Why can gold standard be kept for so many years? Because the gold reserves are limited, and gold is a metal easily to be weighed and kept without too much wear and tear. It's an ideal way to measure values.
In other words, if gold can be extracted as much as we want, it cannot serve as a measurement standard and won't have the function of maintaining value. If the gold miners' profit goes up due to the quantity of gold extracted, then the value of the gold is sure to go down. That is to say, the more gold the miners extract, the lower price of gold can be expected, on the basis that the whole social wealth is a fixed amount. Maybe this can explain some reasons why the stock prices of gold-miners don't rise as ideally as they should do.
Of course, gold is a measurement to the wealth. In such a slump economy, its value-maintaining character is sure to be reflected in the high price marked by depreciated nominal currency. But another reason may be the overheated expectation hovering on its value-maintaining function, which results too much money inflows on the precious metal. After all, price is decided by the basic value, and the price will finally return to its proper value in the long run.