631
Treatment of Mining Acid Effluents by Reverse Osmosis
Jacob Croall, Wilder Sanchez, Jonathan Bishop
Newmont Corporation
ABSTRACT: This innovative work demonstrates that mining acid effluents can be treated directly through
Reverse Osmosis (RO) membranes while achieving compliance with the highest national and international
water quality standards.
The need to develop treatment processes for acidic waters arises from the fact that the currently existing tech-
nological options to reduce sulfates (SO4) in this type of water are limited. Mining effluents can have several
thousand milligrams per liter (mg/L) of sulfates, which need to be treated and reduced to a range between
250–1000 mg/L so that they can be safely discharged into the environment.
The methodology used to demonstrate the viability of this process included the installation of a pilot plant at
the Newmont Yanacocha (located in Peru) mining unit. This unit operated at a capacity of 2 m3/h for two years.
Mine acid effluents were directly treated through RO membranes, and managed to maintain continual opera-
tion without scaling or fouling resulting in high treatment efficiency.
INTRODUCTION
Newmont is a gold mining company, with more than 100
years of history in the mining industry and was founded in
1921. Newmont is a leader in gold production worldwide,
and also produces copper, silver, zinc and lead. Newmont
is currently operating in four regions with 12 operations
located in eight countries.
Newmont is an industry leader in value creation,
supported by solid safety standards, social environmental
practices and internal governance. Newmont has a quali-
fied technical team that seeks to innovate and develop new
technologies in order to optimize operational processes in
the production circuit.
The water treatment process is carried out during the
operational stage of production and continues during the
closing stage of operations. Currently all Newmont sites,
which are mentioned in Table 1, have water treatment
processes for internal use and or to discharge water to the
environment.
Sulfate is one of the parameters that represents a chal-
lenge in water treatment. Sulfates are normally produced
when the generation of acid occurs due to the presence
of sulfur sulfur is associated with some minerals and
its oxidation occurs when interacting with oxygen or
another oxidizing agents such as Fe3+. The concentrations
of sulfates in mine water discharges can be much greater
than 1,000 mg/L, in some cases with concentrations of
100,000 mg/L. High concentrations of sulfates need to be
treated and reduced to safe concentrations, which depend-
ing on their use downstream of the mine operation, is nor-
mally in a range between [250–1,000] mg/L. As referenced
and in accordance to Peruvian regulations, mine water dis-
charge is required to have sulfate concentrations less than
1,000 mg/L (ECA 3 -D1 and D2) for use in agriculture
and livestock. Sulfate concentrations are required to be less
Treatment of Mining Acid Effluents by Reverse Osmosis
Jacob Croall, Wilder Sanchez, Jonathan Bishop
Newmont Corporation
ABSTRACT: This innovative work demonstrates that mining acid effluents can be treated directly through
Reverse Osmosis (RO) membranes while achieving compliance with the highest national and international
water quality standards.
The need to develop treatment processes for acidic waters arises from the fact that the currently existing tech-
nological options to reduce sulfates (SO4) in this type of water are limited. Mining effluents can have several
thousand milligrams per liter (mg/L) of sulfates, which need to be treated and reduced to a range between
250–1000 mg/L so that they can be safely discharged into the environment.
The methodology used to demonstrate the viability of this process included the installation of a pilot plant at
the Newmont Yanacocha (located in Peru) mining unit. This unit operated at a capacity of 2 m3/h for two years.
Mine acid effluents were directly treated through RO membranes, and managed to maintain continual opera-
tion without scaling or fouling resulting in high treatment efficiency.
INTRODUCTION
Newmont is a gold mining company, with more than 100
years of history in the mining industry and was founded in
1921. Newmont is a leader in gold production worldwide,
and also produces copper, silver, zinc and lead. Newmont
is currently operating in four regions with 12 operations
located in eight countries.
Newmont is an industry leader in value creation,
supported by solid safety standards, social environmental
practices and internal governance. Newmont has a quali-
fied technical team that seeks to innovate and develop new
technologies in order to optimize operational processes in
the production circuit.
The water treatment process is carried out during the
operational stage of production and continues during the
closing stage of operations. Currently all Newmont sites,
which are mentioned in Table 1, have water treatment
processes for internal use and or to discharge water to the
environment.
Sulfate is one of the parameters that represents a chal-
lenge in water treatment. Sulfates are normally produced
when the generation of acid occurs due to the presence
of sulfur sulfur is associated with some minerals and
its oxidation occurs when interacting with oxygen or
another oxidizing agents such as Fe3+. The concentrations
of sulfates in mine water discharges can be much greater
than 1,000 mg/L, in some cases with concentrations of
100,000 mg/L. High concentrations of sulfates need to be
treated and reduced to safe concentrations, which depend-
ing on their use downstream of the mine operation, is nor-
mally in a range between [250–1,000] mg/L. As referenced
and in accordance to Peruvian regulations, mine water dis-
charge is required to have sulfate concentrations less than
1,000 mg/L (ECA 3 -D1 and D2) for use in agriculture
and livestock. Sulfate concentrations are required to be less