From introduction: The purpose of this study was to investigate the quantity and quality of [Central Ceara, Brazil] magnesite, and the writer concludes that this group of deposits constitutes one of the major reserves of high-grade magnesite in the Western Hemisphere. The ore could be used in the production of any commercial grade of magnesia with little or no beneficiation. Soil and alluvial overburden is thin between widespread outcrops, so all the deposits could be mined from open pits.

From abstract: This report summarizes the economic possibilities of the tin deposits of the Estado de Durango, Mexico. It describes in detail many deposits in the leading districts, which were examined in 1944, and briefly reviews some reports on undeveloped occurrences in the southern and western parts of the State. The general conclusion is that tin will continue to be produced by hand methods for many years, but probably at a decreasing rate, because the placer grounds which have always produced the greater part of the tin are faced with gradual exhaustion.