Applying Mining Concepts to Accessing Asteroid Resources

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Applying Mining Concepts to Accessing Asteroid
Resources

• Mark Sonter, Asteroid Enterprises Pty Ltd,
  Brisbane,
• sontermj_at_tpg.com.au ph 61 7 3297 7653,
• and
• The Asteroid Mining Group
• Al Globus, Steve Covey, Chris Cassell, Jim
  Luebke with Bryan Versteeg James Wolff

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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
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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??

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Asteroid 951 Gaspra (18 km x 10 km x 9 km) -
silicate
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Asteroid 243 Ida (59 km x 23 km x 19 km) -
silicate
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253 Mathilde (66 km x 48 km x 44 km) -
carbonaceous
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Eros
433 Eros (33 km x 13 km) - silicate
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Itokawa with International Space Station to
scale Its a rubble pile with lots of void space
? 1.95 g/cc Regolith (present even in
micro-g!!) is gravel-size particles
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Asteroids offer both Threat and Promise

• Threat of impacts delivering regional or global
  disaster.
• Promise of resources to support Humanitys
  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
  21st century
• -- Thus we should seek to develop these
  technologies, to meet the emerging in-space
  markets

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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 are
  critical design drivers, in choice of target,
  market, product, mission type, extraction
  process, and propulsion system

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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 H2O 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

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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,
  thus setting a rough lower limit on the potential
  value of these products

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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--)

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-- 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
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There are literally millions undiscovered in the
under 30 metre and under 10 metre size range
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Huge increase in potential targets
Total ? 300 m diam ? 1 km diam
NEAs ? 8800 ? 2700 ? 850
PHAs ? 1300 ? 500? ? 150
Potentially Hazardous Asteroids approach Earth
orbit to lt 7.5 x 106 km (0.05 AU)
Apollos ? 4700 (Earth crossers, sma ? 1
AU) Amors ? 3300 (1 AU lt Perihelion lt 1.3 AU)
Atens ? 700 (Earth crossers, sma lt 1
AU) Atiras ? 10 (Orbit totally inside
Earths) (1 AU 150 x 106 km radius of
Earths orbit) - as of March 2012
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From Mike AHearn, P.I. Deep Impact

• 15 of NEAs have Jupiter Family Comet type orbits
  (and hence cometary in origin??)
• Comets are ? 50 H2O 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 lt100 Pa from SL9 (at km
  scale)
• lt 10 kPa from Deep Impact (at metre scale)
• Thermal conductivity very low
• Deep Impact excavated ? 5000 tonnes of ice from
  within 2 m of surface of Comet Wild (!!)

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Cryptocomet model
Loose fluffy or cinder lag deposit,
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??
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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??
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Impact development of megaregolith
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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

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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

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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.

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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

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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 ? minimize
  return ?v including capture into Earth orbit
• Minimize return ?v ? targets 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

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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

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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 Unacceptably high membrane tension how to (a) seal (b) anchor?
In-Situ Volatilization (rejected) simple concept asteroid body gives containment. needs low permeability risks are loss of fluid clogging blowout.
Explosive Disaggregation (potential) Very rapid release of mass, short timeline. Capture of material is unsolved.
Downhole Jet Monitoring (rejected) Mechanically simple Separates mining from processing task. 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
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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)

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Comparisons with Terrestrial Mining

• Best comparisons are with
• Remote, high grade, very high value, high margin,
  small throughput, exotic product operations.
• see following slides

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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, 1930s (more
  airfreight than entire rest of world total, to
  build 8 x 1500 tonne dredges)
• Shinkolobwe, Belgian Congo, 1920s and Port
  Radium, Canada, 1930s (Radium was 100,000 /
  gram!)
• Nautilus Deep Sea Massive Sulphides (Manus Basin,
  PNG)

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BHP-Billiton Ekati Diamond mine, NWT, Canada 10
weeks ice road access per year.
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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
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Andamooka opal fields, South Australia
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Bulolo Goldfields, 1930s
Read Not a Poor Mans Field by Waterhouse,
Halstead Press
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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

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Ore grade is measured in

• Gold grams per tonne (ppm)
• Uranium kg per tonne (or lb/ton)
• Pb, Ni, Cu
• But in reality, mining engineers talk about ore
  grade in terms of -- per tonne
• So should we for example, see next

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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
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PGMs or Water or Ni-Fe?

• Assume we have a target asteroid which contains
• 50 ppm PGMs and 10 H2O and 10 Ni-Fe
• PGMs value (on Earth) ? 4,000 / tonne of
  regolith ore
• H2O or Ni-Fe value (in orbit) ? 1 x 106 / 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

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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!!

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Seabed Massive Sulphides
Metal grades can be 50
Exploring for Seabed Massive Sulphides offshore
PNG (in active Black Smokers and extinct Black
Smoker chimney strewnfields on seamounts)
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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

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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)

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

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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 sepn by dissolution / precipn /
  filtering
• Solid / vapour sepn 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

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Comparisons with Terrestrial (3)

• NEAs are prolific, with subset having low ?v
• Many are very prospective for H2O, Ni-Fe
• Very valuable ore (1x106 / 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

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So what will an Asteroid Miner look like?? I
dont 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, H2O, and /
  or Ni-Fe delivered into LEO, GEO, or HEEO
• We await only development of market in orbit

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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.

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What we are up to, near term Papers for ISDC
and AIAA Further development of concept(s)
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Bring the Asteroid to the Astronauts
Dont Send the Astronauts to the Asteroid
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

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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 ?v 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

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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/m3 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

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Sonters catcher net friction surfaces (brake
pads) on all joints to absorb rotational energy
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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)
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Comparison
Astronauts to Asteroid Asteroid to Astronauts
Six months travel time Six days travel time
No rapid return Return in three days
No resupply Resupply in three days
Fixed, short stay times Indefinite stay times
Much larger ?v, new vehicles required Smaller ?v, Falcon Heavy and Dragon sufficient
One asteroid per mission Potentially many asteroids per mission
Repeat visits to same asteroid very difficult Repeat visits easy
Cannot supply asteroid materials markets beyond science Potentially supply multiple asteroid materials markets
Some contribution to planetary defense Includes full planetary defense system (detection and deflection)
Single, monolithic system Many nearly independent components of intrinsic value
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The Key

• Use gravity assists to bring the ?v down to the
  100s of m/s
• Find candidates that will enter the Earth-Moon
  system in a few years
• For ?v-inf lt 0.8/1.5 km/sec use lunar assist
  into HEO
• Assume
• Asteroid density 3.3 tons/m3
• Engine exhaust velocity 35 km/sec (solar
  electric)

?v (m/sec) Asteroid Size (m) Propellant mass (tons)
100 5 1.2
200 5 2.4
300 5 3.4
100 10 9.4
200 10 18.9
300 10 28.3
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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

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For queries, contact Mark Sonter,
sontermj_at_tpg.com.au