NOTES ON THE LEAD AND ZINC DEPOSITS OF 



THE MISSISSIPPI VALLEY AND THE 



ORIGIN OF THE ORES. 



The recent closing down of the silver mines of Colorado and 

 other Western states means not only a lessening of the silver pro- 

 duction of the country, but also the shutting off of its greatest 

 source of lead supply. During the past few years over two-thirds 

 of the total yield of domestic lead has been from the argentiferous 

 lead ores of Colorado, Utah, Idaho, Montana and Nevada. Unless 

 operations are resumed in the West, the demand must consequently 

 soon be concentrated upon the deposits of non-argentiferous 

 lead in the Mississippi Valley, which have been in the past the 

 sole important producers. A rise in the price of lead is to be 

 expected as a result, which, in turn, will lead to increase in exploit- 

 ation and development. 



The question naturally arises, therefore, to what extent are 

 these Mississippi Valley deposits to be depended upon for future 

 supply. They have been large and almost constant producers 

 in the past; will they continue to be such in the future? The 

 history of their development, which is in many respects remark- 

 able, lends color to the hope that such will be the case, especially 

 in Missouri. Lead mining was begun in that state as much as 

 170 years ago, and has continued almost uninterruptedly since. 

 Indeed, the first deposit worked, that of Mine La Motte, has up 

 to this year supplied large quantities of ore, the total value of its 

 product to date being in the neighborhood of $8,000,000. The 

 various bodies of ore have shown signs of exhaustion from time 

 to time, and the industry in the state has waned. About the year 

 1854 the condition was such that even so competent a judge as 

 Prof. J. D. Whitney 1 ventured the prediction that the supply was 

 nearly exhausted, and that the lead mining of Missouri was a 

 thing of the past. But ever after such depression, deeper exca- 

 vations have developed new bodies of untouched ores, wider explo- 



1 Metallic wealth of the United States, p. 419. 



612 



