2. Except in Russia and Spain, the most productive mines are open-cuts, and mining is quickly and easily accomplished at minimum expense. Extensive operations in advance of production are rarely necessary. 3. The countries that possess the largest and richest deposits have an abundant and cheap labor supply. 4. The productive capacity of the known deposits so much exceeds the world’s demand for ore for steel making, that if any single source is temporarily eliminated, the demand can be wholly met by the remaining sources at prices that are only slightly higher than those previously prevailing. 5. The value of the material at the sources of production is relatively low among raw minerals, and ranges from one-third to one-eighth of the selling price at the points of consumption. It is evident that the cost of transportation represents a large part of the final price. 6. The working of most deposits yields so little profit, and therefore is so hazardous, that only a few foreigners own deposits in the chief producing countries. 7. The only case of commercial control, that of the Chiaturi district, Russia, by Germans, who offer the natural market, seems to have been established to counteract local political disorders rather than to eliminate competitive consumers. 8. No nation that contributes largely to the world’s steel production, except Russia, possesses domestic deposits of manganese ore sufficient to meet its needs, and all must import ore from rather remote sources. The United States and Germany, however, possess domestic deposits of ferruginous manganese ore that under great stress would probably permit independence of foreign sources. CHAPTER V CHROMIUM BY E. C. HARDER USES OF CHROMIUM Chromite is the principal ore from which metallic chromium and chromium products are obtained. The theoretical composition of chromite is represented by the formula FeO Cr₂O₃, which represents 32 per cent. ferrous oxide and 68 per cent. chromic oxide. In many ores, however, the ferrous oxide is partly replaced by magnesia, up to 30 per cent., and the chromic oxide by alumina and ferric oxide, up to 20 per cent. Thus the composition of chromite varies considerably. The percentage of chromic oxide may be as low as 10 per cent.; that of ferrous oxide may range from 10 to 50 per cent. Other common minerals of chromium are picotite (chrome spinel), uvarovite (chrome garnet), chrome diopside and crocoite (lead chromate).