The term “operating variable” is what I use when I refer to any condition that effects the operation and is subject to change. As a simple example tonnage, which is the amount of ore that the mill can process at any one time, is controlled by the operator. Because it can be increased or decreased it is considered an operating variable.
Unlike doing a circuit check, which, on the whole, is watching for circuit malfunctions these two are concerned with the process itself. An operator should always be aware of any change in his circuit. It could be something simple such as a drop in tonnage or perhaps something a little more complicated like as a change in the mineral makeup of the ore itself. In some circuits, chemicals and other supplies are required, these have to be checked, mixed and added at a prescribed rate. Again this will be an operator’s responsibility.
To maintain his or her circuit an operator must always be aware of what is happening within the process. This means that all the required readings and tests “be taken, remember once the ore is in the circuit it is committed. If a mistake is made the process cannot he stopped and redone to correct the mistake.
I think it is a good idea to keep this thought in the back of your mind when operating. A milling operator holds the dubious distinction of controlling the last stage of mineral concentration. A mistake here means losing the mineral permanently, not only will the value of the ore he lost, hut the entire cost of mining that ore will he gone as well.