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| upcast air shaft; return shaft (uptake ventilating shaft, upcast (air) shaft, upcast ventilating shaft, upcast (ventilating) stack, return air shaft, outtake, outlet shaft – АД); return shaft (uptake ventilating shaft, upcast (air) shaft, upcast ventilating shaft, upcast (ventilating) stack, return air shaft, outtake, outlet shaft Alexander Demidov) | |||