Coke oven

#	Colour	Name	Matches
1		Fireclay bricks	game:claybricks-good-fire
2		Empty (air, or a pile of coal, or a charge Pile)	*:@(air|coalpile|furnace-chargepile)
3		Fireclay brick slab	game:brickslabs-fire-up-free
4		Fireclay brick slab	game:brickslabs-fire-south-free
5		Coke Oven Core	iiex:furnace-cokeovencore-*
6		Charge Door	iiex:furnace-chargedoor-n
7		Charge Lid	iiex:furnace-chargelid-s
8		Tall Hopper	iiex:hopper-tall-s
9		Reserved space (kept clear)	exlib:structurefiller
10		Empty (air)	game:air

Materials

Block	Cells
Fireclay bricks	89
Fireclay brick slab	12
Coke Oven Core	1
Charge Door	2
Charge Lid	2
Tall Hopper	2

Facings and connectors

• Fireclay brick slab turns with the structure; segment 3 of its code names the face.
• Charge Door turns with the structure; segment 3 of its code names the face.
• Charge Lid turns with the structure; segment 3 of its code names the face.
• Tall Hopper turns with the structure; segment 3 of its code names the face.

What it does

The coke oven is where coal becomes furnace charge. A shaft furnace burns only what carries the fuel role, which is coke and charcoal and no raw coal at any rank, and coke carries twice charcoal's carbon per unit. Every heat the blast furnace and the cupola pour is therefore waiting on this building.

It is one bank of two chambers sharing a wall, in ordinary fire brick, and each chamber bakes and draws on its own clock. Build it before anything it feeds.

Building it

1. Place the core first. It sits at floor level in the middle of the wall the two chambers share.
2. Ctrl plus shift plus right-click it for the build outline and the shopping list.
3. Lay the floor and the two chamber boxes, leaving each chamber's cells open for its bed.
4. Set a charge door at the front of each chamber.
5. Arch the crown over both chambers and set a charge lid in each crown above its chamber.
6. Keep laying until the outline reports complete.

The core's side variant fixes the facing and the whole bank turns with it. The two chambers are derived from the layout rather than declared, so they follow whatever the drawing says.

Charging and sealing

Open a chamber's door and right-click the bed behind it with bituminous coal. The whole chamber fills from one interaction, charged per cell.

Then shut it, both ways. Coke is made by baking coal away from the air, so a chamber works only with its crown lid down and its door closed; an open chamber never starts, whatever the clock says. The core names the chamber that is standing open.

It takes bituminous coal and nothing else. Charcoal and coke are not coal, anthracite does not coke, and lignite is refused.

The run

1. Charge both chambers and shut all four closures.
2. Light the oven.
3. Read the core. Each chamber reports its own progress.
4. When a chamber finishes, open its door and draw the coke.
5. Recharge that chamber and shut it while the other one works.

Each chamber holds its own clock, which is what the second one is for: one side draws and recharges while the other bakes. Opening a lid mid-bake pauses that chamber alone, and shutting it resumes where it stopped instead of restarting. A full bake is one hour of real time.

What goes wrong

The progress bar never moves. The chamber is not sealed. Both the lid and the door have to be shut.

The clock keeps resetting to zero. The bed holds a coal that does not coke. Only bituminous does.

A tall hopper over the oven holds its load for ever. The hopper charges shaft columns and this furnace has none. Click the chamber bed instead.

One deposit filled both chambers. That is how it works today: the spread is per furnace, not per chamber. Charging is a whole-oven operation until per-chamber charging lands.