Indeed, your Sanderson b. 23-Feb-1888, is buried in Midland Road Cemetery, near Chipman, close to Drost's Bridge. The only death date I've encountered is the same as you, only the year. I suspect, if you could find someone in the Chipman area to go to the cemetery, they may have listed a more complete DOD on his stone. Interesting that his birth record apparently lists him as "Saunderson". Also have found need to look not only under COPELAND, but COPLAND as well.
Sorry I don't have the exact date.