The presence of very large gas resources in low permeability reservoirs of the Piceance Basin and other Rocky Mountain basins is well known. The ERDA, Mobil, and other private companies have mounted a substantial effort to convert at least part of these resources to recoverable reserves. In recognition of their common interest, Mobil and ERDA have contracted (Contract No. E(26-1)-678) to jointly fund such a project of this type. The primary objective of this project is to demonstrate the commercial feasibility of massive hydraulic fracturing (MHF) for recovery of gas from the Mesaverde formation of the Piceance Basin. This project is a continuation of work initiated by Mobil in 1971. In this prior work one well was drilled in the Piceance Basin and massively fractured.