this is a link to how we do it 200mtrs high http://www.youtube.com/watch?v=3zNuI-7gROk

http://www.youtube.com/watch?v=KhQkoBi-ZCM

http://www.youtube.com/watch?v=GdRUSsFN8Jk

http://www.youtube.com/watch?v=te-P2DAmCpI

http://www.youtube.com/watch?v=3rjcgMDL4gc

Looks like a lot of extra work to me. Why not just suck the ball back and use a diversion valve and pump back to the mixer.Yes u will have a couple wheel barrows of concrete.

On a 200m vertical I would be much happyer when washing the pipes with water then just sucking a ball.. I think its a good system..

My guess is no room to blow back in the mixer.

have done it both ways.  this is a lot safer than air at this hieght.plus there is very little waste concrete most goes back into the pour.and the whole process only takes about 30 mins and every thing is sqeaky clean 

Very Nice! Thanks for sharing.Clean out is an art. Even on small pumps. I like the large unit your running. Good Job!

thanks b-alto  working in aus. would like to see how they clean out highrise systems around the rest of the world if anybodys up to it?

Ive only seen air blow back never seen it dont that way till i saw Meals video on the water washout of a high rise they put a nice video together on that.

lol B.C.P repersent lol good on ya daz and good to see nat got to stick his head in the video lol