Weekly journal-miner., 1909-01-13
WARREN DISTRICT
 WORLDS COPPER TREASURY

! and Inc llrgc~i m NTllnhas W"uc ] blister copper production of abont l lOOOo.00O pounds, as compared win about i2l,o0OO0o pounds in 1906. The Iouiput would have been larger had it
 mol been for the reduced scale of opcr. iation. during the last three months of
 thc year. AS in previous years, tho
 production was derived almost entire. | ly from the Copper Queen, Calumet Arizona, Superior & Pittsburg and
 shattuck Arizona mines.
 The primary ore of this district,
 which consists of pyrite and chalco
 pyritc, and possibly bornitc, replaces
 limestone near an intrusive body of
 granite porphyry. and is now common ly regarded as the result of n modified
 sort of contact mctamorphism. The
 copper of these primary ores has been
 in part concentrated by the process
 known as secondary enrichment in lto workable ore bodies of varying size
 and irregular shape
 The tops of most of the Bisbee ore bodies lie at some distance below the
 surface and the ores are in many places undcrain by practically barren
 limestone instead of primary ore. In other words. secondary enricdmcnt has
 in some places extended to the very
 bottom of the ore obdics. Oxidation,
 also. has extended Co unusual depth.
 The ores consist mainly of carbon.
 atcs. oxides, chalcocitc, chalcopyrite
 and pyrite, all being in places more or
 less intimately mixed. Native copper
 Is present also in many localities, and
 in some stopcs has been very abun'
 dant. AS nearly as can be learned be
 tween 35 and 90 per cent of the cop
 per mined in 1907 was contained in
 the sulphidcs, chiefly chalcocitc, and
 practically the whole of the remainder
 wns carried by the oxidized minerals. The percentage of sulphide ore mined
 is increasing.
 If the total production since the dis. E cov,ry of the district is taken in ac. Il count Bisbee is undoubtedly the rich. est of the great copper camps of the U country. The ore mined to date is es. tmated to have yielded s per cent z copper. The yield in recent years has been somewhat below the average, and '' fell somewhat lower in 1907. The " Calumet & Arizona ore. as stated in the annual report of the company ' yielded 5.s5 per cent in 1907, eompar ' ed with 1.D5 per cent in l906, based u on the tonnage as mined. The cores ' bonding yield from the Superior S
 Pittsburg ore was 3.G9 per cent in l00i
 and 4.099 per cent in 1906. All tho
 ore mined in the district is ricl $ enough to smelt. and no concentration
 is practiced. The ores contain rathe
 low values in gold and silver. In 190; r. the yield of gold and silver per ton o' r. copper was sl3.7i for the Calumet S re Arizona company, and s6.90 for th' S. Superior & Pttsburg company.
 n' The locus of the principal known orr D. bodies has been shown to be n grea To flat lying shoot of variable thickness
 and as yet undetermined extent, pitch Ie ing gently toward the southeast ap s. proximately with the bedding of thu ie limestones. Probably the most i'm K portnnt feature of the year was ih' 10 development on the lower levels O ie Calumet X Arizona workings of bodie ,t of pyrites, ehalcopyrte and bornit' a. ore, little enriched and carrying goo' |. copper values. This discovery strength
 ems tho possibility of the existence o ,r other important ore horizons underly k. ing the one already developed and n n. such depth as to be mainly or who'll, e below the zone of secondary enrich DO mcnt.
 te The ore bodies worked at presen c. lie mostly between the depths of 40 t. and HOO feet, the ore being deepe d. toward the southeast. The known or V bodies near the surface are practical, s exhausted. All development is carrie' is on by means of vertical shafts, none Q is which has as yet been sunk far bcloy )f the horizon of known ore bodies. Wa c, ter has given considerable trouble Il C. the sinking of the deep shafts in tn
 southern part of the camp, but whe s- block of ground is once drained onI IT.. light pumping Is required. The squar ne fset and filling system is mainly em
 ployed, and the high price of mmbe n constitutes an important part of th 's. cost of mining, Underground haulag tn is now being done in part by electric V. ity. Wages are also nigh, but Nan' ga portation charges are not excessive te owing to the service by the Fl Paso re Southwestern railroad, line control 2. l nl L. nL al,.- n..dua G Lx. gL..r.