NEVADA TEST SITE

The deep underground tunnel shot, code named Rainier, was fired on schedule at 10 a.m. PDT today. Its purpose was to determine the feasibility and safety of this method of testing.

Officials of the test organization, observing from a temporary forward control point two and one-half miles from the mouth of the detonation tunnel, reported immediately after the blast that there was none of the usual visible effects of surface or above-surface shots. There was no flash of light, no wave of heat, no shock wave, and no mushroom cloud.

While it is almost certain that there was a slight surface pulsation of the earth at the temporary control point, observers there felt nothing.

As had been predicted, they saw spurts of dust rising from the 7500-foot mesa top and from the slope of the mesa indicating that there had been some heaving and settling of the surface. A few weathered rocks were dislodged from the visible side of the mesa crown. There did not appear to be any spurt of dust or other debris issuing from the mouth of the tunnel, which would indicate that -- as planned -- the blast from the detonation had itself collapsed the tunnel wall and blocked the passage, trappping all radiation in the tufa.

Various preliminary conclusions may be stated on the basis of visible effects and of non-visible effects:

• The yield of the device did not exceed the announced range of 1 to 3 kilotons
  
• The 800 to 900 feet of tufa surrounding the detonation absorbed much of its energy and only a minor amount of energy was transmitted through the earth.
  
• The tufa rock successfully contained the radioactive material created by the detonation. It is improbable that any reached the surface and quite probable that none escaped into the air.
  

It will be possible to provide fairly soon an evaluation as to whether the data recording instrumentation apparently functioned satisfactorily. It will of course be weeks before all data is obtained through entry into the mirror portions of the tunnel and by drilling into the detonation chamber from the surface.

It may also be possible to obtain a better description of any physical changes in the mesa top and sides by helicopter observation.