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I was reading about Elon Musk believing space mining being unprofitable due to mining and transportation costs. Now I dont know about mining costs , but if Elon Musk says a person could go to Mars for less than 200,000 U$S in the future, that would be about,

U$S 3225 per kg considering an average person. I dont know if we can transfer so directly the costs for kg of person to the cost for kg of raw materials, but assuming we could, if we transfer these costs to the kg of gold, it's an increase of 7,5% in the cost of gold, but it would be Mars obtained gold. Wouldnt 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 may be someone can enlight this on possible mining costs in Mars, assuming gold it's found in some regular place of Mars surface.

Is making gold mining in Mars profitable truly unlikely?

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    $\begingroup$ 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. $\endgroup$ – uhoh Feb 23 '19 at 2:47
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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 required 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.

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  • $\begingroup$ +1 for pointing out that it's not simply a matter of picking up gold nuggets and putting them on a space ship home. $\endgroup$ – Schwern Feb 23 '19 at 19:31
  • $\begingroup$ I love how our answers here have shaken out: 1. No. 2. We really don't know. 3. We really, REALLY don't know 😎. $\endgroup$ – Chris B. Behrens Feb 23 '19 at 20:23
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    $\begingroup$ 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. $\endgroup$ – Ken Fabian Feb 23 '19 at 21:25
  • $\begingroup$ @KenFabian: It's a shame that the engineer of Goldfields Water Supply Scheme, that supplied water to Kalgoorlie, C. Y. O'Connor committed suicide after being ridiculed about the scheme, in the press & in parliament over a prolonged period. Trolls existed long before the internet eventuated. Kalgoorlie is still reliant on the 600 km water pipeline from Perth. There are aquifers in the greater Kalgoorlie region, but they are mostly saline. Some of them hyper saline - some up to 40 time saltier than sea water. Continued ... $\endgroup$ – Fred Feb 24 '19 at 7:59
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    $\begingroup$ 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/… $\endgroup$ – Cornelis Dec 20 '20 at 15:31
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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.

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  • $\begingroup$ Would we expect there to be any evidence, given how hard we've looked so far? $\endgroup$ – Chris B. Behrens Feb 23 '19 at 3:42
  • $\begingroup$ 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. $\endgroup$ – TheWolfEmperor Feb 23 '19 at 4:03
  • $\begingroup$ 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. $\endgroup$ – Chris B. Behrens Feb 23 '19 at 4:20
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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.

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  • $\begingroup$ 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/… $\endgroup$ – Ken Fabian Feb 23 '19 at 21:42
  • $\begingroup$ Oops - wrong link, was meant to be - space.stackexchange.com/questions/27431/… $\endgroup$ – Ken Fabian Feb 24 '19 at 2:31
  • $\begingroup$ 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. $\endgroup$ – Chris B. Behrens Feb 24 '19 at 3:51
  • $\begingroup$ 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. $\endgroup$ – Ken Fabian Feb 26 '19 at 22:50
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    $\begingroup$ 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. $\endgroup$ – Ken Fabian Feb 27 '19 at 22:07

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