Show TUNNEL OR SHAFT there is a difference of opinion among mining men as to the best and most economical method of mine development some holding that operation by shaft sinking is preferable while others cling to the thory that the best results can be obtained by means of tunneling of course a great deal depends upon the location of different properties upon various existing conditions and more largely upon the amount of money on hand for development work but in experienced mining circles and where great results are looked and hoped for deep sinking is the popular method of mine exploitation and operation As a general thing unless the ore bodies lie in a blanket formation unless a tunnel is to be run to tap a known vein at a considerable sid erable vertical depth and unless it is expected that water will be encountered e in such quantity that it cannot be handled successfully cess fully excepting at a great and prohibitive expense a shaft should be sunk in the prosecution of mine development the tunnel of course is a poor mans proposition but this method of operation will certainly curtail the output of ore should pay rock be found in quantity for with the tunnel nothing can be done other unless it be that a than to f ollow follow the vein few upraises up raises can be made or a few dinzes sunk in which event a shaft might as well have been started in the first place in the operation of a mine by means of a shaft a greater area of good ground can be opened than is possible by means of a tunnel at every fifty feet in a shaft levels and drifts can be run out both ways on the vein or ledge and upraises up raises made from one level to the other and as work progressed it would be possible from time to time to put on more men which is a big consideration when an effort is being made to increase the tonn tonnage age of the output in tunnel operations this would be impossible as only a certain number of men and this extremely limited could be employed it is often impossible in many localities to gain any extensive depth when tunneling is in vogue so that this method is really the most expensive and the most unsatisfactory in the end there is a difference however in prospect development and mine operation A prospector is fully justified in running a tunnel in opening up his property for this work will not be extensive and not even permanent his endeavor is to show up the greatest pos isble amount of ore at trifling expense and with a small amount of labor A mining company however excepting in isolated cases will eventually find that it has made a mistake if it attempts to open up and operate its mine by means of tunnels only as a tunnel in most cases is only a makeshift and can be counted upon as being only a small factor when it comes to permanent workings and in providing an avenue from which great min mineral eral wealth is to be derived |