Arizona silver belt., 1904-06-16

ard to the principal mines of Globe
 dstuct
 The rebuilding of the Old Dominion
 .mslter Is the most ilnportante event ir
 ina recent history of Globe district
 With the adoption of mating and con.
 ,ertlng in the place of oxide smelling, il assures a greater economy in future ooerations, and furthermore, it should enlarge the scope Of the mining in mstry generally, inasmuch as the stores of Sulphide ore, heretofore neg rsrted, will become available for treat ment
 For number of years past Globe has been conspicuous as the only i'm. nrrlant camp in the southwest which pgzsd oxide ores exclusively and mrntd out it's product in the form of copper bars made by a single fusion. The United Verde mines began the treatment Of sulphites early in their career. At BiSbee the Copper Queen installed cOnyerters in 1894, and three yesrS later the Arizona and Detroit companies at Clifton were producing copper by the Bessemer process. The Old Dominion, however, continued making black cUpper from oxides down to laO2 d course that has naturally re- Slricted mining development through uut the district. With expensive fuel
 poor grade of coke costing Sl0 or more a ton and heavy loss of copper In the sIagS, due to the SiliciOuS char arter Of the ore it is evident, also, that this method of smelling was burdenod with great disadvantages.
 The Old Dominion is one of the rep rrsgntatiye mines of Arizona. It has a record during the twenty years of it's intermittent activity of over l20. 0O0, GOO pounds Of copper, and there is prom ISe of a long period ahead. The ore bodies that have been worked are both large and high grade. h the last two years Of operation, when treating OK ldes alone, the average tenor of the furnace charge was nearly x per cent copper, although the burden included t' per cent lean iron ore as ilux. There Is NtIlI a good supply of high grade ore in the mine and d much larger quan- i.ty Of material has been developed during the exploration of the rich OK 1eS that can Oe made available by concentration.
 me principal ore zone, as exposed in INe Old Dominion workings, occurs aOoDg a displacement that strikes SoalheaSt and southwest and has a steep dip southeast, The hanging wall consists of limeStones and quartzites which are assigned by RansOme* to 'oe early paleu2ic, while the footwall Nnldbase Of more recent origin. The 'alItlng seems Co have occurred both OeiyTe and after the intrusion of the u'aOase. Most of the ore SO far has "eeh taken from the region of the hanging wall, where it occurs in rude-
 'enucuIar bodies lying nearly paral- 'el Io the bedding of the enclosing ,,meStones and quarlzites. The ore 'a'ofS especially the contacts between '"e uIherent rocks, though not infre- q'ently It iSSuTrounded completely by ,"'eS'ohe'. One of the largest lenses ,p'' mas been found was opened on the ,"' second level along the bedding ''"ue separating the limestone and the I"usrlyl0g quarlzite; 1t is said to nave nave measured 200 feet in length, 100 feet " w
 'uc oHldHed ores, which until re- ''"uy We're alone exploited. consist a.', ',"' "I cuprite in gangue of iron
 H'ucH and quartz. Masses of mala. ,",Ce and chrysocolla are intermixed "''" tlIs ore, and some parts of the I'.r ,.'' 'nefe are large bodies of specu- oo, ,,, aematite carrying only small per. ''nIage of copper.
 i. "' occurrence of sulphides, which ,r S'"7h'ldl Jo the successful issue of ,. , present scheme of metallurgical ,J Js'''l.eht, has been established by ex- n, ,''"'l'n in the lower workings. ra,'T ,',S' ores begin to appear on the fifth oI ,I,e' at depth of $50 feet, and on the in cu "'u and twelfth levels they are ,,,., ''' TyrIte and chalcocite are the A. n,,l, continent minerals, the latter, tbo ,, s'' oe expected, being found in wbos', "uS,'lon zone below the oxides, bv U ''aH probably been deposited -,s''' 'i secondary concentration. tricI cSI'',ogy , of the Globe Copper Dis. Upit,d1 d1IIM ma. By r. l.. Ransome. fssSiSoU,I2 firU I2'ates ates Geological Survey; Pro. lgO3 ' r"per No. l2, Washington,