Bronze is a metal made in blockheads. It is made by smelting 6 copper ore and 3 tin ore.
To make bronze you need a furnace, some furnace fuel, 6 copper ore, 3 tin ore.
To make it you simply open up the GUI of the furnace and smelt copper and tin from the tin and copper ore. Then Open up the GUI again and choose bronze. This takes long but it will help you alot with mining, its much faster than stone.