FORESTRY AND IRRIGATION 



June 



In considering the material available to 

 the United States we should take account 

 of the supplies in adjacent countries. Mex- 

 ico is as yet very imperfectly explored. In 

 Canada there are vast areas of wholly un- 

 explored territory. In Cuba, examinations 

 made by Spencer show that the known re- 

 serves of iron ore of fair metallic content 

 are very large, and some of the more ex- 

 tensive of these deposits are already con- 

 trolled by United States capital. Of the 

 South American iron ore resources we are 

 as yet very imperfectly informed. 



While the additions to the known re- 

 serves of iron ore available to the United 

 States, which are to be made by discoveries 

 i the western United States, in Canada, 

 in Mexico, in Cuba, ar ' in South America, 

 are uncertain, it is hardly possible that the 

 amount will not be very important ; but as 

 vet there is no reason to suppose that dis- 

 coveries in any of these countries, with the 

 oossible exception of Cuba, will reveal iron 

 ore deposits comparable in importance to 

 the Lake Superior and the Southern Ap- 

 palachian districts. 



From the foregoing facts it appears prob- 

 able that for some years to come iron ore 

 available in the United States will continue 

 to be discovered more rapidly than it is ex- 

 ploited, and consequently the total known 

 reserves will increase rather than decrease. 

 Hence the crest for known iron ore re- 

 serves of high grade may therefore be some 

 years in the future. 



While, therefore, it is safe to say that the 

 available high grade iron ore will be ade- 

 quate for possibly a century, even if the 

 rate of production further greatly increases, 

 it is to be remembered that as the percent- 

 age of iron ore goes down a larger amount 

 of coal is required to obtain a ton of metal- 

 lic iron, and, therefore, in proportion as our 

 rich ores are exhausted, the draft will be- 

 come steadily heavier upon the most im- 

 portant of the underground resources 

 fuel. 



Turning now to another metal, copper, so 

 far as I know there has been no systematic 

 attempt to estimate the copper reserves, but 

 it is safe to say that the known reserves of 

 high grade copper are at the present time 

 very much less than they were some years 

 ago. It is true that the copper product of 

 the United States, as well as that of the 

 world, has steadily increased for many 

 years until 1906, when maxima of 410,000 

 long tons for the United States and 705,000 

 long tons for the world were reached. The 

 vear 1907 shows a falling off from these 

 figures of between 9,000 and 10,000 tons for 

 the United States and between 7,000 and 

 8,000 for the world. Whether this check is 

 temporary is uncertain, but it suggests that 

 f we have not already reached the crest of 

 oroduction for copper we are nearing it. 

 Indeed the rapid annual increase in the out- 

 put of copper for the past dozen years has 

 only been accomplished by the exploitation 



of increasingly lower grade ores. At the 

 present time it is clear that the crest of 

 known reserves of high grade copper ore 

 has been passed. However, as in the case 

 of iron, the extent of the low grade mate- 

 rials is very imperfectly known, and in the 

 future for a time the output may remain 

 as great as in the past, provided sufficiently 

 low grade ores be worked. But with refer- 

 ence to copper, as with reference to iron, 

 it is to be remembered that the lower ihe 

 grade of ore the more it costs to produce a 

 pound of metal, and therefore that, as the 

 grade of the ore decreases, the price of the 

 copper must rise. Those who are familiar 

 with the situation know that in any of the 

 great camps, upon the average, it costs more 

 to make a pound of copper than it did a 

 few years ago. 



For lead and zinc, gold and silver, it is 

 not possible to make statements even as 

 definite as those concerning copper. These 

 metals are usually developed in the mines 

 only to a limited degree in advance of (heir 

 exploitation. Therefore there never have 

 been at any one time in many years reserves 

 of the ores of lead and zinc, of gold and 

 silver in sight. There are no great known 

 reserves for those metals in the sense that 

 reserves are known for ?">" ore. However, 

 exploration and exploitation have gone on 

 together with the result that there has been 

 a steadily increasing output of these metals 

 both for the United States and for the 

 world. Indeed the increase for the last 

 twenty-five years has been remarkable. The 

 percentages of increase for 1907, as com- 

 pared with 1883, twenty-five years previous- 

 ly, are as follows : 



For lead, 150 per cent; for zinc, 537 per 

 cent } for gold, 62.9 per cent ; for silver, 

 21.8 per cent. 



Apparently the maximum output for 

 none of these metals has been reached, with 

 the exception of silver, which with the 

 United States has been nearly horizontal 

 for about fifteen years, and for the world 

 has somewhat declined for the last half 

 dozen years, as compared with the previous 

 period of the same length. How long we 

 may expect an increase in the output of 

 lead, zinc and gold is uncertain, but, as in 

 the case of copper, it may be said that the 

 maintaining of an increasing output for the 

 United States and for ..^ world has only 

 been possible by utilization of lower grade 

 ores. 



It is a very conservative statement to 

 make that during the last half century from 

 the earth there have been taken more of 

 our metallic wealth than during all the 

 previous history of its exploitation. For 

 some of the metals we may illustrate the 

 marvelous increase since 1850: 



From 1810 to 1853 the amount of iron ore 

 exploited in the United States is estimated 

 at 4,500,000 long tons; from 1854 to 1907, 

 more than 640,000,000 long tons. The pig 

 iron product of the world from 1500 to 



