air-lift dredge

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June 18, 2026

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An air-lift dredge is a type of dredge that uses compressed air to move sediment and water. It operates by injecting air into a submerged pipe, which reduces the density of the fluid column inside. This causes the air-water mixture to overflow the top of the pipe, drawing more water and sediment into the bottom. Air-lift dredges are known for their simplicity, as they have no submerged moving parts, and can have substantial capacity for lifting solids. Dredges, in general, are large floating devices used for underwater excavation for various purposes, including maintaining depths in waterways, creating new land, constructing control works, and recovering valuable deposits.12

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Marine beaches and continental shelves
Also effective are air-lift dredges, which operate by injecting compressed air into a submerged pipe at about 60 percent of the depth of submergence. This reduces the density of the fluid column inside the pipe so that, if the top of the pipe is not too far above…
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Also effective are air-lift dredges, which operate by injecting compressed air into a submerged pipe at about 60 percent of the depth of submergence. This reduces the density of the fluid column inside the pipe so that, if the top of the pipe is not too far above…
Read More