Akt I. — TJte Roasting and Treatment by Chlorine of 

 Gippsland Auriferous Ores. 



By D. CLARK, B C.E. 



[Eead 10th March, 1S98.] 



The chlorination plant at the Bainisdale School of Mines was 

 erected with the dual object of serving as a testing plant and as 

 a means for training students in the treatment of complex ores 

 on a considerable scale. 



The inclined long-hearth reverbeiatory furnace for roasting 

 and the Plattner system for chlorinating were adopted after 

 consultation with Mr. Henry Rosales, M.E., as the best for 

 illustrating in detail the various operations essential for successful 

 treatment. The principal dimensions of the furnace are : — 



Length of roasting hearth, 35ft. Gin. 



Width, 4ft. ■2in. 



Height of centre of arch above hearth, 1ft. 1 lin. 



Rise of arch, 4in. 



Width of fireplace, 2ft. 



Height of bridge, which is hollow and has air-h(4es at the 

 level of the heaj-th above the firebars, 1ft. 6in., and 1ft. 

 above hearth. 



Slope of hearth, 1 in 9, with six rabbling doors, 13in. by 9in. 



Owing to some misunderstanding when being built, the height 

 of the roof above the hearth of the furnace was too great, and, 

 though roasting may be satisfactorily performed and a tempera- 

 ture much higher than is necessary be obtained, a greater 

 consumption of fuel is entailed, owing to the larger volume of 

 air passing into the furnace and the gi^eater distance of the roof 

 from the hearth. 



The auriferous ores which have been treated consisted usually 

 of sulphides and sulpharsenides, together with heavy oxides 

 concentrated either at our own works or in the district from 

 which they came. 



The following list will indicate the commoner minerals, and 

 also serve to show the standard of the gold contained : — 



