Help me, you benevolent geology nerd!

This is a question I'm trying to find a workable (but not necessarily precise) answer for a colony-building sci-fi RPG game that I am GMing for some of my friends.

So, the setting is on the harder sci-fi spectrum where faster-than-light travel is impossible. Players arrive at the planet in a futuristic form of cryosleep, and they are the only fully grown humans (the rest are frozen embryos to be incubated on site). Mass was a main concern for the trip, so the ship carried only the necessary equipment to extract resources on site and print them in the colony.

Now, let's assume that the colonists have: 1) An automated industrial sci-fi printer capable of smelting minerals and producing chemicals, if supplied with raw resources, as well as assembling them into useful components; 2) A swarm of drones capable of mining, farming, and building. More drones can be built with the printer once resources are gathered; 3) And I suppose this sci-fi society would probably be prepared for interplanetary exploration, so they would have streamlined most of their technology to use the bare minimum amount of resources necessary and use different elements as substitutes (I'm not sure if this is too far-fetched for a hard sci-fi setting, though. Building chips without silica or gold?).

Nevertheless, players would still need to command the drones to find and mine resources to supply the printer. Organics, oils, and bioplastics could probably be farmed. However, for minerals, I believe they would need iron, aluminum, copper, some gold and silver, lithium, and some rare earth metals - basically, the things necessary to build what we have today.

I have almost no knowledge of geology, so I'm trying to get an idea of the minimum number of different mines necessary to obtain these resources in enough quantity to build stuff that we have today (guns, vehicles, heavy machinery, computers, TV screens, etc). Assume that the first wave of colonists would have to supply and maintain only a colony of 1000 people or so. Would they still need as many mines and a complex supply chain as we have on today's earth? Are these essential minerals found togheter? Assuming that you are only trying to supply technology for 1000 people, would it be viable to mine these minerals from small veins that are not considered economically viable for today's standards?

  • $\begingroup$ I'm not sure exactly what kind of answer you're looking for. A colonizing mission would be pre-planed to every conceivable detail. Resource gathering and technological development would be part of that planning. Resource mapping of the planet would have been done before the plan was completed. Equipment with redundancy based on previous experience (or mean-time-between-failures planning). From a certain point of view, "what's the minimum resource list" is meaningless as that would be part of the plan and you didn't provide the geographical resource map of the planet. What's the real problem? $\endgroup$
    – JBH
    Commented Jun 17, 2023 at 4:29
  • $\begingroup$ BTW, keep in mind that you need all the resources we have today that's needed to build the stuff we build today. You can't have a smaller list without giving something up. Your settlers won't need the quantities that Earth creates, but you really can't build it significantly differently. Humanity already builds things to a reasonable degree of efficiency (competition has its advantages). The only real difference is in what order things are found so you can build from a small base - but that requires information you haven't provided - and it's only a matter of time, anyway. $\endgroup$
    – JBH
    Commented Jun 17, 2023 at 4:32
  • $\begingroup$ Finally, while this isn't a direct duplicate of Speedrun to the moon in one lifetime?, that question and it's answers would give you some good insight. $\endgroup$
    – JBH
    Commented Jun 17, 2023 at 4:42
  • $\begingroup$ The idea is that settlers are arriving in a distant start system after a 1000 years voyage. Their ship would orbit the target planet and use advanced sensors to map it for possible meneral rich areas, then send probes to check that out. Once mapping was done, drones would be sent to mine and build infrastructure. Only after that would people settle the planet. Of course, that is not what happens. There is a crash, the players fall on the planet without their survey data, and they now had to jumpstart the colony the hard way. $\endgroup$ Commented Jun 17, 2023 at 5:03
  • $\begingroup$ So, the ideia is that you already have the technological resources to A) smelt minerals, process chemicals, and build what you need, in the form of a sci-fi super efficient printer complex the size of a large complex; and B) you have the robotic workforce to build mine for resources and build new structures. So the question is, if I have these two components, how far do I need to mine, assuming I wanna grow slow and steady at first? Can I get most rare earth minerals I need from mining the earth 100, 200, 500 clicks from homebase? Or do mines need to be located the other side of the planet? $\endgroup$ Commented Jun 17, 2023 at 5:17

2 Answers 2


For high tech stuff you need a lot of mines.

A car needs 76 elements to work well. If you want a peak performing car, you need a fairly wide array of elements. A lot of them are gonna be fairly hard to find. Samarium for example is found in the fairly rare ore Monazite and other rare ores and is very useful in high heat permanent magnets.

There are six main types of mineral deposit and Monazite is a sedimentary phosphate rock generated by basins where the interaction between water and chemical precipitation concentrates the needed element to useful levels.

That said, you can get around that. Samarian is found in two to twenty parts per million of soil. and 2.3% in useful ores.

That means you just need to mine a million tons of soil to get two to twenty tons of Samarian. The same is true of many other rare elements.

The colony would probably be set up with several tiers of drones.

Some would be designed to run off very limited resources and use the common elements.

Oxygen - 46.1%
Silicon - 28.2%
Aluminium - 8.23%
Iron - 5.63%
Calcium - 4.15%
Sodium - 2.36%
Magnesium - 2.33%
Potassium - 2.09%
Titanium - 0.565%
Hydrogen - 0.140%

Unless something is radically different, these are probably gonna be common. Their abundance is similar to the stellar abundance, which results from nuclear physics in stars.

So, silicon is not likely to be an issue, and iron is pretty common. They can probably build cheap drones from common elements using iron and aluminium frames and silicon chips which can mine a huge amount of dirt for more rare elements.

Once you have rarer elements, from several million tons of dirt, you can then build more advanced goods and drones which use rare materials. Copper, gold, silver, lithium, and rare earth metals are likely to be in short supply in tier one drones, but possible in tier two drones, which might seek out better mines.

  • $\begingroup$ Thank you, that was an excellent answer! Would you mind if I ask you another question? Assuming that you just need to mantain the infrastructure for a very small arriving colony (1000 people or so), and you have fabricators and mining drones (so you just need resources), would you have to search far and wide for these rare minerals (like, setting up a mine on ther other side of the planet and creating a logistical chain), or are mineral deposits simply available on soil or on a single close mineral rich area enough to supply such a small colony? $\endgroup$ Commented Jun 17, 2023 at 0:42
  • $\begingroup$ This works great for a game setting. Just from the basic dirt you can build a few very basic drones. For more fancy stuff you need more and more rare elements. Depending on what you discover in reasonably exploitable quantities you get access to new things to build. $\endgroup$
    – quarague
    Commented Jun 17, 2023 at 8:19
  • 1
    $\begingroup$ If you wanted large cheap and efficient hauls, you need specialized mines, but if you just process a massive amount of material you can get whatever elements. We normally mine just efficient ores, but if you're willing to massively increase the cost common dirt can get most of your needs. In terms of a game, I would imagine perhaps the initial drones would do a lot of mining to set up a basic colony, but hostile alien wildlife and weather would prevent them from expanding more with the basic drones, and so there's a need for brave adventurers to set up new camps for rare stuff. $\endgroup$
    – Nepene Nep
    Commented Jun 17, 2023 at 9:26

As a supplement to the excellent answer by Nepene Nep:

I'd say, pick your landing-site well. Chose a coastal location with reliable cross-currents and decent sunshine - and hopefully a nearby freshwater river.

Seawater could very well be your first port of call.

Pressure-retarded osmosis can be used to produce energy from the osmotic potential difference between salt and fresh waters, and the seawater can be mined for rare elements.

A land-based, toes-in-the-ocean processing plant will use evaporation in large basins (made by drones using laser-sintered dirt) to collect gross-quantities of salt by evaporation. The various elements would then be recovered by a number of processes.

This would provide a kick-start for the acquisition of the rarer elements from the ocean, but fail to offer significant quantities of things like iron and silicon, these would require separate mines.

At later stages, it's worth noting that on Earth, we've significant quantities of useful stuff on the ocean floor, eg. polymetallic nodules containing, among other things, manganese, iron, nickel, and copper. But they're deep: 4,000 - 6,000 metres sometimes deeper, those are high-strength drones required to recover them, or nets on long drag-lines.

  • $\begingroup$ Once again thank you for the answer! So what I'm getting is, assuming that your colony is not trying to mine something to be economically viable (they just need resources to build new hab blocks, mantain their batteries and gear, and maybe build more drones at a small pace), and assuming that they survyed a region that is relatively mineral rich from space, they wouldn't have to create a global infrastructure with hundred of mines to supply a small 1000 people colony? $\endgroup$ Commented Jun 17, 2023 at 0:45
  • $\begingroup$ Probably not. They might need some specialist drones to build the infrastructure for the mining in the first place. There's a previous post regarding creation of infrastructure using dirt (regolith) that might be of interest. $\endgroup$ Commented Jun 17, 2023 at 0:50
  • $\begingroup$ Well, thanks again! $\endgroup$ Commented Jun 17, 2023 at 1:29
  • $\begingroup$ Thanks @jdunlop . Proof again I can't spell. $\endgroup$ Commented Jun 17, 2023 at 4:55

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