CREATE TABLE table_203_2 (id DECIMAL, "name" TEXT, "mineral" TEXT, "opened" TEXT, "closed" TEXT, "years connected" TEXT, "notes" TEXT)

how many years was the cesail mine connected ?
SELECT "years connected" - "years connected" FROM table_203_2 WHERE "name" = 'cesail'
SELECT "years connected" - "years connected" FROM "table_203_2" WHERE "name" = 'cesail'