Report issued by the U.S. Bureau of Mines discussing the costs and methods of uranium mining in San Juan County, Utah. History, geology, and production of the uranium mines are presented. This report includes tables, maps, illustrations, and photographs.

Progress is reported in studies directed toward an understanding of the mechanism of control of red blood cell formation. A relatively rapid and sensitive method of assay for erythropoietin was developed, using the rate of incorporation of iron-59 into the red cells of normal, hypophysectomized, or starved rats as a measure of the rate of erythropoiesis. Factors that control erythropoiesis through control of production of erythropoietin were studied. The effect of erythropoietin in initiating marrow activity was demonstrated in mice having a completely suppressed marrow as far as red cell formation is concerned. Data are reported from studies on the effect of cobalt in polycythemia, the site of erythropoietin production, the clinical significance of erythropoietin, the production of erythropoietin by fetuses in utero, the effect of erythropoietin on iron absorption, and the properties of erythropoietin isolated from plasma. A list of publications during the period is included. (C.H.)

Introduction: Atomic Energy Facts is designed to serve as an introduction to nuclear operations in the United States and as a handbook of related information for the use of industrial firms and other active or interested in atomic energy.

Report presenting a compilation of most of the zero-lift drag obtained from free-flight measurements on fin-stabilized bodies of revolution. Results regarding friction drag, base pressure and base drag, pressures on a forward facing step, and fin pressure drag are provided.