good educated guess by cooky

Bu the fact is, above the artic circle, the first 40 to 60 feet of rock is fracutured caused by the thaw and freese of the artic weather. The portal to Workman's Bench tunnel had to be shored-up with timber to reinforce this area of fracutered rock and then by law/regulations the company had to let it stand for a period of time, through summer warm weather, as required to see if the portal is stable and safe to allow for workers to carry on mine production. During this period of time, by law, no mining activity is allowed. As far as I know, the tunnel has passed this test; I haven't heard a word about structual failer.

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