Santa Bárbara (also known as Nel Pozu Maria Luisa and Santa Bárbara Bendita) is a traditional song of the Asturian coal miners.
The song.
The deeply emotional lyrics and the sorrowful and heroic score, usually sung a cappella by a male choir, turned the song into a symbol of Asturian coal mining and of mining in general. Sometimes used as a working class anthem, the hymn was widely used during the Asturian miners uprising of 1934 and during the Spanish Civil War.
The lyrics (usually sung in Asturian, Spanish or a mixture between both languages) describe the painful returning home of a miner, covered in the blood of his fellow miners, who tells his wife ("Maruxina") of a mining accident in the famous Asturian mine known as "Pozu Maria Luisa" (located in Ciañu, Langreo). 
Coal mining, which is present in Asturias since the 18th century having a pivotal role in the historical economic activity of the region, is known as a very dangerous activity. Historically, hundreds of miners have died in the mines of Asturias and deadly mining accidents were sadly common in the miner population.
Santa Bárbara is nowadays considered to be an important piece of Asturian traditional music and is included prominently in the Asturian folk music repertoire. The song is also often used in funerals, tributes and memorials.
Nel pozu María Luisa
Trailarai larai, trailarai
Nel pozu María Luisa
Trailarai larai, trailarai
Morrieron cuatro mineros
mirái, mirái Maruxina, mirái
mirái como vengo yo
Traigo la camisa roxa
Trailarai larai, trailarai
Traigo la camisa roxa
Trailarai larai, trailarai
De sangre d'un compañeru
Mirái, mirái Maruxina, mirái
mirái como vengo yo
Traigo la cabeza rota
Trailarai larai, trailarai
Traigo la cabeza rota
Trailarai larai, trailarai
Que me la rompió un barrenu
Mirái, mirái Maruxiña, mirái
mirái como vengo yo
Santa Bárbara bendita
Trailarai larai, trailarai
Santa Bárbara bendita
Trailarai larai, trailarai
patrona de los mineros
Mirái, mirái Maruxina, mirái
mirái como vengo yo
Patrona de los mineros
Mirái, mirái Maruxiña, mirái
mirái como vengo yo
In the María Luisa pit //
"Trailarai larai, trailarai"
In the María Luisa mine
"Trailarai larai, trailarai"
Four miners have died
Look, look Maruxina, look
look how I'm coming home
My shirt has turned red
"Trailarai larai, trailarai"
My shirt has turned red
"Trailarai larai, trailarai"
Stained with the blood of a fellow miner
Look, look Maruxina, look
look how I'm coming home
My head has broken
"Trailarai larai, trailarai"
My head has broken
"Trailarai larai, trailarai"
It was broken in a blast
Look, look Maruxiña, look
look how I'm coming home
Blessed Saint Barbara,
"Trailarai larai, trailarai"
Blessed Saint Barbara
"Trailarai larai, trailarai"
Patron saint of the miners
Look, look Maruxina, look
look how I'm coming home
Patron saint of the miners
Look, look Maruxina, look
look how I'm coming home
English translation.
A last couplet, sometimes omitted because of non politically correct profanity runs likewise
Cago en los capataces
Arrivistas y esquiroles
(Variant) Accionistas y esquiroles
I Crap on the foremen
(they're all) hustlers and union scabs
(variant) And the shareholders and unions scabs too