The following report was written to replace previous directions submitted in the February 6, 1943 report on the preparation of the solution X(OC₂H₅)₅.

Abstract: "The definitions of the fundamental measures of calutron operation including enhancement, current ratio, and process efficiency are set forth with derivations of the relationships between them. An analysis of the plant process is carried out for both the tanks limited and the charge limited case. Equations are derived for plant X output and plant X utilization efficiency. Effective production is defined and the value of increment to a mass of product material in terms of effective production is determined. An equation giving the X concentration below which product material should be reprocessed is derived."

From abstract: Seismic waves resulting from a 5 kiloton nuclear detonation 1200 feet deep in a salt bed near Carlsbad, New Mexico were measured by strong-motion seismographs operated by the Coast and Geodetic Survey on the surface in the distance range from 0.5 to 8.8 miles and underground in a potash mine 8.7 to 11.2 miles distant.

Illustrations regarding the Bull Canyon District Delores Plateau Area, Colorado.

A report of the Comb Ridge Fold District in the Sand Juan Basin, Utah.

Summary tabulations of Tonnage Estimates

Figures and calculations of the Blanding District.

Index maps, detail figures, columnar sections, and calculation tables for the Carpenter Ridge District.

Tables from the Dolores River District

Figures and columns for the West Paradox District.