Arizona weekly citizen., 1883-03-25
A CHAPTER ON COPPER.
Hsw Co Calculate the Value oT Lode The Location or Smelling works-Ths Metailurgy of Copper.

2
 The Location Of Smelling works-The
 Metanurgy of Copper.
 s. r. Exchange.
 The writer of the following does not claim any originality. 1t is something every practical miner knows, that the original form in winch copper exists ln velns IS the sulphUret of copper or cop per pyrites.
 All other copper ores, in combination with oxygen, or chlorine, or iron, or sul- phur are in all cases the result of the decomposition of copper and iron py- rites and other sulphuretted ores which formed the original yein.
 Among the first things to be noticed on a cupriterous vein n the decomposed state Uf the upper portion, and back ur uutcun, consisting of a reddish or brown Ish mass of a light spOngy condition. IL IS a mixture of oxide of Iron and usually contains traces Of other metals Tn the form of oxides. carbonates and sulphu- rets, but containing in most cases no copper at all, until tine vein bas oeen de- veloped to a depth of 70 to 60 feet to that point. or line of decomposition, or ss far as Inc atmospheric agencies Lave any influence The sulphuret of copper is oxidlZed into 0 sulphEte, which Is sol uble in water, and earned away n the rains and streams, leaving the insoluble peroxide of i.On as sangue m the lode
 By long expenence, the inner is en
 bed to form aE uIaltun, With some Con- fideuce, of the value ,i she lode. from the character of i.s out-rOp; and tne de- c ,muos,.d state uf sne upper portions oi d vein k by every prOspectOr looked up- 5u as favorable indication of valuable ,res at some depth below.
 The nature of th5 rocks IS examined with great care by the miner; some kind. oi rocks being more favorable to tne development of ore than others, Il l l. certa lr that tue metalliferOus contents ! 1f veins wary with the character Of the .pclosIug rocks. With the exception of ] iron the ores of no metal are more gen- erallv ciStriuu:cd than those of copper. | Each of the chief members Of { Ie strata which compose the solid earth crust | have been found penetrated more or | ess by its lodes, and the miner has nOi | tailed to recognize the fact that the | formation has an important influence | on the character of the lode. It IS oi | importance, in calculating tue value oi ! a lode, to take the dip m considers ] -ion, as iu case Of lode which varies tu its dip, those portions which approach | nearest tO perpendicular are the Tlcn | est, and the workings upon hssure l vein are those ia which the yleld Is of a | .nore permanent character, and n whicL | -he mining interest has attained tue | rrtatest development, although segre- 1 gated veins have produced large amounts of ore. The sOftuess and tsushness make copper very valuable -or a great variety Of purposes, and the l ancient historIaas meutlODed that Its
 use WAS known t5 mankind at a very ] aarly date.
 As gold is the only yellow metal, SC l copper Is the only red one. The speci- l ic gravity Of the pure native metal ls
 above S. Itis often found ID a state of ] absolute purity, beng, however, the result of The decomposition of the sll- 3hurets. Ih0-e are some questions
 which atand at the head of all metallur- gical processes, and these require the ! most careful consideration.
 First What Is the nature and what are the amounts of substances with ' winch the copper Is combined.
 Secondly hat percentage Of copper ! Is contained m the ore?
 i Upon the reply must depend the value of the ore O. compound Tn regards to the amount of copper possible to obtain from it. as well as the character of the processes that must be adopted to ob- tain She pure metal The processes used m the reduction of copper ores are va- irons and numerous, and peculiar in de- tail to each.
 The question of fuel is also one of primary importance, and upon the abundance and cost O. supply depends largely success and profits, and the posi- tlOn Of the supply of fuel has as much to do with the location of the smelling works as the position of a mining dls. trlct. The metallurgicgl treatment of copper ores Is a process requiring much skill and large amount of capital. Moreover, II is usually advantageous to mix together ores Of different qualities so as to be able to smelt the poorer and more refractory kinds by mixing them with the richer. There are two methods employed ID the ms.allurgy of copper the '.dry way" and the wet way" The first is employed with advantage in the proximity of wood and coal and con- venieuc7 of access. The secoud method enables the mesailurglst to sepatcte more completely the different metals besides, less fuel Is required and is mo-c suitable ID regions poor ID wood, coal and transportation facilities.