I haven't spent a minute in gold mining :) but, according to numerous Russian sources, processing of "technogene tailings" - secondary product left after extraction of some other "strategic metals" (and easily extracted gold sometimes), you do save time and money on "mining" but lose big on extracting (which requires expensive modern technologies) and reclaiming of the land (very expensive process). In general, this considered to be very time and money consuming process. That's why the volume of gold production "from tailings" is steadily go down in Russia.