The primary concerns of the prospector

The primary concerns of the prospector or miner
interested in a lode deposit of gold are to determine
the gold content (tenor) per ton of mineralized rock
and the size of the deposit. From these data, estimates
can be made of the deposit’s value. One of the most
commonly used methods for determining the gold and
silver content of mineralized rocks is the fire assay.
The results are reported as troy ounces of gold or silver
or both per short avoirdupois ton of ore or as
grams per metric ton of ore.
Placer deposits represent concentrations of gold
derived from lode deposits by erosion, disintegration
or decomposition of the enclosing rock, and subsequent
concentration by gravity.