TeraDuke

Hi, I am having trouble getting an ore block to only be mined with an iron pickaxe or higher, and have all the other tools not drop an ore block. I heard that you could use the setHarvestLevel("pickaxe", 4); statement to make a block only mineable by a certain tier of pickaxes. But, when I try it with a wooden - stone pickaxe or shovel/axe, it still drops the block. Sorry if this is a stupid post, I'm extremely new to Forge. Let me know if you need the mod .java files.