It was extensively worked in the earlier part of the 20th century but extraction operations have been in decline since the mid- 1970s.
Extraction operations have been in decline since the mid- 1970s. It was extensively worked in the earlier part of the 20th century.
It was extensively worked in the earlier part of the 20th century. Extraction operations have been in decline since the mid- 1970s.
It was extensively worked in the earlier part of the 20th century. Extraction operations have been in decline since the mid- 1970s.