There are several mini mills in Australia and quite a few in the USA and they produce a considerable amount of steel from what is essentially quite a small plant. So what is a mini mill?

STEP ONE Scrap steel is delivered by truck and tipped into the mill's scrap pit which has a capacity of 18,000 tonnes - carefully divided into four grades held in separate bays. That's enough to feed the mill for two weeks. STEP TWO According to the demands of the furnace production schedule, the various grades are loaded into scrap buckets for transfer by rail trolley into the melt shop.

A mini mill is a steel production facility that uses an electric arc furnace to melt the scrap steel. In contrast, the traditional Integrated Steel mill has blast furnaces or basic oxygen furnaces using iron ore and coke as the basic ingredients with some scrap thrown in. Although some integrated mills have electric arc furnaces for specific purposes, the arc furnace is the key component of a mini mill.

Over the past 20 to 30 years, there has been substantial growth in mini mills. In 1970, mini mills accounted for less than 10% of US steel production. These early mills typically produced between 100,000 and 300,000 tonnes per annum, with the number of grades of steel and product types kept to a minimum. In 2001, mini mills produced nearly half of the steel shipped by United States mills. Nor is it stopping there. Mini mills are no longer mini, with production capacities now approaching 1,000,000 - 2,500,000 tonnes per annum while still using a single but now quite large arc furnace. In addition, the list of grades of steel produced and product types has increased considerably.