Well
well - a cylindrical excavation with a depth (length) of more than 5 m and a diameter of more than 75 mm, drilled in rock or mineral by mechanical or non-mechanical drilling methods;
Source: Order of Rostekhnadzor dated 01.12.2011 No. 680 "On Approval of the Instruction on Application of Ventilation Schemes for Extraction Sections of Mines with Isolated Methane Drainage from the Extracted Space Using Gas Extraction Units" (Registered by the Ministry of Justice of the Russian Federation on 29.12.2011 No. 22815)
A well is a vertical or inclined mining excavation with great length and small cross-section, connecting the ore body in the subsurface with
surface of the earth
Source: "TECHNICAL DESIGN STANDARDS FOR OBJECTS OF GAS PRODUCTION ENTERPRISES AND UNDERGROUND GAS STORAGE STATIONS. GAZPROM NTП 1.8-001-2004"
(approved by Order of JSC Gazprom dated October 21, 2004 No. 93)