We are currently restoring a river after taking out a lowhead dam. There is 4 feet and more of silt deposited above where the dam is, which has to be reused as fill material for greenspace on the river banks. When the material is removed from the river, it is around 50% water, but after it sits in a stockpile for a few days, the water drains out and it then just good 'ole river mud, about the consistency of pudding.We are trying to come up with a method of using quicklime and flyash to modify the mud, so we can use it as fill. Our problem is, machinery will not travel over this mud. When you use lime and flyash in dirt, you raise the pH level quite a bit. The engineers are afraid of "spilling" the material in the water and causing an enviromental disaster of some sort. Does anyone know of a method of applying quicklime and mixing it in mud of this consistency that is cost effective without hauling it to higher ground and then hauling it back after it is treated. A better solution would be to have a way to lower the pH level without using a sulphate based product like fertilizer. Sulphur reverses the effect of quicklime in 6 months to a year after it is applied. Quite a problem, but I'm sure someone out there has run into this before. Thanks: DIRTFAN
A quick and dirty method would be to mix the quicklime with an excavator using the 2500 lb tote bags and mixing it with the bucket. Put some silt fence on the downstream sides of your mixing area.
I have had a similar situation near a river declared Waters Of The State, here is what we did: lay out the mud in a shallow enough layer that you can work it with equipment (dozer/excavator) lay it out the way a 3 lane road is with a lift of mud on each side lane of the road and the turn lane in the center on original travelable ground. We then used tankers to import the lime and pump it into a spreader truck which would spread a layer of lime in the "turn" lane between the two lifts of mud. Mix and repeat. The use of tankers and a proper spreader truck keeps the lime well under control. Once you get the soil to the desired consistency you can place it, then till in fertilizer to the top layer to create the desired ph in your seed bed. I'm not certain as to the risk of ground water carrying the lime in the deeper soil into the river as our experience involved placing the material as normal fill.
What about half rounds that they use for containing drill cuttings until they can be made suitable for transport in a dump truck. They are sealed so spillage isnt an issue and you can stirr them with a decent hoe. Around here they mix some lime and some low grade wood pellets with the cuttings to make them transportable. Oh a 1/2 round is a round belly 40 cu yd dumpster basically.