MINE TIMBERS 331 



Pennsylvania, with its important coal mines, both anthracite and 

 bituminous, is the most important state in the consumption of lumber 

 and timbers. This state probably purchases more than 50 per cent of 

 the total value of mine timbers used in the entire country. 



KINDS AND AMOUNT OF WOODS USED 



The character of wood used in American mines is not highly spe- 

 cialized. Generally speaking, almost any kind of wood which is suffi- 

 ciently strong will meet the requirements. Altogether, durability is the 

 most important single requirement and where woods of great durability 

 are not available, woods of a more or less perishable nature can be treated 

 to increase their life in service in the mines. Furthermore, in many of 

 the mines of this country , the use of wood as a means of support and for 

 mine ties, mine rails, etc., is only temporary, and after a period of service 

 of from two to four years, they are either left to decay or removed and 

 placed in service in some other location. Where woods are to be in ser- 

 vice only two to four years, almost any species will serve the purpose, 

 because even our most perishable woods will last, generally, from three 

 to four years. 



The conditions found in most of our underground mines, however, 

 are exceedingly favorable to decay because of the damp condition of the 

 atmosphere and the relatively high temperatures involved. 



It has been determined that hardwoods constitute by far the most 

 important source of supply for mine timbers. Of the total cubic footage 

 of round timber, namely, 165,535,000 cu. ft., over 86,000,000 cu. ft. 

 were of hardwoods, 38,000,000 of softwoods, and the remainder amount- 

 ing to somewhat over 41,000,000 cu. ft. were not specified as to their 

 character. The preponderating use of hardwoods can be probably 

 attributed to the fact that the most important wood-using mines of the 

 country are located in hardwood regions. 



For the purpose of classifying the utilization of wood, all mines have 

 been divided into the following category, namely, bituminous, anthracite, 

 precious metal, iron, and miscellaneous mines. Most of the wood-using 

 mines of this country are found in the bituminous class and they are also 

 the most prominent in the use of timbers. All of the anthracite mines 

 are found in Pennsylvania and are also very important consumers of 

 both round and sawed timbers. The precious metal mines are located 

 principally in the West, in such states as Montana, California, Colorado, 

 and Arizona, where generally speaking, there is a fairly good supply of 



