegetation with the same dredger. This dredger is designed for smaller ponds and can work to minus 5 meter. It is fully equipped with a depth sounder, Doppler flow meter and all related navigation systems.
Moreover, the company conducts pre and post dredging underwater surveys, to eliminate any discrepancies in volumes to be removed.
What mines ask for
With the benefit of years of experience De Pauw can almost tell the requirement of a mine from a distance. He singles out experience, practical and hands-on and professionalism as well as an excellent work ethic to boot as the qualities that are invaluable for a services provider to satisfy the needs of mines:.
Additionally, clients expect more than just dredging services. And sharing his perspectives on Dredging Services’ approach, he says that with their vast experience they can supply turnkey project solutions, including complete management of the project, consultations and client satisfaction at the end of any project.
When approached by mines for advice on the best dredging output, the first point De Pauw mentions is effective planning, which involves gathering of all site related information, site inspection with related meetings and discussions, mainly with site engineers and technical personal involved with the dredging project on a site.
Additionally, besides scrupulous execution of work, good handling of dredged materials and, most importantly, green measures, should be prioritised.
De Pauw has experienced increasing orders from mines. But, currently, with unstable conditions at most mines and power stations, he says the current trend is to do smaller work projects, on an urgent and “as needed” basis.
However, he observes that, in current conditions mines could think they are cutting down costs by putting dredging on hold, only for the costs of belated interventions to escalate when the services are needed.
Prevention of excess material in any pond is of cardinal importance, as the cost will increase if the pond is eventually rendered useless. “We have seen this in a few occasions where maintenance held off for too long”, says de Pauw.
Using maintenance dredging early and keeping the pond in a general good state will save the client additional cost in the long run.
A clean pond is more effective than a full or partly filled pond. Water is already scarce and expensive, by keeping good water volume in a pond, is better than a half full water pond.