Yes and No
Depends how big the deposit, you do notice fluctuations in Gold prices (if you day trade) when SIGNIFICANT deposits are found because new ones of rather small size are found daily.
Currently, the amount of Gold mined in the history of mankind could fill 1/3 of the Washington Monument. If a deposit that could fill the rest was found then DEFINITELY there would be a significant price drop. If the price at the time of the find is $1,250 USD per ounce, 2/3 of that is $425 per ounce because the world supply tripled overnight.
However, the chances of such a deposit found on earth now are slim to none. In the past decade there has been about 3 significant deposits found.
Price of Gold = 1 Ounce = 1 Paycheck
The faster you extract it, the more paychecks you get; just like Bitcoin mining. Bitcoin Mining, very much like Gold mining is a number's game; but remains a game none the less
