3451
Saving Water and Tailing Dam Space for Medium Size Mines—
A Case Study Using Centrifuge Technology to Recover Process
Water from Mine Tailings
Eric Gentis, Terry Ostrum, Stephen Benyo
Flottweg Separation Technology, Inc., Independence, KY
ABSTRACT: Traditionally, tailings dams or a chamber filter (plate-and-frame) presses are used to dewater
tailings. This solution requires significant capital investment and infrastructure. Dams do not recover much
process water, and presses are expensive and labor-intensive and neither are portable.
A reliable, cost-effective alternative is explored here. This paper reviews the results of a month-long trial of a pilot
plant using a decanter centrifuge that is specifically designed to withstand the rigors of a mining application.
INTRODUCTION AND OVERVIEW
The mining customer in this case study already owns several
Flottwe.g., Z92 (920mm bowl diameter) decanter centri-
fuges operating successfully (24/7) at their main processing
plant, dewatering their tailings and recovering most of their
(very) expensive process water.
They wished to run a smaller pilot unit at a different,
more remote location where they operate another process
plant, to check whether the conditions there are also suit-
able to invest in another battery of Z92s for this 2nd opera-
tion. They are rapidly depleting their current tailings dam
space at this site and have a very significant water cost due
to their location in central Mexico’s arid region.
Flottwe.g., provided a suitably wear-protected Z5E
mining decanter centrifuge (530mm bowl diameter) to run
as pilot for a month. This size unit can effectively mimic the
large unit operations and is regularly used for this kind of
scaleup predictability pilot in mining applications.
Operation of the pilot centrifuge was 24/7 during the
pilot period. Regular sampling of the input feed material,
the output solids and output liquid (centrate) was per-
formed by trained and well-qualified operations staff on
a regular basis throughout the pilot period. These samples
were analyzed for their solids &moisture contents on site
in the Flottwe.g., portable laboratory, immediately after
capture.
After installation and start-up, 117 separate tests were
taken over 12 days. These 117 samples form the basis for
the graphic interpretation appearing later in this report.
Further data available on request.
PROCESS
Due to process plant and tailings dam space constraints
at the original mine /plant site, pre-crushed material
is trucked by road more than 130 km into this location.
Typical road haul trucks are double haul of the land-train
variety (usually 2 × 22 metric ton trailers making up the
so-called “fulles” in Mexico).
This mineral material is approximately 58% fluorspar
(CaF2 -Specific Gravity of 3.1 Mohs hardness #4), with the
balance being silica from sandstone /mudstone /siltstone
(SG of 2.67 Mohs #7) and calcium carbonate (SG of 2.7
Mohs #3). Abrasiveness for the mixture is around Mohs
hardness #6 due to the significant load of silica present –
and for the total minerals feed mix the SG is quite high at
around 2.8.
Saving Water and Tailing Dam Space for Medium Size Mines—
A Case Study Using Centrifuge Technology to Recover Process
Water from Mine Tailings
Eric Gentis, Terry Ostrum, Stephen Benyo
Flottweg Separation Technology, Inc., Independence, KY
ABSTRACT: Traditionally, tailings dams or a chamber filter (plate-and-frame) presses are used to dewater
tailings. This solution requires significant capital investment and infrastructure. Dams do not recover much
process water, and presses are expensive and labor-intensive and neither are portable.
A reliable, cost-effective alternative is explored here. This paper reviews the results of a month-long trial of a pilot
plant using a decanter centrifuge that is specifically designed to withstand the rigors of a mining application.
INTRODUCTION AND OVERVIEW
The mining customer in this case study already owns several
Flottwe.g., Z92 (920mm bowl diameter) decanter centri-
fuges operating successfully (24/7) at their main processing
plant, dewatering their tailings and recovering most of their
(very) expensive process water.
They wished to run a smaller pilot unit at a different,
more remote location where they operate another process
plant, to check whether the conditions there are also suit-
able to invest in another battery of Z92s for this 2nd opera-
tion. They are rapidly depleting their current tailings dam
space at this site and have a very significant water cost due
to their location in central Mexico’s arid region.
Flottwe.g., provided a suitably wear-protected Z5E
mining decanter centrifuge (530mm bowl diameter) to run
as pilot for a month. This size unit can effectively mimic the
large unit operations and is regularly used for this kind of
scaleup predictability pilot in mining applications.
Operation of the pilot centrifuge was 24/7 during the
pilot period. Regular sampling of the input feed material,
the output solids and output liquid (centrate) was per-
formed by trained and well-qualified operations staff on
a regular basis throughout the pilot period. These samples
were analyzed for their solids &moisture contents on site
in the Flottwe.g., portable laboratory, immediately after
capture.
After installation and start-up, 117 separate tests were
taken over 12 days. These 117 samples form the basis for
the graphic interpretation appearing later in this report.
Further data available on request.
PROCESS
Due to process plant and tailings dam space constraints
at the original mine /plant site, pre-crushed material
is trucked by road more than 130 km into this location.
Typical road haul trucks are double haul of the land-train
variety (usually 2 × 22 metric ton trailers making up the
so-called “fulles” in Mexico).
This mineral material is approximately 58% fluorspar
(CaF2 -Specific Gravity of 3.1 Mohs hardness #4), with the
balance being silica from sandstone /mudstone /siltstone
(SG of 2.67 Mohs #7) and calcium carbonate (SG of 2.7
Mohs #3). Abrasiveness for the mixture is around Mohs
hardness #6 due to the significant load of silica present –
and for the total minerals feed mix the SG is quite high at
around 2.8.