Operating a Sluice Box
A sluice box operated for long periods without any new augmentation of materials has an increase in its possibilities of losing some of the value of fine gold. The loss amount will depend on a series of factors, such as the type of design of the rifles, how much flux is there, the type and weight of the concentrates and the size and purity (specific gravity) of the existing gold.
Even when a sluice box has been built properly, occasional large-size stones and rocks can stay trapped within the riffles. These will be extracted from the riffles with the least possible disturbance towards the remaining portions of the sluice.
In the majority of suction dredges the volume of water moves through the sluice at the same steady flux as the production speed. So change in speed of water is done through the inclination of the sluice box, which will make the speed of water to increase or decrease on the box.
It is different when one works with a single sluice box that is placed in a creek or brook to be able to use its flux of water. In this case, speed of water can be adjusted by either changing the inclination of the box, varying the volume of water that is directed through the box, or by putting the sluice in the different locations within the creeks and or brooks in which water is flowing at different deeps and speeds. Getting the proper flux so that it goes through a sluice box located outside the field is not difficult. But sometimes it is necessary to try different ideas to find what works better in each of the situations. For example, in a place in which water moves slowly, one could try to direct more water through the sluice and thus gain the volume of water needed to achieve the right speed.
In a creek where the flux moves faster than the speed of water that goes through the box can be adjusted through the change in the volume of water going through the same, and or through the variation of its downward inclination. Generally, there are very few problems in reaching the right speed that should go through the sluice box when placed in a fast water creek. One can use the river rocks to make a base at the bottom of the creek so that the box is leveled from side to side. By allowing different amounts of water volumes through the box and by changing its inclination downwards, one can find the ideal combination to achieve your goal. It would be good to have a nylon rope on you to fix the sluice box to a rock or some other object upstream. This must prevent the box to move out of the base because of a strong stream of water. Sometimes t is necessary to pile up rocks over the box to keep it place. This happens when a sluice made of wood is used. Shovel gravel in a box while trying out different combinations to know which of the effects that will happen when there are changes in the speed of water.