Gold Process Extraction Design Considerations

Always we must consider that there is a little possibility that the results from lab can not be reproduced exactly to industrial level. In the lab are feasible get trends about the metallurgical behaviour of the ore. If the results are excellent, the plant will have excellent results too, although not in the same proportion. In order to have a better idea must be carried out a pilot test, but some times that is not possible.

Tests executed in the lab are most the time done in exceptional conditions, mainly when the testwork was carry out of the mine. An ideal condition is simulate the future conditions of the operation, and this includes environmental aspects.

Start a new operation needs time for a good approximation to the results obtained in the lab. The work consists in evaluate each equipment until it can work in the best operative conditions according its design. In the lab, in order to obtain a particular mesh size in grind can be used a graph and extrapolate the required time. In a plant for obtaining a particular mesh of grind must be analyzed the grinding-classification process because during the phase of engineering were considered many aspects such as circulating load, maximum size of ball, apex and vortex diameter, speed of pumps, solids percentage, etc. All these variables have influence in obtain the wished product during grinding. The experience of designer and operators will favor the stability of the grinding circuit to the best operative conditions.

The recovery obtained in the lab must be balanced with the grade in the feed and the tails, and no must be considered any losses of gold from solutions. This loss will be minimized when the washed system of final products can be improved or perhaps with a better recycling of solution to the circuit. In the best case this loss will not be more than 0.5% and must be consider by the designer for respective evaluations.

As was mentioned, the consumption of reagents is lower in an industrial plant owe to recycling of solutions. Ergo, operative costs can be lower. Sometimes, the difficult task is calculate the amount saved but it’s possible get an idea having a mass balance.

The final optimization is done to industrial scale and during the operation. Experience of the designer and operators will save time and the final point will be got in the short time. It is unusual get the best results in the first hours of operation. It is very important have a good metallurgical laboratory in order to evaluate each part of the process and obtain the best operative conditions.