Schema: CREATE TABLE table_name_15 (year INTEGER, death_toll VARCHAR, cause VARCHAR, colliery VARCHAR)
Question: Count the lowest Year which has gas explosion, Colliery of tylorstown colliery, and a Death toll larger than 57?
SQL: SELECT MIN(year) FROM table_name_15 WHERE cause = "gas explosion" AND colliery = "tylorstown colliery" AND death_toll > 57