The term 'mine layer' refers to a person or machine that is responsible for laying mines. A mine is an explosive device that is placed in the ground and detonated when triggered. The crossword solutions for this term are SEAM (4 letters), ORE (3 letters), and SAPPER (6 letters). SEAM is a noun meaning a thin line of stitches used to join two pieces of fabric together. ORE is a noun meaning a mineral or rock from which a valuable metal or other material can be extracted. Sapper is a noun meaning a soldier who is trained to build and repair fortifications, lay and clear mines, and perform other engineering tasks.