332 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
inside the crater, the ice would be relatively stable, so over
time the ice would collect in these “cold traps” and be bur-
ied to some extent by meteoritic “gardening” and the blan-
keting by ejecta from subsequent nearby meteor impacts.
Gardening is the geologic process by which continuous
bombardment by micro-meteors pulverize and mix the
upper few meters of surface regolith. Until VIPER com-
pletes her mission, there is no ground-truth knowledge of
in-situ properties of lunar ice deposits.
There are many theories that postulate a range of values
for mechanical properties of icy regolith including com-
pressive strength, tensile strength, etc.11 Water content has
a significant influence on these properties, the greater the
water content the “stronger” the icy regolith. In addition to
water content the geologic formation of these deposits will
also influence their mechanical properties. Various ways in
which ice may be distributed within the regolith matrix are
illustrated in Figure 4.12
A wide variety of possible ice-regolith combinations
from individual ice grains mixed with regolith to ice-
cemented regolith, illustrate the potential challenges for
extracting water bearing ore. As with any mining project,
characterization of the ore body, quality and quantity of
water, ease of extraction and processing, etc., is critical for
establishing an efficient operation.
PROPERTIES OF LUNAR ICE:
Figure 5 developed by Chaplin13 illustrates the various
physical states water can take over a wide range of tem-
peratures and pressures, including those found on the sur-
face of the Moon, and on Earth at Standard Temperature
and Pressure (STP). At very low pressures, close to the
hard vacuum at the lunar surface, water may exist in solid
form below 200°K. Above 200°K at these low pressures,
water would exist as vapor, with no possible liquid phase.
Understanding and controlling temperature and pressure
of ice bearing ore on the Moon will be critical to processing
this resource.
PHYSICAL CONSIDERTATION
AFFECTING ORE EXTRACTION AND
PROCESSING:
Characterizing an ore body for a terrestrial mine is time con-
suming and requires extensive physical sampling and com-
puter simulations of the extent of the deposit. Uniquely,
on the Moon the extent of the deposit is bounded by the
dimensions of the cold trap (crater) containing the icy rego-
lith. The critical decision points for mine development are,
how rich in water is the regolith, and how difficult will it be
to extract and process the ore. Establishing water content
depends on the depth of the deposit being considered for
extraction. There are methods using lidar and radar that
can estimate water content for relatively shallow deposits,
say up to 10 meters. For deeper deposit traditional core
sampling may be appropriate.
The lunar and PSR environment will be a challenge for
engineers designing the equipment needed to extract and
transport the water bearing ore. Equipment currently being
Figure 3. VIPER9
Figure 4. Possible ice distribution within regolith
inside the crater, the ice would be relatively stable, so over
time the ice would collect in these “cold traps” and be bur-
ied to some extent by meteoritic “gardening” and the blan-
keting by ejecta from subsequent nearby meteor impacts.
Gardening is the geologic process by which continuous
bombardment by micro-meteors pulverize and mix the
upper few meters of surface regolith. Until VIPER com-
pletes her mission, there is no ground-truth knowledge of
in-situ properties of lunar ice deposits.
There are many theories that postulate a range of values
for mechanical properties of icy regolith including com-
pressive strength, tensile strength, etc.11 Water content has
a significant influence on these properties, the greater the
water content the “stronger” the icy regolith. In addition to
water content the geologic formation of these deposits will
also influence their mechanical properties. Various ways in
which ice may be distributed within the regolith matrix are
illustrated in Figure 4.12
A wide variety of possible ice-regolith combinations
from individual ice grains mixed with regolith to ice-
cemented regolith, illustrate the potential challenges for
extracting water bearing ore. As with any mining project,
characterization of the ore body, quality and quantity of
water, ease of extraction and processing, etc., is critical for
establishing an efficient operation.
PROPERTIES OF LUNAR ICE:
Figure 5 developed by Chaplin13 illustrates the various
physical states water can take over a wide range of tem-
peratures and pressures, including those found on the sur-
face of the Moon, and on Earth at Standard Temperature
and Pressure (STP). At very low pressures, close to the
hard vacuum at the lunar surface, water may exist in solid
form below 200°K. Above 200°K at these low pressures,
water would exist as vapor, with no possible liquid phase.
Understanding and controlling temperature and pressure
of ice bearing ore on the Moon will be critical to processing
this resource.
PHYSICAL CONSIDERTATION
AFFECTING ORE EXTRACTION AND
PROCESSING:
Characterizing an ore body for a terrestrial mine is time con-
suming and requires extensive physical sampling and com-
puter simulations of the extent of the deposit. Uniquely,
on the Moon the extent of the deposit is bounded by the
dimensions of the cold trap (crater) containing the icy rego-
lith. The critical decision points for mine development are,
how rich in water is the regolith, and how difficult will it be
to extract and process the ore. Establishing water content
depends on the depth of the deposit being considered for
extraction. There are methods using lidar and radar that
can estimate water content for relatively shallow deposits,
say up to 10 meters. For deeper deposit traditional core
sampling may be appropriate.
The lunar and PSR environment will be a challenge for
engineers designing the equipment needed to extract and
transport the water bearing ore. Equipment currently being
Figure 3. VIPER9
Figure 4. Possible ice distribution within regolith