Robert Neal Rudmose-Brown,
1922 Encyclopædia Britannica — Siberia
“ Minerals.—Gold is the most important mineral in Siberia. The Lena drainage area, especially the valleys of the Olekma and Vitim, is considered to be the richest gold-producing area in the world. All the gold worked is alluvial and the annual yield (1916) was some 400,000 oz. Bodaibo, connected by rail to the Vitim, is the centre of the industry. The gold-fields of the Amur valley when fully explored will probably prove to be even greater in extent. The new town of Zeya Frisian on the Zeya is the principal mining centre on the middle Amur. The Bureya valley is also rich in gold. ”
