There's a "sample" on the web site of Wynn Gogol, the engineer who mixed the album—but the "sample" is nearly 3 minutes long. It sounds like it could be the whole song. That's what I transcribed.

It sounds like a description of an accident at a sawmill in which a boy lost a hand? I suppose the blackbird is just there for atmosphere. I'm not sure about "plying". Maybe it has something to do with making plywood. Or maybe it's "planing"?

THE MILL
Pharis Patenaude

Deep hole, a deep hole,
Blackbird, a blackbird,
A deep hole, a deep hole,
Down past the mill, down past the mill,
I'm comin' on home in my good time.

A sharp blade cuttin' hard,
A sharp blade cuttin' hard,
Long haul through the yard
Down past the mill, down past the mill,
I'm comin' on home in my good time.

Roll back, roll back,
Like an oxblood, an oxblood.
My hands are full of saw wood,
Down past the mill, down past the mill,
I'm comin' on home in my good time.

Draw near, draw near.
A boy's down, a boy's down.
Plying (?) for a week now,
Down past the mill, down past the mill,
I'm comin' on home in my good time.

One hand, one hand,
Lost one hand, one hand,
One on the engine,
Down past the mill, down past the mill,
I'm comin' on home in my good time.

Down past the mill, down past the mill,

Deep hole, deep hole,
Blackbird, a blackbird,
Deep hole, deep hole,
Down past the mill, down past the mill,
I'm comin' on home in my good time.

[As sung by Outlaw Social on their EP "Outlaw Social."]