North Korea’s Punggye-ri Nuclear Test Site: Spring Construction and Maintenance Activities Continue

A 38 North exclusive with analysis by Jack Liu

Summary

Recent commercial satellite imagery indicates that North Korea is conducting regular spring construction and maintenance activities at its Punggye-ri nuclear test site. There are no indications of nuclear test preparations at this time. Given the time and effort such preparations require, North Korea is unlikely to conduct another nuclear test until at least fall 2015 at the earliest.

West Portal

At the West Portal, site of the 2009 and 2013 nuclear tests, commercial satellite imagery from May 16, 2015 shows no discernable changes in the spoil pile since the beginning of this year. Whether digging of a new tunnel—which began around April 2013, paused in November 2013 and resumed in February 2014—has stopped because work has been completed or has just simply paused, remains uncertain.

Figure 1. The West Portal.

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In the vicinity of the West Portal tunnel entrance, the camouflage netting that was off in a March 27, 2015 image is back in place over the West Portal tunnel entrance on May 16. In both images, there are vehicles parked near the tunnel entrance. There is a white tarp or tent over what appears to be two piles of material by the mining cart tracks near the tunnel entrance area. The material in these two piles is a different color from that of the other piles. One can only speculate why the two piles warrant covering. Perhaps the material is a form of gunite cement (commonly used to line swimming pools) to reduce water seepage from the tunnel walls. A drainage ditch to allow water to run from the tunnel entrance is quite evident.

Figure 2. Activity near the West Portal tunnel.

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The pile of logs present in the ravine at the West Portal entrance may have been cut from nearby trees (figure 3). (It is quite often the practice to leave logs in running water to wash off dirt and mud.) The stacks of cut lumber have disappeared in the May 16 image. It seems the workshop or sawmill built last year was intended to support construction activity at the West Portal and the Main Support Area. The cut lumber may have been used to construct the new building in the Main Support Area (figure 6), while raw logs and rough timber may have been used as shoring in the new West Portal tunnel.

Figure 3. Logs and lumber in the ravine at the West Portal entrance.

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Shoring reduces the pressure of the surrounding rock that can collapse the tunnel roof and walls by placing beams and posts at short intervals to reduce stress on the rock and the formation of cracks. When digging a tunnel, the process is to dig a few feet and then wedge a beam over two posts before digging further (figure 4). Once a tunnel is completed, it still needs to be maintained because water will always be dripping into the tunnel through cracks and will need to be removed through drain channels running along the floor. Nevertheless, tunnels are extremely humid and, over extended periods of time, the timbers will rot and must be replaced as part of normal maintenance.

Figure 4. A typical tunnel shored with logs.

A typical tunnel shored with logs.

Over the past 15 years, approximately 1 square km or 250 acres of forest has been logged at Punggye-ri. Figure 5 highlights the logging areas in green. The North Koreans appear to use the local wood to: 1) construct buildings; 2) provide heating and cooking; and 3) shore up the tunnels.

Figure 5. Logging areas at Punggye-ri.

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Main Support Area

Figure 6 shows the construction that has occurred at the Main Support Area since March 2015. A building has been erected in the northern part of the area and a structure to the west has been re-roofed. The piles of logs seen in March 2015 are no longer present, and some stacks of finished lumber remain.

Figure 6. Main Support Area construction.

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South Portal

Minor maintenance activity is ongoing at the South Portal. The March 27 image shows muddy truck tracks in the snow, and new lumber is visible in mid-May.

Figure 7. Minor maintenance activity at the South Portal.

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