# Would gold mining on Mars be truly profitable?

I was reading about Elon Musk believing space mining being unprofitable due to mining and transportation costs. Now I don't know about mining costs, but if Elon Musk says a person could go to Mars for less than US\$200,000 in the future, that would be about, US\$ 3225 per kg considering an average person.

I don't know if we can directly transfer the costs for a kilogram of a person to the cost a kilogram of raw materials, but assuming we could, if we transfer these costs to a kilogram of gold, it's an increase of 7,5% in the cost of gold, but it would be gold from Mars. Wouldn't that increase interest in jewelry customers?

Moreover, in another interview he said the costs could drop even more to 100,000 dollars, possibly making the increase of gold price by transportation 3,25%.

Now could someone shed some light on this regarding possible mining costs for Mars, assuming gold it's found in some regular place of Mars' surface.

How unlikely would it be for mining gold on Mars to be truly profitable?

• Can you show the full quote and context behind your reference to something you feel that Elon Musk is said? Perhaps it's the mining cost for something rare like gold, and the transportation cost for something cheap and heavy iron. Remember you have to tranpsort all the mining equipment to Mars, and power it as well.
– uhoh
Feb 23 '19 at 2:47
• If you want a rich gold deposit, look under the Caloris basin on Mercury. There very well might be a layer of solid gold down there (albeit deep down.) And no atmosphere means you can do an interplanetary launch off a catapault. Aug 27 '21 at 0:33
• At the time of this question, and even now 2.5 years later, the demonstrated cost per kg to return something from Mars is: Infinity. What level of future tech should we presume when answering? Aug 27 '21 at 7:16

As others have stated in their answers, there is no evidence, so far, that there is gold on Mars. We can't say there is or there isn't gold on Mars, we just haven't found any yet. We also don't know if gold were to exist, if it occurs in concentrated deposits, amenable to mining, or whether it's disseminated.

Gold hasn't been the focus of the exploration of Mars because it's not important enough, ... yet. Geological resources for construction materials and energy are currently more important.

If gold were discovered and mined on Mars, one question that needs to be asked is, "what do you do with it?". Do you send it to Earth to be stored in a secure vault? Why?

Formation of Gold Deposits ... On Earth

There are three ways gold deposits are formed on Earth.

1. Circulating Ground Waters.
2. Gold bearing solutions expelled from magma as it cools, precipitating minerals as they move into surrounding cooler rocks.
3. High temperatures and high pressures in mountain building regions resulting in chemical reactions that change rocks to new mineral assemblages (metamorphism).

All these processes require ground water as a transporting medium to concentrate gold and minerals.

Despite the suggestion that Mars once had oceans. We know nothing of ancient ground waters on Mars.

Mining on Mars

Before successful mining can occur, mineral exploration must be undertaken to determine the size and richness of any gold deposit. Currently on Earth this requires the use of exploration drilling rigs to outline the extent of any deposit. Drilling samples will need to be taken and assayed for gold content. Getting the drilling and assaying equipment to Mars will be expensive. All the equipment might be needed to be sent to Mars in parts and assembled there.

If we assume gold is present on Mars and that the deposits are large enough & rich enough (contain a lot of gold) how do they get mined? The answer depends on the nature of the deposit:

1. Nuggets on or just below the surface.
2. Locked within rocks, near the surface and potentially amenable to open pit (surface mining) techniques.
3. Locked within rocks, but deep below the surface of the planet and only mineable by underground methods.

Nuggets could be scooped up from the surface but open pit or underground mines will require heavy mining equipment. How does the equipment get to Mars? Transported from Earth in parts and assembled on Mars, which is very expensive; or does it get made on Mars from locally sourced minerals and locally constructed factories. This will be expensive and take a lot of time to achieve.

With exploration and mining there will be the issue of energy needed to power all the equipment. Unless large areas of the planet are sacrificed to photovoltaic arrays nuclear electric generators will be needed.

I speculate that batteries will not sufficient to power the heavy equipment for prolonged periods. This then leaves the use of power cables from a nuclear generator to power the equipment.

All of this is getting complex and expensive.

Mining produces dust, which on Mars will be a safety and operational problem because of impeded visibility and the affect on the equipment, particularly bearings and any rotating equipment.

On Earth, water is used to suppress dust. This then begs the question, "will there be sufficient water to suppress dust and can it be sacrificed for such a purpose?".

If the gold is locked within rock, will drill and blast techniques be used to break up the rock, or will grinding methods be used (adapting techniques used by tunnel boring machines)?

If drill and blast methods are used will explosives be transported from Earth or will they be made on Mars? More complexity and expense.

One method that could be used, if conditions were suitable is in-situ leaching. This requires the deposit to be drilled in a regular pattern and a dissolving solution to be pumped down some holes to dissolve the gold and the solution to then be pumped up other holes and the enriched liquor to be treated to remove the gold.

One problem with this technique is there may be minerals other than gold that could be preferentially leached leaving the gold in place underground. If marcasite (a form of iron pyrite) is present it will be leached in preference to any gold that may be present.

Treatment of Gold Bearing Ore

Now, assuming gold on Mars can easily be delineated during exploration and the ore mined, how is the gold then extracted from the fragmented rock?

The two main methods would be via a processing plant such as a carbon in pulp (CIP) or carbon in leach (CIL). Both require the use of cyanide to dissolve the gold and carbon to absorb the dissolved gold.

A cheaper method, that takes longer to recover the gold is heap leaching. This requires the fragmented gold bearing ore to be deposited into long mounds and a gold dissolving liquor (cyanide based) to be continuously dripped or sprinkled on the heap. As the dissolving liquor removes gold from the heap, it is collected from the pond at the bottom of the heap and treated further.

Problems with using this method on Mars are the cold temperatures and the thinness of the atmosphere and its low pressure and the potential for any water based solution/liquor to simply evaporate. This might be mitigated by enclosing the heaps in warmed pressurized containment structures.

All this is expensive and would require trained personnel.

Irrespective of whether a CIP plant of a heap leach pad is used the gold would then need to be electroplated and turned into bars for transport. This would require the use of electricity during the electroplating process and a source of heat would be needed to melt the gold and pour it into bars.

All this is costly enough on Earth, on Mars it will be more expensive because everything will need to be transported there simply to get the gold off the planet.

• +1 for pointing out that it's not simply a matter of picking up gold nuggets and putting them on a space ship home. Feb 23 '19 at 19:31
• One of Earth's largest gold deposits - Kalgoolie, Australia - was not economically viable to exploit until a piped water supply was built. A sufficiency of water figures highly in both the geological formation of concentrated deposits and known, proven means to extract it at low cost. Feb 23 '19 at 21:25
• I think it all boils down to the composition of the body. If it's something akin to gold deposits in the crust on Earth, it's a (WAY) no-go. If it's something more like rake mining...then it's still marginal without infrastructure. But once that infrastructure is complete, it becomes something like 1849...at least until the prices of the materials reach a much lower commodity equilibrium. Feb 27 '19 at 19:18
• A few days after your extensive answer a study was published that suggests a planet-wide groundwater system on Mars ! esa.int/Science_Exploration/Space_Science/Mars_Express/… Dec 20 '20 at 15:31

There hasn't been any evidence of gold on Mars. The articles available online have been of a speculative nature at best. As of this time, the only gold located on the surface of Mars that NASA is currently aware of is the gold finish on the body of the Mars Rovers.

This quote is from NASA.gov

•Preventing heat escape through gold paint

To help prevent heat from escaping out of the rover body and cold air from coming inside during landing operations, the outside of the rover body is painted with a gold coating. Using the same technique that many jewelers use, engineers lightly "sputter" or spray on the gold metal. The gold coating helps reduce energy that is radiated (energy spread outward) from the rover body.

The highly reflective gold finish effectively isolates the rover body from emitting heat energy out to the cold, sky temperature. This technique is similar to that used in a thermos bottle, where the reflective coating on the inner vacuum bottle helps keep coffee hot by minimizing radiation heat transfer across the bottle.

• Would we expect there to be any evidence, given how hard we've looked so far? Feb 23 '19 at 3:42
• I should rather hope so if people are going to spend their money on it. I'm the first person to get behind the space program and Elon Musk but not on a whim. Feb 23 '19 at 4:03
• I'm not saying that there is gold, but I am saying that we don't know, and in particular that if it were there, we wouldn't know about it from the exploration we've done. My answer below is even more pragmatic. Feb 23 '19 at 4:20
• @TheWolfEmperor - There will be Gold - it is virtually impossible that there not be some, if only from nickel-iron meteor impacts. At concentrations that are worth mining if it were on Earth seems possible. But even the best gold deposits on Earth would not be commercially viable to mine on Mars - Earth is the only market that is buying. In-situ mining and use is a different thing - it doesn't compete against resource costs on Earth, it competes against transport costs from Earth. Aug 26 '21 at 22:48

The information to answer this question does not yet exist. Heavy elements like gold exist in the crust of a planet somewhat idiosyncratically, that is, it's not something that you can project based on how it is on Earth. One of the reasons to look optimistically towards asteroid mining, for example, is that we expect that we may be looking at something more akin to the mantle or core of the Earth - it's not inconceivable that, rather than an admixture of elements like the crust, we might find an asteroid composed entirely - ENTIRELY - of gold. Or Platinum, or any other number of rare earth minerals.

What we know for sure about Mars is that its planetary formation is different than Earth's. We know that the composition of the core and mantle are different. It's possible that its formation resulted in tremendous extrusion of gold into the crust... Also, not at all. If it's plentiful, we have no idea if what logistics and mining techniques work effectively to extract it. If we knew that, we still don't have effective transport logistics to get it to market. If we get it to market, we don't know the market effects of the change in supply.

Honestly, we have better information about whether there's life on Mars. We're essentially asking these questions just after Columbus landed in the new world. But these are definitely questions worth asking, and answering.

• Between "not inconceivable" and what is known about asteroid formation, is there any real expectation we could find lumps of pure elemental metals? As far as I know every metallic meteorite sample is Nickel-Iron alloy - and the platinum and other precious metals are mixed in at low concentrations, ie very difficult to extract. space.stackexchange.com/questions/27329/… Feb 23 '19 at 21:42
• Oops - wrong link, was meant to be - space.stackexchange.com/questions/27431/… Feb 24 '19 at 2:31
• There's not enough to know, yet - APS 1 and 2 are proposals to get that question answered. But they meet thing is that asteroid are not (only) crust fragments, so it's at least possible that a hunk of one could be the spot in the mantle or the core where all the gold had pooled. The closer you get to the core, the less mixed you can expect the elements to be. Feb 24 '19 at 3:51
• Chris, I don't think it works like that - my understanding of asteroid formation is these elements mix and disperse within molten nickel-iron rather than separate. It is still worthwhile exploring, without expectations -and examining and sampling to see if theory is confirmed, or to see if there are real surprises. Feb 26 '19 at 22:50
• At over 100ppm of platinum group metal in some meteorites, that would be very exciting - if it were placer deposits (granules of pure platinum in silt) on Earth. Mixed in nickel-iron alloy the difficulties with extraction and refining are serious impediments, so not so exciting as it sounds at first glance. Separating the palladium, rhodium etc from the mix of platinum group metals would add another refining difficulty. Yes, we may get surprises by exploring and sampling, but I do have serious doubts about the mining opportunities for precious metals. Feb 27 '19 at 22:07

The OP claims (I can't check the calculation) that if the cost of per kg of payload to Mars is US\$3225, then it is only 7.5% more than the price of gold on Earth (at least, how I understand his reasoning). Then he concluded that, if Mr Musk can divide SpaceX cost per kg of payload by a factor 2, the delta of cost vs price of gold is also divided by 2 (3.25%). Which I believe is wrong, since if cost is marginally greater than price, dividing the cost by 2 makes the product very attractive. Furthermore, this question is mixing several aspects, to begin with, cost and price (cost to take one person to Mars compared to price of one kg of gold on Earth). Assume that I have set-up the first shop on Mars and I can sell water and gold. I am pretty sure that I can sell a liter of water at many times the price of a kg of gold, even if water and gold are equally plentiful on Mars. This is because price is also a function of demand. Assuming that Musk is talking about the COST for SpaceX to take one person to Mars (one way trip at US\$200,000 ). To convert that into a cost per kg of payload, we have to know how much water and food is needed for the journey. If it is 10 kg/day/person, then for an average journey of 200 days, we need 2000 kg of food & water (for a one way trip, assuming that existing facilities for that person to survive on Mars). Transportation of humans is not the same as transportation of coal. The quoted cost is surprisingly low.

Finally, as many have remarked, the cost of transportation to Mars is a very small part of the final cost to have the product available on Earth markets.

In engineering as well as in business, a common pitfall is to compare apples with pears.

Quite apart from the question whether there is gold in mineable quantities and deposits on Mars, you have to ask yourself what term are you thinking of.

Short term, as others have stated, it's simply not economical. Mid term, as the Martian population grows and starts to develop an industrial base, mining operations for other things and factories start to appear. These will make and produce more and more of the components needed to build the mining equipment that could be used to extract gold from whatever deposits may exist.

Long term, this will merge into a Martian economy that has itself a need for that gold. THAT's where it will become profitable as we now have a locally produced commodity that competes with an imported commodity that needs to be transported to Mars at great cost. Things like the production of advanced electronics on Mars will require gold for example, and if that gold can be sourced on Mars at a reasonable expense (using the same or similar equipment that would be used for other mining and construction work) that'd make it cheaper than sending it over on a rocket ship.

Of course there's also the option of mining it in the asteroid belt, which would also be at first very expensive but can in time become self supporting and makes the delivery of the goods to both Mars and Earth a lot cheaper than launching it from one planet's surface to the other.

Others have given good technical answers, but I would like to add an interesting commercial point: You don't need to bring the gold back to Earth.

See the figure below, but something between half and a third of the gold demand is not for actual use on Earth, but rather as a financial asset.

Demand for gold worldwide from 1st quarter of 2016 to 1st quarter of 2021, by purpose. Source

For investment and central banking purposes, gold being safely stored in Mars is likely even better than here on Earth, as long as you can host audits and provide other proof that such gold exists to the stated amount, and that can be brought to Earth if needed. Maybe a small amount if it could be brought to Earth every quarter such that a small adjustment or withdrawal could be compensated physically on a non-prohibitively high cost. Of course, this assumes that regular manned travel between Earth and Mars was a thing, which is not the case as of today, and maybe won't be for decades to come.

Thus, if a gold mine is ever found on Mars, and if it can be mined at a feasible cost, that is, if the problem is not transporting equipment and people there in the first place, then I'd pretty much say it might be a very good business.

• I dont think that financial asset value would be the same if it's on Mars. Aug 30 '21 at 18:19
• @Pablo If a company launched a mars-gold ETF, and spent part of the fees on arbitrage and on those small transports, they could stabilize the price of the financial derivative on pair with the value of the asset. Thus making the gold on mars nearly as valuable as the gold on Earth, for as long as the demand for gold as an investment is large enough compared to other demands such as jewelry and tech. Aug 30 '21 at 19:24