Slater was not a common surname in ireland in the 1890s and was predominently in the Dublin area in the 1890s according to the Registrar General of Irelands report of 1894 on the distibution of surnames appearing in the birth registrations in 1890.
There are alternative records that have been researched and compiled as alternatives to the registers lost in the fire of 1922, the whole of Ireland census for 1901 survives, however, if they came to build the canals you are talking over 100 years before then. Are you sure it was canals and not railways?