These ores are sometimes associated with iron sulphide, but most of this class may be easily sorted. One class of ores occurs intermingled with the gangue containing about 15 per cent copper. This ore can be separated on any concentrating machine such as a jig, the resulting product being high grade. The ore shipped to Swansea has averaged over 33 per cent copper and 15 ounces silver per ton.
[Illustration: _LONGITUDINAL SECTION OF TIPTOP MINE LAVA BEDS DISTRICT SAN BERNARDINO CO._]
The Tiptop consists of two claims. The easterly one, the Kenton, has little or no development, though copper carbonates have been discovered on the ground. All of the workings of the Tiptop that are in copper ore, it should be remembered, are in the country rock on the foot wall side of the series of faults in which the silver ore occurs, and no drift or crosscut had been run into that zone below 80 feet from the surface. The face of the drift on the third level had exposed about 6 feet of good ore at the time of my examination. The drift at that point was 160 feet from the surface. It is not likely, should a crosscut be run under the silver ore shoot from the lower levels of the mine, that oxidized ore will be found at that level, but it will be interesting to know what sort of ore may be found there. Indications of copper on the surface are very slight. In a few places stains and thin seams of copper carbonates occur in the fracture joints of the country rock, but there is nothing to lead one to believe that ore lies beneath that will bear shipment to Europe and return a handsome profit to the owners of the mine, yet such is the case.
Less than a mile from the Tiptop, in a northwestern direction, is another property, the Gladstone, locally known as Halberg’s Gold Mine. It was located several years ago, and after some development was practically abandoned, but afterwards came into the hands of the present owners, who have developed the ground quite extensively, built a long tramway and ore bins, and established a camp.
Nothing was being done at the time of my visit. The mine is something of a curiosity geologically and mineralogically. The ore body, for there is only one of any consequence developed, occurs in the gray quartz porphyry common to the region. A fault has also occurred here, fracturing the country rock in a manner similar to that in the Tiptop, excepting that here there is but a single, simple fault. The ore body consists of a mass of crushed and broken country rock, portions of which still show distinctly the original porphyritic structure. Generally speaking, however, the original rock has undergone an extreme metamorphosis, resulting, in most cases, in more or less complete mineralogical and physical changes. The porphyry has, by gradual replacement, been changed to solid ore, or been silicified to a dense quartzose, sometimes jaspery, rock. Kaolinization of the feldspars has also taken place. As to the origin of these deposits there seems to be little reason to doubt that the ore was deposited by percolating waters, which derived their contents from the neighboring eruptive rocks. These solutions were carried into the fault plane, and reaching the great chamber or crushed mass, found conditions of a superior nature for the precipitation of the minerals they contained. In the pulverized or finely crushed portions the ore deposition has been most complete, entirely replacing the original rock, while in the brecciated portions the ore occurs as incrustations, filling the smaller interstices, but sometimes penetrating the rock fragments themselves.
