This volume describes and summarizes the technical/engineering aspects, efforts and results associated with the Keystone Project Feasibility Study. The Keystone Project coal-to-methanol synthetic fuel plant site is located near Cairnbrook, Pennsylvania, in Somerset County. A Westinghouse fluidized bed gasification system will process a locally available, high-sulfur, caking coal into a raw synthesis gas. The gas will then be cooled, shifted and purified prior to being converted to methanol via the Imperial Chemical Industries (ICI) process. The methanol is intended for use as described in the Marketing report (Volume IV). Elemental sulfur, dry ash, carbon dioxide and liquid anhydrous ammonia will be recovered as plant by-products. The project has been sized on an economical, single-module level, processing 2330 tons per day of coal into 13,343 barrels per day of methanol. However, the project can be expanded to a total of five modules with an overall production capacity of 66,500 barrels per day of methanol when market and economic conditions warrant. The technical portion of the feasibility study for the project is divided into several major areas, and the following tasks are reported in this volume: assessment of technology, comparison studies, preliminary plant process design, instrumentation and control systems, capital and operating cost estimates, and project schedule.