CREATE TABLE table_203_839 (id DECIMAL, "station" TEXT, "type" TEXT, "latitude" TEXT, "longitude" TEXT, "el.  ( m ) " DECIMAL, "opened" DECIMAL, "closed" DECIMAL, "coordinates" TEXT)

how long did the mount harquahala , arizon station operate ?
SELECT "closed" - "opened" FROM table_203_839 WHERE "station" = 'mount harquahala, arizona'
SELECT "closed" - "opened" FROM "table_203_839" WHERE "station" = 'mount harquahala, arizona'