TEEATMENT OF THE COMSTOOK OEES. 249 



No. 4. Wheeler Pans : Charge of ore 1,000 pounds ; 2 or 3 pounds 

 of salt ; 3 or. 4 ounces of sulphate of copper ; 30 to 50 pounds of quicksilver, 

 put in when the pan is charged. Steam used directly. Time in pan, four 

 hours. 



No. 5. Chiefly Wheeler Pans : Charge of ore 1,000 pounds ; salt 6 

 pounds to each charge ; subsequently the use of salt was abandoned without 

 affecting the result ; sulphate of copper IJ pounds ; quicksilver 75 pounds, 

 put in after every clean-up, subsequently 35 pounds with each charge ; a 

 quantity is also kept in the separators. Steam is used directly. Time in 

 pan, four hours. 



No. 6. Hepburn Pans : Charge 1,400 pounds ; no salt used ; sulphate 

 of copper, from 3 ounces to 2 pounds, put in with the charge ; quicksilver 30 

 to 50 pounds, added with the charge. Steam used in chamber and direct. 

 Product of the agitator, also product of reworking slimes, returned to the 

 mine. Time in pan, four hours. 



No. 7. Wheeler Pans : Charge 1,500 pounds. No salt used. If pounds 

 sulphate of copper, added in solution ; quicksilver 60 pounds, put in with the 

 charge. Steam used in the chamber. Time in pan, four hours. Slimes, 

 which in some mills are mixed with the sand to be worked in the pans, are 

 never treated in this mill. The superintendent attributes to this much of 

 the efficiency of his work, experiments having satisfied him of the evil effects 

 of thus mixing slimes with sand. One ton of ore is thought to produce about 

 one hundred and fifty pounds, or from seven to eight per cent, of slime. 



No. 8. Pans, reconstructed Wakely ; in effect, large Wheeler : Charge 

 1,500 pounds. No salt used. Sulphate of copper, one pound per ton of ore, 

 added after grinding the charge one hour ; quicksilver 75 pounds, added with 

 the copper. Steam used in chamber. Time in pan, four hours. This mill 

 having large tank capacity, the stream of pulp from the batteries has unusu- 

 ally protracted opportunity for settling, and, in effect, the foreman reports 

 that the water runs from the last tank " clear enough to drink." The final 

 tanks contain the sHmes and these are mixed with the coarser sand, in the 

 proportion of one-third of slime and two-thirds coarser sand, to be worked 

 in the pans. Without attaching undue significance to this note, it is inter- 

 esting to contrast with it the note on No. 7, and to observe that the results of 

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