What is "sump men"

Sump \Sump\, n. [Cf. G. sumpf a sump in a mine, a swamp, akin to LG. sump, D. somp a swamp, Dan. & Sw. sump, and perhaps to E. swamp.]

1. (Metal.) A round pit of stone, lined with clay, for receiving the metal on its first fusion.
   --Ray.

2. The cistern or reservoir made at the lowest point of a mine, from which is pumped the water which accumulates there.

3. A pond of water for salt works.
   --Knight.

4. A puddle or dirty pool. [Prov. Eng.]

   Sump fuse, a fuse used in blasting under water.

   Sump men (Mining), the men who sink the sump in a mine.