Applying Mining Concepts to Accessing Asteroid Resources

Mark Sonter, Asteroid Enterprises Pty Ltd, Brisbane, [email protected]

ph +61 7 3297 7653,

and

‘The Asteroid Mining Group’: Al Globus, Steve Covey, Chris Cassell, & Jim Luebke; with Bryan Versteeg & James Wolff

Mining the Near-Earth Asteroids:

-- There are

very high-value resources

in space, awaiting the development of an

in-space market

; And the technology to get to them, and retrieve them, is available

now

… Images from William K Hartmann

Asteroid characterization:



What do they look like?



How big are they?



Why are we interested in them?



What ‘goodies’ do they contain?



How many are there?



What structure / fabric / strength?



How (pray tell) might we mine them??

Asteroid 951 Gaspra (18 km x 10 km x 9 km) - silicate

Asteroid 243 Ida (59 km x 23 km x 19 km) - silicate

253 Mathilde (66 km x 48 km x 44 km) - carbonaceous

Eros

433 Eros (33 km x 13 km) - silicate

Itokawa

with International Space Station to scale It’s a

rubble pile

with lots of void space:  = 1.95 g/cc Regolith (present even in micro-g!!) is gravel-size particles

Asteroids offer both Threat and Promise –



Threat

of impacts delivering regional or global disaster. 

Promise

of resources to support Humanity’s long-term prosperity and expansion into the Solar System.

 The technologies to tap asteroid resources will

also

enable the deflection of at least some of the Impact-Threat objects

-- It is likely that the Near Earth Asteroids will be major resource opportunities of the mid 21 st century -- Thus we should seek to develop these technologies, to meet the emerging in space markets…

Asteroid Resources

High and increasing discovery rate of NEAs Growing belief that NEAs contain easily extractable high-value products Accessing asteroid resources is

dependent on development of market(s) for mass-in-orbit

How to compare schemes for mining a NEA and returning the product to market??

Capex, payback time,

and

net present value

critical design drivers, in choice of

market, product, mission type, extraction process,

and

propulsion system target,

are

Asteroid structure and strength

 Asteroids retain deep regolith (except the smallest?)   Often heavily fractured or rubble piles Have significant void space (‘macroporosity’)   Many appear to contain H 2 O in clays or salts Many appear to contain kerogen-like material (!!)  Many appear to contain Ni-Fe and PGMs  Some may be extinct / dormant comet cores  The value of these commodity products

in space

, is

thousands of dollars per kilogram

Products from asteroid mining:

 Raw silicate, for use in space (ballast, shielding)  Water, & other volatiles, for use in space (propellant)  Ni-Fe metal, for use in space (construction)  PGMs, for return to Earth (catalyst for fuel cells)  Semiconductor metals, for use in space (solar arrays)

Water can be used for PROPELLANT for the RETURN TRIP

The in-space market for raw material is not yet a reality....

But all mass used in space and originating from Earth costs at present $10,000 per kg to launch products… , thus setting a rough lower limit on the potential value of these

Lots of new knowledge:

 New Targets (generated by search programs)  Images, Concepts and Understandings 

But mining (and processing) is difficult, even on Earth!

(we will come back to this, later--)

-- Of course, the vast majority of the little fellas have not yet been found… As opposed to the



1 km ones, where the discovery rate has leveled off because most

have

now been found…

There are literally millions undiscovered in the under 30 metre and under 10 metre size range…

Huge increase in potential targets:

NEAs PHAs Total #

 8800  1300 

300 m diam

 2700  500?



1 km diam

 850  150 Potentially Hazardous Asteroids: approach Earth orbit to < 7.5 x 10 6 km (0.05 AU) Apollos: Amors: Atens: Atiras:  4700  3300  700  10 ( Earth crossers, sma  1 AU) ( 1 AU < Perihelion < 1.3 AU) ( Earth crossers, sma < 1 AU) ( Orbit totally inside Earth’s) (1 AU = 150 x 10 6 km = radius of Earth’s orbit) -

as of March 2012

From Mike A’Hearn, P.I. Deep Impact:

   15% of NEAs have Jupiter Family Comet type orbits (and hence cometary in origin??) Comets are  50% H 2 O by mass Most ice is  1 to 3 thermal skin thicknesses deep (? say  10 m)  Comets have bulk density 0.5 g/cc and thus 75% empty space: highly porous!!

 Weak: tensile strength <100 Pa from SL9 (at km scale); < 10 kPa from Deep Impact (at metre scale)   Thermal conductivity very low Deep Impact excavated  surface of Comet Wild (!!) 5000 tonnes of ice from within 2 m of

Cryptocomet model:

Loose & fluffy ‘lag deposit’,

or

cinder

insulating the underlying icy matrix (?  1 metre)

Densified

underlying ice-clay kerogen layer of thickness  2 metres Deep porous low density ice-clay kerogen

matrix

How to mine this??

We could encounter a weakly bound rubble pile – or a fragment of one:

Large boulders, voids, ‘

macroporosity

’ at depth Grading finer to

gravel regolith at surface ?? Ices in voids??

How to mine this??

Impact development of megaregolith

          

Terrestrial

Project Development Path:

“Desktop” studies: what to look for, & where Open-literature and proprietary data reviews Reconnaissance of prospective target areas Identification of potential targets Field work identifies extended mineralization Drillout of prospect to define orebody Metallurgical testwork to confirm extractability Project conceptual planning / prefeasibility studies Bankable Costing & Feasibility Study (& EIS) Funding and Project Go-Ahead Construct and Commission

Mining Engineering and Economics

“Material is ore only if you can mine, process, transport and market it for a profit”.

Terrestrial Mine Project Planning

involves

choosing

between

competing mining & metallurgical extraction concepts

, to:      Minimize Capital Expenditure (Capex), Minimize operating cost (Opex), Consistent with desired Production Rate, and also Minimize payback time, and Minimize project risk

-and thereby Maximize Expectation Net Present Value So must it be also, in Space Mining…

Bankable Feasibility Study must develop:



A Mining Plan

, based on an 

Accurate orebody model

, and a 

Metallurgical Process Flowsheet

, based on 

Accurate understanding of the ore,

which 

optimises Recovery,

and 

minimizes Capex

,

Opex

, &

Payback Time

, and 

optimizes the Production Rate

, so as to

maximize the Expectation Net Present Value.

Choice of Mining Plan and Process is often surprisingly difficult--

Some cautionary tales from Oz mining scene --

Olympic Dam Cu-U-Au project

: very non-obvious mining and processing choices

Mulga Rocks U+ base metals project

: ditto ditto

Nolans Rare Earths project

: very challenging process development

Beverley U In-Situ Leach

: seriously compromised by lack of accurate orebody model…

The “Economic Imperative” for Asteroid Mining:

Maximize Expectation NPV implies   Minimize project risk  Simplest possible extraction, processing, and propulsion systems – KISS principle  Minimize CAPEX  single or double launch, unmanned;  Maximize returned payload fraction  including capture into Earth orbit minimize return  v  Minimize return  v  target’s orbit should be low eccentricity and earth grazing; use lunar flyby capture  Minimize payback time  minimum duration mission  target asteroid semi-major axis  1 AU;  Synodic period constraint  ‘single season’ mine mission

Asteroid Mining Project Economics will be driven by



MINER MASS and LAUNCH COST



SPECIFIC MASS THROUGHPUT OF MINER



MISSION DURATION and MASS RETURNED



DELTA-V for RETURN into Earth Orbit



POWER & PROPULSION SYSTEM parameters



VALUE PER KG DELIVERED TO LEO GEO or HEO

Mining Method Advantages Disadvantages

Surface reclaim with ‘snowblower’

(accepted)

robust process; easy to handle loose soil; easy to monitor Problems with anchoring & containment; surface will be desiccated.

Solar Bubble vaporizer

(rejected)

Simple, Collects volatiles only In-Situ Volatilization

(rejected)

simple concept; asteroid body gives containment.

Unacceptably high membrane tension; how to (a) seal (b) anchor?

needs low permeability; risks are loss of fluid; clogging; & blowout.

Explosive Disaggregation

(potential)

Downhole Jet Monitoring (rejected) Very rapid release of mass, short timeline.

Mechanically simple; Separates mining from processing task.

Capture of material is unsolved.

Need gas to transport cuttings to processor. blowout risk high.

Underground mining by mechanical ‘mole’

(accepted)

reduced anchoring & containment problems; physically robust Mechanically severe; hard to monitor; must move cuttings to surface plant

Mechanical miner – ‘SpaceMole’?

Must solve these basic tasks:



Anchoring (onto a micro-gravity body!)



Comminution



Ground control (even in micro-g)



Containment of product cuttings



Handling of cuttings thru Processor



Separation and storage of product(s)

Comparisons with Terrestrial Mining

Best comparisons are with  Remote, high grade, very high value, high margin, small throughput, exotic product operations….

see following slides:

Terrestrial Remote High Value Mines

 Klondike Goldrush, 1898  Ekati diamond mine, Canada (access by ice road, 10 weeks per year)  Namibia offshore diamond dredging (Skeleton Coast)  Artisanal goldminers in Brazil, PNG and elsewhere  Bulolo goldfields, New Guinea, 1930’s (more airfreight than

entire rest of world total

, to build 8 x 1500 tonne dredges)  Shinkolobwe , Belgian Congo, 1920’s; and Port Radium, Canada, 1930’s (Radium was $100,000 / gram!)  Nautilus Deep Sea Massive Sulphides (Manus Basin, PNG)

BHP-Billiton Ekati Diamond mine, NWT, Canada:

10 weeks ice road access per year

….

At the height of the Mt Kare gold rush in the highlands of Papua New Guinea, these villagers would

flag down passing helicopter taxis to fly them to the bank

…

Andamooka opal fields, South Australia

Bulolo Goldfields, 1930’s Read ‘Not a Poor Man’s Field’ by Waterhouse, Halstead Press

Notes from Terrestrial Mining (2)

There is a

vast

range of

orebody types & geometries, thus vast range of mining methods

:  Open pit (shallow or deep, soft or hard rock, strip mine, dredge, …)  Underground (room & pillar, Long-Hole Open Stoping, cut & fill, block cave)…  In Situ Leach...

Must understand your orebody and choose correct (and robust) method or risk project failure

Ore grade is measured in…

 Gold:  Uranium:  Pb, Ni, Cu: grams per tonne (ppm) kg per tonne (or lb/ton) % But in reality, mining engineers talk about ore grade in terms of --

$ per tonne So should we…

for example, see next:

Haul truck, Prominent Hill Copper Mine, 200 km NW of Woomera, South Australia: Cu grade = 2%; Au = 0.2 g/t Value of ore at recent Cu & Au price = $170 / tonne

PGMs or Water or Ni-Fe?

 Assume we have a target asteroid which contains

50 ppm PGMs

and

10% H 2

O and 10% Ni-Fe

:

 

PGMs value (on Earth)

H 2

 $4,000 / tonne of regolith ore

O or Ni-Fe value (in orbit)

 $1 x 10 6 / tonne of ore (replacing $10,000 / kg cost if launched from Earth)

Which product is more important??

-

Is this “ore” ?

Only if we can mine, process, transport, and sell the product, AT A PROFIT

…

Comparisons with Terrestrial (2)

Seabed Mining of Massive Metal Sulphides in Volcanic Black Smoker Vent chimneys Some interesting parallels with asteroid mining-- - very high value ore, multiple products - small multiple deposits, mineable sequentially - low mass throughput (down by factor of 50-100) - mobile, teleoperated equipt ‘terra nullius’ if outside national EEZ - no landowner ident & compensation issues!!

Exploring for

Seabed Massive Sulphides

offshore PNG (in active Black Smokers and extinct Black Smoker chimney strewnfields on seamounts)

Seabed Massive Sulphides

…

Metal grades can be +50%

Why Seabed Massive Sulphides --

 Lower discovery costs: exposed, easy sampling  Low cost / easy trial mining  Shorter project lead time: easy ore access (no shaft, decline, or open pit prestrip)  No landowner compensation costs  Cheaper beneficiation, easier metallurgy, less materials handling: all due to ultra-high grade  No ‘pit to port’ infrastructure: major Capex item in terrestrial mining

Seabed Massive Sulphides (2)

 Cheaper plant: build in shipyard, sail to site  FPSO vessel can even be

leased

: removes single biggest Capex item!

 Single plant can access several deposits sequentially, hence  Lower feasibility hurdle: access to multiple deposits plus plant mobility means not necessary to confirm full ‘mine life’ reserves  Much less waste & enviro impact due to low mass throughput: thanks to ultra-high grades

(adapted from presentation by Julian Malnic, Nautilus CEO, 2000)

Note the amazing parallels of Deep Sea Massive Sulphides Mining with our hypothesized NEA Mining….

Notes from terrestrial processing

 From

simple

(

gravity, magnetic, electrostatic separation

) to

highly complex

, including  Pyrometallurgical (smelters, fire refining etc)  Hydrometallurgical (leaching, solvent extraction)  Electrolytic  Vapour separation!! (Mond nickel process)

Terrestrial Processing (2)

Metallurgical

flowsheet: how to separate the product(s) from the waste - This is

more complex and difficult

if trying to extract multiple products: Solid / solid separation : density or electrostatic Solid / liquid sep’n: by dissolution / precip’n / filtering Solid / vapour sep’n: volatilization, eg Mond process (nb: vapour processes are

limited by low massflows)

Liquid / liquid: smelting, melt electrolysis etc

-- Must choose correctly or you may lose your project

Comparisons with Terrestrial (3)

 NEAs

are prolific

, with subset having low Δv   Many are very prospective for H 2 O, Ni-Fe

Very

valuable ore ($1x10 6 / tonne)  

Easy

extraction (??) Target return parcels  500 - 5,000 tonnes

Asteroid resource return missions will be analogous to short campaign or Trial Mining of very high value ores

So what will an Asteroid Miner look like?? – I don’t know, but:

 Design depends on target orebody ‘model’  Small, highly integrated, digger (plus processor?)  Assume solar powered (nuclear is out, politically)  Assume main products are raw silicate, H 2 O, and / or Ni-Fe delivered into LEO, GEO, or HEEO 

We await only development of market in orbit …

Ultimately, Remote Miners will process regolith In-Situ to produce propellant for return, But –

and this is very recent finding, from our own studies, & validated by the Keck Workshop:

For objects smaller than (say) 7 metres diameter, and in low-eccentricity earth-grazing orbits, it

now appears to be possible to return the entire body to High Elliptical Earth Orbit (HEEO),

using

Earth-origin propellant and high Isp electric propulsion (eg Hall Thrusters)….

This technology is no more demanding than a communications satellite….

What we are up to, near term:

Papers for ISDC and AIAA; Further development of concept(s):

Don’t Send the Astronauts to the Asteroid

Bring the Asteroid to the Astronauts

A radical alternative to the planned 2025 asteroid visit Al Globus, Chris Cassell , Jim Luebke, Mark Sonter, Bryan Versteeg, and James Wolff, ISDC 2012, Washington, DC

Asteroids to Astronauts

Our alternative is to

bring multiple small asteroids into High Earth Orbit (HEO)

where astronauts set up mining equipment on them. Requires:     Identification and characterization of candidate asteroids in terms of size, mass and rotation rate Vehicle to capture asteroid, despin and perturb asteroid orbits into Earth-orbit-intercept trajectory A thrust program Δv under a few hundred m/s, to enable lunar gravity assists to bring asteroid into HEO System to bring astronauts to HEO and maintain them   Asteroid mining hardware and procedures Markets for asteroidal materials

Why We Think This Works

Damon Landau, JPL, Keck Workshop Oct 2011:   Analyzed lunar assist return for 1991VG, 2006RH120, 2007UN12, and 2009BD Result   500 ton asteroid to HEO - assuming a density of 3 tons/m 3 ~ 5-6 m diameter 40 kW near-term solar electric propulsion (SEP) - 8 tons of Xenon fuel required.

 Falcon Heavy  $80-120 million/flight  14-16 tons payload

Sonter’s catcher net: friction surfaces (brake pads) on all joints to absorb rotational energy

Asteroid Retriever probe with Capture Bag extended

(from Asteroid Retrieval Feasibility, Brophy et al, being report of the JPL Keck Institute Asteroid Workshop, Oct 2010)

Comparison

Astronauts to Asteroid

Six months travel time No rapid return No resupply Fixed, short stay times Much larger Δv, new vehicles required One asteroid per mission Repeat visits to same asteroid very difficult Cannot supply asteroid materials markets beyond science Some contribution to planetary defense Single, monolithic system

Asteroid to Astronauts

Six days travel time Return in three days Resupply in three days Indefinite stay times Smaller Δv, Falcon Heavy and Dragon sufficient Potentially many asteroids per mission Repeat visits easy Potentially supply multiple asteroid materials markets Includes full planetary defense system (detection and deflection) Many nearly independent components of intrinsic value

The Key

• Use gravity assists to bring the Δv down to the 100s of m/s • Find candidates that will enter the Earth-Moon system in a few years • For Δv-inf < 0.8/1.5 km/sec use lunar assist into HEO • Assume • Asteroid density 3.3 tons/m 3 • Engine exhaust velocity 35 km/sec (solar electric)

Δv (m/sec)

100 200 300 100 200 300

Asteroid Size (m)

5 5 5 10 10 10

Propellant mass (tons)

1.2

2.4

3.4

9.4

18.9

28.3

So -- in summary:

 Physically this should not be too difficult The ‘bus’ design appears to be not much more difficult than a commsat – queries remain around design of grabber and processing 

We therefore seek to make contact with potential users of in space resources…



And with resource developers looking for new high-value markets and prospects

For queries, contact Mark Sonter, [email protected]