The water should not be jetting in like that. You do need to slow it down not the volume but, how it is jetting across the aluminium before the inspection mat you don't want that kind of "push" from the water. You are also introducing a lot of air bubbles which effects recovery of fine gold. The way the black sands are concentrating behind your riffles looks good to me.I disagree with Jason but, don't think he is wrong he just works different creeks than me. I have tried expanded and no expanded and saw no affect on my recovery. I run expanded over just vmat sometimes and I run miners moss under expanded over vmat sometims too. Sometimes I run a drop riffle. Some guys will say you need to tune your sluice to the type of gold you are "trying" to recover. I say Gold is Gold and does what it does. I tune my sluice to the type of material I am seperating gold from, and to the volume and flow of the watercourse my sluice is in.In a power sluice you can control your flow I would personally want my water a tad deeper than yours is running and I could then tune the sluice by adjusting the angle. Now to your creek....you are keeping yourself focused on if your sluice is working right when you don't truely know if this creek is going to produce enough for you to justify digging such big deep holes. You could have a decent amount in a good crack in the bedrock somewhere nearby.Is there bedrock in or next to the creek? If so get a screwdriver a paintbrush a small trowel and/or a spoon. Plop yourself down and scrape some cracks.Almost certainly that creek has flooded and gravels have washed onto this bedrock if it is exposed and if there is gold you will find some in the cracks of the bedrock. A very good way to sample.As you said you dug down and found another boulder? you are atleast a foot or MORE from bedrock in the creekbed. I would move on and find bedrock.Can you get up on the hillside and take a pic of the drainage looking down so we can see the lay of the land a little better?
