Show Preliminary Shock Effects Reported on Nuclear Detonation Preliminary scientific data from the theMay theMay 1 May ay 17 Project Rio Blanco Dianco nuclear detonation de indicates that the extent of spall shall caused by the explosion fell well within predicted limits and that it did not damage oil shale deposits Spall is an underground effect caused caused cau cau- sed by the reflection of shock waves traveling traveling tra tra- tra- tra upward from the explosion back downward from the grounds ground's surface Spall Span has been a major concern because because be be- cause of its possible effect on the oil shale lying above the detonation point in inthe inthe inthe the Basin INITIAL SPALL measurements were outlined in a D plus 2 Day Report issued by Dr Charles Williams project director for the U U U. S S. S Atomic Energy Commission and Gerald Luetkehans Luetkehans Luetke Luetke- hans project director for clear Corp Corporation All necessary spall span measurement data was received from Instruments within one second after the detonation of three 30 nuclear explosives more than a amile amile amile mile underground some some 30 miles southwest southwest south south- west of Meeker Colorado Evaluation of the data will continue to further refine refine re reo re- re fine the preliminary spall measurements THE OIL shale layers of primary concern concern con con- cern lIe between and feet beneath beneath beneath be be- neath the surface at the Rio Blanco Blan o well Preliminary data indicates tes that the spall effect at the well wen extended more more than feet but less lesS' than feet teet down according to the D plus 2 2 Day Dy Report Further evaluation of of data dat from instruments located at and feet down will refine the range of according to project John To To- Tom Toman m man n of the Livermore Laboratory detonation Pro n estimates were that spall would extend 1 no deeper than S O feet and that it if w would uld more likely be limited to about feet down at theand the theand theand and feet down at feet out from the well AT 2600 feet away from the well the D plus 2 Day Report states that spall fell feU between n and fe feet t do down and that it was measured between well |