What is the ratio of domestic mines to imported mines in iron and steel plants?

Perhaps, some steel mills use imported minerals, and some use domestic minerals. Specifically, it depends on the characteristics of blast furnaces in various steel mills, the requirements of their final products for various elements, the stability and cost of various ore source procurement channels, etc. Production, procurement and sales, the main departments of these three steel mills should coordinate with each other. It can't be said that in order to achieve the highest ironmaking output, the production department requires the purchasing department to purchase raw materials according to what proportion, and it is necessary to consider whether the required varieties are in short supply in the market, whether the price cost is appropriate, and so on.