of
the bullion, either base or unrefined, is readily known. In the third
item the refining loss and in the fourth item the combined
concentrating, smelting, and refining losses must be considered. In the
case of the precious metals the concentrating losses may be large and
must be allowed for, but the smelting and refining losses are known to
be very small and in ordinary practice to be more than offset by
certain gains. These gains are of small quantities of precious metals
(not paid for, but actually recovered from ores of copper, lead, and
zmc) and certain differences in quantity of gold and silver between
actual recovery and basis of settlement—for instance, silver is usually
paid for on the basis of 95 per cent of the current New York price and
gold at from $19 to $20 per fine ounce. From this it is seen that
producers reporting in terms of dollars only will frequently be giving
figures corresponding to production below actual final output of metal,
and if they erroneously report net proceeds, as they sometimes do,
their figures are still further below. Other gains offsetting refining
and smelting losses are the relatively small quantities of precious
metals, principally gold, not regularly reported from the mines, but
coming from transitory placer miners whose production escapes estimate,
from stolen ore treated in improvised "assay offices," and from smelter
and refinery cleanings and similar material. Although mine reports in
the aggregate may appear, therefore, to give figures of gold and silver
that are too high, it is known from actual practice and comparison,
later discussed, that final recoveries, especially for gold, are
somewhat in excess of those reported from the mines.
COMPARISON OF MINT REPORT AND MINES REPORT.
Of
the two plans outlined for ascertaining the gold and silver production
of the United States it may be said that the one is a measure of the
mining industry and the other a measure of the metallurgical industry;
the one reports the production and recoverable content of mine output
and the other the metal actually recovered in marketable form. The two
methods will not produce exactly corresponding results nor should they
be expected to do so. In addition to factors already noted as causing
differences between the two sets of figures, it must be remembered that
it is not always a simple matter for smelters to distribute their
output according to the exact origin of the ore, and it is still more
difficult for refiners to do so. It is therefore always possible that
some ore of Canadian or Mexican origin is contributing to the output of
metal thought by smelters to be of domestic origin.
The
calendar year covered by both investigations is the same, but the
period of mine production naturally corresponds to a period earlier
than the period of actual production of marketable metal by the
interval of time necessary for transporting, sampling, and treating the
ore and for refining the products. This interval is practically
negligible in the case of placer and mill bullion, but may be several
months in the case of crude smelting ores and especially of ores
concentrated before smelting.
The
figures for the mint report and the mines report for a period of years
sufficiently long to compensate for overlap or lag should agree
