[en] One of the most important factors in isolating the demonstration waste storage site is an adequate number of shafts to insure proper ventilation. Proper ventilation will require that the air exhausted from the storage area pass directly to the upcast air shaft. Those mines reported by this scoping contract generally conform with the two shafts per mine requirement of MESA. Three of the mines reported on have more than two shafts. Several of the mines can have additional shafts drilled in time to meet ERDA's schedule. Rough drilling costs have been cited in the report. From an economic standpoint, it is probable that the larger the mine, the greater the economic impact with regard to any dislocation of production that may be required. In some cases, such as the Retsof Mine and the Cayuga Mine, multiple shafts eliminate the probability of dislocation. Those small tonnage mines such as the Kleer at Grand Saline, Texas; the Hockley Mine near Houston and the Lyons Mine of the American Salt Company might be leased or purchased in their entirety