STATISTICS OF THE COSTS OF WORKING AND THE YIELD OF GRAVEL.
showing the costs, the quantity of material washed, and the
corresponding yield of gold are rare and difficult to obtain. In the
early days of placer-mining in California the question to be solved by
the miner was not what the gravel would yield per cubic yard, and what
it would cost to move it, but rather how many ounces of gold-dust he
could "pan out" or "rock out" between sunrise and sunset. What the
miner required was that the daily yield in dust should exceed the cost of living, etc. When it fell below this he moved his camp to other grounds.
wonderful productiveness of the river bars and shallow placers,
attested by the gold bullion and dust shipments, created an
extravagance usual to all new and rich mining countries, the baneful
effects of which are still felt.
the richest and most easily worked placers became exhausted the
increasing necessity of mining on an extensive scale and with ample
capital led to the formation of large companies. Then became evident
the importance of determining beforehand the amount of gold in the
various claims and the costs of working them. This last included
various engineering problems, as the best grades, the duty of the inch,
etc. In this manner the first data concerning the yield (commonly
estimated per cubic yard, but very often, for the sake of convenience,
per inch of
water) of the auriferous gravels were published. Many