Even though standard churn drilling techniques may be recommended in placer gold sampling programs, other methods may prove to be more satisfactory. It is necessary that other methods also be considered in an attempt to lower costs. The time required to drill a hole must be considered too, especially in the evaluation of potentially large economic auriferous gravel deposits.
Each placer deposit may have certain characteristics and ultimate requirements which will prevent any one technique from being considered "best". Consequently, several types of evaluation methods are described.