For the Mudcatter who wanted the 3rd verse,I sing a version which goes as follows:

In conclusion, bear in memory
Keep this watchword in your mind
God provides for every worker
When in Union they're combined
So stand up strong & stand together
Victory for you'll prevail
Keep your hands upon your wages
And your eyes upon the scale.

I agree about the Siwsann George tune - it is very close to 'Calon Lan', which I know well from years of Welsh hymn singing at school. I first heard the song sung by the group 'Offa' ( based in Wrexham, North Wales ) and it is probably closer to the 'Mountain Railway' one, though still very like 'Calon Lan'. That is the one I use. It is quite likely that emigrant Welsh miners took the hymn over to the USA and , like any good tune,it got recycled into the Mountain Railway song & thence into Miner's Lifeguard.