XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2477
INTRODUCTION
The concentrator of Caserones Lundin Mining is located at
4000 m above sea level, 160 km from the city of Copiapo in
Chile. The average ore grade is 0.45% copper and 0.015%
molybdenum. The concentrator throughput is over 4000
t/h. The flotation circuit have a conventional rougher stage
and two-cleaner stages with a scavenger. The cleaning stage
consists of a first cleaner with two self-aerated cell and the
second cleaner with two flotation columns in parallel and
produces a bulk concentrate about 30% copper and 1%
molybdenum. The rougher circuit has two rows of eight
cells of 300 m3 self-aerated in an arrange of 1-2-2-2-1 and
a regrinding circuit with two Vertimill 1250, Figure 1.
One of the biggest challenges was the increase in effec-
tive treatment of the SAG mill, which was achieved during
the year 2023, reaching values ver 4700 tph. However, this
change also generated an increase in particle size towards
flotation, directly impacting copper recovery. This impact
was something that had already been foreseen, which is
why, in parallel with the increase of grinding throughput,
work was also carried out at the laboratory level to select a
complementary frother to the MIBC that is currently used
in flotation that would help improve recovery in conditions
of higher P80 and when minerals with more complex min-
eralogy impact the stability of the froth. Due to this, an
industrial test was carried out in the concentrator plant with
the Oreprep T-100 reagent from Solvay, Figure 2, which
not only achieved better metallurgical results, but also has
the peculiarity of switching above pH values 10.5 from
its base chemistry, glycol to a lighter alcohol, which in the
case of Caserones is convenient because the Rougher flota-
tion is operated at pH 9 while the cleaner at pH 11. This
test is not only a worldwide innovation, but also comes to
solve the typical problems that occur when using glycol-
based frother, such as over frothing in the flotation circuit.
METHODOLOGY
The evaluation methodology of the Oreprep T-100 reagent
consisted of two parts: the laboratory-scale evaluation and
validation of the reagent and then its evaluation by adding
the Oreprep T-100 foamer to the rougher flotation of the
Caserones concentrator plant.
The laboratory tests were carried out at standard con-
ditions in a Denver D-6 cell, considering a P80 of 200
microns, a solid of 38%, pH 9, 14 g/t of primary collector,
6 g/t of MIBC, 20 g/t of diesel whose kinetics consider
the times of 1, 7, and 15 minutes. For the development
of the tests, it was used ore with an origin on phase 6 (a
complex ore is mostly inside this area in the open pit) con-
sidering two sectors, one with better metallurgical perfor-
mance (Mineral A) and another extreme with lower copper
recovery (Mineral B). Both minerals were analyzed, pre-
pared, and chemically analyzed for copper, molybdenum,
iron, oxidized and insoluble copper. In addition, they were
analyzed by optical microscopy to see their mineralogical
composition.
The industrial evaluation was carried out by analyzing
and comparing the operational results during the months
Figure 1. Flowsheet of flotation RCS circuit at Caserones Lundin Mining
INTRODUCTION
The concentrator of Caserones Lundin Mining is located at
4000 m above sea level, 160 km from the city of Copiapo in
Chile. The average ore grade is 0.45% copper and 0.015%
molybdenum. The concentrator throughput is over 4000
t/h. The flotation circuit have a conventional rougher stage
and two-cleaner stages with a scavenger. The cleaning stage
consists of a first cleaner with two self-aerated cell and the
second cleaner with two flotation columns in parallel and
produces a bulk concentrate about 30% copper and 1%
molybdenum. The rougher circuit has two rows of eight
cells of 300 m3 self-aerated in an arrange of 1-2-2-2-1 and
a regrinding circuit with two Vertimill 1250, Figure 1.
One of the biggest challenges was the increase in effec-
tive treatment of the SAG mill, which was achieved during
the year 2023, reaching values ver 4700 tph. However, this
change also generated an increase in particle size towards
flotation, directly impacting copper recovery. This impact
was something that had already been foreseen, which is
why, in parallel with the increase of grinding throughput,
work was also carried out at the laboratory level to select a
complementary frother to the MIBC that is currently used
in flotation that would help improve recovery in conditions
of higher P80 and when minerals with more complex min-
eralogy impact the stability of the froth. Due to this, an
industrial test was carried out in the concentrator plant with
the Oreprep T-100 reagent from Solvay, Figure 2, which
not only achieved better metallurgical results, but also has
the peculiarity of switching above pH values 10.5 from
its base chemistry, glycol to a lighter alcohol, which in the
case of Caserones is convenient because the Rougher flota-
tion is operated at pH 9 while the cleaner at pH 11. This
test is not only a worldwide innovation, but also comes to
solve the typical problems that occur when using glycol-
based frother, such as over frothing in the flotation circuit.
METHODOLOGY
The evaluation methodology of the Oreprep T-100 reagent
consisted of two parts: the laboratory-scale evaluation and
validation of the reagent and then its evaluation by adding
the Oreprep T-100 foamer to the rougher flotation of the
Caserones concentrator plant.
The laboratory tests were carried out at standard con-
ditions in a Denver D-6 cell, considering a P80 of 200
microns, a solid of 38%, pH 9, 14 g/t of primary collector,
6 g/t of MIBC, 20 g/t of diesel whose kinetics consider
the times of 1, 7, and 15 minutes. For the development
of the tests, it was used ore with an origin on phase 6 (a
complex ore is mostly inside this area in the open pit) con-
sidering two sectors, one with better metallurgical perfor-
mance (Mineral A) and another extreme with lower copper
recovery (Mineral B). Both minerals were analyzed, pre-
pared, and chemically analyzed for copper, molybdenum,
iron, oxidized and insoluble copper. In addition, they were
analyzed by optical microscopy to see their mineralogical
composition.
The industrial evaluation was carried out by analyzing
and comparing the operational results during the months
Figure 1. Flowsheet of flotation RCS circuit at Caserones Lundin Mining