There are 2 William Senogles in the earlier census data, both born approx 1850.
1. William Senogles, born Patrick, around 1850, son of John and Esther. John was described as a miner in silver lead ore mines. This William appears to marry Catherine and is described as a lead miner in 1901. His oldest son is called John.
2. William Senogles, born around 1850 in Lonan,was the son of William, a blacksmith. He married Isabella. He had a daughter age 5 in the 1891 census, called Elizabeth S. Senogles and his mother-in-law Jane Kelly lived with him too. He lived at 3, Mines Road, Agneash, right near the Snaefell mine. According to the booklet I have about the Snaefell mine disaster, the daughter was adopted.
The second William was presumably the unfortunate victim - I couldn't find him in the 1901 census.
Hope this helps!
Susan