Bisbee daily review., 1918-01-20


 northeast has had the effect of throw ing the old depressed area 10 the south of the dividend fault up. and depress- ing the country to the north. As a consequence, the area to the south being higher, was worn away first. and the area to the north last The later cretaceOus sediments Outcrop therefore almost entirely to the north of the Dividend fault with only rem nants of glance cOnglOmerate to the south.
 From this it is seen that the original primary ores have been subjected to two ages of erosion and oxidation by ground waters. one just atfer being put in and up to the time when the glance cOnglOmerafe was deposited, and the second from the end of ere taceOus to now. Of these two ages the one having the most effect on the ores was the first The reason for this is that by the time the wearing away had reached the ore zone on the north the ground water must have been very strong with acid, and was therefore very powerful to alter the ores to the south
 Referring again to Fig 9. the posi- tiOn of the ore bodies is shown by the shaded areas. As you will notice the biggest ore zone is right around the Sacramento Hill stock Besides this zone there are OffshOOts along the Car fault. Silver Bear fault, and Sac ramentO and Shattuck dikes.
 D.r =r- s-- .. west section of the area taken through the ore zone, looking northeast. In this section all the ore on each side of the section is projected on the plane of the section As you see from this. the ore has a pretty regular dip from the west to the east This dip is the same as the dip of the sediments. and is the sane as the final tilting mentioned as taking place when the area was last lifted up above sea levei During the first erosion period before the glance cOnglOmerate the ores were probably horizontal. This ex- plains why the ore bodies of the Sac ramento 16O0 feet below the surface are just as highly oxidized as those ID the Car mine only 300 feet below.
 When we speak of alteration of rock we have to divide it into two kinds; First alteration by the hot vapOrs coming with and just after the porphyry; and second, alteration by cold ground waters from the surface. The first kind We call primary and the second. secondary
 In this camp. the primary alteration has changed both the HmestOnes and the porphyry Where the GmestOnss are pure. the alteration is not very strong, and we get beds of white marble right next to beds replaced by pyrite or ore. When the limestone is impure, like the Martin and AbrigO hmestOnes. they are completely al tered to quartz, pyrite and greenish grey sericite. Sometimes instead of serieite we get chlOrite. and serpen- tine. dark green to black soft min erals.
 The pOrphyry is usually highly al tered Instead of the original birds eye pOrphyry. we get a fine grained mass Of greenIsh grey sericite and quartz with pyrite grains and veins The only way to tell it from the alter ei limestone is the absence of bed ding. and occasional remains of quartz crystals
 The first mineral to be deposited by the hot TapOrs was SeTicite. fol- lowed by quartz Then came pyrite. and last of all the copper suIphiGes. and bornife. Secondary by cold waters from the sur face. has quite a different effect This cold water contains dissolved air which Oxidizes anything it comes in contact with. especially sulphideS. When it oXidizeS a sulphide of copper or iron. the air combines with the salphide to form sulPhurie acid This acid is the thing that does the leach ing and altering of the originally al tered pOrphyry and limestOnes to pro duce lmOnite soft kaOlin or mud. etc This is the reason that it is only In the oxide and enriched sulphide ore bodies that heavy ground is met wItA, while in primary ore. the walls may 5e just as highly altered by primary ore solutions. but have not been touch ed by sulphuric acid surface waters.
 will end this talk by giving you a list of the ores of the district. and sill divide them into Primary, Enrich ed and OxidiZed ores.
 The primary ores consist of pyriIe lsulphide or irOnl. chalcopy-ite (sut- phide of iron and cOpDerl and bOTnite ,sulphide of iron and copper. With primary ores We get as sangue min erals, quartz, sericite. chOlrite and ser penIine-
 Enriched ores consist of chalcOcite or copper glance (saIphide of copper with some pyTite isulphide of from. The gangUe minerals are quartz. kaO- lin l-nUdb. limOnite toVide of irOnl.
 OXidized ores consist of cuprite t0x- ide of copper. TenOrite Of copper pitch ialsO an oxide of copper. nal achite and szurite tcarbOnates Of cop perl and native copper. The gsngue minerals are quartz. limOnite. kaolin and manganese oxide
 FINANCIAL ARRANGEMENT.