294 PROCEEDINGS OF SECTION B. 
land. Plenty of ore, of good value, has always enabled the com- 
pany to pay good dividends, and the loss arising from escaping 
flue dust has not been felt. 
Larger flues, with plenty of impediments to check the current 
in the shape of baffle walls, would certainly have cost a consider- 
able sum, and in the position in which the furnaces stood would 
have been almost impossible to build ; but had the furnaces been 
better placed to allow of long flues being built, the latter would 
have paid for themselves long ago, besides preventing the distri- 
bution of an undesirable substance on the land. Vegetation was 
not damaged by it, for the simple reason that there was none to 
damage, and it is doubtful if the general health of the town 
suffered in any degree. 
REFINING OF THE BULLION. 
Although this was not carried on in Broken Hill, still it is so 
closely associated with the ore treatment that it might be well to 
give a short description of the work. The refinery is situated at 
Port Pirie, in South Australia, on the sea coast. The spot was 
chosen as being about the most convenient place, having a water 
traffic for the largest ships ; in the centre of a good flux district, 
and with its sea advantages, coal, coke, and stores were landed at 
a price very considerably below the cost in Broken Hill. The 
last year or so the company have found it to their advantage to 
refine the whole of their output of lead due to the extortionate 
charges and deductions made by English refiners. The plant is 
capable of handling some 800 tons of silver-lead bullion weekly, 
and is very complete in detail. It was designed by Mr. H. H. 
Schlapp. 
THE PROCESS. 
The silver-lead bullion is first put into 50-ton reverberatory 
furnaces, where it is melted down slowly, so that as much of the 
impurities which it contains may be taken out at the commence- 
ment. This impurity or dross, as it is styled, consists almost 
entirely of an alloy of copper and lead with silver, one part of 
copper taking up sixteen to seventeen parts of lead. When the 
lead is all melted down the layer of dross is skimmed off clean. 
The heat is then raised, and by degrees the small percentages of 
copper, antimony, iron, sulphur, &., are skimmed off, leaving in 
the furnace a soft, easily-marked lead and silver bullion. This 
operation takes some twelve or more hours to finish. From the 
furnace it is tapped into cast-steel kettles of 50 tons capacity. 
By the aid of a fire under the kettle the lead is made red-hot, 
and a small percentage of metallic zinc, from about 14 per 
cent. by weight downwards, is added. ‘This is well stirred in 
for some half hour or longer, and then the contents of the 
kettle are allowed to cool down considerably. As soon as the 
