I mucked up the angles on Page 10. The tray is set at 20 degrees and the base of the boil box is 180 degrees. I'll post a correction hell 75 degrees is almost straight up and down. The water was provided by a very small creek , we re-circulated. The feed was from a 3 inch slurry pump, 8hp motor. Was split into two 2" lines, one line to each tray. The suction head was where the matrial was classified. We had a seperate pump injecting a water jet through a lance into the hole where the suction head was. This agitated the sand and meant the head didn't get locked in. On full power it wanted to sucked right down. We controlled this by a rope tied to the head and the plank. We lost one head which went to china.. We also had another pump suppling water just above the suction head. It had a valve and we were able to regulate slurry consistency. Plus if we ever did lock the head in. All we had to do was shut down the 8hp slurry pump, turn the other one up and the water flow went through the suction head and loosened things up. Designed that after we lost the first head. In places we had that hole twelve feet deep which was the depth to rock bottom.. Cheers Trev