624 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.45. 



Peters, E. D. 



The Principles of Copper Smelting. New York, 1907. 



Chapter on pyritic smelting (pp. 213-338) deals extensively with practice at Mount Lyell. (See also 

 Peters, Modem Copper Smelting.) 



Sticht, Robert. 



Ueber das Wesen des Pyrit-Schmelzverfahrens. Metallurgie, Halle, a. S. 1906, 

 52 pp. 

 Metallurgical. 



Stand der Betriebe der Mount Lyell Mining und Railway Company (Ltd.), am 

 Schlusse des Jahres 1905. Metallurgie, Halle, a. S. 1906, 55 pp., 13 figs. 

 Gives geology, method of mining, and treatment of ores. 



Mining and Smelting at Mount Lyell, Tasmania. The Mineral Industry during 

 1907, vol. 16, pp. 385-442. 



Outlines the geology of the deposits, describes the mines and their development, and gives an 

 account of the reduction works and metallurgical treatment of the ores. 



Weed, W. H. 



The Copper Mines of the World. New York, 1907, pp. 163-169. 

 Gives geological description of the Mount Lyell deposits. 



Text-figure: Sketch map of the Mount Lyell District. (Modified from Gregory.) 



EXPLANATION OF PLATES. 



Plate 48. 



Fig. 1. Polished section of typical cupriferous pyrite ore from Mount Lyell Mine, 

 showing schistose pattern resulting from replacement. Natural size. Cat. 

 No. 77549. 

 2. Polished section of pyrite (light) with seams and veins of enargite (dark). 

 Mount Lyell Mine. Natural size. Cat. No. 77552. 



Plate 49. 



Fig. 1. Incipient stage of replacement. Chalcopyrite (white) subordinate to gangue 

 (gray). X 30. North Moimt Lyell Mine. Cat. No. 77571. 



2. Advanced stage of replacement. Chalcopyrite (light) predominating over 



gangue (dark). X 30. North Mount Lyell Mine. Cat. No. 77571. 



3. Chalcopyrite (dark) cementing gi'anulated and shattered pyi'ite (light). X 30. 



Mount Lyell Mine. Cat. No. 77549. Shows that the chalcopyrite was 

 developed later than the pyrite. 



4. Area of primary chalcocite, showing characteristic cleavage developed by 



etching with dilute nitric acid. X 30. North Mount Lyell Mine. Cat. No. 

 77593. 



Plate 50. 



Fig. 1. Enargite field (light) including minute ramifications of chalcopyrite (dark). 

 Pyrite grain to left of section. X 30. Mount Lyell Mine. Cat. No. 77552. 



2. Portion of enargite field of figure 1, enlarged to 180 diameters, showing the in- 



cluded chalcopyrite (dark). The latter, though appearing so in the photo- 

 graph, is probably not a fracture filling in the enargite, but of contempora- 

 neous development. 



3. Bornite (dark) and chalcocite (light), showing crystallographic intergrowth 



between the two, indicative of simultaneous development. X 30. North 

 Mount Lyell Mine. Cat. No. 77593. 



4. Crystallographic intergrowth of bornite (dark) and chalcocite (light). Portion 



of figure 3 with magnification X 120. North Mount Lyell Mine. Cat. No, 

 77593. 



