Complex sentence: The visitors' centre closed in 2003 until recently however, the tours were restarted during 2013 with 2 to 3 tours running daily Monday to Friday at no cost to the visitors.
Split into simpler sentences: The visitors' centre closed in 2003 until recently. The tours were restarted during 2013 with 2 to 3 tours running daily Monday to Friday at no cost to the visitors.