In longwall mining, the coal cut down by the shearer is transported by the armored face conveyor (AFC), which is laid on the floor parallel to the face across the full-face width. The chain assembly in the AFC runs endlessly from the tailgate to the headgate T-junction, where the coal is transferred to the entry belt conveyor through the cross frame, and then onto the mobile stage loader. In the early years of longwall introduction, coal transfer at the headgate T-junction evolved from the end or T discharge in the 1960s and 1970s through the side discharge and angle frame in 1980 to the cross frame in 1982. The cross frame was developed to eliminate the problems traditionally experienced with the transfer of coal from the AFC to the stage loader, in that it reduces carry-back and increases the AFC efficiency.