I’ve been listening to Martin Hayes playing this lovely tune on his 2006 album, but only recently felt confident enough to attempt a tune in G minor (ie B flat and E flat)! Fortunately it is a lovely tune even when played slow and the gentle hornpipe swing helps to keep it not too fast. We definitely do not have to play it as fast as Hayes and many others do and still have a beautiful tune!
The Brown Coffin is also known as the Factory Smoke (and also The Ebb Tide, Factory Smoke Clog, The Tide Come In, The Tide Comes In, The Tide Coming In, When The Tide Comes In according to thesession.org
Jon Fletcher has given us chords but also suggests easier chords by using a capo on the third fret (scroll down to see this).
Martin Hayes playing it on his 2006 album
Martin Hayes with Tommy Hayes on bodhran (but no pictures or film)
JigJam band (banjo, guitar and double bass)
The link to the pdf is here:
Brown Coffin for Capo