How did mining methods change when gold became more scarce

Question

i need this now for a project

Answer 1

The easiest gold mining method is placer mining - basically finding it in rivers or streams.  Next is following veins, literally digging it out by hand.  As gold becomes scarce and more disseminated heap leaching is used, removing large volumes of lower grade ore and letting a cyanide solution percolate through the heaped, or piled up ore.  The gold continaining cyanide solution is filtered out and recovered by heat.

Answer 2

Gold has always been scarce.  As gold prices go up, it becomes more economical to process low-grade ores that may have not been worth mining when prices were lower.

Grandpa