“How large should a placer sample be to insure an accurate determination of the grade?” This has been the subject of placer miners and evaluators for years. The geo-statisticians have weighed in with possible answers. [...]

Richard Shell has been manufacturing very large suction dredges for over forty years. Figure 1 shows the largest suction dredge in Alaska. This Shell 15-inch dredge has an overall length of 123 feet from the [...]