It
has not been possible to obtain a complete report showing the total
consumption of potassium cyanide and sodium cyanide used in the
recovery of gold and silver in the United States in 1917. If the
quantity used in California, Alaska, and Oregon is added to the
3,710,886 pounds reported to have been used in other Western States the
estimated total consumption was probably several hundred tons less than
the estimated quantity, 2,600 tons, consumed in 1916.
The
figures given indicate the elimination of the use of potassium cyanide
in the recovery of gold and silver, for only about 69 tons were used in
1917 and this was probably from old stocks at mines. The growing
scarcity of potassium cyanide necessarily increased the use of sodium
cyanide. The domestic supply of sodium cyanide was sufficient to supply
the domestic consumption. As the quantity of bullion recovered was less
in 1917 than in 1916, however, the quantities of quicksilver and of
cyanide used were less. The quantity of cyanide used per ton of ore or
tailings treated and the quantity of gold and silver recovered per
pound of cyanide show considerable variations. These variations are
doubtless due in part to greater efficiency in large milling plants in
some of the States but are mainly caused by the difference in the
character and varying metal content of the ores treated.
