Dark as a Dungeon

Does anyone know phrase "sit in coalmine"? It is a part of lyrics in one song, and I just wanted to know if it has a meaning, because it doesn't make sense otherwise. It might also be some slangy expression.

often song lyrics are unclear - indeed there is a whole internet site devoted to misheard lyrics at kissthisguy.com (I recall).
If you tell us the song or more of the surrounding words, we can then clear it up for you.

(I do know of an old song "working in a coal mine" by Lee Dorsey, I think)

Just checked - it was Lee Dorsey -lyrics as follows :

Workin' in a coal mine
Goin' down down down
Workin' in a coal mine
Whop! about to slip down
Workin' in a coal mine
Goin' down down down
Workin' in a coal mine
Whop! about to slip down
Five o'clock in the mornin'
I'm all ready up and gone
Lord I am so tired
How long can this go on?

I'm workin' in a coal mine
Goin' down down down
Workin' in a coal mine
Whop! about to slip down
Workin' in a coal mine
Goin' down down down
Workin' in a coal mine
Whop! about to slip down

Cos I'm on call in the mornin'
Oh I go by the coal
But when Saturday goes around
I'm too tired for havin' fun (Too tired for having fun)

I been workin'in a coal mine
Goin' down down down
Workin' in a coal mine
Whop! about to slip down
Workin' in a coal mine
Goin' down down down
Workin' in a coal mine
Whop! about to slip down

Lord I am so tired
How long can this go on?

I'm workin' in a coal mine
Goin' down down down
Workin' in a coal mine
Whop! about to slip down
Workin' in a coal mine
Goin' down down down
Workin' in a coal mine
Whop! about to slip down

Five o'clock in the mornin'
I'm all ready up and gone
Lord I am so tired
How long can this go on?

I'm workin' in a coal mine
Goin' down down down
Workin' in a coal mine
Whop! about to slip down
Workin' in a coal mine
Goin' down down down
Workin' in a coal mine
Whop! about to slip down

Cos I'm on call in the mornin'
Oh I go by the coal
But when Saturday goes around
I'm too tired for havin' fun (Too tired for having fun)

I been workin'in a coal mine
Goin' down down down
Workin' in a coal mine
Whop! about to slip down
Workin' in a coal mine
Goin' down down down
Workin' in a coal mine
Whop! about to slip down

I have to add:

DARK AS A DUNGEON
Merle Travis

Come all you young fellers, so young and so fine
And seek not your fortunes way down in the mine
It will form like a habit and seep in your soul
'Til the stream of your blood flows as black as the coal

It's dark as a dungeon and damp as the dew
Where the dangers are double and the pleasures are few
Where the rain never falls and the sun never shines
It's dark as a dungeon way down in the mines

There is many a man I have seen in my day
Who lived just to labor his whole life away
Like the fiend with his dope and the drunkard his wine
A man will have lust for the lure of the mine

It's dark as a dungeon and damp as the dew
Where the dangers are double and the pleasures are few
Where the rain never falls and the sun never shines
It's dark as a dungeon way down in the mines

I hope when I'm dead and the ages shall roll
That my body will blacken and turn into coal
I will look from the door of my heavenly home
And pity the miner a' diggin' my bones. . .