This is a working blast furnace I made in Minecraft 1.6.2.
For those who don't know, an Iron Blast Furnace is a gigantic furnace that smelts iron ore, coal and limestone into "Pig Iron" where it is shipped off to Steel Mills to be made into steel or elsewhere for any iron products. It could also be transferred as molten iron in "Torpedo Cars" to a steel mill if it is in short range away. Iron ore, coal and limestone are loaded into these small cart like vehicles called "Skip Cars" that ride up the side of the furnace and dump the materials into the furnace to be smelted (I replicated this with minecarts in my version). Once the materials are smelted, they "Tap the Heat" and allow the molten iron to flow out into seperate channels where it can be loaded in multiple torpedo cars. Slag, or the waste material is skimmed off and sent elsewhere in Slag Cars and the Iron is carried away to its destination.
Anyways, on this Blast Furnace, minecarts take the neccessary materials (Iron Ore, Coal and Stone) to the top of the furnace and dump it in through a series of hoppers. The items in the hoppers then go through a sorting system, where iron is placed into a regular furnace along with the coal, and the stone is sent out to be the slag in the iron making. The Iron Ingots and Stone are then sent through more hoppers hidden under lava (Meant to represent Molten Iron) and can be loaded on to minecarts and taken away on a bridge classified as a "hot metal bridge". They were designed to prevent molten iron from leaking out of a car and hit the river, causing it to explode. Only 7 were made back in the day. After crossing the hot metal bridge, it goes into the steel mills to be made into steel ingots.

This is a W.I.P. build, as I still have many MANY things to do with it, but I though I'd finally go out and share it with some people
Based off of Carrie Furnace 1+2 in Homestead, PA.
Well on that note I say, goodnight fellow Planet Minecrafters