| 31. | First the line was marked over the ridge and a series of vertical shafts were bored.
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| 32. | The Virgilius Chapel lay directly underneath this chapel, and a vertical shaft connected the two buildings.
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| 33. | With access to a local Tommy shop, they sank 14 vertical shafts during the tunnels construction.
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| 34. | For removing debris, air circulation and light at approximately every 50 meters, vertical shafts were constructed.
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| 35. | The vertical shafts support construction and maintenance of the underground channel as well as air interchange.
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| 36. | The building utilizes five vertical shafts as an integral part of the ventilation and cooling strategy.
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| 37. | There was a bevel gear and a vertical shaft passed through the floors to each storey.
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| 38. | The recordings made by Gulam Yazdani indicated the existence of 21 vertical shafts or air vents.
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| 39. | A vertical shaft beneath the millhouse connects the grindstones with a " tub wheel " turbine.
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| 40. | The Union retort is a vertical shaft retort.
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