44 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 58 



BOLIVIA (Continued) 



Abstract: Mg.. Journ. Railw. Comm. Gaz., Vol. 84, 1908, London, pp. 37-38, 91-92. 



Reviews the uses and production of tin to p. 31; describes Bolivian deposits and 

 their production to p. 68. The remainder of the bulletin describes investigations 

 in the provinces of Huancane and Chucuito, department of Preno. Tin was found 

 at but one place in Peru, on the mountain Calvario in Vilque Chico, where it 

 occurs with lead. 



180a. RUMBOLD, WILLIAM R. Origin of the Bolivian tin deposits. 



Econ. Geol., Vol. 4, 1909, Lancaster, pp. 321-364, map, figs. 31. 



Abstract: Mg. World, Vol. 31, 1909, Chicago, pp. 1063-1066. Map. 



The tin ore occurs in Devonian quartzite and quartzite-schist and in quartz 

 porphyry cutting these. 



The Concordia lode is in a breccia in a fissure, part of which is occupied by 

 quartz porphyry. Besides cassiterite, the lode carries siderite, tourmaline, sphalerite, 

 and pyrite. 



The Elisa and Coya lodes as exposed where worked, are similar to the Concordia. 



The Monte Blanco mine, besides having lodes, has schistose quartzite, carrying 

 cassiterite and tourmaline between the laminae. 



The Barrosa Cota Mine works white quartz veins, carrying pyrite, magnetite, and 

 tourmaline, with cassiterite which in some places takes the form of wood tin. 



The San Roque and La Boliviania mines work the " Gallofa " lode, which carries 

 iron oxide and pyrite, arsenical pyrite, chlorite, and tourmaline. There is no 

 igneous rock exposed in the mine. 



At La Unificada Mine, Negro Pabellon, the lode carries cassiterite with iron 

 oxide, quartz and barite. 



Wolframite occurs in veins and pockets of the quartz porphyry. 



in the Cataracagua lode at Huanuni, the writer thinks the cassiterite may have 

 been deposited later than iron oxides. Little sulphide has been encountered along 

 the lode. 



The Morococala mines are in ah inlier of quartzite schist in andesite. A great 

 flow of andesite covers much of the tin-bearing rocks and many of the tin mines 

 are located around the edge of the andesite which, however, has no relation to 

 the origin of the tin ores. 



The Antequera, Totoral, and Avicaya mines at Chualla Grande are on impregnation 

 lodes in quartzite and carry cassiterite, quartz, tourmaline, iron pyrite, and less 

 chalcopyrite. 



In most of the Llallagua and Uncia veins, there is little impregnation but the 

 walls are slickensided. The average width of the veins is about 2 feet. They carry 

 much iron oxide in the upper portions; below that, sulphides of iron, bismuth, 

 arsenic, antimony, a little silver, and traces of gold. There is no stannite. The 

 writer considers these to be the richest tin mines in Bolivia and probably in 

 the world. 



The San Jose 1 lode is 2 metres wide and carries 20 per cent tin. 



The San Salvadora lode is 2 feet wide and is said to carry 25 per cent tin in 

 dense sulphides. It also contains values in bismuth and silver. He claims that 

 with proper handling, the barilla could be made as clean as the tin concentrates 

 from the Malay Peninsula and cleaner than those from Cornwall. 



Descriptions of numerous microscopic sections by Charles P. Berkey are quoted. 



SPENCER, L. J. See No. 1641. 

 181. STEINMAN, G. Ueber die Zinnerzlagerstatten Bolivias. 



Monatsber. deutsch. geol. Ges., No. 1, 1907, Berlin, pp. 7-9. 



Translation: Mg. Journ. Railw. Comm. Gaz., VoL 81, 1907, London, pp. 453-454. 



Translation: Informaciones y Memorias, Boletin de la Sociedad de Ingenieros, Vol. 

 9, 1907, Lima, pp. 133-136. 



Gives geological data on the tin deposits of Bolivia, additional to that published 

 by Stelzner. 



