PASTE & TAILINGS 2020
Hudbay Minerals paste backfill plant for Lalor
Thomas Skocir & Isaac Ahmed from Golder Associates Ltd
in Mississauga, Ontario, and Conor Blayney at Hudbay
Minerals Inc in Snow Lake, Manitoba, review the paste
backfill project completed at the Lalor mine in Manitoba
To improve on filling rate and to produce a
consistent, high quality backfill, Hudbay
looked to install a new paste backfill plant
at their Lalor zinc, gold and copper mine,
located in Snow Lake, Manitoba. Paste backfill
plants are not new to Hudbay, in fact, the
company operated one of the earliest facilities
at their Flin Flon operation, also located in
Manitoba. The Lalor Paste Backfill Plant is one
of the newest plants in Canada featuring state
of the art process control technology that allows
the facility to run with minimal operator
Hudbay’s Lalor Paste Backfill Plant located near Snow Lake, Manitoba plus a 3D model of the same
facility
intervention. The plant was commissioned in the
spring and early summer of 2018 and by late
summer, was in full operation.
There are some unique features to this
backfill plant. This includes the delivery of
tailings from the Stall Mill which is located 16
km away from the Lalor mine. A booster station,
situated adjacent to the tailings management
area (TMA) was designed to intercept the
tailings and pump them 13.5 km to the paste
backfill plant. Since there were no disposal or
treatment options at the mine, excess water
from dewatering of the tailings needed to be
pumped back 13.5 km to the TMA in a parallel
return line. The booster station was also
designed to deal with large swings in tailings
flow rates, and future increases in production.
A fibre optic cable was laid down along the
remote booster station line that provided
communications back to the paste plant.
Multiple leak detection stations were also set
up along the pipeline at critical locations and
monitored through the fibre optic network.
Environmental monitoring and compliance was
a key consideration during the design phase.
The Lalor Paste Backfill Plant has the unique
ability to store four days worth of tailings from
the mill through the use of two large agitated
filter feed tanks. This serves to both decouple
paste production from mill tailings delivery by
using the stored tailings and effectively allows
the paste backfill plant to pour at a sustained
higher rate than the mill tailings feed rate when
it is coupled. The paste plant design includes a
high rate thickener, large agitated tailings
storage tanks, 3.8 m diameter disc filter, belt
conveyor, cement silos with a loss in weight
feeder, multiple cement screw conveyors, and a
twin shaft mixer.
Paste is delivered to the underground mine
via twin boreholes (standby and operating)
located in the paste plant. The surface location
of the paste backfill plant allows for gravity flow
of paste to the stopes for backfilling. The plant
is designed to operate on a continuous basis
with sufficient redundancy, surge capacity and
provisions for emergency power to warrant an
optimal, safe and reliable operation.
Lalor was discovered in 2007 on 100% owned
land using Hudbay’s innovative exploration
techniques and it is the largest VMS deposit
found in the Snow Lake region to date. In
February 2020, Hudbay announced increased
mineral reserves and resources for the Lalor
mine and nearby satellite deposits, and a new
mine plan that includes the processing of gold
and copper-gold ore at the company’s New
Britannia mill. IM
P6 International Mining | SEPTEMBER 2020 Supplement