There are two commonly utilized ways of making steel on the primary end. The first is known as an "integrated" mill, which is the more "classic" way and uses basic oxygen furnaces to generate a liquid steel base from pig iron to which they'll add the proper alloys to it later. The pig iron is generated in the blast furnace from iron ores using natural gas.
The second is the "mini" mill, which utilizes electric arc furnaces to melt scrap down as seen in the OP. This is a relatively new technology and there's perks and downsides to each. Perks of the mini mill includes a lower operating cost as long as scrap prices are fairly low. Scrap prices are quite dynamic though, so you're at the mercy of the market here. There have been times where scrap prices are so high some product would have made more money selling it as scrap then actually shipping to the customer. That doesn't happen often though, and has helped Nucor (a company consisting primarily of mini mills) to rise above some of the long tenured integrated mills in recent years.
Another drawback of mini mills has traditionally been lower quality for surface critical steels. This means it hasn't been able to make the surface quality required from auto makers and such for their body panels. But they're getting closer every day.
