MINING, 
123 
APPLICATION OF GEOLOGICAL FACTS AND PRINCIPLES TO 
THE BUSINESS OF MINING. 
§ 86. Mining can be conducted safely only by employing the 
principles of geology as guides in conducting its labor. 
It is, therefore, a practical application of the observations of 
geologists which constitutes scientific mining. Mining, as 
commonly understood, is the extraction of ores from the beds 
and veins which they occupy in the earth. Its signification, 
however, may be extended so as to embrace the removal ot 
rock as well as ores from their beds; embracing, also, what is 
usually known as quarrying. 
^ Though mining is strictly the application of labor, as I have 
just defined, yet it has its theoretical part which is really of 
great importance, especially when facts form the foundation of 
those views. These constitute the philosophical part of the 
business. The skillful laborer will not disregard this part of 
the subject; it will even aid his mechanical labors in detaching 
the useful parts of the mine or of a quarry from their beds, and 
assist him in bringing to light the riches hid in the earth’s 
bosom. < 
Mining, in the comprehensive sense in which I design to use 
the term, may be treated of under the following heads: 
1. The theory of the formation of those depositories which 
contain the metals and ores. 
2. The structure of those depositories. 
3. The changes wdiich the mineral undergoes in depth. 
4. The best modes for extracting their metals and ores, 
including those which have been devised for raising blocks of 
rock from their beds. 
5. The expense attendant upon different kinds of work in 
mining and quarrying. 
6. The value of the products of mining. 
1. In the foregoing part of this treatise*I have already had 
occasion to speak of points which belong to, and which also 
