Pond Boss Forums Thread Like Summary - Gold dredge for muck removal?

I posted in another thread discussing muck removal options but thought I would give this a dedicated thread. One suggested DIY solution to remove organic muck from an old pond is to build something akin to a gold dredge with a trash pump and a venturi dredge nozzle. Does anyone have real world experience doing this? Did it work well? Any tips or lessons you learned along the way?

My thought is to build a platform to paddle/pole around the 1.75 acre pond that can be anchored in position. A 3" trash pump would ride on the platform. A pole would be attached to the nozzle (so the user can stand on the platform and suction the bottom). The mucky water would be sent to the shore where some form of dewatering would occur (dewatering bags, silt screens, etc.). Here are some visual examples:

Nozzle
http://i.ebayimg.com/00/s/OTAwWDE2MDA=/z/K54AAOSwPhdVEPzT/$_57.JPG?set_id=880000500F

Overall setup, minus the sluice
https://suertegold.files.wordpress.com/2013/02/dredge-suction-diagrama1.gif

Three homeowners share our pond and there is a guy up the road who is facing the same problem with his pond. A dredge company quoted the guy up the road $7,000 to clean half of his 0.75 acre pond. That is not affordable for any of us.

I'm looking to pitch the idea of building a platform and dredge to the other 3 parties with the idea of splitting the build cost 4 ways. Depending how nice a pump and hose we buy, I'm guessing this would be a $2000-2500 venture divided 4 ways. Then it is just a matter of chipping in time and we are not in a rush. The bigger concern is to not stir up the bottom and turn the pond toxic to the fish. Before I get serious about pricing out equipment and talking to everyone, I want to make sure this method is truly viable.

I would appreciate hearing anyone's experiences and thoughts.

Thanks!

We use a similar approach to dredge sludge from mine drainage treatment settling ponds. The settling basin has to be fairly large. Surface area is the key, and shaped right or baffled to prevent short circuiting. We use polymer blocks to help settle solids sometimes, just depends on how fast they drop out. Dewatering bags work sometimes, sometimes not so well if the solids plug the fabric or blow through. Figure pumping about 10% solids / 90% water to keep from plugging piping / hoses, but maybe get up around 15% if it moves well. Too much solids over too long a distance stalls the pump and makes for a real mess. It takes a good bit of water to move sludge, but if you have the time it can be done. We recirculate some of the pumped water to jet / hose down the solids to the pump intake (we're using large hydraulic powered submersible pumps hung off cranes and diesel shore power units, same idea, but larger scale). Some of the submersible pumps we rent have a nozzle setup using some of the water to continuously blast the sludge around the pump intake - potholing. Hope that helps. Dale