I've done it. Hard, slow, it's not easy to find the right steels either. Various references typically indicate a single-edge or cruciform bit about 20mm in diameter, smaller than modern steels because gunpowder doesn't require a standard diameter and its limited explosive force benefits from a small hole
Most photos show miners working in pairs with one swinging a two-handed hammer of about 10lb, hence the traditional song "Nine Pound Hammer" although larger ones were common, 14-16lb being a common size and the legendary hand-driver John Henry was said to use a pair of 20lb hammers. This may be a reference to a three-man team, with two men hammering simultaneously or alternating.
''the stopes soared beyond the range of our caplamps' - David Bick...... How times change .... oh, I don't know, I've still got a lamp like that.