placer mining การใช้

• The last large nugget uncovered by placer mining was discovered in 1896.
• The main occupation of the settlers was mica mining; later placer mining.
• It was used as a source of water for extensive placer mining.
• Placer mining gave out by the 1860s, replaced by hard rock mining.
• "Dredging " is a method for placer mining below the water table.
• Hydraulic mining became the largest-scale, and most devastating, form of placer mining.
• The brothers tried placer mining but soon opened a trading post.
• Even the earliest photos are about bridge construction and placer mining.
• From Nebraska he moved to the placer mines in the Dakotas.
• Placer mining in the area continued into the later 19th century.
• Placer mining had always been hampered by a heavy brown sand.
• Quartz mining predominated but there was some placer mining as well.
• Reed continued with placer mining for a number of years.
• He settled in the capital of Montana Territory, Bannack, Montana, and began placer mining.
• The district produced nearly a half million ounces of gold, all from placer mines.
• Placer mining has been reported for every year since 1894.
• He later worked at placer mining, at railroad construction and as an employment agent.
• Placer mining operations have been noted at several locations in the river since 1969.
• Recreational mining is often small-scale placer mining but has been challenged for environmental reasons.
• Placer mining was also practiced and continues today on the banks of the North Yuba.