21. "' Fire-setting "'is a method of traditional mining used most commonly from underground workings without adequate ventilation. 22. A adit was cut in the 1890s, which provided natural drainage for much of the underground workings . 23. This did not prevent Queen Victoria visiting the underground workings on an 1846 visit to Polperro . }} 24. Surface quarries were also opened; they outlasted the underground workings and were last used in the early 1920s. 25. Shortly after their arrival, Pineiro was engrossed in the pro-Castro underground working to overthrow the dictator Fulgencio Batista. 26. The project includes an open pit, underground workings , historic support facilities, a new concentrator and recently constructed tailings facility. 27. Such methods could be very effective in opencast mining, but fire-setting was very dangerous when used in underground workings . 28. There are many ancient open pit and underground workings that show that this area has been mined in the past. 29. He lived on Oak Island for a summer and possessed firsthand knowledge of the underground workings through his own observations. 30. At its peak, during World War I, Westville boasted three underground workings ; the Black Diamond, the Acadia, and the Drummond.
