CREATE TABLE table_203_2 (id NUMBER, "name" CLOB, "mineral" CLOB, "opened" CLOB, "closed" CLOB, "years connected" CLOB, "notes" CLOB)

the ffestiniog railway serviced at most how many slate quarries ?
SELECT COUNT(*) FROM table_203_2 WHERE "mineral" = 'slate'
SELECT COUNT(*) FROM "table_203_2" WHERE "mineral" = 'slate'