those rich deposits was a fortunate happenstance, and

technology will be faced with a more difficult task in

the future.

 In the first place, shortages of rich domestic

ores in the United States have occurred only recently.

Therefore, stable prices and decreasing labor and

capital costs relative to output were consistent with

deteriorating concentrations, even in the face of

increasing demand, so long as the rate of technical

advance or scale economies exercised a stronger influence

on costs and prices than did declining ore yields. The

initial minerals position of the United States was one of

super abundance, and with resources extensive enough,

costs might decline or remain constant for a long time,

but not necessarily forever.

 Second, labor and capital costs are not the only

costs involved. Increased power, for example, requires

increased fuel consumption which in turn can mean

higher costs of production30 and increases in productivity

have required large increases in power. While only 5

horsepower were employed per production worker in 1902

in all metal mining, 98 horsepower were employed per

production worker in 1963. Horsepower employed per


 30Provided that fuel prices do not decrease
or that efficiency of fuel use does not increase by
enough to offset increased energy requirements.