Prospectors often wonder how frequently you need to do a clean out on a sluice box. Some prefer to clean the riffles out several times per day, while others wait and do one cleanout at the end of the day. This is mostly just a matter of personal preference, but there is a reason that a person should keep an eye on how the sluice box
is functioning in order to best evaluate how we can most efficiently run material.
The most important consideration you must keep in mind when using a hand operated sluice box is setting it up properly to operate at key efficiency. For the beginner, this can take a bit of practice along with some trial and error. The goal is to add material to the head of the box which can run smoothly down across the riffles. You notice that lighter sands and gravel is getting captured in the top end of the riffles, you need more flow to discharge this lighter material out the back. This can be attained a few different ways; you can resituate the sluice in an area that has slightly more flow, you can situate the sluice at a slightly steeper angle to increase the speed of water going over the riffles, or you can add a few rocks in front of the sluice to funnel more water into the box.
Once youíve got everything set up properly, then you should have a situation where the heavier materials like black sands and gold will remain in the sluice, while the sands and gravels will move out the back.
Once you have your sluice box
properly set up, you need to keep an eye on how well it is functioning. The frequency that you do a cleanout has a lot to do with the material that you are running. If the material is loaded with heavy black sands, you will notice that the riffles will get filled up quickly, especially at the head end of the box. When this happens, they are not functioning at peak efficiency.
Under ideal circumstances, most of your cold will be captured in the first few riffle of the sluice. If you notice that much of your gold is getting caught at the bottom riffles, then you are likely losing gold out the back. This will be especially true for the fine gold that is toughest to capture.
Look at your sluice as you are feeding material. If it seems like the riffles at the head of the box are still functioning properly, then there is no need to continue do a clean-out yet. You time will be better spent feeding additional material. Understand that the key word here is efficiency. If the sluice box appears to be functioning properly then continue adding material, but if it seems like it is getting loaded down with black sands, itís time to clean it out.
Another tip that will help with your efforts is to always classify your material before running it through your sluice. This removes those larger rocks and debris out, and helps your sluice operate at its maximum efficiency. This will ensure that you capture all of the possible gold available, and reduce your losses.