 In the next stage, by 1853, hydraulic mining was used on ancient gold-bearing gravel beds on hillsides and bluffs in the goldfields.In a modern style of hydraulic mining first developed in California, a high-pressure hose directed a powerful stream or jet of water at gold-bearing gravel beds.The loosened gravel and gold would then pass over sluices, with the gold settling to the bottom where it was collected.