Note 108 — Chapter XIV · COPPER By F. W. Paine

Extension is the product of “Percentage of World Total” and “Developed Reserves in Terms of Years Life,” and gives total ultimate relative importance of different countries.

[109] In so far as it affects production this high figure must be discounted because of the large reserves being compact, the distance from market and the unfavorable mining conditions of a thinly settled country.

[110] Katanga equals ⁶⁵⁄₆₆ of this.