Resource chains: coal, ore, and oil from the mine to the export dock

The third economy

After taxes and tourism, resources are the third way a BuildCity economy earns. Unlike the other two, this one is a chain: deposits in the ground are extracted by mines and wells, raw material is either sold as-is or processed into higher-value goods, and goods leave the city through trade buildings by truck, rail, or ship. Each link has a cost, a footprint, and a logistics requirement, and the profit lives in the gaps between them. This article walks the chain end to end and explains the October 2026 changes that made the processing step worth doing.

Deposits: where resources come from

Every map carries a list of oil, coal, and ore deposit coordinates. They are fixed when the map is designed, which is why map design treats resource placement as a gameplay decision rather than decoration: an oil field on an island is a challenge, and a coal seam next to the entrance road is a gift. The in-game resource view highlights deposits, and the extraction buildings only work when placed on or within range of one. Since the autumn updates, a mine or well placed where there is no deposit shows a warning bubble explaining why it is idle, in every supported language, instead of silently costing upkeep.

Processing: smelters and refineries

Raw coal, ore, and oil can be exported directly, and for a long time that was the sensible thing to do. The two processing buildings, the Smelter at 30,000 and the Oil Refinery at 40,000, turn raw input into alloys, steel, and processed petroleum goods that sell for more per unit. The catch, which we found while auditing the economy in October, was that at the standard export prices the inputs were worth more sold raw than the outputs were worth processed. A smelter producing 25 alloy per hour was turning 4,240 worth of coal and ore into 3,500 worth of alloy, and the refinery chain for processors had the same shape at a larger scale.

We fixed it by raising output rather than by cutting input prices, which would have hurt everyone who exports raw. Alloy production went from 25 to 45 per hour, steel from 35 to 50, and processors from 20 to 30. At the standard prices, that leaves a processing margin after the opportunity cost of the raw material and the building's own upkeep, before shared costs like power, mining, and transport. The target was a 15 to 30 percent net margin across a complete chain at regular prices. A chain fed entirely by imported raw material is not guaranteed to be profitable, and that is intentional; processing is meant to add value to your own deposits, not to be a money printer.

Trade: getting goods out

Nothing earns money until it leaves the city. Trade buildings are the exit, and each one uses a different kind of transport with a different footprint and placement requirement.

Exports and imports share one price table per good, and refunds of warehouse stock use the same regular prices, so there is no longer a way to buy through one building and sell through another at a different rate. The October audit also removed a long-standing freight station behavior that paid out a random shipment every ten minutes whether or not the warehouse held anything; shipments now require real stock, a real deduction, and a completed delivery. Between saves, the server limits how much cash trade can add based on the assets and raw inputs it has on record for your city, which is a sanity check rather than a full re-simulation of every truck.

Trading with other mayors

Once both cities own a Trade Center, players can send money and resources to each other. A single gift can carry up to 100 million in cash or 50,000 tons of a resource and a short message, the recipient claims it from their city, and the server performs the transfer. Sister cities get a bonus on gifts between partners, within daily caps. Gifts are the simplest way to help a friend through a utility upgrade, and because they move through the server's claim flow they are also fully validated.

The power connection

Resource chains and the electricity grid are linked. Coal and oil power plants, the high-output options at 500 kW and 450 kW, need fuel, which means either your own coal and oil or imports through a trade building. Wind and solar do not, at a fraction of the output. A city that mines coal can therefore run cheap, powerful plants on the industrial edge and export the surplus, while a city with no deposits may be better off with clean power and a tourism focus. The utilities guide covers sizing the grid; the point here is that your deposits should influence which plants you build.

A resource build order

1. Open the resource view and plan an industrial edge around the nearest deposit cluster, with its own road to the map entrance.
2. Build a Trade Depot first and one mine. Export raw until the depot is busy; this funds the rest.
3. Add a coal plant if you mine coal. Fuel you own is the cheapest electricity in the game.
4. Build the Smelter or Refinery only when you have two or more extraction buildings feeding it and storage for the output. An idle processor is pure upkeep.
5. Upgrade the exit before the input. A Freight Station or Trade Port moves more than another mine produces.
6. Build the Trade Center when you want to trade with other players or need the larger logistics it unlocks.

The buildings reference lists every resource and trade building with its footprint and upkeep, and the budget guide explains how the new per-line expense breakdown shows whether a chain is actually paying for itself.