28. 



DR. GRIGGS: This seems to be a small cost compared to the 

 one given in the Johns Hopkins report. 



DR. CHRISTY: This looks like a most promising development. 



DR. GRIGGS: Suppose all the radioactive products in the 

 stored material had completed their disintegration, what would be 

 the recoverable value per gallon for the aluminum nitrate and other 

 salts if you could simply mine these deposits as though they were 

 natural deposits? Is it desirable to dispose of the waste so they 

 could be recovered at a later date? 



DR. TRUMAN P. KOHMAN: First of all, you couldn't possibly 

 wait for all the radioactive materials to decay. Sometimes it is mil- 

 lions of years. But I think there are some elements for which it 

 might be worthwhile to mine these deposits. There are two other 

 elements besides plutonium -- technetium and neptunium. 



DR. CHRISTY: The mining operation undertaken recently to 

 recover an element from the sludge proved to be difficult and hazard- 

 ous. These underground tanks had to be entered with remote equip- 

 ment such as pumps to sluice out that material to transfer it to another 

 tank, and it is a difficult operation. Only the extremely high value of 

 the element involved made it economically possible to support the op- 

 eration. The mining of anything in these tanks became more difficult 

 as time passes because it develops into fairly solid material. 



Our hope is to make use of the nickel ferrocyanide treatment 

 and make self- concentration fully effective so that eventually we won't 

 have to be too concerned about how long these tanks will last. It is 

 felt that a slurry will be produced, then a semi- solid mass in each 

 vessel, and then, if tank space is again required, the supernatant 

 above the sludge may be treated with something which should not be 

 difficult for the chemists to come up with, something which would 

 give a result similar to nickel ferrocyanide. 



DR. J . W . WATKINS: Can you tell us anymore about the char- 

 acteristics of cribs and units that prevent contamination of the river? 



DR. CHRISTY: The cribs are rather simple. They started out 

 to be just a hole in the ground below surface. Our ground water table 

 is quite deep -- on the order of 350 feet -- and these cribs were con- 

 structed close to the surface. The top was just a timbered structure, 



