THE MINES 171 



With the enhirg-ed mill 5.000 cathodes (the copper in com- 

 mercial form) \\\\\ be dipped, and tliese will "ive Bntte & Dulnth a capacity 

 of 1,200,000 ponnds of finished, electrolytic copper per mbnth. 



It would require much space to tell in detail, and in technical form, 

 each step of the leachinq- process, and to the layman this would mean little. 

 In a nutshell tlie ore — which in itself forms a motmtain on the surface — is 

 broken down with surface shots and scooped up with steam shovels. Tt is 

 dumped into' the little cars and conveyed 1)y them to the mill, a few hun- 

 dred feet away, where it is dumperl into the crusher. From the crusher it 

 passes into the rolling mlachine and from there to the leaching machines, 

 a series of wooden troughs, w'here the acid solution gets in its work of 

 extraction, through the aid of agitating wheels and paddles that keep the 

 solution stirred. This is then passed on to the electroylitic cells or tanks 

 where the copper is precipitated onto copper sheets, or cathodes, by elec- 

 trolosis, and these cathodes are then in the form of commercial copper to 

 ship to market. 



Thus has Butte entered into the surface, or pit, mining field. At the 

 Bullwhacker they have extracted their ore through a great pit, known as a 

 "glory hole." At the Butte & D'uluth the process is to dig right into the 

 side of the hill, starting near the top and stripping off the 

 Results ground in tiers of about twenty feet each. A few years back 



That Have experts said these mountains of low^ grade copper ore were 

 Astonished practically worthless — that the grade was too low to make 

 the Experts, mining profitable. And so it Would be under the. old methods 

 of treatment. But with the leaching plant right at the prop- 

 erty and with the process 01^ extraction, or precipitation, bronght to* such an 

 economical basis, the question has been solved and the low grade copper 

 Oire is now beiing mined and shipped to market at good profit. The Bull- 

 w^hacker ores average four per cent copper and the Butte & D'uluth about 

 three per cent. 



The two leaching plants related are but starters. Others are sure to 

 ._uiiie. John D. Fields, manager of the North Star property of Granite 

 county, has established a big leaching plant there for the treatment of his 

 oo'mpany's ores. And the Anaconda company is also entering the new field. 



And so another branch has been added to Montana's mining industry 

 and no matter how low grade the copper ores, even down to one per cent, 

 the mineral values can be extracted at profit by the leaching process. 



Before leaving the subject of copper there is one point quite worthy 

 of emphasis here and that is copper mining in Montana is getting better 

 with depth. That also is quite significant for it proves the theory of per- 

 manancy adhered to bv John O. Ryan, president of the Amal- 

 Depth gamiated Copper company, that the ore exists at very deep 



Seems Only levels. 



to Add to Until twelve years ago ISTontana had not seen deep mining. 



Values. Even the Butte mines had not been worked to the lov/er levels. 



Silver ore had been found in the early days of the camp near 



the surface and many old-timers thought the mines were wortMess when 



— Comparisons may be odious, but they breed pride in Montana. 



