METALLURGICAL METHODS AT BROKEN HILL. 279 
economical means which can be used to allow of the ore being 
stacked underground until the results of its value are out. The 
demand on the mine by the smelters partly brings about such a 
condition of irregular values in the ore, and nothing can be 
devised to remedy it, when a mine has a body of ore which is so 
eccentric in value as that of the Proprietary, and has to keep up 
its weekly tonnage and output, except large bedding floors. From 
these remarks, the study may be slightly seen which the man in 
charge of the furnaces has to make of the character of the ores 
being smelted. Regarding the slag that will be made, he contents 
himself by forming an opinion of the silica contents of the ore as 
it lies in the furnace supply bins, and on that opinion adheres to 
or changes the running furnace charge. In addition to that, he 
studies his furnaces and notes all the various signs of the tuyeres, 
the way the molten slag fall into the slag-pot, the speed the 
furnace is smelting, &c., and with practice will make the right 
change ; but so often does the character of the ore alter from 
silicious to basic, and wice versd, that it is not uncommon to have 
to make from two to six radical changes in the constitution of 
the ore charge every day. Experience of the ores one must 
therefore have to attempt to run the Proprietary blast furnaces 
under the ruling conditions. The absence, then, of bedding 
floors, with such a variable ore, is a serious detriment to 
good smelting. The skill of the most accomplished metallurgist 
would be at fault without he possessed the power to judge, fairly 
accurately, the ore in the bins each morning, and even with 
long practice mistakes are made very often, for a man cannot 
last the whole twenty-four hours of every day, and therefore 
does not see the ore which is delivered from the mine during 
the night; and the basic or silicious change which he had 
made in the charge the previous afternoon might have been 
unnecessary if the ore could have been seen by him _ before 
hand. Hence for some hours an entire waste of flux has gone on, 
which gets to be serious with eighteen furnaces in full blast. I 
am somewhat afraid that my metallurgical critics may not quite 
understand the points in this ore irregularity and the impossibility 
of arresting it, and probably describe the method of the metal- 
lurgist as more guess work than brains, and therefore it is well to 
say that the ‘‘ guessing” point of the problem is assisted in every 
way by regular daily assays of the ores with their principal com- 
ponent parts, such as silica, iron, manganese, and zine, together with 
careful bi-daily slag analyses and slag assays from every furnace, 
made for lead and silver, together with special samples of slag for 
the same metals taken promiscuously from the furnaces during each 
day. With the aid of these very close work can be done, and the 
ability to judge the molten slags, as to their lead and silica con- 
tents, is also of the very greatest assistance to the general end. 
