Afaik the size for wood textures are 2 dds files with 512x512 and 256x256. I think xou need 512x512 for ores. Maybe you take a look in your game folder how big the size for the ores is.
I think your file is too big. There are some threads abour changing textures. Perhaps this could help you.
The DDS file for copper extracted from the archive is 1024*1024 at 682kb
The DDS file I made for copper is 1024*1024 at 683kb
Not sure what to do with it though. I tried to merge it into the archive but that caused the game to crash.