Bisbee daily review., 1904-03-05


 prospecting to nearly horizontal planes. There is certainly reascn- able hope of finding ore bodies in the Martin and Abrigo limestones beneath the masses that have been so profit ably worked in the overlying carbon ferrous beds. The occurrence of small punches of ore in the Abrigo limestone at the Whitehall and Wade Hampton claims shows that ore de- position may take place in these lower beds. It may be that, owing to their greater depth, such ore bodies, if dis covered. will be found to consist of low-grade cupriferous pyrite. un- enriched by the generally descending solutions that have contributed so largely to the value of the known masses. This, however, is a point that prospecting alone can determine. It would seem that near the Dividend fault the conditions are favorable for the continuance of enriching pro cesses to depths greater than those
 
 ground workings.
 But more than this, it may be point ed out that less than half of the semi circular mineralized zone about the porphyry mass of Sacramento hill has been explored a. all. Ore was first discovered at the surface on Queen hill at the northwest enc of the zone. From this discovery, developments have been pushed by underground ex- ploration to the south, often with little or no surface indication of ore. There still remains, however, an extensive area of unknown but promising ground lying just south of Sacramento hill and extending eastward toward the southeastern continuation of the Divi- dend fault, which is here concealed by the Glance conglomerate This is the eastern half of the semicircular miner alized girdle about the intrusive mass of porphyry. While structurally the beds south of Sacramento hill form less favorable nook for the deposi- tion and concentration of ores than that enclosed between the Czar and Dividend faults and the northern con tact of the rorphyry, yet their attitude with reference to the intrusive stock and to the probable continuation of the Dividend fault down Mule gulch is distinctly favorable to mineraliza- uon. The developments in the Spray and the Calumet & Arizona mines have shown that profitable ore bodies are by no means confined to the struc- tural pocket in the vicinity of the Czar and Holbrook shafts. There is no known reason why they should not yet be found skirting the southern contact of the porphyry for some dis tance eastward towards Mule gulch 1t is thus probable that the ore zone. if present, also turns south along the contact of the limestones with the DOT phyry, and does not extend eastward under Mule gulch itself
 It is true that the easterly dip of the bees south of the porphyry stock carries the escobrosa limestone to a much greater depth near Mule gulch than it has in any of the present work ings. It is probable that this depth, a short distance east of the Gardner shaft, may be so great as to preclude the occurrence within the Escabrosa limestone of any but the original un- enriched pyritic ere, which may or may not be workable But judging from surface indications, there has been considerable naturalization of the Naco limestone south of Sacra- mento hill, and there is nothing i'm probable in the occurrence of high grade ores in this limestone at stati- graphically higher horizons than those in which ore bodies have hitherto been found. The exploration of this ground calls for no greater outlay or boldness than is already displayed in other parts of the district with less assured hope of reward.
 The outlook for finding profitable ore bodies within the main porphyry stock of Sacramento hill is not re- garded as particularly promising. As the dump of the Copper King shaft shows, this rock may be very heavily fmpregnated with pyrite. But the naturalization seems to tend more to abundant dissemination than to the formation of solid sulphide masses Even if the latter occur, it is doubtful whether they would be found sufi- ciently cupriferous to constitute ore. Moreover, the chemical and physical character of the porphyry render it very much less favorable than the limestones to the deep oxidization and secondary concentration that has played so important part in the gen. esis of the known ore bodies. Very little exploration of the porphyry has been made, however, and work in this direction cannot be condemned as al. together vain
 In conclusion, it may be said that Bisbee is less likely to suffer from a lack of ore than from a too rapid ex haustiOn of those hiph-grade oxidizad