A branch drain accepting waste products delivered to it vertically, by gravity, from one or more similar but usually smaller fixtures, and conducting them horizontally to the primary disposal drain.
When the Minuteman III retires, the silos and launch facilities at Malmstrom Air Force Base in Montana, which oversees 150 nuclear ICBMs scattered across a 13,800 square miles, will have been buried for 70 years.
It's quite possible North Korea has all the parts and expertise to build a nuclear-tipped ICBM that can reach the United States. However, there is only one launching pad for a Taepodong-2, and it would require hours of preparation before the missile is ready. We also don't know how reliable the rocket would be.