In a recent development reported from the North Korea watchdog group 38 North. They report that:

Commercial satellite imagery of the Punggye-ri Nuclear Test Site from April 19 indicates probable trailers near the North Portal, the tunnel that North Korea appears to have been preparing for a nuclear test. While no recent dumping is observed, there are at least five mining carts along the tracks leading to the spoil pile and one probable small equipment trailer adjacent to the support building. A net canopy remains in place, presumably concealing equipment, and the pumping of water out of the tunnel to maintain an environment optimal for instrumentation and stemming seems to have ceased.