(snip)
“This first tunnel was about 3 by 4 feet (0.9 m × 1.2 m) and extended over 1,000 meters (3,300 ft) beyond the Military Demarcation Line (MDL). When the first tunnel was discovered, it was reinforced with concrete slabs, electric power and lighting, weapons storage and sleeping areas and had a narrow gauge railway with carts, capable of allowing approximately 2,000 soldiers per hour to traverse it. The second was discovered on March 19, 1975, of similar length, between 50 and 160 meters (160 and 520 ft) below ground, but was larger than the first, approximately 2 by 2 meters (6.6 ft × 6.6 ft). The third tunnel was discovered on October 17, 1978. Unlike the previous two, the third tunnel was discovered following a tip off from a North Korean defector. This tunnel is about 1,600 meters (5,200 ft) long and about 150 meters (490 ft) below ground. A fourth tunnel was discovered on March 3, 1990. It is almost identical in structure to the second and the third tunnels.[6]
The tunnels were dug by North Korea and are presumed for use by the military as an invasion route. Each tunnel is large enough to permit the passage of an entire division in one hour. All the tunnels run in a north-south direction and do not branch off. The planning for the tunnels got progressively more advanced (for example, the third tunnel slopes upward slightly as it progresses southward, so that water does not stagnate). The orientation of the blasting lines within each one indicates that North Korea dug the tunnels. Upon their discovery, the North claimed that they were for coal mining; however, no coal can be found in the tunnels, which are dug through granite, but some of the tunnel walls were at some point painted black to give the appearance of coal.”
They Be Diggin’...;0)