Once the cylinder had reached the planned level of the tunnel, a further 21 feet of earth was removed and a brick wall built under the iron ring, leaving a opening on the north side 36 feet wide. Into this was fit the tunnel shield, holidng 12 frames, each housing three miners. The shield was 6 feet deep, and held up the tunnel ceiling and walls until the brick lining was extend forward to meet it. The platform on wheels on the left provided a platform for delivery of bricks and masos to the tunnel end and a route for removal of dirt excated from the tunnel face. The inset at the bottom shows a miner excating a strip of dirt 3 feet wide by about 8 inches high before replacing one of the ten "poling boards" running across the face of his compartment.

February 14, 2014