COROCORO COPPER DISTRICT OF BOLIVIA 81 



MINING OPERATIONS 



The mines of the Corocoro district were formerly in the 

 hands of numerous operators, but the ownerships were 

 gradually consolidated so that for a number of years all the 

 active mines have been under the control of the two com- 

 panies, the Corocoro United Copper Mines, Ltd., and the 

 Compania Corocoro de Bolivia. 



The active mines of the Compania Corocoro de Bolivia 

 are the Remedies on the north slope of Cerro Corocoro, 

 and the Capilla, San Augustin, and Malcocoya on the ridge 

 and in the valky northwest of the city. Prior to the 

 installation of the flotation plant, they were all producing 

 native copper ores and some high grade sulphide and 

 brochantite shipping ore ; but since 1918 only sulphide ores 

 have been produced. The Remedies mine is developed 

 by a tunnel which enters the Cerro Corocoro at the San 

 Francisco mill and by the Remedios shaft which cuts the 

 tunnel at a depth of 60 m. The lowest level is 570 m. 

 below the surface, but only the levels within 210 m. of the 

 surface are now being worked, this being the lower limit 

 of the sulphide ores. The Malcocoya is the newest of the 

 four mines and was opened in 1915. 



The production of the Corocoro United Copper Mines, 

 Ltd. has been derived chiefly from four mines on the Cerro 

 Corocoro, the Challcoma, Gullatiri Grande, Santa Rosa, 

 and Vizcachani. All of these mines produced native copper 

 ores until the completion of this company's flotation mill 

 in 1919, when the Vizcachani operations were divided 

 between the sulphide ores of the upper levels and the 

 native copper ores of the lower levels, and due to the slump 

 in the copper market the other mines were temporarily 

 shut down. In the ridge north of the city, the old Estrella 

 mine and the Copacabana, 100 m. to the north of the 

 former, have been cleaned out and wide bodies of sulphide 

 ore are being developed in them. 



The Challcoma mine is worked through a shaft 360 m. 



