Page 666 - Environment: The Science Behind the Stories

For instance, geologists in 2013 calculated that the
world’s known reserves of tantalum will last about 200 more Nickel Economically recoverable
years at today’s rate of consumption. If demand for tantalum Iron from ore Technically recoverable
increases, it could run out faster. And if everyone in the world
began consuming tantalum at the rate of U.S. citizens, then Molybdenum
it would last for only 15 years! Most pressing may be dwin- Cobalt
dling supplies of indium. This obscure metal, which is used Zinc
for LCD screens, might last only another 30 years. Because of
these supply concerns and price volatility, industries now are Copper
working hard to develop ways of substituting other materials Titanium
for indium. A lack of indium and gallium would threaten the
production of high-efficiency cells for solar power. Platinum Lead
is dwindling too, and if it became unavailable, it would be 0 50 100 150 200 250 300 350 400
harder to develop fuel cells for vehicles. However, platinum’s Years left available, at present rates of consumption
high market price encourages recycling, which may keep it
available, albeit as an expensive metal. Figure 23.12 Minerals are nonrenewable resources, so sup-
Figure 23.12 shows estimated years remaining for several plies of metals are limited. Shown in red are the numbers of
selected minerals at today’s consumption rates. Note that each remaining years that certain metals are estimated to be economically
bar in the figure consists of two parts. The left (red) portion recoverable at current prices. The entire lengths of the bars (red plus
of the bar shows the number of years researchers calculate orange) show how long certain metals are estimated to be available
that we will have the mineral available under today’s eco- using current technology on all known deposits, whether economically
nomic conditions. As minerals become scarcer, demand for recoverable or not. Data are for 2012, from U.S. Geological Survey, 2013. Mineral
them increases and price rises. Higher market prices make it commodity summaries 2013. USGS, Washington, D.C.
more profitable for companies to mine the resource, so they Which metal has the highest proportion of its technically
become willing to spend more to reach further deposits that recoverable reserves that are currently economically
were not economically worthwhile originally. Thus the entire recoverable? Approximately what percentage is economically
length of each bar in Figure 23.12 shows the number of years recoverable? Which metal has the smallest proportion of its
researchers calculate that we will have the mineral available technically recoverable reserves that are currently economically
recoverable and what is this value?
in total, as prices rise. These two categories used by the U.S.
Geological Survey (USGS) are similar to the way the USGS
classifies fossil fuel deposits as being either “economically
recoverable” or “technically recoverable” (pp. 545, 549).
to reach difficult deposits, rising prices also may favor the
development of enhanced mining technologies that can reach
Several factors affect how long mineral more minerals at less expense. If more powerful technologies
deposits may last are developed, then these may increase the amounts of miner-
als that are technically feasible for us to mine.
Calculating how long a given mineral resource will be avail-
able to us, as shown by the data in Figure 23.12, is beset by a Changing social and technological dynamics
great deal of uncertainty. There are several major reasons why New societal developments and new technologies in the market-
such estimates may increase or decrease over time. place can modify demand for minerals in unpredictable ways.
Just as cell phones and computer chips boosted demand for tan-
Discovery of new reserves As we discover new talum, fiber-optic cables decreased demand for copper as they
deposits of a mineral, the known reserves—and thus the years replaced copper wiring in communications applications. Today
this mineral is available to us—increase. For this reason, some lithium–ion batteries are replacing nickel–cadmium batteries
previously predicted shortages have not come to pass, and we in many devices. Synthetically produced diamonds are driving
may have access to these minerals for longer than currently down prices of natural diamonds and extending their availabil-
estimated. As one recent example, in 2010 geologists associ- ity. Additionally, health concerns sometimes motivate change:
ated with the U.S. military discovered that Afghanistan holds We have replaced toxic substances such as lead and mercury
immense mineral riches that were previously unknown. The with safer materials in many applications, for example. CHAPTER 23 • Min ERA ls A nd Mining
newly discovered reserves of iron, copper, niobium, lithium,
and many other metals are estimated to be worth over $1 Changing consumption patterns Changes in the
trillion—enough to realign the entire Afghan economy around rates and patterns of consumption also alter the speed with
mining. (Note, however, that such riches are not guaranteed which we exploit mineral resources. For instance, economic
to make Afghanistan a wealthy nation; history teaches us that recession depressed demand and led to a decrease in produc-
regions rich in nonrenewable resources, such as Congo and tion and consumption of most minerals from 2007 to 2009
Appalachia, have often been unable to prosper from them.) after rising for long stretches. However, over the long term,
demand has been rising. This is especially true today as China,
New extraction technologies Just as rising prices of India, and other major industrializing nations rapidly increase
scarce minerals encourage companies to expend more effort their consumption. 665

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