What are 2 types of diamond mines?

Answer 1

Diamonds are mined around the volcanic pipe that erupted them out of the earth's mantle. Generally, this means that diamond mines are circular and conical in their shape, the cone being inverted.

Also, diamonds are found away from the pipes, having been moved by running water. These diamonds -- alluvial diamonds -- are found in beds where water flows or has flowed, from the pipe to the outlet of the water, sometimes in the sea.

Alluvial diamonds mined at the mouths of rivers are scooped up with the seabed and sorted, then, from the surrounding materials like the diamonds in conical mines are sorted.