Quote from Stayen on 2016/07/20, 01:07

Mesa biomes, starting from Minecraft v1.10, produce up to 20 gold ore veins per chunk, with height (y coordinate) within (32, 79) (inclusive).

I have checked that (found a distant Mesa biome in Darklands and mined a chunk down the mentioned y coordinate). Single chunk generated 140 gold ore blocks. Also, every chunk still generates an average of 8 gold ore blocks located below height level of 32.

So, look for Mesa biomes (all types); now they became a Minecraft version of Eldorado.