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Descriptions of structures and facilities listed above are presented in the following <br />sections. <br />Mine Portals Dorchester constructed the Southfield Mine portals, excepting the <br />South Fan portal, in late 1978. Portal development involved excavation of a mine <br />face-up area, placement of excavated material in adjacent low-lying areas to create <br />a relatively level mine yard area, construction of portal structures, and development <br />of five parallel mine entries into the Red Arrow coal seam. Portal structures include <br />concrete foundations or slabs with structural steel support members to provide <br />ground control and protect men and equipment. The five mine slope entries, as <br />illustrated by Figure 18, Mine Portals, are utilized for intake and return ventilation <br />airways, movement of men, materials and supplies into the mine, and belt haulage <br />of coal from the mine. Roof support and ground control in the main entries consists <br />of roof bolts and wire mesh, gunite concrete, and structural steel supports where <br />appropriate. <br />Entries Nos. 1 and 4, shown on Figure 18, Mine Portals, utilized as returns for <br />ventilation discharge from the mine, are connected to mine ventilation fans. Entries <br />Nos. 2 and 5 are air intakes for the mine <br />2.05.3-19 Revised 5/13/04 <br />Permit Renewal RN-04 <br />