DIAMOND MINES OF BRAZIL 189
prescribed
time is allowed in which to commence operations and make them
commensurate with the concession, at the expiration of which, if
satisfactory work has not been done, the claim may be reentered by
another.
Altogether,
the laws and conditions favor individual digging under a mining
license. The concessioners and leaseholders usually find it to be more
safe and profitable to allow miners to mine on their concessions for a
royalty of from one-fifth to one-quarter of the value of the diamonds
and carbon found, than to attempt to mine on their own account with
hired labor. As the miners sell the diamonds to the field buyers of the
cities, and the latter arrange to inform the leaseholders of the amount
handled, and in some cases to reserve his royalty, the owner of the
concession gets in that way more than would escape the thievery of
hired labor to him, and with less trouble.
The
field-buyers of Bahia, who represent a number of exporters in Bahia
city, work independently, and the miners get the equivalent of outside
market rates less costs and a fair profit for transference from the
fields. The miners usually store the cascalho and wash it week ends.
They are very expert in picking diamonds and carbon from similar stones.
The
world's supply of carbonado, or " carbons " as the stones are called,
comes from the Bahia fields. They are found with the diamonds in the
Paraguassu diggings, and were first discovered in 1843 in grupiaras at
San Jose, district Sincora. Prior to 1856 they were thought to be
valueless and were thrown away. It is said that there are swamps in the
diamond fields, beneath which the diamondiferous deposits disappear.
These deposits
