3
present within each sample. The most abundant bacterial
genus in each sample is shown in Figure 2. The inoculum
sample has the most diverse population of bacteria present.
The most abundant microbe in the raffinate and treated raf-
finate samples was Acidiphilium sp. Further, Sulfobacillus
sp. was not present in either of the raffinate samples, while
Acidithiobacillus sp. was not present in the treated raffinate
sample. The lack of a diverse bacteria consortia can have
a negative impact on the efficiency of the leaching as the
oxidant is not regenerated within the system.
Reactor Tests
For the tests operated with inoculum, after 78 days of leach-
ing, 79% copper extraction was obtained for the catalyzed
reactor test compared to 30% observed in the control test,
an increase of 2.6x as shown in Figure 3. The overall extrac-
tion was lower in the tests with mine raffinate (51% in the
catalyzed compared to 26% in the control however, the
uplift factor was still significant (1.9x) as shown in Figure 4.
Due to the significant difference in initial ferric concen-
trations between the tests using inoculum (2 g/L) compared
to the tests using synthetic raffinate (0.3 g /L), additional
tests were run using the treated raffinate with supplemental
iron (2 g/L) to ensure sufficient oxidant availability.
Tests with ferric supplemented raffinate performed
similarly to tests using the original treated mine site raf-
finate, indicating that the amount of initial oxidant pres-
ent did not affect copper leach extraction. Results for these
tests yielded copper extractions of 56% in the presence
of Jetti’s technology compared to 22% in the control as
shown in Figure 5. These results are within ±5% of the syn-
thetic raffinate tests without supplemental iron and can be
Figure 2. Distribution of microbial genus for mine raffinate,
treated mine raffinate, and inoculum
Figure 3. Effect of catalyst addition on reactor tests operated
with inoculum
Figure 4. Effect of catalyst addition on reactor tests operated
with treated raffinate
Figure 5. Effect of catalyst addition on reactor tests operated
with treated raffinate with added iron
present within each sample. The most abundant bacterial
genus in each sample is shown in Figure 2. The inoculum
sample has the most diverse population of bacteria present.
The most abundant microbe in the raffinate and treated raf-
finate samples was Acidiphilium sp. Further, Sulfobacillus
sp. was not present in either of the raffinate samples, while
Acidithiobacillus sp. was not present in the treated raffinate
sample. The lack of a diverse bacteria consortia can have
a negative impact on the efficiency of the leaching as the
oxidant is not regenerated within the system.
Reactor Tests
For the tests operated with inoculum, after 78 days of leach-
ing, 79% copper extraction was obtained for the catalyzed
reactor test compared to 30% observed in the control test,
an increase of 2.6x as shown in Figure 3. The overall extrac-
tion was lower in the tests with mine raffinate (51% in the
catalyzed compared to 26% in the control however, the
uplift factor was still significant (1.9x) as shown in Figure 4.
Due to the significant difference in initial ferric concen-
trations between the tests using inoculum (2 g/L) compared
to the tests using synthetic raffinate (0.3 g /L), additional
tests were run using the treated raffinate with supplemental
iron (2 g/L) to ensure sufficient oxidant availability.
Tests with ferric supplemented raffinate performed
similarly to tests using the original treated mine site raf-
finate, indicating that the amount of initial oxidant pres-
ent did not affect copper leach extraction. Results for these
tests yielded copper extractions of 56% in the presence
of Jetti’s technology compared to 22% in the control as
shown in Figure 5. These results are within ±5% of the syn-
thetic raffinate tests without supplemental iron and can be
Figure 2. Distribution of microbial genus for mine raffinate,
treated mine raffinate, and inoculum
Figure 3. Effect of catalyst addition on reactor tests operated
with inoculum
Figure 4. Effect of catalyst addition on reactor tests operated
with treated raffinate
Figure 5. Effect of catalyst addition on reactor tests operated
with treated raffinate with added iron