376 18.Economic and Environmental Considerations plastics are even more utilized than Figure 18.2 might suggest because the presented data are based on weight rather than on volume.Figure 7.2 depicts the world steel production. 18.3●World Reserves Next,the future availability and the remaining world's supply of raw materials need to be taken into consideration when design- ing an industrial product.Table 18.2 lists some data concerning current world productions and known world reserves for some minerals.Table 18.2 also reveals the number of years these sup- plies are projected to last if usage proceeds at the present rate and no new sources are discovered.As probably expected,iron, oil,and coal top the list by far with respect to world production. Some forecasters predict an exponential growth of usage for some materials.This would deplete the resources much faster than the above-assumed constant level of consumption.A spe- cific time interval,tp,may be defined,during which future con- sumption is predicted to have doubled,that is,tp=69/r,where TABLE 18.2.Annual world production and estimated world reserves of materials(data in 106 metric tons except for crude oil,which is given in 109 barrels (bbl),whereas 1 bbl of oil is 0.159 m3 or 0.18 tons).The production data are for 2000 and the world reserves from 2001/02 World World Years' Materials production reserve base supply Iron ore 620 160,000 258 Copper 13.0 650 50 Aluminum 30.1 6,600- 219 Lead 6.0 130 22 Zinc 8.8 450 51 Tin 0.3 11 37 Nickel 0.9 140 155 Silicon 4.5 Essentially unlimited Potash 25.0 17.000 680 Phosphate 41.4 37,000 894 Crude oil 27.9 1,047.5 38 Coal 4,343 984,453 227 World iron ore reserve base:330,000 X 106 tons.Two tons of iron ore yield approximately one ton of iron.Note:Scrap iron is not included. bBauxite world reserve:33,000 X 106 tons;Bauxite yields 1 ton of Al from 4 to 6 tons of ore. Sources:USBM,Mineral Commodity Summaries 2002,"World Oil,"Au- gust 2002,for crude oil,and "1999 Survey of Energy Resources,"World Energy Council for coal.plastics are even more utilized than Figure 18.2 might suggest because the presented data are based on weight rather than on volume. Figure 7.2 depicts the world steel production. Next, the future availability and the remaining world’s supply of raw materials need to be taken into consideration when design￾ing an industrial product. Table 18.2 lists some data concerning current world productions and known world reserves for some minerals. Table 18.2 also reveals the number of years these sup￾plies are projected to last if usage proceeds at the present rate and no new sources are discovered. As probably expected, iron, oil, and coal top the list by far with respect to world production. Some forecasters predict an exponential growth of usage for some materials. This would deplete the resources much faster than the above-assumed constant level of consumption. A spe￾cific time interval, tD, may be defined, during which future con￾sumption is predicted to have doubled, that is, tD
69/r, where 376 18 • Economic and Environmental Considerations 18.3 • World Reserves TABLE 18.2. Annual world production and estimated world reserves of materials (data in 106 metric tons except for crude oil, which is given in 109 barrels (bbl), whereas 1 bbl of oil is 0.159 m3 or 0.18 tons). The production data are for 2000 and the world reserves from 2001/02. World World Years’ Materials production reserve base supply Iron ore 620 160,000a 258 Copper 13.0 650 50 Aluminum 30.1 6,600b 219 Lead 6.0 130 22 Zinc 8.8 450 51 Tin 0.3 11 37 Nickel 0.9 140 155 Silicon 4.5 Essentially unlimited Potash 25.0 17,000 680 Phosphate 41.4 37,000 894 Crude oil 27.9 1,047.5 38 Coal 4,343 984,453 227 aWorld iron ore reserve base: 330,000 106 tons. Two tons of iron ore yield approximately one ton of iron. Note: Scrap iron is not included. bBauxite world reserve: 33,000 106 tons; Bauxite yields 1 ton of Al from 4 to 6 tons of ore. Sources: USBM, Mineral Commodity Summaries 2002, “World Oil,” Au￾gust 2002, for crude oil, and “1999 Survey of Energy Resources,” World Energy Council for coal