Peter Alexeivitch Kropotkin and John Thomas Bealby, 1911 Encyclopædia Britannica, Volume 20… (1911)
“ Nearly one-fifth of all the copper ore extracted in Russia comes from Orenburg (about 16,000 tons annually) ; and every year 16,000 to 20,000 tons of cast iron and 11,500 tons of iron are obtained. Agriculture is carried on on a large scale, the principal crops being wheat, rye, oats, barley and potatoes. ”
