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Show APPENDIX NK. 1259- t i m e assert its supremacy and come back to its accustomed level. It also flooded a neighboring miue, the Hale and Norcross, which has also been at work pumpiug ever s i n c e , and thus these two mines are uuaile to proceed with any protitable work or w o r k of exploration, while there is still an enormous drain on the pockets of the stockh o l d e r s for the expenses of pumping and the other expenses inoideutal to the flooding o f t h e mine. Heretofore all the large bodies of water struck in the mines have been at a higher l e v e l and have been rapidly pumped out and have not returned in large quantity. a n d this has strengthened the idea that the water occurs in pockets or reservoirs, ana t h a t when these are drained off it will cause no further trouble. This water in the S a v a g e Mine, however, seems to tell a different story. It is very hot, about 154° t o 160° FM and in all probability comes from the same heated source as the water w h i c h wellB up from the Hot Springs in the valley below at Steamboat. As t h e s e springs are constant, it is altogether probable that the water which enters t h e Savage is also oonstaut or nearly so, aud that it connects with the heated water w h i c h permeates in a more or less connected manner all the fissures and subterran e a n channels below. In one mine which I visited, the Imperial and Empire, I descended to a depth of 2,135 feet and found the temperature to range from 110° to 115° F. There was at least one stream of hot water coming into the mine, which, on testing, I f o u n d to be 154° F. In other parts of the world, where mines have been sunk very d e e p , it has been found that on an average the temperature increases 1° F. for every 50 t o 60 feet of descent from the depth at which the temperature first becomes cons t a n t , which is about 100 feet below the surface ; this constant temperature beiug, as near as it can be determined, 47° F. Assuming 55 feet to be the equivalent in descent o f 1° F., we have in the Imperial and Empire 2135ft-- 100ft- , Mmn„ nAn„ ^ + 47° F. = 8 4 * F. or, according to this rule, the temperature at the depth of 2,135 feet should be 84° * Instead of this, and in spite of the fact that great quantities of cold air are pumped i n , it reaches in places as high as 110° and 115° F. Undoubtedly the cause of this great heat is the inpouring and circulating hot water, which comes in quite large quantities, the amount pumped from the mine being about 6 miner's inches. There are two hypotheses to account for this heated water: one being that it is heated by the chemical action going on iu some mineral or other vein through which it passes. It is asserted and believed by many that as the hot Savage water came in from the east, when the exploration shall be pushed on eastward a vein of the same general character as the Comstock will be struck,. the chemical action in which is the cause of the heating of the water. The supposition that such a vein exists is no doubt very materially strengthened by. the existence of this hot- water stream, but it can scarcely be considered as proof. The other hypothesis, and to my mind the more plausible one, is that the water comes up from the heated interior of the earth. The water which falls to the earth in the form of rain and snow, and which penetrates below the surface, exists in many conditions throughout the crust of the earth, sometimes occurring in pockets, which are filled slowly by infiltration or narrow inlets, but which on being struck empty themselves quickly and are no further cause of trouble ; sometimes in large fissures through which the water is continually circulating, and which, on being struck, give an almost unio-termitted stream for months and years. Such a fissure exists in the Sutro Tunnel, and i t is observed that when such a fissure- vein of water is encountered, it diminishes its yield for some time until it reaches a point when it becomes constant. This may be accounted for on the supposition of connecting pockets, which are gradually drained off. This water finally finds its way down to the heated interior of the earth and is there converted into steam, which in its efforts to rise forces back the water, and thus an equilibrium is attained, the water and fire making the steam and the strain holding the water in suspension. The steam in its efforts to escape percolates up through the water and heats it, aod this in turn ' eats the surrounding rocks, and possibly is the cause, not the effect, of the chemical action which is coutiuually going on in the mineral veius. When this hot water and steam can find a direct outlet to th* surface, they appear in the form of hot springs and geysers; when they cannot, they give up their heat to the rocks aud the down- pouring cold surface- water. There is no doubt that the mine in which this water occurs is debarred from further downward progress if the water remains constant, unless some new method of drainage is found and adopted; for if it were possible to keep it down by a great addition to the pumpiug force, it would cost so much that the mine would be totally unprofitable. What this new method of drainage will be remains to be seeu. Possibly it may be the Sutro Tunnel. The tunnel has now reached a length of between 15,000 and 16,000 feet, and is being { rasbed forward with marvelous celerity, making on an average 300 feet per month in ength. It will, when it reaches its entire length, ( which it will probably do in the spring of 1879,) strike the Comstock, near the Savage, at a depth below the surface of about 1,900 feet, and then the water which may impede the working of the mine will have to be pumped a vertical distance of 1,900 feet less than now. It is altogether |
