2i8 Bulletin of Laboratories of Denison University. |Voi. xii 



free quartzite, I feel reasonably certain that an additional source 

 of the iron oxide not considered by Hayes, is derived from the 

 oxidation of disseminated pyrite through the quartzite. The 

 source of iron oxide from this direction may possibly have been 

 of only secondary importance. 



Economic Features. 

 Methods of Mining. 



The ocher-deposits to be mined in the Cartersville district 

 form extremely irregular branching veins, which intersect the 

 rock in almost every direction. The ore-bodies may occur en- 

 closed in the hard and fresh quartzite, or they may be entirely 

 enclosed in the residual decay derived from the quartzite. The 

 bodies of pure ocher are usually soft and clay-like in character, 

 and the ore is easily mined with the pick and shovel. They 

 are generally exposed along the slopes and summits of the 

 quartzite hills and ridges. 



On those properties in the district where systematic mining 

 has been done, the method employed consists of tunnels driven 

 into the ridge, from which drifts are worked at suitable points. 

 In this way a number of levels have been worked, one above 

 the other, on several of the properties. Occurrence of the ocher 

 in the fresh rock, as on the Georgia Peruvian Ocher Company's 

 property at the wooden bridge across the Etowah river, at times 

 necessitates blasting. (See Fig. 4). 



Timbering is necessary in the tunneling, as caving is apt 

 to occur. The undergound-mining is also extensive enough to 

 necessitate tramways and lights. The tram-cars are drawn in 

 and out of the mines either by mules or by means of steam and 

 cable. Both are in use in the Cartersville mines. 



Preparation of the Ocher. 

 The only preparation necessary involves the separation of 

 the ocher from its mechanically admixed impurities as mined, 

 which consist principally of clay, .sand, and manganese oxide. 

 These are freed from the ocher by a process of washing in run- 

 ning water, floating, and settling of the ocher in vats, from 

 which the water is evaporated. 



