I took a quick look and far as I can see Infernum did set it up for you to be able to add more rocks, If I saw right you can add another one like this:
{effect = CONST_ME_BLOCKHIT, ore = 28420, amount = {1, 1}, skillReq = 10, veins =
{
{id = 28425, lv = 1}, --rock with the ore...