OPERATION FOCUS
Dolinny in focus
The Dolinny mine at full production
will produce 750,000 t/y of rock of
which 451,000 t/y will be ore. The
decision was made during the
mine design to utilise two declines
and three 2.7 m diameter
ventilation shafts which were sunk
using a Robbins raiseborer. One
large fan is being used or expelling
air with 32 additional fans
underground all using ventilation
on demand (VOD) to save energy
A Cat AD45 underground truck emerging from
the Dolinny production decline. The company
will transition to more continuous haulage in the
coming years with the installation of a Rail-Veyor
system
thickness different mining methods are used at
Ridder-Sokolny mine: level and sublevel caving;
cut-and-fill stoping; sublevel stoping with partial
shrinkage applied (ore veins); shrinkage stoping
(narrow ore veins); upward horizontal slicing
with backfilling; and sublevel caving (narrow ore
veins).
All RMCC production as stated is now
underground, and all production is by owner
operator fleets. Sandvik and Epiroc dealers
maintain their own machines under technical and
service contracts, with RMCC itself maintaining
the Cat fleets. At Dolinny major maintenance is
currently carried out on surface with minor
repairs carried in a new underground
maintenance bay. Across the rest of RMCC there
are underground and surface maintenance
shops.
Some contractors are used for special works
such as electrical infrastructure and ventilation
as well as during mine construction periods. All
drill and blast including explosives delivery and
management is also done in house by RMCC.
Dolinny has daily development blasting and
stope blasting five or six times per month
currently.
The ore route at Dolinny sees ore hauled by
LHDs from the stope (loaded with line of sight RC
or semi/full autonomous), with dumping into a
reloading bay and transfer underground trucks
which drive directly out of the decline which
starts at 600 m; ten truck trips are usually made
per shift. At Tishinsky and Ridder-Sokolny the
trucks load underground conveyors which load
skip hoists. Ridder ore goes direct to the
concentrator, while Tishinsky ore has an on-site
heavy media separation plant that produces a
heavy ore fraction that goes by rail to the
concentrator along with slimes. As stated the
light fraction is mainly waste used for
backfill.
International Mining | FEBRUARY 2020
costs. Russian mine ventilation
software is being used to control
airflow volumes.
One decline is utilities dedicated – for water
and air supply and is 2.4 km long, with the main
haulage decline being 4.5 km long. The ore
haulage at Dolinny is currently conventional with
three Cat R1700 LHDs plus four Cat AD45 45 t
underground trucks and one AD60 brought in for
large heading development. The Cat equipment
was supplied by Kazakh dealer Borusan Makina.
The declines are supported with mesh and
shotcrete on the roof and walls being
permanently in use, while the production areas
are bolted and meshed if the ground conditions
require it. The headings are 23 m 2 , 5 m high and
4.5 m wide. Shotcreting is done by a Normet
unit; bolting is done currently with the
development rigs but the mine is looking into
buying two dedicated Sandvik bolters. Decline
and road maintenance is carried out with a new
UG20K underground motor grader which is a
modified Cat machine.
However, things are soon to change. During
the IM visit RMCC Director Kotov said that it is
looking at installing an electrically powered Rail-
Veyor system to both achieve more continuous
production and of course massively reduce its
diesel emissions. This is a technology that
combines the flexibility of truck hauling with the
energy efficiency of conveyors and rail lines.
Essentially, it uses low-profile steel cars in either
30 or 48 in widths which
link together with a spill-
proof connection to create
a continuous U-shaped
trough; electric motors
drive horizontal wheels,
making contact with side
plates to move cars forward
and back. To discharge
materials, cars are inverted
into a continuous loop that
can be run 180 or 360-
degrees, easily dumping
into a stockpile, bin or
crusher. The Rail-Veyor system is proven to work
on grades up to 22%. The system has already
been used at several big metallic operations
namely Goldex Deep 1, Vale Copper Cliff Orebody
114 and Doe Run Casteel mine. So Dolinny may
become the first big installation outside of North
America, which will be a major boost for Rail-
Veyor.
Any new Rail-Veyor heading dimensions will
be slightly smaller at 19-20 m 2 or 4 m by 5 m.
The intention is still to use the underground
truck fleet during a transition period as it will
take some time to install the Rail-Veyor system
over two phases. The Rail-Veyor system at
Dolinny will ultimately be extended to connect
the Dolinnoe deposit underground with the
nearby Obruchevsky deposit some 2.4 km away
via two more underground declines. The Rail-
Veyor system will connect will multiple ore
passes, three at Dolinny and three at
Obruchevsky with the ore ultimately emerging at
the Dolinny Rail-Veyor decline that currently uses
trucks. On surface the ore will be sorted into
three ore type stockpiles. RMCC Director Kotov
said that if the Rail-Veyor system works well at
Dolinny they may look at replicating it at other
operations.
In terms of water issues, there is a natural
influx of some 160-180 m 3 /hour of water into
Dolinny that is pumped out. This will increase to
450 m 3 /hour as the mine deepens and the
Obruchevsky deposit is developed and a special
new pumping station using Russian dewatering
pumps is being designed to handle this.
Until 2019 the mine used granular ANFO but
has switched to emulsion as it is water based
and therefore not affected by water in the mine
as well as being more powerful and not
producing the same level of CO emissions.
Explosives are sourced from the Orica operation
in Ust-Kamenogorsk.
Exploration work continues underground,
using Epiroc Diamec diamond coring rigs. The
mine used to drill a hole every 25 m but this is
now every 12.5 m to help better understand the
gold mineralisation. Currently at Dolinny over 22
km of exploration holes are being drilled every
Main Building 2 at RMCC concentrator showing
milling and filtering lines