Did you know that fine gold recovery often makes up for most of the gold found by small-time prospectors? It is much more abundant and is generally found in places that are easier to get to. The problem with fine gold is that its very small and poorly installed gate boxes can inadvertently let it through. To remedy the problem one must be aware of the main factors involved. The speed and volume of the water are critical! Even in a poorly designed gate, if you have the volume and speed of the water dialed in, it will still trap gold more effectively than using a high-end professional gate that is poorly set up. In addition, the angle at which the gate boxes are placed is also very important. The angle will affect the speed of the water as it descends, as well as how quickly the gate can be cleared. If the angle is too shallow, larger rocks and chunks of clay can settle on or around the rapids and cause turbulence in the water that will effectively kill the back eddy action created by the rapids. That Will make you lose gold! These points being the most critical, the next one is the construction and design of your lock. Their ability to catch gold and specifically fine gold is largely decided by the designs of the rifles or catch mat systems.
Finding the right water flow and speed for your circumstances is absolutely essential. It can be complicated and may require you to block the flow of water from your lock inlet or bring in additional water. This can be accomplished by making a small rock dam in the stream or river bed. Depending on where you are prospecting, this could be considered a violation of local Fish and Game laws, so be careful with them. Chances are, if moving rocks in the stream bed is considered a violation, so is using a gate box. Make sure you know the laws!
The larger the volume of water, the better, and generally speaking, it doesn’t hurt to fill the airlock with water to the top of the sides if possible. A good recommended minimum depth is about 2 inches. The volume is usually separate from the speed of the water, so you can easily adjust it by lowering the gate further into the water, or by finding deep spots in the stream bed that act as a funnel for your gate.
Proper flow can be judged using small stones or a handful of sand. Place it at the entrance of your lock and watch it flow. all but the heaviest particles should be washed out within 3-5 seconds depending on the length of the gate. 3 is a bit fast but will allow much faster production of concentrates at the cost of losing some fine gold. 5 is a little long or almost right depending on the coarseness of the material you are pouring. You should be catching a lot of fine gold at that speed, but you run the risk of larger rocks getting caught in the rapids and disrupting the flow. However, you can adjust the angles to fix that.
When installing a gate the proper angle must be observed. It is typically 5-7 degrees incline and should allow most round rocks and pebbles to pass through easily. You don’t want the material to slide, but to move slowly. An ideal speed is for a larger rock to clear itself within 3 to 5 seconds in a medium-sized gate box. Also remember that the angle affects the velocity of the water as it travels down the gate. Also, it is sometimes impossible to get the angles right if the stream is very flat. In such a circumstance, you may need to create a makeshift dam with more rocks to raise the water level on one side so you can feed it through your lock. But that can be a lot of work, and it’s usually best to try to increase the speed of the water.
With the right angle, water flow, and speed, now is the time to use our gate boxes! Many people pre-select their material before feeding it through the gate. It’s a lot of work and a properly configured gate doesn’t need this. However, with that being said, if you don’t pre-screen or sort material, you are likely to lose Some fine gold. This problem can be fixed by using a sort screen above the lock entrance while shoveling dirt. I used an old dishwasher rack I found in the creek bed and put it in the entrance of my lock box. the water went right through it and as I throw the material away it washes it away leaving the larger rocks and chunks of clay for me to throw away easily. It’s a great lightweight solution that really speeds up my production. It’s also a much better alternative to dry-filtering the material directly at the dig site and then hauling it over 10 feet to my lock. Your results may vary, but at this point you should have a pretty good intuition about the possibility of losing gold.
Pulling the gate out of the stream can be a tricky process and will inevitably lead to the loss of some gold. It is strongly recommended that as you remove the gate from the water stream, place a bucket or tray at the end to catch any that may be accidentally washed away. I have seen unsuccessful attempts to remove a gate that cause small chunks of gold to be washed out and returned to the stream. Be very careful.
After that, clean up is a doddle and not to mention fun. You can finally see how all your hard work paid off. However, it’s worth noting that if you have one of the state-of-the-art plastic airlocks, you often have the added benefit of even easier cleaning, as well as a good view of what accumulates during the airlock process. The disadvantage is the lower production capacity.
Hopefully that gets any new prospector started! I hope you enjoyed my guide!
