Mohave County miner., 1909-02-20
Mineral Wealth as Affected by Tim
 Der Product.

Few persons not directly interested in mining realize the extent to which timber is used in this very important industry" said a government expert in preservation of mine timber re- gently. "The average man has only a vague understanding of the import ance of the part that timber plays in the mining industry, and seldom thinks of the enormous quantities required each year to prevent the caving of overhanging ground and to keep clear the main working passages of mines.
 "There are two general classes such timbers," he continued, ''the first is used in bracing the 'stopes. as they are called, where the ore is being talk en out. As the ore is mined the sur rounding rock is held n place by bracing it with heavy timb -,s, framed into rectangular sets When ore di- rectly above the first set is removed, second set is built in on top. and so on. I ore is exhausted and the active mining transferred to another vein or ore body.
 After a time these timbers decay to point where the pressure of the rock walls crushes them, and cave in occurS. This causes na damage if, as I have said. the mining work has been finished: but tt sometimes hap pens that decay has weakened the tim bers to such an extent that the cave-in occurs prematurely, and then lives are sacrificed. in such cases the remaining ore is also loss, for when the ground has once commenced to move or work, as the miners call il, it is almost i'm possible to clean it out and back the rock so that the remaining ore may be obtained.
 But of still greater importance is the second-class of timbers used in the main working openings, tunnels, shafts, etc., which are to be maintained for as long time as possible. Timbers for this service are chosen not only for their strength and firmness but also for their ability to resist decay.
 ''In nine cases out of ten when tim bers are crushed, the indirect cause is decay, produced by low forms of plant life. The dwindling of our timber supply has driven consumers of wood all over the country to study decay and its prevention, and it is safe to say that in the very near future we shall see many more mines putting in small plants for the treatment of their tim bers, after the pattern of the plants that have been designed and installed for this purpose by the United States forest service. By treating the per manent timbers with some one of the various praservations, they must be made to resist decay almost indefi- nitely. The additional cost Is slight.
 ''The wo k of treating mine timbers is considered of such importance that one group of men in the forest service gives its entire attention to this sub- ject. Investigative work carried on by this branch of the service since it was organized has demonstrated that treating with an efficient p"eservative will prolong the life Of timber indef- initely in places where before it was subject to rapid decay, and the in terest shown by the large consumers of timber and their eagerness to SUD- ply the information that has been ob- tained to their own particular prob lens has been widespread and indi- cative of the benefits of wood preser- vation.'