Great Laxey Metal Mine Laxey, Douglas
There is a also a Mining website with this information.
(Kelly, Robert, aged 58, Miner, the men were charging or stemming a hole into which they had put a considerable quantity of powder; they put in more than usual to fill a loch or natural cavity which the borer had entered and by some means unexplained the powder exploded killing them both; they appeared to have been using an iron stemmer)
Source [www.dmm.org.uk/names/a1875-06.htm]