Haviland had a large clay tile manufacturing plant. If you have ever been to Paulding country , you know that the nice surface farm dirt is really not that deep.
Below the thin layer is a tremendous layer of clay. The Haviland works had three huge "barrow" pits that they dug clay from. As the article states , clay tile was eventually was replaced by huge rolls of corrugated plastic pipe.
Anyway , I remember helping "ditch" several fields near our home. The process involved a rather large ditching machine that would dig a 3/4 foot deep trench in the field. A worker would lay 6 inch drain tile in the trench right behind the machine. He would knock a small amount of dirt back onto the tile. My task was to then using rake , cover the tile to a depth of 6/7 inches , and gently tamp the dirt down . This was a really neat job for an 8 or 9 year old kid. I didn't weigh enough to break any tile , and the tile handler didn't have to do that task as well as own.