Fascinating indeed. Here is a related article about an explosion that happened while trying to restart a chilled furnace: http://www.hse.gov.uk/pubns/web34.pdf
One thing these news stories don't do a good job of getting across is exactly what a blast furnace is. So here's what I got out of that link: a blast furnace is something like a 10-story can, lined with fancy insulating bricks and a ton of embedded pipes for water-cooling so that the insulation doesn't melt. On the outside are a bunch of walkways and vents and ducts and pipes and stuff just like a scene out of Terminator.
You chuck various rocks (iron ore, limestone, coal) into this multi-story brew and they gradually react with each other (the mixture heats itself) as you blow oxygen into openings at the bottom. Over a period of weeks the iron sinks to the bottom (and the waste sinks close to the bottom but not quite) where you extract it. Once or twice a decade you might stop making steel and empty it all out so you can replace the bricks and do maintenance.
If you let it get too cold, the iron and the waste (slag) will freeze and clog the vents, so you drill into it with "a long, consumable, steel tube fed with pressurised oxygen gas" - it's not like you have heating coils built in, you just toss the fuel in with the rest of the stuff. I guess this is also why the "chilled hearth" at the bottom is such a problem (the point of having a blast furnace is that it's mostly-iron that collects down there, not fuel). Of course, the frozen steel and slag is still insanely hot, just solid now. On the other side of problem-land: if the cooling system leaks and too much water gets in, the whole thing might explode and jump about 2 or 3 feet in the air (this "too much water" is on the order of tons, mind you -- this can happen if parts of the cooling system melts).
Yeesh. I'd been thinking they'd lost something an order of magnitude or so smaller -- more like the size of a cement mixer.
And of course each of your top experts (water systems, electrical systems, etc) might want to go home before the 10+ year campaign is over, so you install remote monitoring and if there's a crisis you call the top expert and he can take a look at it and provide advice instead of getting up and spending half an hour to drive there and then give advice (possibly a very useful capability in many other crises)...
Chucking stuff in is close to the truth. In research furnaces they lob bin bags full of various materials they want to add to the cast depending on the grade of steel they're trying to produce. The whole bag goes in, the plastic is negligible.
Often these things are heated (at least initially) with big ole' electrodes or by using induction. Nominal current is in the kiloAmperes. No pacemakers please!
To put it into perspective (again), most steel plants have their own dedicated power stations on-site.
