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Biosustainable Mining: Unlocking Opportunities in Selective
Gangue Removal, Bio-Cementation and Carbon Sequestration
Using Microbial Processes
Dan Stigers, Karrie Radloff, Michaeline Albright, Coy Zimmermann,
Bianca Cruz, Tom Lankiewicz, Dayal Saran, Kent Sorenson
Allonnia, Boston, MA
ABSTRACT: Recent advances in our ability to manipulate microbiology open a new frontier for the mining
industry. We are utilizing natural microbial metabolites (our bio-solvents) to selectively solubilize gangue from
various concentrates and tailings, where we have selectively dissolved magnesium-containing minerals from
nickel sulfide concentrates, or alumina and silicates from iron concentrates. These bio-solvents can be recycled
by stripping out the solubilized impurities and reused, unlike inorganic acids which are irreversibly consumed.
Our technology can be used as a bolt-on process to treat a side stream of concentrate, thus improving grade
to positively impact downstream processes. By using microbes, Allonnia can agglomerate and add strength
to a wide range of mining materials via carbonate-producing biological reactions, and be applied to reinforce
stockpiles and increase tailings stability. Microbially mediated processes also have potential to sequester CO2.
INTRODUCTION
Our mission is to utilize known and novel biological pro-
cesses to tackle some of the world’s most pressing environ-
mental challenges. We identified several processes essential
to the mining industry that are naturally occurring at the
microscale in microbial communities across the globe and
have used this as both an inspiration and a starting point
for transforming how these processes can be done at scale
– to unlock untapped potential and to bring about more
environmentally responsible technologies. We have identi-
fied three areas within the mining industry where known
microbial processes play a key role: the solubilization of
target elements, the controlled agglomeration of particles
through the precipitation of carbonates, and the sequestra-
tion of CO2 to offset carbon emissions.
The natural weathering of silicate and other materi-
als by microbes present in the environment provides the
starting point for the development of unique bio-solvents
comprised of bacterial and/or fungal metabolites (Castro
et al. 2000 Jain and Sharma, 2004 Torres et al., 2019,
Li et al. 2019 Lamerand et al., 2020). The bio-solvents
have several distinct advantages over conventional mineral
acids such as sulfuric or hydrochloric acid (Dong et al.,
2022). First, in addition to lowering the pH and promoting
acidolysis, the bio-solvents provide ligands and chelators
that form strong complexes and can potentially improve
solubilization rate and extent by thermodynamically favor-
ing the reaction towards increased solubility. Second, the
bio-solvent can be produced via fermentation and poten-
tially recovered through less environmentally costly meth-
ods than conventional mineral acids. We are developing a
range of bio-solvents that can be tuned based on material
(e.g., ores, concentrates, tailings) and selective removal
needs (e.g., gangue or penalty elements) to act as targeted
Biosustainable Mining: Unlocking Opportunities in Selective
Gangue Removal, Bio-Cementation and Carbon Sequestration
Using Microbial Processes
Dan Stigers, Karrie Radloff, Michaeline Albright, Coy Zimmermann,
Bianca Cruz, Tom Lankiewicz, Dayal Saran, Kent Sorenson
Allonnia, Boston, MA
ABSTRACT: Recent advances in our ability to manipulate microbiology open a new frontier for the mining
industry. We are utilizing natural microbial metabolites (our bio-solvents) to selectively solubilize gangue from
various concentrates and tailings, where we have selectively dissolved magnesium-containing minerals from
nickel sulfide concentrates, or alumina and silicates from iron concentrates. These bio-solvents can be recycled
by stripping out the solubilized impurities and reused, unlike inorganic acids which are irreversibly consumed.
Our technology can be used as a bolt-on process to treat a side stream of concentrate, thus improving grade
to positively impact downstream processes. By using microbes, Allonnia can agglomerate and add strength
to a wide range of mining materials via carbonate-producing biological reactions, and be applied to reinforce
stockpiles and increase tailings stability. Microbially mediated processes also have potential to sequester CO2.
INTRODUCTION
Our mission is to utilize known and novel biological pro-
cesses to tackle some of the world’s most pressing environ-
mental challenges. We identified several processes essential
to the mining industry that are naturally occurring at the
microscale in microbial communities across the globe and
have used this as both an inspiration and a starting point
for transforming how these processes can be done at scale
– to unlock untapped potential and to bring about more
environmentally responsible technologies. We have identi-
fied three areas within the mining industry where known
microbial processes play a key role: the solubilization of
target elements, the controlled agglomeration of particles
through the precipitation of carbonates, and the sequestra-
tion of CO2 to offset carbon emissions.
The natural weathering of silicate and other materi-
als by microbes present in the environment provides the
starting point for the development of unique bio-solvents
comprised of bacterial and/or fungal metabolites (Castro
et al. 2000 Jain and Sharma, 2004 Torres et al., 2019,
Li et al. 2019 Lamerand et al., 2020). The bio-solvents
have several distinct advantages over conventional mineral
acids such as sulfuric or hydrochloric acid (Dong et al.,
2022). First, in addition to lowering the pH and promoting
acidolysis, the bio-solvents provide ligands and chelators
that form strong complexes and can potentially improve
solubilization rate and extent by thermodynamically favor-
ing the reaction towards increased solubility. Second, the
bio-solvent can be produced via fermentation and poten-
tially recovered through less environmentally costly meth-
ods than conventional mineral acids. We are developing a
range of bio-solvents that can be tuned based on material
(e.g., ores, concentrates, tailings) and selective removal
needs (e.g., gangue or penalty elements) to act as targeted