496 



The National Geographic Magazine 



Mrs Alexander Gralia 



Indian Types 



be of no value often can be worked with 

 considerable profit. There are vast 

 quantities of refuse and tailings from 

 old mines and primitive reduction works 

 which contain large values, and some of 

 these are being worked over with most 

 satisfactory results. Often the fairly 

 good ore was discarded in the early days, 

 when only the high-grade material was 

 worth freighting. On the old dumps at 

 one mine in San Luis Potosi there were 

 over 300,000 tons of mine refuse con- 

 taining much metal. In Guadalajara 

 tailings have been used for asphalt pav- 

 ing which recently were found to run $15 

 a ton in gold and silver. Electricity, 

 generated mostly by water power, is now 

 being utilized at some mining districts 

 and proves to be a great source of econ- 

 omy. 



It is estimated that about $80,000,000 



of United States capital are invested for 

 purchase and equipment of Mexican 

 mines and large amounts have also been 

 invested from other countries. The 

 present high price of the various metals 

 has given impetus to Mexican mining, 

 while the large amount of capital avail- 

 able in the present high tide of prosper- 

 ity in the United States has been an im- 

 portant factor. The known mineral dis- 

 tricts in Mexico are numerous and ex- 

 tensive and many portions are by no 

 means fully developed. There are numer- 

 ous regions also in which the mineral re- 

 sources may prove important which 

 have not as yet been explored by skilled 

 prospectors. 



The following table, taken from the 

 Mining World for January 26, 1907, 

 gives the principal metal production of 

 Mexico for the past 27 years : 



