Checking the Waste: A Study in Conservation

by Mary Huston Gregory

[CHAPTER VII]

IRON

We have already stated the importance of iron in our modern life. It can not be overestimated. All the many articles of iron and steel, our tools, our machinery, our vehicles, our bridges, our steel buildings, and a thousand and one other things are dependent on our iron supply.

Of all the elements that make up the earth's surface only three are more plentiful than iron, so that we might think that we should always have an abundant supply of it; but when it occurs in small quantities, as is usually the case, it can not of course be profitably mined. It is only when enough of it is found together to permit it to be mined to advantage that it is called iron ore.

Iron ore is found in only twenty-nine states of the Union, and eighty per cent. of the present production is in two states, Minnesota and Michigan. We can see that iron is very unevenly distributed, and it is on a few regions that we must depend for all the future.

Before we can calculate how much iron we have we must understand that it is not found in pure form, but mixed with various other substances: clay, shale, slate, quartz, sulphur, phosphorus, etc. These must all be removed, some by washing, but most of them by roasting, or "smelting," in blast furnaces, after which it is called pig iron. This of course requires large quantities of fuel.

It is these things and also the position of the ore that must be taken into consideration in estimating the amount of iron in the country. If ore yields a large per cent. of iron in smelting, with a small amount of waste, it is, of course, far more valuable than if the amount of iron in every ton of material taken from the ground is small.

In all minerals, the relation of supply to price is marked. The cost of labor and of power is exactly the same whether ore yields fifty-five tons of pure iron to the hundred, or whether it yields only thirty tons, but the price received is little more than half.

So if the price is low, it may cost more to mine and smelt the one hundred tons of earth than will be paid for the thirty tons of iron that the low-grade ore would yield. So the lands that produce only thirty tons to the hundred will never be mined till the price of iron is so high that it is above the cost of producing—that is, till it can be worked at a profit.

The Lake Superior iron found in Minnesota is usually more than fifty-five per cent. pure iron. That is, if a hundred tons of earth be mined, more than fifty-five tons of pure iron would be obtained from it. This is the highest grade of ore. Some ore is mined that yields only forty tons or less. There are vast quantities, billions of tons, of iron ore in the United States, that would yield less than thirty tons of iron to the hundred. These low-grade ores and the ones known to lie so deep in the earth that the cost of mining them is more than the finished products of iron, are classed as "not available," that is, they can never be profitably mined under present conditions. But we must remember that as the higher grade ores are exhausted it will become necessary to use the lower grades, and that prices will steadily advance as a result.