362 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
platinum, palladium, and gold, alongside industrially sig-
nificant metals such as iron and nickel. Additionally, carbo-
naceous asteroids are known for the presence of water and
volatile compounds, which can be utilized for sustaining
human presence and facilitating in-situ resource utilization
activities in space. The heterogeneous nature of asteroid
resources necessitates meticulous surveying and character-
ization efforts to discern optimal targets for extraction and
exploitation. Advanced remote sensing techniques, coupled
with in-situ prospecting missions, promise to unveil the
full spectrum of resources harbored within these celestial
bodies, paving the way for the development of sustainable
space-based economies and the realization of ambitious
space exploration objectives.
The imperative of space mining transcends mere extra-
terrestrial exploration, offering a strategic shift away from
terrestrial mining practices fraught with environmental
degradation, such as water and air pollution from toxic
chemical emissions. The development of highly efficient
space resource extraction techniques not only serves the exi-
gencies of space exploration but also portends benefits for
Earth, notably in addressing critical challenges like water
scarcity in the face of a burgeoning global population.
However, the efficacy of mining operations in the
microgravity environment of space hinges on a nuanced
understanding of fluid and particle behaviors, encompass-
ing phenomena like surface tension, buoyancy, convection,
and mixing (Raafat et al., 2013). In the absence of grav-
ity, these need to be re-evaluated and techniques need to
be customized for microgravity conditions in space. In this
project, we plan to study and compare (1) tumbling mills,
(2) stirred mills, (3) high-pressure grinding mills, and (4)
centrifugal mills in microgravity conditions and adapt them
for processing of magnetic and non-magnetic ore minerals
from extraterrestrial sources.
METHOD
In terrestrial ore processing, various ball milling techniques
are employed to comminute ore-bearing gangue, facilitating
the separation of valuable minerals. Extensive studies have
elucidated the efficiency and efficacy of these techniques
across diverse scenarios. However, the absence of gravity in
space necessitates a comprehensive reevaluation and cus-
tomization of these methodologies for microgravity condi-
tions. This project endeavors to scrutinize and compare the
performance of tumbling mills, stirred mills, high-pressure
grinding mills, and centrifugal mills under microgravity
conditions, tailored for processing magnetic and non-mag-
netic ore minerals from extraterrestrial sources.
Tumbling Mill
The tumbling mill consists of a rotating cylindrical shell
partially filled with grinding media such as balls, pebbles
or rods, that cascade and tumble inside the mill to grind
the material by impact, shear and abrasion. As shown in
Figures 1a and 1b, at lower speeds and with smooth lin-
ers, the grinding medium rolls down to the toe of the mill,
causing abrasive comminution and finer grinding with
Figure 1. a. Cross section of a tumbling ball mill showing the relationship between critical speed and the gravitational force
(Wills, B.A., &Finch, J.A., 2016) b. Cross section of a magnetic ball mill
platinum, palladium, and gold, alongside industrially sig-
nificant metals such as iron and nickel. Additionally, carbo-
naceous asteroids are known for the presence of water and
volatile compounds, which can be utilized for sustaining
human presence and facilitating in-situ resource utilization
activities in space. The heterogeneous nature of asteroid
resources necessitates meticulous surveying and character-
ization efforts to discern optimal targets for extraction and
exploitation. Advanced remote sensing techniques, coupled
with in-situ prospecting missions, promise to unveil the
full spectrum of resources harbored within these celestial
bodies, paving the way for the development of sustainable
space-based economies and the realization of ambitious
space exploration objectives.
The imperative of space mining transcends mere extra-
terrestrial exploration, offering a strategic shift away from
terrestrial mining practices fraught with environmental
degradation, such as water and air pollution from toxic
chemical emissions. The development of highly efficient
space resource extraction techniques not only serves the exi-
gencies of space exploration but also portends benefits for
Earth, notably in addressing critical challenges like water
scarcity in the face of a burgeoning global population.
However, the efficacy of mining operations in the
microgravity environment of space hinges on a nuanced
understanding of fluid and particle behaviors, encompass-
ing phenomena like surface tension, buoyancy, convection,
and mixing (Raafat et al., 2013). In the absence of grav-
ity, these need to be re-evaluated and techniques need to
be customized for microgravity conditions in space. In this
project, we plan to study and compare (1) tumbling mills,
(2) stirred mills, (3) high-pressure grinding mills, and (4)
centrifugal mills in microgravity conditions and adapt them
for processing of magnetic and non-magnetic ore minerals
from extraterrestrial sources.
METHOD
In terrestrial ore processing, various ball milling techniques
are employed to comminute ore-bearing gangue, facilitating
the separation of valuable minerals. Extensive studies have
elucidated the efficiency and efficacy of these techniques
across diverse scenarios. However, the absence of gravity in
space necessitates a comprehensive reevaluation and cus-
tomization of these methodologies for microgravity condi-
tions. This project endeavors to scrutinize and compare the
performance of tumbling mills, stirred mills, high-pressure
grinding mills, and centrifugal mills under microgravity
conditions, tailored for processing magnetic and non-mag-
netic ore minerals from extraterrestrial sources.
Tumbling Mill
The tumbling mill consists of a rotating cylindrical shell
partially filled with grinding media such as balls, pebbles
or rods, that cascade and tumble inside the mill to grind
the material by impact, shear and abrasion. As shown in
Figures 1a and 1b, at lower speeds and with smooth lin-
ers, the grinding medium rolls down to the toe of the mill,
causing abrasive comminution and finer grinding with
Figure 1. a. Cross section of a tumbling ball mill showing the relationship between critical speed and the gravitational force
(Wills, B.A., &Finch, J.A., 2016) b. Cross section of a magnetic ball mill
