Watch the Miner's Lament online guitar lesson by David Blacker from Lone Wolf Blues
Miner's Lament PT 1 is a basic 12 bar blues in the key of E minor accompanied with a steady bass rhythm. Even though on each chord change you are only really playing the low strings for the steady bass and the top two strings for the melody I still recommend getting in the habit of fingering the full Em and Am chords at least on the I and IV chords. It's okay to use a simpler chord fragment variation for the V chord because it's not an open chord. The reason for this is that fingering the whole Em and Am adds a little fullness to the sound because even though you are just thumping the one low string for the steady bass, it still resonates a bit on the higher strings if they are in the form of a chord. The only other things I would like to point out is take note of the I to V chord substitution in measures 3, 7 and 11. It gives the tune movement and is meant to illustrate some of the key places that this substitution can work.
Recommended listening: St. James Infirmary performed by Arlo Guthrie.